+++ /dev/null
-/* $Id: evdns.c 6979 2006-08-04 18:31:13Z nickm $ */
-
-/* The original version of this module was written by Adam Langley; for
- * a history of modifications, check out the subversion logs.
- *
- * When editing this module, try to keep it re-mergeable by Adam. Don't
- * reformat the whitespace, add Tor dependencies, or so on.
- *
- * TODO:
- * - Support IPv6 and PTR records.
- * - Replace all externally visible magic numbers with #defined constants.
- * - Write documentation for APIs of all external functions.
- */
-
-/* Async DNS Library
- * Adam Langley <agl@imperialviolet.org>
- * http://www.imperialviolet.org/eventdns.html
- * Public Domain code
- *
- * This software is Public Domain. To view a copy of the public domain dedication,
- * visit http://creativecommons.org/licenses/publicdomain/ or send a letter to
- * Creative Commons, 559 Nathan Abbott Way, Stanford, California 94305, USA.
- *
- * I ask and expect, but do not require, that all derivative works contain an
- * attribution similar to:
- * Parts developed by Adam Langley <agl@imperialviolet.org>
- *
- * You may wish to replace the word "Parts" with something else depending on
- * the amount of original code.
- *
- * (Derivative works does not include programs which link against, run or include
- * the source verbatim in their source distributions)
- *
- * Version: 0.1b
- */
-
-#include <sys/types.h>
-#include "event2/event-config.h"
-
-#ifndef _FORTIFY_SOURCE
-#define _FORTIFY_SOURCE 3
-#endif
-
-#include <string.h>
-#include <fcntl.h>
-#ifdef _EVENT_HAVE_SYS_TIME_H
-#include <sys/time.h>
-#endif
-#ifdef _EVENT_HAVE_STDINT_H
-#include <stdint.h>
-#endif
-#include <stdlib.h>
-#include <string.h>
-#include <errno.h>
-#ifdef _EVENT_HAVE_UNISTD_H
-#include <unistd.h>
-#endif
-#include <limits.h>
-#include <sys/stat.h>
-#include <stdio.h>
-#include <stdarg.h>
-#ifdef WIN32
-#include <winsock2.h>
-#include <ws2tcpip.h>
-#ifndef _WIN32_IE
-#define _WIN32_IE 0x400
-#endif
-#include <shlobj.h>
-#endif
-
-#include "event2/dns.h"
-#include "event2/dns_struct.h"
-#include "event2/dns_compat.h"
-#include "event2/util.h"
-#include "event2/event.h"
-#include "event2/event_struct.h"
-#include "event2/thread.h"
-
-#include "event2/bufferevent.h"
-#include "event2/bufferevent_struct.h"
-#include "bufferevent-internal.h"
-
-#include "defer-internal.h"
-#include "log-internal.h"
-#include "mm-internal.h"
-#include "strlcpy-internal.h"
-#include "ipv6-internal.h"
-#include "util-internal.h"
-#include "evthread-internal.h"
-#ifdef WIN32
-#include <ctype.h>
-#include <winsock2.h>
-#include <windows.h>
-#include <iphlpapi.h>
-#include <io.h>
-#else
-#include <sys/socket.h>
-#include <netinet/in.h>
-#include <arpa/inet.h>
-#endif
-
-#ifdef _EVENT_HAVE_NETINET_IN6_H
-#include <netinet/in6.h>
-#endif
-
-#define EVDNS_LOG_DEBUG 0
-#define EVDNS_LOG_WARN 1
-#define EVDNS_LOG_MSG 2
-
-#ifndef HOST_NAME_MAX
-#define HOST_NAME_MAX 255
-#endif
-
-#include <stdio.h>
-
-#undef MIN
-#define MIN(a,b) ((a)<(b)?(a):(b))
-
-#define ASSERT_VALID_REQUEST(req) \
- EVUTIL_ASSERT((req)->handle && (req)->handle->current_req == (req))
-
-#define u64 ev_uint64_t
-#define u32 ev_uint32_t
-#define u16 ev_uint16_t
-#define u8 ev_uint8_t
-
-/* maximum number of addresses from a single packet */
-/* that we bother recording */
-#define MAX_V4_ADDRS 32
-#define MAX_V6_ADDRS 32
-
-
-#define TYPE_A EVDNS_TYPE_A
-#define TYPE_CNAME 5
-#define TYPE_PTR EVDNS_TYPE_PTR
-#define TYPE_AAAA EVDNS_TYPE_AAAA
-
-#define CLASS_INET EVDNS_CLASS_INET
-
-/* Persistent handle. We keep this separate from 'struct request' since we
- * need some object to last for as long as an evdns_request is outstanding so
- * that it can be canceled, whereas a search request can lead to multiple
- * 'struct request' instances being created over its lifetime. */
-struct evdns_request {
- struct request *current_req;
- struct evdns_base *base;
-
- int pending_cb; /* Waiting for its callback to be invoked; not
- * owned by event base any more. */
-
- /* elements used by the searching code */
- int search_index;
- struct search_state *search_state;
- char *search_origname; /* needs to be free()ed */
- int search_flags;
-};
-
-struct request {
- u8 *request; /* the dns packet data */
- u8 request_type; /* TYPE_PTR or TYPE_A or TYPE_AAAA */
- unsigned int request_len;
- int reissue_count;
- int tx_count; /* the number of times that this packet has been sent */
- void *user_pointer; /* the pointer given to us for this request */
- evdns_callback_type user_callback;
- struct nameserver *ns; /* the server which we last sent it */
-
- /* these objects are kept in a circular list */
- struct request *next, *prev;
-
- struct event timeout_event;
-
- u16 trans_id; /* the transaction id */
- unsigned request_appended :1; /* true if the request pointer is data which follows this struct */
- unsigned transmit_me :1; /* needs to be transmitted */
-
- /* XXXX This is a horrible hack. */
- char **put_cname_in_ptr; /* store the cname here if we get one. */
-
- struct evdns_base *base;
-
- struct evdns_request *handle;
-};
-
-struct reply {
- unsigned int type;
- unsigned int have_answer : 1;
- union {
- struct {
- u32 addrcount;
- u32 addresses[MAX_V4_ADDRS];
- } a;
- struct {
- u32 addrcount;
- struct in6_addr addresses[MAX_V6_ADDRS];
- } aaaa;
- struct {
- char name[HOST_NAME_MAX];
- } ptr;
- } data;
-};
-
-struct nameserver {
- evutil_socket_t socket; /* a connected UDP socket */
- struct sockaddr_storage address;
- ev_socklen_t addrlen;
- int failed_times; /* number of times which we have given this server a chance */
- int timedout; /* number of times in a row a request has timed out */
- struct event event;
- /* these objects are kept in a circular list */
- struct nameserver *next, *prev;
- struct event timeout_event; /* used to keep the timeout for */
- /* when we next probe this server. */
- /* Valid if state == 0 */
- /* Outstanding probe request for this nameserver, if any */
- struct evdns_request *probe_request;
- char state; /* zero if we think that this server is down */
- char choked; /* true if we have an EAGAIN from this server's socket */
- char write_waiting; /* true if we are waiting for EV_WRITE events */
- struct evdns_base *base;
-};
-
-
-/* Represents a local port where we're listening for DNS requests. Right now, */
-/* only UDP is supported. */
-struct evdns_server_port {
- evutil_socket_t socket; /* socket we use to read queries and write replies. */
- int refcnt; /* reference count. */
- char choked; /* Are we currently blocked from writing? */
- char closing; /* Are we trying to close this port, pending writes? */
- evdns_request_callback_fn_type user_callback; /* Fn to handle requests */
- void *user_data; /* Opaque pointer passed to user_callback */
- struct event event; /* Read/write event */
- /* circular list of replies that we want to write. */
- struct server_request *pending_replies;
- struct event_base *event_base;
-
-#ifndef _EVENT_DISABLE_THREAD_SUPPORT
- void *lock;
-#endif
-};
-
-/* Represents part of a reply being built. (That is, a single RR.) */
-struct server_reply_item {
- struct server_reply_item *next; /* next item in sequence. */
- char *name; /* name part of the RR */
- u16 type; /* The RR type */
- u16 class; /* The RR class (usually CLASS_INET) */
- u32 ttl; /* The RR TTL */
- char is_name; /* True iff data is a label */
- u16 datalen; /* Length of data; -1 if data is a label */
- void *data; /* The contents of the RR */
-};
-
-/* Represents a request that we've received as a DNS server, and holds */
-/* the components of the reply as we're constructing it. */
-struct server_request {
- /* Pointers to the next and previous entries on the list of replies */
- /* that we're waiting to write. Only set if we have tried to respond */
- /* and gotten EAGAIN. */
- struct server_request *next_pending;
- struct server_request *prev_pending;
-
- u16 trans_id; /* Transaction id. */
- struct evdns_server_port *port; /* Which port received this request on? */
- struct sockaddr_storage addr; /* Where to send the response */
- ev_socklen_t addrlen; /* length of addr */
-
- int n_answer; /* how many answer RRs have been set? */
- int n_authority; /* how many authority RRs have been set? */
- int n_additional; /* how many additional RRs have been set? */
-
- struct server_reply_item *answer; /* linked list of answer RRs */
- struct server_reply_item *authority; /* linked list of authority RRs */
- struct server_reply_item *additional; /* linked list of additional RRs */
-
- /* Constructed response. Only set once we're ready to send a reply. */
- /* Once this is set, the RR fields are cleared, and no more should be set. */
- char *response;
- size_t response_len;
-
- /* Caller-visible fields: flags, questions. */
- struct evdns_server_request base;
-};
-
-struct evdns_base {
- /* An array of n_req_heads circular lists for inflight requests.
- * Each inflight request req is in req_heads[req->trans_id % n_req_heads].
- */
- struct request **req_heads;
- /* A circular list of requests that we're waiting to send, but haven't
- * sent yet because there are too many requests inflight */
- struct request *req_waiting_head;
- /* A circular list of nameservers. */
- struct nameserver *server_head;
- int n_req_heads;
-
- struct event_base *event_base;
-
- /* The number of good nameservers that we have */
- int global_good_nameservers;
-
- /* inflight requests are contained in the req_head list */
- /* and are actually going out across the network */
- int global_requests_inflight;
- /* requests which aren't inflight are in the waiting list */
- /* and are counted here */
- int global_requests_waiting;
-
- int global_max_requests_inflight;
-
- struct timeval global_timeout; /* 5 seconds by default */
- int global_max_reissues; /* a reissue occurs when we get some errors from the server */
- int global_max_retransmits; /* number of times we'll retransmit a request which timed out */
- /* number of timeouts in a row before we consider this server to be down */
- int global_max_nameserver_timeout;
- /* true iff we will use the 0x20 hack to prevent poisoning attacks. */
- int global_randomize_case;
-
- /* The first time that a nameserver fails, how long do we wait before
- * probing to see if it has returned? */
- struct timeval global_nameserver_probe_initial_timeout;
-
- /** Port to bind to for outgoing DNS packets. */
- struct sockaddr_storage global_outgoing_address;
- /** ev_socklen_t for global_outgoing_address. 0 if it isn't set. */
- ev_socklen_t global_outgoing_addrlen;
-
- struct timeval global_getaddrinfo_allow_skew;
-
- int getaddrinfo_ipv4_timeouts;
- int getaddrinfo_ipv6_timeouts;
- int getaddrinfo_ipv4_answered;
- int getaddrinfo_ipv6_answered;
-
- struct search_state *global_search_state;
-
- TAILQ_HEAD(hosts_list, hosts_entry) hostsdb;
-
-#ifndef _EVENT_DISABLE_THREAD_SUPPORT
- void *lock;
-#endif
-};
-
-struct hosts_entry {
- TAILQ_ENTRY(hosts_entry) next;
- union {
- struct sockaddr sa;
- struct sockaddr_in sin;
- struct sockaddr_in6 sin6;
- } addr;
- int addrlen;
- char hostname[1];
-};
-
-static struct evdns_base *current_base = NULL;
-
-struct evdns_base *
-evdns_get_global_base(void)
-{
- return current_base;
-}
-
-/* Given a pointer to an evdns_server_request, get the corresponding */
-/* server_request. */
-#define TO_SERVER_REQUEST(base_ptr) \
- ((struct server_request*) \
- (((char*)(base_ptr) - evutil_offsetof(struct server_request, base))))
-
-#define REQ_HEAD(base, id) ((base)->req_heads[id % (base)->n_req_heads])
-
-static struct nameserver *nameserver_pick(struct evdns_base *base);
-static void evdns_request_insert(struct request *req, struct request **head);
-static void evdns_request_remove(struct request *req, struct request **head);
-static void nameserver_ready_callback(evutil_socket_t fd, short events, void *arg);
-static int evdns_transmit(struct evdns_base *base);
-static int evdns_request_transmit(struct request *req);
-static void nameserver_send_probe(struct nameserver *const ns);
-static void search_request_finished(struct evdns_request *const);
-static int search_try_next(struct evdns_request *const req);
-static struct request *search_request_new(struct evdns_base *base, struct evdns_request *handle, int type, const char *const name, int flags, evdns_callback_type user_callback, void *user_arg);
-static void evdns_requests_pump_waiting_queue(struct evdns_base *base);
-static u16 transaction_id_pick(struct evdns_base *base);
-static struct request *request_new(struct evdns_base *base, struct evdns_request *handle, int type, const char *name, int flags, evdns_callback_type callback, void *ptr);
-static void request_submit(struct request *const req);
-
-static int server_request_free(struct server_request *req);
-static void server_request_free_answers(struct server_request *req);
-static void server_port_free(struct evdns_server_port *port);
-static void server_port_ready_callback(evutil_socket_t fd, short events, void *arg);
-static int evdns_base_resolv_conf_parse_impl(struct evdns_base *base, int flags, const char *const filename);
-static int evdns_base_set_option_impl(struct evdns_base *base,
- const char *option, const char *val, int flags);
-static void evdns_base_free_and_unlock(struct evdns_base *base, int fail_requests);
-
-static int strtoint(const char *const str);
-
-#ifdef _EVENT_DISABLE_THREAD_SUPPORT
-#define EVDNS_LOCK(base) _EVUTIL_NIL_STMT
-#define EVDNS_UNLOCK(base) _EVUTIL_NIL_STMT
-#define ASSERT_LOCKED(base) _EVUTIL_NIL_STMT
-#else
-#define EVDNS_LOCK(base) \
- EVLOCK_LOCK((base)->lock, 0)
-#define EVDNS_UNLOCK(base) \
- EVLOCK_UNLOCK((base)->lock, 0)
-#define ASSERT_LOCKED(base) \
- EVLOCK_ASSERT_LOCKED((base)->lock)
-#endif
-
-static void
-default_evdns_log_fn(int warning, const char *buf)
-{
- if (warning == EVDNS_LOG_WARN)
- event_warnx("[evdns] %s", buf);
- else if (warning == EVDNS_LOG_MSG)
- event_msgx("[evdns] %s", buf);
- else
- event_debug(("[evdns] %s", buf));
-}
-
-static evdns_debug_log_fn_type evdns_log_fn = NULL;
-
-void
-evdns_set_log_fn(evdns_debug_log_fn_type fn)
-{
- evdns_log_fn = fn;
-}
-
-#ifdef __GNUC__
-#define EVDNS_LOG_CHECK __attribute__ ((format(printf, 2, 3)))
-#else
-#define EVDNS_LOG_CHECK
-#endif
-
-static void _evdns_log(int warn, const char *fmt, ...) EVDNS_LOG_CHECK;
-static void
-_evdns_log(int warn, const char *fmt, ...)
-{
- va_list args;
- char buf[512];
- if (!evdns_log_fn)
- return;
- va_start(args,fmt);
- evutil_vsnprintf(buf, sizeof(buf), fmt, args);
- va_end(args);
- if (evdns_log_fn) {
- if (warn == EVDNS_LOG_MSG)
- warn = EVDNS_LOG_WARN;
- evdns_log_fn(warn, buf);
- } else {
- default_evdns_log_fn(warn, buf);
- }
-
-}
-
-#define log _evdns_log
-
-/* This walks the list of inflight requests to find the */
-/* one with a matching transaction id. Returns NULL on */
-/* failure */
-static struct request *
-request_find_from_trans_id(struct evdns_base *base, u16 trans_id) {
- struct request *req = REQ_HEAD(base, trans_id);
- struct request *const started_at = req;
-
- ASSERT_LOCKED(base);
-
- if (req) {
- do {
- if (req->trans_id == trans_id) return req;
- req = req->next;
- } while (req != started_at);
- }
-
- return NULL;
-}
-
-/* a libevent callback function which is called when a nameserver */
-/* has gone down and we want to test if it has came back to life yet */
-static void
-nameserver_prod_callback(evutil_socket_t fd, short events, void *arg) {
- struct nameserver *const ns = (struct nameserver *) arg;
- (void)fd;
- (void)events;
-
- EVDNS_LOCK(ns->base);
- nameserver_send_probe(ns);
- EVDNS_UNLOCK(ns->base);
-}
-
-/* a libevent callback which is called when a nameserver probe (to see if */
-/* it has come back to life) times out. We increment the count of failed_times */
-/* and wait longer to send the next probe packet. */
-static void
-nameserver_probe_failed(struct nameserver *const ns) {
- struct timeval timeout;
- int i;
-
- ASSERT_LOCKED(ns->base);
- (void) evtimer_del(&ns->timeout_event);
- if (ns->state == 1) {
- /* This can happen if the nameserver acts in a way which makes us mark */
- /* it as bad and then starts sending good replies. */
- return;
- }
-
-#define MAX_PROBE_TIMEOUT 3600
-#define TIMEOUT_BACKOFF_FACTOR 3
-
- memcpy(&timeout, &ns->base->global_nameserver_probe_initial_timeout,
- sizeof(struct timeval));
- for (i=ns->failed_times; i > 0 && timeout.tv_sec < MAX_PROBE_TIMEOUT; --i) {
- timeout.tv_sec *= TIMEOUT_BACKOFF_FACTOR;
- timeout.tv_usec *= TIMEOUT_BACKOFF_FACTOR;
- if (timeout.tv_usec > 1000000) {
- timeout.tv_sec += timeout.tv_usec / 1000000;
- timeout.tv_usec %= 1000000;
- }
- }
- if (timeout.tv_sec > MAX_PROBE_TIMEOUT) {
- timeout.tv_sec = MAX_PROBE_TIMEOUT;
- timeout.tv_usec = 0;
- }
-
- ns->failed_times++;
-
- if (evtimer_add(&ns->timeout_event, &timeout) < 0) {
- char addrbuf[128];
- log(EVDNS_LOG_WARN,
- "Error from libevent when adding timer event for %s",
- evutil_format_sockaddr_port(
- (struct sockaddr *)&ns->address,
- addrbuf, sizeof(addrbuf)));
- }
-}
-
-/* called when a nameserver has been deemed to have failed. For example, too */
-/* many packets have timed out etc */
-static void
-nameserver_failed(struct nameserver *const ns, const char *msg) {
- struct request *req, *started_at;
- struct evdns_base *base = ns->base;
- int i;
- char addrbuf[128];
-
- ASSERT_LOCKED(base);
- /* if this nameserver has already been marked as failed */
- /* then don't do anything */
- if (!ns->state) return;
-
- log(EVDNS_LOG_MSG, "Nameserver %s has failed: %s",
- evutil_format_sockaddr_port(
- (struct sockaddr *)&ns->address,
- addrbuf, sizeof(addrbuf)),
- msg);
-
- base->global_good_nameservers--;
- EVUTIL_ASSERT(base->global_good_nameservers >= 0);
- if (base->global_good_nameservers == 0) {
- log(EVDNS_LOG_MSG, "All nameservers have failed");
- }
-
- ns->state = 0;
- ns->failed_times = 1;
-
- if (evtimer_add(&ns->timeout_event,
- &base->global_nameserver_probe_initial_timeout) < 0) {
- log(EVDNS_LOG_WARN,
- "Error from libevent when adding timer event for %s",
- evutil_format_sockaddr_port(
- (struct sockaddr *)&ns->address,
- addrbuf, sizeof(addrbuf)));
- /* ???? Do more? */
- }
-
- /* walk the list of inflight requests to see if any can be reassigned to */
- /* a different server. Requests in the waiting queue don't have a */
- /* nameserver assigned yet */
-
- /* if we don't have *any* good nameservers then there's no point */
- /* trying to reassign requests to one */
- if (!base->global_good_nameservers) return;
-
- for (i = 0; i < base->n_req_heads; ++i) {
- req = started_at = base->req_heads[i];
- if (req) {
- do {
- if (req->tx_count == 0 && req->ns == ns) {
- /* still waiting to go out, can be moved */
- /* to another server */
- req->ns = nameserver_pick(base);
- }
- req = req->next;
- } while (req != started_at);
- }
- }
-}
-
-static void
-nameserver_up(struct nameserver *const ns)
-{
- char addrbuf[128];
- ASSERT_LOCKED(ns->base);
- if (ns->state) return;
- log(EVDNS_LOG_MSG, "Nameserver %s is back up",
- evutil_format_sockaddr_port(
- (struct sockaddr *)&ns->address,
- addrbuf, sizeof(addrbuf)));
- evtimer_del(&ns->timeout_event);
- if (ns->probe_request) {
- evdns_cancel_request(ns->base, ns->probe_request);
- ns->probe_request = NULL;
- }
- ns->state = 1;
- ns->failed_times = 0;
- ns->timedout = 0;
- ns->base->global_good_nameservers++;
-}
-
-static void
-request_trans_id_set(struct request *const req, const u16 trans_id) {
- req->trans_id = trans_id;
- *((u16 *) req->request) = htons(trans_id);
-}
-
-/* Called to remove a request from a list and dealloc it. */
-/* head is a pointer to the head of the list it should be */
-/* removed from or NULL if the request isn't in a list. */
-/* when free_handle is one, free the handle as well. */
-static void
-request_finished(struct request *const req, struct request **head, int free_handle) {
- struct evdns_base *base = req->base;
- int was_inflight = (head != &base->req_waiting_head);
- EVDNS_LOCK(base);
- ASSERT_VALID_REQUEST(req);
-
- if (head)
- evdns_request_remove(req, head);
-
- log(EVDNS_LOG_DEBUG, "Removing timeout for request %p", req);
- if (was_inflight) {
- evtimer_del(&req->timeout_event);
- base->global_requests_inflight--;
- } else {
- base->global_requests_waiting--;
- }
-
- if (!req->request_appended) {
- /* need to free the request data on it's own */
- mm_free(req->request);
- } else {
- /* the request data is appended onto the header */
- /* so everything gets free()ed when we: */
- }
-
- if (req->handle) {
- EVUTIL_ASSERT(req->handle->current_req == req);
-
- if (free_handle) {
- search_request_finished(req->handle);
- req->handle->current_req = NULL;
- if (! req->handle->pending_cb) {
- /* If we're planning to run the callback,
- * don't free the handle until later. */
- mm_free(req->handle);
- }
- req->handle = NULL; /* If we have a bug, let's crash
- * early */
- } else {
- req->handle->current_req = NULL;
- }
- }
-
- mm_free(req);
-
- evdns_requests_pump_waiting_queue(base);
- EVDNS_UNLOCK(base);
-}
-
-/* This is called when a server returns a funny error code. */
-/* We try the request again with another server. */
-/* */
-/* return: */
-/* 0 ok */
-/* 1 failed/reissue is pointless */
-static int
-request_reissue(struct request *req) {
- const struct nameserver *const last_ns = req->ns;
- ASSERT_LOCKED(req->base);
- ASSERT_VALID_REQUEST(req);
- /* the last nameserver should have been marked as failing */
- /* by the caller of this function, therefore pick will try */
- /* not to return it */
- req->ns = nameserver_pick(req->base);
- if (req->ns == last_ns) {
- /* ... but pick did return it */
- /* not a lot of point in trying again with the */
- /* same server */
- return 1;
- }
-
- req->reissue_count++;
- req->tx_count = 0;
- req->transmit_me = 1;
-
- return 0;
-}
-
-/* this function looks for space on the inflight queue and promotes */
-/* requests from the waiting queue if it can. */
-static void
-evdns_requests_pump_waiting_queue(struct evdns_base *base) {
- ASSERT_LOCKED(base);
- while (base->global_requests_inflight < base->global_max_requests_inflight &&
- base->global_requests_waiting) {
- struct request *req;
- /* move a request from the waiting queue to the inflight queue */
- EVUTIL_ASSERT(base->req_waiting_head);
- req = base->req_waiting_head;
- evdns_request_remove(req, &base->req_waiting_head);
-
- base->global_requests_waiting--;
- base->global_requests_inflight++;
-
- req->ns = nameserver_pick(base);
- request_trans_id_set(req, transaction_id_pick(base));
-
- evdns_request_insert(req, &REQ_HEAD(base, req->trans_id));
- evdns_request_transmit(req);
- evdns_transmit(base);
- }
-}
-
-/* TODO(nickm) document */
-struct deferred_reply_callback {
- struct deferred_cb deferred;
- struct evdns_request *handle;
- u8 request_type;
- u8 have_reply;
- u32 ttl;
- u32 err;
- evdns_callback_type user_callback;
- struct reply reply;
-};
-
-static void
-reply_run_callback(struct deferred_cb *d, void *user_pointer)
-{
- struct deferred_reply_callback *cb =
- EVUTIL_UPCAST(d, struct deferred_reply_callback, deferred);
-
- switch (cb->request_type) {
- case TYPE_A:
- if (cb->have_reply)
- cb->user_callback(DNS_ERR_NONE, DNS_IPv4_A,
- cb->reply.data.a.addrcount, cb->ttl,
- cb->reply.data.a.addresses,
- user_pointer);
- else
- cb->user_callback(cb->err, 0, 0, 0, NULL, user_pointer);
- break;
- case TYPE_PTR:
- if (cb->have_reply) {
- char *name = cb->reply.data.ptr.name;
- cb->user_callback(DNS_ERR_NONE, DNS_PTR, 1, cb->ttl,
- &name, user_pointer);
- } else {
- cb->user_callback(cb->err, 0, 0, 0, NULL, user_pointer);
- }
- break;
- case TYPE_AAAA:
- if (cb->have_reply)
- cb->user_callback(DNS_ERR_NONE, DNS_IPv6_AAAA,
- cb->reply.data.aaaa.addrcount, cb->ttl,
- cb->reply.data.aaaa.addresses,
- user_pointer);
- else
- cb->user_callback(cb->err, 0, 0, 0, NULL, user_pointer);
- break;
- default:
- EVUTIL_ASSERT(0);
- }
-
- if (cb->handle && cb->handle->pending_cb) {
- mm_free(cb->handle);
- }
-
- mm_free(cb);
-}
-
-static void
-reply_schedule_callback(struct request *const req, u32 ttl, u32 err, struct reply *reply)
-{
- struct deferred_reply_callback *d = mm_calloc(1, sizeof(*d));
-
- if (!d) {
- event_warn("%s: Couldn't allocate space for deferred callback.",
- __func__);
- return;
- }
-
- ASSERT_LOCKED(req->base);
-
- d->request_type = req->request_type;
- d->user_callback = req->user_callback;
- d->ttl = ttl;
- d->err = err;
- if (reply) {
- d->have_reply = 1;
- memcpy(&d->reply, reply, sizeof(struct reply));
- }
-
- if (req->handle) {
- req->handle->pending_cb = 1;
- d->handle = req->handle;
- }
-
- event_deferred_cb_init(&d->deferred, reply_run_callback,
- req->user_pointer);
- event_deferred_cb_schedule(
- event_base_get_deferred_cb_queue(req->base->event_base),
- &d->deferred);
-}
-
-/* this processes a parsed reply packet */
-static void
-reply_handle(struct request *const req, u16 flags, u32 ttl, struct reply *reply) {
- int error;
- char addrbuf[128];
- static const int error_codes[] = {
- DNS_ERR_FORMAT, DNS_ERR_SERVERFAILED, DNS_ERR_NOTEXIST,
- DNS_ERR_NOTIMPL, DNS_ERR_REFUSED
- };
-
- ASSERT_LOCKED(req->base);
- ASSERT_VALID_REQUEST(req);
-
- if (flags & 0x020f || !reply || !reply->have_answer) {
- /* there was an error */
- if (flags & 0x0200) {
- error = DNS_ERR_TRUNCATED;
- } else {
- u16 error_code = (flags & 0x000f) - 1;
- if (error_code > 4) {
- error = DNS_ERR_UNKNOWN;
- } else {
- error = error_codes[error_code];
- }
- }
-
- switch (error) {
- case DNS_ERR_NOTIMPL:
- case DNS_ERR_REFUSED:
- /* we regard these errors as marking a bad nameserver */
- if (req->reissue_count < req->base->global_max_reissues) {
- char msg[64];
- evutil_snprintf(msg, sizeof(msg), "Bad response %d (%s)",
- error, evdns_err_to_string(error));
- nameserver_failed(req->ns, msg);
- if (!request_reissue(req)) return;
- }
- break;
- case DNS_ERR_SERVERFAILED:
- /* rcode 2 (servfailed) sometimes means "we
- * are broken" and sometimes (with some binds)
- * means "that request was very confusing."
- * Treat this as a timeout, not a failure.
- */
- log(EVDNS_LOG_DEBUG, "Got a SERVERFAILED from nameserver"
- "at %s; will allow the request to time out.",
- evutil_format_sockaddr_port(
- (struct sockaddr *)&req->ns->address,
- addrbuf, sizeof(addrbuf)));
- break;
- default:
- /* we got a good reply from the nameserver */
- nameserver_up(req->ns);
- }
-
- if (req->handle->search_state &&
- req->request_type != TYPE_PTR) {
- /* if we have a list of domains to search in,
- * try the next one */
- if (!search_try_next(req->handle)) {
- /* a new request was issued so this
- * request is finished and */
- /* the user callback will be made when
- * that request (or a */
- /* child of it) finishes. */
- return;
- }
- }
-
- /* all else failed. Pass the failure up */
- reply_schedule_callback(req, 0, error, NULL);
- request_finished(req, &REQ_HEAD(req->base, req->trans_id), 1);
- } else {
- /* all ok, tell the user */
- reply_schedule_callback(req, ttl, 0, reply);
- if (req->handle == req->ns->probe_request)
- req->ns->probe_request = NULL; /* Avoid double-free */
- nameserver_up(req->ns);
- request_finished(req, &REQ_HEAD(req->base, req->trans_id), 1);
- }
-}
-
-static int
-name_parse(u8 *packet, int length, int *idx, char *name_out, int name_out_len) {
- int name_end = -1;
- int j = *idx;
- int ptr_count = 0;
-#define GET32(x) do { if (j + 4 > length) goto err; memcpy(&_t32, packet + j, 4); j += 4; x = ntohl(_t32); } while (0)
-#define GET16(x) do { if (j + 2 > length) goto err; memcpy(&_t, packet + j, 2); j += 2; x = ntohs(_t); } while (0)
-#define GET8(x) do { if (j >= length) goto err; x = packet[j++]; } while (0)
-
- char *cp = name_out;
- const char *const end = name_out + name_out_len;
-
- /* Normally, names are a series of length prefixed strings terminated */
- /* with a length of 0 (the lengths are u8's < 63). */
- /* However, the length can start with a pair of 1 bits and that */
- /* means that the next 14 bits are a pointer within the current */
- /* packet. */
-
- for (;;) {
- u8 label_len;
- if (j >= length) return -1;
- GET8(label_len);
- if (!label_len) break;
- if (label_len & 0xc0) {
- u8 ptr_low;
- GET8(ptr_low);
- if (name_end < 0) name_end = j;
- j = (((int)label_len & 0x3f) << 8) + ptr_low;
- /* Make sure that the target offset is in-bounds. */
- if (j < 0 || j >= length) return -1;
- /* If we've jumped more times than there are characters in the
- * message, we must have a loop. */
- if (++ptr_count > length) return -1;
- continue;
- }
- if (label_len > 63) return -1;
- if (cp != name_out) {
- if (cp + 1 >= end) return -1;
- *cp++ = '.';
- }
- if (cp + label_len >= end) return -1;
- memcpy(cp, packet + j, label_len);
- cp += label_len;
- j += label_len;
- }
- if (cp >= end) return -1;
- *cp = '\0';
- if (name_end < 0)
- *idx = j;
- else
- *idx = name_end;
- return 0;
- err:
- return -1;
-}
-
-/* parses a raw request from a nameserver */
-static int
-reply_parse(struct evdns_base *base, u8 *packet, int length) {
- int j = 0, k = 0; /* index into packet */
- u16 _t; /* used by the macros */
- u32 _t32; /* used by the macros */
- char tmp_name[256], cmp_name[256]; /* used by the macros */
- int name_matches = 0;
-
- u16 trans_id, questions, answers, authority, additional, datalength;
- u16 flags = 0;
- u32 ttl, ttl_r = 0xffffffff;
- struct reply reply;
- struct request *req = NULL;
- unsigned int i;
-
- ASSERT_LOCKED(base);
-
- GET16(trans_id);
- GET16(flags);
- GET16(questions);
- GET16(answers);
- GET16(authority);
- GET16(additional);
- (void) authority; /* suppress "unused variable" warnings. */
- (void) additional; /* suppress "unused variable" warnings. */
-
- req = request_find_from_trans_id(base, trans_id);
- if (!req) return -1;
- EVUTIL_ASSERT(req->base == base);
-
- memset(&reply, 0, sizeof(reply));
-
- /* If it's not an answer, it doesn't correspond to any request. */
- if (!(flags & 0x8000)) return -1; /* must be an answer */
- if (flags & 0x020f) {
- /* there was an error */
- goto err;
- }
- /* if (!answers) return; */ /* must have an answer of some form */
-
- /* This macro skips a name in the DNS reply. */
-#define SKIP_NAME \
- do { tmp_name[0] = '\0'; \
- if (name_parse(packet, length, &j, tmp_name, \
- sizeof(tmp_name))<0) \
- goto err; \
- } while (0)
-#define TEST_NAME \
- do { tmp_name[0] = '\0'; \
- cmp_name[0] = '\0'; \
- k = j; \
- if (name_parse(packet, length, &j, tmp_name, \
- sizeof(tmp_name))<0) \
- goto err; \
- if (name_parse(req->request, req->request_len, &k, \
- cmp_name, sizeof(cmp_name))<0) \
- goto err; \
- if (base->global_randomize_case) { \
- if (strcmp(tmp_name, cmp_name) == 0) \
- name_matches = 1; \
- } else { \
- if (evutil_ascii_strcasecmp(tmp_name, cmp_name) == 0) \
- name_matches = 1; \
- } \
- } while (0)
-
- reply.type = req->request_type;
-
- /* skip over each question in the reply */
- for (i = 0; i < questions; ++i) {
- /* the question looks like
- * <label:name><u16:type><u16:class>
- */
- TEST_NAME;
- j += 4;
- if (j >= length) goto err;
- }
-
- if (!name_matches)
- goto err;
-
- /* now we have the answer section which looks like
- * <label:name><u16:type><u16:class><u32:ttl><u16:len><data...>
- */
-
- for (i = 0; i < answers; ++i) {
- u16 type, class;
-
- SKIP_NAME;
- GET16(type);
- GET16(class);
- GET32(ttl);
- GET16(datalength);
-
- if (type == TYPE_A && class == CLASS_INET) {
- int addrcount, addrtocopy;
- if (req->request_type != TYPE_A) {
- j += datalength; continue;
- }
- if ((datalength & 3) != 0) /* not an even number of As. */
- goto err;
- addrcount = datalength >> 2;
- addrtocopy = MIN(MAX_V4_ADDRS - reply.data.a.addrcount, (unsigned)addrcount);
-
- ttl_r = MIN(ttl_r, ttl);
- /* we only bother with the first four addresses. */
- if (j + 4*addrtocopy > length) goto err;
- memcpy(&reply.data.a.addresses[reply.data.a.addrcount],
- packet + j, 4*addrtocopy);
- j += 4*addrtocopy;
- reply.data.a.addrcount += addrtocopy;
- reply.have_answer = 1;
- if (reply.data.a.addrcount == MAX_V4_ADDRS) break;
- } else if (type == TYPE_PTR && class == CLASS_INET) {
- if (req->request_type != TYPE_PTR) {
- j += datalength; continue;
- }
- if (name_parse(packet, length, &j, reply.data.ptr.name,
- sizeof(reply.data.ptr.name))<0)
- goto err;
- ttl_r = MIN(ttl_r, ttl);
- reply.have_answer = 1;
- break;
- } else if (type == TYPE_CNAME) {
- char cname[HOST_NAME_MAX];
- if (!req->put_cname_in_ptr || *req->put_cname_in_ptr) {
- j += datalength; continue;
- }
- if (name_parse(packet, length, &j, cname,
- sizeof(cname))<0)
- goto err;
- *req->put_cname_in_ptr = mm_strdup(cname);
- } else if (type == TYPE_AAAA && class == CLASS_INET) {
- int addrcount, addrtocopy;
- if (req->request_type != TYPE_AAAA) {
- j += datalength; continue;
- }
- if ((datalength & 15) != 0) /* not an even number of AAAAs. */
- goto err;
- addrcount = datalength >> 4; /* each address is 16 bytes long */
- addrtocopy = MIN(MAX_V6_ADDRS - reply.data.aaaa.addrcount, (unsigned)addrcount);
- ttl_r = MIN(ttl_r, ttl);
-
- /* we only bother with the first four addresses. */
- if (j + 16*addrtocopy > length) goto err;
- memcpy(&reply.data.aaaa.addresses[reply.data.aaaa.addrcount],
- packet + j, 16*addrtocopy);
- reply.data.aaaa.addrcount += addrtocopy;
- j += 16*addrtocopy;
- reply.have_answer = 1;
- if (reply.data.aaaa.addrcount == MAX_V6_ADDRS) break;
- } else {
- /* skip over any other type of resource */
- j += datalength;
- }
- }
-
- reply_handle(req, flags, ttl_r, &reply);
- return 0;
- err:
- if (req)
- reply_handle(req, flags, 0, NULL);
- return -1;
-}
-
-/* Parse a raw request (packet,length) sent to a nameserver port (port) from */
-/* a DNS client (addr,addrlen), and if it's well-formed, call the corresponding */
-/* callback. */
-static int
-request_parse(u8 *packet, int length, struct evdns_server_port *port, struct sockaddr *addr, ev_socklen_t addrlen)
-{
- int j = 0; /* index into packet */
- u16 _t; /* used by the macros */
- char tmp_name[256]; /* used by the macros */
-
- int i;
- u16 trans_id, flags, questions, answers, authority, additional;
- struct server_request *server_req = NULL;
-
- ASSERT_LOCKED(port);
-
- /* Get the header fields */
- GET16(trans_id);
- GET16(flags);
- GET16(questions);
- GET16(answers);
- GET16(authority);
- GET16(additional);
- (void)answers;
- (void)additional;
- (void)authority;
-
- if (flags & 0x8000) return -1; /* Must not be an answer. */
- flags &= 0x0110; /* Only RD and CD get preserved. */
-
- server_req = mm_malloc(sizeof(struct server_request));
- if (server_req == NULL) return -1;
- memset(server_req, 0, sizeof(struct server_request));
-
- server_req->trans_id = trans_id;
- memcpy(&server_req->addr, addr, addrlen);
- server_req->addrlen = addrlen;
-
- server_req->base.flags = flags;
- server_req->base.nquestions = 0;
- server_req->base.questions = mm_calloc(sizeof(struct evdns_server_question *), questions);
- if (server_req->base.questions == NULL)
- goto err;
-
- for (i = 0; i < questions; ++i) {
- u16 type, class;
- struct evdns_server_question *q;
- int namelen;
- if (name_parse(packet, length, &j, tmp_name, sizeof(tmp_name))<0)
- goto err;
- GET16(type);
- GET16(class);
- namelen = (int)strlen(tmp_name);
- q = mm_malloc(sizeof(struct evdns_server_question) + namelen);
- if (!q)
- goto err;
- q->type = type;
- q->dns_question_class = class;
- memcpy(q->name, tmp_name, namelen+1);
- server_req->base.questions[server_req->base.nquestions++] = q;
- }
-
- /* Ignore answers, authority, and additional. */
-
- server_req->port = port;
- port->refcnt++;
-
- /* Only standard queries are supported. */
- if (flags & 0x7800) {
- evdns_server_request_respond(&(server_req->base), DNS_ERR_NOTIMPL);
- return -1;
- }
-
- port->user_callback(&(server_req->base), port->user_data);
-
- return 0;
-err:
- if (server_req) {
- if (server_req->base.questions) {
- for (i = 0; i < server_req->base.nquestions; ++i)
- mm_free(server_req->base.questions[i]);
- mm_free(server_req->base.questions);
- }
- mm_free(server_req);
- }
- return -1;
-
-#undef SKIP_NAME
-#undef GET32
-#undef GET16
-#undef GET8
-}
-
-
-void
-evdns_set_transaction_id_fn(ev_uint16_t (*fn)(void))
-{
-}
-
-void
-evdns_set_random_bytes_fn(void (*fn)(char *, size_t))
-{
-}
-
-/* Try to choose a strong transaction id which isn't already in flight */
-static u16
-transaction_id_pick(struct evdns_base *base) {
- ASSERT_LOCKED(base);
- for (;;) {
- u16 trans_id;
- evutil_secure_rng_get_bytes(&trans_id, sizeof(trans_id));
-
- if (trans_id == 0xffff) continue;
- /* now check to see if that id is already inflight */
- if (request_find_from_trans_id(base, trans_id) == NULL)
- return trans_id;
- }
-}
-
-/* choose a namesever to use. This function will try to ignore */
-/* nameservers which we think are down and load balance across the rest */
-/* by updating the server_head global each time. */
-static struct nameserver *
-nameserver_pick(struct evdns_base *base) {
- struct nameserver *started_at = base->server_head, *picked;
- ASSERT_LOCKED(base);
- if (!base->server_head) return NULL;
-
- /* if we don't have any good nameservers then there's no */
- /* point in trying to find one. */
- if (!base->global_good_nameservers) {
- base->server_head = base->server_head->next;
- return base->server_head;
- }
-
- /* remember that nameservers are in a circular list */
- for (;;) {
- if (base->server_head->state) {
- /* we think this server is currently good */
- picked = base->server_head;
- base->server_head = base->server_head->next;
- return picked;
- }
-
- base->server_head = base->server_head->next;
- if (base->server_head == started_at) {
- /* all the nameservers seem to be down */
- /* so we just return this one and hope for the */
- /* best */
- EVUTIL_ASSERT(base->global_good_nameservers == 0);
- picked = base->server_head;
- base->server_head = base->server_head->next;
- return picked;
- }
- }
-}
-
-/* this is called when a namesever socket is ready for reading */
-static void
-nameserver_read(struct nameserver *ns) {
- struct sockaddr_storage ss;
- ev_socklen_t addrlen = sizeof(ss);
- u8 packet[1500];
- char addrbuf[128];
- ASSERT_LOCKED(ns->base);
-
- for (;;) {
- const int r = recvfrom(ns->socket, (void*)packet,
- sizeof(packet), 0,
- (struct sockaddr*)&ss, &addrlen);
- if (r < 0) {
- int err = evutil_socket_geterror(ns->socket);
- if (EVUTIL_ERR_RW_RETRIABLE(err))
- return;
- nameserver_failed(ns,
- evutil_socket_error_to_string(err));
- return;
- }
- if (evutil_sockaddr_cmp((struct sockaddr*)&ss,
- (struct sockaddr*)&ns->address, 0)) {
- log(EVDNS_LOG_WARN, "Address mismatch on received "
- "DNS packet. Apparent source was %s",
- evutil_format_sockaddr_port(
- (struct sockaddr *)&ss,
- addrbuf, sizeof(addrbuf)));
- return;
- }
-
- ns->timedout = 0;
- reply_parse(ns->base, packet, r);
- }
-}
-
-/* Read a packet from a DNS client on a server port s, parse it, and */
-/* act accordingly. */
-static void
-server_port_read(struct evdns_server_port *s) {
- u8 packet[1500];
- struct sockaddr_storage addr;
- ev_socklen_t addrlen;
- int r;
- ASSERT_LOCKED(s);
-
- for (;;) {
- addrlen = sizeof(struct sockaddr_storage);
- r = recvfrom(s->socket, (void*)packet, sizeof(packet), 0,
- (struct sockaddr*) &addr, &addrlen);
- if (r < 0) {
- int err = evutil_socket_geterror(s->socket);
- if (EVUTIL_ERR_RW_RETRIABLE(err))
- return;
- log(EVDNS_LOG_WARN,
- "Error %s (%d) while reading request.",
- evutil_socket_error_to_string(err), err);
- return;
- }
- request_parse(packet, r, s, (struct sockaddr*) &addr, addrlen);
- }
-}
-
-/* Try to write all pending replies on a given DNS server port. */
-static void
-server_port_flush(struct evdns_server_port *port)
-{
- struct server_request *req = port->pending_replies;
- ASSERT_LOCKED(port);
- while (req) {
- int r = sendto(port->socket, req->response, (int)req->response_len, 0,
- (struct sockaddr*) &req->addr, (ev_socklen_t)req->addrlen);
- if (r < 0) {
- int err = evutil_socket_geterror(port->socket);
- if (EVUTIL_ERR_RW_RETRIABLE(err))
- return;
- log(EVDNS_LOG_WARN, "Error %s (%d) while writing response to port; dropping", evutil_socket_error_to_string(err), err);
- }
- if (server_request_free(req)) {
- /* we released the last reference to req->port. */
- return;
- } else {
- EVUTIL_ASSERT(req != port->pending_replies);
- req = port->pending_replies;
- }
- }
-
- /* We have no more pending requests; stop listening for 'writeable' events. */
- (void) event_del(&port->event);
- event_assign(&port->event, port->event_base,
- port->socket, EV_READ | EV_PERSIST,
- server_port_ready_callback, port);
-
- if (event_add(&port->event, NULL) < 0) {
- log(EVDNS_LOG_WARN, "Error from libevent when adding event for DNS server.");
- /* ???? Do more? */
- }
-}
-
-/* set if we are waiting for the ability to write to this server. */
-/* if waiting is true then we ask libevent for EV_WRITE events, otherwise */
-/* we stop these events. */
-static void
-nameserver_write_waiting(struct nameserver *ns, char waiting) {
- ASSERT_LOCKED(ns->base);
- if (ns->write_waiting == waiting) return;
-
- ns->write_waiting = waiting;
- (void) event_del(&ns->event);
- event_assign(&ns->event, ns->base->event_base,
- ns->socket, EV_READ | (waiting ? EV_WRITE : 0) | EV_PERSIST,
- nameserver_ready_callback, ns);
- if (event_add(&ns->event, NULL) < 0) {
- char addrbuf[128];
- log(EVDNS_LOG_WARN, "Error from libevent when adding event for %s",
- evutil_format_sockaddr_port(
- (struct sockaddr *)&ns->address,
- addrbuf, sizeof(addrbuf)));
- /* ???? Do more? */
- }
-}
-
-/* a callback function. Called by libevent when the kernel says that */
-/* a nameserver socket is ready for writing or reading */
-static void
-nameserver_ready_callback(evutil_socket_t fd, short events, void *arg) {
- struct nameserver *ns = (struct nameserver *) arg;
- (void)fd;
-
- EVDNS_LOCK(ns->base);
- if (events & EV_WRITE) {
- ns->choked = 0;
- if (!evdns_transmit(ns->base)) {
- nameserver_write_waiting(ns, 0);
- }
- }
- if (events & EV_READ) {
- nameserver_read(ns);
- }
- EVDNS_UNLOCK(ns->base);
-}
-
-/* a callback function. Called by libevent when the kernel says that */
-/* a server socket is ready for writing or reading. */
-static void
-server_port_ready_callback(evutil_socket_t fd, short events, void *arg) {
- struct evdns_server_port *port = (struct evdns_server_port *) arg;
- (void) fd;
-
- EVDNS_LOCK(port);
- if (events & EV_WRITE) {
- port->choked = 0;
- server_port_flush(port);
- }
- if (events & EV_READ) {
- server_port_read(port);
- }
- EVDNS_UNLOCK(port);
-}
-
-/* This is an inefficient representation; only use it via the dnslabel_table_*
- * functions, so that is can be safely replaced with something smarter later. */
-#define MAX_LABELS 128
-/* Structures used to implement name compression */
-struct dnslabel_entry { char *v; off_t pos; };
-struct dnslabel_table {
- int n_labels; /* number of current entries */
- /* map from name to position in message */
- struct dnslabel_entry labels[MAX_LABELS];
-};
-
-/* Initialize dnslabel_table. */
-static void
-dnslabel_table_init(struct dnslabel_table *table)
-{
- table->n_labels = 0;
-}
-
-/* Free all storage held by table, but not the table itself. */
-static void
-dnslabel_clear(struct dnslabel_table *table)
-{
- int i;
- for (i = 0; i < table->n_labels; ++i)
- mm_free(table->labels[i].v);
- table->n_labels = 0;
-}
-
-/* return the position of the label in the current message, or -1 if the label */
-/* hasn't been used yet. */
-static int
-dnslabel_table_get_pos(const struct dnslabel_table *table, const char *label)
-{
- int i;
- for (i = 0; i < table->n_labels; ++i) {
- if (!strcmp(label, table->labels[i].v))
- return table->labels[i].pos;
- }
- return -1;
-}
-
-/* remember that we've used the label at position pos */
-static int
-dnslabel_table_add(struct dnslabel_table *table, const char *label, off_t pos)
-{
- char *v;
- int p;
- if (table->n_labels == MAX_LABELS)
- return (-1);
- v = mm_strdup(label);
- if (v == NULL)
- return (-1);
- p = table->n_labels++;
- table->labels[p].v = v;
- table->labels[p].pos = pos;
-
- return (0);
-}
-
-/* Converts a string to a length-prefixed set of DNS labels, starting */
-/* at buf[j]. name and buf must not overlap. name_len should be the length */
-/* of name. table is optional, and is used for compression. */
-/* */
-/* Input: abc.def */
-/* Output: <3>abc<3>def<0> */
-/* */
-/* Returns the first index after the encoded name, or negative on error. */
-/* -1 label was > 63 bytes */
-/* -2 name too long to fit in buffer. */
-/* */
-static off_t
-dnsname_to_labels(u8 *const buf, size_t buf_len, off_t j,
- const char *name, const size_t name_len,
- struct dnslabel_table *table) {
- const char *end = name + name_len;
- int ref = 0;
- u16 _t;
-
-#define APPEND16(x) do { \
- if (j + 2 > (off_t)buf_len) \
- goto overflow; \
- _t = htons(x); \
- memcpy(buf + j, &_t, 2); \
- j += 2; \
- } while (0)
-#define APPEND32(x) do { \
- if (j + 4 > (off_t)buf_len) \
- goto overflow; \
- _t32 = htonl(x); \
- memcpy(buf + j, &_t32, 4); \
- j += 4; \
- } while (0)
-
- if (name_len > 255) return -2;
-
- for (;;) {
- const char *const start = name;
- if (table && (ref = dnslabel_table_get_pos(table, name)) >= 0) {
- APPEND16(ref | 0xc000);
- return j;
- }
- name = strchr(name, '.');
- if (!name) {
- const size_t label_len = end - start;
- if (label_len > 63) return -1;
- if ((size_t)(j+label_len+1) > buf_len) return -2;
- if (table) dnslabel_table_add(table, start, j);
- buf[j++] = (ev_uint8_t)label_len;
-
- memcpy(buf + j, start, label_len);
- j += (int) label_len;
- break;
- } else {
- /* append length of the label. */
- const size_t label_len = name - start;
- if (label_len > 63) return -1;
- if ((size_t)(j+label_len+1) > buf_len) return -2;
- if (table) dnslabel_table_add(table, start, j);
- buf[j++] = (ev_uint8_t)label_len;
-
- memcpy(buf + j, start, label_len);
- j += (int) label_len;
- /* hop over the '.' */
- name++;
- }
- }
-
- /* the labels must be terminated by a 0. */
- /* It's possible that the name ended in a . */
- /* in which case the zero is already there */
- if (!j || buf[j-1]) buf[j++] = 0;
- return j;
- overflow:
- return (-2);
-}
-
-/* Finds the length of a dns request for a DNS name of the given */
-/* length. The actual request may be smaller than the value returned */
-/* here */
-static size_t
-evdns_request_len(const size_t name_len) {
- return 96 + /* length of the DNS standard header */
- name_len + 2 +
- 4; /* space for the resource type */
-}
-
-/* build a dns request packet into buf. buf should be at least as long */
-/* as evdns_request_len told you it should be. */
-/* */
-/* Returns the amount of space used. Negative on error. */
-static int
-evdns_request_data_build(const char *const name, const size_t name_len,
- const u16 trans_id, const u16 type, const u16 class,
- u8 *const buf, size_t buf_len) {
- off_t j = 0; /* current offset into buf */
- u16 _t; /* used by the macros */
-
- APPEND16(trans_id);
- APPEND16(0x0100); /* standard query, recusion needed */
- APPEND16(1); /* one question */
- APPEND16(0); /* no answers */
- APPEND16(0); /* no authority */
- APPEND16(0); /* no additional */
-
- j = dnsname_to_labels(buf, buf_len, j, name, name_len, NULL);
- if (j < 0) {
- return (int)j;
- }
-
- APPEND16(type);
- APPEND16(class);
-
- return (int)j;
- overflow:
- return (-1);
-}
-
-/* exported function */
-struct evdns_server_port *
-evdns_add_server_port_with_base(struct event_base *base, evutil_socket_t socket, int flags, evdns_request_callback_fn_type cb, void *user_data)
-{
- struct evdns_server_port *port;
- if (flags)
- return NULL; /* flags not yet implemented */
- if (!(port = mm_malloc(sizeof(struct evdns_server_port))))
- return NULL;
- memset(port, 0, sizeof(struct evdns_server_port));
-
-
- port->socket = socket;
- port->refcnt = 1;
- port->choked = 0;
- port->closing = 0;
- port->user_callback = cb;
- port->user_data = user_data;
- port->pending_replies = NULL;
- port->event_base = base;
-
- event_assign(&port->event, port->event_base,
- port->socket, EV_READ | EV_PERSIST,
- server_port_ready_callback, port);
- if (event_add(&port->event, NULL) < 0) {
- mm_free(port);
- return NULL;
- }
- EVTHREAD_ALLOC_LOCK(port->lock, EVTHREAD_LOCKTYPE_RECURSIVE);
- return port;
-}
-
-struct evdns_server_port *
-evdns_add_server_port(evutil_socket_t socket, int flags, evdns_request_callback_fn_type cb, void *user_data)
-{
- return evdns_add_server_port_with_base(NULL, socket, flags, cb, user_data);
-}
-
-/* exported function */
-void
-evdns_close_server_port(struct evdns_server_port *port)
-{
- EVDNS_LOCK(port);
- if (--port->refcnt == 0) {
- EVDNS_UNLOCK(port);
- server_port_free(port);
- } else {
- port->closing = 1;
- }
-}
-
-/* exported function */
-int
-evdns_server_request_add_reply(struct evdns_server_request *_req, int section, const char *name, int type, int class, int ttl, int datalen, int is_name, const char *data)
-{
- struct server_request *req = TO_SERVER_REQUEST(_req);
- struct server_reply_item **itemp, *item;
- int *countp;
- int result = -1;
-
- EVDNS_LOCK(req->port);
- if (req->response) /* have we already answered? */
- goto done;
-
- switch (section) {
- case EVDNS_ANSWER_SECTION:
- itemp = &req->answer;
- countp = &req->n_answer;
- break;
- case EVDNS_AUTHORITY_SECTION:
- itemp = &req->authority;
- countp = &req->n_authority;
- break;
- case EVDNS_ADDITIONAL_SECTION:
- itemp = &req->additional;
- countp = &req->n_additional;
- break;
- default:
- goto done;
- }
- while (*itemp) {
- itemp = &((*itemp)->next);
- }
- item = mm_malloc(sizeof(struct server_reply_item));
- if (!item)
- goto done;
- item->next = NULL;
- if (!(item->name = mm_strdup(name))) {
- mm_free(item);
- goto done;
- }
- item->type = type;
- item->dns_question_class = class;
- item->ttl = ttl;
- item->is_name = is_name != 0;
- item->datalen = 0;
- item->data = NULL;
- if (data) {
- if (item->is_name) {
- if (!(item->data = mm_strdup(data))) {
- mm_free(item->name);
- mm_free(item);
- goto done;
- }
- item->datalen = (u16)-1;
- } else {
- if (!(item->data = mm_malloc(datalen))) {
- mm_free(item->name);
- mm_free(item);
- goto done;
- }
- item->datalen = datalen;
- memcpy(item->data, data, datalen);
- }
- }
-
- *itemp = item;
- ++(*countp);
- result = 0;
-done:
- EVDNS_UNLOCK(req->port);
- return result;
-}
-
-/* exported function */
-int
-evdns_server_request_add_a_reply(struct evdns_server_request *req, const char *name, int n, const void *addrs, int ttl)
-{
- return evdns_server_request_add_reply(
- req, EVDNS_ANSWER_SECTION, name, TYPE_A, CLASS_INET,
- ttl, n*4, 0, addrs);
-}
-
-/* exported function */
-int
-evdns_server_request_add_aaaa_reply(struct evdns_server_request *req, const char *name, int n, const void *addrs, int ttl)
-{
- return evdns_server_request_add_reply(
- req, EVDNS_ANSWER_SECTION, name, TYPE_AAAA, CLASS_INET,
- ttl, n*16, 0, addrs);
-}
-
-/* exported function */
-int
-evdns_server_request_add_ptr_reply(struct evdns_server_request *req, struct in_addr *in, const char *inaddr_name, const char *hostname, int ttl)
-{
- u32 a;
- char buf[32];
- if (in && inaddr_name)
- return -1;
- else if (!in && !inaddr_name)
- return -1;
- if (in) {
- a = ntohl(in->s_addr);
- evutil_snprintf(buf, sizeof(buf), "%d.%d.%d.%d.in-addr.arpa",
- (int)(u8)((a )&0xff),
- (int)(u8)((a>>8 )&0xff),
- (int)(u8)((a>>16)&0xff),
- (int)(u8)((a>>24)&0xff));
- inaddr_name = buf;
- }
- return evdns_server_request_add_reply(
- req, EVDNS_ANSWER_SECTION, inaddr_name, TYPE_PTR, CLASS_INET,
- ttl, -1, 1, hostname);
-}
-
-/* exported function */
-int
-evdns_server_request_add_cname_reply(struct evdns_server_request *req, const char *name, const char *cname, int ttl)
-{
- return evdns_server_request_add_reply(
- req, EVDNS_ANSWER_SECTION, name, TYPE_CNAME, CLASS_INET,
- ttl, -1, 1, cname);
-}
-
-/* exported function */
-void
-evdns_server_request_set_flags(struct evdns_server_request *exreq, int flags)
-{
- struct server_request *req = TO_SERVER_REQUEST(exreq);
- req->base.flags &= ~(EVDNS_FLAGS_AA|EVDNS_FLAGS_RD);
- req->base.flags |= flags;
-}
-
-static int
-evdns_server_request_format_response(struct server_request *req, int err)
-{
- unsigned char buf[1500];
- size_t buf_len = sizeof(buf);
- off_t j = 0, r;
- u16 _t;
- u32 _t32;
- int i;
- u16 flags;
- struct dnslabel_table table;
-
- if (err < 0 || err > 15) return -1;
-
- /* Set response bit and error code; copy OPCODE and RD fields from
- * question; copy RA and AA if set by caller. */
- flags = req->base.flags;
- flags |= (0x8000 | err);
-
- dnslabel_table_init(&table);
- APPEND16(req->trans_id);
- APPEND16(flags);
- APPEND16(req->base.nquestions);
- APPEND16(req->n_answer);
- APPEND16(req->n_authority);
- APPEND16(req->n_additional);
-
- /* Add questions. */
- for (i=0; i < req->base.nquestions; ++i) {
- const char *s = req->base.questions[i]->name;
- j = dnsname_to_labels(buf, buf_len, j, s, strlen(s), &table);
- if (j < 0) {
- dnslabel_clear(&table);
- return (int) j;
- }
- APPEND16(req->base.questions[i]->type);
- APPEND16(req->base.questions[i]->dns_question_class);
- }
-
- /* Add answer, authority, and additional sections. */
- for (i=0; i<3; ++i) {
- struct server_reply_item *item;
- if (i==0)
- item = req->answer;
- else if (i==1)
- item = req->authority;
- else
- item = req->additional;
- while (item) {
- r = dnsname_to_labels(buf, buf_len, j, item->name, strlen(item->name), &table);
- if (r < 0)
- goto overflow;
- j = r;
-
- APPEND16(item->type);
- APPEND16(item->dns_question_class);
- APPEND32(item->ttl);
- if (item->is_name) {
- off_t len_idx = j, name_start;
- j += 2;
- name_start = j;
- r = dnsname_to_labels(buf, buf_len, j, item->data, strlen(item->data), &table);
- if (r < 0)
- goto overflow;
- j = r;
- _t = htons( (short) (j-name_start) );
- memcpy(buf+len_idx, &_t, 2);
- } else {
- APPEND16(item->datalen);
- if (j+item->datalen > (off_t)buf_len)
- goto overflow;
- memcpy(buf+j, item->data, item->datalen);
- j += item->datalen;
- }
- item = item->next;
- }
- }
-
- if (j > 512) {
-overflow:
- j = 512;
- buf[2] |= 0x02; /* set the truncated bit. */
- }
-
- req->response_len = j;
-
- if (!(req->response = mm_malloc(req->response_len))) {
- server_request_free_answers(req);
- dnslabel_clear(&table);
- return (-1);
- }
- memcpy(req->response, buf, req->response_len);
- server_request_free_answers(req);
- dnslabel_clear(&table);
- return (0);
-}
-
-/* exported function */
-int
-evdns_server_request_respond(struct evdns_server_request *_req, int err)
-{
- struct server_request *req = TO_SERVER_REQUEST(_req);
- struct evdns_server_port *port = req->port;
- int r = -1;
-
- EVDNS_LOCK(port);
- if (!req->response) {
- if ((r = evdns_server_request_format_response(req, err))<0)
- goto done;
- }
-
- r = sendto(port->socket, req->response, (int)req->response_len, 0,
- (struct sockaddr*) &req->addr, (ev_socklen_t)req->addrlen);
- if (r<0) {
- int sock_err = evutil_socket_geterror(port->socket);
- if (EVUTIL_ERR_RW_RETRIABLE(sock_err))
- goto done;
-
- if (port->pending_replies) {
- req->prev_pending = port->pending_replies->prev_pending;
- req->next_pending = port->pending_replies;
- req->prev_pending->next_pending =
- req->next_pending->prev_pending = req;
- } else {
- req->prev_pending = req->next_pending = req;
- port->pending_replies = req;
- port->choked = 1;
-
- (void) event_del(&port->event);
- event_assign(&port->event, port->event_base, port->socket, (port->closing?0:EV_READ) | EV_WRITE | EV_PERSIST, server_port_ready_callback, port);
-
- if (event_add(&port->event, NULL) < 0) {
- log(EVDNS_LOG_WARN, "Error from libevent when adding event for DNS server");
- }
-
- }
-
- r = 1;
- goto done;
- }
- if (server_request_free(req)) {
- r = 0;
- goto done;
- }
-
- if (port->pending_replies)
- server_port_flush(port);
-
- r = 0;
-done:
- EVDNS_UNLOCK(port);
- return r;
-}
-
-/* Free all storage held by RRs in req. */
-static void
-server_request_free_answers(struct server_request *req)
-{
- struct server_reply_item *victim, *next, **list;
- int i;
- for (i = 0; i < 3; ++i) {
- if (i==0)
- list = &req->answer;
- else if (i==1)
- list = &req->authority;
- else
- list = &req->additional;
-
- victim = *list;
- while (victim) {
- next = victim->next;
- mm_free(victim->name);
- if (victim->data)
- mm_free(victim->data);
- mm_free(victim);
- victim = next;
- }
- *list = NULL;
- }
-}
-
-/* Free all storage held by req, and remove links to it. */
-/* return true iff we just wound up freeing the server_port. */
-static int
-server_request_free(struct server_request *req)
-{
- int i, rc=1, lock=0;
- if (req->base.questions) {
- for (i = 0; i < req->base.nquestions; ++i)
- mm_free(req->base.questions[i]);
- mm_free(req->base.questions);
- }
-
- if (req->port) {
- EVDNS_LOCK(req->port);
- lock=1;
- if (req->port->pending_replies == req) {
- if (req->next_pending && req->next_pending != req)
- req->port->pending_replies = req->next_pending;
- else
- req->port->pending_replies = NULL;
- }
- rc = --req->port->refcnt;
- }
-
- if (req->response) {
- mm_free(req->response);
- }
-
- server_request_free_answers(req);
-
- if (req->next_pending && req->next_pending != req) {
- req->next_pending->prev_pending = req->prev_pending;
- req->prev_pending->next_pending = req->next_pending;
- }
-
- if (rc == 0) {
- EVDNS_UNLOCK(req->port); /* ????? nickm */
- server_port_free(req->port);
- mm_free(req);
- return (1);
- }
- if (lock)
- EVDNS_UNLOCK(req->port);
- mm_free(req);
- return (0);
-}
-
-/* Free all storage held by an evdns_server_port. Only called when */
-static void
-server_port_free(struct evdns_server_port *port)
-{
- EVUTIL_ASSERT(port);
- EVUTIL_ASSERT(!port->refcnt);
- EVUTIL_ASSERT(!port->pending_replies);
- if (port->socket > 0) {
- evutil_closesocket(port->socket);
- port->socket = -1;
- }
- (void) event_del(&port->event);
- event_debug_unassign(&port->event);
- EVTHREAD_FREE_LOCK(port->lock, EVTHREAD_LOCKTYPE_RECURSIVE);
- mm_free(port);
-}
-
-/* exported function */
-int
-evdns_server_request_drop(struct evdns_server_request *_req)
-{
- struct server_request *req = TO_SERVER_REQUEST(_req);
- server_request_free(req);
- return 0;
-}
-
-/* exported function */
-int
-evdns_server_request_get_requesting_addr(struct evdns_server_request *_req, struct sockaddr *sa, int addr_len)
-{
- struct server_request *req = TO_SERVER_REQUEST(_req);
- if (addr_len < (int)req->addrlen)
- return -1;
- memcpy(sa, &(req->addr), req->addrlen);
- return req->addrlen;
-}
-
-#undef APPEND16
-#undef APPEND32
-
-/* this is a libevent callback function which is called when a request */
-/* has timed out. */
-static void
-evdns_request_timeout_callback(evutil_socket_t fd, short events, void *arg) {
- struct request *const req = (struct request *) arg;
-#ifndef _EVENT_DISABLE_THREAD_SUPPORT
- struct evdns_base *base = req->base;
-#endif
- (void) fd;
- (void) events;
-
- log(EVDNS_LOG_DEBUG, "Request %p timed out", arg);
- EVDNS_LOCK(base);
-
- req->ns->timedout++;
- if (req->ns->timedout > req->base->global_max_nameserver_timeout) {
- req->ns->timedout = 0;
- nameserver_failed(req->ns, "request timed out.");
- }
-
- if (req->tx_count >= req->base->global_max_retransmits) {
- /* this request has failed */
- reply_schedule_callback(req, 0, DNS_ERR_TIMEOUT, NULL);
- request_finished(req, &REQ_HEAD(req->base, req->trans_id), 1);
- } else {
- /* retransmit it */
- (void) evtimer_del(&req->timeout_event);
- evdns_request_transmit(req);
- }
- EVDNS_UNLOCK(base);
-}
-
-/* try to send a request to a given server. */
-/* */
-/* return: */
-/* 0 ok */
-/* 1 temporary failure */
-/* 2 other failure */
-static int
-evdns_request_transmit_to(struct request *req, struct nameserver *server) {
- int r;
- ASSERT_LOCKED(req->base);
- ASSERT_VALID_REQUEST(req);
- r = sendto(server->socket, (void*)req->request, req->request_len, 0,
- (struct sockaddr *)&server->address, server->addrlen);
- if (r < 0) {
- int err = evutil_socket_geterror(server->socket);
- if (EVUTIL_ERR_RW_RETRIABLE(err))
- return 1;
- nameserver_failed(req->ns, evutil_socket_error_to_string(err));
- return 2;
- } else if (r != (int)req->request_len) {
- return 1; /* short write */
- } else {
- return 0;
- }
-}
-
-/* try to send a request, updating the fields of the request */
-/* as needed */
-/* */
-/* return: */
-/* 0 ok */
-/* 1 failed */
-static int
-evdns_request_transmit(struct request *req) {
- int retcode = 0, r;
-
- ASSERT_LOCKED(req->base);
- ASSERT_VALID_REQUEST(req);
- /* if we fail to send this packet then this flag marks it */
- /* for evdns_transmit */
- req->transmit_me = 1;
- EVUTIL_ASSERT(req->trans_id != 0xffff);
-
- if (req->ns->choked) {
- /* don't bother trying to write to a socket */
- /* which we have had EAGAIN from */
- return 1;
- }
-
- r = evdns_request_transmit_to(req, req->ns);
- switch (r) {
- case 1:
- /* temp failure */
- req->ns->choked = 1;
- nameserver_write_waiting(req->ns, 1);
- return 1;
- case 2:
- /* failed to transmit the request entirely. */
- retcode = 1;
- /* fall through: we'll set a timeout, which will time out,
- * and make us retransmit the request anyway. */
- default:
- /* all ok */
- log(EVDNS_LOG_DEBUG,
- "Setting timeout for request %p", req);
- if (evtimer_add(&req->timeout_event, &req->base->global_timeout) < 0) {
- log(EVDNS_LOG_WARN,
- "Error from libevent when adding timer for request %p",
- req);
- /* ???? Do more? */
- }
- req->tx_count++;
- req->transmit_me = 0;
- return retcode;
- }
-}
-
-static void
-nameserver_probe_callback(int result, char type, int count, int ttl, void *addresses, void *arg) {
- struct nameserver *const ns = (struct nameserver *) arg;
- (void) type;
- (void) count;
- (void) ttl;
- (void) addresses;
-
- EVDNS_LOCK(ns->base);
- ns->probe_request = NULL;
- if (result == DNS_ERR_CANCEL) {
- /* We canceled this request because the nameserver came up
- * for some other reason. Do not change our opinion about
- * the nameserver. */
- } else if (result == DNS_ERR_NONE || result == DNS_ERR_NOTEXIST) {
- /* this is a good reply */
- nameserver_up(ns);
- } else {
- nameserver_probe_failed(ns);
- }
- EVDNS_UNLOCK(ns->base);
-}
-
-static void
-nameserver_send_probe(struct nameserver *const ns) {
- struct evdns_request *handle;
- struct request *req;
- char addrbuf[128];
- /* here we need to send a probe to a given nameserver */
- /* in the hope that it is up now. */
-
- ASSERT_LOCKED(ns->base);
- log(EVDNS_LOG_DEBUG, "Sending probe to %s",
- evutil_format_sockaddr_port(
- (struct sockaddr *)&ns->address,
- addrbuf, sizeof(addrbuf)));
- handle = mm_calloc(1, sizeof(*handle));
- if (!handle) return;
- req = request_new(ns->base, handle, TYPE_A, "google.com", DNS_QUERY_NO_SEARCH, nameserver_probe_callback, ns);
- if (!req) return;
- ns->probe_request = handle;
- /* we force this into the inflight queue no matter what */
- request_trans_id_set(req, transaction_id_pick(ns->base));
- req->ns = ns;
- request_submit(req);
-}
-
-/* returns: */
-/* 0 didn't try to transmit anything */
-/* 1 tried to transmit something */
-static int
-evdns_transmit(struct evdns_base *base) {
- char did_try_to_transmit = 0;
- int i;
-
- ASSERT_LOCKED(base);
- for (i = 0; i < base->n_req_heads; ++i) {
- if (base->req_heads[i]) {
- struct request *const started_at = base->req_heads[i], *req = started_at;
- /* first transmit all the requests which are currently waiting */
- do {
- if (req->transmit_me) {
- did_try_to_transmit = 1;
- evdns_request_transmit(req);
- }
-
- req = req->next;
- } while (req != started_at);
- }
- }
-
- return did_try_to_transmit;
-}
-
-/* exported function */
-int
-evdns_base_count_nameservers(struct evdns_base *base)
-{
- const struct nameserver *server;
- int n = 0;
-
- EVDNS_LOCK(base);
- server = base->server_head;
- if (!server)
- goto done;
- do {
- ++n;
- server = server->next;
- } while (server != base->server_head);
-done:
- EVDNS_UNLOCK(base);
- return n;
-}
-
-int
-evdns_count_nameservers(void)
-{
- return evdns_base_count_nameservers(current_base);
-}
-
-/* exported function */
-int
-evdns_base_clear_nameservers_and_suspend(struct evdns_base *base)
-{
- struct nameserver *server, *started_at;
- int i;
-
- EVDNS_LOCK(base);
- server = base->server_head;
- started_at = base->server_head;
- if (!server) {
- EVDNS_UNLOCK(base);
- return 0;
- }
- while (1) {
- struct nameserver *next = server->next;
- (void) event_del(&server->event);
- if (evtimer_initialized(&server->timeout_event))
- (void) evtimer_del(&server->timeout_event);
- if (server->socket >= 0)
- evutil_closesocket(server->socket);
- mm_free(server);
- if (next == started_at)
- break;
- server = next;
- }
- base->server_head = NULL;
- base->global_good_nameservers = 0;
-
- for (i = 0; i < base->n_req_heads; ++i) {
- struct request *req, *req_started_at;
- req = req_started_at = base->req_heads[i];
- while (req) {
- struct request *next = req->next;
- req->tx_count = req->reissue_count = 0;
- req->ns = NULL;
- /* ???? What to do about searches? */
- (void) evtimer_del(&req->timeout_event);
- req->trans_id = 0;
- req->transmit_me = 0;
-
- base->global_requests_waiting++;
- evdns_request_insert(req, &base->req_waiting_head);
- /* We want to insert these suspended elements at the front of
- * the waiting queue, since they were pending before any of
- * the waiting entries were added. This is a circular list,
- * so we can just shift the start back by one.*/
- base->req_waiting_head = base->req_waiting_head->prev;
-
- if (next == req_started_at)
- break;
- req = next;
- }
- base->req_heads[i] = NULL;
- }
-
- base->global_requests_inflight = 0;
-
- EVDNS_UNLOCK(base);
- return 0;
-}
-
-int
-evdns_clear_nameservers_and_suspend(void)
-{
- return evdns_base_clear_nameservers_and_suspend(current_base);
-}
-
-
-/* exported function */
-int
-evdns_base_resume(struct evdns_base *base)
-{
- EVDNS_LOCK(base);
- evdns_requests_pump_waiting_queue(base);
- EVDNS_UNLOCK(base);
- return 0;
-}
-
-int
-evdns_resume(void)
-{
- return evdns_base_resume(current_base);
-}
-
-static int
-_evdns_nameserver_add_impl(struct evdns_base *base, const struct sockaddr *address, int addrlen) {
- /* first check to see if we already have this nameserver */
-
- const struct nameserver *server = base->server_head, *const started_at = base->server_head;
- struct nameserver *ns;
- int err = 0;
- char addrbuf[128];
-
- ASSERT_LOCKED(base);
- if (server) {
- do {
- if (!evutil_sockaddr_cmp((struct sockaddr*)&server->address, address, 1)) return 3;
- server = server->next;
- } while (server != started_at);
- }
- if (addrlen > (int)sizeof(ns->address)) {
- log(EVDNS_LOG_DEBUG, "Addrlen %d too long.", (int)addrlen);
- return 2;
- }
-
- ns = (struct nameserver *) mm_malloc(sizeof(struct nameserver));
- if (!ns) return -1;
-
- memset(ns, 0, sizeof(struct nameserver));
- ns->base = base;
-
- evtimer_assign(&ns->timeout_event, ns->base->event_base, nameserver_prod_callback, ns);
-
- ns->socket = socket(address->sa_family, SOCK_DGRAM, 0);
- if (ns->socket < 0) { err = 1; goto out1; }
- evutil_make_socket_closeonexec(ns->socket);
- evutil_make_socket_nonblocking(ns->socket);
-
- if (base->global_outgoing_addrlen &&
- !evutil_sockaddr_is_loopback(address)) {
- if (bind(ns->socket,
- (struct sockaddr*)&base->global_outgoing_address,
- base->global_outgoing_addrlen) < 0) {
- log(EVDNS_LOG_WARN,"Couldn't bind to outgoing address");
- err = 2;
- goto out2;
- }
- }
-
- memcpy(&ns->address, address, addrlen);
- ns->addrlen = addrlen;
- ns->state = 1;
- event_assign(&ns->event, ns->base->event_base, ns->socket, EV_READ | EV_PERSIST, nameserver_ready_callback, ns);
- if (event_add(&ns->event, NULL) < 0) {
- err = 2;
- goto out2;
- }
-
- log(EVDNS_LOG_DEBUG, "Added nameserver %s",
- evutil_format_sockaddr_port(address, addrbuf, sizeof(addrbuf)));
-
- /* insert this nameserver into the list of them */
- if (!base->server_head) {
- ns->next = ns->prev = ns;
- base->server_head = ns;
- } else {
- ns->next = base->server_head->next;
- ns->prev = base->server_head;
- base->server_head->next = ns;
- if (base->server_head->prev == base->server_head) {
- base->server_head->prev = ns;
- }
- }
-
- base->global_good_nameservers++;
-
- return 0;
-
-out2:
- evutil_closesocket(ns->socket);
-out1:
- event_debug_unassign(&ns->event);
- mm_free(ns);
- log(EVDNS_LOG_WARN, "Unable to add nameserver %s: error %d",
- evutil_format_sockaddr_port(address, addrbuf, sizeof(addrbuf)), err);
- return err;
-}
-
-/* exported function */
-int
-evdns_base_nameserver_add(struct evdns_base *base, unsigned long int address)
-{
- struct sockaddr_in sin;
- int res;
- sin.sin_addr.s_addr = address;
- sin.sin_port = htons(53);
- sin.sin_family = AF_INET;
- EVDNS_LOCK(base);
- res = _evdns_nameserver_add_impl(base, (struct sockaddr*)&sin, sizeof(sin));
- EVDNS_UNLOCK(base);
- return res;
-}
-
-int
-evdns_nameserver_add(unsigned long int address) {
- if (!current_base)
- current_base = evdns_base_new(NULL, 0);
- return evdns_base_nameserver_add(current_base, address);
-}
-
-static void
-sockaddr_setport(struct sockaddr *sa, ev_uint16_t port)
-{
- if (sa->sa_family == AF_INET) {
- ((struct sockaddr_in *)sa)->sin_port = htons(port);
- } else if (sa->sa_family == AF_INET6) {
- ((struct sockaddr_in6 *)sa)->sin6_port = htons(port);
- }
-}
-
-static ev_uint16_t
-sockaddr_getport(struct sockaddr *sa)
-{
- if (sa->sa_family == AF_INET) {
- return ntohs(((struct sockaddr_in *)sa)->sin_port);
- } else if (sa->sa_family == AF_INET6) {
- return ntohs(((struct sockaddr_in6 *)sa)->sin6_port);
- } else {
- return 0;
- }
-}
-
-/* exported function */
-int
-evdns_base_nameserver_ip_add(struct evdns_base *base, const char *ip_as_string) {
- struct sockaddr_storage ss;
- struct sockaddr *sa;
- int len = sizeof(ss);
- int res;
- if (evutil_parse_sockaddr_port(ip_as_string, (struct sockaddr *)&ss,
- &len)) {
- log(EVDNS_LOG_WARN, "Unable to parse nameserver address %s",
- ip_as_string);
- return 4;
- }
- sa = (struct sockaddr *) &ss;
- if (sockaddr_getport(sa) == 0)
- sockaddr_setport(sa, 53);
-
- EVDNS_LOCK(base);
- res = _evdns_nameserver_add_impl(base, sa, len);
- EVDNS_UNLOCK(base);
- return res;
-}
-
-int
-evdns_nameserver_ip_add(const char *ip_as_string) {
- if (!current_base)
- current_base = evdns_base_new(NULL, 0);
- return evdns_base_nameserver_ip_add(current_base, ip_as_string);
-}
-
-int
-evdns_base_nameserver_sockaddr_add(struct evdns_base *base,
- const struct sockaddr *sa, ev_socklen_t len, unsigned flags)
-{
- int res;
- EVUTIL_ASSERT(base);
- EVDNS_LOCK(base);
- res = _evdns_nameserver_add_impl(base, sa, len);
- EVDNS_UNLOCK(base);
- return res;
-}
-
-/* remove from the queue */
-static void
-evdns_request_remove(struct request *req, struct request **head)
-{
- ASSERT_LOCKED(req->base);
- ASSERT_VALID_REQUEST(req);
-
-#if 0
- {
- struct request *ptr;
- int found = 0;
- EVUTIL_ASSERT(*head != NULL);
-
- ptr = *head;
- do {
- if (ptr == req) {
- found = 1;
- break;
- }
- ptr = ptr->next;
- } while (ptr != *head);
- EVUTIL_ASSERT(found);
-
- EVUTIL_ASSERT(req->next);
- }
-#endif
-
- if (req->next == req) {
- /* only item in the list */
- *head = NULL;
- } else {
- req->next->prev = req->prev;
- req->prev->next = req->next;
- if (*head == req) *head = req->next;
- }
- req->next = req->prev = NULL;
-}
-
-/* insert into the tail of the queue */
-static void
-evdns_request_insert(struct request *req, struct request **head) {
- ASSERT_LOCKED(req->base);
- ASSERT_VALID_REQUEST(req);
- if (!*head) {
- *head = req;
- req->next = req->prev = req;
- return;
- }
-
- req->prev = (*head)->prev;
- req->prev->next = req;
- req->next = *head;
- (*head)->prev = req;
-}
-
-static int
-string_num_dots(const char *s) {
- int count = 0;
- while ((s = strchr(s, '.'))) {
- s++;
- count++;
- }
- return count;
-}
-
-static struct request *
-request_new(struct evdns_base *base, struct evdns_request *handle, int type,
- const char *name, int flags, evdns_callback_type callback,
- void *user_ptr) {
-
- const char issuing_now =
- (base->global_requests_inflight < base->global_max_requests_inflight) ? 1 : 0;
-
- const size_t name_len = strlen(name);
- const size_t request_max_len = evdns_request_len(name_len);
- const u16 trans_id = issuing_now ? transaction_id_pick(base) : 0xffff;
- /* the request data is alloced in a single block with the header */
- struct request *const req =
- mm_malloc(sizeof(struct request) + request_max_len);
- int rlen;
- char namebuf[256];
- (void) flags;
-
- ASSERT_LOCKED(base);
-
- if (!req) return NULL;
-
- if (name_len >= sizeof(namebuf)) {
- mm_free(req);
- return NULL;
- }
-
- memset(req, 0, sizeof(struct request));
- req->base = base;
-
- evtimer_assign(&req->timeout_event, req->base->event_base, evdns_request_timeout_callback, req);
-
- if (base->global_randomize_case) {
- unsigned i;
- char randbits[(sizeof(namebuf)+7)/8];
- strlcpy(namebuf, name, sizeof(namebuf));
- evutil_secure_rng_get_bytes(randbits, (name_len+7)/8);
- for (i = 0; i < name_len; ++i) {
- if (EVUTIL_ISALPHA(namebuf[i])) {
- if ((randbits[i >> 3] & (1<<(i & 7))))
- namebuf[i] |= 0x20;
- else
- namebuf[i] &= ~0x20;
- }
- }
- name = namebuf;
- }
-
- /* request data lives just after the header */
- req->request = ((u8 *) req) + sizeof(struct request);
- /* denotes that the request data shouldn't be free()ed */
- req->request_appended = 1;
- rlen = evdns_request_data_build(name, name_len, trans_id,
- type, CLASS_INET, req->request, request_max_len);
- if (rlen < 0)
- goto err1;
-
- req->request_len = rlen;
- req->trans_id = trans_id;
- req->tx_count = 0;
- req->request_type = type;
- req->user_pointer = user_ptr;
- req->user_callback = callback;
- req->ns = issuing_now ? nameserver_pick(base) : NULL;
- req->next = req->prev = NULL;
- req->handle = handle;
- if (handle) {
- handle->current_req = req;
- handle->base = base;
- }
-
- return req;
-err1:
- mm_free(req);
- return NULL;
-}
-
-static void
-request_submit(struct request *const req) {
- struct evdns_base *base = req->base;
- ASSERT_LOCKED(base);
- ASSERT_VALID_REQUEST(req);
- if (req->ns) {
- /* if it has a nameserver assigned then this is going */
- /* straight into the inflight queue */
- evdns_request_insert(req, &REQ_HEAD(base, req->trans_id));
- base->global_requests_inflight++;
- evdns_request_transmit(req);
- } else {
- evdns_request_insert(req, &base->req_waiting_head);
- base->global_requests_waiting++;
- }
-}
-
-/* exported function */
-void
-evdns_cancel_request(struct evdns_base *base, struct evdns_request *handle)
-{
- struct request *req;
-
- if (!handle->current_req)
- return;
-
- if (!base) {
- /* This redundancy is silly; can we fix it? (Not for 2.0) XXXX */
- base = handle->base;
- if (!base)
- base = handle->current_req->base;
- }
-
- EVDNS_LOCK(base);
- if (handle->pending_cb) {
- EVDNS_UNLOCK(base);
- return;
- }
-
- req = handle->current_req;
- ASSERT_VALID_REQUEST(req);
-
- reply_schedule_callback(req, 0, DNS_ERR_CANCEL, NULL);
- if (req->ns) {
- /* remove from inflight queue */
- request_finished(req, &REQ_HEAD(base, req->trans_id), 1);
- } else {
- /* remove from global_waiting head */
- request_finished(req, &base->req_waiting_head, 1);
- }
- EVDNS_UNLOCK(base);
-}
-
-/* exported function */
-struct evdns_request *
-evdns_base_resolve_ipv4(struct evdns_base *base, const char *name, int flags,
- evdns_callback_type callback, void *ptr) {
- struct evdns_request *handle;
- struct request *req;
- log(EVDNS_LOG_DEBUG, "Resolve requested for %s", name);
- handle = mm_calloc(1, sizeof(*handle));
- if (handle == NULL)
- return NULL;
- EVDNS_LOCK(base);
- if (flags & DNS_QUERY_NO_SEARCH) {
- req =
- request_new(base, handle, TYPE_A, name, flags,
- callback, ptr);
- if (req)
- request_submit(req);
- } else {
- search_request_new(base, handle, TYPE_A, name, flags,
- callback, ptr);
- }
- if (handle->current_req == NULL) {
- mm_free(handle);
- handle = NULL;
- }
- EVDNS_UNLOCK(base);
- return handle;
-}
-
-int evdns_resolve_ipv4(const char *name, int flags,
- evdns_callback_type callback, void *ptr)
-{
- return evdns_base_resolve_ipv4(current_base, name, flags, callback, ptr)
- ? 0 : -1;
-}
-
-
-/* exported function */
-struct evdns_request *
-evdns_base_resolve_ipv6(struct evdns_base *base,
- const char *name, int flags,
- evdns_callback_type callback, void *ptr)
-{
- struct evdns_request *handle;
- struct request *req;
- log(EVDNS_LOG_DEBUG, "Resolve requested for %s", name);
- handle = mm_calloc(1, sizeof(*handle));
- if (handle == NULL)
- return NULL;
- EVDNS_LOCK(base);
- if (flags & DNS_QUERY_NO_SEARCH) {
- req = request_new(base, handle, TYPE_AAAA, name, flags,
- callback, ptr);
- if (req)
- request_submit(req);
- } else {
- search_request_new(base, handle, TYPE_AAAA, name, flags,
- callback, ptr);
- }
- if (handle->current_req == NULL) {
- mm_free(handle);
- handle = NULL;
- }
- EVDNS_UNLOCK(base);
- return handle;
-}
-
-int evdns_resolve_ipv6(const char *name, int flags,
- evdns_callback_type callback, void *ptr) {
- return evdns_base_resolve_ipv6(current_base, name, flags, callback, ptr)
- ? 0 : -1;
-}
-
-struct evdns_request *
-evdns_base_resolve_reverse(struct evdns_base *base, const struct in_addr *in, int flags, evdns_callback_type callback, void *ptr) {
- char buf[32];
- struct evdns_request *handle;
- struct request *req;
- u32 a;
- EVUTIL_ASSERT(in);
- a = ntohl(in->s_addr);
- evutil_snprintf(buf, sizeof(buf), "%d.%d.%d.%d.in-addr.arpa",
- (int)(u8)((a )&0xff),
- (int)(u8)((a>>8 )&0xff),
- (int)(u8)((a>>16)&0xff),
- (int)(u8)((a>>24)&0xff));
- handle = mm_calloc(1, sizeof(*handle));
- if (handle == NULL)
- return NULL;
- log(EVDNS_LOG_DEBUG, "Resolve requested for %s (reverse)", buf);
- EVDNS_LOCK(base);
- req = request_new(base, handle, TYPE_PTR, buf, flags, callback, ptr);
- if (req)
- request_submit(req);
- if (handle->current_req == NULL) {
- mm_free(handle);
- handle = NULL;
- }
- EVDNS_UNLOCK(base);
- return (handle);
-}
-
-int evdns_resolve_reverse(const struct in_addr *in, int flags, evdns_callback_type callback, void *ptr) {
- return evdns_base_resolve_reverse(current_base, in, flags, callback, ptr)
- ? 0 : -1;
-}
-
-struct evdns_request *
-evdns_base_resolve_reverse_ipv6(struct evdns_base *base, const struct in6_addr *in, int flags, evdns_callback_type callback, void *ptr) {
- /* 32 nybbles, 32 periods, "ip6.arpa", NUL. */
- char buf[73];
- char *cp;
- struct evdns_request *handle;
- struct request *req;
- int i;
- EVUTIL_ASSERT(in);
- cp = buf;
- for (i=15; i >= 0; --i) {
- u8 byte = in->s6_addr[i];
- *cp++ = "0123456789abcdef"[byte & 0x0f];
- *cp++ = '.';
- *cp++ = "0123456789abcdef"[byte >> 4];
- *cp++ = '.';
- }
- EVUTIL_ASSERT(cp + strlen("ip6.arpa") < buf+sizeof(buf));
- memcpy(cp, "ip6.arpa", strlen("ip6.arpa")+1);
- handle = mm_calloc(1, sizeof(*handle));
- if (handle == NULL)
- return NULL;
- log(EVDNS_LOG_DEBUG, "Resolve requested for %s (reverse)", buf);
- EVDNS_LOCK(base);
- req = request_new(base, handle, TYPE_PTR, buf, flags, callback, ptr);
- if (req)
- request_submit(req);
- if (handle->current_req == NULL) {
- mm_free(handle);
- handle = NULL;
- }
- EVDNS_UNLOCK(base);
- return (handle);
-}
-
-int evdns_resolve_reverse_ipv6(const struct in6_addr *in, int flags, evdns_callback_type callback, void *ptr) {
- return evdns_base_resolve_reverse_ipv6(current_base, in, flags, callback, ptr)
- ? 0 : -1;
-}
-
-/* ================================================================= */
-/* Search support */
-/* */
-/* the libc resolver has support for searching a number of domains */
-/* to find a name. If nothing else then it takes the single domain */
-/* from the gethostname() call. */
-/* */
-/* It can also be configured via the domain and search options in a */
-/* resolv.conf. */
-/* */
-/* The ndots option controls how many dots it takes for the resolver */
-/* to decide that a name is non-local and so try a raw lookup first. */
-
-struct search_domain {
- int len;
- struct search_domain *next;
- /* the text string is appended to this structure */
-};
-
-struct search_state {
- int refcount;
- int ndots;
- int num_domains;
- struct search_domain *head;
-};
-
-static void
-search_state_decref(struct search_state *const state) {
- if (!state) return;
- state->refcount--;
- if (!state->refcount) {
- struct search_domain *next, *dom;
- for (dom = state->head; dom; dom = next) {
- next = dom->next;
- mm_free(dom);
- }
- mm_free(state);
- }
-}
-
-static struct search_state *
-search_state_new(void) {
- struct search_state *state = (struct search_state *) mm_malloc(sizeof(struct search_state));
- if (!state) return NULL;
- memset(state, 0, sizeof(struct search_state));
- state->refcount = 1;
- state->ndots = 1;
-
- return state;
-}
-
-static void
-search_postfix_clear(struct evdns_base *base) {
- search_state_decref(base->global_search_state);
-
- base->global_search_state = search_state_new();
-}
-
-/* exported function */
-void
-evdns_base_search_clear(struct evdns_base *base)
-{
- EVDNS_LOCK(base);
- search_postfix_clear(base);
- EVDNS_UNLOCK(base);
-}
-
-void
-evdns_search_clear(void) {
- evdns_base_search_clear(current_base);
-}
-
-static void
-search_postfix_add(struct evdns_base *base, const char *domain) {
- size_t domain_len;
- struct search_domain *sdomain;
- while (domain[0] == '.') domain++;
- domain_len = strlen(domain);
-
- ASSERT_LOCKED(base);
- if (!base->global_search_state) base->global_search_state = search_state_new();
- if (!base->global_search_state) return;
- base->global_search_state->num_domains++;
-
- sdomain = (struct search_domain *) mm_malloc(sizeof(struct search_domain) + domain_len);
- if (!sdomain) return;
- memcpy( ((u8 *) sdomain) + sizeof(struct search_domain), domain, domain_len);
- sdomain->next = base->global_search_state->head;
- sdomain->len = (int) domain_len;
-
- base->global_search_state->head = sdomain;
-}
-
-/* reverse the order of members in the postfix list. This is needed because, */
-/* when parsing resolv.conf we push elements in the wrong order */
-static void
-search_reverse(struct evdns_base *base) {
- struct search_domain *cur, *prev = NULL, *next;
- ASSERT_LOCKED(base);
- cur = base->global_search_state->head;
- while (cur) {
- next = cur->next;
- cur->next = prev;
- prev = cur;
- cur = next;
- }
-
- base->global_search_state->head = prev;
-}
-
-/* exported function */
-void
-evdns_base_search_add(struct evdns_base *base, const char *domain) {
- EVDNS_LOCK(base);
- search_postfix_add(base, domain);
- EVDNS_UNLOCK(base);
-}
-void
-evdns_search_add(const char *domain) {
- evdns_base_search_add(current_base, domain);
-}
-
-/* exported function */
-void
-evdns_base_search_ndots_set(struct evdns_base *base, const int ndots) {
- EVDNS_LOCK(base);
- if (!base->global_search_state) base->global_search_state = search_state_new();
- if (base->global_search_state)
- base->global_search_state->ndots = ndots;
- EVDNS_UNLOCK(base);
-}
-void
-evdns_search_ndots_set(const int ndots) {
- evdns_base_search_ndots_set(current_base, ndots);
-}
-
-static void
-search_set_from_hostname(struct evdns_base *base) {
- char hostname[HOST_NAME_MAX + 1], *domainname;
-
- ASSERT_LOCKED(base);
- search_postfix_clear(base);
- if (gethostname(hostname, sizeof(hostname))) return;
- domainname = strchr(hostname, '.');
- if (!domainname) return;
- search_postfix_add(base, domainname);
-}
-
-/* warning: returns malloced string */
-static char *
-search_make_new(const struct search_state *const state, int n, const char *const base_name) {
- const size_t base_len = strlen(base_name);
- const char need_to_append_dot = base_name[base_len - 1] == '.' ? 0 : 1;
- struct search_domain *dom;
-
- for (dom = state->head; dom; dom = dom->next) {
- if (!n--) {
- /* this is the postfix we want */
- /* the actual postfix string is kept at the end of the structure */
- const u8 *const postfix = ((u8 *) dom) + sizeof(struct search_domain);
- const int postfix_len = dom->len;
- char *const newname = (char *) mm_malloc(base_len + need_to_append_dot + postfix_len + 1);
- if (!newname) return NULL;
- memcpy(newname, base_name, base_len);
- if (need_to_append_dot) newname[base_len] = '.';
- memcpy(newname + base_len + need_to_append_dot, postfix, postfix_len);
- newname[base_len + need_to_append_dot + postfix_len] = 0;
- return newname;
- }
- }
-
- /* we ran off the end of the list and still didn't find the requested string */
- EVUTIL_ASSERT(0);
- return NULL; /* unreachable; stops warnings in some compilers. */
-}
-
-static struct request *
-search_request_new(struct evdns_base *base, struct evdns_request *handle,
- int type, const char *const name, int flags,
- evdns_callback_type user_callback, void *user_arg) {
- ASSERT_LOCKED(base);
- EVUTIL_ASSERT(type == TYPE_A || type == TYPE_AAAA);
- EVUTIL_ASSERT(handle->current_req == NULL);
- if ( ((flags & DNS_QUERY_NO_SEARCH) == 0) &&
- base->global_search_state &&
- base->global_search_state->num_domains) {
- /* we have some domains to search */
- struct request *req;
- if (string_num_dots(name) >= base->global_search_state->ndots) {
- req = request_new(base, handle, type, name, flags, user_callback, user_arg);
- if (!req) return NULL;
- handle->search_index = -1;
- } else {
- char *const new_name = search_make_new(base->global_search_state, 0, name);
- if (!new_name) return NULL;
- req = request_new(base, handle, type, new_name, flags, user_callback, user_arg);
- mm_free(new_name);
- if (!req) return NULL;
- handle->search_index = 0;
- }
- EVUTIL_ASSERT(handle->search_origname == NULL);
- handle->search_origname = mm_strdup(name);
- if (handle->search_origname == NULL) {
- /* XXX Should we dealloc req? If yes, how? */
- return NULL;
- }
- handle->search_state = base->global_search_state;
- handle->search_flags = flags;
- base->global_search_state->refcount++;
- request_submit(req);
- return req;
- } else {
- struct request *const req = request_new(base, handle, type, name, flags, user_callback, user_arg);
- if (!req) return NULL;
- request_submit(req);
- return req;
- }
-}
-
-/* this is called when a request has failed to find a name. We need to check */
-/* if it is part of a search and, if so, try the next name in the list */
-/* returns: */
-/* 0 another request has been submitted */
-/* 1 no more requests needed */
-static int
-search_try_next(struct evdns_request *const handle) {
- struct request *req = handle->current_req;
- struct evdns_base *base = req->base;
- struct request *newreq;
- ASSERT_LOCKED(base);
- if (handle->search_state) {
- /* it is part of a search */
- char *new_name;
- handle->search_index++;
- if (handle->search_index >= handle->search_state->num_domains) {
- /* no more postfixes to try, however we may need to try */
- /* this name without a postfix */
- if (string_num_dots(handle->search_origname) < handle->search_state->ndots) {
- /* yep, we need to try it raw */
- newreq = request_new(base, NULL, req->request_type, handle->search_origname, handle->search_flags, req->user_callback, req->user_pointer);
- log(EVDNS_LOG_DEBUG, "Search: trying raw query %s", handle->search_origname);
- if (newreq) {
- search_request_finished(handle);
- goto submit_next;
- }
- }
- return 1;
- }
-
- new_name = search_make_new(handle->search_state, handle->search_index, handle->search_origname);
- if (!new_name) return 1;
- log(EVDNS_LOG_DEBUG, "Search: now trying %s (%d)", new_name, handle->search_index);
- newreq = request_new(base, NULL, req->request_type, new_name, handle->search_flags, req->user_callback, req->user_pointer);
- mm_free(new_name);
- if (!newreq) return 1;
- goto submit_next;
- }
- return 1;
-
-submit_next:
- request_finished(req, &REQ_HEAD(req->base, req->trans_id), 0);
- handle->current_req = newreq;
- newreq->handle = handle;
- request_submit(newreq);
- return 0;
-}
-
-static void
-search_request_finished(struct evdns_request *const handle) {
- ASSERT_LOCKED(handle->current_req->base);
- if (handle->search_state) {
- search_state_decref(handle->search_state);
- handle->search_state = NULL;
- }
- if (handle->search_origname) {
- mm_free(handle->search_origname);
- handle->search_origname = NULL;
- }
-}
-
-/* ================================================================= */
-/* Parsing resolv.conf files */
-
-static void
-evdns_resolv_set_defaults(struct evdns_base *base, int flags) {
- /* if the file isn't found then we assume a local resolver */
- ASSERT_LOCKED(base);
- if (flags & DNS_OPTION_SEARCH) search_set_from_hostname(base);
- if (flags & DNS_OPTION_NAMESERVERS) evdns_base_nameserver_ip_add(base,"127.0.0.1");
-}
-
-#ifndef _EVENT_HAVE_STRTOK_R
-static char *
-strtok_r(char *s, const char *delim, char **state) {
- char *cp, *start;
- start = cp = s ? s : *state;
- if (!cp)
- return NULL;
- while (*cp && !strchr(delim, *cp))
- ++cp;
- if (!*cp) {
- if (cp == start)
- return NULL;
- *state = NULL;
- return start;
- } else {
- *cp++ = '\0';
- *state = cp;
- return start;
- }
-}
-#endif
-
-/* helper version of atoi which returns -1 on error */
-static int
-strtoint(const char *const str)
-{
- char *endptr;
- const int r = strtol(str, &endptr, 10);
- if (*endptr) return -1;
- return r;
-}
-
-/* Parse a number of seconds into a timeval; return -1 on error. */
-static int
-strtotimeval(const char *const str, struct timeval *out)
-{
- double d;
- char *endptr;
- d = strtod(str, &endptr);
- if (*endptr) return -1;
- if (d < 0) return -1;
- out->tv_sec = (int) d;
- out->tv_usec = (int) ((d - (int) d)*1000000);
- if (out->tv_sec == 0 && out->tv_usec < 1000) /* less than 1 msec */
- return -1;
- return 0;
-}
-
-/* helper version of atoi that returns -1 on error and clips to bounds. */
-static int
-strtoint_clipped(const char *const str, int min, int max)
-{
- int r = strtoint(str);
- if (r == -1)
- return r;
- else if (r<min)
- return min;
- else if (r>max)
- return max;
- else
- return r;
-}
-
-static int
-evdns_base_set_max_requests_inflight(struct evdns_base *base, int maxinflight)
-{
- int old_n_heads = base->n_req_heads, n_heads;
- struct request **old_heads = base->req_heads, **new_heads, *req;
- int i;
-
- ASSERT_LOCKED(base);
- if (maxinflight < 1)
- maxinflight = 1;
- n_heads = (maxinflight+4) / 5;
- EVUTIL_ASSERT(n_heads > 0);
- new_heads = mm_calloc(n_heads, sizeof(struct request*));
- if (!new_heads)
- return (-1);
- if (old_heads) {
- for (i = 0; i < old_n_heads; ++i) {
- while (old_heads[i]) {
- req = old_heads[i];
- evdns_request_remove(req, &old_heads[i]);
- evdns_request_insert(req, &new_heads[req->trans_id % n_heads]);
- }
- }
- mm_free(old_heads);
- }
- base->req_heads = new_heads;
- base->n_req_heads = n_heads;
- base->global_max_requests_inflight = maxinflight;
- return (0);
-}
-
-/* exported function */
-int
-evdns_base_set_option(struct evdns_base *base,
- const char *option, const char *val)
-{
- int res;
- EVDNS_LOCK(base);
- res = evdns_base_set_option_impl(base, option, val, DNS_OPTIONS_ALL);
- EVDNS_UNLOCK(base);
- return res;
-}
-
-static inline int
-str_matches_option(const char *s1, const char *optionname)
-{
- /* Option names are given as "option:" We accept either 'option' in
- * s1, or 'option:randomjunk'. The latter form is to implement the
- * resolv.conf parser. */
- size_t optlen = strlen(optionname);
- size_t slen = strlen(s1);
- if (slen == optlen || slen == optlen - 1)
- return !strncmp(s1, optionname, slen);
- else if (slen > optlen)
- return !strncmp(s1, optionname, optlen);
- else
- return 0;
-}
-
-static int
-evdns_base_set_option_impl(struct evdns_base *base,
- const char *option, const char *val, int flags)
-{
- ASSERT_LOCKED(base);
- if (str_matches_option(option, "ndots:")) {
- const int ndots = strtoint(val);
- if (ndots == -1) return -1;
- if (!(flags & DNS_OPTION_SEARCH)) return 0;
- log(EVDNS_LOG_DEBUG, "Setting ndots to %d", ndots);
- if (!base->global_search_state) base->global_search_state = search_state_new();
- if (!base->global_search_state) return -1;
- base->global_search_state->ndots = ndots;
- } else if (str_matches_option(option, "timeout:")) {
- struct timeval tv;
- if (strtotimeval(val, &tv) == -1) return -1;
- if (!(flags & DNS_OPTION_MISC)) return 0;
- log(EVDNS_LOG_DEBUG, "Setting timeout to %s", val);
- memcpy(&base->global_timeout, &tv, sizeof(struct timeval));
- } else if (str_matches_option(option, "getaddrinfo-allow-skew:")) {
- struct timeval tv;
- if (strtotimeval(val, &tv) == -1) return -1;
- if (!(flags & DNS_OPTION_MISC)) return 0;
- log(EVDNS_LOG_DEBUG, "Setting getaddrinfo-allow-skew to %s",
- val);
- memcpy(&base->global_getaddrinfo_allow_skew, &tv,
- sizeof(struct timeval));
- } else if (str_matches_option(option, "max-timeouts:")) {
- const int maxtimeout = strtoint_clipped(val, 1, 255);
- if (maxtimeout == -1) return -1;
- if (!(flags & DNS_OPTION_MISC)) return 0;
- log(EVDNS_LOG_DEBUG, "Setting maximum allowed timeouts to %d",
- maxtimeout);
- base->global_max_nameserver_timeout = maxtimeout;
- } else if (str_matches_option(option, "max-inflight:")) {
- const int maxinflight = strtoint_clipped(val, 1, 65000);
- if (maxinflight == -1) return -1;
- if (!(flags & DNS_OPTION_MISC)) return 0;
- log(EVDNS_LOG_DEBUG, "Setting maximum inflight requests to %d",
- maxinflight);
- evdns_base_set_max_requests_inflight(base, maxinflight);
- } else if (str_matches_option(option, "attempts:")) {
- int retries = strtoint(val);
- if (retries == -1) return -1;
- if (retries > 255) retries = 255;
- if (!(flags & DNS_OPTION_MISC)) return 0;
- log(EVDNS_LOG_DEBUG, "Setting retries to %d", retries);
- base->global_max_retransmits = retries;
- } else if (str_matches_option(option, "randomize-case:")) {
- int randcase = strtoint(val);
- if (!(flags & DNS_OPTION_MISC)) return 0;
- base->global_randomize_case = randcase;
- } else if (str_matches_option(option, "bind-to:")) {
- /* XXX This only applies to successive nameservers, not
- * to already-configured ones. We might want to fix that. */
- int len = sizeof(base->global_outgoing_address);
- if (!(flags & DNS_OPTION_NAMESERVERS)) return 0;
- if (evutil_parse_sockaddr_port(val,
- (struct sockaddr*)&base->global_outgoing_address, &len))
- return -1;
- base->global_outgoing_addrlen = len;
- } else if (str_matches_option(option, "initial-probe-timeout:")) {
- struct timeval tv;
- if (strtotimeval(val, &tv) == -1) return -1;
- if (tv.tv_sec > 3600)
- tv.tv_sec = 3600;
- if (!(flags & DNS_OPTION_MISC)) return 0;
- log(EVDNS_LOG_DEBUG, "Setting initial probe timeout to %s",
- val);
- memcpy(&base->global_nameserver_probe_initial_timeout, &tv,
- sizeof(tv));
- }
- return 0;
-}
-
-int
-evdns_set_option(const char *option, const char *val, int flags)
-{
- if (!current_base)
- current_base = evdns_base_new(NULL, 0);
- return evdns_base_set_option(current_base, option, val);
-}
-
-static void
-resolv_conf_parse_line(struct evdns_base *base, char *const start, int flags) {
- char *strtok_state;
- static const char *const delims = " \t";
-#define NEXT_TOKEN strtok_r(NULL, delims, &strtok_state)
-
-
- char *const first_token = strtok_r(start, delims, &strtok_state);
- ASSERT_LOCKED(base);
- if (!first_token) return;
-
- if (!strcmp(first_token, "nameserver") && (flags & DNS_OPTION_NAMESERVERS)) {
- const char *const nameserver = NEXT_TOKEN;
-
- if (nameserver)
- evdns_base_nameserver_ip_add(base, nameserver);
- } else if (!strcmp(first_token, "domain") && (flags & DNS_OPTION_SEARCH)) {
- const char *const domain = NEXT_TOKEN;
- if (domain) {
- search_postfix_clear(base);
- search_postfix_add(base, domain);
- }
- } else if (!strcmp(first_token, "search") && (flags & DNS_OPTION_SEARCH)) {
- const char *domain;
- search_postfix_clear(base);
-
- while ((domain = NEXT_TOKEN)) {
- search_postfix_add(base, domain);
- }
- search_reverse(base);
- } else if (!strcmp(first_token, "options")) {
- const char *option;
- while ((option = NEXT_TOKEN)) {
- const char *val = strchr(option, ':');
- evdns_base_set_option_impl(base, option, val ? val+1 : "", flags);
- }
- }
-#undef NEXT_TOKEN
-}
-
-/* exported function */
-/* returns: */
-/* 0 no errors */
-/* 1 failed to open file */
-/* 2 failed to stat file */
-/* 3 file too large */
-/* 4 out of memory */
-/* 5 short read from file */
-int
-evdns_base_resolv_conf_parse(struct evdns_base *base, int flags, const char *const filename) {
- int res;
- EVDNS_LOCK(base);
- res = evdns_base_resolv_conf_parse_impl(base, flags, filename);
- EVDNS_UNLOCK(base);
- return res;
-}
-
-static char *
-evdns_get_default_hosts_filename(void)
-{
-#ifdef WIN32
- /* Windows is a little coy about where it puts its configuration
- * files. Sure, they're _usually_ in C:\windows\system32, but
- * there's no reason in principle they couldn't be in
- * W:\hoboken chicken emergency\
- */
- char path[MAX_PATH+1];
- static const char hostfile[] = "\\drivers\\etc\\hosts";
- char *path_out;
- size_t len_out;
-
- if (! SHGetSpecialFolderPathA(NULL, path, CSIDL_SYSTEM, 0))
- return NULL;
- len_out = strlen(path)+strlen(hostfile);
- path_out = mm_malloc(len_out+1);
- evutil_snprintf(path_out, len_out, "%s%s", path, hostfile);
- return path_out;
-#else
- return mm_strdup("/etc/hosts");
-#endif
-}
-
-static int
-evdns_base_resolv_conf_parse_impl(struct evdns_base *base, int flags, const char *const filename) {
- size_t n;
- char *resolv;
- char *start;
- int err = 0;
-
- log(EVDNS_LOG_DEBUG, "Parsing resolv.conf file %s", filename);
-
- if (flags & DNS_OPTION_HOSTSFILE) {
- char *fname = evdns_get_default_hosts_filename();
- evdns_base_load_hosts(base, fname);
- if (fname)
- mm_free(fname);
- }
-
- if ((err = evutil_read_file(filename, &resolv, &n, 0)) < 0) {
- if (err == -1) {
- /* No file. */
- evdns_resolv_set_defaults(base, flags);
- return 1;
- } else {
- return 2;
- }
- }
-
- start = resolv;
- for (;;) {
- char *const newline = strchr(start, '\n');
- if (!newline) {
- resolv_conf_parse_line(base, start, flags);
- break;
- } else {
- *newline = 0;
- resolv_conf_parse_line(base, start, flags);
- start = newline + 1;
- }
- }
-
- if (!base->server_head && (flags & DNS_OPTION_NAMESERVERS)) {
- /* no nameservers were configured. */
- evdns_base_nameserver_ip_add(base, "127.0.0.1");
- err = 6;
- }
- if (flags & DNS_OPTION_SEARCH && (!base->global_search_state || base->global_search_state->num_domains == 0)) {
- search_set_from_hostname(base);
- }
-
- mm_free(resolv);
- return err;
-}
-
-int
-evdns_resolv_conf_parse(int flags, const char *const filename) {
- if (!current_base)
- current_base = evdns_base_new(NULL, 0);
- return evdns_base_resolv_conf_parse(current_base, flags, filename);
-}
-
-
-#ifdef WIN32
-/* Add multiple nameservers from a space-or-comma-separated list. */
-static int
-evdns_nameserver_ip_add_line(struct evdns_base *base, const char *ips) {
- const char *addr;
- char *buf;
- int r;
- ASSERT_LOCKED(base);
- while (*ips) {
- while (isspace(*ips) || *ips == ',' || *ips == '\t')
- ++ips;
- addr = ips;
- while (isdigit(*ips) || *ips == '.' || *ips == ':' ||
- *ips=='[' || *ips==']')
- ++ips;
- buf = mm_malloc(ips-addr+1);
- if (!buf) return 4;
- memcpy(buf, addr, ips-addr);
- buf[ips-addr] = '\0';
- r = evdns_base_nameserver_ip_add(base, buf);
- mm_free(buf);
- if (r) return r;
- }
- return 0;
-}
-
-typedef DWORD(WINAPI *GetNetworkParams_fn_t)(FIXED_INFO *, DWORD*);
-
-/* Use the windows GetNetworkParams interface in iphlpapi.dll to */
-/* figure out what our nameservers are. */
-static int
-load_nameservers_with_getnetworkparams(struct evdns_base *base)
-{
- /* Based on MSDN examples and inspection of c-ares code. */
- FIXED_INFO *fixed;
- HMODULE handle = 0;
- ULONG size = sizeof(FIXED_INFO);
- void *buf = NULL;
- int status = 0, r, added_any;
- IP_ADDR_STRING *ns;
- GetNetworkParams_fn_t fn;
-
- ASSERT_LOCKED(base);
- if (!(handle = evutil_load_windows_system_library(
- TEXT("iphlpapi.dll")))) {
- log(EVDNS_LOG_WARN, "Could not open iphlpapi.dll");
- status = -1;
- goto done;
- }
- if (!(fn = (GetNetworkParams_fn_t) GetProcAddress(handle, "GetNetworkParams"))) {
- log(EVDNS_LOG_WARN, "Could not get address of function.");
- status = -1;
- goto done;
- }
-
- buf = mm_malloc(size);
- if (!buf) { status = 4; goto done; }
- fixed = buf;
- r = fn(fixed, &size);
- if (r != ERROR_SUCCESS && r != ERROR_BUFFER_OVERFLOW) {
- status = -1;
- goto done;
- }
- if (r != ERROR_SUCCESS) {
- mm_free(buf);
- buf = mm_malloc(size);
- if (!buf) { status = 4; goto done; }
- fixed = buf;
- r = fn(fixed, &size);
- if (r != ERROR_SUCCESS) {
- log(EVDNS_LOG_DEBUG, "fn() failed.");
- status = -1;
- goto done;
- }
- }
-
- EVUTIL_ASSERT(fixed);
- added_any = 0;
- ns = &(fixed->DnsServerList);
- while (ns) {
- r = evdns_nameserver_ip_add_line(base, ns->IpAddress.String);
- if (r) {
- log(EVDNS_LOG_DEBUG,"Could not add nameserver %s to list,error: %d",
- (ns->IpAddress.String),(int)GetLastError());
- status = r;
- } else {
- ++added_any;
- log(EVDNS_LOG_DEBUG,"Successfully added %s as nameserver",ns->IpAddress.String);
- }
-
- ns = ns->Next;
- }
-
- if (!added_any) {
- log(EVDNS_LOG_DEBUG, "No nameservers added.");
- if (status == 0)
- status = -1;
- } else {
- status = 0;
- }
-
- done:
- if (buf)
- mm_free(buf);
- if (handle)
- FreeLibrary(handle);
- return status;
-}
-
-static int
-config_nameserver_from_reg_key(struct evdns_base *base, HKEY key, const TCHAR *subkey)
-{
- char *buf;
- DWORD bufsz = 0, type = 0;
- int status = 0;
-
- ASSERT_LOCKED(base);
- if (RegQueryValueEx(key, subkey, 0, &type, NULL, &bufsz)
- != ERROR_MORE_DATA)
- return -1;
- if (!(buf = mm_malloc(bufsz)))
- return -1;
-
- if (RegQueryValueEx(key, subkey, 0, &type, (LPBYTE)buf, &bufsz)
- == ERROR_SUCCESS && bufsz > 1) {
- status = evdns_nameserver_ip_add_line(base,buf);
- }
-
- mm_free(buf);
- return status;
-}
-
-#define SERVICES_KEY TEXT("System\\CurrentControlSet\\Services\\")
-#define WIN_NS_9X_KEY SERVICES_KEY TEXT("VxD\\MSTCP")
-#define WIN_NS_NT_KEY SERVICES_KEY TEXT("Tcpip\\Parameters")
-
-static int
-load_nameservers_from_registry(struct evdns_base *base)
-{
- int found = 0;
- int r;
-#define TRY(k, name) \
- if (!found && config_nameserver_from_reg_key(base,k,TEXT(name)) == 0) { \
- log(EVDNS_LOG_DEBUG,"Found nameservers in %s/%s",#k,name); \
- found = 1; \
- } else if (!found) { \
- log(EVDNS_LOG_DEBUG,"Didn't find nameservers in %s/%s", \
- #k,#name); \
- }
-
- ASSERT_LOCKED(base);
-
- if (((int)GetVersion()) > 0) { /* NT */
- HKEY nt_key = 0, interfaces_key = 0;
-
- if (RegOpenKeyEx(HKEY_LOCAL_MACHINE, WIN_NS_NT_KEY, 0,
- KEY_READ, &nt_key) != ERROR_SUCCESS) {
- log(EVDNS_LOG_DEBUG,"Couldn't open nt key, %d",(int)GetLastError());
- return -1;
- }
- r = RegOpenKeyEx(nt_key, TEXT("Interfaces"), 0,
- KEY_QUERY_VALUE|KEY_ENUMERATE_SUB_KEYS,
- &interfaces_key);
- if (r != ERROR_SUCCESS) {
- log(EVDNS_LOG_DEBUG,"Couldn't open interfaces key, %d",(int)GetLastError());
- return -1;
- }
- TRY(nt_key, "NameServer");
- TRY(nt_key, "DhcpNameServer");
- TRY(interfaces_key, "NameServer");
- TRY(interfaces_key, "DhcpNameServer");
- RegCloseKey(interfaces_key);
- RegCloseKey(nt_key);
- } else {
- HKEY win_key = 0;
- if (RegOpenKeyEx(HKEY_LOCAL_MACHINE, WIN_NS_9X_KEY, 0,
- KEY_READ, &win_key) != ERROR_SUCCESS) {
- log(EVDNS_LOG_DEBUG, "Couldn't open registry key, %d", (int)GetLastError());
- return -1;
- }
- TRY(win_key, "NameServer");
- RegCloseKey(win_key);
- }
-
- if (found == 0) {
- log(EVDNS_LOG_WARN,"Didn't find any nameservers.");
- }
-
- return found ? 0 : -1;
-#undef TRY
-}
-
-int
-evdns_base_config_windows_nameservers(struct evdns_base *base)
-{
- int r;
- char *fname;
- if (base == NULL)
- base = current_base;
- if (base == NULL)
- return -1;
- EVDNS_LOCK(base);
- if (load_nameservers_with_getnetworkparams(base) == 0) {
- EVDNS_UNLOCK(base);
- return 0;
- }
- r = load_nameservers_from_registry(base);
-
- fname = evdns_get_default_hosts_filename();
- evdns_base_load_hosts(base, fname);
- if (fname)
- mm_free(fname);
-
- EVDNS_UNLOCK(base);
- return r;
-}
-
-int
-evdns_config_windows_nameservers(void)
-{
- if (!current_base) {
- current_base = evdns_base_new(NULL, 1);
- return current_base == NULL ? -1 : 0;
- } else {
- return evdns_base_config_windows_nameservers(current_base);
- }
-}
-#endif
-
-struct evdns_base *
-evdns_base_new(struct event_base *event_base, int initialize_nameservers)
-{
- struct evdns_base *base;
-
- if (evutil_secure_rng_init() < 0) {
- log(EVDNS_LOG_WARN, "Unable to seed random number generator; "
- "DNS can't run.");
- return NULL;
- }
-
- /* Give the evutil library a hook into its evdns-enabled
- * functionality. We can't just call evdns_getaddrinfo directly or
- * else libevent-core will depend on libevent-extras. */
- evutil_set_evdns_getaddrinfo_fn(evdns_getaddrinfo);
-
- base = mm_malloc(sizeof(struct evdns_base));
- if (base == NULL)
- return (NULL);
- memset(base, 0, sizeof(struct evdns_base));
- base->req_waiting_head = NULL;
-
- EVTHREAD_ALLOC_LOCK(base->lock, EVTHREAD_LOCKTYPE_RECURSIVE);
- EVDNS_LOCK(base);
-
- /* Set max requests inflight and allocate req_heads. */
- base->req_heads = NULL;
-
- evdns_base_set_max_requests_inflight(base, 64);
-
- base->server_head = NULL;
- base->event_base = event_base;
- base->global_good_nameservers = base->global_requests_inflight =
- base->global_requests_waiting = 0;
-
- base->global_timeout.tv_sec = 5;
- base->global_timeout.tv_usec = 0;
- base->global_max_reissues = 1;
- base->global_max_retransmits = 3;
- base->global_max_nameserver_timeout = 3;
- base->global_search_state = NULL;
- base->global_randomize_case = 1;
- base->global_getaddrinfo_allow_skew.tv_sec = 3;
- base->global_getaddrinfo_allow_skew.tv_usec = 0;
- base->global_nameserver_probe_initial_timeout.tv_sec = 10;
- base->global_nameserver_probe_initial_timeout.tv_usec = 0;
-
- TAILQ_INIT(&base->hostsdb);
-
- if (initialize_nameservers) {
- int r;
-#ifdef WIN32
- r = evdns_base_config_windows_nameservers(base);
-#else
- r = evdns_base_resolv_conf_parse(base, DNS_OPTIONS_ALL, "/etc/resolv.conf");
-#endif
- if (r == -1) {
- evdns_base_free_and_unlock(base, 0);
- return NULL;
- }
- }
- EVDNS_UNLOCK(base);
- return base;
-}
-
-int
-evdns_init(void)
-{
- struct evdns_base *base = evdns_base_new(NULL, 1);
- if (base) {
- current_base = base;
- return 0;
- } else {
- return -1;
- }
-}
-
-const char *
-evdns_err_to_string(int err)
-{
- switch (err) {
- case DNS_ERR_NONE: return "no error";
- case DNS_ERR_FORMAT: return "misformatted query";
- case DNS_ERR_SERVERFAILED: return "server failed";
- case DNS_ERR_NOTEXIST: return "name does not exist";
- case DNS_ERR_NOTIMPL: return "query not implemented";
- case DNS_ERR_REFUSED: return "refused";
-
- case DNS_ERR_TRUNCATED: return "reply truncated or ill-formed";
- case DNS_ERR_UNKNOWN: return "unknown";
- case DNS_ERR_TIMEOUT: return "request timed out";
- case DNS_ERR_SHUTDOWN: return "dns subsystem shut down";
- case DNS_ERR_CANCEL: return "dns request canceled";
- default: return "[Unknown error code]";
- }
-}
-
-static void
-evdns_nameserver_free(struct nameserver *server)
-{
- if (server->socket >= 0)
- evutil_closesocket(server->socket);
- (void) event_del(&server->event);
- event_debug_unassign(&server->event);
- if (server->state == 0)
- (void) event_del(&server->timeout_event);
- event_debug_unassign(&server->timeout_event);
- mm_free(server);
-}
-
-static void
-evdns_base_free_and_unlock(struct evdns_base *base, int fail_requests)
-{
- struct nameserver *server, *server_next;
- struct search_domain *dom, *dom_next;
- int i;
-
- /* Requires that we hold the lock. */
-
- /* TODO(nickm) we might need to refcount here. */
-
- for (i = 0; i < base->n_req_heads; ++i) {
- while (base->req_heads[i]) {
- if (fail_requests)
- reply_schedule_callback(base->req_heads[i], 0, DNS_ERR_SHUTDOWN, NULL);
- request_finished(base->req_heads[i], &REQ_HEAD(base, base->req_heads[i]->trans_id), 1);
- }
- }
- while (base->req_waiting_head) {
- if (fail_requests)
- reply_schedule_callback(base->req_waiting_head, 0, DNS_ERR_SHUTDOWN, NULL);
- request_finished(base->req_waiting_head, &base->req_waiting_head, 1);
- }
- base->global_requests_inflight = base->global_requests_waiting = 0;
-
- for (server = base->server_head; server; server = server_next) {
- server_next = server->next;
- evdns_nameserver_free(server);
- if (server_next == base->server_head)
- break;
- }
- base->server_head = NULL;
- base->global_good_nameservers = 0;
-
- if (base->global_search_state) {
- for (dom = base->global_search_state->head; dom; dom = dom_next) {
- dom_next = dom->next;
- mm_free(dom);
- }
- mm_free(base->global_search_state);
- base->global_search_state = NULL;
- }
-
- {
- struct hosts_entry *victim;
- while ((victim = TAILQ_FIRST(&base->hostsdb))) {
- TAILQ_REMOVE(&base->hostsdb, victim, next);
- mm_free(victim);
- }
- }
-
- mm_free(base->req_heads);
-
- EVDNS_UNLOCK(base);
- EVTHREAD_FREE_LOCK(base->lock, EVTHREAD_LOCKTYPE_RECURSIVE);
-
- mm_free(base);
-}
-
-void
-evdns_base_free(struct evdns_base *base, int fail_requests)
-{
- EVDNS_LOCK(base);
- evdns_base_free_and_unlock(base, fail_requests);
-}
-
-void
-evdns_shutdown(int fail_requests)
-{
- if (current_base) {
- struct evdns_base *b = current_base;
- current_base = NULL;
- evdns_base_free(b, fail_requests);
- }
- evdns_log_fn = NULL;
-}
-
-static int
-evdns_base_parse_hosts_line(struct evdns_base *base, char *line)
-{
- char *strtok_state;
- static const char *const delims = " \t";
- char *const addr = strtok_r(line, delims, &strtok_state);
- char *hostname, *hash;
- struct sockaddr_storage ss;
- int socklen = sizeof(ss);
- ASSERT_LOCKED(base);
-
-#define NEXT_TOKEN strtok_r(NULL, delims, &strtok_state)
-
- if (!addr || *addr == '#')
- return 0;
-
- memset(&ss, 0, sizeof(ss));
- if (evutil_parse_sockaddr_port(addr, (struct sockaddr*)&ss, &socklen)<0)
- return -1;
- if (socklen > (int)sizeof(struct sockaddr_in6))
- return -1;
-
- if (sockaddr_getport((struct sockaddr*)&ss))
- return -1;
-
- while ((hostname = NEXT_TOKEN)) {
- struct hosts_entry *he;
- size_t namelen;
- if ((hash = strchr(hostname, '#'))) {
- if (hash == hostname)
- return 0;
- *hash = '\0';
- }
-
- namelen = strlen(hostname);
-
- he = mm_calloc(1, sizeof(struct hosts_entry)+namelen);
- if (!he)
- return -1;
- EVUTIL_ASSERT(socklen <= (int)sizeof(he->addr));
- memcpy(&he->addr, &ss, socklen);
- memcpy(he->hostname, hostname, namelen+1);
- he->addrlen = socklen;
-
- TAILQ_INSERT_TAIL(&base->hostsdb, he, next);
-
- if (hash)
- return 0;
- }
-
- return 0;
-#undef NEXT_TOKEN
-}
-
-static int
-evdns_base_load_hosts_impl(struct evdns_base *base, const char *hosts_fname)
-{
- char *str=NULL, *cp, *eol;
- size_t len;
- int err=0;
-
- ASSERT_LOCKED(base);
-
- if (hosts_fname == NULL ||
- (err = evutil_read_file(hosts_fname, &str, &len, 0)) < 0) {
- char tmp[64];
- strlcpy(tmp, "127.0.0.1 localhost", sizeof(tmp));
- evdns_base_parse_hosts_line(base, tmp);
- strlcpy(tmp, "::1 localhost", sizeof(tmp));
- evdns_base_parse_hosts_line(base, tmp);
- return err ? -1 : 0;
- }
-
- /* This will break early if there is a NUL in the hosts file.
- * Probably not a problem.*/
- cp = str;
- for (;;) {
- eol = strchr(cp, '\n');
-
- if (eol) {
- *eol = '\0';
- evdns_base_parse_hosts_line(base, cp);
- cp = eol+1;
- } else {
- evdns_base_parse_hosts_line(base, cp);
- break;
- }
- }
-
- mm_free(str);
- return 0;
-}
-
-int
-evdns_base_load_hosts(struct evdns_base *base, const char *hosts_fname)
-{
- int res;
- if (!base)
- base = current_base;
- EVDNS_LOCK(base);
- res = evdns_base_load_hosts_impl(base, hosts_fname);
- EVDNS_UNLOCK(base);
- return res;
-}
-
-/* A single request for a getaddrinfo, either v4 or v6. */
-struct getaddrinfo_subrequest {
- struct evdns_request *r;
- ev_uint32_t type;
-};
-
-/* State data used to implement an in-progress getaddrinfo. */
-struct evdns_getaddrinfo_request {
- struct evdns_base *evdns_base;
- /* Copy of the modified 'hints' data that we'll use to build
- * answers. */
- struct evutil_addrinfo hints;
- /* The callback to invoke when we're done */
- evdns_getaddrinfo_cb user_cb;
- /* User-supplied data to give to the callback. */
- void *user_data;
- /* The port to use when building sockaddrs. */
- ev_uint16_t port;
- /* The sub_request for an A record (if any) */
- struct getaddrinfo_subrequest ipv4_request;
- /* The sub_request for an AAAA record (if any) */
- struct getaddrinfo_subrequest ipv6_request;
-
- /* The cname result that we were told (if any) */
- char *cname_result;
-
- /* If we have one request answered and one request still inflight,
- * then this field holds the answer from the first request... */
- struct evutil_addrinfo *pending_result;
- /* And this event is a timeout that will tell us to cancel the second
- * request if it's taking a long time. */
- struct event timeout;
-
- /* And this field holds the error code from the first request... */
- int pending_error;
- /* If this is set, the user canceled this request. */
- unsigned user_canceled : 1;
- /* If this is set, the user can no longer cancel this request; we're
- * just waiting for the free. */
- unsigned request_done : 1;
-};
-
-/* Convert an evdns errors to the equivalent getaddrinfo error. */
-static int
-evdns_err_to_getaddrinfo_err(int e1)
-{
- /* XXX Do this better! */
- if (e1 == DNS_ERR_NONE)
- return 0;
- else if (e1 == DNS_ERR_NOTEXIST)
- return EVUTIL_EAI_NONAME;
- else
- return EVUTIL_EAI_FAIL;
-}
-
-/* Return the more informative of two getaddrinfo errors. */
-static int
-getaddrinfo_merge_err(int e1, int e2)
-{
- /* XXXX be cleverer here. */
- if (e1 == 0)
- return e2;
- else
- return e1;
-}
-
-static void
-free_getaddrinfo_request(struct evdns_getaddrinfo_request *data)
-{
- /* DO NOT CALL this if either of the requests is pending. Only once
- * both callbacks have been invoked is it safe to free the request */
- if (data->pending_result)
- evutil_freeaddrinfo(data->pending_result);
- if (data->cname_result)
- mm_free(data->cname_result);
- event_del(&data->timeout);
- mm_free(data);
- return;
-}
-
-static void
-add_cname_to_reply(struct evdns_getaddrinfo_request *data,
- struct evutil_addrinfo *ai)
-{
- if (data->cname_result && ai) {
- ai->ai_canonname = data->cname_result;
- data->cname_result = NULL;
- }
-}
-
-/* Callback: invoked when one request in a mixed-format A/AAAA getaddrinfo
- * request has finished, but the other one took too long to answer. Pass
- * along the answer we got, and cancel the other request.
- */
-static void
-evdns_getaddrinfo_timeout_cb(evutil_socket_t fd, short what, void *ptr)
-{
- int v4_timedout = 0, v6_timedout = 0;
- struct evdns_getaddrinfo_request *data = ptr;
-
- /* Cancel any pending requests, and note which one */
- if (data->ipv4_request.r) {
- evdns_cancel_request(NULL, data->ipv4_request.r);
- v4_timedout = 1;
- EVDNS_LOCK(data->evdns_base);
- ++data->evdns_base->getaddrinfo_ipv4_timeouts;
- EVDNS_UNLOCK(data->evdns_base);
- }
- if (data->ipv6_request.r) {
- evdns_cancel_request(NULL, data->ipv6_request.r);
- v6_timedout = 1;
- EVDNS_LOCK(data->evdns_base);
- ++data->evdns_base->getaddrinfo_ipv6_timeouts;
- EVDNS_UNLOCK(data->evdns_base);
- }
-
- /* We only use this timeout callback when we have an answer for
- * one address. */
- EVUTIL_ASSERT(!v4_timedout || !v6_timedout);
-
- /* Report the outcome of the other request that didn't time out. */
- if (data->pending_result) {
- add_cname_to_reply(data, data->pending_result);
- data->user_cb(0, data->pending_result, data->user_data);
- data->pending_result = NULL;
- } else {
- int e = data->pending_error;
- if (!e)
- e = EVUTIL_EAI_AGAIN;
- data->user_cb(e, NULL, data->user_data);
- }
-
- if (!v4_timedout && !v6_timedout) {
- /* should be impossible? XXXX */
- free_getaddrinfo_request(data);
- }
-}
-
-static int
-evdns_getaddrinfo_set_timeout(struct evdns_base *evdns_base,
- struct evdns_getaddrinfo_request *data)
-{
- return event_add(&data->timeout, &evdns_base->global_getaddrinfo_allow_skew);
-}
-
-static inline int
-evdns_result_is_answer(int result)
-{
- return (result != DNS_ERR_NOTIMPL && result != DNS_ERR_REFUSED &&
- result != DNS_ERR_SERVERFAILED && result != DNS_ERR_CANCEL);
-}
-
-static void
-evdns_getaddrinfo_gotresolve(int result, char type, int count,
- int ttl, void *addresses, void *arg)
-{
- int i;
- struct getaddrinfo_subrequest *req = arg;
- struct getaddrinfo_subrequest *other_req;
- struct evdns_getaddrinfo_request *data;
-
- struct evutil_addrinfo *res;
-
- struct sockaddr_in sin;
- struct sockaddr_in6 sin6;
- struct sockaddr *sa;
- int socklen, addrlen;
- void *addrp;
- int err;
- int user_canceled;
-
- EVUTIL_ASSERT(req->type == DNS_IPv4_A || req->type == DNS_IPv6_AAAA);
- if (req->type == DNS_IPv4_A) {
- data = EVUTIL_UPCAST(req, struct evdns_getaddrinfo_request, ipv4_request);
- other_req = &data->ipv6_request;
- } else {
- data = EVUTIL_UPCAST(req, struct evdns_getaddrinfo_request, ipv6_request);
- other_req = &data->ipv4_request;
- }
-
- EVDNS_LOCK(data->evdns_base);
- if (evdns_result_is_answer(result)) {
- if (req->type == DNS_IPv4_A)
- ++data->evdns_base->getaddrinfo_ipv4_answered;
- else
- ++data->evdns_base->getaddrinfo_ipv6_answered;
- }
- user_canceled = data->user_canceled;
- if (other_req->r == NULL)
- data->request_done = 1;
- EVDNS_UNLOCK(data->evdns_base);
-
- req->r = NULL;
-
- if (result == DNS_ERR_CANCEL && ! user_canceled) {
- /* Internal cancel request from timeout or internal error.
- * we already answered the user. */
- if (other_req->r == NULL)
- free_getaddrinfo_request(data);
- return;
- }
-
- if (result == DNS_ERR_NONE) {
- if (count == 0)
- err = EVUTIL_EAI_NODATA;
- else
- err = 0;
- } else {
- err = evdns_err_to_getaddrinfo_err(result);
- }
-
- if (err) {
- /* Looks like we got an error. */
- if (other_req->r) {
- /* The other request is still working; maybe it will
- * succeed. */
- /* XXXX handle failure from set_timeout */
- evdns_getaddrinfo_set_timeout(data->evdns_base, data);
- data->pending_error = err;
- return;
- }
-
- if (user_canceled) {
- data->user_cb(EVUTIL_EAI_CANCEL, NULL, data->user_data);
- } else if (data->pending_result) {
- /* If we have an answer waiting, and we weren't
- * canceled, ignore this error. */
- add_cname_to_reply(data, data->pending_result);
- data->user_cb(0, data->pending_result, data->user_data);
- data->pending_result = NULL;
- } else {
- if (data->pending_error)
- err = getaddrinfo_merge_err(err,
- data->pending_error);
- data->user_cb(err, NULL, data->user_data);
- }
- free_getaddrinfo_request(data);
- return;
- } else if (user_canceled) {
- if (other_req->r) {
- /* The other request is still working; let it hit this
- * callback with EVUTIL_EAI_CANCEL callback and report
- * the failure. */
- return;
- }
- data->user_cb(EVUTIL_EAI_CANCEL, NULL, data->user_data);
- free_getaddrinfo_request(data);
- return;
- }
-
- /* Looks like we got some answers. We should turn them into addrinfos
- * and then either queue those or return them all. */
- EVUTIL_ASSERT(type == DNS_IPv4_A || type == DNS_IPv6_AAAA);
-
- if (type == DNS_IPv4_A) {
- memset(&sin, 0, sizeof(sin));
- sin.sin_family = AF_INET;
- sin.sin_port = htons(data->port);
-
- sa = (struct sockaddr *)&sin;
- socklen = sizeof(sin);
- addrlen = 4;
- addrp = &sin.sin_addr.s_addr;
- } else {
- memset(&sin6, 0, sizeof(sin6));
- sin6.sin6_family = AF_INET6;
- sin6.sin6_port = htons(data->port);
-
- sa = (struct sockaddr *)&sin6;
- socklen = sizeof(sin6);
- addrlen = 16;
- addrp = &sin6.sin6_addr.s6_addr;
- }
-
- res = NULL;
- for (i=0; i < count; ++i) {
- struct evutil_addrinfo *ai;
- memcpy(addrp, ((char*)addresses)+i*addrlen, addrlen);
- ai = evutil_new_addrinfo(sa, socklen, &data->hints);
- if (!ai) {
- if (other_req->r) {
- evdns_cancel_request(NULL, other_req->r);
- }
- data->user_cb(EVUTIL_EAI_MEMORY, NULL, data->user_data);
- if (res)
- evutil_freeaddrinfo(res);
-
- if (other_req->r == NULL)
- free_getaddrinfo_request(data);
- return;
- }
- res = evutil_addrinfo_append(res, ai);
- }
-
- if (other_req->r) {
- /* The other request is still in progress; wait for it */
- /* XXXX handle failure from set_timeout */
- evdns_getaddrinfo_set_timeout(data->evdns_base, data);
- data->pending_result = res;
- return;
- } else {
- /* The other request is done or never started; append its
- * results (if any) and return them. */
- if (data->pending_result) {
- if (req->type == DNS_IPv4_A)
- res = evutil_addrinfo_append(res,
- data->pending_result);
- else
- res = evutil_addrinfo_append(
- data->pending_result, res);
- data->pending_result = NULL;
- }
-
- /* Call the user callback. */
- add_cname_to_reply(data, res);
- data->user_cb(0, res, data->user_data);
-
- /* Free data. */
- free_getaddrinfo_request(data);
- }
-}
-
-static struct hosts_entry *
-find_hosts_entry(struct evdns_base *base, const char *hostname,
- struct hosts_entry *find_after)
-{
- struct hosts_entry *e;
-
- if (find_after)
- e = TAILQ_NEXT(find_after, next);
- else
- e = TAILQ_FIRST(&base->hostsdb);
-
- for (; e; e = TAILQ_NEXT(e, next)) {
- if (!evutil_ascii_strcasecmp(e->hostname, hostname))
- return e;
- }
- return NULL;
-}
-
-static int
-evdns_getaddrinfo_fromhosts(struct evdns_base *base,
- const char *nodename, struct evutil_addrinfo *hints, ev_uint16_t port,
- struct evutil_addrinfo **res)
-{
- int n_found = 0;
- struct hosts_entry *e;
- struct evutil_addrinfo *ai=NULL;
- int f = hints->ai_family;
-
- EVDNS_LOCK(base);
- for (e = find_hosts_entry(base, nodename, NULL); e;
- e = find_hosts_entry(base, nodename, e)) {
- struct evutil_addrinfo *ai_new;
- ++n_found;
- if ((e->addr.sa.sa_family == AF_INET && f == PF_INET6) ||
- (e->addr.sa.sa_family == AF_INET6 && f == PF_INET))
- continue;
- ai_new = evutil_new_addrinfo(&e->addr.sa, e->addrlen, hints);
- if (!ai_new) {
- n_found = 0;
- goto out;
- }
- sockaddr_setport(ai_new->ai_addr, port);
- ai = evutil_addrinfo_append(ai, ai_new);
- }
- EVDNS_UNLOCK(base);
-out:
- if (n_found) {
- /* Note that we return an empty answer if we found entries for
- * this hostname but none were of the right address type. */
- *res = ai;
- return 0;
- } else {
- if (ai)
- evutil_freeaddrinfo(ai);
- return -1;
- }
-}
-
-struct evdns_getaddrinfo_request *
-evdns_getaddrinfo(struct evdns_base *dns_base,
- const char *nodename, const char *servname,
- const struct evutil_addrinfo *hints_in,
- evdns_getaddrinfo_cb cb, void *arg)
-{
- struct evdns_getaddrinfo_request *data;
- struct evutil_addrinfo hints;
- struct evutil_addrinfo *res = NULL;
- int err;
- int port = 0;
- int want_cname = 0;
-
- if (!dns_base) {
- dns_base = current_base;
- if (!dns_base) {
- log(EVDNS_LOG_WARN,
- "Call to getaddrinfo_async with no "
- "evdns_base configured.");
- cb(EVUTIL_EAI_FAIL, NULL, arg); /* ??? better error? */
- return NULL;
- }
- }
-
- /* If we _must_ answer this immediately, do so. */
- if ((hints_in && (hints_in->ai_flags & EVUTIL_AI_NUMERICHOST))) {
- res = NULL;
- err = evutil_getaddrinfo(nodename, servname, hints_in, &res);
- cb(err, res, arg);
- return NULL;
- }
-
- if (hints_in) {
- memcpy(&hints, hints_in, sizeof(hints));
- } else {
- memset(&hints, 0, sizeof(hints));
- hints.ai_family = PF_UNSPEC;
- }
-
- evutil_adjust_hints_for_addrconfig(&hints);
-
- /* Now try to see if we _can_ answer immediately. */
- /* (It would be nice to do this by calling getaddrinfo directly, with
- * AI_NUMERICHOST, on plaforms that have it, but we can't: there isn't
- * a reliable way to distinguish the "that wasn't a numeric host!" case
- * from any other EAI_NONAME cases.) */
- err = evutil_getaddrinfo_common(nodename, servname, &hints, &res, &port);
- if (err != EVUTIL_EAI_NEED_RESOLVE) {
- cb(err, res, arg);
- return NULL;
- }
-
- /* If there is an entry in the hosts file, we should give it now. */
- if (!evdns_getaddrinfo_fromhosts(dns_base, nodename, &hints, port, &res)) {
- cb(0, res, arg);
- return NULL;
- }
-
- /* Okay, things are serious now. We're going to need to actually
- * launch a request.
- */
- data = mm_calloc(1,sizeof(struct evdns_getaddrinfo_request));
- if (!data) {
- cb(EVUTIL_EAI_MEMORY, NULL, arg);
- return NULL;
- }
-
- memcpy(&data->hints, &hints, sizeof(data->hints));
- data->port = (ev_uint16_t)port;
- data->ipv4_request.type = DNS_IPv4_A;
- data->ipv6_request.type = DNS_IPv6_AAAA;
- data->user_cb = cb;
- data->user_data = arg;
- data->evdns_base = dns_base;
-
- want_cname = (hints.ai_flags & EVUTIL_AI_CANONNAME);
-
- /* If we are asked for a PF_UNSPEC address, we launch two requests in
- * parallel: one for an A address and one for an AAAA address. We
- * can't send just one request, since many servers only answer one
- * question per DNS request.
- *
- * Once we have the answer to one request, we allow for a short
- * timeout before we report it, to see if the other one arrives. If
- * they both show up in time, then we report both the answers.
- *
- * If too many addresses of one type time out or fail, we should stop
- * launching those requests. (XXX we don't do that yet.)
- */
-
- if (hints.ai_family != PF_INET6) {
- log(EVDNS_LOG_DEBUG, "Sending request for %s on ipv4 as %p",
- nodename, &data->ipv4_request);
-
- data->ipv4_request.r = evdns_base_resolve_ipv4(dns_base,
- nodename, 0, evdns_getaddrinfo_gotresolve,
- &data->ipv4_request);
- if (want_cname)
- data->ipv4_request.r->current_req->put_cname_in_ptr =
- &data->cname_result;
- }
- if (hints.ai_family != PF_INET) {
- log(EVDNS_LOG_DEBUG, "Sending request for %s on ipv6 as %p",
- nodename, &data->ipv6_request);
-
- data->ipv6_request.r = evdns_base_resolve_ipv6(dns_base,
- nodename, 0, evdns_getaddrinfo_gotresolve,
- &data->ipv6_request);
- if (want_cname)
- data->ipv6_request.r->current_req->put_cname_in_ptr =
- &data->cname_result;
- }
-
- evtimer_assign(&data->timeout, dns_base->event_base,
- evdns_getaddrinfo_timeout_cb, data);
-
- if (data->ipv4_request.r || data->ipv6_request.r) {
- return data;
- } else {
- mm_free(data);
- cb(EVUTIL_EAI_FAIL, NULL, arg);
- return NULL;
- }
-}
-
-void
-evdns_getaddrinfo_cancel(struct evdns_getaddrinfo_request *data)
-{
- EVDNS_LOCK(data->evdns_base);
- if (data->request_done) {
- EVDNS_UNLOCK(data->evdns_base);
- return;
- }
- event_del(&data->timeout);
- data->user_canceled = 1;
- if (data->ipv4_request.r)
- evdns_cancel_request(data->evdns_base, data->ipv4_request.r);
- if (data->ipv6_request.r)
- evdns_cancel_request(data->evdns_base, data->ipv6_request.r);
- EVDNS_UNLOCK(data->evdns_base);
-}
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