--- /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));
+
+ 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);
+
+ 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->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(PF_INET, 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 (!base) {
+ /* This redundancy is silly; can we fix it? (Not for 2.0) XXXX */
+ base = handle->base;
+ if (!base && handle->current_req)
+ 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);
+ 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);
+ 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);
+}
projects / netatalk.git / blobdiff