]> arthur.barton.de Git - ngircd-alex.git/blobdiff - src/ngircd/resolve.c
New configuration option "NoIdent" to disable IDENT lookups
[ngircd-alex.git] / src / ngircd / resolve.c
index 723880f662ac846e53f3e74718d9dca75bfeb4dd..999ef9906df241f3c3d195524df8fb86c1082907 100644 (file)
@@ -14,7 +14,7 @@
 
 #include "portab.h"
 
-static char UNUSED id[] = "$Id: resolve.c,v 1.18 2005/09/02 21:47:30 fw Exp $";
+static char UNUSED id[] = "$Id: resolve.c,v 1.29 2008/02/26 22:04:17 fw Exp $";
 
 #include "imp.h"
 #include <assert.h>
@@ -24,7 +24,6 @@ static char UNUSED id[] = "$Id: resolve.c,v 1.18 2005/09/02 21:47:30 fw Exp $";
 #include <unistd.h>
 #include <sys/socket.h>
 #include <netinet/in.h>
-#include <arpa/inet.h>
 #include <netdb.h>
 
 #ifdef IDENTAUTH
@@ -42,321 +41,506 @@ static char UNUSED id[] = "$Id: resolve.c,v 1.18 2005/09/02 21:47:30 fw Exp $";
 #include "io.h"
 
 
-#ifdef IDENTAUTH
-static void Do_ResolveAddr PARAMS(( struct sockaddr_in *Addr, int Sock, int w_fd ));
-#else
-static void Do_ResolveAddr PARAMS(( struct sockaddr_in *Addr, int w_fd ));
-#endif
+static void Do_ResolveAddr PARAMS(( const ng_ipaddr_t *Addr, int Sock, int w_fd ));
+static void Do_ResolveName PARAMS(( const char *Host, int w_fd ));
+static bool register_callback PARAMS((RES_STAT *s, void (*cbfunc)(int, short)));
 
-static void Do_ResolveName PARAMS(( char *Host, int w_fd ));
-
-#ifdef h_errno
-static char *Get_Error PARAMS(( int H_Error ));
+#ifdef WANT_IPV6
+extern bool Conf_ConnectIPv4;
+extern bool Conf_ConnectIPv6;
 #endif
 
-static RES_STAT *New_Res_Stat PARAMS(( void ));
+static pid_t
+Resolver_fork(int *pipefds)
+{
+       pid_t pid;
 
+       if (pipe(pipefds) != 0) {
+                Log( LOG_ALERT, "Resolver: Can't create output pipe: %s!", strerror( errno ));
+                return -1;
+       }
 
-static void
-cb_resolver(int fd, short unused) {
-       (void) unused;  /* shut up compiler warning */
-       Read_Resolver_Result(fd);
+       pid = fork();
+       switch(pid) {
+               case -1:
+                       Log( LOG_CRIT, "Resolver: Can't fork: %s!", strerror( errno ));
+                       close(pipefds[0]);
+                       close(pipefds[1]);
+                       return -1;
+               case 0: /* child */
+                       close(pipefds[0]);
+                       Log_Init_Resolver( );
+                       return 0;
+       }
+       /* parent */
+       close(pipefds[1]);
+       return pid; 
 }
 
 
-#ifdef IDENTAUTH
-GLOBAL RES_STAT *
-Resolve_Addr( struct sockaddr_in *Addr, int Sock )
-#else
-GLOBAL RES_STAT *
-Resolve_Addr( struct sockaddr_in *Addr )
-#endif
+/**
+ * Resolve IP (asynchronous!).
+ */
+GLOBAL bool
+Resolve_Addr(RES_STAT * s, const ng_ipaddr_t *Addr, int identsock,
+            void (*cbfunc) (int, short))
 {
-       /* Resolve IP (asynchronous!). On errors, e.g. if the child process
-        * can't be forked, this functions returns NULL. */
+       int pipefd[2];
+       pid_t pid;
 
-       RES_STAT *s;
-       int pid;
+       assert(s != NULL);
 
-       s = New_Res_Stat( );
-       if( ! s ) return NULL;
+       pid = Resolver_fork(pipefd);
+       if (pid > 0) {
+               Log(LOG_DEBUG, "Resolver for %s created (PID %d).", ng_ipaddr_tostr(Addr), pid);
 
-       /* For sub-process */
-       pid = fork( );
-       if( pid > 0 )
-       {
-               close( s->pipe[1] );
-               /* Main process */
-               Log( LOG_DEBUG, "Resolver for %s created (PID %d).", inet_ntoa( Addr->sin_addr ), pid );
-               if (!io_setnonblock( s->pipe[0] )) {
-                       Log( LOG_DEBUG, "Could not set Non-Blocking mode for pipefd %d", s->pipe[0] );
-                       goto out;
-               }
-               if (!io_event_create( s->pipe[0], IO_WANTREAD, cb_resolver )) {
-                       Log( LOG_DEBUG, "Could not add pipefd %dto event watchlist: %s",
-                                                               s->pipe[0], strerror(errno) );
-                       goto out;
-               }
                s->pid = pid;
-               return s;
-       }
-       else if( pid == 0 )
-       {
-               close( s->pipe[0] );
+               s->resolver_fd = pipefd[0];
+               return register_callback(s, cbfunc);
+       } else if( pid == 0 ) {
                /* Sub process */
-               Log_Init_Resolver( );
-#ifdef IDENTAUTH
-               Do_ResolveAddr( Addr, Sock, s->pipe[1] );
-#else
-               Do_ResolveAddr( Addr, s->pipe[1] );
-#endif
+               Do_ResolveAddr( Addr, identsock, pipefd[1]);
                Log_Exit_Resolver( );
-               exit( 0 );
+               exit(0);
        }
-       
-       Log( LOG_CRIT, "Resolver: Can't fork: %s!", strerror( errno ));
-
-out: /* Error! */
-       close( s->pipe[0] );
-       close( s->pipe[1] );
-       free( s );
-return NULL;
+       return false;
 } /* Resolve_Addr */
 
 
-GLOBAL RES_STAT *
-Resolve_Name( char *Host )
+/**
+ * Resolve hostname (asynchronous!).
+ */
+GLOBAL bool
+Resolve_Name( RES_STAT *s, const char *Host, void (*cbfunc)(int, short))
 {
-       /* Resolve hostname (asynchronous!). On errors, e.g. if the child
-        * process can't be forked, this functions returns NULL. */
-
-       RES_STAT *s;
-       int pid;
+       int pipefd[2];
+       pid_t pid;
 
-       s = New_Res_Stat( );
-       if( ! s ) return NULL;
+       assert(s != NULL);
 
-       /* Fork sub-process */
-       pid = fork( );
-       if( pid > 0 )
-       {
-               close( s->pipe[1] );
+       pid = Resolver_fork(pipefd);
+       if (pid > 0) {
                /* Main process */
+#ifdef DEBUG
                Log( LOG_DEBUG, "Resolver for \"%s\" created (PID %d).", Host, pid );
-               if (!io_setnonblock( s->pipe[0] )) {
-                       Log( LOG_DEBUG, "Could not set Non-Blocking mode for pipefd %d", s->pipe[0] );
-                       goto out;
-               }
-               if (!io_event_create( s->pipe[0], IO_WANTREAD, cb_resolver )) {
-                       Log( LOG_DEBUG, "Could not add pipefd %dto event watchlist: %s",
-                                                               s->pipe[0], strerror(errno) );
-                       goto out;
-               }
+#endif
                s->pid = pid;
-               return s;
-       }
-       else if( pid == 0 )
-       {
-               close( s->pipe[0] );
+               s->resolver_fd = pipefd[0];
+               return register_callback(s, cbfunc);
+       } else if( pid == 0 ) {
                /* Sub process */
-               Log_Init_Resolver( );
-               Do_ResolveName( Host, s->pipe[1] );
+               Do_ResolveName(Host, pipefd[1]);
                Log_Exit_Resolver( );
-               exit( 0 );
+               exit(0);
        }
+       return false;
+} /* Resolve_Name */
 
-       Log( LOG_CRIT, "Resolver: Can't fork: %s!", strerror( errno ));
 
-out: /* Error! */
-       close( s->pipe[0] );
-       close( s->pipe[1] );
-       free( s );
-       return NULL;
-} /* Resolve_Name */
+GLOBAL void
+Resolve_Init(RES_STAT *s)
+{
+       assert(s != NULL);
+       s->resolver_fd = -1;
+       s->pid = 0;
+}
 
 
-#ifdef IDENTAUTH
+#ifndef WANT_IPV6
+#ifdef h_errno
+static char *
+Get_Error( int H_Error )
+{
+       /* Get error message for H_Error */
+       switch( H_Error ) {
+       case HOST_NOT_FOUND:
+               return "host not found";
+       case NO_DATA:
+               return "name valid but no IP address defined";
+       case NO_RECOVERY:
+               return "name server error";
+       case TRY_AGAIN:
+               return "name server temporary not available";
+       }
+       return "unknown error";
+}
+#endif /* h_errno */
+#endif /* WANT_IPV6 */
+
+
+/* Do "IDENT" (aka "AUTH") lookup and append result to resolved_addr array */
 static void
-Do_ResolveAddr( struct sockaddr_in *Addr, int Sock, int w_fd )
+Do_IdentQuery(int identsock, array *resolved_addr)
+{
+#ifdef IDENTAUTH
+       char *res;
+
+       if (identsock < 0)
+               return;
+
+#ifdef DEBUG
+       Log_Resolver(LOG_DEBUG, "Doing IDENT lookup on socket %d ...", identsock);
+#endif
+       res = ident_id( identsock, 10 );
+#ifdef DEBUG
+       Log_Resolver(LOG_DEBUG, "Ok, IDENT lookup on socket %d done: \"%s\"",
+                                               identsock, res ? res : "(NULL)" );
+#endif
+       if (!res) /* no result */
+               return;
+       if (!array_cats(resolved_addr, res))
+               Log_Resolver(LOG_WARNING, "Resolver: Cannot copy IDENT result: %s!", strerror(errno));
+
+       free(res);
 #else
-static void
-Do_ResolveAddr( struct sockaddr_in *Addr, int w_fd )
+       (void) identsock;
+       (void) resolved_addr;
 #endif
+}
+
+
+/**
+ * perform reverse DNS lookup and put result string into resbuf.
+ * If no hostname could be obtained, this function stores the string representation of
+ * the IP address in resbuf and returns false.
+ * @param IpAddr ip address to resolve
+ * @param resbuf result buffer to store DNS name/string representation of ip address
+ * @reslen size of result buffer (must be >= NGT_INET_ADDRSTRLEN)
+ * @return true if reverse lookup successful, false otherwise
+ */
+static bool
+ReverseLookup(const ng_ipaddr_t *IpAddr, char *resbuf, size_t reslen)
 {
-       /* Resolver sub-process: resolve IP address and write result into
-        * pipe to parent. */
+       char tmp_ip_str[NG_INET_ADDRSTRLEN];
+       const char *errmsg;
+#ifdef HAVE_GETNAMEINFO
+       static const char funcname[]="getnameinfo";
+       int res;
+
+       *resbuf = 0;
 
-       char hostname[HOST_LEN];
-       char ipstr[HOST_LEN];
+       res = getnameinfo((struct sockaddr *) IpAddr, ng_ipaddr_salen(IpAddr),
+                               resbuf, reslen, NULL, 0, NI_NAMEREQD);
+       if (res == 0)
+               return true;
+
+       if (res == EAI_SYSTEM)
+               errmsg = strerror(errno);
+       else
+               errmsg = gai_strerror(res);
+#else
+       const struct sockaddr_in *Addr = (const struct sockaddr_in *) IpAddr;
        struct hostent *h;
-       size_t len;
-       struct in_addr *addr;
-       char *ntoaptr;
-#ifdef IDENTAUTH
-       char *res;
+       static const char funcname[]="gethostbyaddr";
+
+       h = gethostbyaddr((char *)&Addr->sin_addr, sizeof(Addr->sin_addr), AF_INET);
+       if (h) {
+               if (strlcpy(resbuf, h->h_name, reslen) < reslen)
+                       return true;
+               errmsg = "hostname too long";
+       } else {
+# ifdef h_errno
+               errmsg = Get_Error(h_errno);
+# else
+               errmsg = "unknown error";
+# endif /* h_errno */
+       }
+#endif /* HAVE_GETNAMEINFO */
+
+       assert(errmsg);
+       assert(reslen >= NG_INET_ADDRSTRLEN);
+       ng_ipaddr_tostr_r(IpAddr, tmp_ip_str);
+
+       Log_Resolver(LOG_WARNING, "%s: Can't resolve address \"%s\": %s",
+                               funcname, tmp_ip_str, errmsg);
+       strlcpy(resbuf, tmp_ip_str, reslen);
+       return false;
+}
+
+
+/**
+ * perform DNS lookup of given host name and fill IpAddr with a list of
+ * ip addresses associated with that name.
+ * ip addresses found are stored in the "array *IpAddr" argument (type ng_ipaddr_t)
+ * @param hostname The domain name to look up.
+ * @param IpAddr pointer to empty and initialized array to store results
+ * @return true if lookup successful, false if domain name not found
+ */
+static bool
+ForwardLookup(const char *hostname, array *IpAddr)
+{
+       ng_ipaddr_t addr;
+
+#ifdef HAVE_GETADDRINFO
+       int res;
+       struct addrinfo *a, *ai_results;
+       static struct addrinfo hints;
+
+#ifndef WANT_IPV6
+       hints.ai_family = AF_INET;
+#endif
+#ifdef AI_ADDRCONFIG   /* glibc has this, but not e.g. netbsd 4.0 */
+       hints.ai_flags = AI_ADDRCONFIG;
 #endif
+       hints.ai_socktype = SOCK_STREAM;
+       hints.ai_protocol = IPPROTO_TCP;
 
-       /* Resolve IP address */
-#ifdef DEBUG
-       Log_Resolver( LOG_DEBUG, "Now resolving %s ...", inet_ntoa( Addr->sin_addr ));
+#ifdef WANT_IPV6
+       assert(Conf_ConnectIPv6 || Conf_ConnectIPv4);
+
+       if (!Conf_ConnectIPv6)
+               hints.ai_family = AF_INET;
+       if (!Conf_ConnectIPv4)
+               hints.ai_family = AF_INET6;
 #endif
-       h = gethostbyaddr( (char *)&Addr->sin_addr, sizeof( Addr->sin_addr ), AF_INET );
+       res = getaddrinfo(hostname, NULL, &hints, &ai_results);
+       switch (res) {
+       case 0: break;
+       case EAI_SYSTEM:
+               Log_Resolver(LOG_WARNING, "Can't resolve \"%s\": %s", hostname, strerror(errno));
+               return false;
+       default:
+               Log_Resolver(LOG_WARNING, "Can't resolve \"%s\": %s", hostname, gai_strerror(res));
+               return false;
+       }
+
+       for (a = ai_results; a != NULL; a = a->ai_next) {
+               assert(a->ai_addrlen <= sizeof(addr));
+
+               if (a->ai_addrlen > sizeof(addr))
+                       continue;
+
+               memcpy(&addr, a->ai_addr, a->ai_addrlen);
+
+               if (!array_catb(IpAddr, (char *)&addr, sizeof(addr)))
+                       break;
+       }
+
+       freeaddrinfo(ai_results);
+       return a == NULL;
+#else
+       struct hostent *h = gethostbyname(hostname);
+
        if (!h) {
 #ifdef h_errno
-               Log_Resolver( LOG_WARNING, "Can't resolve address \"%s\": %s!", inet_ntoa( Addr->sin_addr ), Get_Error( h_errno ));
+               Log_Resolver(LOG_WARNING, "Can't resolve \"%s\": %s", hostname, Get_Error(h_errno));
 #else
-               Log_Resolver( LOG_WARNING, "Can't resolve address \"%s\"!", inet_ntoa( Addr->sin_addr ));
-#endif 
-               strlcpy( hostname, inet_ntoa( Addr->sin_addr ), sizeof( hostname ));
-       } else {
-               strlcpy( hostname, h->h_name, sizeof( hostname ));
-
-               h = gethostbyname( hostname );
-               if ( h ) {
-                       if (memcmp(h->h_addr, &Addr->sin_addr, sizeof (struct in_addr))) {
-                               addr = (struct in_addr*) h->h_addr;
-                               strlcpy(ipstr, inet_ntoa(*addr), sizeof ipstr); 
-                               ntoaptr = inet_ntoa( Addr->sin_addr );
-                               Log(LOG_WARNING,"Possible forgery: %s resolved to %s (which is at ip %s!)",
-                                                                               ntoaptr, hostname, ipstr);
-                               strlcpy( hostname, ntoaptr, sizeof hostname);
-                       }
-               } else {
-                       ntoaptr = inet_ntoa( Addr->sin_addr );
-                       Log(LOG_WARNING, "Possible forgery: %s resolved to %s (which has no ip address)",
-                                                                                       ntoaptr, hostname);
-                       strlcpy( hostname, ntoaptr, sizeof hostname);
-               }
+               Log_Resolver(LOG_WARNING, "Can't resolve \"%s\"", hostname);
+#endif
+               return false;
        }
-       Log_Resolver( LOG_DEBUG, "Ok, translated %s to \"%s\".", inet_ntoa( Addr->sin_addr ), hostname );
-
-       /* Write resolver result into pipe to parent */
-       len = strlen( hostname ); 
-       hostname[len] = '\n'; len++;
-       if( (size_t)write( w_fd, hostname, len ) != (size_t)len )
-       {
-               Log_Resolver( LOG_CRIT, "Resolver: Can't write to parent: %s!", strerror( errno ));
-               close( w_fd );
-               return;
+       memset(&addr, 0, sizeof(addr));
+
+       addr.sin4.sin_family = AF_INET;
+       memcpy(&addr.sin4.sin_addr, h->h_addr, sizeof(struct in_addr));
+
+       return array_copyb(IpAddr, (char *)&addr, sizeof(addr));
+#endif /* HAVE_GETADDRINFO */
+}
+
+
+static bool
+Addr_in_list(const array *resolved_addr, const ng_ipaddr_t *Addr)
+{
+       char tmp_ip_str[NG_INET_ADDRSTRLEN];
+       const ng_ipaddr_t *tmpAddrs = array_start(resolved_addr);
+       size_t len = array_length(resolved_addr, sizeof(*tmpAddrs));
+
+       assert(len > 0);
+       assert(tmpAddrs);
+
+       while (len > 0) {
+               if (ng_ipaddr_ipequal(Addr, tmpAddrs))
+                       return true;
+               tmpAddrs++;
+               len--;
+       }
+       /* failed; print list of addresses */
+       ng_ipaddr_tostr_r(Addr, tmp_ip_str);
+       len = array_length(resolved_addr, sizeof(*tmpAddrs));
+       tmpAddrs = array_start(resolved_addr);
+
+       while (len > 0) {
+               Log_Resolver(LOG_WARNING, "Address mismatch: %s != %s",
+                       tmp_ip_str, ng_ipaddr_tostr(tmpAddrs));
+               tmpAddrs++;
+               len--;
        }
 
-#ifdef IDENTAUTH
-       /* Do "IDENT" (aka "AUTH") lookup and write result to parent */
-       Log_Resolver( LOG_DEBUG, "Doing IDENT lookup on socket %d ...", Sock );
-       res = ident_id( Sock, 10 );
-       Log_Resolver( LOG_DEBUG, "Ok, IDENT lookup on socket %d done: \"%s\"", Sock, res ? res : "" );
-
-       /* Write IDENT result into pipe to parent */
-       if (res) {
-               len = strlen(res);
-               res[len] = '\n';
-               len++;
-       } else len = 1;
-
-       if( (size_t)write( w_fd, res ? res : "\n", len ) != (size_t)len )
-       {
-               Log_Resolver( LOG_CRIT, "Resolver: Can't write to parent (IDENT): %s!", strerror( errno ));
-               close( w_fd );
+       return false;
+}
+
+
+static void
+Log_Forgery_NoIP(const char *ip, const char *host)
+{
+       Log_Resolver(LOG_WARNING, "Possible forgery: %s resolved to %s "
+               "(which has no ip address)", ip, host);
+}
+
+static void
+Log_Forgery_WrongIP(const char *ip, const char *host)
+{
+       Log_Resolver(LOG_WARNING,"Possible forgery: %s resolved to %s "
+               "(which points to different address)", ip, host);
+}
+
+
+static void
+ArrayWrite(int fd, const array *a)
+{
+       size_t len = array_bytes(a);
+       const char *data = array_start(a);
+
+       assert(data);
+
+       if( (size_t)write(fd, data, len) != len )
+               Log_Resolver( LOG_CRIT, "Resolver: Can't write to parent: %s!",
+                                                       strerror(errno));
+}
+
+
+static void
+Do_ResolveAddr(const ng_ipaddr_t *Addr, int identsock, int w_fd)
+{
+       /* Resolver sub-process: resolve IP address and write result into
+        * pipe to parent. */
+       char hostname[CLIENT_HOST_LEN];
+       char tmp_ip_str[NG_INET_ADDRSTRLEN];
+       size_t len;
+       array resolved_addr;
+
+       array_init(&resolved_addr);
+       ng_ipaddr_tostr_r(Addr, tmp_ip_str);
+#ifdef DEBUG
+       Log_Resolver(LOG_DEBUG, "Now resolving %s ...", tmp_ip_str);
+#endif
+       if (!ReverseLookup(Addr, hostname, sizeof(hostname)))
+               goto dns_done;
+
+       if (ForwardLookup(hostname, &resolved_addr)) {
+               if (!Addr_in_list(&resolved_addr, Addr)) {
+                       Log_Forgery_WrongIP(tmp_ip_str, hostname);
+                       strlcpy(hostname, tmp_ip_str, sizeof(hostname));
+               }
+       } else {
+               Log_Forgery_NoIP(tmp_ip_str, hostname);
+               strlcpy(hostname, tmp_ip_str, sizeof(hostname));
        }
-       free( res );
+#ifdef DEBUG
+       Log_Resolver(LOG_DEBUG, "Ok, translated %s to \"%s\".", tmp_ip_str, hostname);
 #endif
+ dns_done:
+       len = strlen(hostname);
+       hostname[len] = '\n';
+       if (!array_copyb(&resolved_addr, hostname, ++len)) {
+               Log_Resolver(LOG_CRIT, "Resolver: Can't copy resolved name: %s!", strerror(errno));
+               array_free(&resolved_addr);
+               return;
+       }
+
+       Do_IdentQuery(identsock, &resolved_addr);
+
+       ArrayWrite(w_fd, &resolved_addr);
+
+       array_free(&resolved_addr);
 } /* Do_ResolveAddr */
 
 
 static void
-Do_ResolveName( char *Host, int w_fd )
+Do_ResolveName( const char *Host, int w_fd )
 {
        /* Resolver sub-process: resolve name and write result into pipe
         * to parent. */
+       array IpAddrs;
+#ifdef DEBUG
+       ng_ipaddr_t *addr;
+       size_t len;
+#endif
+       Log_Resolver(LOG_DEBUG, "Now resolving \"%s\" ...", Host);
 
-       char ip[16];
-       struct hostent *h;
-       struct in_addr *addr;
-       int len;
-
-       Log_Resolver( LOG_DEBUG, "Now resolving \"%s\" ...", Host );
-
+       array_init(&IpAddrs);
        /* Resolve hostname */
-       h = gethostbyname( Host );
-       if( h )
-       {
-               addr = (struct in_addr *)h->h_addr;
-               strlcpy( ip, inet_ntoa( *addr ), sizeof( ip ));
+       if (!ForwardLookup(Host, &IpAddrs)) {
+               close(w_fd);
+               return;
        }
-       else
-       {
-#ifdef h_errno
-               Log_Resolver( LOG_WARNING, "Can't resolve \"%s\": %s!", Host, Get_Error( h_errno ));
-#else
-               Log_Resolver( LOG_WARNING, "Can't resolve \"%s\"!", Host );
-#endif
-               ip[0] = '\0';
+#ifdef DEBUG
+       len = array_length(&IpAddrs, sizeof(*addr));
+       assert(len > 0);
+       addr = array_start(&IpAddrs);
+       assert(addr);
+       for (; len > 0; --len,addr++) {
+               Log_Resolver(LOG_DEBUG, "translated \"%s\" to %s.",
+                                       Host, ng_ipaddr_tostr(addr));
        }
-       if( ip[0] ) Log_Resolver( LOG_DEBUG, "Ok, translated \"%s\" to %s.", Host, ip );
-
+#endif
        /* Write result into pipe to parent */
-       len = strlen( ip );
-       ip[len] = '\n'; len++;
-       if( (size_t)write( w_fd, ip, len ) != (size_t)len )
-       {
-               Log_Resolver( LOG_CRIT, "Resolver: Can't write to parent: %s!", strerror( errno ));
-               close( w_fd );
-       }
-} /* Do_ResolveName */
+       ArrayWrite(w_fd, &IpAddrs);
 
+       array_free(&IpAddrs);
+} /* Do_ResolveName */
 
-#ifdef h_errno
 
-static char *
-Get_Error( int H_Error )
+static bool
+register_callback( RES_STAT *s, void (*cbfunc)(int, short))
 {
-       /* Get error message for H_Error */
+       assert(cbfunc != NULL);
+       assert(s != NULL);
+       assert(s->resolver_fd >= 0);
+
+       if (io_setnonblock(s->resolver_fd) &&
+               io_event_create(s->resolver_fd, IO_WANTREAD, cbfunc))
+                       return true;
+
+       Log( LOG_CRIT, "Resolver: Could not register callback function: %s!", strerror(errno));
+       close(s->resolver_fd);
+       Resolve_Init(s);
+       return false;
+}
 
-       switch( H_Error )
-       {
-               case HOST_NOT_FOUND:
-                       return "host not found";
-               case NO_DATA:
-                       return "name valid but no IP address defined";
-               case NO_RECOVERY:
-                       return "name server error";
-               case TRY_AGAIN:
-                       return "name server temporary not available";
-               default:
-                       return "unknown error";
-       }
-} /* Get_Error */
 
-#endif
+GLOBAL bool
+Resolve_Shutdown( RES_STAT *s)
+{
+       bool ret = false;
 
+       assert(s != NULL);
+       assert(s->resolver_fd >= 0);
 
-static RES_STAT *
-New_Res_Stat( void )
-{
-       RES_STAT *s;
-
-       /* Allocate memory */
-       s = (RES_STAT *)malloc( sizeof( RES_STAT ));
-       if( ! s )
-       {
-               Log( LOG_EMERG, "Resolver: Can't allocate memory! [Resolve_Addr]" );
-               return NULL;
-       }
+       if (s->resolver_fd >= 0)
+               ret = io_close(s->resolver_fd);
 
-       /* Initialize pipe for result */
-       if( pipe( s->pipe ) != 0 )
-       {
-               free( s );
-               Log( LOG_ALERT, "Resolver: Can't create output pipe: %s!", strerror( errno ));
-               return NULL;
-       }
+       Resolve_Init(s);
+       return ret;
+}
 
-       s->stage = 0;
-       array_init(&s->buffer);
-       s->pid = -1;
 
-       return s;
-} /* New_Res_Stat */
+/**
+ * Read result of resolver sub-process from pipe
+ */
+GLOBAL size_t
+Resolve_Read( RES_STAT *s, void* readbuf, size_t buflen)
+{
+       ssize_t bytes_read;
+
+       assert(buflen > 0);
 
+       /* Read result from pipe */
+       bytes_read = read(s->resolver_fd, readbuf, buflen);
+       if (bytes_read < 0) {
+               if (errno == EAGAIN)
+                       return 0;
 
+               Log( LOG_CRIT, "Resolver: Can't read result: %s!", strerror(errno));
+               bytes_read = 0;
+       }
+#ifdef DEBUG
+       else if (bytes_read == 0)
+               Log( LOG_DEBUG, "Resolver: Can't read result: EOF");
+#endif
+       Resolve_Shutdown(s);
+       return (size_t)bytes_read;
+}
 /* -eof- */
+