Fix logic regarding when to perform an SRV lookup for outgoing REGISTER requests

With this fix, we only will perform an SRV lookup at the following times:

* The first time we register with a remote registrar
* If we send a REGISTER but do not receive a response
* If the sendto() function returns an error

While I wrote the patch that fixes this issue, a huge amount of credit is due
to Brett Bryant, who wrote the initial patch on which I based this one.

(closes issue #12312)
Reported by: jrast
Patches:
      12312.patch uploaded by putnopvut (license 60)
Tested by: blitzrage

Review: http://reviewboard.digium.com/r/132/

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@173770 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/channels/chan_sip.c b/channels/chan_sip.c
index c08d84a5dc58985c8b82bc988be185010b9cbc36..d0575b51edc68975c70d9047840a961cc499450f 100644 (file)
--- a/channels/chan_sip.c
+++ b/channels/chan_sip.c
@@ -1174,6 +1174,7 @@ struct sip_registry {
        int refresh;                    /*!< How often to refresh */
        struct sip_pvt *call;           /*!< create a sip_pvt structure for each outbound "registration dialog" in progress */
        enum sipregistrystate regstate; /*!< Registration state (see above) */
+       unsigned int needdns:1; /*!< Set if we need a new dns lookup before we try to transmit */
        time_t regtime;         /*!< Last succesful registration time */
        int callid_valid;               /*!< 0 means we haven't chosen callid for this registry yet. */
        unsigned int ocseq;             /*!< Sequence number we got to for REGISTERs for this registry */
@@ -1512,7 +1513,7 @@ static int respprep(struct sip_request *resp, struct sip_pvt *p, const char *msg
 static const struct sockaddr_in *sip_real_dst(const struct sip_pvt *p);
 static void build_via(struct sip_pvt *p);
 static int create_addr_from_peer(struct sip_pvt *r, struct sip_peer *peer);
-static int create_addr(struct sip_pvt *dialog, const char *opeer);
+static int create_addr(struct sip_pvt *dialog, const char *opeer, struct sockaddr_in *sin);
 static char *generate_random_string(char *buf, size_t size);
 static void build_callid_pvt(struct sip_pvt *pvt);
 static void build_callid_registry(struct sip_registry *reg, struct in_addr ourip, const char *fromdomain);
@@ -1800,7 +1801,14 @@ static int __sip_xmit(struct sip_pvt *p, char *data, int len)
                case ECONNREFUSED:      /* ICMP port unreachable */ 
                        res = XMIT_ERROR;       /* Don't bother with trying to transmit again */
                }
+
+               if (p->registry && p->registry->regstate < REG_STATE_REGISTERED) {
+                       AST_SCHED_DEL(sched, p->registry->timeout);
+                       p->registry->needdns = TRUE;
+                       p->registry->timeout = ast_sched_add(sched, 1, sip_reg_timeout, p->registry);
+               }
        }
+
        if (res != len)
                ast_log(LOG_WARNING, "sip_xmit of %p (len %d) to %s:%d returned %d: %s\n", data, len, ast_inet_ntoa(dst->sin_addr), ntohs(dst->sin_port), res, strerror(errno));
        return res;
@@ -2907,7 +2915,7 @@ static int create_addr_from_peer(struct sip_pvt *dialog, struct sip_peer *peer)
 /*! \brief create address structure from peer name
  *      Or, if peer not found, find it in the global DNS 
  *      returns TRUE (-1) on failure, FALSE on success */
-static int create_addr(struct sip_pvt *dialog, const char *opeer)
+static int create_addr(struct sip_pvt *dialog, const char *opeer, struct sockaddr_in *sin)
 {
        struct hostent *hp;
        struct ast_hostent ahp;
@@ -2934,27 +2942,40 @@ static int create_addr(struct sip_pvt *dialog, const char *opeer)
                ASTOBJ_UNREF(p, sip_destroy_peer);
                return res;
        }
-       hostn = peer;
-       portno = port ? atoi(port) : STANDARD_SIP_PORT;
-       if (srvlookup) {
-               char service[MAXHOSTNAMELEN];
-               int tportno;
-               int ret;
+       
+       ast_string_field_set(dialog, tohost, peer);
 
-               snprintf(service, sizeof(service), "_sip._udp.%s", peer);
-               ret = ast_get_srv(NULL, host, sizeof(host), &tportno, service);
-               if (ret > 0) {
-                       hostn = host;
-                       portno = tportno;
+       if (sin) {
+               memcpy(&dialog->sa.sin_addr, &sin->sin_addr, sizeof(dialog->sa.sin_addr));
+               if (!sin->sin_port) {
+                       if (ast_strlen_zero(port) || sscanf(port, "%u", &portno) != 1) {
+                               portno = STANDARD_SIP_PORT;
+                       }
+               } else {
+                       portno = ntohs(sin->sin_port);
                }
+       } else {
+               hostn = peer;
+               portno = port ? atoi(port) : STANDARD_SIP_PORT;
+               if (srvlookup) {
+                       char service[MAXHOSTNAMELEN];
+                       int tportno;
+                       int ret;
+
+                       snprintf(service, sizeof(service), "_sip._udp.%s", peer);
+                       ret = ast_get_srv(NULL, host, sizeof(host), &tportno, service);
+                       if (ret > 0) {
+                               hostn = host;
+                               portno = tportno;
+                       }
+               }
+               hp = ast_gethostbyname(hostn, &ahp);
+               if (!hp) {
+                       ast_log(LOG_WARNING, "No such host: %s\n", peer);
+                       return -1;
+               }
+               memcpy(&dialog->sa.sin_addr, hp->h_addr, sizeof(dialog->sa.sin_addr));
        }
-       hp = ast_gethostbyname(hostn, &ahp);
-       if (!hp) {
-               ast_log(LOG_WARNING, "No such host: %s\n", peer);
-               return -1;
-       }
-       ast_string_field_set(dialog, tohost, peer);
-       memcpy(&dialog->sa.sin_addr, hp->h_addr, sizeof(dialog->sa.sin_addr));
        dialog->sa.sin_port = htons(portno);
        dialog->recv = dialog->sa;
        return 0;
@@ -4814,6 +4835,7 @@ static int sip_register(char *value, int lineno)
        reg->portno = portnum;
        reg->callid_valid = FALSE;
        reg->ocseq = INITIAL_CSEQ;
+       reg->needdns = TRUE;
        ASTOBJ_CONTAINER_LINK(&regl, reg);      /* Add the new registry entry to the list */
        ASTOBJ_UNREF(reg,sip_registry_destroy);
        return 0;
@@ -7644,6 +7666,7 @@ static int sip_reg_timeout(const void *data)
        } else {
                r->regstate = REG_STATE_UNREGISTERED;
                r->timeout = -1;
+               r->needdns = TRUE;
                res=transmit_register(r, SIP_REGISTER, NULL, NULL);
        }
        manager_event(EVENT_FLAG_SYSTEM, "Registry", "ChannelDriver: SIP\r\nUsername: %s\r\nDomain: %s\r\nStatus: %s\r\n", r->username, r->hostname, regstate2str(r->regstate));
@@ -7692,8 +7715,9 @@ static int transmit_register(struct sip_registry *r, int sipmethod, const char *
                }
                if (!ast_test_flag(&p->flags[0], SIP_NO_HISTORY))
                        append_history(p, "RegistryInit", "Account: %s@%s", r->username, r->hostname);
-               /* Find address to hostname */
-               if (create_addr(p, r->hostname)) {
+               /* Find address to hostname if we haven't tried to connect
+                * or a connection error has occurred */
+               if (create_addr(p, r->hostname, r->needdns ? NULL : &r->us)) {
                        /* we have what we hope is a temporary network error,
                         * probably DNS.  We need to reschedule a registration try */
                        sip_destroy(p);
@@ -7708,6 +7732,10 @@ static int transmit_register(struct sip_registry *r, int sipmethod, const char *
                        r->regattempts++;
                        return 0;
                }
+               if (r->needdns) {
+                       memcpy(&r->us, &p->sa, sizeof(r->us));
+               }
+               r->needdns = FALSE;
                /* Copy back Call-ID in case create_addr changed it */
                ast_string_field_set(r, callid, p->callid);
                if (r->portno) {
@@ -11563,7 +11591,7 @@ static int sip_notify(int fd, int argc, char *argv[])
                        return RESULT_FAILURE;
                }
 
-               if (create_addr(p, argv[i])) {
+               if (create_addr(p, argv[i], NULL)) {
                        /* Maybe they're not registered, etc. */
                        sip_destroy(p);
                        ast_cli(fd, "Could not create address for '%s'\n", argv[i]);
@@ -16682,7 +16710,7 @@ static struct ast_channel *sip_request_call(const char *type, int format, void *
                host = tmp;
        }
 
-       if (create_addr(p, host)) {
+       if (create_addr(p, host, NULL)) {
                *cause = AST_CAUSE_UNREGISTERED;
                if (option_debug > 2)
                        ast_log(LOG_DEBUG, "Cant create SIP call - target device not registred\n");