First pass at handling responses properly for retransmissions

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@3036 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/channels/chan_mgcp.c b/channels/chan_mgcp.c
index ea29918..b86df39 100755 (executable)
--- a/channels/chan_mgcp.c
+++ b/channels/chan_mgcp.c
@@ -280,6 +280,16 @@ struct mgcp_message {
        unsigned char buf[0];
 };
 
+#define RESPONSE_TIMEOUT 30    /* in seconds */
+
+struct mgcp_response {
+       time_t whensent;
+       int len;
+       int seqno;
+       struct mgcp_response *next;
+       unsigned char buf[0];
+};
+
 #define MAX_SUBS 2
 
 #define SUB_REAL 0
@@ -405,6 +415,7 @@ static struct mgcp_gateway {
        ast_mutex_t msgs_lock;     /* SC: queue lock */  
     int retransid;             /* SC: retrans timer id */
     int delme;                 /* SC: needed for reload */
+       struct mgcp_response *responses;
        struct mgcp_gateway *next;
 } *gateways;
 
@@ -478,6 +489,19 @@ static int __mgcp_xmit(struct mgcp_gateway *gw, char *data, int len)
        return res;
 }
 
+static int resend_response(struct mgcp_subchannel *sub, struct mgcp_response *resp)
+{
+    struct mgcp_endpoint *p = sub->parent;
+       int res;
+       if (mgcpdebug) {
+               ast_verbose("Retransmitting:\n%s\n to %s:%d\n", resp->buf, inet_ntoa(p->parent->addr.sin_addr), ntohs(p->parent->addr.sin_port));
+    }
+       res = __mgcp_xmit(p->parent, resp->buf, resp->len);
+       if (res > 0)
+               res = 0;
+       return res;
+}
+
 static int send_response(struct mgcp_subchannel *sub, struct mgcp_request *req)
 {
     struct mgcp_endpoint *p = sub->parent;
@@ -1774,7 +1798,20 @@ static int transmit_response(struct mgcp_subchannel *sub, char *msg, struct mgcp
 {
        struct mgcp_request resp;
     struct mgcp_endpoint *p = sub->parent;
+       struct mgcp_response *mgr;
        respprep(&resp, p, msg, req, msgrest);
+       mgr = malloc(sizeof(struct mgcp_response) + resp.len + 1);
+       if (mgr) {
+               /* Store MGCP response in case we have to retransmit */
+               memset(mgr, 0, sizeof(struct mgcp_response));
+               sscanf(req->identifier, "%d", &mgr->seqno);
+               time(&mgr->whensent);
+               mgr->len = resp.len;
+               memcpy(mgr->buf, resp.data, resp.len);
+               mgr->buf[resp.len] = '\0';
+               mgr->next = p->parent->responses;
+               p->parent->responses = mgr->next;
+       }
        return send_response(sub, &resp);
 }
 
@@ -3036,6 +3073,38 @@ static int handle_request(struct mgcp_subchannel *sub, struct mgcp_request *req,
        return 0;
 }
 
+static int find_and_retrans(struct mgcp_subchannel *sub, struct mgcp_request *req)
+{
+       int seqno=0;
+       time_t now;
+       struct mgcp_response *prev = NULL, *cur, *next, *answer=NULL;
+       time(&now);
+       if (sscanf(req->identifier, "%d", &seqno) != 1) 
+               seqno = 0;
+       cur = sub->parent->parent->responses;
+       while(cur) {
+               next = cur->next;
+               if (now - cur->whensent > RESPONSE_TIMEOUT) {
+                       /* Delete this entry */
+                       if (prev)
+                               prev->next = next;
+                       else
+                               sub->parent->parent->responses = next;
+                       free(cur);
+               } else {
+                       if (seqno == cur->seqno)
+                               answer = cur;
+                       prev = cur;
+               }
+               cur = next;
+       }
+       if (answer) {
+               resend_response(sub, answer);
+               return 1;
+       }
+       return 0;
+}
+
 static int mgcpsock_read(int *id, int fd, short events, void *ignore)
 {
        struct mgcp_request req;
@@ -3079,7 +3148,7 @@ static int mgcpsock_read(int *id, int fd, short events, void *ignore)
             ast_mutex_lock(&gw->msgs_lock);
             for (prev = NULL, cur = gw->msgs; cur; prev = cur, cur = cur->next) {
                 if (cur->seqno == ident) {
-                    ast_log(LOG_DEBUG, "Got response back on tansaction %d\n", ident);
+                    ast_log(LOG_DEBUG, "Got response back on transaction %d\n", ident);
                     if (prev)
                         prev->next = cur->next;
                     else 
@@ -3115,8 +3184,10 @@ static int mgcpsock_read(int *id, int fd, short events, void *ignore)
                /* Process request, with iflock held */
                sub = find_subchannel(req.endpoint, 0, &sin);
                if (sub) {
-            /* pass the request off to the currently mastering subchannel */
-                       handle_request(sub, &req, &sin);
+                       /* look first to find a matching response in the queue */
+                       if (!find_and_retrans(sub, &req))
+                   /* pass the request off to the currently mastering subchannel */
+                               handle_request(sub, &req, &sin);
                }
        }
        return 1;