add a bit of comment on what build_route does,

plus minor code simplification.

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@31895 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/channels/chan_sip.c b/channels/chan_sip.c
index 0d1c828df3bfaa5f2c2df1528b80ae06cb3a6739..b54ace7e6d7fdbe654d6f6c15a359753249e3a82 100644 (file)
--- a/channels/chan_sip.c
+++ b/channels/chan_sip.c
@@ -6622,7 +6622,11 @@ static void build_route(struct sip_pvt *p, struct sip_request *req, int backward
        
        p->route_persistant = backwards;
        
-       /* We build up head, then assign it to p->route when we're done */
+       /* Build a tailq, then assign it to p->route when done.
+        * If backwards, we add entries from the head so they end up
+        * in reverse order. However, we do need to maintain a correct
+        * tail pointer because the contact is always at the end.
+        */
        head = NULL;
        tail = head;
        /* 1st we pass through all the hops in any Record-Route headers */
@@ -6631,12 +6635,7 @@ static void build_route(struct sip_pvt *p, struct sip_request *req, int backward
                rr = __get_header(req, "Record-Route", &start);
                if (*rr == '\0')
                        break;
-               for (;;) {
-                       /* Each route entry */
-                       /* Find < */
-                       rr = strchr(rr, '<');
-                       if (!rr) 
-                               break; /* No more hops */
+               for (; (rr = strchr(rr, '<')) ; rr += len) { /* Each route entry */
                        ++rr;
                        len = strcspn(rr, ">") + 1;
                        /* Make a struct route */
@@ -6650,7 +6649,8 @@ static void build_route(struct sip_pvt *p, struct sip_request *req, int backward
                                        thishop->next = head;
                                        head = thishop;
                                        /* If this was the first then it'll be the tail */
-                                       if (!tail) tail = thishop;
+                                       if (!tail)
+                                               tail = thishop;
                                } else {
                                        thishop->next = NULL;
                                        /* Link in at the end */
@@ -6661,7 +6661,6 @@ static void build_route(struct sip_pvt *p, struct sip_request *req, int backward
                                        tail = thishop;
                                }
                        }
-                       rr += len;
                }
        }