tcp: Use a different log message and level if there's more addresses to try

This lowers the level of warnings printed if trying to connect
to a host name that provides both v6 and v4 addresses but the
service only is available on the v4 address (often occurring for
'localhost', with servers that aren't v6-aware).
Signed-off-by: Martin Storsjö <martin@martin.st>

libavformat/network.c

@@ -240,7 +240,8 @@ int ff_listen_bind(int fd, const struct sockaddr *addr,
 }
 
 int ff_listen_connect(int fd, const struct sockaddr *addr,
-                      socklen_t addrlen, int timeout, URLContext *h)
+                      socklen_t addrlen, int timeout, URLContext *h,
+                      int will_try_next)
 {
     struct pollfd p = {fd, POLLOUT, 0};
     int ret;
@@ -267,9 +268,13 @@ int ff_listen_connect(int fd, const struct sockaddr *addr,
                 char errbuf[100];
                 ret = AVERROR(ret);
                 av_strerror(ret, errbuf, sizeof(errbuf));
-                av_log(h, AV_LOG_ERROR,
-                       "Connection to %s failed: %s\n",
-                       h->filename, errbuf);
+                if (will_try_next)
+                    av_log(h, AV_LOG_WARNING,
+                           "Connection to %s failed (%s), trying next address\n",
+                           h->filename, errbuf);
+                else
+                    av_log(h, AV_LOG_ERROR, "Connection to %s failed: %s\n",
+                           h->filename, errbuf);
             }
         default:
             return ret;

libavformat/network.h

@@ -238,11 +238,14 @@ int ff_listen_bind(int fd, const struct sockaddr *addr,
  * @param timeout  Polling timeout in milliseconds.
  * @param h        URLContext providing interrupt check
  *                 callback and logging context.
+ * @param will_try_next Whether the caller will try to connect to another
+ *                 address for the same host name, affecting the form of
+ *                 logged errors.
  * @return         0 on success, AVERROR on failure.
  */
 int ff_listen_connect(int fd, const struct sockaddr *addr,
                       socklen_t addrlen, int timeout,
-                      URLContext *h);
+                      URLContext *h, int will_try_next);
 
 int ff_http_match_no_proxy(const char *no_proxy, const char *hostname);
 

libavformat/tcp.c

@@ -100,7 +100,7 @@ static int tcp_open(URLContext *h, const char *uri, int flags)
         }
     } else {
         if ((ret = ff_listen_connect(fd, cur_ai->ai_addr, cur_ai->ai_addrlen,
-                                     timeout * 100, h)) < 0) {
+                                     timeout * 100, h, cur_ai->ai_next)) < 0) {
 
             if (ret == AVERROR_EXIT)
                 goto fail1;

libavformat/unix.c

@@ -83,7 +83,7 @@ static int unix_open(URLContext *h, const char *filename, int flags)
         }
     } else {
         ret = ff_listen_connect(fd, (struct sockaddr *)&s->addr,
-                                sizeof(s->addr), s->timeout, h);
+                                sizeof(s->addr), s->timeout, h, 0);
         if (ret < 0)
             goto fail;
     }