Feature: Allow listen sockets to virtually handle other sockets traffic.

This adds on-behalf-of="#id" to <listen-socket>. It allows a socket
to handle the traffic that was originally meant of another (virtual)
listen socket.

src/cfgfile.c

@@ -186,6 +186,19 @@ static listener_type_t config_str_to_listener_type(const char *str)
     }
 }
 
+char * config_href_to_id(const char *href)
+{
+    if (!href || !*href)
+        return NULL;
+
+    if (*href != '#') {
+        ICECAST_LOG_ERROR("Can not convert string \"%H\" to ID.", href);
+        return NULL;
+    }
+
+    return strdup(href+1);
+}
+
 static void create_locks(void)
 {
     thread_mutex_create(&_locks.relay_lock);
@@ -595,6 +608,7 @@ listener_t *config_clear_listener(listener_t *listener)
     {
         next = listener->next;
         if (listener->id)               xmlFree(listener->id);
+        if (listener->on_behalf_of)     free(listener->on_behalf_of);
         if (listener->bind_address)     xmlFree(listener->bind_address);
         if (listener->shoutcast_mount)  xmlFree(listener->shoutcast_mount);
         free (listener);
@@ -1761,6 +1775,12 @@ static void _parse_listen_socket(xmlDocPtr      doc,
 
     listener->id  = (char *)xmlGetProp(node, XMLSTR("id"));
 
+    tmp = (char*)xmlGetProp(node, XMLSTR("on-behalf-of"));
+    if (tmp) {
+        listener->on_behalf_of = config_href_to_id(tmp);
+        xmlFree(tmp);
+    }
+
     tmp  = (char *)xmlGetProp(node, XMLSTR("type"));
     listener->type = config_str_to_listener_type(tmp);
     xmlFree(tmp);
@@ -2511,6 +2531,9 @@ listener_t *config_copy_listener_one(const listener_t *listener) {
     n->so_sndbuf = listener->so_sndbuf;
     n->type = listener->type;
     n->id = (char*)xmlStrdup(XMLSTR(listener->id));
+    if (listener->on_behalf_of) {
+        n->on_behalf_of = strdup(listener->on_behalf_of);
+    }
     n->bind_address = (char*)xmlStrdup(XMLSTR(listener->bind_address));
     n->shoutcast_compat = listener->shoutcast_compat;
     n->shoutcast_mount = (char*)xmlStrdup(XMLSTR(listener->shoutcast_mount));

src/cfgfile.h

@@ -156,6 +156,7 @@ typedef enum _listener_type_tag {
 typedef struct _listener_t {
     struct _listener_t *next;
     char *id;
+    char *on_behalf_of;
     listener_type_t type;
     int port;
     int so_sndbuf;

src/listensocket.c

@@ -53,6 +53,7 @@ struct listensocket_tag {
     sock_t sock;
 };
 
+static listensocket_t * listensocket_container_get_by_id(listensocket_container_t *self, const char *id);
 static int listensocket_container_configure__unlocked(listensocket_container_t *self, const ice_config_t *config);
 static int listensocket_container_setup__unlocked(listensocket_container_t *self);
 static ssize_t listensocket_container_sockcount__unlocked(listensocket_container_t *self);
@@ -466,6 +467,29 @@ static ssize_t listensocket_container_sockcount__unlocked(listensocket_container
     return count;
 }
 
+static listensocket_t * listensocket_container_get_by_id(listensocket_container_t *self, const char *id)
+{
+    size_t i;
+    const listener_t *listener;
+
+    for (i = 0; i < self->sock_len; i++) {
+        if (self->sock[i] != NULL) {
+            listener = listensocket_get_listener(self->sock[i]);
+            if (listener) {
+                if (strcmp(listener->id, id) == 0) {
+                    listensocket_release_listener(self->sock[i]);
+                    if (refobject_ref(self->sock[i]) == 0) {
+                        return self->sock[i];
+                    }
+                }
+                listensocket_release_listener(self->sock[i]);
+            }
+        }
+    }
+
+    return NULL;
+}
+
 /* ---------------------------------------------------------------------------- */
 
 static void __listensocket_free(refobject_t self, void **userdata)
@@ -679,6 +703,16 @@ connection_t *              listensocket_accept(listensocket_t *self, listensock
         memmove(ip, ip+7, strlen(ip+7)+1);
     }
 
+    ICECAST_LOG_DEBUG("Client on socket \"%H\".", self->listener->id);
+
+    if (self->listener->on_behalf_of) {
+        ICECAST_LOG_DEBUG("This socket is acting on behalf of \"%H\"", self->listener->on_behalf_of);
+        effective = listensocket_container_get_by_id(container, self->listener->on_behalf_of);
+        if (!effective) {
+            ICECAST_LOG_ERROR("Can not find listen socket with ID \"%H\". Will continue on behalf of myself.", self->listener->on_behalf_of);
+        }
+    }
+
     if (!effective) {
         effective = self;
         refobject_ref(effective);