af-packet: fix init sync with no traffic

Previously the sync code would depend on traffic to complete. This
patch adds poll support and can complete the setup if the poll timeout
is reached as well.

Part of bug #1130.

src/source-af-packet.c

@@ -1016,31 +1016,59 @@ static int AFPReadAndDiscardFromRing(AFPThreadVars *ptv, struct timeval *synctv)
     return 0;
 }
 
+/** \brief wait for all afpacket threads to fully init
+ *
+ *  Discard packets before all threads are ready, as the cluster
+ *  setup is not complete yet.
+ *
+ *  if AFPPeersListStarted() returns true init is complete
+ *
+ *  \retval r 1 = happy, otherwise unhappy
+ */
 static int AFPSynchronizeStart(AFPThreadVars *ptv)
 {
     int r;
     struct timeval synctv;
+    struct pollfd fds;
+
+    fds.fd = ptv->socket;
+    fds.events = POLLIN;
 
     /* Set timeval to end of the world */
     synctv.tv_sec = 0xffffffff;
     synctv.tv_usec = 0xffffffff;
 
     while (1) {
-        if (AFPPeersListStarted() && synctv.tv_sec == (time_t) 0xffffffff) {
-            gettimeofday(&synctv, NULL);
-        }
-        if (ptv->flags & AFP_RING_MODE) {
-            r = AFPReadAndDiscardFromRing(ptv, &synctv);
+        r = poll(&fds, 1, POLL_TIMEOUT);
+        if (r > 0 &&
+                (fds.revents & (POLLHUP|POLLRDHUP|POLLERR|POLLNVAL))) {
+            SCLogWarning(SC_ERR_AFP_READ, "poll failed %02x",
+                    fds.revents & (POLLHUP|POLLRDHUP|POLLERR|POLLNVAL));
+            return 0;
+        } else if (r > 0) {
+            if (AFPPeersListStarted() && synctv.tv_sec == (time_t) 0xffffffff) {
+                gettimeofday(&synctv, NULL);
+            }
+            if (ptv->flags & AFP_RING_MODE) {
+                r = AFPReadAndDiscardFromRing(ptv, &synctv);
+            } else {
+                r = AFPReadAndDiscard(ptv, &synctv);
+            }
+            SCLogDebug("Discarding on %s", ptv->tv->name);
+            switch (r) {
+                case 1:
+                    SCLogInfo("Starting to read on %s", ptv->tv->name);
+                    return 1;
+                case -1:
+                    return r;
+            }
+        /* no packets */
+        } else if (r == 0 && AFPPeersListStarted()) {
+            SCLogInfo("Starting to read on %s", ptv->tv->name);
+            return 1;
         } else {
-            r = AFPReadAndDiscard(ptv, &synctv);
-        }
-        SCLogDebug("Discarding on %s", ptv->tv->name);
-        switch (r) {
-            case 1:
-                SCLogInfo("Starting to read on %s", ptv->tv->name);
-                return 1;
-            case -1:
-                return r;
+            SCLogWarning(SC_ERR_AFP_READ, "poll failed with retval %d", r);
+            return 0;
         }
     }
     return 1;