Events: Socket creation after getaddrinfo and IPv4 and IPv6 packet capture

Issue: Currently, the socket creation is done
prior to getaddrinfo function being invoked. This
can cause mismatch in the protocol and address
families of the created socket and the result
of the getaddrinfo api. Also, the glustereventsd
UDP server by default only captures IPv4 packets
hence IPv6 packets are not even captured.

Code Changes:
1. Modified the socket creation in such a way that
the parameters taken in are dependent upon the
result of the getaddrinfo function.
2. Created a subclass for adding address family
in glustereventsd.py for both AF_INET and AF_INET6.
3. Modified addresses in the eventsapiconf.py.in

Reasoning behind the approach:
1. If we are using getaddrinfo function then
socket creation should happen only after we
check if we received back valid addresses.
Hence socket creation should come after the call
to getaddrinfo
2. The listening server which pushes the events
to the webhook has to listen for both IPv4
and IPv6 messages as we would not be sure as to
what address family is picked in _gf_event.

Fixes: #1377
Change-Id: I568dcd1a977c8832f0fef981e1f81cac7043c760
Signed-off-by: srijan-sivakumar <ssivakum@redhat.com>

1 files changed, 17 insertions, 8 deletions

diff --git a/libglusterfs/src/events.c b/libglusterfs/src/events.c
index 908a318a8a1..6369e8f55be 100644
--- a/libglusterfs/src/events.c
+++ b/libglusterfs/src/events.c
@@ -51,13 +51,6 @@ _gf_event(eventtypes_t event, const char *fmt, ...)
         goto out;
     }
 
-    /* Initialize UDP socket */
-    sock = socket(AF_INET, SOCK_DGRAM, 0);
-    if (sock < 0) {
-        ret = EVENT_ERROR_SOCKET;
-        goto out;
-    }
-
     if (ctx) {
         volfile_server_transport = ctx->cmd_args.volfile_server_transport;
     }
@@ -66,7 +59,6 @@ _gf_event(eventtypes_t event, const char *fmt, ...)
     }
 
     /* host = NULL returns localhost */
-    host = NULL;
     if (ctx && ctx->cmd_args.volfile_server &&
         (strcmp(volfile_server_transport, "unix"))) {
         /* If it is client code then volfile_server is set
@@ -84,6 +76,23 @@ _gf_event(eventtypes_t event, const char *fmt, ...)
         goto out;
     }
 
+    // iterate over the result and break when socket creation is success.
+    for (; result != NULL; result = result->ai_next) {
+        sock = socket(result->ai_family, result->ai_socktype,
+                      result->ai_protocol);
+        if (sock != -1) {
+            break;
+        }
+    }
+    /*
+     * If none of the addrinfo structures lead to a successful socket
+     * creation, socket creation has failed.
+     */
+    if (sock < 0) {
+        ret = EVENT_ERROR_SOCKET;
+        goto out;
+    }
+
     va_start(arguments, fmt);
     ret = gf_vasprintf(&msg, fmt, arguments);
     va_end(arguments);