Fix --mtu-disc option with IPv6 transport

Socket configuration of MTU discovery was done unconditionally at IP level,
which has no effect for other protocols. This fixes the issue of OpenVPN
sending fragmented tcp6/udp6 packets even when 'mtu-disc yes' option is
passed.

Patch V2 (by Arne Schwabe): Rebase to current master and have
separate #ifdefs for IPv4 an IPv6

Signed-off-by: Julien Muchembled <jm@nexedi.com>
Acked-by: Arne Schwabe <arne@rfc2549.org>
Acked-by: Gert Doering <gert@greenie.muc.de>
Message-Id: <1444470291-2980-1-git-send-email-arne@rfc2549.org>
URL: http://article.gmane.org/gmane.network.openvpn.devel/10229
Signed-off-by: Gert Doering <gert@greenie.muc.de>

diff --git a/src/openvpn/mtu.c b/src/openvpn/mtu.c
index 3665a34ddd05bbb7ce66620fc3dca49078837145..24531c92a8b93cdb21f7eac87923482d4057c6e7 100644 (file)
--- a/src/openvpn/mtu.c
+++ b/src/openvpn/mtu.c
@@ -153,17 +153,32 @@ frame_print (const struct frame *frame,
 #define MTUDISC_NOT_SUPPORTED_MSG "--mtu-disc is not supported on this OS"
 
 void
-set_mtu_discover_type (int sd, int mtu_type)
+set_mtu_discover_type (int sd, int mtu_type, sa_family_t proto_af)
 {
   if (mtu_type >= 0)
     {
-#if defined(HAVE_SETSOCKOPT) && defined(SOL_IP) && defined(IP_MTU_DISCOVER)
-      if (setsockopt (sd, SOL_IP, IP_MTU_DISCOVER, (void *) &mtu_type, sizeof (mtu_type)))
-       msg (M_ERR, "Error setting IP_MTU_DISCOVER type=%d on TCP/UDP socket",
-            mtu_type);
-#else
-      msg (M_FATAL, MTUDISC_NOT_SUPPORTED_MSG);
+      switch (proto_af)
+       {
+#if defined(HAVE_SETSOCKOPT) && defined(IP_MTU_DISCOVER)
+       case AF_INET:
+         if (setsockopt
+             (sd, IPPROTO_IP, IP_MTU_DISCOVER, &mtu_type, sizeof (mtu_type)))
+           msg (M_ERR, "Error setting IP_MTU_DISCOVER type=%d on TCP/UDP socket",
+                mtu_type);
+         break;
+#endif
+#if defined(HAVE_SETSOCKOPT) && defined(IPV6_MTU_DISCOVER)
+       case AF_INET6:
+         if (setsockopt
+             (sd, IPPROTO_IPV6, IPV6_MTU_DISCOVER, &mtu_type, sizeof (mtu_type)))
+           msg (M_ERR, "Error setting IPV6_MTU_DISCOVER type=%d on TCP6/UDP6 socket",
+                mtu_type);
+         break;
 #endif
+       default:
+         msg (M_FATAL, MTUDISC_NOT_SUPPORTED_MSG);
+         break;
+       }
     }
 }
 

diff --git a/src/openvpn/mtu.h b/src/openvpn/mtu.h
index bccd6810fdec5dea3e54d50df80045afaf77dc72..f94de89b73c3f902c30941f5cdb3615ab8a787c8 100644 (file)
--- a/src/openvpn/mtu.h
+++ b/src/openvpn/mtu.h
@@ -207,7 +207,7 @@ void frame_print (const struct frame *frame,
                  int level,
                  const char *prefix);
 
-void set_mtu_discover_type (int sd, int mtu_type);
+void set_mtu_discover_type (int sd, int mtu_type, sa_family_t proto_af);
 int translate_mtu_discover_type_name (const char *name);
 
 /*

diff --git a/src/openvpn/socket.c b/src/openvpn/socket.c
index bd8dcb1bcdb3cb9ec006b5f4b128e1aa89d1a330..925665c521326456f2d20b7c058189d30e5ab28e 100644 (file)
--- a/src/openvpn/socket.c
+++ b/src/openvpn/socket.c
@@ -1676,7 +1676,7 @@ phase2_set_socket_flags (struct link_socket* sock)
     set_cloexec (sock->ctrl_sd);
 
   /* set Path MTU discovery options on the socket */
-  set_mtu_discover_type (sock->sd, sock->mtu_discover_type);
+  set_mtu_discover_type (sock->sd, sock->mtu_discover_type, sock->info.af);
 
 #if EXTENDED_SOCKET_ERROR_CAPABILITY
   /* if the OS supports it, enable extended error passing on the socket */