rxrpc: Fix DATA Tx to disable nofrag for UDP on AF_INET6 socket

commit 0e631eee17dcea576ab922fa70e4fdbd596ee452 upstream.

Fix the DATA packet transmission to disable nofrag for UDPv4 on an AF_INET6
socket as well as UDPv6 when trying to transmit fragmentably.

Without this, packets filled to the normal size used by the kernel AFS
client of 1412 bytes be rejected by udp_sendmsg() with EMSGSIZE
immediately.  The ->sk_error_report() notification hook is called, but
rxrpc doesn't generate a trace for it.

This is a temporary fix; a more permanent solution needs to involve
changing the size of the packets being filled in accordance with the MTU,
which isn't currently done in AF_RXRPC.  The reason for not doing so was
that, barring the last packet in an rx jumbo packet, jumbos can only be
assembled out of 1412-byte packets - and the plan was to construct jumbos
on the fly at transmission time.

Also, there's no point turning on IPV6_MTU_DISCOVER, since IPv6 has to
engage in this anyway since fragmentation is only done by the sender.  We
can then condense the switch-statement in rxrpc_send_data_packet().

Fixes: 75b54cb57ca3 ("rxrpc: Add IPv6 support")
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/rxrpc/local_object.c b/net/rxrpc/local_object.c
index 4c0087a48e8726919c04b8fa92d3d591905d1101..fe190a6918727891a0830ec6c812881d6ea428d4 100644 (file)
--- a/net/rxrpc/local_object.c
+++ b/net/rxrpc/local_object.c
@@ -169,15 +169,6 @@ static int rxrpc_open_socket(struct rxrpc_local *local, struct net *net)
                        goto error;
                }
 
-               /* we want to set the don't fragment bit */
-               opt = IPV6_PMTUDISC_DO;
-               ret = kernel_setsockopt(local->socket, SOL_IPV6, IPV6_MTU_DISCOVER,
-                                       (char *) &opt, sizeof(opt));
-               if (ret < 0) {
-                       _debug("setsockopt failed");
-                       goto error;
-               }
-
                /* Fall through and set IPv4 options too otherwise we don't get
                 * errors from IPv4 packets sent through the IPv6 socket.
                 */

diff --git a/net/rxrpc/output.c b/net/rxrpc/output.c
index b0aa08e3796de1909563f7448de224cded2a7f73..da8a555ec3f628117ad9f67b51186e7241b419fd 100644 (file)
--- a/net/rxrpc/output.c
+++ b/net/rxrpc/output.c
@@ -480,41 +480,21 @@ send_fragmentable:
        skb->tstamp = ktime_get_real();
 
        switch (conn->params.local->srx.transport.family) {
+       case AF_INET6:
        case AF_INET:
                opt = IP_PMTUDISC_DONT;
-               ret = kernel_setsockopt(conn->params.local->socket,
-                                       SOL_IP, IP_MTU_DISCOVER,
-                                       (char *)&opt, sizeof(opt));
-               if (ret == 0) {
-                       ret = kernel_sendmsg(conn->params.local->socket, &msg,
-                                            iov, 2, len);
-                       conn->params.peer->last_tx_at = ktime_get_seconds();
-
-                       opt = IP_PMTUDISC_DO;
-                       kernel_setsockopt(conn->params.local->socket, SOL_IP,
-                                         IP_MTU_DISCOVER,
-                                         (char *)&opt, sizeof(opt));
-               }
-               break;
-
-#ifdef CONFIG_AF_RXRPC_IPV6
-       case AF_INET6:
-               opt = IPV6_PMTUDISC_DONT;
-               ret = kernel_setsockopt(conn->params.local->socket,
-                                       SOL_IPV6, IPV6_MTU_DISCOVER,
-                                       (char *)&opt, sizeof(opt));
-               if (ret == 0) {
-                       ret = kernel_sendmsg(conn->params.local->socket, &msg,
-                                            iov, 2, len);
-                       conn->params.peer->last_tx_at = ktime_get_seconds();
-
-                       opt = IPV6_PMTUDISC_DO;
-                       kernel_setsockopt(conn->params.local->socket,
-                                         SOL_IPV6, IPV6_MTU_DISCOVER,
-                                         (char *)&opt, sizeof(opt));
-               }
+               kernel_setsockopt(conn->params.local->socket,
+                                 SOL_IP, IP_MTU_DISCOVER,
+                                 (char *)&opt, sizeof(opt));
+               ret = kernel_sendmsg(conn->params.local->socket, &msg,
+                                    iov, 2, len);
+               conn->params.peer->last_tx_at = ktime_get_seconds();
+
+               opt = IP_PMTUDISC_DO;
+               kernel_setsockopt(conn->params.local->socket,
+                                 SOL_IP, IP_MTU_DISCOVER,
+                                 (char *)&opt, sizeof(opt));
                break;
-#endif
 
        default:
                BUG();