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authorDavid Howells <dhowells@redhat.com>2007-05-04 12:41:11 -0700
committerDavid S. Miller <davem@davemloft.net>2007-05-04 12:41:11 -0700
commit224711df5c00f7540b89f32a8225866031977f17 (patch)
tree7b515b1e0fff3b5c8ffc01400486beb300395f9e /net/rxrpc/ar-peer.c
parentda99f0565477899f08b76ffcb32afbf6fa95d64a (diff)
downloadop-kernel-dev-224711df5c00f7540b89f32a8225866031977f17.zip
op-kernel-dev-224711df5c00f7540b89f32a8225866031977f17.tar.gz
[AF_RXRPC]: Sort out MTU handling.
Sort out the MTU determination and handling in AF_RXRPC: (1) If it's present, parse the additional information supplied by the peer at the end of the ACK packet (struct ackinfo) to determine the MTU sizes that peer is willing to support. (2) Initialise the MTU size to that peer from the kernel's routing records. (3) Send ACKs rather than ACKALLs as the former carry the additional info, and the latter do not. (4) Declare the interface MTU size in outgoing ACKs as a maximum amount of data that can be stuffed into an RxRPC packet without it having to be fragmented to come in this computer's NIC. (5) If sendmsg() is given MSG_MORE then it should allocate an skb of the maximum size rather than one just big enough for the data it's got left to process on the theory that there is more data to come that it can append to that packet. This means, for example, that if AFS does a large StoreData op, all the packets barring the last will be filled to the maximum unfragmented size. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/rxrpc/ar-peer.c')
-rw-r--r--net/rxrpc/ar-peer.c45
1 files changed, 44 insertions, 1 deletions
diff --git a/net/rxrpc/ar-peer.c b/net/rxrpc/ar-peer.c
index d399de4..ce08b78 100644
--- a/net/rxrpc/ar-peer.c
+++ b/net/rxrpc/ar-peer.c
@@ -19,6 +19,7 @@
#include <net/sock.h>
#include <net/af_rxrpc.h>
#include <net/ip.h>
+#include <net/route.h>
#include "ar-internal.h"
static LIST_HEAD(rxrpc_peers);
@@ -28,6 +29,47 @@ static DECLARE_WAIT_QUEUE_HEAD(rxrpc_peer_wq);
static void rxrpc_destroy_peer(struct work_struct *work);
/*
+ * assess the MTU size for the network interface through which this peer is
+ * reached
+ */
+static void rxrpc_assess_MTU_size(struct rxrpc_peer *peer)
+{
+ struct rtable *rt;
+ struct flowi fl;
+ int ret;
+
+ peer->if_mtu = 1500;
+
+ memset(&fl, 0, sizeof(fl));
+
+ switch (peer->srx.transport.family) {
+ case AF_INET:
+ fl.oif = 0;
+ fl.proto = IPPROTO_UDP,
+ fl.nl_u.ip4_u.saddr = 0;
+ fl.nl_u.ip4_u.daddr = peer->srx.transport.sin.sin_addr.s_addr;
+ fl.nl_u.ip4_u.tos = 0;
+ /* assume AFS.CM talking to AFS.FS */
+ fl.uli_u.ports.sport = htons(7001);
+ fl.uli_u.ports.dport = htons(7000);
+ break;
+ default:
+ BUG();
+ }
+
+ ret = ip_route_output_key(&rt, &fl);
+ if (ret < 0) {
+ kleave(" [route err %d]", ret);
+ return;
+ }
+
+ peer->if_mtu = dst_mtu(&rt->u.dst);
+ dst_release(&rt->u.dst);
+
+ kleave(" [if_mtu %u]", peer->if_mtu);
+}
+
+/*
* allocate a new peer
*/
static struct rxrpc_peer *rxrpc_alloc_peer(struct sockaddr_rxrpc *srx,
@@ -47,7 +89,8 @@ static struct rxrpc_peer *rxrpc_alloc_peer(struct sockaddr_rxrpc *srx,
peer->debug_id = atomic_inc_return(&rxrpc_debug_id);
memcpy(&peer->srx, srx, sizeof(*srx));
- peer->mtu = peer->if_mtu = 65535;
+ rxrpc_assess_MTU_size(peer);
+ peer->mtu = peer->if_mtu;
if (srx->transport.family == AF_INET) {
peer->hdrsize = sizeof(struct iphdr);
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