linux.git/net/ipv4/ip_output.c, branch v2.6.31

ipv4: make ip_append_data() handle NULL routing table

2009-08-27T19:23:43+00:00

Add a check in ip_append_data() for NULL *rtp to prevent future bugs in
callers from being exploitable.

Signed-off-by: Julien Tinnes 
Signed-off-by: Tavis Ormandy 
Acked-by: David S. Miller 
Signed-off-by: Linus Torvalds

net: ip_push_pending_frames() fix

2009-07-12T03:26:21+00:00

After commit 2b85a34e911bf483c27cfdd124aeb1605145dc80
(net: No more expensive sock_hold()/sock_put() on each tx)
we do not take any more references on sk->sk_refcnt on outgoing packets.

I forgot to delete two __sock_put() from ip_push_pending_frames()
and ip6_push_pending_frames().

Reported-by: Emil S Tantilov 
Signed-off-by: Eric Dumazet 
Tested-by: Emil S Tantilov 
Signed-off-by: David S. Miller

net: No more expensive sock_hold()/sock_put() on each tx

2009-06-11T09:55:43+00:00

One of the problem with sock memory accounting is it uses
a pair of sock_hold()/sock_put() for each transmitted packet.

This slows down bidirectional flows because the receive path
also needs to take a refcount on socket and might use a different
cpu than transmit path or transmit completion path. So these
two atomic operations also trigger cache line bounces.

We can see this in tx or tx/rx workloads (media gateways for example),
where sock_wfree() can be in top five functions in profiles.

We use this sock_hold()/sock_put() so that sock freeing
is delayed until all tx packets are completed.

As we also update sk_wmem_alloc, we could offset sk_wmem_alloc
by one unit at init time, until sk_free() is called.
Once sk_free() is called, we atomic_dec_and_test(sk_wmem_alloc)
to decrement initial offset and atomicaly check if any packets
are in flight.

skb_set_owner_w() doesnt call sock_hold() anymore

sock_wfree() doesnt call sock_put() anymore, but check if sk_wmem_alloc
reached 0 to perform the final freeing.

Drawback is that a skb->truesize error could lead to unfreeable sockets, or
even worse, prematurely calling __sk_free() on a live socket.

Nice speedups on SMP. tbench for example, going from 2691 MB/s to 2711 MB/s
on my 8 cpu dev machine, even if tbench was not really hitting sk_refcnt
contention point. 5 % speedup on a UDP transmit workload (depends
on number of flows), lowering TX completion cpu usage.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

ipv4: Use frag list abstraction interfaces.

2009-06-09T07:19:37+00:00

Signed-off-by: David S. Miller

net: skb->dst accessors

2009-06-03T09:51:04+00:00

Define three accessors to get/set dst attached to a skb

struct dst_entry *skb_dst(const struct sk_buff *skb)

void skb_dst_set(struct sk_buff *skb, struct dst_entry *dst)

void skb_dst_drop(struct sk_buff *skb)
This one should replace occurrences of :
dst_release(skb->dst)
skb->dst = NULL;

Delete skb->dst field

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

net: skb->rtable accessor

2009-06-03T09:51:02+00:00

Define skb_rtable(const struct sk_buff *skb) accessor to get rtable from skb

Delete skb->rtable field

Setting rtable is not allowed, just set dst instead as rtable is an alias.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

snmp: add missing counters for RFC 4293

2009-04-27T09:45:02+00:00

The IP MIB (RFC 4293) defines stats for InOctets, OutOctets, InMcastOctets and
OutMcastOctets:
http://tools.ietf.org/html/rfc4293
But it seems we don't track those in any way that easy to separate from other
protocols.  This patch adds those missing counters to the stats file. Tested
successfully by me

With help from Eric Dumazet.

Signed-off-by: Neil Horman 
Signed-off-by: David S. Miller

ip: support for TX timestamps on UDP and RAW sockets

2009-02-16T06:43:38+00:00

Instructions for time stamping outgoing packets are take from the
socket layer and later copied into the new skb.

Signed-off-by: Patrick Ohly 
Signed-off-by: David S. Miller

net: avoid a pair of dst_hold()/dst_release() in ip_push_pending_frames()

2008-11-25T00:07:50+00:00

We can reduce pressure on dst entry refcount that slowdown UDP transmit
path on SMP machines. This pressure is visible on RTP servers when
delivering content to mediagateways, especially big ones, handling
thousand of streams. Several cpus send UDP frames to the same
destination, hence use the same dst entry.

This patch makes ip_push_pending_frames() steal the refcount its
callers had to take when filling inet->cork.dst.

This doesnt avoid all refcounting, but still gives speedups on SMP,
on UDP/RAW transmit path.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

net: avoid a pair of dst_hold()/dst_release() in ip_append_data()

2008-11-24T23:52:46+00:00

We can reduce pressure on dst entry refcount that slowdown UDP transmit
path on SMP machines. This pressure is visible on RTP servers when
delivering content to mediagateways, especially big ones, handling
thousand of streams. Several cpus send UDP frames to the same
destination, hence use the same dst entry.

This patch makes ip_append_data() eventually steal the refcount its
callers had to take on the dst entry.

This doesnt avoid all refcounting, but still gives speedups on SMP,
on UDP/RAW transmit path

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller