shinys000114/linux
1
0
Fork 0
mirror of https://github.com/hardkernel/linux.git synced 2026-06-10 12:57:06 +09:00
Code Issues Packages Projects Releases Wiki Activity

net: small bug on rxhash calculation

Browse Source 
[ Upstream commit 6862234238 ]

In the current rxhash calculation function, while the
sorting of the ports/addrs is coherent (you get the
same rxhash for packets sharing the same 4-tuple, in
both directions), ports and addrs are sorted
independently. This implies packets from a connection
between the same addresses but crossed ports hash to
the same rxhash.

For example, traffic between A=S:l and B=L:s is hashed
(in both directions) from {L, S, {s, l}}. The same
rxhash is obtained for packets between C=S:s and D=L:l.

This patch ensures that you either swap both addrs and ports,
or you swap none. Traffic between A and B, and traffic
between C and D, get their rxhash from different sources
({L, S, {l, s}} for A<->B, and {L, S, {s, l}} for C<->D)

The patch is co-written with Eric Dumazet <edumazet@google.com>

Signed-off-by: Chema Gonzalez <chema@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Chema Gonzalez
2012-09-07 13:40:50 +00:00
committed by Greg Kroah-Hartman
parent 0ddaf88b27
commit 74665a9b4f
1 changed files with 6 additions and 5 deletions
Download Patch File Download Diff File Expand all files Collapse all files

11
net/core/dev.c
View File

@@ -2559,16 +2559,17 @@ __u32 __skb_get_rxhash(struct sk_buff *skb)
poff = proto_ports_offset(ip_proto);
if (poff >= 0) {
nhoff += ihl * 4 + poff;
if (pskb_may_pull(skb, nhoff + 4)) {
if (pskb_may_pull(skb, nhoff + 4))
ports.v32 = * (__force u32 *) (skb->data + nhoff);
if (ports.v16[1] < ports.v16[0])
swap(ports.v16[0], ports.v16[1]);
}
}
/* get a consistent hash (same value on both flow directions) */
if (addr2 < addr1)
if (addr2 < addr1 ||
(addr2 == addr1 &&
ports.v16[1] < ports.v16[0])) {
swap(addr1, addr2);
swap(ports.v16[0], ports.v16[1]);
}
hash = jhash_3words(addr1, addr2, ports.v32, hashrnd);
if (!hash)