Commit 1f74e613 authored by Christoph Paasch's avatar Christoph Paasch Committed by David S. Miller

tcp: Fix integer-overflow in TCP vegas

In vegas we do a multiplication of the cwnd and the rtt. This
may overflow and thus their result is stored in a u64. However, we first
need to cast the cwnd so that actually 64-bit arithmetic is done.

Then, we need to do do_div to allow this to be used on 32-bit arches.

Cc: Stephen Hemminger <stephen@networkplumber.org>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: David Laight <David.Laight@ACULAB.COM>
Cc: Doug Leith <doug.leith@nuim.ie>
Fixes: 8d3a564d (tcp: tcp_vegas cong avoid fix)
Signed-off-by: default avatarChristoph Paasch <christoph.paasch@uclouvain.be>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 45a07695
...@@ -218,7 +218,8 @@ static void tcp_vegas_cong_avoid(struct sock *sk, u32 ack, u32 acked) ...@@ -218,7 +218,8 @@ static void tcp_vegas_cong_avoid(struct sock *sk, u32 ack, u32 acked)
* This is: * This is:
* (actual rate in segments) * baseRTT * (actual rate in segments) * baseRTT
*/ */
target_cwnd = tp->snd_cwnd * vegas->baseRTT / rtt; target_cwnd = (u64)tp->snd_cwnd * vegas->baseRTT;
do_div(target_cwnd, rtt);
/* Calculate the difference between the window we had, /* Calculate the difference between the window we had,
* and the window we would like to have. This quantity * and the window we would like to have. This quantity
......
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