From fcdd1cf4dd63aecf86c987d7f4ec7187be5c2fbc Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Mon, 22 Sep 2014 13:19:44 -0700 Subject: tcp: avoid possible arithmetic overflows icsk_rto is a 32bit field, and icsk_backoff can reach 15 by default, or more if some sysctl (eg tcp_retries2) are changed. Better use 64bit to perform icsk_rto << icsk_backoff operations As Joe Perches suggested, add a helper for this. Yuchung spotted the tcp_v4_err() case. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- include/net/inet_connection_sock.h | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'include/net/inet_connection_sock.h') diff --git a/include/net/inet_connection_sock.h b/include/net/inet_connection_sock.h index 5fbe6568c3cf..848e85cb5c61 100644 --- a/include/net/inet_connection_sock.h +++ b/include/net/inet_connection_sock.h @@ -242,6 +242,15 @@ static inline void inet_csk_reset_xmit_timer(struct sock *sk, const int what, #endif } +static inline unsigned long +inet_csk_rto_backoff(const struct inet_connection_sock *icsk, + unsigned long max_when) +{ + u64 when = (u64)icsk->icsk_rto << icsk->icsk_backoff; + + return (unsigned long)min_t(u64, when, max_when); +} + struct sock *inet_csk_accept(struct sock *sk, int flags, int *err); struct request_sock *inet_csk_search_req(const struct sock *sk, -- cgit v1.2.3-59-g8ed1b