From 06393009000779b00a558fd2f280882cc7dc2008 Mon Sep 17 00:00:00 2001 From: Stephen Hemminger Date: Wed, 10 Oct 2007 17:30:18 -0700 Subject: [SCTP]: port randomization Add port randomization rather than a simple fixed rover for use with SCTP. This makes it act similar to TCP, UDP, DCCP when allocating ports. No longer need port_alloc_lock as well (suggestion by Brian Haley). Signed-off-by: Stephen Hemminger Signed-off-by: David S. Miller --- net/sctp/socket.c | 21 +++++---------------- 1 file changed, 5 insertions(+), 16 deletions(-) (limited to 'net/sctp/socket.c') diff --git a/net/sctp/socket.c b/net/sctp/socket.c index f3e1a9c811ad..7cd58ef84eda 100644 --- a/net/sctp/socket.c +++ b/net/sctp/socket.c @@ -5314,22 +5314,13 @@ static long sctp_get_port_local(struct sock *sk, union sctp_addr *addr) sctp_local_bh_disable(); if (snum == 0) { - /* Search for an available port. - * - * 'sctp_port_rover' was the last port assigned, so - * we start to search from 'sctp_port_rover + - * 1'. What we do is first check if port 'rover' is - * already in the hash table; if not, we use that; if - * it is, we try next. - */ - int low = sysctl_local_port_range[0]; - int high = sysctl_local_port_range[1]; - int remaining = (high - low) + 1; - int rover; + /* Search for an available port. */ + unsigned int low = sysctl_local_port_range[0]; + unsigned int high = sysctl_local_port_range[1]; + unsigned int remaining = (high - low) + 1; + unsigned int rover = net_random() % remaining + low; int index; - sctp_spin_lock(&sctp_port_alloc_lock); - rover = sctp_port_rover; do { rover++; if ((rover < low) || (rover > high)) @@ -5344,8 +5335,6 @@ static long sctp_get_port_local(struct sock *sk, union sctp_addr *addr) next: sctp_spin_unlock(&head->lock); } while (--remaining > 0); - sctp_port_rover = rover; - sctp_spin_unlock(&sctp_port_alloc_lock); /* Exhausted local port range during search? */ ret = 1; -- cgit v1.2.2