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authorStephen Hemminger <shemminger@linux-foundation.org>2007-10-10 17:30:18 -0700
committerDavid S. Miller <davem@davemloft.net>2007-10-10 17:30:18 -0700
commit06393009000779b00a558fd2f280882cc7dc2008 (patch)
tree0cd2e1f4cedd58c3c8056018bb6148dddd21d6ab /net/sctp/socket.c
parent3c0cfc135829b98f7a4894938652f9ef78e24237 (diff)
[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 <shemminger@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sctp/socket.c')
-rw-r--r--net/sctp/socket.c21
1 files changed, 5 insertions, 16 deletions
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index f3e1a9c811a..7cd58ef84ed 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;