[INET]: local port range robustness

[net-next-2.6.git] / net / ipv4 / inet_connection_sock.c

diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
index fbe7714f21d08593beecb3945f2f85848b506be8..3cef12835c4b2bfa86b50a74a788488cd5ac9ea1 100644 (file)
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
@@ -33,6 +33,19 @@ EXPORT_SYMBOL(inet_csk_timer_bug_msg);
  * This array holds the first and last local port number.
  */
 int sysctl_local_port_range[2] = { 32768, 61000 };
+DEFINE_SEQLOCK(sysctl_port_range_lock);
+
+void inet_get_local_port_range(int *low, int *high)
+{
+       unsigned seq;
+       do {
+               seq = read_seqbegin(&sysctl_port_range_lock);
+
+               *low = sysctl_local_port_range[0];
+               *high = sysctl_local_port_range[1];
+       } while (read_seqretry(&sysctl_port_range_lock, seq));
+}
+EXPORT_SYMBOL(inet_get_local_port_range);
 
 int inet_csk_bind_conflict(const struct sock *sk,
                           const struct inet_bind_bucket *tb)
@@ -77,10 +90,11 @@ int inet_csk_get_port(struct inet_hashinfo *hashinfo,
 
        local_bh_disable();
        if (!snum) {
-               int low = sysctl_local_port_range[0];
-               int high = sysctl_local_port_range[1];
-               int remaining = (high - low) + 1;
-               int rover = net_random() % (high - low) + low;
+               int remaining, rover, low, high;
+
+               inet_get_local_port_range(&low, &high);
+               remaining = high - low;
+               rover = net_random() % remaining + low;
 
                do {
                        head = &hashinfo->bhash[inet_bhashfn(rover, hashinfo->bhash_size)];