tcp: improve REUSEADDR/NOREUSEADDR cohabitation

[uclinux-h8/linux.git] / net / ipv4 / inet_connection_sock.c

diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
index b95fb26..60021d0 100644 (file)
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
@@ -99,6 +99,7 @@ int inet_csk_get_port(struct sock *sk, unsigned short snum)
        struct net *net = sock_net(sk);
        int smallest_size = -1, smallest_rover;
        kuid_t uid = sock_i_uid(sk);
+       int attempt_half = (sk->sk_reuse == SK_CAN_REUSE) ? 1 : 0;
 
        local_bh_disable();
        if (!snum) {
@@ -106,6 +107,14 @@ int inet_csk_get_port(struct sock *sk, unsigned short snum)
 
 again:
                inet_get_local_port_range(net, &low, &high);
+               if (attempt_half) {
+                       int half = low + ((high - low) >> 1);
+
+                       if (attempt_half == 1)
+                               high = half;
+                       else
+                               low = half;
+               }
                remaining = (high - low) + 1;
                smallest_rover = rover = prandom_u32() % remaining + low;
 
@@ -154,6 +163,11 @@ again:
                                snum = smallest_rover;
                                goto have_snum;
                        }
+                       if (attempt_half == 1) {
+                               /* OK we now try the upper half of the range */
+                               attempt_half = 2;
+                               goto again;
+                       }
                        goto fail;
                }
                /* OK, here is the one we will use.  HEAD is