net: tcp: Permit user set TCP_MAXSEG to default value
authorGao Feng <fgao@ikuai8.com>
Tue, 21 Mar 2017 01:28:03 +0000 (09:28 +0800)
committerDavid S. Miller <davem@davemloft.net>
Wed, 22 Mar 2017 18:45:13 +0000 (11:45 -0700)
When user_mss is zero, it means use the default value. But the current
codes don't permit user set TCP_MAXSEG to the default value.
It would return the -EINVAL when val is zero.

Signed-off-by: Gao Feng <fgao@ikuai8.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/ipv4/tcp.c

index cf4555581282c608f920254078264e36e18584c6..eccec53ef1008040ebe306b0e04ba273d03c7973 100644 (file)
@@ -2470,7 +2470,7 @@ static int do_tcp_setsockopt(struct sock *sk, int level,
                /* Values greater than interface MTU won't take effect. However
                 * at the point when this call is done we typically don't yet
                 * know which interface is going to be used */
-               if (val < TCP_MIN_MSS || val > MAX_TCP_WINDOW) {
+               if (val && (val < TCP_MIN_MSS || val > MAX_TCP_WINDOW)) {
                        err = -EINVAL;
                        break;
                }