[net,1/1] net: tcp: Permit user set TCP_MAXSEG to default value

Submitted by 高峰 on March 20, 2017, 9:30 p.m.

Details

Message ID 1490045417-32412-1-git-send-email-fgao@ikuai8.com
State Superseded
Delegated to: David Miller
Headers show

Commit Message

高峰 March 20, 2017, 9:30 p.m.
From: Gao Feng <fgao@ikuai8.com>

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>
---
 net/ipv4/tcp.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

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diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 1e319a5..dd5e8e2 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2470,7 +2470,8 @@  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 < 0 || (val > 0 && val < TCP_MIN_MSS) ||
+		    val > MAX_TCP_WINDOW) {
 			err = -EINVAL;
 			break;
 		}