From 0fbe82e628c817e292ff588cd5847fc935e025f2 Mon Sep 17 00:00:00 2001 From: yupeng Date: Wed, 5 Dec 2018 18:56:28 -0800 Subject: net: call sk_dst_reset when set SO_DONTROUTE after set SO_DONTROUTE to 1, the IP layer should not route packets if the dest IP address is not in link scope. But if the socket has cached the dst_entry, such packets would be routed until the sk_dst_cache expires. So we should clean the sk_dst_cache when a user set SO_DONTROUTE option. Below are server/client python scripts which could reprodue this issue: server side code: ========================================================================== import socket import struct import time s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) s.bind(('0.0.0.0', 9000)) s.listen(1) sock, addr = s.accept() sock.setsockopt(socket.SOL_SOCKET, socket.SO_DONTROUTE, struct.pack('i', 1)) while True: sock.send(b'foo') time.sleep(1) ========================================================================== client side code: ========================================================================== import socket import time s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) s.connect(('server_address', 9000)) while True: data = s.recv(1024) print(data) ========================================================================== Signed-off-by: yupeng Signed-off-by: David S. Miller --- net/core/sock.c | 1 + 1 file changed, 1 insertion(+) (limited to 'net/core/sock.c') diff --git a/net/core/sock.c b/net/core/sock.c index f5bb89785e47..f00902c532cc 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -700,6 +700,7 @@ int sock_setsockopt(struct socket *sock, int level, int optname, break; case SO_DONTROUTE: sock_valbool_flag(sk, SOCK_LOCALROUTE, valbool); + sk_dst_reset(sk); break; case SO_BROADCAST: sock_valbool_flag(sk, SOCK_BROADCAST, valbool); -- cgit v1.2.3-59-g8ed1b