From 513674b5a2c9c7a67501506419da5c3c77ac6f08 Mon Sep 17 00:00:00 2001 From: Shaohua Li Date: Wed, 20 Dec 2017 12:10:21 -0800 Subject: net: reevalulate autoflowlabel setting after sysctl setting sysctl.ip6.auto_flowlabels is default 1. In our hosts, we set it to 2. If sockopt doesn't set autoflowlabel, outcome packets from the hosts are supposed to not include flowlabel. This is true for normal packet, but not for reset packet. The reason is ipv6_pinfo.autoflowlabel is set in sock creation. Later if we change sysctl.ip6.auto_flowlabels, the ipv6_pinfo.autoflowlabel isn't changed, so the sock will keep the old behavior in terms of auto flowlabel. Reset packet is suffering from this problem, because reset packet is sent from a special control socket, which is created at boot time. Since sysctl.ipv6.auto_flowlabels is 1 by default, the control socket will always have its ipv6_pinfo.autoflowlabel set, even after user set sysctl.ipv6.auto_flowlabels to 1, so reset packset will always have flowlabel. Normal sock created before sysctl setting suffers from the same issue. We can't even turn off autoflowlabel unless we kill all socks in the hosts. To fix this, if IPV6_AUTOFLOWLABEL sockopt is used, we use the autoflowlabel setting from user, otherwise we always call ip6_default_np_autolabel() which has the new settings of sysctl. Note, this changes behavior a little bit. Before commit 42240901f7c4 (ipv6: Implement different admin modes for automatic flow labels), the autoflowlabel behavior of a sock isn't sticky, eg, if sysctl changes, existing connection will change autoflowlabel behavior. After that commit, autoflowlabel behavior is sticky in the whole life of the sock. With this patch, the behavior isn't sticky again. Cc: Martin KaFai Lau Cc: Eric Dumazet Cc: Tom Herbert Signed-off-by: Shaohua Li Signed-off-by: David S. Miller --- net/ipv6/ipv6_sockglue.c | 1 + 1 file changed, 1 insertion(+) (limited to 'net/ipv6/ipv6_sockglue.c') diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c index b9404feabd78..2d4680e0376f 100644 --- a/net/ipv6/ipv6_sockglue.c +++ b/net/ipv6/ipv6_sockglue.c @@ -886,6 +886,7 @@ pref_skip_coa: break; case IPV6_AUTOFLOWLABEL: np->autoflowlabel = valbool; + np->autoflowlabel_set = 1; retv = 0; break; case IPV6_RECVFRAGSIZE: -- cgit From e9191ffb65d8e159680ce0ad2224e1acbde6985c Mon Sep 17 00:00:00 2001 From: Ben Hutchings Date: Mon, 22 Jan 2018 20:06:42 +0000 Subject: ipv6: Fix getsockopt() for sockets with default IPV6_AUTOFLOWLABEL Commit 513674b5a2c9 ("net: reevalulate autoflowlabel setting after sysctl setting") removed the initialisation of ipv6_pinfo::autoflowlabel and added a second flag to indicate whether this field or the net namespace default should be used. The getsockopt() handling for this case was not updated, so it currently returns 0 for all sockets for which IPV6_AUTOFLOWLABEL is not explicitly enabled. Fix it to return the effective value, whether that has been set at the socket or net namespace level. Fixes: 513674b5a2c9 ("net: reevalulate autoflowlabel setting after sysctl ...") Signed-off-by: Ben Hutchings Signed-off-by: David S. Miller --- net/ipv6/ipv6_sockglue.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'net/ipv6/ipv6_sockglue.c') diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c index 2d4680e0376f..e8ffb5b5d84e 100644 --- a/net/ipv6/ipv6_sockglue.c +++ b/net/ipv6/ipv6_sockglue.c @@ -1336,7 +1336,7 @@ static int do_ipv6_getsockopt(struct sock *sk, int level, int optname, break; case IPV6_AUTOFLOWLABEL: - val = np->autoflowlabel; + val = ip6_autoflowlabel(sock_net(sk), np); break; case IPV6_RECVFRAGSIZE: -- cgit