Re: [PATCH] ip6_tunnel: allow to change mode for the ip6tnl0
From: Eric Dumazet <hidden>
Date: 2014-10-29 06:46:54
Subsystem:
networking [general], networking [ipv4/ipv6], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, David Ahern, Ido Schimmel, Linus Torvalds
On Wed, 2014-10-29 at 09:24 +0300, Alexey Andriyanov wrote: ...
The fallback device can not be hidden from the packet receiver as a regular tunnel, but there is no need for synchronization as long as we do single assignment.
This is not exact, I believe you need to add following changes : net/ipv6/ip6_tunnel.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-)
diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index 9409887fb664dd78d13937b89ea1b5044afdbc94..9d43b99073d656a5a8a38976ca593a41b3cbdca4 100644
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c@@ -477,6 +477,7 @@ ip6_tnl_err(struct sk_buff *skb, __u8 ipproto, struct inet6_skb_parm *opt, int rel_msg = 0; u8 rel_type = ICMPV6_DEST_UNREACH; u8 rel_code = ICMPV6_ADDR_UNREACH; + u8 tproto; __u32 rel_info = 0; __u16 len; int err = -ENOENT;
@@ -490,7 +491,8 @@ ip6_tnl_err(struct sk_buff *skb, __u8 ipproto, struct inet6_skb_parm *opt, &ipv6h->saddr)) == NULL) goto out; - if (t->parms.proto != ipproto && t->parms.proto != 0) + tproto = ACCESS_ONCE(t->parms.proto); + if (tproto != ipproto && tproto != 0) goto out; err = 0;
@@ -791,6 +793,7 @@ static int ip6_tnl_rcv(struct sk_buff *skb, __u16 protocol, { struct ip6_tnl *t; const struct ipv6hdr *ipv6h = ipv6_hdr(skb); + u8 tproto; int err; rcu_read_lock();
@@ -799,7 +802,8 @@ static int ip6_tnl_rcv(struct sk_buff *skb, __u16 protocol, &ipv6h->daddr)) != NULL) { struct pcpu_sw_netstats *tstats; - if (t->parms.proto != ipproto && t->parms.proto != 0) { + tproto = ACCESS_ONCE(t->parms.proto); + if (tproto != ipproto && tproto != 0) { rcu_read_unlock(); goto discard; }
@@ -1078,9 +1082,11 @@ ip4ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev) struct flowi6 fl6; __u8 dsfield; __u32 mtu; + u8 tproto; int err; - if ((t->parms.proto != IPPROTO_IPIP && t->parms.proto != 0) || + tproto = ACCESS_ONCE(t->parms.proto); + if ((tproto != IPPROTO_IPIP && tproto != 0) || !ip6_tnl_xmit_ctl(t)) return -1;
@@ -1120,9 +1126,11 @@ ip6ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev) struct flowi6 fl6; __u8 dsfield; __u32 mtu; + u8 tproto; int err; - if ((t->parms.proto != IPPROTO_IPV6 && t->parms.proto != 0) || + tproto = ACCESS_ONCE(t->parms.proto); + if ((tproto != IPPROTO_IPV6 && tproto != 0) || !ip6_tnl_xmit_ctl(t) || ip6_tnl_addr_conflict(t, ipv6h)) return -1;