[PATCH 3.16 01/17] ip_tunnel(ipv4): fix tunnels with "local any remote $remote_ip"

From: Greg Kroah-Hartman
Date: Fri Aug 08 2014 - 17:41:34 EST


3.16-stable review patch. If anyone has any objections, please let me know.

------------------

From: Dmitry Popov <ixaphire@xxxxxxxxxx>

[ Upstream commit 95cb5745983c222867cc9ac593aebb2ad67d72c0 ]

Ipv4 tunnels created with "local any remote $ip" didn't work properly since
7d442fab0 (ipv4: Cache dst in tunnels). 99% of packets sent via those tunnels
had src addr = 0.0.0.0. That was because only dst_entry was cached, although
fl4.saddr has to be cached too. Every time ip_tunnel_xmit used cached dst_entry
(tunnel_rtable_get returned non-NULL), fl4.saddr was initialized with
tnl_params->saddr (= 0 in our case), and wasn't changed until iptunnel_xmit().

This patch adds saddr to ip_tunnel->dst_cache, fixing this issue.

Reported-by: Sergey Popov <pinkbyte@xxxxxxxxxx>
Signed-off-by: Dmitry Popov <ixaphire@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
include/net/ip_tunnels.h | 1 +
net/ipv4/ip_tunnel.c | 29 ++++++++++++++++++-----------
2 files changed, 19 insertions(+), 11 deletions(-)

--- a/include/net/ip_tunnels.h
+++ b/include/net/ip_tunnels.h
@@ -40,6 +40,7 @@ struct ip_tunnel_prl_entry {

struct ip_tunnel_dst {
struct dst_entry __rcu *dst;
+ __be32 saddr;
};

struct ip_tunnel {
--- a/net/ipv4/ip_tunnel.c
+++ b/net/ipv4/ip_tunnel.c
@@ -69,23 +69,25 @@ static unsigned int ip_tunnel_hash(__be3
}

static void __tunnel_dst_set(struct ip_tunnel_dst *idst,
- struct dst_entry *dst)
+ struct dst_entry *dst, __be32 saddr)
{
struct dst_entry *old_dst;

dst_clone(dst);
old_dst = xchg((__force struct dst_entry **)&idst->dst, dst);
dst_release(old_dst);
+ idst->saddr = saddr;
}

-static void tunnel_dst_set(struct ip_tunnel *t, struct dst_entry *dst)
+static void tunnel_dst_set(struct ip_tunnel *t,
+ struct dst_entry *dst, __be32 saddr)
{
- __tunnel_dst_set(this_cpu_ptr(t->dst_cache), dst);
+ __tunnel_dst_set(this_cpu_ptr(t->dst_cache), dst, saddr);
}

static void tunnel_dst_reset(struct ip_tunnel *t)
{
- tunnel_dst_set(t, NULL);
+ tunnel_dst_set(t, NULL, 0);
}

void ip_tunnel_dst_reset_all(struct ip_tunnel *t)
@@ -93,20 +95,25 @@ void ip_tunnel_dst_reset_all(struct ip_t
int i;

for_each_possible_cpu(i)
- __tunnel_dst_set(per_cpu_ptr(t->dst_cache, i), NULL);
+ __tunnel_dst_set(per_cpu_ptr(t->dst_cache, i), NULL, 0);
}
EXPORT_SYMBOL(ip_tunnel_dst_reset_all);

-static struct rtable *tunnel_rtable_get(struct ip_tunnel *t, u32 cookie)
+static struct rtable *tunnel_rtable_get(struct ip_tunnel *t,
+ u32 cookie, __be32 *saddr)
{
+ struct ip_tunnel_dst *idst;
struct dst_entry *dst;

rcu_read_lock();
- dst = rcu_dereference(this_cpu_ptr(t->dst_cache)->dst);
+ idst = this_cpu_ptr(t->dst_cache);
+ dst = rcu_dereference(idst->dst);
if (dst && !atomic_inc_not_zero(&dst->__refcnt))
dst = NULL;
if (dst) {
- if (dst->obsolete && dst->ops->check(dst, cookie) == NULL) {
+ if (!dst->obsolete || dst->ops->check(dst, cookie)) {
+ *saddr = idst->saddr;
+ } else {
tunnel_dst_reset(t);
dst_release(dst);
dst = NULL;
@@ -367,7 +374,7 @@ static int ip_tunnel_bind_dev(struct net

if (!IS_ERR(rt)) {
tdev = rt->dst.dev;
- tunnel_dst_set(tunnel, &rt->dst);
+ tunnel_dst_set(tunnel, &rt->dst, fl4.saddr);
ip_rt_put(rt);
}
if (dev->type != ARPHRD_ETHER)
@@ -610,7 +617,7 @@ void ip_tunnel_xmit(struct sk_buff *skb,
init_tunnel_flow(&fl4, protocol, dst, tnl_params->saddr,
tunnel->parms.o_key, RT_TOS(tos), tunnel->parms.link);

- rt = connected ? tunnel_rtable_get(tunnel, 0) : NULL;
+ rt = connected ? tunnel_rtable_get(tunnel, 0, &fl4.saddr) : NULL;

if (!rt) {
rt = ip_route_output_key(tunnel->net, &fl4);
@@ -620,7 +627,7 @@ void ip_tunnel_xmit(struct sk_buff *skb,
goto tx_error;
}
if (connected)
- tunnel_dst_set(tunnel, &rt->dst);
+ tunnel_dst_set(tunnel, &rt->dst, fl4.saddr);
}

if (rt->dst.dev == dev) {


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