ipv4: send arp replies to the correct tunnel
When using ip lwtunnels, the additional data for xmit (basically, the actual
tunnel to use) are carried in ip_tunnel_info either in dst->lwtstate or in
metadata dst. When replying to ARP requests, we need to send the reply to
the same tunnel the request came from. This means we need to construct
proper metadata dst for ARP replies.
We could perform another route lookup to get a dst entry with the correct
lwtstate. However, this won't always ensure that the outgoing tunnel is the
same as the incoming one, and it won't work anyway for IPv4 duplicate
address detection.
The only thing to do is to "reverse" the ip_tunnel_info.
Signed-off-by: Jiri Benc <jbenc@redhat.com>
Acked-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/ip_tunnels.h b/include/net/ip_tunnels.h
index 9a6a3ba..f6dafec 100644
--- a/include/net/ip_tunnels.h
+++ b/include/net/ip_tunnels.h
@@ -276,6 +276,8 @@
int iptunnel_xmit(struct sock *sk, struct rtable *rt, struct sk_buff *skb,
__be32 src, __be32 dst, u8 proto,
u8 tos, u8 ttl, __be16 df, bool xnet);
+struct metadata_dst *iptunnel_metadata_reply(struct metadata_dst *md,
+ gfp_t flags);
struct sk_buff *iptunnel_handle_offloads(struct sk_buff *skb, bool gre_csum,
int gso_type_mask);
diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c
index 30409b7..f03db8b 100644
--- a/net/ipv4/arp.c
+++ b/net/ipv4/arp.c
@@ -113,6 +113,8 @@
#include <net/arp.h>
#include <net/ax25.h>
#include <net/netrom.h>
+#include <net/dst_metadata.h>
+#include <net/ip_tunnels.h>
#include <linux/uaccess.h>
@@ -296,7 +298,8 @@
struct net_device *dev, __be32 src_ip,
const unsigned char *dest_hw,
const unsigned char *src_hw,
- const unsigned char *target_hw, struct sk_buff *oskb)
+ const unsigned char *target_hw,
+ struct dst_entry *dst)
{
struct sk_buff *skb;
@@ -309,9 +312,7 @@
if (!skb)
return;
- if (oskb)
- skb_dst_copy(skb, oskb);
-
+ skb_dst_set(skb, dst);
arp_xmit(skb);
}
@@ -333,6 +334,7 @@
__be32 target = *(__be32 *)neigh->primary_key;
int probes = atomic_read(&neigh->probes);
struct in_device *in_dev;
+ struct dst_entry *dst = NULL;
rcu_read_lock();
in_dev = __in_dev_get_rcu(dev);
@@ -381,9 +383,10 @@
}
}
+ if (skb && !(dev->priv_flags & IFF_XMIT_DST_RELEASE))
+ dst = dst_clone(skb_dst(skb));
arp_send_dst(ARPOP_REQUEST, ETH_P_ARP, target, dev, saddr,
- dst_hw, dev->dev_addr, NULL,
- dev->priv_flags & IFF_XMIT_DST_RELEASE ? NULL : skb);
+ dst_hw, dev->dev_addr, NULL, dst);
}
static int arp_ignore(struct in_device *in_dev, __be32 sip, __be32 tip)
@@ -649,6 +652,7 @@
int addr_type;
struct neighbour *n;
struct net *net = dev_net(dev);
+ struct dst_entry *reply_dst = NULL;
bool is_garp = false;
/* arp_rcv below verifies the ARP header and verifies the device
@@ -749,13 +753,18 @@
* cache.
*/
+ if (arp->ar_op == htons(ARPOP_REQUEST) && skb_metadata_dst(skb))
+ reply_dst = (struct dst_entry *)
+ iptunnel_metadata_reply(skb_metadata_dst(skb),
+ GFP_ATOMIC);
+
/* Special case: IPv4 duplicate address detection packet (RFC2131) */
if (sip == 0) {
if (arp->ar_op == htons(ARPOP_REQUEST) &&
inet_addr_type_dev_table(net, dev, tip) == RTN_LOCAL &&
!arp_ignore(in_dev, sip, tip))
- arp_send(ARPOP_REPLY, ETH_P_ARP, sip, dev, tip, sha,
- dev->dev_addr, sha);
+ arp_send_dst(ARPOP_REPLY, ETH_P_ARP, sip, dev, tip,
+ sha, dev->dev_addr, sha, reply_dst);
goto out;
}
@@ -774,9 +783,10 @@
if (!dont_send) {
n = neigh_event_ns(&arp_tbl, sha, &sip, dev);
if (n) {
- arp_send(ARPOP_REPLY, ETH_P_ARP, sip,
- dev, tip, sha, dev->dev_addr,
- sha);
+ arp_send_dst(ARPOP_REPLY, ETH_P_ARP,
+ sip, dev, tip, sha,
+ dev->dev_addr, sha,
+ reply_dst);
neigh_release(n);
}
}
@@ -794,9 +804,10 @@
if (NEIGH_CB(skb)->flags & LOCALLY_ENQUEUED ||
skb->pkt_type == PACKET_HOST ||
NEIGH_VAR(in_dev->arp_parms, PROXY_DELAY) == 0) {
- arp_send(ARPOP_REPLY, ETH_P_ARP, sip,
- dev, tip, sha, dev->dev_addr,
- sha);
+ arp_send_dst(ARPOP_REPLY, ETH_P_ARP,
+ sip, dev, tip, sha,
+ dev->dev_addr, sha,
+ reply_dst);
} else {
pneigh_enqueue(&arp_tbl,
in_dev->arp_parms, skb);
diff --git a/net/ipv4/ip_tunnel_core.c b/net/ipv4/ip_tunnel_core.c
index 9b97204..ce3a1e7 100644
--- a/net/ipv4/ip_tunnel_core.c
+++ b/net/ipv4/ip_tunnel_core.c
@@ -46,6 +46,7 @@
#include <net/net_namespace.h>
#include <net/netns/generic.h>
#include <net/rtnetlink.h>
+#include <net/dst_metadata.h>
int iptunnel_xmit(struct sock *sk, struct rtable *rt, struct sk_buff *skb,
__be32 src, __be32 dst, __u8 proto,
@@ -119,6 +120,33 @@
}
EXPORT_SYMBOL_GPL(iptunnel_pull_header);
+struct metadata_dst *iptunnel_metadata_reply(struct metadata_dst *md,
+ gfp_t flags)
+{
+ struct metadata_dst *res;
+ struct ip_tunnel_info *dst, *src;
+
+ if (!md || md->u.tun_info.mode & IP_TUNNEL_INFO_TX)
+ return NULL;
+
+ res = metadata_dst_alloc(0, flags);
+ if (!res)
+ return NULL;
+
+ dst = &res->u.tun_info;
+ src = &md->u.tun_info;
+ dst->key.tun_id = src->key.tun_id;
+ if (src->mode & IP_TUNNEL_INFO_IPV6)
+ memcpy(&dst->key.u.ipv6.dst, &src->key.u.ipv6.src,
+ sizeof(struct in6_addr));
+ else
+ dst->key.u.ipv4.dst = src->key.u.ipv4.src;
+ dst->mode = src->mode | IP_TUNNEL_INFO_TX;
+
+ return res;
+}
+EXPORT_SYMBOL_GPL(iptunnel_metadata_reply);
+
struct sk_buff *iptunnel_handle_offloads(struct sk_buff *skb,
bool csum_help,
int gso_type_mask)