[NETFILTER]: Restore netfilter assumptions in IPv6 multicast

Netfilter assumes that skb->data == skb->nh.ipv6h

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 26 insertions, 21 deletions

diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c
index c0ca92e8230b..562fcd14fdea 100644
--- a/net/ipv6/mcast.c
+++ b/net/ipv6/mcast.c
@@ -1301,15 +1301,6 @@ static struct sk_buff *mld_newpack(struct net_device *dev, int size)
                 return NULL;
 
         skb_reserve(skb, LL_RESERVED_SPACE(dev));
-        if (dev->hard_header) {
-                unsigned char ha[MAX_ADDR_LEN];
-
-                ndisc_mc_map(&mld2_all_mcr, ha, dev, 1);
-                if (dev->hard_header(skb, dev, ETH_P_IPV6,ha,NULL,size) < 0) {
-                        kfree_skb(skb);
-                        return NULL;
-                }
-        }
 
         if (ipv6_get_lladdr(dev, &addr_buf)) {
                 /* <draft-ietf-magma-mld-source-05.txt>:
@@ -1333,6 +1324,30 @@ static struct sk_buff *mld_newpack(struct net_device *dev, int size)
         return skb;
 }
 
+static inline int mld_dev_queue_xmit2(struct sk_buff *skb)
+{
+        struct net_device *dev = skb->dev;
+
+        if (dev->hard_header) {
+                unsigned char ha[MAX_ADDR_LEN];
+                int err;
+
+                ndisc_mc_map(&skb->nh.ipv6h->daddr, ha, dev, 1);
+                err = dev->hard_header(skb, dev, ETH_P_IPV6, ha, NULL, skb->len);
+                if (err < 0) {
+                        kfree_skb(skb);
+                        return err;
+                }
+        }
+        return dev_queue_xmit(skb);
+}
+
+static inline int mld_dev_queue_xmit(struct sk_buff *skb)
+{
+        return NF_HOOK(PF_INET6, NF_IP6_POST_ROUTING, skb, NULL, skb->dev,
+                       mld_dev_queue_xmit2);
+}
+
 static void mld_sendpack(struct sk_buff *skb)
 {
         struct ipv6hdr *pip6 = skb->nh.ipv6h;
@@ -1350,7 +1365,7 @@ static void mld_sendpack(struct sk_buff *skb)
         pmr->csum = csum_ipv6_magic(&pip6->saddr, &pip6->daddr, mldlen,
                 IPPROTO_ICMPV6, csum_partial(skb->h.raw, mldlen, 0));
         err = NF_HOOK(PF_INET6, NF_IP6_LOCAL_OUT, skb, NULL, skb->dev,
-                dev_queue_xmit);
+                mld_dev_queue_xmit);
         if (!err) {
                 ICMP6_INC_STATS(idev,ICMP6_MIB_OUTMSGS);
                 IP6_INC_STATS(IPSTATS_MIB_OUTMCASTPKTS);
@@ -1656,12 +1671,6 @@ static void igmp6_send(struct in6_addr *addr, struct net_device *dev, int type)
         }
 
         skb_reserve(skb, LL_RESERVED_SPACE(dev));
-        if (dev->hard_header) {
-                unsigned char ha[MAX_ADDR_LEN];
-                ndisc_mc_map(snd_addr, ha, dev, 1);
-                if (dev->hard_header(skb, dev, ETH_P_IPV6, ha, NULL, full_len) < 0)
-                        goto out;
-        }
 
         if (ipv6_get_lladdr(dev, &addr_buf)) {
                 /* <draft-ietf-magma-mld-source-05.txt>:
@@ -1689,7 +1698,7 @@ static void igmp6_send(struct in6_addr *addr, struct net_device *dev, int type)
         idev = in6_dev_get(skb->dev);
 
         err = NF_HOOK(PF_INET6, NF_IP6_LOCAL_OUT, skb, NULL, skb->dev,
-                dev_queue_xmit);
+                mld_dev_queue_xmit);
         if (!err) {
                 if (type == ICMPV6_MGM_REDUCTION)
                         ICMP6_INC_STATS(idev, ICMP6_MIB_OUTGROUPMEMBREDUCTIONS);
@@ -1703,10 +1712,6 @@ static void igmp6_send(struct in6_addr *addr, struct net_device *dev, int type)
         if (likely(idev != NULL))
                 in6_dev_put(idev);
         return;
-
-out:
-        IP6_INC_STATS(IPSTATS_MIB_OUTDISCARDS);
-        kfree_skb(skb);
 }
 
 static int ip6_mc_del1_src(struct ifmcaddr6 *pmc, int sfmode,