Subject: Re: netfilter6: ICMPv6 type 143 doesn't match

From: Patrick McHardy <[email-masked]>
Date: Thu, 05 May 2005 21:53:36 +0200

Yasuyuki Kozakai wrote:

> Well, the Multicast Listener Report seems that skb->data != skb->nh.ipv6h
> when interface is up. But IPv6 netfilter modules assumes that
> skb->data == skb->nh.ipv6h like IPv4 netfilter modules.
> 
> folks, is this wrong or bad asumption ? If so, I'll fix this problem in
> many modules as follows.

Sorry for getting back to this so late, I must have missed it at the
time. Anyway, I think it would be safer to restore netfilters assumption
by doing something like this patch. If everyone is fine with it I'm
going to add it to my pending netfilter patches for 2.6.13.

Regards
Patrick
Index: net/ipv6/mcast.c
===================================================================
--- 2cfdb1827d9c176f4df42619c693e7b990a61963/net/ipv6/mcast.c  (mode:100644 sha1:393b6e6f50a9626e2894c9a5abd8dafd903e5eba)
+++ uncommitted/net/ipv6/mcast.c  (mode:100644)
@@ -1280,15 +1280,6 @@
 		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>:
@@ -1312,6 +1303,24 @@
 	return skb;
 }
 
+static inline int igmp6_dev_queue_xmit(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 void mld_sendpack(struct sk_buff *skb)
 {
 	struct ipv6hdr *pip6 = skb->nh.ipv6h;
@@ -1329,7 +1338,7 @@
 	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);
+		igmp6_dev_queue_xmit);
 	if (!err) {
 		ICMP6_INC_STATS(idev,ICMP6_MIB_OUTMSGS);
 		IP6_INC_STATS(IPSTATS_MIB_OUTMCASTPKTS);
@@ -1635,12 +1644,6 @@
 	}
 
 	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>:
@@ -1668,7 +1671,7 @@
 	idev = in6_dev_get(skb->dev);
 
 	err = NF_HOOK(PF_INET6, NF_IP6_LOCAL_OUT, skb, NULL, skb->dev,
-		dev_queue_xmit);
+		igmp6_dev_queue_xmit);
 	if (!err) {
 		if (type == ICMPV6_MGM_REDUCTION)
 			ICMP6_INC_STATS(idev, ICMP6_MIB_OUTGROUPMEMBREDUCTIONS);
@@ -1683,7 +1686,6 @@
 		in6_dev_put(idev);
 	return;
 
-out:
 	IP6_INC_STATS(IPSTATS_MIB_OUTDISCARDS);
 	kfree_skb(skb);
 }