[SK_BUFF]: Introduce skb_network_header()

For the places where we need a pointer to the network header, it is still legal
to touch skb->nh.raw directly if just adding to, subtracting from or setting it
to another layer header.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 13 insertions, 10 deletions

diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 47d0021..f1dfcc3 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -323,10 +323,11 @@ static int ip6_forward_proxy_check(struct sk_buff *skb)
 	if (nexthdr == IPPROTO_ICMPV6) {
 		struct icmp6hdr *icmp6;
 
-		if (!pskb_may_pull(skb, skb->nh.raw + offset + 1 - skb->data))
+		if (!pskb_may_pull(skb, (skb_network_header(skb) +
+					 offset + 1 - skb->data)))
 			return 0;
 
-		icmp6 = (struct icmp6hdr *)(skb->nh.raw + offset);
+		icmp6 = (struct icmp6hdr *)(skb_network_header(skb) + offset);
 
 		switch (icmp6->icmp6_type) {
 		case NDISC_ROUTER_SOLICITATION:
@@ -392,7 +393,7 @@ int ip6_forward(struct sk_buff *skb)
 	 *	that different fragments will go along one path. --ANK
 	 */
 	if (opt->ra) {
-		u8 *ptr = skb->nh.raw + opt->ra;
+		u8 *ptr = skb_network_header(skb) + opt->ra;
 		if (ip6_call_ra_chain(skb, (ptr[2]<<8) + ptr[3]))
 			return 0;
 	}
@@ -527,7 +528,7 @@ int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr)
 {
 	u16 offset = sizeof(struct ipv6hdr);
 	struct ipv6_opt_hdr *exthdr = (struct ipv6_opt_hdr*)(skb->nh.ipv6h + 1);
-	unsigned int packet_len = skb->tail - skb->nh.raw;
+	unsigned int packet_len = skb->tail - skb_network_header(skb);
 	int found_rhdr = 0;
 	*nexthdr = &skb->nh.ipv6h->nexthdr;
 
@@ -554,7 +555,8 @@ int ip6_find_1stfragopt(struct sk_buff *skb, u8 **nexthdr)
 
 		offset += ipv6_optlen(exthdr);
 		*nexthdr = &exthdr->nexthdr;
-		exthdr = (struct ipv6_opt_hdr*)(skb->nh.raw + offset);
+		exthdr = (struct ipv6_opt_hdr *)(skb_network_header(skb) +
+						 offset);
 	}
 
 	return offset;
@@ -620,7 +622,7 @@ static int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *))
 		/* BUILD HEADER */
 
 		*prevhdr = NEXTHDR_FRAGMENT;
-		tmp_hdr = kmemdup(skb->nh.raw, hlen, GFP_ATOMIC);
+		tmp_hdr = kmemdup(skb_network_header(skb), hlen, GFP_ATOMIC);
 		if (!tmp_hdr) {
 			IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_FRAGFAILS);
 			return -ENOMEM;
@@ -630,7 +632,7 @@ static int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *))
 		fh = (struct frag_hdr*)__skb_push(skb, sizeof(struct frag_hdr));
 		__skb_push(skb, hlen);
 		skb_reset_network_header(skb);
-		memcpy(skb->nh.raw, tmp_hdr, hlen);
+		memcpy(skb_network_header(skb), tmp_hdr, hlen);
 
 		ipv6_select_ident(skb, fh);
 		fh->nexthdr = nexthdr;
@@ -654,7 +656,8 @@ static int ip6_fragment(struct sk_buff *skb, int (*output)(struct sk_buff *))
 				fh = (struct frag_hdr*)__skb_push(frag, sizeof(struct frag_hdr));
 				__skb_push(frag, hlen);
 				skb_reset_network_header(frag);
-				memcpy(frag->nh.raw, tmp_hdr, hlen);
+				memcpy(skb_network_header(frag), tmp_hdr,
+				       hlen);
 				offset += skb->len - hlen - sizeof(struct frag_hdr);
 				fh->nexthdr = nexthdr;
 				fh->reserved = 0;
@@ -753,7 +756,7 @@ slow_path:
 		/*
 		 *	Copy the packet header into the new buffer.
 		 */
-		memcpy(frag->nh.raw, skb->data, hlen);
+		memcpy(skb_network_header(frag), skb->data, hlen);
 
 		/*
 		 *	Build fragment header.
@@ -1329,7 +1332,7 @@ int ip6_push_pending_frames(struct sock *sk)
 	tail_skb = &(skb_shinfo(skb)->frag_list);
 
 	/* move skb->data to ip header from ext header */
-	if (skb->data < skb->nh.raw)
+	if (skb->data < skb_network_header(skb))
 		__skb_pull(skb, skb_network_offset(skb));
 	while ((tmp_skb = __skb_dequeue(&sk->sk_write_queue)) != NULL) {
 		__skb_pull(tmp_skb, skb->h.raw - skb->nh.raw);