[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, 33 insertions, 23 deletions

diff --git a/net/ipv6/exthdrs.c b/net/ipv6/exthdrs.c
index fce5abd..9ebf120 100644
--- a/net/ipv6/exthdrs.c
+++ b/net/ipv6/exthdrs.c
@@ -50,13 +50,14 @@
 
 int ipv6_find_tlv(struct sk_buff *skb, int offset, int type)
 {
-	int packet_len = skb->tail - skb->nh.raw;
+	const unsigned char *nh = skb_network_header(skb);
+	int packet_len = skb->tail - nh;
 	struct ipv6_opt_hdr *hdr;
 	int len;
 
 	if (offset + 2 > packet_len)
 		goto bad;
-	hdr = (struct ipv6_opt_hdr*)(skb->nh.raw + offset);
+	hdr = (struct ipv6_opt_hdr *)(nh + offset);
 	len = ((hdr->hdrlen + 1) << 3);
 
 	if (offset + len > packet_len)
@@ -66,7 +67,7 @@ int ipv6_find_tlv(struct sk_buff *skb, int offset, int type)
 	len -= 2;
 
 	while (len > 0) {
-		int opttype = skb->nh.raw[offset];
+		int opttype = nh[offset];
 		int optlen;
 
 		if (opttype == type)
@@ -77,7 +78,7 @@ int ipv6_find_tlv(struct sk_buff *skb, int offset, int type)
 			optlen = 1;
 			break;
 		default:
-			optlen = skb->nh.raw[offset + 1] + 2;
+			optlen = nh[offset + 1] + 2;
 			if (optlen > len)
 				goto bad;
 			break;
@@ -113,7 +114,7 @@ static int ip6_tlvopt_unknown(struct sk_buff **skbp, int optoff)
 {
 	struct sk_buff *skb = *skbp;
 
-	switch ((skb->nh.raw[optoff] & 0xC0) >> 6) {
+	switch ((skb_network_header(skb)[optoff] & 0xC0) >> 6) {
 	case 0: /* ignore */
 		return 1;
 
@@ -141,6 +142,7 @@ static int ip6_parse_tlv(struct tlvtype_proc *procs, struct sk_buff **skbp)
 {
 	struct sk_buff *skb = *skbp;
 	struct tlvtype_proc *curr;
+	const unsigned char *nh = skb_network_header(skb);
 	int off = skb->h.raw - skb->nh.raw;
 	int len = ((skb->h.raw[1]+1)<<3);
 
@@ -151,9 +153,9 @@ static int ip6_parse_tlv(struct tlvtype_proc *procs, struct sk_buff **skbp)
 	len -= 2;
 
 	while (len > 0) {
-		int optlen = skb->nh.raw[off+1]+2;
+		int optlen = nh[off + 1] + 2;
 
-		switch (skb->nh.raw[off]) {
+		switch (nh[off]) {
 		case IPV6_TLV_PAD0:
 			optlen = 1;
 			break;
@@ -165,7 +167,7 @@ static int ip6_parse_tlv(struct tlvtype_proc *procs, struct sk_buff **skbp)
 			if (optlen > len)
 				goto bad;
 			for (curr=procs; curr->type >= 0; curr++) {
-				if (curr->type == skb->nh.raw[off]) {
+				if (curr->type == nh[off]) {
 					/* type specific length/alignment
 					   checks will be performed in the
 					   func(). */
@@ -211,7 +213,7 @@ static int ipv6_dest_hao(struct sk_buff **skbp, int optoff)
 	opt->dsthao = opt->dst1;
 	opt->dst1 = 0;
 
-	hao = (struct ipv6_destopt_hao *)(skb->nh.raw + optoff);
+	hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) + optoff);
 
 	if (hao->length != 16) {
 		LIMIT_NETDEBUG(
@@ -244,8 +246,9 @@ static int ipv6_dest_hao(struct sk_buff **skbp, int optoff)
 
 		/* update all variable using below by copied skbuff */
 		*skbp = skb = skb2;
-		hao = (struct ipv6_destopt_hao *)(skb2->nh.raw + optoff);
-		ipv6h = (struct ipv6hdr *)skb2->nh.raw;
+		hao = (struct ipv6_destopt_hao *)(skb_network_header(skb2) +
+						  optoff);
+		ipv6h = skb2->nh.ipv6h;
 	}
 
 	if (skb->ip_summed == CHECKSUM_COMPLETE)
@@ -406,7 +409,8 @@ static int ipv6_rthdr_rcv(struct sk_buff **skbp)
 	default:
 		IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 				 IPSTATS_MIB_INHDRERRORS);
-		icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, (&hdr->type) - skb->nh.raw);
+		icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
+				  (&hdr->type) - skb_network_header(skb));
 		return -1;
 	}
 
@@ -443,7 +447,7 @@ looped_back:
 		skb->h.raw += (hdr->hdrlen + 1) << 3;
 		opt->dst0 = opt->dst1;
 		opt->dst1 = 0;
-		opt->nhoff = (&hdr->nexthdr) - skb->nh.raw;
+		opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
 		return 1;
 	}
 
@@ -452,7 +456,9 @@ looped_back:
 		if (hdr->hdrlen & 0x01) {
 			IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 					 IPSTATS_MIB_INHDRERRORS);
-			icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, (&hdr->hdrlen) - skb->nh.raw);
+			icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
+					  ((&hdr->hdrlen) -
+					   skb_network_header(skb)));
 			return -1;
 		}
 		break;
@@ -479,7 +485,9 @@ looped_back:
 	if (hdr->segments_left > n) {
 		IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 				 IPSTATS_MIB_INHDRERRORS);
-		icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, (&hdr->segments_left) - skb->nh.raw);
+		icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
+				  ((&hdr->segments_left) -
+				   skb_network_header(skb)));
 		return -1;
 	}
 
@@ -547,7 +555,7 @@ looped_back:
 	dst_release(xchg(&skb->dst, NULL));
 	ip6_route_input(skb);
 	if (skb->dst->error) {
-		skb_push(skb, skb->data - skb->nh.raw);
+		skb_push(skb, skb->data - skb_network_header(skb));
 		dst_input(skb);
 		return -1;
 	}
@@ -565,7 +573,7 @@ looped_back:
 		goto looped_back;
 	}
 
-	skb_push(skb, skb->data - skb->nh.raw);
+	skb_push(skb, skb->data - skb_network_header(skb));
 	dst_input(skb);
 	return -1;
 }
@@ -656,13 +664,14 @@ EXPORT_SYMBOL_GPL(ipv6_invert_rthdr);
 static int ipv6_hop_ra(struct sk_buff **skbp, int optoff)
 {
 	struct sk_buff *skb = *skbp;
+	const unsigned char *nh = skb_network_header(skb);
 
-	if (skb->nh.raw[optoff+1] == 2) {
+	if (nh[optoff + 1] == 2) {
 		IP6CB(skb)->ra = optoff;
 		return 1;
 	}
 	LIMIT_NETDEBUG(KERN_DEBUG "ipv6_hop_ra: wrong RA length %d\n",
-		       skb->nh.raw[optoff+1]);
+		       nh[optoff + 1]);
 	kfree_skb(skb);
 	return 0;
 }
@@ -672,17 +681,18 @@ static int ipv6_hop_ra(struct sk_buff **skbp, int optoff)
 static int ipv6_hop_jumbo(struct sk_buff **skbp, int optoff)
 {
 	struct sk_buff *skb = *skbp;
+	const unsigned char *nh = skb_network_header(skb);
 	u32 pkt_len;
 
-	if (skb->nh.raw[optoff+1] != 4 || (optoff&3) != 2) {
+	if (nh[optoff + 1] != 4 || (optoff & 3) != 2) {
 		LIMIT_NETDEBUG(KERN_DEBUG "ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n",
-			       skb->nh.raw[optoff+1]);
+			       nh[optoff+1]);
 		IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 				 IPSTATS_MIB_INHDRERRORS);
 		goto drop;
 	}
 
-	pkt_len = ntohl(*(__be32*)(skb->nh.raw+optoff+2));
+	pkt_len = ntohl(*(__be32 *)(nh + optoff + 2));
 	if (pkt_len <= IPV6_MAXPLEN) {
 		IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_INHDRERRORS);
 		icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff+2);
@@ -727,7 +737,7 @@ int ipv6_parse_hopopts(struct sk_buff **skbp)
 	struct inet6_skb_parm *opt = IP6CB(skb);
 
 	/*
-	 * skb->nh.raw is equal to skb->data, and
+	 * skb_network_header(skb) is equal to skb->data, and
 	 * skb->h.raw - skb->nh.raw is always equal to
 	 * sizeof(struct ipv6hdr) by definition of
 	 * hop-by-hop options.