[SK_BUFF]: Introduce skb_transport_header(skb)

For the places where we need a pointer to the transport header, it is
still legal to touch skb->h.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>

9 files changed, 31 insertions, 23 deletions

diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c
index 292516b..8f0df7b 100644
--- a/net/ipv4/igmp.c
+++ b/net/ipv4/igmp.c
@@ -348,7 +348,7 @@ static int igmpv3_sendpack(struct sk_buff *skb)
 	struct iphdr *pip = ip_hdr(skb);
 	struct igmphdr *pig = igmp_hdr(skb);
 	const int iplen = skb->tail - skb->nh.raw;
-	const int igmplen = skb->tail - skb->h.raw;
+	const int igmplen = skb->tail - skb_transport_header(skb);
 
 	pip->tot_len = htons(iplen);
 	ip_send_check(pip);
diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index 39216e6..e6a9e45 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -619,7 +619,7 @@ static int ipgre_rcv(struct sk_buff *skb)
 		skb_reset_mac_header(skb);
 		__pskb_pull(skb, offset);
 		skb_reset_network_header(skb);
-		skb_postpull_rcsum(skb, skb->h.raw, offset);
+		skb_postpull_rcsum(skb, skb_transport_header(skb), offset);
 		skb->pkt_type = PACKET_HOST;
 #ifdef CONFIG_NET_IPGRE_BROADCAST
 		if (MULTICAST(iph->daddr)) {
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index 6022686..11029b9 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -1128,7 +1128,7 @@ ssize_t	ip_append_page(struct sock *sk, struct page *page,
 			if (fraggap) {
 				skb->csum = skb_copy_and_csum_bits(skb_prev,
 								   maxfraglen,
-								   skb->h.raw,
+						    skb_transport_header(skb),
 								   fraggap, 0);
 				skb_prev->csum = csum_sub(skb_prev->csum,
 							  skb->csum);
@@ -1374,7 +1374,9 @@ void ip_send_reply(struct sock *sk, struct sk_buff *skb, struct ip_reply_arg *ar
 		       &ipc, rt, MSG_DONTWAIT);
 	if ((skb = skb_peek(&sk->sk_write_queue)) != NULL) {
 		if (arg->csumoffset >= 0)
-			*((__sum16 *)skb->h.raw + arg->csumoffset) = csum_fold(csum_add(skb->csum, arg->csum));
+			*((__sum16 *)skb_transport_header(skb) +
+			  arg->csumoffset) = csum_fold(csum_add(skb->csum,
+								arg->csum));
 		skb->ip_summed = CHECKSUM_NONE;
 		ip_push_pending_frames(sk);
 	}
diff --git a/net/ipv4/ipconfig.c b/net/ipv4/ipconfig.c
index 6b91c9f..4e19ee0 100644
--- a/net/ipv4/ipconfig.c
+++ b/net/ipv4/ipconfig.c
@@ -432,7 +432,7 @@ ic_rarp_recv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt
 		goto drop;
 
 	/* Basic sanity checks can be done without the lock.  */
-	rarp = (struct arphdr *)skb->h.raw;
+	rarp = (struct arphdr *)skb_transport_header(skb);
 
 	/* If this test doesn't pass, it's not IP, or we should
 	 * ignore it anyway.
@@ -455,7 +455,7 @@ ic_rarp_recv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt
 		goto drop;
 
 	/* OK, it is all there and looks valid, process... */
-	rarp = (struct arphdr *)skb->h.raw;
+	rarp = (struct arphdr *)skb_transport_header(skb);
 	rarp_ptr = (unsigned char *) (rarp + 1);
 
 	/* One reply at a time, please. */
diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index 05bc270..8f45c95 100644
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -1437,7 +1437,8 @@ int pim_rcv_v1(struct sk_buff * skb)
 	    pim->group != PIM_V1_VERSION || pim->code != PIM_V1_REGISTER)
 		goto drop;
 
-	encap = (struct iphdr*)(skb->h.raw + sizeof(struct igmphdr));
+	encap = (struct iphdr *)(skb_transport_header(skb) +
+				 sizeof(struct igmphdr));
 	/*
 	   Check that:
 	   a. packet is really destinted to a multicast group
@@ -1490,7 +1491,7 @@ static int pim_rcv(struct sk_buff * skb)
 	if (!pskb_may_pull(skb, sizeof(*pim) + sizeof(*encap)))
 		goto drop;
 
-	pim = (struct pimreghdr*)skb->h.raw;
+	pim = (struct pimreghdr *)skb_transport_header(skb);
 	if (pim->type != ((PIM_VERSION<<4)|(PIM_REGISTER)) ||
 	    (pim->flags&PIM_NULL_REGISTER) ||
 	    (ip_compute_csum((void *)pim, sizeof(*pim)) != 0 &&
@@ -1498,7 +1499,8 @@ static int pim_rcv(struct sk_buff * skb)
 		goto drop;
 
 	/* check if the inner packet is destined to mcast group */
-	encap = (struct iphdr*)(skb->h.raw + sizeof(struct pimreghdr));
+	encap = (struct iphdr *)(skb_transport_header(skb) +
+				 sizeof(struct pimreghdr));
 	if (!MULTICAST(encap->daddr) ||
 	    encap->tot_len == 0 ||
 	    ntohs(encap->tot_len) + sizeof(*pim) > skb->len)
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index f832f3c..2b214cc 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2219,8 +2219,9 @@ struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features)
 		th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
 				       (__force u32)delta));
 		if (skb->ip_summed != CHECKSUM_PARTIAL)
-			th->check = csum_fold(csum_partial(skb->h.raw, thlen,
-							   skb->csum));
+			th->check =
+			     csum_fold(csum_partial(skb_transport_header(skb),
+						    thlen, skb->csum));
 
 		seq += len;
 		skb = skb->next;
@@ -2230,12 +2231,13 @@ struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int features)
 		th->cwr = 0;
 	} while (skb->next);
 
-	delta = htonl(oldlen + (skb->tail - skb->h.raw) + skb->data_len);
+	delta = htonl(oldlen + (skb->tail - skb_transport_header(skb)) +
+		      skb->data_len);
 	th->check = ~csum_fold((__force __wsum)((__force u32)th->check +
 				(__force u32)delta));
 	if (skb->ip_summed != CHECKSUM_PARTIAL)
-		th->check = csum_fold(csum_partial(skb->h.raw, thlen,
-						   skb->csum));
+		th->check = csum_fold(csum_partial(skb_transport_header(skb),
+						   thlen, skb->csum));
 
 out:
 	return segs;
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index c1ce362..9c3b4c7 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -140,7 +140,7 @@ static void tcp_measure_rcv_mss(struct sock *sk,
 		 *
 		 * "len" is invariant segment length, including TCP header.
 		 */
-		len += skb->data - skb->h.raw;
+		len += skb->data - skb_transport_header(skb);
 		if (len >= TCP_MIN_RCVMSS + sizeof(struct tcphdr) ||
 		    /* If PSH is not set, packet should be
 		     * full sized, provided peer TCP is not badly broken.
@@ -940,7 +940,8 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
 {
 	const struct inet_connection_sock *icsk = inet_csk(sk);
 	struct tcp_sock *tp = tcp_sk(sk);
-	unsigned char *ptr = ack_skb->h.raw + TCP_SKB_CB(ack_skb)->sacked;
+	unsigned char *ptr = (skb_transport_header(ack_skb) +
+			      TCP_SKB_CB(ack_skb)->sacked);
 	struct tcp_sack_block_wire *sp = (struct tcp_sack_block_wire *)(ptr+2);
 	struct sk_buff *cached_skb;
 	int num_sacks = (ptr[1] - TCPOLEN_SACK_BASE)>>3;
@@ -3634,10 +3635,10 @@ tcp_collapse(struct sock *sk, struct sk_buff_head *list,
 			return;
 
 		skb_set_mac_header(nskb, skb_mac_header(skb) - skb->head);
-		skb_set_network_header(nskb,
-				       skb_network_header(skb) - skb->head);
-		skb_set_transport_header(nskb, skb->h.raw - skb->head);
-
+		skb_set_network_header(nskb, (skb_network_header(skb) -
+					      skb->head));
+		skb_set_transport_header(nskb, (skb_transport_header(skb) -
+						skb->head));
 		skb_reserve(nskb, header);
 		memcpy(nskb->head, skb->head, header);
 		memcpy(nskb->cb, skb->cb, sizeof(skb->cb));
diff --git a/net/ipv4/xfrm4_mode_beet.c b/net/ipv4/xfrm4_mode_beet.c
index 32fcfc0..591f0f1 100644
--- a/net/ipv4/xfrm4_mode_beet.c
+++ b/net/ipv4/xfrm4_mode_beet.c
@@ -51,7 +51,7 @@ static int xfrm4_beet_output(struct xfrm_state *x, struct sk_buff *skb)
 
 		BUG_ON(optlen < 0);
 
-		ph = (struct ip_beet_phdr *)skb->h.raw;
+		ph = (struct ip_beet_phdr *)skb_transport_header(skb);
 		ph->padlen = 4 - (optlen & 4);
 		ph->hdrlen = optlen / 8;
 		ph->nexthdr = top_iph->protocol;
diff --git a/net/ipv4/xfrm4_mode_transport.c b/net/ipv4/xfrm4_mode_transport.c
index 2c46cbb..dc8834e 100644
--- a/net/ipv4/xfrm4_mode_transport.c
+++ b/net/ipv4/xfrm4_mode_transport.c
@@ -45,10 +45,11 @@ static int xfrm4_transport_output(struct xfrm_state *x, struct sk_buff *skb)
  */
 static int xfrm4_transport_input(struct xfrm_state *x, struct sk_buff *skb)
 {
-	int ihl = skb->data - skb->h.raw;
+	int ihl = skb->data - skb_transport_header(skb);
 
 	if (skb->h.raw != skb->nh.raw) {
-		memmove(skb->h.raw, skb_network_header(skb), ihl);
+		memmove(skb_transport_header(skb),
+			skb_network_header(skb), ihl);
 		skb->nh.raw = skb->h.raw;
 	}
 	ip_hdr(skb)->tot_len = htons(skb->len + ihl);