[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>

19 files changed, 43 insertions, 39 deletions

diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 6e5575b..ab552a6 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -1184,7 +1184,7 @@ static struct sk_buff *inet_gso_segment(struct sk_buff *skb, int features)
 		iph->id = htons(id++);
 		iph->tot_len = htons(skb->len - skb->mac_len);
 		iph->check = 0;
-		iph->check = ip_fast_csum(skb->nh.raw, iph->ihl);
+		iph->check = ip_fast_csum(skb_network_header(skb), iph->ihl);
 	} while ((skb = skb->next));
 
 out:
diff --git a/net/ipv4/ah4.c b/net/ipv4/ah4.c
index 7194eb4..95ddbbd 100644
--- a/net/ipv4/ah4.c
+++ b/net/ipv4/ah4.c
@@ -154,7 +154,7 @@ static int ah_input(struct xfrm_state *x, struct sk_buff *skb)
 	ah = (struct ip_auth_hdr*)skb->data;
 	iph = skb->nh.iph;
 
-	ihl = skb->data - skb->nh.raw;
+	ihl = skb->data - skb_network_header(skb);
 	memcpy(work_buf, iph, ihl);
 
 	iph->ttl = 0;
@@ -181,7 +181,8 @@ static int ah_input(struct xfrm_state *x, struct sk_buff *skb)
 		}
 	}
 	((struct iphdr*)work_buf)->protocol = ah->nexthdr;
-	skb->h.raw = memcpy(skb->nh.raw += ah_hlen, work_buf, ihl);
+	skb->nh.raw += ah_hlen;
+	skb->h.raw = memcpy(skb_network_header(skb), work_buf, ihl);
 	__skb_pull(skb, ah_hlen + ihl);
 
 	return 0;
diff --git a/net/ipv4/esp4.c b/net/ipv4/esp4.c
index 3104112..222d21e 100644
--- a/net/ipv4/esp4.c
+++ b/net/ipv4/esp4.c
@@ -57,9 +57,10 @@ static int esp_output(struct xfrm_state *x, struct sk_buff *skb)
 	*(u8*)(trailer->tail + clen-skb->len - 2) = (clen - skb->len)-2;
 	pskb_put(skb, trailer, clen - skb->len);
 
-	__skb_push(skb, skb->data - skb->nh.raw);
+	__skb_push(skb, skb->data - skb_network_header(skb));
 	top_iph = skb->nh.iph;
-	esph = (struct ip_esp_hdr *)(skb->nh.raw + top_iph->ihl*4);
+	esph = (struct ip_esp_hdr *)(skb_network_header(skb) +
+				     top_iph->ihl * 4);
 	top_iph->tot_len = htons(skb->len + alen);
 	*(u8*)(trailer->tail - 1) = top_iph->protocol;
 
@@ -222,7 +223,7 @@ static int esp_input(struct xfrm_state *x, struct sk_buff *skb)
 
 	if (x->encap) {
 		struct xfrm_encap_tmpl *encap = x->encap;
-		struct udphdr *uh = (void *)(skb->nh.raw + ihl);
+		struct udphdr *uh = (void *)(skb_network_header(skb) + ihl);
 
 		/*
 		 * 1) if the NAT-T peer's IP or port changed then
diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index 4b7a0d9..ff124d4 100644
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -484,7 +484,7 @@ void icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info)
 			u8 _inner_type, *itp;
 
 			itp = skb_header_pointer(skb_in,
-						 skb_in->nh.raw +
+						 skb_network_header(skb_in) +
 						 (iph->ihl << 2) +
 						 offsetof(struct icmphdr,
 							  type) -
@@ -536,7 +536,7 @@ void icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info)
 	icmp_param.data.icmph.un.gateway = info;
 	icmp_param.data.icmph.checksum	 = 0;
 	icmp_param.skb	  = skb_in;
-	icmp_param.offset = skb_in->nh.raw - skb_in->data;
+	icmp_param.offset = skb_network_offset(skb_in);
 	icmp_out_count(icmp_param.data.icmph.type);
 	inet_sk(icmp_socket->sk)->tos = tos;
 	ipc.addr = iph->saddr;
diff --git a/net/ipv4/ip_fragment.c b/net/ipv4/ip_fragment.c
index 3dfd758..268a6c7 100644
--- a/net/ipv4/ip_fragment.c
+++ b/net/ipv4/ip_fragment.c
@@ -658,7 +658,7 @@ static struct sk_buff *ip_frag_reasm(struct ipq *qp, struct net_device *dev)
 	}
 
 	skb_shinfo(head)->frag_list = head->next;
-	skb_push(head, head->data - head->nh.raw);
+	skb_push(head, head->data - skb_network_header(head));
 	atomic_sub(head->truesize, &ip_frag_mem);
 
 	for (fp=head->next; fp; fp = fp->next) {
diff --git a/net/ipv4/ip_options.c b/net/ipv4/ip_options.c
index f906a80..f7e9db6 100644
--- a/net/ipv4/ip_options.c
+++ b/net/ipv4/ip_options.c
@@ -40,7 +40,7 @@
 void ip_options_build(struct sk_buff * skb, struct ip_options * opt,
 			    __be32 daddr, struct rtable *rt, int is_frag)
 {
-	unsigned char * iph = skb->nh.raw;
+	unsigned char *iph = skb_network_header(skb);
 
 	memcpy(&(IPCB(skb)->opt), opt, sizeof(struct ip_options));
 	memcpy(iph+sizeof(struct iphdr), opt->__data, opt->optlen);
@@ -104,7 +104,7 @@ int ip_options_echo(struct ip_options * dopt, struct sk_buff * skb)
 		return 0;
 	}
 
-	sptr = skb->nh.raw;
+	sptr = skb_network_header(skb);
 	dptr = dopt->__data;
 
 	if (skb->dst)
@@ -217,7 +217,7 @@ int ip_options_echo(struct ip_options * dopt, struct sk_buff * skb)
 
 void ip_options_fragment(struct sk_buff * skb)
 {
-	unsigned char * optptr = skb->nh.raw + sizeof(struct iphdr);
+	unsigned char *optptr = skb_network_header(skb) + sizeof(struct iphdr);
 	struct ip_options * opt = &(IPCB(skb)->opt);
 	int  l = opt->optlen;
 	int  optlen;
@@ -264,7 +264,7 @@ int ip_options_compile(struct ip_options * opt, struct sk_buff * skb)
 
 	if (!opt) {
 		opt = &(IPCB(skb)->opt);
-		iph = skb->nh.raw;
+		iph = skb_network_header(skb);
 		opt->optlen = ((struct iphdr *)iph)->ihl*4 - sizeof(struct iphdr);
 		optptr = iph + sizeof(struct iphdr);
 		opt->is_data = 0;
@@ -563,7 +563,7 @@ void ip_forward_options(struct sk_buff *skb)
 	struct   ip_options * opt	= &(IPCB(skb)->opt);
 	unsigned char * optptr;
 	struct rtable *rt = (struct rtable*)skb->dst;
-	unsigned char *raw = skb->nh.raw;
+	unsigned char *raw = skb_network_header(skb);
 
 	if (opt->rr_needaddr) {
 		optptr = (unsigned char *)raw + opt->rr;
@@ -609,7 +609,7 @@ int ip_options_rcv_srr(struct sk_buff *skb)
 	int srrspace, srrptr;
 	__be32 nexthop;
 	struct iphdr *iph = skb->nh.iph;
-	unsigned char * optptr = skb->nh.raw + opt->srr;
+	unsigned char *optptr = skb_network_header(skb) + opt->srr;
 	struct rtable *rt = (struct rtable*)skb->dst;
 	struct rtable *rt2;
 	int err;
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index 669f5d9..eae2284 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -503,7 +503,7 @@ int ip_fragment(struct sk_buff *skb, int (*output)(struct sk_buff*))
 				frag->h.raw = frag->data;
 				__skb_push(frag, hlen);
 				skb_reset_network_header(frag);
-				memcpy(frag->nh.raw, iph, hlen);
+				memcpy(skb_network_header(frag), iph, hlen);
 				iph = frag->nh.iph;
 				iph->tot_len = htons(frag->len);
 				ip_copy_metadata(frag, skb);
@@ -607,7 +607,7 @@ slow_path:
 		 *	Copy the packet header into the new buffer.
 		 */
 
-		memcpy(skb2->nh.raw, skb->data, hlen);
+		memcpy(skb_network_header(skb2), skb->data, hlen);
 
 		/*
 		 *	Copy a block of the IP datagram.
@@ -1198,7 +1198,7 @@ int ip_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);
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index f8ab654..70888e1 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -273,7 +273,8 @@ void ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err,
 	serr->ee.ee_pad = 0;
 	serr->ee.ee_info = info;
 	serr->ee.ee_data = 0;
-	serr->addr_offset = (u8*)&(((struct iphdr*)(skb->h.icmph+1))->daddr) - skb->nh.raw;
+	serr->addr_offset = (u8 *)&(((struct iphdr *)(skb->h.icmph + 1))->daddr) -
+				   skb_network_header(skb);
 	serr->port = port;
 
 	skb->h.raw = payload;
@@ -309,7 +310,7 @@ void ip_local_error(struct sock *sk, int err, __be32 daddr, __be16 port, u32 inf
 	serr->ee.ee_pad = 0;
 	serr->ee.ee_info = info;
 	serr->ee.ee_data = 0;
-	serr->addr_offset = (u8*)&iph->daddr - skb->nh.raw;
+	serr->addr_offset = (u8 *)&iph->daddr - skb_network_header(skb);
 	serr->port = port;
 
 	skb->h.raw = skb->tail;
@@ -355,7 +356,8 @@ int ip_recv_error(struct sock *sk, struct msghdr *msg, int len)
 	sin = (struct sockaddr_in *)msg->msg_name;
 	if (sin) {
 		sin->sin_family = AF_INET;
-		sin->sin_addr.s_addr = *(__be32*)(skb->nh.raw + serr->addr_offset);
+		sin->sin_addr.s_addr = *(__be32 *)(skb_network_header(skb) +
+						   serr->addr_offset);
 		sin->sin_port = serr->port;
 		memset(&sin->sin_zero, 0, sizeof(sin->sin_zero));
 	}
diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index 51528d3..4a8d99b 100644
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -563,7 +563,7 @@ static int ipmr_cache_report(struct sk_buff *pkt, vifi_t vifi, int assert)
 		 */
 		msg = (struct igmpmsg*)skb_push(skb, sizeof(struct iphdr));
 		skb->nh.raw = skb->h.raw = (u8*)msg;
-		memcpy(msg, pkt->nh.raw, sizeof(struct iphdr));
+		memcpy(msg, skb_network_header(pkt), sizeof(struct iphdr));
 		msg->im_msgtype = IGMPMSG_WHOLEPKT;
 		msg->im_mbz = 0;
 		msg->im_vif = reg_vif_num;
diff --git a/net/ipv4/ipvs/ip_vs_app.c b/net/ipv4/ipvs/ip_vs_app.c
index 22e104c..f29d3a2 100644
--- a/net/ipv4/ipvs/ip_vs_app.c
+++ b/net/ipv4/ipvs/ip_vs_app.c
@@ -338,7 +338,7 @@ static inline int app_tcp_pkt_out(struct ip_vs_conn *cp, struct sk_buff **pskb,
 	if (!ip_vs_make_skb_writable(pskb, tcp_offset + sizeof(*th)))
 		return 0;
 
-	th = (struct tcphdr *)((*pskb)->nh.raw + tcp_offset);
+	th = (struct tcphdr *)(skb_network_header(*pskb) + tcp_offset);
 
 	/*
 	 *	Remember seq number in case this pkt gets resized
@@ -413,7 +413,7 @@ static inline int app_tcp_pkt_in(struct ip_vs_conn *cp, struct sk_buff **pskb,
 	if (!ip_vs_make_skb_writable(pskb, tcp_offset + sizeof(*th)))
 		return 0;
 
-	th = (struct tcphdr *)((*pskb)->nh.raw + tcp_offset);
+	th = (struct tcphdr *)(skb_network_header(*pskb) + tcp_offset);
 
 	/*
 	 *	Remember seq number in case this pkt gets resized
diff --git a/net/ipv4/ipvs/ip_vs_core.c b/net/ipv4/ipvs/ip_vs_core.c
index 858686d..5d54dd2 100644
--- a/net/ipv4/ipvs/ip_vs_core.c
+++ b/net/ipv4/ipvs/ip_vs_core.c
@@ -559,7 +559,8 @@ void ip_vs_nat_icmp(struct sk_buff *skb, struct ip_vs_protocol *pp,
 {
 	struct iphdr *iph	 = skb->nh.iph;
 	unsigned int icmp_offset = iph->ihl*4;
-	struct icmphdr *icmph	 = (struct icmphdr *)(skb->nh.raw + icmp_offset);
+	struct icmphdr *icmph	 = (struct icmphdr *)(skb_network_header(skb) +
+						      icmp_offset);
 	struct iphdr *ciph	 = (struct iphdr *)(icmph + 1);
 
 	if (inout) {
diff --git a/net/ipv4/netfilter/arpt_mangle.c b/net/ipv4/netfilter/arpt_mangle.c
index 709db4d..af1c859 100644
--- a/net/ipv4/netfilter/arpt_mangle.c
+++ b/net/ipv4/netfilter/arpt_mangle.c
@@ -31,7 +31,7 @@ target(struct sk_buff **pskb,
 	}
 
 	arp = (*pskb)->nh.arph;
-	arpptr = (*pskb)->nh.raw + sizeof(*arp);
+	arpptr = skb_network_header(*pskb) + sizeof(*arp);
 	pln = arp->ar_pln;
 	hln = arp->ar_hln;
 	/* We assume that pln and hln were checked in the match */
diff --git a/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c b/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c
index 8f3e92d..7cebbff 100644
--- a/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c
+++ b/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c
@@ -105,7 +105,7 @@ ipv4_prepare(struct sk_buff **pskb, unsigned int hooknum, unsigned int *dataoff,
 		return -NF_DROP;
 	}
 
-	*dataoff = (*pskb)->nh.raw - (*pskb)->data + (*pskb)->nh.iph->ihl*4;
+	*dataoff = skb_network_offset(*pskb) + (*pskb)->nh.iph->ihl * 4;
 	*protonum = (*pskb)->nh.iph->protocol;
 
 	return NF_ACCEPT;
@@ -151,10 +151,9 @@ static unsigned int ipv4_conntrack_help(unsigned int hooknum,
 	if (!help || !help->helper)
 		return NF_ACCEPT;
 
-	return help->helper->help(pskb,
-			       (*pskb)->nh.raw - (*pskb)->data
-					       + (*pskb)->nh.iph->ihl*4,
-			       ct, ctinfo);
+	return help->helper->help(pskb, (skb_network_offset(*pskb) +
+					 (*pskb)->nh.iph->ihl * 4),
+				  ct, ctinfo);
 }
 
 static unsigned int ipv4_conntrack_defrag(unsigned int hooknum,
diff --git a/net/ipv4/raw.c b/net/ipv4/raw.c
index 67e5e3c..a3d02fd 100644
--- a/net/ipv4/raw.c
+++ b/net/ipv4/raw.c
@@ -256,7 +256,7 @@ int raw_rcv(struct sock *sk, struct sk_buff *skb)
 	}
 	nf_reset(skb);
 
-	skb_push(skb, skb->data - skb->nh.raw);
+	skb_push(skb, skb->data - skb_network_header(skb));
 
 	raw_rcv_skb(sk, skb);
 	return 0;
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index f5e019c..0019083 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -3634,7 +3634,7 @@ tcp_collapse(struct sock *sk, struct sk_buff_head *list,
 			return;
 
 		skb_set_mac_header(nskb, skb_mac_header(skb) - skb->head);
-		nskb->nh.raw = nskb->data + (skb->nh.raw - skb->head);
+		nskb->nh.raw = nskb->data + (skb_network_header(skb) - skb->head);
 		nskb->h.raw = nskb->data + (skb->h.raw - skb->head);
 
 		skb_reserve(nskb, header);
diff --git a/net/ipv4/xfrm4_input.c b/net/ipv4/xfrm4_input.c
index 78e80de..d89969c 100644
--- a/net/ipv4/xfrm4_input.c
+++ b/net/ipv4/xfrm4_input.c
@@ -146,7 +146,7 @@ int xfrm4_rcv_encap(struct sk_buff *skb, __u16 encap_type)
 		return 0;
 	} else {
 #ifdef CONFIG_NETFILTER
-		__skb_push(skb, skb->data - skb->nh.raw);
+		__skb_push(skb, skb->data - skb_network_header(skb));
 		skb->nh.iph->tot_len = htons(skb->len);
 		ip_send_check(skb->nh.iph);
 
diff --git a/net/ipv4/xfrm4_mode_beet.c b/net/ipv4/xfrm4_mode_beet.c
index eaaf356..505fca0 100644
--- a/net/ipv4/xfrm4_mode_beet.c
+++ b/net/ipv4/xfrm4_mode_beet.c
@@ -98,7 +98,7 @@ static int xfrm4_beet_input(struct xfrm_state *x, struct sk_buff *skb)
 	}
 
 	skb->nh.raw = skb->data + (phlen - sizeof(*iph));
-	memmove(skb->nh.raw, iph, sizeof(*iph));
+	memmove(skb_network_header(skb), iph, sizeof(*iph));
 	skb->h.raw = skb->data + (phlen + optlen);
 	skb->data = skb->h.raw;
 
@@ -112,7 +112,7 @@ static int xfrm4_beet_input(struct xfrm_state *x, struct sk_buff *skb)
 	else
 		iph->protocol = protocol;
 	iph->check = 0;
-	iph->check = ip_fast_csum(skb->nh.raw, iph->ihl);
+	iph->check = ip_fast_csum(skb_network_header(skb), iph->ihl);
 	err = 0;
 out:
 	return err;
diff --git a/net/ipv4/xfrm4_mode_transport.c b/net/ipv4/xfrm4_mode_transport.c
index a820dde..b198087 100644
--- a/net/ipv4/xfrm4_mode_transport.c
+++ b/net/ipv4/xfrm4_mode_transport.c
@@ -34,7 +34,7 @@ static int xfrm4_transport_output(struct xfrm_state *x, struct sk_buff *skb)
 
 	skb_push(skb, x->props.header_len);
 	skb_reset_network_header(skb);
-	memmove(skb->nh.raw, iph, ihl);
+	memmove(skb_network_header(skb), iph, ihl);
 	return 0;
 }
 
@@ -51,7 +51,7 @@ static int xfrm4_transport_input(struct xfrm_state *x, struct sk_buff *skb)
 	int ihl = skb->data - skb->h.raw;
 
 	if (skb->h.raw != skb->nh.raw) {
-		memmove(skb->h.raw, skb->nh.raw, ihl);
+		memmove(skb->h.raw, skb_network_header(skb), ihl);
 		skb->nh.raw = skb->h.raw;
 	}
 	skb->nh.iph->tot_len = htons(skb->len + ihl);
diff --git a/net/ipv4/xfrm4_policy.c b/net/ipv4/xfrm4_policy.c
index 98a833c..fbb1d3d 100644
--- a/net/ipv4/xfrm4_policy.c
+++ b/net/ipv4/xfrm4_policy.c
@@ -210,7 +210,7 @@ static void
 _decode_session4(struct sk_buff *skb, struct flowi *fl)
 {
 	struct iphdr *iph = skb->nh.iph;
-	u8 *xprth = skb->nh.raw + iph->ihl*4;
+	u8 *xprth = skb_network_header(skb) + iph->ihl * 4;
 
 	memset(fl, 0, sizeof(struct flowi));
 	if (!(iph->frag_off & htons(IP_MF | IP_OFFSET))) {