[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>

drivers/isdn/i4l/isdn_net.c

@@ -872,7 +872,8 @@ typedef struct {
 static void
 isdn_net_log_skb(struct sk_buff * skb, isdn_net_local * lp)
 {
-	u_char *p = skb->nh.raw; /* hopefully, this was set correctly */
+	/* hopefully, this was set correctly */
+	const u_char *p = skb_network_header(skb);
 	unsigned short proto = ntohs(skb->protocol);
 	int data_ofs;
 	ip_ports *ipp;
@@ -880,7 +881,7 @@ isdn_net_log_skb(struct sk_buff * skb, isdn_net_local * lp)
 
 	addinfo[0] = '\0';
 	/* This check stolen from 2.1.72 dev_queue_xmit_nit() */
-	if (skb->nh.raw < skb->data || skb->nh.raw >= skb->tail) {
+	if (p < skb->data || p >= skb->tail) {
 		/* fall back to old isdn_net_log_packet method() */
 		char * buf = skb->data;
 

drivers/net/bonding/bond_alb.c

@@ -106,7 +106,7 @@ struct arp_pkt {
 
 static inline struct arp_pkt *arp_pkt(const struct sk_buff *skb)
 {
-	return (struct arp_pkt *)skb->nh.raw;
+	return (struct arp_pkt *)skb_network_header(skb);
 }
 
 /* Forward declaration */

drivers/net/loopback.c

@@ -76,7 +76,8 @@ static DEFINE_PER_CPU(struct pcpu_lstats, pcpu_lstats);
 static void emulate_large_send_offload(struct sk_buff *skb)
 {
 	struct iphdr *iph = skb->nh.iph;
-	struct tcphdr *th = (struct tcphdr*)(skb->nh.raw + (iph->ihl * 4));
+	struct tcphdr *th = (struct tcphdr *)(skb_network_header(skb) +
+					      (iph->ihl * 4));
 	unsigned int doffset = (iph->ihl + th->doff) * 4;
 	unsigned int mtu = skb_shinfo(skb)->gso_size + doffset;
 	unsigned int offset = 0;
@@ -93,7 +94,7 @@ static void emulate_large_send_offload(struct sk_buff *skb)
 		skb_set_mac_header(nskb, -ETH_HLEN);
 		skb_reset_network_header(nskb);
 		iph = nskb->nh.iph;
-		memcpy(nskb->data, skb->nh.raw, doffset);
+		memcpy(nskb->data, skb_network_header(skb), doffset);
 		if (skb_copy_bits(skb,
 				  doffset + offset,
 				  nskb->data + doffset,
@@ -108,7 +109,7 @@ static void emulate_large_send_offload(struct sk_buff *skb)
 		memcpy(nskb->cb, skb->cb, sizeof(skb->cb));
 		nskb->pkt_type = skb->pkt_type;
 
-		th = (struct tcphdr*)(nskb->nh.raw + iph->ihl*4);
+		th = (struct tcphdr *)(skb_network_header(nskb) + iph->ihl * 4);
 		iph->tot_len = htons(frag_size + doffset);
 		iph->id = htons(id);
 		iph->check = 0;

drivers/net/pasemi_mac.c

@@ -729,16 +729,18 @@ static int pasemi_mac_start_tx(struct sk_buff *skb, struct net_device *dev)
 	dflags = XCT_MACTX_O | XCT_MACTX_ST | XCT_MACTX_SS | XCT_MACTX_CRC_PAD;
 
 	if (skb->ip_summed == CHECKSUM_PARTIAL) {
+		const unsigned char *nh = skb_network_header(skb);
+
 		switch (skb->nh.iph->protocol) {
 		case IPPROTO_TCP:
 			dflags |= XCT_MACTX_CSUM_TCP;
 			dflags |= XCT_MACTX_IPH((skb->h.raw - skb->nh.raw) >> 2);
-			dflags |= XCT_MACTX_IPO(skb->nh.raw - skb->data);
+			dflags |= XCT_MACTX_IPO(nh - skb->data);
 			break;
 		case IPPROTO_UDP:
 			dflags |= XCT_MACTX_CSUM_UDP;
 			dflags |= XCT_MACTX_IPH((skb->h.raw - skb->nh.raw) >> 2);
-			dflags |= XCT_MACTX_IPO(skb->nh.raw - skb->data);
+			dflags |= XCT_MACTX_IPO(nh - skb->data);
 			break;
 		}
 	}

drivers/s390/net/qeth_main.c

@@ -3778,9 +3778,11 @@ qeth_get_cast_type(struct qeth_card *card, struct sk_buff *skb)
 	}
 	/* try something else */
 	if (skb->protocol == ETH_P_IPV6)
-		return (skb->nh.raw[24] == 0xff) ? RTN_MULTICAST : 0;
+		return (skb_network_header(skb)[24] == 0xff) ?
+				RTN_MULTICAST : 0;
 	else if (skb->protocol == ETH_P_IP)
-		return ((skb->nh.raw[16] & 0xf0) == 0xe0) ? RTN_MULTICAST : 0;
+		return ((skb_network_header(skb)[16] & 0xf0) == 0xe0) ?
+				RTN_MULTICAST : 0;
 	/* ... */
 	if (!memcmp(skb->data, skb->dev->broadcast, 6))
 		return RTN_BROADCAST;

include/linux/if_pppox.h

@@ -116,7 +116,7 @@ struct pppoe_hdr {
 
 static inline struct pppoe_hdr *pppoe_hdr(const struct sk_buff *skb)
 {
-	return (struct pppoe_hdr *)skb->nh.raw;
+	return (struct pppoe_hdr *)skb_network_header(skb);
 }
 
 struct pppoe_opt {

include/linux/skbuff.h

@@ -960,6 +960,11 @@ static inline void skb_reserve(struct sk_buff *skb, int len)
 	skb->tail += len;
 }
 
+static inline unsigned char *skb_network_header(const struct sk_buff *skb)
+{
+	return skb->nh.raw;
+}
+
 static inline void skb_reset_network_header(struct sk_buff *skb)
 {
 	skb->nh.raw = skb->data;

include/net/cipso_ipv4.h

@@ -120,7 +120,7 @@ extern int cipso_v4_rbm_strictvalid;
  */
 
 #define CIPSO_V4_OPTEXIST(x) (IPCB(x)->opt.cipso != 0)
-#define CIPSO_V4_OPTPTR(x) ((x)->nh.raw + IPCB(x)->opt.cipso)
+#define CIPSO_V4_OPTPTR(x) (skb_network_header(x) + IPCB(x)->opt.cipso)
 
 /*
  * DOI List Functions

include/net/inet_ecn.h

@@ -114,12 +114,14 @@ static inline int INET_ECN_set_ce(struct sk_buff *skb)
 {
 	switch (skb->protocol) {
 	case __constant_htons(ETH_P_IP):
-		if (skb->nh.raw + sizeof(struct iphdr) <= skb->tail)
+		if (skb_network_header(skb) + sizeof(struct iphdr) <=
+		    skb->tail)
 			return IP_ECN_set_ce(skb->nh.iph);
 		break;
 
 	case __constant_htons(ETH_P_IPV6):
-		if (skb->nh.raw + sizeof(struct ipv6hdr) <= skb->tail)
+		if (skb_network_header(skb) + sizeof(struct ipv6hdr) <=
+		    skb->tail)
 			return IP6_ECN_set_ce(skb->nh.ipv6h);
 		break;
 	}

include/net/llc_pdu.h

@@ -203,7 +203,7 @@ struct llc_pdu_sn {
 
 static inline struct llc_pdu_sn *llc_pdu_sn_hdr(struct sk_buff *skb)
 {
-	return (struct llc_pdu_sn *)skb->nh.raw;
+	return (struct llc_pdu_sn *)skb_network_header(skb);
 }
 
 /* Un-numbered PDU format (3 bytes in length) */
@@ -215,7 +215,7 @@ struct llc_pdu_un {
 
 static inline struct llc_pdu_un *llc_pdu_un_hdr(struct sk_buff *skb)
 {
-	return (struct llc_pdu_un *)skb->nh.raw;
+	return (struct llc_pdu_un *)skb_network_header(skb);
 }
 
 /**

include/net/pkt_cls.h

@@ -326,7 +326,7 @@ static inline unsigned char * tcf_get_base_ptr(struct sk_buff *skb, int layer)
 		case TCF_LAYER_LINK:
 			return skb->data;
 		case TCF_LAYER_NETWORK:
-			return skb->nh.raw;
+			return skb_network_header(skb);
 		case TCF_LAYER_TRANSPORT:
 			return skb->h.raw;
 	}

net/bridge/br_netfilter.c

@@ -374,7 +374,8 @@ static int check_hbh_len(struct sk_buff *skb)
 {
 	unsigned char *raw = (u8 *) (skb->nh.ipv6h + 1);
 	u32 pkt_len;
-	int off = raw - skb->nh.raw;
+	const unsigned char *nh = skb_network_header(skb);
+	int off = raw - nh;
 	int len = (raw[1] + 1) << 3;
 
 	if ((raw + len) - skb->data > skb_headlen(skb))
@@ -384,9 +385,9 @@ static int check_hbh_len(struct sk_buff *skb)
 	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;
@@ -395,9 +396,9 @@ static int check_hbh_len(struct sk_buff *skb)
 			break;
 
 		case IPV6_TLV_JUMBO:
-			if (skb->nh.raw[off + 1] != 4 || (off & 3) != 2)
+			if (nh[off + 1] != 4 || (off & 3) != 2)
 				goto bad;
-			pkt_len = ntohl(*(__be32 *) (skb->nh.raw + off + 2));
+			pkt_len = ntohl(*(__be32 *) (nh + off + 2));
 			if (pkt_len <= IPV6_MAXPLEN ||
 			    skb->nh.ipv6h->payload_len)
 				goto bad;
@@ -406,6 +407,7 @@ static int check_hbh_len(struct sk_buff *skb)
 			if (pskb_trim_rcsum(skb,
 					    pkt_len + sizeof(struct ipv6hdr)))
 				goto bad;
+			nh = skb_network_header(skb);
 			break;
 		default:
 			if (optlen > len)

net/core/dev.c

@@ -1068,8 +1068,8 @@ static void dev_queue_xmit_nit(struct sk_buff *skb, struct net_device *dev)
 			 */
 			skb_reset_mac_header(skb2);
 
-			if (skb2->nh.raw < skb2->data ||
-			    skb2->nh.raw > skb2->tail) {
+			if (skb_network_header(skb2) < skb2->data ||
+			    skb_network_header(skb2) > skb2->tail) {
 				if (net_ratelimit())
 					printk(KERN_CRIT "protocol %04x is "
 					       "buggy, dev %s\n",
@@ -1207,7 +1207,7 @@ struct sk_buff *skb_gso_segment(struct sk_buff *skb, int features)
 	BUG_ON(skb_shinfo(skb)->frag_list);
 
 	skb_reset_mac_header(skb);
-	skb->mac_len = skb->nh.raw - skb->data;
+	skb->mac_len = skb->nh.raw - skb->mac.raw;
 	__skb_pull(skb, skb->mac_len);
 
 	if (unlikely(skb->ip_summed != CHECKSUM_PARTIAL)) {
@@ -1224,7 +1224,8 @@ struct sk_buff *skb_gso_segment(struct sk_buff *skb, int features)
 				segs = ERR_PTR(err);
 				if (err || skb_gso_ok(skb, features))
 					break;
-				__skb_push(skb, skb->data - skb->nh.raw);
+				__skb_push(skb, (skb->data -
+						 skb_network_header(skb)));
 			}
 			segs = ptype->gso_segment(skb, features);
 			break;

net/core/filter.c

@@ -42,7 +42,7 @@ static void *__load_pointer(struct sk_buff *skb, int k)
 	u8 *ptr = NULL;
 
 	if (k >= SKF_NET_OFF)
-		ptr = skb->nh.raw + k - SKF_NET_OFF;
+		ptr = skb_network_header(skb) + k - SKF_NET_OFF;
 	else if (k >= SKF_LL_OFF)
 		ptr = skb_mac_header(skb) + k - SKF_LL_OFF;
 

net/dccp/ipv6.c

@@ -261,8 +261,8 @@ static int dccp_v6_send_response(struct sock *sk, struct request_sock *req,
 
 			if (rxopt->srcrt)
 				opt = ipv6_invert_rthdr(sk,
-					(struct ipv6_rt_hdr *)(pktopts->nh.raw +
-							       rxopt->srcrt));
+			  (struct ipv6_rt_hdr *)(skb_network_header(pktopts) +
+						 rxopt->srcrt));
 		}
 
 		if (opt != NULL && opt->srcrt != NULL) {
@@ -573,8 +573,8 @@ static struct sock *dccp_v6_request_recv_sock(struct sock *sk,
 
 		if (rxopt->srcrt)
 			opt = ipv6_invert_rthdr(sk,
-				(struct ipv6_rt_hdr *)(ireq6->pktopts->nh.raw +
-						       rxopt->srcrt));
+		   (struct ipv6_rt_hdr *)(skb_network_header(ireq6->pktopts) +
+					  rxopt->srcrt));
 	}
 
 	if (dst == NULL) {

net/decnet/dn_route.c

@@ -386,7 +386,7 @@ static int dn_return_short(struct sk_buff *skb)
 	__le16 tmp;
 
 	/* Add back headers */
-	skb_push(skb, skb->data - skb->nh.raw);
+	skb_push(skb, skb->data - skb_network_header(skb));
 
 	if ((skb = skb_unshare(skb, GFP_ATOMIC)) == NULL)
 		return NET_RX_DROP;
@@ -425,7 +425,7 @@ static int dn_return_long(struct sk_buff *skb)
 	unsigned char tmp[ETH_ALEN];
 
 	/* Add back all headers */
-	skb_push(skb, skb->data - skb->nh.raw);
+	skb_push(skb, skb->data - skb_network_header(skb));
 
 	if ((skb = skb_unshare(skb, GFP_ATOMIC)) == NULL)
 		return NET_RX_DROP;

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:

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;

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

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;