[SK_BUFF]: Introduce skb_network_header_len

For the common sequence "skb->h.raw - skb->nh.raw", similar to skb->mac_len,
that is precalculated tho, don't think we need to bloat skb with one more
member, so just use this new helper, reducing the number of non-skbuff.h
references to the layer headers even more.

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

drivers/net/gianfar.c

@@ -953,7 +953,7 @@ static inline void gfar_tx_checksum(struct sk_buff *skb, struct txfcb *fcb)
 	 * l4os is the distance between the start of the
 	 * l3 hdr and the l4 hdr */
 	fcb->l3os = (u16)(skb_network_offset(skb) - GMAC_FCB_LEN);
-	fcb->l4os = (u16)(skb->h.raw - skb->nh.raw);
+	fcb->l4os = skb_network_header_len(skb);
 
 	fcb->flags = flags;
 }

drivers/net/pasemi_mac.c

@@ -734,12 +734,12 @@ static int pasemi_mac_start_tx(struct sk_buff *skb, struct net_device *dev)
 		switch (ip_hdr(skb)->protocol) {
 		case IPPROTO_TCP:
 			dflags |= XCT_MACTX_CSUM_TCP;
-			dflags |= XCT_MACTX_IPH((skb->h.raw - skb->nh.raw) >> 2);
+			dflags |= XCT_MACTX_IPH(skb_network_header_len(skb) >> 2);
 			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_IPH(skb_network_header_len(skb) >> 2);
 			dflags |= XCT_MACTX_IPO(nh - skb->data);
 			break;
 		}

include/linux/skbuff.h

@@ -992,6 +992,11 @@ static inline int skb_network_offset(const struct sk_buff *skb)
 	return skb->nh.raw - skb->data;
 }
 
+static inline u32 skb_network_header_len(const struct sk_buff *skb)
+{
+	return skb->h.raw - skb->nh.raw;
+}
+
 static inline unsigned char *skb_mac_header(const struct sk_buff *skb)
 {
 	return skb->mac.raw;

net/core/skbuff.c

@@ -1906,7 +1906,7 @@ struct sk_buff *skb_segment(struct sk_buff *skb, int features)
 		skb_reserve(nskb, headroom);
 		skb_reset_mac_header(nskb);
 		skb_set_network_header(nskb, skb->mac_len);
-		nskb->h.raw = nskb->nh.raw + (skb->h.raw - skb->nh.raw);
+		nskb->h.raw = nskb->nh.raw + skb_network_header_len(skb);
 		memcpy(skb_put(nskb, doffset), skb->data, doffset);
 
 		if (!sg) {

net/ipv4/ip_output.c

@@ -1187,7 +1187,7 @@ int ip_push_pending_frames(struct sock *sk)
 	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);
+		__skb_pull(tmp_skb, skb_network_header_len(skb));
 		*tail_skb = tmp_skb;
 		tail_skb = &(tmp_skb->next);
 		skb->len += tmp_skb->len;

net/ipv6/esp6.c

@@ -147,8 +147,7 @@ static int esp6_input(struct xfrm_state *x, struct sk_buff *skb)
 	int blksize = ALIGN(crypto_blkcipher_blocksize(tfm), 4);
 	int alen = esp->auth.icv_trunc_len;
 	int elen = skb->len - sizeof(struct ipv6_esp_hdr) - esp->conf.ivlen - alen;
-
-	int hdr_len = skb->h.raw - skb->nh.raw;
+	int hdr_len = skb_network_header_len(skb);
 	int nfrags;
 	int ret = 0;
 

net/ipv6/exthdrs.c

@@ -143,7 +143,7 @@ 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 off = skb_network_header_len(skb);
 	int len = (skb_transport_header(skb)[1] + 1) << 3;
 
 	if (skb_transport_offset(skb) + len > skb_headlen(skb))
@@ -297,7 +297,7 @@ static int ipv6_destopt_rcv(struct sk_buff **skbp)
 		return -1;
 	}
 
-	opt->lastopt = opt->dst1 = skb->h.raw - skb->nh.raw;
+	opt->lastopt = opt->dst1 = skb_network_header_len(skb);
 #ifdef CONFIG_IPV6_MIP6
 	dstbuf = opt->dst1;
 #endif
@@ -443,7 +443,7 @@ static int ipv6_rthdr_rcv(struct sk_buff **skbp)
 			break;
 		}
 
-		opt->lastopt = opt->srcrt = skb->h.raw - skb->nh.raw;
+		opt->lastopt = opt->srcrt = skb_network_header_len(skb);
 		skb->h.raw += (hdr->hdrlen + 1) << 3;
 		opt->dst0 = opt->dst1;
 		opt->dst1 = 0;
@@ -738,7 +738,7 @@ int ipv6_parse_hopopts(struct sk_buff **skbp)
 
 	/*
 	 * skb_network_header(skb) is equal to skb->data, and
-	 * skb->h.raw - skb->nh.raw is always equal to
+	 * skb_network_header_len(skb) is always equal to
 	 * sizeof(struct ipv6hdr) by definition of
 	 * hop-by-hop options.
 	 */

net/ipv6/ip6_input.c

@@ -182,7 +182,7 @@ static inline int ip6_input_finish(struct sk_buff *skb)
 			nf_reset(skb);
 
 			skb_postpull_rcsum(skb, skb_network_header(skb),
-					   skb->h.raw - skb->nh.raw);
+					   skb_network_header_len(skb));
 			hdr = ipv6_hdr(skb);
 			if (ipv6_addr_is_multicast(&hdr->daddr) &&
 			    !ipv6_chk_mcast_addr(skb->dev, &hdr->daddr,

net/ipv6/ip6_output.c

@@ -1325,7 +1325,7 @@ int ip6_push_pending_frames(struct sock *sk)
 	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);
+		__skb_pull(tmp_skb, skb_network_header_len(skb));
 		*tail_skb = tmp_skb;
 		tail_skb = &(tmp_skb->next);
 		skb->len += tmp_skb->len;
@@ -1337,7 +1337,7 @@ int ip6_push_pending_frames(struct sock *sk)
 	}
 
 	ipv6_addr_copy(final_dst, &fl->fl6_dst);
-	__skb_pull(skb, skb->h.raw - skb->nh.raw);
+	__skb_pull(skb, skb_network_header_len(skb));
 	if (opt && opt->opt_flen)
 		ipv6_push_frag_opts(skb, opt, &proto);
 	if (opt && opt->opt_nflen)

net/ipv6/mcast.c

@@ -1168,7 +1168,7 @@ int igmp6_event_query(struct sk_buff *skb)
 
 	/* compute payload length excluding extension headers */
 	len = ntohs(ipv6_hdr(skb)->payload_len) + sizeof(struct ipv6hdr);
-	len -= skb->h.raw - skb->nh.raw;
+	len -= skb_network_header_len(skb);
 
 	/* Drop queries with not link local source */
 	if (!(ipv6_addr_type(&ipv6_hdr(skb)->saddr) & IPV6_ADDR_LINKLOCAL))

net/ipv6/netfilter/nf_conntrack_reasm.c

@@ -657,7 +657,7 @@ nf_ct_frag6_reasm(struct nf_ct_frag6_queue *fq, struct net_device *dev)
 	/* Yes, and fold redundant checksum back. 8) */
 	if (head->ip_summed == CHECKSUM_COMPLETE)
 		head->csum = csum_partial(skb_network_header(head),
-					  head->h.raw - head->nh.raw,
+					  skb_network_header_len(head),
 					  head->csum);
 
 	fq->fragments = NULL;

net/ipv6/raw.c

@@ -362,7 +362,7 @@ int rawv6_rcv(struct sock *sk, struct sk_buff *skb)
 
 	if (skb->ip_summed == CHECKSUM_COMPLETE) {
 		skb_postpull_rcsum(skb, skb_network_header(skb),
-				   skb->h.raw - skb->nh.raw);
+				   skb_network_header_len(skb));
 		if (!csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
 				     &ipv6_hdr(skb)->daddr,
 				     skb->len, inet->num, skb->csum))

net/ipv6/reassembly.c

@@ -679,7 +679,7 @@ static int ip6_frag_reasm(struct frag_queue *fq, struct sk_buff **skb_in,
 	/* Yes, and fold redundant checksum back. 8) */
 	if (head->ip_summed == CHECKSUM_COMPLETE)
 		head->csum = csum_partial(skb_network_header(head),
-					  head->h.raw - head->nh.raw,
+					  skb_network_header_len(head),
 					  head->csum);
 
 	rcu_read_lock();
@@ -715,13 +715,15 @@ static int ipv6_frag_rcv(struct sk_buff **skbp)
 	/* Jumbo payload inhibits frag. header */
 	if (hdr->payload_len==0) {
 		IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_INHDRERRORS);
-		icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, skb->h.raw-skb->nh.raw);
+		icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
+				  skb_network_header_len(skb));
 		return -1;
 	}
 	if (!pskb_may_pull(skb, (skb_transport_offset(skb) +
 				 sizeof(struct frag_hdr)))) {
 		IP6_INC_STATS(ip6_dst_idev(skb->dst), IPSTATS_MIB_INHDRERRORS);
-		icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, skb->h.raw-skb->nh.raw);
+		icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
+				  skb_network_header_len(skb));
 		return -1;
 	}
 

net/ipv6/xfrm6_policy.c

@@ -270,7 +270,7 @@ __xfrm6_bundle_create(struct xfrm_policy *policy, struct xfrm_state **xfrm, int
 static inline void
 _decode_session6(struct sk_buff *skb, struct flowi *fl)
 {
-	u16 offset = skb->h.raw - skb->nh.raw;
+	u16 offset = skb_network_header_len(skb);
 	struct ipv6hdr *hdr = ipv6_hdr(skb);
 	struct ipv6_opt_hdr *exthdr;
 	const unsigned char *nh = skb_network_header(skb);