[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 292516bb1eca..8f0df7b4dfe7 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 39216e6a59ed..e6a9e452fd61 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 602268661eb3..11029b9d4cf7 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 6b91c9f5d57a..4e19ee0e0102 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 05bc27002def..8f45c95db451 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 f832f3c33ab1..2b214cc3724c 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 c1ce36237380..9c3b4c7a50ad 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 32fcfc0b5c8c..591f0f1ef87f 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 2c46cbb3bbb5..dc8834ea3754 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);