[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 6e5575b0abef..ab552a6098f9 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 7194eb40b6d0..95ddbbd1552a 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 31041127eeb8..222d21e5bbeb 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 4b7a0d946a0d..ff124d40c585 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 3dfd7581cfc6..268a6c7347f2 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 f906a80d5a87..f7e9db612565 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 669f5d97c6eb..eae228469627 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 f8ab654b6a35..70888e1ef6b7 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 51528d3cc334..4a8d99bca441 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 22e104c6a493..f29d3a27eec6 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 858686d616a2..5d54dd2ce12f 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 709db4d3f48f..af1c8593eb19 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 8f3e92d20df8..7cebbff0b0c3 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 67e5e3c035c1..a3d02fdfc066 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 f5e019cefc15..00190835cea1 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 78e80deb7e89..d89969c502dd 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 eaaf3565f3b2..505fca034a1f 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 a820dde2c862..b198087c073e 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 98a833ce1114..fbb1d3decf02 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))) {