[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>

1 files changed, 33 insertions, 23 deletions

diff --git a/net/ipv6/exthdrs.c b/net/ipv6/exthdrs.c
index fce5abde554f..9ebf120ba6d3 100644
--- a/net/ipv6/exthdrs.c
+++ b/net/ipv6/exthdrs.c
@@ -50,13 +50,14 @@
 
 int ipv6_find_tlv(struct sk_buff *skb, int offset, int type)
 {
-        int packet_len = skb->tail - skb->nh.raw;
+        const unsigned char *nh = skb_network_header(skb);
+        int packet_len = skb->tail - nh;
         struct ipv6_opt_hdr *hdr;
         int len;
 
         if (offset + 2 > packet_len)
                 goto bad;
-        hdr = (struct ipv6_opt_hdr*)(skb->nh.raw + offset);
+        hdr = (struct ipv6_opt_hdr *)(nh + offset);
         len = ((hdr->hdrlen + 1) << 3);
 
         if (offset + len > packet_len)
@@ -66,7 +67,7 @@ int ipv6_find_tlv(struct sk_buff *skb, int offset, int type)
         len -= 2;
 
         while (len > 0) {
-                int opttype = skb->nh.raw[offset];
+                int opttype = nh[offset];
                 int optlen;
 
                 if (opttype == type)
@@ -77,7 +78,7 @@ int ipv6_find_tlv(struct sk_buff *skb, int offset, int type)
                         optlen = 1;
                         break;
                 default:
-                        optlen = skb->nh.raw[offset + 1] + 2;
+                        optlen = nh[offset + 1] + 2;
                         if (optlen > len)
                                 goto bad;
                         break;
@@ -113,7 +114,7 @@ static int ip6_tlvopt_unknown(struct sk_buff **skbp, int optoff)
 {
         struct sk_buff *skb = *skbp;
 
-        switch ((skb->nh.raw[optoff] & 0xC0) >> 6) {
+        switch ((skb_network_header(skb)[optoff] & 0xC0) >> 6) {
         case 0: /* ignore */
                 return 1;
 
@@ -141,6 +142,7 @@ 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 len = ((skb->h.raw[1]+1)<<3);
 
@@ -151,9 +153,9 @@ static int ip6_parse_tlv(struct tlvtype_proc *procs, struct sk_buff **skbp)
         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;
@@ -165,7 +167,7 @@ static int ip6_parse_tlv(struct tlvtype_proc *procs, struct sk_buff **skbp)
                         if (optlen > len)
                                 goto bad;
                         for (curr=procs; curr->type >= 0; curr++) {
-                                if (curr->type == skb->nh.raw[off]) {
+                                if (curr->type == nh[off]) {
                                         /* type specific length/alignment
                                            checks will be performed in the
                                            func(). */
@@ -211,7 +213,7 @@ static int ipv6_dest_hao(struct sk_buff **skbp, int optoff)
         opt->dsthao = opt->dst1;
         opt->dst1 = 0;
 
-        hao = (struct ipv6_destopt_hao *)(skb->nh.raw + optoff);
+        hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) + optoff);
 
         if (hao->length != 16) {
                 LIMIT_NETDEBUG(
@@ -244,8 +246,9 @@ static int ipv6_dest_hao(struct sk_buff **skbp, int optoff)
 
                 /* update all variable using below by copied skbuff */
                 *skbp = skb = skb2;
-                hao = (struct ipv6_destopt_hao *)(skb2->nh.raw + optoff);
-                ipv6h = (struct ipv6hdr *)skb2->nh.raw;
+                hao = (struct ipv6_destopt_hao *)(skb_network_header(skb2) +
+                                                  optoff);
+                ipv6h = skb2->nh.ipv6h;
         }
 
         if (skb->ip_summed == CHECKSUM_COMPLETE)
@@ -406,7 +409,8 @@ static int ipv6_rthdr_rcv(struct sk_buff **skbp)
         default:
                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
                                  IPSTATS_MIB_INHDRERRORS);
-                icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, (&hdr->type) - skb->nh.raw);
+                icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
+                                  (&hdr->type) - skb_network_header(skb));
                 return -1;
         }
 
@@ -443,7 +447,7 @@ looped_back:
                 skb->h.raw += (hdr->hdrlen + 1) << 3;
                 opt->dst0 = opt->dst1;
                 opt->dst1 = 0;
-                opt->nhoff = (&hdr->nexthdr) - skb->nh.raw;
+                opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
                 return 1;
         }
 
@@ -452,7 +456,9 @@ looped_back:
                 if (hdr->hdrlen & 0x01) {
                         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
                                          IPSTATS_MIB_INHDRERRORS);
-                        icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, (&hdr->hdrlen) - skb->nh.raw);
+                        icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
+                                          ((&hdr->hdrlen) -
+                                           skb_network_header(skb)));
                         return -1;
                 }
                 break;
@@ -479,7 +485,9 @@ looped_back:
         if (hdr->segments_left > n) {
                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
                                  IPSTATS_MIB_INHDRERRORS);
-                icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, (&hdr->segments_left) - skb->nh.raw);
+                icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
+                                  ((&hdr->segments_left) -
+                                   skb_network_header(skb)));
                 return -1;
         }
 
@@ -547,7 +555,7 @@ looped_back:
         dst_release(xchg(&skb->dst, NULL));
         ip6_route_input(skb);
         if (skb->dst->error) {
-                skb_push(skb, skb->data - skb->nh.raw);
+                skb_push(skb, skb->data - skb_network_header(skb));
                 dst_input(skb);
                 return -1;
         }
@@ -565,7 +573,7 @@ looped_back:
                 goto looped_back;
         }
 
-        skb_push(skb, skb->data - skb->nh.raw);
+        skb_push(skb, skb->data - skb_network_header(skb));
         dst_input(skb);
         return -1;
 }
@@ -656,13 +664,14 @@ EXPORT_SYMBOL_GPL(ipv6_invert_rthdr);
 static int ipv6_hop_ra(struct sk_buff **skbp, int optoff)
 {
         struct sk_buff *skb = *skbp;
+        const unsigned char *nh = skb_network_header(skb);
 
-        if (skb->nh.raw[optoff+1] == 2) {
+        if (nh[optoff + 1] == 2) {
                 IP6CB(skb)->ra = optoff;
                 return 1;
         }
         LIMIT_NETDEBUG(KERN_DEBUG "ipv6_hop_ra: wrong RA length %d\n",
-                       skb->nh.raw[optoff+1]);
+                       nh[optoff + 1]);
         kfree_skb(skb);
         return 0;
 }
@@ -672,17 +681,18 @@ static int ipv6_hop_ra(struct sk_buff **skbp, int optoff)
 static int ipv6_hop_jumbo(struct sk_buff **skbp, int optoff)
 {
         struct sk_buff *skb = *skbp;
+        const unsigned char *nh = skb_network_header(skb);
         u32 pkt_len;
 
-        if (skb->nh.raw[optoff+1] != 4 || (optoff&3) != 2) {
+        if (nh[optoff + 1] != 4 || (optoff & 3) != 2) {
                 LIMIT_NETDEBUG(KERN_DEBUG "ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n",
-                               skb->nh.raw[optoff+1]);
+                               nh[optoff+1]);
                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
                                  IPSTATS_MIB_INHDRERRORS);
                 goto drop;
         }
 
-        pkt_len = ntohl(*(__be32*)(skb->nh.raw+optoff+2));
+        pkt_len = ntohl(*(__be32 *)(nh + optoff + 2));
         if (pkt_len <= IPV6_MAXPLEN) {
                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_INHDRERRORS);
                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff+2);
@@ -727,7 +737,7 @@ int ipv6_parse_hopopts(struct sk_buff **skbp)
         struct inet6_skb_parm *opt = IP6CB(skb);
 
         /*
-         * skb->nh.raw is equal to skb->data, and
+         * skb_network_header(skb) is equal to skb->data, and
          * skb->h.raw - skb->nh.raw is always equal to
          * sizeof(struct ipv6hdr) by definition of
          * hop-by-hop options.