[IPV6] MIP6: Add inbound interface of home address option.

Add inbound function of home address option by registering it to TLV
table for destination options header.

Based on MIPL2 kernel patch.

This patch was also written by: Ville Nuorvala <vnuorval@tcs.hut.fi>

Signed-off-by: Masahide NAKAMURA <nakam@linux-ipv6.org>
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 86 insertions, 1 deletions

diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h
index 5bf4406e26d4..db3b2ba0f4f8 100644
--- a/include/linux/ipv6.h
+++ b/include/linux/ipv6.h
@@ -226,6 +226,9 @@ struct inet6_skb_parm {
         __u16                   dst0;
         __u16                   srcrt;
         __u16                   dst1;
+#ifdef CONFIG_IPV6_MIP6
+        __u16                   dsthao;
+#endif
         __u16                   lastopt;
         __u32                   nhoff;
         __u16                   flags;
diff --git a/net/ipv6/exthdrs.c b/net/ipv6/exthdrs.c
index 1cdd0f0b5d34..6a6466bb5f26 100644
--- a/net/ipv6/exthdrs.c
+++ b/net/ipv6/exthdrs.c
@@ -196,8 +196,80 @@ bad:
   Destination options header.
  *****************************/
 
+#ifdef CONFIG_IPV6_MIP6
+static int ipv6_dest_hao(struct sk_buff **skbp, int optoff)
+{
+        struct sk_buff *skb = *skbp;
+        struct ipv6_destopt_hao *hao;
+        struct inet6_skb_parm *opt = IP6CB(skb);
+        struct ipv6hdr *ipv6h = (struct ipv6hdr *)skb->nh.raw;
+        struct in6_addr tmp_addr;
+        int ret;
+
+        if (opt->dsthao) {
+                LIMIT_NETDEBUG(KERN_DEBUG "hao duplicated\n");
+                goto discard;
+        }
+        opt->dsthao = opt->dst1;
+        opt->dst1 = 0;
+
+        hao = (struct ipv6_destopt_hao *)(skb->nh.raw + optoff);
+
+        if (hao->length != 16) {
+                LIMIT_NETDEBUG(
+                        KERN_DEBUG "hao invalid option length = %d\n", hao->length);
+                goto discard;
+        }
+
+        if (!(ipv6_addr_type(&hao->addr) & IPV6_ADDR_UNICAST)) {
+                LIMIT_NETDEBUG(
+                        KERN_DEBUG "hao is not an unicast addr: " NIP6_FMT "\n", NIP6(hao->addr));
+                goto discard;
+        }
+
+        ret = xfrm6_input_addr(skb, (xfrm_address_t *)&ipv6h->daddr,
+                               (xfrm_address_t *)&hao->addr, IPPROTO_DSTOPTS);
+        if (unlikely(ret < 0))
+                goto discard;
+
+        if (skb_cloned(skb)) {
+                struct sk_buff *skb2 = skb_copy(skb, GFP_ATOMIC);
+                if (skb2 == NULL)
+                        goto discard;
+
+                kfree_skb(skb);
+
+                /* 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;
+        }
+
+        if (skb->ip_summed == CHECKSUM_COMPLETE)
+                skb->ip_summed = CHECKSUM_NONE;
+
+        ipv6_addr_copy(&tmp_addr, &ipv6h->saddr);
+        ipv6_addr_copy(&ipv6h->saddr, &hao->addr);
+        ipv6_addr_copy(&hao->addr, &tmp_addr);
+
+        if (skb->tstamp.off_sec == 0)
+                __net_timestamp(skb);
+
+        return 1;
+
+ discard:
+        kfree_skb(skb);
+        return 0;
+}
+#endif
+
 static struct tlvtype_proc tlvprocdestopt_lst[] = {
-        /* No destination options are defined now */
+#ifdef CONFIG_IPV6_MIP6
+        {
+                .type   = IPV6_TLV_HAO,
+                .func   = ipv6_dest_hao,
+        },
+#endif
         {-1,                    NULL}
 };
 
@@ -205,6 +277,9 @@ static int ipv6_destopt_rcv(struct sk_buff **skbp)
 {
         struct sk_buff *skb = *skbp;
         struct inet6_skb_parm *opt = IP6CB(skb);
+#ifdef CONFIG_IPV6_MIP6
+        __u16 dstbuf;
+#endif
 
         if (!pskb_may_pull(skb, (skb->h.raw-skb->data)+8) ||
             !pskb_may_pull(skb, (skb->h.raw-skb->data)+((skb->h.raw[1]+1)<<3))) {
@@ -215,11 +290,18 @@ static int ipv6_destopt_rcv(struct sk_buff **skbp)
 
         opt->lastopt = skb->h.raw - skb->nh.raw;
         opt->dst1 = skb->h.raw - skb->nh.raw;
+#ifdef CONFIG_IPV6_MIP6
+        dstbuf = opt->dst1;
+#endif
 
         if (ip6_parse_tlv(tlvprocdestopt_lst, skbp)) {
                 skb = *skbp;
                 skb->h.raw += ((skb->h.raw[1]+1)<<3);
+#ifdef CONFIG_IPV6_MIP6
+                opt->nhoff = dstbuf;
+#else
                 opt->nhoff = opt->dst1;
+#endif
                 return 1;
         }