[IPV6] MIP6: Add destination options header transformation.
Add destination options header transformation for Mobile IPv6.
Based on MIPL2 kernel patch.
This patch was also written by: Ville Nuorvala <vnuorval@tcs.hut.fi>
Signed-off-by: Noriaki TAKAMIYA <takamiya@po.ntts.co.jp>
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>
diff --git a/net/ipv6/mip6.c b/net/ipv6/mip6.c
index 63e548b..a8adf89 100644
--- a/net/ipv6/mip6.c
+++ b/net/ipv6/mip6.c
@@ -35,6 +35,165 @@
return x->coaddr;
}
+static inline unsigned int calc_padlen(unsigned int len, unsigned int n)
+{
+ return (n - len + 16) & 0x7;
+}
+
+static inline void *mip6_padn(__u8 *data, __u8 padlen)
+{
+ if (!data)
+ return NULL;
+ if (padlen == 1) {
+ data[0] = MIP6_OPT_PAD_1;
+ } else if (padlen > 1) {
+ data[0] = MIP6_OPT_PAD_N;
+ data[1] = padlen - 2;
+ if (padlen > 2)
+ memset(data+2, 0, data[1]);
+ }
+ return data + padlen;
+}
+
+static int mip6_destopt_input(struct xfrm_state *x, struct sk_buff *skb)
+{
+ struct ipv6hdr *iph = skb->nh.ipv6h;
+ struct ipv6_destopt_hdr *destopt = (struct ipv6_destopt_hdr *)skb->data;
+
+ if (!ipv6_addr_equal(&iph->saddr, (struct in6_addr *)x->coaddr) &&
+ !ipv6_addr_any((struct in6_addr *)x->coaddr))
+ return -ENOENT;
+
+ return destopt->nexthdr;
+}
+
+/* Destination Option Header is inserted.
+ * IP Header's src address is replaced with Home Address Option in
+ * Destination Option Header.
+ */
+static int mip6_destopt_output(struct xfrm_state *x, struct sk_buff *skb)
+{
+ struct ipv6hdr *iph;
+ struct ipv6_destopt_hdr *dstopt;
+ struct ipv6_destopt_hao *hao;
+ u8 nexthdr;
+ int len;
+
+ iph = (struct ipv6hdr *)skb->data;
+ iph->payload_len = htons(skb->len - sizeof(*iph));
+
+ nexthdr = *skb->nh.raw;
+ *skb->nh.raw = IPPROTO_DSTOPTS;
+
+ dstopt = (struct ipv6_destopt_hdr *)skb->h.raw;
+ dstopt->nexthdr = nexthdr;
+
+ hao = mip6_padn((char *)(dstopt + 1),
+ calc_padlen(sizeof(*dstopt), 6));
+
+ hao->type = IPV6_TLV_HAO;
+ hao->length = sizeof(*hao) - 2;
+ BUG_TRAP(hao->length == 16);
+
+ len = ((char *)hao - (char *)dstopt) + sizeof(*hao);
+
+ memcpy(&hao->addr, &iph->saddr, sizeof(hao->addr));
+ memcpy(&iph->saddr, x->coaddr, sizeof(iph->saddr));
+
+ BUG_TRAP(len == x->props.header_len);
+ dstopt->hdrlen = (x->props.header_len >> 3) - 1;
+
+ return 0;
+}
+
+static int mip6_destopt_offset(struct xfrm_state *x, struct sk_buff *skb,
+ u8 **nexthdr)
+{
+ u16 offset = sizeof(struct ipv6hdr);
+ struct ipv6_opt_hdr *exthdr = (struct ipv6_opt_hdr*)(skb->nh.ipv6h + 1);
+ unsigned int packet_len = skb->tail - skb->nh.raw;
+ int found_rhdr = 0;
+
+ *nexthdr = &skb->nh.ipv6h->nexthdr;
+
+ while (offset + 1 <= packet_len) {
+
+ switch (**nexthdr) {
+ case NEXTHDR_HOP:
+ break;
+ case NEXTHDR_ROUTING:
+ found_rhdr = 1;
+ break;
+ case NEXTHDR_DEST:
+ /*
+ * HAO MUST NOT appear more than once.
+ * XXX: It is better to try to find by the end of
+ * XXX: packet if HAO exists.
+ */
+ if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0) {
+ LIMIT_NETDEBUG(KERN_WARNING "mip6: hao exists already, override\n");
+ return offset;
+ }
+
+ if (found_rhdr)
+ return offset;
+
+ break;
+ default:
+ return offset;
+ }
+
+ offset += ipv6_optlen(exthdr);
+ *nexthdr = &exthdr->nexthdr;
+ exthdr = (struct ipv6_opt_hdr*)(skb->nh.raw + offset);
+ }
+
+ return offset;
+}
+
+static int mip6_destopt_init_state(struct xfrm_state *x)
+{
+ if (x->id.spi) {
+ printk(KERN_INFO "%s: spi is not 0: %u\n", __FUNCTION__,
+ x->id.spi);
+ return -EINVAL;
+ }
+ if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) {
+ printk(KERN_INFO "%s: state's mode is not %u: %u\n",
+ __FUNCTION__, XFRM_MODE_ROUTEOPTIMIZATION, x->props.mode);
+ return -EINVAL;
+ }
+
+ x->props.header_len = sizeof(struct ipv6_destopt_hdr) +
+ calc_padlen(sizeof(struct ipv6_destopt_hdr), 6) +
+ sizeof(struct ipv6_destopt_hao);
+ BUG_TRAP(x->props.header_len == 24);
+
+ return 0;
+}
+
+/*
+ * Do nothing about destroying since it has no specific operation for
+ * destination options header unlike IPsec protocols.
+ */
+static void mip6_destopt_destroy(struct xfrm_state *x)
+{
+}
+
+static struct xfrm_type mip6_destopt_type =
+{
+ .description = "MIP6DESTOPT",
+ .owner = THIS_MODULE,
+ .proto = IPPROTO_DSTOPTS,
+ .flags = XFRM_TYPE_NON_FRAGMENT,
+ .init_state = mip6_destopt_init_state,
+ .destructor = mip6_destopt_destroy,
+ .input = mip6_destopt_input,
+ .output = mip6_destopt_output,
+ .hdr_offset = mip6_destopt_offset,
+ .local_addr = mip6_xfrm_addr,
+};
+
static int mip6_rthdr_input(struct xfrm_state *x, struct sk_buff *skb)
{
struct rt2_hdr *rt2 = (struct rt2_hdr *)skb->data;
@@ -164,6 +323,10 @@
{
printk(KERN_INFO "Mobile IPv6\n");
+ if (xfrm_register_type(&mip6_destopt_type, AF_INET6) < 0) {
+ printk(KERN_INFO "%s: can't add xfrm type(destopt)\n", __FUNCTION__);
+ goto mip6_destopt_xfrm_fail;
+ }
if (xfrm_register_type(&mip6_rthdr_type, AF_INET6) < 0) {
printk(KERN_INFO "%s: can't add xfrm type(rthdr)\n", __FUNCTION__);
goto mip6_rthdr_xfrm_fail;
@@ -171,6 +334,8 @@
return 0;
mip6_rthdr_xfrm_fail:
+ xfrm_unregister_type(&mip6_destopt_type, AF_INET6);
+ mip6_destopt_xfrm_fail:
return -EAGAIN;
}
@@ -178,4 +343,6 @@
{
if (xfrm_unregister_type(&mip6_rthdr_type, AF_INET6) < 0)
printk(KERN_INFO "%s: can't remove xfrm type(rthdr)\n", __FUNCTION__);
+ if (xfrm_unregister_type(&mip6_destopt_type, AF_INET6) < 0)
+ printk(KERN_INFO "%s: can't remove xfrm type(destopt)\n", __FUNCTION__);
}