From: Fred L. Templin <[EMAIL PROTECTED]>
This is experimental support for the Intra-Site Automatic
Tunnel Addressing Protocol (ISATAP) per RFC4214. It uses
the SIT module, and is configured using the unmodified
"ip" utility with device names beginning with: "isatap".
The following diffs are specific to the Linux 2.6.23
kernel distribution.
Signed-off-by: Fred L. Templin <[EMAIL PROTECTED]>
---
--- linux-2.6.23/net/ipv6/sit.c.orig 2007-10-09 13:31:38.000000000
-0700
+++ linux-2.6.23/net/ipv6/sit.c 2007-11-06 15:32:27.000000000 -0800
@@ -16,6 +16,7 @@
* Changes:
* Roger Venning <[EMAIL PROTECTED]>: 6to4 support
* Nate Thompson <[EMAIL PROTECTED]>: 6to4 support
+ * Fred L. Templin <[EMAIL PROTECTED]>: isatap support
*/
#include <linux/module.h>
@@ -154,6 +155,14 @@ static struct ip_tunnel * ipip6_tunnel_l
struct net_device *dev;
char name[IFNAMSIZ];
+#if defined(CONFIG_IPV6_ISATAP)
+ /* ISATAP (RFC4214) - router address in daddr */
+ if (!strncmp(parms->name, "isatap", 6)) {
+ parms->i_key = parms->iph.daddr;
+ parms->iph.daddr = remote = 0;
+ }
+#endif
+
for (tp = __ipip6_bucket(parms); (t = *tp) != NULL; tp =
&t->next) {
if (local == t->parms.iph.saddr && remote ==
t->parms.iph.daddr)
return t;
@@ -182,6 +191,11 @@ static struct ip_tunnel * ipip6_tunnel_l
dev->init = ipip6_tunnel_init;
nt->parms = *parms;
+#if defined(CONFIG_IPV6_ISATAP)
+ if (!strncmp(dev->name, "isatap", 6))
+ dev->priv_flags |= IFF_ISATAP;
+#endif
+
if (register_netdevice(dev) < 0) {
free_netdev(dev);
goto failed;
@@ -382,6 +396,48 @@ static int ipip6_rcv(struct sk_buff *skb
IPCB(skb)->flags = 0;
skb->protocol = htons(ETH_P_IPV6);
skb->pkt_type = PACKET_HOST;
+#if defined(CONFIG_IPV6_ISATAP)
+ /* ISATAP (RFC4214) - check source address */
+ if (tunnel->dev->priv_flags & IFF_ISATAP) {
+ struct neighbour *neigh;
+ struct dst_entry *dst;
+ struct flowi fl;
+ struct in6_addr *addr6;
+ struct ipv6hdr *iph6;
+
+ /* from ISATAP router */
+ if (iph->saddr == tunnel->parms.i_key) goto accept;
+
+ iph6 = ipv6_hdr(skb);
+ addr6 = &iph6->saddr;
+
+ /* from legitimate previous hop */
+ memset(&fl, 0, sizeof(fl));
+ fl.proto = iph6->nexthdr;
+ ipv6_addr_copy(&fl.fl6_dst, addr6);
+ fl.oif = tunnel->dev->ifindex;
+ security_skb_classify_flow(skb, &fl);
+
+ if (!(dst = ip6_route_output(NULL, &fl)) ||
+ (dst->dev != tunnel->dev) ||
+ ((neigh = dst->neighbour) == NULL))
+ goto drop;
+
+ addr6 = (struct in6_addr*)&neigh->primary_key;
+
+ if (!(ipv6_addr_is_isatap(addr6)) ||
+ (addr6->s6_addr32[3] != iph->saddr)) {
+drop:
+ tunnel->stat.rx_errors++;
+ dst_release(dst);
+ kfree_skb(skb);
+ read_unlock(&ipip6_lock);
+ return 0;
+ }
+ dst_release(dst);
+ }
+accept:
+#endif
tunnel->stat.rx_packets++;
tunnel->stat.rx_bytes += skb->len;
skb->dev = tunnel->dev;
@@ -395,8 +451,6 @@ static int ipip6_rcv(struct sk_buff *skb
}
icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
- kfree_skb(skb);
- read_unlock(&ipip6_lock);
out:
return 0;
}
@@ -444,6 +498,31 @@ static int ipip6_tunnel_xmit(struct sk_b
if (skb->protocol != htons(ETH_P_IPV6))
goto tx_error;
+#if defined(CONFIG_IPV6_ISATAP)
+ /* ISATAP (RFC4214) - must come before 6to4 */
+ if (dev->priv_flags & IFF_ISATAP) {
+ struct neighbour *neigh = NULL;
+
+ if (skb->dst)
+ neigh = skb->dst->neighbour;
+
+ if (neigh == NULL) {
+ if (net_ratelimit())
+ printk(KERN_DEBUG "sit: nexthop ==
NULL\n");
+ goto tx_error;
+ }
+
+ addr6 = (struct in6_addr*)&neigh->primary_key;
+ addr_type = ipv6_addr_type(addr6);
+
+ if ((addr_type & IPV6_ADDR_UNICAST) &&
+ ipv6_addr_is_isatap(addr6))
+ dst = addr6->s6_addr32[3];
+ else
+ goto tx_error;
+ }
+#endif /* CONFIG_IPV6_ISATAP */
+
if (!dst)
dst = try_6to4(&iph6->daddr);
-
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