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Commit c4d3efaf authored by Yasuyuki Kozakai's avatar Yasuyuki Kozakai Committed by David S. Miller
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[IPV6] IP6TUNNEL: Add support to IPv4 over IPv6 tunnel. 



Some notes
- Protocol number IPPROTO_IPIP is used for IPv4 over IPv6 packets.
- If IP6_TNL_F_USE_ORIG_TCLASS is set, TOS in IPv4 header is copied to
  Traffic Class in outer IPv6 header on xmit.
- IP6_TNL_F_USE_ORIG_FLOWLABEL is ignored on xmit of IPv4 packets, because
  IPv4 header does not have flow label.
- Kernel sends ICMP error if IPv4 packet is too big on xmit, even if
  DF flag is not set.

Signed-off-by: default avatarYasuyuki Kozakai <yasuyuki.kozakai@toshiba.co.jp>
Signed-off-by: default avatarYOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 61ec2aec

net/ipv6/ip6_tunnel.c

+185 −5
Original line number Diff line number Diff line 
/*

 *	IPv6 over IPv6 tunnel device

 *	IPv6 tunneling device

 *	Linux INET6 implementation

 *

 *	Authors:

 *	Ville Nuorvala		<vnuorval@tcs.hut.fi>

 *	Yasuyuki Kozakai	<kozakai@linux-ipv6.org>

 *

 *	$Id$

 *

 *      Based on:

 *      linux/net/ipv6/sit.c

 *      linux/net/ipv6/sit.c and linux/net/ipv4/ipip.c

 *

 *      RFC 2473

 *
@@ -24,6 +25,7 @@ 
#include <linux/errno.h>

#include <linux/types.h>

#include <linux/sockios.h>

#include <linux/icmp.h>

#include <linux/if.h>

#include <linux/in.h>

#include <linux/ip.h>
@@ -41,6 +43,7 @@ 
#include <asm/uaccess.h>

#include <asm/atomic.h>



#include <net/icmp.h>

#include <net/ip.h>

#include <net/ipv6.h>

#include <net/ip6_route.h>
@@ -51,7 +54,7 @@ 
#include <net/inet_ecn.h>



MODULE_AUTHOR("Ville Nuorvala");

MODULE_DESCRIPTION("IPv6-in-IPv6 tunnel");

MODULE_DESCRIPTION("IPv6 tunneling device");

MODULE_LICENSE("GPL");



#define IPV6_TLV_TEL_DST_SIZE 8
@@ -63,6 +66,7 @@ MODULE_LICENSE("GPL"); 
#endif



#define IPV6_TCLASS_MASK (IPV6_FLOWINFO_MASK & ~IPV6_FLOWLABEL_MASK)

#define IPV6_TCLASS_SHIFT 20



#define HASH_SIZE  32
@@ -469,6 +473,104 @@ ip6_tnl_err(struct sk_buff *skb, struct inet6_skb_parm *opt, 
	return err;

}



static int

ip4ip6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,

	   int type, int code, int offset, __u32 info)

{

	int rel_msg = 0;

	int rel_type = type;

	int rel_code = code;

	__u32 rel_info = info;

	int err;

	struct sk_buff *skb2;

	struct iphdr *eiph;

	struct flowi fl;

	struct rtable *rt;



	err = ip6_tnl_err(skb, opt, &rel_type, &rel_code, &rel_msg, &rel_info,

			  offset);

	if (err < 0)

		return err;



	if (rel_msg == 0)

		return 0;



	switch (rel_type) {

	case ICMPV6_DEST_UNREACH:

		if (rel_code != ICMPV6_ADDR_UNREACH)

			return 0;

		rel_type = ICMP_DEST_UNREACH;

		rel_code = ICMP_HOST_UNREACH;

		break;

	case ICMPV6_PKT_TOOBIG:

		if (rel_code != 0)

			return 0;

		rel_type = ICMP_DEST_UNREACH;

		rel_code = ICMP_FRAG_NEEDED;

		break;

	default:

		return 0;

	}



	if (!pskb_may_pull(skb, offset + sizeof(struct iphdr)))

		return 0;



	skb2 = skb_clone(skb, GFP_ATOMIC);

	if (!skb2)

		return 0;



	dst_release(skb2->dst);

	skb2->dst = NULL;

	skb_pull(skb2, offset);

	skb2->nh.raw = skb2->data;

	eiph = skb2->nh.iph;



	/* Try to guess incoming interface */

	memset(&fl, 0, sizeof(fl));

	fl.fl4_dst = eiph->saddr;

	fl.fl4_tos = RT_TOS(eiph->tos);

	fl.proto = IPPROTO_IPIP;

	if (ip_route_output_key(&rt, &fl))

		goto out;



	skb2->dev = rt->u.dst.dev;



	/* route "incoming" packet */

	if (rt->rt_flags & RTCF_LOCAL) {

		ip_rt_put(rt);

		rt = NULL;

		fl.fl4_dst = eiph->daddr;

		fl.fl4_src = eiph->saddr;

		fl.fl4_tos = eiph->tos;

		if (ip_route_output_key(&rt, &fl) ||

		    rt->u.dst.dev->type != ARPHRD_TUNNEL) {

			ip_rt_put(rt);

			goto out;

		}

	} else {

		ip_rt_put(rt);

		if (ip_route_input(skb2, eiph->daddr, eiph->saddr, eiph->tos,

				   skb2->dev) ||

		    skb2->dst->dev->type != ARPHRD_TUNNEL)

			goto out;

	}



	/* change mtu on this route */

	if (rel_type == ICMP_DEST_UNREACH && rel_code == ICMP_FRAG_NEEDED) {

		if (rel_info > dst_mtu(skb2->dst))

			goto out;



		skb2->dst->ops->update_pmtu(skb2->dst, rel_info);

		rel_info = htonl(rel_info);

	}



	icmp_send(skb2, rel_type, rel_code, rel_info);



out:

	kfree_skb(skb2);

	return 0;

}



static int

ip6ip6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,

	   int type, int code, int offset, __u32 info)
@@ -513,6 +615,19 @@ ip6ip6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, 
	return 0;

}



static void ip4ip6_dscp_ecn_decapsulate(struct ip6_tnl *t,

					struct ipv6hdr *ipv6h,

					struct sk_buff *skb)

{

	__u8 dsfield = ipv6_get_dsfield(ipv6h) & ~INET_ECN_MASK;



	if (t->parms.flags & IP6_TNL_F_RCV_DSCP_COPY)

		ipv4_change_dsfield(skb->nh.iph, INET_ECN_MASK, dsfield);



	if (INET_ECN_is_ce(dsfield))

		IP_ECN_set_ce(skb->nh.iph);

}



static void ip6ip6_dscp_ecn_decapsulate(struct ip6_tnl *t,

					struct ipv6hdr *ipv6h,

					struct sk_buff *skb)
@@ -605,6 +720,11 @@ static int ip6_tnl_rcv(struct sk_buff *skb, __u16 protocol, 
	return 0;

}



static int ip4ip6_rcv(struct sk_buff *skb)

{

	return ip6_tnl_rcv(skb, ETH_P_IP, ip4ip6_dscp_ecn_decapsulate);

}



static int ip6ip6_rcv(struct sk_buff *skb)

{

	return ip6_tnl_rcv(skb, ETH_P_IPV6, ip6ip6_dscp_ecn_decapsulate);
@@ -691,7 +811,7 @@ static inline int ip6_tnl_xmit_ctl(struct ip6_tnl *t) 
 *   it.

 *

 * Return:

 *   0

 *   0 on success

 *   -1 fail

 *   %-EMSGSIZE message too big. return mtu in this case.

 **/
@@ -808,6 +928,44 @@ static int ip6_tnl_xmit2(struct sk_buff *skb, 
	return err;

}



static inline int

ip4ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)

{

	struct ip6_tnl *t = netdev_priv(dev);

	struct iphdr  *iph = skb->nh.iph;

	int encap_limit = -1;

	struct flowi fl;

	__u8 dsfield;

	__u32 mtu;

	int err;



	if (!ip6_tnl_xmit_ctl(t))

		return -1;



	if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT))

		encap_limit = t->parms.encap_limit;



	memcpy(&fl, &t->fl, sizeof (fl));

	fl.proto = IPPROTO_IPIP;



	dsfield = ipv4_get_dsfield(iph);



	if ((t->parms.flags & IP6_TNL_F_USE_ORIG_TCLASS))

		fl.fl6_flowlabel |= ntohl(((__u32)iph->tos << IPV6_TCLASS_SHIFT)

					  & IPV6_TCLASS_MASK);



	err = ip6_tnl_xmit2(skb, dev, dsfield, &fl, encap_limit, &mtu);

	if (err != 0) {

		/* XXX: send ICMP error even if DF is not set. */

		if (err == -EMSGSIZE)

			icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,

				  htonl(mtu));

		return -1;

	}



	return 0;

}



static inline int

ip6ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)

{
@@ -867,6 +1025,9 @@ ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev) 
	}



	switch (skb->protocol) {

	case __constant_htons(ETH_P_IP):

		ret = ip4ip6_tnl_xmit(skb, dev);

		break;

	case __constant_htons(ETH_P_IPV6):

		ret = ip6ip6_tnl_xmit(skb, dev);

		break;
@@ -1199,6 +1360,12 @@ ip6ip6_fb_tnl_dev_init(struct net_device *dev) 
	return 0;

}



static struct xfrm6_tunnel ip4ip6_handler = {

	.handler	= ip4ip6_rcv,

	.err_handler	= ip4ip6_err,

	.priority	=	1,

};



static struct xfrm6_tunnel ip6ip6_handler = {

	.handler	= ip6ip6_rcv,

	.err_handler	= ip6ip6_err,
@@ -1215,9 +1382,16 @@ static int __init ip6_tunnel_init(void) 
{

	int  err;



	if (xfrm6_tunnel_register(&ip4ip6_handler, AF_INET)) {

		printk(KERN_ERR "ip4ip6 init: can't register tunnel\n");

		err = -EAGAIN;

		goto out;

	}



	if (xfrm6_tunnel_register(&ip6ip6_handler, AF_INET6)) {

		printk(KERN_ERR "ip6ip6 init: can't register tunnel\n");

		return -EAGAIN;

		err = -EAGAIN;

		goto unreg_ip4ip6;

	}

	ip6ip6_fb_tnl_dev = alloc_netdev(sizeof(struct ip6_tnl), "ip6tnl0",

					 ip6ip6_tnl_dev_setup);
@@ -1235,6 +1409,9 @@ static int __init ip6_tunnel_init(void) 
	return 0;

fail:

	xfrm6_tunnel_deregister(&ip6ip6_handler, AF_INET6);

unreg_ip4ip6:

	xfrm6_tunnel_deregister(&ip4ip6_handler, AF_INET);

out:

	return err;

}
@@ -1258,6 +1435,9 @@ static void __exit ip6ip6_destroy_tunnels(void) 


static void __exit ip6_tunnel_cleanup(void)

{

	if (xfrm6_tunnel_deregister(&ip4ip6_handler, AF_INET))

		printk(KERN_INFO "ip4ip6 close: can't deregister tunnel\n");



	if (xfrm6_tunnel_deregister(&ip6ip6_handler, AF_INET6))

		printk(KERN_INFO "ip6ip6 close: can't deregister tunnel\n");