From c4d3efafcc933fd2ffd169d7dc4f980393a13796 Mon Sep 17 00:00:00 2001 From: Yasuyuki Kozakai Date: Thu, 15 Feb 2007 00:43:16 +0900 Subject: [PATCH] [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: Yasuyuki Kozakai Signed-off-by: YOSHIFUJI Hideaki Signed-off-by: David S. Miller --- net/ipv6/ip6_tunnel.c | 190 ++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 185 insertions(+), 5 deletions(-) diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c index 4546bb923a2..a6541495dea 100644 --- a/net/ipv6/ip6_tunnel.c +++ b/net/ipv6/ip6_tunnel.c @@ -1,14 +1,15 @@ /* - * IPv6 over IPv6 tunnel device + * IPv6 tunneling device * Linux INET6 implementation * * Authors: * Ville Nuorvala + * Yasuyuki Kozakai * * $Id$ * * 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 #include #include +#include #include #include #include @@ -41,6 +43,7 @@ #include #include +#include #include #include #include @@ -51,7 +54,7 @@ #include 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 @@ out: 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 @@ discard: 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 @@ tx_err_dst_release: 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"); -- 2.41.1