2 * Linux NET3: GRE over IP protocol decoder.
4 * Authors: Alexey Kuznetsov (kuznet@ms2.inr.ac.ru)
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
13 #include <linux/capability.h>
14 #include <linux/module.h>
15 #include <linux/types.h>
16 #include <linux/kernel.h>
17 #include <asm/uaccess.h>
18 #include <linux/skbuff.h>
19 #include <linux/netdevice.h>
21 #include <linux/tcp.h>
22 #include <linux/udp.h>
23 #include <linux/if_arp.h>
24 #include <linux/mroute.h>
25 #include <linux/init.h>
26 #include <linux/in6.h>
27 #include <linux/inetdevice.h>
28 #include <linux/igmp.h>
29 #include <linux/netfilter_ipv4.h>
30 #include <linux/etherdevice.h>
31 #include <linux/if_ether.h>
36 #include <net/protocol.h>
39 #include <net/checksum.h>
40 #include <net/dsfield.h>
41 #include <net/inet_ecn.h>
43 #include <net/net_namespace.h>
44 #include <net/netns/generic.h>
45 #include <net/rtnetlink.h>
49 #include <net/ip6_fib.h>
50 #include <net/ip6_route.h>
57 1. The most important issue is detecting local dead loops.
58 They would cause complete host lockup in transmit, which
59 would be "resolved" by stack overflow or, if queueing is enabled,
60 with infinite looping in net_bh.
62 We cannot track such dead loops during route installation,
63 it is infeasible task. The most general solutions would be
64 to keep skb->encapsulation counter (sort of local ttl),
65 and silently drop packet when it expires. It is the best
66 solution, but it supposes maintaing new variable in ALL
67 skb, even if no tunneling is used.
69 Current solution: HARD_TX_LOCK lock breaks dead loops.
73 2. Networking dead loops would not kill routers, but would really
74 kill network. IP hop limit plays role of "t->recursion" in this case,
75 if we copy it from packet being encapsulated to upper header.
76 It is very good solution, but it introduces two problems:
78 - Routing protocols, using packets with ttl=1 (OSPF, RIP2),
79 do not work over tunnels.
80 - traceroute does not work. I planned to relay ICMP from tunnel,
81 so that this problem would be solved and traceroute output
82 would even more informative. This idea appeared to be wrong:
83 only Linux complies to rfc1812 now (yes, guys, Linux is the only
84 true router now :-)), all routers (at least, in neighbourhood of mine)
85 return only 8 bytes of payload. It is the end.
87 Hence, if we want that OSPF worked or traceroute said something reasonable,
88 we should search for another solution.
90 One of them is to parse packet trying to detect inner encapsulation
91 made by our node. It is difficult or even impossible, especially,
92 taking into account fragmentation. TO be short, tt is not solution at all.
94 Current solution: The solution was UNEXPECTEDLY SIMPLE.
95 We force DF flag on tunnels with preconfigured hop limit,
96 that is ALL. :-) Well, it does not remove the problem completely,
97 but exponential growth of network traffic is changed to linear
98 (branches, that exceed pmtu are pruned) and tunnel mtu
99 fastly degrades to value <68, where looping stops.
100 Yes, it is not good if there exists a router in the loop,
101 which does not force DF, even when encapsulating packets have DF set.
102 But it is not our problem! Nobody could accuse us, we made
103 all that we could make. Even if it is your gated who injected
104 fatal route to network, even if it were you who configured
105 fatal static route: you are innocent. :-)
109 3. Really, ipv4/ipip.c, ipv4/ip_gre.c and ipv6/sit.c contain
110 practically identical code. It would be good to glue them
111 together, but it is not very evident, how to make them modular.
112 sit is integral part of IPv6, ipip and gre are naturally modular.
113 We could extract common parts (hash table, ioctl etc)
114 to a separate module (ip_tunnel.c).
119 static struct rtnl_link_ops ipgre_link_ops __read_mostly;
120 static int ipgre_tunnel_init(struct net_device *dev);
121 static void ipgre_tunnel_setup(struct net_device *dev);
122 static int ipgre_tunnel_bind_dev(struct net_device *dev);
124 /* Fallback tunnel: no source, no destination, no key, no options */
128 static int ipgre_net_id __read_mostly;
130 struct ip_tunnel *tunnels[4][HASH_SIZE];
132 struct net_device *fb_tunnel_dev;
135 /* Tunnel hash table */
145 We require exact key match i.e. if a key is present in packet
146 it will match only tunnel with the same key; if it is not present,
147 it will match only keyless tunnel.
149 All keysless packets, if not matched configured keyless tunnels
150 will match fallback tunnel.
153 #define HASH(addr) (((__force u32)addr^((__force u32)addr>>4))&0xF)
155 #define tunnels_r_l tunnels[3]
156 #define tunnels_r tunnels[2]
157 #define tunnels_l tunnels[1]
158 #define tunnels_wc tunnels[0]
160 * Locking : hash tables are protected by RCU and a spinlock
162 static DEFINE_SPINLOCK(ipgre_lock);
164 #define for_each_ip_tunnel_rcu(start) \
165 for (t = rcu_dereference(start); t; t = rcu_dereference(t->next))
167 /* Given src, dst and key, find appropriate for input tunnel. */
169 static struct ip_tunnel * ipgre_tunnel_lookup(struct net_device *dev,
170 __be32 remote, __be32 local,
171 __be32 key, __be16 gre_proto)
173 struct net *net = dev_net(dev);
174 int link = dev->ifindex;
175 unsigned h0 = HASH(remote);
176 unsigned h1 = HASH(key);
177 struct ip_tunnel *t, *cand = NULL;
178 struct ipgre_net *ign = net_generic(net, ipgre_net_id);
179 int dev_type = (gre_proto == htons(ETH_P_TEB)) ?
180 ARPHRD_ETHER : ARPHRD_IPGRE;
181 int score, cand_score = 4;
183 for_each_ip_tunnel_rcu(ign->tunnels_r_l[h0 ^ h1]) {
184 if (local != t->parms.iph.saddr ||
185 remote != t->parms.iph.daddr ||
186 key != t->parms.i_key ||
187 !(t->dev->flags & IFF_UP))
190 if (t->dev->type != ARPHRD_IPGRE &&
191 t->dev->type != dev_type)
195 if (t->parms.link != link)
197 if (t->dev->type != dev_type)
202 if (score < cand_score) {
208 for_each_ip_tunnel_rcu(ign->tunnels_r[h0 ^ h1]) {
209 if (remote != t->parms.iph.daddr ||
210 key != t->parms.i_key ||
211 !(t->dev->flags & IFF_UP))
214 if (t->dev->type != ARPHRD_IPGRE &&
215 t->dev->type != dev_type)
219 if (t->parms.link != link)
221 if (t->dev->type != dev_type)
226 if (score < cand_score) {
232 for_each_ip_tunnel_rcu(ign->tunnels_l[h1]) {
233 if ((local != t->parms.iph.saddr &&
234 (local != t->parms.iph.daddr ||
235 !ipv4_is_multicast(local))) ||
236 key != t->parms.i_key ||
237 !(t->dev->flags & IFF_UP))
240 if (t->dev->type != ARPHRD_IPGRE &&
241 t->dev->type != dev_type)
245 if (t->parms.link != link)
247 if (t->dev->type != dev_type)
252 if (score < cand_score) {
258 for_each_ip_tunnel_rcu(ign->tunnels_wc[h1]) {
259 if (t->parms.i_key != key ||
260 !(t->dev->flags & IFF_UP))
263 if (t->dev->type != ARPHRD_IPGRE &&
264 t->dev->type != dev_type)
268 if (t->parms.link != link)
270 if (t->dev->type != dev_type)
275 if (score < cand_score) {
284 dev = ign->fb_tunnel_dev;
285 if (dev->flags & IFF_UP)
286 return netdev_priv(dev);
291 static struct ip_tunnel **__ipgre_bucket(struct ipgre_net *ign,
292 struct ip_tunnel_parm *parms)
294 __be32 remote = parms->iph.daddr;
295 __be32 local = parms->iph.saddr;
296 __be32 key = parms->i_key;
297 unsigned h = HASH(key);
302 if (remote && !ipv4_is_multicast(remote)) {
307 return &ign->tunnels[prio][h];
310 static inline struct ip_tunnel **ipgre_bucket(struct ipgre_net *ign,
313 return __ipgre_bucket(ign, &t->parms);
316 static void ipgre_tunnel_link(struct ipgre_net *ign, struct ip_tunnel *t)
318 struct ip_tunnel **tp = ipgre_bucket(ign, t);
320 spin_lock_bh(&ipgre_lock);
322 rcu_assign_pointer(*tp, t);
323 spin_unlock_bh(&ipgre_lock);
326 static void ipgre_tunnel_unlink(struct ipgre_net *ign, struct ip_tunnel *t)
328 struct ip_tunnel **tp;
330 for (tp = ipgre_bucket(ign, t); *tp; tp = &(*tp)->next) {
332 spin_lock_bh(&ipgre_lock);
334 spin_unlock_bh(&ipgre_lock);
340 static struct ip_tunnel *ipgre_tunnel_find(struct net *net,
341 struct ip_tunnel_parm *parms,
344 __be32 remote = parms->iph.daddr;
345 __be32 local = parms->iph.saddr;
346 __be32 key = parms->i_key;
347 int link = parms->link;
348 struct ip_tunnel *t, **tp;
349 struct ipgre_net *ign = net_generic(net, ipgre_net_id);
351 for (tp = __ipgre_bucket(ign, parms); (t = *tp) != NULL; tp = &t->next)
352 if (local == t->parms.iph.saddr &&
353 remote == t->parms.iph.daddr &&
354 key == t->parms.i_key &&
355 link == t->parms.link &&
356 type == t->dev->type)
362 static struct ip_tunnel * ipgre_tunnel_locate(struct net *net,
363 struct ip_tunnel_parm *parms, int create)
365 struct ip_tunnel *t, *nt;
366 struct net_device *dev;
368 struct ipgre_net *ign = net_generic(net, ipgre_net_id);
370 t = ipgre_tunnel_find(net, parms, ARPHRD_IPGRE);
375 strlcpy(name, parms->name, IFNAMSIZ);
377 sprintf(name, "gre%%d");
379 dev = alloc_netdev(sizeof(*t), name, ipgre_tunnel_setup);
383 dev_net_set(dev, net);
385 if (strchr(name, '%')) {
386 if (dev_alloc_name(dev, name) < 0)
390 nt = netdev_priv(dev);
392 dev->rtnl_link_ops = &ipgre_link_ops;
394 dev->mtu = ipgre_tunnel_bind_dev(dev);
396 if (register_netdevice(dev) < 0)
400 ipgre_tunnel_link(ign, nt);
408 static void ipgre_tunnel_uninit(struct net_device *dev)
410 struct net *net = dev_net(dev);
411 struct ipgre_net *ign = net_generic(net, ipgre_net_id);
413 ipgre_tunnel_unlink(ign, netdev_priv(dev));
418 static void ipgre_err(struct sk_buff *skb, u32 info)
421 /* All the routers (except for Linux) return only
422 8 bytes of packet payload. It means, that precise relaying of
423 ICMP in the real Internet is absolutely infeasible.
425 Moreover, Cisco "wise men" put GRE key to the third word
426 in GRE header. It makes impossible maintaining even soft state for keyed
427 GRE tunnels with enabled checksum. Tell them "thank you".
429 Well, I wonder, rfc1812 was written by Cisco employee,
430 what the hell these idiots break standrads established
434 struct iphdr *iph = (struct iphdr *)skb->data;
435 __be16 *p = (__be16*)(skb->data+(iph->ihl<<2));
436 int grehlen = (iph->ihl<<2) + 4;
437 const int type = icmp_hdr(skb)->type;
438 const int code = icmp_hdr(skb)->code;
443 if (flags&(GRE_CSUM|GRE_KEY|GRE_SEQ|GRE_ROUTING|GRE_VERSION)) {
444 if (flags&(GRE_VERSION|GRE_ROUTING))
453 /* If only 8 bytes returned, keyed message will be dropped here */
454 if (skb_headlen(skb) < grehlen)
459 case ICMP_PARAMETERPROB:
462 case ICMP_DEST_UNREACH:
465 case ICMP_PORT_UNREACH:
466 /* Impossible event. */
468 case ICMP_FRAG_NEEDED:
469 /* Soft state for pmtu is maintained by IP core. */
472 /* All others are translated to HOST_UNREACH.
473 rfc2003 contains "deep thoughts" about NET_UNREACH,
474 I believe they are just ether pollution. --ANK
479 case ICMP_TIME_EXCEEDED:
480 if (code != ICMP_EXC_TTL)
486 t = ipgre_tunnel_lookup(skb->dev, iph->daddr, iph->saddr,
488 *(((__be32 *)p) + (grehlen / 4) - 1) : 0,
490 if (t == NULL || t->parms.iph.daddr == 0 ||
491 ipv4_is_multicast(t->parms.iph.daddr))
494 if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
497 if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
501 t->err_time = jiffies;
507 static inline void ipgre_ecn_decapsulate(struct iphdr *iph, struct sk_buff *skb)
509 if (INET_ECN_is_ce(iph->tos)) {
510 if (skb->protocol == htons(ETH_P_IP)) {
511 IP_ECN_set_ce(ip_hdr(skb));
512 } else if (skb->protocol == htons(ETH_P_IPV6)) {
513 IP6_ECN_set_ce(ipv6_hdr(skb));
519 ipgre_ecn_encapsulate(u8 tos, struct iphdr *old_iph, struct sk_buff *skb)
522 if (skb->protocol == htons(ETH_P_IP))
523 inner = old_iph->tos;
524 else if (skb->protocol == htons(ETH_P_IPV6))
525 inner = ipv6_get_dsfield((struct ipv6hdr *)old_iph);
526 return INET_ECN_encapsulate(tos, inner);
529 static int ipgre_rcv(struct sk_buff *skb)
537 struct ip_tunnel *tunnel;
542 if (!pskb_may_pull(skb, 16))
549 if (flags&(GRE_CSUM|GRE_KEY|GRE_ROUTING|GRE_SEQ|GRE_VERSION)) {
550 /* - Version must be 0.
551 - We do not support routing headers.
553 if (flags&(GRE_VERSION|GRE_ROUTING))
556 if (flags&GRE_CSUM) {
557 switch (skb->ip_summed) {
558 case CHECKSUM_COMPLETE:
559 csum = csum_fold(skb->csum);
565 csum = __skb_checksum_complete(skb);
566 skb->ip_summed = CHECKSUM_COMPLETE;
571 key = *(__be32*)(h + offset);
575 seqno = ntohl(*(__be32*)(h + offset));
580 gre_proto = *(__be16 *)(h + 2);
583 if ((tunnel = ipgre_tunnel_lookup(skb->dev,
584 iph->saddr, iph->daddr, key,
586 struct net_device_stats *stats = &tunnel->dev->stats;
590 skb->protocol = gre_proto;
591 /* WCCP version 1 and 2 protocol decoding.
592 * - Change protocol to IP
593 * - When dealing with WCCPv2, Skip extra 4 bytes in GRE header
595 if (flags == 0 && gre_proto == htons(ETH_P_WCCP)) {
596 skb->protocol = htons(ETH_P_IP);
597 if ((*(h + offset) & 0xF0) != 0x40)
601 skb->mac_header = skb->network_header;
602 __pskb_pull(skb, offset);
603 skb_postpull_rcsum(skb, skb_transport_header(skb), offset);
604 skb->pkt_type = PACKET_HOST;
605 #ifdef CONFIG_NET_IPGRE_BROADCAST
606 if (ipv4_is_multicast(iph->daddr)) {
607 /* Looped back packet, drop it! */
608 if (skb_rtable(skb)->fl.iif == 0)
611 skb->pkt_type = PACKET_BROADCAST;
615 if (((flags&GRE_CSUM) && csum) ||
616 (!(flags&GRE_CSUM) && tunnel->parms.i_flags&GRE_CSUM)) {
617 stats->rx_crc_errors++;
621 if (tunnel->parms.i_flags&GRE_SEQ) {
622 if (!(flags&GRE_SEQ) ||
623 (tunnel->i_seqno && (s32)(seqno - tunnel->i_seqno) < 0)) {
624 stats->rx_fifo_errors++;
628 tunnel->i_seqno = seqno + 1;
633 /* Warning: All skb pointers will be invalidated! */
634 if (tunnel->dev->type == ARPHRD_ETHER) {
635 if (!pskb_may_pull(skb, ETH_HLEN)) {
636 stats->rx_length_errors++;
642 skb->protocol = eth_type_trans(skb, tunnel->dev);
643 skb_postpull_rcsum(skb, eth_hdr(skb), ETH_HLEN);
647 stats->rx_bytes += len;
648 skb->dev = tunnel->dev;
652 skb_reset_network_header(skb);
653 ipgre_ecn_decapsulate(iph, skb);
659 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
668 static netdev_tx_t ipgre_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
670 struct ip_tunnel *tunnel = netdev_priv(dev);
671 struct net_device_stats *stats = &dev->stats;
672 struct netdev_queue *txq = netdev_get_tx_queue(dev, 0);
673 struct iphdr *old_iph = ip_hdr(skb);
677 struct rtable *rt; /* Route to the other host */
678 struct net_device *tdev; /* Device to other host */
679 struct iphdr *iph; /* Our new IP header */
680 unsigned int max_headroom; /* The extra header space needed */
685 if (dev->type == ARPHRD_ETHER)
686 IPCB(skb)->flags = 0;
688 if (dev->header_ops && dev->type == ARPHRD_IPGRE) {
690 tiph = (struct iphdr *)skb->data;
692 gre_hlen = tunnel->hlen;
693 tiph = &tunnel->parms.iph;
696 if ((dst = tiph->daddr) == 0) {
699 if (skb_dst(skb) == NULL) {
700 stats->tx_fifo_errors++;
704 if (skb->protocol == htons(ETH_P_IP)) {
705 rt = skb_rtable(skb);
706 if ((dst = rt->rt_gateway) == 0)
710 else if (skb->protocol == htons(ETH_P_IPV6)) {
711 struct in6_addr *addr6;
713 struct neighbour *neigh = skb_dst(skb)->neighbour;
718 addr6 = (struct in6_addr *)&neigh->primary_key;
719 addr_type = ipv6_addr_type(addr6);
721 if (addr_type == IPV6_ADDR_ANY) {
722 addr6 = &ipv6_hdr(skb)->daddr;
723 addr_type = ipv6_addr_type(addr6);
726 if ((addr_type & IPV6_ADDR_COMPATv4) == 0)
729 dst = addr6->s6_addr32[3];
739 if (skb->protocol == htons(ETH_P_IP))
744 struct flowi fl = { .oif = tunnel->parms.link,
747 .saddr = tiph->saddr,
748 .tos = RT_TOS(tos) } },
749 .proto = IPPROTO_GRE };
750 if (ip_route_output_key(dev_net(dev), &rt, &fl)) {
751 stats->tx_carrier_errors++;
755 tdev = rt->u.dst.dev;
765 mtu = dst_mtu(&rt->u.dst) - dev->hard_header_len - tunnel->hlen;
767 mtu = skb_dst(skb) ? dst_mtu(skb_dst(skb)) : dev->mtu;
770 skb_dst(skb)->ops->update_pmtu(skb_dst(skb), mtu);
772 if (skb->protocol == htons(ETH_P_IP)) {
773 df |= (old_iph->frag_off&htons(IP_DF));
775 if ((old_iph->frag_off&htons(IP_DF)) &&
776 mtu < ntohs(old_iph->tot_len)) {
777 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, htonl(mtu));
783 else if (skb->protocol == htons(ETH_P_IPV6)) {
784 struct rt6_info *rt6 = (struct rt6_info *)skb_dst(skb);
786 if (rt6 && mtu < dst_mtu(skb_dst(skb)) && mtu >= IPV6_MIN_MTU) {
787 if ((tunnel->parms.iph.daddr &&
788 !ipv4_is_multicast(tunnel->parms.iph.daddr)) ||
789 rt6->rt6i_dst.plen == 128) {
790 rt6->rt6i_flags |= RTF_MODIFIED;
791 skb_dst(skb)->metrics[RTAX_MTU-1] = mtu;
795 if (mtu >= IPV6_MIN_MTU && mtu < skb->len - tunnel->hlen + gre_hlen) {
796 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
803 if (tunnel->err_count > 0) {
804 if (time_before(jiffies,
805 tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
808 dst_link_failure(skb);
810 tunnel->err_count = 0;
813 max_headroom = LL_RESERVED_SPACE(tdev) + gre_hlen + rt->u.dst.header_len;
815 if (skb_headroom(skb) < max_headroom || skb_shared(skb)||
816 (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
817 struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
818 if (max_headroom > dev->needed_headroom)
819 dev->needed_headroom = max_headroom;
827 skb_set_owner_w(new_skb, skb->sk);
830 old_iph = ip_hdr(skb);
833 skb_reset_transport_header(skb);
834 skb_push(skb, gre_hlen);
835 skb_reset_network_header(skb);
836 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
837 IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED |
840 skb_dst_set(skb, &rt->u.dst);
843 * Push down and install the IPIP header.
848 iph->ihl = sizeof(struct iphdr) >> 2;
850 iph->protocol = IPPROTO_GRE;
851 iph->tos = ipgre_ecn_encapsulate(tos, old_iph, skb);
852 iph->daddr = rt->rt_dst;
853 iph->saddr = rt->rt_src;
855 if ((iph->ttl = tiph->ttl) == 0) {
856 if (skb->protocol == htons(ETH_P_IP))
857 iph->ttl = old_iph->ttl;
859 else if (skb->protocol == htons(ETH_P_IPV6))
860 iph->ttl = ((struct ipv6hdr *)old_iph)->hop_limit;
863 iph->ttl = dst_metric(&rt->u.dst, RTAX_HOPLIMIT);
866 ((__be16 *)(iph + 1))[0] = tunnel->parms.o_flags;
867 ((__be16 *)(iph + 1))[1] = (dev->type == ARPHRD_ETHER) ?
868 htons(ETH_P_TEB) : skb->protocol;
870 if (tunnel->parms.o_flags&(GRE_KEY|GRE_CSUM|GRE_SEQ)) {
871 __be32 *ptr = (__be32*)(((u8*)iph) + tunnel->hlen - 4);
873 if (tunnel->parms.o_flags&GRE_SEQ) {
875 *ptr = htonl(tunnel->o_seqno);
878 if (tunnel->parms.o_flags&GRE_KEY) {
879 *ptr = tunnel->parms.o_key;
882 if (tunnel->parms.o_flags&GRE_CSUM) {
884 *(__sum16*)ptr = ip_compute_csum((void*)(iph+1), skb->len - sizeof(struct iphdr));
894 dst_link_failure(skb);
902 static int ipgre_tunnel_bind_dev(struct net_device *dev)
904 struct net_device *tdev = NULL;
905 struct ip_tunnel *tunnel;
907 int hlen = LL_MAX_HEADER;
908 int mtu = ETH_DATA_LEN;
909 int addend = sizeof(struct iphdr) + 4;
911 tunnel = netdev_priv(dev);
912 iph = &tunnel->parms.iph;
914 /* Guess output device to choose reasonable mtu and needed_headroom */
917 struct flowi fl = { .oif = tunnel->parms.link,
919 { .daddr = iph->daddr,
921 .tos = RT_TOS(iph->tos) } },
922 .proto = IPPROTO_GRE };
924 if (!ip_route_output_key(dev_net(dev), &rt, &fl)) {
925 tdev = rt->u.dst.dev;
929 if (dev->type != ARPHRD_ETHER)
930 dev->flags |= IFF_POINTOPOINT;
933 if (!tdev && tunnel->parms.link)
934 tdev = __dev_get_by_index(dev_net(dev), tunnel->parms.link);
937 hlen = tdev->hard_header_len + tdev->needed_headroom;
940 dev->iflink = tunnel->parms.link;
942 /* Precalculate GRE options length */
943 if (tunnel->parms.o_flags&(GRE_CSUM|GRE_KEY|GRE_SEQ)) {
944 if (tunnel->parms.o_flags&GRE_CSUM)
946 if (tunnel->parms.o_flags&GRE_KEY)
948 if (tunnel->parms.o_flags&GRE_SEQ)
951 dev->needed_headroom = addend + hlen;
952 mtu -= dev->hard_header_len + addend;
957 tunnel->hlen = addend;
963 ipgre_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd)
966 struct ip_tunnel_parm p;
968 struct net *net = dev_net(dev);
969 struct ipgre_net *ign = net_generic(net, ipgre_net_id);
974 if (dev == ign->fb_tunnel_dev) {
975 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
979 t = ipgre_tunnel_locate(net, &p, 0);
982 t = netdev_priv(dev);
983 memcpy(&p, &t->parms, sizeof(p));
984 if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
991 if (!capable(CAP_NET_ADMIN))
995 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
999 if (p.iph.version != 4 || p.iph.protocol != IPPROTO_GRE ||
1000 p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)) ||
1001 ((p.i_flags|p.o_flags)&(GRE_VERSION|GRE_ROUTING)))
1004 p.iph.frag_off |= htons(IP_DF);
1006 if (!(p.i_flags&GRE_KEY))
1008 if (!(p.o_flags&GRE_KEY))
1011 t = ipgre_tunnel_locate(net, &p, cmd == SIOCADDTUNNEL);
1013 if (dev != ign->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
1015 if (t->dev != dev) {
1020 unsigned nflags = 0;
1022 t = netdev_priv(dev);
1024 if (ipv4_is_multicast(p.iph.daddr))
1025 nflags = IFF_BROADCAST;
1026 else if (p.iph.daddr)
1027 nflags = IFF_POINTOPOINT;
1029 if ((dev->flags^nflags)&(IFF_POINTOPOINT|IFF_BROADCAST)) {
1033 ipgre_tunnel_unlink(ign, t);
1034 t->parms.iph.saddr = p.iph.saddr;
1035 t->parms.iph.daddr = p.iph.daddr;
1036 t->parms.i_key = p.i_key;
1037 t->parms.o_key = p.o_key;
1038 memcpy(dev->dev_addr, &p.iph.saddr, 4);
1039 memcpy(dev->broadcast, &p.iph.daddr, 4);
1040 ipgre_tunnel_link(ign, t);
1041 netdev_state_change(dev);
1047 if (cmd == SIOCCHGTUNNEL) {
1048 t->parms.iph.ttl = p.iph.ttl;
1049 t->parms.iph.tos = p.iph.tos;
1050 t->parms.iph.frag_off = p.iph.frag_off;
1051 if (t->parms.link != p.link) {
1052 t->parms.link = p.link;
1053 dev->mtu = ipgre_tunnel_bind_dev(dev);
1054 netdev_state_change(dev);
1057 if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p)))
1060 err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
1065 if (!capable(CAP_NET_ADMIN))
1068 if (dev == ign->fb_tunnel_dev) {
1070 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
1073 if ((t = ipgre_tunnel_locate(net, &p, 0)) == NULL)
1076 if (t == netdev_priv(ign->fb_tunnel_dev))
1080 unregister_netdevice(dev);
1092 static int ipgre_tunnel_change_mtu(struct net_device *dev, int new_mtu)
1094 struct ip_tunnel *tunnel = netdev_priv(dev);
1096 new_mtu > 0xFFF8 - dev->hard_header_len - tunnel->hlen)
1102 /* Nice toy. Unfortunately, useless in real life :-)
1103 It allows to construct virtual multiprotocol broadcast "LAN"
1104 over the Internet, provided multicast routing is tuned.
1107 I have no idea was this bicycle invented before me,
1108 so that I had to set ARPHRD_IPGRE to a random value.
1109 I have an impression, that Cisco could make something similar,
1110 but this feature is apparently missing in IOS<=11.2(8).
1112 I set up 10.66.66/24 and fec0:6666:6666::0/96 as virtual networks
1113 with broadcast 224.66.66.66. If you have access to mbone, play with me :-)
1115 ping -t 255 224.66.66.66
1117 If nobody answers, mbone does not work.
1119 ip tunnel add Universe mode gre remote 224.66.66.66 local <Your_real_addr> ttl 255
1120 ip addr add 10.66.66.<somewhat>/24 dev Universe
1121 ifconfig Universe up
1122 ifconfig Universe add fe80::<Your_real_addr>/10
1123 ifconfig Universe add fec0:6666:6666::<Your_real_addr>/96
1126 ftp fec0:6666:6666::193.233.7.65
1131 static int ipgre_header(struct sk_buff *skb, struct net_device *dev,
1132 unsigned short type,
1133 const void *daddr, const void *saddr, unsigned len)
1135 struct ip_tunnel *t = netdev_priv(dev);
1136 struct iphdr *iph = (struct iphdr *)skb_push(skb, t->hlen);
1137 __be16 *p = (__be16*)(iph+1);
1139 memcpy(iph, &t->parms.iph, sizeof(struct iphdr));
1140 p[0] = t->parms.o_flags;
1144 * Set the source hardware address.
1148 memcpy(&iph->saddr, saddr, 4);
1150 memcpy(&iph->daddr, daddr, 4);
1157 static int ipgre_header_parse(const struct sk_buff *skb, unsigned char *haddr)
1159 struct iphdr *iph = (struct iphdr *) skb_mac_header(skb);
1160 memcpy(haddr, &iph->saddr, 4);
1164 static const struct header_ops ipgre_header_ops = {
1165 .create = ipgre_header,
1166 .parse = ipgre_header_parse,
1169 #ifdef CONFIG_NET_IPGRE_BROADCAST
1170 static int ipgre_open(struct net_device *dev)
1172 struct ip_tunnel *t = netdev_priv(dev);
1174 if (ipv4_is_multicast(t->parms.iph.daddr)) {
1175 struct flowi fl = { .oif = t->parms.link,
1177 { .daddr = t->parms.iph.daddr,
1178 .saddr = t->parms.iph.saddr,
1179 .tos = RT_TOS(t->parms.iph.tos) } },
1180 .proto = IPPROTO_GRE };
1182 if (ip_route_output_key(dev_net(dev), &rt, &fl))
1183 return -EADDRNOTAVAIL;
1184 dev = rt->u.dst.dev;
1186 if (__in_dev_get_rtnl(dev) == NULL)
1187 return -EADDRNOTAVAIL;
1188 t->mlink = dev->ifindex;
1189 ip_mc_inc_group(__in_dev_get_rtnl(dev), t->parms.iph.daddr);
1194 static int ipgre_close(struct net_device *dev)
1196 struct ip_tunnel *t = netdev_priv(dev);
1198 if (ipv4_is_multicast(t->parms.iph.daddr) && t->mlink) {
1199 struct in_device *in_dev;
1200 in_dev = inetdev_by_index(dev_net(dev), t->mlink);
1202 ip_mc_dec_group(in_dev, t->parms.iph.daddr);
1211 static const struct net_device_ops ipgre_netdev_ops = {
1212 .ndo_init = ipgre_tunnel_init,
1213 .ndo_uninit = ipgre_tunnel_uninit,
1214 #ifdef CONFIG_NET_IPGRE_BROADCAST
1215 .ndo_open = ipgre_open,
1216 .ndo_stop = ipgre_close,
1218 .ndo_start_xmit = ipgre_tunnel_xmit,
1219 .ndo_do_ioctl = ipgre_tunnel_ioctl,
1220 .ndo_change_mtu = ipgre_tunnel_change_mtu,
1223 static void ipgre_tunnel_setup(struct net_device *dev)
1225 dev->netdev_ops = &ipgre_netdev_ops;
1226 dev->destructor = free_netdev;
1228 dev->type = ARPHRD_IPGRE;
1229 dev->needed_headroom = LL_MAX_HEADER + sizeof(struct iphdr) + 4;
1230 dev->mtu = ETH_DATA_LEN - sizeof(struct iphdr) - 4;
1231 dev->flags = IFF_NOARP;
1234 dev->features |= NETIF_F_NETNS_LOCAL;
1235 dev->priv_flags &= ~IFF_XMIT_DST_RELEASE;
1238 static int ipgre_tunnel_init(struct net_device *dev)
1240 struct ip_tunnel *tunnel;
1243 tunnel = netdev_priv(dev);
1244 iph = &tunnel->parms.iph;
1247 strcpy(tunnel->parms.name, dev->name);
1249 memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4);
1250 memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4);
1253 #ifdef CONFIG_NET_IPGRE_BROADCAST
1254 if (ipv4_is_multicast(iph->daddr)) {
1257 dev->flags = IFF_BROADCAST;
1258 dev->header_ops = &ipgre_header_ops;
1262 dev->header_ops = &ipgre_header_ops;
1267 static void ipgre_fb_tunnel_init(struct net_device *dev)
1269 struct ip_tunnel *tunnel = netdev_priv(dev);
1270 struct iphdr *iph = &tunnel->parms.iph;
1271 struct ipgre_net *ign = net_generic(dev_net(dev), ipgre_net_id);
1274 strcpy(tunnel->parms.name, dev->name);
1277 iph->protocol = IPPROTO_GRE;
1279 tunnel->hlen = sizeof(struct iphdr) + 4;
1282 ign->tunnels_wc[0] = tunnel;
1286 static const struct net_protocol ipgre_protocol = {
1287 .handler = ipgre_rcv,
1288 .err_handler = ipgre_err,
1292 static void ipgre_destroy_tunnels(struct ipgre_net *ign, struct list_head *head)
1296 for (prio = 0; prio < 4; prio++) {
1298 for (h = 0; h < HASH_SIZE; h++) {
1299 struct ip_tunnel *t = ign->tunnels[prio][h];
1302 unregister_netdevice_queue(t->dev, head);
1309 static int __net_init ipgre_init_net(struct net *net)
1311 struct ipgre_net *ign = net_generic(net, ipgre_net_id);
1314 ign->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel), "gre0",
1315 ipgre_tunnel_setup);
1316 if (!ign->fb_tunnel_dev) {
1320 dev_net_set(ign->fb_tunnel_dev, net);
1322 ipgre_fb_tunnel_init(ign->fb_tunnel_dev);
1323 ign->fb_tunnel_dev->rtnl_link_ops = &ipgre_link_ops;
1325 if ((err = register_netdev(ign->fb_tunnel_dev)))
1331 free_netdev(ign->fb_tunnel_dev);
1336 static void __net_exit ipgre_exit_net(struct net *net)
1338 struct ipgre_net *ign;
1341 ign = net_generic(net, ipgre_net_id);
1343 ipgre_destroy_tunnels(ign, &list);
1344 unregister_netdevice_many(&list);
1348 static struct pernet_operations ipgre_net_ops = {
1349 .init = ipgre_init_net,
1350 .exit = ipgre_exit_net,
1351 .id = &ipgre_net_id,
1352 .size = sizeof(struct ipgre_net),
1355 static int ipgre_tunnel_validate(struct nlattr *tb[], struct nlattr *data[])
1363 if (data[IFLA_GRE_IFLAGS])
1364 flags |= nla_get_be16(data[IFLA_GRE_IFLAGS]);
1365 if (data[IFLA_GRE_OFLAGS])
1366 flags |= nla_get_be16(data[IFLA_GRE_OFLAGS]);
1367 if (flags & (GRE_VERSION|GRE_ROUTING))
1373 static int ipgre_tap_validate(struct nlattr *tb[], struct nlattr *data[])
1377 if (tb[IFLA_ADDRESS]) {
1378 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
1380 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
1381 return -EADDRNOTAVAIL;
1387 if (data[IFLA_GRE_REMOTE]) {
1388 memcpy(&daddr, nla_data(data[IFLA_GRE_REMOTE]), 4);
1394 return ipgre_tunnel_validate(tb, data);
1397 static void ipgre_netlink_parms(struct nlattr *data[],
1398 struct ip_tunnel_parm *parms)
1400 memset(parms, 0, sizeof(*parms));
1402 parms->iph.protocol = IPPROTO_GRE;
1407 if (data[IFLA_GRE_LINK])
1408 parms->link = nla_get_u32(data[IFLA_GRE_LINK]);
1410 if (data[IFLA_GRE_IFLAGS])
1411 parms->i_flags = nla_get_be16(data[IFLA_GRE_IFLAGS]);
1413 if (data[IFLA_GRE_OFLAGS])
1414 parms->o_flags = nla_get_be16(data[IFLA_GRE_OFLAGS]);
1416 if (data[IFLA_GRE_IKEY])
1417 parms->i_key = nla_get_be32(data[IFLA_GRE_IKEY]);
1419 if (data[IFLA_GRE_OKEY])
1420 parms->o_key = nla_get_be32(data[IFLA_GRE_OKEY]);
1422 if (data[IFLA_GRE_LOCAL])
1423 parms->iph.saddr = nla_get_be32(data[IFLA_GRE_LOCAL]);
1425 if (data[IFLA_GRE_REMOTE])
1426 parms->iph.daddr = nla_get_be32(data[IFLA_GRE_REMOTE]);
1428 if (data[IFLA_GRE_TTL])
1429 parms->iph.ttl = nla_get_u8(data[IFLA_GRE_TTL]);
1431 if (data[IFLA_GRE_TOS])
1432 parms->iph.tos = nla_get_u8(data[IFLA_GRE_TOS]);
1434 if (!data[IFLA_GRE_PMTUDISC] || nla_get_u8(data[IFLA_GRE_PMTUDISC]))
1435 parms->iph.frag_off = htons(IP_DF);
1438 static int ipgre_tap_init(struct net_device *dev)
1440 struct ip_tunnel *tunnel;
1442 tunnel = netdev_priv(dev);
1445 strcpy(tunnel->parms.name, dev->name);
1447 ipgre_tunnel_bind_dev(dev);
1452 static const struct net_device_ops ipgre_tap_netdev_ops = {
1453 .ndo_init = ipgre_tap_init,
1454 .ndo_uninit = ipgre_tunnel_uninit,
1455 .ndo_start_xmit = ipgre_tunnel_xmit,
1456 .ndo_set_mac_address = eth_mac_addr,
1457 .ndo_validate_addr = eth_validate_addr,
1458 .ndo_change_mtu = ipgre_tunnel_change_mtu,
1461 static void ipgre_tap_setup(struct net_device *dev)
1466 dev->netdev_ops = &ipgre_tap_netdev_ops;
1467 dev->destructor = free_netdev;
1470 dev->features |= NETIF_F_NETNS_LOCAL;
1473 static int ipgre_newlink(struct net *src_net, struct net_device *dev, struct nlattr *tb[],
1474 struct nlattr *data[])
1476 struct ip_tunnel *nt;
1477 struct net *net = dev_net(dev);
1478 struct ipgre_net *ign = net_generic(net, ipgre_net_id);
1482 nt = netdev_priv(dev);
1483 ipgre_netlink_parms(data, &nt->parms);
1485 if (ipgre_tunnel_find(net, &nt->parms, dev->type))
1488 if (dev->type == ARPHRD_ETHER && !tb[IFLA_ADDRESS])
1489 random_ether_addr(dev->dev_addr);
1491 mtu = ipgre_tunnel_bind_dev(dev);
1495 err = register_netdevice(dev);
1500 ipgre_tunnel_link(ign, nt);
1506 static int ipgre_changelink(struct net_device *dev, struct nlattr *tb[],
1507 struct nlattr *data[])
1509 struct ip_tunnel *t, *nt;
1510 struct net *net = dev_net(dev);
1511 struct ipgre_net *ign = net_generic(net, ipgre_net_id);
1512 struct ip_tunnel_parm p;
1515 if (dev == ign->fb_tunnel_dev)
1518 nt = netdev_priv(dev);
1519 ipgre_netlink_parms(data, &p);
1521 t = ipgre_tunnel_locate(net, &p, 0);
1529 if (dev->type != ARPHRD_ETHER) {
1530 unsigned nflags = 0;
1532 if (ipv4_is_multicast(p.iph.daddr))
1533 nflags = IFF_BROADCAST;
1534 else if (p.iph.daddr)
1535 nflags = IFF_POINTOPOINT;
1537 if ((dev->flags ^ nflags) &
1538 (IFF_POINTOPOINT | IFF_BROADCAST))
1542 ipgre_tunnel_unlink(ign, t);
1543 t->parms.iph.saddr = p.iph.saddr;
1544 t->parms.iph.daddr = p.iph.daddr;
1545 t->parms.i_key = p.i_key;
1546 if (dev->type != ARPHRD_ETHER) {
1547 memcpy(dev->dev_addr, &p.iph.saddr, 4);
1548 memcpy(dev->broadcast, &p.iph.daddr, 4);
1550 ipgre_tunnel_link(ign, t);
1551 netdev_state_change(dev);
1554 t->parms.o_key = p.o_key;
1555 t->parms.iph.ttl = p.iph.ttl;
1556 t->parms.iph.tos = p.iph.tos;
1557 t->parms.iph.frag_off = p.iph.frag_off;
1559 if (t->parms.link != p.link) {
1560 t->parms.link = p.link;
1561 mtu = ipgre_tunnel_bind_dev(dev);
1564 netdev_state_change(dev);
1570 static size_t ipgre_get_size(const struct net_device *dev)
1575 /* IFLA_GRE_IFLAGS */
1577 /* IFLA_GRE_OFLAGS */
1583 /* IFLA_GRE_LOCAL */
1585 /* IFLA_GRE_REMOTE */
1591 /* IFLA_GRE_PMTUDISC */
1596 static int ipgre_fill_info(struct sk_buff *skb, const struct net_device *dev)
1598 struct ip_tunnel *t = netdev_priv(dev);
1599 struct ip_tunnel_parm *p = &t->parms;
1601 NLA_PUT_U32(skb, IFLA_GRE_LINK, p->link);
1602 NLA_PUT_BE16(skb, IFLA_GRE_IFLAGS, p->i_flags);
1603 NLA_PUT_BE16(skb, IFLA_GRE_OFLAGS, p->o_flags);
1604 NLA_PUT_BE32(skb, IFLA_GRE_IKEY, p->i_key);
1605 NLA_PUT_BE32(skb, IFLA_GRE_OKEY, p->o_key);
1606 NLA_PUT_BE32(skb, IFLA_GRE_LOCAL, p->iph.saddr);
1607 NLA_PUT_BE32(skb, IFLA_GRE_REMOTE, p->iph.daddr);
1608 NLA_PUT_U8(skb, IFLA_GRE_TTL, p->iph.ttl);
1609 NLA_PUT_U8(skb, IFLA_GRE_TOS, p->iph.tos);
1610 NLA_PUT_U8(skb, IFLA_GRE_PMTUDISC, !!(p->iph.frag_off & htons(IP_DF)));
1618 static const struct nla_policy ipgre_policy[IFLA_GRE_MAX + 1] = {
1619 [IFLA_GRE_LINK] = { .type = NLA_U32 },
1620 [IFLA_GRE_IFLAGS] = { .type = NLA_U16 },
1621 [IFLA_GRE_OFLAGS] = { .type = NLA_U16 },
1622 [IFLA_GRE_IKEY] = { .type = NLA_U32 },
1623 [IFLA_GRE_OKEY] = { .type = NLA_U32 },
1624 [IFLA_GRE_LOCAL] = { .len = FIELD_SIZEOF(struct iphdr, saddr) },
1625 [IFLA_GRE_REMOTE] = { .len = FIELD_SIZEOF(struct iphdr, daddr) },
1626 [IFLA_GRE_TTL] = { .type = NLA_U8 },
1627 [IFLA_GRE_TOS] = { .type = NLA_U8 },
1628 [IFLA_GRE_PMTUDISC] = { .type = NLA_U8 },
1631 static struct rtnl_link_ops ipgre_link_ops __read_mostly = {
1633 .maxtype = IFLA_GRE_MAX,
1634 .policy = ipgre_policy,
1635 .priv_size = sizeof(struct ip_tunnel),
1636 .setup = ipgre_tunnel_setup,
1637 .validate = ipgre_tunnel_validate,
1638 .newlink = ipgre_newlink,
1639 .changelink = ipgre_changelink,
1640 .get_size = ipgre_get_size,
1641 .fill_info = ipgre_fill_info,
1644 static struct rtnl_link_ops ipgre_tap_ops __read_mostly = {
1646 .maxtype = IFLA_GRE_MAX,
1647 .policy = ipgre_policy,
1648 .priv_size = sizeof(struct ip_tunnel),
1649 .setup = ipgre_tap_setup,
1650 .validate = ipgre_tap_validate,
1651 .newlink = ipgre_newlink,
1652 .changelink = ipgre_changelink,
1653 .get_size = ipgre_get_size,
1654 .fill_info = ipgre_fill_info,
1658 * And now the modules code and kernel interface.
1661 static int __init ipgre_init(void)
1665 printk(KERN_INFO "GRE over IPv4 tunneling driver\n");
1667 err = register_pernet_device(&ipgre_net_ops);
1671 err = inet_add_protocol(&ipgre_protocol, IPPROTO_GRE);
1673 printk(KERN_INFO "ipgre init: can't add protocol\n");
1674 goto add_proto_failed;
1677 err = rtnl_link_register(&ipgre_link_ops);
1679 goto rtnl_link_failed;
1681 err = rtnl_link_register(&ipgre_tap_ops);
1683 goto tap_ops_failed;
1689 rtnl_link_unregister(&ipgre_link_ops);
1691 inet_del_protocol(&ipgre_protocol, IPPROTO_GRE);
1693 unregister_pernet_device(&ipgre_net_ops);
1697 static void __exit ipgre_fini(void)
1699 rtnl_link_unregister(&ipgre_tap_ops);
1700 rtnl_link_unregister(&ipgre_link_ops);
1701 if (inet_del_protocol(&ipgre_protocol, IPPROTO_GRE) < 0)
1702 printk(KERN_INFO "ipgre close: can't remove protocol\n");
1703 unregister_pernet_device(&ipgre_net_ops);
1706 module_init(ipgre_init);
1707 module_exit(ipgre_fini);
1708 MODULE_LICENSE("GPL");
1709 MODULE_ALIAS_RTNL_LINK("gre");
1710 MODULE_ALIAS_RTNL_LINK("gretap");