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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
15 #include <linux/capability.h>
16 #include <linux/module.h>
17 #include <linux/types.h>
18 #include <linux/kernel.h>
19 #include <linux/slab.h>
20 #include <asm/uaccess.h>
21 #include <linux/skbuff.h>
22 #include <linux/netdevice.h>
24 #include <linux/tcp.h>
25 #include <linux/udp.h>
26 #include <linux/if_arp.h>
27 #include <linux/if_vlan.h>
28 #include <linux/init.h>
29 #include <linux/in6.h>
30 #include <linux/inetdevice.h>
31 #include <linux/igmp.h>
32 #include <linux/netfilter_ipv4.h>
33 #include <linux/etherdevice.h>
34 #include <linux/if_ether.h>
39 #include <net/protocol.h>
40 #include <net/ip_tunnels.h>
42 #include <net/checksum.h>
43 #include <net/dsfield.h>
44 #include <net/inet_ecn.h>
46 #include <net/net_namespace.h>
47 #include <net/netns/generic.h>
48 #include <net/rtnetlink.h>
50 #include <net/dst_metadata.h>
52 #if IS_ENABLED(CONFIG_IPV6)
54 #include <net/ip6_fib.h>
55 #include <net/ip6_route.h>
62 1. The most important issue is detecting local dead loops.
63 They would cause complete host lockup in transmit, which
64 would be "resolved" by stack overflow or, if queueing is enabled,
65 with infinite looping in net_bh.
67 We cannot track such dead loops during route installation,
68 it is infeasible task. The most general solutions would be
69 to keep skb->encapsulation counter (sort of local ttl),
70 and silently drop packet when it expires. It is a good
71 solution, but it supposes maintaining new variable in ALL
72 skb, even if no tunneling is used.
74 Current solution: xmit_recursion breaks dead loops. This is a percpu
75 counter, since when we enter the first ndo_xmit(), cpu migration is
76 forbidden. We force an exit if this counter reaches RECURSION_LIMIT
78 2. Networking dead loops would not kill routers, but would really
79 kill network. IP hop limit plays role of "t->recursion" in this case,
80 if we copy it from packet being encapsulated to upper header.
81 It is very good solution, but it introduces two problems:
83 - Routing protocols, using packets with ttl=1 (OSPF, RIP2),
84 do not work over tunnels.
85 - traceroute does not work. I planned to relay ICMP from tunnel,
86 so that this problem would be solved and traceroute output
87 would even more informative. This idea appeared to be wrong:
88 only Linux complies to rfc1812 now (yes, guys, Linux is the only
89 true router now :-)), all routers (at least, in neighbourhood of mine)
90 return only 8 bytes of payload. It is the end.
92 Hence, if we want that OSPF worked or traceroute said something reasonable,
93 we should search for another solution.
95 One of them is to parse packet trying to detect inner encapsulation
96 made by our node. It is difficult or even impossible, especially,
97 taking into account fragmentation. TO be short, ttl is not solution at all.
99 Current solution: The solution was UNEXPECTEDLY SIMPLE.
100 We force DF flag on tunnels with preconfigured hop limit,
101 that is ALL. :-) Well, it does not remove the problem completely,
102 but exponential growth of network traffic is changed to linear
103 (branches, that exceed pmtu are pruned) and tunnel mtu
104 rapidly degrades to value <68, where looping stops.
105 Yes, it is not good if there exists a router in the loop,
106 which does not force DF, even when encapsulating packets have DF set.
107 But it is not our problem! Nobody could accuse us, we made
108 all that we could make. Even if it is your gated who injected
109 fatal route to network, even if it were you who configured
110 fatal static route: you are innocent. :-)
115 static bool log_ecn_error
= true;
116 module_param(log_ecn_error
, bool, 0644);
117 MODULE_PARM_DESC(log_ecn_error
, "Log packets received with corrupted ECN");
119 static struct rtnl_link_ops ipgre_link_ops __read_mostly
;
120 static int ipgre_tunnel_init(struct net_device
*dev
);
122 static int ipgre_net_id __read_mostly
;
123 static int gre_tap_net_id __read_mostly
;
125 static int ip_gre_calc_hlen(__be16 o_flags
)
129 if (o_flags
& TUNNEL_CSUM
)
131 if (o_flags
& TUNNEL_KEY
)
133 if (o_flags
& TUNNEL_SEQ
)
138 static __be16
gre_flags_to_tnl_flags(__be16 flags
)
142 if (flags
& GRE_CSUM
)
143 tflags
|= TUNNEL_CSUM
;
144 if (flags
& GRE_ROUTING
)
145 tflags
|= TUNNEL_ROUTING
;
147 tflags
|= TUNNEL_KEY
;
149 tflags
|= TUNNEL_SEQ
;
150 if (flags
& GRE_STRICT
)
151 tflags
|= TUNNEL_STRICT
;
153 tflags
|= TUNNEL_REC
;
154 if (flags
& GRE_VERSION
)
155 tflags
|= TUNNEL_VERSION
;
160 static __be16
tnl_flags_to_gre_flags(__be16 tflags
)
164 if (tflags
& TUNNEL_CSUM
)
166 if (tflags
& TUNNEL_ROUTING
)
167 flags
|= GRE_ROUTING
;
168 if (tflags
& TUNNEL_KEY
)
170 if (tflags
& TUNNEL_SEQ
)
172 if (tflags
& TUNNEL_STRICT
)
174 if (tflags
& TUNNEL_REC
)
176 if (tflags
& TUNNEL_VERSION
)
177 flags
|= GRE_VERSION
;
182 static int parse_gre_header(struct sk_buff
*skb
, struct tnl_ptk_info
*tpi
,
185 const struct gre_base_hdr
*greh
;
189 if (unlikely(!pskb_may_pull(skb
, sizeof(struct gre_base_hdr
))))
192 greh
= (struct gre_base_hdr
*)skb_transport_header(skb
);
193 if (unlikely(greh
->flags
& (GRE_VERSION
| GRE_ROUTING
)))
196 tpi
->flags
= gre_flags_to_tnl_flags(greh
->flags
);
197 hdr_len
= ip_gre_calc_hlen(tpi
->flags
);
199 if (!pskb_may_pull(skb
, hdr_len
))
202 greh
= (struct gre_base_hdr
*)skb_transport_header(skb
);
203 tpi
->proto
= greh
->protocol
;
205 options
= (__be32
*)(greh
+ 1);
206 if (greh
->flags
& GRE_CSUM
) {
207 if (skb_checksum_simple_validate(skb
)) {
212 skb_checksum_try_convert(skb
, IPPROTO_GRE
, 0,
213 null_compute_pseudo
);
217 if (greh
->flags
& GRE_KEY
) {
223 if (unlikely(greh
->flags
& GRE_SEQ
)) {
229 /* WCCP version 1 and 2 protocol decoding.
230 * - Change protocol to IP
231 * - When dealing with WCCPv2, Skip extra 4 bytes in GRE header
233 if (greh
->flags
== 0 && tpi
->proto
== htons(ETH_P_WCCP
)) {
234 tpi
->proto
= htons(ETH_P_IP
);
235 if ((*(u8
*)options
& 0xF0) != 0x40) {
237 if (!pskb_may_pull(skb
, hdr_len
))
241 return iptunnel_pull_header(skb
, hdr_len
, tpi
->proto
, false);
244 static void ipgre_err(struct sk_buff
*skb
, u32 info
,
245 const struct tnl_ptk_info
*tpi
)
248 /* All the routers (except for Linux) return only
249 8 bytes of packet payload. It means, that precise relaying of
250 ICMP in the real Internet is absolutely infeasible.
252 Moreover, Cisco "wise men" put GRE key to the third word
253 in GRE header. It makes impossible maintaining even soft
254 state for keyed GRE tunnels with enabled checksum. Tell
257 Well, I wonder, rfc1812 was written by Cisco employee,
258 what the hell these idiots break standards established
261 struct net
*net
= dev_net(skb
->dev
);
262 struct ip_tunnel_net
*itn
;
263 const struct iphdr
*iph
;
264 const int type
= icmp_hdr(skb
)->type
;
265 const int code
= icmp_hdr(skb
)->code
;
270 case ICMP_PARAMETERPROB
:
273 case ICMP_DEST_UNREACH
:
276 case ICMP_PORT_UNREACH
:
277 /* Impossible event. */
280 /* All others are translated to HOST_UNREACH.
281 rfc2003 contains "deep thoughts" about NET_UNREACH,
282 I believe they are just ether pollution. --ANK
288 case ICMP_TIME_EXCEEDED
:
289 if (code
!= ICMP_EXC_TTL
)
297 if (tpi
->proto
== htons(ETH_P_TEB
))
298 itn
= net_generic(net
, gre_tap_net_id
);
300 itn
= net_generic(net
, ipgre_net_id
);
302 iph
= (const struct iphdr
*)(icmp_hdr(skb
) + 1);
303 t
= ip_tunnel_lookup(itn
, skb
->dev
->ifindex
, tpi
->flags
,
304 iph
->daddr
, iph
->saddr
, tpi
->key
);
309 if (t
->parms
.iph
.daddr
== 0 ||
310 ipv4_is_multicast(t
->parms
.iph
.daddr
))
313 if (t
->parms
.iph
.ttl
== 0 && type
== ICMP_TIME_EXCEEDED
)
316 if (time_before(jiffies
, t
->err_time
+ IPTUNNEL_ERR_TIMEO
))
320 t
->err_time
= jiffies
;
323 static void gre_err(struct sk_buff
*skb
, u32 info
)
325 /* All the routers (except for Linux) return only
326 * 8 bytes of packet payload. It means, that precise relaying of
327 * ICMP in the real Internet is absolutely infeasible.
329 * Moreover, Cisco "wise men" put GRE key to the third word
330 * in GRE header. It makes impossible maintaining even soft
332 * GRE tunnels with enabled checksum. Tell them "thank you".
334 * Well, I wonder, rfc1812 was written by Cisco employee,
335 * what the hell these idiots break standards established
339 const int type
= icmp_hdr(skb
)->type
;
340 const int code
= icmp_hdr(skb
)->code
;
341 struct tnl_ptk_info tpi
;
342 bool csum_err
= false;
344 if (parse_gre_header(skb
, &tpi
, &csum_err
)) {
345 if (!csum_err
) /* ignore csum errors. */
349 if (type
== ICMP_DEST_UNREACH
&& code
== ICMP_FRAG_NEEDED
) {
350 ipv4_update_pmtu(skb
, dev_net(skb
->dev
), info
,
351 skb
->dev
->ifindex
, 0, IPPROTO_GRE
, 0);
354 if (type
== ICMP_REDIRECT
) {
355 ipv4_redirect(skb
, dev_net(skb
->dev
), skb
->dev
->ifindex
, 0,
360 ipgre_err(skb
, info
, &tpi
);
363 static __be64
key_to_tunnel_id(__be32 key
)
366 return (__force __be64
)((__force u32
)key
);
368 return (__force __be64
)((__force u64
)key
<< 32);
372 /* Returns the least-significant 32 bits of a __be64. */
373 static __be32
tunnel_id_to_key(__be64 x
)
376 return (__force __be32
)x
;
378 return (__force __be32
)((__force u64
)x
>> 32);
382 static int ipgre_rcv(struct sk_buff
*skb
, const struct tnl_ptk_info
*tpi
)
384 struct net
*net
= dev_net(skb
->dev
);
385 struct metadata_dst
*tun_dst
= NULL
;
386 struct ip_tunnel_net
*itn
;
387 const struct iphdr
*iph
;
388 struct ip_tunnel
*tunnel
;
390 if (tpi
->proto
== htons(ETH_P_TEB
))
391 itn
= net_generic(net
, gre_tap_net_id
);
393 itn
= net_generic(net
, ipgre_net_id
);
396 tunnel
= ip_tunnel_lookup(itn
, skb
->dev
->ifindex
, tpi
->flags
,
397 iph
->saddr
, iph
->daddr
, tpi
->key
);
400 skb_pop_mac_header(skb
);
401 if (tunnel
->collect_md
) {
405 flags
= tpi
->flags
& (TUNNEL_CSUM
| TUNNEL_KEY
);
406 tun_id
= key_to_tunnel_id(tpi
->key
);
407 tun_dst
= ip_tun_rx_dst(skb
, flags
, tun_id
, 0);
409 return PACKET_REJECT
;
412 ip_tunnel_rcv(tunnel
, skb
, tpi
, tun_dst
, log_ecn_error
);
415 return PACKET_REJECT
;
418 static int gre_rcv(struct sk_buff
*skb
)
420 struct tnl_ptk_info tpi
;
421 bool csum_err
= false;
423 #ifdef CONFIG_NET_IPGRE_BROADCAST
424 if (ipv4_is_multicast(ip_hdr(skb
)->daddr
)) {
425 /* Looped back packet, drop it! */
426 if (rt_is_output_route(skb_rtable(skb
)))
431 if (parse_gre_header(skb
, &tpi
, &csum_err
) < 0)
434 if (ipgre_rcv(skb
, &tpi
) == PACKET_RCVD
)
437 icmp_send(skb
, ICMP_DEST_UNREACH
, ICMP_PORT_UNREACH
, 0);
443 static __sum16
gre_checksum(struct sk_buff
*skb
)
447 if (skb
->ip_summed
== CHECKSUM_PARTIAL
)
448 csum
= lco_csum(skb
);
450 csum
= skb_checksum(skb
, 0, skb
->len
, 0);
451 return csum_fold(csum
);
454 static void build_header(struct sk_buff
*skb
, int hdr_len
, __be16 flags
,
455 __be16 proto
, __be32 key
, __be32 seq
)
457 struct gre_base_hdr
*greh
;
459 skb_push(skb
, hdr_len
);
461 skb_reset_transport_header(skb
);
462 greh
= (struct gre_base_hdr
*)skb
->data
;
463 greh
->flags
= tnl_flags_to_gre_flags(flags
);
464 greh
->protocol
= proto
;
466 if (flags
& (TUNNEL_KEY
| TUNNEL_CSUM
| TUNNEL_SEQ
)) {
467 __be32
*ptr
= (__be32
*)(((u8
*)greh
) + hdr_len
- 4);
469 if (flags
& TUNNEL_SEQ
) {
473 if (flags
& TUNNEL_KEY
) {
477 if (flags
& TUNNEL_CSUM
&&
478 !(skb_shinfo(skb
)->gso_type
&
479 (SKB_GSO_GRE
| SKB_GSO_GRE_CSUM
))) {
481 *(__sum16
*)ptr
= gre_checksum(skb
);
486 static void __gre_xmit(struct sk_buff
*skb
, struct net_device
*dev
,
487 const struct iphdr
*tnl_params
,
490 struct ip_tunnel
*tunnel
= netdev_priv(dev
);
492 if (tunnel
->parms
.o_flags
& TUNNEL_SEQ
)
495 /* Push GRE header. */
496 build_header(skb
, tunnel
->tun_hlen
, tunnel
->parms
.o_flags
,
497 proto
, tunnel
->parms
.o_key
, htonl(tunnel
->o_seqno
));
499 skb_set_inner_protocol(skb
, proto
);
500 ip_tunnel_xmit(skb
, dev
, tnl_params
, tnl_params
->protocol
);
503 static struct sk_buff
*gre_handle_offloads(struct sk_buff
*skb
,
506 return iptunnel_handle_offloads(skb
, csum
? SKB_GSO_GRE_CSUM
: SKB_GSO_GRE
);
509 static struct rtable
*gre_get_rt(struct sk_buff
*skb
,
510 struct net_device
*dev
,
512 const struct ip_tunnel_key
*key
)
514 struct net
*net
= dev_net(dev
);
516 memset(fl
, 0, sizeof(*fl
));
517 fl
->daddr
= key
->u
.ipv4
.dst
;
518 fl
->saddr
= key
->u
.ipv4
.src
;
519 fl
->flowi4_tos
= RT_TOS(key
->tos
);
520 fl
->flowi4_mark
= skb
->mark
;
521 fl
->flowi4_proto
= IPPROTO_GRE
;
523 return ip_route_output_key(net
, fl
);
526 static void gre_fb_xmit(struct sk_buff
*skb
, struct net_device
*dev
)
528 struct ip_tunnel_info
*tun_info
;
529 const struct ip_tunnel_key
*key
;
530 struct rtable
*rt
= NULL
;
538 tun_info
= skb_tunnel_info(skb
);
539 if (unlikely(!tun_info
|| !(tun_info
->mode
& IP_TUNNEL_INFO_TX
) ||
540 ip_tunnel_info_af(tun_info
) != AF_INET
))
543 key
= &tun_info
->key
;
544 use_cache
= ip_tunnel_dst_cache_usable(skb
, tun_info
);
546 rt
= dst_cache_get_ip4(&tun_info
->dst_cache
, &fl
.saddr
);
548 rt
= gre_get_rt(skb
, dev
, &fl
, key
);
552 dst_cache_set_ip4(&tun_info
->dst_cache
, &rt
->dst
,
556 tunnel_hlen
= ip_gre_calc_hlen(key
->tun_flags
);
558 min_headroom
= LL_RESERVED_SPACE(rt
->dst
.dev
) + rt
->dst
.header_len
559 + tunnel_hlen
+ sizeof(struct iphdr
);
560 if (skb_headroom(skb
) < min_headroom
|| skb_header_cloned(skb
)) {
561 int head_delta
= SKB_DATA_ALIGN(min_headroom
-
564 err
= pskb_expand_head(skb
, max_t(int, head_delta
, 0),
570 /* Push Tunnel header. */
571 skb
= gre_handle_offloads(skb
, !!(tun_info
->key
.tun_flags
& TUNNEL_CSUM
));
577 flags
= tun_info
->key
.tun_flags
& (TUNNEL_CSUM
| TUNNEL_KEY
);
578 build_header(skb
, tunnel_hlen
, flags
, htons(ETH_P_TEB
),
579 tunnel_id_to_key(tun_info
->key
.tun_id
), 0);
581 df
= key
->tun_flags
& TUNNEL_DONT_FRAGMENT
? htons(IP_DF
) : 0;
583 iptunnel_xmit(skb
->sk
, rt
, skb
, fl
.saddr
, key
->u
.ipv4
.dst
, IPPROTO_GRE
,
584 key
->tos
, key
->ttl
, df
, false);
591 dev
->stats
.tx_dropped
++;
594 static int gre_fill_metadata_dst(struct net_device
*dev
, struct sk_buff
*skb
)
596 struct ip_tunnel_info
*info
= skb_tunnel_info(skb
);
600 if (ip_tunnel_info_af(info
) != AF_INET
)
603 rt
= gre_get_rt(skb
, dev
, &fl4
, &info
->key
);
608 info
->key
.u
.ipv4
.src
= fl4
.saddr
;
612 static netdev_tx_t
ipgre_xmit(struct sk_buff
*skb
,
613 struct net_device
*dev
)
615 struct ip_tunnel
*tunnel
= netdev_priv(dev
);
616 const struct iphdr
*tnl_params
;
618 if (tunnel
->collect_md
) {
619 gre_fb_xmit(skb
, dev
);
623 if (dev
->header_ops
) {
624 /* Need space for new headers */
625 if (skb_cow_head(skb
, dev
->needed_headroom
-
626 (tunnel
->hlen
+ sizeof(struct iphdr
))))
629 tnl_params
= (const struct iphdr
*)skb
->data
;
631 /* Pull skb since ip_tunnel_xmit() needs skb->data pointing
634 skb_pull(skb
, tunnel
->hlen
+ sizeof(struct iphdr
));
635 skb_reset_mac_header(skb
);
637 if (skb_cow_head(skb
, dev
->needed_headroom
))
640 tnl_params
= &tunnel
->parms
.iph
;
643 skb
= gre_handle_offloads(skb
, !!(tunnel
->parms
.o_flags
&TUNNEL_CSUM
));
647 __gre_xmit(skb
, dev
, tnl_params
, skb
->protocol
);
653 dev
->stats
.tx_dropped
++;
657 static netdev_tx_t
gre_tap_xmit(struct sk_buff
*skb
,
658 struct net_device
*dev
)
660 struct ip_tunnel
*tunnel
= netdev_priv(dev
);
662 if (tunnel
->collect_md
) {
663 gre_fb_xmit(skb
, dev
);
667 skb
= gre_handle_offloads(skb
, !!(tunnel
->parms
.o_flags
&TUNNEL_CSUM
));
671 if (skb_cow_head(skb
, dev
->needed_headroom
))
674 __gre_xmit(skb
, dev
, &tunnel
->parms
.iph
, htons(ETH_P_TEB
));
680 dev
->stats
.tx_dropped
++;
684 static int ipgre_tunnel_ioctl(struct net_device
*dev
,
685 struct ifreq
*ifr
, int cmd
)
688 struct ip_tunnel_parm p
;
690 if (copy_from_user(&p
, ifr
->ifr_ifru
.ifru_data
, sizeof(p
)))
692 if (cmd
== SIOCADDTUNNEL
|| cmd
== SIOCCHGTUNNEL
) {
693 if (p
.iph
.version
!= 4 || p
.iph
.protocol
!= IPPROTO_GRE
||
694 p
.iph
.ihl
!= 5 || (p
.iph
.frag_off
&htons(~IP_DF
)) ||
695 ((p
.i_flags
|p
.o_flags
)&(GRE_VERSION
|GRE_ROUTING
)))
698 p
.i_flags
= gre_flags_to_tnl_flags(p
.i_flags
);
699 p
.o_flags
= gre_flags_to_tnl_flags(p
.o_flags
);
701 err
= ip_tunnel_ioctl(dev
, &p
, cmd
);
705 p
.i_flags
= tnl_flags_to_gre_flags(p
.i_flags
);
706 p
.o_flags
= tnl_flags_to_gre_flags(p
.o_flags
);
708 if (copy_to_user(ifr
->ifr_ifru
.ifru_data
, &p
, sizeof(p
)))
713 /* Nice toy. Unfortunately, useless in real life :-)
714 It allows to construct virtual multiprotocol broadcast "LAN"
715 over the Internet, provided multicast routing is tuned.
718 I have no idea was this bicycle invented before me,
719 so that I had to set ARPHRD_IPGRE to a random value.
720 I have an impression, that Cisco could make something similar,
721 but this feature is apparently missing in IOS<=11.2(8).
723 I set up 10.66.66/24 and fec0:6666:6666::0/96 as virtual networks
724 with broadcast 224.66.66.66. If you have access to mbone, play with me :-)
726 ping -t 255 224.66.66.66
728 If nobody answers, mbone does not work.
730 ip tunnel add Universe mode gre remote 224.66.66.66 local <Your_real_addr> ttl 255
731 ip addr add 10.66.66.<somewhat>/24 dev Universe
733 ifconfig Universe add fe80::<Your_real_addr>/10
734 ifconfig Universe add fec0:6666:6666::<Your_real_addr>/96
737 ftp fec0:6666:6666::193.233.7.65
740 static int ipgre_header(struct sk_buff
*skb
, struct net_device
*dev
,
742 const void *daddr
, const void *saddr
, unsigned int len
)
744 struct ip_tunnel
*t
= netdev_priv(dev
);
746 struct gre_base_hdr
*greh
;
748 iph
= (struct iphdr
*)skb_push(skb
, t
->hlen
+ sizeof(*iph
));
749 greh
= (struct gre_base_hdr
*)(iph
+1);
750 greh
->flags
= tnl_flags_to_gre_flags(t
->parms
.o_flags
);
751 greh
->protocol
= htons(type
);
753 memcpy(iph
, &t
->parms
.iph
, sizeof(struct iphdr
));
755 /* Set the source hardware address. */
757 memcpy(&iph
->saddr
, saddr
, 4);
759 memcpy(&iph
->daddr
, daddr
, 4);
761 return t
->hlen
+ sizeof(*iph
);
763 return -(t
->hlen
+ sizeof(*iph
));
766 static int ipgre_header_parse(const struct sk_buff
*skb
, unsigned char *haddr
)
768 const struct iphdr
*iph
= (const struct iphdr
*) skb_mac_header(skb
);
769 memcpy(haddr
, &iph
->saddr
, 4);
773 static const struct header_ops ipgre_header_ops
= {
774 .create
= ipgre_header
,
775 .parse
= ipgre_header_parse
,
778 #ifdef CONFIG_NET_IPGRE_BROADCAST
779 static int ipgre_open(struct net_device
*dev
)
781 struct ip_tunnel
*t
= netdev_priv(dev
);
783 if (ipv4_is_multicast(t
->parms
.iph
.daddr
)) {
787 rt
= ip_route_output_gre(t
->net
, &fl4
,
791 RT_TOS(t
->parms
.iph
.tos
),
794 return -EADDRNOTAVAIL
;
797 if (!__in_dev_get_rtnl(dev
))
798 return -EADDRNOTAVAIL
;
799 t
->mlink
= dev
->ifindex
;
800 ip_mc_inc_group(__in_dev_get_rtnl(dev
), t
->parms
.iph
.daddr
);
805 static int ipgre_close(struct net_device
*dev
)
807 struct ip_tunnel
*t
= netdev_priv(dev
);
809 if (ipv4_is_multicast(t
->parms
.iph
.daddr
) && t
->mlink
) {
810 struct in_device
*in_dev
;
811 in_dev
= inetdev_by_index(t
->net
, t
->mlink
);
813 ip_mc_dec_group(in_dev
, t
->parms
.iph
.daddr
);
819 static const struct net_device_ops ipgre_netdev_ops
= {
820 .ndo_init
= ipgre_tunnel_init
,
821 .ndo_uninit
= ip_tunnel_uninit
,
822 #ifdef CONFIG_NET_IPGRE_BROADCAST
823 .ndo_open
= ipgre_open
,
824 .ndo_stop
= ipgre_close
,
826 .ndo_start_xmit
= ipgre_xmit
,
827 .ndo_do_ioctl
= ipgre_tunnel_ioctl
,
828 .ndo_change_mtu
= ip_tunnel_change_mtu
,
829 .ndo_get_stats64
= ip_tunnel_get_stats64
,
830 .ndo_get_iflink
= ip_tunnel_get_iflink
,
833 #define GRE_FEATURES (NETIF_F_SG | \
838 static void ipgre_tunnel_setup(struct net_device
*dev
)
840 dev
->netdev_ops
= &ipgre_netdev_ops
;
841 dev
->type
= ARPHRD_IPGRE
;
842 ip_tunnel_setup(dev
, ipgre_net_id
);
845 static void __gre_tunnel_init(struct net_device
*dev
)
847 struct ip_tunnel
*tunnel
;
850 tunnel
= netdev_priv(dev
);
851 tunnel
->tun_hlen
= ip_gre_calc_hlen(tunnel
->parms
.o_flags
);
852 tunnel
->parms
.iph
.protocol
= IPPROTO_GRE
;
854 tunnel
->hlen
= tunnel
->tun_hlen
+ tunnel
->encap_hlen
;
856 t_hlen
= tunnel
->hlen
+ sizeof(struct iphdr
);
858 dev
->needed_headroom
= LL_MAX_HEADER
+ t_hlen
+ 4;
859 dev
->mtu
= ETH_DATA_LEN
- t_hlen
- 4;
861 dev
->features
|= GRE_FEATURES
;
862 dev
->hw_features
|= GRE_FEATURES
;
864 if (!(tunnel
->parms
.o_flags
& TUNNEL_SEQ
)) {
865 /* TCP offload with GRE SEQ is not supported. */
866 dev
->features
|= NETIF_F_GSO_SOFTWARE
;
867 dev
->hw_features
|= NETIF_F_GSO_SOFTWARE
;
868 /* Can use a lockless transmit, unless we generate
871 dev
->features
|= NETIF_F_LLTX
;
875 static int ipgre_tunnel_init(struct net_device
*dev
)
877 struct ip_tunnel
*tunnel
= netdev_priv(dev
);
878 struct iphdr
*iph
= &tunnel
->parms
.iph
;
880 __gre_tunnel_init(dev
);
882 memcpy(dev
->dev_addr
, &iph
->saddr
, 4);
883 memcpy(dev
->broadcast
, &iph
->daddr
, 4);
885 dev
->flags
= IFF_NOARP
;
890 #ifdef CONFIG_NET_IPGRE_BROADCAST
891 if (ipv4_is_multicast(iph
->daddr
)) {
894 dev
->flags
= IFF_BROADCAST
;
895 dev
->header_ops
= &ipgre_header_ops
;
899 dev
->header_ops
= &ipgre_header_ops
;
901 return ip_tunnel_init(dev
);
904 static const struct gre_protocol ipgre_protocol
= {
906 .err_handler
= gre_err
,
909 static int __net_init
ipgre_init_net(struct net
*net
)
911 return ip_tunnel_init_net(net
, ipgre_net_id
, &ipgre_link_ops
, NULL
);
914 static void __net_exit
ipgre_exit_net(struct net
*net
)
916 struct ip_tunnel_net
*itn
= net_generic(net
, ipgre_net_id
);
917 ip_tunnel_delete_net(itn
, &ipgre_link_ops
);
920 static struct pernet_operations ipgre_net_ops
= {
921 .init
= ipgre_init_net
,
922 .exit
= ipgre_exit_net
,
924 .size
= sizeof(struct ip_tunnel_net
),
927 static int ipgre_tunnel_validate(struct nlattr
*tb
[], struct nlattr
*data
[])
935 if (data
[IFLA_GRE_IFLAGS
])
936 flags
|= nla_get_be16(data
[IFLA_GRE_IFLAGS
]);
937 if (data
[IFLA_GRE_OFLAGS
])
938 flags
|= nla_get_be16(data
[IFLA_GRE_OFLAGS
]);
939 if (flags
& (GRE_VERSION
|GRE_ROUTING
))
945 static int ipgre_tap_validate(struct nlattr
*tb
[], struct nlattr
*data
[])
949 if (tb
[IFLA_ADDRESS
]) {
950 if (nla_len(tb
[IFLA_ADDRESS
]) != ETH_ALEN
)
952 if (!is_valid_ether_addr(nla_data(tb
[IFLA_ADDRESS
])))
953 return -EADDRNOTAVAIL
;
959 if (data
[IFLA_GRE_REMOTE
]) {
960 memcpy(&daddr
, nla_data(data
[IFLA_GRE_REMOTE
]), 4);
966 return ipgre_tunnel_validate(tb
, data
);
969 static void ipgre_netlink_parms(struct net_device
*dev
,
970 struct nlattr
*data
[],
972 struct ip_tunnel_parm
*parms
)
974 memset(parms
, 0, sizeof(*parms
));
976 parms
->iph
.protocol
= IPPROTO_GRE
;
981 if (data
[IFLA_GRE_LINK
])
982 parms
->link
= nla_get_u32(data
[IFLA_GRE_LINK
]);
984 if (data
[IFLA_GRE_IFLAGS
])
985 parms
->i_flags
= gre_flags_to_tnl_flags(nla_get_be16(data
[IFLA_GRE_IFLAGS
]));
987 if (data
[IFLA_GRE_OFLAGS
])
988 parms
->o_flags
= gre_flags_to_tnl_flags(nla_get_be16(data
[IFLA_GRE_OFLAGS
]));
990 if (data
[IFLA_GRE_IKEY
])
991 parms
->i_key
= nla_get_be32(data
[IFLA_GRE_IKEY
]);
993 if (data
[IFLA_GRE_OKEY
])
994 parms
->o_key
= nla_get_be32(data
[IFLA_GRE_OKEY
]);
996 if (data
[IFLA_GRE_LOCAL
])
997 parms
->iph
.saddr
= nla_get_in_addr(data
[IFLA_GRE_LOCAL
]);
999 if (data
[IFLA_GRE_REMOTE
])
1000 parms
->iph
.daddr
= nla_get_in_addr(data
[IFLA_GRE_REMOTE
]);
1002 if (data
[IFLA_GRE_TTL
])
1003 parms
->iph
.ttl
= nla_get_u8(data
[IFLA_GRE_TTL
]);
1005 if (data
[IFLA_GRE_TOS
])
1006 parms
->iph
.tos
= nla_get_u8(data
[IFLA_GRE_TOS
]);
1008 if (!data
[IFLA_GRE_PMTUDISC
] || nla_get_u8(data
[IFLA_GRE_PMTUDISC
]))
1009 parms
->iph
.frag_off
= htons(IP_DF
);
1011 if (data
[IFLA_GRE_COLLECT_METADATA
]) {
1012 struct ip_tunnel
*t
= netdev_priv(dev
);
1014 t
->collect_md
= true;
1018 /* This function returns true when ENCAP attributes are present in the nl msg */
1019 static bool ipgre_netlink_encap_parms(struct nlattr
*data
[],
1020 struct ip_tunnel_encap
*ipencap
)
1024 memset(ipencap
, 0, sizeof(*ipencap
));
1029 if (data
[IFLA_GRE_ENCAP_TYPE
]) {
1031 ipencap
->type
= nla_get_u16(data
[IFLA_GRE_ENCAP_TYPE
]);
1034 if (data
[IFLA_GRE_ENCAP_FLAGS
]) {
1036 ipencap
->flags
= nla_get_u16(data
[IFLA_GRE_ENCAP_FLAGS
]);
1039 if (data
[IFLA_GRE_ENCAP_SPORT
]) {
1041 ipencap
->sport
= nla_get_be16(data
[IFLA_GRE_ENCAP_SPORT
]);
1044 if (data
[IFLA_GRE_ENCAP_DPORT
]) {
1046 ipencap
->dport
= nla_get_be16(data
[IFLA_GRE_ENCAP_DPORT
]);
1052 static int gre_tap_init(struct net_device
*dev
)
1054 __gre_tunnel_init(dev
);
1055 dev
->priv_flags
|= IFF_LIVE_ADDR_CHANGE
;
1057 return ip_tunnel_init(dev
);
1060 static const struct net_device_ops gre_tap_netdev_ops
= {
1061 .ndo_init
= gre_tap_init
,
1062 .ndo_uninit
= ip_tunnel_uninit
,
1063 .ndo_start_xmit
= gre_tap_xmit
,
1064 .ndo_set_mac_address
= eth_mac_addr
,
1065 .ndo_validate_addr
= eth_validate_addr
,
1066 .ndo_change_mtu
= ip_tunnel_change_mtu
,
1067 .ndo_get_stats64
= ip_tunnel_get_stats64
,
1068 .ndo_get_iflink
= ip_tunnel_get_iflink
,
1069 .ndo_fill_metadata_dst
= gre_fill_metadata_dst
,
1072 static void ipgre_tap_setup(struct net_device
*dev
)
1075 dev
->netdev_ops
= &gre_tap_netdev_ops
;
1076 dev
->priv_flags
&= ~IFF_TX_SKB_SHARING
;
1077 dev
->priv_flags
|= IFF_LIVE_ADDR_CHANGE
;
1078 ip_tunnel_setup(dev
, gre_tap_net_id
);
1081 static int ipgre_newlink(struct net
*src_net
, struct net_device
*dev
,
1082 struct nlattr
*tb
[], struct nlattr
*data
[])
1084 struct ip_tunnel_parm p
;
1085 struct ip_tunnel_encap ipencap
;
1087 if (ipgre_netlink_encap_parms(data
, &ipencap
)) {
1088 struct ip_tunnel
*t
= netdev_priv(dev
);
1089 int err
= ip_tunnel_encap_setup(t
, &ipencap
);
1095 ipgre_netlink_parms(dev
, data
, tb
, &p
);
1096 return ip_tunnel_newlink(dev
, tb
, &p
);
1099 static int ipgre_changelink(struct net_device
*dev
, struct nlattr
*tb
[],
1100 struct nlattr
*data
[])
1102 struct ip_tunnel_parm p
;
1103 struct ip_tunnel_encap ipencap
;
1105 if (ipgre_netlink_encap_parms(data
, &ipencap
)) {
1106 struct ip_tunnel
*t
= netdev_priv(dev
);
1107 int err
= ip_tunnel_encap_setup(t
, &ipencap
);
1113 ipgre_netlink_parms(dev
, data
, tb
, &p
);
1114 return ip_tunnel_changelink(dev
, tb
, &p
);
1117 static size_t ipgre_get_size(const struct net_device
*dev
)
1122 /* IFLA_GRE_IFLAGS */
1124 /* IFLA_GRE_OFLAGS */
1130 /* IFLA_GRE_LOCAL */
1132 /* IFLA_GRE_REMOTE */
1138 /* IFLA_GRE_PMTUDISC */
1140 /* IFLA_GRE_ENCAP_TYPE */
1142 /* IFLA_GRE_ENCAP_FLAGS */
1144 /* IFLA_GRE_ENCAP_SPORT */
1146 /* IFLA_GRE_ENCAP_DPORT */
1148 /* IFLA_GRE_COLLECT_METADATA */
1153 static int ipgre_fill_info(struct sk_buff
*skb
, const struct net_device
*dev
)
1155 struct ip_tunnel
*t
= netdev_priv(dev
);
1156 struct ip_tunnel_parm
*p
= &t
->parms
;
1158 if (nla_put_u32(skb
, IFLA_GRE_LINK
, p
->link
) ||
1159 nla_put_be16(skb
, IFLA_GRE_IFLAGS
, tnl_flags_to_gre_flags(p
->i_flags
)) ||
1160 nla_put_be16(skb
, IFLA_GRE_OFLAGS
, tnl_flags_to_gre_flags(p
->o_flags
)) ||
1161 nla_put_be32(skb
, IFLA_GRE_IKEY
, p
->i_key
) ||
1162 nla_put_be32(skb
, IFLA_GRE_OKEY
, p
->o_key
) ||
1163 nla_put_in_addr(skb
, IFLA_GRE_LOCAL
, p
->iph
.saddr
) ||
1164 nla_put_in_addr(skb
, IFLA_GRE_REMOTE
, p
->iph
.daddr
) ||
1165 nla_put_u8(skb
, IFLA_GRE_TTL
, p
->iph
.ttl
) ||
1166 nla_put_u8(skb
, IFLA_GRE_TOS
, p
->iph
.tos
) ||
1167 nla_put_u8(skb
, IFLA_GRE_PMTUDISC
,
1168 !!(p
->iph
.frag_off
& htons(IP_DF
))))
1169 goto nla_put_failure
;
1171 if (nla_put_u16(skb
, IFLA_GRE_ENCAP_TYPE
,
1173 nla_put_be16(skb
, IFLA_GRE_ENCAP_SPORT
,
1175 nla_put_be16(skb
, IFLA_GRE_ENCAP_DPORT
,
1177 nla_put_u16(skb
, IFLA_GRE_ENCAP_FLAGS
,
1179 goto nla_put_failure
;
1181 if (t
->collect_md
) {
1182 if (nla_put_flag(skb
, IFLA_GRE_COLLECT_METADATA
))
1183 goto nla_put_failure
;
1192 static const struct nla_policy ipgre_policy
[IFLA_GRE_MAX
+ 1] = {
1193 [IFLA_GRE_LINK
] = { .type
= NLA_U32
},
1194 [IFLA_GRE_IFLAGS
] = { .type
= NLA_U16
},
1195 [IFLA_GRE_OFLAGS
] = { .type
= NLA_U16
},
1196 [IFLA_GRE_IKEY
] = { .type
= NLA_U32
},
1197 [IFLA_GRE_OKEY
] = { .type
= NLA_U32
},
1198 [IFLA_GRE_LOCAL
] = { .len
= FIELD_SIZEOF(struct iphdr
, saddr
) },
1199 [IFLA_GRE_REMOTE
] = { .len
= FIELD_SIZEOF(struct iphdr
, daddr
) },
1200 [IFLA_GRE_TTL
] = { .type
= NLA_U8
},
1201 [IFLA_GRE_TOS
] = { .type
= NLA_U8
},
1202 [IFLA_GRE_PMTUDISC
] = { .type
= NLA_U8
},
1203 [IFLA_GRE_ENCAP_TYPE
] = { .type
= NLA_U16
},
1204 [IFLA_GRE_ENCAP_FLAGS
] = { .type
= NLA_U16
},
1205 [IFLA_GRE_ENCAP_SPORT
] = { .type
= NLA_U16
},
1206 [IFLA_GRE_ENCAP_DPORT
] = { .type
= NLA_U16
},
1207 [IFLA_GRE_COLLECT_METADATA
] = { .type
= NLA_FLAG
},
1210 static struct rtnl_link_ops ipgre_link_ops __read_mostly
= {
1212 .maxtype
= IFLA_GRE_MAX
,
1213 .policy
= ipgre_policy
,
1214 .priv_size
= sizeof(struct ip_tunnel
),
1215 .setup
= ipgre_tunnel_setup
,
1216 .validate
= ipgre_tunnel_validate
,
1217 .newlink
= ipgre_newlink
,
1218 .changelink
= ipgre_changelink
,
1219 .dellink
= ip_tunnel_dellink
,
1220 .get_size
= ipgre_get_size
,
1221 .fill_info
= ipgre_fill_info
,
1222 .get_link_net
= ip_tunnel_get_link_net
,
1225 static struct rtnl_link_ops ipgre_tap_ops __read_mostly
= {
1227 .maxtype
= IFLA_GRE_MAX
,
1228 .policy
= ipgre_policy
,
1229 .priv_size
= sizeof(struct ip_tunnel
),
1230 .setup
= ipgre_tap_setup
,
1231 .validate
= ipgre_tap_validate
,
1232 .newlink
= ipgre_newlink
,
1233 .changelink
= ipgre_changelink
,
1234 .dellink
= ip_tunnel_dellink
,
1235 .get_size
= ipgre_get_size
,
1236 .fill_info
= ipgre_fill_info
,
1237 .get_link_net
= ip_tunnel_get_link_net
,
1240 struct net_device
*gretap_fb_dev_create(struct net
*net
, const char *name
,
1241 u8 name_assign_type
)
1243 struct nlattr
*tb
[IFLA_MAX
+ 1];
1244 struct net_device
*dev
;
1245 struct ip_tunnel
*t
;
1248 memset(&tb
, 0, sizeof(tb
));
1250 dev
= rtnl_create_link(net
, name
, name_assign_type
,
1251 &ipgre_tap_ops
, tb
);
1255 /* Configure flow based GRE device. */
1256 t
= netdev_priv(dev
);
1257 t
->collect_md
= true;
1259 err
= ipgre_newlink(net
, dev
, tb
, NULL
);
1263 /* openvswitch users expect packet sizes to be unrestricted,
1264 * so set the largest MTU we can.
1266 err
= __ip_tunnel_change_mtu(dev
, IP_MAX_MTU
, false);
1273 return ERR_PTR(err
);
1275 EXPORT_SYMBOL_GPL(gretap_fb_dev_create
);
1277 static int __net_init
ipgre_tap_init_net(struct net
*net
)
1279 return ip_tunnel_init_net(net
, gre_tap_net_id
, &ipgre_tap_ops
, "gretap0");
1282 static void __net_exit
ipgre_tap_exit_net(struct net
*net
)
1284 struct ip_tunnel_net
*itn
= net_generic(net
, gre_tap_net_id
);
1285 ip_tunnel_delete_net(itn
, &ipgre_tap_ops
);
1288 static struct pernet_operations ipgre_tap_net_ops
= {
1289 .init
= ipgre_tap_init_net
,
1290 .exit
= ipgre_tap_exit_net
,
1291 .id
= &gre_tap_net_id
,
1292 .size
= sizeof(struct ip_tunnel_net
),
1295 static int __init
ipgre_init(void)
1299 pr_info("GRE over IPv4 tunneling driver\n");
1301 err
= register_pernet_device(&ipgre_net_ops
);
1305 err
= register_pernet_device(&ipgre_tap_net_ops
);
1307 goto pnet_tap_faied
;
1309 err
= gre_add_protocol(&ipgre_protocol
, GREPROTO_CISCO
);
1311 pr_info("%s: can't add protocol\n", __func__
);
1312 goto add_proto_failed
;
1315 err
= rtnl_link_register(&ipgre_link_ops
);
1317 goto rtnl_link_failed
;
1319 err
= rtnl_link_register(&ipgre_tap_ops
);
1321 goto tap_ops_failed
;
1326 rtnl_link_unregister(&ipgre_link_ops
);
1328 gre_del_protocol(&ipgre_protocol
, GREPROTO_CISCO
);
1330 unregister_pernet_device(&ipgre_tap_net_ops
);
1332 unregister_pernet_device(&ipgre_net_ops
);
1336 static void __exit
ipgre_fini(void)
1338 rtnl_link_unregister(&ipgre_tap_ops
);
1339 rtnl_link_unregister(&ipgre_link_ops
);
1340 gre_del_protocol(&ipgre_protocol
, GREPROTO_CISCO
);
1341 unregister_pernet_device(&ipgre_tap_net_ops
);
1342 unregister_pernet_device(&ipgre_net_ops
);
1345 module_init(ipgre_init
);
1346 module_exit(ipgre_fini
);
1347 MODULE_LICENSE("GPL");
1348 MODULE_ALIAS_RTNL_LINK("gre");
1349 MODULE_ALIAS_RTNL_LINK("gretap");
1350 MODULE_ALIAS_NETDEV("gre0");
1351 MODULE_ALIAS_NETDEV("gretap0");