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5d9c5a3292
Now that we always zero the IPCB->opts in ip_rcv, it is no longer necessary to do so before calling netif_rx for tunneled packets. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
1306 lines
31 KiB
C
1306 lines
31 KiB
C
/*
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* Linux NET3: GRE over IP protocol decoder.
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*
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* Authors: Alexey Kuznetsov (kuznet@ms2.inr.ac.ru)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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*/
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#include <linux/capability.h>
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#include <linux/module.h>
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#include <linux/types.h>
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#include <linux/sched.h>
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#include <linux/kernel.h>
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#include <asm/uaccess.h>
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#include <linux/skbuff.h>
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#include <linux/netdevice.h>
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#include <linux/in.h>
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#include <linux/tcp.h>
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#include <linux/udp.h>
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#include <linux/if_arp.h>
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#include <linux/mroute.h>
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#include <linux/init.h>
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#include <linux/in6.h>
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#include <linux/inetdevice.h>
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#include <linux/igmp.h>
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#include <linux/netfilter_ipv4.h>
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#include <linux/if_ether.h>
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#include <net/sock.h>
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#include <net/ip.h>
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#include <net/icmp.h>
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#include <net/protocol.h>
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#include <net/ipip.h>
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#include <net/arp.h>
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#include <net/checksum.h>
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#include <net/dsfield.h>
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#include <net/inet_ecn.h>
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#include <net/xfrm.h>
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#ifdef CONFIG_IPV6
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#include <net/ipv6.h>
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#include <net/ip6_fib.h>
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#include <net/ip6_route.h>
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#endif
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/*
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Problems & solutions
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--------------------
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1. The most important issue is detecting local dead loops.
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They would cause complete host lockup in transmit, which
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would be "resolved" by stack overflow or, if queueing is enabled,
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with infinite looping in net_bh.
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We cannot track such dead loops during route installation,
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it is infeasible task. The most general solutions would be
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to keep skb->encapsulation counter (sort of local ttl),
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and silently drop packet when it expires. It is the best
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solution, but it supposes maintaing new variable in ALL
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skb, even if no tunneling is used.
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Current solution: t->recursion lock breaks dead loops. It looks
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like dev->tbusy flag, but I preferred new variable, because
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the semantics is different. One day, when hard_start_xmit
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will be multithreaded we will have to use skb->encapsulation.
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2. Networking dead loops would not kill routers, but would really
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kill network. IP hop limit plays role of "t->recursion" in this case,
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if we copy it from packet being encapsulated to upper header.
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It is very good solution, but it introduces two problems:
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- Routing protocols, using packets with ttl=1 (OSPF, RIP2),
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do not work over tunnels.
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- traceroute does not work. I planned to relay ICMP from tunnel,
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so that this problem would be solved and traceroute output
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would even more informative. This idea appeared to be wrong:
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only Linux complies to rfc1812 now (yes, guys, Linux is the only
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true router now :-)), all routers (at least, in neighbourhood of mine)
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return only 8 bytes of payload. It is the end.
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Hence, if we want that OSPF worked or traceroute said something reasonable,
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we should search for another solution.
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One of them is to parse packet trying to detect inner encapsulation
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made by our node. It is difficult or even impossible, especially,
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taking into account fragmentation. TO be short, tt is not solution at all.
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Current solution: The solution was UNEXPECTEDLY SIMPLE.
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We force DF flag on tunnels with preconfigured hop limit,
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that is ALL. :-) Well, it does not remove the problem completely,
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but exponential growth of network traffic is changed to linear
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(branches, that exceed pmtu are pruned) and tunnel mtu
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fastly degrades to value <68, where looping stops.
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Yes, it is not good if there exists a router in the loop,
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which does not force DF, even when encapsulating packets have DF set.
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But it is not our problem! Nobody could accuse us, we made
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all that we could make. Even if it is your gated who injected
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fatal route to network, even if it were you who configured
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fatal static route: you are innocent. :-)
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3. Really, ipv4/ipip.c, ipv4/ip_gre.c and ipv6/sit.c contain
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practically identical code. It would be good to glue them
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together, but it is not very evident, how to make them modular.
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sit is integral part of IPv6, ipip and gre are naturally modular.
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We could extract common parts (hash table, ioctl etc)
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to a separate module (ip_tunnel.c).
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Alexey Kuznetsov.
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*/
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static int ipgre_tunnel_init(struct net_device *dev);
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static void ipgre_tunnel_setup(struct net_device *dev);
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/* Fallback tunnel: no source, no destination, no key, no options */
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static int ipgre_fb_tunnel_init(struct net_device *dev);
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static struct net_device *ipgre_fb_tunnel_dev;
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/* Tunnel hash table */
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/*
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4 hash tables:
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3: (remote,local)
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2: (remote,*)
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1: (*,local)
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0: (*,*)
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We require exact key match i.e. if a key is present in packet
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it will match only tunnel with the same key; if it is not present,
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it will match only keyless tunnel.
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All keysless packets, if not matched configured keyless tunnels
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will match fallback tunnel.
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*/
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#define HASH_SIZE 16
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#define HASH(addr) ((addr^(addr>>4))&0xF)
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static struct ip_tunnel *tunnels[4][HASH_SIZE];
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#define tunnels_r_l (tunnels[3])
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#define tunnels_r (tunnels[2])
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#define tunnels_l (tunnels[1])
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#define tunnels_wc (tunnels[0])
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static DEFINE_RWLOCK(ipgre_lock);
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/* Given src, dst and key, find appropriate for input tunnel. */
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static struct ip_tunnel * ipgre_tunnel_lookup(u32 remote, u32 local, u32 key)
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{
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unsigned h0 = HASH(remote);
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unsigned h1 = HASH(key);
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struct ip_tunnel *t;
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for (t = tunnels_r_l[h0^h1]; t; t = t->next) {
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if (local == t->parms.iph.saddr && remote == t->parms.iph.daddr) {
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if (t->parms.i_key == key && (t->dev->flags&IFF_UP))
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return t;
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}
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}
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for (t = tunnels_r[h0^h1]; t; t = t->next) {
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if (remote == t->parms.iph.daddr) {
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if (t->parms.i_key == key && (t->dev->flags&IFF_UP))
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return t;
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}
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}
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for (t = tunnels_l[h1]; t; t = t->next) {
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if (local == t->parms.iph.saddr ||
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(local == t->parms.iph.daddr && MULTICAST(local))) {
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if (t->parms.i_key == key && (t->dev->flags&IFF_UP))
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return t;
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}
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}
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for (t = tunnels_wc[h1]; t; t = t->next) {
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if (t->parms.i_key == key && (t->dev->flags&IFF_UP))
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return t;
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}
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if (ipgre_fb_tunnel_dev->flags&IFF_UP)
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return netdev_priv(ipgre_fb_tunnel_dev);
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return NULL;
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}
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static struct ip_tunnel **ipgre_bucket(struct ip_tunnel *t)
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{
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u32 remote = t->parms.iph.daddr;
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u32 local = t->parms.iph.saddr;
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u32 key = t->parms.i_key;
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unsigned h = HASH(key);
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int prio = 0;
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if (local)
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prio |= 1;
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if (remote && !MULTICAST(remote)) {
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prio |= 2;
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h ^= HASH(remote);
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}
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return &tunnels[prio][h];
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}
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static void ipgre_tunnel_link(struct ip_tunnel *t)
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{
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struct ip_tunnel **tp = ipgre_bucket(t);
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t->next = *tp;
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write_lock_bh(&ipgre_lock);
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*tp = t;
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write_unlock_bh(&ipgre_lock);
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}
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static void ipgre_tunnel_unlink(struct ip_tunnel *t)
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{
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struct ip_tunnel **tp;
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for (tp = ipgre_bucket(t); *tp; tp = &(*tp)->next) {
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if (t == *tp) {
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write_lock_bh(&ipgre_lock);
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*tp = t->next;
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write_unlock_bh(&ipgre_lock);
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break;
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}
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}
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}
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static struct ip_tunnel * ipgre_tunnel_locate(struct ip_tunnel_parm *parms, int create)
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{
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u32 remote = parms->iph.daddr;
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u32 local = parms->iph.saddr;
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u32 key = parms->i_key;
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struct ip_tunnel *t, **tp, *nt;
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struct net_device *dev;
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unsigned h = HASH(key);
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int prio = 0;
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char name[IFNAMSIZ];
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if (local)
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prio |= 1;
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if (remote && !MULTICAST(remote)) {
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prio |= 2;
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h ^= HASH(remote);
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}
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for (tp = &tunnels[prio][h]; (t = *tp) != NULL; tp = &t->next) {
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if (local == t->parms.iph.saddr && remote == t->parms.iph.daddr) {
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if (key == t->parms.i_key)
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return t;
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}
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}
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if (!create)
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return NULL;
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if (parms->name[0])
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strlcpy(name, parms->name, IFNAMSIZ);
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else {
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int i;
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for (i=1; i<100; i++) {
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sprintf(name, "gre%d", i);
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if (__dev_get_by_name(name) == NULL)
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break;
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}
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if (i==100)
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goto failed;
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}
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dev = alloc_netdev(sizeof(*t), name, ipgre_tunnel_setup);
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if (!dev)
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return NULL;
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dev->init = ipgre_tunnel_init;
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nt = netdev_priv(dev);
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nt->parms = *parms;
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if (register_netdevice(dev) < 0) {
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free_netdev(dev);
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goto failed;
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}
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dev_hold(dev);
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ipgre_tunnel_link(nt);
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return nt;
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failed:
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return NULL;
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}
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static void ipgre_tunnel_uninit(struct net_device *dev)
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{
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ipgre_tunnel_unlink(netdev_priv(dev));
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dev_put(dev);
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}
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static void ipgre_err(struct sk_buff *skb, u32 info)
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{
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#ifndef I_WISH_WORLD_WERE_PERFECT
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/* It is not :-( All the routers (except for Linux) return only
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8 bytes of packet payload. It means, that precise relaying of
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ICMP in the real Internet is absolutely infeasible.
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Moreover, Cisco "wise men" put GRE key to the third word
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in GRE header. It makes impossible maintaining even soft state for keyed
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GRE tunnels with enabled checksum. Tell them "thank you".
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Well, I wonder, rfc1812 was written by Cisco employee,
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what the hell these idiots break standrads established
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by themself???
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*/
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struct iphdr *iph = (struct iphdr*)skb->data;
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u16 *p = (u16*)(skb->data+(iph->ihl<<2));
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int grehlen = (iph->ihl<<2) + 4;
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int type = skb->h.icmph->type;
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int code = skb->h.icmph->code;
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struct ip_tunnel *t;
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u16 flags;
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flags = p[0];
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if (flags&(GRE_CSUM|GRE_KEY|GRE_SEQ|GRE_ROUTING|GRE_VERSION)) {
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if (flags&(GRE_VERSION|GRE_ROUTING))
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return;
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if (flags&GRE_KEY) {
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grehlen += 4;
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if (flags&GRE_CSUM)
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grehlen += 4;
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}
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}
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/* If only 8 bytes returned, keyed message will be dropped here */
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if (skb_headlen(skb) < grehlen)
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return;
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switch (type) {
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default:
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case ICMP_PARAMETERPROB:
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return;
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case ICMP_DEST_UNREACH:
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switch (code) {
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case ICMP_SR_FAILED:
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case ICMP_PORT_UNREACH:
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/* Impossible event. */
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return;
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case ICMP_FRAG_NEEDED:
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/* Soft state for pmtu is maintained by IP core. */
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return;
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default:
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/* All others are translated to HOST_UNREACH.
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rfc2003 contains "deep thoughts" about NET_UNREACH,
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I believe they are just ether pollution. --ANK
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*/
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break;
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}
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break;
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case ICMP_TIME_EXCEEDED:
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if (code != ICMP_EXC_TTL)
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return;
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break;
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}
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read_lock(&ipgre_lock);
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t = ipgre_tunnel_lookup(iph->daddr, iph->saddr, (flags&GRE_KEY) ? *(((u32*)p) + (grehlen>>2) - 1) : 0);
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if (t == NULL || t->parms.iph.daddr == 0 || MULTICAST(t->parms.iph.daddr))
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goto out;
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if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
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goto out;
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if (jiffies - t->err_time < IPTUNNEL_ERR_TIMEO)
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t->err_count++;
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else
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t->err_count = 1;
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t->err_time = jiffies;
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out:
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read_unlock(&ipgre_lock);
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return;
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#else
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struct iphdr *iph = (struct iphdr*)dp;
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struct iphdr *eiph;
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u16 *p = (u16*)(dp+(iph->ihl<<2));
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int type = skb->h.icmph->type;
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int code = skb->h.icmph->code;
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int rel_type = 0;
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int rel_code = 0;
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int rel_info = 0;
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u16 flags;
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int grehlen = (iph->ihl<<2) + 4;
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struct sk_buff *skb2;
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struct flowi fl;
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struct rtable *rt;
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if (p[1] != htons(ETH_P_IP))
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return;
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flags = p[0];
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if (flags&(GRE_CSUM|GRE_KEY|GRE_SEQ|GRE_ROUTING|GRE_VERSION)) {
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if (flags&(GRE_VERSION|GRE_ROUTING))
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return;
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if (flags&GRE_CSUM)
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grehlen += 4;
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if (flags&GRE_KEY)
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grehlen += 4;
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if (flags&GRE_SEQ)
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grehlen += 4;
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}
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if (len < grehlen + sizeof(struct iphdr))
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return;
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eiph = (struct iphdr*)(dp + grehlen);
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switch (type) {
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default:
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return;
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case ICMP_PARAMETERPROB:
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if (skb->h.icmph->un.gateway < (iph->ihl<<2))
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return;
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/* So... This guy found something strange INSIDE encapsulated
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packet. Well, he is fool, but what can we do ?
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*/
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rel_type = ICMP_PARAMETERPROB;
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rel_info = skb->h.icmph->un.gateway - grehlen;
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break;
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case ICMP_DEST_UNREACH:
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switch (code) {
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case ICMP_SR_FAILED:
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case ICMP_PORT_UNREACH:
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/* Impossible event. */
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return;
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case ICMP_FRAG_NEEDED:
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/* And it is the only really necessary thing :-) */
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rel_info = ntohs(skb->h.icmph->un.frag.mtu);
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if (rel_info < grehlen+68)
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return;
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rel_info -= grehlen;
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/* BSD 4.2 MORE DOES NOT EXIST IN NATURE. */
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if (rel_info > ntohs(eiph->tot_len))
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return;
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break;
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default:
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/* All others are translated to HOST_UNREACH.
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rfc2003 contains "deep thoughts" about NET_UNREACH,
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I believe, it is just ether pollution. --ANK
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*/
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rel_type = ICMP_DEST_UNREACH;
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rel_code = ICMP_HOST_UNREACH;
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break;
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}
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break;
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case ICMP_TIME_EXCEEDED:
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if (code != ICMP_EXC_TTL)
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return;
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break;
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}
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/* Prepare fake skb to feed it to icmp_send */
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skb2 = skb_clone(skb, GFP_ATOMIC);
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if (skb2 == NULL)
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return;
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dst_release(skb2->dst);
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skb2->dst = NULL;
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skb_pull(skb2, skb->data - (u8*)eiph);
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skb2->nh.raw = skb2->data;
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/* Try to guess incoming interface */
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memset(&fl, 0, sizeof(fl));
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fl.fl4_dst = eiph->saddr;
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fl.fl4_tos = RT_TOS(eiph->tos);
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fl.proto = IPPROTO_GRE;
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if (ip_route_output_key(&rt, &fl)) {
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kfree_skb(skb2);
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return;
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}
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skb2->dev = rt->u.dst.dev;
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|
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/* route "incoming" packet */
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if (rt->rt_flags&RTCF_LOCAL) {
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ip_rt_put(rt);
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rt = NULL;
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fl.fl4_dst = eiph->daddr;
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fl.fl4_src = eiph->saddr;
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fl.fl4_tos = eiph->tos;
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if (ip_route_output_key(&rt, &fl) ||
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rt->u.dst.dev->type != ARPHRD_IPGRE) {
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ip_rt_put(rt);
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kfree_skb(skb2);
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return;
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|
}
|
|
} else {
|
|
ip_rt_put(rt);
|
|
if (ip_route_input(skb2, eiph->daddr, eiph->saddr, eiph->tos, skb2->dev) ||
|
|
skb2->dst->dev->type != ARPHRD_IPGRE) {
|
|
kfree_skb(skb2);
|
|
return;
|
|
}
|
|
}
|
|
|
|
/* change mtu on this route */
|
|
if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) {
|
|
if (rel_info > dst_mtu(skb2->dst)) {
|
|
kfree_skb(skb2);
|
|
return;
|
|
}
|
|
skb2->dst->ops->update_pmtu(skb2->dst, rel_info);
|
|
rel_info = htonl(rel_info);
|
|
} else if (type == ICMP_TIME_EXCEEDED) {
|
|
struct ip_tunnel *t = netdev_priv(skb2->dev);
|
|
if (t->parms.iph.ttl) {
|
|
rel_type = ICMP_DEST_UNREACH;
|
|
rel_code = ICMP_HOST_UNREACH;
|
|
}
|
|
}
|
|
|
|
icmp_send(skb2, rel_type, rel_code, rel_info);
|
|
kfree_skb(skb2);
|
|
#endif
|
|
}
|
|
|
|
static inline void ipgre_ecn_decapsulate(struct iphdr *iph, struct sk_buff *skb)
|
|
{
|
|
if (INET_ECN_is_ce(iph->tos)) {
|
|
if (skb->protocol == htons(ETH_P_IP)) {
|
|
IP_ECN_set_ce(skb->nh.iph);
|
|
} else if (skb->protocol == htons(ETH_P_IPV6)) {
|
|
IP6_ECN_set_ce(skb->nh.ipv6h);
|
|
}
|
|
}
|
|
}
|
|
|
|
static inline u8
|
|
ipgre_ecn_encapsulate(u8 tos, struct iphdr *old_iph, struct sk_buff *skb)
|
|
{
|
|
u8 inner = 0;
|
|
if (skb->protocol == htons(ETH_P_IP))
|
|
inner = old_iph->tos;
|
|
else if (skb->protocol == htons(ETH_P_IPV6))
|
|
inner = ipv6_get_dsfield((struct ipv6hdr *)old_iph);
|
|
return INET_ECN_encapsulate(tos, inner);
|
|
}
|
|
|
|
static int ipgre_rcv(struct sk_buff *skb)
|
|
{
|
|
struct iphdr *iph;
|
|
u8 *h;
|
|
u16 flags;
|
|
u16 csum = 0;
|
|
u32 key = 0;
|
|
u32 seqno = 0;
|
|
struct ip_tunnel *tunnel;
|
|
int offset = 4;
|
|
|
|
if (!pskb_may_pull(skb, 16))
|
|
goto drop_nolock;
|
|
|
|
iph = skb->nh.iph;
|
|
h = skb->data;
|
|
flags = *(u16*)h;
|
|
|
|
if (flags&(GRE_CSUM|GRE_KEY|GRE_ROUTING|GRE_SEQ|GRE_VERSION)) {
|
|
/* - Version must be 0.
|
|
- We do not support routing headers.
|
|
*/
|
|
if (flags&(GRE_VERSION|GRE_ROUTING))
|
|
goto drop_nolock;
|
|
|
|
if (flags&GRE_CSUM) {
|
|
switch (skb->ip_summed) {
|
|
case CHECKSUM_HW:
|
|
csum = (u16)csum_fold(skb->csum);
|
|
if (!csum)
|
|
break;
|
|
/* fall through */
|
|
case CHECKSUM_NONE:
|
|
skb->csum = 0;
|
|
csum = __skb_checksum_complete(skb);
|
|
skb->ip_summed = CHECKSUM_HW;
|
|
}
|
|
offset += 4;
|
|
}
|
|
if (flags&GRE_KEY) {
|
|
key = *(u32*)(h + offset);
|
|
offset += 4;
|
|
}
|
|
if (flags&GRE_SEQ) {
|
|
seqno = ntohl(*(u32*)(h + offset));
|
|
offset += 4;
|
|
}
|
|
}
|
|
|
|
read_lock(&ipgre_lock);
|
|
if ((tunnel = ipgre_tunnel_lookup(iph->saddr, iph->daddr, key)) != NULL) {
|
|
secpath_reset(skb);
|
|
|
|
skb->protocol = *(u16*)(h + 2);
|
|
/* WCCP version 1 and 2 protocol decoding.
|
|
* - Change protocol to IP
|
|
* - When dealing with WCCPv2, Skip extra 4 bytes in GRE header
|
|
*/
|
|
if (flags == 0 &&
|
|
skb->protocol == __constant_htons(ETH_P_WCCP)) {
|
|
skb->protocol = __constant_htons(ETH_P_IP);
|
|
if ((*(h + offset) & 0xF0) != 0x40)
|
|
offset += 4;
|
|
}
|
|
|
|
skb->mac.raw = skb->nh.raw;
|
|
skb->nh.raw = __pskb_pull(skb, offset);
|
|
skb_postpull_rcsum(skb, skb->h.raw, offset);
|
|
skb->pkt_type = PACKET_HOST;
|
|
#ifdef CONFIG_NET_IPGRE_BROADCAST
|
|
if (MULTICAST(iph->daddr)) {
|
|
/* Looped back packet, drop it! */
|
|
if (((struct rtable*)skb->dst)->fl.iif == 0)
|
|
goto drop;
|
|
tunnel->stat.multicast++;
|
|
skb->pkt_type = PACKET_BROADCAST;
|
|
}
|
|
#endif
|
|
|
|
if (((flags&GRE_CSUM) && csum) ||
|
|
(!(flags&GRE_CSUM) && tunnel->parms.i_flags&GRE_CSUM)) {
|
|
tunnel->stat.rx_crc_errors++;
|
|
tunnel->stat.rx_errors++;
|
|
goto drop;
|
|
}
|
|
if (tunnel->parms.i_flags&GRE_SEQ) {
|
|
if (!(flags&GRE_SEQ) ||
|
|
(tunnel->i_seqno && (s32)(seqno - tunnel->i_seqno) < 0)) {
|
|
tunnel->stat.rx_fifo_errors++;
|
|
tunnel->stat.rx_errors++;
|
|
goto drop;
|
|
}
|
|
tunnel->i_seqno = seqno + 1;
|
|
}
|
|
tunnel->stat.rx_packets++;
|
|
tunnel->stat.rx_bytes += skb->len;
|
|
skb->dev = tunnel->dev;
|
|
dst_release(skb->dst);
|
|
skb->dst = NULL;
|
|
nf_reset(skb);
|
|
ipgre_ecn_decapsulate(iph, skb);
|
|
netif_rx(skb);
|
|
read_unlock(&ipgre_lock);
|
|
return(0);
|
|
}
|
|
icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
|
|
|
|
drop:
|
|
read_unlock(&ipgre_lock);
|
|
drop_nolock:
|
|
kfree_skb(skb);
|
|
return(0);
|
|
}
|
|
|
|
static int ipgre_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
|
|
{
|
|
struct ip_tunnel *tunnel = netdev_priv(dev);
|
|
struct net_device_stats *stats = &tunnel->stat;
|
|
struct iphdr *old_iph = skb->nh.iph;
|
|
struct iphdr *tiph;
|
|
u8 tos;
|
|
u16 df;
|
|
struct rtable *rt; /* Route to the other host */
|
|
struct net_device *tdev; /* Device to other host */
|
|
struct iphdr *iph; /* Our new IP header */
|
|
int max_headroom; /* The extra header space needed */
|
|
int gre_hlen;
|
|
u32 dst;
|
|
int mtu;
|
|
|
|
if (tunnel->recursion++) {
|
|
tunnel->stat.collisions++;
|
|
goto tx_error;
|
|
}
|
|
|
|
if (dev->hard_header) {
|
|
gre_hlen = 0;
|
|
tiph = (struct iphdr*)skb->data;
|
|
} else {
|
|
gre_hlen = tunnel->hlen;
|
|
tiph = &tunnel->parms.iph;
|
|
}
|
|
|
|
if ((dst = tiph->daddr) == 0) {
|
|
/* NBMA tunnel */
|
|
|
|
if (skb->dst == NULL) {
|
|
tunnel->stat.tx_fifo_errors++;
|
|
goto tx_error;
|
|
}
|
|
|
|
if (skb->protocol == htons(ETH_P_IP)) {
|
|
rt = (struct rtable*)skb->dst;
|
|
if ((dst = rt->rt_gateway) == 0)
|
|
goto tx_error_icmp;
|
|
}
|
|
#ifdef CONFIG_IPV6
|
|
else if (skb->protocol == htons(ETH_P_IPV6)) {
|
|
struct in6_addr *addr6;
|
|
int addr_type;
|
|
struct neighbour *neigh = skb->dst->neighbour;
|
|
|
|
if (neigh == NULL)
|
|
goto tx_error;
|
|
|
|
addr6 = (struct in6_addr*)&neigh->primary_key;
|
|
addr_type = ipv6_addr_type(addr6);
|
|
|
|
if (addr_type == IPV6_ADDR_ANY) {
|
|
addr6 = &skb->nh.ipv6h->daddr;
|
|
addr_type = ipv6_addr_type(addr6);
|
|
}
|
|
|
|
if ((addr_type & IPV6_ADDR_COMPATv4) == 0)
|
|
goto tx_error_icmp;
|
|
|
|
dst = addr6->s6_addr32[3];
|
|
}
|
|
#endif
|
|
else
|
|
goto tx_error;
|
|
}
|
|
|
|
tos = tiph->tos;
|
|
if (tos&1) {
|
|
if (skb->protocol == htons(ETH_P_IP))
|
|
tos = old_iph->tos;
|
|
tos &= ~1;
|
|
}
|
|
|
|
{
|
|
struct flowi fl = { .oif = tunnel->parms.link,
|
|
.nl_u = { .ip4_u =
|
|
{ .daddr = dst,
|
|
.saddr = tiph->saddr,
|
|
.tos = RT_TOS(tos) } },
|
|
.proto = IPPROTO_GRE };
|
|
if (ip_route_output_key(&rt, &fl)) {
|
|
tunnel->stat.tx_carrier_errors++;
|
|
goto tx_error;
|
|
}
|
|
}
|
|
tdev = rt->u.dst.dev;
|
|
|
|
if (tdev == dev) {
|
|
ip_rt_put(rt);
|
|
tunnel->stat.collisions++;
|
|
goto tx_error;
|
|
}
|
|
|
|
df = tiph->frag_off;
|
|
if (df)
|
|
mtu = dst_mtu(&rt->u.dst) - tunnel->hlen;
|
|
else
|
|
mtu = skb->dst ? dst_mtu(skb->dst) : dev->mtu;
|
|
|
|
if (skb->dst)
|
|
skb->dst->ops->update_pmtu(skb->dst, mtu);
|
|
|
|
if (skb->protocol == htons(ETH_P_IP)) {
|
|
df |= (old_iph->frag_off&htons(IP_DF));
|
|
|
|
if ((old_iph->frag_off&htons(IP_DF)) &&
|
|
mtu < ntohs(old_iph->tot_len)) {
|
|
icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, htonl(mtu));
|
|
ip_rt_put(rt);
|
|
goto tx_error;
|
|
}
|
|
}
|
|
#ifdef CONFIG_IPV6
|
|
else if (skb->protocol == htons(ETH_P_IPV6)) {
|
|
struct rt6_info *rt6 = (struct rt6_info*)skb->dst;
|
|
|
|
if (rt6 && mtu < dst_mtu(skb->dst) && mtu >= IPV6_MIN_MTU) {
|
|
if ((tunnel->parms.iph.daddr && !MULTICAST(tunnel->parms.iph.daddr)) ||
|
|
rt6->rt6i_dst.plen == 128) {
|
|
rt6->rt6i_flags |= RTF_MODIFIED;
|
|
skb->dst->metrics[RTAX_MTU-1] = mtu;
|
|
}
|
|
}
|
|
|
|
if (mtu >= IPV6_MIN_MTU && mtu < skb->len - tunnel->hlen + gre_hlen) {
|
|
icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, dev);
|
|
ip_rt_put(rt);
|
|
goto tx_error;
|
|
}
|
|
}
|
|
#endif
|
|
|
|
if (tunnel->err_count > 0) {
|
|
if (jiffies - tunnel->err_time < IPTUNNEL_ERR_TIMEO) {
|
|
tunnel->err_count--;
|
|
|
|
dst_link_failure(skb);
|
|
} else
|
|
tunnel->err_count = 0;
|
|
}
|
|
|
|
max_headroom = LL_RESERVED_SPACE(tdev) + gre_hlen;
|
|
|
|
if (skb_headroom(skb) < max_headroom || skb_cloned(skb) || skb_shared(skb)) {
|
|
struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
|
|
if (!new_skb) {
|
|
ip_rt_put(rt);
|
|
stats->tx_dropped++;
|
|
dev_kfree_skb(skb);
|
|
tunnel->recursion--;
|
|
return 0;
|
|
}
|
|
if (skb->sk)
|
|
skb_set_owner_w(new_skb, skb->sk);
|
|
dev_kfree_skb(skb);
|
|
skb = new_skb;
|
|
old_iph = skb->nh.iph;
|
|
}
|
|
|
|
skb->h.raw = skb->nh.raw;
|
|
skb->nh.raw = skb_push(skb, gre_hlen);
|
|
memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
|
|
IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED |
|
|
IPSKB_REROUTED);
|
|
dst_release(skb->dst);
|
|
skb->dst = &rt->u.dst;
|
|
|
|
/*
|
|
* Push down and install the IPIP header.
|
|
*/
|
|
|
|
iph = skb->nh.iph;
|
|
iph->version = 4;
|
|
iph->ihl = sizeof(struct iphdr) >> 2;
|
|
iph->frag_off = df;
|
|
iph->protocol = IPPROTO_GRE;
|
|
iph->tos = ipgre_ecn_encapsulate(tos, old_iph, skb);
|
|
iph->daddr = rt->rt_dst;
|
|
iph->saddr = rt->rt_src;
|
|
|
|
if ((iph->ttl = tiph->ttl) == 0) {
|
|
if (skb->protocol == htons(ETH_P_IP))
|
|
iph->ttl = old_iph->ttl;
|
|
#ifdef CONFIG_IPV6
|
|
else if (skb->protocol == htons(ETH_P_IPV6))
|
|
iph->ttl = ((struct ipv6hdr*)old_iph)->hop_limit;
|
|
#endif
|
|
else
|
|
iph->ttl = dst_metric(&rt->u.dst, RTAX_HOPLIMIT);
|
|
}
|
|
|
|
((u16*)(iph+1))[0] = tunnel->parms.o_flags;
|
|
((u16*)(iph+1))[1] = skb->protocol;
|
|
|
|
if (tunnel->parms.o_flags&(GRE_KEY|GRE_CSUM|GRE_SEQ)) {
|
|
u32 *ptr = (u32*)(((u8*)iph) + tunnel->hlen - 4);
|
|
|
|
if (tunnel->parms.o_flags&GRE_SEQ) {
|
|
++tunnel->o_seqno;
|
|
*ptr = htonl(tunnel->o_seqno);
|
|
ptr--;
|
|
}
|
|
if (tunnel->parms.o_flags&GRE_KEY) {
|
|
*ptr = tunnel->parms.o_key;
|
|
ptr--;
|
|
}
|
|
if (tunnel->parms.o_flags&GRE_CSUM) {
|
|
*ptr = 0;
|
|
*(__u16*)ptr = ip_compute_csum((void*)(iph+1), skb->len - sizeof(struct iphdr));
|
|
}
|
|
}
|
|
|
|
nf_reset(skb);
|
|
|
|
IPTUNNEL_XMIT();
|
|
tunnel->recursion--;
|
|
return 0;
|
|
|
|
tx_error_icmp:
|
|
dst_link_failure(skb);
|
|
|
|
tx_error:
|
|
stats->tx_errors++;
|
|
dev_kfree_skb(skb);
|
|
tunnel->recursion--;
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
ipgre_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd)
|
|
{
|
|
int err = 0;
|
|
struct ip_tunnel_parm p;
|
|
struct ip_tunnel *t;
|
|
|
|
switch (cmd) {
|
|
case SIOCGETTUNNEL:
|
|
t = NULL;
|
|
if (dev == ipgre_fb_tunnel_dev) {
|
|
if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
|
|
err = -EFAULT;
|
|
break;
|
|
}
|
|
t = ipgre_tunnel_locate(&p, 0);
|
|
}
|
|
if (t == NULL)
|
|
t = netdev_priv(dev);
|
|
memcpy(&p, &t->parms, sizeof(p));
|
|
if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
|
|
err = -EFAULT;
|
|
break;
|
|
|
|
case SIOCADDTUNNEL:
|
|
case SIOCCHGTUNNEL:
|
|
err = -EPERM;
|
|
if (!capable(CAP_NET_ADMIN))
|
|
goto done;
|
|
|
|
err = -EFAULT;
|
|
if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
|
|
goto done;
|
|
|
|
err = -EINVAL;
|
|
if (p.iph.version != 4 || p.iph.protocol != IPPROTO_GRE ||
|
|
p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)) ||
|
|
((p.i_flags|p.o_flags)&(GRE_VERSION|GRE_ROUTING)))
|
|
goto done;
|
|
if (p.iph.ttl)
|
|
p.iph.frag_off |= htons(IP_DF);
|
|
|
|
if (!(p.i_flags&GRE_KEY))
|
|
p.i_key = 0;
|
|
if (!(p.o_flags&GRE_KEY))
|
|
p.o_key = 0;
|
|
|
|
t = ipgre_tunnel_locate(&p, cmd == SIOCADDTUNNEL);
|
|
|
|
if (dev != ipgre_fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
|
|
if (t != NULL) {
|
|
if (t->dev != dev) {
|
|
err = -EEXIST;
|
|
break;
|
|
}
|
|
} else {
|
|
unsigned nflags=0;
|
|
|
|
t = netdev_priv(dev);
|
|
|
|
if (MULTICAST(p.iph.daddr))
|
|
nflags = IFF_BROADCAST;
|
|
else if (p.iph.daddr)
|
|
nflags = IFF_POINTOPOINT;
|
|
|
|
if ((dev->flags^nflags)&(IFF_POINTOPOINT|IFF_BROADCAST)) {
|
|
err = -EINVAL;
|
|
break;
|
|
}
|
|
ipgre_tunnel_unlink(t);
|
|
t->parms.iph.saddr = p.iph.saddr;
|
|
t->parms.iph.daddr = p.iph.daddr;
|
|
t->parms.i_key = p.i_key;
|
|
t->parms.o_key = p.o_key;
|
|
memcpy(dev->dev_addr, &p.iph.saddr, 4);
|
|
memcpy(dev->broadcast, &p.iph.daddr, 4);
|
|
ipgre_tunnel_link(t);
|
|
netdev_state_change(dev);
|
|
}
|
|
}
|
|
|
|
if (t) {
|
|
err = 0;
|
|
if (cmd == SIOCCHGTUNNEL) {
|
|
t->parms.iph.ttl = p.iph.ttl;
|
|
t->parms.iph.tos = p.iph.tos;
|
|
t->parms.iph.frag_off = p.iph.frag_off;
|
|
}
|
|
if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p)))
|
|
err = -EFAULT;
|
|
} else
|
|
err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
|
|
break;
|
|
|
|
case SIOCDELTUNNEL:
|
|
err = -EPERM;
|
|
if (!capable(CAP_NET_ADMIN))
|
|
goto done;
|
|
|
|
if (dev == ipgre_fb_tunnel_dev) {
|
|
err = -EFAULT;
|
|
if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
|
|
goto done;
|
|
err = -ENOENT;
|
|
if ((t = ipgre_tunnel_locate(&p, 0)) == NULL)
|
|
goto done;
|
|
err = -EPERM;
|
|
if (t == netdev_priv(ipgre_fb_tunnel_dev))
|
|
goto done;
|
|
dev = t->dev;
|
|
}
|
|
err = unregister_netdevice(dev);
|
|
break;
|
|
|
|
default:
|
|
err = -EINVAL;
|
|
}
|
|
|
|
done:
|
|
return err;
|
|
}
|
|
|
|
static struct net_device_stats *ipgre_tunnel_get_stats(struct net_device *dev)
|
|
{
|
|
return &(((struct ip_tunnel*)netdev_priv(dev))->stat);
|
|
}
|
|
|
|
static int ipgre_tunnel_change_mtu(struct net_device *dev, int new_mtu)
|
|
{
|
|
struct ip_tunnel *tunnel = netdev_priv(dev);
|
|
if (new_mtu < 68 || new_mtu > 0xFFF8 - tunnel->hlen)
|
|
return -EINVAL;
|
|
dev->mtu = new_mtu;
|
|
return 0;
|
|
}
|
|
|
|
#ifdef CONFIG_NET_IPGRE_BROADCAST
|
|
/* Nice toy. Unfortunately, useless in real life :-)
|
|
It allows to construct virtual multiprotocol broadcast "LAN"
|
|
over the Internet, provided multicast routing is tuned.
|
|
|
|
|
|
I have no idea was this bicycle invented before me,
|
|
so that I had to set ARPHRD_IPGRE to a random value.
|
|
I have an impression, that Cisco could make something similar,
|
|
but this feature is apparently missing in IOS<=11.2(8).
|
|
|
|
I set up 10.66.66/24 and fec0:6666:6666::0/96 as virtual networks
|
|
with broadcast 224.66.66.66. If you have access to mbone, play with me :-)
|
|
|
|
ping -t 255 224.66.66.66
|
|
|
|
If nobody answers, mbone does not work.
|
|
|
|
ip tunnel add Universe mode gre remote 224.66.66.66 local <Your_real_addr> ttl 255
|
|
ip addr add 10.66.66.<somewhat>/24 dev Universe
|
|
ifconfig Universe up
|
|
ifconfig Universe add fe80::<Your_real_addr>/10
|
|
ifconfig Universe add fec0:6666:6666::<Your_real_addr>/96
|
|
ftp 10.66.66.66
|
|
...
|
|
ftp fec0:6666:6666::193.233.7.65
|
|
...
|
|
|
|
*/
|
|
|
|
static int ipgre_header(struct sk_buff *skb, struct net_device *dev, unsigned short type,
|
|
void *daddr, void *saddr, unsigned len)
|
|
{
|
|
struct ip_tunnel *t = netdev_priv(dev);
|
|
struct iphdr *iph = (struct iphdr *)skb_push(skb, t->hlen);
|
|
u16 *p = (u16*)(iph+1);
|
|
|
|
memcpy(iph, &t->parms.iph, sizeof(struct iphdr));
|
|
p[0] = t->parms.o_flags;
|
|
p[1] = htons(type);
|
|
|
|
/*
|
|
* Set the source hardware address.
|
|
*/
|
|
|
|
if (saddr)
|
|
memcpy(&iph->saddr, saddr, 4);
|
|
|
|
if (daddr) {
|
|
memcpy(&iph->daddr, daddr, 4);
|
|
return t->hlen;
|
|
}
|
|
if (iph->daddr && !MULTICAST(iph->daddr))
|
|
return t->hlen;
|
|
|
|
return -t->hlen;
|
|
}
|
|
|
|
static int ipgre_open(struct net_device *dev)
|
|
{
|
|
struct ip_tunnel *t = netdev_priv(dev);
|
|
|
|
if (MULTICAST(t->parms.iph.daddr)) {
|
|
struct flowi fl = { .oif = t->parms.link,
|
|
.nl_u = { .ip4_u =
|
|
{ .daddr = t->parms.iph.daddr,
|
|
.saddr = t->parms.iph.saddr,
|
|
.tos = RT_TOS(t->parms.iph.tos) } },
|
|
.proto = IPPROTO_GRE };
|
|
struct rtable *rt;
|
|
if (ip_route_output_key(&rt, &fl))
|
|
return -EADDRNOTAVAIL;
|
|
dev = rt->u.dst.dev;
|
|
ip_rt_put(rt);
|
|
if (__in_dev_get_rtnl(dev) == NULL)
|
|
return -EADDRNOTAVAIL;
|
|
t->mlink = dev->ifindex;
|
|
ip_mc_inc_group(__in_dev_get_rtnl(dev), t->parms.iph.daddr);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int ipgre_close(struct net_device *dev)
|
|
{
|
|
struct ip_tunnel *t = netdev_priv(dev);
|
|
if (MULTICAST(t->parms.iph.daddr) && t->mlink) {
|
|
struct in_device *in_dev = inetdev_by_index(t->mlink);
|
|
if (in_dev) {
|
|
ip_mc_dec_group(in_dev, t->parms.iph.daddr);
|
|
in_dev_put(in_dev);
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
#endif
|
|
|
|
static void ipgre_tunnel_setup(struct net_device *dev)
|
|
{
|
|
SET_MODULE_OWNER(dev);
|
|
dev->uninit = ipgre_tunnel_uninit;
|
|
dev->destructor = free_netdev;
|
|
dev->hard_start_xmit = ipgre_tunnel_xmit;
|
|
dev->get_stats = ipgre_tunnel_get_stats;
|
|
dev->do_ioctl = ipgre_tunnel_ioctl;
|
|
dev->change_mtu = ipgre_tunnel_change_mtu;
|
|
|
|
dev->type = ARPHRD_IPGRE;
|
|
dev->hard_header_len = LL_MAX_HEADER + sizeof(struct iphdr) + 4;
|
|
dev->mtu = ETH_DATA_LEN - sizeof(struct iphdr) - 4;
|
|
dev->flags = IFF_NOARP;
|
|
dev->iflink = 0;
|
|
dev->addr_len = 4;
|
|
}
|
|
|
|
static int ipgre_tunnel_init(struct net_device *dev)
|
|
{
|
|
struct net_device *tdev = NULL;
|
|
struct ip_tunnel *tunnel;
|
|
struct iphdr *iph;
|
|
int hlen = LL_MAX_HEADER;
|
|
int mtu = ETH_DATA_LEN;
|
|
int addend = sizeof(struct iphdr) + 4;
|
|
|
|
tunnel = netdev_priv(dev);
|
|
iph = &tunnel->parms.iph;
|
|
|
|
tunnel->dev = dev;
|
|
strcpy(tunnel->parms.name, dev->name);
|
|
|
|
memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4);
|
|
memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4);
|
|
|
|
/* Guess output device to choose reasonable mtu and hard_header_len */
|
|
|
|
if (iph->daddr) {
|
|
struct flowi fl = { .oif = tunnel->parms.link,
|
|
.nl_u = { .ip4_u =
|
|
{ .daddr = iph->daddr,
|
|
.saddr = iph->saddr,
|
|
.tos = RT_TOS(iph->tos) } },
|
|
.proto = IPPROTO_GRE };
|
|
struct rtable *rt;
|
|
if (!ip_route_output_key(&rt, &fl)) {
|
|
tdev = rt->u.dst.dev;
|
|
ip_rt_put(rt);
|
|
}
|
|
|
|
dev->flags |= IFF_POINTOPOINT;
|
|
|
|
#ifdef CONFIG_NET_IPGRE_BROADCAST
|
|
if (MULTICAST(iph->daddr)) {
|
|
if (!iph->saddr)
|
|
return -EINVAL;
|
|
dev->flags = IFF_BROADCAST;
|
|
dev->hard_header = ipgre_header;
|
|
dev->open = ipgre_open;
|
|
dev->stop = ipgre_close;
|
|
}
|
|
#endif
|
|
}
|
|
|
|
if (!tdev && tunnel->parms.link)
|
|
tdev = __dev_get_by_index(tunnel->parms.link);
|
|
|
|
if (tdev) {
|
|
hlen = tdev->hard_header_len;
|
|
mtu = tdev->mtu;
|
|
}
|
|
dev->iflink = tunnel->parms.link;
|
|
|
|
/* Precalculate GRE options length */
|
|
if (tunnel->parms.o_flags&(GRE_CSUM|GRE_KEY|GRE_SEQ)) {
|
|
if (tunnel->parms.o_flags&GRE_CSUM)
|
|
addend += 4;
|
|
if (tunnel->parms.o_flags&GRE_KEY)
|
|
addend += 4;
|
|
if (tunnel->parms.o_flags&GRE_SEQ)
|
|
addend += 4;
|
|
}
|
|
dev->hard_header_len = hlen + addend;
|
|
dev->mtu = mtu - addend;
|
|
tunnel->hlen = addend;
|
|
return 0;
|
|
}
|
|
|
|
static int __init ipgre_fb_tunnel_init(struct net_device *dev)
|
|
{
|
|
struct ip_tunnel *tunnel = netdev_priv(dev);
|
|
struct iphdr *iph = &tunnel->parms.iph;
|
|
|
|
tunnel->dev = dev;
|
|
strcpy(tunnel->parms.name, dev->name);
|
|
|
|
iph->version = 4;
|
|
iph->protocol = IPPROTO_GRE;
|
|
iph->ihl = 5;
|
|
tunnel->hlen = sizeof(struct iphdr) + 4;
|
|
|
|
dev_hold(dev);
|
|
tunnels_wc[0] = tunnel;
|
|
return 0;
|
|
}
|
|
|
|
|
|
static struct net_protocol ipgre_protocol = {
|
|
.handler = ipgre_rcv,
|
|
.err_handler = ipgre_err,
|
|
};
|
|
|
|
|
|
/*
|
|
* And now the modules code and kernel interface.
|
|
*/
|
|
|
|
static int __init ipgre_init(void)
|
|
{
|
|
int err;
|
|
|
|
printk(KERN_INFO "GRE over IPv4 tunneling driver\n");
|
|
|
|
if (inet_add_protocol(&ipgre_protocol, IPPROTO_GRE) < 0) {
|
|
printk(KERN_INFO "ipgre init: can't add protocol\n");
|
|
return -EAGAIN;
|
|
}
|
|
|
|
ipgre_fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel), "gre0",
|
|
ipgre_tunnel_setup);
|
|
if (!ipgre_fb_tunnel_dev) {
|
|
err = -ENOMEM;
|
|
goto err1;
|
|
}
|
|
|
|
ipgre_fb_tunnel_dev->init = ipgre_fb_tunnel_init;
|
|
|
|
if ((err = register_netdev(ipgre_fb_tunnel_dev)))
|
|
goto err2;
|
|
out:
|
|
return err;
|
|
err2:
|
|
free_netdev(ipgre_fb_tunnel_dev);
|
|
err1:
|
|
inet_del_protocol(&ipgre_protocol, IPPROTO_GRE);
|
|
goto out;
|
|
}
|
|
|
|
static void __exit ipgre_destroy_tunnels(void)
|
|
{
|
|
int prio;
|
|
|
|
for (prio = 0; prio < 4; prio++) {
|
|
int h;
|
|
for (h = 0; h < HASH_SIZE; h++) {
|
|
struct ip_tunnel *t;
|
|
while ((t = tunnels[prio][h]) != NULL)
|
|
unregister_netdevice(t->dev);
|
|
}
|
|
}
|
|
}
|
|
|
|
static void __exit ipgre_fini(void)
|
|
{
|
|
if (inet_del_protocol(&ipgre_protocol, IPPROTO_GRE) < 0)
|
|
printk(KERN_INFO "ipgre close: can't remove protocol\n");
|
|
|
|
rtnl_lock();
|
|
ipgre_destroy_tunnels();
|
|
rtnl_unlock();
|
|
}
|
|
|
|
module_init(ipgre_init);
|
|
module_exit(ipgre_fini);
|
|
MODULE_LICENSE("GPL");
|