linux/net/ipv6/ipcomp6.c
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   1/*
   2 * IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173
   3 *
   4 * Copyright (C)2003 USAGI/WIDE Project
   5 *
   6 * Author       Mitsuru KANDA  <mk@linux-ipv6.org>
   7 *
   8 * This program is free software; you can redistribute it and/or modify
   9 * it under the terms of the GNU General Public License as published by
  10 * the Free Software Foundation; either version 2 of the License, or
  11 * (at your option) any later version.
  12 *
  13 * This program is distributed in the hope that it will be useful,
  14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 * GNU General Public License for more details.
  17 *
  18 * You should have received a copy of the GNU General Public License
  19 * along with this program; if not, write to the Free Software
  20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  21 */
  22/*
  23 * [Memo]
  24 *
  25 * Outbound:
  26 *  The compression of IP datagram MUST be done before AH/ESP processing,
  27 *  fragmentation, and the addition of Hop-by-Hop/Routing header.
  28 *
  29 * Inbound:
  30 *  The decompression of IP datagram MUST be done after the reassembly,
  31 *  AH/ESP processing.
  32 */
  33#include <linux/module.h>
  34#include <net/ip.h>
  35#include <net/xfrm.h>
  36#include <net/ipcomp.h>
  37#include <linux/crypto.h>
  38#include <linux/err.h>
  39#include <linux/pfkeyv2.h>
  40#include <linux/random.h>
  41#include <linux/percpu.h>
  42#include <linux/smp.h>
  43#include <linux/list.h>
  44#include <linux/vmalloc.h>
  45#include <linux/rtnetlink.h>
  46#include <net/icmp.h>
  47#include <net/ipv6.h>
  48#include <net/protocol.h>
  49#include <linux/ipv6.h>
  50#include <linux/icmpv6.h>
  51#include <linux/mutex.h>
  52
  53static void ipcomp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
  54                                u8 type, u8 code, int offset, __be32 info)
  55{
  56        struct net *net = dev_net(skb->dev);
  57        __be32 spi;
  58        struct ipv6hdr *iph = (struct ipv6hdr*)skb->data;
  59        struct ip_comp_hdr *ipcomph =
  60                (struct ip_comp_hdr *)(skb->data + offset);
  61        struct xfrm_state *x;
  62
  63        if (type != ICMPV6_DEST_UNREACH && type != ICMPV6_PKT_TOOBIG)
  64                return;
  65
  66        spi = htonl(ntohs(ipcomph->cpi));
  67        x = xfrm_state_lookup(net, skb->mark, (xfrm_address_t *)&iph->daddr, spi, IPPROTO_COMP, AF_INET6);
  68        if (!x)
  69                return;
  70
  71        printk(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/%pI6\n",
  72                        spi, &iph->daddr);
  73        xfrm_state_put(x);
  74}
  75
  76static struct xfrm_state *ipcomp6_tunnel_create(struct xfrm_state *x)
  77{
  78        struct net *net = xs_net(x);
  79        struct xfrm_state *t = NULL;
  80
  81        t = xfrm_state_alloc(net);
  82        if (!t)
  83                goto out;
  84
  85        t->id.proto = IPPROTO_IPV6;
  86        t->id.spi = xfrm6_tunnel_alloc_spi(net, (xfrm_address_t *)&x->props.saddr);
  87        if (!t->id.spi)
  88                goto error;
  89
  90        memcpy(t->id.daddr.a6, x->id.daddr.a6, sizeof(struct in6_addr));
  91        memcpy(&t->sel, &x->sel, sizeof(t->sel));
  92        t->props.family = AF_INET6;
  93        t->props.mode = x->props.mode;
  94        memcpy(t->props.saddr.a6, x->props.saddr.a6, sizeof(struct in6_addr));
  95        memcpy(&t->mark, &x->mark, sizeof(t->mark));
  96
  97        if (xfrm_init_state(t))
  98                goto error;
  99
 100        atomic_set(&t->tunnel_users, 1);
 101
 102out:
 103        return t;
 104
 105error:
 106        t->km.state = XFRM_STATE_DEAD;
 107        xfrm_state_put(t);
 108        t = NULL;
 109        goto out;
 110}
 111
 112static int ipcomp6_tunnel_attach(struct xfrm_state *x)
 113{
 114        struct net *net = xs_net(x);
 115        int err = 0;
 116        struct xfrm_state *t = NULL;
 117        __be32 spi;
 118        u32 mark = x->mark.m & x->mark.v;
 119
 120        spi = xfrm6_tunnel_spi_lookup(net, (xfrm_address_t *)&x->props.saddr);
 121        if (spi)
 122                t = xfrm_state_lookup(net, mark, (xfrm_address_t *)&x->id.daddr,
 123                                              spi, IPPROTO_IPV6, AF_INET6);
 124        if (!t) {
 125                t = ipcomp6_tunnel_create(x);
 126                if (!t) {
 127                        err = -EINVAL;
 128                        goto out;
 129                }
 130                xfrm_state_insert(t);
 131                xfrm_state_hold(t);
 132        }
 133        x->tunnel = t;
 134        atomic_inc(&t->tunnel_users);
 135
 136out:
 137        return err;
 138}
 139
 140static int ipcomp6_init_state(struct xfrm_state *x)
 141{
 142        int err = -EINVAL;
 143
 144        x->props.header_len = 0;
 145        switch (x->props.mode) {
 146        case XFRM_MODE_TRANSPORT:
 147                break;
 148        case XFRM_MODE_TUNNEL:
 149                x->props.header_len += sizeof(struct ipv6hdr);
 150                break;
 151        default:
 152                goto out;
 153        }
 154
 155        err = ipcomp_init_state(x);
 156        if (err)
 157                goto out;
 158
 159        if (x->props.mode == XFRM_MODE_TUNNEL) {
 160                err = ipcomp6_tunnel_attach(x);
 161                if (err)
 162                        goto out;
 163        }
 164
 165        err = 0;
 166out:
 167        return err;
 168}
 169
 170static const struct xfrm_type ipcomp6_type =
 171{
 172        .description    = "IPCOMP6",
 173        .owner          = THIS_MODULE,
 174        .proto          = IPPROTO_COMP,
 175        .init_state     = ipcomp6_init_state,
 176        .destructor     = ipcomp_destroy,
 177        .input          = ipcomp_input,
 178        .output         = ipcomp_output,
 179        .hdr_offset     = xfrm6_find_1stfragopt,
 180};
 181
 182static const struct inet6_protocol ipcomp6_protocol =
 183{
 184        .handler        = xfrm6_rcv,
 185        .err_handler    = ipcomp6_err,
 186        .flags          = INET6_PROTO_NOPOLICY,
 187};
 188
 189static int __init ipcomp6_init(void)
 190{
 191        if (xfrm_register_type(&ipcomp6_type, AF_INET6) < 0) {
 192                printk(KERN_INFO "ipcomp6 init: can't add xfrm type\n");
 193                return -EAGAIN;
 194        }
 195        if (inet6_add_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0) {
 196                printk(KERN_INFO "ipcomp6 init: can't add protocol\n");
 197                xfrm_unregister_type(&ipcomp6_type, AF_INET6);
 198                return -EAGAIN;
 199        }
 200        return 0;
 201}
 202
 203static void __exit ipcomp6_fini(void)
 204{
 205        if (inet6_del_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0)
 206                printk(KERN_INFO "ipv6 ipcomp close: can't remove protocol\n");
 207        if (xfrm_unregister_type(&ipcomp6_type, AF_INET6) < 0)
 208                printk(KERN_INFO "ipv6 ipcomp close: can't remove xfrm type\n");
 209}
 210
 211module_init(ipcomp6_init);
 212module_exit(ipcomp6_fini);
 213MODULE_LICENSE("GPL");
 214MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173");
 215MODULE_AUTHOR("Mitsuru KANDA <mk@linux-ipv6.org>");
 216
 217MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_COMP);
 218