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
  34#define pr_fmt(fmt) "IPv6: " fmt
  35
  36#include <linux/module.h>
  37#include <net/ip.h>
  38#include <net/xfrm.h>
  39#include <net/ipcomp.h>
  40#include <linux/crypto.h>
  41#include <linux/err.h>
  42#include <linux/pfkeyv2.h>
  43#include <linux/random.h>
  44#include <linux/percpu.h>
  45#include <linux/smp.h>
  46#include <linux/list.h>
  47#include <linux/vmalloc.h>
  48#include <linux/rtnetlink.h>
  49#include <net/ip6_route.h>
  50#include <net/icmp.h>
  51#include <net/ipv6.h>
  52#include <net/protocol.h>
  53#include <linux/ipv6.h>
  54#include <linux/icmpv6.h>
  55#include <linux/mutex.h>
  56
  57static void ipcomp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
  58                                u8 type, u8 code, int offset, __be32 info)
  59{
  60        struct net *net = dev_net(skb->dev);
  61        __be32 spi;
  62        const struct ipv6hdr *iph = (const struct ipv6hdr *)skb->data;
  63        struct ip_comp_hdr *ipcomph =
  64                (struct ip_comp_hdr *)(skb->data + offset);
  65        struct xfrm_state *x;
  66
  67        if (type != ICMPV6_DEST_UNREACH &&
  68            type != ICMPV6_PKT_TOOBIG &&
  69            type != NDISC_REDIRECT)
  70                return;
  71
  72        spi = htonl(ntohs(ipcomph->cpi));
  73        x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
  74                              spi, IPPROTO_COMP, AF_INET6);
  75        if (!x)
  76                return;
  77
  78        if (type == NDISC_REDIRECT)
  79                ip6_redirect(skb, net, 0, 0);
  80        else
  81                ip6_update_pmtu(skb, net, info, 0, 0);
  82        xfrm_state_put(x);
  83}
  84
  85static struct xfrm_state *ipcomp6_tunnel_create(struct xfrm_state *x)
  86{
  87        struct net *net = xs_net(x);
  88        struct xfrm_state *t = NULL;
  89
  90        t = xfrm_state_alloc(net);
  91        if (!t)
  92                goto out;
  93
  94        t->id.proto = IPPROTO_IPV6;
  95        t->id.spi = xfrm6_tunnel_alloc_spi(net, (xfrm_address_t *)&x->props.saddr);
  96        if (!t->id.spi)
  97                goto error;
  98
  99        memcpy(t->id.daddr.a6, x->id.daddr.a6, sizeof(struct in6_addr));
 100        memcpy(&t->sel, &x->sel, sizeof(t->sel));
 101        t->props.family = AF_INET6;
 102        t->props.mode = x->props.mode;
 103        memcpy(t->props.saddr.a6, x->props.saddr.a6, sizeof(struct in6_addr));
 104        memcpy(&t->mark, &x->mark, sizeof(t->mark));
 105
 106        if (xfrm_init_state(t))
 107                goto error;
 108
 109        atomic_set(&t->tunnel_users, 1);
 110
 111out:
 112        return t;
 113
 114error:
 115        t->km.state = XFRM_STATE_DEAD;
 116        xfrm_state_put(t);
 117        t = NULL;
 118        goto out;
 119}
 120
 121static int ipcomp6_tunnel_attach(struct xfrm_state *x)
 122{
 123        struct net *net = xs_net(x);
 124        int err = 0;
 125        struct xfrm_state *t = NULL;
 126        __be32 spi;
 127        u32 mark = x->mark.m & x->mark.v;
 128
 129        spi = xfrm6_tunnel_spi_lookup(net, (xfrm_address_t *)&x->props.saddr);
 130        if (spi)
 131                t = xfrm_state_lookup(net, mark, (xfrm_address_t *)&x->id.daddr,
 132                                              spi, IPPROTO_IPV6, AF_INET6);
 133        if (!t) {
 134                t = ipcomp6_tunnel_create(x);
 135                if (!t) {
 136                        err = -EINVAL;
 137                        goto out;
 138                }
 139                xfrm_state_insert(t);
 140                xfrm_state_hold(t);
 141        }
 142        x->tunnel = t;
 143        atomic_inc(&t->tunnel_users);
 144
 145out:
 146        return err;
 147}
 148
 149static int ipcomp6_init_state(struct xfrm_state *x)
 150{
 151        int err = -EINVAL;
 152
 153        x->props.header_len = 0;
 154        switch (x->props.mode) {
 155        case XFRM_MODE_TRANSPORT:
 156                break;
 157        case XFRM_MODE_TUNNEL:
 158                x->props.header_len += sizeof(struct ipv6hdr);
 159                break;
 160        default:
 161                goto out;
 162        }
 163
 164        err = ipcomp_init_state(x);
 165        if (err)
 166                goto out;
 167
 168        if (x->props.mode == XFRM_MODE_TUNNEL) {
 169                err = ipcomp6_tunnel_attach(x);
 170                if (err)
 171                        goto out;
 172        }
 173
 174        err = 0;
 175out:
 176        return err;
 177}
 178
 179static const struct xfrm_type ipcomp6_type =
 180{
 181        .description    = "IPCOMP6",
 182        .owner          = THIS_MODULE,
 183        .proto          = IPPROTO_COMP,
 184        .init_state     = ipcomp6_init_state,
 185        .destructor     = ipcomp_destroy,
 186        .input          = ipcomp_input,
 187        .output         = ipcomp_output,
 188        .hdr_offset     = xfrm6_find_1stfragopt,
 189};
 190
 191static const struct inet6_protocol ipcomp6_protocol =
 192{
 193        .handler        = xfrm6_rcv,
 194        .err_handler    = ipcomp6_err,
 195        .flags          = INET6_PROTO_NOPOLICY,
 196};
 197
 198static int __init ipcomp6_init(void)
 199{
 200        if (xfrm_register_type(&ipcomp6_type, AF_INET6) < 0) {
 201                pr_info("%s: can't add xfrm type\n", __func__);
 202                return -EAGAIN;
 203        }
 204        if (inet6_add_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0) {
 205                pr_info("%s: can't add protocol\n", __func__);
 206                xfrm_unregister_type(&ipcomp6_type, AF_INET6);
 207                return -EAGAIN;
 208        }
 209        return 0;
 210}
 211
 212static void __exit ipcomp6_fini(void)
 213{
 214        if (inet6_del_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0)
 215                pr_info("%s: can't remove protocol\n", __func__);
 216        if (xfrm_unregister_type(&ipcomp6_type, AF_INET6) < 0)
 217                pr_info("%s: can't remove xfrm type\n", __func__);
 218}
 219
 220module_init(ipcomp6_init);
 221module_exit(ipcomp6_fini);
 222MODULE_LICENSE("GPL");
 223MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173");
 224MODULE_AUTHOR("Mitsuru KANDA <mk@linux-ipv6.org>");
 225
 226MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_COMP);
 227
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