net/ipv6/ipcomp6.c

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