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 #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
  53 static void ipcomp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
  54                                 int type, int code, int offset, __be32 info)
  55 {
  56         __be32 spi;
  57         struct ipv6hdr *iph = (struct ipv6hdr*)skb->data;
  58         struct ip_comp_hdr *ipcomph =
  59                 (struct ip_comp_hdr *)(skb->data + offset);
  60         struct xfrm_state *x;
  61
  62         if (type != ICMPV6_DEST_UNREACH && type != ICMPV6_PKT_TOOBIG)
  63                 return;
  64
  65         spi = htonl(ntohs(ipcomph->cpi));
  66         x = xfrm_state_lookup(&init_net, (xfrm_address_t *)&iph->daddr, spi, IPPROTO_COMP, AF_INET6);
  67         if (!x)
  68                 return;
  69
  70         printk(KERN_DEBUG "pmtu discovery on SA IPCOMP/%08x/%pI6\n",
  71                         spi, &iph->daddr);
  72         xfrm_state_put(x);
  73 }
  74
  75 static struct xfrm_state *ipcomp6_tunnel_create(struct xfrm_state *x)
  76 {
  77         struct xfrm_state *t = NULL;
  78
  79         t = xfrm_state_alloc(&init_net);
  80         if (!t)
  81                 goto out;
  82
  83         t->id.proto = IPPROTO_IPV6;
  84         t->id.spi = xfrm6_tunnel_alloc_spi((xfrm_address_t *)&x->props.saddr);
  85         if (!t->id.spi)
  86                 goto error;
  87
  88         memcpy(t->id.daddr.a6, x->id.daddr.a6, sizeof(struct in6_addr));
  89         memcpy(&t->sel, &x->sel, sizeof(t->sel));
  90         t->props.family = AF_INET6;
  91         t->props.mode = x->props.mode;
  92         memcpy(t->props.saddr.a6, x->props.saddr.a6, sizeof(struct in6_addr));
  93
  94         if (xfrm_init_state(t))
  95                 goto error;
  96
  97         atomic_set(&t->tunnel_users, 1);
  98
  99 out:
 100         return t;
 101
 102 error:
 103         t->km.state = XFRM_STATE_DEAD;
 104         xfrm_state_put(t);
 105         t = NULL;
 106         goto out;
 107 }
 108
 109 static int ipcomp6_tunnel_attach(struct xfrm_state *x)
 110 {
 111         int err = 0;
 112         struct xfrm_state *t = NULL;
 113         __be32 spi;
 114
 115         spi = xfrm6_tunnel_spi_lookup((xfrm_address_t *)&x->props.saddr);
 116         if (spi)
 117                 t = xfrm_state_lookup(&init_net, (xfrm_address_t *)&x->id.daddr,
 118                                               spi, IPPROTO_IPV6, AF_INET6);
 119         if (!t) {
 120                 t = ipcomp6_tunnel_create(x);
 121                 if (!t) {
 122                         err = -EINVAL;
 123                         goto out;
 124                 }
 125                 xfrm_state_insert(t);
 126                 xfrm_state_hold(t);
 127         }
 128         x->tunnel = t;
 129         atomic_inc(&t->tunnel_users);
 130
 131 out:
 132         return err;
 133 }
 134
 135 static int ipcomp6_init_state(struct xfrm_state *x)
 136 {
 137         int err = -EINVAL;
 138
 139         x->props.header_len = 0;
 140         switch (x->props.mode) {
 141         case XFRM_MODE_TRANSPORT:
 142                 break;
 143         case XFRM_MODE_TUNNEL:
 144                 x->props.header_len += sizeof(struct ipv6hdr);
 145                 break;
 146         default:
 147                 goto out;
 148         }
 149
 150         err = ipcomp_init_state(x);
 151         if (err)
 152                 goto out;
 153
 154         if (x->props.mode == XFRM_MODE_TUNNEL) {
 155                 err = ipcomp6_tunnel_attach(x);
 156                 if (err)
 157                         goto error_tunnel;
 158         }
 159
 160         err = 0;
 161 out:
 162         return err;
 163 error_tunnel:
 164         ipcomp_destroy(x);
 165
 166         goto out;
 167 }
 168
 169 static const struct xfrm_type ipcomp6_type =
 170 {
 171         .description    = "IPCOMP6",
 172         .owner          = THIS_MODULE,
 173         .proto          = IPPROTO_COMP,
 174         .init_state     = ipcomp6_init_state,
 175         .destructor     = ipcomp_destroy,
 176         .input          = ipcomp_input,
 177         .output         = ipcomp_output,
 178         .hdr_offset     = xfrm6_find_1stfragopt,
 179 };
 180
 181 static struct inet6_protocol ipcomp6_protocol =
 182 {
 183         .handler        = xfrm6_rcv,
 184         .err_handler    = ipcomp6_err,
 185         .flags          = INET6_PROTO_NOPOLICY,
 186 };
 187
 188 static int __init ipcomp6_init(void)
 189 {
 190         if (xfrm_register_type(&ipcomp6_type, AF_INET6) < 0) {
 191                 printk(KERN_INFO "ipcomp6 init: can't add xfrm type\n");
 192                 return -EAGAIN;
 193         }
 194         if (inet6_add_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0) {
 195                 printk(KERN_INFO "ipcomp6 init: can't add protocol\n");
 196                 xfrm_unregister_type(&ipcomp6_type, AF_INET6);
 197                 return -EAGAIN;
 198         }
 199         return 0;
 200 }
 201
 202 static void __exit ipcomp6_fini(void)
 203 {
 204         if (inet6_del_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0)
 205                 printk(KERN_INFO "ipv6 ipcomp close: can't remove protocol\n");
 206         if (xfrm_unregister_type(&ipcomp6_type, AF_INET6) < 0)
 207                 printk(KERN_INFO "ipv6 ipcomp close: can't remove xfrm type\n");
 208 }
 209
 210 module_init(ipcomp6_init);
 211 module_exit(ipcomp6_fini);
 212 MODULE_LICENSE("GPL");
 213 MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173");
 214 MODULE_AUTHOR("Mitsuru KANDA <mk@linux-ipv6.org>");
 215
 216 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_COMP);