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                                 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, (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
  76 static 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
  96         if (xfrm_init_state(t))
  97                 goto error;
  98
  99         atomic_set(&t->tunnel_users, 1);
 100
 101 out:
 102         return t;
 103
 104 error:
 105         t->km.state = XFRM_STATE_DEAD;
 106         xfrm_state_put(t);
 107         t = NULL;
 108         goto out;
 109 }
 110
 111 static int ipcomp6_tunnel_attach(struct xfrm_state *x)
 112 {
 113         struct net *net = xs_net(x);
 114         int err = 0;
 115         struct xfrm_state *t = NULL;
 116         __be32 spi;
 117
 118         spi = xfrm6_tunnel_spi_lookup(net, (xfrm_address_t *)&x->props.saddr);
 119         if (spi)
 120                 t = xfrm_state_lookup(net, (xfrm_address_t *)&x->id.daddr,
 121                                               spi, IPPROTO_IPV6, AF_INET6);
 122         if (!t) {
 123                 t = ipcomp6_tunnel_create(x);
 124                 if (!t) {
 125                         err = -EINVAL;
 126                         goto out;
 127                 }
 128                 xfrm_state_insert(t);
 129                 xfrm_state_hold(t);
 130         }
 131         x->tunnel = t;
 132         atomic_inc(&t->tunnel_users);
 133
 134 out:
 135         return err;
 136 }
 137
 138 static int ipcomp6_init_state(struct xfrm_state *x)
 139 {
 140         int err = -EINVAL;
 141
 142         x->props.header_len = 0;
 143         switch (x->props.mode) {
 144         case XFRM_MODE_TRANSPORT:
 145                 break;
 146         case XFRM_MODE_TUNNEL:
 147                 x->props.header_len += sizeof(struct ipv6hdr);
 148                 break;
 149         default:
 150                 goto out;
 151         }
 152
 153         err = ipcomp_init_state(x);
 154         if (err)
 155                 goto out;
 156
 157         if (x->props.mode == XFRM_MODE_TUNNEL) {
 158                 err = ipcomp6_tunnel_attach(x);
 159                 if (err)
 160                         goto error_tunnel;
 161         }
 162
 163         err = 0;
 164 out:
 165         return err;
 166 error_tunnel:
 167         ipcomp_destroy(x);
 168
 169         goto out;
 170 }
 171
 172 static const struct xfrm_type ipcomp6_type =
 173 {
 174         .description    = "IPCOMP6",
 175         .owner          = THIS_MODULE,
 176         .proto          = IPPROTO_COMP,
 177         .init_state     = ipcomp6_init_state,
 178         .destructor     = ipcomp_destroy,
 179         .input          = ipcomp_input,
 180         .output         = ipcomp_output,
 181         .hdr_offset     = xfrm6_find_1stfragopt,
 182 };
 183
 184 static const struct inet6_protocol ipcomp6_protocol =
 185 {
 186         .handler        = xfrm6_rcv,
 187         .err_handler    = ipcomp6_err,
 188         .flags          = INET6_PROTO_NOPOLICY,
 189 };
 190
 191 static int __init ipcomp6_init(void)
 192 {
 193         if (xfrm_register_type(&ipcomp6_type, AF_INET6) < 0) {
 194                 printk(KERN_INFO "ipcomp6 init: can't add xfrm type\n");
 195                 return -EAGAIN;
 196         }
 197         if (inet6_add_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0) {
 198                 printk(KERN_INFO "ipcomp6 init: can't add protocol\n");
 199                 xfrm_unregister_type(&ipcomp6_type, AF_INET6);
 200                 return -EAGAIN;
 201         }
 202         return 0;
 203 }
 204
 205 static void __exit ipcomp6_fini(void)
 206 {
 207         if (inet6_del_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0)
 208                 printk(KERN_INFO "ipv6 ipcomp close: can't remove protocol\n");
 209         if (xfrm_unregister_type(&ipcomp6_type, AF_INET6) < 0)
 210                 printk(KERN_INFO "ipv6 ipcomp close: can't remove xfrm type\n");
 211 }
 212
 213 module_init(ipcomp6_init);
 214 module_exit(ipcomp6_fini);
 215 MODULE_LICENSE("GPL");
 216 MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173");
 217 MODULE_AUTHOR("Mitsuru KANDA <mk@linux-ipv6.org>");
 218
 219 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_COMP);