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); 226