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, see <http://www.gnu.org/licenses/>. 20 */ 21 /* 22 * [Memo] 23 * 24 * Outbound: 25 * The compression of IP datagram MUST be done before AH/ESP processing, 26 * fragmentation, and the addition of Hop-by-Hop/Routing header. 27 * 28 * Inbound: 29 * The decompression of IP datagram MUST be done after the reassembly, 30 * AH/ESP processing. 31 */ 32 33 #define pr_fmt(fmt) "IPv6: " fmt 34 35 #include <linux/module.h> 36 #include <net/ip.h> 37 #include <net/xfrm.h> 38 #include <net/ipcomp.h> 39 #include <linux/crypto.h> 40 #include <linux/err.h> 41 #include <linux/pfkeyv2.h> 42 #include <linux/random.h> 43 #include <linux/percpu.h> 44 #include <linux/smp.h> 45 #include <linux/list.h> 46 #include <linux/vmalloc.h> 47 #include <linux/rtnetlink.h> 48 #include <net/ip6_route.h> 49 #include <net/icmp.h> 50 #include <net/ipv6.h> 51 #include <net/protocol.h> 52 #include <linux/ipv6.h> 53 #include <linux/icmpv6.h> 54 #include <linux/mutex.h> 55 56 static void ipcomp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, 57 u8 type, u8 code, int offset, __be32 info) 58 { 59 struct net *net = dev_net(skb->dev); 60 __be32 spi; 61 const struct ipv6hdr *iph = (const struct ipv6hdr *)skb->data; 62 struct ip_comp_hdr *ipcomph = 63 (struct ip_comp_hdr *)(skb->data + offset); 64 struct xfrm_state *x; 65 66 if (type != ICMPV6_PKT_TOOBIG && 67 type != NDISC_REDIRECT) 68 return; 69 70 spi = htonl(ntohs(ipcomph->cpi)); 71 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr, 72 spi, IPPROTO_COMP, AF_INET6); 73 if (!x) 74 return; 75 76 if (type == NDISC_REDIRECT) 77 ip6_redirect(skb, net, skb->dev->ifindex, 0); 78 else 79 ip6_update_pmtu(skb, net, info, 0, 0); 80 xfrm_state_put(x); 81 } 82 83 static struct xfrm_state *ipcomp6_tunnel_create(struct xfrm_state *x) 84 { 85 struct net *net = xs_net(x); 86 struct xfrm_state *t = NULL; 87 88 t = xfrm_state_alloc(net); 89 if (!t) 90 goto out; 91 92 t->id.proto = IPPROTO_IPV6; 93 t->id.spi = xfrm6_tunnel_alloc_spi(net, (xfrm_address_t *)&x->props.saddr); 94 if (!t->id.spi) 95 goto error; 96 97 memcpy(t->id.daddr.a6, x->id.daddr.a6, sizeof(struct in6_addr)); 98 memcpy(&t->sel, &x->sel, sizeof(t->sel)); 99 t->props.family = AF_INET6; 100 t->props.mode = x->props.mode; 101 memcpy(t->props.saddr.a6, x->props.saddr.a6, sizeof(struct in6_addr)); 102 memcpy(&t->mark, &x->mark, sizeof(t->mark)); 103 104 if (xfrm_init_state(t)) 105 goto error; 106 107 atomic_set(&t->tunnel_users, 1); 108 109 out: 110 return t; 111 112 error: 113 t->km.state = XFRM_STATE_DEAD; 114 xfrm_state_put(t); 115 t = NULL; 116 goto out; 117 } 118 119 static int ipcomp6_tunnel_attach(struct xfrm_state *x) 120 { 121 struct net *net = xs_net(x); 122 int err = 0; 123 struct xfrm_state *t = NULL; 124 __be32 spi; 125 u32 mark = x->mark.m & x->mark.v; 126 127 spi = xfrm6_tunnel_spi_lookup(net, (xfrm_address_t *)&x->props.saddr); 128 if (spi) 129 t = xfrm_state_lookup(net, mark, (xfrm_address_t *)&x->id.daddr, 130 spi, IPPROTO_IPV6, AF_INET6); 131 if (!t) { 132 t = ipcomp6_tunnel_create(x); 133 if (!t) { 134 err = -EINVAL; 135 goto out; 136 } 137 xfrm_state_insert(t); 138 xfrm_state_hold(t); 139 } 140 x->tunnel = t; 141 atomic_inc(&t->tunnel_users); 142 143 out: 144 return err; 145 } 146 147 static int ipcomp6_init_state(struct xfrm_state *x) 148 { 149 int err = -EINVAL; 150 151 x->props.header_len = 0; 152 switch (x->props.mode) { 153 case XFRM_MODE_TRANSPORT: 154 break; 155 case XFRM_MODE_TUNNEL: 156 x->props.header_len += sizeof(struct ipv6hdr); 157 break; 158 default: 159 goto out; 160 } 161 162 err = ipcomp_init_state(x); 163 if (err) 164 goto out; 165 166 if (x->props.mode == XFRM_MODE_TUNNEL) { 167 err = ipcomp6_tunnel_attach(x); 168 if (err) 169 goto out; 170 } 171 172 err = 0; 173 out: 174 return err; 175 } 176 177 static const struct xfrm_type ipcomp6_type = 178 { 179 .description = "IPCOMP6", 180 .owner = THIS_MODULE, 181 .proto = IPPROTO_COMP, 182 .init_state = ipcomp6_init_state, 183 .destructor = ipcomp_destroy, 184 .input = ipcomp_input, 185 .output = ipcomp_output, 186 .hdr_offset = xfrm6_find_1stfragopt, 187 }; 188 189 static const struct inet6_protocol ipcomp6_protocol = 190 { 191 .handler = xfrm6_rcv, 192 .err_handler = ipcomp6_err, 193 .flags = INET6_PROTO_NOPOLICY, 194 }; 195 196 static int __init ipcomp6_init(void) 197 { 198 if (xfrm_register_type(&ipcomp6_type, AF_INET6) < 0) { 199 pr_info("%s: can't add xfrm type\n", __func__); 200 return -EAGAIN; 201 } 202 if (inet6_add_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0) { 203 pr_info("%s: can't add protocol\n", __func__); 204 xfrm_unregister_type(&ipcomp6_type, AF_INET6); 205 return -EAGAIN; 206 } 207 return 0; 208 } 209 210 static void __exit ipcomp6_fini(void) 211 { 212 if (inet6_del_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0) 213 pr_info("%s: can't remove protocol\n", __func__); 214 if (xfrm_unregister_type(&ipcomp6_type, AF_INET6) < 0) 215 pr_info("%s: can't remove xfrm type\n", __func__); 216 } 217 218 module_init(ipcomp6_init); 219 module_exit(ipcomp6_fini); 220 MODULE_LICENSE("GPL"); 221 MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173"); 222 MODULE_AUTHOR("Mitsuru KANDA <mk@linux-ipv6.org>"); 223 224 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_COMP); 225