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 int 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 0; 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 0; 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 return 0; 83 } 84 85 static struct xfrm_state *ipcomp6_tunnel_create(struct xfrm_state *x) 86 { 87 struct net *net = xs_net(x); 88 struct xfrm_state *t = NULL; 89 90 t = xfrm_state_alloc(net); 91 if (!t) 92 goto out; 93 94 t->id.proto = IPPROTO_IPV6; 95 t->id.spi = xfrm6_tunnel_alloc_spi(net, (xfrm_address_t *)&x->props.saddr); 96 if (!t->id.spi) 97 goto error; 98 99 memcpy(t->id.daddr.a6, x->id.daddr.a6, sizeof(struct in6_addr)); 100 memcpy(&t->sel, &x->sel, sizeof(t->sel)); 101 t->props.family = AF_INET6; 102 t->props.mode = x->props.mode; 103 memcpy(t->props.saddr.a6, x->props.saddr.a6, sizeof(struct in6_addr)); 104 memcpy(&t->mark, &x->mark, sizeof(t->mark)); 105 106 if (xfrm_init_state(t)) 107 goto error; 108 109 atomic_set(&t->tunnel_users, 1); 110 111 out: 112 return t; 113 114 error: 115 t->km.state = XFRM_STATE_DEAD; 116 xfrm_state_put(t); 117 t = NULL; 118 goto out; 119 } 120 121 static int ipcomp6_tunnel_attach(struct xfrm_state *x) 122 { 123 struct net *net = xs_net(x); 124 int err = 0; 125 struct xfrm_state *t = NULL; 126 __be32 spi; 127 u32 mark = x->mark.m & x->mark.v; 128 129 spi = xfrm6_tunnel_spi_lookup(net, (xfrm_address_t *)&x->props.saddr); 130 if (spi) 131 t = xfrm_state_lookup(net, mark, (xfrm_address_t *)&x->id.daddr, 132 spi, IPPROTO_IPV6, AF_INET6); 133 if (!t) { 134 t = ipcomp6_tunnel_create(x); 135 if (!t) { 136 err = -EINVAL; 137 goto out; 138 } 139 xfrm_state_insert(t); 140 xfrm_state_hold(t); 141 } 142 x->tunnel = t; 143 atomic_inc(&t->tunnel_users); 144 145 out: 146 return err; 147 } 148 149 static int ipcomp6_init_state(struct xfrm_state *x) 150 { 151 int err = -EINVAL; 152 153 x->props.header_len = 0; 154 switch (x->props.mode) { 155 case XFRM_MODE_TRANSPORT: 156 break; 157 case XFRM_MODE_TUNNEL: 158 x->props.header_len += sizeof(struct ipv6hdr); 159 break; 160 default: 161 goto out; 162 } 163 164 err = ipcomp_init_state(x); 165 if (err) 166 goto out; 167 168 if (x->props.mode == XFRM_MODE_TUNNEL) { 169 err = ipcomp6_tunnel_attach(x); 170 if (err) 171 goto out; 172 } 173 174 err = 0; 175 out: 176 return err; 177 } 178 179 static int ipcomp6_rcv_cb(struct sk_buff *skb, int err) 180 { 181 return 0; 182 } 183 184 static const struct xfrm_type ipcomp6_type = { 185 .description = "IPCOMP6", 186 .owner = THIS_MODULE, 187 .proto = IPPROTO_COMP, 188 .init_state = ipcomp6_init_state, 189 .destructor = ipcomp_destroy, 190 .input = ipcomp_input, 191 .output = ipcomp_output, 192 .hdr_offset = xfrm6_find_1stfragopt, 193 }; 194 195 static struct xfrm6_protocol ipcomp6_protocol = { 196 .handler = xfrm6_rcv, 197 .cb_handler = ipcomp6_rcv_cb, 198 .err_handler = ipcomp6_err, 199 .priority = 0, 200 }; 201 202 static int __init ipcomp6_init(void) 203 { 204 if (xfrm_register_type(&ipcomp6_type, AF_INET6) < 0) { 205 pr_info("%s: can't add xfrm type\n", __func__); 206 return -EAGAIN; 207 } 208 if (xfrm6_protocol_register(&ipcomp6_protocol, IPPROTO_COMP) < 0) { 209 pr_info("%s: can't add protocol\n", __func__); 210 xfrm_unregister_type(&ipcomp6_type, AF_INET6); 211 return -EAGAIN; 212 } 213 return 0; 214 } 215 216 static void __exit ipcomp6_fini(void) 217 { 218 if (xfrm6_protocol_deregister(&ipcomp6_protocol, IPPROTO_COMP) < 0) 219 pr_info("%s: can't remove protocol\n", __func__); 220 if (xfrm_unregister_type(&ipcomp6_type, AF_INET6) < 0) 221 pr_info("%s: can't remove xfrm type\n", __func__); 222 } 223 224 module_init(ipcomp6_init); 225 module_exit(ipcomp6_fini); 226 MODULE_LICENSE("GPL"); 227 MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173"); 228 MODULE_AUTHOR("Mitsuru KANDA <mk@linux-ipv6.org>"); 229 230 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_COMP); 231