1 /* 2 * IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173 3 * 4 * Copyright (C)2003 USAGI/WIDE Project 5 * 6 * Author Mitsuru KANDA <[email protected]> 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_DEST_UNREACH && type != ICMPV6_PKT_TOOBIG) 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 pr_debug("pmtu discovery on SA IPCOMP/%08x/%pI6\n", 77 spi, &iph->daddr); 78 ip6_update_pmtu(skb, net, info, 0, 0); 79 xfrm_state_put(x); 80 } 81 82 static struct xfrm_state *ipcomp6_tunnel_create(struct xfrm_state *x) 83 { 84 struct net *net = xs_net(x); 85 struct xfrm_state *t = NULL; 86 87 t = xfrm_state_alloc(net); 88 if (!t) 89 goto out; 90 91 t->id.proto = IPPROTO_IPV6; 92 t->id.spi = xfrm6_tunnel_alloc_spi(net, (xfrm_address_t *)&x->props.saddr); 93 if (!t->id.spi) 94 goto error; 95 96 memcpy(t->id.daddr.a6, x->id.daddr.a6, sizeof(struct in6_addr)); 97 memcpy(&t->sel, &x->sel, sizeof(t->sel)); 98 t->props.family = AF_INET6; 99 t->props.mode = x->props.mode; 100 memcpy(t->props.saddr.a6, x->props.saddr.a6, sizeof(struct in6_addr)); 101 memcpy(&t->mark, &x->mark, sizeof(t->mark)); 102 103 if (xfrm_init_state(t)) 104 goto error; 105 106 atomic_set(&t->tunnel_users, 1); 107 108 out: 109 return t; 110 111 error: 112 t->km.state = XFRM_STATE_DEAD; 113 xfrm_state_put(t); 114 t = NULL; 115 goto out; 116 } 117 118 static int ipcomp6_tunnel_attach(struct xfrm_state *x) 119 { 120 struct net *net = xs_net(x); 121 int err = 0; 122 struct xfrm_state *t = NULL; 123 __be32 spi; 124 u32 mark = x->mark.m & x->mark.v; 125 126 spi = xfrm6_tunnel_spi_lookup(net, (xfrm_address_t *)&x->props.saddr); 127 if (spi) 128 t = xfrm_state_lookup(net, mark, (xfrm_address_t *)&x->id.daddr, 129 spi, IPPROTO_IPV6, AF_INET6); 130 if (!t) { 131 t = ipcomp6_tunnel_create(x); 132 if (!t) { 133 err = -EINVAL; 134 goto out; 135 } 136 xfrm_state_insert(t); 137 xfrm_state_hold(t); 138 } 139 x->tunnel = t; 140 atomic_inc(&t->tunnel_users); 141 142 out: 143 return err; 144 } 145 146 static int ipcomp6_init_state(struct xfrm_state *x) 147 { 148 int err = -EINVAL; 149 150 x->props.header_len = 0; 151 switch (x->props.mode) { 152 case XFRM_MODE_TRANSPORT: 153 break; 154 case XFRM_MODE_TUNNEL: 155 x->props.header_len += sizeof(struct ipv6hdr); 156 break; 157 default: 158 goto out; 159 } 160 161 err = ipcomp_init_state(x); 162 if (err) 163 goto out; 164 165 if (x->props.mode == XFRM_MODE_TUNNEL) { 166 err = ipcomp6_tunnel_attach(x); 167 if (err) 168 goto out; 169 } 170 171 err = 0; 172 out: 173 return err; 174 } 175 176 static const struct xfrm_type ipcomp6_type = 177 { 178 .description = "IPCOMP6", 179 .owner = THIS_MODULE, 180 .proto = IPPROTO_COMP, 181 .init_state = ipcomp6_init_state, 182 .destructor = ipcomp_destroy, 183 .input = ipcomp_input, 184 .output = ipcomp_output, 185 .hdr_offset = xfrm6_find_1stfragopt, 186 }; 187 188 static const struct inet6_protocol ipcomp6_protocol = 189 { 190 .handler = xfrm6_rcv, 191 .err_handler = ipcomp6_err, 192 .flags = INET6_PROTO_NOPOLICY, 193 }; 194 195 static int __init ipcomp6_init(void) 196 { 197 if (xfrm_register_type(&ipcomp6_type, AF_INET6) < 0) { 198 pr_info("%s: can't add xfrm type\n", __func__); 199 return -EAGAIN; 200 } 201 if (inet6_add_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0) { 202 pr_info("%s: can't add protocol\n", __func__); 203 xfrm_unregister_type(&ipcomp6_type, AF_INET6); 204 return -EAGAIN; 205 } 206 return 0; 207 } 208 209 static void __exit ipcomp6_fini(void) 210 { 211 if (inet6_del_protocol(&ipcomp6_protocol, IPPROTO_COMP) < 0) 212 pr_info("%s: can't remove protocol\n", __func__); 213 if (xfrm_unregister_type(&ipcomp6_type, AF_INET6) < 0) 214 pr_info("%s: can't remove xfrm type\n", __func__); 215 } 216 217 module_init(ipcomp6_init); 218 module_exit(ipcomp6_fini); 219 MODULE_LICENSE("GPL"); 220 MODULE_DESCRIPTION("IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173"); 221 MODULE_AUTHOR("Mitsuru KANDA <[email protected]>"); 222 223 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_COMP); 224