1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * IP Payload Compression Protocol (IPComp) for IPv6 - RFC3173 4 * 5 * Copyright (C)2003 USAGI/WIDE Project 6 * 7 * Author Mitsuru KANDA <mk@linux-ipv6.org> 8 */ 9 /* 10 * [Memo] 11 * 12 * Outbound: 13 * The compression of IP datagram MUST be done before AH/ESP processing, 14 * fragmentation, and the addition of Hop-by-Hop/Routing header. 15 * 16 * Inbound: 17 * The decompression of IP datagram MUST be done after the reassembly, 18 * AH/ESP processing. 19 */ 20 21 #define pr_fmt(fmt) "IPv6: " fmt 22 23 #include <linux/module.h> 24 #include <net/ip.h> 25 #include <net/xfrm.h> 26 #include <net/ipcomp.h> 27 #include <linux/crypto.h> 28 #include <linux/err.h> 29 #include <linux/pfkeyv2.h> 30 #include <linux/random.h> 31 #include <linux/percpu.h> 32 #include <linux/smp.h> 33 #include <linux/list.h> 34 #include <linux/vmalloc.h> 35 #include <linux/rtnetlink.h> 36 #include <net/ip6_route.h> 37 #include <net/icmp.h> 38 #include <net/ipv6.h> 39 #include <net/protocol.h> 40 #include <linux/ipv6.h> 41 #include <linux/icmpv6.h> 42 #include <linux/mutex.h> 43 44 static int ipcomp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, 45 u8 type, u8 code, int offset, __be32 info) 46 { 47 struct net *net = dev_net(skb->dev); 48 __be32 spi; 49 const struct ipv6hdr *iph = (const struct ipv6hdr *)skb->data; 50 struct ip_comp_hdr *ipcomph = 51 (struct ip_comp_hdr *)(skb->data + offset); 52 struct xfrm_state *x; 53 54 if (type != ICMPV6_PKT_TOOBIG && 55 type != NDISC_REDIRECT) 56 return 0; 57 58 spi = htonl(ntohs(ipcomph->cpi)); 59 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr, 60 spi, IPPROTO_COMP, AF_INET6); 61 if (!x) 62 return 0; 63 64 if (type == NDISC_REDIRECT) 65 ip6_redirect(skb, net, skb->dev->ifindex, 0, 66 sock_net_uid(net, NULL)); 67 else 68 ip6_update_pmtu(skb, net, info, 0, 0, sock_net_uid(net, NULL)); 69 xfrm_state_put(x); 70 71 return 0; 72 } 73 74 static struct lock_class_key xfrm_state_lock_key; 75 static struct xfrm_state *ipcomp6_tunnel_create(struct xfrm_state *x) 76 { 77 struct net *net = xs_net(x); 78 struct xfrm_state *t = NULL; 79 80 t = xfrm_state_alloc(net); 81 if (!t) 82 goto out; 83 lockdep_set_class(&t->lock, &xfrm_state_lock_key); 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 memcpy(&t->mark, &x->mark, sizeof(t->mark)); 96 t->if_id = x->if_id; 97 98 if (xfrm_init_state(t)) 99 goto error; 100 101 atomic_set(&t->tunnel_users, 1); 102 103 out: 104 return t; 105 106 error: 107 t->km.state = XFRM_STATE_DEAD; 108 xfrm_state_put(t); 109 t = NULL; 110 goto out; 111 } 112 113 static int ipcomp6_tunnel_attach(struct xfrm_state *x) 114 { 115 struct net *net = xs_net(x); 116 int err = 0; 117 struct xfrm_state *t = NULL; 118 __be32 spi; 119 u32 mark = x->mark.m & x->mark.v; 120 121 spi = xfrm6_tunnel_spi_lookup(net, (xfrm_address_t *)&x->props.saddr); 122 if (spi) 123 t = xfrm_state_lookup(net, mark, (xfrm_address_t *)&x->id.daddr, 124 spi, IPPROTO_IPV6, AF_INET6); 125 if (!t) { 126 t = ipcomp6_tunnel_create(x); 127 if (!t) { 128 err = -EINVAL; 129 goto out; 130 } 131 xfrm_state_insert(t); 132 xfrm_state_hold(t); 133 } 134 x->tunnel = t; 135 atomic_inc(&t->tunnel_users); 136 137 out: 138 return err; 139 } 140 141 static int ipcomp6_init_state(struct xfrm_state *x, 142 struct netlink_ext_ack *extack) 143 { 144 int err = -EINVAL; 145 146 x->props.header_len = 0; 147 switch (x->props.mode) { 148 case XFRM_MODE_TRANSPORT: 149 break; 150 case XFRM_MODE_TUNNEL: 151 x->props.header_len += sizeof(struct ipv6hdr); 152 break; 153 default: 154 NL_SET_ERR_MSG(extack, "Unsupported XFRM mode for IPcomp"); 155 goto out; 156 } 157 158 err = ipcomp_init_state(x, extack); 159 if (err) 160 goto out; 161 162 if (x->props.mode == XFRM_MODE_TUNNEL) { 163 err = ipcomp6_tunnel_attach(x); 164 if (err) { 165 NL_SET_ERR_MSG(extack, "Kernel error: failed to initialize the associated state"); 166 goto out; 167 } 168 } 169 170 err = 0; 171 out: 172 return err; 173 } 174 175 static int ipcomp6_rcv_cb(struct sk_buff *skb, int err) 176 { 177 return 0; 178 } 179 180 static const struct xfrm_type ipcomp6_type = { 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 }; 188 189 static struct xfrm6_protocol ipcomp6_protocol = { 190 .handler = xfrm6_rcv, 191 .input_handler = xfrm_input, 192 .cb_handler = ipcomp6_rcv_cb, 193 .err_handler = ipcomp6_err, 194 .priority = 0, 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 (xfrm6_protocol_register(&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 (xfrm6_protocol_deregister(&ipcomp6_protocol, IPPROTO_COMP) < 0) 214 pr_info("%s: can't remove protocol\n", __func__); 215 xfrm_unregister_type(&ipcomp6_type, AF_INET6); 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