1 /* 2 * xfrm4_policy.c 3 * 4 * Changes: 5 * Kazunori MIYAZAWA @USAGI 6 * YOSHIFUJI Hideaki @USAGI 7 * Split up af-specific portion 8 * 9 */ 10 11 #include <linux/err.h> 12 #include <linux/kernel.h> 13 #include <linux/inetdevice.h> 14 #include <linux/if_tunnel.h> 15 #include <net/dst.h> 16 #include <net/xfrm.h> 17 #include <net/ip.h> 18 #include <net/vrf.h> 19 20 static struct xfrm_policy_afinfo xfrm4_policy_afinfo; 21 22 static struct dst_entry *__xfrm4_dst_lookup(struct net *net, struct flowi4 *fl4, 23 int tos, int oif, 24 const xfrm_address_t *saddr, 25 const xfrm_address_t *daddr) 26 { 27 struct rtable *rt; 28 29 memset(fl4, 0, sizeof(*fl4)); 30 fl4->daddr = daddr->a4; 31 fl4->flowi4_tos = tos; 32 fl4->flowi4_oif = oif; 33 if (saddr) 34 fl4->saddr = saddr->a4; 35 36 fl4->flowi4_flags = FLOWI_FLAG_SKIP_NH_OIF; 37 38 rt = __ip_route_output_key(net, fl4); 39 if (!IS_ERR(rt)) 40 return &rt->dst; 41 42 return ERR_CAST(rt); 43 } 44 45 static struct dst_entry *xfrm4_dst_lookup(struct net *net, int tos, int oif, 46 const xfrm_address_t *saddr, 47 const xfrm_address_t *daddr) 48 { 49 struct flowi4 fl4; 50 51 return __xfrm4_dst_lookup(net, &fl4, tos, oif, saddr, daddr); 52 } 53 54 static int xfrm4_get_saddr(struct net *net, int oif, 55 xfrm_address_t *saddr, xfrm_address_t *daddr) 56 { 57 struct dst_entry *dst; 58 struct flowi4 fl4; 59 60 dst = __xfrm4_dst_lookup(net, &fl4, 0, oif, NULL, daddr); 61 if (IS_ERR(dst)) 62 return -EHOSTUNREACH; 63 64 saddr->a4 = fl4.saddr; 65 dst_release(dst); 66 return 0; 67 } 68 69 static int xfrm4_get_tos(const struct flowi *fl) 70 { 71 return IPTOS_RT_MASK & fl->u.ip4.flowi4_tos; /* Strip ECN bits */ 72 } 73 74 static int xfrm4_init_path(struct xfrm_dst *path, struct dst_entry *dst, 75 int nfheader_len) 76 { 77 return 0; 78 } 79 80 static int xfrm4_fill_dst(struct xfrm_dst *xdst, struct net_device *dev, 81 const struct flowi *fl) 82 { 83 struct rtable *rt = (struct rtable *)xdst->route; 84 const struct flowi4 *fl4 = &fl->u.ip4; 85 86 xdst->u.rt.rt_iif = fl4->flowi4_iif; 87 88 xdst->u.dst.dev = dev; 89 dev_hold(dev); 90 91 /* Sheit... I remember I did this right. Apparently, 92 * it was magically lost, so this code needs audit */ 93 xdst->u.rt.rt_is_input = rt->rt_is_input; 94 xdst->u.rt.rt_flags = rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST | 95 RTCF_LOCAL); 96 xdst->u.rt.rt_type = rt->rt_type; 97 xdst->u.rt.rt_gateway = rt->rt_gateway; 98 xdst->u.rt.rt_uses_gateway = rt->rt_uses_gateway; 99 xdst->u.rt.rt_pmtu = rt->rt_pmtu; 100 INIT_LIST_HEAD(&xdst->u.rt.rt_uncached); 101 102 return 0; 103 } 104 105 static void 106 _decode_session4(struct sk_buff *skb, struct flowi *fl, int reverse) 107 { 108 const struct iphdr *iph = ip_hdr(skb); 109 u8 *xprth = skb_network_header(skb) + iph->ihl * 4; 110 struct flowi4 *fl4 = &fl->u.ip4; 111 int oif = 0; 112 113 if (skb_dst(skb)) { 114 oif = vrf_master_ifindex(skb_dst(skb)->dev) ? 115 : skb_dst(skb)->dev->ifindex; 116 } 117 118 memset(fl4, 0, sizeof(struct flowi4)); 119 fl4->flowi4_mark = skb->mark; 120 fl4->flowi4_oif = reverse ? skb->skb_iif : oif; 121 122 if (!ip_is_fragment(iph)) { 123 switch (iph->protocol) { 124 case IPPROTO_UDP: 125 case IPPROTO_UDPLITE: 126 case IPPROTO_TCP: 127 case IPPROTO_SCTP: 128 case IPPROTO_DCCP: 129 if (xprth + 4 < skb->data || 130 pskb_may_pull(skb, xprth + 4 - skb->data)) { 131 __be16 *ports = (__be16 *)xprth; 132 133 fl4->fl4_sport = ports[!!reverse]; 134 fl4->fl4_dport = ports[!reverse]; 135 } 136 break; 137 138 case IPPROTO_ICMP: 139 if (pskb_may_pull(skb, xprth + 2 - skb->data)) { 140 u8 *icmp = xprth; 141 142 fl4->fl4_icmp_type = icmp[0]; 143 fl4->fl4_icmp_code = icmp[1]; 144 } 145 break; 146 147 case IPPROTO_ESP: 148 if (pskb_may_pull(skb, xprth + 4 - skb->data)) { 149 __be32 *ehdr = (__be32 *)xprth; 150 151 fl4->fl4_ipsec_spi = ehdr[0]; 152 } 153 break; 154 155 case IPPROTO_AH: 156 if (pskb_may_pull(skb, xprth + 8 - skb->data)) { 157 __be32 *ah_hdr = (__be32 *)xprth; 158 159 fl4->fl4_ipsec_spi = ah_hdr[1]; 160 } 161 break; 162 163 case IPPROTO_COMP: 164 if (pskb_may_pull(skb, xprth + 4 - skb->data)) { 165 __be16 *ipcomp_hdr = (__be16 *)xprth; 166 167 fl4->fl4_ipsec_spi = htonl(ntohs(ipcomp_hdr[1])); 168 } 169 break; 170 171 case IPPROTO_GRE: 172 if (pskb_may_pull(skb, xprth + 12 - skb->data)) { 173 __be16 *greflags = (__be16 *)xprth; 174 __be32 *gre_hdr = (__be32 *)xprth; 175 176 if (greflags[0] & GRE_KEY) { 177 if (greflags[0] & GRE_CSUM) 178 gre_hdr++; 179 fl4->fl4_gre_key = gre_hdr[1]; 180 } 181 } 182 break; 183 184 default: 185 fl4->fl4_ipsec_spi = 0; 186 break; 187 } 188 } 189 fl4->flowi4_proto = iph->protocol; 190 fl4->daddr = reverse ? iph->saddr : iph->daddr; 191 fl4->saddr = reverse ? iph->daddr : iph->saddr; 192 fl4->flowi4_tos = iph->tos; 193 } 194 195 static inline int xfrm4_garbage_collect(struct dst_ops *ops) 196 { 197 struct net *net = container_of(ops, struct net, xfrm.xfrm4_dst_ops); 198 199 xfrm4_policy_afinfo.garbage_collect(net); 200 return (dst_entries_get_slow(ops) > ops->gc_thresh * 2); 201 } 202 203 static void xfrm4_update_pmtu(struct dst_entry *dst, struct sock *sk, 204 struct sk_buff *skb, u32 mtu) 205 { 206 struct xfrm_dst *xdst = (struct xfrm_dst *)dst; 207 struct dst_entry *path = xdst->route; 208 209 path->ops->update_pmtu(path, sk, skb, mtu); 210 } 211 212 static void xfrm4_redirect(struct dst_entry *dst, struct sock *sk, 213 struct sk_buff *skb) 214 { 215 struct xfrm_dst *xdst = (struct xfrm_dst *)dst; 216 struct dst_entry *path = xdst->route; 217 218 path->ops->redirect(path, sk, skb); 219 } 220 221 static void xfrm4_dst_destroy(struct dst_entry *dst) 222 { 223 struct xfrm_dst *xdst = (struct xfrm_dst *)dst; 224 225 dst_destroy_metrics_generic(dst); 226 227 xfrm_dst_destroy(xdst); 228 } 229 230 static void xfrm4_dst_ifdown(struct dst_entry *dst, struct net_device *dev, 231 int unregister) 232 { 233 if (!unregister) 234 return; 235 236 xfrm_dst_ifdown(dst, dev); 237 } 238 239 static struct dst_ops xfrm4_dst_ops = { 240 .family = AF_INET, 241 .gc = xfrm4_garbage_collect, 242 .update_pmtu = xfrm4_update_pmtu, 243 .redirect = xfrm4_redirect, 244 .cow_metrics = dst_cow_metrics_generic, 245 .destroy = xfrm4_dst_destroy, 246 .ifdown = xfrm4_dst_ifdown, 247 .local_out = __ip_local_out, 248 .gc_thresh = 32768, 249 }; 250 251 static struct xfrm_policy_afinfo xfrm4_policy_afinfo = { 252 .family = AF_INET, 253 .dst_ops = &xfrm4_dst_ops, 254 .dst_lookup = xfrm4_dst_lookup, 255 .get_saddr = xfrm4_get_saddr, 256 .decode_session = _decode_session4, 257 .get_tos = xfrm4_get_tos, 258 .init_path = xfrm4_init_path, 259 .fill_dst = xfrm4_fill_dst, 260 .blackhole_route = ipv4_blackhole_route, 261 }; 262 263 #ifdef CONFIG_SYSCTL 264 static struct ctl_table xfrm4_policy_table[] = { 265 { 266 .procname = "xfrm4_gc_thresh", 267 .data = &init_net.xfrm.xfrm4_dst_ops.gc_thresh, 268 .maxlen = sizeof(int), 269 .mode = 0644, 270 .proc_handler = proc_dointvec, 271 }, 272 { } 273 }; 274 275 static int __net_init xfrm4_net_init(struct net *net) 276 { 277 struct ctl_table *table; 278 struct ctl_table_header *hdr; 279 280 table = xfrm4_policy_table; 281 if (!net_eq(net, &init_net)) { 282 table = kmemdup(table, sizeof(xfrm4_policy_table), GFP_KERNEL); 283 if (!table) 284 goto err_alloc; 285 286 table[0].data = &net->xfrm.xfrm4_dst_ops.gc_thresh; 287 } 288 289 hdr = register_net_sysctl(net, "net/ipv4", table); 290 if (!hdr) 291 goto err_reg; 292 293 net->ipv4.xfrm4_hdr = hdr; 294 return 0; 295 296 err_reg: 297 if (!net_eq(net, &init_net)) 298 kfree(table); 299 err_alloc: 300 return -ENOMEM; 301 } 302 303 static void __net_exit xfrm4_net_exit(struct net *net) 304 { 305 struct ctl_table *table; 306 307 if (!net->ipv4.xfrm4_hdr) 308 return; 309 310 table = net->ipv4.xfrm4_hdr->ctl_table_arg; 311 unregister_net_sysctl_table(net->ipv4.xfrm4_hdr); 312 if (!net_eq(net, &init_net)) 313 kfree(table); 314 } 315 316 static struct pernet_operations __net_initdata xfrm4_net_ops = { 317 .init = xfrm4_net_init, 318 .exit = xfrm4_net_exit, 319 }; 320 #endif 321 322 static void __init xfrm4_policy_init(void) 323 { 324 xfrm_policy_register_afinfo(&xfrm4_policy_afinfo); 325 } 326 327 void __init xfrm4_init(void) 328 { 329 dst_entries_init(&xfrm4_dst_ops); 330 331 xfrm4_state_init(); 332 xfrm4_policy_init(); 333 xfrm4_protocol_init(); 334 #ifdef CONFIG_SYSCTL 335 register_pernet_subsys(&xfrm4_net_ops); 336 #endif 337 } 338 339