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