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