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; 107 108 memset(fl4, 0, sizeof(struct flowi4)); 109 fl4->flowi4_mark = skb->mark; 110 111 if (!ip_is_fragment(iph)) { 112 switch (iph->protocol) { 113 case IPPROTO_UDP: 114 case IPPROTO_UDPLITE: 115 case IPPROTO_TCP: 116 case IPPROTO_SCTP: 117 case IPPROTO_DCCP: 118 if (xprth + 4 < skb->data || 119 pskb_may_pull(skb, xprth + 4 - skb->data)) { 120 __be16 *ports = (__be16 *)xprth; 121 122 fl4->fl4_sport = ports[!!reverse]; 123 fl4->fl4_dport = ports[!reverse]; 124 } 125 break; 126 127 case IPPROTO_ICMP: 128 if (pskb_may_pull(skb, xprth + 2 - skb->data)) { 129 u8 *icmp = xprth; 130 131 fl4->fl4_icmp_type = icmp[0]; 132 fl4->fl4_icmp_code = icmp[1]; 133 } 134 break; 135 136 case IPPROTO_ESP: 137 if (pskb_may_pull(skb, xprth + 4 - skb->data)) { 138 __be32 *ehdr = (__be32 *)xprth; 139 140 fl4->fl4_ipsec_spi = ehdr[0]; 141 } 142 break; 143 144 case IPPROTO_AH: 145 if (pskb_may_pull(skb, xprth + 8 - skb->data)) { 146 __be32 *ah_hdr = (__be32 *)xprth; 147 148 fl4->fl4_ipsec_spi = ah_hdr[1]; 149 } 150 break; 151 152 case IPPROTO_COMP: 153 if (pskb_may_pull(skb, xprth + 4 - skb->data)) { 154 __be16 *ipcomp_hdr = (__be16 *)xprth; 155 156 fl4->fl4_ipsec_spi = htonl(ntohs(ipcomp_hdr[1])); 157 } 158 break; 159 160 case IPPROTO_GRE: 161 if (pskb_may_pull(skb, xprth + 12 - skb->data)) { 162 __be16 *greflags = (__be16 *)xprth; 163 __be32 *gre_hdr = (__be32 *)xprth; 164 165 if (greflags[0] & GRE_KEY) { 166 if (greflags[0] & GRE_CSUM) 167 gre_hdr++; 168 fl4->fl4_gre_key = gre_hdr[1]; 169 } 170 } 171 break; 172 173 default: 174 fl4->fl4_ipsec_spi = 0; 175 break; 176 } 177 } 178 fl4->flowi4_proto = iph->protocol; 179 fl4->daddr = reverse ? iph->saddr : iph->daddr; 180 fl4->saddr = reverse ? iph->daddr : iph->saddr; 181 fl4->flowi4_tos = iph->tos; 182 } 183 184 static inline int xfrm4_garbage_collect(struct dst_ops *ops) 185 { 186 struct net *net = container_of(ops, struct net, xfrm.xfrm4_dst_ops); 187 188 xfrm4_policy_afinfo.garbage_collect(net); 189 return (dst_entries_get_slow(ops) > ops->gc_thresh * 2); 190 } 191 192 static void xfrm4_update_pmtu(struct dst_entry *dst, struct sock *sk, 193 struct sk_buff *skb, u32 mtu) 194 { 195 struct xfrm_dst *xdst = (struct xfrm_dst *)dst; 196 struct dst_entry *path = xdst->route; 197 198 path->ops->update_pmtu(path, sk, skb, mtu); 199 } 200 201 static void xfrm4_redirect(struct dst_entry *dst, struct sock *sk, 202 struct sk_buff *skb) 203 { 204 struct xfrm_dst *xdst = (struct xfrm_dst *)dst; 205 struct dst_entry *path = xdst->route; 206 207 path->ops->redirect(path, sk, skb); 208 } 209 210 static void xfrm4_dst_destroy(struct dst_entry *dst) 211 { 212 struct xfrm_dst *xdst = (struct xfrm_dst *)dst; 213 214 dst_destroy_metrics_generic(dst); 215 216 xfrm_dst_destroy(xdst); 217 } 218 219 static void xfrm4_dst_ifdown(struct dst_entry *dst, struct net_device *dev, 220 int unregister) 221 { 222 if (!unregister) 223 return; 224 225 xfrm_dst_ifdown(dst, dev); 226 } 227 228 static struct dst_ops xfrm4_dst_ops = { 229 .family = AF_INET, 230 .protocol = cpu_to_be16(ETH_P_IP), 231 .gc = xfrm4_garbage_collect, 232 .update_pmtu = xfrm4_update_pmtu, 233 .redirect = xfrm4_redirect, 234 .cow_metrics = dst_cow_metrics_generic, 235 .destroy = xfrm4_dst_destroy, 236 .ifdown = xfrm4_dst_ifdown, 237 .local_out = __ip_local_out, 238 .gc_thresh = 1024, 239 }; 240 241 static struct xfrm_policy_afinfo xfrm4_policy_afinfo = { 242 .family = AF_INET, 243 .dst_ops = &xfrm4_dst_ops, 244 .dst_lookup = xfrm4_dst_lookup, 245 .get_saddr = xfrm4_get_saddr, 246 .decode_session = _decode_session4, 247 .get_tos = xfrm4_get_tos, 248 .init_path = xfrm4_init_path, 249 .fill_dst = xfrm4_fill_dst, 250 .blackhole_route = ipv4_blackhole_route, 251 }; 252 253 #ifdef CONFIG_SYSCTL 254 static struct ctl_table xfrm4_policy_table[] = { 255 { 256 .procname = "xfrm4_gc_thresh", 257 .data = &init_net.xfrm.xfrm4_dst_ops.gc_thresh, 258 .maxlen = sizeof(int), 259 .mode = 0644, 260 .proc_handler = proc_dointvec, 261 }, 262 { } 263 }; 264 265 static struct ctl_table_header *sysctl_hdr; 266 #endif 267 268 static void __init xfrm4_policy_init(void) 269 { 270 xfrm_policy_register_afinfo(&xfrm4_policy_afinfo); 271 } 272 273 static void __exit xfrm4_policy_fini(void) 274 { 275 #ifdef CONFIG_SYSCTL 276 if (sysctl_hdr) 277 unregister_net_sysctl_table(sysctl_hdr); 278 #endif 279 xfrm_policy_unregister_afinfo(&xfrm4_policy_afinfo); 280 } 281 282 void __init xfrm4_init(void) 283 { 284 dst_entries_init(&xfrm4_dst_ops); 285 286 xfrm4_state_init(); 287 xfrm4_policy_init(); 288 #ifdef CONFIG_SYSCTL 289 sysctl_hdr = register_net_sysctl(&init_net, "net/ipv4", 290 xfrm4_policy_table); 291 #endif 292 } 293 294