11da177e4SLinus Torvalds /* 21da177e4SLinus Torvalds * xfrm4_policy.c 31da177e4SLinus Torvalds * 41da177e4SLinus Torvalds * Changes: 51da177e4SLinus Torvalds * Kazunori MIYAZAWA @USAGI 61da177e4SLinus Torvalds * YOSHIFUJI Hideaki @USAGI 71da177e4SLinus Torvalds * Split up af-specific portion 81da177e4SLinus Torvalds * 91da177e4SLinus Torvalds */ 101da177e4SLinus Torvalds 1166cdb3caSHerbert Xu #include <linux/err.h> 1266cdb3caSHerbert Xu #include <linux/kernel.h> 13aabc9761SHerbert Xu #include <linux/inetdevice.h> 14cc9ff19dSTimo Teräs #include <linux/if_tunnel.h> 1545ff5a3fSHerbert Xu #include <net/dst.h> 161da177e4SLinus Torvalds #include <net/xfrm.h> 171da177e4SLinus Torvalds #include <net/ip.h> 181da177e4SLinus Torvalds 191da177e4SLinus Torvalds static struct xfrm_policy_afinfo xfrm4_policy_afinfo; 201da177e4SLinus Torvalds 21c5b3cf46SAlexey Dobriyan static struct dst_entry *xfrm4_dst_lookup(struct net *net, int tos, 225e6b930fSDavid S. Miller const xfrm_address_t *saddr, 235e6b930fSDavid S. Miller const xfrm_address_t *daddr) 241da177e4SLinus Torvalds { 259d6ec938SDavid S. Miller struct flowi4 fl4 = { 269d6ec938SDavid S. Miller .daddr = daddr->a4, 279d6ec938SDavid S. Miller .flowi4_tos = tos, 28a1e59abfSPatrick McHardy }; 2966cdb3caSHerbert Xu struct rtable *rt; 30a1e59abfSPatrick McHardy 3166cdb3caSHerbert Xu if (saddr) 329d6ec938SDavid S. Miller fl4.saddr = saddr->a4; 3366cdb3caSHerbert Xu 349d6ec938SDavid S. Miller rt = __ip_route_output_key(net, &fl4); 35b23dd4feSDavid S. Miller if (!IS_ERR(rt)) 36b23dd4feSDavid S. Miller return &rt->dst; 37b23dd4feSDavid S. Miller 38b23dd4feSDavid S. Miller return ERR_CAST(rt); 39a1e59abfSPatrick McHardy } 4066cdb3caSHerbert Xu 41fbda33b2SAlexey Dobriyan static int xfrm4_get_saddr(struct net *net, 42fbda33b2SAlexey Dobriyan xfrm_address_t *saddr, xfrm_address_t *daddr) 4366cdb3caSHerbert Xu { 4466cdb3caSHerbert Xu struct dst_entry *dst; 4566cdb3caSHerbert Xu struct rtable *rt; 4666cdb3caSHerbert Xu 47fbda33b2SAlexey Dobriyan dst = xfrm4_dst_lookup(net, 0, NULL, daddr); 4866cdb3caSHerbert Xu if (IS_ERR(dst)) 49a1e59abfSPatrick McHardy return -EHOSTUNREACH; 5066cdb3caSHerbert Xu 5166cdb3caSHerbert Xu rt = (struct rtable *)dst; 5266cdb3caSHerbert Xu saddr->a4 = rt->rt_src; 5366cdb3caSHerbert Xu dst_release(dst); 5466cdb3caSHerbert Xu return 0; 55a1e59abfSPatrick McHardy } 56a1e59abfSPatrick McHardy 5705d84025SDavid S. Miller static int xfrm4_get_tos(const struct flowi *fl) 581da177e4SLinus Torvalds { 597e1dc7b6SDavid S. Miller return IPTOS_RT_MASK & fl->u.ip4.flowi4_tos; /* Strip ECN bits */ 601da177e4SLinus Torvalds } 611da177e4SLinus Torvalds 62a1b05140SMasahide NAKAMURA static int xfrm4_init_path(struct xfrm_dst *path, struct dst_entry *dst, 63a1b05140SMasahide NAKAMURA int nfheader_len) 64a1b05140SMasahide NAKAMURA { 65a1b05140SMasahide NAKAMURA return 0; 66a1b05140SMasahide NAKAMURA } 67a1b05140SMasahide NAKAMURA 6887c1e12bSHerbert Xu static int xfrm4_fill_dst(struct xfrm_dst *xdst, struct net_device *dev, 690c7b3eefSDavid S. Miller const struct flowi *fl) 7025ee3286SHerbert Xu { 7125ee3286SHerbert Xu struct rtable *rt = (struct rtable *)xdst->route; 727e1dc7b6SDavid S. Miller const struct flowi4 *fl4 = &fl->u.ip4; 731da177e4SLinus Torvalds 747e1dc7b6SDavid S. Miller rt->rt_key_dst = fl4->daddr; 757e1dc7b6SDavid S. Miller rt->rt_key_src = fl4->saddr; 767e1dc7b6SDavid S. Miller rt->rt_tos = fl4->flowi4_tos; 777e1dc7b6SDavid S. Miller rt->rt_iif = fl4->flowi4_iif; 787e1dc7b6SDavid S. Miller rt->rt_oif = fl4->flowi4_oif; 797e1dc7b6SDavid S. Miller rt->rt_mark = fl4->flowi4_mark; 801da177e4SLinus Torvalds 8125ee3286SHerbert Xu xdst->u.dst.dev = dev; 8225ee3286SHerbert Xu dev_hold(dev); 8343372262SMiika Komu 8425ee3286SHerbert Xu xdst->u.rt.peer = rt->peer; 8525ee3286SHerbert Xu if (rt->peer) 8625ee3286SHerbert Xu atomic_inc(&rt->peer->refcnt); 8766cdb3caSHerbert Xu 881da177e4SLinus Torvalds /* Sheit... I remember I did this right. Apparently, 891da177e4SLinus Torvalds * it was magically lost, so this code needs audit */ 9025ee3286SHerbert Xu xdst->u.rt.rt_flags = rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST | 9125ee3286SHerbert Xu RTCF_LOCAL); 9225ee3286SHerbert Xu xdst->u.rt.rt_type = rt->rt_type; 9325ee3286SHerbert Xu xdst->u.rt.rt_src = rt->rt_src; 9425ee3286SHerbert Xu xdst->u.rt.rt_dst = rt->rt_dst; 9525ee3286SHerbert Xu xdst->u.rt.rt_gateway = rt->rt_gateway; 9625ee3286SHerbert Xu xdst->u.rt.rt_spec_dst = rt->rt_spec_dst; 971da177e4SLinus Torvalds 981da177e4SLinus Torvalds return 0; 991da177e4SLinus Torvalds } 1001da177e4SLinus Torvalds 1011da177e4SLinus Torvalds static void 102d5422efeSHerbert Xu _decode_session4(struct sk_buff *skb, struct flowi *fl, int reverse) 1031da177e4SLinus Torvalds { 104eddc9ec5SArnaldo Carvalho de Melo struct iphdr *iph = ip_hdr(skb); 105d56f90a7SArnaldo Carvalho de Melo u8 *xprth = skb_network_header(skb) + iph->ihl * 4; 1067e1dc7b6SDavid S. Miller struct flowi4 *fl4 = &fl->u.ip4; 1071da177e4SLinus Torvalds 1087e1dc7b6SDavid S. Miller memset(fl4, 0, sizeof(struct flowi4)); 1097e1dc7b6SDavid S. Miller fl4->flowi4_mark = skb->mark; 11044b451f1SPeter Kosyh 1111da177e4SLinus Torvalds if (!(iph->frag_off & htons(IP_MF | IP_OFFSET))) { 1121da177e4SLinus Torvalds switch (iph->protocol) { 1131da177e4SLinus Torvalds case IPPROTO_UDP: 114ba4e58ecSGerrit Renker case IPPROTO_UDPLITE: 1151da177e4SLinus Torvalds case IPPROTO_TCP: 1161da177e4SLinus Torvalds case IPPROTO_SCTP: 1179e999993SPatrick McHardy case IPPROTO_DCCP: 118c615c9f3SWei Yongjun if (xprth + 4 < skb->data || 119c615c9f3SWei Yongjun pskb_may_pull(skb, xprth + 4 - skb->data)) { 1208c689a6eSAl Viro __be16 *ports = (__be16 *)xprth; 1211da177e4SLinus Torvalds 122*9cce96dfSDavid S. Miller fl4->fl4_sport = ports[!!reverse]; 123*9cce96dfSDavid S. Miller fl4->fl4_dport = ports[!reverse]; 1241da177e4SLinus Torvalds } 1251da177e4SLinus Torvalds break; 1261da177e4SLinus Torvalds 1271da177e4SLinus Torvalds case IPPROTO_ICMP: 1281da177e4SLinus Torvalds if (pskb_may_pull(skb, xprth + 2 - skb->data)) { 1291da177e4SLinus Torvalds u8 *icmp = xprth; 1301da177e4SLinus Torvalds 131*9cce96dfSDavid S. Miller fl4->fl4_icmp_type = icmp[0]; 132*9cce96dfSDavid S. Miller fl4->fl4_icmp_code = icmp[1]; 1331da177e4SLinus Torvalds } 1341da177e4SLinus Torvalds break; 1351da177e4SLinus Torvalds 1361da177e4SLinus Torvalds case IPPROTO_ESP: 1371da177e4SLinus Torvalds if (pskb_may_pull(skb, xprth + 4 - skb->data)) { 1384324a174SAl Viro __be32 *ehdr = (__be32 *)xprth; 1391da177e4SLinus Torvalds 140*9cce96dfSDavid S. Miller fl4->fl4_ipsec_spi = ehdr[0]; 1411da177e4SLinus Torvalds } 1421da177e4SLinus Torvalds break; 1431da177e4SLinus Torvalds 1441da177e4SLinus Torvalds case IPPROTO_AH: 1451da177e4SLinus Torvalds if (pskb_may_pull(skb, xprth + 8 - skb->data)) { 1464324a174SAl Viro __be32 *ah_hdr = (__be32*)xprth; 1471da177e4SLinus Torvalds 148*9cce96dfSDavid S. Miller fl4->fl4_ipsec_spi = ah_hdr[1]; 1491da177e4SLinus Torvalds } 1501da177e4SLinus Torvalds break; 1511da177e4SLinus Torvalds 1521da177e4SLinus Torvalds case IPPROTO_COMP: 1531da177e4SLinus Torvalds if (pskb_may_pull(skb, xprth + 4 - skb->data)) { 1544324a174SAl Viro __be16 *ipcomp_hdr = (__be16 *)xprth; 1551da177e4SLinus Torvalds 156*9cce96dfSDavid S. Miller fl4->fl4_ipsec_spi = htonl(ntohs(ipcomp_hdr[1])); 1571da177e4SLinus Torvalds } 1581da177e4SLinus Torvalds break; 159cc9ff19dSTimo Teräs 160cc9ff19dSTimo Teräs case IPPROTO_GRE: 161cc9ff19dSTimo Teräs if (pskb_may_pull(skb, xprth + 12 - skb->data)) { 162cc9ff19dSTimo Teräs __be16 *greflags = (__be16 *)xprth; 163cc9ff19dSTimo Teräs __be32 *gre_hdr = (__be32 *)xprth; 164cc9ff19dSTimo Teräs 165cc9ff19dSTimo Teräs if (greflags[0] & GRE_KEY) { 166cc9ff19dSTimo Teräs if (greflags[0] & GRE_CSUM) 167cc9ff19dSTimo Teräs gre_hdr++; 168*9cce96dfSDavid S. Miller fl4->fl4_gre_key = gre_hdr[1]; 169cc9ff19dSTimo Teräs } 170cc9ff19dSTimo Teräs } 171cc9ff19dSTimo Teräs break; 172cc9ff19dSTimo Teräs 1731da177e4SLinus Torvalds default: 174*9cce96dfSDavid S. Miller fl4->fl4_ipsec_spi = 0; 1751da177e4SLinus Torvalds break; 1763ff50b79SStephen Hemminger } 1771da177e4SLinus Torvalds } 1787e1dc7b6SDavid S. Miller fl4->flowi4_proto = iph->protocol; 1797e1dc7b6SDavid S. Miller fl4->daddr = reverse ? iph->saddr : iph->daddr; 1807e1dc7b6SDavid S. Miller fl4->saddr = reverse ? iph->daddr : iph->saddr; 1817e1dc7b6SDavid S. Miller fl4->flowi4_tos = iph->tos; 1821da177e4SLinus Torvalds } 1831da177e4SLinus Torvalds 184569d3645SDaniel Lezcano static inline int xfrm4_garbage_collect(struct dst_ops *ops) 1851da177e4SLinus Torvalds { 186d7c7544cSAlexey Dobriyan struct net *net = container_of(ops, struct net, xfrm.xfrm4_dst_ops); 187d7c7544cSAlexey Dobriyan 188d7c7544cSAlexey Dobriyan xfrm4_policy_afinfo.garbage_collect(net); 189fc66f95cSEric Dumazet return (dst_entries_get_slow(ops) > ops->gc_thresh * 2); 1901da177e4SLinus Torvalds } 1911da177e4SLinus Torvalds 1921da177e4SLinus Torvalds static void xfrm4_update_pmtu(struct dst_entry *dst, u32 mtu) 1931da177e4SLinus Torvalds { 1941da177e4SLinus Torvalds struct xfrm_dst *xdst = (struct xfrm_dst *)dst; 1951da177e4SLinus Torvalds struct dst_entry *path = xdst->route; 1961da177e4SLinus Torvalds 1971da177e4SLinus Torvalds path->ops->update_pmtu(path, mtu); 1981da177e4SLinus Torvalds } 1991da177e4SLinus Torvalds 200aabc9761SHerbert Xu static void xfrm4_dst_destroy(struct dst_entry *dst) 201aabc9761SHerbert Xu { 202aabc9761SHerbert Xu struct xfrm_dst *xdst = (struct xfrm_dst *)dst; 203aabc9761SHerbert Xu 20462fa8a84SDavid S. Miller dst_destroy_metrics_generic(dst); 20562fa8a84SDavid S. Miller 206ed3e37ddSHerbert Xu if (likely(xdst->u.rt.peer)) 20726db1677SDavid S. Miller inet_putpeer(xdst->u.rt.peer); 20862fa8a84SDavid S. Miller 209aabc9761SHerbert Xu xfrm_dst_destroy(xdst); 210aabc9761SHerbert Xu } 211aabc9761SHerbert Xu 212aabc9761SHerbert Xu static void xfrm4_dst_ifdown(struct dst_entry *dst, struct net_device *dev, 213aabc9761SHerbert Xu int unregister) 214aabc9761SHerbert Xu { 215aabc9761SHerbert Xu if (!unregister) 216aabc9761SHerbert Xu return; 217aabc9761SHerbert Xu 218aabc9761SHerbert Xu xfrm_dst_ifdown(dst, dev); 219aabc9761SHerbert Xu } 220aabc9761SHerbert Xu 2211da177e4SLinus Torvalds static struct dst_ops xfrm4_dst_ops = { 2221da177e4SLinus Torvalds .family = AF_INET, 22309640e63SHarvey Harrison .protocol = cpu_to_be16(ETH_P_IP), 2241da177e4SLinus Torvalds .gc = xfrm4_garbage_collect, 2251da177e4SLinus Torvalds .update_pmtu = xfrm4_update_pmtu, 22662fa8a84SDavid S. Miller .cow_metrics = dst_cow_metrics_generic, 227aabc9761SHerbert Xu .destroy = xfrm4_dst_destroy, 228aabc9761SHerbert Xu .ifdown = xfrm4_dst_ifdown, 229862b82c6SHerbert Xu .local_out = __ip_local_out, 2301da177e4SLinus Torvalds .gc_thresh = 1024, 2311da177e4SLinus Torvalds }; 2321da177e4SLinus Torvalds 2331da177e4SLinus Torvalds static struct xfrm_policy_afinfo xfrm4_policy_afinfo = { 2341da177e4SLinus Torvalds .family = AF_INET, 2351da177e4SLinus Torvalds .dst_ops = &xfrm4_dst_ops, 2361da177e4SLinus Torvalds .dst_lookup = xfrm4_dst_lookup, 237a1e59abfSPatrick McHardy .get_saddr = xfrm4_get_saddr, 2381da177e4SLinus Torvalds .decode_session = _decode_session4, 23925ee3286SHerbert Xu .get_tos = xfrm4_get_tos, 240a1b05140SMasahide NAKAMURA .init_path = xfrm4_init_path, 24125ee3286SHerbert Xu .fill_dst = xfrm4_fill_dst, 2422774c131SDavid S. Miller .blackhole_route = ipv4_blackhole_route, 2431da177e4SLinus Torvalds }; 2441da177e4SLinus Torvalds 245f816700aSRandy Dunlap #ifdef CONFIG_SYSCTL 246a44a4a00SNeil Horman static struct ctl_table xfrm4_policy_table[] = { 247a44a4a00SNeil Horman { 248a44a4a00SNeil Horman .procname = "xfrm4_gc_thresh", 249d7c7544cSAlexey Dobriyan .data = &init_net.xfrm.xfrm4_dst_ops.gc_thresh, 250a44a4a00SNeil Horman .maxlen = sizeof(int), 251a44a4a00SNeil Horman .mode = 0644, 252a44a4a00SNeil Horman .proc_handler = proc_dointvec, 253a44a4a00SNeil Horman }, 254a44a4a00SNeil Horman { } 255a44a4a00SNeil Horman }; 256a44a4a00SNeil Horman 257a44a4a00SNeil Horman static struct ctl_table_header *sysctl_hdr; 258f816700aSRandy Dunlap #endif 259a44a4a00SNeil Horman 2601da177e4SLinus Torvalds static void __init xfrm4_policy_init(void) 2611da177e4SLinus Torvalds { 2621da177e4SLinus Torvalds xfrm_policy_register_afinfo(&xfrm4_policy_afinfo); 2631da177e4SLinus Torvalds } 2641da177e4SLinus Torvalds 2651da177e4SLinus Torvalds static void __exit xfrm4_policy_fini(void) 2661da177e4SLinus Torvalds { 267f816700aSRandy Dunlap #ifdef CONFIG_SYSCTL 268a44a4a00SNeil Horman if (sysctl_hdr) 269a44a4a00SNeil Horman unregister_net_sysctl_table(sysctl_hdr); 270f816700aSRandy Dunlap #endif 2711da177e4SLinus Torvalds xfrm_policy_unregister_afinfo(&xfrm4_policy_afinfo); 2721da177e4SLinus Torvalds } 2731da177e4SLinus Torvalds 274a33bc5c1SNeil Horman void __init xfrm4_init(int rt_max_size) 2751da177e4SLinus Torvalds { 276a33bc5c1SNeil Horman /* 277a33bc5c1SNeil Horman * Select a default value for the gc_thresh based on the main route 278a33bc5c1SNeil Horman * table hash size. It seems to me the worst case scenario is when 279a33bc5c1SNeil Horman * we have ipsec operating in transport mode, in which we create a 280a33bc5c1SNeil Horman * dst_entry per socket. The xfrm gc algorithm starts trying to remove 281a33bc5c1SNeil Horman * entries at gc_thresh, and prevents new allocations as 2*gc_thresh 282a33bc5c1SNeil Horman * so lets set an initial xfrm gc_thresh value at the rt_max_size/2. 283a33bc5c1SNeil Horman * That will let us store an ipsec connection per route table entry, 284a33bc5c1SNeil Horman * and start cleaning when were 1/2 full 285a33bc5c1SNeil Horman */ 286a33bc5c1SNeil Horman xfrm4_dst_ops.gc_thresh = rt_max_size/2; 287fc66f95cSEric Dumazet dst_entries_init(&xfrm4_dst_ops); 288d7c7544cSAlexey Dobriyan 289d7c7544cSAlexey Dobriyan xfrm4_state_init(); 290d7c7544cSAlexey Dobriyan xfrm4_policy_init(); 291f816700aSRandy Dunlap #ifdef CONFIG_SYSCTL 292a44a4a00SNeil Horman sysctl_hdr = register_net_sysctl_table(&init_net, net_ipv4_ctl_path, 293a44a4a00SNeil Horman xfrm4_policy_table); 294f816700aSRandy Dunlap #endif 2951da177e4SLinus Torvalds } 2961da177e4SLinus Torvalds 297