/* * xfrm4_policy.c * * Changes: * Kazunori MIYAZAWA @USAGI * YOSHIFUJI Hideaki @USAGI * Split up af-specific portion * */ #include <linux/err.h> #include <linux/kernel.h> #include <linux/inetdevice.h> #include <net/dst.h> #include <net/xfrm.h> #include <net/ip.h> static struct xfrm_policy_afinfo xfrm4_policy_afinfo; static struct dst_entry *xfrm4_dst_lookup(struct net *net, int tos, xfrm_address_t *saddr, xfrm_address_t *daddr) { struct flowi fl = { .nl_u = { .ip4_u = { .tos = tos, .daddr = daddr->a4, }, }, }; struct dst_entry *dst; struct rtable *rt; int err; if (saddr) fl.fl4_src = saddr->a4; err = __ip_route_output_key(net, &rt, &fl); dst = &rt->u.dst; if (err) dst = ERR_PTR(err); return dst; } static int xfrm4_get_saddr(struct net *net, xfrm_address_t *saddr, xfrm_address_t *daddr) { struct dst_entry *dst; struct rtable *rt; dst = xfrm4_dst_lookup(net, 0, NULL, daddr); if (IS_ERR(dst)) return -EHOSTUNREACH; rt = (struct rtable *)dst; saddr->a4 = rt->rt_src; dst_release(dst); return 0; } static int xfrm4_get_tos(struct flowi *fl) { return fl->fl4_tos; } static int xfrm4_init_path(struct xfrm_dst *path, struct dst_entry *dst, int nfheader_len) { return 0; } static int xfrm4_fill_dst(struct xfrm_dst *xdst, struct net_device *dev, struct flowi *fl) { struct rtable *rt = (struct rtable *)xdst->route; xdst->u.rt.fl = *fl; xdst->u.dst.dev = dev; dev_hold(dev); xdst->u.rt.idev = in_dev_get(dev); if (!xdst->u.rt.idev) return -ENODEV; xdst->u.rt.peer = rt->peer; if (rt->peer) atomic_inc(&rt->peer->refcnt); /* Sheit... I remember I did this right. Apparently, * it was magically lost, so this code needs audit */ xdst->u.rt.rt_flags = rt->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST | RTCF_LOCAL); xdst->u.rt.rt_type = rt->rt_type; xdst->u.rt.rt_src = rt->rt_src; xdst->u.rt.rt_dst = rt->rt_dst; xdst->u.rt.rt_gateway = rt->rt_gateway; xdst->u.rt.rt_spec_dst = rt->rt_spec_dst; return 0; } static void _decode_session4(struct sk_buff *skb, struct flowi *fl, int reverse) { struct iphdr *iph = ip_hdr(skb); u8 *xprth = skb_network_header(skb) + iph->ihl * 4; memset(fl, 0, sizeof(struct flowi)); if (!(iph->frag_off & htons(IP_MF | IP_OFFSET))) { switch (iph->protocol) { case IPPROTO_UDP: case IPPROTO_UDPLITE: case IPPROTO_TCP: case IPPROTO_SCTP: case IPPROTO_DCCP: if (xprth + 4 < skb->data || pskb_may_pull(skb, xprth + 4 - skb->data)) { __be16 *ports = (__be16 *)xprth; fl->fl_ip_sport = ports[!!reverse]; fl->fl_ip_dport = ports[!reverse]; } break; case IPPROTO_ICMP: if (pskb_may_pull(skb, xprth + 2 - skb->data)) { u8 *icmp = xprth; fl->fl_icmp_type = icmp[0]; fl->fl_icmp_code = icmp[1]; } break; case IPPROTO_ESP: if (pskb_may_pull(skb, xprth + 4 - skb->data)) { __be32 *ehdr = (__be32 *)xprth; fl->fl_ipsec_spi = ehdr[0]; } break; case IPPROTO_AH: if (pskb_may_pull(skb, xprth + 8 - skb->data)) { __be32 *ah_hdr = (__be32*)xprth; fl->fl_ipsec_spi = ah_hdr[1]; } break; case IPPROTO_COMP: if (pskb_may_pull(skb, xprth + 4 - skb->data)) { __be16 *ipcomp_hdr = (__be16 *)xprth; fl->fl_ipsec_spi = htonl(ntohs(ipcomp_hdr[1])); } break; default: fl->fl_ipsec_spi = 0; break; } } fl->proto = iph->protocol; fl->fl4_dst = reverse ? iph->saddr : iph->daddr; fl->fl4_src = reverse ? iph->daddr : iph->saddr; fl->fl4_tos = iph->tos; } static inline int xfrm4_garbage_collect(struct dst_ops *ops) { struct net *net = container_of(ops, struct net, xfrm.xfrm4_dst_ops); xfrm4_policy_afinfo.garbage_collect(net); return (atomic_read(&ops->entries) > ops->gc_thresh * 2); } static void xfrm4_update_pmtu(struct dst_entry *dst, u32 mtu) { struct xfrm_dst *xdst = (struct xfrm_dst *)dst; struct dst_entry *path = xdst->route; path->ops->update_pmtu(path, mtu); } static void xfrm4_dst_destroy(struct dst_entry *dst) { struct xfrm_dst *xdst = (struct xfrm_dst *)dst; if (likely(xdst->u.rt.idev)) in_dev_put(xdst->u.rt.idev); if (likely(xdst->u.rt.peer)) inet_putpeer(xdst->u.rt.peer); xfrm_dst_destroy(xdst); } static void xfrm4_dst_ifdown(struct dst_entry *dst, struct net_device *dev, int unregister) { struct xfrm_dst *xdst; if (!unregister) return; xdst = (struct xfrm_dst *)dst; if (xdst->u.rt.idev->dev == dev) { struct in_device *loopback_idev = in_dev_get(dev_net(dev)->loopback_dev); BUG_ON(!loopback_idev); do { in_dev_put(xdst->u.rt.idev); xdst->u.rt.idev = loopback_idev; in_dev_hold(loopback_idev); xdst = (struct xfrm_dst *)xdst->u.dst.child; } while (xdst->u.dst.xfrm); __in_dev_put(loopback_idev); } xfrm_dst_ifdown(dst, dev); } static struct dst_ops xfrm4_dst_ops = { .family = AF_INET, .protocol = cpu_to_be16(ETH_P_IP), .gc = xfrm4_garbage_collect, .update_pmtu = xfrm4_update_pmtu, .destroy = xfrm4_dst_destroy, .ifdown = xfrm4_dst_ifdown, .local_out = __ip_local_out, .gc_thresh = 1024, .entries = ATOMIC_INIT(0), }; static struct xfrm_policy_afinfo xfrm4_policy_afinfo = { .family = AF_INET, .dst_ops = &xfrm4_dst_ops, .dst_lookup = xfrm4_dst_lookup, .get_saddr = xfrm4_get_saddr, .decode_session = _decode_session4, .get_tos = xfrm4_get_tos, .init_path = xfrm4_init_path, .fill_dst = xfrm4_fill_dst, }; #ifdef CONFIG_SYSCTL static struct ctl_table xfrm4_policy_table[] = { { .procname = "xfrm4_gc_thresh", .data = &init_net.xfrm.xfrm4_dst_ops.gc_thresh, .maxlen = sizeof(int), .mode = 0644, .proc_handler = proc_dointvec, }, { } }; static struct ctl_table_header *sysctl_hdr; #endif static void __init xfrm4_policy_init(void) { xfrm_policy_register_afinfo(&xfrm4_policy_afinfo); } static void __exit xfrm4_policy_fini(void) { #ifdef CONFIG_SYSCTL if (sysctl_hdr) unregister_net_sysctl_table(sysctl_hdr); #endif xfrm_policy_unregister_afinfo(&xfrm4_policy_afinfo); } void __init xfrm4_init(int rt_max_size) { /* * Select a default value for the gc_thresh based on the main route * table hash size. It seems to me the worst case scenario is when * we have ipsec operating in transport mode, in which we create a * dst_entry per socket. The xfrm gc algorithm starts trying to remove * entries at gc_thresh, and prevents new allocations as 2*gc_thresh * so lets set an initial xfrm gc_thresh value at the rt_max_size/2. * That will let us store an ipsec connection per route table entry, * and start cleaning when were 1/2 full */ xfrm4_dst_ops.gc_thresh = rt_max_size/2; xfrm4_state_init(); xfrm4_policy_init(); #ifdef CONFIG_SYSCTL sysctl_hdr = register_net_sysctl_table(&init_net, net_ipv4_ctl_path, xfrm4_policy_table); #endif }