| |
| /* (C) 1999-2001 Paul `Rusty' Russell |
| * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org> |
| * (C) 2006-2012 Patrick McHardy <kaber@trash.net> |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License version 2 as |
| * published by the Free Software Foundation. |
| */ |
| |
| #include <linux/types.h> |
| #include <linux/ip.h> |
| #include <linux/netfilter.h> |
| #include <linux/module.h> |
| #include <linux/skbuff.h> |
| #include <linux/icmp.h> |
| #include <linux/sysctl.h> |
| #include <net/route.h> |
| #include <net/ip.h> |
| |
| #include <linux/netfilter_ipv4.h> |
| #include <net/netfilter/nf_conntrack.h> |
| #include <net/netfilter/nf_conntrack_helper.h> |
| #include <net/netfilter/nf_conntrack_l4proto.h> |
| #include <net/netfilter/nf_conntrack_l3proto.h> |
| #include <net/netfilter/nf_conntrack_zones.h> |
| #include <net/netfilter/nf_conntrack_core.h> |
| #include <net/netfilter/ipv4/nf_conntrack_ipv4.h> |
| #include <net/netfilter/nf_nat_helper.h> |
| #include <net/netfilter/ipv4/nf_defrag_ipv4.h> |
| #include <net/netfilter/nf_log.h> |
| |
| static bool ipv4_pkt_to_tuple(const struct sk_buff *skb, unsigned int nhoff, |
| struct nf_conntrack_tuple *tuple) |
| { |
| const __be32 *ap; |
| __be32 _addrs[2]; |
| ap = skb_header_pointer(skb, nhoff + offsetof(struct iphdr, saddr), |
| sizeof(u_int32_t) * 2, _addrs); |
| if (ap == NULL) |
| return false; |
| |
| tuple->src.u3.ip = ap[0]; |
| tuple->dst.u3.ip = ap[1]; |
| |
| return true; |
| } |
| |
| static bool ipv4_invert_tuple(struct nf_conntrack_tuple *tuple, |
| const struct nf_conntrack_tuple *orig) |
| { |
| tuple->src.u3.ip = orig->dst.u3.ip; |
| tuple->dst.u3.ip = orig->src.u3.ip; |
| |
| return true; |
| } |
| |
| static int ipv4_print_tuple(struct seq_file *s, |
| const struct nf_conntrack_tuple *tuple) |
| { |
| return seq_printf(s, "src=%pI4 dst=%pI4 ", |
| &tuple->src.u3.ip, &tuple->dst.u3.ip); |
| } |
| |
| static int ipv4_get_l4proto(const struct sk_buff *skb, unsigned int nhoff, |
| unsigned int *dataoff, u_int8_t *protonum) |
| { |
| const struct iphdr *iph; |
| struct iphdr _iph; |
| |
| iph = skb_header_pointer(skb, nhoff, sizeof(_iph), &_iph); |
| if (iph == NULL) |
| return -NF_ACCEPT; |
| |
| /* Conntrack defragments packets, we might still see fragments |
| * inside ICMP packets though. */ |
| if (iph->frag_off & htons(IP_OFFSET)) |
| return -NF_ACCEPT; |
| |
| *dataoff = nhoff + (iph->ihl << 2); |
| *protonum = iph->protocol; |
| |
| /* Check bogus IP headers */ |
| if (*dataoff > skb->len) { |
| pr_debug("nf_conntrack_ipv4: bogus IPv4 packet: " |
| "nhoff %u, ihl %u, skblen %u\n", |
| nhoff, iph->ihl << 2, skb->len); |
| return -NF_ACCEPT; |
| } |
| |
| return NF_ACCEPT; |
| } |
| |
| static unsigned int ipv4_helper(unsigned int hooknum, |
| struct sk_buff *skb, |
| const struct net_device *in, |
| const struct net_device *out, |
| int (*okfn)(struct sk_buff *)) |
| { |
| struct nf_conn *ct; |
| enum ip_conntrack_info ctinfo; |
| const struct nf_conn_help *help; |
| const struct nf_conntrack_helper *helper; |
| |
| /* This is where we call the helper: as the packet goes out. */ |
| ct = nf_ct_get(skb, &ctinfo); |
| if (!ct || ctinfo == IP_CT_RELATED_REPLY) |
| return NF_ACCEPT; |
| |
| help = nfct_help(ct); |
| if (!help) |
| return NF_ACCEPT; |
| |
| /* rcu_read_lock()ed by nf_hook_slow */ |
| helper = rcu_dereference(help->helper); |
| if (!helper) |
| return NF_ACCEPT; |
| |
| return helper->help(skb, skb_network_offset(skb) + ip_hdrlen(skb), |
| ct, ctinfo); |
| } |
| |
| static unsigned int ipv4_confirm(unsigned int hooknum, |
| struct sk_buff *skb, |
| const struct net_device *in, |
| const struct net_device *out, |
| int (*okfn)(struct sk_buff *)) |
| { |
| struct nf_conn *ct; |
| enum ip_conntrack_info ctinfo; |
| |
| ct = nf_ct_get(skb, &ctinfo); |
| if (!ct || ctinfo == IP_CT_RELATED_REPLY) |
| goto out; |
| |
| /* adjust seqs for loopback traffic only in outgoing direction */ |
| if (test_bit(IPS_SEQ_ADJUST_BIT, &ct->status) && |
| !nf_is_loopback_packet(skb)) { |
| typeof(nf_nat_seq_adjust_hook) seq_adjust; |
| |
| seq_adjust = rcu_dereference(nf_nat_seq_adjust_hook); |
| if (!seq_adjust || |
| !seq_adjust(skb, ct, ctinfo, ip_hdrlen(skb))) { |
| NF_CT_STAT_INC_ATOMIC(nf_ct_net(ct), drop); |
| return NF_DROP; |
| } |
| } |
| out: |
| /* We've seen it coming out the other side: confirm it */ |
| return nf_conntrack_confirm(skb); |
| } |
| |
| static unsigned int ipv4_conntrack_in(unsigned int hooknum, |
| struct sk_buff *skb, |
| const struct net_device *in, |
| const struct net_device *out, |
| int (*okfn)(struct sk_buff *)) |
| { |
| return nf_conntrack_in(dev_net(in), PF_INET, hooknum, skb); |
| } |
| |
| static unsigned int ipv4_conntrack_local(unsigned int hooknum, |
| struct sk_buff *skb, |
| const struct net_device *in, |
| const struct net_device *out, |
| int (*okfn)(struct sk_buff *)) |
| { |
| /* root is playing with raw sockets. */ |
| if (skb->len < sizeof(struct iphdr) || |
| ip_hdrlen(skb) < sizeof(struct iphdr)) |
| return NF_ACCEPT; |
| return nf_conntrack_in(dev_net(out), PF_INET, hooknum, skb); |
| } |
| |
| /* Connection tracking may drop packets, but never alters them, so |
| make it the first hook. */ |
| static struct nf_hook_ops ipv4_conntrack_ops[] __read_mostly = { |
| { |
| .hook = ipv4_conntrack_in, |
| .owner = THIS_MODULE, |
| .pf = NFPROTO_IPV4, |
| .hooknum = NF_INET_PRE_ROUTING, |
| .priority = NF_IP_PRI_CONNTRACK, |
| }, |
| { |
| .hook = ipv4_conntrack_local, |
| .owner = THIS_MODULE, |
| .pf = NFPROTO_IPV4, |
| .hooknum = NF_INET_LOCAL_OUT, |
| .priority = NF_IP_PRI_CONNTRACK, |
| }, |
| { |
| .hook = ipv4_helper, |
| .owner = THIS_MODULE, |
| .pf = NFPROTO_IPV4, |
| .hooknum = NF_INET_POST_ROUTING, |
| .priority = NF_IP_PRI_CONNTRACK_HELPER, |
| }, |
| { |
| .hook = ipv4_confirm, |
| .owner = THIS_MODULE, |
| .pf = NFPROTO_IPV4, |
| .hooknum = NF_INET_POST_ROUTING, |
| .priority = NF_IP_PRI_CONNTRACK_CONFIRM, |
| }, |
| { |
| .hook = ipv4_helper, |
| .owner = THIS_MODULE, |
| .pf = NFPROTO_IPV4, |
| .hooknum = NF_INET_LOCAL_IN, |
| .priority = NF_IP_PRI_CONNTRACK_HELPER, |
| }, |
| { |
| .hook = ipv4_confirm, |
| .owner = THIS_MODULE, |
| .pf = NFPROTO_IPV4, |
| .hooknum = NF_INET_LOCAL_IN, |
| .priority = NF_IP_PRI_CONNTRACK_CONFIRM, |
| }, |
| }; |
| |
| #if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT) |
| static int log_invalid_proto_min = 0; |
| static int log_invalid_proto_max = 255; |
| |
| static ctl_table ip_ct_sysctl_table[] = { |
| { |
| .procname = "ip_conntrack_max", |
| .maxlen = sizeof(int), |
| .mode = 0644, |
| .proc_handler = proc_dointvec, |
| }, |
| { |
| .procname = "ip_conntrack_count", |
| .maxlen = sizeof(int), |
| .mode = 0444, |
| .proc_handler = proc_dointvec, |
| }, |
| { |
| .procname = "ip_conntrack_buckets", |
| .maxlen = sizeof(unsigned int), |
| .mode = 0444, |
| .proc_handler = proc_dointvec, |
| }, |
| { |
| .procname = "ip_conntrack_checksum", |
| .maxlen = sizeof(int), |
| .mode = 0644, |
| .proc_handler = proc_dointvec, |
| }, |
| { |
| .procname = "ip_conntrack_log_invalid", |
| .maxlen = sizeof(unsigned int), |
| .mode = 0644, |
| .proc_handler = proc_dointvec_minmax, |
| .extra1 = &log_invalid_proto_min, |
| .extra2 = &log_invalid_proto_max, |
| }, |
| { } |
| }; |
| #endif /* CONFIG_SYSCTL && CONFIG_NF_CONNTRACK_PROC_COMPAT */ |
| |
| /* Fast function for those who don't want to parse /proc (and I don't |
| blame them). */ |
| /* Reversing the socket's dst/src point of view gives us the reply |
| mapping. */ |
| static int |
| getorigdst(struct sock *sk, int optval, void __user *user, int *len) |
| { |
| const struct inet_sock *inet = inet_sk(sk); |
| const struct nf_conntrack_tuple_hash *h; |
| struct nf_conntrack_tuple tuple; |
| |
| memset(&tuple, 0, sizeof(tuple)); |
| tuple.src.u3.ip = inet->inet_rcv_saddr; |
| tuple.src.u.tcp.port = inet->inet_sport; |
| tuple.dst.u3.ip = inet->inet_daddr; |
| tuple.dst.u.tcp.port = inet->inet_dport; |
| tuple.src.l3num = PF_INET; |
| tuple.dst.protonum = sk->sk_protocol; |
| |
| /* We only do TCP and SCTP at the moment: is there a better way? */ |
| if (sk->sk_protocol != IPPROTO_TCP && sk->sk_protocol != IPPROTO_SCTP) { |
| pr_debug("SO_ORIGINAL_DST: Not a TCP/SCTP socket\n"); |
| return -ENOPROTOOPT; |
| } |
| |
| if ((unsigned int) *len < sizeof(struct sockaddr_in)) { |
| pr_debug("SO_ORIGINAL_DST: len %d not %Zu\n", |
| *len, sizeof(struct sockaddr_in)); |
| return -EINVAL; |
| } |
| |
| h = nf_conntrack_find_get(sock_net(sk), NF_CT_DEFAULT_ZONE, &tuple); |
| if (h) { |
| struct sockaddr_in sin; |
| struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h); |
| |
| sin.sin_family = AF_INET; |
| sin.sin_port = ct->tuplehash[IP_CT_DIR_ORIGINAL] |
| .tuple.dst.u.tcp.port; |
| sin.sin_addr.s_addr = ct->tuplehash[IP_CT_DIR_ORIGINAL] |
| .tuple.dst.u3.ip; |
| memset(sin.sin_zero, 0, sizeof(sin.sin_zero)); |
| |
| pr_debug("SO_ORIGINAL_DST: %pI4 %u\n", |
| &sin.sin_addr.s_addr, ntohs(sin.sin_port)); |
| nf_ct_put(ct); |
| if (copy_to_user(user, &sin, sizeof(sin)) != 0) |
| return -EFAULT; |
| else |
| return 0; |
| } |
| pr_debug("SO_ORIGINAL_DST: Can't find %pI4/%u-%pI4/%u.\n", |
| &tuple.src.u3.ip, ntohs(tuple.src.u.tcp.port), |
| &tuple.dst.u3.ip, ntohs(tuple.dst.u.tcp.port)); |
| return -ENOENT; |
| } |
| |
| #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE) |
| |
| #include <linux/netfilter/nfnetlink.h> |
| #include <linux/netfilter/nfnetlink_conntrack.h> |
| |
| static int ipv4_tuple_to_nlattr(struct sk_buff *skb, |
| const struct nf_conntrack_tuple *tuple) |
| { |
| if (nla_put_be32(skb, CTA_IP_V4_SRC, tuple->src.u3.ip) || |
| nla_put_be32(skb, CTA_IP_V4_DST, tuple->dst.u3.ip)) |
| goto nla_put_failure; |
| return 0; |
| |
| nla_put_failure: |
| return -1; |
| } |
| |
| static const struct nla_policy ipv4_nla_policy[CTA_IP_MAX+1] = { |
| [CTA_IP_V4_SRC] = { .type = NLA_U32 }, |
| [CTA_IP_V4_DST] = { .type = NLA_U32 }, |
| }; |
| |
| static int ipv4_nlattr_to_tuple(struct nlattr *tb[], |
| struct nf_conntrack_tuple *t) |
| { |
| if (!tb[CTA_IP_V4_SRC] || !tb[CTA_IP_V4_DST]) |
| return -EINVAL; |
| |
| t->src.u3.ip = nla_get_be32(tb[CTA_IP_V4_SRC]); |
| t->dst.u3.ip = nla_get_be32(tb[CTA_IP_V4_DST]); |
| |
| return 0; |
| } |
| |
| static int ipv4_nlattr_tuple_size(void) |
| { |
| return nla_policy_len(ipv4_nla_policy, CTA_IP_MAX + 1); |
| } |
| #endif |
| |
| static struct nf_sockopt_ops so_getorigdst = { |
| .pf = PF_INET, |
| .get_optmin = SO_ORIGINAL_DST, |
| .get_optmax = SO_ORIGINAL_DST+1, |
| .get = &getorigdst, |
| .owner = THIS_MODULE, |
| }; |
| |
| static int ipv4_init_net(struct net *net) |
| { |
| #if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT) |
| struct nf_ip_net *in = &net->ct.nf_ct_proto; |
| in->ctl_table = kmemdup(ip_ct_sysctl_table, |
| sizeof(ip_ct_sysctl_table), |
| GFP_KERNEL); |
| if (!in->ctl_table) |
| return -ENOMEM; |
| |
| in->ctl_table[0].data = &nf_conntrack_max; |
| in->ctl_table[1].data = &net->ct.count; |
| in->ctl_table[2].data = &net->ct.htable_size; |
| in->ctl_table[3].data = &net->ct.sysctl_checksum; |
| in->ctl_table[4].data = &net->ct.sysctl_log_invalid; |
| #endif |
| return 0; |
| } |
| |
| struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv4 __read_mostly = { |
| .l3proto = PF_INET, |
| .name = "ipv4", |
| .pkt_to_tuple = ipv4_pkt_to_tuple, |
| .invert_tuple = ipv4_invert_tuple, |
| .print_tuple = ipv4_print_tuple, |
| .get_l4proto = ipv4_get_l4proto, |
| #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE) |
| .tuple_to_nlattr = ipv4_tuple_to_nlattr, |
| .nlattr_tuple_size = ipv4_nlattr_tuple_size, |
| .nlattr_to_tuple = ipv4_nlattr_to_tuple, |
| .nla_policy = ipv4_nla_policy, |
| #endif |
| #if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT) |
| .ctl_table_path = "net/ipv4/netfilter", |
| #endif |
| .init_net = ipv4_init_net, |
| .me = THIS_MODULE, |
| }; |
| |
| module_param_call(hashsize, nf_conntrack_set_hashsize, param_get_uint, |
| &nf_conntrack_htable_size, 0600); |
| |
| MODULE_ALIAS("nf_conntrack-" __stringify(AF_INET)); |
| MODULE_ALIAS("ip_conntrack"); |
| MODULE_LICENSE("GPL"); |
| |
| static int ipv4_net_init(struct net *net) |
| { |
| int ret = 0; |
| |
| ret = nf_ct_l4proto_pernet_register(net, &nf_conntrack_l4proto_tcp4); |
| if (ret < 0) { |
| pr_err("nf_conntrack_tcp4: pernet registration failed\n"); |
| goto out_tcp; |
| } |
| ret = nf_ct_l4proto_pernet_register(net, &nf_conntrack_l4proto_udp4); |
| if (ret < 0) { |
| pr_err("nf_conntrack_udp4: pernet registration failed\n"); |
| goto out_udp; |
| } |
| ret = nf_ct_l4proto_pernet_register(net, &nf_conntrack_l4proto_icmp); |
| if (ret < 0) { |
| pr_err("nf_conntrack_icmp4: pernet registration failed\n"); |
| goto out_icmp; |
| } |
| ret = nf_ct_l3proto_pernet_register(net, &nf_conntrack_l3proto_ipv4); |
| if (ret < 0) { |
| pr_err("nf_conntrack_ipv4: pernet registration failed\n"); |
| goto out_ipv4; |
| } |
| return 0; |
| out_ipv4: |
| nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_icmp); |
| out_icmp: |
| nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_udp4); |
| out_udp: |
| nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_tcp4); |
| out_tcp: |
| return ret; |
| } |
| |
| static void ipv4_net_exit(struct net *net) |
| { |
| nf_ct_l3proto_pernet_unregister(net, &nf_conntrack_l3proto_ipv4); |
| nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_icmp); |
| nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_udp4); |
| nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_tcp4); |
| } |
| |
| static struct pernet_operations ipv4_net_ops = { |
| .init = ipv4_net_init, |
| .exit = ipv4_net_exit, |
| }; |
| |
| static int __init nf_conntrack_l3proto_ipv4_init(void) |
| { |
| int ret = 0; |
| |
| need_conntrack(); |
| nf_defrag_ipv4_enable(); |
| |
| ret = nf_register_sockopt(&so_getorigdst); |
| if (ret < 0) { |
| printk(KERN_ERR "Unable to register netfilter socket option\n"); |
| return ret; |
| } |
| |
| ret = register_pernet_subsys(&ipv4_net_ops); |
| if (ret < 0) { |
| pr_err("nf_conntrack_ipv4: can't register pernet ops\n"); |
| goto cleanup_sockopt; |
| } |
| |
| ret = nf_register_hooks(ipv4_conntrack_ops, |
| ARRAY_SIZE(ipv4_conntrack_ops)); |
| if (ret < 0) { |
| pr_err("nf_conntrack_ipv4: can't register hooks.\n"); |
| goto cleanup_pernet; |
| } |
| |
| ret = nf_ct_l4proto_register(&nf_conntrack_l4proto_tcp4); |
| if (ret < 0) { |
| pr_err("nf_conntrack_ipv4: can't register tcp4 proto.\n"); |
| goto cleanup_hooks; |
| } |
| |
| ret = nf_ct_l4proto_register(&nf_conntrack_l4proto_udp4); |
| if (ret < 0) { |
| pr_err("nf_conntrack_ipv4: can't register udp4 proto.\n"); |
| goto cleanup_tcp4; |
| } |
| |
| ret = nf_ct_l4proto_register(&nf_conntrack_l4proto_icmp); |
| if (ret < 0) { |
| pr_err("nf_conntrack_ipv4: can't register icmpv4 proto.\n"); |
| goto cleanup_udp4; |
| } |
| |
| ret = nf_ct_l3proto_register(&nf_conntrack_l3proto_ipv4); |
| if (ret < 0) { |
| pr_err("nf_conntrack_ipv4: can't register ipv4 proto.\n"); |
| goto cleanup_icmpv4; |
| } |
| |
| #if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT) |
| ret = nf_conntrack_ipv4_compat_init(); |
| if (ret < 0) |
| goto cleanup_proto; |
| #endif |
| return ret; |
| #if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT) |
| cleanup_proto: |
| nf_ct_l3proto_unregister(&nf_conntrack_l3proto_ipv4); |
| #endif |
| cleanup_icmpv4: |
| nf_ct_l4proto_unregister(&nf_conntrack_l4proto_icmp); |
| cleanup_udp4: |
| nf_ct_l4proto_unregister(&nf_conntrack_l4proto_udp4); |
| cleanup_tcp4: |
| nf_ct_l4proto_unregister(&nf_conntrack_l4proto_tcp4); |
| cleanup_hooks: |
| nf_unregister_hooks(ipv4_conntrack_ops, ARRAY_SIZE(ipv4_conntrack_ops)); |
| cleanup_pernet: |
| unregister_pernet_subsys(&ipv4_net_ops); |
| cleanup_sockopt: |
| nf_unregister_sockopt(&so_getorigdst); |
| return ret; |
| } |
| |
| static void __exit nf_conntrack_l3proto_ipv4_fini(void) |
| { |
| synchronize_net(); |
| #if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT) |
| nf_conntrack_ipv4_compat_fini(); |
| #endif |
| nf_ct_l3proto_unregister(&nf_conntrack_l3proto_ipv4); |
| nf_ct_l4proto_unregister(&nf_conntrack_l4proto_icmp); |
| nf_ct_l4proto_unregister(&nf_conntrack_l4proto_udp4); |
| nf_ct_l4proto_unregister(&nf_conntrack_l4proto_tcp4); |
| nf_unregister_hooks(ipv4_conntrack_ops, ARRAY_SIZE(ipv4_conntrack_ops)); |
| unregister_pernet_subsys(&ipv4_net_ops); |
| nf_unregister_sockopt(&so_getorigdst); |
| } |
| |
| module_init(nf_conntrack_l3proto_ipv4_init); |
| module_exit(nf_conntrack_l3proto_ipv4_fini); |
| |
| void need_ipv4_conntrack(void) |
| { |
| return; |
| } |
| EXPORT_SYMBOL_GPL(need_ipv4_conntrack); |