| /* (C) 1999-2001 Paul `Rusty' Russell |
| * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org> |
| * |
| * 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. |
| * |
| * 16 Dec 2003: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp> |
| * - move L3 protocol dependent part to this file. |
| * 23 Mar 2004: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp> |
| * - add get_features() to support various size of conntrack |
| * structures. |
| * |
| * Derived from net/ipv4/netfilter/ip_conntrack_standalone.c |
| */ |
| |
| #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_core.h> |
| #include <net/netfilter/ipv4/nf_conntrack_ipv4.h> |
| |
| #if 0 |
| #define DEBUGP printk |
| #else |
| #define DEBUGP(format, args...) |
| #endif |
| |
| static int ipv4_pkt_to_tuple(const struct sk_buff *skb, unsigned int nhoff, |
| struct nf_conntrack_tuple *tuple) |
| { |
| __be32 _addrs[2], *ap; |
| ap = skb_header_pointer(skb, nhoff + offsetof(struct iphdr, saddr), |
| sizeof(u_int32_t) * 2, _addrs); |
| if (ap == NULL) |
| return 0; |
| |
| tuple->src.u3.ip = ap[0]; |
| tuple->dst.u3.ip = ap[1]; |
| |
| return 1; |
| } |
| |
| static int 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 1; |
| } |
| |
| static int ipv4_print_tuple(struct seq_file *s, |
| const struct nf_conntrack_tuple *tuple) |
| { |
| return seq_printf(s, "src=%u.%u.%u.%u dst=%u.%u.%u.%u ", |
| NIPQUAD(tuple->src.u3.ip), |
| NIPQUAD(tuple->dst.u3.ip)); |
| } |
| |
| static int ipv4_print_conntrack(struct seq_file *s, |
| const struct nf_conn *conntrack) |
| { |
| return 0; |
| } |
| |
| /* Returns new sk_buff, or NULL */ |
| static struct sk_buff * |
| nf_ct_ipv4_gather_frags(struct sk_buff *skb, u_int32_t user) |
| { |
| skb_orphan(skb); |
| |
| local_bh_disable(); |
| skb = ip_defrag(skb, user); |
| local_bh_enable(); |
| |
| if (skb) |
| ip_send_check(skb->nh.iph); |
| |
| return skb; |
| } |
| |
| static int |
| ipv4_prepare(struct sk_buff **pskb, unsigned int hooknum, unsigned int *dataoff, |
| u_int8_t *protonum) |
| { |
| /* Never happen */ |
| if ((*pskb)->nh.iph->frag_off & htons(IP_OFFSET)) { |
| if (net_ratelimit()) { |
| printk(KERN_ERR "ipv4_prepare: Frag of proto %u (hook=%u)\n", |
| (*pskb)->nh.iph->protocol, hooknum); |
| } |
| return -NF_DROP; |
| } |
| |
| *dataoff = (*pskb)->nh.raw - (*pskb)->data + (*pskb)->nh.iph->ihl*4; |
| *protonum = (*pskb)->nh.iph->protocol; |
| |
| return NF_ACCEPT; |
| } |
| |
| int nf_nat_module_is_loaded = 0; |
| static u_int32_t ipv4_get_features(const struct nf_conntrack_tuple *tuple) |
| { |
| if (nf_nat_module_is_loaded) |
| return NF_CT_F_NAT; |
| |
| return NF_CT_F_BASIC; |
| } |
| |
| static unsigned int ipv4_confirm(unsigned int hooknum, |
| struct sk_buff **pskb, |
| const struct net_device *in, |
| const struct net_device *out, |
| int (*okfn)(struct sk_buff *)) |
| { |
| /* We've seen it coming out the other side: confirm it */ |
| return nf_conntrack_confirm(pskb); |
| } |
| |
| static unsigned int ipv4_conntrack_help(unsigned int hooknum, |
| struct sk_buff **pskb, |
| const struct net_device *in, |
| const struct net_device *out, |
| int (*okfn)(struct sk_buff *)) |
| { |
| struct nf_conn *ct; |
| enum ip_conntrack_info ctinfo; |
| struct nf_conn_help *help; |
| |
| /* This is where we call the helper: as the packet goes out. */ |
| ct = nf_ct_get(*pskb, &ctinfo); |
| if (!ct || ctinfo == IP_CT_RELATED + IP_CT_IS_REPLY) |
| return NF_ACCEPT; |
| |
| help = nfct_help(ct); |
| if (!help || !help->helper) |
| return NF_ACCEPT; |
| |
| return help->helper->help(pskb, |
| (*pskb)->nh.raw - (*pskb)->data |
| + (*pskb)->nh.iph->ihl*4, |
| ct, ctinfo); |
| } |
| |
| static unsigned int ipv4_conntrack_defrag(unsigned int hooknum, |
| struct sk_buff **pskb, |
| const struct net_device *in, |
| const struct net_device *out, |
| int (*okfn)(struct sk_buff *)) |
| { |
| #if !defined(CONFIG_IP_NF_NAT) && !defined(CONFIG_IP_NF_NAT_MODULE) |
| /* Previously seen (loopback)? Ignore. Do this before |
| fragment check. */ |
| if ((*pskb)->nfct) |
| return NF_ACCEPT; |
| #endif |
| |
| /* Gather fragments. */ |
| if ((*pskb)->nh.iph->frag_off & htons(IP_MF|IP_OFFSET)) { |
| *pskb = nf_ct_ipv4_gather_frags(*pskb, |
| hooknum == NF_IP_PRE_ROUTING ? |
| IP_DEFRAG_CONNTRACK_IN : |
| IP_DEFRAG_CONNTRACK_OUT); |
| if (!*pskb) |
| return NF_STOLEN; |
| } |
| return NF_ACCEPT; |
| } |
| |
| static unsigned int ipv4_conntrack_in(unsigned int hooknum, |
| struct sk_buff **pskb, |
| const struct net_device *in, |
| const struct net_device *out, |
| int (*okfn)(struct sk_buff *)) |
| { |
| return nf_conntrack_in(PF_INET, hooknum, pskb); |
| } |
| |
| static unsigned int ipv4_conntrack_local(unsigned int hooknum, |
| struct sk_buff **pskb, |
| const struct net_device *in, |
| const struct net_device *out, |
| int (*okfn)(struct sk_buff *)) |
| { |
| /* root is playing with raw sockets. */ |
| if ((*pskb)->len < sizeof(struct iphdr) |
| || (*pskb)->nh.iph->ihl * 4 < sizeof(struct iphdr)) { |
| if (net_ratelimit()) |
| printk("ipt_hook: happy cracking.\n"); |
| return NF_ACCEPT; |
| } |
| return nf_conntrack_in(PF_INET, hooknum, pskb); |
| } |
| |
| /* Connection tracking may drop packets, but never alters them, so |
| make it the first hook. */ |
| static struct nf_hook_ops ipv4_conntrack_ops[] = { |
| { |
| .hook = ipv4_conntrack_defrag, |
| .owner = THIS_MODULE, |
| .pf = PF_INET, |
| .hooknum = NF_IP_PRE_ROUTING, |
| .priority = NF_IP_PRI_CONNTRACK_DEFRAG, |
| }, |
| { |
| .hook = ipv4_conntrack_in, |
| .owner = THIS_MODULE, |
| .pf = PF_INET, |
| .hooknum = NF_IP_PRE_ROUTING, |
| .priority = NF_IP_PRI_CONNTRACK, |
| }, |
| { |
| .hook = ipv4_conntrack_defrag, |
| .owner = THIS_MODULE, |
| .pf = PF_INET, |
| .hooknum = NF_IP_LOCAL_OUT, |
| .priority = NF_IP_PRI_CONNTRACK_DEFRAG, |
| }, |
| { |
| .hook = ipv4_conntrack_local, |
| .owner = THIS_MODULE, |
| .pf = PF_INET, |
| .hooknum = NF_IP_LOCAL_OUT, |
| .priority = NF_IP_PRI_CONNTRACK, |
| }, |
| { |
| .hook = ipv4_conntrack_help, |
| .owner = THIS_MODULE, |
| .pf = PF_INET, |
| .hooknum = NF_IP_POST_ROUTING, |
| .priority = NF_IP_PRI_CONNTRACK_HELPER, |
| }, |
| { |
| .hook = ipv4_conntrack_help, |
| .owner = THIS_MODULE, |
| .pf = PF_INET, |
| .hooknum = NF_IP_LOCAL_IN, |
| .priority = NF_IP_PRI_CONNTRACK_HELPER, |
| }, |
| { |
| .hook = ipv4_confirm, |
| .owner = THIS_MODULE, |
| .pf = PF_INET, |
| .hooknum = NF_IP_POST_ROUTING, |
| .priority = NF_IP_PRI_CONNTRACK_CONFIRM, |
| }, |
| { |
| .hook = ipv4_confirm, |
| .owner = THIS_MODULE, |
| .pf = PF_INET, |
| .hooknum = NF_IP_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[] = { |
| { |
| .ctl_name = NET_IPV4_NF_CONNTRACK_MAX, |
| .procname = "ip_conntrack_max", |
| .data = &nf_conntrack_max, |
| .maxlen = sizeof(int), |
| .mode = 0644, |
| .proc_handler = &proc_dointvec, |
| }, |
| { |
| .ctl_name = NET_IPV4_NF_CONNTRACK_COUNT, |
| .procname = "ip_conntrack_count", |
| .data = &nf_conntrack_count, |
| .maxlen = sizeof(int), |
| .mode = 0444, |
| .proc_handler = &proc_dointvec, |
| }, |
| { |
| .ctl_name = NET_IPV4_NF_CONNTRACK_BUCKETS, |
| .procname = "ip_conntrack_buckets", |
| .data = &nf_conntrack_htable_size, |
| .maxlen = sizeof(unsigned int), |
| .mode = 0444, |
| .proc_handler = &proc_dointvec, |
| }, |
| { |
| .ctl_name = NET_IPV4_NF_CONNTRACK_CHECKSUM, |
| .procname = "ip_conntrack_checksum", |
| .data = &nf_conntrack_checksum, |
| .maxlen = sizeof(int), |
| .mode = 0644, |
| .proc_handler = &proc_dointvec, |
| }, |
| { |
| .ctl_name = NET_IPV4_NF_CONNTRACK_LOG_INVALID, |
| .procname = "ip_conntrack_log_invalid", |
| .data = &nf_ct_log_invalid, |
| .maxlen = sizeof(unsigned int), |
| .mode = 0644, |
| .proc_handler = &proc_dointvec_minmax, |
| .strategy = &sysctl_intvec, |
| .extra1 = &log_invalid_proto_min, |
| .extra2 = &log_invalid_proto_max, |
| }, |
| { |
| .ctl_name = 0 |
| } |
| }; |
| #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) |
| { |
| struct inet_sock *inet = inet_sk(sk); |
| struct nf_conntrack_tuple_hash *h; |
| struct nf_conntrack_tuple tuple; |
| |
| NF_CT_TUPLE_U_BLANK(&tuple); |
| tuple.src.u3.ip = inet->rcv_saddr; |
| tuple.src.u.tcp.port = inet->sport; |
| tuple.dst.u3.ip = inet->daddr; |
| tuple.dst.u.tcp.port = inet->dport; |
| tuple.src.l3num = PF_INET; |
| tuple.dst.protonum = IPPROTO_TCP; |
| |
| /* We only do TCP at the moment: is there a better way? */ |
| if (strcmp(sk->sk_prot->name, "TCP")) { |
| DEBUGP("SO_ORIGINAL_DST: Not a TCP socket\n"); |
| return -ENOPROTOOPT; |
| } |
| |
| if ((unsigned int) *len < sizeof(struct sockaddr_in)) { |
| DEBUGP("SO_ORIGINAL_DST: len %u not %u\n", |
| *len, sizeof(struct sockaddr_in)); |
| return -EINVAL; |
| } |
| |
| h = nf_conntrack_find_get(&tuple, NULL); |
| 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)); |
| |
| DEBUGP("SO_ORIGINAL_DST: %u.%u.%u.%u %u\n", |
| NIPQUAD(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; |
| } |
| DEBUGP("SO_ORIGINAL_DST: Can't find %u.%u.%u.%u/%u-%u.%u.%u.%u/%u.\n", |
| NIPQUAD(tuple.src.u3.ip), ntohs(tuple.src.u.tcp.port), |
| NIPQUAD(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_nfattr(struct sk_buff *skb, |
| const struct nf_conntrack_tuple *tuple) |
| { |
| NFA_PUT(skb, CTA_IP_V4_SRC, sizeof(u_int32_t), |
| &tuple->src.u3.ip); |
| NFA_PUT(skb, CTA_IP_V4_DST, sizeof(u_int32_t), |
| &tuple->dst.u3.ip); |
| return 0; |
| |
| nfattr_failure: |
| return -1; |
| } |
| |
| static const size_t cta_min_ip[CTA_IP_MAX] = { |
| [CTA_IP_V4_SRC-1] = sizeof(u_int32_t), |
| [CTA_IP_V4_DST-1] = sizeof(u_int32_t), |
| }; |
| |
| static int ipv4_nfattr_to_tuple(struct nfattr *tb[], |
| struct nf_conntrack_tuple *t) |
| { |
| if (!tb[CTA_IP_V4_SRC-1] || !tb[CTA_IP_V4_DST-1]) |
| return -EINVAL; |
| |
| if (nfattr_bad_size(tb, CTA_IP_MAX, cta_min_ip)) |
| return -EINVAL; |
| |
| t->src.u3.ip = *(__be32 *)NFA_DATA(tb[CTA_IP_V4_SRC-1]); |
| t->dst.u3.ip = *(__be32 *)NFA_DATA(tb[CTA_IP_V4_DST-1]); |
| |
| return 0; |
| } |
| #endif |
| |
| static struct nf_sockopt_ops so_getorigdst = { |
| .pf = PF_INET, |
| .get_optmin = SO_ORIGINAL_DST, |
| .get_optmax = SO_ORIGINAL_DST+1, |
| .get = &getorigdst, |
| }; |
| |
| struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv4 = { |
| .l3proto = PF_INET, |
| .name = "ipv4", |
| .pkt_to_tuple = ipv4_pkt_to_tuple, |
| .invert_tuple = ipv4_invert_tuple, |
| .print_tuple = ipv4_print_tuple, |
| .print_conntrack = ipv4_print_conntrack, |
| .prepare = ipv4_prepare, |
| .get_features = ipv4_get_features, |
| #if defined(CONFIG_NF_CT_NETLINK) || \ |
| defined(CONFIG_NF_CT_NETLINK_MODULE) |
| .tuple_to_nfattr = ipv4_tuple_to_nfattr, |
| .nfattr_to_tuple = ipv4_nfattr_to_tuple, |
| #endif |
| #if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT) |
| .ctl_table_path = nf_net_ipv4_netfilter_sysctl_path, |
| .ctl_table = ip_ct_sysctl_table, |
| #endif |
| .me = THIS_MODULE, |
| }; |
| |
| MODULE_ALIAS("nf_conntrack-" __stringify(AF_INET)); |
| MODULE_ALIAS("ip_conntrack"); |
| MODULE_LICENSE("GPL"); |
| |
| static int __init nf_conntrack_l3proto_ipv4_init(void) |
| { |
| int ret = 0; |
| |
| need_conntrack(); |
| |
| ret = nf_register_sockopt(&so_getorigdst); |
| if (ret < 0) { |
| printk(KERN_ERR "Unable to register netfilter socket option\n"); |
| return ret; |
| } |
| |
| ret = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_tcp4); |
| if (ret < 0) { |
| printk("nf_conntrack_ipv4: can't register tcp.\n"); |
| goto cleanup_sockopt; |
| } |
| |
| ret = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_udp4); |
| if (ret < 0) { |
| printk("nf_conntrack_ipv4: can't register udp.\n"); |
| goto cleanup_tcp; |
| } |
| |
| ret = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_icmp); |
| if (ret < 0) { |
| printk("nf_conntrack_ipv4: can't register icmp.\n"); |
| goto cleanup_udp; |
| } |
| |
| ret = nf_conntrack_l3proto_register(&nf_conntrack_l3proto_ipv4); |
| if (ret < 0) { |
| printk("nf_conntrack_ipv4: can't register ipv4\n"); |
| goto cleanup_icmp; |
| } |
| |
| ret = nf_register_hooks(ipv4_conntrack_ops, |
| ARRAY_SIZE(ipv4_conntrack_ops)); |
| if (ret < 0) { |
| printk("nf_conntrack_ipv4: can't register hooks.\n"); |
| goto cleanup_ipv4; |
| } |
| #if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT) |
| ret = nf_conntrack_ipv4_compat_init(); |
| if (ret < 0) |
| goto cleanup_hooks; |
| #endif |
| return ret; |
| #if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT) |
| cleanup_hooks: |
| nf_unregister_hooks(ipv4_conntrack_ops, ARRAY_SIZE(ipv4_conntrack_ops)); |
| #endif |
| cleanup_ipv4: |
| nf_conntrack_l3proto_unregister(&nf_conntrack_l3proto_ipv4); |
| cleanup_icmp: |
| nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_icmp); |
| cleanup_udp: |
| nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udp4); |
| cleanup_tcp: |
| nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_tcp4); |
| 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_unregister_hooks(ipv4_conntrack_ops, ARRAY_SIZE(ipv4_conntrack_ops)); |
| nf_conntrack_l3proto_unregister(&nf_conntrack_l3proto_ipv4); |
| nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_icmp); |
| nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udp4); |
| nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_tcp4); |
| nf_unregister_sockopt(&so_getorigdst); |
| } |
| |
| module_init(nf_conntrack_l3proto_ipv4_init); |
| module_exit(nf_conntrack_l3proto_ipv4_fini); |
| |
| EXPORT_SYMBOL(nf_ct_ipv4_gather_frags); |
| #ifdef CONFIG_NF_NAT_NEEDED |
| EXPORT_SYMBOL(nf_nat_module_is_loaded); |
| #endif |