diff options
Diffstat (limited to 'net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c')
| -rw-r--r-- | net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c | 571 |
1 files changed, 571 insertions, 0 deletions
diff --git a/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c b/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c new file mode 100644 index 00000000000000..8202c1c0afadae --- /dev/null +++ b/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c @@ -0,0 +1,571 @@ +/* (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/config.h> +#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/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_protocol.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 + +DECLARE_PER_CPU(struct nf_conntrack_stat, nf_conntrack_stat); + +static int ipv4_pkt_to_tuple(const struct sk_buff *skb, unsigned int nhoff, + struct nf_conntrack_tuple *tuple) +{ + u_int32_t _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 nat_module_is_loaded = 0; +static u_int32_t ipv4_get_features(const struct nf_conntrack_tuple *tuple) +{ + if (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; + + /* This is where we call the helper: as the packet goes out. */ + ct = nf_ct_get(*pskb, &ctinfo); + if (ct && ct->helper) { + unsigned int ret; + ret = ct->helper->help(pskb, + (*pskb)->nh.raw - (*pskb)->data + + (*pskb)->nh.iph->ihl*4, + ct, ctinfo); + if (ret != NF_ACCEPT) + return ret; + } + return NF_ACCEPT; +} + +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_refrag(unsigned int hooknum, + struct sk_buff **pskb, + const struct net_device *in, + const struct net_device *out, + int (*okfn)(struct sk_buff *)) +{ + struct rtable *rt = (struct rtable *)(*pskb)->dst; + + /* We've seen it coming out the other side: confirm */ + if (ipv4_confirm(hooknum, pskb, in, out, okfn) != NF_ACCEPT) + return NF_DROP; + + /* Local packets are never produced too large for their + interface. We degfragment them at LOCAL_OUT, however, + so we have to refragment them here. */ + if ((*pskb)->len > dst_mtu(&rt->u.dst) && + !skb_shinfo(*pskb)->tso_size) { + /* No hook can be after us, so this should be OK. */ + ip_fragment(*pskb, okfn); + 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_defrag_ops = { + .hook = ipv4_conntrack_defrag, + .owner = THIS_MODULE, + .pf = PF_INET, + .hooknum = NF_IP_PRE_ROUTING, + .priority = NF_IP_PRI_CONNTRACK_DEFRAG, +}; + +static struct nf_hook_ops ipv4_conntrack_in_ops = { + .hook = ipv4_conntrack_in, + .owner = THIS_MODULE, + .pf = PF_INET, + .hooknum = NF_IP_PRE_ROUTING, + .priority = NF_IP_PRI_CONNTRACK, +}; + +static struct nf_hook_ops ipv4_conntrack_defrag_local_out_ops = { + .hook = ipv4_conntrack_defrag, + .owner = THIS_MODULE, + .pf = PF_INET, + .hooknum = NF_IP_LOCAL_OUT, + .priority = NF_IP_PRI_CONNTRACK_DEFRAG, +}; + +static struct nf_hook_ops ipv4_conntrack_local_out_ops = { + .hook = ipv4_conntrack_local, + .owner = THIS_MODULE, + .pf = PF_INET, + .hooknum = NF_IP_LOCAL_OUT, + .priority = NF_IP_PRI_CONNTRACK, +}; + +/* helpers */ +static struct nf_hook_ops ipv4_conntrack_helper_out_ops = { + .hook = ipv4_conntrack_help, + .owner = THIS_MODULE, + .pf = PF_INET, + .hooknum = NF_IP_POST_ROUTING, + .priority = NF_IP_PRI_CONNTRACK_HELPER, +}; + +static struct nf_hook_ops ipv4_conntrack_helper_in_ops = { + .hook = ipv4_conntrack_help, + .owner = THIS_MODULE, + .pf = PF_INET, + .hooknum = NF_IP_LOCAL_IN, + .priority = NF_IP_PRI_CONNTRACK_HELPER, +}; + + +/* Refragmenter; last chance. */ +static struct nf_hook_ops ipv4_conntrack_out_ops = { + .hook = ipv4_refrag, + .owner = THIS_MODULE, + .pf = PF_INET, + .hooknum = NF_IP_POST_ROUTING, + .priority = NF_IP_PRI_CONNTRACK_CONFIRM, +}; + +static struct nf_hook_ops ipv4_conntrack_local_in_ops = { + .hook = ipv4_confirm, + .owner = THIS_MODULE, + .pf = PF_INET, + .hooknum = NF_IP_LOCAL_IN, + .priority = NF_IP_PRI_CONNTRACK_CONFIRM, +}; + +#ifdef CONFIG_SYSCTL +/* From nf_conntrack_proto_icmp.c */ +extern unsigned long nf_ct_icmp_timeout; +static struct ctl_table_header *nf_ct_ipv4_sysctl_header; + +static ctl_table nf_ct_sysctl_table[] = { + { + .ctl_name = NET_NF_CONNTRACK_ICMP_TIMEOUT, + .procname = "nf_conntrack_icmp_timeout", + .data = &nf_ct_icmp_timeout, + .maxlen = sizeof(unsigned int), + .mode = 0644, + .proc_handler = &proc_dointvec_jiffies, + }, + { .ctl_name = 0 } +}; + +static ctl_table nf_ct_netfilter_table[] = { + { + .ctl_name = NET_NETFILTER, + .procname = "netfilter", + .mode = 0555, + .child = nf_ct_sysctl_table, + }, + { .ctl_name = 0 } +}; + +static ctl_table nf_ct_net_table[] = { + { + .ctl_name = CTL_NET, + .procname = "net", + .mode = 0555, + .child = nf_ct_netfilter_table, + }, + { .ctl_name = 0 } +}; +#endif + +/* 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; + + 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; +} + +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, + .me = THIS_MODULE, +}; + +extern struct nf_conntrack_protocol nf_conntrack_protocol_tcp4; +extern struct nf_conntrack_protocol nf_conntrack_protocol_udp4; +extern struct nf_conntrack_protocol nf_conntrack_protocol_icmp; +static int init_or_cleanup(int init) +{ + int ret = 0; + + if (!init) goto cleanup; + + ret = nf_register_sockopt(&so_getorigdst); + if (ret < 0) { + printk(KERN_ERR "Unable to register netfilter socket option\n"); + goto cleanup_nothing; + } + + ret = nf_conntrack_protocol_register(&nf_conntrack_protocol_tcp4); + if (ret < 0) { + printk("nf_conntrack_ipv4: can't register tcp.\n"); + goto cleanup_sockopt; + } + + ret = nf_conntrack_protocol_register(&nf_conntrack_protocol_udp4); + if (ret < 0) { + printk("nf_conntrack_ipv4: can't register udp.\n"); + goto cleanup_tcp; + } + + ret = nf_conntrack_protocol_register(&nf_conntrack_protocol_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_hook(&ipv4_conntrack_defrag_ops); + if (ret < 0) { + printk("nf_conntrack_ipv4: can't register pre-routing defrag hook.\n"); + goto cleanup_ipv4; + } + ret = nf_register_hook(&ipv4_conntrack_defrag_local_out_ops); + if (ret < 0) { + printk("nf_conntrack_ipv4: can't register local_out defrag hook.\n"); + goto cleanup_defragops; + } + + ret = nf_register_hook(&ipv4_conntrack_in_ops); + if (ret < 0) { + printk("nf_conntrack_ipv4: can't register pre-routing hook.\n"); + goto cleanup_defraglocalops; + } + + ret = nf_register_hook(&ipv4_conntrack_local_out_ops); + if (ret < 0) { + printk("nf_conntrack_ipv4: can't register local out hook.\n"); + goto cleanup_inops; + } + + ret = nf_register_hook(&ipv4_conntrack_helper_in_ops); + if (ret < 0) { + printk("nf_conntrack_ipv4: can't register local helper hook.\n"); + goto cleanup_inandlocalops; + } + + ret = nf_register_hook(&ipv4_conntrack_helper_out_ops); + if (ret < 0) { + printk("nf_conntrack_ipv4: can't register postrouting helper hook.\n"); + goto cleanup_helperinops; + } + + ret = nf_register_hook(&ipv4_conntrack_out_ops); + if (ret < 0) { + printk("nf_conntrack_ipv4: can't register post-routing hook.\n"); + goto cleanup_helperoutops; + } + + ret = nf_register_hook(&ipv4_conntrack_local_in_ops); + if (ret < 0) { + printk("nf_conntrack_ipv4: can't register local in hook.\n"); + goto cleanup_inoutandlocalops; + } + +#ifdef CONFIG_SYSCTL + nf_ct_ipv4_sysctl_header = register_sysctl_table(nf_ct_net_table, 0); + if (nf_ct_ipv4_sysctl_header == NULL) { + printk("nf_conntrack: can't register to sysctl.\n"); + ret = -ENOMEM; + goto cleanup_localinops; + } +#endif + + /* For use by REJECT target */ + ip_ct_attach = __nf_conntrack_attach; + + return ret; + + cleanup: + synchronize_net(); + ip_ct_attach = NULL; +#ifdef CONFIG_SYSCTL + unregister_sysctl_table(nf_ct_ipv4_sysctl_header); + cleanup_localinops: +#endif + nf_unregister_hook(&ipv4_conntrack_local_in_ops); + cleanup_inoutandlocalops: + nf_unregister_hook(&ipv4_conntrack_out_ops); + cleanup_helperoutops: + nf_unregister_hook(&ipv4_conntrack_helper_out_ops); + cleanup_helperinops: + nf_unregister_hook(&ipv4_conntrack_helper_in_ops); + cleanup_inandlocalops: + nf_unregister_hook(&ipv4_conntrack_local_out_ops); + cleanup_inops: + nf_unregister_hook(&ipv4_conntrack_in_ops); + cleanup_defraglocalops: + nf_unregister_hook(&ipv4_conntrack_defrag_local_out_ops); + cleanup_defragops: + nf_unregister_hook(&ipv4_conntrack_defrag_ops); + cleanup_ipv4: + nf_conntrack_l3proto_unregister(&nf_conntrack_l3proto_ipv4); + cleanup_icmp: + nf_conntrack_protocol_unregister(&nf_conntrack_protocol_icmp); + cleanup_udp: + nf_conntrack_protocol_unregister(&nf_conntrack_protocol_udp4); + cleanup_tcp: + nf_conntrack_protocol_unregister(&nf_conntrack_protocol_tcp4); + cleanup_sockopt: + nf_unregister_sockopt(&so_getorigdst); + cleanup_nothing: + return ret; +} + +MODULE_LICENSE("GPL"); + +static int __init init(void) +{ + need_nf_conntrack(); + return init_or_cleanup(1); +} + +static void __exit fini(void) +{ + init_or_cleanup(0); +} + +module_init(init); +module_exit(fini); + +void need_ip_conntrack(void) +{ +} + +EXPORT_SYMBOL(need_ip_conntrack); +EXPORT_SYMBOL(nf_ct_ipv4_gather_frags); |