123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266 |
- /* Kernel module to match connection tracking information.
- * Superset of Rusty's minimalistic state match.
- *
- * (C) 2001 Marc Boucher (marc@mbsi.ca).
- *
- * 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/module.h>
- #include <linux/skbuff.h>
- #if defined(CONFIG_IP_NF_CONNTRACK) || defined(CONFIG_IP_NF_CONNTRACK_MODULE)
- #include <linux/netfilter_ipv4/ip_conntrack.h>
- #include <linux/netfilter_ipv4/ip_conntrack_tuple.h>
- #else
- #include <net/netfilter/nf_conntrack.h>
- #endif
- #include <linux/netfilter/x_tables.h>
- #include <linux/netfilter/xt_conntrack.h>
- #include <net/netfilter/nf_conntrack_compat.h>
- MODULE_LICENSE("GPL");
- MODULE_AUTHOR("Marc Boucher <marc@mbsi.ca>");
- MODULE_DESCRIPTION("iptables connection tracking match module");
- MODULE_ALIAS("ipt_conntrack");
- #if defined(CONFIG_IP_NF_CONNTRACK) || defined(CONFIG_IP_NF_CONNTRACK_MODULE)
- static int
- match(const struct sk_buff *skb,
- const struct net_device *in,
- const struct net_device *out,
- const struct xt_match *match,
- const void *matchinfo,
- int offset,
- unsigned int protoff,
- int *hotdrop)
- {
- const struct xt_conntrack_info *sinfo = matchinfo;
- struct ip_conntrack *ct;
- enum ip_conntrack_info ctinfo;
- unsigned int statebit;
- ct = ip_conntrack_get((struct sk_buff *)skb, &ctinfo);
- #define FWINV(bool, invflg) ((bool) ^ !!(sinfo->invflags & invflg))
- if (ct == &ip_conntrack_untracked)
- statebit = XT_CONNTRACK_STATE_UNTRACKED;
- else if (ct)
- statebit = XT_CONNTRACK_STATE_BIT(ctinfo);
- else
- statebit = XT_CONNTRACK_STATE_INVALID;
- if (sinfo->flags & XT_CONNTRACK_STATE) {
- if (ct) {
- if (test_bit(IPS_SRC_NAT_BIT, &ct->status))
- statebit |= XT_CONNTRACK_STATE_SNAT;
- if (test_bit(IPS_DST_NAT_BIT, &ct->status))
- statebit |= XT_CONNTRACK_STATE_DNAT;
- }
- if (FWINV((statebit & sinfo->statemask) == 0,
- XT_CONNTRACK_STATE))
- return 0;
- }
- if (ct == NULL) {
- if (sinfo->flags & ~XT_CONNTRACK_STATE)
- return 0;
- return 1;
- }
- if (sinfo->flags & XT_CONNTRACK_PROTO &&
- FWINV(ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.protonum !=
- sinfo->tuple[IP_CT_DIR_ORIGINAL].dst.protonum,
- XT_CONNTRACK_PROTO))
- return 0;
- if (sinfo->flags & XT_CONNTRACK_ORIGSRC &&
- FWINV((ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.ip &
- sinfo->sipmsk[IP_CT_DIR_ORIGINAL].s_addr) !=
- sinfo->tuple[IP_CT_DIR_ORIGINAL].src.ip,
- XT_CONNTRACK_ORIGSRC))
- return 0;
- if (sinfo->flags & XT_CONNTRACK_ORIGDST &&
- FWINV((ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.ip &
- sinfo->dipmsk[IP_CT_DIR_ORIGINAL].s_addr) !=
- sinfo->tuple[IP_CT_DIR_ORIGINAL].dst.ip,
- XT_CONNTRACK_ORIGDST))
- return 0;
- if (sinfo->flags & XT_CONNTRACK_REPLSRC &&
- FWINV((ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.ip &
- sinfo->sipmsk[IP_CT_DIR_REPLY].s_addr) !=
- sinfo->tuple[IP_CT_DIR_REPLY].src.ip,
- XT_CONNTRACK_REPLSRC))
- return 0;
- if (sinfo->flags & XT_CONNTRACK_REPLDST &&
- FWINV((ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.ip &
- sinfo->dipmsk[IP_CT_DIR_REPLY].s_addr) !=
- sinfo->tuple[IP_CT_DIR_REPLY].dst.ip,
- XT_CONNTRACK_REPLDST))
- return 0;
- if (sinfo->flags & XT_CONNTRACK_STATUS &&
- FWINV((ct->status & sinfo->statusmask) == 0,
- XT_CONNTRACK_STATUS))
- return 0;
- if (sinfo->flags & XT_CONNTRACK_EXPIRES) {
- unsigned long expires = timer_pending(&ct->timeout) ?
- (ct->timeout.expires - jiffies)/HZ : 0;
- if (FWINV(!(expires >= sinfo->expires_min &&
- expires <= sinfo->expires_max),
- XT_CONNTRACK_EXPIRES))
- return 0;
- }
- return 1;
- }
- #else /* CONFIG_IP_NF_CONNTRACK */
- static int
- match(const struct sk_buff *skb,
- const struct net_device *in,
- const struct net_device *out,
- const struct xt_match *match,
- const void *matchinfo,
- int offset,
- unsigned int protoff,
- int *hotdrop)
- {
- const struct xt_conntrack_info *sinfo = matchinfo;
- struct nf_conn *ct;
- enum ip_conntrack_info ctinfo;
- unsigned int statebit;
- ct = nf_ct_get((struct sk_buff *)skb, &ctinfo);
- #define FWINV(bool,invflg) ((bool) ^ !!(sinfo->invflags & invflg))
- if (ct == &nf_conntrack_untracked)
- statebit = XT_CONNTRACK_STATE_UNTRACKED;
- else if (ct)
- statebit = XT_CONNTRACK_STATE_BIT(ctinfo);
- else
- statebit = XT_CONNTRACK_STATE_INVALID;
- if (sinfo->flags & XT_CONNTRACK_STATE) {
- if (ct) {
- if (test_bit(IPS_SRC_NAT_BIT, &ct->status))
- statebit |= XT_CONNTRACK_STATE_SNAT;
- if (test_bit(IPS_DST_NAT_BIT, &ct->status))
- statebit |= XT_CONNTRACK_STATE_DNAT;
- }
- if (FWINV((statebit & sinfo->statemask) == 0,
- XT_CONNTRACK_STATE))
- return 0;
- }
- if (ct == NULL) {
- if (sinfo->flags & ~XT_CONNTRACK_STATE)
- return 0;
- return 1;
- }
- if (sinfo->flags & XT_CONNTRACK_PROTO &&
- FWINV(ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.protonum !=
- sinfo->tuple[IP_CT_DIR_ORIGINAL].dst.protonum,
- XT_CONNTRACK_PROTO))
- return 0;
- if (sinfo->flags & XT_CONNTRACK_ORIGSRC &&
- FWINV((ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.ip &
- sinfo->sipmsk[IP_CT_DIR_ORIGINAL].s_addr) !=
- sinfo->tuple[IP_CT_DIR_ORIGINAL].src.ip,
- XT_CONNTRACK_ORIGSRC))
- return 0;
- if (sinfo->flags & XT_CONNTRACK_ORIGDST &&
- FWINV((ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u3.ip &
- sinfo->dipmsk[IP_CT_DIR_ORIGINAL].s_addr) !=
- sinfo->tuple[IP_CT_DIR_ORIGINAL].dst.ip,
- XT_CONNTRACK_ORIGDST))
- return 0;
- if (sinfo->flags & XT_CONNTRACK_REPLSRC &&
- FWINV((ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.u3.ip &
- sinfo->sipmsk[IP_CT_DIR_REPLY].s_addr) !=
- sinfo->tuple[IP_CT_DIR_REPLY].src.ip,
- XT_CONNTRACK_REPLSRC))
- return 0;
- if (sinfo->flags & XT_CONNTRACK_REPLDST &&
- FWINV((ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u3.ip &
- sinfo->dipmsk[IP_CT_DIR_REPLY].s_addr) !=
- sinfo->tuple[IP_CT_DIR_REPLY].dst.ip,
- XT_CONNTRACK_REPLDST))
- return 0;
- if (sinfo->flags & XT_CONNTRACK_STATUS &&
- FWINV((ct->status & sinfo->statusmask) == 0,
- XT_CONNTRACK_STATUS))
- return 0;
- if(sinfo->flags & XT_CONNTRACK_EXPIRES) {
- unsigned long expires = timer_pending(&ct->timeout) ?
- (ct->timeout.expires - jiffies)/HZ : 0;
- if (FWINV(!(expires >= sinfo->expires_min &&
- expires <= sinfo->expires_max),
- XT_CONNTRACK_EXPIRES))
- return 0;
- }
- return 1;
- }
- #endif /* CONFIG_NF_IP_CONNTRACK */
- static int
- checkentry(const char *tablename,
- const void *ip,
- const struct xt_match *match,
- void *matchinfo,
- unsigned int hook_mask)
- {
- if (nf_ct_l3proto_try_module_get(match->family) < 0) {
- printk(KERN_WARNING "can't load conntrack support for "
- "proto=%d\n", match->family);
- return 0;
- }
- return 1;
- }
- static void destroy(const struct xt_match *match, void *matchinfo)
- {
- nf_ct_l3proto_module_put(match->family);
- }
- static struct xt_match conntrack_match = {
- .name = "conntrack",
- .match = match,
- .checkentry = checkentry,
- .destroy = destroy,
- .matchsize = sizeof(struct xt_conntrack_info),
- .family = AF_INET,
- .me = THIS_MODULE,
- };
- static int __init xt_conntrack_init(void)
- {
- return xt_register_match(&conntrack_match);
- }
- static void __exit xt_conntrack_fini(void)
- {
- xt_unregister_match(&conntrack_match);
- }
- module_init(xt_conntrack_init);
- module_exit(xt_conntrack_fini);
|