| /* 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> |
| |
| 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(ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.ip != |
| ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.ip) |
| statebit |= XT_CONNTRACK_STATE_SNAT; |
| |
| if(ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.ip != |
| ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.ip) |
| statebit |= XT_CONNTRACK_STATE_DNAT; |
| } |
| |
| if (FWINV((statebit & sinfo->statemask) == 0, XT_CONNTRACK_STATE)) |
| return 0; |
| } |
| |
| if(sinfo->flags & XT_CONNTRACK_PROTO) { |
| if (!ct || 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) { |
| if (!ct || 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) { |
| if (!ct || 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) { |
| if (!ct || 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) { |
| if (!ct || 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) { |
| if (!ct || FWINV((ct->status & sinfo->statusmask) == 0, XT_CONNTRACK_STATUS)) |
| return 0; |
| } |
| |
| if(sinfo->flags & XT_CONNTRACK_EXPIRES) { |
| unsigned long expires; |
| |
| if(!ct) |
| return 0; |
| |
| 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(ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.ip != |
| ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u3.ip) |
| statebit |= XT_CONNTRACK_STATE_SNAT; |
| |
| if(ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u3.ip != |
| ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.u3.ip) |
| statebit |= XT_CONNTRACK_STATE_DNAT; |
| } |
| |
| if (FWINV((statebit & sinfo->statemask) == 0, XT_CONNTRACK_STATE)) |
| return 0; |
| } |
| |
| if(sinfo->flags & XT_CONNTRACK_PROTO) { |
| if (!ct || 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) { |
| if (!ct || 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) { |
| if (!ct || 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) { |
| if (!ct || 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) { |
| if (!ct || 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) { |
| if (!ct || FWINV((ct->status & sinfo->statusmask) == 0, XT_CONNTRACK_STATUS)) |
| return 0; |
| } |
| |
| if(sinfo->flags & XT_CONNTRACK_EXPIRES) { |
| unsigned long expires; |
| |
| if(!ct) |
| return 0; |
| |
| 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 struct xt_match conntrack_match = { |
| .name = "conntrack", |
| .match = match, |
| .matchsize = sizeof(struct xt_conntrack_info), |
| .me = THIS_MODULE, |
| }; |
| |
| static int __init init(void) |
| { |
| int ret; |
| need_conntrack(); |
| ret = xt_register_match(AF_INET, &conntrack_match); |
| |
| return ret; |
| } |
| |
| static void __exit fini(void) |
| { |
| xt_unregister_match(AF_INET, &conntrack_match); |
| } |
| |
| module_init(init); |
| module_exit(fini); |