From 2e4e6a17af35be359cc8f1c924f8f198fbd478cc Mon Sep 17 00:00:00 2001 From: Harald Welte Date: Thu, 12 Jan 2006 13:30:04 -0800 Subject: [NETFILTER] x_tables: Abstraction layer for {ip,ip6,arp}_tables This monster-patch tries to do the best job for unifying the data structures and backend interfaces for the three evil clones ip_tables, ip6_tables and arp_tables. In an ideal world we would never have allowed this kind of copy+paste programming... but well, our world isn't (yet?) ideal. o introduce a new x_tables module o {ip,arp,ip6}_tables depend on this x_tables module o registration functions for tables, matches and targets are only wrappers around x_tables provided functions o all matches/targets that are used from ip_tables and ip6_tables are now implemented as xt_FOOBAR.c files and provide module aliases to ipt_FOOBAR and ip6t_FOOBAR o header files for xt_matches are in include/linux/netfilter/, include/linux/netfilter_{ipv4,ipv6} contains compatibility wrappers around the xt_FOOBAR.h headers Based on this patchset we're going to further unify the code, gradually getting rid of all the layer 3 specific assumptions. Signed-off-by: Harald Welte Signed-off-by: David S. Miller --- net/netfilter/xt_conntrack.c | 238 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 238 insertions(+) create mode 100644 net/netfilter/xt_conntrack.c (limited to 'net/netfilter/xt_conntrack.c') diff --git a/net/netfilter/xt_conntrack.c b/net/netfilter/xt_conntrack.c new file mode 100644 index 00000000000..ffdebc95eb9 --- /dev/null +++ b/net/netfilter/xt_conntrack.c @@ -0,0 +1,238 @@ +/* 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 +#include + +#if defined(CONFIG_IP_NF_CONNTRACK) || defined(CONFIG_IP_NF_CONNTRACK_MODULE) +#include +#include +#else +#include +#endif + +#include +#include + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Marc Boucher "); +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 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 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 int check(const char *tablename, + const void *ip, + void *matchinfo, + unsigned int matchsize, + unsigned int hook_mask) +{ + if (matchsize != XT_ALIGN(sizeof(struct xt_conntrack_info))) + return 0; + + return 1; +} + +static struct xt_match conntrack_match = { + .name = "conntrack", + .match = &match, + .checkentry = &check, + .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); -- cgit v1.2.3