|  | /* | 
|  | *	xt_conntrack - Netfilter module to match connection tracking | 
|  | *	information. (Superset of Rusty's minimalistic state match.) | 
|  | * | 
|  | *	(C) 2001  Marc Boucher (marc@mbsi.ca). | 
|  | *	(C) 2006-2012 Patrick McHardy <kaber@trash.net> | 
|  | *	Copyright © CC Computer Consultants GmbH, 2007 - 2008 | 
|  | * | 
|  | *	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. | 
|  | */ | 
|  | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt | 
|  | #include <linux/module.h> | 
|  | #include <linux/skbuff.h> | 
|  | #include <net/ipv6.h> | 
|  | #include <linux/netfilter/x_tables.h> | 
|  | #include <linux/netfilter/xt_conntrack.h> | 
|  | #include <net/netfilter/nf_conntrack.h> | 
|  |  | 
|  | MODULE_LICENSE("GPL"); | 
|  | MODULE_AUTHOR("Marc Boucher <marc@mbsi.ca>"); | 
|  | MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>"); | 
|  | MODULE_DESCRIPTION("Xtables: connection tracking state match"); | 
|  | MODULE_ALIAS("ipt_conntrack"); | 
|  | MODULE_ALIAS("ip6t_conntrack"); | 
|  |  | 
|  | static bool | 
|  | conntrack_addrcmp(const union nf_inet_addr *kaddr, | 
|  | const union nf_inet_addr *uaddr, | 
|  | const union nf_inet_addr *umask, unsigned int l3proto) | 
|  | { | 
|  | if (l3proto == NFPROTO_IPV4) | 
|  | return ((kaddr->ip ^ uaddr->ip) & umask->ip) == 0; | 
|  | else if (l3proto == NFPROTO_IPV6) | 
|  | return ipv6_masked_addr_cmp(&kaddr->in6, &umask->in6, | 
|  | &uaddr->in6) == 0; | 
|  | else | 
|  | return false; | 
|  | } | 
|  |  | 
|  | static inline bool | 
|  | conntrack_mt_origsrc(const struct nf_conn *ct, | 
|  | const struct xt_conntrack_mtinfo2 *info, | 
|  | u_int8_t family) | 
|  | { | 
|  | return conntrack_addrcmp(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3, | 
|  | &info->origsrc_addr, &info->origsrc_mask, family); | 
|  | } | 
|  |  | 
|  | static inline bool | 
|  | conntrack_mt_origdst(const struct nf_conn *ct, | 
|  | const struct xt_conntrack_mtinfo2 *info, | 
|  | u_int8_t family) | 
|  | { | 
|  | return conntrack_addrcmp(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.u3, | 
|  | &info->origdst_addr, &info->origdst_mask, family); | 
|  | } | 
|  |  | 
|  | static inline bool | 
|  | conntrack_mt_replsrc(const struct nf_conn *ct, | 
|  | const struct xt_conntrack_mtinfo2 *info, | 
|  | u_int8_t family) | 
|  | { | 
|  | return conntrack_addrcmp(&ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.u3, | 
|  | &info->replsrc_addr, &info->replsrc_mask, family); | 
|  | } | 
|  |  | 
|  | static inline bool | 
|  | conntrack_mt_repldst(const struct nf_conn *ct, | 
|  | const struct xt_conntrack_mtinfo2 *info, | 
|  | u_int8_t family) | 
|  | { | 
|  | return conntrack_addrcmp(&ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u3, | 
|  | &info->repldst_addr, &info->repldst_mask, family); | 
|  | } | 
|  |  | 
|  | static inline bool | 
|  | ct_proto_port_check(const struct xt_conntrack_mtinfo2 *info, | 
|  | const struct nf_conn *ct) | 
|  | { | 
|  | const struct nf_conntrack_tuple *tuple; | 
|  |  | 
|  | tuple = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple; | 
|  | if ((info->match_flags & XT_CONNTRACK_PROTO) && | 
|  | (nf_ct_protonum(ct) == info->l4proto) ^ | 
|  | !(info->invert_flags & XT_CONNTRACK_PROTO)) | 
|  | return false; | 
|  |  | 
|  | /* Shortcut to match all recognized protocols by using ->src.all. */ | 
|  | if ((info->match_flags & XT_CONNTRACK_ORIGSRC_PORT) && | 
|  | (tuple->src.u.all == info->origsrc_port) ^ | 
|  | !(info->invert_flags & XT_CONNTRACK_ORIGSRC_PORT)) | 
|  | return false; | 
|  |  | 
|  | if ((info->match_flags & XT_CONNTRACK_ORIGDST_PORT) && | 
|  | (tuple->dst.u.all == info->origdst_port) ^ | 
|  | !(info->invert_flags & XT_CONNTRACK_ORIGDST_PORT)) | 
|  | return false; | 
|  |  | 
|  | tuple = &ct->tuplehash[IP_CT_DIR_REPLY].tuple; | 
|  |  | 
|  | if ((info->match_flags & XT_CONNTRACK_REPLSRC_PORT) && | 
|  | (tuple->src.u.all == info->replsrc_port) ^ | 
|  | !(info->invert_flags & XT_CONNTRACK_REPLSRC_PORT)) | 
|  | return false; | 
|  |  | 
|  | if ((info->match_flags & XT_CONNTRACK_REPLDST_PORT) && | 
|  | (tuple->dst.u.all == info->repldst_port) ^ | 
|  | !(info->invert_flags & XT_CONNTRACK_REPLDST_PORT)) | 
|  | return false; | 
|  |  | 
|  | return true; | 
|  | } | 
|  |  | 
|  | static inline bool | 
|  | port_match(u16 min, u16 max, u16 port, bool invert) | 
|  | { | 
|  | return (port >= min && port <= max) ^ invert; | 
|  | } | 
|  |  | 
|  | static inline bool | 
|  | ct_proto_port_check_v3(const struct xt_conntrack_mtinfo3 *info, | 
|  | const struct nf_conn *ct) | 
|  | { | 
|  | const struct nf_conntrack_tuple *tuple; | 
|  |  | 
|  | tuple = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple; | 
|  | if ((info->match_flags & XT_CONNTRACK_PROTO) && | 
|  | (nf_ct_protonum(ct) == info->l4proto) ^ | 
|  | !(info->invert_flags & XT_CONNTRACK_PROTO)) | 
|  | return false; | 
|  |  | 
|  | /* Shortcut to match all recognized protocols by using ->src.all. */ | 
|  | if ((info->match_flags & XT_CONNTRACK_ORIGSRC_PORT) && | 
|  | !port_match(info->origsrc_port, info->origsrc_port_high, | 
|  | ntohs(tuple->src.u.all), | 
|  | info->invert_flags & XT_CONNTRACK_ORIGSRC_PORT)) | 
|  | return false; | 
|  |  | 
|  | if ((info->match_flags & XT_CONNTRACK_ORIGDST_PORT) && | 
|  | !port_match(info->origdst_port, info->origdst_port_high, | 
|  | ntohs(tuple->dst.u.all), | 
|  | info->invert_flags & XT_CONNTRACK_ORIGDST_PORT)) | 
|  | return false; | 
|  |  | 
|  | tuple = &ct->tuplehash[IP_CT_DIR_REPLY].tuple; | 
|  |  | 
|  | if ((info->match_flags & XT_CONNTRACK_REPLSRC_PORT) && | 
|  | !port_match(info->replsrc_port, info->replsrc_port_high, | 
|  | ntohs(tuple->src.u.all), | 
|  | info->invert_flags & XT_CONNTRACK_REPLSRC_PORT)) | 
|  | return false; | 
|  |  | 
|  | if ((info->match_flags & XT_CONNTRACK_REPLDST_PORT) && | 
|  | !port_match(info->repldst_port, info->repldst_port_high, | 
|  | ntohs(tuple->dst.u.all), | 
|  | info->invert_flags & XT_CONNTRACK_REPLDST_PORT)) | 
|  | return false; | 
|  |  | 
|  | return true; | 
|  | } | 
|  |  | 
|  | static bool | 
|  | conntrack_mt(const struct sk_buff *skb, struct xt_action_param *par, | 
|  | u16 state_mask, u16 status_mask) | 
|  | { | 
|  | const struct xt_conntrack_mtinfo2 *info = par->matchinfo; | 
|  | enum ip_conntrack_info ctinfo; | 
|  | const struct nf_conn *ct; | 
|  | unsigned int statebit; | 
|  |  | 
|  | ct = nf_ct_get(skb, &ctinfo); | 
|  |  | 
|  | if (ct) | 
|  | statebit = XT_CONNTRACK_STATE_BIT(ctinfo); | 
|  | else if (ctinfo == IP_CT_UNTRACKED) | 
|  | statebit = XT_CONNTRACK_STATE_UNTRACKED; | 
|  | else | 
|  | statebit = XT_CONNTRACK_STATE_INVALID; | 
|  |  | 
|  | if (info->match_flags & XT_CONNTRACK_STATE) { | 
|  | if (ct != NULL) { | 
|  | 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 (!!(state_mask & statebit) ^ | 
|  | !(info->invert_flags & XT_CONNTRACK_STATE)) | 
|  | return false; | 
|  | } | 
|  |  | 
|  | if (ct == NULL) | 
|  | return info->match_flags & XT_CONNTRACK_STATE; | 
|  | if ((info->match_flags & XT_CONNTRACK_DIRECTION) && | 
|  | (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL) ^ | 
|  | !(info->invert_flags & XT_CONNTRACK_DIRECTION)) | 
|  | return false; | 
|  |  | 
|  | if (info->match_flags & XT_CONNTRACK_ORIGSRC) | 
|  | if (conntrack_mt_origsrc(ct, info, xt_family(par)) ^ | 
|  | !(info->invert_flags & XT_CONNTRACK_ORIGSRC)) | 
|  | return false; | 
|  |  | 
|  | if (info->match_flags & XT_CONNTRACK_ORIGDST) | 
|  | if (conntrack_mt_origdst(ct, info, xt_family(par)) ^ | 
|  | !(info->invert_flags & XT_CONNTRACK_ORIGDST)) | 
|  | return false; | 
|  |  | 
|  | if (info->match_flags & XT_CONNTRACK_REPLSRC) | 
|  | if (conntrack_mt_replsrc(ct, info, xt_family(par)) ^ | 
|  | !(info->invert_flags & XT_CONNTRACK_REPLSRC)) | 
|  | return false; | 
|  |  | 
|  | if (info->match_flags & XT_CONNTRACK_REPLDST) | 
|  | if (conntrack_mt_repldst(ct, info, xt_family(par)) ^ | 
|  | !(info->invert_flags & XT_CONNTRACK_REPLDST)) | 
|  | return false; | 
|  |  | 
|  | if (par->match->revision != 3) { | 
|  | if (!ct_proto_port_check(info, ct)) | 
|  | return false; | 
|  | } else { | 
|  | if (!ct_proto_port_check_v3(par->matchinfo, ct)) | 
|  | return false; | 
|  | } | 
|  |  | 
|  | if ((info->match_flags & XT_CONNTRACK_STATUS) && | 
|  | (!!(status_mask & ct->status) ^ | 
|  | !(info->invert_flags & XT_CONNTRACK_STATUS))) | 
|  | return false; | 
|  |  | 
|  | if (info->match_flags & XT_CONNTRACK_EXPIRES) { | 
|  | unsigned long expires = nf_ct_expires(ct) / HZ; | 
|  |  | 
|  | if ((expires >= info->expires_min && | 
|  | expires <= info->expires_max) ^ | 
|  | !(info->invert_flags & XT_CONNTRACK_EXPIRES)) | 
|  | return false; | 
|  | } | 
|  | return true; | 
|  | } | 
|  |  | 
|  | static bool | 
|  | conntrack_mt_v1(const struct sk_buff *skb, struct xt_action_param *par) | 
|  | { | 
|  | const struct xt_conntrack_mtinfo1 *info = par->matchinfo; | 
|  |  | 
|  | return conntrack_mt(skb, par, info->state_mask, info->status_mask); | 
|  | } | 
|  |  | 
|  | static bool | 
|  | conntrack_mt_v2(const struct sk_buff *skb, struct xt_action_param *par) | 
|  | { | 
|  | const struct xt_conntrack_mtinfo2 *info = par->matchinfo; | 
|  |  | 
|  | return conntrack_mt(skb, par, info->state_mask, info->status_mask); | 
|  | } | 
|  |  | 
|  | static bool | 
|  | conntrack_mt_v3(const struct sk_buff *skb, struct xt_action_param *par) | 
|  | { | 
|  | const struct xt_conntrack_mtinfo3 *info = par->matchinfo; | 
|  |  | 
|  | return conntrack_mt(skb, par, info->state_mask, info->status_mask); | 
|  | } | 
|  |  | 
|  | static int conntrack_mt_check(const struct xt_mtchk_param *par) | 
|  | { | 
|  | int ret; | 
|  |  | 
|  | ret = nf_ct_netns_get(par->net, par->family); | 
|  | if (ret < 0) | 
|  | pr_info("cannot load conntrack support for proto=%u\n", | 
|  | par->family); | 
|  | return ret; | 
|  | } | 
|  |  | 
|  | static void conntrack_mt_destroy(const struct xt_mtdtor_param *par) | 
|  | { | 
|  | nf_ct_netns_put(par->net, par->family); | 
|  | } | 
|  |  | 
|  | static struct xt_match conntrack_mt_reg[] __read_mostly = { | 
|  | { | 
|  | .name       = "conntrack", | 
|  | .revision   = 1, | 
|  | .family     = NFPROTO_UNSPEC, | 
|  | .matchsize  = sizeof(struct xt_conntrack_mtinfo1), | 
|  | .match      = conntrack_mt_v1, | 
|  | .checkentry = conntrack_mt_check, | 
|  | .destroy    = conntrack_mt_destroy, | 
|  | .me         = THIS_MODULE, | 
|  | }, | 
|  | { | 
|  | .name       = "conntrack", | 
|  | .revision   = 2, | 
|  | .family     = NFPROTO_UNSPEC, | 
|  | .matchsize  = sizeof(struct xt_conntrack_mtinfo2), | 
|  | .match      = conntrack_mt_v2, | 
|  | .checkentry = conntrack_mt_check, | 
|  | .destroy    = conntrack_mt_destroy, | 
|  | .me         = THIS_MODULE, | 
|  | }, | 
|  | { | 
|  | .name       = "conntrack", | 
|  | .revision   = 3, | 
|  | .family     = NFPROTO_UNSPEC, | 
|  | .matchsize  = sizeof(struct xt_conntrack_mtinfo3), | 
|  | .match      = conntrack_mt_v3, | 
|  | .checkentry = conntrack_mt_check, | 
|  | .destroy    = conntrack_mt_destroy, | 
|  | .me         = THIS_MODULE, | 
|  | }, | 
|  | }; | 
|  |  | 
|  | static int __init conntrack_mt_init(void) | 
|  | { | 
|  | return xt_register_matches(conntrack_mt_reg, | 
|  | ARRAY_SIZE(conntrack_mt_reg)); | 
|  | } | 
|  |  | 
|  | static void __exit conntrack_mt_exit(void) | 
|  | { | 
|  | xt_unregister_matches(conntrack_mt_reg, ARRAY_SIZE(conntrack_mt_reg)); | 
|  | } | 
|  |  | 
|  | module_init(conntrack_mt_init); | 
|  | module_exit(conntrack_mt_exit); |