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net/netfilter/xt_conntrack.c
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/* * 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 ", 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); |