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net/netfilter/xt_multiport.c
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/* Kernel module to match one of a list of TCP/UDP(-Lite)/SCTP/DCCP ports: ports are in the same place so we can treat them as equal. */ |
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/* (C) 1999-2001 Paul `Rusty' Russell * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org> * * 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. */ |
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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#include <linux/module.h> #include <linux/types.h> #include <linux/udp.h> #include <linux/skbuff.h> #include <linux/in.h> #include <linux/netfilter/xt_multiport.h> #include <linux/netfilter/x_tables.h> #include <linux/netfilter_ipv4/ip_tables.h> #include <linux/netfilter_ipv6/ip6_tables.h> MODULE_LICENSE("GPL"); MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>"); |
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MODULE_DESCRIPTION("Xtables: multiple port matching for TCP, UDP, UDP-Lite, SCTP and DCCP"); |
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MODULE_ALIAS("ipt_multiport"); MODULE_ALIAS("ip6t_multiport"); |
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/* Returns 1 if the port is matched by the test, 0 otherwise. */ |
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static inline bool |
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ports_match_v1(const struct xt_multiport_v1 *minfo, u_int16_t src, u_int16_t dst) { unsigned int i; u_int16_t s, e; for (i = 0; i < minfo->count; i++) { s = minfo->ports[i]; if (minfo->pflags[i]) { /* range port matching */ e = minfo->ports[++i]; |
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pr_debug("src or dst matches with %d-%d? ", s, e); |
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if (minfo->flags == XT_MULTIPORT_SOURCE && src >= s && src <= e) |
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return true ^ minfo->invert; |
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if (minfo->flags == XT_MULTIPORT_DESTINATION && dst >= s && dst <= e) |
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return true ^ minfo->invert; |
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if (minfo->flags == XT_MULTIPORT_EITHER && ((dst >= s && dst <= e) || (src >= s && src <= e))) |
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return true ^ minfo->invert; |
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} else { /* exact port matching */ |
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pr_debug("src or dst matches with %d? ", s); |
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if (minfo->flags == XT_MULTIPORT_SOURCE && src == s) |
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return true ^ minfo->invert; |
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if (minfo->flags == XT_MULTIPORT_DESTINATION && dst == s) |
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return true ^ minfo->invert; |
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if (minfo->flags == XT_MULTIPORT_EITHER && (src == s || dst == s)) |
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return true ^ minfo->invert; |
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} } |
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return minfo->invert; |
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} |
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static bool |
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multiport_mt(const struct sk_buff *skb, struct xt_action_param *par) |
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{ |
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const __be16 *pptr; __be16 _ports[2]; |
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const struct xt_multiport_v1 *multiinfo = par->matchinfo; |
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if (par->fragoff != 0) |
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return false; |
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pptr = skb_header_pointer(skb, par->thoff, sizeof(_ports), _ports); |
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if (pptr == NULL) { /* We've been asked to examine this packet, and we * can't. Hence, no choice but to drop. */ |
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pr_debug("Dropping evil offset=0 tinygram. "); |
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par->hotdrop = true; |
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return false; |
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} return ports_match_v1(multiinfo, ntohs(pptr[0]), ntohs(pptr[1])); } |
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static inline bool |
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check(u_int16_t proto, u_int8_t ip_invflags, u_int8_t match_flags, u_int8_t count) { |
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/* Must specify supported protocol, no unknown flags or bad count */ return (proto == IPPROTO_TCP || proto == IPPROTO_UDP |
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|| proto == IPPROTO_UDPLITE |
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|| proto == IPPROTO_SCTP || proto == IPPROTO_DCCP) |
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&& !(ip_invflags & XT_INV_PROTO) && (match_flags == XT_MULTIPORT_SOURCE || match_flags == XT_MULTIPORT_DESTINATION || match_flags == XT_MULTIPORT_EITHER) && count <= XT_MULTI_PORTS; } |
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static int multiport_mt_check(const struct xt_mtchk_param *par) |
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{ |
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const struct ipt_ip *ip = par->entryinfo; const struct xt_multiport_v1 *multiinfo = par->matchinfo; |
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return check(ip->proto, ip->invflags, multiinfo->flags, |
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multiinfo->count) ? 0 : -EINVAL; |
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} |
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static int multiport_mt6_check(const struct xt_mtchk_param *par) |
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{ |
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const struct ip6t_ip6 *ip = par->entryinfo; const struct xt_multiport_v1 *multiinfo = par->matchinfo; |
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return check(ip->proto, ip->invflags, multiinfo->flags, |
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multiinfo->count) ? 0 : -EINVAL; |
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} |
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static struct xt_match multiport_mt_reg[] __read_mostly = { |
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{ .name = "multiport", |
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.family = NFPROTO_IPV4, |
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.revision = 1, |
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.checkentry = multiport_mt_check, .match = multiport_mt, |
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.matchsize = sizeof(struct xt_multiport_v1), .me = THIS_MODULE, }, { .name = "multiport", |
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.family = NFPROTO_IPV6, |
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.revision = 1, |
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.checkentry = multiport_mt6_check, .match = multiport_mt, |
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.matchsize = sizeof(struct xt_multiport_v1), .me = THIS_MODULE, }, |
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}; |
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static int __init multiport_mt_init(void) |
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{ |
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return xt_register_matches(multiport_mt_reg, ARRAY_SIZE(multiport_mt_reg)); |
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} |
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static void __exit multiport_mt_exit(void) |
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{ |
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xt_unregister_matches(multiport_mt_reg, ARRAY_SIZE(multiport_mt_reg)); |
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} |
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module_init(multiport_mt_init); module_exit(multiport_mt_exit); |