xt_multiport.rar_As One

/* 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. */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #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>"); MODULE_DESCRIPTION("Xtables: multiple port matching for TCP, UDP, UDP-Lite, SCTP and DCCP"); MODULE_ALIAS("ipt_multiport"); MODULE_ALIAS("ip6t_multiport"); /* Returns 1 if the port is matched by the test, 0 otherwise. */ static inline bool 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]; pr_debug("src or dst matches with %d-%d?\n", s, e); if (minfo->flags == XT_MULTIPORT_SOURCE && src >= s && src <= e) return true ^ minfo->invert; if (minfo->flags == XT_MULTIPORT_DESTINATION && dst >= s && dst <= e) return true ^ minfo->invert; if (minfo->flags == XT_MULTIPORT_EITHER && ((dst >= s && dst <= e) || (src >= s && src <= e))) return true ^ minfo->invert; } else { /* exact port matching */ pr_debug("src or dst matches with %d?\n", s); if (minfo->flags == XT_MULTIPORT_SOURCE && src == s) return true ^ minfo->invert; if (minfo->flags == XT_MULTIPORT_DESTINATION && dst == s) return true ^ minfo->invert; if (minfo->flags == XT_MULTIPORT_EITHER && (src == s || dst == s)) return true ^ minfo->invert; } } return minfo->invert; } static bool multiport_mt(const struct sk_buff *skb, struct xt_action_param *par) { const __be16 *pptr; __be16 _ports[2]; const struct xt_multiport_v1 *multiinfo = par->matchinfo; if (par->fragoff != 0) return false; pptr = skb_header_pointer(skb, par->thoff, sizeof(_ports), _ports); if (pptr == NULL) { /* We've been asked to examine this packet, and we * can't. Hence, no choice but to drop. */ pr_debug("Dropping evil offset=0 tinygram.\n"); par->hotdrop = true; return false; } return ports_match_v1(multiinfo, ntohs(pptr[0]), ntohs(pptr[1])); } static inline bool check(u_int16_t proto, u_int8_t ip_invflags, u_int8_t match_flags, u_int8_t count) { /* Must specify supported protocol, no unknown flags or bad count */ return (proto == IPPROTO_TCP || proto == IPPROTO_UDP || proto == IPPROTO_UDPLITE || proto == IPPROTO_SCTP || proto == IPPROTO_DCCP) && !(ip_invflags & XT_INV_PROTO) && (match_flags == XT_MULTIPORT_SOURCE || match_flags == XT_MULTIPORT_DESTINATION || match_flags == XT_MULTIPORT_EITHER) && count <= XT_MULTI_PORTS; } static int multiport_mt_check(const struct xt_mtchk_param *par) { const struct ipt_ip *ip = par->entryinfo; const struct xt_multiport_v1 *multiinfo = par->matchinfo; return check(ip->proto, ip->invflags, multiinfo->flags, multiinfo->count) ? 0 : -EINVAL; } static int multiport_mt6_check(const struct xt_mtchk_param *par) { const struct ip6t_ip6 *ip = par->entryinfo; const struct xt_multiport_v1 *multiinfo = par->matchinfo; return check(ip->proto, ip->invflags, multiinfo->flags, multiinfo->count) ? 0 : -EINVAL; } static struct xt_match multiport_mt_reg[] __read_mostly = { { .name = "multiport", .family = NFPROTO_IPV4, .revision = 1, .checkentry = multiport_mt_check, .match = multiport_mt, .matchsize = sizeof(struct xt_multiport_v1), .me = THIS_MODULE, }, { .name = "multiport", .family = NFPROTO_IPV6, .revision = 1, .checkentry = multiport_mt6_check, .match = multiport_mt, .matchsize = sizeof(struct xt_multiport_v1), .me = THIS_MODULE, }, }; static int __init multiport_mt_init(void) { return xt_register_matches(multiport_mt_reg, ARRAY_SIZE(multiport_mt_reg)); } static void __exit multiport_mt_exit(void) { xt_unregister_matches(multiport_mt_reg, ARRAY_SIZE(multiport_mt_reg)); } module_init(multiport_mt_init); module_exit(multiport_mt_exit);