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[/] [or1k/] [trunk/] [linux/] [linux-2.4/] [net/] [ipv4/] [netfilter/] [ipt_multiport.c] - Rev 1765
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/* Kernel module to match one of a list of TCP/UDP ports: ports are in the same place so we can treat them as equal. */ #include <linux/module.h> #include <linux/types.h> #include <linux/udp.h> #include <linux/skbuff.h> #include <linux/netfilter_ipv4/ipt_multiport.h> #include <linux/netfilter_ipv4/ip_tables.h> #if 0 #define duprintf(format, args...) printk(format , ## args) #else #define duprintf(format, args...) #endif /* Returns 1 if the port is matched by the test, 0 otherwise. */ static inline int ports_match(const u_int16_t *portlist, enum ipt_multiport_flags flags, u_int8_t count, u_int16_t src, u_int16_t dst) { unsigned int i; for (i=0; i<count; i++) { if (flags != IPT_MULTIPORT_DESTINATION && portlist[i] == src) return 1; if (flags != IPT_MULTIPORT_SOURCE && portlist[i] == dst) return 1; } return 0; } static int match(const struct sk_buff *skb, const struct net_device *in, const struct net_device *out, const void *matchinfo, int offset, const void *hdr, u_int16_t datalen, int *hotdrop) { const struct udphdr *udp = hdr; const struct ipt_multiport *multiinfo = matchinfo; /* Must be big enough to read ports. */ if (offset == 0 && datalen < sizeof(struct udphdr)) { /* We've been asked to examine this packet, and we can't. Hence, no choice but to drop. */ duprintf("ipt_multiport:" " Dropping evil offset=0 tinygram.\n"); *hotdrop = 1; return 0; } /* Must not be a fragment. */ return !offset && ports_match(multiinfo->ports, multiinfo->flags, multiinfo->count, ntohs(udp->source), ntohs(udp->dest)); } /* Called when user tries to insert an entry of this type. */ static int checkentry(const char *tablename, const struct ipt_ip *ip, void *matchinfo, unsigned int matchsize, unsigned int hook_mask) { const struct ipt_multiport *multiinfo = matchinfo; if (matchsize != IPT_ALIGN(sizeof(struct ipt_multiport))) return 0; /* Must specify proto == TCP/UDP, no unknown flags or bad count */ return (ip->proto == IPPROTO_TCP || ip->proto == IPPROTO_UDP) && !(ip->invflags & IPT_INV_PROTO) && matchsize == IPT_ALIGN(sizeof(struct ipt_multiport)) && (multiinfo->flags == IPT_MULTIPORT_SOURCE || multiinfo->flags == IPT_MULTIPORT_DESTINATION || multiinfo->flags == IPT_MULTIPORT_EITHER) && multiinfo->count <= IPT_MULTI_PORTS; } static struct ipt_match multiport_match = { { NULL, NULL }, "multiport", &match, &checkentry, NULL, THIS_MODULE }; static int __init init(void) { return ipt_register_match(&multiport_match); } static void __exit fini(void) { ipt_unregister_match(&multiport_match); } module_init(init); module_exit(fini); MODULE_LICENSE("GPL");