129 lines
3.3 KiB
C
129 lines
3.3 KiB
C
/*
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* ebt_ip
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*
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* Authors:
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* Bart De Schuymer <bdschuym@pandora.be>
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*
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* April, 2002
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*
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* Changes:
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* added ip-sport and ip-dport
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* Innominate Security Technologies AG <mhopf@innominate.com>
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* September, 2002
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*/
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#include <linux/netfilter_bridge/ebtables.h>
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#include <linux/netfilter_bridge/ebt_ip.h>
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#include <linux/ip.h>
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#include <net/ip.h>
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#include <linux/in.h>
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#include <linux/module.h>
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struct tcpudphdr {
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__be16 src;
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__be16 dst;
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};
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static int ebt_filter_ip(const struct sk_buff *skb, const struct net_device *in,
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const struct net_device *out, const void *data,
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unsigned int datalen)
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{
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struct ebt_ip_info *info = (struct ebt_ip_info *)data;
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struct iphdr _iph, *ih;
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struct tcpudphdr _ports, *pptr;
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ih = skb_header_pointer(skb, 0, sizeof(_iph), &_iph);
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if (ih == NULL)
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return EBT_NOMATCH;
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if (info->bitmask & EBT_IP_TOS &&
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FWINV(info->tos != ih->tos, EBT_IP_TOS))
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return EBT_NOMATCH;
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if (info->bitmask & EBT_IP_SOURCE &&
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FWINV((ih->saddr & info->smsk) !=
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info->saddr, EBT_IP_SOURCE))
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return EBT_NOMATCH;
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if ((info->bitmask & EBT_IP_DEST) &&
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FWINV((ih->daddr & info->dmsk) !=
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info->daddr, EBT_IP_DEST))
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return EBT_NOMATCH;
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if (info->bitmask & EBT_IP_PROTO) {
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if (FWINV(info->protocol != ih->protocol, EBT_IP_PROTO))
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return EBT_NOMATCH;
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if (!(info->bitmask & EBT_IP_DPORT) &&
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!(info->bitmask & EBT_IP_SPORT))
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return EBT_MATCH;
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if (ntohs(ih->frag_off) & IP_OFFSET)
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return EBT_NOMATCH;
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pptr = skb_header_pointer(skb, ih->ihl*4,
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sizeof(_ports), &_ports);
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if (pptr == NULL)
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return EBT_NOMATCH;
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if (info->bitmask & EBT_IP_DPORT) {
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u32 dst = ntohs(pptr->dst);
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if (FWINV(dst < info->dport[0] ||
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dst > info->dport[1],
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EBT_IP_DPORT))
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return EBT_NOMATCH;
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}
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if (info->bitmask & EBT_IP_SPORT) {
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u32 src = ntohs(pptr->src);
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if (FWINV(src < info->sport[0] ||
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src > info->sport[1],
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EBT_IP_SPORT))
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return EBT_NOMATCH;
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}
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}
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return EBT_MATCH;
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}
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static int ebt_ip_check(const char *tablename, unsigned int hookmask,
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const struct ebt_entry *e, void *data, unsigned int datalen)
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{
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struct ebt_ip_info *info = (struct ebt_ip_info *)data;
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if (datalen != EBT_ALIGN(sizeof(struct ebt_ip_info)))
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return -EINVAL;
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if (e->ethproto != htons(ETH_P_IP) ||
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e->invflags & EBT_IPROTO)
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return -EINVAL;
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if (info->bitmask & ~EBT_IP_MASK || info->invflags & ~EBT_IP_MASK)
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return -EINVAL;
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if (info->bitmask & (EBT_IP_DPORT | EBT_IP_SPORT)) {
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if (info->invflags & EBT_IP_PROTO)
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return -EINVAL;
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if (info->protocol != IPPROTO_TCP &&
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info->protocol != IPPROTO_UDP &&
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info->protocol != IPPROTO_UDPLITE &&
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info->protocol != IPPROTO_SCTP &&
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info->protocol != IPPROTO_DCCP)
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return -EINVAL;
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}
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if (info->bitmask & EBT_IP_DPORT && info->dport[0] > info->dport[1])
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return -EINVAL;
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if (info->bitmask & EBT_IP_SPORT && info->sport[0] > info->sport[1])
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return -EINVAL;
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return 0;
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}
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static struct ebt_match filter_ip =
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{
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.name = EBT_IP_MATCH,
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.match = ebt_filter_ip,
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.check = ebt_ip_check,
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.me = THIS_MODULE,
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};
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static int __init ebt_ip_init(void)
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{
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return ebt_register_match(&filter_ip);
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}
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static void __exit ebt_ip_fini(void)
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{
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ebt_unregister_match(&filter_ip);
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}
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module_init(ebt_ip_init);
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module_exit(ebt_ip_fini);
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MODULE_LICENSE("GPL");
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