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- /*
- * ebt_ip
- *
- * Authors:
- * Bart De Schuymer <bdschuym@pandora.be>
- *
- * April, 2002
- *
- * Changes:
- * added ip-sport and ip-dport
- * Innominate Security Technologies AG <mhopf@innominate.com>
- * September, 2002
- */
- #include <linux/ip.h>
- #include <net/ip.h>
- #include <linux/in.h>
- #include <linux/module.h>
- #include <linux/netfilter/x_tables.h>
- #include <linux/netfilter_bridge/ebtables.h>
- #include <linux/netfilter_bridge/ebt_ip.h>
- struct tcpudphdr {
- __be16 src;
- __be16 dst;
- };
- static bool
- ebt_ip_mt(const struct sk_buff *skb, struct xt_action_param *par)
- {
- const struct ebt_ip_info *info = par->matchinfo;
- const struct iphdr *ih;
- struct iphdr _iph;
- const struct tcpudphdr *pptr;
- struct tcpudphdr _ports;
- ih = skb_header_pointer(skb, 0, sizeof(_iph), &_iph);
- if (ih == NULL)
- return false;
- if (info->bitmask & EBT_IP_TOS &&
- FWINV(info->tos != ih->tos, EBT_IP_TOS))
- return false;
- if (info->bitmask & EBT_IP_SOURCE &&
- FWINV((ih->saddr & info->smsk) !=
- info->saddr, EBT_IP_SOURCE))
- return false;
- if ((info->bitmask & EBT_IP_DEST) &&
- FWINV((ih->daddr & info->dmsk) !=
- info->daddr, EBT_IP_DEST))
- return false;
- if (info->bitmask & EBT_IP_PROTO) {
- if (FWINV(info->protocol != ih->protocol, EBT_IP_PROTO))
- return false;
- if (!(info->bitmask & EBT_IP_DPORT) &&
- !(info->bitmask & EBT_IP_SPORT))
- return true;
- if (ntohs(ih->frag_off) & IP_OFFSET)
- return false;
- pptr = skb_header_pointer(skb, ih->ihl*4,
- sizeof(_ports), &_ports);
- if (pptr == NULL)
- return false;
- if (info->bitmask & EBT_IP_DPORT) {
- u32 dst = ntohs(pptr->dst);
- if (FWINV(dst < info->dport[0] ||
- dst > info->dport[1],
- EBT_IP_DPORT))
- return false;
- }
- if (info->bitmask & EBT_IP_SPORT) {
- u32 src = ntohs(pptr->src);
- if (FWINV(src < info->sport[0] ||
- src > info->sport[1],
- EBT_IP_SPORT))
- return false;
- }
- }
- return true;
- }
- static int ebt_ip_mt_check(const struct xt_mtchk_param *par)
- {
- const struct ebt_ip_info *info = par->matchinfo;
- const struct ebt_entry *e = par->entryinfo;
- if (e->ethproto != htons(ETH_P_IP) ||
- e->invflags & EBT_IPROTO)
- return -EINVAL;
- if (info->bitmask & ~EBT_IP_MASK || info->invflags & ~EBT_IP_MASK)
- return -EINVAL;
- if (info->bitmask & (EBT_IP_DPORT | EBT_IP_SPORT)) {
- if (info->invflags & EBT_IP_PROTO)
- return -EINVAL;
- if (info->protocol != IPPROTO_TCP &&
- info->protocol != IPPROTO_UDP &&
- info->protocol != IPPROTO_UDPLITE &&
- info->protocol != IPPROTO_SCTP &&
- info->protocol != IPPROTO_DCCP)
- return -EINVAL;
- }
- if (info->bitmask & EBT_IP_DPORT && info->dport[0] > info->dport[1])
- return -EINVAL;
- if (info->bitmask & EBT_IP_SPORT && info->sport[0] > info->sport[1])
- return -EINVAL;
- return 0;
- }
- static struct xt_match ebt_ip_mt_reg __read_mostly = {
- .name = "ip",
- .revision = 0,
- .family = NFPROTO_BRIDGE,
- .match = ebt_ip_mt,
- .checkentry = ebt_ip_mt_check,
- .matchsize = sizeof(struct ebt_ip_info),
- .me = THIS_MODULE,
- };
- static int __init ebt_ip_init(void)
- {
- return xt_register_match(&ebt_ip_mt_reg);
- }
- static void __exit ebt_ip_fini(void)
- {
- xt_unregister_match(&ebt_ip_mt_reg);
- }
- module_init(ebt_ip_init);
- module_exit(ebt_ip_fini);
- MODULE_DESCRIPTION("Ebtables: IPv4 protocol packet match");
- MODULE_LICENSE("GPL");
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