// SPDX-License-Identifier: GPL-2.0-only
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/*
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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/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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#include <linux/netfilter/x_tables.h>
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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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union pkthdr {
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struct {
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__be16 src;
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__be16 dst;
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} tcpudphdr;
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struct {
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u8 type;
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u8 code;
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} icmphdr;
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struct {
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u8 type;
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} igmphdr;
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};
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static bool
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ebt_ip_mt(const struct sk_buff *skb, struct xt_action_param *par)
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{
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const struct ebt_ip_info *info = par->matchinfo;
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const struct iphdr *ih;
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struct iphdr _iph;
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const union pkthdr *pptr;
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union pkthdr _pkthdr;
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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 false;
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if ((info->bitmask & EBT_IP_TOS) &&
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NF_INVF(info, EBT_IP_TOS, info->tos != ih->tos))
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return false;
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if ((info->bitmask & EBT_IP_SOURCE) &&
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NF_INVF(info, EBT_IP_SOURCE,
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(ih->saddr & info->smsk) != info->saddr))
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return false;
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if ((info->bitmask & EBT_IP_DEST) &&
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NF_INVF(info, EBT_IP_DEST,
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(ih->daddr & info->dmsk) != info->daddr))
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return false;
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if (info->bitmask & EBT_IP_PROTO) {
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if (NF_INVF(info, EBT_IP_PROTO, info->protocol != ih->protocol))
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return false;
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if (!(info->bitmask & (EBT_IP_DPORT | EBT_IP_SPORT |
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EBT_IP_ICMP | EBT_IP_IGMP)))
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return true;
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if (ntohs(ih->frag_off) & IP_OFFSET)
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return false;
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/* min icmp/igmp headersize is 4, so sizeof(_pkthdr) is ok. */
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pptr = skb_header_pointer(skb, ih->ihl*4,
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sizeof(_pkthdr), &_pkthdr);
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if (pptr == NULL)
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return false;
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if (info->bitmask & EBT_IP_DPORT) {
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u32 dst = ntohs(pptr->tcpudphdr.dst);
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if (NF_INVF(info, EBT_IP_DPORT,
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dst < info->dport[0] ||
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dst > info->dport[1]))
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return false;
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}
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if (info->bitmask & EBT_IP_SPORT) {
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u32 src = ntohs(pptr->tcpudphdr.src);
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if (NF_INVF(info, EBT_IP_SPORT,
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src < info->sport[0] ||
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src > info->sport[1]))
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return false;
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}
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if ((info->bitmask & EBT_IP_ICMP) &&
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NF_INVF(info, EBT_IP_ICMP,
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pptr->icmphdr.type < info->icmp_type[0] ||
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pptr->icmphdr.type > info->icmp_type[1] ||
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pptr->icmphdr.code < info->icmp_code[0] ||
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pptr->icmphdr.code > info->icmp_code[1]))
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return false;
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if ((info->bitmask & EBT_IP_IGMP) &&
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NF_INVF(info, EBT_IP_IGMP,
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pptr->igmphdr.type < info->igmp_type[0] ||
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pptr->igmphdr.type > info->igmp_type[1]))
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return false;
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}
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return true;
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}
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static int ebt_ip_mt_check(const struct xt_mtchk_param *par)
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{
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const struct ebt_ip_info *info = par->matchinfo;
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const struct ebt_entry *e = par->entryinfo;
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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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if (info->bitmask & EBT_IP_ICMP) {
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if ((info->invflags & EBT_IP_PROTO) ||
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info->protocol != IPPROTO_ICMP)
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return -EINVAL;
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if (info->icmp_type[0] > info->icmp_type[1] ||
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info->icmp_code[0] > info->icmp_code[1])
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return -EINVAL;
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}
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if (info->bitmask & EBT_IP_IGMP) {
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if ((info->invflags & EBT_IP_PROTO) ||
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info->protocol != IPPROTO_IGMP)
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return -EINVAL;
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if (info->igmp_type[0] > info->igmp_type[1])
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return -EINVAL;
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}
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return 0;
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}
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static struct xt_match ebt_ip_mt_reg __read_mostly = {
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.name = "ip",
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.revision = 0,
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.family = NFPROTO_BRIDGE,
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.match = ebt_ip_mt,
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.checkentry = ebt_ip_mt_check,
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.matchsize = sizeof(struct ebt_ip_info),
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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 xt_register_match(&ebt_ip_mt_reg);
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}
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static void __exit ebt_ip_fini(void)
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{
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xt_unregister_match(&ebt_ip_mt_reg);
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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_DESCRIPTION("Ebtables: IPv4 protocol packet match");
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MODULE_LICENSE("GPL");
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