fc0e3df4f0
This will cause trouble once CONFIG_COMPAT support is added to ebtables. xt_compat_*_offset() calculate the kernel/userland structure size delta using: XT_ALIGN(size) - COMPAT_XT_ALIGN(size) If the match/target sizes are aligned at registration time, delta is always zero. Should have zero effect for existing systems: xtables uses XT_ALIGN() whenever it deals with match/target sizes. Signed-off-by: Florian Westphal <fwestphal@astaro.com> Signed-off-by: Patrick McHardy <kaber@trash.net>
88 lines
2 KiB
C
88 lines
2 KiB
C
/*
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* ebt_snat
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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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* June, 2002
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*
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*/
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#include <linux/module.h>
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#include <net/sock.h>
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#include <linux/if_arp.h>
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#include <net/arp.h>
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#include <linux/netfilter.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_nat.h>
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static unsigned int
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ebt_snat_tg(struct sk_buff *skb, const struct xt_target_param *par)
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{
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const struct ebt_nat_info *info = par->targinfo;
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if (!skb_make_writable(skb, 0))
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return EBT_DROP;
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memcpy(eth_hdr(skb)->h_source, info->mac, ETH_ALEN);
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if (!(info->target & NAT_ARP_BIT) &&
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eth_hdr(skb)->h_proto == htons(ETH_P_ARP)) {
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const struct arphdr *ap;
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struct arphdr _ah;
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ap = skb_header_pointer(skb, 0, sizeof(_ah), &_ah);
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if (ap == NULL)
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return EBT_DROP;
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if (ap->ar_hln != ETH_ALEN)
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goto out;
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if (skb_store_bits(skb, sizeof(_ah), info->mac,ETH_ALEN))
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return EBT_DROP;
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}
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out:
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return info->target | ~EBT_VERDICT_BITS;
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}
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static bool ebt_snat_tg_check(const struct xt_tgchk_param *par)
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{
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const struct ebt_nat_info *info = par->targinfo;
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int tmp;
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tmp = info->target | ~EBT_VERDICT_BITS;
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if (BASE_CHAIN && tmp == EBT_RETURN)
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return false;
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if (tmp < -NUM_STANDARD_TARGETS || tmp >= 0)
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return false;
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tmp = info->target | EBT_VERDICT_BITS;
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if ((tmp & ~NAT_ARP_BIT) != ~NAT_ARP_BIT)
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return false;
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return true;
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}
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static struct xt_target ebt_snat_tg_reg __read_mostly = {
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.name = "snat",
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.revision = 0,
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.family = NFPROTO_BRIDGE,
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.table = "nat",
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.hooks = (1 << NF_BR_NUMHOOKS) | (1 << NF_BR_POST_ROUTING),
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.target = ebt_snat_tg,
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.checkentry = ebt_snat_tg_check,
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.targetsize = sizeof(struct ebt_nat_info),
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.me = THIS_MODULE,
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};
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static int __init ebt_snat_init(void)
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{
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return xt_register_target(&ebt_snat_tg_reg);
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}
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static void __exit ebt_snat_fini(void)
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{
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xt_unregister_target(&ebt_snat_tg_reg);
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}
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module_init(ebt_snat_init);
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module_exit(ebt_snat_fini);
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MODULE_DESCRIPTION("Ebtables: Source MAC address translation");
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MODULE_LICENSE("GPL");
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