projects / linux-block.git / blame
| Commit | Line | Data |
|---|---|---|
| 09c434b8 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
| 1da177e4 LT |
2 | /* |
| 3 | * ebt_snat | |
| 4 | * | |
| 5 | * Authors: | |
| 6 | * Bart De Schuymer <bdschuym@pandora.be> | |
| 7 | * | |
| 8 | * June, 2002 | |
| 9 | * | |
| 10 | */ | |
| 1da177e4 LT |
11 | #include <linux/module.h> |
| 12 | #include <net/sock.h> | |
| d12cdc3c BDS |
13 | #include <linux/if_arp.h> |
| 14 | #include <net/arp.h> | |
| 18219d3f JE |
15 | #include <linux/netfilter.h> |
| 16 | #include <linux/netfilter/x_tables.h> | |
| 17 | #include <linux/netfilter_bridge/ebtables.h> | |
| 18 | #include <linux/netfilter_bridge/ebt_nat.h> | |
| 1da177e4 | 19 | |
| 2d06d4a5 | 20 | static unsigned int |
| 4b560b44 | 21 | ebt_snat_tg(struct sk_buff *skb, const struct xt_action_param *par) |
| 1da177e4 | 22 | { |
| 7eb35586 | 23 | const struct ebt_nat_info *info = par->targinfo; |
| 1da177e4 | 24 | |
| eb1197bc | 25 | if (!skb_make_writable(skb, 0)) |
| 1b04ab45 | 26 | return EBT_DROP; |
| 1da177e4 | 27 | |
| 04091142 | 28 | ether_addr_copy(eth_hdr(skb)->h_source, info->mac); |
| d12cdc3c | 29 | if (!(info->target & NAT_ARP_BIT) && |
| 3db05fea | 30 | eth_hdr(skb)->h_proto == htons(ETH_P_ARP)) { |
| abfdf1c4 JE |
31 | const struct arphdr *ap; |
| 32 | struct arphdr _ah; | |
| d12cdc3c | 33 | |
| 3db05fea | 34 | ap = skb_header_pointer(skb, 0, sizeof(_ah), &_ah); |
| d12cdc3c BDS |
35 | if (ap == NULL) |
| 36 | return EBT_DROP; | |
| 37 | if (ap->ar_hln != ETH_ALEN) | |
| 38 | goto out; | |
| 31a5b837 | 39 | if (skb_store_bits(skb, sizeof(_ah), info->mac, ETH_ALEN)) |
| d12cdc3c BDS |
40 | return EBT_DROP; |
| 41 | } | |
| 42 | out: | |
| 43 | return info->target | ~EBT_VERDICT_BITS; | |
| 1da177e4 LT |
44 | } |
| 45 | ||
| 135367b8 | 46 | static int ebt_snat_tg_check(const struct xt_tgchk_param *par) |
| 1da177e4 | 47 | { |
| af5d6dc2 | 48 | const struct ebt_nat_info *info = par->targinfo; |
| d12cdc3c | 49 | int tmp; |
| 1da177e4 | 50 | |
| d12cdc3c BDS |
51 | tmp = info->target | ~EBT_VERDICT_BITS; |
| 52 | if (BASE_CHAIN && tmp == EBT_RETURN) | |
| d6b00a53 | 53 | return -EINVAL; |
| d12cdc3c | 54 | |
| e15b9c50 | 55 | if (ebt_invalid_target(tmp)) |
| d6b00a53 | 56 | return -EINVAL; |
| d12cdc3c BDS |
57 | tmp = info->target | EBT_VERDICT_BITS; |
| 58 | if ((tmp & ~NAT_ARP_BIT) != ~NAT_ARP_BIT) | |
| d6b00a53 JE |
59 | return -EINVAL; |
| 60 | return 0; | |
| 1da177e4 LT |
61 | } |
| 62 | ||
| 043ef46c JE |
63 | static struct xt_target ebt_snat_tg_reg __read_mostly = { |
| 64 | .name = "snat", | |
| 001a18d3 JE |
65 | .revision = 0, |
| 66 | .family = NFPROTO_BRIDGE, | |
| f2ff525c JE |
67 | .table = "nat", |
| 68 | .hooks = (1 << NF_BR_NUMHOOKS) | (1 << NF_BR_POST_ROUTING), | |
| 2d06d4a5 JE |
69 | .target = ebt_snat_tg, |
| 70 | .checkentry = ebt_snat_tg_check, | |
| fc0e3df4 | 71 | .targetsize = sizeof(struct ebt_nat_info), |
| 1da177e4 LT |
72 | .me = THIS_MODULE, |
| 73 | }; | |
| 74 | ||
| 65b4b4e8 | 75 | static int __init ebt_snat_init(void) |
| 1da177e4 | 76 | { |
| 043ef46c | 77 | return xt_register_target(&ebt_snat_tg_reg); |
| 1da177e4 LT |
78 | } |
| 79 | ||
| 65b4b4e8 | 80 | static void __exit ebt_snat_fini(void) |
| 1da177e4 | 81 | { |
| 043ef46c | 82 | xt_unregister_target(&ebt_snat_tg_reg); |
| 1da177e4 LT |
83 | } |
| 84 | ||
| 65b4b4e8 AM |
85 | module_init(ebt_snat_init); |
| 86 | module_exit(ebt_snat_fini); | |
| f776c4cd | 87 | MODULE_DESCRIPTION("Ebtables: Source MAC address translation"); |
| 1da177e4 | 88 | MODULE_LICENSE("GPL"); |