projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 1da177e4 LT |
1 | /* |
| 2 | * ebt_arpreply | |
| 3 | * | |
| 4 | * Authors: | |
| 5 | * Grzegorz Borowiak <grzes@gnu.univ.gda.pl> | |
| 6 | * Bart De Schuymer <bdschuym@pandora.be> | |
| 7 | * | |
| 8 | * August, 2003 | |
| 9 | * | |
| 10 | */ | |
| 11 | ||
| 12 | #include <linux/netfilter_bridge/ebtables.h> | |
| 13 | #include <linux/netfilter_bridge/ebt_arpreply.h> | |
| 14 | #include <linux/if_arp.h> | |
| 15 | #include <net/arp.h> | |
| 16 | #include <linux/module.h> | |
| 17 | ||
| 18 | static int ebt_target_reply(struct sk_buff **pskb, unsigned int hooknr, | |
| 19 | const struct net_device *in, const struct net_device *out, | |
| 20 | const void *data, unsigned int datalen) | |
| 21 | { | |
| 22 | struct ebt_arpreply_info *info = (struct ebt_arpreply_info *)data; | |
| ed9bad06 | 23 | __be32 _sip, *siptr, _dip, *diptr; |
| 1da177e4 LT |
24 | struct arphdr _ah, *ap; |
| 25 | unsigned char _sha[ETH_ALEN], *shp; | |
| 26 | struct sk_buff *skb = *pskb; | |
| 27 | ||
| 28 | ap = skb_header_pointer(skb, 0, sizeof(_ah), &_ah); | |
| 29 | if (ap == NULL) | |
| 30 | return EBT_DROP; | |
| 31 | ||
| 32 | if (ap->ar_op != htons(ARPOP_REQUEST) || | |
| 33 | ap->ar_hln != ETH_ALEN || | |
| 34 | ap->ar_pro != htons(ETH_P_IP) || | |
| 35 | ap->ar_pln != 4) | |
| 36 | return EBT_CONTINUE; | |
| 37 | ||
| 38 | shp = skb_header_pointer(skb, sizeof(_ah), ETH_ALEN, &_sha); | |
| 39 | if (shp == NULL) | |
| 40 | return EBT_DROP; | |
| 41 | ||
| 42 | siptr = skb_header_pointer(skb, sizeof(_ah) + ETH_ALEN, | |
| 43 | sizeof(_sip), &_sip); | |
| 44 | if (siptr == NULL) | |
| 45 | return EBT_DROP; | |
| 46 | ||
| 47 | diptr = skb_header_pointer(skb, | |
| 48 | sizeof(_ah) + 2 * ETH_ALEN + sizeof(_sip), | |
| 49 | sizeof(_dip), &_dip); | |
| 50 | if (diptr == NULL) | |
| 51 | return EBT_DROP; | |
| 52 | ||
| 53 | arp_send(ARPOP_REPLY, ETH_P_ARP, *siptr, (struct net_device *)in, | |
| 9d6f229f | 54 | *diptr, shp, info->mac, shp); |
| 1da177e4 LT |
55 | |
| 56 | return info->target; | |
| 57 | } | |
| 58 | ||
| 59 | static int ebt_target_reply_check(const char *tablename, unsigned int hookmask, | |
| 60 | const struct ebt_entry *e, void *data, unsigned int datalen) | |
| 61 | { | |
| 62 | struct ebt_arpreply_info *info = (struct ebt_arpreply_info *)data; | |
| 63 | ||
| 64 | if (datalen != EBT_ALIGN(sizeof(struct ebt_arpreply_info))) | |
| 65 | return -EINVAL; | |
| 66 | if (BASE_CHAIN && info->target == EBT_RETURN) | |
| 67 | return -EINVAL; | |
| 68 | if (e->ethproto != htons(ETH_P_ARP) || | |
| 69 | e->invflags & EBT_IPROTO) | |
| 70 | return -EINVAL; | |
| 71 | CLEAR_BASE_CHAIN_BIT; | |
| 72 | if (strcmp(tablename, "nat") || hookmask & ~(1 << NF_BR_PRE_ROUTING)) | |
| 73 | return -EINVAL; | |
| 74 | return 0; | |
| 75 | } | |
| 76 | ||
| 77 | static struct ebt_target reply_target = | |
| 78 | { | |
| 79 | .name = EBT_ARPREPLY_TARGET, | |
| 80 | .target = ebt_target_reply, | |
| 81 | .check = ebt_target_reply_check, | |
| 82 | .me = THIS_MODULE, | |
| 83 | }; | |
| 84 | ||
| 65b4b4e8 | 85 | static int __init ebt_arpreply_init(void) |
| 1da177e4 LT |
86 | { |
| 87 | return ebt_register_target(&reply_target); | |
| 88 | } | |
| 89 | ||
| 65b4b4e8 | 90 | static void __exit ebt_arpreply_fini(void) |
| 1da177e4 LT |
91 | { |
| 92 | ebt_unregister_target(&reply_target); | |
| 93 | } | |
| 94 | ||
| 65b4b4e8 AM |
95 | module_init(ebt_arpreply_init); |
| 96 | module_exit(ebt_arpreply_fini); | |
| 1da177e4 | 97 | MODULE_LICENSE("GPL"); |