Bart De Schuymer | e5ed216 | 2002-09-16 20:02:51 +0000 | [diff] [blame] | 1 | /* |
| 2 | * ebt_arp |
| 3 | * |
| 4 | * Authors: |
Bart De Schuymer | 42a25de | 2003-03-01 12:24:14 +0000 | [diff] [blame] | 5 | * Bart De Schuymer <bdschuym@pandora.be> |
Bart De Schuymer | e5ed216 | 2002-09-16 20:02:51 +0000 | [diff] [blame] | 6 | * Tim Gardner <timg@tpi.com> |
| 7 | * |
| 8 | * April, 2002 |
| 9 | * |
| 10 | */ |
| 11 | |
| 12 | #include <linux/netfilter_bridge/ebtables.h> |
| 13 | #include <linux/netfilter_bridge/ebt_arp.h> |
| 14 | #include <linux/if_arp.h> |
Bart De Schuymer | 8f38647 | 2003-05-03 18:13:34 +0000 | [diff] [blame] | 15 | #include <linux/if_ether.h> |
Bart De Schuymer | 5ba7349 | 2003-06-01 17:14:02 +0000 | [diff] [blame] | 16 | #include <linux/module.h> |
Bart De Schuymer | e5ed216 | 2002-09-16 20:02:51 +0000 | [diff] [blame] | 17 | |
| 18 | static int ebt_filter_arp(const struct sk_buff *skb, const struct net_device *in, |
| 19 | const struct net_device *out, const void *data, unsigned int datalen) |
| 20 | { |
| 21 | struct ebt_arp_info *info = (struct ebt_arp_info *)data; |
Bart De Schuymer | 5ba7349 | 2003-06-01 17:14:02 +0000 | [diff] [blame] | 22 | struct arphdr arph; |
Bart De Schuymer | e5ed216 | 2002-09-16 20:02:51 +0000 | [diff] [blame] | 23 | |
Bart De Schuymer | 5ba7349 | 2003-06-01 17:14:02 +0000 | [diff] [blame] | 24 | if (skb_copy_bits(skb, 0, &arph, sizeof(arph))) |
| 25 | return EBT_NOMATCH; |
Bart De Schuymer | e5ed216 | 2002-09-16 20:02:51 +0000 | [diff] [blame] | 26 | if (info->bitmask & EBT_ARP_OPCODE && FWINV(info->opcode != |
Bart De Schuymer | 5ba7349 | 2003-06-01 17:14:02 +0000 | [diff] [blame] | 27 | arph.ar_op, EBT_ARP_OPCODE)) |
Bart De Schuymer | e5ed216 | 2002-09-16 20:02:51 +0000 | [diff] [blame] | 28 | return EBT_NOMATCH; |
| 29 | if (info->bitmask & EBT_ARP_HTYPE && FWINV(info->htype != |
Bart De Schuymer | 5ba7349 | 2003-06-01 17:14:02 +0000 | [diff] [blame] | 30 | arph.ar_hrd, EBT_ARP_HTYPE)) |
Bart De Schuymer | e5ed216 | 2002-09-16 20:02:51 +0000 | [diff] [blame] | 31 | return EBT_NOMATCH; |
| 32 | if (info->bitmask & EBT_ARP_PTYPE && FWINV(info->ptype != |
Bart De Schuymer | 5ba7349 | 2003-06-01 17:14:02 +0000 | [diff] [blame] | 33 | arph.ar_pro, EBT_ARP_PTYPE)) |
Bart De Schuymer | e5ed216 | 2002-09-16 20:02:51 +0000 | [diff] [blame] | 34 | return EBT_NOMATCH; |
| 35 | |
Bart De Schuymer | 5ba7349 | 2003-06-01 17:14:02 +0000 | [diff] [blame] | 36 | if (info->bitmask & (EBT_ARP_SRC_IP | EBT_ARP_DST_IP)) { |
| 37 | uint32_t addr; |
Bart De Schuymer | e5ed216 | 2002-09-16 20:02:51 +0000 | [diff] [blame] | 38 | |
Bart De Schuymer | 8ed17d1 | 2003-03-02 15:18:08 +0000 | [diff] [blame] | 39 | /* IPv4 addresses are always 4 bytes */ |
Bart De Schuymer | 5ba7349 | 2003-06-01 17:14:02 +0000 | [diff] [blame] | 40 | if (arph.ar_pln != sizeof(uint32_t)) |
Bart De Schuymer | e5ed216 | 2002-09-16 20:02:51 +0000 | [diff] [blame] | 41 | return EBT_NOMATCH; |
Bart De Schuymer | e5ed216 | 2002-09-16 20:02:51 +0000 | [diff] [blame] | 42 | if (info->bitmask & EBT_ARP_SRC_IP) { |
Bart De Schuymer | 5ba7349 | 2003-06-01 17:14:02 +0000 | [diff] [blame] | 43 | if (skb_copy_bits(skb, sizeof(struct arphdr) + |
| 44 | arph.ar_hln, &addr, sizeof(addr))) |
| 45 | return EBT_NOMATCH; |
| 46 | if (FWINV(info->saddr != (addr & info->smsk), |
Bart De Schuymer | e5ed216 | 2002-09-16 20:02:51 +0000 | [diff] [blame] | 47 | EBT_ARP_SRC_IP)) |
| 48 | return EBT_NOMATCH; |
| 49 | } |
| 50 | |
| 51 | if (info->bitmask & EBT_ARP_DST_IP) { |
Bart De Schuymer | 5ba7349 | 2003-06-01 17:14:02 +0000 | [diff] [blame] | 52 | if (skb_copy_bits(skb, sizeof(struct arphdr) + |
| 53 | 2*arph.ar_hln + sizeof(uint32_t), &addr, |
| 54 | sizeof(addr))) |
| 55 | return EBT_NOMATCH; |
| 56 | if (FWINV(info->daddr != (addr & info->dmsk), |
Bart De Schuymer | e5ed216 | 2002-09-16 20:02:51 +0000 | [diff] [blame] | 57 | EBT_ARP_DST_IP)) |
| 58 | return EBT_NOMATCH; |
| 59 | } |
| 60 | } |
Bart De Schuymer | 8f38647 | 2003-05-03 18:13:34 +0000 | [diff] [blame] | 61 | |
Bart De Schuymer | 5ba7349 | 2003-06-01 17:14:02 +0000 | [diff] [blame] | 62 | if (info->bitmask & (EBT_ARP_SRC_MAC | EBT_ARP_DST_MAC)) { |
| 63 | unsigned char mac[ETH_ALEN]; |
| 64 | uint8_t verdict, i; |
Bart De Schuymer | 8f38647 | 2003-05-03 18:13:34 +0000 | [diff] [blame] | 65 | |
Bart De Schuymer | 8f38647 | 2003-05-03 18:13:34 +0000 | [diff] [blame] | 66 | /* MAC addresses are 6 bytes */ |
Bart De Schuymer | 5ba7349 | 2003-06-01 17:14:02 +0000 | [diff] [blame] | 67 | if (arph.ar_hln != ETH_ALEN) |
Bart De Schuymer | 8f38647 | 2003-05-03 18:13:34 +0000 | [diff] [blame] | 68 | return EBT_NOMATCH; |
| 69 | if (info->bitmask & EBT_ARP_SRC_MAC) { |
Bart De Schuymer | 5ba7349 | 2003-06-01 17:14:02 +0000 | [diff] [blame] | 70 | if (skb_copy_bits(skb, sizeof(struct arphdr), &mac, |
| 71 | ETH_ALEN)) |
| 72 | return EBT_NOMATCH; |
Bart De Schuymer | 8f38647 | 2003-05-03 18:13:34 +0000 | [diff] [blame] | 73 | verdict = 0; |
| 74 | for (i = 0; i < 6; i++) |
Bart De Schuymer | 5ba7349 | 2003-06-01 17:14:02 +0000 | [diff] [blame] | 75 | verdict |= (mac[i] ^ info->smaddr[i]) & |
Bart De Schuymer | 8f38647 | 2003-05-03 18:13:34 +0000 | [diff] [blame] | 76 | info->smmsk[i]; |
| 77 | if (FWINV(verdict != 0, EBT_ARP_SRC_MAC)) |
| 78 | return EBT_NOMATCH; |
| 79 | } |
| 80 | |
| 81 | if (info->bitmask & EBT_ARP_DST_MAC) { |
Bart De Schuymer | 5ba7349 | 2003-06-01 17:14:02 +0000 | [diff] [blame] | 82 | if (skb_copy_bits(skb, sizeof(struct arphdr) + |
| 83 | arph.ar_hln + arph.ar_pln, &mac, ETH_ALEN)) |
| 84 | return EBT_NOMATCH; |
Bart De Schuymer | 8f38647 | 2003-05-03 18:13:34 +0000 | [diff] [blame] | 85 | verdict = 0; |
| 86 | for (i = 0; i < 6; i++) |
Bart De Schuymer | 5ba7349 | 2003-06-01 17:14:02 +0000 | [diff] [blame] | 87 | verdict |= (mac[i] ^ info->dmaddr[i]) & |
Bart De Schuymer | 8f38647 | 2003-05-03 18:13:34 +0000 | [diff] [blame] | 88 | info->dmmsk[i]; |
| 89 | if (FWINV(verdict != 0, EBT_ARP_DST_MAC)) |
| 90 | return EBT_NOMATCH; |
| 91 | } |
| 92 | } |
| 93 | |
Bart De Schuymer | e5ed216 | 2002-09-16 20:02:51 +0000 | [diff] [blame] | 94 | return EBT_MATCH; |
| 95 | } |
| 96 | |
Bart De Schuymer | ff87172 | 2003-06-03 18:47:33 +0000 | [diff] [blame^] | 97 | static struct ebt_match filter_arp; |
Bart De Schuymer | e5ed216 | 2002-09-16 20:02:51 +0000 | [diff] [blame] | 98 | static int ebt_arp_check(const char *tablename, unsigned int hookmask, |
Bart De Schuymer | ff87172 | 2003-06-03 18:47:33 +0000 | [diff] [blame^] | 99 | const struct ebt_entry *e, void *data, unsigned int datalen, |
| 100 | unsigned int version) |
Bart De Schuymer | e5ed216 | 2002-09-16 20:02:51 +0000 | [diff] [blame] | 101 | { |
| 102 | struct ebt_arp_info *info = (struct ebt_arp_info *)data; |
| 103 | |
| 104 | if (datalen != sizeof(struct ebt_arp_info)) |
| 105 | return -EINVAL; |
Bart De Schuymer | ff87172 | 2003-06-03 18:47:33 +0000 | [diff] [blame^] | 106 | if (ebt_check_version(version, filter_arp.version, filter_arp.name)) |
| 107 | return -EINVAL; |
Bart De Schuymer | e5ed216 | 2002-09-16 20:02:51 +0000 | [diff] [blame] | 108 | if ((e->ethproto != __constant_htons(ETH_P_ARP) && |
| 109 | e->ethproto != __constant_htons(ETH_P_RARP)) || |
| 110 | e->invflags & EBT_IPROTO) |
| 111 | return -EINVAL; |
| 112 | if (info->bitmask & ~EBT_ARP_MASK || info->invflags & ~EBT_ARP_MASK) |
| 113 | return -EINVAL; |
| 114 | return 0; |
| 115 | } |
| 116 | |
| 117 | static struct ebt_match filter_arp = |
| 118 | { |
Bart De Schuymer | 8ed17d1 | 2003-03-02 15:18:08 +0000 | [diff] [blame] | 119 | .name = EBT_ARP_MATCH, |
| 120 | .match = ebt_filter_arp, |
| 121 | .check = ebt_arp_check, |
Bart De Schuymer | 02fd595 | 2003-03-03 13:01:37 +0000 | [diff] [blame] | 122 | .me = THIS_MODULE, |
Bart De Schuymer | ff87172 | 2003-06-03 18:47:33 +0000 | [diff] [blame^] | 123 | .version = VERSIONIZE(1,0), |
Bart De Schuymer | e5ed216 | 2002-09-16 20:02:51 +0000 | [diff] [blame] | 124 | }; |
| 125 | |
| 126 | static int __init init(void) |
| 127 | { |
| 128 | return ebt_register_match(&filter_arp); |
| 129 | } |
| 130 | |
| 131 | static void __exit fini(void) |
| 132 | { |
| 133 | ebt_unregister_match(&filter_arp); |
| 134 | } |
| 135 | |
| 136 | module_init(init); |
| 137 | module_exit(fini); |
| 138 | MODULE_LICENSE("GPL"); |