Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * ebt_arp | |
3 | * | |
4 | * Authors: | |
5 | * Bart De Schuymer <bdschuym@pandora.be> | |
6 | * Tim Gardner <timg@tpi.com> | |
7 | * | |
8 | * April, 2002 | |
9 | * | |
10 | */ | |
1da177e4 LT |
11 | #include <linux/if_arp.h> |
12 | #include <linux/if_ether.h> | |
13 | #include <linux/module.h> | |
18219d3f JE |
14 | #include <linux/netfilter/x_tables.h> |
15 | #include <linux/netfilter_bridge/ebtables.h> | |
16 | #include <linux/netfilter_bridge/ebt_arp.h> | |
1da177e4 | 17 | |
2d06d4a5 | 18 | static bool |
62fc8051 | 19 | ebt_arp_mt(const struct sk_buff *skb, struct xt_action_param *par) |
1da177e4 | 20 | { |
f7108a20 | 21 | const struct ebt_arp_info *info = par->matchinfo; |
abfdf1c4 JE |
22 | const struct arphdr *ah; |
23 | struct arphdr _arph; | |
1da177e4 LT |
24 | |
25 | ah = skb_header_pointer(skb, 0, sizeof(_arph), &_arph); | |
26 | if (ah == NULL) | |
8cc784ee | 27 | return false; |
c37a2dfa JP |
28 | if ((info->bitmask & EBT_ARP_OPCODE) && |
29 | NF_INVF(info, EBT_ARP_OPCODE, info->opcode != ah->ar_op)) | |
8cc784ee | 30 | return false; |
c37a2dfa JP |
31 | if ((info->bitmask & EBT_ARP_HTYPE) && |
32 | NF_INVF(info, EBT_ARP_HTYPE, info->htype != ah->ar_hrd)) | |
8cc784ee | 33 | return false; |
c37a2dfa JP |
34 | if ((info->bitmask & EBT_ARP_PTYPE) && |
35 | NF_INVF(info, EBT_ARP_PTYPE, info->ptype != ah->ar_pro)) | |
8cc784ee | 36 | return false; |
1da177e4 | 37 | |
e011ff48 | 38 | if (info->bitmask & (EBT_ARP_SRC_IP | EBT_ARP_DST_IP | EBT_ARP_GRAT)) { |
abfdf1c4 JE |
39 | const __be32 *sap, *dap; |
40 | __be32 saddr, daddr; | |
1da177e4 | 41 | |
c15bf6e6 | 42 | if (ah->ar_pln != sizeof(__be32) || ah->ar_pro != htons(ETH_P_IP)) |
8cc784ee | 43 | return false; |
c15bf6e6 BDS |
44 | sap = skb_header_pointer(skb, sizeof(struct arphdr) + |
45 | ah->ar_hln, sizeof(saddr), | |
46 | &saddr); | |
47 | if (sap == NULL) | |
8cc784ee | 48 | return false; |
c15bf6e6 BDS |
49 | dap = skb_header_pointer(skb, sizeof(struct arphdr) + |
50 | 2*ah->ar_hln+sizeof(saddr), | |
51 | sizeof(daddr), &daddr); | |
52 | if (dap == NULL) | |
8cc784ee | 53 | return false; |
c37a2dfa JP |
54 | if ((info->bitmask & EBT_ARP_SRC_IP) && |
55 | NF_INVF(info, EBT_ARP_SRC_IP, | |
56 | info->saddr != (*sap & info->smsk))) | |
8cc784ee | 57 | return false; |
c37a2dfa JP |
58 | if ((info->bitmask & EBT_ARP_DST_IP) && |
59 | NF_INVF(info, EBT_ARP_DST_IP, | |
60 | info->daddr != (*dap & info->dmsk))) | |
8cc784ee | 61 | return false; |
c37a2dfa JP |
62 | if ((info->bitmask & EBT_ARP_GRAT) && |
63 | NF_INVF(info, EBT_ARP_GRAT, *dap != *sap)) | |
8cc784ee | 64 | return false; |
1da177e4 LT |
65 | } |
66 | ||
67 | if (info->bitmask & (EBT_ARP_SRC_MAC | EBT_ARP_DST_MAC)) { | |
abfdf1c4 JE |
68 | const unsigned char *mp; |
69 | unsigned char _mac[ETH_ALEN]; | |
1da177e4 | 70 | |
c15bf6e6 | 71 | if (ah->ar_hln != ETH_ALEN || ah->ar_hrd != htons(ARPHRD_ETHER)) |
8cc784ee | 72 | return false; |
1da177e4 LT |
73 | if (info->bitmask & EBT_ARP_SRC_MAC) { |
74 | mp = skb_header_pointer(skb, sizeof(struct arphdr), | |
75 | sizeof(_mac), &_mac); | |
76 | if (mp == NULL) | |
8cc784ee | 77 | return false; |
c37a2dfa JP |
78 | if (NF_INVF(info, EBT_ARP_SRC_MAC, |
79 | !ether_addr_equal_masked(mp, info->smaddr, | |
80 | info->smmsk))) | |
8cc784ee | 81 | return false; |
1da177e4 LT |
82 | } |
83 | ||
84 | if (info->bitmask & EBT_ARP_DST_MAC) { | |
85 | mp = skb_header_pointer(skb, sizeof(struct arphdr) + | |
86 | ah->ar_hln + ah->ar_pln, | |
87 | sizeof(_mac), &_mac); | |
88 | if (mp == NULL) | |
8cc784ee | 89 | return false; |
c37a2dfa JP |
90 | if (NF_INVF(info, EBT_ARP_DST_MAC, |
91 | !ether_addr_equal_masked(mp, info->dmaddr, | |
92 | info->dmmsk))) | |
8cc784ee | 93 | return false; |
1da177e4 LT |
94 | } |
95 | } | |
96 | ||
8cc784ee | 97 | return true; |
1da177e4 LT |
98 | } |
99 | ||
b0f38452 | 100 | static int ebt_arp_mt_check(const struct xt_mtchk_param *par) |
1da177e4 | 101 | { |
9b4fce7a JE |
102 | const struct ebt_arp_info *info = par->matchinfo; |
103 | const struct ebt_entry *e = par->entryinfo; | |
1da177e4 | 104 | |
1da177e4 LT |
105 | if ((e->ethproto != htons(ETH_P_ARP) && |
106 | e->ethproto != htons(ETH_P_RARP)) || | |
107 | e->invflags & EBT_IPROTO) | |
bd414ee6 | 108 | return -EINVAL; |
1da177e4 | 109 | if (info->bitmask & ~EBT_ARP_MASK || info->invflags & ~EBT_ARP_MASK) |
bd414ee6 JE |
110 | return -EINVAL; |
111 | return 0; | |
1da177e4 LT |
112 | } |
113 | ||
043ef46c JE |
114 | static struct xt_match ebt_arp_mt_reg __read_mostly = { |
115 | .name = "arp", | |
001a18d3 JE |
116 | .revision = 0, |
117 | .family = NFPROTO_BRIDGE, | |
2d06d4a5 JE |
118 | .match = ebt_arp_mt, |
119 | .checkentry = ebt_arp_mt_check, | |
fc0e3df4 | 120 | .matchsize = sizeof(struct ebt_arp_info), |
1da177e4 LT |
121 | .me = THIS_MODULE, |
122 | }; | |
123 | ||
65b4b4e8 | 124 | static int __init ebt_arp_init(void) |
1da177e4 | 125 | { |
043ef46c | 126 | return xt_register_match(&ebt_arp_mt_reg); |
1da177e4 LT |
127 | } |
128 | ||
65b4b4e8 | 129 | static void __exit ebt_arp_fini(void) |
1da177e4 | 130 | { |
043ef46c | 131 | xt_unregister_match(&ebt_arp_mt_reg); |
1da177e4 LT |
132 | } |
133 | ||
65b4b4e8 AM |
134 | module_init(ebt_arp_init); |
135 | module_exit(ebt_arp_fini); | |
f776c4cd | 136 | MODULE_DESCRIPTION("Ebtables: ARP protocol packet match"); |
1da177e4 | 137 | MODULE_LICENSE("GPL"); |