Commit | Line | Data |
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09c434b8 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
1da177e4 LT |
2 | /* |
3 | * ebt_stp | |
4 | * | |
5 | * Authors: | |
6 | * Bart De Schuymer <bdschuym@pandora.be> | |
7 | * Stephen Hemminger <shemminger@osdl.org> | |
8 | * | |
9 | * July, 2003 | |
10 | */ | |
82bf7e97 | 11 | #include <linux/etherdevice.h> |
1da177e4 | 12 | #include <linux/module.h> |
18219d3f JE |
13 | #include <linux/netfilter/x_tables.h> |
14 | #include <linux/netfilter_bridge/ebtables.h> | |
15 | #include <linux/netfilter_bridge/ebt_stp.h> | |
1da177e4 LT |
16 | |
17 | #define BPDU_TYPE_CONFIG 0 | |
18 | #define BPDU_TYPE_TCN 0x80 | |
19 | ||
20 | struct stp_header { | |
402f9030 TH |
21 | u8 dsap; |
22 | u8 ssap; | |
23 | u8 ctrl; | |
24 | u8 pid; | |
25 | u8 vers; | |
26 | u8 type; | |
1da177e4 LT |
27 | }; |
28 | ||
29 | struct stp_config_pdu { | |
402f9030 TH |
30 | u8 flags; |
31 | u8 root[8]; | |
32 | u8 root_cost[4]; | |
33 | u8 sender[8]; | |
34 | u8 port[2]; | |
35 | u8 msg_age[2]; | |
36 | u8 max_age[2]; | |
37 | u8 hello_time[2]; | |
38 | u8 forward_delay[2]; | |
1da177e4 LT |
39 | }; |
40 | ||
41 | #define NR16(p) (p[0] << 8 | p[1]) | |
42 | #define NR32(p) ((p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3]) | |
43 | ||
8cc784ee | 44 | static bool ebt_filter_config(const struct ebt_stp_info *info, |
052a4bc4 | 45 | const struct stp_config_pdu *stpc) |
1da177e4 | 46 | { |
abfdf1c4 | 47 | const struct ebt_stp_config_info *c; |
402f9030 TH |
48 | u16 v16; |
49 | u32 v32; | |
1da177e4 LT |
50 | |
51 | c = &info->config; | |
52 | if ((info->bitmask & EBT_STP_FLAGS) && | |
c37a2dfa | 53 | NF_INVF(info, EBT_STP_FLAGS, c->flags != stpc->flags)) |
8cc784ee | 54 | return false; |
1da177e4 LT |
55 | if (info->bitmask & EBT_STP_ROOTPRIO) { |
56 | v16 = NR16(stpc->root); | |
c37a2dfa JP |
57 | if (NF_INVF(info, EBT_STP_ROOTPRIO, |
58 | v16 < c->root_priol || v16 > c->root_priou)) | |
8cc784ee | 59 | return false; |
1da177e4 LT |
60 | } |
61 | if (info->bitmask & EBT_STP_ROOTADDR) { | |
c37a2dfa JP |
62 | if (NF_INVF(info, EBT_STP_ROOTADDR, |
63 | !ether_addr_equal_masked(&stpc->root[2], | |
64 | c->root_addr, | |
65 | c->root_addrmsk))) | |
8cc784ee | 66 | return false; |
1da177e4 LT |
67 | } |
68 | if (info->bitmask & EBT_STP_ROOTCOST) { | |
69 | v32 = NR32(stpc->root_cost); | |
c37a2dfa JP |
70 | if (NF_INVF(info, EBT_STP_ROOTCOST, |
71 | v32 < c->root_costl || v32 > c->root_costu)) | |
8cc784ee | 72 | return false; |
1da177e4 LT |
73 | } |
74 | if (info->bitmask & EBT_STP_SENDERPRIO) { | |
75 | v16 = NR16(stpc->sender); | |
c37a2dfa JP |
76 | if (NF_INVF(info, EBT_STP_SENDERPRIO, |
77 | v16 < c->sender_priol || v16 > c->sender_priou)) | |
8cc784ee | 78 | return false; |
1da177e4 LT |
79 | } |
80 | if (info->bitmask & EBT_STP_SENDERADDR) { | |
c37a2dfa JP |
81 | if (NF_INVF(info, EBT_STP_SENDERADDR, |
82 | !ether_addr_equal_masked(&stpc->sender[2], | |
83 | c->sender_addr, | |
84 | c->sender_addrmsk))) | |
8cc784ee | 85 | return false; |
1da177e4 LT |
86 | } |
87 | if (info->bitmask & EBT_STP_PORT) { | |
88 | v16 = NR16(stpc->port); | |
c37a2dfa JP |
89 | if (NF_INVF(info, EBT_STP_PORT, |
90 | v16 < c->portl || v16 > c->portu)) | |
8cc784ee | 91 | return false; |
1da177e4 LT |
92 | } |
93 | if (info->bitmask & EBT_STP_MSGAGE) { | |
94 | v16 = NR16(stpc->msg_age); | |
c37a2dfa JP |
95 | if (NF_INVF(info, EBT_STP_MSGAGE, |
96 | v16 < c->msg_agel || v16 > c->msg_ageu)) | |
8cc784ee | 97 | return false; |
1da177e4 LT |
98 | } |
99 | if (info->bitmask & EBT_STP_MAXAGE) { | |
100 | v16 = NR16(stpc->max_age); | |
c37a2dfa JP |
101 | if (NF_INVF(info, EBT_STP_MAXAGE, |
102 | v16 < c->max_agel || v16 > c->max_ageu)) | |
8cc784ee | 103 | return false; |
1da177e4 LT |
104 | } |
105 | if (info->bitmask & EBT_STP_HELLOTIME) { | |
106 | v16 = NR16(stpc->hello_time); | |
c37a2dfa JP |
107 | if (NF_INVF(info, EBT_STP_HELLOTIME, |
108 | v16 < c->hello_timel || v16 > c->hello_timeu)) | |
8cc784ee | 109 | return false; |
1da177e4 LT |
110 | } |
111 | if (info->bitmask & EBT_STP_FWDD) { | |
112 | v16 = NR16(stpc->forward_delay); | |
c37a2dfa JP |
113 | if (NF_INVF(info, EBT_STP_FWDD, |
114 | v16 < c->forward_delayl || v16 > c->forward_delayu)) | |
8cc784ee | 115 | return false; |
1da177e4 | 116 | } |
8cc784ee | 117 | return true; |
1da177e4 LT |
118 | } |
119 | ||
2d06d4a5 | 120 | static bool |
62fc8051 | 121 | ebt_stp_mt(const struct sk_buff *skb, struct xt_action_param *par) |
1da177e4 | 122 | { |
f7108a20 | 123 | const struct ebt_stp_info *info = par->matchinfo; |
abfdf1c4 JE |
124 | const struct stp_header *sp; |
125 | struct stp_header _stph; | |
402f9030 | 126 | const u8 header[6] = {0x42, 0x42, 0x03, 0x00, 0x00, 0x00}; |
1da177e4 LT |
127 | |
128 | sp = skb_header_pointer(skb, 0, sizeof(_stph), &_stph); | |
129 | if (sp == NULL) | |
8cc784ee | 130 | return false; |
1da177e4 LT |
131 | |
132 | /* The stp code only considers these */ | |
133 | if (memcmp(sp, header, sizeof(header))) | |
8cc784ee | 134 | return false; |
1da177e4 | 135 | |
c37a2dfa JP |
136 | if ((info->bitmask & EBT_STP_TYPE) && |
137 | NF_INVF(info, EBT_STP_TYPE, info->type != sp->type)) | |
8cc784ee | 138 | return false; |
1da177e4 LT |
139 | |
140 | if (sp->type == BPDU_TYPE_CONFIG && | |
141 | info->bitmask & EBT_STP_CONFIG_MASK) { | |
abfdf1c4 JE |
142 | const struct stp_config_pdu *st; |
143 | struct stp_config_pdu _stpc; | |
1da177e4 LT |
144 | |
145 | st = skb_header_pointer(skb, sizeof(_stph), | |
146 | sizeof(_stpc), &_stpc); | |
147 | if (st == NULL) | |
8cc784ee | 148 | return false; |
1da177e4 LT |
149 | return ebt_filter_config(info, st); |
150 | } | |
8cc784ee | 151 | return true; |
1da177e4 LT |
152 | } |
153 | ||
b0f38452 | 154 | static int ebt_stp_mt_check(const struct xt_mtchk_param *par) |
1da177e4 | 155 | { |
9b4fce7a | 156 | const struct ebt_stp_info *info = par->matchinfo; |
9b4fce7a | 157 | const struct ebt_entry *e = par->entryinfo; |
1da177e4 LT |
158 | |
159 | if (info->bitmask & ~EBT_STP_MASK || info->invflags & ~EBT_STP_MASK || | |
160 | !(info->bitmask & EBT_STP_MASK)) | |
bd414ee6 | 161 | return -EINVAL; |
1da177e4 | 162 | /* Make sure the match only receives stp frames */ |
55917a21 | 163 | if (!par->nft_compat && |
9124a20d | 164 | (!ether_addr_equal(e->destmac, eth_stp_addr) || |
a4995684 SH |
165 | !(e->bitmask & EBT_DESTMAC) || |
166 | !is_broadcast_ether_addr(e->destmsk))) | |
bd414ee6 | 167 | return -EINVAL; |
1da177e4 | 168 | |
bd414ee6 | 169 | return 0; |
1da177e4 LT |
170 | } |
171 | ||
043ef46c JE |
172 | static struct xt_match ebt_stp_mt_reg __read_mostly = { |
173 | .name = "stp", | |
001a18d3 JE |
174 | .revision = 0, |
175 | .family = NFPROTO_BRIDGE, | |
2d06d4a5 JE |
176 | .match = ebt_stp_mt, |
177 | .checkentry = ebt_stp_mt_check, | |
fc0e3df4 | 178 | .matchsize = sizeof(struct ebt_stp_info), |
1da177e4 LT |
179 | .me = THIS_MODULE, |
180 | }; | |
181 | ||
65b4b4e8 | 182 | static int __init ebt_stp_init(void) |
1da177e4 | 183 | { |
043ef46c | 184 | return xt_register_match(&ebt_stp_mt_reg); |
1da177e4 LT |
185 | } |
186 | ||
65b4b4e8 | 187 | static void __exit ebt_stp_fini(void) |
1da177e4 | 188 | { |
043ef46c | 189 | xt_unregister_match(&ebt_stp_mt_reg); |
1da177e4 LT |
190 | } |
191 | ||
65b4b4e8 AM |
192 | module_init(ebt_stp_init); |
193 | module_exit(ebt_stp_fini); | |
f776c4cd | 194 | MODULE_DESCRIPTION("Ebtables: Spanning Tree Protocol packet match"); |
1da177e4 | 195 | MODULE_LICENSE("GPL"); |