5 * Bart De Schuymer <bdschuym@pandora.be>
6 * Stephen Hemminger <shemminger@osdl.org>
11 #include <linux/netfilter_bridge/ebtables.h>
12 #include <linux/netfilter_bridge/ebt_stp.h>
13 #include <linux/module.h>
15 #define BPDU_TYPE_CONFIG 0
16 #define BPDU_TYPE_TCN 0x80
27 struct stp_config_pdu {
35 uint8_t hello_time[2];
36 uint8_t forward_delay[2];
39 #define NR16(p) (p[0] << 8 | p[1])
40 #define NR32(p) ((p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3])
42 static int ebt_filter_config(struct ebt_stp_info *info,
43 struct stp_config_pdu *stpc)
45 struct ebt_stp_config_info *c;
51 if ((info->bitmask & EBT_STP_FLAGS) &&
52 FWINV(c->flags != stpc->flags, EBT_STP_FLAGS))
54 if (info->bitmask & EBT_STP_ROOTPRIO) {
55 v16 = NR16(stpc->root);
56 if (FWINV(v16 < c->root_priol ||
57 v16 > c->root_priou, EBT_STP_ROOTPRIO))
60 if (info->bitmask & EBT_STP_ROOTADDR) {
62 for (i = 0; i < 6; i++)
63 verdict |= (stpc->root[2+i] ^ c->root_addr[i]) &
65 if (FWINV(verdict != 0, EBT_STP_ROOTADDR))
68 if (info->bitmask & EBT_STP_ROOTCOST) {
69 v32 = NR32(stpc->root_cost);
70 if (FWINV(v32 < c->root_costl ||
71 v32 > c->root_costu, EBT_STP_ROOTCOST))
74 if (info->bitmask & EBT_STP_SENDERPRIO) {
75 v16 = NR16(stpc->sender);
76 if (FWINV(v16 < c->sender_priol ||
77 v16 > c->sender_priou, EBT_STP_SENDERPRIO))
80 if (info->bitmask & EBT_STP_SENDERADDR) {
82 for (i = 0; i < 6; i++)
83 verdict |= (stpc->sender[2+i] ^ c->sender_addr[i]) &
85 if (FWINV(verdict != 0, EBT_STP_SENDERADDR))
88 if (info->bitmask & EBT_STP_PORT) {
89 v16 = NR16(stpc->port);
90 if (FWINV(v16 < c->portl ||
91 v16 > c->portu, EBT_STP_PORT))
94 if (info->bitmask & EBT_STP_MSGAGE) {
95 v16 = NR16(stpc->msg_age);
96 if (FWINV(v16 < c->msg_agel ||
97 v16 > c->msg_ageu, EBT_STP_MSGAGE))
100 if (info->bitmask & EBT_STP_MAXAGE) {
101 v16 = NR16(stpc->max_age);
102 if (FWINV(v16 < c->max_agel ||
103 v16 > c->max_ageu, EBT_STP_MAXAGE))
106 if (info->bitmask & EBT_STP_HELLOTIME) {
107 v16 = NR16(stpc->hello_time);
108 if (FWINV(v16 < c->hello_timel ||
109 v16 > c->hello_timeu, EBT_STP_HELLOTIME))
112 if (info->bitmask & EBT_STP_FWDD) {
113 v16 = NR16(stpc->forward_delay);
114 if (FWINV(v16 < c->forward_delayl ||
115 v16 > c->forward_delayu, EBT_STP_FWDD))
121 static int ebt_filter_stp(const struct sk_buff *skb, const struct net_device *in,
122 const struct net_device *out, const void *data, unsigned int datalen)
124 struct ebt_stp_info *info = (struct ebt_stp_info *)data;
125 struct stp_header _stph, *sp;
126 uint8_t header[6] = {0x42, 0x42, 0x03, 0x00, 0x00, 0x00};
128 sp = skb_header_pointer(skb, 0, sizeof(_stph), &_stph);
132 /* The stp code only considers these */
133 if (memcmp(sp, header, sizeof(header)))
136 if (info->bitmask & EBT_STP_TYPE
137 && FWINV(info->type != sp->type, EBT_STP_TYPE))
140 if (sp->type == BPDU_TYPE_CONFIG &&
141 info->bitmask & EBT_STP_CONFIG_MASK) {
142 struct stp_config_pdu _stpc, *st;
144 st = skb_header_pointer(skb, sizeof(_stph),
145 sizeof(_stpc), &_stpc);
148 return ebt_filter_config(info, st);
153 static int ebt_stp_check(const char *tablename, unsigned int hookmask,
154 const struct ebt_entry *e, void *data, unsigned int datalen)
156 struct ebt_stp_info *info = (struct ebt_stp_info *)data;
157 int len = EBT_ALIGN(sizeof(struct ebt_stp_info));
158 uint8_t bridge_ula[6] = { 0x01, 0x80, 0xc2, 0x00, 0x00, 0x00 };
159 uint8_t msk[6] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
161 if (info->bitmask & ~EBT_STP_MASK || info->invflags & ~EBT_STP_MASK ||
162 !(info->bitmask & EBT_STP_MASK))
166 /* Make sure the match only receives stp frames */
167 if (compare_ether_addr(e->destmac, bridge_ula) ||
168 compare_ether_addr(e->destmsk, msk) || !(e->bitmask & EBT_DESTMAC))
174 static struct ebt_match filter_stp =
176 .name = EBT_STP_MATCH,
177 .match = ebt_filter_stp,
178 .check = ebt_stp_check,
182 static int __init init(void)
184 return ebt_register_match(&filter_stp);
187 static void __exit fini(void)
189 ebt_unregister_match(&filter_stp);
194 MODULE_LICENSE("GPL");