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List: linux-bridge
Subject: [PATCH] [BRIDGE] Add stp packet matching
From: Bart De Schuymer <bdschuym () pandora ! be>
Date: 2003-07-18 6:34:55
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H Dave,
The patch below adds the ebtables stp packet matching module.
cheers,
Bart
--- linux-2.6.0-test1/net/bridge/netfilter/Makefile.old Tue Jul 15 20:56:27 2003
+++ linux-2.6.0-test1/net/bridge/netfilter/Makefile Tue Jul 15 20:57:39 2003
@@ -11,6 +11,7 @@ obj-$(CONFIG_BRIDGE_EBT_ARP) += ebt_arp.
obj-$(CONFIG_BRIDGE_EBT_VLAN) += ebt_vlan.o
obj-$(CONFIG_BRIDGE_EBT_MARK) += ebt_mark_m.o
obj-$(CONFIG_BRIDGE_EBT_PKTTYPE) += ebt_pkttype.o
+obj-$(CONFIG_BRIDGE_EBT_STP) += ebt_stp.o
obj-$(CONFIG_BRIDGE_EBT_LOG) += ebt_log.o
obj-$(CONFIG_BRIDGE_EBT_SNAT) += ebt_snat.o
obj-$(CONFIG_BRIDGE_EBT_DNAT) += ebt_dnat.o
--- linux-2.6.0-test1/net/bridge/netfilter/Kconfig.old Tue Jul 15 20:56:23 2003
+++ linux-2.6.0-test1/net/bridge/netfilter/Kconfig Tue Jul 15 20:59:00 2003
@@ -103,6 +103,16 @@ config BRIDGE_EBT_PKTTYPE
If you want to compile it as a module, say M here and read
<file:Documentation/modules.txt>. If unsure, say `N'.
+config BRIDGE_EBT_STP
+ tristate "ebt: STP filter support"
+ depends on BRIDGE_NF_EBTABLES
+ help
+ This option adds the Spanning Tree Protocol match, which
+ allows STP header field filtering.
+
+ If you want to compile it as a module, say M here and read
+ <file:Documentation/modules.txt>. If unsure, say `N'.
+
config BRIDGE_EBT_SNAT
tristate "ebt: snat target support"
depends on BRIDGE_NF_EBTABLES
--- /dev/null Thu Aug 24 11:00:32 2000
+++ linux-2.6.0-test1/net/bridge/netfilter/ebt_stp.c Thu Jul 17 23:40:42 2003
@@ -0,0 +1,190 @@
+/*
+ * ebt_stp
+ *
+ * Authors:
+ * Bart De Schuymer <bdschuym@pandora.be>
+ * Stephen Hemminger <shemminger@osdl.org>
+ *
+ * July, 2003
+ */
+
+#include <linux/netfilter_bridge/ebtables.h>
+#include <linux/netfilter_bridge/ebt_stp.h>
+#include <linux/module.h>
+
+#define BPDU_TYPE_CONFIG 0
+#define BPDU_TYPE_TCN 0x80
+
+struct stp_header {
+ uint8_t dsap;
+ uint8_t ssap;
+ uint8_t ctrl;
+ uint8_t pid;
+ uint8_t vers;
+ uint8_t type;
+};
+
+struct stp_config_pdu {
+ uint8_t flags;
+ uint8_t root[8];
+ uint8_t root_cost[4];
+ uint8_t sender[8];
+ uint8_t port[2];
+ uint8_t msg_age[2];
+ uint8_t max_age[2];
+ uint8_t hello_time[2];
+ uint8_t forward_delay[2];
+};
+
+#define NR16(p) (p[0] << 8 | p[1])
+#define NR32(p) ((p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3])
+
+static int ebt_filter_config(struct ebt_stp_info *info,
+ struct stp_config_pdu *stpc)
+{
+ struct ebt_stp_config_info *c;
+ uint16_t v16;
+ uint32_t v32;
+ int verdict, i;
+
+ c = &info->config;
+ if ((info->bitmask & EBT_STP_FLAGS) &&
+ FWINV(c->flags != stpc->flags, EBT_STP_FLAGS))
+ return EBT_NOMATCH;
+ if (info->bitmask & EBT_STP_ROOTPRIO) {
+ v16 = NR16(stpc->root);
+ if (FWINV(v16 < c->root_priol ||
+ v16 > c->root_priou, EBT_STP_ROOTPRIO))
+ return EBT_NOMATCH;
+ }
+ if (info->bitmask & EBT_STP_ROOTADDR) {
+ verdict = 0;
+ for (i = 0; i < 6; i++)
+ verdict |= (stpc->root[2+i] ^ c->root_addr[i]) &
+ c->root_addrmsk[i];
+ if (FWINV(verdict != 0, EBT_STP_ROOTADDR))
+ return EBT_NOMATCH;
+ }
+ if (info->bitmask & EBT_STP_ROOTCOST) {
+ v32 = NR32(stpc->root_cost);
+ if (FWINV(v32 < c->root_costl ||
+ v32 > c->root_costu, EBT_STP_ROOTCOST))
+ return EBT_NOMATCH;
+ }
+ if (info->bitmask & EBT_STP_SENDERPRIO) {
+ v16 = NR16(stpc->sender);
+ if (FWINV(v16 < c->sender_priol ||
+ v16 > c->sender_priou, EBT_STP_SENDERPRIO))
+ return EBT_NOMATCH;
+ }
+ if (info->bitmask & EBT_STP_SENDERADDR) {
+ verdict = 0;
+ for (i = 0; i < 6; i++)
+ verdict |= (stpc->sender[2+i] ^ c->sender_addr[i]) &
+ c->sender_addrmsk[i];
+ if (FWINV(verdict != 0, EBT_STP_SENDERADDR))
+ return EBT_NOMATCH;
+ }
+ if (info->bitmask & EBT_STP_PORT) {
+ v16 = NR16(stpc->port);
+ if (FWINV(v16 < c->portl ||
+ v16 > c->portu, EBT_STP_PORT))
+ return EBT_NOMATCH;
+ }
+ if (info->bitmask & EBT_STP_MSGAGE) {
+ v16 = NR16(stpc->msg_age);
+ if (FWINV(v16 < c->msg_agel ||
+ v16 > c->msg_ageu, EBT_STP_MSGAGE))
+ return EBT_NOMATCH;
+ }
+ if (info->bitmask & EBT_STP_MAXAGE) {
+ v16 = NR16(stpc->max_age);
+ if (FWINV(v16 < c->max_agel ||
+ v16 > c->max_ageu, EBT_STP_MAXAGE))
+ return EBT_NOMATCH;
+ }
+ if (info->bitmask & EBT_STP_HELLOTIME) {
+ v16 = NR16(stpc->hello_time);
+ if (FWINV(v16 < c->hello_timel ||
+ v16 > c->hello_timeu, EBT_STP_HELLOTIME))
+ return EBT_NOMATCH;
+ }
+ if (info->bitmask & EBT_STP_FWDD) {
+ v16 = NR16(stpc->forward_delay);
+ if (FWINV(v16 < c->forward_delayl ||
+ v16 > c->forward_delayu, EBT_STP_FWDD))
+ return EBT_NOMATCH;
+ }
+ return EBT_MATCH;
+}
+
+static int ebt_filter_stp(const struct sk_buff *skb, const struct net_device *in,
+ const struct net_device *out, const void *data, unsigned int datalen)
+{
+ struct ebt_stp_info *info = (struct ebt_stp_info *)data;
+ struct stp_header stph;
+ uint8_t header[6] = {0x42, 0x42, 0x03, 0x00, 0x00, 0x00};
+ if (skb_copy_bits(skb, 0, &stph, sizeof(stph)))
+ return EBT_NOMATCH;
+
+ /* The stp code only considers these */
+ if (memcmp(&stph, header, sizeof(header)))
+ return EBT_NOMATCH;
+
+ if (info->bitmask & EBT_STP_TYPE
+ && FWINV(info->type != stph.type, EBT_STP_TYPE))
+ return EBT_NOMATCH;
+
+ if (stph.type == BPDU_TYPE_CONFIG &&
+ info->bitmask & EBT_STP_CONFIG_MASK) {
+ struct stp_config_pdu stpc;
+
+ if (skb_copy_bits(skb, sizeof(stph), &stpc, sizeof(stpc)))
+ return EBT_NOMATCH;
+ return ebt_filter_config(info, &stpc);
+ }
+ return EBT_MATCH;
+}
+
+static int ebt_stp_check(const char *tablename, unsigned int hookmask,
+ const struct ebt_entry *e, void *data, unsigned int datalen)
+{
+ struct ebt_stp_info *info = (struct ebt_stp_info *)data;
+ int len = sizeof(struct ebt_stp_info);
+ uint8_t bridge_ula[6] = { 0x01, 0x80, 0xc2, 0x00, 0x00, 0x00 };
+ uint8_t msk[6] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
+
+ if (info->bitmask & ~EBT_STP_MASK || info->invflags & ~EBT_STP_MASK ||
+ !(info->bitmask & EBT_STP_MASK))
+ return -EINVAL;
+ if (datalen != len)
+ return -EINVAL;
+ /* Make sure the match only receives stp frames */
+ if (memcmp(e->destmac, bridge_ula, ETH_ALEN) ||
+ memcmp(e->destmsk, msk, ETH_ALEN) || !(e->bitmask & EBT_DESTMAC))
+ return -EINVAL;
+
+ return 0;
+}
+
+static struct ebt_match filter_stp =
+{
+ .name = EBT_STP_MATCH,
+ .match = ebt_filter_stp,
+ .check = ebt_stp_check,
+ .me = THIS_MODULE,
+};
+
+static int __init init(void)
+{
+ return ebt_register_match(&filter_stp);
+}
+
+static void __exit fini(void)
+{
+ ebt_unregister_match(&filter_stp);
+}
+
+module_init(init);
+module_exit(fini);
+MODULE_LICENSE("GPL");
--- /dev/null Thu Aug 24 11:00:32 2000
+++ linux-2.6.0-test1/include/linux/netfilter_bridge/ebt_stp.h Thu Jul 17 23:59:10 2003
@@ -0,0 +1,46 @@
+#ifndef __LINUX_BRIDGE_EBT_STP_H
+#define __LINUX_BRIDGE_EBT_STP_H
+
+#define EBT_STP_TYPE 0x0001
+
+#define EBT_STP_FLAGS 0x0002
+#define EBT_STP_ROOTPRIO 0x0004
+#define EBT_STP_ROOTADDR 0x0008
+#define EBT_STP_ROOTCOST 0x0010
+#define EBT_STP_SENDERPRIO 0x0020
+#define EBT_STP_SENDERADDR 0x0040
+#define EBT_STP_PORT 0x0080
+#define EBT_STP_MSGAGE 0x0100
+#define EBT_STP_MAXAGE 0x0200
+#define EBT_STP_HELLOTIME 0x0400
+#define EBT_STP_FWDD 0x0800
+
+#define EBT_STP_MASK 0x0fff
+#define EBT_STP_CONFIG_MASK 0x0ffe
+
+#define EBT_STP_MATCH "stp"
+
+struct ebt_stp_config_info
+{
+ uint8_t flags;
+ uint16_t root_priol, root_priou;
+ char root_addr[6], root_addrmsk[6];
+ uint32_t root_costl, root_costu;
+ uint16_t sender_priol, sender_priou;
+ char sender_addr[6], sender_addrmsk[6];
+ uint16_t portl, portu;
+ uint16_t msg_agel, msg_ageu;
+ uint16_t max_agel, max_ageu;
+ uint16_t hello_timel, hello_timeu;
+ uint16_t forward_delayl, forward_delayu;
+};
+
+struct ebt_stp_info
+{
+ uint8_t type;
+ struct ebt_stp_config_info config;
+ uint16_t bitmask;
+ uint16_t invflags;
+};
+
+#endif
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