--- /dev/null
+/*
+ * Spanning tree protocol; BPDU handling
+ * Linux ethernet bridge
+ *
+ * Authors:
+ * Lennert Buytenhek <buytenh@gnu.org>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/netfilter_bridge.h>
+#include <linux/etherdevice.h>
+#include <linux/llc.h>
+#include <linux/slab.h>
+#include <linux/pkt_sched.h>
+#include <net/net_namespace.h>
+#include <net/llc.h>
+#include <net/llc_pdu.h>
+#include <net/stp.h>
+#include <asm/unaligned.h>
+
+#include "br_private.h"
+#include "br_private_stp.h"
+
+#define STP_HZ 256
+
+#define LLC_RESERVE sizeof(struct llc_pdu_un)
+
+static void br_send_bpdu(struct net_bridge_port *p,
+ const unsigned char *data, int length)
+{
+ struct sk_buff *skb;
+
+ skb = dev_alloc_skb(length+LLC_RESERVE);
+ if (!skb)
+ return;
+
+ skb->dev = p->dev;
+ skb->protocol = htons(ETH_P_802_2);
+ skb->priority = TC_PRIO_CONTROL;
+
+ skb_reserve(skb, LLC_RESERVE);
+ memcpy(__skb_put(skb, length), data, length);
+
+ llc_pdu_header_init(skb, LLC_PDU_TYPE_U, LLC_SAP_BSPAN,
+ LLC_SAP_BSPAN, LLC_PDU_CMD);
+ llc_pdu_init_as_ui_cmd(skb);
+
+ llc_mac_hdr_init(skb, p->dev->dev_addr, p->br->group_addr);
+
+ skb_reset_mac_header(skb);
+
+ NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_OUT, NULL, skb,
+ NULL, skb->dev,
+ dev_queue_xmit_sk);
+}
+
+static inline void br_set_ticks(unsigned char *dest, int j)
+{
+ unsigned long ticks = (STP_HZ * j)/ HZ;
+
+ put_unaligned_be16(ticks, dest);
+}
+
+static inline int br_get_ticks(const unsigned char *src)
+{
+ unsigned long ticks = get_unaligned_be16(src);
+
+ return DIV_ROUND_UP(ticks * HZ, STP_HZ);
+}
+
+/* called under bridge lock */
+void br_send_config_bpdu(struct net_bridge_port *p, struct br_config_bpdu *bpdu)
+{
+ unsigned char buf[35];
+
+ if (p->br->stp_enabled != BR_KERNEL_STP)
+ return;
+
+ buf[0] = 0;
+ buf[1] = 0;
+ buf[2] = 0;
+ buf[3] = BPDU_TYPE_CONFIG;
+ buf[4] = (bpdu->topology_change ? 0x01 : 0) |
+ (bpdu->topology_change_ack ? 0x80 : 0);
+ buf[5] = bpdu->root.prio[0];
+ buf[6] = bpdu->root.prio[1];
+ buf[7] = bpdu->root.addr[0];
+ buf[8] = bpdu->root.addr[1];
+ buf[9] = bpdu->root.addr[2];
+ buf[10] = bpdu->root.addr[3];
+ buf[11] = bpdu->root.addr[4];
+ buf[12] = bpdu->root.addr[5];
+ buf[13] = (bpdu->root_path_cost >> 24) & 0xFF;
+ buf[14] = (bpdu->root_path_cost >> 16) & 0xFF;
+ buf[15] = (bpdu->root_path_cost >> 8) & 0xFF;
+ buf[16] = bpdu->root_path_cost & 0xFF;
+ buf[17] = bpdu->bridge_id.prio[0];
+ buf[18] = bpdu->bridge_id.prio[1];
+ buf[19] = bpdu->bridge_id.addr[0];
+ buf[20] = bpdu->bridge_id.addr[1];
+ buf[21] = bpdu->bridge_id.addr[2];
+ buf[22] = bpdu->bridge_id.addr[3];
+ buf[23] = bpdu->bridge_id.addr[4];
+ buf[24] = bpdu->bridge_id.addr[5];
+ buf[25] = (bpdu->port_id >> 8) & 0xFF;
+ buf[26] = bpdu->port_id & 0xFF;
+
+ br_set_ticks(buf+27, bpdu->message_age);
+ br_set_ticks(buf+29, bpdu->max_age);
+ br_set_ticks(buf+31, bpdu->hello_time);
+ br_set_ticks(buf+33, bpdu->forward_delay);
+
+ br_send_bpdu(p, buf, 35);
+}
+
+/* called under bridge lock */
+void br_send_tcn_bpdu(struct net_bridge_port *p)
+{
+ unsigned char buf[4];
+
+ if (p->br->stp_enabled != BR_KERNEL_STP)
+ return;
+
+ buf[0] = 0;
+ buf[1] = 0;
+ buf[2] = 0;
+ buf[3] = BPDU_TYPE_TCN;
+ br_send_bpdu(p, buf, 4);
+}
+
+/*
+ * Called from llc.
+ *
+ * NO locks, but rcu_read_lock
+ */
+void br_stp_rcv(const struct stp_proto *proto, struct sk_buff *skb,
+ struct net_device *dev)
+{
+ const unsigned char *dest = eth_hdr(skb)->h_dest;
+ struct net_bridge_port *p;
+ struct net_bridge *br;
+ const unsigned char *buf;
+
+ if (!pskb_may_pull(skb, 4))
+ goto err;
+
+ /* compare of protocol id and version */
+ buf = skb->data;
+ if (buf[0] != 0 || buf[1] != 0 || buf[2] != 0)
+ goto err;
+
+ p = br_port_get_check_rcu(dev);
+ if (!p)
+ goto err;
+
+ br = p->br;
+ spin_lock(&br->lock);
+
+ if (br->stp_enabled != BR_KERNEL_STP)
+ goto out;
+
+ if (!(br->dev->flags & IFF_UP))
+ goto out;
+
+ if (p->state == BR_STATE_DISABLED)
+ goto out;
+
+ if (!ether_addr_equal(dest, br->group_addr))
+ goto out;
+
+ if (p->flags & BR_BPDU_GUARD) {
+ br_notice(br, "BPDU received on blocked port %u(%s)\n",
+ (unsigned int) p->port_no, p->dev->name);
+ br_stp_disable_port(p);
+ goto out;
+ }
+
+ buf = skb_pull(skb, 3);
+
+ if (buf[0] == BPDU_TYPE_CONFIG) {
+ struct br_config_bpdu bpdu;
+
+ if (!pskb_may_pull(skb, 32))
+ goto out;
+
+ buf = skb->data;
+ bpdu.topology_change = (buf[1] & 0x01) ? 1 : 0;
+ bpdu.topology_change_ack = (buf[1] & 0x80) ? 1 : 0;
+
+ bpdu.root.prio[0] = buf[2];
+ bpdu.root.prio[1] = buf[3];
+ bpdu.root.addr[0] = buf[4];
+ bpdu.root.addr[1] = buf[5];
+ bpdu.root.addr[2] = buf[6];
+ bpdu.root.addr[3] = buf[7];
+ bpdu.root.addr[4] = buf[8];
+ bpdu.root.addr[5] = buf[9];
+ bpdu.root_path_cost =
+ (buf[10] << 24) |
+ (buf[11] << 16) |
+ (buf[12] << 8) |
+ buf[13];
+ bpdu.bridge_id.prio[0] = buf[14];
+ bpdu.bridge_id.prio[1] = buf[15];
+ bpdu.bridge_id.addr[0] = buf[16];
+ bpdu.bridge_id.addr[1] = buf[17];
+ bpdu.bridge_id.addr[2] = buf[18];
+ bpdu.bridge_id.addr[3] = buf[19];
+ bpdu.bridge_id.addr[4] = buf[20];
+ bpdu.bridge_id.addr[5] = buf[21];
+ bpdu.port_id = (buf[22] << 8) | buf[23];
+
+ bpdu.message_age = br_get_ticks(buf+24);
+ bpdu.max_age = br_get_ticks(buf+26);
+ bpdu.hello_time = br_get_ticks(buf+28);
+ bpdu.forward_delay = br_get_ticks(buf+30);
+
+ if (bpdu.message_age > bpdu.max_age) {
+ if (net_ratelimit())
+ br_notice(p->br,
+ "port %u config from %pM"
+ " (message_age %ul > max_age %ul)\n",
+ p->port_no,
+ eth_hdr(skb)->h_source,
+ bpdu.message_age, bpdu.max_age);
+ goto out;
+ }
+
+ br_received_config_bpdu(p, &bpdu);
+ } else if (buf[0] == BPDU_TYPE_TCN) {
+ br_received_tcn_bpdu(p);
+ }
+ out:
+ spin_unlock(&br->lock);
+ err:
+ kfree_skb(skb);
+}
Code Review / kvmfornfv.git / blobdiff