-/*
- * Copyright (c) 2008, 2009, 2010 Nicira Networks.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at:
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-/* Based on sample implementation in 802.1D-1998. Above copyright and license
- * applies to all modifications. */
-
-#include <config.h>
-
-#include "stp.h"
-#include <sys/types.h>
-#include <netinet/in.h>
-#include <arpa/inet.h>
-#include <assert.h>
-#include <inttypes.h>
-#include <stdlib.h>
-#include "ofpbuf.h"
-#include "packets.h"
-#include "util.h"
-#include "vlog.h"
-#include "xtoxll.h"
-
-VLOG_DEFINE_THIS_MODULE(stp)
-
-/* Ethernet address used as the destination for STP frames. */
-const uint8_t stp_eth_addr[ETH_ADDR_LEN]
-= { 0x01, 0x80, 0xC2, 0x00, 0x00, 0x01 };
-
-#define STP_PROTOCOL_ID 0x0000
-#define STP_PROTOCOL_VERSION 0x00
-#define STP_TYPE_CONFIG 0x00
-#define STP_TYPE_TCN 0x80
-
-struct stp_bpdu_header {
- uint16_t protocol_id; /* STP_PROTOCOL_ID. */
- uint8_t protocol_version; /* STP_PROTOCOL_VERSION. */
- uint8_t bpdu_type; /* One of STP_TYPE_*. */
-} __attribute__((packed));
-BUILD_ASSERT_DECL(sizeof(struct stp_bpdu_header) == 4);
-
-enum stp_config_bpdu_flags {
- STP_CONFIG_TOPOLOGY_CHANGE_ACK = 0x80,
- STP_CONFIG_TOPOLOGY_CHANGE = 0x01
-};
-
-struct stp_config_bpdu {
- struct stp_bpdu_header header; /* Type STP_TYPE_CONFIG. */
- uint8_t flags; /* STP_CONFIG_* flags. */
- uint64_t root_id; /* 8.5.1.1: Bridge believed to be root. */
- uint32_t root_path_cost; /* 8.5.1.2: Cost of path to root. */
- uint64_t bridge_id; /* 8.5.1.3: ID of transmitting bridge. */
- uint16_t port_id; /* 8.5.1.4: Port transmitting the BPDU. */
- uint16_t message_age; /* 8.5.1.5: Age of BPDU at tx time. */
- uint16_t max_age; /* 8.5.1.6: Timeout for received data. */
- uint16_t hello_time; /* 8.5.1.7: Time between BPDU generation. */
- uint16_t forward_delay; /* 8.5.1.8: State progression delay. */
-} __attribute__((packed));
-BUILD_ASSERT_DECL(sizeof(struct stp_config_bpdu) == 35);
-
-struct stp_tcn_bpdu {
- struct stp_bpdu_header header; /* Type STP_TYPE_TCN. */
-} __attribute__((packed));
-BUILD_ASSERT_DECL(sizeof(struct stp_tcn_bpdu) == 4);
-
-struct stp_timer {
- bool active; /* Timer in use? */
- int value; /* Current value of timer, counting up. */
-};
-
-struct stp_port {
- struct stp *stp;
- int port_id; /* 8.5.5.1: Unique port identifier. */
- enum stp_state state; /* 8.5.5.2: Current state. */
- int path_cost; /* 8.5.5.3: Cost of tx/rx on this port. */
- stp_identifier designated_root; /* 8.5.5.4. */
- int designated_cost; /* 8.5.5.5: Path cost to root on port. */
- stp_identifier designated_bridge; /* 8.5.5.6. */
- int designated_port; /* 8.5.5.7: Port to send config msgs on. */
- bool topology_change_ack; /* 8.5.5.8: Flag for next config BPDU. */
- bool config_pending; /* 8.5.5.9: Send BPDU when hold expires? */
- bool change_detection_enabled; /* 8.5.5.10: Detect topology changes? */
-
- struct stp_timer message_age_timer; /* 8.5.6.1: Age of received info. */
- struct stp_timer forward_delay_timer; /* 8.5.6.2: State change timer. */
- struct stp_timer hold_timer; /* 8.5.6.3: BPDU rate limit timer. */
-
- bool state_changed;
-};
-
-struct stp {
- /* Static bridge data. */
- char *name; /* Human-readable name for log messages. */
- stp_identifier bridge_id; /* 8.5.3.7: This bridge. */
- int max_age; /* 8.5.3.4: Time to drop received data. */
- int hello_time; /* 8.5.3.5: Time between sending BPDUs. */
- int forward_delay; /* 8.5.3.6: Delay between state changes. */
- int bridge_max_age; /* 8.5.3.8: max_age when we're root. */
- int bridge_hello_time; /* 8.5.3.9: hello_time as root. */
- int bridge_forward_delay; /* 8.5.3.10: forward_delay as root. */
- int rq_max_age; /* User-requested max age, in ms. */
- int rq_hello_time; /* User-requested hello time, in ms. */
- int rq_forward_delay; /* User-requested forward delay, in ms. */
- int elapsed_remainder; /* Left-over msecs from last stp_tick(). */
-
- /* Dynamic bridge data. */
- stp_identifier designated_root; /* 8.5.3.1: Bridge believed to be root. */
- unsigned int root_path_cost; /* 8.5.3.2: Cost of path to root. */
- struct stp_port *root_port; /* 8.5.3.3: Lowest cost port to root. */
- bool topology_change_detected; /* 8.5.3.11: Detected a topology change? */
- bool topology_change; /* 8.5.3.12: Received topology change? */
-
- /* Bridge timers. */
- struct stp_timer hello_timer; /* 8.5.4.1: Hello timer. */
- struct stp_timer tcn_timer; /* 8.5.4.2: Topology change timer. */
- struct stp_timer topology_change_timer; /* 8.5.4.3. */
-
- /* Ports. */
- struct stp_port ports[STP_MAX_PORTS];
-
- /* Interface to client. */
- struct stp_port *first_changed_port;
- void (*send_bpdu)(struct ofpbuf *bpdu, int port_no, void *aux);
- void *aux;
-};
-
-#define FOR_EACH_ENABLED_PORT(PORT, STP) \
- for ((PORT) = stp_next_enabled_port((STP), (STP)->ports); \
- (PORT); \
- (PORT) = stp_next_enabled_port((STP), (PORT) + 1))
-static struct stp_port *
-stp_next_enabled_port(const struct stp *stp, const struct stp_port *port)
-{
- for (; port < &stp->ports[ARRAY_SIZE(stp->ports)]; port++) {
- if (port->state != STP_DISABLED) {
- return (struct stp_port *) port;
- }
- }
- return NULL;
-}
-
-#define MESSAGE_AGE_INCREMENT 1
-
-static void stp_transmit_config(struct stp_port *);
-static bool stp_supersedes_port_info(const struct stp_port *,
- const struct stp_config_bpdu *);
-static void stp_record_config_information(struct stp_port *,
- const struct stp_config_bpdu *);
-static void stp_record_config_timeout_values(struct stp *,
- const struct stp_config_bpdu *);
-static bool stp_is_designated_port(const struct stp_port *);
-static void stp_config_bpdu_generation(struct stp *);
-static void stp_transmit_tcn(struct stp *);
-static void stp_configuration_update(struct stp *);
-static bool stp_supersedes_root(const struct stp_port *root,
- const struct stp_port *);
-static void stp_root_selection(struct stp *);
-static void stp_designated_port_selection(struct stp *);
-static void stp_become_designated_port(struct stp_port *);
-static void stp_port_state_selection(struct stp *);
-static void stp_make_forwarding(struct stp_port *);
-static void stp_make_blocking(struct stp_port *);
-static void stp_set_port_state(struct stp_port *, enum stp_state);
-static void stp_topology_change_detection(struct stp *);
-static void stp_topology_change_acknowledged(struct stp *);
-static void stp_acknowledge_topology_change(struct stp_port *);
-static void stp_received_config_bpdu(struct stp *, struct stp_port *,
- const struct stp_config_bpdu *);
-static void stp_received_tcn_bpdu(struct stp *, struct stp_port *);
-static void stp_hello_timer_expiry(struct stp *);
-static void stp_message_age_timer_expiry(struct stp_port *);
-static bool stp_is_designated_for_some_port(const struct stp *);
-static void stp_forward_delay_timer_expiry(struct stp_port *);
-static void stp_tcn_timer_expiry(struct stp *);
-static void stp_topology_change_timer_expiry(struct stp *);
-static void stp_hold_timer_expiry(struct stp_port *);
-static void stp_initialize_port(struct stp_port *, enum stp_state);
-static void stp_become_root_bridge(struct stp *);
-static void stp_update_bridge_timers(struct stp *);
-
-static int clamp(int x, int min, int max);
-static int ms_to_timer(int ms);
-static int ms_to_timer_remainder(int ms);
-static int timer_to_ms(int timer);
-static void stp_start_timer(struct stp_timer *, int value);
-static void stp_stop_timer(struct stp_timer *);
-static bool stp_timer_expired(struct stp_timer *, int elapsed, int timeout);
-
-static void stp_send_bpdu(struct stp_port *, const void *, size_t);
-
-/* Creates and returns a new STP instance that initially has no ports enabled.
- *
- * 'bridge_id' should be a 48-bit MAC address as returned by
- * eth_addr_to_uint64(). 'bridge_id' may also have a priority value in its top
- * 16 bits; if those bits are set to 0, STP_DEFAULT_BRIDGE_PRIORITY is used.
- * (This priority may be changed with stp_set_bridge_priority().)
- *
- * When the bridge needs to send out a BPDU, it calls 'send_bpdu'. This
- * callback may be called from stp_tick() or stp_received_bpdu(). The
- * arguments to 'send_bpdu' are an STP BPDU encapsulated in
- */
-struct stp *
-stp_create(const char *name, stp_identifier bridge_id,
- void (*send_bpdu)(struct ofpbuf *bpdu, int port_no, void *aux),
- void *aux)
-{
- struct stp *stp;
- struct stp_port *p;
-
- stp = xzalloc(sizeof *stp);
- stp->name = xstrdup(name);
- stp->bridge_id = bridge_id;
- if (!(stp->bridge_id >> 48)) {
- stp->bridge_id |= (uint64_t) STP_DEFAULT_BRIDGE_PRIORITY << 48;
- }
-
- stp->rq_max_age = 6000;
- stp->rq_hello_time = 2000;
- stp->rq_forward_delay = 4000;
- stp_update_bridge_timers(stp);
- stp->max_age = stp->bridge_max_age;
- stp->hello_time = stp->bridge_hello_time;
- stp->forward_delay = stp->bridge_forward_delay;
-
- stp->designated_root = stp->bridge_id;
- stp->root_path_cost = 0;
- stp->root_port = NULL;
- stp->topology_change_detected = false;
- stp->topology_change = false;
-
- stp_stop_timer(&stp->tcn_timer);
- stp_stop_timer(&stp->topology_change_timer);
- stp_start_timer(&stp->hello_timer, 0);
-
- stp->send_bpdu = send_bpdu;
- stp->aux = aux;
-
- stp->first_changed_port = &stp->ports[ARRAY_SIZE(stp->ports)];
- for (p = stp->ports; p < &stp->ports[ARRAY_SIZE(stp->ports)]; p++) {
- p->stp = stp;
- p->port_id = (stp_port_no(p) + 1) | (STP_DEFAULT_PORT_PRIORITY << 8);
- p->path_cost = 19; /* Recommended default for 100 Mb/s link. */
- stp_initialize_port(p, STP_DISABLED);
- }
- return stp;
-}
-
-/* Destroys 'stp'. */
-void
-stp_destroy(struct stp *stp)
-{
- if (stp) {
- free(stp->name);
- free(stp);
- }
-}
-
-/* Runs 'stp' given that 'ms' milliseconds have passed. */
-void
-stp_tick(struct stp *stp, int ms)
-{
- struct stp_port *p;
- int elapsed;
-
- /* Convert 'ms' to STP timer ticks. Preserve any leftover milliseconds
- * from previous stp_tick() calls so that we don't lose STP ticks when we
- * are called too frequently. */
- ms = clamp(ms, 0, INT_MAX - 1000) + stp->elapsed_remainder;
- elapsed = ms_to_timer(ms);
- stp->elapsed_remainder = ms_to_timer_remainder(ms);
- if (!elapsed) {
- return;
- }
-
- if (stp_timer_expired(&stp->hello_timer, elapsed, stp->hello_time)) {
- stp_hello_timer_expiry(stp);
- }
- if (stp_timer_expired(&stp->tcn_timer, elapsed, stp->bridge_hello_time)) {
- stp_tcn_timer_expiry(stp);
- }
- if (stp_timer_expired(&stp->topology_change_timer, elapsed,
- stp->max_age + stp->forward_delay)) {
- stp_topology_change_timer_expiry(stp);
- }
- FOR_EACH_ENABLED_PORT (p, stp) {
- if (stp_timer_expired(&p->message_age_timer, elapsed, stp->max_age)) {
- stp_message_age_timer_expiry(p);
- }
- }
- FOR_EACH_ENABLED_PORT (p, stp) {
- if (stp_timer_expired(&p->forward_delay_timer, elapsed,
- stp->forward_delay)) {
- stp_forward_delay_timer_expiry(p);
- }
- if (stp_timer_expired(&p->hold_timer, elapsed, ms_to_timer(1000))) {
- stp_hold_timer_expiry(p);
- }
- }
-}
-
-static void
-set_bridge_id(struct stp *stp, stp_identifier new_bridge_id)
-{
- if (new_bridge_id != stp->bridge_id) {
- bool root;
- struct stp_port *p;
-
- root = stp_is_root_bridge(stp);
- FOR_EACH_ENABLED_PORT (p, stp) {
- if (stp_is_designated_port(p)) {
- p->designated_bridge = new_bridge_id;
- }
- }
- stp->bridge_id = new_bridge_id;
- stp_configuration_update(stp);
- stp_port_state_selection(stp);
- if (stp_is_root_bridge(stp) && !root) {
- stp_become_root_bridge(stp);
- }
- }
-}
-
-void
-stp_set_bridge_id(struct stp *stp, stp_identifier bridge_id)
-{
- const uint64_t mac_bits = (UINT64_C(1) << 48) - 1;
- const uint64_t pri_bits = ~mac_bits;
- set_bridge_id(stp, (stp->bridge_id & pri_bits) | (bridge_id & mac_bits));
-}
-
-void
-stp_set_bridge_priority(struct stp *stp, uint16_t new_priority)
-{
- const uint64_t mac_bits = (UINT64_C(1) << 48) - 1;
- set_bridge_id(stp, ((stp->bridge_id & mac_bits)
- | ((uint64_t) new_priority << 48)));
-}
-
-/* Sets the desired hello time for 'stp' to 'ms', in milliseconds. The actual
- * hello time is clamped to the range of 1 to 10 seconds and subject to the
- * relationship (bridge_max_age >= 2 * (bridge_hello_time + 1 s)). The bridge
- * hello time is only used when 'stp' is the root bridge. */
-void
-stp_set_hello_time(struct stp *stp, int ms)
-{
- stp->rq_hello_time = ms;
- stp_update_bridge_timers(stp);
-}
-
-/* Sets the desired max age for 'stp' to 'ms', in milliseconds. The actual max
- * age is clamped to the range of 6 to 40 seconds and subject to the
- * relationships (2 * (bridge_forward_delay - 1 s) >= bridge_max_age) and
- * (bridge_max_age >= 2 * (bridge_hello_time + 1 s)). The bridge max age is
- * only used when 'stp' is the root bridge. */
-void
-stp_set_max_age(struct stp *stp, int ms)
-{
- stp->rq_max_age = ms;
- stp_update_bridge_timers(stp);
-}
-
-/* Sets the desired forward delay for 'stp' to 'ms', in milliseconds. The
- * actual forward delay is clamped to the range of 4 to 30 seconds and subject
- * to the relationship (2 * (bridge_forward_delay - 1 s) >= bridge_max_age).
- * The bridge forward delay is only used when 'stp' is the root bridge. */
-void
-stp_set_forward_delay(struct stp *stp, int ms)
-{
- stp->rq_forward_delay = ms;
- stp_update_bridge_timers(stp);
-}
-
-/* Returns the name given to 'stp' in the call to stp_create(). */
-const char *
-stp_get_name(const struct stp *stp)
-{
- return stp->name;
-}
-
-/* Returns the bridge ID for 'stp'. */
-stp_identifier
-stp_get_bridge_id(const struct stp *stp)
-{
- return stp->bridge_id;
-}
-
-/* Returns the bridge ID of the bridge currently believed to be the root. */
-stp_identifier
-stp_get_designated_root(const struct stp *stp)
-{
- return stp->designated_root;
-}
-
-/* Returns true if 'stp' believes itself to the be root of the spanning tree,
- * false otherwise. */
-bool
-stp_is_root_bridge(const struct stp *stp)
-{
- return stp->bridge_id == stp->designated_root;
-}
-
-/* Returns the cost of the path from 'stp' to the root of the spanning tree. */
-int
-stp_get_root_path_cost(const struct stp *stp)
-{
- return stp->root_path_cost;
-}
-
-/* Returns the bridge hello time, in ms. The returned value is not necessarily
- * the value passed to stp_set_hello_time(): it is clamped to the valid range
- * and quantized to the STP timer resolution. */
-int
-stp_get_hello_time(const struct stp *stp)
-{
- return timer_to_ms(stp->bridge_hello_time);
-}
-
-/* Returns the bridge max age, in ms. The returned value is not necessarily
- * the value passed to stp_set_max_age(): it is clamped to the valid range,
- * quantized to the STP timer resolution, and adjusted to match the constraints
- * due to the hello time. */
-int
-stp_get_max_age(const struct stp *stp)
-{
- return timer_to_ms(stp->bridge_max_age);
-}
-
-/* Returns the bridge forward delay, in ms. The returned value is not
- * necessarily the value passed to stp_set_forward_delay(): it is clamped to
- * the valid range, quantized to the STP timer resolution, and adjusted to
- * match the constraints due to the forward delay. */
-int
-stp_get_forward_delay(const struct stp *stp)
-{
- return timer_to_ms(stp->bridge_forward_delay);
-}
-
-/* Returns the port in 'stp' with index 'port_no', which must be between 0 and
- * STP_MAX_PORTS. */
-struct stp_port *
-stp_get_port(struct stp *stp, int port_no)
-{
- assert(port_no >= 0 && port_no < ARRAY_SIZE(stp->ports));
- return &stp->ports[port_no];
-}
-
-/* Returns the port connecting 'stp' to the root bridge, or a null pointer if
- * there is no such port. */
-struct stp_port *
-stp_get_root_port(struct stp *stp)
-{
- return stp->root_port;
-}
-
-/* Finds a port whose state has changed. If successful, stores the port whose
- * state changed in '*portp' and returns true. If no port has changed, stores
- * NULL in '*portp' and returns false. */
-bool
-stp_get_changed_port(struct stp *stp, struct stp_port **portp)
-{
- struct stp_port *end = &stp->ports[ARRAY_SIZE(stp->ports)];
- struct stp_port *p;
-
- for (p = stp->first_changed_port; p < end; p++) {
- if (p->state_changed) {
- p->state_changed = false;
- stp->first_changed_port = p + 1;
- *portp = p;
- return true;
- }
- }
- stp->first_changed_port = end;
- *portp = NULL;
- return false;
-}
-
-/* Returns the name for the given 'state' (for use in debugging and log
- * messages). */
-const char *
-stp_state_name(enum stp_state state)
-{
- switch (state) {
- case STP_DISABLED:
- return "disabled";
- case STP_LISTENING:
- return "listening";
- case STP_LEARNING:
- return "learning";
- case STP_FORWARDING:
- return "forwarding";
- case STP_BLOCKING:
- return "blocking";
- default:
- NOT_REACHED();
- }
-}
-
-/* Returns true if 'state' is one in which packets received on a port should
- * be forwarded, false otherwise.
- *
- * Returns true if 'state' is STP_DISABLED, since presumably in that case the
- * port should still work, just not have STP applied to it. */
-bool
-stp_forward_in_state(enum stp_state state)
-{
- return (state & (STP_DISABLED | STP_FORWARDING)) != 0;
-}
-
-/* Returns true if 'state' is one in which MAC learning should be done on
- * packets received on a port, false otherwise.
- *
- * Returns true if 'state' is STP_DISABLED, since presumably in that case the
- * port should still work, just not have STP applied to it. */
-bool
-stp_learn_in_state(enum stp_state state)
-{
- return (state & (STP_DISABLED | STP_LEARNING | STP_FORWARDING)) != 0;
-}
-
-/* Notifies the STP entity that bridge protocol data unit 'bpdu', which is
- * 'bpdu_size' bytes in length, was received on port 'p'.
- *
- * This function may call the 'send_bpdu' function provided to stp_create(). */
-void
-stp_received_bpdu(struct stp_port *p, const void *bpdu, size_t bpdu_size)
-{
- struct stp *stp = p->stp;
- const struct stp_bpdu_header *header;
-
- if (p->state == STP_DISABLED) {
- return;
- }
-
- if (bpdu_size < sizeof(struct stp_bpdu_header)) {
- VLOG_WARN("%s: received runt %zu-byte BPDU", stp->name, bpdu_size);
- return;
- }
-
- header = bpdu;
- if (header->protocol_id != htons(STP_PROTOCOL_ID)) {
- VLOG_WARN("%s: received BPDU with unexpected protocol ID %"PRIu16,
- stp->name, ntohs(header->protocol_id));
- return;
- }
- if (header->protocol_version != STP_PROTOCOL_VERSION) {
- VLOG_DBG("%s: received BPDU with unexpected protocol version %"PRIu8,
- stp->name, header->protocol_version);
- }
-
- switch (header->bpdu_type) {
- case STP_TYPE_CONFIG:
- if (bpdu_size < sizeof(struct stp_config_bpdu)) {
- VLOG_WARN("%s: received config BPDU with invalid size %zu",
- stp->name, bpdu_size);
- return;
- }
- stp_received_config_bpdu(stp, p, bpdu);
- break;
-
- case STP_TYPE_TCN:
- if (bpdu_size != sizeof(struct stp_tcn_bpdu)) {
- VLOG_WARN("%s: received TCN BPDU with invalid size %zu",
- stp->name, bpdu_size);
- return;
- }
- stp_received_tcn_bpdu(stp, p);
- break;
-
- default:
- VLOG_WARN("%s: received BPDU of unexpected type %"PRIu8,
- stp->name, header->bpdu_type);
- return;
- }
-}
-
-/* Returns the STP entity in which 'p' is nested. */
-struct stp *
-stp_port_get_stp(struct stp_port *p)
-{
- return p->stp;
-}
-
-/* Returns the index of port 'p' within its bridge. */
-int
-stp_port_no(const struct stp_port *p)
-{
- struct stp *stp = p->stp;
- assert(p >= stp->ports && p < &stp->ports[ARRAY_SIZE(stp->ports)]);
- return p - stp->ports;
-}
-
-/* Returns the state of port 'p'. */
-enum stp_state
-stp_port_get_state(const struct stp_port *p)
-{
- return p->state;
-}
-
-/* Disables STP on port 'p'. */
-void
-stp_port_disable(struct stp_port *p)
-{
- struct stp *stp = p->stp;
- if (p->state != STP_DISABLED) {
- bool root = stp_is_root_bridge(stp);
- stp_become_designated_port(p);
- stp_set_port_state(p, STP_DISABLED);
- p->topology_change_ack = false;
- p->config_pending = false;
- stp_stop_timer(&p->message_age_timer);
- stp_stop_timer(&p->forward_delay_timer);
- stp_configuration_update(stp);
- stp_port_state_selection(stp);
- if (stp_is_root_bridge(stp) && !root) {
- stp_become_root_bridge(stp);
- }
- }
-}
-
-/* Enables STP on port 'p'. The port will initially be in "blocking" state. */
-void
-stp_port_enable(struct stp_port *p)
-{
- if (p->state == STP_DISABLED) {
- stp_initialize_port(p, STP_BLOCKING);
- stp_port_state_selection(p->stp);
- }
-}
-
-/* Sets the priority of port 'p' to 'new_priority'. Lower numerical values
- * are interpreted as higher priorities. */
-void
-stp_port_set_priority(struct stp_port *p, uint8_t new_priority)
-{
- uint16_t new_port_id = (p->port_id & 0xff) | (new_priority << 8);
- if (p->port_id != new_port_id) {
- struct stp *stp = p->stp;
- if (stp_is_designated_port(p)) {
- p->designated_port = new_port_id;
- }
- p->port_id = new_port_id;
- if (stp->bridge_id == p->designated_bridge
- && p->port_id < p->designated_port) {
- stp_become_designated_port(p);
- stp_port_state_selection(stp);
- }
- }
-}
-
-/* Sets the path cost of port 'p' to 'path_cost'. Lower values are generally
- * used to indicate faster links. Use stp_port_set_speed() to automatically
- * generate a default path cost from a link speed. */
-void
-stp_port_set_path_cost(struct stp_port *p, uint16_t path_cost)
-{
- if (p->path_cost != path_cost) {
- struct stp *stp = p->stp;
- p->path_cost = path_cost;
- stp_configuration_update(stp);
- stp_port_state_selection(stp);
- }
-}
-
-/* Sets the path cost of port 'p' based on 'speed' (measured in Mb/s). */
-void
-stp_port_set_speed(struct stp_port *p, unsigned int speed)
-{
- stp_port_set_path_cost(p, (speed >= 10000 ? 2 /* 10 Gb/s. */
- : speed >= 1000 ? 4 /* 1 Gb/s. */
- : speed >= 100 ? 19 /* 100 Mb/s. */
- : speed >= 16 ? 62 /* 16 Mb/s. */
- : speed >= 10 ? 100 /* 10 Mb/s. */
- : speed >= 4 ? 250 /* 4 Mb/s. */
- : 19)); /* 100 Mb/s (guess). */
-}
-
-/* Enables topology change detection on port 'p'. */
-void
-stp_port_enable_change_detection(struct stp_port *p)
-{
- p->change_detection_enabled = true;
-}
-
-/* Disables topology change detection on port 'p'. */
-void
-stp_port_disable_change_detection(struct stp_port *p)
-{
- p->change_detection_enabled = false;
-}
-\f
-static void
-stp_transmit_config(struct stp_port *p)
-{
- struct stp *stp = p->stp;
- bool root = stp_is_root_bridge(stp);
- if (!root && !stp->root_port) {
- return;
- }
- if (p->hold_timer.active) {
- p->config_pending = true;
- } else {
- struct stp_config_bpdu config;
- memset(&config, 0, sizeof config);
- config.header.protocol_id = htons(STP_PROTOCOL_ID);
- config.header.protocol_version = STP_PROTOCOL_VERSION;
- config.header.bpdu_type = STP_TYPE_CONFIG;
- config.flags = 0;
- if (p->topology_change_ack) {
- config.flags |= htons(STP_CONFIG_TOPOLOGY_CHANGE_ACK);
- }
- if (stp->topology_change) {
- config.flags |= htons(STP_CONFIG_TOPOLOGY_CHANGE);
- }
- config.root_id = htonll(stp->designated_root);
- config.root_path_cost = htonl(stp->root_path_cost);
- config.bridge_id = htonll(stp->bridge_id);
- config.port_id = htons(p->port_id);
- if (root) {
- config.message_age = htons(0);
- } else {
- config.message_age = htons(stp->root_port->message_age_timer.value
- + MESSAGE_AGE_INCREMENT);
- }
- config.max_age = htons(stp->max_age);
- config.hello_time = htons(stp->hello_time);
- config.forward_delay = htons(stp->forward_delay);
- if (ntohs(config.message_age) < stp->max_age) {
- p->topology_change_ack = false;
- p->config_pending = false;
- stp_send_bpdu(p, &config, sizeof config);
- stp_start_timer(&p->hold_timer, 0);
- }
- }
-}
-
-static bool
-stp_supersedes_port_info(const struct stp_port *p,
- const struct stp_config_bpdu *config)
-{
- if (ntohll(config->root_id) != p->designated_root) {
- return ntohll(config->root_id) < p->designated_root;
- } else if (ntohl(config->root_path_cost) != p->designated_cost) {
- return ntohl(config->root_path_cost) < p->designated_cost;
- } else if (ntohll(config->bridge_id) != p->designated_bridge) {
- return ntohll(config->bridge_id) < p->designated_bridge;
- } else {
- return (ntohll(config->bridge_id) != p->stp->bridge_id
- || ntohs(config->port_id) <= p->designated_port);
- }
-}
-
-static void
-stp_record_config_information(struct stp_port *p,
- const struct stp_config_bpdu *config)
-{
- p->designated_root = ntohll(config->root_id);
- p->designated_cost = ntohl(config->root_path_cost);
- p->designated_bridge = ntohll(config->bridge_id);
- p->designated_port = ntohs(config->port_id);
- stp_start_timer(&p->message_age_timer, ntohs(config->message_age));
-}
-
-static void
-stp_record_config_timeout_values(struct stp *stp,
- const struct stp_config_bpdu *config)
-{
- stp->max_age = ntohs(config->max_age);
- stp->hello_time = ntohs(config->hello_time);
- stp->forward_delay = ntohs(config->forward_delay);
- stp->topology_change = config->flags & htons(STP_CONFIG_TOPOLOGY_CHANGE);
-}
-
-static bool
-stp_is_designated_port(const struct stp_port *p)
-{
- return (p->designated_bridge == p->stp->bridge_id
- && p->designated_port == p->port_id);
-}
-
-static void
-stp_config_bpdu_generation(struct stp *stp)
-{
- struct stp_port *p;
-
- FOR_EACH_ENABLED_PORT (p, stp) {
- if (stp_is_designated_port(p)) {
- stp_transmit_config(p);
- }
- }
-}
-
-static void
-stp_transmit_tcn(struct stp *stp)
-{
- struct stp_port *p = stp->root_port;
- struct stp_tcn_bpdu tcn_bpdu;
- if (!p) {
- return;
- }
- tcn_bpdu.header.protocol_id = htons(STP_PROTOCOL_ID);
- tcn_bpdu.header.protocol_version = STP_PROTOCOL_VERSION;
- tcn_bpdu.header.bpdu_type = STP_TYPE_TCN;
- stp_send_bpdu(p, &tcn_bpdu, sizeof tcn_bpdu);
-}
-
-static void
-stp_configuration_update(struct stp *stp)
-{
- stp_root_selection(stp);
- stp_designated_port_selection(stp);
-}
-
-static bool
-stp_supersedes_root(const struct stp_port *root, const struct stp_port *p)
-{
- int p_cost = p->designated_cost + p->path_cost;
- int root_cost = root->designated_cost + root->path_cost;
-
- if (p->designated_root != root->designated_root) {
- return p->designated_root < root->designated_root;
- } else if (p_cost != root_cost) {
- return p_cost < root_cost;
- } else if (p->designated_bridge != root->designated_bridge) {
- return p->designated_bridge < root->designated_bridge;
- } else if (p->designated_port != root->designated_port) {
- return p->designated_port < root->designated_port;
- } else {
- return p->port_id < root->port_id;
- }
-}
-
-static void
-stp_root_selection(struct stp *stp)
-{
- struct stp_port *p, *root;
-
- root = NULL;
- FOR_EACH_ENABLED_PORT (p, stp) {
- if (stp_is_designated_port(p)
- || p->designated_root >= stp->bridge_id) {
- continue;
- }
- if (root && !stp_supersedes_root(root, p)) {
- continue;
- }
- root = p;
- }
- stp->root_port = root;
- if (!root) {
- stp->designated_root = stp->bridge_id;
- stp->root_path_cost = 0;
- } else {
- stp->designated_root = root->designated_root;
- stp->root_path_cost = root->designated_cost + root->path_cost;
- }
-}
-
-static void
-stp_designated_port_selection(struct stp *stp)
-{
- struct stp_port *p;
-
- FOR_EACH_ENABLED_PORT (p, stp) {
- if (stp_is_designated_port(p)
- || p->designated_root != stp->designated_root
- || stp->root_path_cost < p->designated_cost
- || (stp->root_path_cost == p->designated_cost
- && (stp->bridge_id < p->designated_bridge
- || (stp->bridge_id == p->designated_bridge
- && p->port_id <= p->designated_port))))
- {
- stp_become_designated_port(p);
- }
- }
-}
-
-static void
-stp_become_designated_port(struct stp_port *p)
-{
- struct stp *stp = p->stp;
- p->designated_root = stp->designated_root;
- p->designated_cost = stp->root_path_cost;
- p->designated_bridge = stp->bridge_id;
- p->designated_port = p->port_id;
-}
-
-static void
-stp_port_state_selection(struct stp *stp)
-{
- struct stp_port *p;
-
- FOR_EACH_ENABLED_PORT (p, stp) {
- if (p == stp->root_port) {
- p->config_pending = false;
- p->topology_change_ack = false;
- stp_make_forwarding(p);
- } else if (stp_is_designated_port(p)) {
- stp_stop_timer(&p->message_age_timer);
- stp_make_forwarding(p);
- } else {
- p->config_pending = false;
- p->topology_change_ack = false;
- stp_make_blocking(p);
- }
- }
-}
-
-static void
-stp_make_forwarding(struct stp_port *p)
-{
- if (p->state == STP_BLOCKING) {
- stp_set_port_state(p, STP_LISTENING);
- stp_start_timer(&p->forward_delay_timer, 0);
- }
-}
-
-static void
-stp_make_blocking(struct stp_port *p)
-{
- if (!(p->state & (STP_DISABLED | STP_BLOCKING))) {
- if (p->state & (STP_FORWARDING | STP_LEARNING)) {
- if (p->change_detection_enabled) {
- stp_topology_change_detection(p->stp);
- }
- }
- stp_set_port_state(p, STP_BLOCKING);
- stp_stop_timer(&p->forward_delay_timer);
- }
-}
-
-static void
-stp_set_port_state(struct stp_port *p, enum stp_state state)
-{
- if (state != p->state && !p->state_changed) {
- p->state_changed = true;
- if (p < p->stp->first_changed_port) {
- p->stp->first_changed_port = p;
- }
- }
- p->state = state;
-}
-
-static void
-stp_topology_change_detection(struct stp *stp)
-{
- if (stp_is_root_bridge(stp)) {
- stp->topology_change = true;
- stp_start_timer(&stp->topology_change_timer, 0);
- } else if (!stp->topology_change_detected) {
- stp_transmit_tcn(stp);
- stp_start_timer(&stp->tcn_timer, 0);
- }
- stp->topology_change_detected = true;
-}
-
-static void
-stp_topology_change_acknowledged(struct stp *stp)
-{
- stp->topology_change_detected = false;
- stp_stop_timer(&stp->tcn_timer);
-}
-
-static void
-stp_acknowledge_topology_change(struct stp_port *p)
-{
- p->topology_change_ack = true;
- stp_transmit_config(p);
-}
-
-void
-stp_received_config_bpdu(struct stp *stp, struct stp_port *p,
- const struct stp_config_bpdu *config)
-{
- if (ntohs(config->message_age) >= ntohs(config->max_age)) {
- VLOG_WARN("%s: received config BPDU with message age (%u) greater "
- "than max age (%u)",
- stp->name,
- ntohs(config->message_age), ntohs(config->max_age));
- return;
- }
- if (p->state != STP_DISABLED) {
- bool root = stp_is_root_bridge(stp);
- if (stp_supersedes_port_info(p, config)) {
- stp_record_config_information(p, config);
- stp_configuration_update(stp);
- stp_port_state_selection(stp);
- if (!stp_is_root_bridge(stp) && root) {
- stp_stop_timer(&stp->hello_timer);
- if (stp->topology_change_detected) {
- stp_stop_timer(&stp->topology_change_timer);
- stp_transmit_tcn(stp);
- stp_start_timer(&stp->tcn_timer, 0);
- }
- }
- if (p == stp->root_port) {
- stp_record_config_timeout_values(stp, config);
- stp_config_bpdu_generation(stp);
- if (config->flags & htons(STP_CONFIG_TOPOLOGY_CHANGE_ACK)) {
- stp_topology_change_acknowledged(stp);
- }
- }
- } else if (stp_is_designated_port(p)) {
- stp_transmit_config(p);
- }
- }
-}
-
-void
-stp_received_tcn_bpdu(struct stp *stp, struct stp_port *p)
-{
- if (p->state != STP_DISABLED) {
- if (stp_is_designated_port(p)) {
- stp_topology_change_detection(stp);
- stp_acknowledge_topology_change(p);
- }
- }
-}
-
-static void
-stp_hello_timer_expiry(struct stp *stp)
-{
- stp_config_bpdu_generation(stp);
- stp_start_timer(&stp->hello_timer, 0);
-}
-
-static void
-stp_message_age_timer_expiry(struct stp_port *p)
-{
- struct stp *stp = p->stp;
- bool root = stp_is_root_bridge(stp);
- stp_become_designated_port(p);
- stp_configuration_update(stp);
- stp_port_state_selection(stp);
- if (stp_is_root_bridge(stp) && !root) {
- stp->max_age = stp->bridge_max_age;
- stp->hello_time = stp->bridge_hello_time;
- stp->forward_delay = stp->bridge_forward_delay;
- stp_topology_change_detection(stp);
- stp_stop_timer(&stp->tcn_timer);
- stp_config_bpdu_generation(stp);
- stp_start_timer(&stp->hello_timer, 0);
- }
-}
-
-static bool
-stp_is_designated_for_some_port(const struct stp *stp)
-{
- const struct stp_port *p;
-
- FOR_EACH_ENABLED_PORT (p, stp) {
- if (p->designated_bridge == stp->bridge_id) {
- return true;
- }
- }
- return false;
-}
-
-static void
-stp_forward_delay_timer_expiry(struct stp_port *p)
-{
- if (p->state == STP_LISTENING) {
- stp_set_port_state(p, STP_LEARNING);
- stp_start_timer(&p->forward_delay_timer, 0);
- } else if (p->state == STP_LEARNING) {
- stp_set_port_state(p, STP_FORWARDING);
- if (stp_is_designated_for_some_port(p->stp)) {
- if (p->change_detection_enabled) {
- stp_topology_change_detection(p->stp);
- }
- }
- }
-}
-
-static void
-stp_tcn_timer_expiry(struct stp *stp)
-{
- stp_transmit_tcn(stp);
- stp_start_timer(&stp->tcn_timer, 0);
-}
-
-static void
-stp_topology_change_timer_expiry(struct stp *stp)
-{
- stp->topology_change_detected = false;
- stp->topology_change = false;
-}
-
-static void
-stp_hold_timer_expiry(struct stp_port *p)
-{
- if (p->config_pending) {
- stp_transmit_config(p);
- }
-}
-
-static void
-stp_initialize_port(struct stp_port *p, enum stp_state state)
-{
- assert(state & (STP_DISABLED | STP_BLOCKING));
- stp_become_designated_port(p);
- stp_set_port_state(p, state);
- p->topology_change_ack = false;
- p->config_pending = false;
- p->change_detection_enabled = true;
- stp_stop_timer(&p->message_age_timer);
- stp_stop_timer(&p->forward_delay_timer);
- stp_stop_timer(&p->hold_timer);
-}
-
-static void
-stp_become_root_bridge(struct stp *stp)
-{
- stp->max_age = stp->bridge_max_age;
- stp->hello_time = stp->bridge_hello_time;
- stp->forward_delay = stp->bridge_forward_delay;
- stp_topology_change_detection(stp);
- stp_stop_timer(&stp->tcn_timer);
- stp_config_bpdu_generation(stp);
- stp_start_timer(&stp->hello_timer, 0);
-}
-
-static void
-stp_start_timer(struct stp_timer *timer, int value)
-{
- timer->value = value;
- timer->active = true;
-}
-
-static void
-stp_stop_timer(struct stp_timer *timer)
-{
- timer->active = false;
-}
-
-static bool
-stp_timer_expired(struct stp_timer *timer, int elapsed, int timeout)
-{
- if (timer->active) {
- timer->value += elapsed;
- if (timer->value >= timeout) {
- timer->active = false;
- return true;
- }
- }
- return false;
-}
-
-/* Returns the number of whole STP timer ticks in 'ms' milliseconds. There
- * are 256 STP timer ticks per second. */
-static int
-ms_to_timer(int ms)
-{
- return ms * 0x100 / 1000;
-}
-
-/* Returns the number of leftover milliseconds when 'ms' is converted to STP
- * timer ticks. */
-static int
-ms_to_timer_remainder(int ms)
-{
- return ms * 0x100 % 1000;
-}
-
-/* Returns the number of whole milliseconds in 'timer' STP timer ticks. There
- * are 256 STP timer ticks per second. */
-static int
-timer_to_ms(int timer)
-{
- return timer * 1000 / 0x100;
-}
-
-static int
-clamp(int x, int min, int max)
-{
- return x < min ? min : x > max ? max : x;
-}
-
-static void
-stp_update_bridge_timers(struct stp *stp)
-{
- int ht, ma, fd;
-
- ht = clamp(stp->rq_hello_time, 1000, 10000);
- ma = clamp(stp->rq_max_age, MAX(2 * (ht + 1000), 6000), 40000);
- fd = clamp(stp->rq_forward_delay, ma / 2 + 1000, 30000);
-
- stp->bridge_hello_time = ms_to_timer(ht);
- stp->bridge_max_age = ms_to_timer(ma);
- stp->bridge_forward_delay = ms_to_timer(fd);
-
- if (stp_is_root_bridge(stp)) {
- stp->max_age = stp->bridge_max_age;
- stp->hello_time = stp->bridge_hello_time;
- stp->forward_delay = stp->bridge_forward_delay;
- }
-}
-
-static void
-stp_send_bpdu(struct stp_port *p, const void *bpdu, size_t bpdu_size)
-{
- struct eth_header *eth;
- struct llc_header *llc;
- struct ofpbuf *pkt;
-
- /* Skeleton. */
- pkt = ofpbuf_new(ETH_HEADER_LEN + LLC_HEADER_LEN + bpdu_size);
- pkt->l2 = eth = ofpbuf_put_zeros(pkt, sizeof *eth);
- llc = ofpbuf_put_zeros(pkt, sizeof *llc);
- pkt->l3 = ofpbuf_put(pkt, bpdu, bpdu_size);
-
- /* 802.2 header. */
- memcpy(eth->eth_dst, stp_eth_addr, ETH_ADDR_LEN);
- /* p->stp->send_bpdu() must fill in source address. */
- eth->eth_type = htons(pkt->size - ETH_HEADER_LEN);
-
- /* LLC header. */
- llc->llc_dsap = STP_LLC_DSAP;
- llc->llc_ssap = STP_LLC_SSAP;
- llc->llc_cntl = STP_LLC_CNTL;
-
- p->stp->send_bpdu(pkt, stp_port_no(p), p->stp->aux);
-}