/* * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013 Nicira, Inc. * * 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 #include "stp.h" #include #include #include #include #include #include "byte-order.h" #include "connectivity.h" #include "ofpbuf.h" #include "packets.h" #include "seq.h" #include "unixctl.h" #include "util.h" #include "vlog.h" VLOG_DEFINE_THIS_MODULE(stp); #define STP_PROTOCOL_ID 0x0000 #define STP_PROTOCOL_VERSION 0x00 #define STP_TYPE_CONFIG 0x00 #define STP_TYPE_TCN 0x80 OVS_PACKED( struct stp_bpdu_header { ovs_be16 protocol_id; /* STP_PROTOCOL_ID. */ uint8_t protocol_version; /* STP_PROTOCOL_VERSION. */ uint8_t bpdu_type; /* One of STP_TYPE_*. */ }); 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 }; OVS_PACKED( struct stp_config_bpdu { struct stp_bpdu_header header; /* Type STP_TYPE_CONFIG. */ uint8_t flags; /* STP_CONFIG_* flags. */ ovs_be64 root_id; /* 8.5.1.1: Bridge believed to be root. */ ovs_be32 root_path_cost; /* 8.5.1.2: Cost of path to root. */ ovs_be64 bridge_id; /* 8.5.1.3: ID of transmitting bridge. */ ovs_be16 port_id; /* 8.5.1.4: Port transmitting the BPDU. */ ovs_be16 message_age; /* 8.5.1.5: Age of BPDU at tx time. */ ovs_be16 max_age; /* 8.5.1.6: Timeout for received data. */ ovs_be16 hello_time; /* 8.5.1.7: Time between BPDU generation. */ ovs_be16 forward_delay; /* 8.5.1.8: State progression delay. */ }); BUILD_ASSERT_DECL(sizeof(struct stp_config_bpdu) == 35); OVS_PACKED( struct stp_tcn_bpdu { struct stp_bpdu_header header; /* Type STP_TYPE_TCN. */ }); 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; void *aux; /* Auxiliary data the user may retrieve. */ 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. */ int tx_count; /* Number of BPDUs transmitted. */ int rx_count; /* Number of valid BPDUs received. */ int error_count; /* Number of bad BPDUs received. */ bool state_changed; }; struct stp { struct list node; /* Node in all_stps list. */ /* 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. */ bool fdb_needs_flush; /* MAC learning tables needs flushing. */ struct stp_port *first_changed_port; void (*send_bpdu)(struct ofpbuf *bpdu, int port_no, void *aux); void *aux; struct ovs_refcount ref_cnt; }; static struct ovs_mutex mutex; static struct list all_stps__ = LIST_INITIALIZER(&all_stps__); static struct list *const all_stps OVS_GUARDED_BY(mutex) = &all_stps__; #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) OVS_REQUIRES(mutex) { for (; port < &stp->ports[ARRAY_SIZE(stp->ports)]; port++) { if (port->state != STP_DISABLED) { return CONST_CAST(struct stp_port *, port); } } return NULL; } #define MESSAGE_AGE_INCREMENT 1 static void stp_transmit_config(struct stp_port *) OVS_REQUIRES(mutex); static bool stp_supersedes_port_info(const struct stp_port *, const struct stp_config_bpdu *) OVS_REQUIRES(mutex); static void stp_record_config_information(struct stp_port *, const struct stp_config_bpdu *) OVS_REQUIRES(mutex); static void stp_record_config_timeout_values(struct stp *, const struct stp_config_bpdu *) OVS_REQUIRES(mutex); static bool stp_is_designated_port(const struct stp_port *) OVS_REQUIRES(mutex); static void stp_config_bpdu_generation(struct stp *) OVS_REQUIRES(mutex); static void stp_transmit_tcn(struct stp *) OVS_REQUIRES(mutex); static void stp_configuration_update(struct stp *) OVS_REQUIRES(mutex); static bool stp_supersedes_root(const struct stp_port *root, const struct stp_port *) OVS_REQUIRES(mutex); static void stp_root_selection(struct stp *) OVS_REQUIRES(mutex); static void stp_designated_port_selection(struct stp *) OVS_REQUIRES(mutex); static void stp_become_designated_port(struct stp_port *) OVS_REQUIRES(mutex); static void stp_port_state_selection(struct stp *) OVS_REQUIRES(mutex); static void stp_make_forwarding(struct stp_port *) OVS_REQUIRES(mutex); static void stp_make_blocking(struct stp_port *) OVS_REQUIRES(mutex); static void stp_set_port_state(struct stp_port *, enum stp_state) OVS_REQUIRES(mutex); static void stp_topology_change_detection(struct stp *) OVS_REQUIRES(mutex); static void stp_topology_change_acknowledged(struct stp *) OVS_REQUIRES(mutex); static void stp_acknowledge_topology_change(struct stp_port *) OVS_REQUIRES(mutex); static void stp_received_config_bpdu(struct stp *, struct stp_port *, const struct stp_config_bpdu *) OVS_REQUIRES(mutex); static void stp_received_tcn_bpdu(struct stp *, struct stp_port *) OVS_REQUIRES(mutex); static void stp_hello_timer_expiry(struct stp *) OVS_REQUIRES(mutex); static void stp_message_age_timer_expiry(struct stp_port *) OVS_REQUIRES(mutex); static bool stp_is_designated_for_some_port(const struct stp *) OVS_REQUIRES(mutex); static void stp_forward_delay_timer_expiry(struct stp_port *) OVS_REQUIRES(mutex); static void stp_tcn_timer_expiry(struct stp *) OVS_REQUIRES(mutex); static void stp_topology_change_timer_expiry(struct stp *) OVS_REQUIRES(mutex); static void stp_hold_timer_expiry(struct stp_port *) OVS_REQUIRES(mutex); static void stp_initialize_port(struct stp_port *, enum stp_state) OVS_REQUIRES(mutex); static void stp_become_root_bridge(struct stp *) OVS_REQUIRES(mutex); static void stp_update_bridge_timers(struct stp *) OVS_REQUIRES(mutex); static int clamp(int x, int min, int max); static int ms_to_timer(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) OVS_REQUIRES(mutex); static void stp_unixctl_tcn(struct unixctl_conn *, int argc, const char *argv[], void *aux); void stp_init(void) { unixctl_command_register("stp/tcn", "[bridge]", 0, 1, stp_unixctl_tcn, NULL); } /* 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 'bpdu', * the spanning tree port number 'port_no' that should transmit the * packet, and auxiliary data to be passed to the callback in 'aux'. */ struct stp * stp_create(const char *name, stp_identifier bridge_id, void (*send_bpdu)(struct ofpbuf *bpdu, int port_no, void *aux), void *aux) { static struct ovsthread_once once = OVSTHREAD_ONCE_INITIALIZER; struct stp *stp; struct stp_port *p; if (ovsthread_once_start(&once)) { /* We need a recursive mutex because stp_send_bpdu() could loop back * into the stp module through a patch port. This happens * intentionally as part of the unit tests. Ideally we'd ditch * the call back function, but for now this is what we have. */ ovs_mutex_init_recursive(&mutex); ovsthread_once_done(&once); } ovs_mutex_lock(&mutex); 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 = STP_DEFAULT_MAX_AGE; stp->rq_hello_time = STP_DEFAULT_HELLO_TIME; stp->rq_forward_delay = STP_DEFAULT_FWD_DELAY; 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); } ovs_refcount_init(&stp->ref_cnt); list_push_back(all_stps, &stp->node); ovs_mutex_unlock(&mutex); return stp; } struct stp * stp_ref(const struct stp *stp_) { struct stp *stp = CONST_CAST(struct stp *, stp_); if (stp) { ovs_refcount_ref(&stp->ref_cnt); } return stp; } /* Destroys 'stp'. */ void stp_unref(struct stp *stp) { if (stp && ovs_refcount_unref(&stp->ref_cnt) == 1) { ovs_mutex_lock(&mutex); list_remove(&stp->node); ovs_mutex_unlock(&mutex); free(stp->name); ovs_refcount_destroy(&stp->ref_cnt); free(stp); } } /* Runs 'stp' given that 'ms' milliseconds have passed. */ void stp_tick(struct stp *stp, int ms) { struct stp_port *p; int elapsed; ovs_mutex_lock(&mutex); /* 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 - timer_to_ms(elapsed); if (!elapsed) { goto out; } 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); } } out: ovs_mutex_unlock(&mutex); } static void set_bridge_id(struct stp *stp, stp_identifier new_bridge_id) OVS_REQUIRES(mutex) { 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; ovs_mutex_lock(&mutex); set_bridge_id(stp, (stp->bridge_id & pri_bits) | (bridge_id & mac_bits)); ovs_mutex_unlock(&mutex); } void stp_set_bridge_priority(struct stp *stp, uint16_t new_priority) { const uint64_t mac_bits = (UINT64_C(1) << 48) - 1; ovs_mutex_lock(&mutex); set_bridge_id(stp, ((stp->bridge_id & mac_bits) | ((uint64_t) new_priority << 48))); ovs_mutex_unlock(&mutex); } /* 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) { ovs_mutex_lock(&mutex); stp->rq_hello_time = ms; stp_update_bridge_timers(stp); ovs_mutex_unlock(&mutex); } /* 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) { ovs_mutex_lock(&mutex); stp->rq_max_age = ms; stp_update_bridge_timers(stp); ovs_mutex_unlock(&mutex); } /* 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) { ovs_mutex_lock(&mutex); stp->rq_forward_delay = ms; stp_update_bridge_timers(stp); ovs_mutex_unlock(&mutex); } /* Returns the name given to 'stp' in the call to stp_create(). */ const char * stp_get_name(const struct stp *stp) { char *name; ovs_mutex_lock(&mutex); name = stp->name; ovs_mutex_unlock(&mutex); return name; } /* Returns the bridge ID for 'stp'. */ stp_identifier stp_get_bridge_id(const struct stp *stp) { stp_identifier bridge_id; ovs_mutex_lock(&mutex); bridge_id = stp->bridge_id; ovs_mutex_unlock(&mutex); return 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) { stp_identifier designated_root; ovs_mutex_lock(&mutex); designated_root = stp->designated_root; ovs_mutex_unlock(&mutex); return 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) { bool is_root; ovs_mutex_lock(&mutex); is_root = stp->bridge_id == stp->designated_root; ovs_mutex_unlock(&mutex); return is_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) { int cost; ovs_mutex_lock(&mutex); cost = stp->root_path_cost; ovs_mutex_unlock(&mutex); return 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) { int time; ovs_mutex_lock(&mutex); time = timer_to_ms(stp->bridge_hello_time); ovs_mutex_unlock(&mutex); return 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) { int time; ovs_mutex_lock(&mutex); time = timer_to_ms(stp->bridge_max_age); ovs_mutex_unlock(&mutex); return time; } /* 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) { int time; ovs_mutex_lock(&mutex); time = timer_to_ms(stp->bridge_forward_delay); ovs_mutex_unlock(&mutex); return time; } /* Returns true if something has happened to 'stp' which necessitates flushing * the client's MAC learning table. Calling this function resets 'stp' so that * future calls will return false until flushing is required again. */ bool stp_check_and_reset_fdb_flush(struct stp *stp) { bool needs_flush; ovs_mutex_lock(&mutex); needs_flush = stp->fdb_needs_flush; stp->fdb_needs_flush = false; ovs_mutex_unlock(&mutex); return needs_flush; } /* 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) { struct stp_port *port; ovs_mutex_lock(&mutex); ovs_assert(port_no >= 0 && port_no < ARRAY_SIZE(stp->ports)); port = &stp->ports[port_no]; ovs_mutex_unlock(&mutex); return port; } /* 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) { struct stp_port *port; ovs_mutex_lock(&mutex); port = stp->root_port; ovs_mutex_unlock(&mutex); return 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, *p; bool changed = false; ovs_mutex_lock(&mutex); end = &stp->ports[ARRAY_SIZE(stp->ports)]; 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; changed = true; goto out; } } stp->first_changed_port = end; *portp = NULL; out: ovs_mutex_unlock(&mutex); return changed; } /* 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: OVS_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; } /* Returns the name for the given 'role' (for use in debugging and log * messages). */ const char * stp_role_name(enum stp_role role) { switch (role) { case STP_ROLE_ROOT: return "root"; case STP_ROLE_DESIGNATED: return "designated"; case STP_ROLE_ALTERNATE: return "alternate"; case STP_ROLE_DISABLED: return "disabled"; default: OVS_NOT_REACHED(); } } /* 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; ovs_mutex_lock(&mutex); if (p->state == STP_DISABLED) { goto out; } if (bpdu_size < sizeof(struct stp_bpdu_header)) { VLOG_WARN("%s: received runt %"PRIuSIZE"-byte BPDU", stp->name, bpdu_size); p->error_count++; goto out; } 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)); p->error_count++; goto out; } 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 %"PRIuSIZE, stp->name, bpdu_size); p->error_count++; goto out; } 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 %"PRIuSIZE, stp->name, bpdu_size); p->error_count++; goto out; } stp_received_tcn_bpdu(stp, p); break; default: VLOG_WARN("%s: received BPDU of unexpected type %"PRIu8, stp->name, header->bpdu_type); p->error_count++; goto out; } p->rx_count++; out: ovs_mutex_unlock(&mutex); } /* Returns the STP entity in which 'p' is nested. */ struct stp * stp_port_get_stp(struct stp_port *p) { struct stp *stp; ovs_mutex_lock(&mutex); stp = p->stp; ovs_mutex_unlock(&mutex); return stp; } /* Sets the 'aux' member of 'p'. * * The 'aux' member will be reset to NULL when stp_port_disable() is * called or stp_port_enable() is called when the port is in a Disabled * state. */ void stp_port_set_aux(struct stp_port *p, void *aux) { ovs_mutex_lock(&mutex); p->aux = aux; ovs_mutex_unlock(&mutex); } /* Returns the 'aux' member of 'p'. */ void * stp_port_get_aux(struct stp_port *p) { void *aux; ovs_mutex_lock(&mutex); aux = p->aux; ovs_mutex_unlock(&mutex); return aux; } /* Returns the index of port 'p' within its bridge. */ int stp_port_no(const struct stp_port *p) { struct stp *stp; int index; ovs_mutex_lock(&mutex); stp = p->stp; ovs_assert(p >= stp->ports && p < &stp->ports[ARRAY_SIZE(stp->ports)]); index = p - p->stp->ports; ovs_mutex_unlock(&mutex); return index; } /* Returns the port ID for 'p'. */ int stp_port_get_id(const struct stp_port *p) { int port_id; ovs_mutex_lock(&mutex); port_id = p->port_id; ovs_mutex_unlock(&mutex); return port_id; } /* Returns the state of port 'p'. */ enum stp_state stp_port_get_state(const struct stp_port *p) { enum stp_state state; ovs_mutex_lock(&mutex); state = p->state; ovs_mutex_unlock(&mutex); return state; } /* Returns the role of port 'p'. */ enum stp_role stp_port_get_role(const struct stp_port *p) { struct stp_port *root_port; enum stp_role role; ovs_mutex_lock(&mutex); root_port = p->stp->root_port; if (root_port && root_port->port_id == p->port_id) { role = STP_ROLE_ROOT; } else if (stp_is_designated_port(p)) { role = STP_ROLE_DESIGNATED; } else if (p->state == STP_DISABLED) { role = STP_ROLE_DISABLED; } else { role = STP_ROLE_ALTERNATE; } ovs_mutex_unlock(&mutex); return role; } /* Retrieves BPDU transmit and receive counts for 'p'. */ void stp_port_get_counts(const struct stp_port *p, int *tx_count, int *rx_count, int *error_count) { ovs_mutex_lock(&mutex); *tx_count = p->tx_count; *rx_count = p->rx_count; *error_count = p->error_count; ovs_mutex_unlock(&mutex); } /* Disables STP on port 'p'. */ void stp_port_disable(struct stp_port *p) { struct stp *stp; ovs_mutex_lock(&mutex); 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); } p->aux = NULL; } ovs_mutex_unlock(&mutex); } /* Enables STP on port 'p'. The port will initially be in "blocking" state. */ void stp_port_enable(struct stp_port *p) { ovs_mutex_lock(&mutex); if (p->state == STP_DISABLED) { stp_initialize_port(p, STP_BLOCKING); stp_port_state_selection(p->stp); } ovs_mutex_unlock(&mutex); } /* 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; ovs_mutex_lock(&mutex); 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); } } ovs_mutex_unlock(&mutex); } /* Convert 'speed' (measured in Mb/s) into the path cost. */ uint16_t stp_convert_speed_to_cost(unsigned int speed) { uint16_t ret; ovs_mutex_lock(&mutex); ret = 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). */ ovs_mutex_unlock(&mutex); return ret; } /* 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) { ovs_mutex_lock(&mutex); 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); } ovs_mutex_unlock(&mutex); } /* 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, stp_convert_speed_to_cost(speed)); } /* 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; } static void stp_transmit_config(struct stp_port *p) OVS_REQUIRES(mutex) { 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 |= STP_CONFIG_TOPOLOGY_CHANGE_ACK; } if (stp->topology_change) { config.flags |= 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) OVS_REQUIRES(mutex) { 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) OVS_REQUIRES(mutex) { 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) OVS_REQUIRES(mutex) { 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 & STP_CONFIG_TOPOLOGY_CHANGE; } static bool stp_is_designated_port(const struct stp_port *p) OVS_REQUIRES(mutex) { return (p->designated_bridge == p->stp->bridge_id && p->designated_port == p->port_id); } static void stp_config_bpdu_generation(struct stp *stp) OVS_REQUIRES(mutex) { 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) OVS_REQUIRES(mutex) { 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) OVS_REQUIRES(mutex) { stp_root_selection(stp); stp_designated_port_selection(stp); seq_change(connectivity_seq_get()); } static bool stp_supersedes_root(const struct stp_port *root, const struct stp_port *p) OVS_REQUIRES(mutex) { 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) OVS_REQUIRES(mutex) { 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) OVS_REQUIRES(mutex) { 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) OVS_REQUIRES(mutex) { 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) OVS_REQUIRES(mutex) { 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) OVS_REQUIRES(mutex) { 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) OVS_REQUIRES(mutex) { 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) OVS_REQUIRES(mutex) { if (state != p->state && !p->state_changed) { p->state_changed = true; if (p < p->stp->first_changed_port) { p->stp->first_changed_port = p; } seq_change(connectivity_seq_get()); } p->state = state; } static void stp_topology_change_detection(struct stp *stp) OVS_REQUIRES(mutex) { static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(1, 5); 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->fdb_needs_flush = true; stp->topology_change_detected = true; seq_change(connectivity_seq_get()); VLOG_INFO_RL(&rl, "%s: detected topology change.", stp->name); } static void stp_topology_change_acknowledged(struct stp *stp) OVS_REQUIRES(mutex) { stp->topology_change_detected = false; stp_stop_timer(&stp->tcn_timer); } static void stp_acknowledge_topology_change(struct stp_port *p) OVS_REQUIRES(mutex) { p->topology_change_ack = true; stp_transmit_config(p); } static void stp_received_config_bpdu(struct stp *stp, struct stp_port *p, const struct stp_config_bpdu *config) OVS_REQUIRES(mutex) { 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 & STP_CONFIG_TOPOLOGY_CHANGE_ACK) { stp_topology_change_acknowledged(stp); } if (config->flags & STP_CONFIG_TOPOLOGY_CHANGE) { stp->fdb_needs_flush = true; } } } else if (stp_is_designated_port(p)) { stp_transmit_config(p); } } } static void stp_received_tcn_bpdu(struct stp *stp, struct stp_port *p) OVS_REQUIRES(mutex) { 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) OVS_REQUIRES(mutex) { stp_config_bpdu_generation(stp); stp_start_timer(&stp->hello_timer, 0); } static void stp_message_age_timer_expiry(struct stp_port *p) OVS_REQUIRES(mutex) { 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) OVS_REQUIRES(mutex) { 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) OVS_REQUIRES(mutex) { 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) OVS_REQUIRES(mutex) { stp_transmit_tcn(stp); stp_start_timer(&stp->tcn_timer, 0); } static void stp_topology_change_timer_expiry(struct stp *stp) OVS_REQUIRES(mutex) { stp->topology_change_detected = false; stp->topology_change = false; } static void stp_hold_timer_expiry(struct stp_port *p) OVS_REQUIRES(mutex) { if (p->config_pending) { stp_transmit_config(p); } } static void stp_initialize_port(struct stp_port *p, enum stp_state state) OVS_REQUIRES(mutex) { ovs_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; p->aux = NULL; stp_stop_timer(&p->message_age_timer); stp_stop_timer(&p->forward_delay_timer); stp_stop_timer(&p->hold_timer); p->tx_count = p->rx_count = p->error_count = 0; } static void stp_become_root_bridge(struct stp *stp) OVS_REQUIRES(mutex) { 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) OVS_REQUIRES(mutex) { timer->value = value; timer->active = true; } static void stp_stop_timer(struct stp_timer *timer) OVS_REQUIRES(mutex) { timer->active = false; } static bool stp_timer_expired(struct stp_timer *timer, int elapsed, int timeout) OVS_REQUIRES(mutex) { 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 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) OVS_REQUIRES(mutex) { 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) OVS_REQUIRES(mutex) { 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, eth_addr_stp, 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); p->tx_count++; } /* Unixctl. */ static struct stp * stp_find(const char *name) OVS_REQUIRES(mutex) { struct stp *stp; LIST_FOR_EACH (stp, node, all_stps) { if (!strcmp(stp->name, name)) { return stp; } } return NULL; } static void stp_unixctl_tcn(struct unixctl_conn *conn, int argc, const char *argv[], void *aux OVS_UNUSED) { ovs_mutex_lock(&mutex); if (argc > 1) { struct stp *stp = stp_find(argv[1]); if (!stp) { unixctl_command_reply_error(conn, "no such stp object"); goto out; } stp_topology_change_detection(stp); } else { struct stp *stp; LIST_FOR_EACH (stp, node, all_stps) { stp_topology_change_detection(stp); } } unixctl_command_reply(conn, "OK"); out: ovs_mutex_unlock(&mutex); }