| // SPDX-License-Identifier: GPL-2.0-or-later |
| /* |
| * Spanning tree protocol; generic parts |
| * Linux ethernet bridge |
| * |
| * Authors: |
| * Lennert Buytenhek <buytenh@gnu.org> |
| */ |
| #include <linux/kernel.h> |
| #include <linux/rculist.h> |
| #include <net/switchdev.h> |
| |
| #include "br_private.h" |
| #include "br_private_stp.h" |
| |
| /* since time values in bpdu are in jiffies and then scaled (1/256) |
| * before sending, make sure that is at least one STP tick. |
| */ |
| #define MESSAGE_AGE_INCR ((HZ / 256) + 1) |
| |
| static const char *const br_port_state_names[] = { |
| [BR_STATE_DISABLED] = "disabled", |
| [BR_STATE_LISTENING] = "listening", |
| [BR_STATE_LEARNING] = "learning", |
| [BR_STATE_FORWARDING] = "forwarding", |
| [BR_STATE_BLOCKING] = "blocking", |
| }; |
| |
| void br_set_state(struct net_bridge_port *p, unsigned int state) |
| { |
| struct switchdev_attr attr = { |
| .orig_dev = p->dev, |
| .id = SWITCHDEV_ATTR_ID_PORT_STP_STATE, |
| .flags = SWITCHDEV_F_DEFER, |
| .u.stp_state = state, |
| }; |
| int err; |
| |
| p->state = state; |
| err = switchdev_port_attr_set(p->dev, &attr); |
| if (err && err != -EOPNOTSUPP) |
| br_warn(p->br, "error setting offload STP state on port %u(%s)\n", |
| (unsigned int) p->port_no, p->dev->name); |
| else |
| br_info(p->br, "port %u(%s) entered %s state\n", |
| (unsigned int) p->port_no, p->dev->name, |
| br_port_state_names[p->state]); |
| |
| if (p->br->stp_enabled == BR_KERNEL_STP) { |
| switch (p->state) { |
| case BR_STATE_BLOCKING: |
| p->stp_xstats.transition_blk++; |
| break; |
| case BR_STATE_FORWARDING: |
| p->stp_xstats.transition_fwd++; |
| break; |
| } |
| } |
| } |
| |
| /* called under bridge lock */ |
| struct net_bridge_port *br_get_port(struct net_bridge *br, u16 port_no) |
| { |
| struct net_bridge_port *p; |
| |
| list_for_each_entry_rcu(p, &br->port_list, list, |
| lockdep_is_held(&br->lock)) { |
| if (p->port_no == port_no) |
| return p; |
| } |
| |
| return NULL; |
| } |
| |
| /* called under bridge lock */ |
| static int br_should_become_root_port(const struct net_bridge_port *p, |
| u16 root_port) |
| { |
| struct net_bridge *br; |
| struct net_bridge_port *rp; |
| int t; |
| |
| br = p->br; |
| if (p->state == BR_STATE_DISABLED || |
| br_is_designated_port(p)) |
| return 0; |
| |
| if (memcmp(&br->bridge_id, &p->designated_root, 8) <= 0) |
| return 0; |
| |
| if (!root_port) |
| return 1; |
| |
| rp = br_get_port(br, root_port); |
| |
| t = memcmp(&p->designated_root, &rp->designated_root, 8); |
| if (t < 0) |
| return 1; |
| else if (t > 0) |
| return 0; |
| |
| if (p->designated_cost + p->path_cost < |
| rp->designated_cost + rp->path_cost) |
| return 1; |
| else if (p->designated_cost + p->path_cost > |
| rp->designated_cost + rp->path_cost) |
| return 0; |
| |
| t = memcmp(&p->designated_bridge, &rp->designated_bridge, 8); |
| if (t < 0) |
| return 1; |
| else if (t > 0) |
| return 0; |
| |
| if (p->designated_port < rp->designated_port) |
| return 1; |
| else if (p->designated_port > rp->designated_port) |
| return 0; |
| |
| if (p->port_id < rp->port_id) |
| return 1; |
| |
| return 0; |
| } |
| |
| static void br_root_port_block(const struct net_bridge *br, |
| struct net_bridge_port *p) |
| { |
| |
| br_notice(br, "port %u(%s) tried to become root port (blocked)", |
| (unsigned int) p->port_no, p->dev->name); |
| |
| br_set_state(p, BR_STATE_LISTENING); |
| br_ifinfo_notify(RTM_NEWLINK, NULL, p); |
| |
| if (br->forward_delay > 0) |
| mod_timer(&p->forward_delay_timer, jiffies + br->forward_delay); |
| } |
| |
| /* called under bridge lock */ |
| static void br_root_selection(struct net_bridge *br) |
| { |
| struct net_bridge_port *p; |
| u16 root_port = 0; |
| |
| list_for_each_entry(p, &br->port_list, list) { |
| if (!br_should_become_root_port(p, root_port)) |
| continue; |
| |
| if (p->flags & BR_ROOT_BLOCK) |
| br_root_port_block(br, p); |
| else |
| root_port = p->port_no; |
| } |
| |
| br->root_port = root_port; |
| |
| if (!root_port) { |
| br->designated_root = br->bridge_id; |
| br->root_path_cost = 0; |
| } else { |
| p = br_get_port(br, root_port); |
| br->designated_root = p->designated_root; |
| br->root_path_cost = p->designated_cost + p->path_cost; |
| } |
| } |
| |
| /* called under bridge lock */ |
| void br_become_root_bridge(struct net_bridge *br) |
| { |
| br->max_age = br->bridge_max_age; |
| br->hello_time = br->bridge_hello_time; |
| br->forward_delay = br->bridge_forward_delay; |
| br_topology_change_detection(br); |
| del_timer(&br->tcn_timer); |
| |
| if (br->dev->flags & IFF_UP) { |
| br_config_bpdu_generation(br); |
| mod_timer(&br->hello_timer, jiffies + br->hello_time); |
| } |
| } |
| |
| /* called under bridge lock */ |
| void br_transmit_config(struct net_bridge_port *p) |
| { |
| struct br_config_bpdu bpdu; |
| struct net_bridge *br; |
| |
| if (timer_pending(&p->hold_timer)) { |
| p->config_pending = 1; |
| return; |
| } |
| |
| br = p->br; |
| |
| bpdu.topology_change = br->topology_change; |
| bpdu.topology_change_ack = p->topology_change_ack; |
| bpdu.root = br->designated_root; |
| bpdu.root_path_cost = br->root_path_cost; |
| bpdu.bridge_id = br->bridge_id; |
| bpdu.port_id = p->port_id; |
| if (br_is_root_bridge(br)) |
| bpdu.message_age = 0; |
| else { |
| struct net_bridge_port *root |
| = br_get_port(br, br->root_port); |
| bpdu.message_age = (jiffies - root->designated_age) |
| + MESSAGE_AGE_INCR; |
| } |
| bpdu.max_age = br->max_age; |
| bpdu.hello_time = br->hello_time; |
| bpdu.forward_delay = br->forward_delay; |
| |
| if (bpdu.message_age < br->max_age) { |
| br_send_config_bpdu(p, &bpdu); |
| p->topology_change_ack = 0; |
| p->config_pending = 0; |
| if (p->br->stp_enabled == BR_KERNEL_STP) |
| mod_timer(&p->hold_timer, |
| round_jiffies(jiffies + BR_HOLD_TIME)); |
| } |
| } |
| |
| /* called under bridge lock */ |
| static void br_record_config_information(struct net_bridge_port *p, |
| const struct br_config_bpdu *bpdu) |
| { |
| p->designated_root = bpdu->root; |
| p->designated_cost = bpdu->root_path_cost; |
| p->designated_bridge = bpdu->bridge_id; |
| p->designated_port = bpdu->port_id; |
| p->designated_age = jiffies - bpdu->message_age; |
| |
| mod_timer(&p->message_age_timer, jiffies |
| + (bpdu->max_age - bpdu->message_age)); |
| } |
| |
| /* called under bridge lock */ |
| static void br_record_config_timeout_values(struct net_bridge *br, |
| const struct br_config_bpdu *bpdu) |
| { |
| br->max_age = bpdu->max_age; |
| br->hello_time = bpdu->hello_time; |
| br->forward_delay = bpdu->forward_delay; |
| __br_set_topology_change(br, bpdu->topology_change); |
| } |
| |
| /* called under bridge lock */ |
| void br_transmit_tcn(struct net_bridge *br) |
| { |
| struct net_bridge_port *p; |
| |
| p = br_get_port(br, br->root_port); |
| if (p) |
| br_send_tcn_bpdu(p); |
| else |
| br_notice(br, "root port %u not found for topology notice\n", |
| br->root_port); |
| } |
| |
| /* called under bridge lock */ |
| static int br_should_become_designated_port(const struct net_bridge_port *p) |
| { |
| struct net_bridge *br; |
| int t; |
| |
| br = p->br; |
| if (br_is_designated_port(p)) |
| return 1; |
| |
| if (memcmp(&p->designated_root, &br->designated_root, 8)) |
| return 1; |
| |
| if (br->root_path_cost < p->designated_cost) |
| return 1; |
| else if (br->root_path_cost > p->designated_cost) |
| return 0; |
| |
| t = memcmp(&br->bridge_id, &p->designated_bridge, 8); |
| if (t < 0) |
| return 1; |
| else if (t > 0) |
| return 0; |
| |
| if (p->port_id < p->designated_port) |
| return 1; |
| |
| return 0; |
| } |
| |
| /* called under bridge lock */ |
| static void br_designated_port_selection(struct net_bridge *br) |
| { |
| struct net_bridge_port *p; |
| |
| list_for_each_entry(p, &br->port_list, list) { |
| if (p->state != BR_STATE_DISABLED && |
| br_should_become_designated_port(p)) |
| br_become_designated_port(p); |
| |
| } |
| } |
| |
| /* called under bridge lock */ |
| static int br_supersedes_port_info(const struct net_bridge_port *p, |
| const struct br_config_bpdu *bpdu) |
| { |
| int t; |
| |
| t = memcmp(&bpdu->root, &p->designated_root, 8); |
| if (t < 0) |
| return 1; |
| else if (t > 0) |
| return 0; |
| |
| if (bpdu->root_path_cost < p->designated_cost) |
| return 1; |
| else if (bpdu->root_path_cost > p->designated_cost) |
| return 0; |
| |
| t = memcmp(&bpdu->bridge_id, &p->designated_bridge, 8); |
| if (t < 0) |
| return 1; |
| else if (t > 0) |
| return 0; |
| |
| if (memcmp(&bpdu->bridge_id, &p->br->bridge_id, 8)) |
| return 1; |
| |
| if (bpdu->port_id <= p->designated_port) |
| return 1; |
| |
| return 0; |
| } |
| |
| /* called under bridge lock */ |
| static void br_topology_change_acknowledged(struct net_bridge *br) |
| { |
| br->topology_change_detected = 0; |
| del_timer(&br->tcn_timer); |
| } |
| |
| /* called under bridge lock */ |
| void br_topology_change_detection(struct net_bridge *br) |
| { |
| int isroot = br_is_root_bridge(br); |
| |
| if (br->stp_enabled != BR_KERNEL_STP) |
| return; |
| |
| br_info(br, "topology change detected, %s\n", |
| isroot ? "propagating" : "sending tcn bpdu"); |
| |
| if (isroot) { |
| __br_set_topology_change(br, 1); |
| mod_timer(&br->topology_change_timer, jiffies |
| + br->bridge_forward_delay + br->bridge_max_age); |
| } else if (!br->topology_change_detected) { |
| br_transmit_tcn(br); |
| mod_timer(&br->tcn_timer, jiffies + br->bridge_hello_time); |
| } |
| |
| br->topology_change_detected = 1; |
| } |
| |
| /* called under bridge lock */ |
| void br_config_bpdu_generation(struct net_bridge *br) |
| { |
| struct net_bridge_port *p; |
| |
| list_for_each_entry(p, &br->port_list, list) { |
| if (p->state != BR_STATE_DISABLED && |
| br_is_designated_port(p)) |
| br_transmit_config(p); |
| } |
| } |
| |
| /* called under bridge lock */ |
| static void br_reply(struct net_bridge_port *p) |
| { |
| br_transmit_config(p); |
| } |
| |
| /* called under bridge lock */ |
| void br_configuration_update(struct net_bridge *br) |
| { |
| br_root_selection(br); |
| br_designated_port_selection(br); |
| } |
| |
| /* called under bridge lock */ |
| void br_become_designated_port(struct net_bridge_port *p) |
| { |
| struct net_bridge *br; |
| |
| br = p->br; |
| p->designated_root = br->designated_root; |
| p->designated_cost = br->root_path_cost; |
| p->designated_bridge = br->bridge_id; |
| p->designated_port = p->port_id; |
| } |
| |
| |
| /* called under bridge lock */ |
| static void br_make_blocking(struct net_bridge_port *p) |
| { |
| if (p->state != BR_STATE_DISABLED && |
| p->state != BR_STATE_BLOCKING) { |
| if (p->state == BR_STATE_FORWARDING || |
| p->state == BR_STATE_LEARNING) |
| br_topology_change_detection(p->br); |
| |
| br_set_state(p, BR_STATE_BLOCKING); |
| br_ifinfo_notify(RTM_NEWLINK, NULL, p); |
| |
| del_timer(&p->forward_delay_timer); |
| } |
| } |
| |
| /* called under bridge lock */ |
| static void br_make_forwarding(struct net_bridge_port *p) |
| { |
| struct net_bridge *br = p->br; |
| |
| if (p->state != BR_STATE_BLOCKING) |
| return; |
| |
| if (br->stp_enabled == BR_NO_STP || br->forward_delay == 0) { |
| br_set_state(p, BR_STATE_FORWARDING); |
| br_topology_change_detection(br); |
| del_timer(&p->forward_delay_timer); |
| } else if (br->stp_enabled == BR_KERNEL_STP) |
| br_set_state(p, BR_STATE_LISTENING); |
| else |
| br_set_state(p, BR_STATE_LEARNING); |
| |
| br_ifinfo_notify(RTM_NEWLINK, NULL, p); |
| |
| if (br->forward_delay != 0) |
| mod_timer(&p->forward_delay_timer, jiffies + br->forward_delay); |
| } |
| |
| /* called under bridge lock */ |
| void br_port_state_selection(struct net_bridge *br) |
| { |
| struct net_bridge_port *p; |
| unsigned int liveports = 0; |
| |
| list_for_each_entry(p, &br->port_list, list) { |
| if (p->state == BR_STATE_DISABLED) |
| continue; |
| |
| /* Don't change port states if userspace is handling STP */ |
| if (br->stp_enabled != BR_USER_STP) { |
| if (p->port_no == br->root_port) { |
| p->config_pending = 0; |
| p->topology_change_ack = 0; |
| br_make_forwarding(p); |
| } else if (br_is_designated_port(p)) { |
| del_timer(&p->message_age_timer); |
| br_make_forwarding(p); |
| } else { |
| p->config_pending = 0; |
| p->topology_change_ack = 0; |
| br_make_blocking(p); |
| } |
| } |
| |
| if (p->state != BR_STATE_BLOCKING) |
| br_multicast_enable_port(p); |
| /* Multicast is not disabled for the port when it goes in |
| * blocking state because the timers will expire and stop by |
| * themselves without sending more queries. |
| */ |
| if (p->state == BR_STATE_FORWARDING) |
| ++liveports; |
| } |
| |
| if (liveports == 0) |
| netif_carrier_off(br->dev); |
| else |
| netif_carrier_on(br->dev); |
| } |
| |
| /* called under bridge lock */ |
| static void br_topology_change_acknowledge(struct net_bridge_port *p) |
| { |
| p->topology_change_ack = 1; |
| br_transmit_config(p); |
| } |
| |
| /* called under bridge lock */ |
| void br_received_config_bpdu(struct net_bridge_port *p, |
| const struct br_config_bpdu *bpdu) |
| { |
| struct net_bridge *br; |
| int was_root; |
| |
| p->stp_xstats.rx_bpdu++; |
| |
| br = p->br; |
| was_root = br_is_root_bridge(br); |
| |
| if (br_supersedes_port_info(p, bpdu)) { |
| br_record_config_information(p, bpdu); |
| br_configuration_update(br); |
| br_port_state_selection(br); |
| |
| if (!br_is_root_bridge(br) && was_root) { |
| del_timer(&br->hello_timer); |
| if (br->topology_change_detected) { |
| del_timer(&br->topology_change_timer); |
| br_transmit_tcn(br); |
| |
| mod_timer(&br->tcn_timer, |
| jiffies + br->bridge_hello_time); |
| } |
| } |
| |
| if (p->port_no == br->root_port) { |
| br_record_config_timeout_values(br, bpdu); |
| br_config_bpdu_generation(br); |
| if (bpdu->topology_change_ack) |
| br_topology_change_acknowledged(br); |
| } |
| } else if (br_is_designated_port(p)) { |
| br_reply(p); |
| } |
| } |
| |
| /* called under bridge lock */ |
| void br_received_tcn_bpdu(struct net_bridge_port *p) |
| { |
| p->stp_xstats.rx_tcn++; |
| |
| if (br_is_designated_port(p)) { |
| br_info(p->br, "port %u(%s) received tcn bpdu\n", |
| (unsigned int) p->port_no, p->dev->name); |
| |
| br_topology_change_detection(p->br); |
| br_topology_change_acknowledge(p); |
| } |
| } |
| |
| /* Change bridge STP parameter */ |
| int br_set_hello_time(struct net_bridge *br, unsigned long val) |
| { |
| unsigned long t = clock_t_to_jiffies(val); |
| |
| if (t < BR_MIN_HELLO_TIME || t > BR_MAX_HELLO_TIME) |
| return -ERANGE; |
| |
| spin_lock_bh(&br->lock); |
| br->bridge_hello_time = t; |
| if (br_is_root_bridge(br)) |
| br->hello_time = br->bridge_hello_time; |
| spin_unlock_bh(&br->lock); |
| return 0; |
| } |
| |
| int br_set_max_age(struct net_bridge *br, unsigned long val) |
| { |
| unsigned long t = clock_t_to_jiffies(val); |
| |
| if (t < BR_MIN_MAX_AGE || t > BR_MAX_MAX_AGE) |
| return -ERANGE; |
| |
| spin_lock_bh(&br->lock); |
| br->bridge_max_age = t; |
| if (br_is_root_bridge(br)) |
| br->max_age = br->bridge_max_age; |
| spin_unlock_bh(&br->lock); |
| return 0; |
| |
| } |
| |
| /* called under bridge lock */ |
| int __set_ageing_time(struct net_device *dev, unsigned long t) |
| { |
| struct switchdev_attr attr = { |
| .orig_dev = dev, |
| .id = SWITCHDEV_ATTR_ID_BRIDGE_AGEING_TIME, |
| .flags = SWITCHDEV_F_SKIP_EOPNOTSUPP | SWITCHDEV_F_DEFER, |
| .u.ageing_time = jiffies_to_clock_t(t), |
| }; |
| int err; |
| |
| err = switchdev_port_attr_set(dev, &attr); |
| if (err && err != -EOPNOTSUPP) |
| return err; |
| |
| return 0; |
| } |
| |
| /* Set time interval that dynamic forwarding entries live |
| * For pure software bridge, allow values outside the 802.1 |
| * standard specification for special cases: |
| * 0 - entry never ages (all permanant) |
| * 1 - entry disappears (no persistance) |
| * |
| * Offloaded switch entries maybe more restrictive |
| */ |
| int br_set_ageing_time(struct net_bridge *br, clock_t ageing_time) |
| { |
| unsigned long t = clock_t_to_jiffies(ageing_time); |
| int err; |
| |
| err = __set_ageing_time(br->dev, t); |
| if (err) |
| return err; |
| |
| spin_lock_bh(&br->lock); |
| br->bridge_ageing_time = t; |
| br->ageing_time = t; |
| spin_unlock_bh(&br->lock); |
| |
| mod_delayed_work(system_long_wq, &br->gc_work, 0); |
| |
| return 0; |
| } |
| |
| /* called under bridge lock */ |
| void __br_set_topology_change(struct net_bridge *br, unsigned char val) |
| { |
| unsigned long t; |
| int err; |
| |
| if (br->stp_enabled == BR_KERNEL_STP && br->topology_change != val) { |
| /* On topology change, set the bridge ageing time to twice the |
| * forward delay. Otherwise, restore its default ageing time. |
| */ |
| |
| if (val) { |
| t = 2 * br->forward_delay; |
| br_debug(br, "decreasing ageing time to %lu\n", t); |
| } else { |
| t = br->bridge_ageing_time; |
| br_debug(br, "restoring ageing time to %lu\n", t); |
| } |
| |
| err = __set_ageing_time(br->dev, t); |
| if (err) |
| br_warn(br, "error offloading ageing time\n"); |
| else |
| br->ageing_time = t; |
| } |
| |
| br->topology_change = val; |
| } |
| |
| void __br_set_forward_delay(struct net_bridge *br, unsigned long t) |
| { |
| br->bridge_forward_delay = t; |
| if (br_is_root_bridge(br)) |
| br->forward_delay = br->bridge_forward_delay; |
| } |
| |
| int br_set_forward_delay(struct net_bridge *br, unsigned long val) |
| { |
| unsigned long t = clock_t_to_jiffies(val); |
| int err = -ERANGE; |
| |
| spin_lock_bh(&br->lock); |
| if (br->stp_enabled != BR_NO_STP && |
| (t < BR_MIN_FORWARD_DELAY || t > BR_MAX_FORWARD_DELAY)) |
| goto unlock; |
| |
| __br_set_forward_delay(br, t); |
| err = 0; |
| |
| unlock: |
| spin_unlock_bh(&br->lock); |
| return err; |
| } |