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351 lines
8.4 KiB
351 lines
8.4 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* Spanning tree protocol; interface code |
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* Linux ethernet bridge |
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* |
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* Authors: |
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* Lennert Buytenhek <[email protected]> |
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*/ |
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#include <linux/kernel.h> |
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#include <linux/kmod.h> |
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#include <linux/etherdevice.h> |
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#include <linux/rtnetlink.h> |
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#include <net/switchdev.h> |
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#include "br_private.h" |
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#include "br_private_stp.h" |
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/* Port id is composed of priority and port number. |
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* NB: some bits of priority are dropped to |
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* make room for more ports. |
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*/ |
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static inline port_id br_make_port_id(__u8 priority, __u16 port_no) |
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{ |
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return ((u16)priority << BR_PORT_BITS) |
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} |
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#define BR_MAX_PORT_PRIORITY ((u16)~0 >> BR_PORT_BITS) |
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/* called under bridge lock */ |
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void br_init_port(struct net_bridge_port *p) |
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{ |
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int err; |
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p->port_id = br_make_port_id(p->priority, p->port_no); |
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br_become_designated_port(p); |
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br_set_state(p, BR_STATE_BLOCKING); |
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p->topology_change_ack = 0; |
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p->config_pending = 0; |
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err = __set_ageing_time(p->dev, p->br->ageing_time); |
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if (err) |
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netdev_err(p->dev, "failed to offload ageing time\n"); |
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} |
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/* NO locks held */ |
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void br_stp_enable_bridge(struct net_bridge *br) |
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{ |
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struct net_bridge_port *p; |
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spin_lock_bh(&br->lock); |
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if (br->stp_enabled == BR_KERNEL_STP) |
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mod_timer(&br->hello_timer, jiffies + br->hello_time); |
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mod_delayed_work(system_long_wq, &br->gc_work, HZ / 10); |
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br_config_bpdu_generation(br); |
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list_for_each_entry(p, &br->port_list, list) { |
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if (netif_running(p->dev) && netif_oper_up(p->dev)) |
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br_stp_enable_port(p); |
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} |
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spin_unlock_bh(&br->lock); |
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} |
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/* NO locks held */ |
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void br_stp_disable_bridge(struct net_bridge *br) |
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{ |
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struct net_bridge_port *p; |
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spin_lock_bh(&br->lock); |
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list_for_each_entry(p, &br->port_list, list) { |
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if (p->state != BR_STATE_DISABLED) |
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br_stp_disable_port(p); |
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} |
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__br_set_topology_change(br, 0); |
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br->topology_change_detected = 0; |
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spin_unlock_bh(&br->lock); |
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del_timer_sync(&br->hello_timer); |
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del_timer_sync(&br->topology_change_timer); |
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del_timer_sync(&br->tcn_timer); |
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cancel_delayed_work_sync(&br->gc_work); |
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} |
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/* called under bridge lock */ |
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void br_stp_enable_port(struct net_bridge_port *p) |
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{ |
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br_init_port(p); |
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br_port_state_selection(p->br); |
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br_ifinfo_notify(RTM_NEWLINK, NULL, p); |
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} |
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/* called under bridge lock */ |
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void br_stp_disable_port(struct net_bridge_port *p) |
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{ |
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struct net_bridge *br = p->br; |
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int wasroot; |
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wasroot = br_is_root_bridge(br); |
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br_become_designated_port(p); |
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br_set_state(p, BR_STATE_DISABLED); |
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p->topology_change_ack = 0; |
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p->config_pending = 0; |
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br_ifinfo_notify(RTM_NEWLINK, NULL, p); |
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del_timer(&p->message_age_timer); |
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del_timer(&p->forward_delay_timer); |
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del_timer(&p->hold_timer); |
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if (!rcu_access_pointer(p->backup_port)) |
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br_fdb_delete_by_port(br, p, 0, 0); |
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br_multicast_disable_port(p); |
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br_configuration_update(br); |
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br_port_state_selection(br); |
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if (br_is_root_bridge(br) && !wasroot) |
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br_become_root_bridge(br); |
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} |
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static int br_stp_call_user(struct net_bridge *br, char *arg) |
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{ |
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char *argv[] = { BR_STP_PROG, br->dev->name, arg, NULL }; |
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char *envp[] = { NULL }; |
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int rc; |
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/* call userspace STP and report program errors */ |
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rc = call_usermodehelper(BR_STP_PROG, argv, envp, UMH_WAIT_PROC); |
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if (rc > 0) { |
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if (rc & 0xff) |
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br_debug(br, BR_STP_PROG " received signal %d\n", |
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rc & 0x7f); |
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else |
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br_debug(br, BR_STP_PROG " exited with code %d\n", |
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(rc >> 8) & 0xff); |
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} |
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return rc; |
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} |
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static void br_stp_start(struct net_bridge *br) |
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{ |
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int err = -ENOENT; |
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if (net_eq(dev_net(br->dev), &init_net)) |
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err = br_stp_call_user(br, "start"); |
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if (err && err != -ENOENT) |
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br_err(br, "failed to start userspace STP (%d)\n", err); |
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spin_lock_bh(&br->lock); |
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if (br->bridge_forward_delay < BR_MIN_FORWARD_DELAY) |
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__br_set_forward_delay(br, BR_MIN_FORWARD_DELAY); |
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else if (br->bridge_forward_delay > BR_MAX_FORWARD_DELAY) |
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__br_set_forward_delay(br, BR_MAX_FORWARD_DELAY); |
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if (!err) { |
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br->stp_enabled = BR_USER_STP; |
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br_debug(br, "userspace STP started\n"); |
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} else { |
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br->stp_enabled = BR_KERNEL_STP; |
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br_debug(br, "using kernel STP\n"); |
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/* To start timers on any ports left in blocking */ |
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if (br->dev->flags & IFF_UP) |
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mod_timer(&br->hello_timer, jiffies + br->hello_time); |
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br_port_state_selection(br); |
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} |
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spin_unlock_bh(&br->lock); |
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} |
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static void br_stp_stop(struct net_bridge *br) |
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{ |
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int err; |
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if (br->stp_enabled == BR_USER_STP) { |
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err = br_stp_call_user(br, "stop"); |
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if (err) |
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br_err(br, "failed to stop userspace STP (%d)\n", err); |
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/* To start timers on any ports left in blocking */ |
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spin_lock_bh(&br->lock); |
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br_port_state_selection(br); |
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spin_unlock_bh(&br->lock); |
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} |
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br->stp_enabled = BR_NO_STP; |
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} |
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int br_stp_set_enabled(struct net_bridge *br, unsigned long val, |
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struct netlink_ext_ack *extack) |
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{ |
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ASSERT_RTNL(); |
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if (br_mrp_enabled(br)) { |
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NL_SET_ERR_MSG_MOD(extack, |
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"STP can't be enabled if MRP is already enabled"); |
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return -EINVAL; |
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} |
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if (val) { |
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if (br->stp_enabled == BR_NO_STP) |
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br_stp_start(br); |
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} else { |
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if (br->stp_enabled != BR_NO_STP) |
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br_stp_stop(br); |
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} |
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return 0; |
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} |
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/* called under bridge lock */ |
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void br_stp_change_bridge_id(struct net_bridge *br, const unsigned char *addr) |
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{ |
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/* should be aligned on 2 bytes for ether_addr_equal() */ |
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unsigned short oldaddr_aligned[ETH_ALEN >> 1]; |
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unsigned char *oldaddr = (unsigned char *)oldaddr_aligned; |
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struct net_bridge_port *p; |
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int wasroot; |
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wasroot = br_is_root_bridge(br); |
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br_fdb_change_mac_address(br, addr); |
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memcpy(oldaddr, br->bridge_id.addr, ETH_ALEN); |
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memcpy(br->bridge_id.addr, addr, ETH_ALEN); |
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eth_hw_addr_set(br->dev, addr); |
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list_for_each_entry(p, &br->port_list, list) { |
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if (ether_addr_equal(p->designated_bridge.addr, oldaddr)) |
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memcpy(p->designated_bridge.addr, addr, ETH_ALEN); |
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if (ether_addr_equal(p->designated_root.addr, oldaddr)) |
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memcpy(p->designated_root.addr, addr, ETH_ALEN); |
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} |
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br_configuration_update(br); |
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br_port_state_selection(br); |
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if (br_is_root_bridge(br) && !wasroot) |
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br_become_root_bridge(br); |
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} |
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/* should be aligned on 2 bytes for ether_addr_equal() */ |
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static const unsigned short br_mac_zero_aligned[ETH_ALEN >> 1]; |
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/* called under bridge lock */ |
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bool br_stp_recalculate_bridge_id(struct net_bridge *br) |
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{ |
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const unsigned char *br_mac_zero = |
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(const unsigned char *)br_mac_zero_aligned; |
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const unsigned char *addr = br_mac_zero; |
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struct net_bridge_port *p; |
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/* user has chosen a value so keep it */ |
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if (br->dev->addr_assign_type == NET_ADDR_SET) |
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return false; |
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list_for_each_entry(p, &br->port_list, list) { |
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if (addr == br_mac_zero || |
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memcmp(p->dev->dev_addr, addr, ETH_ALEN) < 0) |
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addr = p->dev->dev_addr; |
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} |
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if (ether_addr_equal(br->bridge_id.addr, addr)) |
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return false; /* no change */ |
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br_stp_change_bridge_id(br, addr); |
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return true; |
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} |
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/* Acquires and releases bridge lock */ |
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void br_stp_set_bridge_priority(struct net_bridge *br, u16 newprio) |
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{ |
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struct net_bridge_port *p; |
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int wasroot; |
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spin_lock_bh(&br->lock); |
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wasroot = br_is_root_bridge(br); |
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list_for_each_entry(p, &br->port_list, list) { |
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if (p->state != BR_STATE_DISABLED && |
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br_is_designated_port(p)) { |
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p->designated_bridge.prio[0] = (newprio >> 8) & 0xFF; |
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p->designated_bridge.prio[1] = newprio & 0xFF; |
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} |
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} |
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br->bridge_id.prio[0] = (newprio >> 8) & 0xFF; |
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br->bridge_id.prio[1] = newprio & 0xFF; |
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br_configuration_update(br); |
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br_port_state_selection(br); |
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if (br_is_root_bridge(br) && !wasroot) |
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br_become_root_bridge(br); |
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spin_unlock_bh(&br->lock); |
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} |
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/* called under bridge lock */ |
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int br_stp_set_port_priority(struct net_bridge_port *p, unsigned long newprio) |
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{ |
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port_id new_port_id; |
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if (newprio > BR_MAX_PORT_PRIORITY) |
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return -ERANGE; |
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new_port_id = br_make_port_id(newprio, p->port_no); |
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if (br_is_designated_port(p)) |
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p->designated_port = new_port_id; |
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p->port_id = new_port_id; |
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p->priority = newprio; |
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if (!memcmp(&p->br->bridge_id, &p->designated_bridge, 8) && |
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p->port_id < p->designated_port) { |
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br_become_designated_port(p); |
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br_port_state_selection(p->br); |
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} |
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return 0; |
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} |
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/* called under bridge lock */ |
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int br_stp_set_path_cost(struct net_bridge_port *p, unsigned long path_cost) |
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{ |
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if (path_cost < BR_MIN_PATH_COST || |
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path_cost > BR_MAX_PATH_COST) |
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return -ERANGE; |
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p->flags |= BR_ADMIN_COST; |
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p->path_cost = path_cost; |
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br_configuration_update(p->br); |
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br_port_state_selection(p->br); |
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return 0; |
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} |
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ssize_t br_show_bridge_id(char *buf, const struct bridge_id *id) |
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{ |
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return sprintf(buf, "%.2x%.2x.%.2x%.2x%.2x%.2x%.2x%.2x\n", |
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id->prio[0], id->prio[1], |
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id->addr[0], id->addr[1], id->addr[2], |
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id->addr[3], id->addr[4], id->addr[5]); |
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}
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