1 files changed, 354 insertions, 0 deletions

diff --git a/net/bridge/br_stp_if.c b/net/bridge/br_stp_if.c
new file mode 100644
index 000000000..3326dfced
--- /dev/null
+++ b/net/bridge/br_stp_if.c
@@ -0,0 +1,354 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *	Spanning tree protocol; interface code
+ *	Linux ethernet bridge
+ *
+ *	Authors:
+ *	Lennert Buytenhek		<buytenh@gnu.org>
+ */
+
+#include <linux/kernel.h>
+#include <linux/kmod.h>
+#include <linux/etherdevice.h>
+#include <linux/rtnetlink.h>
+#include <net/switchdev.h>
+
+#include "br_private.h"
+#include "br_private_stp.h"
+
+
+/* Port id is composed of priority and port number.
+ * NB: some bits of priority are dropped to
+ *     make room for more ports.
+ */
+static inline port_id br_make_port_id(__u8 priority, __u16 port_no)
+{
+	return ((u16)priority << BR_PORT_BITS)
+		| (port_no & ((1<<BR_PORT_BITS)-1));
+}
+
+#define BR_MAX_PORT_PRIORITY ((u16)~0 >> BR_PORT_BITS)
+
+/* called under bridge lock */
+void br_init_port(struct net_bridge_port *p)
+{
+	int err;
+
+	p->port_id = br_make_port_id(p->priority, p->port_no);
+	br_become_designated_port(p);
+	br_set_state(p, BR_STATE_BLOCKING);
+	p->topology_change_ack = 0;
+	p->config_pending = 0;
+
+	err = __set_ageing_time(p->dev, p->br->ageing_time);
+	if (err)
+		netdev_err(p->dev, "failed to offload ageing time\n");
+}
+
+/* NO locks held */
+void br_stp_enable_bridge(struct net_bridge *br)
+{
+	struct net_bridge_port *p;
+
+	spin_lock_bh(&br->lock);
+	if (br->stp_enabled == BR_KERNEL_STP)
+		mod_timer(&br->hello_timer, jiffies + br->hello_time);
+	mod_delayed_work(system_long_wq, &br->gc_work, HZ / 10);
+
+	br_config_bpdu_generation(br);
+
+	list_for_each_entry(p, &br->port_list, list) {
+		if (netif_running(p->dev) && netif_oper_up(p->dev))
+			br_stp_enable_port(p);
+
+	}
+	spin_unlock_bh(&br->lock);
+}
+
+/* NO locks held */
+void br_stp_disable_bridge(struct net_bridge *br)
+{
+	struct net_bridge_port *p;
+
+	spin_lock_bh(&br->lock);
+	list_for_each_entry(p, &br->port_list, list) {
+		if (p->state != BR_STATE_DISABLED)
+			br_stp_disable_port(p);
+
+	}
+
+	__br_set_topology_change(br, 0);
+	br->topology_change_detected = 0;
+	spin_unlock_bh(&br->lock);
+
+	del_timer_sync(&br->hello_timer);
+	del_timer_sync(&br->topology_change_timer);
+	del_timer_sync(&br->tcn_timer);
+	cancel_delayed_work_sync(&br->gc_work);
+}
+
+/* called under bridge lock */
+void br_stp_enable_port(struct net_bridge_port *p)
+{
+	br_init_port(p);
+	br_port_state_selection(p->br);
+	br_ifinfo_notify(RTM_NEWLINK, NULL, p);
+}
+
+/* called under bridge lock */
+void br_stp_disable_port(struct net_bridge_port *p)
+{
+	struct net_bridge *br = p->br;
+	int wasroot;
+
+	wasroot = br_is_root_bridge(br);
+	br_become_designated_port(p);
+	br_set_state(p, BR_STATE_DISABLED);
+	p->topology_change_ack = 0;
+	p->config_pending = 0;
+
+	br_ifinfo_notify(RTM_NEWLINK, NULL, p);
+
+	del_timer(&p->message_age_timer);
+	del_timer(&p->forward_delay_timer);
+	del_timer(&p->hold_timer);
+
+	if (!rcu_access_pointer(p->backup_port))
+		br_fdb_delete_by_port(br, p, 0, 0);
+	br_multicast_disable_port(p);
+
+	br_configuration_update(br);
+
+	br_port_state_selection(br);
+
+	if (br_is_root_bridge(br) && !wasroot)
+		br_become_root_bridge(br);
+}
+
+static int br_stp_call_user(struct net_bridge *br, char *arg)
+{
+	char *argv[] = { BR_STP_PROG, br->dev->name, arg, NULL };
+	char *envp[] = { NULL };
+	int rc;
+
+	/* call userspace STP and report program errors */
+	rc = call_usermodehelper(BR_STP_PROG, argv, envp, UMH_WAIT_PROC);
+	if (rc > 0) {
+		if (rc & 0xff)
+			br_debug(br, BR_STP_PROG " received signal %d\n",
+				 rc & 0x7f);
+		else
+			br_debug(br, BR_STP_PROG " exited with code %d\n",
+				 (rc >> 8) & 0xff);
+	}
+
+	return rc;
+}
+
+static void br_stp_start(struct net_bridge *br)
+{
+	int err = -ENOENT;
+
+	if (net_eq(dev_net(br->dev), &init_net))
+		err = br_stp_call_user(br, "start");
+
+	if (err && err != -ENOENT)
+		br_err(br, "failed to start userspace STP (%d)\n", err);
+
+	spin_lock_bh(&br->lock);
+
+	if (br->bridge_forward_delay < BR_MIN_FORWARD_DELAY)
+		__br_set_forward_delay(br, BR_MIN_FORWARD_DELAY);
+	else if (br->bridge_forward_delay > BR_MAX_FORWARD_DELAY)
+		__br_set_forward_delay(br, BR_MAX_FORWARD_DELAY);
+
+	if (!err) {
+		br->stp_enabled = BR_USER_STP;
+		br_debug(br, "userspace STP started\n");
+	} else {
+		br->stp_enabled = BR_KERNEL_STP;
+		br_debug(br, "using kernel STP\n");
+
+		/* To start timers on any ports left in blocking */
+		if (br->dev->flags & IFF_UP)
+			mod_timer(&br->hello_timer, jiffies + br->hello_time);
+		br_port_state_selection(br);
+	}
+
+	spin_unlock_bh(&br->lock);
+}
+
+static void br_stp_stop(struct net_bridge *br)
+{
+	int err;
+
+	if (br->stp_enabled == BR_USER_STP) {
+		err = br_stp_call_user(br, "stop");
+		if (err)
+			br_err(br, "failed to stop userspace STP (%d)\n", err);
+
+		/* To start timers on any ports left in blocking */
+		spin_lock_bh(&br->lock);
+		br_port_state_selection(br);
+		spin_unlock_bh(&br->lock);
+	}
+
+	br->stp_enabled = BR_NO_STP;
+}
+
+int br_stp_set_enabled(struct net_bridge *br, unsigned long val,
+		       struct netlink_ext_ack *extack)
+{
+	ASSERT_RTNL();
+
+	if (!net_eq(dev_net(br->dev), &init_net))
+		NL_SET_ERR_MSG_MOD(extack, "STP does not work in non-root netns");
+
+	if (br_mrp_enabled(br)) {
+		NL_SET_ERR_MSG_MOD(extack,
+				   "STP can't be enabled if MRP is already enabled");
+		return -EINVAL;
+	}
+
+	if (val) {
+		if (br->stp_enabled == BR_NO_STP)
+			br_stp_start(br);
+	} else {
+		if (br->stp_enabled != BR_NO_STP)
+			br_stp_stop(br);
+	}
+
+	return 0;
+}
+
+/* called under bridge lock */
+void br_stp_change_bridge_id(struct net_bridge *br, const unsigned char *addr)
+{
+	/* should be aligned on 2 bytes for ether_addr_equal() */
+	unsigned short oldaddr_aligned[ETH_ALEN >> 1];
+	unsigned char *oldaddr = (unsigned char *)oldaddr_aligned;
+	struct net_bridge_port *p;
+	int wasroot;
+
+	wasroot = br_is_root_bridge(br);
+
+	br_fdb_change_mac_address(br, addr);
+
+	memcpy(oldaddr, br->bridge_id.addr, ETH_ALEN);
+	memcpy(br->bridge_id.addr, addr, ETH_ALEN);
+	memcpy(br->dev->dev_addr, addr, ETH_ALEN);
+
+	list_for_each_entry(p, &br->port_list, list) {
+		if (ether_addr_equal(p->designated_bridge.addr, oldaddr))
+			memcpy(p->designated_bridge.addr, addr, ETH_ALEN);
+
+		if (ether_addr_equal(p->designated_root.addr, oldaddr))
+			memcpy(p->designated_root.addr, addr, ETH_ALEN);
+	}
+
+	br_configuration_update(br);
+	br_port_state_selection(br);
+	if (br_is_root_bridge(br) && !wasroot)
+		br_become_root_bridge(br);
+}
+
+/* should be aligned on 2 bytes for ether_addr_equal() */
+static const unsigned short br_mac_zero_aligned[ETH_ALEN >> 1];
+
+/* called under bridge lock */
+bool br_stp_recalculate_bridge_id(struct net_bridge *br)
+{
+	const unsigned char *br_mac_zero =
+			(const unsigned char *)br_mac_zero_aligned;
+	const unsigned char *addr = br_mac_zero;
+	struct net_bridge_port *p;
+
+	/* user has chosen a value so keep it */
+	if (br->dev->addr_assign_type == NET_ADDR_SET)
+		return false;
+
+	list_for_each_entry(p, &br->port_list, list) {
+		if (addr == br_mac_zero ||
+		    memcmp(p->dev->dev_addr, addr, ETH_ALEN) < 0)
+			addr = p->dev->dev_addr;
+
+	}
+
+	if (ether_addr_equal(br->bridge_id.addr, addr))
+		return false;	/* no change */
+
+	br_stp_change_bridge_id(br, addr);
+	return true;
+}
+
+/* Acquires and releases bridge lock */
+void br_stp_set_bridge_priority(struct net_bridge *br, u16 newprio)
+{
+	struct net_bridge_port *p;
+	int wasroot;
+
+	spin_lock_bh(&br->lock);
+	wasroot = br_is_root_bridge(br);
+
+	list_for_each_entry(p, &br->port_list, list) {
+		if (p->state != BR_STATE_DISABLED &&
+		    br_is_designated_port(p)) {
+			p->designated_bridge.prio[0] = (newprio >> 8) & 0xFF;
+			p->designated_bridge.prio[1] = newprio & 0xFF;
+		}
+
+	}
+
+	br->bridge_id.prio[0] = (newprio >> 8) & 0xFF;
+	br->bridge_id.prio[1] = newprio & 0xFF;
+	br_configuration_update(br);
+	br_port_state_selection(br);
+	if (br_is_root_bridge(br) && !wasroot)
+		br_become_root_bridge(br);
+	spin_unlock_bh(&br->lock);
+}
+
+/* called under bridge lock */
+int br_stp_set_port_priority(struct net_bridge_port *p, unsigned long newprio)
+{
+	port_id new_port_id;
+
+	if (newprio > BR_MAX_PORT_PRIORITY)
+		return -ERANGE;
+
+	new_port_id = br_make_port_id(newprio, p->port_no);
+	if (br_is_designated_port(p))
+		p->designated_port = new_port_id;
+
+	p->port_id = new_port_id;
+	p->priority = newprio;
+	if (!memcmp(&p->br->bridge_id, &p->designated_bridge, 8) &&
+	    p->port_id < p->designated_port) {
+		br_become_designated_port(p);
+		br_port_state_selection(p->br);
+	}
+
+	return 0;
+}
+
+/* called under bridge lock */
+int br_stp_set_path_cost(struct net_bridge_port *p, unsigned long path_cost)
+{
+	if (path_cost < BR_MIN_PATH_COST ||
+	    path_cost > BR_MAX_PATH_COST)
+		return -ERANGE;
+
+	p->flags |= BR_ADMIN_COST;
+	p->path_cost = path_cost;
+	br_configuration_update(p->br);
+	br_port_state_selection(p->br);
+	return 0;
+}
+
+ssize_t br_show_bridge_id(char *buf, const struct bridge_id *id)
+{
+	return sprintf(buf, "%.2x%.2x.%.2x%.2x%.2x%.2x%.2x%.2x\n",
+	       id->prio[0], id->prio[1],
+	       id->addr[0], id->addr[1], id->addr[2],
+	       id->addr[3], id->addr[4], id->addr[5]);
+}