net/bridge/br_stp_if.c

Source file repositories/reference/linux-study-clean/net/bridge/br_stp_if.c

File Facts

System
Linux kernel
Corpus path
net/bridge/br_stp_if.c
Extension
.c
Size
8961 bytes
Lines
357
Domain
Networking Core
Bucket
Sockets, Protocols, Packet Path, And Network Policy
Inferred role
Networking Core: implementation source
Status
source implementation candidate

Why This File Exists

Networking stack implementation surface: socket APIs, protocol dispatch, packet flow, routing, filtering, and network namespaces.

Dependency Surface

Detected Declarations

Annotated Snippet

if (br->stp_helper_active) {
			int err = br_stp_call_user(br, "stop");

			if (err)
				br_err(br, "failed to stop userspace STP (%d)\n", err);
			br->stp_helper_active = false;
		}

		/* 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 (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);
	eth_hw_addr_set(br->dev, addr);

	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;

Annotation

Implementation Notes