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247 lines
5.6 KiB
247 lines
5.6 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* Spanning tree protocol; BPDU handling |
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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/netfilter_bridge.h> |
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#include <linux/etherdevice.h> |
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#include <linux/llc.h> |
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#include <linux/slab.h> |
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#include <linux/pkt_sched.h> |
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#include <net/net_namespace.h> |
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#include <net/llc.h> |
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#include <net/llc_pdu.h> |
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#include <net/stp.h> |
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#include <asm/unaligned.h> |
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#include "br_private.h" |
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#include "br_private_stp.h" |
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#define STP_HZ 256 |
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#define LLC_RESERVE sizeof(struct llc_pdu_un) |
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static int br_send_bpdu_finish(struct net *net, struct sock *sk, |
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struct sk_buff *skb) |
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{ |
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return dev_queue_xmit(skb); |
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} |
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static void br_send_bpdu(struct net_bridge_port *p, |
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const unsigned char *data, int length) |
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{ |
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struct sk_buff *skb; |
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skb = dev_alloc_skb(length+LLC_RESERVE); |
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if (!skb) |
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return; |
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skb->dev = p->dev; |
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skb->protocol = htons(ETH_P_802_2); |
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skb->priority = TC_PRIO_CONTROL; |
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skb_reserve(skb, LLC_RESERVE); |
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__skb_put_data(skb, data, length); |
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llc_pdu_header_init(skb, LLC_PDU_TYPE_U, LLC_SAP_BSPAN, |
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LLC_SAP_BSPAN, LLC_PDU_CMD); |
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llc_pdu_init_as_ui_cmd(skb); |
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llc_mac_hdr_init(skb, p->dev->dev_addr, p->br->group_addr); |
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skb_reset_mac_header(skb); |
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NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_OUT, |
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dev_net(p->dev), NULL, skb, NULL, skb->dev, |
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br_send_bpdu_finish); |
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} |
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static inline void br_set_ticks(unsigned char *dest, int j) |
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{ |
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unsigned long ticks = (STP_HZ * j)/ HZ; |
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put_unaligned_be16(ticks, dest); |
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} |
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static inline int br_get_ticks(const unsigned char *src) |
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{ |
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unsigned long ticks = get_unaligned_be16(src); |
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return DIV_ROUND_UP(ticks * HZ, STP_HZ); |
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} |
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/* called under bridge lock */ |
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void br_send_config_bpdu(struct net_bridge_port *p, struct br_config_bpdu *bpdu) |
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{ |
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unsigned char buf[35]; |
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if (p->br->stp_enabled != BR_KERNEL_STP) |
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return; |
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buf[0] = 0; |
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buf[1] = 0; |
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buf[2] = 0; |
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buf[3] = BPDU_TYPE_CONFIG; |
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buf[4] = (bpdu->topology_change ? 0x01 : 0) | |
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(bpdu->topology_change_ack ? 0x80 : 0); |
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buf[5] = bpdu->root.prio[0]; |
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buf[6] = bpdu->root.prio[1]; |
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buf[7] = bpdu->root.addr[0]; |
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buf[8] = bpdu->root.addr[1]; |
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buf[9] = bpdu->root.addr[2]; |
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buf[10] = bpdu->root.addr[3]; |
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buf[11] = bpdu->root.addr[4]; |
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buf[12] = bpdu->root.addr[5]; |
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buf[13] = (bpdu->root_path_cost >> 24) & 0xFF; |
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buf[14] = (bpdu->root_path_cost >> 16) & 0xFF; |
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buf[15] = (bpdu->root_path_cost >> 8) & 0xFF; |
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buf[16] = bpdu->root_path_cost & 0xFF; |
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buf[17] = bpdu->bridge_id.prio[0]; |
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buf[18] = bpdu->bridge_id.prio[1]; |
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buf[19] = bpdu->bridge_id.addr[0]; |
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buf[20] = bpdu->bridge_id.addr[1]; |
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buf[21] = bpdu->bridge_id.addr[2]; |
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buf[22] = bpdu->bridge_id.addr[3]; |
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buf[23] = bpdu->bridge_id.addr[4]; |
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buf[24] = bpdu->bridge_id.addr[5]; |
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buf[25] = (bpdu->port_id >> 8) & 0xFF; |
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buf[26] = bpdu->port_id & 0xFF; |
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br_set_ticks(buf+27, bpdu->message_age); |
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br_set_ticks(buf+29, bpdu->max_age); |
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br_set_ticks(buf+31, bpdu->hello_time); |
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br_set_ticks(buf+33, bpdu->forward_delay); |
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br_send_bpdu(p, buf, 35); |
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p->stp_xstats.tx_bpdu++; |
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} |
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/* called under bridge lock */ |
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void br_send_tcn_bpdu(struct net_bridge_port *p) |
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{ |
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unsigned char buf[4]; |
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if (p->br->stp_enabled != BR_KERNEL_STP) |
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return; |
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buf[0] = 0; |
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buf[1] = 0; |
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buf[2] = 0; |
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buf[3] = BPDU_TYPE_TCN; |
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br_send_bpdu(p, buf, 4); |
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p->stp_xstats.tx_tcn++; |
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} |
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/* |
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* Called from llc. |
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* |
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* NO locks, but rcu_read_lock |
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*/ |
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void br_stp_rcv(const struct stp_proto *proto, struct sk_buff *skb, |
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struct net_device *dev) |
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{ |
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struct net_bridge_port *p; |
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struct net_bridge *br; |
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const unsigned char *buf; |
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if (!pskb_may_pull(skb, 4)) |
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goto err; |
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/* compare of protocol id and version */ |
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buf = skb->data; |
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if (buf[0] != 0 || buf[1] != 0 || buf[2] != 0) |
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goto err; |
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p = br_port_get_check_rcu(dev); |
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if (!p) |
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goto err; |
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br = p->br; |
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spin_lock(&br->lock); |
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if (br->stp_enabled != BR_KERNEL_STP) |
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goto out; |
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if (!(br->dev->flags & IFF_UP)) |
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goto out; |
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if (p->state == BR_STATE_DISABLED) |
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goto out; |
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if (!ether_addr_equal(eth_hdr(skb)->h_dest, br->group_addr)) |
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goto out; |
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if (p->flags & BR_BPDU_GUARD) { |
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br_notice(br, "BPDU received on blocked port %u(%s)\n", |
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(unsigned int) p->port_no, p->dev->name); |
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br_stp_disable_port(p); |
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goto out; |
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} |
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buf = skb_pull(skb, 3); |
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if (buf[0] == BPDU_TYPE_CONFIG) { |
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struct br_config_bpdu bpdu; |
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if (!pskb_may_pull(skb, 32)) |
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goto out; |
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buf = skb->data; |
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bpdu.topology_change = (buf[1] & 0x01) ? 1 : 0; |
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bpdu.topology_change_ack = (buf[1] & 0x80) ? 1 : 0; |
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bpdu.root.prio[0] = buf[2]; |
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bpdu.root.prio[1] = buf[3]; |
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bpdu.root.addr[0] = buf[4]; |
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bpdu.root.addr[1] = buf[5]; |
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bpdu.root.addr[2] = buf[6]; |
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bpdu.root.addr[3] = buf[7]; |
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bpdu.root.addr[4] = buf[8]; |
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bpdu.root.addr[5] = buf[9]; |
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bpdu.root_path_cost = |
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(buf[10] << 24) | |
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(buf[11] << 16) | |
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(buf[12] << 8) | |
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buf[13]; |
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bpdu.bridge_id.prio[0] = buf[14]; |
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bpdu.bridge_id.prio[1] = buf[15]; |
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bpdu.bridge_id.addr[0] = buf[16]; |
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bpdu.bridge_id.addr[1] = buf[17]; |
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bpdu.bridge_id.addr[2] = buf[18]; |
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bpdu.bridge_id.addr[3] = buf[19]; |
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bpdu.bridge_id.addr[4] = buf[20]; |
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bpdu.bridge_id.addr[5] = buf[21]; |
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bpdu.port_id = (buf[22] << 8) | buf[23]; |
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bpdu.message_age = br_get_ticks(buf+24); |
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bpdu.max_age = br_get_ticks(buf+26); |
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bpdu.hello_time = br_get_ticks(buf+28); |
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bpdu.forward_delay = br_get_ticks(buf+30); |
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if (bpdu.message_age > bpdu.max_age) { |
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if (net_ratelimit()) |
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br_notice(p->br, |
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"port %u config from %pM" |
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" (message_age %ul > max_age %ul)\n", |
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p->port_no, |
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eth_hdr(skb)->h_source, |
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bpdu.message_age, bpdu.max_age); |
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goto out; |
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} |
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br_received_config_bpdu(p, &bpdu); |
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} else if (buf[0] == BPDU_TYPE_TCN) { |
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br_received_tcn_bpdu(p); |
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} |
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out: |
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spin_unlock(&br->lock); |
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err: |
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kfree_skb(skb); |
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}
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