diff options
Diffstat (limited to '')
| -rw-r--r-- | net/bridge/br_stp_bpdu.c | 247 |
1 files changed, 247 insertions, 0 deletions
diff --git a/net/bridge/br_stp_bpdu.c b/net/bridge/br_stp_bpdu.c new file mode 100644 index 000000000..37ddcea3f --- /dev/null +++ b/net/bridge/br_stp_bpdu.c @@ -0,0 +1,247 @@ +/* + * Spanning tree protocol; BPDU handling + * Linux ethernet bridge + * + * Authors: + * Lennert Buytenhek <buytenh@gnu.org> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#include <linux/kernel.h> +#include <linux/netfilter_bridge.h> +#include <linux/etherdevice.h> +#include <linux/llc.h> +#include <linux/slab.h> +#include <linux/pkt_sched.h> +#include <net/net_namespace.h> +#include <net/llc.h> +#include <net/llc_pdu.h> +#include <net/stp.h> +#include <asm/unaligned.h> + +#include "br_private.h" +#include "br_private_stp.h" + +#define STP_HZ 256 + +#define LLC_RESERVE sizeof(struct llc_pdu_un) + +static int br_send_bpdu_finish(struct net *net, struct sock *sk, + struct sk_buff *skb) +{ + return dev_queue_xmit(skb); +} + +static void br_send_bpdu(struct net_bridge_port *p, + const unsigned char *data, int length) +{ + struct sk_buff *skb; + + skb = dev_alloc_skb(length+LLC_RESERVE); + if (!skb) + return; + + skb->dev = p->dev; + skb->protocol = htons(ETH_P_802_2); + skb->priority = TC_PRIO_CONTROL; + + skb_reserve(skb, LLC_RESERVE); + __skb_put_data(skb, data, length); + + llc_pdu_header_init(skb, LLC_PDU_TYPE_U, LLC_SAP_BSPAN, + LLC_SAP_BSPAN, LLC_PDU_CMD); + llc_pdu_init_as_ui_cmd(skb); + + llc_mac_hdr_init(skb, p->dev->dev_addr, p->br->group_addr); + + skb_reset_mac_header(skb); + + NF_HOOK(NFPROTO_BRIDGE, NF_BR_LOCAL_OUT, + dev_net(p->dev), NULL, skb, NULL, skb->dev, + br_send_bpdu_finish); +} + +static inline void br_set_ticks(unsigned char *dest, int j) +{ + unsigned long ticks = (STP_HZ * j)/ HZ; + + put_unaligned_be16(ticks, dest); +} + +static inline int br_get_ticks(const unsigned char *src) +{ + unsigned long ticks = get_unaligned_be16(src); + + return DIV_ROUND_UP(ticks * HZ, STP_HZ); +} + +/* called under bridge lock */ +void br_send_config_bpdu(struct net_bridge_port *p, struct br_config_bpdu *bpdu) +{ + unsigned char buf[35]; + + if (p->br->stp_enabled != BR_KERNEL_STP) + return; + + buf[0] = 0; + buf[1] = 0; + buf[2] = 0; + buf[3] = BPDU_TYPE_CONFIG; + buf[4] = (bpdu->topology_change ? 0x01 : 0) | + (bpdu->topology_change_ack ? 0x80 : 0); + buf[5] = bpdu->root.prio[0]; + buf[6] = bpdu->root.prio[1]; + buf[7] = bpdu->root.addr[0]; + buf[8] = bpdu->root.addr[1]; + buf[9] = bpdu->root.addr[2]; + buf[10] = bpdu->root.addr[3]; + buf[11] = bpdu->root.addr[4]; + buf[12] = bpdu->root.addr[5]; + buf[13] = (bpdu->root_path_cost >> 24) & 0xFF; + buf[14] = (bpdu->root_path_cost >> 16) & 0xFF; + buf[15] = (bpdu->root_path_cost >> 8) & 0xFF; + buf[16] = bpdu->root_path_cost & 0xFF; + buf[17] = bpdu->bridge_id.prio[0]; + buf[18] = bpdu->bridge_id.prio[1]; + buf[19] = bpdu->bridge_id.addr[0]; + buf[20] = bpdu->bridge_id.addr[1]; + buf[21] = bpdu->bridge_id.addr[2]; + buf[22] = bpdu->bridge_id.addr[3]; + buf[23] = bpdu->bridge_id.addr[4]; + buf[24] = bpdu->bridge_id.addr[5]; + buf[25] = (bpdu->port_id >> 8) & 0xFF; + buf[26] = bpdu->port_id & 0xFF; + + br_set_ticks(buf+27, bpdu->message_age); + br_set_ticks(buf+29, bpdu->max_age); + br_set_ticks(buf+31, bpdu->hello_time); + br_set_ticks(buf+33, bpdu->forward_delay); + + br_send_bpdu(p, buf, 35); +} + +/* called under bridge lock */ +void br_send_tcn_bpdu(struct net_bridge_port *p) +{ + unsigned char buf[4]; + + if (p->br->stp_enabled != BR_KERNEL_STP) + return; + + buf[0] = 0; + buf[1] = 0; + buf[2] = 0; + buf[3] = BPDU_TYPE_TCN; + br_send_bpdu(p, buf, 4); +} + +/* + * Called from llc. + * + * NO locks, but rcu_read_lock + */ +void br_stp_rcv(const struct stp_proto *proto, struct sk_buff *skb, + struct net_device *dev) +{ + struct net_bridge_port *p; + struct net_bridge *br; + const unsigned char *buf; + + if (!pskb_may_pull(skb, 4)) + goto err; + + /* compare of protocol id and version */ + buf = skb->data; + if (buf[0] != 0 || buf[1] != 0 || buf[2] != 0) + goto err; + + p = br_port_get_check_rcu(dev); + if (!p) + goto err; + + br = p->br; + spin_lock(&br->lock); + + if (br->stp_enabled != BR_KERNEL_STP) + goto out; + + if (!(br->dev->flags & IFF_UP)) + goto out; + + if (p->state == BR_STATE_DISABLED) + goto out; + + if (!ether_addr_equal(eth_hdr(skb)->h_dest, br->group_addr)) + goto out; + + if (p->flags & BR_BPDU_GUARD) { + br_notice(br, "BPDU received on blocked port %u(%s)\n", + (unsigned int) p->port_no, p->dev->name); + br_stp_disable_port(p); + goto out; + } + + buf = skb_pull(skb, 3); + + if (buf[0] == BPDU_TYPE_CONFIG) { + struct br_config_bpdu bpdu; + + if (!pskb_may_pull(skb, 32)) + goto out; + + buf = skb->data; + bpdu.topology_change = (buf[1] & 0x01) ? 1 : 0; + bpdu.topology_change_ack = (buf[1] & 0x80) ? 1 : 0; + + bpdu.root.prio[0] = buf[2]; + bpdu.root.prio[1] = buf[3]; + bpdu.root.addr[0] = buf[4]; + bpdu.root.addr[1] = buf[5]; + bpdu.root.addr[2] = buf[6]; + bpdu.root.addr[3] = buf[7]; + bpdu.root.addr[4] = buf[8]; + bpdu.root.addr[5] = buf[9]; + bpdu.root_path_cost = + (buf[10] << 24) | + (buf[11] << 16) | + (buf[12] << 8) | + buf[13]; + bpdu.bridge_id.prio[0] = buf[14]; + bpdu.bridge_id.prio[1] = buf[15]; + bpdu.bridge_id.addr[0] = buf[16]; + bpdu.bridge_id.addr[1] = buf[17]; + bpdu.bridge_id.addr[2] = buf[18]; + bpdu.bridge_id.addr[3] = buf[19]; + bpdu.bridge_id.addr[4] = buf[20]; + bpdu.bridge_id.addr[5] = buf[21]; + bpdu.port_id = (buf[22] << 8) | buf[23]; + + bpdu.message_age = br_get_ticks(buf+24); + bpdu.max_age = br_get_ticks(buf+26); + bpdu.hello_time = br_get_ticks(buf+28); + bpdu.forward_delay = br_get_ticks(buf+30); + + if (bpdu.message_age > bpdu.max_age) { + if (net_ratelimit()) + br_notice(p->br, + "port %u config from %pM" + " (message_age %ul > max_age %ul)\n", + p->port_no, + eth_hdr(skb)->h_source, + bpdu.message_age, bpdu.max_age); + goto out; + } + + br_received_config_bpdu(p, &bpdu); + } else if (buf[0] == BPDU_TYPE_TCN) { + br_received_tcn_bpdu(p); + } + out: + spin_unlock(&br->lock); + err: + kfree_skb(skb); +} |