diff options
Diffstat (limited to 'net/bridge/br_stp_bpdu.c')
| -rw-r--r-- | net/bridge/br_stp_bpdu.c | 205 |
1 files changed, 205 insertions, 0 deletions
diff --git a/net/bridge/br_stp_bpdu.c b/net/bridge/br_stp_bpdu.c new file mode 100644 index 00000000000..b91a875aca0 --- /dev/null +++ b/net/bridge/br_stp_bpdu.c @@ -0,0 +1,205 @@ +/* + * Spanning tree protocol; BPDU handling + * Linux ethernet bridge + * + * Authors: + * Lennert Buytenhek <buytenh@gnu.org> + * + * $Id: br_stp_bpdu.c,v 1.3 2001/11/10 02:35:25 davem Exp $ + * + * 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 "br_private.h" +#include "br_private_stp.h" + +#define JIFFIES_TO_TICKS(j) (((j) << 8) / HZ) +#define TICKS_TO_JIFFIES(j) (((j) * HZ) >> 8) + +static void br_send_bpdu(struct net_bridge_port *p, unsigned char *data, int length) +{ + struct net_device *dev; + struct sk_buff *skb; + int size; + + if (!p->br->stp_enabled) + return; + + size = length + 2*ETH_ALEN + 2; + if (size < 60) + size = 60; + + dev = p->dev; + + if ((skb = dev_alloc_skb(size)) == NULL) { + printk(KERN_INFO "br: memory squeeze!\n"); + return; + } + + skb->dev = dev; + skb->protocol = htons(ETH_P_802_2); + skb->mac.raw = skb_put(skb, size); + memcpy(skb->mac.raw, bridge_ula, ETH_ALEN); + memcpy(skb->mac.raw+ETH_ALEN, dev->dev_addr, ETH_ALEN); + skb->mac.raw[2*ETH_ALEN] = 0; + skb->mac.raw[2*ETH_ALEN+1] = length; + skb->nh.raw = skb->mac.raw + 2*ETH_ALEN + 2; + memcpy(skb->nh.raw, data, length); + memset(skb->nh.raw + length, 0xa5, size - length - 2*ETH_ALEN - 2); + + NF_HOOK(PF_BRIDGE, NF_BR_LOCAL_OUT, skb, NULL, skb->dev, + dev_queue_xmit); +} + +static __inline__ void br_set_ticks(unsigned char *dest, int jiff) +{ + __u16 ticks; + + ticks = JIFFIES_TO_TICKS(jiff); + dest[0] = (ticks >> 8) & 0xFF; + dest[1] = ticks & 0xFF; +} + +static __inline__ int br_get_ticks(unsigned char *dest) +{ + return TICKS_TO_JIFFIES((dest[0] << 8) | dest[1]); +} + +/* called under bridge lock */ +void br_send_config_bpdu(struct net_bridge_port *p, struct br_config_bpdu *bpdu) +{ + unsigned char buf[38]; + + buf[0] = 0x42; + buf[1] = 0x42; + buf[2] = 0x03; + buf[3] = 0; + buf[4] = 0; + buf[5] = 0; + buf[6] = BPDU_TYPE_CONFIG; + buf[7] = (bpdu->topology_change ? 0x01 : 0) | + (bpdu->topology_change_ack ? 0x80 : 0); + buf[8] = bpdu->root.prio[0]; + buf[9] = bpdu->root.prio[1]; + buf[10] = bpdu->root.addr[0]; + buf[11] = bpdu->root.addr[1]; + buf[12] = bpdu->root.addr[2]; + buf[13] = bpdu->root.addr[3]; + buf[14] = bpdu->root.addr[4]; + buf[15] = bpdu->root.addr[5]; + buf[16] = (bpdu->root_path_cost >> 24) & 0xFF; + buf[17] = (bpdu->root_path_cost >> 16) & 0xFF; + buf[18] = (bpdu->root_path_cost >> 8) & 0xFF; + buf[19] = bpdu->root_path_cost & 0xFF; + buf[20] = bpdu->bridge_id.prio[0]; + buf[21] = bpdu->bridge_id.prio[1]; + buf[22] = bpdu->bridge_id.addr[0]; + buf[23] = bpdu->bridge_id.addr[1]; + buf[24] = bpdu->bridge_id.addr[2]; + buf[25] = bpdu->bridge_id.addr[3]; + buf[26] = bpdu->bridge_id.addr[4]; + buf[27] = bpdu->bridge_id.addr[5]; + buf[28] = (bpdu->port_id >> 8) & 0xFF; + buf[29] = bpdu->port_id & 0xFF; + + br_set_ticks(buf+30, bpdu->message_age); + br_set_ticks(buf+32, bpdu->max_age); + br_set_ticks(buf+34, bpdu->hello_time); + br_set_ticks(buf+36, bpdu->forward_delay); + + br_send_bpdu(p, buf, 38); +} + +/* called under bridge lock */ +void br_send_tcn_bpdu(struct net_bridge_port *p) +{ + unsigned char buf[7]; + + buf[0] = 0x42; + buf[1] = 0x42; + buf[2] = 0x03; + buf[3] = 0; + buf[4] = 0; + buf[5] = 0; + buf[6] = BPDU_TYPE_TCN; + br_send_bpdu(p, buf, 7); +} + +static const unsigned char header[6] = {0x42, 0x42, 0x03, 0x00, 0x00, 0x00}; + +/* NO locks */ +int br_stp_handle_bpdu(struct sk_buff *skb) +{ + struct net_bridge_port *p = skb->dev->br_port; + struct net_bridge *br = p->br; + unsigned char *buf; + + /* need at least the 802 and STP headers */ + if (!pskb_may_pull(skb, sizeof(header)+1) || + memcmp(skb->data, header, sizeof(header))) + goto err; + + buf = skb_pull(skb, sizeof(header)); + + spin_lock_bh(&br->lock); + if (p->state == BR_STATE_DISABLED + || !(br->dev->flags & IFF_UP) + || !br->stp_enabled) + goto out; + + 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); + + br_received_config_bpdu(p, &bpdu); + } + + else if (buf[0] == BPDU_TYPE_TCN) { + br_received_tcn_bpdu(p); + } + out: + spin_unlock_bh(&br->lock); + err: + kfree_skb(skb); + return 0; +} |