net/bridge/br_stp_if.c

   1 /*
   2  *      Spanning tree protocol; interface code
   3  *      Linux ethernet bridge
   4  *
   5  *      Authors:
   6  *      Lennert Buytenhek               <buytenh@gnu.org>
   7  *
   8  *      $Id: br_stp_if.c,v 1.4 2001/04/14 21:14:39 davem Exp $
   9  *
  10  *      This program is free software; you can redistribute it and/or
  11  *      modify it under the terms of the GNU General Public License
  12  *      as published by the Free Software Foundation; either version
  13  *      2 of the License, or (at your option) any later version.
  14  */
  15
  16 #include <linux/kernel.h>
  17 #include <linux/smp_lock.h>
  18 #include <linux/etherdevice.h>
  19 #include <linux/rtnetlink.h>
  20
  21 #include "br_private.h"
  22 #include "br_private_stp.h"
  23
  24
  25 /* Port id is composed of priority and port number.
  26  * NB: least significant bits of priority are dropped to
  27  *     make room for more ports.
  28  */
  29 static inline port_id br_make_port_id(__u8 priority, __u16 port_no)
  30 {
  31         return ((u16)priority << BR_PORT_BITS)
  32                 | (port_no & ((1<<BR_PORT_BITS)-1));
  33 }
  34
  35 /* called under bridge lock */
  36 void br_init_port(struct net_bridge_port *p)
  37 {
  38         p->port_id = br_make_port_id(p->priority, p->port_no);
  39         br_become_designated_port(p);
  40         p->state = BR_STATE_BLOCKING;
  41         p->topology_change_ack = 0;
  42         p->config_pending = 0;
  43 }
  44
  45 /* called under bridge lock */
  46 void br_stp_enable_bridge(struct net_bridge *br)
  47 {
  48         struct net_bridge_port *p;
  49
  50         spin_lock_bh(&br->lock);
  51         mod_timer(&br->hello_timer, jiffies + br->hello_time);
  52         mod_timer(&br->gc_timer, jiffies + HZ/10);
  53
  54         br_config_bpdu_generation(br);
  55
  56         list_for_each_entry(p, &br->port_list, list) {
  57                 if ((p->dev->flags & IFF_UP) && netif_carrier_ok(p->dev))
  58                         br_stp_enable_port(p);
  59
  60         }
  61         spin_unlock_bh(&br->lock);
  62 }
  63
  64 /* NO locks held */
  65 void br_stp_disable_bridge(struct net_bridge *br)
  66 {
  67         struct net_bridge_port *p;
  68
  69         spin_lock_bh(&br->lock);
  70         list_for_each_entry(p, &br->port_list, list) {
  71                 if (p->state != BR_STATE_DISABLED)
  72                         br_stp_disable_port(p);
  73
  74         }
  75
  76         br->topology_change = 0;
  77         br->topology_change_detected = 0;
  78         spin_unlock_bh(&br->lock);
  79
  80         del_timer_sync(&br->hello_timer);
  81         del_timer_sync(&br->topology_change_timer);
  82         del_timer_sync(&br->tcn_timer);
  83         del_timer_sync(&br->gc_timer);
  84 }
  85
  86 /* called under bridge lock */
  87 void br_stp_enable_port(struct net_bridge_port *p)
  88 {
  89         br_init_port(p);
  90         br_port_state_selection(p->br);
  91 }
  92
  93 /* called under bridge lock */
  94 void br_stp_disable_port(struct net_bridge_port *p)
  95 {
  96         struct net_bridge *br;
  97         int wasroot;
  98
  99         br = p->br;
 100         printk(KERN_INFO "%s: port %i(%s) entering %s state\n",
 101                br->dev->name, p->port_no, p->dev->name, "disabled");
 102
 103         wasroot = br_is_root_bridge(br);
 104         br_become_designated_port(p);
 105         p->state = BR_STATE_DISABLED;
 106         p->topology_change_ack = 0;
 107         p->config_pending = 0;
 108
 109         del_timer(&p->message_age_timer);
 110         del_timer(&p->forward_delay_timer);
 111         del_timer(&p->hold_timer);
 112
 113         br_fdb_delete_by_port(br, p, 0);
 114
 115         br_configuration_update(br);
 116
 117         br_port_state_selection(br);
 118
 119         if (br_is_root_bridge(br) && !wasroot)
 120                 br_become_root_bridge(br);
 121 }
 122
 123 static void br_stp_start(struct net_bridge *br)
 124 {
 125         int r;
 126         char *argv[] = { BR_STP_PROG, br->dev->name, "start", NULL };
 127         char *envp[] = { NULL };
 128
 129         r = call_usermodehelper(BR_STP_PROG, argv, envp, 1);
 130         if (r == 0) {
 131                 br->stp_enabled = BR_USER_STP;
 132                 printk(KERN_INFO "%s: userspace STP started\n", br->dev->name);
 133         } else {
 134                 br->stp_enabled = BR_KERNEL_STP;
 135                 printk(KERN_INFO "%s: starting userspace STP failed, "
 136                                 "staring kernel STP\n", br->dev->name);
 137
 138                 /* To start timers on any ports left in blocking */
 139                 spin_lock_bh(&br->lock);
 140                 br_port_state_selection(br);
 141                 spin_unlock_bh(&br->lock);
 142         }
 143 }
 144
 145 static void br_stp_stop(struct net_bridge *br)
 146 {
 147         int r;
 148         char *argv[] = { BR_STP_PROG, br->dev->name, "stop", NULL };
 149         char *envp[] = { NULL };
 150
 151         if (br->stp_enabled == BR_USER_STP) {
 152                 r = call_usermodehelper(BR_STP_PROG, argv, envp, 1);
 153                 printk(KERN_INFO "%s: userspace STP stopped, return code %d\n",
 154                         br->dev->name, r);
 155
 156
 157                 /* To start timers on any ports left in blocking */
 158                 spin_lock_bh(&br->lock);
 159                 br_port_state_selection(br);
 160                 spin_unlock_bh(&br->lock);
 161         }
 162
 163         br->stp_enabled = BR_NO_STP;
 164 }
 165
 166 void br_stp_set_enabled(struct net_bridge *br, unsigned long val)
 167 {
 168         ASSERT_RTNL();
 169
 170         if (val) {
 171                 if (br->stp_enabled == BR_NO_STP)
 172                         br_stp_start(br);
 173         } else {
 174                 if (br->stp_enabled != BR_NO_STP)
 175                         br_stp_stop(br);
 176         }
 177 }
 178
 179 /* called under bridge lock */
 180 void br_stp_change_bridge_id(struct net_bridge *br, const unsigned char *addr)
 181 {
 182         /* should be aligned on 2 bytes for compare_ether_addr() */
 183         unsigned short oldaddr_aligned[ETH_ALEN >> 1];
 184         unsigned char *oldaddr = (unsigned char *)oldaddr_aligned;
 185         struct net_bridge_port *p;
 186         int wasroot;
 187
 188         wasroot = br_is_root_bridge(br);
 189
 190         memcpy(oldaddr, br->bridge_id.addr, ETH_ALEN);
 191         memcpy(br->bridge_id.addr, addr, ETH_ALEN);
 192         memcpy(br->dev->dev_addr, addr, ETH_ALEN);
 193
 194         list_for_each_entry(p, &br->port_list, list) {
 195                 if (!compare_ether_addr(p->designated_bridge.addr, oldaddr))
 196                         memcpy(p->designated_bridge.addr, addr, ETH_ALEN);
 197
 198                 if (!compare_ether_addr(p->designated_root.addr, oldaddr))
 199                         memcpy(p->designated_root.addr, addr, ETH_ALEN);
 200
 201         }
 202
 203         br_configuration_update(br);
 204         br_port_state_selection(br);
 205         if (br_is_root_bridge(br) && !wasroot)
 206                 br_become_root_bridge(br);
 207 }
 208
 209 /* should be aligned on 2 bytes for compare_ether_addr() */
 210 static const unsigned short br_mac_zero_aligned[ETH_ALEN >> 1];
 211
 212 /* called under bridge lock */
 213 void br_stp_recalculate_bridge_id(struct net_bridge *br)
 214 {
 215         const unsigned char *br_mac_zero =
 216                         (const unsigned char *)br_mac_zero_aligned;
 217         const unsigned char *addr = br_mac_zero;
 218         struct net_bridge_port *p;
 219
 220         list_for_each_entry(p, &br->port_list, list) {
 221                 if (addr == br_mac_zero ||
 222                     memcmp(p->dev->dev_addr, addr, ETH_ALEN) < 0)
 223                         addr = p->dev->dev_addr;
 224
 225         }
 226
 227         if (compare_ether_addr(br->bridge_id.addr, addr))
 228                 br_stp_change_bridge_id(br, addr);
 229 }
 230
 231 /* called under bridge lock */
 232 void br_stp_set_bridge_priority(struct net_bridge *br, u16 newprio)
 233 {
 234         struct net_bridge_port *p;
 235         int wasroot;
 236
 237         wasroot = br_is_root_bridge(br);
 238
 239         list_for_each_entry(p, &br->port_list, list) {
 240                 if (p->state != BR_STATE_DISABLED &&
 241                     br_is_designated_port(p)) {
 242                         p->designated_bridge.prio[0] = (newprio >> 8) & 0xFF;
 243                         p->designated_bridge.prio[1] = newprio & 0xFF;
 244                 }
 245
 246         }
 247
 248         br->bridge_id.prio[0] = (newprio >> 8) & 0xFF;
 249         br->bridge_id.prio[1] = newprio & 0xFF;
 250         br_configuration_update(br);
 251         br_port_state_selection(br);
 252         if (br_is_root_bridge(br) && !wasroot)
 253                 br_become_root_bridge(br);
 254 }
 255
 256 /* called under bridge lock */
 257 void br_stp_set_port_priority(struct net_bridge_port *p, u8 newprio)
 258 {
 259         port_id new_port_id = br_make_port_id(newprio, p->port_no);
 260
 261         if (br_is_designated_port(p))
 262                 p->designated_port = new_port_id;
 263
 264         p->port_id = new_port_id;
 265         p->priority = newprio;
 266         if (!memcmp(&p->br->bridge_id, &p->designated_bridge, 8) &&
 267             p->port_id < p->designated_port) {
 268                 br_become_designated_port(p);
 269                 br_port_state_selection(p->br);
 270         }
 271 }
 272
 273 /* called under bridge lock */
 274 void br_stp_set_path_cost(struct net_bridge_port *p, u32 path_cost)
 275 {
 276         p->path_cost = path_cost;
 277         br_configuration_update(p->br);
 278         br_port_state_selection(p->br);
 279 }
 280
 281 ssize_t br_show_bridge_id(char *buf, const struct bridge_id *id)
 282 {
 283         return sprintf(buf, "%.2x%.2x.%.2x%.2x%.2x%.2x%.2x%.2x\n",
 284                id->prio[0], id->prio[1],
 285                id->addr[0], id->addr[1], id->addr[2],
 286                id->addr[3], id->addr[4], id->addr[5]);
 287 }