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  *      This program is free software; you can redistribute it and/or
   9  *      modify it under the terms of the GNU General Public License
  10  *      as published by the Free Software Foundation; either version
  11  *      2 of the License, or (at your option) any later version.
  12  */
  13
  14 #include <linux/kernel.h>
  15 #include <linux/etherdevice.h>
  16 #include <linux/rtnetlink.h>
  17
  18 #include "br_private.h"
  19 #include "br_private_stp.h"
  20
  21
  22 /* Port id is composed of priority and port number.
  23  * NB: least significant bits of priority are dropped to
  24  *     make room for more ports.
  25  */
  26 static inline port_id br_make_port_id(__u8 priority, __u16 port_no)
  27 {
  28         return ((u16)priority << BR_PORT_BITS)
  29                 | (port_no & ((1<<BR_PORT_BITS)-1));
  30 }
  31
  32 /* called under bridge lock */
  33 void br_init_port(struct net_bridge_port *p)
  34 {
  35         p->port_id = br_make_port_id(p->priority, p->port_no);
  36         br_become_designated_port(p);
  37         p->state = BR_STATE_BLOCKING;
  38         p->topology_change_ack = 0;
  39         p->config_pending = 0;
  40 }
  41
  42 /* called under bridge lock */
  43 void br_stp_enable_bridge(struct net_bridge *br)
  44 {
  45         struct net_bridge_port *p;
  46
  47         spin_lock_bh(&br->lock);
  48         mod_timer(&br->hello_timer, jiffies + br->hello_time);
  49         mod_timer(&br->gc_timer, jiffies + HZ/10);
  50
  51         br_config_bpdu_generation(br);
  52
  53         list_for_each_entry(p, &br->port_list, list) {
  54                 if ((p->dev->flags & IFF_UP) && netif_carrier_ok(p->dev))
  55                         br_stp_enable_port(p);
  56
  57         }
  58         spin_unlock_bh(&br->lock);
  59 }
  60
  61 /* NO locks held */
  62 void br_stp_disable_bridge(struct net_bridge *br)
  63 {
  64         struct net_bridge_port *p;
  65
  66         spin_lock_bh(&br->lock);
  67         list_for_each_entry(p, &br->port_list, list) {
  68                 if (p->state != BR_STATE_DISABLED)
  69                         br_stp_disable_port(p);
  70
  71         }
  72
  73         br->topology_change = 0;
  74         br->topology_change_detected = 0;
  75         spin_unlock_bh(&br->lock);
  76
  77         del_timer_sync(&br->hello_timer);
  78         del_timer_sync(&br->topology_change_timer);
  79         del_timer_sync(&br->tcn_timer);
  80         del_timer_sync(&br->gc_timer);
  81 }
  82
  83 /* called under bridge lock */
  84 void br_stp_enable_port(struct net_bridge_port *p)
  85 {
  86         br_init_port(p);
  87         br_port_state_selection(p->br);
  88         br_log_state(p);
  89 }
  90
  91 /* called under bridge lock */
  92 void br_stp_disable_port(struct net_bridge_port *p)
  93 {
  94         struct net_bridge *br = p->br;
  95         int wasroot;
  96
  97         br_log_state(p);
  98
  99         wasroot = br_is_root_bridge(br);
 100         br_become_designated_port(p);
 101         p->state = BR_STATE_DISABLED;
 102         p->topology_change_ack = 0;
 103         p->config_pending = 0;
 104
 105         del_timer(&p->message_age_timer);
 106         del_timer(&p->forward_delay_timer);
 107         del_timer(&p->hold_timer);
 108
 109         br_fdb_delete_by_port(br, p, 0);
 110         br_multicast_disable_port(p);
 111
 112         br_configuration_update(br);
 113
 114         br_port_state_selection(br);
 115
 116         if (br_is_root_bridge(br) && !wasroot)
 117                 br_become_root_bridge(br);
 118 }
 119
 120 static void br_stp_start(struct net_bridge *br)
 121 {
 122         int r;
 123         char *argv[] = { BR_STP_PROG, br->dev->name, "start", NULL };
 124         char *envp[] = { NULL };
 125
 126         r = call_usermodehelper(BR_STP_PROG, argv, envp, UMH_WAIT_PROC);
 127         if (r == 0) {
 128                 br->stp_enabled = BR_USER_STP;
 129                 br_debug(br, "userspace STP started\n");
 130         } else {
 131                 br->stp_enabled = BR_KERNEL_STP;
 132                 br_debug(br, "using kernel STP\n");
 133
 134                 /* To start timers on any ports left in blocking */
 135                 spin_lock_bh(&br->lock);
 136                 br_port_state_selection(br);
 137                 spin_unlock_bh(&br->lock);
 138         }
 139 }
 140
 141 static void br_stp_stop(struct net_bridge *br)
 142 {
 143         int r;
 144         char *argv[] = { BR_STP_PROG, br->dev->name, "stop", NULL };
 145         char *envp[] = { NULL };
 146
 147         if (br->stp_enabled == BR_USER_STP) {
 148                 r = call_usermodehelper(BR_STP_PROG, argv, envp, UMH_WAIT_PROC);
 149                 br_info(br, "userspace STP stopped, return code %d\n", r);
 150
 151                 /* To start timers on any ports left in blocking */
 152                 spin_lock_bh(&br->lock);
 153                 br_port_state_selection(br);
 154                 spin_unlock_bh(&br->lock);
 155         }
 156
 157         br->stp_enabled = BR_NO_STP;
 158 }
 159
 160 void br_stp_set_enabled(struct net_bridge *br, unsigned long val)
 161 {
 162         ASSERT_RTNL();
 163
 164         if (val) {
 165                 if (br->stp_enabled == BR_NO_STP)
 166                         br_stp_start(br);
 167         } else {
 168                 if (br->stp_enabled != BR_NO_STP)
 169                         br_stp_stop(br);
 170         }
 171 }
 172
 173 /* called under bridge lock */
 174 void br_stp_change_bridge_id(struct net_bridge *br, const unsigned char *addr)
 175 {
 176         /* should be aligned on 2 bytes for compare_ether_addr() */
 177         unsigned short oldaddr_aligned[ETH_ALEN >> 1];
 178         unsigned char *oldaddr = (unsigned char *)oldaddr_aligned;
 179         struct net_bridge_port *p;
 180         int wasroot;
 181
 182         wasroot = br_is_root_bridge(br);
 183
 184         memcpy(oldaddr, br->bridge_id.addr, ETH_ALEN);
 185         memcpy(br->bridge_id.addr, addr, ETH_ALEN);
 186         memcpy(br->dev->dev_addr, addr, ETH_ALEN);
 187
 188         list_for_each_entry(p, &br->port_list, list) {
 189                 if (!compare_ether_addr(p->designated_bridge.addr, oldaddr))
 190                         memcpy(p->designated_bridge.addr, addr, ETH_ALEN);
 191
 192                 if (!compare_ether_addr(p->designated_root.addr, oldaddr))
 193                         memcpy(p->designated_root.addr, addr, ETH_ALEN);
 194
 195         }
 196
 197         br_configuration_update(br);
 198         br_port_state_selection(br);
 199         if (br_is_root_bridge(br) && !wasroot)
 200                 br_become_root_bridge(br);
 201 }
 202
 203 /* should be aligned on 2 bytes for compare_ether_addr() */
 204 static const unsigned short br_mac_zero_aligned[ETH_ALEN >> 1];
 205
 206 /* called under bridge lock */
 207 bool br_stp_recalculate_bridge_id(struct net_bridge *br)
 208 {
 209         const unsigned char *br_mac_zero =
 210                         (const unsigned char *)br_mac_zero_aligned;
 211         const unsigned char *addr = br_mac_zero;
 212         struct net_bridge_port *p;
 213
 214         /* user has chosen a value so keep it */
 215         if (br->flags & BR_SET_MAC_ADDR)
 216                 return false;
 217
 218         list_for_each_entry(p, &br->port_list, list) {
 219                 if (addr == br_mac_zero ||
 220                     memcmp(p->dev->dev_addr, addr, ETH_ALEN) < 0)
 221                         addr = p->dev->dev_addr;
 222
 223         }
 224
 225         if (compare_ether_addr(br->bridge_id.addr, addr) == 0)
 226                 return false;   /* no change */
 227
 228         br_stp_change_bridge_id(br, addr);
 229         return true;
 230 }
 231
 232 /* called under bridge lock */
 233 void br_stp_set_bridge_priority(struct net_bridge *br, u16 newprio)
 234 {
 235         struct net_bridge_port *p;
 236         int wasroot;
 237
 238         wasroot = br_is_root_bridge(br);
 239
 240         list_for_each_entry(p, &br->port_list, list) {
 241                 if (p->state != BR_STATE_DISABLED &&
 242                     br_is_designated_port(p)) {
 243                         p->designated_bridge.prio[0] = (newprio >> 8) & 0xFF;
 244                         p->designated_bridge.prio[1] = newprio & 0xFF;
 245                 }
 246
 247         }
 248
 249         br->bridge_id.prio[0] = (newprio >> 8) & 0xFF;
 250         br->bridge_id.prio[1] = newprio & 0xFF;
 251         br_configuration_update(br);
 252         br_port_state_selection(br);
 253         if (br_is_root_bridge(br) && !wasroot)
 254                 br_become_root_bridge(br);
 255 }
 256
 257 /* called under bridge lock */
 258 void br_stp_set_port_priority(struct net_bridge_port *p, u8 newprio)
 259 {
 260         port_id new_port_id = br_make_port_id(newprio, p->port_no);
 261
 262         if (br_is_designated_port(p))
 263                 p->designated_port = new_port_id;
 264
 265         p->port_id = new_port_id;
 266         p->priority = newprio;
 267         if (!memcmp(&p->br->bridge_id, &p->designated_bridge, 8) &&
 268             p->port_id < p->designated_port) {
 269                 br_become_designated_port(p);
 270                 br_port_state_selection(p->br);
 271         }
 272 }
 273
 274 /* called under bridge lock */
 275 void br_stp_set_path_cost(struct net_bridge_port *p, u32 path_cost)
 276 {
 277         p->path_cost = path_cost;
 278         br_configuration_update(p->br);
 279         br_port_state_selection(p->br);
 280 }
 281
 282 ssize_t br_show_bridge_id(char *buf, const struct bridge_id *id)
 283 {
 284         return sprintf(buf, "%.2x%.2x.%.2x%.2x%.2x%.2x%.2x%.2x\n",
 285                id->prio[0], id->prio[1],
 286                id->addr[0], id->addr[1], id->addr[2],
 287                id->addr[3], id->addr[4], id->addr[5]);
 288 }