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: some 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 #define BR_MAX_PORT_PRIORITY ((u16)~0 >> BR_PORT_BITS)
  33
  34 /* called under bridge lock */
  35 void br_init_port(struct net_bridge_port *p)
  36 {
  37         p->port_id = br_make_port_id(p->priority, p->port_no);
  38         br_become_designated_port(p);
  39         p->state = BR_STATE_BLOCKING;
  40         p->topology_change_ack = 0;
  41         p->config_pending = 0;
  42 }
  43
  44 /* called under bridge lock */
  45 void br_stp_enable_bridge(struct net_bridge *br)
  46 {
  47         struct net_bridge_port *p;
  48
  49         spin_lock_bh(&br->lock);
  50         mod_timer(&br->hello_timer, jiffies + br->hello_time);
  51         mod_timer(&br->gc_timer, jiffies + HZ/10);
  52
  53         br_config_bpdu_generation(br);
  54
  55         list_for_each_entry(p, &br->port_list, list) {
  56                 if ((p->dev->flags & IFF_UP) && netif_carrier_ok(p->dev))
  57                         br_stp_enable_port(p);
  58
  59         }
  60         spin_unlock_bh(&br->lock);
  61 }
  62
  63 /* NO locks held */
  64 void br_stp_disable_bridge(struct net_bridge *br)
  65 {
  66         struct net_bridge_port *p;
  67
  68         spin_lock_bh(&br->lock);
  69         list_for_each_entry(p, &br->port_list, list) {
  70                 if (p->state != BR_STATE_DISABLED)
  71                         br_stp_disable_port(p);
  72
  73         }
  74
  75         br->topology_change = 0;
  76         br->topology_change_detected = 0;
  77         spin_unlock_bh(&br->lock);
  78
  79         del_timer_sync(&br->hello_timer);
  80         del_timer_sync(&br->topology_change_timer);
  81         del_timer_sync(&br->tcn_timer);
  82         del_timer_sync(&br->gc_timer);
  83 }
  84
  85 /* called under bridge lock */
  86 void br_stp_enable_port(struct net_bridge_port *p)
  87 {
  88         br_init_port(p);
  89         br_port_state_selection(p->br);
  90         br_log_state(p);
  91 }
  92
  93 /* called under bridge lock */
  94 void br_stp_disable_port(struct net_bridge_port *p)
  95 {
  96         struct net_bridge *br = p->br;
  97         int wasroot;
  98
  99         br_log_state(p);
 100
 101         wasroot = br_is_root_bridge(br);
 102         br_become_designated_port(p);
 103         p->state = BR_STATE_DISABLED;
 104         p->topology_change_ack = 0;
 105         p->config_pending = 0;
 106
 107         del_timer(&p->message_age_timer);
 108         del_timer(&p->forward_delay_timer);
 109         del_timer(&p->hold_timer);
 110
 111         br_fdb_delete_by_port(br, p, 0);
 112         br_multicast_disable_port(p);
 113
 114         br_configuration_update(br);
 115
 116         br_port_state_selection(br);
 117
 118         if (br_is_root_bridge(br) && !wasroot)
 119                 br_become_root_bridge(br);
 120 }
 121
 122 static void br_stp_start(struct net_bridge *br)
 123 {
 124         int r;
 125         char *argv[] = { BR_STP_PROG, br->dev->name, "start", NULL };
 126         char *envp[] = { NULL };
 127
 128         r = call_usermodehelper(BR_STP_PROG, argv, envp, UMH_WAIT_PROC);
 129         if (r == 0) {
 130                 br->stp_enabled = BR_USER_STP;
 131                 br_debug(br, "userspace STP started\n");
 132         } else {
 133                 br->stp_enabled = BR_KERNEL_STP;
 134                 br_debug(br, "using kernel STP\n");
 135
 136                 /* To start timers on any ports left in blocking */
 137                 spin_lock_bh(&br->lock);
 138                 br_port_state_selection(br);
 139                 spin_unlock_bh(&br->lock);
 140         }
 141 }
 142
 143 static void br_stp_stop(struct net_bridge *br)
 144 {
 145         int r;
 146         char *argv[] = { BR_STP_PROG, br->dev->name, "stop", NULL };
 147         char *envp[] = { NULL };
 148
 149         if (br->stp_enabled == BR_USER_STP) {
 150                 r = call_usermodehelper(BR_STP_PROG, argv, envp, UMH_WAIT_PROC);
 151                 br_info(br, "userspace STP stopped, return code %d\n", r);
 152
 153                 /* To start timers on any ports left in blocking */
 154                 spin_lock_bh(&br->lock);
 155                 br_port_state_selection(br);
 156                 spin_unlock_bh(&br->lock);
 157         }
 158
 159         br->stp_enabled = BR_NO_STP;
 160 }
 161
 162 void br_stp_set_enabled(struct net_bridge *br, unsigned long val)
 163 {
 164         ASSERT_RTNL();
 165
 166         if (val) {
 167                 if (br->stp_enabled == BR_NO_STP)
 168                         br_stp_start(br);
 169         } else {
 170                 if (br->stp_enabled != BR_NO_STP)
 171                         br_stp_stop(br);
 172         }
 173 }
 174
 175 /* called under bridge lock */
 176 void br_stp_change_bridge_id(struct net_bridge *br, const unsigned char *addr)
 177 {
 178         /* should be aligned on 2 bytes for compare_ether_addr() */
 179         unsigned short oldaddr_aligned[ETH_ALEN >> 1];
 180         unsigned char *oldaddr = (unsigned char *)oldaddr_aligned;
 181         struct net_bridge_port *p;
 182         int wasroot;
 183
 184         wasroot = br_is_root_bridge(br);
 185
 186         memcpy(oldaddr, br->bridge_id.addr, ETH_ALEN);
 187         memcpy(br->bridge_id.addr, addr, ETH_ALEN);
 188         memcpy(br->dev->dev_addr, addr, ETH_ALEN);
 189
 190         list_for_each_entry(p, &br->port_list, list) {
 191                 if (!compare_ether_addr(p->designated_bridge.addr, oldaddr))
 192                         memcpy(p->designated_bridge.addr, addr, ETH_ALEN);
 193
 194                 if (!compare_ether_addr(p->designated_root.addr, oldaddr))
 195                         memcpy(p->designated_root.addr, addr, ETH_ALEN);
 196
 197         }
 198
 199         br_configuration_update(br);
 200         br_port_state_selection(br);
 201         if (br_is_root_bridge(br) && !wasroot)
 202                 br_become_root_bridge(br);
 203 }
 204
 205 /* should be aligned on 2 bytes for compare_ether_addr() */
 206 static const unsigned short br_mac_zero_aligned[ETH_ALEN >> 1];
 207
 208 /* called under bridge lock */
 209 bool br_stp_recalculate_bridge_id(struct net_bridge *br)
 210 {
 211         const unsigned char *br_mac_zero =
 212                         (const unsigned char *)br_mac_zero_aligned;
 213         const unsigned char *addr = br_mac_zero;
 214         struct net_bridge_port *p;
 215
 216         /* user has chosen a value so keep it */
 217         if (br->flags & BR_SET_MAC_ADDR)
 218                 return false;
 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) == 0)
 228                 return false;   /* no change */
 229
 230         br_stp_change_bridge_id(br, addr);
 231         return true;
 232 }
 233
 234 /* called under bridge lock */
 235 void br_stp_set_bridge_priority(struct net_bridge *br, u16 newprio)
 236 {
 237         struct net_bridge_port *p;
 238         int wasroot;
 239
 240         wasroot = br_is_root_bridge(br);
 241
 242         list_for_each_entry(p, &br->port_list, list) {
 243                 if (p->state != BR_STATE_DISABLED &&
 244                     br_is_designated_port(p)) {
 245                         p->designated_bridge.prio[0] = (newprio >> 8) & 0xFF;
 246                         p->designated_bridge.prio[1] = newprio & 0xFF;
 247                 }
 248
 249         }
 250
 251         br->bridge_id.prio[0] = (newprio >> 8) & 0xFF;
 252         br->bridge_id.prio[1] = newprio & 0xFF;
 253         br_configuration_update(br);
 254         br_port_state_selection(br);
 255         if (br_is_root_bridge(br) && !wasroot)
 256                 br_become_root_bridge(br);
 257 }
 258
 259 /* called under bridge lock */
 260 int br_stp_set_port_priority(struct net_bridge_port *p, unsigned long newprio)
 261 {
 262         port_id new_port_id;
 263
 264         if (newprio > BR_MAX_PORT_PRIORITY)
 265                 return -ERANGE;
 266
 267         new_port_id = br_make_port_id(newprio, p->port_no);
 268         if (br_is_designated_port(p))
 269                 p->designated_port = new_port_id;
 270
 271         p->port_id = new_port_id;
 272         p->priority = newprio;
 273         if (!memcmp(&p->br->bridge_id, &p->designated_bridge, 8) &&
 274             p->port_id < p->designated_port) {
 275                 br_become_designated_port(p);
 276                 br_port_state_selection(p->br);
 277         }
 278
 279         return 0;
 280 }
 281
 282 /* called under bridge lock */
 283 int br_stp_set_path_cost(struct net_bridge_port *p, unsigned long path_cost)
 284 {
 285         if (path_cost < BR_MIN_PATH_COST ||
 286             path_cost > BR_MAX_PATH_COST)
 287                 return -ERANGE;
 288
 289         p->path_cost = path_cost;
 290         br_configuration_update(p->br);
 291         br_port_state_selection(p->br);
 292         return 0;
 293 }
 294
 295 ssize_t br_show_bridge_id(char *buf, const struct bridge_id *id)
 296 {
 297         return sprintf(buf, "%.2x%.2x.%.2x%.2x%.2x%.2x%.2x%.2x\n",
 298                id->prio[0], id->prio[1],
 299                id->addr[0], id->addr[1], id->addr[2],
 300                id->addr[3], id->addr[4], id->addr[5]);
 301 }