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 }
  89
  90 /* called under bridge lock */
  91 void br_stp_disable_port(struct net_bridge_port *p)
  92 {
  93         struct net_bridge *br;
  94         int wasroot;
  95
  96         br = p->br;
  97         printk(KERN_INFO "%s: port %i(%s) entering %s state\n",
  98                br->dev->name, p->port_no, p->dev->name, "disabled");
  99
 100         wasroot = br_is_root_bridge(br);
 101         br_become_designated_port(p);
 102         p->state = BR_STATE_DISABLED;
 103         p->topology_change_ack = 0;
 104         p->config_pending = 0;
 105
 106         del_timer(&p->message_age_timer);
 107         del_timer(&p->forward_delay_timer);
 108         del_timer(&p->hold_timer);
 109
 110         br_fdb_delete_by_port(br, p, 0);
 111         br_multicast_disable_port(p);
 112
 113         br_configuration_update(br);
 114
 115         br_port_state_selection(br);
 116
 117         if (br_is_root_bridge(br) && !wasroot)
 118                 br_become_root_bridge(br);
 119 }
 120
 121 static void br_stp_start(struct net_bridge *br)
 122 {
 123         int r;
 124         char *argv[] = { BR_STP_PROG, br->dev->name, "start", NULL };
 125         char *envp[] = { NULL };
 126
 127         r = call_usermodehelper(BR_STP_PROG, argv, envp, UMH_WAIT_PROC);
 128         if (r == 0) {
 129                 br->stp_enabled = BR_USER_STP;
 130                 printk(KERN_INFO "%s: userspace STP started\n", br->dev->name);
 131         } else {
 132                 br->stp_enabled = BR_KERNEL_STP;
 133                 printk(KERN_INFO "%s: starting userspace STP failed, "
 134                                 "starting kernel STP\n", br->dev->name);
 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, 1);
 151                 printk(KERN_INFO "%s: userspace STP stopped, return code %d\n",
 152                         br->dev->name, r);
 153
 154
 155                 /* To start timers on any ports left in blocking */
 156                 spin_lock_bh(&br->lock);
 157                 br_port_state_selection(br);
 158                 spin_unlock_bh(&br->lock);
 159         }
 160
 161         br->stp_enabled = BR_NO_STP;
 162 }
 163
 164 void br_stp_set_enabled(struct net_bridge *br, unsigned long val)
 165 {
 166         ASSERT_RTNL();
 167
 168         if (val) {
 169                 if (br->stp_enabled == BR_NO_STP)
 170                         br_stp_start(br);
 171         } else {
 172                 if (br->stp_enabled != BR_NO_STP)
 173                         br_stp_stop(br);
 174         }
 175 }
 176
 177 /* called under bridge lock */
 178 void br_stp_change_bridge_id(struct net_bridge *br, const unsigned char *addr)
 179 {
 180         /* should be aligned on 2 bytes for compare_ether_addr() */
 181         unsigned short oldaddr_aligned[ETH_ALEN >> 1];
 182         unsigned char *oldaddr = (unsigned char *)oldaddr_aligned;
 183         struct net_bridge_port *p;
 184         int wasroot;
 185
 186         wasroot = br_is_root_bridge(br);
 187
 188         memcpy(oldaddr, br->bridge_id.addr, ETH_ALEN);
 189         memcpy(br->bridge_id.addr, addr, ETH_ALEN);
 190         memcpy(br->dev->dev_addr, addr, ETH_ALEN);
 191
 192         list_for_each_entry(p, &br->port_list, list) {
 193                 if (!compare_ether_addr(p->designated_bridge.addr, oldaddr))
 194                         memcpy(p->designated_bridge.addr, addr, ETH_ALEN);
 195
 196                 if (!compare_ether_addr(p->designated_root.addr, oldaddr))
 197                         memcpy(p->designated_root.addr, addr, ETH_ALEN);
 198
 199         }
 200
 201         br_configuration_update(br);
 202         br_port_state_selection(br);
 203         if (br_is_root_bridge(br) && !wasroot)
 204                 br_become_root_bridge(br);
 205 }
 206
 207 /* should be aligned on 2 bytes for compare_ether_addr() */
 208 static const unsigned short br_mac_zero_aligned[ETH_ALEN >> 1];
 209
 210 /* called under bridge lock */
 211 void br_stp_recalculate_bridge_id(struct net_bridge *br)
 212 {
 213         const unsigned char *br_mac_zero =
 214                         (const unsigned char *)br_mac_zero_aligned;
 215         const unsigned char *addr = br_mac_zero;
 216         struct net_bridge_port *p;
 217
 218         /* user has chosen a value so keep it */
 219         if (br->flags & BR_SET_MAC_ADDR)
 220                 return;
 221
 222         list_for_each_entry(p, &br->port_list, list) {
 223                 if (addr == br_mac_zero ||
 224                     memcmp(p->dev->dev_addr, addr, ETH_ALEN) < 0)
 225                         addr = p->dev->dev_addr;
 226
 227         }
 228
 229         if (compare_ether_addr(br->bridge_id.addr, addr))
 230                 br_stp_change_bridge_id(br, addr);
 231 }
 232
 233 /* called under bridge lock */
 234 void br_stp_set_bridge_priority(struct net_bridge *br, u16 newprio)
 235 {
 236         struct net_bridge_port *p;
 237         int wasroot;
 238
 239         wasroot = br_is_root_bridge(br);
 240
 241         list_for_each_entry(p, &br->port_list, list) {
 242                 if (p->state != BR_STATE_DISABLED &&
 243                     br_is_designated_port(p)) {
 244                         p->designated_bridge.prio[0] = (newprio >> 8) & 0xFF;
 245                         p->designated_bridge.prio[1] = newprio & 0xFF;
 246                 }
 247
 248         }
 249
 250         br->bridge_id.prio[0] = (newprio >> 8) & 0xFF;
 251         br->bridge_id.prio[1] = newprio & 0xFF;
 252         br_configuration_update(br);
 253         br_port_state_selection(br);
 254         if (br_is_root_bridge(br) && !wasroot)
 255                 br_become_root_bridge(br);
 256 }
 257
 258 /* called under bridge lock */
 259 void br_stp_set_port_priority(struct net_bridge_port *p, u8 newprio)
 260 {
 261         port_id new_port_id = br_make_port_id(newprio, p->port_no);
 262
 263         if (br_is_designated_port(p))
 264                 p->designated_port = new_port_id;
 265
 266         p->port_id = new_port_id;
 267         p->priority = newprio;
 268         if (!memcmp(&p->br->bridge_id, &p->designated_bridge, 8) &&
 269             p->port_id < p->designated_port) {
 270                 br_become_designated_port(p);
 271                 br_port_state_selection(p->br);
 272         }
 273 }
 274
 275 /* called under bridge lock */
 276 void br_stp_set_path_cost(struct net_bridge_port *p, u32 path_cost)
 277 {
 278         p->path_cost = path_cost;
 279         br_configuration_update(p->br);
 280         br_port_state_selection(p->br);
 281 }
 282
 283 ssize_t br_show_bridge_id(char *buf, const struct bridge_id *id)
 284 {
 285         return sprintf(buf, "%.2x%.2x.%.2x%.2x%.2x%.2x%.2x%.2x\n",
 286                id->prio[0], id->prio[1],
 287                id->addr[0], id->addr[1], id->addr[2],
 288                id->addr[3], id->addr[4], id->addr[5]);
 289 }