net/bridge/br_fdb.c

   1 /*
   2  *      Forwarding database
   3  *      Linux ethernet bridge
   4  *
   5  *      Authors:
   6  *      Lennert Buytenhek               <buytenh@gnu.org>
   7  *
   8  *      $Id: br_fdb.c,v 1.5.2.1 2002/01/17 00:59:01 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/spinlock.h>
  18 #include <linux/if_bridge.h>
  19 #include <asm/atomic.h>
  20 #include <asm/uaccess.h>
  21 #include "br_private.h"
  22
  23 static __inline__ unsigned long __timeout(struct net_bridge *br)
  24 {
  25         unsigned long timeout;
  26
  27         timeout = jiffies - br->ageing_time;
  28         if (br->topology_change)
  29                 timeout = jiffies - br->forward_delay;
  30
  31         return timeout;
  32 }
  33
  34 static __inline__ int has_expired(struct net_bridge *br,
  35                                   struct net_bridge_fdb_entry *fdb)
  36 {
  37         if (!fdb->is_static &&
  38             time_before_eq(fdb->ageing_timer, __timeout(br)))
  39                 return 1;
  40
  41         return 0;
  42 }
  43
  44 static __inline__ void copy_fdb(struct __fdb_entry *ent, struct net_bridge_fdb_entry *f)
  45 {
  46         memset(ent, 0, sizeof(struct __fdb_entry));
  47         memcpy(ent->mac_addr, f->addr.addr, ETH_ALEN);
  48         ent->port_no = f->dst?f->dst->port_no:0;
  49         ent->is_local = f->is_local;
  50         ent->ageing_timer_value = 0;
  51         if (!f->is_static)
  52                 ent->ageing_timer_value = jiffies - f->ageing_timer;
  53 }
  54
  55 static __inline__ int br_mac_hash(unsigned char *mac)
  56 {
  57         unsigned long x;
  58
  59         x = mac[0];
  60         x = (x << 2) ^ mac[1];
  61         x = (x << 2) ^ mac[2];
  62         x = (x << 2) ^ mac[3];
  63         x = (x << 2) ^ mac[4];
  64         x = (x << 2) ^ mac[5];
  65
  66         x ^= x >> 8;
  67
  68         return x & (BR_HASH_SIZE - 1);
  69 }
  70
  71 static __inline__ void __hash_link(struct net_bridge *br,
  72                                    struct net_bridge_fdb_entry *ent,
  73                                    int hash)
  74 {
  75         ent->next_hash = br->hash[hash];
  76         if (ent->next_hash != NULL)
  77                 ent->next_hash->pprev_hash = &ent->next_hash;
  78         br->hash[hash] = ent;
  79         ent->pprev_hash = &br->hash[hash];
  80 }
  81
  82 static __inline__ void __hash_unlink(struct net_bridge_fdb_entry *ent)
  83 {
  84         *(ent->pprev_hash) = ent->next_hash;
  85         if (ent->next_hash != NULL)
  86                 ent->next_hash->pprev_hash = ent->pprev_hash;
  87         ent->next_hash = NULL;
  88         ent->pprev_hash = NULL;
  89 }
  90
  91
  92
  93 void br_fdb_changeaddr(struct net_bridge_port *p, unsigned char *newaddr)
  94 {
  95         struct net_bridge *br;
  96         int i;
  97
  98         br = p->br;
  99         write_lock_bh(&br->hash_lock);
 100         for (i=0;i<BR_HASH_SIZE;i++) {
 101                 struct net_bridge_fdb_entry *f;
 102
 103                 f = br->hash[i];
 104                 while (f != NULL) {
 105                         if (f->dst == p && f->is_local) {
 106                                 __hash_unlink(f);
 107                                 memcpy(f->addr.addr, newaddr, ETH_ALEN);
 108                                 __hash_link(br, f, br_mac_hash(newaddr));
 109                                 write_unlock_bh(&br->hash_lock);
 110                                 return;
 111                         }
 112                         f = f->next_hash;
 113                 }
 114         }
 115         write_unlock_bh(&br->hash_lock);
 116 }
 117
 118 void br_fdb_cleanup(struct net_bridge *br)
 119 {
 120         int i;
 121         unsigned long timeout;
 122
 123         timeout = __timeout(br);
 124
 125         write_lock_bh(&br->hash_lock);
 126         for (i=0;i<BR_HASH_SIZE;i++) {
 127                 struct net_bridge_fdb_entry *f;
 128
 129                 f = br->hash[i];
 130                 while (f != NULL) {
 131                         struct net_bridge_fdb_entry *g;
 132
 133                         g = f->next_hash;
 134                         if (!f->is_static &&
 135                             time_before_eq(f->ageing_timer, timeout)) {
 136                                 __hash_unlink(f);
 137                                 br_fdb_put(f);
 138                         }
 139                         f = g;
 140                 }
 141         }
 142         write_unlock_bh(&br->hash_lock);
 143 }
 144
 145 void br_fdb_delete_by_port(struct net_bridge *br, struct net_bridge_port *p)
 146 {
 147         int i;
 148
 149         write_lock_bh(&br->hash_lock);
 150         for (i=0;i<BR_HASH_SIZE;i++) {
 151                 struct net_bridge_fdb_entry *f;
 152
 153                 f = br->hash[i];
 154                 while (f != NULL) {
 155                         struct net_bridge_fdb_entry *g;
 156
 157                         g = f->next_hash;
 158                         if (f->dst == p) {
 159                                 __hash_unlink(f);
 160                                 br_fdb_put(f);
 161                         }
 162                         f = g;
 163                 }
 164         }
 165         write_unlock_bh(&br->hash_lock);
 166 }
 167
 168 struct net_bridge_fdb_entry *br_fdb_get(struct net_bridge *br, unsigned char *addr)
 169 {
 170         struct net_bridge_fdb_entry *fdb;
 171
 172         read_lock_bh(&br->hash_lock);
 173         fdb = br->hash[br_mac_hash(addr)];
 174         while (fdb != NULL) {
 175                 if (!memcmp(fdb->addr.addr, addr, ETH_ALEN)) {
 176                         if (!has_expired(br, fdb)) {
 177                                 atomic_inc(&fdb->use_count);
 178                                 read_unlock_bh(&br->hash_lock);
 179                                 return fdb;
 180                         }
 181
 182                         read_unlock_bh(&br->hash_lock);
 183                         return NULL;
 184                 }
 185
 186                 fdb = fdb->next_hash;
 187         }
 188
 189         read_unlock_bh(&br->hash_lock);
 190         return NULL;
 191 }
 192
 193 void br_fdb_put(struct net_bridge_fdb_entry *ent)
 194 {
 195         if (atomic_dec_and_test(&ent->use_count))
 196                 kfree(ent);
 197 }
 198
 199 int br_fdb_get_entries(struct net_bridge *br,
 200                        unsigned char *_buf,
 201                        int maxnum,
 202                        int offset)
 203 {
 204         int i;
 205         int num;
 206         struct __fdb_entry *walk;
 207
 208         num = 0;
 209         walk = (struct __fdb_entry *)_buf;
 210
 211         read_lock_bh(&br->hash_lock);
 212         for (i=0;i<BR_HASH_SIZE;i++) {
 213                 struct net_bridge_fdb_entry *f;
 214
 215                 f = br->hash[i];
 216                 while (f != NULL && num < maxnum) {
 217                         struct __fdb_entry ent;
 218                         int err;
 219                         struct net_bridge_fdb_entry *g;
 220                         struct net_bridge_fdb_entry **pp;
 221
 222                         if (has_expired(br, f)) {
 223                                 f = f->next_hash;
 224                                 continue;
 225                         }
 226
 227                         if (offset) {
 228                                 offset--;
 229                                 f = f->next_hash;
 230                                 continue;
 231                         }
 232
 233                         copy_fdb(&ent, f);
 234
 235                         atomic_inc(&f->use_count);
 236                         read_unlock_bh(&br->hash_lock);
 237                         err = copy_to_user(walk, &ent, sizeof(struct __fdb_entry));
 238                         read_lock_bh(&br->hash_lock);
 239
 240                         g = f->next_hash;
 241                         pp = f->pprev_hash;
 242                         br_fdb_put(f);
 243
 244                         if (err)
 245                                 goto out_fault;
 246
 247                         if (g == NULL && pp == NULL)
 248                                 goto out_disappeared;
 249
 250                         num++;
 251                         walk++;
 252
 253                         f = g;
 254                 }
 255         }
 256
 257  out:
 258         read_unlock_bh(&br->hash_lock);
 259         return num;
 260
 261  out_disappeared:
 262         num = -EAGAIN;
 263         goto out;
 264
 265  out_fault:
 266         num = -EFAULT;
 267         goto out;
 268 }
 269
 270 static __inline__ void __fdb_possibly_replace(struct net_bridge_fdb_entry *fdb,
 271                                               struct net_bridge_port *source,
 272                                               int is_local)
 273 {
 274         if (!fdb->is_static || is_local) {
 275                 fdb->dst = source;
 276                 fdb->is_local = is_local;
 277                 fdb->is_static = is_local;
 278                 fdb->ageing_timer = jiffies;
 279         }
 280 }
 281
 282 void br_fdb_insert(struct net_bridge *br,
 283                    struct net_bridge_port *source,
 284                    unsigned char *addr,
 285                    int is_local)
 286 {
 287         struct net_bridge_fdb_entry *fdb;
 288         int hash;
 289
 290         hash = br_mac_hash(addr);
 291
 292         write_lock_bh(&br->hash_lock);
 293         fdb = br->hash[hash];
 294         while (fdb != NULL) {
 295                 if (!memcmp(fdb->addr.addr, addr, ETH_ALEN)) {
 296                         /* attempt to update an entry for a local interface */
 297                         if (fdb->is_local) {
 298                                 if (is_local)
 299                                         printk(KERN_INFO "%s: attempt to add"
 300                                                " interface with same source address.\n",
 301                                                source->dev->name);
 302                                 else if (net_ratelimit())
 303                                         printk(KERN_WARNING "%s: received packet with "
 304                                                " own address as source address\n",
 305                                                source->dev->name);
 306                                 goto out;
 307                         }
 308
 309                         __fdb_possibly_replace(fdb, source, is_local);
 310                         goto out;
 311                 }
 312
 313                 fdb = fdb->next_hash;
 314         }
 315
 316         fdb = kmalloc(sizeof(*fdb), GFP_ATOMIC);
 317         if (fdb == NULL)
 318                 goto out;
 319
 320         memcpy(fdb->addr.addr, addr, ETH_ALEN);
 321         atomic_set(&fdb->use_count, 1);
 322         fdb->dst = source;
 323         fdb->is_local = is_local;
 324         fdb->is_static = is_local;
 325         fdb->ageing_timer = jiffies;
 326
 327         __hash_link(br, fdb, hash);
 328
 329  out:
 330         write_unlock_bh(&br->hash_lock);
 331 }