datapath/vport-patch.c

   1 /*
   2  * Copyright (c) 2010, 2011 Nicira Networks.
   3  * Distributed under the terms of the GNU GPL version 2.
   4  *
   5  * Significant portions of this file may be copied from parts of the Linux
   6  * kernel, by Linus Torvalds and others.
   7  */
   8
   9 #include <linux/dcache.h>
  10 #include <linux/kernel.h>
  11 #include <linux/list.h>
  12 #include <linux/rtnetlink.h>
  13
  14 #include "datapath.h"
  15 #include "vport.h"
  16 #include "vport-generic.h"
  17
  18 struct patch_config {
  19         struct rcu_head rcu;
  20
  21         char peer_name[IFNAMSIZ];
  22         unsigned char eth_addr[ETH_ALEN];
  23         unsigned int mtu;
  24 };
  25
  26 struct patch_vport {
  27         struct rcu_head rcu;
  28
  29         char name[IFNAMSIZ];
  30
  31         /* Protected by RTNL lock. */
  32         struct hlist_node hash_node;
  33
  34         struct vport __rcu *peer;
  35         struct patch_config __rcu *patchconf;
  36 };
  37
  38 /* Protected by RTNL lock. */
  39 static struct hlist_head *peer_table;
  40 #define PEER_HASH_BUCKETS 256
  41
  42 static void update_peers(const char *name, struct vport *);
  43
  44 static inline struct patch_vport *patch_vport_priv(const struct vport *vport)
  45 {
  46         return vport_priv(vport);
  47 }
  48
  49 /* RCU callback. */
  50 static void free_config(struct rcu_head *rcu)
  51 {
  52         struct patch_config *c = container_of(rcu, struct patch_config, rcu);
  53         kfree(c);
  54 }
  55
  56 static void assign_config_rcu(struct vport *vport,
  57                               struct patch_config *new_config)
  58 {
  59         struct patch_vport *patch_vport = patch_vport_priv(vport);
  60         struct patch_config *old_config;
  61
  62         old_config = rtnl_dereference(patch_vport->patchconf);
  63         rcu_assign_pointer(patch_vport->patchconf, new_config);
  64         call_rcu(&old_config->rcu, free_config);
  65 }
  66
  67 static struct hlist_head *hash_bucket(const char *name)
  68 {
  69         unsigned int hash = full_name_hash(name, strlen(name));
  70         return &peer_table[hash & (PEER_HASH_BUCKETS - 1)];
  71 }
  72
  73 static int patch_init(void)
  74 {
  75         peer_table = kzalloc(PEER_HASH_BUCKETS * sizeof(struct hlist_head),
  76                             GFP_KERNEL);
  77         if (!peer_table)
  78                 return -ENOMEM;
  79
  80         return 0;
  81 }
  82
  83 static void patch_exit(void)
  84 {
  85         kfree(peer_table);
  86 }
  87
  88 static int patch_set_config(struct vport *vport, const void *config,
  89                             struct patch_config *patchconf)
  90 {
  91         struct patch_vport *patch_vport = patch_vport_priv(vport);
  92         char peer_name[IFNAMSIZ];
  93
  94         strlcpy(peer_name, config, IFNAMSIZ);
  95
  96         if (!strcmp(patch_vport->name, peer_name))
  97                 return -EINVAL;
  98
  99         strcpy(patchconf->peer_name, peer_name);
 100
 101         return 0;
 102 }
 103
 104 static struct vport *patch_create(const struct vport_parms *parms)
 105 {
 106         struct vport *vport;
 107         struct patch_vport *patch_vport;
 108         const char *peer_name;
 109         struct patch_config *patchconf;
 110         int err;
 111
 112         vport = vport_alloc(sizeof(struct patch_vport), &patch_vport_ops, parms);
 113         if (IS_ERR(vport)) {
 114                 err = PTR_ERR(vport);
 115                 goto error;
 116         }
 117
 118         patch_vport = patch_vport_priv(vport);
 119
 120         strcpy(patch_vport->name, parms->name);
 121
 122         patchconf = kmalloc(sizeof(struct patch_config), GFP_KERNEL);
 123         if (!patchconf) {
 124                 err = -ENOMEM;
 125                 goto error_free_vport;
 126         }
 127
 128         err = patch_set_config(vport, parms->config, patchconf);
 129         if (err)
 130                 goto error_free_patchconf;
 131
 132         vport_gen_rand_ether_addr(patchconf->eth_addr);
 133
 134         /* Make the default MTU fairly large so that it doesn't become the
 135          * bottleneck on systems using jumbo frames. */
 136         patchconf->mtu = 65535;
 137
 138         rcu_assign_pointer(patch_vport->patchconf, patchconf);
 139
 140         peer_name = patchconf->peer_name;
 141         hlist_add_head(&patch_vport->hash_node, hash_bucket(peer_name));
 142         rcu_assign_pointer(patch_vport->peer, vport_locate(peer_name));
 143         update_peers(patch_vport->name, vport);
 144
 145         return vport;
 146
 147 error_free_patchconf:
 148         kfree(patchconf);
 149 error_free_vport:
 150         vport_free(vport);
 151 error:
 152         return ERR_PTR(err);
 153 }
 154
 155 static int patch_modify(struct vport *vport, struct odp_port *port)
 156 {
 157         struct patch_vport *patch_vport = patch_vport_priv(vport);
 158         struct patch_config *patchconf;
 159         int err;
 160
 161         patchconf = kmemdup(rtnl_dereference(patch_vport->patchconf),
 162                           sizeof(struct patch_config), GFP_KERNEL);
 163         if (!patchconf) {
 164                 err = -ENOMEM;
 165                 goto error;
 166         }
 167
 168         err = patch_set_config(vport, port->config, patchconf);
 169         if (err)
 170                 goto error_free;
 171
 172         assign_config_rcu(vport, patchconf);
 173
 174         hlist_del(&patch_vport->hash_node);
 175
 176         rcu_assign_pointer(patch_vport->peer, vport_locate(patchconf->peer_name));
 177         hlist_add_head(&patch_vport->hash_node, hash_bucket(patchconf->peer_name));
 178
 179         return 0;
 180
 181 error_free:
 182         kfree(patchconf);
 183 error:
 184         return err;
 185 }
 186
 187 static void free_port_rcu(struct rcu_head *rcu)
 188 {
 189         struct patch_vport *patch_vport = container_of(rcu,
 190                                           struct patch_vport, rcu);
 191
 192         kfree((struct patch_config __force *)patch_vport->patchconf);
 193         vport_free(vport_from_priv(patch_vport));
 194 }
 195
 196 static int patch_destroy(struct vport *vport)
 197 {
 198         struct patch_vport *patch_vport = patch_vport_priv(vport);
 199
 200         update_peers(patch_vport->name, NULL);
 201         hlist_del(&patch_vport->hash_node);
 202         call_rcu(&patch_vport->rcu, free_port_rcu);
 203
 204         return 0;
 205 }
 206
 207 static void update_peers(const char *name, struct vport *vport)
 208 {
 209         struct hlist_head *bucket = hash_bucket(name);
 210         struct patch_vport *peer_vport;
 211         struct hlist_node *node;
 212
 213         hlist_for_each_entry(peer_vport, node, bucket, hash_node) {
 214                 const char *peer_name;
 215
 216                 peer_name = rtnl_dereference(peer_vport->patchconf)->peer_name;
 217                 if (!strcmp(peer_name, name))
 218                         rcu_assign_pointer(peer_vport->peer, vport);
 219         }
 220 }
 221
 222 static int patch_set_mtu(struct vport *vport, int mtu)
 223 {
 224         struct patch_vport *patch_vport = patch_vport_priv(vport);
 225         struct patch_config *patchconf;
 226
 227         patchconf = kmemdup(rtnl_dereference(patch_vport->patchconf),
 228                           sizeof(struct patch_config), GFP_KERNEL);
 229         if (!patchconf)
 230                 return -ENOMEM;
 231
 232         patchconf->mtu = mtu;
 233         assign_config_rcu(vport, patchconf);
 234
 235         return 0;
 236 }
 237
 238 static int patch_set_addr(struct vport *vport, const unsigned char *addr)
 239 {
 240         struct patch_vport *patch_vport = patch_vport_priv(vport);
 241         struct patch_config *patchconf;
 242
 243         patchconf = kmemdup(rtnl_dereference(patch_vport->patchconf),
 244                           sizeof(struct patch_config), GFP_KERNEL);
 245         if (!patchconf)
 246                 return -ENOMEM;
 247
 248         memcpy(patchconf->eth_addr, addr, ETH_ALEN);
 249         assign_config_rcu(vport, patchconf);
 250
 251         return 0;
 252 }
 253
 254
 255 static const char *patch_get_name(const struct vport *vport)
 256 {
 257         const struct patch_vport *patch_vport = patch_vport_priv(vport);
 258         return patch_vport->name;
 259 }
 260
 261 static const unsigned char *patch_get_addr(const struct vport *vport)
 262 {
 263         const struct patch_vport *patch_vport = patch_vport_priv(vport);
 264         return rcu_dereference_rtnl(patch_vport->patchconf)->eth_addr;
 265 }
 266
 267 static void patch_get_config(const struct vport *vport, void *config)
 268 {
 269         const struct patch_vport *patch_vport = patch_vport_priv(vport);
 270         const char *peer_name;
 271
 272         peer_name = rcu_dereference_rtnl(patch_vport->patchconf)->peer_name;
 273         strlcpy(config, peer_name, VPORT_CONFIG_SIZE);
 274 }
 275
 276 static int patch_get_mtu(const struct vport *vport)
 277 {
 278         const struct patch_vport *patch_vport = patch_vport_priv(vport);
 279         return rcu_dereference_rtnl(patch_vport->patchconf)->mtu;
 280 }
 281
 282 static int patch_send(struct vport *vport, struct sk_buff *skb)
 283 {
 284         struct patch_vport *patch_vport = patch_vport_priv(vport);
 285         struct vport *peer = rcu_dereference(patch_vport->peer);
 286         int skb_len = skb->len;
 287
 288         if (!peer) {
 289                 kfree_skb(skb);
 290                 vport_record_error(vport, VPORT_E_TX_DROPPED);
 291
 292                 return 0;
 293         }
 294
 295         vport_receive(peer, skb);
 296         return skb_len;
 297 }
 298
 299 const struct vport_ops patch_vport_ops = {
 300         .type           = ODP_VPORT_TYPE_PATCH,
 301         .flags          = VPORT_F_GEN_STATS,
 302         .init           = patch_init,
 303         .exit           = patch_exit,
 304         .create         = patch_create,
 305         .modify         = patch_modify,
 306         .destroy        = patch_destroy,
 307         .set_mtu        = patch_set_mtu,
 308         .set_addr       = patch_set_addr,
 309         .get_name       = patch_get_name,
 310         .get_addr       = patch_get_addr,
 311         .get_config     = patch_get_config,
 312         .get_dev_flags  = vport_gen_get_dev_flags,
 313         .is_running     = vport_gen_is_running,
 314         .get_operstate  = vport_gen_get_operstate,
 315         .get_mtu        = patch_get_mtu,
 316         .send           = patch_send,
 317 };