datapath/vport-patch.c

   1 /*
   2  * Copyright (c) 2010 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 device_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 device_config __rcu *devconf;
  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 device_config *c = container_of(rcu, struct device_config, rcu);
  53         kfree(c);
  54 }
  55
  56 static void assign_config_rcu(struct vport *vport,
  57                               struct device_config *new_config)
  58 {
  59         struct patch_vport *patch_vport = patch_vport_priv(vport);
  60         struct device_config *old_config;
  61
  62         old_config = rtnl_dereference(patch_vport->devconf);
  63         rcu_assign_pointer(patch_vport->devconf, 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 set_config(struct vport *vport, const void *config,
  89                         struct device_config *devconf)
  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(devconf->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         int err;
 110
 111         vport = vport_alloc(sizeof(struct patch_vport), &patch_vport_ops, parms);
 112         if (IS_ERR(vport)) {
 113                 err = PTR_ERR(vport);
 114                 goto error;
 115         }
 116
 117         patch_vport = patch_vport_priv(vport);
 118
 119         strcpy(patch_vport->name, parms->name);
 120
 121         patch_vport->devconf = kmalloc(sizeof(struct device_config), GFP_KERNEL);
 122         if (!patch_vport->devconf) {
 123                 err = -ENOMEM;
 124                 goto error_free_vport;
 125         }
 126
 127         err = set_config(vport, parms->config, patch_vport->devconf);
 128         if (err)
 129                 goto error_free_devconf;
 130
 131         vport_gen_rand_ether_addr(patch_vport->devconf->eth_addr);
 132
 133         /* Make the default MTU fairly large so that it doesn't become the
 134          * bottleneck on systems using jumbo frames. */
 135         patch_vport->devconf->mtu = 65535;
 136
 137         peer_name = patch_vport->devconf->peer_name;
 138         hlist_add_head(&patch_vport->hash_node, hash_bucket(peer_name));
 139
 140         rcu_assign_pointer(patch_vport->peer, vport_locate(peer_name));
 141         update_peers(patch_vport->name, vport);
 142
 143         return vport;
 144
 145 error_free_devconf:
 146         kfree(patch_vport->devconf);
 147 error_free_vport:
 148         vport_free(vport);
 149 error:
 150         return ERR_PTR(err);
 151 }
 152
 153 static int patch_modify(struct vport *vport, struct odp_port *port)
 154 {
 155         struct patch_vport *patch_vport = patch_vport_priv(vport);
 156         struct device_config *devconf;
 157         int err;
 158
 159         devconf = kmemdup(rtnl_dereference(patch_vport->devconf),
 160                           sizeof(struct device_config), GFP_KERNEL);
 161         if (!devconf) {
 162                 err = -ENOMEM;
 163                 goto error;
 164         }
 165
 166         err = set_config(vport, port->config, devconf);
 167         if (err)
 168                 goto error_free;
 169
 170         assign_config_rcu(vport, devconf);
 171
 172         hlist_del(&patch_vport->hash_node);
 173
 174         rcu_assign_pointer(patch_vport->peer, vport_locate(devconf->peer_name));
 175         hlist_add_head(&patch_vport->hash_node, hash_bucket(devconf->peer_name));
 176
 177         return 0;
 178
 179 error_free:
 180         kfree(devconf);
 181 error:
 182         return err;
 183 }
 184
 185 static void free_port_rcu(struct rcu_head *rcu)
 186 {
 187         struct patch_vport *patch_vport = container_of(rcu,
 188                                                       struct patch_vport, rcu);
 189
 190         kfree(patch_vport->devconf);
 191         vport_free(vport_from_priv(patch_vport));
 192 }
 193
 194 static int patch_destroy(struct vport *vport)
 195 {
 196         struct patch_vport *patch_vport = patch_vport_priv(vport);
 197
 198         update_peers(patch_vport->name, NULL);
 199         hlist_del(&patch_vport->hash_node);
 200         call_rcu(&patch_vport->rcu, free_port_rcu);
 201
 202         return 0;
 203 }
 204
 205 static void update_peers(const char *name, struct vport *vport)
 206 {
 207         struct hlist_head *bucket = hash_bucket(name);
 208         struct patch_vport *peer_vport;
 209         struct hlist_node *node;
 210
 211         hlist_for_each_entry(peer_vport, node, bucket, hash_node) {
 212                 const char *peer_name;
 213
 214                 peer_name = rtnl_dereference(peer_vport->devconf)->peer_name;
 215                 if (!strcmp(peer_name, name))
 216                         rcu_assign_pointer(peer_vport->peer, vport);
 217         }
 218 }
 219
 220 static int patch_set_mtu(struct vport *vport, int mtu)
 221 {
 222         struct patch_vport *patch_vport = patch_vport_priv(vport);
 223         struct device_config *devconf;
 224
 225         devconf = kmemdup(rtnl_dereference(patch_vport->devconf),
 226                           sizeof(struct device_config), GFP_KERNEL);
 227         if (!devconf)
 228                 return -ENOMEM;
 229
 230         devconf->mtu = mtu;
 231         assign_config_rcu(vport, devconf);
 232
 233         return 0;
 234 }
 235
 236 static int patch_set_addr(struct vport *vport, const unsigned char *addr)
 237 {
 238         struct patch_vport *patch_vport = patch_vport_priv(vport);
 239         struct device_config *devconf;
 240
 241         devconf = kmemdup(rtnl_dereference(patch_vport->devconf),
 242                           sizeof(struct device_config), GFP_KERNEL);
 243         if (!devconf)
 244                 return -ENOMEM;
 245
 246         memcpy(devconf->eth_addr, addr, ETH_ALEN);
 247         assign_config_rcu(vport, devconf);
 248
 249         return 0;
 250 }
 251
 252
 253 static const char *patch_get_name(const struct vport *vport)
 254 {
 255         const struct patch_vport *patch_vport = patch_vport_priv(vport);
 256         return patch_vport->name;
 257 }
 258
 259 static const unsigned char *patch_get_addr(const struct vport *vport)
 260 {
 261         const struct patch_vport *patch_vport = patch_vport_priv(vport);
 262         return rcu_dereference_rtnl(patch_vport->devconf)->eth_addr;
 263 }
 264
 265 static void patch_get_config(const struct vport *vport, void *config)
 266 {
 267         const struct patch_vport *patch_vport = patch_vport_priv(vport);
 268         const char *peer_name;
 269
 270         peer_name = rcu_dereference_rtnl(patch_vport->devconf)->peer_name;
 271         strlcpy(config, peer_name, VPORT_CONFIG_SIZE);
 272 }
 273
 274 static int patch_get_mtu(const struct vport *vport)
 275 {
 276         const struct patch_vport *patch_vport = patch_vport_priv(vport);
 277         return rcu_dereference_rtnl(patch_vport->devconf)->mtu;
 278 }
 279
 280 static int patch_send(struct vport *vport, struct sk_buff *skb)
 281 {
 282         struct patch_vport *patch_vport = patch_vport_priv(vport);
 283         struct vport *peer = rcu_dereference(patch_vport->peer);
 284         int skb_len = skb->len;
 285
 286         if (!peer) {
 287                 kfree_skb(skb);
 288                 vport_record_error(vport, VPORT_E_TX_DROPPED);
 289
 290                 return 0;
 291         }
 292
 293         vport_receive(peer, skb);
 294         return skb_len;
 295 }
 296
 297 const struct vport_ops patch_vport_ops = {
 298         .type           = "patch",
 299         .flags          = VPORT_F_GEN_STATS,
 300         .init           = patch_init,
 301         .exit           = patch_exit,
 302         .create         = patch_create,
 303         .modify         = patch_modify,
 304         .destroy        = patch_destroy,
 305         .set_mtu        = patch_set_mtu,
 306         .set_addr       = patch_set_addr,
 307         .get_name       = patch_get_name,
 308         .get_addr       = patch_get_addr,
 309         .get_config     = patch_get_config,
 310         .get_dev_flags  = vport_gen_get_dev_flags,
 311         .is_running     = vport_gen_is_running,
 312         .get_operstate  = vport_gen_get_operstate,
 313         .get_mtu        = patch_get_mtu,
 314         .send           = patch_send,
 315 };