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 "compat.h"
  15 #include "datapath.h"
  16 #include "vport.h"
  17 #include "vport-generic.h"
  18
  19 struct patch_config {
  20         struct rcu_head rcu;
  21
  22         char peer_name[IFNAMSIZ];
  23         unsigned char eth_addr[ETH_ALEN];
  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 const struct nla_policy patch_policy[OVS_PATCH_ATTR_MAX + 1] = {
  89 #ifdef HAVE_NLA_NUL_STRING
  90         [OVS_PATCH_ATTR_PEER] = { .type = NLA_NUL_STRING, .len = IFNAMSIZ - 1 },
  91 #endif
  92 };
  93
  94 static int patch_set_config(struct vport *vport, const struct nlattr *options,
  95                             struct patch_config *patchconf)
  96 {
  97         struct patch_vport *patch_vport = patch_vport_priv(vport);
  98         struct nlattr *a[OVS_PATCH_ATTR_MAX + 1];
  99         const char *peer_name;
 100         int err;
 101
 102         if (!options)
 103                 return -EINVAL;
 104
 105         err = nla_parse_nested(a, OVS_PATCH_ATTR_MAX, options, patch_policy);
 106         if (err)
 107                 return err;
 108
 109         if (!a[OVS_PATCH_ATTR_PEER] ||
 110             CHECK_NUL_STRING(a[OVS_PATCH_ATTR_PEER], IFNAMSIZ - 1))
 111                 return -EINVAL;
 112
 113         peer_name = nla_data(a[OVS_PATCH_ATTR_PEER]);
 114         if (!strcmp(patch_vport->name, peer_name))
 115                 return -EINVAL;
 116
 117         strcpy(patchconf->peer_name, peer_name);
 118
 119         return 0;
 120 }
 121
 122 static struct vport *patch_create(const struct vport_parms *parms)
 123 {
 124         struct vport *vport;
 125         struct patch_vport *patch_vport;
 126         const char *peer_name;
 127         struct patch_config *patchconf;
 128         int err;
 129
 130         vport = vport_alloc(sizeof(struct patch_vport), &patch_vport_ops, parms);
 131         if (IS_ERR(vport)) {
 132                 err = PTR_ERR(vport);
 133                 goto error;
 134         }
 135
 136         patch_vport = patch_vport_priv(vport);
 137
 138         strcpy(patch_vport->name, parms->name);
 139
 140         patchconf = kmalloc(sizeof(struct patch_config), GFP_KERNEL);
 141         if (!patchconf) {
 142                 err = -ENOMEM;
 143                 goto error_free_vport;
 144         }
 145
 146         err = patch_set_config(vport, parms->options, patchconf);
 147         if (err)
 148                 goto error_free_patchconf;
 149
 150         vport_gen_rand_ether_addr(patchconf->eth_addr);
 151
 152         rcu_assign_pointer(patch_vport->patchconf, patchconf);
 153
 154         peer_name = patchconf->peer_name;
 155         hlist_add_head(&patch_vport->hash_node, hash_bucket(peer_name));
 156         rcu_assign_pointer(patch_vport->peer, vport_locate(peer_name));
 157         update_peers(patch_vport->name, vport);
 158
 159         return vport;
 160
 161 error_free_patchconf:
 162         kfree(patchconf);
 163 error_free_vport:
 164         vport_free(vport);
 165 error:
 166         return ERR_PTR(err);
 167 }
 168
 169 static void free_port_rcu(struct rcu_head *rcu)
 170 {
 171         struct patch_vport *patch_vport = container_of(rcu,
 172                                           struct patch_vport, rcu);
 173
 174         kfree((struct patch_config __force *)patch_vport->patchconf);
 175         vport_free(vport_from_priv(patch_vport));
 176 }
 177
 178 static void patch_destroy(struct vport *vport)
 179 {
 180         struct patch_vport *patch_vport = patch_vport_priv(vport);
 181
 182         update_peers(patch_vport->name, NULL);
 183         hlist_del(&patch_vport->hash_node);
 184         call_rcu(&patch_vport->rcu, free_port_rcu);
 185 }
 186
 187 static int patch_set_options(struct vport *vport, struct nlattr *options)
 188 {
 189         struct patch_vport *patch_vport = patch_vport_priv(vport);
 190         struct patch_config *patchconf;
 191         int err;
 192
 193         patchconf = kmemdup(rtnl_dereference(patch_vport->patchconf),
 194                           sizeof(struct patch_config), GFP_KERNEL);
 195         if (!patchconf) {
 196                 err = -ENOMEM;
 197                 goto error;
 198         }
 199
 200         err = patch_set_config(vport, options, patchconf);
 201         if (err)
 202                 goto error_free;
 203
 204         assign_config_rcu(vport, patchconf);
 205
 206         hlist_del(&patch_vport->hash_node);
 207
 208         rcu_assign_pointer(patch_vport->peer, vport_locate(patchconf->peer_name));
 209         hlist_add_head(&patch_vport->hash_node, hash_bucket(patchconf->peer_name));
 210
 211         return 0;
 212
 213 error_free:
 214         kfree(patchconf);
 215 error:
 216         return err;
 217 }
 218
 219 static void update_peers(const char *name, struct vport *vport)
 220 {
 221         struct hlist_head *bucket = hash_bucket(name);
 222         struct patch_vport *peer_vport;
 223         struct hlist_node *node;
 224
 225         hlist_for_each_entry(peer_vport, node, bucket, hash_node) {
 226                 const char *peer_name;
 227
 228                 peer_name = rtnl_dereference(peer_vport->patchconf)->peer_name;
 229                 if (!strcmp(peer_name, name))
 230                         rcu_assign_pointer(peer_vport->peer, vport);
 231         }
 232 }
 233
 234 static int patch_set_addr(struct vport *vport, const unsigned char *addr)
 235 {
 236         struct patch_vport *patch_vport = patch_vport_priv(vport);
 237         struct patch_config *patchconf;
 238
 239         patchconf = kmemdup(rtnl_dereference(patch_vport->patchconf),
 240                           sizeof(struct patch_config), GFP_KERNEL);
 241         if (!patchconf)
 242                 return -ENOMEM;
 243
 244         memcpy(patchconf->eth_addr, addr, ETH_ALEN);
 245         assign_config_rcu(vport, patchconf);
 246
 247         return 0;
 248 }
 249
 250
 251 static const char *patch_get_name(const struct vport *vport)
 252 {
 253         const struct patch_vport *patch_vport = patch_vport_priv(vport);
 254         return patch_vport->name;
 255 }
 256
 257 static const unsigned char *patch_get_addr(const struct vport *vport)
 258 {
 259         const struct patch_vport *patch_vport = patch_vport_priv(vport);
 260         return rcu_dereference_rtnl(patch_vport->patchconf)->eth_addr;
 261 }
 262
 263 static int patch_get_options(const struct vport *vport, struct sk_buff *skb)
 264 {
 265         struct patch_vport *patch_vport = patch_vport_priv(vport);
 266         struct patch_config *patchconf = rcu_dereference_rtnl(patch_vport->patchconf);
 267
 268         return nla_put_string(skb, OVS_PATCH_ATTR_PEER, patchconf->peer_name);
 269 }
 270
 271 static int patch_send(struct vport *vport, struct sk_buff *skb)
 272 {
 273         struct patch_vport *patch_vport = patch_vport_priv(vport);
 274         struct vport *peer = rcu_dereference(patch_vport->peer);
 275         int skb_len = skb->len;
 276
 277         if (!peer) {
 278                 kfree_skb(skb);
 279                 vport_record_error(vport, VPORT_E_TX_DROPPED);
 280
 281                 return 0;
 282         }
 283
 284         vport_receive(peer, skb);
 285         return skb_len;
 286 }
 287
 288 const struct vport_ops patch_vport_ops = {
 289         .type           = OVS_VPORT_TYPE_PATCH,
 290         .init           = patch_init,
 291         .exit           = patch_exit,
 292         .create         = patch_create,
 293         .destroy        = patch_destroy,
 294         .set_addr       = patch_set_addr,
 295         .get_name       = patch_get_name,
 296         .get_addr       = patch_get_addr,
 297         .get_options    = patch_get_options,
 298         .set_options    = patch_set_options,
 299         .get_dev_flags  = vport_gen_get_dev_flags,
 300         .is_running     = vport_gen_is_running,
 301         .get_operstate  = vport_gen_get_operstate,
 302         .send           = patch_send,
 303 };