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 const struct nla_policy patch_policy[ODP_PATCH_ATTR_MAX + 1] = {
  89 #ifdef HAVE_NLA_NUL_STRING
  90         [ODP_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[ODP_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, ODP_PATCH_ATTR_MAX, options, patch_policy);
 106         if (err)
 107                 return err;
 108
 109         if (!a[ODP_PATCH_ATTR_PEER] || VERIFY_NUL_STRING(a[ODP_PATCH_ATTR_PEER], IFNAMSIZ - 1))
 110                 return -EINVAL;
 111
 112         peer_name = nla_data(a[ODP_PATCH_ATTR_PEER]);
 113         if (!strcmp(patch_vport->name, peer_name))
 114                 return -EINVAL;
 115
 116         strcpy(patchconf->peer_name, peer_name);
 117
 118         return 0;
 119 }
 120
 121 static struct vport *patch_create(const struct vport_parms *parms)
 122 {
 123         struct vport *vport;
 124         struct patch_vport *patch_vport;
 125         const char *peer_name;
 126         struct patch_config *patchconf;
 127         int err;
 128
 129         vport = vport_alloc(sizeof(struct patch_vport), &patch_vport_ops, parms);
 130         if (IS_ERR(vport)) {
 131                 err = PTR_ERR(vport);
 132                 goto error;
 133         }
 134
 135         patch_vport = patch_vport_priv(vport);
 136
 137         strcpy(patch_vport->name, parms->name);
 138
 139         patchconf = kmalloc(sizeof(struct patch_config), GFP_KERNEL);
 140         if (!patchconf) {
 141                 err = -ENOMEM;
 142                 goto error_free_vport;
 143         }
 144
 145         err = patch_set_config(vport, parms->options, patchconf);
 146         if (err)
 147                 goto error_free_patchconf;
 148
 149         vport_gen_rand_ether_addr(patchconf->eth_addr);
 150
 151         /* Make the default MTU fairly large so that it doesn't become the
 152          * bottleneck on systems using jumbo frames. */
 153         patchconf->mtu = 65535;
 154
 155         rcu_assign_pointer(patch_vport->patchconf, patchconf);
 156
 157         peer_name = patchconf->peer_name;
 158         hlist_add_head(&patch_vport->hash_node, hash_bucket(peer_name));
 159         rcu_assign_pointer(patch_vport->peer, vport_locate(peer_name));
 160         update_peers(patch_vport->name, vport);
 161
 162         return vport;
 163
 164 error_free_patchconf:
 165         kfree(patchconf);
 166 error_free_vport:
 167         vport_free(vport);
 168 error:
 169         return ERR_PTR(err);
 170 }
 171
 172 static void free_port_rcu(struct rcu_head *rcu)
 173 {
 174         struct patch_vport *patch_vport = container_of(rcu,
 175                                           struct patch_vport, rcu);
 176
 177         kfree((struct patch_config __force *)patch_vport->patchconf);
 178         vport_free(vport_from_priv(patch_vport));
 179 }
 180
 181 static int patch_destroy(struct vport *vport)
 182 {
 183         struct patch_vport *patch_vport = patch_vport_priv(vport);
 184
 185         update_peers(patch_vport->name, NULL);
 186         hlist_del(&patch_vport->hash_node);
 187         call_rcu(&patch_vport->rcu, free_port_rcu);
 188
 189         return 0;
 190 }
 191
 192 static int patch_set_options(struct vport *vport, struct nlattr *options)
 193 {
 194         struct patch_vport *patch_vport = patch_vport_priv(vport);
 195         struct patch_config *patchconf;
 196         int err;
 197
 198         patchconf = kmemdup(rtnl_dereference(patch_vport->patchconf),
 199                           sizeof(struct patch_config), GFP_KERNEL);
 200         if (!patchconf) {
 201                 err = -ENOMEM;
 202                 goto error;
 203         }
 204
 205         err = patch_set_config(vport, options, patchconf);
 206         if (err)
 207                 goto error_free;
 208
 209         assign_config_rcu(vport, patchconf);
 210
 211         hlist_del(&patch_vport->hash_node);
 212
 213         rcu_assign_pointer(patch_vport->peer, vport_locate(patchconf->peer_name));
 214         hlist_add_head(&patch_vport->hash_node, hash_bucket(patchconf->peer_name));
 215
 216         return 0;
 217
 218 error_free:
 219         kfree(patchconf);
 220 error:
 221         return err;
 222 }
 223
 224 static void update_peers(const char *name, struct vport *vport)
 225 {
 226         struct hlist_head *bucket = hash_bucket(name);
 227         struct patch_vport *peer_vport;
 228         struct hlist_node *node;
 229
 230         hlist_for_each_entry(peer_vport, node, bucket, hash_node) {
 231                 const char *peer_name;
 232
 233                 peer_name = rtnl_dereference(peer_vport->patchconf)->peer_name;
 234                 if (!strcmp(peer_name, name))
 235                         rcu_assign_pointer(peer_vport->peer, vport);
 236         }
 237 }
 238
 239 static int patch_set_mtu(struct vport *vport, int mtu)
 240 {
 241         struct patch_vport *patch_vport = patch_vport_priv(vport);
 242         struct patch_config *patchconf;
 243
 244         patchconf = kmemdup(rtnl_dereference(patch_vport->patchconf),
 245                           sizeof(struct patch_config), GFP_KERNEL);
 246         if (!patchconf)
 247                 return -ENOMEM;
 248
 249         patchconf->mtu = mtu;
 250         assign_config_rcu(vport, patchconf);
 251
 252         return 0;
 253 }
 254
 255 static int patch_set_addr(struct vport *vport, const unsigned char *addr)
 256 {
 257         struct patch_vport *patch_vport = patch_vport_priv(vport);
 258         struct patch_config *patchconf;
 259
 260         patchconf = kmemdup(rtnl_dereference(patch_vport->patchconf),
 261                           sizeof(struct patch_config), GFP_KERNEL);
 262         if (!patchconf)
 263                 return -ENOMEM;
 264
 265         memcpy(patchconf->eth_addr, addr, ETH_ALEN);
 266         assign_config_rcu(vport, patchconf);
 267
 268         return 0;
 269 }
 270
 271
 272 static const char *patch_get_name(const struct vport *vport)
 273 {
 274         const struct patch_vport *patch_vport = patch_vport_priv(vport);
 275         return patch_vport->name;
 276 }
 277
 278 static const unsigned char *patch_get_addr(const struct vport *vport)
 279 {
 280         const struct patch_vport *patch_vport = patch_vport_priv(vport);
 281         return rcu_dereference_rtnl(patch_vport->patchconf)->eth_addr;
 282 }
 283
 284 static int patch_get_options(const struct vport *vport, struct sk_buff *skb)
 285 {
 286         struct patch_vport *patch_vport = patch_vport_priv(vport);
 287         struct patch_config *patchconf = rcu_dereference_rtnl(patch_vport->patchconf);
 288
 289         return nla_put_string(skb, ODP_PATCH_ATTR_PEER, patchconf->peer_name);
 290 }
 291
 292 static int patch_get_mtu(const struct vport *vport)
 293 {
 294         const struct patch_vport *patch_vport = patch_vport_priv(vport);
 295         return rcu_dereference_rtnl(patch_vport->patchconf)->mtu;
 296 }
 297
 298 static int patch_send(struct vport *vport, struct sk_buff *skb)
 299 {
 300         struct patch_vport *patch_vport = patch_vport_priv(vport);
 301         struct vport *peer = rcu_dereference(patch_vport->peer);
 302         int skb_len = skb->len;
 303
 304         if (!peer) {
 305                 kfree_skb(skb);
 306                 vport_record_error(vport, VPORT_E_TX_DROPPED);
 307
 308                 return 0;
 309         }
 310
 311         vport_receive(peer, skb);
 312         return skb_len;
 313 }
 314
 315 const struct vport_ops patch_vport_ops = {
 316         .type           = ODP_VPORT_TYPE_PATCH,
 317         .flags          = VPORT_F_GEN_STATS,
 318         .init           = patch_init,
 319         .exit           = patch_exit,
 320         .create         = patch_create,
 321         .destroy        = patch_destroy,
 322         .set_mtu        = patch_set_mtu,
 323         .set_addr       = patch_set_addr,
 324         .get_name       = patch_get_name,
 325         .get_addr       = patch_get_addr,
 326         .get_options    = patch_get_options,
 327         .set_options    = patch_set_options,
 328         .get_dev_flags  = vport_gen_get_dev_flags,
 329         .is_running     = vport_gen_is_running,
 330         .get_operstate  = vport_gen_get_operstate,
 331         .get_mtu        = patch_get_mtu,
 332         .send           = patch_send,
 333 };