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 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),
 131                             &patch_vport_ops, parms);
 132         if (IS_ERR(vport)) {
 133                 err = PTR_ERR(vport);
 134                 goto error;
 135         }
 136
 137         patch_vport = patch_vport_priv(vport);
 138
 139         strcpy(patch_vport->name, parms->name);
 140
 141         patchconf = kmalloc(sizeof(struct patch_config), GFP_KERNEL);
 142         if (!patchconf) {
 143                 err = -ENOMEM;
 144                 goto error_free_vport;
 145         }
 146
 147         err = patch_set_config(vport, parms->options, patchconf);
 148         if (err)
 149                 goto error_free_patchconf;
 150
 151         random_ether_addr(patchconf->eth_addr);
 152
 153         rcu_assign_pointer(patch_vport->patchconf, patchconf);
 154
 155         peer_name = patchconf->peer_name;
 156         hlist_add_head(&patch_vport->hash_node, hash_bucket(peer_name));
 157         rcu_assign_pointer(patch_vport->peer, vport_locate(peer_name));
 158         update_peers(patch_vport->name, vport);
 159
 160         return vport;
 161
 162 error_free_patchconf:
 163         kfree(patchconf);
 164 error_free_vport:
 165         vport_free(vport);
 166 error:
 167         return ERR_PTR(err);
 168 }
 169
 170 static void free_port_rcu(struct rcu_head *rcu)
 171 {
 172         struct patch_vport *patch_vport = container_of(rcu,
 173                                           struct patch_vport, rcu);
 174
 175         kfree((struct patch_config __force *)patch_vport->patchconf);
 176         vport_free(vport_from_priv(patch_vport));
 177 }
 178
 179 static void patch_destroy(struct vport *vport)
 180 {
 181         struct patch_vport *patch_vport = patch_vport_priv(vport);
 182
 183         update_peers(patch_vport->name, NULL);
 184         hlist_del(&patch_vport->hash_node);
 185         call_rcu(&patch_vport->rcu, free_port_rcu);
 186 }
 187
 188 static int patch_set_options(struct vport *vport, struct nlattr *options)
 189 {
 190         struct patch_vport *patch_vport = patch_vport_priv(vport);
 191         struct patch_config *patchconf;
 192         int err;
 193
 194         patchconf = kmemdup(rtnl_dereference(patch_vport->patchconf),
 195                           sizeof(struct patch_config), GFP_KERNEL);
 196         if (!patchconf) {
 197                 err = -ENOMEM;
 198                 goto error;
 199         }
 200
 201         err = patch_set_config(vport, options, patchconf);
 202         if (err)
 203                 goto error_free;
 204
 205         assign_config_rcu(vport, patchconf);
 206
 207         hlist_del(&patch_vport->hash_node);
 208
 209         rcu_assign_pointer(patch_vport->peer, vport_locate(patchconf->peer_name));
 210         hlist_add_head(&patch_vport->hash_node, hash_bucket(patchconf->peer_name));
 211
 212         return 0;
 213
 214 error_free:
 215         kfree(patchconf);
 216 error:
 217         return err;
 218 }
 219
 220 static void update_peers(const char *name, struct vport *vport)
 221 {
 222         struct hlist_head *bucket = hash_bucket(name);
 223         struct patch_vport *peer_vport;
 224         struct hlist_node *node;
 225
 226         hlist_for_each_entry(peer_vport, node, bucket, hash_node) {
 227                 const char *peer_name;
 228
 229                 peer_name = rtnl_dereference(peer_vport->patchconf)->peer_name;
 230                 if (!strcmp(peer_name, name))
 231                         rcu_assign_pointer(peer_vport->peer, vport);
 232         }
 233 }
 234
 235 static int patch_set_addr(struct vport *vport, const unsigned char *addr)
 236 {
 237         struct patch_vport *patch_vport = patch_vport_priv(vport);
 238         struct patch_config *patchconf;
 239
 240         patchconf = kmemdup(rtnl_dereference(patch_vport->patchconf),
 241                           sizeof(struct patch_config), GFP_KERNEL);
 242         if (!patchconf)
 243                 return -ENOMEM;
 244
 245         memcpy(patchconf->eth_addr, addr, ETH_ALEN);
 246         assign_config_rcu(vport, patchconf);
 247
 248         return 0;
 249 }
 250
 251
 252 static const char *patch_get_name(const struct vport *vport)
 253 {
 254         const struct patch_vport *patch_vport = patch_vport_priv(vport);
 255         return patch_vport->name;
 256 }
 257
 258 static const unsigned char *patch_get_addr(const struct vport *vport)
 259 {
 260         const struct patch_vport *patch_vport = patch_vport_priv(vport);
 261         return rcu_dereference_rtnl(patch_vport->patchconf)->eth_addr;
 262 }
 263
 264 static int patch_get_options(const struct vport *vport, struct sk_buff *skb)
 265 {
 266         struct patch_vport *patch_vport = patch_vport_priv(vport);
 267         struct patch_config *patchconf = rcu_dereference_rtnl(patch_vport->patchconf);
 268
 269         return nla_put_string(skb, OVS_PATCH_ATTR_PEER, patchconf->peer_name);
 270 }
 271
 272 static int patch_send(struct vport *vport, struct sk_buff *skb)
 273 {
 274         struct patch_vport *patch_vport = patch_vport_priv(vport);
 275         struct vport *peer = rcu_dereference(patch_vport->peer);
 276         int skb_len = skb->len;
 277
 278         if (!peer) {
 279                 kfree_skb(skb);
 280                 vport_record_error(vport, VPORT_E_TX_DROPPED);
 281
 282                 return 0;
 283         }
 284
 285         vport_receive(peer, skb);
 286         return skb_len;
 287 }
 288
 289 const struct vport_ops patch_vport_ops = {
 290         .type           = OVS_VPORT_TYPE_PATCH,
 291         .init           = patch_init,
 292         .exit           = patch_exit,
 293         .create         = patch_create,
 294         .destroy        = patch_destroy,
 295         .set_addr       = patch_set_addr,
 296         .get_name       = patch_get_name,
 297         .get_addr       = patch_get_addr,
 298         .get_options    = patch_get_options,
 299         .set_options    = patch_set_options,
 300         .get_dev_flags  = vport_gen_get_dev_flags,
 301         .is_running     = vport_gen_is_running,
 302         .get_operstate  = vport_gen_get_operstate,
 303         .send           = patch_send,
 304 };