datapath/vport-patch.c

   1 /*
   2  * Copyright (c) 2007-2012 Nicira, Inc.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of version 2 of the GNU General Public
   6  * License as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful, but
   9  * WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this program; if not, write to the Free Software
  15  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  16  * 02110-1301, USA
  17  */
  18
  19 #include <linux/kernel.h>
  20 #include <linux/jhash.h>
  21 #include <linux/list.h>
  22 #include <linux/rtnetlink.h>
  23 #include <net/net_namespace.h>
  24
  25 #include "compat.h"
  26 #include "datapath.h"
  27 #include "vport.h"
  28
  29 struct patch_config {
  30         struct rcu_head rcu;
  31
  32         char peer_name[IFNAMSIZ];
  33 };
  34
  35 struct patch_vport {
  36         struct rcu_head rcu;
  37
  38         char name[IFNAMSIZ];
  39
  40         /* Protected by RTNL lock. */
  41         struct hlist_node hash_node;
  42
  43         struct vport __rcu *peer;
  44         struct patch_config __rcu *patchconf;
  45 };
  46
  47 /* Protected by RTNL lock. */
  48 static struct hlist_head *peer_table;
  49 #define PEER_HASH_BUCKETS 256
  50
  51 static void update_peers(struct net *, const char *name, struct vport *);
  52
  53 static struct patch_vport *patch_vport_priv(const struct vport *vport)
  54 {
  55         return vport_priv(vport);
  56 }
  57
  58 /* RCU callback. */
  59 static void free_config(struct rcu_head *rcu)
  60 {
  61         struct patch_config *c = container_of(rcu, struct patch_config, rcu);
  62         kfree(c);
  63 }
  64
  65 static void assign_config_rcu(struct vport *vport,
  66                               struct patch_config *new_config)
  67 {
  68         struct patch_vport *patch_vport = patch_vport_priv(vport);
  69         struct patch_config *old_config;
  70
  71         old_config = rtnl_dereference(patch_vport->patchconf);
  72         rcu_assign_pointer(patch_vport->patchconf, new_config);
  73         call_rcu(&old_config->rcu, free_config);
  74 }
  75
  76 static struct hlist_head *hash_bucket(struct net *net, const char *name)
  77 {
  78         unsigned int hash = jhash(name, strlen(name), (unsigned long) net);
  79         return &peer_table[hash & (PEER_HASH_BUCKETS - 1)];
  80 }
  81
  82 static int patch_init(void)
  83 {
  84         peer_table = kzalloc(PEER_HASH_BUCKETS * sizeof(struct hlist_head),
  85                             GFP_KERNEL);
  86         if (!peer_table)
  87                 return -ENOMEM;
  88
  89         return 0;
  90 }
  91
  92 static void patch_exit(void)
  93 {
  94         kfree(peer_table);
  95 }
  96
  97 static const struct nla_policy patch_policy[OVS_PATCH_ATTR_MAX + 1] = {
  98 #ifdef HAVE_NLA_NUL_STRING
  99         [OVS_PATCH_ATTR_PEER] = { .type = NLA_NUL_STRING, .len = IFNAMSIZ - 1 },
 100 #endif
 101 };
 102
 103 static int patch_set_config(struct vport *vport, const struct nlattr *options,
 104                             struct patch_config *patchconf)
 105 {
 106         struct patch_vport *patch_vport = patch_vport_priv(vport);
 107         struct nlattr *a[OVS_PATCH_ATTR_MAX + 1];
 108         const char *peer_name;
 109         int err;
 110
 111         if (!options)
 112                 return -EINVAL;
 113
 114         err = nla_parse_nested(a, OVS_PATCH_ATTR_MAX, options, patch_policy);
 115         if (err)
 116                 return err;
 117
 118         if (!a[OVS_PATCH_ATTR_PEER] ||
 119             CHECK_NUL_STRING(a[OVS_PATCH_ATTR_PEER], IFNAMSIZ - 1))
 120                 return -EINVAL;
 121
 122         peer_name = nla_data(a[OVS_PATCH_ATTR_PEER]);
 123         if (!strcmp(patch_vport->name, peer_name))
 124                 return -EINVAL;
 125
 126         strcpy(patchconf->peer_name, peer_name);
 127
 128         return 0;
 129 }
 130
 131 static struct vport *patch_create(const struct vport_parms *parms)
 132 {
 133         struct vport *vport;
 134         struct patch_vport *patch_vport;
 135         const char *peer_name;
 136         struct patch_config *patchconf;
 137         struct net *net = ovs_dp_get_net(parms->dp);
 138         int err;
 139
 140         vport = ovs_vport_alloc(sizeof(struct patch_vport),
 141                                 &ovs_patch_vport_ops, parms);
 142         if (IS_ERR(vport)) {
 143                 err = PTR_ERR(vport);
 144                 goto error;
 145         }
 146
 147         patch_vport = patch_vport_priv(vport);
 148
 149         strcpy(patch_vport->name, parms->name);
 150
 151         patchconf = kmalloc(sizeof(struct patch_config), GFP_KERNEL);
 152         if (!patchconf) {
 153                 err = -ENOMEM;
 154                 goto error_free_vport;
 155         }
 156
 157         err = patch_set_config(vport, parms->options, patchconf);
 158         if (err)
 159                 goto error_free_patchconf;
 160
 161         rcu_assign_pointer(patch_vport->patchconf, patchconf);
 162
 163         peer_name = patchconf->peer_name;
 164         hlist_add_head(&patch_vport->hash_node, hash_bucket(net, peer_name));
 165         rcu_assign_pointer(patch_vport->peer, ovs_vport_locate(net, peer_name));
 166         update_peers(net, patch_vport->name, vport);
 167
 168         return vport;
 169
 170 error_free_patchconf:
 171         kfree(patchconf);
 172 error_free_vport:
 173         ovs_vport_free(vport);
 174 error:
 175         return ERR_PTR(err);
 176 }
 177
 178 static void free_port_rcu(struct rcu_head *rcu)
 179 {
 180         struct patch_vport *patch_vport = container_of(rcu,
 181                                           struct patch_vport, rcu);
 182
 183         kfree((struct patch_config __force *)patch_vport->patchconf);
 184         ovs_vport_free(vport_from_priv(patch_vport));
 185 }
 186
 187 static void patch_destroy(struct vport *vport)
 188 {
 189         struct patch_vport *patch_vport = patch_vport_priv(vport);
 190
 191         update_peers(ovs_dp_get_net(vport->dp), patch_vport->name, NULL);
 192         hlist_del(&patch_vport->hash_node);
 193         call_rcu(&patch_vport->rcu, free_port_rcu);
 194 }
 195
 196 static int patch_set_options(struct vport *vport, struct nlattr *options)
 197 {
 198         struct patch_vport *patch_vport = patch_vport_priv(vport);
 199         struct patch_config *patchconf;
 200         int err;
 201
 202         patchconf = kmemdup(rtnl_dereference(patch_vport->patchconf),
 203                           sizeof(struct patch_config), GFP_KERNEL);
 204         if (!patchconf) {
 205                 err = -ENOMEM;
 206                 goto error;
 207         }
 208
 209         err = patch_set_config(vport, options, patchconf);
 210         if (err)
 211                 goto error_free;
 212
 213         assign_config_rcu(vport, patchconf);
 214
 215         hlist_del(&patch_vport->hash_node);
 216
 217         rcu_assign_pointer(patch_vport->peer,
 218                 ovs_vport_locate(ovs_dp_get_net(vport->dp), patchconf->peer_name));
 219
 220         hlist_add_head(&patch_vport->hash_node,
 221                        hash_bucket(ovs_dp_get_net(vport->dp), patchconf->peer_name));
 222
 223         return 0;
 224 error_free:
 225         kfree(patchconf);
 226 error:
 227         return err;
 228 }
 229
 230 static void update_peers(struct net *net, const char *name, struct vport *vport)
 231 {
 232         struct hlist_head *bucket = hash_bucket(net, name);
 233         struct patch_vport *peer_vport;
 234         struct hlist_node *node;
 235
 236         hlist_for_each_entry(peer_vport, node, bucket, hash_node) {
 237                 struct vport *curr_vport = vport_from_priv(peer_vport);
 238                 const char *peer_name;
 239
 240                 peer_name = rtnl_dereference(peer_vport->patchconf)->peer_name;
 241                 if (!strcmp(peer_name, name) && net_eq(ovs_dp_get_net(curr_vport->dp), net))
 242                         rcu_assign_pointer(peer_vport->peer, vport);
 243         }
 244 }
 245
 246 static const char *patch_get_name(const struct vport *vport)
 247 {
 248         const struct patch_vport *patch_vport = patch_vport_priv(vport);
 249         return patch_vport->name;
 250 }
 251
 252 static int patch_get_options(const struct vport *vport, struct sk_buff *skb)
 253 {
 254         struct patch_vport *patch_vport = patch_vport_priv(vport);
 255         struct patch_config *patchconf = rcu_dereference_rtnl(patch_vport->patchconf);
 256
 257         return nla_put_string(skb, OVS_PATCH_ATTR_PEER, patchconf->peer_name);
 258 }
 259
 260 static int patch_send(struct vport *vport, struct sk_buff *skb)
 261 {
 262         struct patch_vport *patch_vport = patch_vport_priv(vport);
 263         struct vport *peer = rcu_dereference(patch_vport->peer);
 264         int skb_len = skb->len;
 265
 266         if (!peer) {
 267                 kfree_skb(skb);
 268                 ovs_vport_record_error(vport, VPORT_E_TX_DROPPED);
 269
 270                 return 0;
 271         }
 272
 273         ovs_vport_receive(peer, skb);
 274         return skb_len;
 275 }
 276
 277 const struct vport_ops ovs_patch_vport_ops = {
 278         .type           = OVS_VPORT_TYPE_PATCH,
 279         .init           = patch_init,
 280         .exit           = patch_exit,
 281         .create         = patch_create,
 282         .destroy        = patch_destroy,
 283         .get_name       = patch_get_name,
 284         .get_options    = patch_get_options,
 285         .set_options    = patch_set_options,
 286         .send           = patch_send,
 287 };