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
  13 #include "datapath.h"
  14 #include "vport.h"
  15 #include "vport-generic.h"
  16
  17 struct device_config {
  18         struct rcu_head rcu;
  19
  20         unsigned char eth_addr[ETH_ALEN];
  21         unsigned int mtu;
  22 };
  23
  24 struct patch_vport {
  25         char name[IFNAMSIZ];
  26
  27         /* Protected by RTNL lock. */
  28         char peer_name[IFNAMSIZ];
  29         struct hlist_node hash_node;
  30
  31         /* Protected by RCU. */
  32         struct vport *peer;
  33
  34         /* Protected by RCU. */
  35         struct device_config *devconf;
  36 };
  37
  38 /* Protected by RTNL lock. */
  39 static struct hlist_head *peer_table;
  40 #define PEER_HASH_BUCKETS 256
  41
  42 static inline struct patch_vport *
  43 patch_vport_priv(const struct vport *vport)
  44 {
  45         return vport_priv(vport);
  46 }
  47
  48 /* RCU callback. */
  49 static void
  50 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
  57 assign_config_rcu(struct vport *vport, 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 = rcu_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 *
  68 hash_bucket(const char *name)
  69 {
  70         unsigned int hash = full_name_hash(name, strlen(name));
  71         return &peer_table[hash & (PEER_HASH_BUCKETS - 1)];
  72 }
  73
  74 static int
  75 patch_init(void)
  76 {
  77         peer_table = kzalloc(PEER_HASH_BUCKETS * sizeof(struct hlist_head),
  78                             GFP_KERNEL);
  79         if (!peer_table)
  80                 return -ENOMEM;
  81
  82         return 0;
  83 }
  84
  85 static void
  86 patch_exit(void)
  87 {
  88         kfree(peer_table);
  89 }
  90
  91 static int
  92 set_config(struct vport *vport, const void __user *uconfig)
  93 {
  94         struct patch_vport *patch_vport = patch_vport_priv(vport);
  95         char peer_name[IFNAMSIZ];
  96         int retval;
  97
  98         retval = strncpy_from_user(peer_name, uconfig, IFNAMSIZ);
  99         if (retval < 0)
 100                 return -EFAULT;
 101         else if (retval >= IFNAMSIZ)
 102                 return -ENAMETOOLONG;
 103
 104         if (!strcmp(patch_vport->name, peer_name))
 105                 return -EINVAL;
 106
 107         strcpy(patch_vport->peer_name, peer_name);
 108
 109         if (vport_get_dp_port(vport)) {
 110                 hlist_del(&patch_vport->hash_node);
 111                 rcu_assign_pointer(patch_vport->peer, vport_locate(patch_vport->peer_name));
 112                 hlist_add_head(&patch_vport->hash_node, hash_bucket(patch_vport->peer_name));
 113         }
 114
 115         return 0;
 116 }
 117
 118 static struct vport *
 119 patch_create(const char *name, const void __user *config)
 120 {
 121         struct vport *vport;
 122         struct patch_vport *patch_vport;
 123         int err;
 124
 125         vport = vport_alloc(sizeof(struct patch_vport), &patch_vport_ops);
 126         if (IS_ERR(vport)) {
 127                 err = PTR_ERR(vport);
 128                 goto error;
 129         }
 130
 131         patch_vport = patch_vport_priv(vport);
 132
 133         strcpy(patch_vport->name, name);
 134
 135         err = set_config(vport, config);
 136         if (err)
 137                 goto error_free_vport;
 138
 139         patch_vport->devconf = kmalloc(sizeof(struct device_config), GFP_KERNEL);
 140         if (!patch_vport->devconf) {
 141                 err = -ENOMEM;
 142                 goto error_free_vport;
 143         }
 144
 145         vport_gen_rand_ether_addr(patch_vport->devconf->eth_addr);
 146         patch_vport->devconf->mtu = ETH_DATA_LEN;
 147
 148         return vport;
 149
 150 error_free_vport:
 151         vport_free(vport);
 152 error:
 153         return ERR_PTR(err);
 154 }
 155
 156 static int
 157 patch_modify(struct vport *vport, const void __user *config)
 158 {
 159         return set_config(vport, config);
 160 }
 161
 162 static int
 163 patch_destroy(struct vport *vport)
 164 {
 165         struct patch_vport *patch_vport = patch_vport_priv(vport);
 166
 167         kfree(patch_vport->devconf);
 168         vport_free(vport);
 169
 170         return 0;
 171 }
 172
 173 static void
 174 update_peers(const char *name, struct vport *vport)
 175 {
 176         struct hlist_head *bucket = hash_bucket(name);
 177         struct patch_vport *peer_vport;
 178         struct hlist_node *node;
 179
 180         hlist_for_each_entry(peer_vport, node, bucket, hash_node)
 181                 if (!strcmp(peer_vport->peer_name, name))
 182                         rcu_assign_pointer(peer_vport->peer, vport);
 183 }
 184
 185 static int
 186 patch_attach(struct vport *vport)
 187 {
 188         struct patch_vport *patch_vport = patch_vport_priv(vport);
 189
 190         hlist_add_head(&patch_vport->hash_node, hash_bucket(patch_vport->peer_name));
 191
 192         rcu_assign_pointer(patch_vport->peer, vport_locate(patch_vport->peer_name));
 193         update_peers(patch_vport->name, vport);
 194
 195         return 0;
 196 }
 197
 198 static int
 199 patch_detach(struct vport *vport)
 200 {
 201         struct patch_vport *patch_vport = patch_vport_priv(vport);
 202
 203         update_peers(patch_vport->name, NULL);
 204         rcu_assign_pointer(patch_vport->peer, NULL);
 205
 206         hlist_del(&patch_vport->hash_node);
 207
 208         return 0;
 209 }
 210
 211 static int
 212 patch_set_mtu(struct vport *vport, int mtu)
 213 {
 214         struct patch_vport *patch_vport = patch_vport_priv(vport);
 215         struct device_config *devconf;
 216
 217         devconf = kmemdup(patch_vport->devconf, sizeof(struct device_config), GFP_KERNEL);
 218         if (!devconf)
 219                 return -ENOMEM;
 220
 221         devconf->mtu = mtu;
 222         assign_config_rcu(vport, devconf);
 223
 224         return 0;
 225 }
 226
 227 static int
 228 patch_set_addr(struct vport *vport, const unsigned char *addr)
 229 {
 230         struct patch_vport *patch_vport = patch_vport_priv(vport);
 231         struct device_config *devconf;
 232
 233         devconf = kmemdup(patch_vport->devconf, sizeof(struct device_config), GFP_KERNEL);
 234         if (!devconf)
 235                 return -ENOMEM;
 236
 237         memcpy(devconf->eth_addr, addr, ETH_ALEN);
 238         assign_config_rcu(vport, devconf);
 239
 240         return 0;
 241 }
 242
 243
 244 static const char *
 245 patch_get_name(const struct vport *vport)
 246 {
 247         const struct patch_vport *patch_vport = patch_vport_priv(vport);
 248         return patch_vport->name;
 249 }
 250
 251 static const unsigned char *
 252 patch_get_addr(const struct vport *vport)
 253 {
 254         const struct patch_vport *patch_vport = patch_vport_priv(vport);
 255         return rcu_dereference(patch_vport->devconf)->eth_addr;
 256 }
 257
 258 static int
 259 patch_get_mtu(const struct vport *vport)
 260 {
 261         const struct patch_vport *patch_vport = patch_vport_priv(vport);
 262         return rcu_dereference(patch_vport->devconf)->mtu;
 263 }
 264
 265 static int
 266 patch_send(struct vport *vport, struct sk_buff *skb)
 267 {
 268         struct patch_vport *patch_vport = patch_vport_priv(vport);
 269         struct vport *peer = rcu_dereference(patch_vport->peer);
 270         int skb_len = skb->len;
 271
 272         if (!peer) {
 273                 kfree_skb(skb);
 274                 vport_record_error(vport, VPORT_E_TX_DROPPED);
 275
 276                 return 0;
 277         }
 278
 279         vport_receive(peer, skb);
 280         return skb_len;
 281 }
 282
 283 struct vport_ops patch_vport_ops = {
 284         .type           = "patch",
 285         .flags          = VPORT_F_GEN_STATS,
 286         .init           = patch_init,
 287         .exit           = patch_exit,
 288         .create         = patch_create,
 289         .modify         = patch_modify,
 290         .destroy        = patch_destroy,
 291         .attach         = patch_attach,
 292         .detach         = patch_detach,
 293         .set_mtu        = patch_set_mtu,
 294         .set_addr       = patch_set_addr,
 295         .get_name       = patch_get_name,
 296         .get_addr       = patch_get_addr,
 297         .get_dev_flags  = vport_gen_get_dev_flags,
 298         .is_running     = vport_gen_is_running,
 299         .get_operstate  = vport_gen_get_operstate,
 300         .get_mtu        = patch_get_mtu,
 301         .send           = patch_send,
 302 };