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 struct vport_ops patch_vport_ops;
  39
  40 /* Protected by RTNL lock. */
  41 static struct hlist_head *peer_table;
  42 #define PEER_HASH_BUCKETS 256
  43
  44 static inline struct patch_vport *
  45 patch_vport_priv(const struct vport *vport)
  46 {
  47         return vport_priv(vport);
  48 }
  49
  50 /* RCU callback. */
  51 static void
  52 free_config(struct rcu_head *rcu)
  53 {
  54         struct device_config *c = container_of(rcu, struct device_config, rcu);
  55         kfree(c);
  56 }
  57
  58 static void
  59 assign_config_rcu(struct vport *vport, struct device_config *new_config)
  60 {
  61         struct patch_vport *patch_vport = patch_vport_priv(vport);
  62         struct device_config *old_config;
  63
  64         old_config = rcu_dereference(patch_vport->devconf);
  65         rcu_assign_pointer(patch_vport->devconf, new_config);
  66         call_rcu(&old_config->rcu, free_config);
  67 }
  68
  69 static struct hlist_head *
  70 hash_bucket(const char *name)
  71 {
  72         unsigned int hash = full_name_hash(name, strlen(name));
  73         return &peer_table[hash & (PEER_HASH_BUCKETS - 1)];
  74 }
  75
  76 static int
  77 patch_init(void)
  78 {
  79         peer_table = kzalloc(PEER_HASH_BUCKETS * sizeof(struct hlist_head),
  80                             GFP_KERNEL);
  81         if (!peer_table)
  82                 return -ENOMEM;
  83
  84         return 0;
  85 }
  86
  87 static void
  88 patch_exit(void)
  89 {
  90         kfree(peer_table);
  91 }
  92
  93 static int
  94 set_config(struct vport *vport, const void __user *uconfig)
  95 {
  96         struct patch_vport *patch_vport = patch_vport_priv(vport);
  97         char peer_name[IFNAMSIZ];
  98         int retval;
  99
 100         retval = strncpy_from_user(peer_name, uconfig, IFNAMSIZ);
 101         if (retval < 0)
 102                 return -EFAULT;
 103         else if (retval >= IFNAMSIZ)
 104                 return -ENAMETOOLONG;
 105
 106         if (!strcmp(patch_vport->name, peer_name))
 107                 return -EINVAL;
 108
 109         strcpy(patch_vport->peer_name, peer_name);
 110
 111         if (vport_get_dp_port(vport)) {
 112                 hlist_del(&patch_vport->hash_node);
 113                 rcu_assign_pointer(patch_vport->peer, vport_locate(patch_vport->peer_name));
 114                 hlist_add_head(&patch_vport->hash_node, hash_bucket(patch_vport->peer_name));
 115         }
 116
 117         return 0;
 118 }
 119
 120 static struct vport *
 121 patch_create(const char *name, const void __user *config)
 122 {
 123         struct vport *vport;
 124         struct patch_vport *patch_vport;
 125         int err;
 126
 127         vport = vport_alloc(sizeof(struct patch_vport), &patch_vport_ops);
 128         if (IS_ERR(vport)) {
 129                 err = PTR_ERR(vport);
 130                 goto error;
 131         }
 132
 133         patch_vport = patch_vport_priv(vport);
 134
 135         strcpy(patch_vport->name, name);
 136
 137         err = set_config(vport, config);
 138         if (err)
 139                 goto error_free_vport;
 140
 141         patch_vport->devconf = kmalloc(sizeof(struct device_config), GFP_KERNEL);
 142         if (!patch_vport->devconf) {
 143                 err = -ENOMEM;
 144                 goto error_free_vport;
 145         }
 146
 147         vport_gen_rand_ether_addr(patch_vport->devconf->eth_addr);
 148         patch_vport->devconf->mtu = ETH_DATA_LEN;
 149
 150         return vport;
 151
 152 error_free_vport:
 153         vport_free(vport);
 154 error:
 155         return ERR_PTR(err);
 156 }
 157
 158 static int
 159 patch_modify(struct vport *vport, const void __user *config)
 160 {
 161         return set_config(vport, config);
 162 }
 163
 164 static int
 165 patch_destroy(struct vport *vport)
 166 {
 167         struct patch_vport *patch_vport = patch_vport_priv(vport);
 168
 169         kfree(patch_vport->devconf);
 170         vport_free(vport);
 171
 172         return 0;
 173 }
 174
 175 static void
 176 update_peers(const char *name, struct vport *vport)
 177 {
 178         struct hlist_head *bucket = hash_bucket(name);
 179         struct patch_vport *peer_vport;
 180         struct hlist_node *node;
 181
 182         hlist_for_each_entry(peer_vport, node, bucket, hash_node)
 183                 if (!strcmp(peer_vport->peer_name, name))
 184                         rcu_assign_pointer(peer_vport->peer, vport);
 185 }
 186
 187 static int
 188 patch_attach(struct vport *vport)
 189 {
 190         struct patch_vport *patch_vport = patch_vport_priv(vport);
 191
 192         hlist_add_head(&patch_vport->hash_node, hash_bucket(patch_vport->peer_name));
 193
 194         rcu_assign_pointer(patch_vport->peer, vport_locate(patch_vport->peer_name));
 195         update_peers(patch_vport->name, vport);
 196
 197         return 0;
 198 }
 199
 200 static int
 201 patch_detach(struct vport *vport)
 202 {
 203         struct patch_vport *patch_vport = patch_vport_priv(vport);
 204
 205         update_peers(patch_vport->name, NULL);
 206         rcu_assign_pointer(patch_vport->peer, NULL);
 207
 208         hlist_del(&patch_vport->hash_node);
 209
 210         return 0;
 211 }
 212
 213 static int
 214 patch_set_mtu(struct vport *vport, int mtu)
 215 {
 216         struct patch_vport *patch_vport = patch_vport_priv(vport);
 217         struct device_config *devconf;
 218
 219         devconf = kmemdup(patch_vport->devconf, sizeof(struct device_config), GFP_KERNEL);
 220         if (!devconf)
 221                 return -ENOMEM;
 222
 223         devconf->mtu = mtu;
 224         assign_config_rcu(vport, devconf);
 225
 226         return 0;
 227 }
 228
 229 static int
 230 patch_set_addr(struct vport *vport, const unsigned char *addr)
 231 {
 232         struct patch_vport *patch_vport = patch_vport_priv(vport);
 233         struct device_config *devconf;
 234
 235         devconf = kmemdup(patch_vport->devconf, sizeof(struct device_config), GFP_KERNEL);
 236         if (!devconf)
 237                 return -ENOMEM;
 238
 239         memcpy(devconf->eth_addr, addr, ETH_ALEN);
 240         assign_config_rcu(vport, devconf);
 241
 242         return 0;
 243 }
 244
 245
 246 static const char *
 247 patch_get_name(const struct vport *vport)
 248 {
 249         const struct patch_vport *patch_vport = patch_vport_priv(vport);
 250         return patch_vport->name;
 251 }
 252
 253 static const unsigned char *
 254 patch_get_addr(const struct vport *vport)
 255 {
 256         const struct patch_vport *patch_vport = patch_vport_priv(vport);
 257         return rcu_dereference(patch_vport->devconf)->eth_addr;
 258 }
 259
 260 static int
 261 patch_get_mtu(const struct vport *vport)
 262 {
 263         const struct patch_vport *patch_vport = patch_vport_priv(vport);
 264         return rcu_dereference(patch_vport->devconf)->mtu;
 265 }
 266
 267 static int
 268 patch_send(struct vport *vport, struct sk_buff *skb)
 269 {
 270         struct patch_vport *patch_vport = patch_vport_priv(vport);
 271         struct vport *peer = rcu_dereference(patch_vport->peer);
 272         int skb_len = skb->len;
 273
 274         if (!peer) {
 275                 kfree_skb(skb);
 276                 vport_record_error(vport, VPORT_E_TX_DROPPED);
 277
 278                 return 0;
 279         }
 280
 281         vport_receive(peer, skb);
 282         return skb_len;
 283 }
 284
 285 struct vport_ops patch_vport_ops = {
 286         .type           = "patch",
 287         .flags          = VPORT_F_GEN_STATS,
 288         .init           = patch_init,
 289         .exit           = patch_exit,
 290         .create         = patch_create,
 291         .modify         = patch_modify,
 292         .destroy        = patch_destroy,
 293         .attach         = patch_attach,
 294         .detach         = patch_detach,
 295         .set_mtu        = patch_set_mtu,
 296         .set_addr       = patch_set_addr,
 297         .get_name       = patch_get_name,
 298         .get_addr       = patch_get_addr,
 299         .get_dev_flags  = vport_gen_get_dev_flags,
 300         .is_running     = vport_gen_is_running,
 301         .get_operstate  = vport_gen_get_operstate,
 302         .get_mtu        = patch_get_mtu,
 303         .send           = patch_send,
 304 };