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 #include <linux/rtnetlink.h>
  13
  14 #include "datapath.h"
  15 #include "vport.h"
  16 #include "vport-generic.h"
  17
  18 struct device_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 device_config __rcu *devconf;
  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 device_config *c = container_of(rcu, struct device_config, rcu);
  53         kfree(c);
  54 }
  55
  56 static void assign_config_rcu(struct vport *vport,
  57                               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 = rtnl_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 *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 int set_config(struct vport *vport, const void *config,
  89                         struct device_config *devconf)
  90 {
  91         struct patch_vport *patch_vport = patch_vport_priv(vport);
  92         char peer_name[IFNAMSIZ];
  93
  94         strlcpy(peer_name, config, IFNAMSIZ);
  95
  96         if (!strcmp(patch_vport->name, peer_name))
  97                 return -EINVAL;
  98
  99         strcpy(devconf->peer_name, peer_name);
 100
 101         return 0;
 102 }
 103
 104 static struct vport *patch_create(const struct vport_parms *parms)
 105 {
 106         struct vport *vport;
 107         struct patch_vport *patch_vport;
 108         const char *peer_name;
 109         int err;
 110
 111         vport = vport_alloc(sizeof(struct patch_vport), &patch_vport_ops, parms);
 112         if (IS_ERR(vport)) {
 113                 err = PTR_ERR(vport);
 114                 goto error;
 115         }
 116
 117         patch_vport = patch_vport_priv(vport);
 118
 119         strcpy(patch_vport->name, parms->name);
 120
 121         patch_vport->devconf = kmalloc(sizeof(struct device_config), GFP_KERNEL);
 122         if (!patch_vport->devconf) {
 123                 err = -ENOMEM;
 124                 goto error_free_vport;
 125         }
 126
 127         err = set_config(vport, parms->config, patch_vport->devconf);
 128         if (err)
 129                 goto error_free_devconf;
 130
 131         vport_gen_rand_ether_addr(patch_vport->devconf->eth_addr);
 132
 133         /* Make the default MTU fairly large so that it doesn't become the
 134          * bottleneck on systems using jumbo frames. */
 135         patch_vport->devconf->mtu = 65535;
 136
 137         peer_name = patch_vport->devconf->peer_name;
 138         hlist_add_head(&patch_vport->hash_node, hash_bucket(peer_name));
 139
 140         rcu_assign_pointer(patch_vport->peer, vport_locate(peer_name));
 141         update_peers(patch_vport->name, vport);
 142
 143         return vport;
 144
 145 error_free_devconf:
 146         kfree(patch_vport->devconf);
 147 error_free_vport:
 148         vport_free(vport);
 149 error:
 150         return ERR_PTR(err);
 151 }
 152
 153 static int patch_modify(struct vport *vport, struct odp_port *port)
 154 {
 155         struct patch_vport *patch_vport = patch_vport_priv(vport);
 156         struct device_config *devconf;
 157         int err;
 158
 159         devconf = kmemdup(patch_vport->devconf, sizeof(struct device_config), GFP_KERNEL);
 160         if (!devconf) {
 161                 err = -ENOMEM;
 162                 goto error;
 163         }
 164
 165         err = set_config(vport, port->config, devconf);
 166         if (err)
 167                 goto error_free;
 168
 169         assign_config_rcu(vport, devconf);
 170
 171         hlist_del(&patch_vport->hash_node);
 172
 173         rcu_assign_pointer(patch_vport->peer, vport_locate(devconf->peer_name));
 174         hlist_add_head(&patch_vport->hash_node, hash_bucket(devconf->peer_name));
 175
 176         return 0;
 177
 178 error_free:
 179         kfree(devconf);
 180 error:
 181         return err;
 182 }
 183
 184 static void free_port_rcu(struct rcu_head *rcu)
 185 {
 186         struct patch_vport *patch_vport = container_of(rcu,
 187                                                       struct patch_vport, rcu);
 188
 189         kfree(patch_vport->devconf);
 190         vport_free(vport_from_priv(patch_vport));
 191 }
 192
 193 static int patch_destroy(struct vport *vport)
 194 {
 195         struct patch_vport *patch_vport = patch_vport_priv(vport);
 196
 197         update_peers(patch_vport->name, NULL);
 198         hlist_del(&patch_vport->hash_node);
 199         call_rcu(&patch_vport->rcu, free_port_rcu);
 200
 201         return 0;
 202 }
 203
 204 static void update_peers(const char *name, struct vport *vport)
 205 {
 206         struct hlist_head *bucket = hash_bucket(name);
 207         struct patch_vport *peer_vport;
 208         struct hlist_node *node;
 209
 210         hlist_for_each_entry(peer_vport, node, bucket, hash_node) {
 211                 const char *peer_name;
 212
 213                 peer_name = rtnl_dereference(peer_vport->devconf)->peer_name;
 214                 if (!strcmp(peer_name, name))
 215                         rcu_assign_pointer(peer_vport->peer, vport);
 216         }
 217 }
 218
 219 static int patch_set_mtu(struct vport *vport, int mtu)
 220 {
 221         struct patch_vport *patch_vport = patch_vport_priv(vport);
 222         struct device_config *devconf;
 223
 224         devconf = kmemdup(patch_vport->devconf, sizeof(struct device_config), GFP_KERNEL);
 225         if (!devconf)
 226                 return -ENOMEM;
 227
 228         devconf->mtu = mtu;
 229         assign_config_rcu(vport, devconf);
 230
 231         return 0;
 232 }
 233
 234 static int patch_set_addr(struct vport *vport, const unsigned char *addr)
 235 {
 236         struct patch_vport *patch_vport = patch_vport_priv(vport);
 237         struct device_config *devconf;
 238
 239         devconf = kmemdup(patch_vport->devconf, sizeof(struct device_config), GFP_KERNEL);
 240         if (!devconf)
 241                 return -ENOMEM;
 242
 243         memcpy(devconf->eth_addr, addr, ETH_ALEN);
 244         assign_config_rcu(vport, devconf);
 245
 246         return 0;
 247 }
 248
 249
 250 static const char *patch_get_name(const struct vport *vport)
 251 {
 252         const struct patch_vport *patch_vport = patch_vport_priv(vport);
 253         return patch_vport->name;
 254 }
 255
 256 static const unsigned char *patch_get_addr(const struct vport *vport)
 257 {
 258         const struct patch_vport *patch_vport = patch_vport_priv(vport);
 259         return rcu_dereference_rtnl(patch_vport->devconf)->eth_addr;
 260 }
 261
 262 static void patch_get_config(const struct vport *vport, void *config)
 263 {
 264         const struct patch_vport *patch_vport = patch_vport_priv(vport);
 265         const char *peer_name;
 266
 267         peer_name = rcu_dereference_rtnl(patch_vport->devconf)->peer_name;
 268         strlcpy(config, peer_name, VPORT_CONFIG_SIZE);
 269 }
 270
 271 static int patch_get_mtu(const struct vport *vport)
 272 {
 273         const struct patch_vport *patch_vport = patch_vport_priv(vport);
 274         return rcu_dereference_rtnl(patch_vport->devconf)->mtu;
 275 }
 276
 277 static int patch_send(struct vport *vport, struct sk_buff *skb)
 278 {
 279         struct patch_vport *patch_vport = patch_vport_priv(vport);
 280         struct vport *peer = rcu_dereference(patch_vport->peer);
 281         int skb_len = skb->len;
 282
 283         if (!peer) {
 284                 kfree_skb(skb);
 285                 vport_record_error(vport, VPORT_E_TX_DROPPED);
 286
 287                 return 0;
 288         }
 289
 290         vport_receive(peer, skb);
 291         return skb_len;
 292 }
 293
 294 const struct vport_ops patch_vport_ops = {
 295         .type           = "patch",
 296         .flags          = VPORT_F_GEN_STATS,
 297         .init           = patch_init,
 298         .exit           = patch_exit,
 299         .create         = patch_create,
 300         .modify         = patch_modify,
 301         .destroy        = patch_destroy,
 302         .set_mtu        = patch_set_mtu,
 303         .set_addr       = patch_set_addr,
 304         .get_name       = patch_get_name,
 305         .get_addr       = patch_get_addr,
 306         .get_config     = patch_get_config,
 307         .get_dev_flags  = vport_gen_get_dev_flags,
 308         .is_running     = vport_gen_is_running,
 309         .get_operstate  = vport_gen_get_operstate,
 310         .get_mtu        = patch_get_mtu,
 311         .send           = patch_send,
 312 };