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 *patch_vport_priv(const struct vport *vport)
  43 {
  44         return vport_priv(vport);
  45 }
  46
  47 /* RCU callback. */
  48 static void free_config(struct rcu_head *rcu)
  49 {
  50         struct device_config *c = container_of(rcu, struct device_config, rcu);
  51         kfree(c);
  52 }
  53
  54 static void assign_config_rcu(struct vport *vport,
  55                               struct device_config *new_config)
  56 {
  57         struct patch_vport *patch_vport = patch_vport_priv(vport);
  58         struct device_config *old_config;
  59
  60         old_config = rcu_dereference(patch_vport->devconf);
  61         rcu_assign_pointer(patch_vport->devconf, new_config);
  62         call_rcu(&old_config->rcu, free_config);
  63 }
  64
  65 static struct hlist_head *hash_bucket(const char *name)
  66 {
  67         unsigned int hash = full_name_hash(name, strlen(name));
  68         return &peer_table[hash & (PEER_HASH_BUCKETS - 1)];
  69 }
  70
  71 static int patch_init(void)
  72 {
  73         peer_table = kzalloc(PEER_HASH_BUCKETS * sizeof(struct hlist_head),
  74                             GFP_KERNEL);
  75         if (!peer_table)
  76                 return -ENOMEM;
  77
  78         return 0;
  79 }
  80
  81 static void patch_exit(void)
  82 {
  83         kfree(peer_table);
  84 }
  85
  86 static int set_config(struct vport *vport, const void *config)
  87 {
  88         struct patch_vport *patch_vport = patch_vport_priv(vport);
  89         char peer_name[IFNAMSIZ];
  90
  91         strlcpy(peer_name, config, IFNAMSIZ);
  92
  93         if (!strcmp(patch_vport->name, peer_name))
  94                 return -EINVAL;
  95
  96         strcpy(patch_vport->peer_name, peer_name);
  97
  98         if (vport_get_dp_port(vport)) {
  99                 hlist_del(&patch_vport->hash_node);
 100                 rcu_assign_pointer(patch_vport->peer, vport_locate(patch_vport->peer_name));
 101                 hlist_add_head(&patch_vport->hash_node, hash_bucket(patch_vport->peer_name));
 102         }
 103
 104         return 0;
 105 }
 106
 107 static struct vport *patch_create(const struct vport_parms *parms)
 108 {
 109         struct vport *vport;
 110         struct patch_vport *patch_vport;
 111         int err;
 112
 113         vport = vport_alloc(sizeof(struct patch_vport), &patch_vport_ops);
 114         if (IS_ERR(vport)) {
 115                 err = PTR_ERR(vport);
 116                 goto error;
 117         }
 118
 119         patch_vport = patch_vport_priv(vport);
 120
 121         strcpy(patch_vport->name, parms->name);
 122
 123         err = set_config(vport, parms->config);
 124         if (err)
 125                 goto error_free_vport;
 126
 127         patch_vport->devconf = kmalloc(sizeof(struct device_config), GFP_KERNEL);
 128         if (!patch_vport->devconf) {
 129                 err = -ENOMEM;
 130                 goto error_free_vport;
 131         }
 132
 133         vport_gen_rand_ether_addr(patch_vport->devconf->eth_addr);
 134
 135     /* Make the default MTU fairly large so that it doesn't become the
 136      * bottleneck on systems using jumbo frames. */
 137         patch_vport->devconf->mtu = 65535;
 138
 139         return vport;
 140
 141 error_free_vport:
 142         vport_free(vport);
 143 error:
 144         return ERR_PTR(err);
 145 }
 146
 147 static int patch_modify(struct vport *vport, struct odp_port *port)
 148 {
 149         return set_config(vport, port->config);
 150 }
 151
 152 static int patch_destroy(struct vport *vport)
 153 {
 154         struct patch_vport *patch_vport = patch_vport_priv(vport);
 155
 156         kfree(patch_vport->devconf);
 157         vport_free(vport);
 158
 159         return 0;
 160 }
 161
 162 static void update_peers(const char *name, struct vport *vport)
 163 {
 164         struct hlist_head *bucket = hash_bucket(name);
 165         struct patch_vport *peer_vport;
 166         struct hlist_node *node;
 167
 168         hlist_for_each_entry(peer_vport, node, bucket, hash_node)
 169                 if (!strcmp(peer_vport->peer_name, name))
 170                         rcu_assign_pointer(peer_vport->peer, vport);
 171 }
 172
 173 static int patch_attach(struct vport *vport)
 174 {
 175         struct patch_vport *patch_vport = patch_vport_priv(vport);
 176
 177         hlist_add_head(&patch_vport->hash_node, hash_bucket(patch_vport->peer_name));
 178
 179         rcu_assign_pointer(patch_vport->peer, vport_locate(patch_vport->peer_name));
 180         update_peers(patch_vport->name, vport);
 181
 182         return 0;
 183 }
 184
 185 static int patch_detach(struct vport *vport)
 186 {
 187         struct patch_vport *patch_vport = patch_vport_priv(vport);
 188
 189         update_peers(patch_vport->name, NULL);
 190         rcu_assign_pointer(patch_vport->peer, NULL);
 191
 192         hlist_del(&patch_vport->hash_node);
 193
 194         return 0;
 195 }
 196
 197 static int patch_set_mtu(struct vport *vport, int mtu)
 198 {
 199         struct patch_vport *patch_vport = patch_vport_priv(vport);
 200         struct device_config *devconf;
 201
 202         devconf = kmemdup(patch_vport->devconf, sizeof(struct device_config), GFP_KERNEL);
 203         if (!devconf)
 204                 return -ENOMEM;
 205
 206         devconf->mtu = mtu;
 207         assign_config_rcu(vport, devconf);
 208
 209         return 0;
 210 }
 211
 212 static int patch_set_addr(struct vport *vport, const unsigned char *addr)
 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         memcpy(devconf->eth_addr, addr, ETH_ALEN);
 222         assign_config_rcu(vport, devconf);
 223
 224         return 0;
 225 }
 226
 227
 228 static const char *patch_get_name(const struct vport *vport)
 229 {
 230         const struct patch_vport *patch_vport = patch_vport_priv(vport);
 231         return patch_vport->name;
 232 }
 233
 234 static const unsigned char *patch_get_addr(const struct vport *vport)
 235 {
 236         const struct patch_vport *patch_vport = patch_vport_priv(vport);
 237         return rcu_dereference(patch_vport->devconf)->eth_addr;
 238 }
 239
 240 static int patch_get_mtu(const struct vport *vport)
 241 {
 242         const struct patch_vport *patch_vport = patch_vport_priv(vport);
 243         return rcu_dereference(patch_vport->devconf)->mtu;
 244 }
 245
 246 static int patch_send(struct vport *vport, struct sk_buff *skb)
 247 {
 248         struct patch_vport *patch_vport = patch_vport_priv(vport);
 249         struct vport *peer = rcu_dereference(patch_vport->peer);
 250         int skb_len = skb->len;
 251
 252         if (!peer) {
 253                 kfree_skb(skb);
 254                 vport_record_error(vport, VPORT_E_TX_DROPPED);
 255
 256                 return 0;
 257         }
 258
 259         vport_receive(peer, skb);
 260         return skb_len;
 261 }
 262
 263 const struct vport_ops patch_vport_ops = {
 264         .type           = "patch",
 265         .flags          = VPORT_F_GEN_STATS,
 266         .init           = patch_init,
 267         .exit           = patch_exit,
 268         .create         = patch_create,
 269         .modify         = patch_modify,
 270         .destroy        = patch_destroy,
 271         .attach         = patch_attach,
 272         .detach         = patch_detach,
 273         .set_mtu        = patch_set_mtu,
 274         .set_addr       = patch_set_addr,
 275         .get_name       = patch_get_name,
 276         .get_addr       = patch_get_addr,
 277         .get_dev_flags  = vport_gen_get_dev_flags,
 278         .is_running     = vport_gen_is_running,
 279         .get_operstate  = vport_gen_get_operstate,
 280         .get_mtu        = patch_get_mtu,
 281         .send           = patch_send,
 282 };