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         struct rcu_head rcu;
  26
  27         char name[IFNAMSIZ];
  28
  29         /* Protected by RTNL lock. */
  30         char peer_name[IFNAMSIZ];
  31         struct hlist_node hash_node;
  32
  33         /* Protected by RCU. */
  34         struct vport *peer;
  35
  36         /* Protected by RCU. */
  37         struct device_config *devconf;
  38 };
  39
  40 /* Protected by RTNL lock. */
  41 static struct hlist_head *peer_table;
  42 #define PEER_HASH_BUCKETS 256
  43
  44 static void update_peers(const char *name, struct vport *);
  45
  46 static inline struct patch_vport *patch_vport_priv(const struct vport *vport)
  47 {
  48         return vport_priv(vport);
  49 }
  50
  51 /* RCU callback. */
  52 static void 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 assign_config_rcu(struct vport *vport,
  59                               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 *hash_bucket(const char *name)
  70 {
  71         unsigned int hash = full_name_hash(name, strlen(name));
  72         return &peer_table[hash & (PEER_HASH_BUCKETS - 1)];
  73 }
  74
  75 static int 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 patch_exit(void)
  86 {
  87         kfree(peer_table);
  88 }
  89
  90 static int set_config(struct vport *vport, const void *config)
  91 {
  92         struct patch_vport *patch_vport = patch_vport_priv(vport);
  93         char peer_name[IFNAMSIZ];
  94
  95         strlcpy(peer_name, config, IFNAMSIZ);
  96
  97         if (!strcmp(patch_vport->name, peer_name))
  98                 return -EINVAL;
  99
 100         strcpy(patch_vport->peer_name, peer_name);
 101
 102         return 0;
 103 }
 104
 105 static struct vport *patch_create(const struct vport_parms *parms)
 106 {
 107         struct vport *vport;
 108         struct patch_vport *patch_vport;
 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         err = set_config(vport, parms->config);
 122         if (err)
 123                 goto error_free_vport;
 124
 125         patch_vport->devconf = kmalloc(sizeof(struct device_config), GFP_KERNEL);
 126         if (!patch_vport->devconf) {
 127                 err = -ENOMEM;
 128                 goto error_free_vport;
 129         }
 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         hlist_add_head(&patch_vport->hash_node, hash_bucket(patch_vport->peer_name));
 138
 139         rcu_assign_pointer(patch_vport->peer, vport_locate(patch_vport->peer_name));
 140         update_peers(patch_vport->name, vport);
 141
 142         return vport;
 143
 144 error_free_vport:
 145         vport_free(vport);
 146 error:
 147         return ERR_PTR(err);
 148 }
 149
 150 static int patch_modify(struct vport *vport, struct odp_port *port)
 151 {
 152         int err = set_config(vport, port->config);
 153         if (!err) {
 154                 struct patch_vport *patch_vport = patch_vport_priv(vport);
 155
 156                 hlist_del(&patch_vport->hash_node);
 157                 rcu_assign_pointer(patch_vport->peer, vport_locate(patch_vport->peer_name));
 158                 hlist_add_head(&patch_vport->hash_node, hash_bucket(patch_vport->peer_name));
 159         }
 160         return err;
 161 }
 162
 163 static void free_port_rcu(struct rcu_head *rcu)
 164 {
 165         struct patch_vport *patch_vport = container_of(rcu,
 166                                                       struct patch_vport, rcu);
 167
 168         kfree(patch_vport->devconf);
 169         vport_free(vport_from_priv(patch_vport));
 170 }
 171
 172 static int patch_destroy(struct vport *vport)
 173 {
 174         struct patch_vport *patch_vport = patch_vport_priv(vport);
 175
 176         update_peers(patch_vport->name, NULL);
 177         hlist_del(&patch_vport->hash_node);
 178         call_rcu(&patch_vport->rcu, free_port_rcu);
 179
 180         return 0;
 181 }
 182
 183 static void update_peers(const char *name, struct vport *vport)
 184 {
 185         struct hlist_head *bucket = hash_bucket(name);
 186         struct patch_vport *peer_vport;
 187         struct hlist_node *node;
 188
 189         hlist_for_each_entry(peer_vport, node, bucket, hash_node)
 190                 if (!strcmp(peer_vport->peer_name, name))
 191                         rcu_assign_pointer(peer_vport->peer, vport);
 192 }
 193
 194 static int patch_set_mtu(struct vport *vport, int mtu)
 195 {
 196         struct patch_vport *patch_vport = patch_vport_priv(vport);
 197         struct device_config *devconf;
 198
 199         devconf = kmemdup(patch_vport->devconf, sizeof(struct device_config), GFP_KERNEL);
 200         if (!devconf)
 201                 return -ENOMEM;
 202
 203         devconf->mtu = mtu;
 204         assign_config_rcu(vport, devconf);
 205
 206         return 0;
 207 }
 208
 209 static int patch_set_addr(struct vport *vport, const unsigned char *addr)
 210 {
 211         struct patch_vport *patch_vport = patch_vport_priv(vport);
 212         struct device_config *devconf;
 213
 214         devconf = kmemdup(patch_vport->devconf, sizeof(struct device_config), GFP_KERNEL);
 215         if (!devconf)
 216                 return -ENOMEM;
 217
 218         memcpy(devconf->eth_addr, addr, ETH_ALEN);
 219         assign_config_rcu(vport, devconf);
 220
 221         return 0;
 222 }
 223
 224
 225 static const char *patch_get_name(const struct vport *vport)
 226 {
 227         const struct patch_vport *patch_vport = patch_vport_priv(vport);
 228         return patch_vport->name;
 229 }
 230
 231 static const unsigned char *patch_get_addr(const struct vport *vport)
 232 {
 233         const struct patch_vport *patch_vport = patch_vport_priv(vport);
 234         return rcu_dereference(patch_vport->devconf)->eth_addr;
 235 }
 236
 237 static int patch_get_mtu(const struct vport *vport)
 238 {
 239         const struct patch_vport *patch_vport = patch_vport_priv(vport);
 240         return rcu_dereference(patch_vport->devconf)->mtu;
 241 }
 242
 243 static int patch_send(struct vport *vport, struct sk_buff *skb)
 244 {
 245         struct patch_vport *patch_vport = patch_vport_priv(vport);
 246         struct vport *peer = rcu_dereference(patch_vport->peer);
 247         int skb_len = skb->len;
 248
 249         if (!peer) {
 250                 kfree_skb(skb);
 251                 vport_record_error(vport, VPORT_E_TX_DROPPED);
 252
 253                 return 0;
 254         }
 255
 256         vport_receive(peer, skb);
 257         return skb_len;
 258 }
 259
 260 const struct vport_ops patch_vport_ops = {
 261         .type           = "patch",
 262         .flags          = VPORT_F_GEN_STATS,
 263         .init           = patch_init,
 264         .exit           = patch_exit,
 265         .create         = patch_create,
 266         .modify         = patch_modify,
 267         .destroy        = patch_destroy,
 268         .set_mtu        = patch_set_mtu,
 269         .set_addr       = patch_set_addr,
 270         .get_name       = patch_get_name,
 271         .get_addr       = patch_get_addr,
 272         .get_dev_flags  = vport_gen_get_dev_flags,
 273         .is_running     = vport_gen_is_running,
 274         .get_operstate  = vport_gen_get_operstate,
 275         .get_mtu        = patch_get_mtu,
 276         .send           = patch_send,
 277 };