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 __user *uconfig)
  87 {
  88         struct patch_vport *patch_vport = patch_vport_priv(vport);
  89         char peer_name[IFNAMSIZ];
  90         int retval;
  91
  92         retval = strncpy_from_user(peer_name, uconfig, IFNAMSIZ);
  93         if (retval < 0)
  94                 return -EFAULT;
  95         else if (retval >= IFNAMSIZ)
  96                 return -ENAMETOOLONG;
  97
  98         if (!strcmp(patch_vport->name, peer_name))
  99                 return -EINVAL;
 100
 101         strcpy(patch_vport->peer_name, peer_name);
 102
 103         if (vport_get_dp_port(vport)) {
 104                 hlist_del(&patch_vport->hash_node);
 105                 rcu_assign_pointer(patch_vport->peer, vport_locate(patch_vport->peer_name));
 106                 hlist_add_head(&patch_vport->hash_node, hash_bucket(patch_vport->peer_name));
 107         }
 108
 109         return 0;
 110 }
 111
 112 static struct vport *patch_create(const char *name, const void __user *config)
 113 {
 114         struct vport *vport;
 115         struct patch_vport *patch_vport;
 116         int err;
 117
 118         vport = vport_alloc(sizeof(struct patch_vport), &patch_vport_ops);
 119         if (IS_ERR(vport)) {
 120                 err = PTR_ERR(vport);
 121                 goto error;
 122         }
 123
 124         patch_vport = patch_vport_priv(vport);
 125
 126         strcpy(patch_vport->name, name);
 127
 128         err = set_config(vport, config);
 129         if (err)
 130                 goto error_free_vport;
 131
 132         patch_vport->devconf = kmalloc(sizeof(struct device_config), GFP_KERNEL);
 133         if (!patch_vport->devconf) {
 134                 err = -ENOMEM;
 135                 goto error_free_vport;
 136         }
 137
 138         vport_gen_rand_ether_addr(patch_vport->devconf->eth_addr);
 139
 140     /* Make the default MTU fairly large so that it doesn't become the
 141      * bottleneck on systems using jumbo frames. */
 142         patch_vport->devconf->mtu = 65535;
 143
 144         return vport;
 145
 146 error_free_vport:
 147         vport_free(vport);
 148 error:
 149         return ERR_PTR(err);
 150 }
 151
 152 static int patch_modify(struct vport *vport, const void __user *config)
 153 {
 154         return set_config(vport, config);
 155 }
 156
 157 static int patch_destroy(struct vport *vport)
 158 {
 159         struct patch_vport *patch_vport = patch_vport_priv(vport);
 160
 161         kfree(patch_vport->devconf);
 162         vport_free(vport);
 163
 164         return 0;
 165 }
 166
 167 static void update_peers(const char *name, struct vport *vport)
 168 {
 169         struct hlist_head *bucket = hash_bucket(name);
 170         struct patch_vport *peer_vport;
 171         struct hlist_node *node;
 172
 173         hlist_for_each_entry(peer_vport, node, bucket, hash_node)
 174                 if (!strcmp(peer_vport->peer_name, name))
 175                         rcu_assign_pointer(peer_vport->peer, vport);
 176 }
 177
 178 static int patch_attach(struct vport *vport)
 179 {
 180         struct patch_vport *patch_vport = patch_vport_priv(vport);
 181
 182         hlist_add_head(&patch_vport->hash_node, hash_bucket(patch_vport->peer_name));
 183
 184         rcu_assign_pointer(patch_vport->peer, vport_locate(patch_vport->peer_name));
 185         update_peers(patch_vport->name, vport);
 186
 187         return 0;
 188 }
 189
 190 static int patch_detach(struct vport *vport)
 191 {
 192         struct patch_vport *patch_vport = patch_vport_priv(vport);
 193
 194         update_peers(patch_vport->name, NULL);
 195         rcu_assign_pointer(patch_vport->peer, NULL);
 196
 197         hlist_del(&patch_vport->hash_node);
 198
 199         return 0;
 200 }
 201
 202 static int patch_set_mtu(struct vport *vport, int mtu)
 203 {
 204         struct patch_vport *patch_vport = patch_vport_priv(vport);
 205         struct device_config *devconf;
 206
 207         devconf = kmemdup(patch_vport->devconf, sizeof(struct device_config), GFP_KERNEL);
 208         if (!devconf)
 209                 return -ENOMEM;
 210
 211         devconf->mtu = mtu;
 212         assign_config_rcu(vport, devconf);
 213
 214         return 0;
 215 }
 216
 217 static int patch_set_addr(struct vport *vport, const unsigned char *addr)
 218 {
 219         struct patch_vport *patch_vport = patch_vport_priv(vport);
 220         struct device_config *devconf;
 221
 222         devconf = kmemdup(patch_vport->devconf, sizeof(struct device_config), GFP_KERNEL);
 223         if (!devconf)
 224                 return -ENOMEM;
 225
 226         memcpy(devconf->eth_addr, addr, ETH_ALEN);
 227         assign_config_rcu(vport, devconf);
 228
 229         return 0;
 230 }
 231
 232
 233 static const char *patch_get_name(const struct vport *vport)
 234 {
 235         const struct patch_vport *patch_vport = patch_vport_priv(vport);
 236         return patch_vport->name;
 237 }
 238
 239 static const unsigned char *patch_get_addr(const struct vport *vport)
 240 {
 241         const struct patch_vport *patch_vport = patch_vport_priv(vport);
 242         return rcu_dereference(patch_vport->devconf)->eth_addr;
 243 }
 244
 245 static int patch_get_mtu(const struct vport *vport)
 246 {
 247         const struct patch_vport *patch_vport = patch_vport_priv(vport);
 248         return rcu_dereference(patch_vport->devconf)->mtu;
 249 }
 250
 251 static int patch_send(struct vport *vport, struct sk_buff *skb)
 252 {
 253         struct patch_vport *patch_vport = patch_vport_priv(vport);
 254         struct vport *peer = rcu_dereference(patch_vport->peer);
 255         int skb_len = skb->len;
 256
 257         if (!peer) {
 258                 kfree_skb(skb);
 259                 vport_record_error(vport, VPORT_E_TX_DROPPED);
 260
 261                 return 0;
 262         }
 263
 264         vport_receive(peer, skb);
 265         return skb_len;
 266 }
 267
 268 struct vport_ops patch_vport_ops = {
 269         .type           = "patch",
 270         .flags          = VPORT_F_GEN_STATS,
 271         .init           = patch_init,
 272         .exit           = patch_exit,
 273         .create         = patch_create,
 274         .modify         = patch_modify,
 275         .destroy        = patch_destroy,
 276         .attach         = patch_attach,
 277         .detach         = patch_detach,
 278         .set_mtu        = patch_set_mtu,
 279         .set_addr       = patch_set_addr,
 280         .get_name       = patch_get_name,
 281         .get_addr       = patch_get_addr,
 282         .get_dev_flags  = vport_gen_get_dev_flags,
 283         .is_running     = vport_gen_is_running,
 284         .get_operstate  = vport_gen_get_operstate,
 285         .get_mtu        = patch_get_mtu,
 286         .send           = patch_send,
 287 };