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