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         struct vport __rcu *peer;
  34         struct device_config __rcu *devconf;
  35 };
  36
  37 /* Protected by RTNL lock. */
  38 static struct hlist_head *peer_table;
  39 #define PEER_HASH_BUCKETS 256
  40
  41 static void update_peers(const char *name, struct vport *);
  42
  43 static inline struct patch_vport *patch_vport_priv(const struct vport *vport)
  44 {
  45         return vport_priv(vport);
  46 }
  47
  48 /* RCU callback. */
  49 static void free_config(struct rcu_head *rcu)
  50 {
  51         struct device_config *c = container_of(rcu, struct device_config, rcu);
  52         kfree(c);
  53 }
  54
  55 static void assign_config_rcu(struct vport *vport,
  56                               struct device_config *new_config)
  57 {
  58         struct patch_vport *patch_vport = patch_vport_priv(vport);
  59         struct device_config *old_config;
  60
  61         old_config = rcu_dereference(patch_vport->devconf);
  62         rcu_assign_pointer(patch_vport->devconf, new_config);
  63         call_rcu(&old_config->rcu, free_config);
  64 }
  65
  66 static struct hlist_head *hash_bucket(const char *name)
  67 {
  68         unsigned int hash = full_name_hash(name, strlen(name));
  69         return &peer_table[hash & (PEER_HASH_BUCKETS - 1)];
  70 }
  71
  72 static int patch_init(void)
  73 {
  74         peer_table = kzalloc(PEER_HASH_BUCKETS * sizeof(struct hlist_head),
  75                             GFP_KERNEL);
  76         if (!peer_table)
  77                 return -ENOMEM;
  78
  79         return 0;
  80 }
  81
  82 static void patch_exit(void)
  83 {
  84         kfree(peer_table);
  85 }
  86
  87 static int set_config(struct vport *vport, const void *config)
  88 {
  89         struct patch_vport *patch_vport = patch_vport_priv(vport);
  90         char peer_name[IFNAMSIZ];
  91
  92         strlcpy(peer_name, config, IFNAMSIZ);
  93
  94         if (!strcmp(patch_vport->name, peer_name))
  95                 return -EINVAL;
  96
  97         strcpy(patch_vport->peer_name, peer_name);
  98
  99         return 0;
 100 }
 101
 102 static struct vport *patch_create(const struct vport_parms *parms)
 103 {
 104         struct vport *vport;
 105         struct patch_vport *patch_vport;
 106         int err;
 107
 108         vport = vport_alloc(sizeof(struct patch_vport), &patch_vport_ops, parms);
 109         if (IS_ERR(vport)) {
 110                 err = PTR_ERR(vport);
 111                 goto error;
 112         }
 113
 114         patch_vport = patch_vport_priv(vport);
 115
 116         strcpy(patch_vport->name, parms->name);
 117
 118         err = set_config(vport, parms->config);
 119         if (err)
 120                 goto error_free_vport;
 121
 122         patch_vport->devconf = kmalloc(sizeof(struct device_config), GFP_KERNEL);
 123         if (!patch_vport->devconf) {
 124                 err = -ENOMEM;
 125                 goto error_free_vport;
 126         }
 127
 128         vport_gen_rand_ether_addr(patch_vport->devconf->eth_addr);
 129
 130         /* Make the default MTU fairly large so that it doesn't become the
 131          * bottleneck on systems using jumbo frames. */
 132         patch_vport->devconf->mtu = 65535;
 133
 134         hlist_add_head(&patch_vport->hash_node, hash_bucket(patch_vport->peer_name));
 135
 136         rcu_assign_pointer(patch_vport->peer, vport_locate(patch_vport->peer_name));
 137         update_peers(patch_vport->name, vport);
 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         int err = set_config(vport, port->config);
 150         if (!err) {
 151                 struct patch_vport *patch_vport = patch_vport_priv(vport);
 152
 153                 hlist_del(&patch_vport->hash_node);
 154                 rcu_assign_pointer(patch_vport->peer, vport_locate(patch_vport->peer_name));
 155                 hlist_add_head(&patch_vport->hash_node, hash_bucket(patch_vport->peer_name));
 156         }
 157         return err;
 158 }
 159
 160 static void free_port_rcu(struct rcu_head *rcu)
 161 {
 162         struct patch_vport *patch_vport = container_of(rcu,
 163                                                       struct patch_vport, rcu);
 164
 165         kfree(patch_vport->devconf);
 166         vport_free(vport_from_priv(patch_vport));
 167 }
 168
 169 static int patch_destroy(struct vport *vport)
 170 {
 171         struct patch_vport *patch_vport = patch_vport_priv(vport);
 172
 173         update_peers(patch_vport->name, NULL);
 174         hlist_del(&patch_vport->hash_node);
 175         call_rcu(&patch_vport->rcu, free_port_rcu);
 176
 177         return 0;
 178 }
 179
 180 static void update_peers(const char *name, struct vport *vport)
 181 {
 182         struct hlist_head *bucket = hash_bucket(name);
 183         struct patch_vport *peer_vport;
 184         struct hlist_node *node;
 185
 186         hlist_for_each_entry(peer_vport, node, bucket, hash_node)
 187                 if (!strcmp(peer_vport->peer_name, name))
 188                         rcu_assign_pointer(peer_vport->peer, vport);
 189 }
 190
 191 static int patch_set_mtu(struct vport *vport, int mtu)
 192 {
 193         struct patch_vport *patch_vport = patch_vport_priv(vport);
 194         struct device_config *devconf;
 195
 196         devconf = kmemdup(patch_vport->devconf, sizeof(struct device_config), GFP_KERNEL);
 197         if (!devconf)
 198                 return -ENOMEM;
 199
 200         devconf->mtu = mtu;
 201         assign_config_rcu(vport, devconf);
 202
 203         return 0;
 204 }
 205
 206 static int patch_set_addr(struct vport *vport, const unsigned char *addr)
 207 {
 208         struct patch_vport *patch_vport = patch_vport_priv(vport);
 209         struct device_config *devconf;
 210
 211         devconf = kmemdup(patch_vport->devconf, sizeof(struct device_config), GFP_KERNEL);
 212         if (!devconf)
 213                 return -ENOMEM;
 214
 215         memcpy(devconf->eth_addr, addr, ETH_ALEN);
 216         assign_config_rcu(vport, devconf);
 217
 218         return 0;
 219 }
 220
 221
 222 static const char *patch_get_name(const struct vport *vport)
 223 {
 224         const struct patch_vport *patch_vport = patch_vport_priv(vport);
 225         return patch_vport->name;
 226 }
 227
 228 static const unsigned char *patch_get_addr(const struct vport *vport)
 229 {
 230         const struct patch_vport *patch_vport = patch_vport_priv(vport);
 231         return rcu_dereference(patch_vport->devconf)->eth_addr;
 232 }
 233
 234 static int patch_get_mtu(const struct vport *vport)
 235 {
 236         const struct patch_vport *patch_vport = patch_vport_priv(vport);
 237         return rcu_dereference(patch_vport->devconf)->mtu;
 238 }
 239
 240 static int patch_send(struct vport *vport, struct sk_buff *skb)
 241 {
 242         struct patch_vport *patch_vport = patch_vport_priv(vport);
 243         struct vport *peer = rcu_dereference(patch_vport->peer);
 244         int skb_len = skb->len;
 245
 246         if (!peer) {
 247                 kfree_skb(skb);
 248                 vport_record_error(vport, VPORT_E_TX_DROPPED);
 249
 250                 return 0;
 251         }
 252
 253         vport_receive(peer, skb);
 254         return skb_len;
 255 }
 256
 257 const struct vport_ops patch_vport_ops = {
 258         .type           = "patch",
 259         .flags          = VPORT_F_GEN_STATS,
 260         .init           = patch_init,
 261         .exit           = patch_exit,
 262         .create         = patch_create,
 263         .modify         = patch_modify,
 264         .destroy        = patch_destroy,
 265         .set_mtu        = patch_set_mtu,
 266         .set_addr       = patch_set_addr,
 267         .get_name       = patch_get_name,
 268         .get_addr       = patch_get_addr,
 269         .get_dev_flags  = vport_gen_get_dev_flags,
 270         .is_running     = vport_gen_is_running,
 271         .get_operstate  = vport_gen_get_operstate,
 272         .get_mtu        = patch_get_mtu,
 273         .send           = patch_send,
 274 };