net/caif/chnl_net.c

   1 /*
   2  * Copyright (C) ST-Ericsson AB 2010
   3  * Authors:     Sjur Brendeland
   4  *              Daniel Martensson
   5  * License terms: GNU General Public License (GPL) version 2
   6  */
   7
   8 #define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
   9
  10 #include <linux/fs.h>
  11 #include <linux/hardirq.h>
  12 #include <linux/init.h>
  13 #include <linux/module.h>
  14 #include <linux/netdevice.h>
  15 #include <linux/if_ether.h>
  16 #include <linux/ip.h>
  17 #include <linux/sched.h>
  18 #include <linux/sockios.h>
  19 #include <linux/caif/if_caif.h>
  20 #include <net/rtnetlink.h>
  21 #include <net/caif/caif_layer.h>
  22 #include <net/caif/cfpkt.h>
  23 #include <net/caif/caif_dev.h>
  24
  25 /* GPRS PDP connection has MTU to 1500 */
  26 #define GPRS_PDP_MTU 1500
  27 /* 5 sec. connect timeout */
  28 #define CONNECT_TIMEOUT (5 * HZ)
  29 #define CAIF_NET_DEFAULT_QUEUE_LEN 500
  30 #define UNDEF_CONNID 0xffffffff
  31
  32 /*This list is protected by the rtnl lock. */
  33 static LIST_HEAD(chnl_net_list);
  34
  35 MODULE_LICENSE("GPL");
  36 MODULE_ALIAS_RTNL_LINK("caif");
  37
  38 enum caif_states {
  39         CAIF_CONNECTED          = 1,
  40         CAIF_CONNECTING,
  41         CAIF_DISCONNECTED,
  42         CAIF_SHUTDOWN
  43 };
  44
  45 struct chnl_net {
  46         struct cflayer chnl;
  47         struct net_device_stats stats;
  48         struct caif_connect_request conn_req;
  49         struct list_head list_field;
  50         struct net_device *netdev;
  51         char name[256];
  52         wait_queue_head_t netmgmt_wq;
  53         /* Flow status to remember and control the transmission. */
  54         bool flowenabled;
  55         enum caif_states state;
  56 };
  57
  58 static int chnl_recv_cb(struct cflayer *layr, struct cfpkt *pkt)
  59 {
  60         struct sk_buff *skb;
  61         struct chnl_net *priv;
  62         int pktlen;
  63         const u8 *ip_version;
  64         u8 buf;
  65
  66         priv = container_of(layr, struct chnl_net, chnl);
  67         if (!priv)
  68                 return -EINVAL;
  69
  70         skb = (struct sk_buff *) cfpkt_tonative(pkt);
  71
  72         /* Get length of CAIF packet. */
  73         pktlen = skb->len;
  74
  75         /* Pass some minimum information and
  76          * send the packet to the net stack.
  77          */
  78         skb->dev = priv->netdev;
  79
  80         /* check the version of IP */
  81         ip_version = skb_header_pointer(skb, 0, 1, &buf);
  82         if (!ip_version) {
  83                 kfree_skb(skb);
  84                 return -EINVAL;
  85         }
  86
  87         switch (*ip_version >> 4) {
  88         case 4:
  89                 skb->protocol = htons(ETH_P_IP);
  90                 break;
  91         case 6:
  92                 skb->protocol = htons(ETH_P_IPV6);
  93                 break;
  94         default:
  95                 kfree_skb(skb);
  96                 priv->netdev->stats.rx_errors++;
  97                 return -EINVAL;
  98         }
  99
 100         /* If we change the header in loop mode, the checksum is corrupted. */
 101         if (priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP)
 102                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 103         else
 104                 skb->ip_summed = CHECKSUM_NONE;
 105
 106         if (in_interrupt())
 107                 netif_rx(skb);
 108         else
 109                 netif_rx_ni(skb);
 110
 111         /* Update statistics. */
 112         priv->netdev->stats.rx_packets++;
 113         priv->netdev->stats.rx_bytes += pktlen;
 114
 115         return 0;
 116 }
 117
 118 static int delete_device(struct chnl_net *dev)
 119 {
 120         ASSERT_RTNL();
 121         if (dev->netdev)
 122                 unregister_netdevice(dev->netdev);
 123         return 0;
 124 }
 125
 126 static void close_work(struct work_struct *work)
 127 {
 128         struct chnl_net *dev = NULL;
 129         struct list_head *list_node;
 130         struct list_head *_tmp;
 131
 132         rtnl_lock();
 133         list_for_each_safe(list_node, _tmp, &chnl_net_list) {
 134                 dev = list_entry(list_node, struct chnl_net, list_field);
 135                 if (dev->state == CAIF_SHUTDOWN)
 136                         dev_close(dev->netdev);
 137         }
 138         rtnl_unlock();
 139 }
 140 static DECLARE_WORK(close_worker, close_work);
 141
 142 static void chnl_hold(struct cflayer *lyr)
 143 {
 144         struct chnl_net *priv = container_of(lyr, struct chnl_net, chnl);
 145         dev_hold(priv->netdev);
 146 }
 147
 148 static void chnl_put(struct cflayer *lyr)
 149 {
 150         struct chnl_net *priv = container_of(lyr, struct chnl_net, chnl);
 151         dev_put(priv->netdev);
 152 }
 153
 154 static void chnl_flowctrl_cb(struct cflayer *layr, enum caif_ctrlcmd flow,
 155                              int phyid)
 156 {
 157         struct chnl_net *priv = container_of(layr, struct chnl_net, chnl);
 158         pr_debug("NET flowctrl func called flow: %s\n",
 159                 flow == CAIF_CTRLCMD_FLOW_ON_IND ? "ON" :
 160                 flow == CAIF_CTRLCMD_INIT_RSP ? "INIT" :
 161                 flow == CAIF_CTRLCMD_FLOW_OFF_IND ? "OFF" :
 162                 flow == CAIF_CTRLCMD_DEINIT_RSP ? "CLOSE/DEINIT" :
 163                 flow == CAIF_CTRLCMD_INIT_FAIL_RSP ? "OPEN_FAIL" :
 164                 flow == CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND ?
 165                  "REMOTE_SHUTDOWN" : "UKNOWN CTRL COMMAND");
 166
 167
 168
 169         switch (flow) {
 170         case CAIF_CTRLCMD_FLOW_OFF_IND:
 171                 priv->flowenabled = false;
 172                 netif_stop_queue(priv->netdev);
 173                 break;
 174         case CAIF_CTRLCMD_DEINIT_RSP:
 175                 priv->state = CAIF_DISCONNECTED;
 176                 break;
 177         case CAIF_CTRLCMD_INIT_FAIL_RSP:
 178                 priv->state = CAIF_DISCONNECTED;
 179                 wake_up_interruptible(&priv->netmgmt_wq);
 180                 break;
 181         case CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND:
 182                 priv->state = CAIF_SHUTDOWN;
 183                 netif_tx_disable(priv->netdev);
 184                 schedule_work(&close_worker);
 185                 break;
 186         case CAIF_CTRLCMD_FLOW_ON_IND:
 187                 priv->flowenabled = true;
 188                 netif_wake_queue(priv->netdev);
 189                 break;
 190         case CAIF_CTRLCMD_INIT_RSP:
 191                 caif_client_register_refcnt(&priv->chnl, chnl_hold, chnl_put);
 192                 priv->state = CAIF_CONNECTED;
 193                 priv->flowenabled = true;
 194                 netif_wake_queue(priv->netdev);
 195                 wake_up_interruptible(&priv->netmgmt_wq);
 196                 break;
 197         default:
 198                 break;
 199         }
 200 }
 201
 202 static int chnl_net_start_xmit(struct sk_buff *skb, struct net_device *dev)
 203 {
 204         struct chnl_net *priv;
 205         struct cfpkt *pkt = NULL;
 206         int len;
 207         int result = -1;
 208         /* Get our private data. */
 209         priv = netdev_priv(dev);
 210
 211         if (skb->len > priv->netdev->mtu) {
 212                 pr_warn("Size of skb exceeded MTU\n");
 213                 kfree_skb(skb);
 214                 dev->stats.tx_errors++;
 215                 return NETDEV_TX_OK;
 216         }
 217
 218         if (!priv->flowenabled) {
 219                 pr_debug("dropping packets flow off\n");
 220                 kfree_skb(skb);
 221                 dev->stats.tx_dropped++;
 222                 return NETDEV_TX_OK;
 223         }
 224
 225         if (priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP)
 226                 swap(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr);
 227
 228         /* Store original SKB length. */
 229         len = skb->len;
 230
 231         pkt = cfpkt_fromnative(CAIF_DIR_OUT, (void *) skb);
 232
 233         /* Send the packet down the stack. */
 234         result = priv->chnl.dn->transmit(priv->chnl.dn, pkt);
 235         if (result) {
 236                 dev->stats.tx_dropped++;
 237                 return NETDEV_TX_OK;
 238         }
 239
 240         /* Update statistics. */
 241         dev->stats.tx_packets++;
 242         dev->stats.tx_bytes += len;
 243
 244         return NETDEV_TX_OK;
 245 }
 246
 247 static int chnl_net_open(struct net_device *dev)
 248 {
 249         struct chnl_net *priv = NULL;
 250         int result = -1;
 251         int llifindex, headroom, tailroom, mtu;
 252         struct net_device *lldev;
 253         ASSERT_RTNL();
 254         priv = netdev_priv(dev);
 255         if (!priv) {
 256                 pr_debug("chnl_net_open: no priv\n");
 257                 return -ENODEV;
 258         }
 259
 260         if (priv->state != CAIF_CONNECTING) {
 261                 priv->state = CAIF_CONNECTING;
 262                 result = caif_connect_client(dev_net(dev), &priv->conn_req,
 263                                                 &priv->chnl, &llifindex,
 264                                                 &headroom, &tailroom);
 265                 if (result != 0) {
 266                                 pr_debug("err: "
 267                                          "Unable to register and open device,"
 268                                          " Err:%d\n",
 269                                          result);
 270                                 goto error;
 271                 }
 272
 273                 lldev = __dev_get_by_index(dev_net(dev), llifindex);
 274
 275                 if (lldev == NULL) {
 276                         pr_debug("no interface?\n");
 277                         result = -ENODEV;
 278                         goto error;
 279                 }
 280
 281                 dev->needed_tailroom = tailroom + lldev->needed_tailroom;
 282                 dev->hard_header_len = headroom + lldev->hard_header_len +
 283                         lldev->needed_tailroom;
 284
 285                 /*
 286                  * MTU, head-room etc is not know before we have a
 287                  * CAIF link layer device available. MTU calculation may
 288                  * override initial RTNL configuration.
 289                  * MTU is minimum of current mtu, link layer mtu pluss
 290                  * CAIF head and tail, and PDP GPRS contexts max MTU.
 291                  */
 292                 mtu = min_t(int, dev->mtu, lldev->mtu - (headroom + tailroom));
 293                 mtu = min_t(int, GPRS_PDP_MTU, mtu);
 294                 dev_set_mtu(dev, mtu);
 295
 296                 if (mtu < 100) {
 297                         pr_warn("CAIF Interface MTU too small (%d)\n", mtu);
 298                         result = -ENODEV;
 299                         goto error;
 300                 }
 301         }
 302
 303         rtnl_unlock();  /* Release RTNL lock during connect wait */
 304
 305         result = wait_event_interruptible_timeout(priv->netmgmt_wq,
 306                                                 priv->state != CAIF_CONNECTING,
 307                                                 CONNECT_TIMEOUT);
 308
 309         rtnl_lock();
 310
 311         if (result == -ERESTARTSYS) {
 312                 pr_debug("wait_event_interruptible woken by a signal\n");
 313                 result = -ERESTARTSYS;
 314                 goto error;
 315         }
 316
 317         if (result == 0) {
 318                 pr_debug("connect timeout\n");
 319                 caif_disconnect_client(dev_net(dev), &priv->chnl);
 320                 priv->state = CAIF_DISCONNECTED;
 321                 pr_debug("state disconnected\n");
 322                 result = -ETIMEDOUT;
 323                 goto error;
 324         }
 325
 326         if (priv->state != CAIF_CONNECTED) {
 327                 pr_debug("connect failed\n");
 328                 result = -ECONNREFUSED;
 329                 goto error;
 330         }
 331         pr_debug("CAIF Netdevice connected\n");
 332         return 0;
 333
 334 error:
 335         caif_disconnect_client(dev_net(dev), &priv->chnl);
 336         priv->state = CAIF_DISCONNECTED;
 337         pr_debug("state disconnected\n");
 338         return result;
 339
 340 }
 341
 342 static int chnl_net_stop(struct net_device *dev)
 343 {
 344         struct chnl_net *priv;
 345
 346         ASSERT_RTNL();
 347         priv = netdev_priv(dev);
 348         priv->state = CAIF_DISCONNECTED;
 349         caif_disconnect_client(dev_net(dev), &priv->chnl);
 350         return 0;
 351 }
 352
 353 static int chnl_net_init(struct net_device *dev)
 354 {
 355         struct chnl_net *priv;
 356         ASSERT_RTNL();
 357         priv = netdev_priv(dev);
 358         strncpy(priv->name, dev->name, sizeof(priv->name));
 359         INIT_LIST_HEAD(&priv->list_field);
 360         return 0;
 361 }
 362
 363 static void chnl_net_uninit(struct net_device *dev)
 364 {
 365         struct chnl_net *priv;
 366         ASSERT_RTNL();
 367         priv = netdev_priv(dev);
 368         list_del_init(&priv->list_field);
 369 }
 370
 371 static const struct net_device_ops netdev_ops = {
 372         .ndo_open = chnl_net_open,
 373         .ndo_stop = chnl_net_stop,
 374         .ndo_init = chnl_net_init,
 375         .ndo_uninit = chnl_net_uninit,
 376         .ndo_start_xmit = chnl_net_start_xmit,
 377 };
 378
 379 static void chnl_net_destructor(struct net_device *dev)
 380 {
 381         struct chnl_net *priv = netdev_priv(dev);
 382         caif_free_client(&priv->chnl);
 383         free_netdev(dev);
 384 }
 385
 386 static void ipcaif_net_setup(struct net_device *dev)
 387 {
 388         struct chnl_net *priv;
 389         dev->netdev_ops = &netdev_ops;
 390         dev->destructor = chnl_net_destructor;
 391         dev->flags |= IFF_NOARP;
 392         dev->flags |= IFF_POINTOPOINT;
 393         dev->mtu = GPRS_PDP_MTU;
 394         dev->tx_queue_len = CAIF_NET_DEFAULT_QUEUE_LEN;
 395
 396         priv = netdev_priv(dev);
 397         priv->chnl.receive = chnl_recv_cb;
 398         priv->chnl.ctrlcmd = chnl_flowctrl_cb;
 399         priv->netdev = dev;
 400         priv->conn_req.protocol = CAIFPROTO_DATAGRAM;
 401         priv->conn_req.link_selector = CAIF_LINK_HIGH_BANDW;
 402         priv->conn_req.priority = CAIF_PRIO_LOW;
 403         /* Insert illegal value */
 404         priv->conn_req.sockaddr.u.dgm.connection_id = UNDEF_CONNID;
 405         priv->flowenabled = false;
 406
 407         init_waitqueue_head(&priv->netmgmt_wq);
 408 }
 409
 410
 411 static int ipcaif_fill_info(struct sk_buff *skb, const struct net_device *dev)
 412 {
 413         struct chnl_net *priv;
 414         u8 loop;
 415         priv = netdev_priv(dev);
 416         if (nla_put_u32(skb, IFLA_CAIF_IPV4_CONNID,
 417                         priv->conn_req.sockaddr.u.dgm.connection_id) ||
 418             nla_put_u32(skb, IFLA_CAIF_IPV6_CONNID,
 419                         priv->conn_req.sockaddr.u.dgm.connection_id))
 420                 goto nla_put_failure;
 421         loop = priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP;
 422         if (nla_put_u8(skb, IFLA_CAIF_LOOPBACK, loop))
 423                 goto nla_put_failure;
 424         return 0;
 425 nla_put_failure:
 426         return -EMSGSIZE;
 427
 428 }
 429
 430 static void caif_netlink_parms(struct nlattr *data[],
 431                                struct caif_connect_request *conn_req)
 432 {
 433         if (!data) {
 434                 pr_warn("no params data found\n");
 435                 return;
 436         }
 437         if (data[IFLA_CAIF_IPV4_CONNID])
 438                 conn_req->sockaddr.u.dgm.connection_id =
 439                         nla_get_u32(data[IFLA_CAIF_IPV4_CONNID]);
 440         if (data[IFLA_CAIF_IPV6_CONNID])
 441                 conn_req->sockaddr.u.dgm.connection_id =
 442                         nla_get_u32(data[IFLA_CAIF_IPV6_CONNID]);
 443         if (data[IFLA_CAIF_LOOPBACK]) {
 444                 if (nla_get_u8(data[IFLA_CAIF_LOOPBACK]))
 445                         conn_req->protocol = CAIFPROTO_DATAGRAM_LOOP;
 446                 else
 447                         conn_req->protocol = CAIFPROTO_DATAGRAM;
 448         }
 449 }
 450
 451 static int ipcaif_newlink(struct net *src_net, struct net_device *dev,
 452                           struct nlattr *tb[], struct nlattr *data[])
 453 {
 454         int ret;
 455         struct chnl_net *caifdev;
 456         ASSERT_RTNL();
 457         caifdev = netdev_priv(dev);
 458         caif_netlink_parms(data, &caifdev->conn_req);
 459
 460         ret = register_netdevice(dev);
 461         if (ret)
 462                 pr_warn("device rtml registration failed\n");
 463         else
 464                 list_add(&caifdev->list_field, &chnl_net_list);
 465
 466         /* Use ifindex as connection id, and use loopback channel default. */
 467         if (caifdev->conn_req.sockaddr.u.dgm.connection_id == UNDEF_CONNID) {
 468                 caifdev->conn_req.sockaddr.u.dgm.connection_id = dev->ifindex;
 469                 caifdev->conn_req.protocol = CAIFPROTO_DATAGRAM_LOOP;
 470         }
 471         return ret;
 472 }
 473
 474 static int ipcaif_changelink(struct net_device *dev, struct nlattr *tb[],
 475                              struct nlattr *data[])
 476 {
 477         struct chnl_net *caifdev;
 478         ASSERT_RTNL();
 479         caifdev = netdev_priv(dev);
 480         caif_netlink_parms(data, &caifdev->conn_req);
 481         netdev_state_change(dev);
 482         return 0;
 483 }
 484
 485 static size_t ipcaif_get_size(const struct net_device *dev)
 486 {
 487         return
 488                 /* IFLA_CAIF_IPV4_CONNID */
 489                 nla_total_size(4) +
 490                 /* IFLA_CAIF_IPV6_CONNID */
 491                 nla_total_size(4) +
 492                 /* IFLA_CAIF_LOOPBACK */
 493                 nla_total_size(2) +
 494                 0;
 495 }
 496
 497 static const struct nla_policy ipcaif_policy[IFLA_CAIF_MAX + 1] = {
 498         [IFLA_CAIF_IPV4_CONNID]       = { .type = NLA_U32 },
 499         [IFLA_CAIF_IPV6_CONNID]       = { .type = NLA_U32 },
 500         [IFLA_CAIF_LOOPBACK]          = { .type = NLA_U8 }
 501 };
 502
 503
 504 static struct rtnl_link_ops ipcaif_link_ops __read_mostly = {
 505         .kind           = "caif",
 506         .priv_size      = sizeof(struct chnl_net),
 507         .setup          = ipcaif_net_setup,
 508         .maxtype        = IFLA_CAIF_MAX,
 509         .policy         = ipcaif_policy,
 510         .newlink        = ipcaif_newlink,
 511         .changelink     = ipcaif_changelink,
 512         .get_size       = ipcaif_get_size,
 513         .fill_info      = ipcaif_fill_info,
 514
 515 };
 516
 517 static int __init chnl_init_module(void)
 518 {
 519         return rtnl_link_register(&ipcaif_link_ops);
 520 }
 521
 522 static void __exit chnl_exit_module(void)
 523 {
 524         struct chnl_net *dev = NULL;
 525         struct list_head *list_node;
 526         struct list_head *_tmp;
 527         rtnl_link_unregister(&ipcaif_link_ops);
 528         rtnl_lock();
 529         list_for_each_safe(list_node, _tmp, &chnl_net_list) {
 530                 dev = list_entry(list_node, struct chnl_net, list_field);
 531                 list_del_init(list_node);
 532                 delete_device(dev);
 533         }
 534         rtnl_unlock();
 535 }
 536
 537 module_init(chnl_init_module);
 538 module_exit(chnl_exit_module);