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 void robust_list_del(struct list_head *delete_node)
  59 {
  60         struct list_head *list_node;
  61         struct list_head *n;
  62         ASSERT_RTNL();
  63         list_for_each_safe(list_node, n, &chnl_net_list) {
  64                 if (list_node == delete_node) {
  65                         list_del(list_node);
  66                         return;
  67                 }
  68         }
  69         WARN_ON(1);
  70 }
  71
  72 static int chnl_recv_cb(struct cflayer *layr, struct cfpkt *pkt)
  73 {
  74         struct sk_buff *skb;
  75         struct chnl_net *priv;
  76         int pktlen;
  77         const u8 *ip_version;
  78         u8 buf;
  79
  80         priv = container_of(layr, struct chnl_net, chnl);
  81         if (!priv)
  82                 return -EINVAL;
  83
  84         skb = (struct sk_buff *) cfpkt_tonative(pkt);
  85
  86         /* Get length of CAIF packet. */
  87         pktlen = skb->len;
  88
  89         /* Pass some minimum information and
  90          * send the packet to the net stack.
  91          */
  92         skb->dev = priv->netdev;
  93
  94         /* check the version of IP */
  95         ip_version = skb_header_pointer(skb, 0, 1, &buf);
  96         if (!ip_version) {
  97                 kfree_skb(skb);
  98                 return -EINVAL;
  99         }
 100
 101         switch (*ip_version >> 4) {
 102         case 4:
 103                 skb->protocol = htons(ETH_P_IP);
 104                 break;
 105         case 6:
 106                 skb->protocol = htons(ETH_P_IPV6);
 107                 break;
 108         default:
 109                 kfree_skb(skb);
 110                 priv->netdev->stats.rx_errors++;
 111                 return -EINVAL;
 112         }
 113
 114         /* If we change the header in loop mode, the checksum is corrupted. */
 115         if (priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP)
 116                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 117         else
 118                 skb->ip_summed = CHECKSUM_NONE;
 119
 120         if (in_interrupt())
 121                 netif_rx(skb);
 122         else
 123                 netif_rx_ni(skb);
 124
 125         /* Update statistics. */
 126         priv->netdev->stats.rx_packets++;
 127         priv->netdev->stats.rx_bytes += pktlen;
 128
 129         return 0;
 130 }
 131
 132 static int delete_device(struct chnl_net *dev)
 133 {
 134         ASSERT_RTNL();
 135         if (dev->netdev)
 136                 unregister_netdevice(dev->netdev);
 137         return 0;
 138 }
 139
 140 static void close_work(struct work_struct *work)
 141 {
 142         struct chnl_net *dev = NULL;
 143         struct list_head *list_node;
 144         struct list_head *_tmp;
 145
 146         rtnl_lock();
 147         list_for_each_safe(list_node, _tmp, &chnl_net_list) {
 148                 dev = list_entry(list_node, struct chnl_net, list_field);
 149                 if (dev->state == CAIF_SHUTDOWN)
 150                         dev_close(dev->netdev);
 151         }
 152         rtnl_unlock();
 153 }
 154 static DECLARE_WORK(close_worker, close_work);
 155
 156 static void chnl_hold(struct cflayer *lyr)
 157 {
 158         struct chnl_net *priv = container_of(lyr, struct chnl_net, chnl);
 159         dev_hold(priv->netdev);
 160 }
 161
 162 static void chnl_put(struct cflayer *lyr)
 163 {
 164         struct chnl_net *priv = container_of(lyr, struct chnl_net, chnl);
 165         dev_put(priv->netdev);
 166 }
 167
 168 static void chnl_flowctrl_cb(struct cflayer *layr, enum caif_ctrlcmd flow,
 169                              int phyid)
 170 {
 171         struct chnl_net *priv = container_of(layr, struct chnl_net, chnl);
 172         pr_debug("NET flowctrl func called flow: %s\n",
 173                 flow == CAIF_CTRLCMD_FLOW_ON_IND ? "ON" :
 174                 flow == CAIF_CTRLCMD_INIT_RSP ? "INIT" :
 175                 flow == CAIF_CTRLCMD_FLOW_OFF_IND ? "OFF" :
 176                 flow == CAIF_CTRLCMD_DEINIT_RSP ? "CLOSE/DEINIT" :
 177                 flow == CAIF_CTRLCMD_INIT_FAIL_RSP ? "OPEN_FAIL" :
 178                 flow == CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND ?
 179                  "REMOTE_SHUTDOWN" : "UKNOWN CTRL COMMAND");
 180
 181
 182
 183         switch (flow) {
 184         case CAIF_CTRLCMD_FLOW_OFF_IND:
 185                 priv->flowenabled = false;
 186                 netif_stop_queue(priv->netdev);
 187                 break;
 188         case CAIF_CTRLCMD_DEINIT_RSP:
 189                 priv->state = CAIF_DISCONNECTED;
 190                 break;
 191         case CAIF_CTRLCMD_INIT_FAIL_RSP:
 192                 priv->state = CAIF_DISCONNECTED;
 193                 wake_up_interruptible(&priv->netmgmt_wq);
 194                 break;
 195         case CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND:
 196                 priv->state = CAIF_SHUTDOWN;
 197                 netif_tx_disable(priv->netdev);
 198                 schedule_work(&close_worker);
 199                 break;
 200         case CAIF_CTRLCMD_FLOW_ON_IND:
 201                 priv->flowenabled = true;
 202                 netif_wake_queue(priv->netdev);
 203                 break;
 204         case CAIF_CTRLCMD_INIT_RSP:
 205                 caif_client_register_refcnt(&priv->chnl, chnl_hold, chnl_put);
 206                 priv->state = CAIF_CONNECTED;
 207                 priv->flowenabled = true;
 208                 netif_wake_queue(priv->netdev);
 209                 wake_up_interruptible(&priv->netmgmt_wq);
 210                 break;
 211         default:
 212                 break;
 213         }
 214 }
 215
 216 static int chnl_net_start_xmit(struct sk_buff *skb, struct net_device *dev)
 217 {
 218         struct chnl_net *priv;
 219         struct cfpkt *pkt = NULL;
 220         int len;
 221         int result = -1;
 222         /* Get our private data. */
 223         priv = netdev_priv(dev);
 224
 225         if (skb->len > priv->netdev->mtu) {
 226                 pr_warn("Size of skb exceeded MTU\n");
 227                 kfree_skb(skb);
 228                 dev->stats.tx_errors++;
 229                 return NETDEV_TX_OK;
 230         }
 231
 232         if (!priv->flowenabled) {
 233                 pr_debug("dropping packets flow off\n");
 234                 kfree_skb(skb);
 235                 dev->stats.tx_dropped++;
 236                 return NETDEV_TX_OK;
 237         }
 238
 239         if (priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP)
 240                 swap(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr);
 241
 242         /* Store original SKB length. */
 243         len = skb->len;
 244
 245         pkt = cfpkt_fromnative(CAIF_DIR_OUT, (void *) skb);
 246
 247         /* Send the packet down the stack. */
 248         result = priv->chnl.dn->transmit(priv->chnl.dn, pkt);
 249         if (result) {
 250                 dev->stats.tx_dropped++;
 251                 return NETDEV_TX_OK;
 252         }
 253
 254         /* Update statistics. */
 255         dev->stats.tx_packets++;
 256         dev->stats.tx_bytes += len;
 257
 258         return NETDEV_TX_OK;
 259 }
 260
 261 static int chnl_net_open(struct net_device *dev)
 262 {
 263         struct chnl_net *priv = NULL;
 264         int result = -1;
 265         int llifindex, headroom, tailroom, mtu;
 266         struct net_device *lldev;
 267         ASSERT_RTNL();
 268         priv = netdev_priv(dev);
 269         if (!priv) {
 270                 pr_debug("chnl_net_open: no priv\n");
 271                 return -ENODEV;
 272         }
 273
 274         if (priv->state != CAIF_CONNECTING) {
 275                 priv->state = CAIF_CONNECTING;
 276                 result = caif_connect_client(dev_net(dev), &priv->conn_req,
 277                                                 &priv->chnl, &llifindex,
 278                                                 &headroom, &tailroom);
 279                 if (result != 0) {
 280                                 pr_debug("err: "
 281                                          "Unable to register and open device,"
 282                                          " Err:%d\n",
 283                                          result);
 284                                 goto error;
 285                 }
 286
 287                 lldev = __dev_get_by_index(dev_net(dev), llifindex);
 288
 289                 if (lldev == NULL) {
 290                         pr_debug("no interface?\n");
 291                         result = -ENODEV;
 292                         goto error;
 293                 }
 294
 295                 dev->needed_tailroom = tailroom + lldev->needed_tailroom;
 296                 dev->hard_header_len = headroom + lldev->hard_header_len +
 297                         lldev->needed_tailroom;
 298
 299                 /*
 300                  * MTU, head-room etc is not know before we have a
 301                  * CAIF link layer device available. MTU calculation may
 302                  * override initial RTNL configuration.
 303                  * MTU is minimum of current mtu, link layer mtu pluss
 304                  * CAIF head and tail, and PDP GPRS contexts max MTU.
 305                  */
 306                 mtu = min_t(int, dev->mtu, lldev->mtu - (headroom + tailroom));
 307                 mtu = min_t(int, GPRS_PDP_MTU, mtu);
 308                 dev_set_mtu(dev, mtu);
 309
 310                 if (mtu < 100) {
 311                         pr_warn("CAIF Interface MTU too small (%d)\n", mtu);
 312                         result = -ENODEV;
 313                         goto error;
 314                 }
 315         }
 316
 317         rtnl_unlock();  /* Release RTNL lock during connect wait */
 318
 319         result = wait_event_interruptible_timeout(priv->netmgmt_wq,
 320                                                 priv->state != CAIF_CONNECTING,
 321                                                 CONNECT_TIMEOUT);
 322
 323         rtnl_lock();
 324
 325         if (result == -ERESTARTSYS) {
 326                 pr_debug("wait_event_interruptible woken by a signal\n");
 327                 result = -ERESTARTSYS;
 328                 goto error;
 329         }
 330
 331         if (result == 0) {
 332                 pr_debug("connect timeout\n");
 333                 caif_disconnect_client(dev_net(dev), &priv->chnl);
 334                 priv->state = CAIF_DISCONNECTED;
 335                 pr_debug("state disconnected\n");
 336                 result = -ETIMEDOUT;
 337                 goto error;
 338         }
 339
 340         if (priv->state != CAIF_CONNECTED) {
 341                 pr_debug("connect failed\n");
 342                 result = -ECONNREFUSED;
 343                 goto error;
 344         }
 345         pr_debug("CAIF Netdevice connected\n");
 346         return 0;
 347
 348 error:
 349         caif_disconnect_client(dev_net(dev), &priv->chnl);
 350         priv->state = CAIF_DISCONNECTED;
 351         pr_debug("state disconnected\n");
 352         return result;
 353
 354 }
 355
 356 static int chnl_net_stop(struct net_device *dev)
 357 {
 358         struct chnl_net *priv;
 359
 360         ASSERT_RTNL();
 361         priv = netdev_priv(dev);
 362         priv->state = CAIF_DISCONNECTED;
 363         caif_disconnect_client(dev_net(dev), &priv->chnl);
 364         return 0;
 365 }
 366
 367 static int chnl_net_init(struct net_device *dev)
 368 {
 369         struct chnl_net *priv;
 370         ASSERT_RTNL();
 371         priv = netdev_priv(dev);
 372         strncpy(priv->name, dev->name, sizeof(priv->name));
 373         return 0;
 374 }
 375
 376 static void chnl_net_uninit(struct net_device *dev)
 377 {
 378         struct chnl_net *priv;
 379         ASSERT_RTNL();
 380         priv = netdev_priv(dev);
 381         robust_list_del(&priv->list_field);
 382 }
 383
 384 static const struct net_device_ops netdev_ops = {
 385         .ndo_open = chnl_net_open,
 386         .ndo_stop = chnl_net_stop,
 387         .ndo_init = chnl_net_init,
 388         .ndo_uninit = chnl_net_uninit,
 389         .ndo_start_xmit = chnl_net_start_xmit,
 390 };
 391
 392 static void chnl_net_destructor(struct net_device *dev)
 393 {
 394         struct chnl_net *priv = netdev_priv(dev);
 395         caif_free_client(&priv->chnl);
 396         free_netdev(dev);
 397 }
 398
 399 static void ipcaif_net_setup(struct net_device *dev)
 400 {
 401         struct chnl_net *priv;
 402         dev->netdev_ops = &netdev_ops;
 403         dev->destructor = chnl_net_destructor;
 404         dev->flags |= IFF_NOARP;
 405         dev->flags |= IFF_POINTOPOINT;
 406         dev->mtu = GPRS_PDP_MTU;
 407         dev->tx_queue_len = CAIF_NET_DEFAULT_QUEUE_LEN;
 408
 409         priv = netdev_priv(dev);
 410         priv->chnl.receive = chnl_recv_cb;
 411         priv->chnl.ctrlcmd = chnl_flowctrl_cb;
 412         priv->netdev = dev;
 413         priv->conn_req.protocol = CAIFPROTO_DATAGRAM;
 414         priv->conn_req.link_selector = CAIF_LINK_HIGH_BANDW;
 415         priv->conn_req.priority = CAIF_PRIO_LOW;
 416         /* Insert illegal value */
 417         priv->conn_req.sockaddr.u.dgm.connection_id = UNDEF_CONNID;
 418         priv->flowenabled = false;
 419
 420         init_waitqueue_head(&priv->netmgmt_wq);
 421 }
 422
 423
 424 static int ipcaif_fill_info(struct sk_buff *skb, const struct net_device *dev)
 425 {
 426         struct chnl_net *priv;
 427         u8 loop;
 428         priv = netdev_priv(dev);
 429         if (nla_put_u32(skb, IFLA_CAIF_IPV4_CONNID,
 430                         priv->conn_req.sockaddr.u.dgm.connection_id) ||
 431             nla_put_u32(skb, IFLA_CAIF_IPV6_CONNID,
 432                         priv->conn_req.sockaddr.u.dgm.connection_id))
 433                 goto nla_put_failure;
 434         loop = priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP;
 435         if (nla_put_u8(skb, IFLA_CAIF_LOOPBACK, loop))
 436                 goto nla_put_failure;
 437         return 0;
 438 nla_put_failure:
 439         return -EMSGSIZE;
 440
 441 }
 442
 443 static void caif_netlink_parms(struct nlattr *data[],
 444                                struct caif_connect_request *conn_req)
 445 {
 446         if (!data) {
 447                 pr_warn("no params data found\n");
 448                 return;
 449         }
 450         if (data[IFLA_CAIF_IPV4_CONNID])
 451                 conn_req->sockaddr.u.dgm.connection_id =
 452                         nla_get_u32(data[IFLA_CAIF_IPV4_CONNID]);
 453         if (data[IFLA_CAIF_IPV6_CONNID])
 454                 conn_req->sockaddr.u.dgm.connection_id =
 455                         nla_get_u32(data[IFLA_CAIF_IPV6_CONNID]);
 456         if (data[IFLA_CAIF_LOOPBACK]) {
 457                 if (nla_get_u8(data[IFLA_CAIF_LOOPBACK]))
 458                         conn_req->protocol = CAIFPROTO_DATAGRAM_LOOP;
 459                 else
 460                         conn_req->protocol = CAIFPROTO_DATAGRAM;
 461         }
 462 }
 463
 464 static int ipcaif_newlink(struct net *src_net, struct net_device *dev,
 465                           struct nlattr *tb[], struct nlattr *data[])
 466 {
 467         int ret;
 468         struct chnl_net *caifdev;
 469         ASSERT_RTNL();
 470         caifdev = netdev_priv(dev);
 471         caif_netlink_parms(data, &caifdev->conn_req);
 472
 473         ret = register_netdevice(dev);
 474         if (ret)
 475                 pr_warn("device rtml registration failed\n");
 476         else
 477                 list_add(&caifdev->list_field, &chnl_net_list);
 478
 479         /* Use ifindex as connection id, and use loopback channel default. */
 480         if (caifdev->conn_req.sockaddr.u.dgm.connection_id == UNDEF_CONNID) {
 481                 caifdev->conn_req.sockaddr.u.dgm.connection_id = dev->ifindex;
 482                 caifdev->conn_req.protocol = CAIFPROTO_DATAGRAM_LOOP;
 483         }
 484         return ret;
 485 }
 486
 487 static int ipcaif_changelink(struct net_device *dev, struct nlattr *tb[],
 488                              struct nlattr *data[])
 489 {
 490         struct chnl_net *caifdev;
 491         ASSERT_RTNL();
 492         caifdev = netdev_priv(dev);
 493         caif_netlink_parms(data, &caifdev->conn_req);
 494         netdev_state_change(dev);
 495         return 0;
 496 }
 497
 498 static size_t ipcaif_get_size(const struct net_device *dev)
 499 {
 500         return
 501                 /* IFLA_CAIF_IPV4_CONNID */
 502                 nla_total_size(4) +
 503                 /* IFLA_CAIF_IPV6_CONNID */
 504                 nla_total_size(4) +
 505                 /* IFLA_CAIF_LOOPBACK */
 506                 nla_total_size(2) +
 507                 0;
 508 }
 509
 510 static const struct nla_policy ipcaif_policy[IFLA_CAIF_MAX + 1] = {
 511         [IFLA_CAIF_IPV4_CONNID]       = { .type = NLA_U32 },
 512         [IFLA_CAIF_IPV6_CONNID]       = { .type = NLA_U32 },
 513         [IFLA_CAIF_LOOPBACK]          = { .type = NLA_U8 }
 514 };
 515
 516
 517 static struct rtnl_link_ops ipcaif_link_ops __read_mostly = {
 518         .kind           = "caif",
 519         .priv_size      = sizeof(struct chnl_net),
 520         .setup          = ipcaif_net_setup,
 521         .maxtype        = IFLA_CAIF_MAX,
 522         .policy         = ipcaif_policy,
 523         .newlink        = ipcaif_newlink,
 524         .changelink     = ipcaif_changelink,
 525         .get_size       = ipcaif_get_size,
 526         .fill_info      = ipcaif_fill_info,
 527
 528 };
 529
 530 static int __init chnl_init_module(void)
 531 {
 532         return rtnl_link_register(&ipcaif_link_ops);
 533 }
 534
 535 static void __exit chnl_exit_module(void)
 536 {
 537         struct chnl_net *dev = NULL;
 538         struct list_head *list_node;
 539         struct list_head *_tmp;
 540         rtnl_link_unregister(&ipcaif_link_ops);
 541         rtnl_lock();
 542         list_for_each_safe(list_node, _tmp, &chnl_net_list) {
 543                 dev = list_entry(list_node, struct chnl_net, list_field);
 544                 list_del(list_node);
 545                 delete_device(dev);
 546         }
 547         rtnl_unlock();
 548 }
 549
 550 module_init(chnl_init_module);
 551 module_exit(chnl_exit_module);