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 caif_connect_request conn_req;
  48         struct list_head list_field;
  49         struct net_device *netdev;
  50         char name[256];
  51         wait_queue_head_t netmgmt_wq;
  52         /* Flow status to remember and control the transmission. */
  53         bool flowenabled;
  54         enum caif_states state;
  55 };
  56
  57 static void robust_list_del(struct list_head *delete_node)
  58 {
  59         struct list_head *list_node;
  60         struct list_head *n;
  61         ASSERT_RTNL();
  62         list_for_each_safe(list_node, n, &chnl_net_list) {
  63                 if (list_node == delete_node) {
  64                         list_del(list_node);
  65                         return;
  66                 }
  67         }
  68         WARN_ON(1);
  69 }
  70
  71 static int chnl_recv_cb(struct cflayer *layr, struct cfpkt *pkt)
  72 {
  73         struct sk_buff *skb;
  74         struct chnl_net *priv;
  75         int pktlen;
  76         const u8 *ip_version;
  77         u8 buf;
  78
  79         priv = container_of(layr, struct chnl_net, chnl);
  80         if (!priv)
  81                 return -EINVAL;
  82
  83         skb = (struct sk_buff *) cfpkt_tonative(pkt);
  84
  85         /* Get length of CAIF packet. */
  86         pktlen = skb->len;
  87
  88         /* Pass some minimum information and
  89          * send the packet to the net stack.
  90          */
  91         skb->dev = priv->netdev;
  92
  93         /* check the version of IP */
  94         ip_version = skb_header_pointer(skb, 0, 1, &buf);
  95         if (!ip_version) {
  96                 kfree_skb(skb);
  97                 return -EINVAL;
  98         }
  99
 100         switch (*ip_version >> 4) {
 101         case 4:
 102                 skb->protocol = htons(ETH_P_IP);
 103                 break;
 104         case 6:
 105                 skb->protocol = htons(ETH_P_IPV6);
 106                 break;
 107         default:
 108                 kfree_skb(skb);
 109                 priv->netdev->stats.rx_errors++;
 110                 return -EINVAL;
 111         }
 112
 113         /* If we change the header in loop mode, the checksum is corrupted. */
 114         if (priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP)
 115                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 116         else
 117                 skb->ip_summed = CHECKSUM_NONE;
 118
 119         if (in_interrupt())
 120                 netif_rx(skb);
 121         else
 122                 netif_rx_ni(skb);
 123
 124         /* Update statistics. */
 125         priv->netdev->stats.rx_packets++;
 126         priv->netdev->stats.rx_bytes += pktlen;
 127
 128         return 0;
 129 }
 130
 131 static int delete_device(struct chnl_net *dev)
 132 {
 133         ASSERT_RTNL();
 134         if (dev->netdev)
 135                 unregister_netdevice(dev->netdev);
 136         return 0;
 137 }
 138
 139 static void close_work(struct work_struct *work)
 140 {
 141         struct chnl_net *dev = NULL;
 142         struct list_head *list_node;
 143         struct list_head *_tmp;
 144
 145         rtnl_lock();
 146         list_for_each_safe(list_node, _tmp, &chnl_net_list) {
 147                 dev = list_entry(list_node, struct chnl_net, list_field);
 148                 if (dev->state == CAIF_SHUTDOWN)
 149                         dev_close(dev->netdev);
 150         }
 151         rtnl_unlock();
 152 }
 153 static DECLARE_WORK(close_worker, close_work);
 154
 155 static void chnl_hold(struct cflayer *lyr)
 156 {
 157         struct chnl_net *priv = container_of(lyr, struct chnl_net, chnl);
 158         dev_hold(priv->netdev);
 159 }
 160
 161 static void chnl_put(struct cflayer *lyr)
 162 {
 163         struct chnl_net *priv = container_of(lyr, struct chnl_net, chnl);
 164         dev_put(priv->netdev);
 165 }
 166
 167 static void chnl_flowctrl_cb(struct cflayer *layr, enum caif_ctrlcmd flow,
 168                              int phyid)
 169 {
 170         struct chnl_net *priv = container_of(layr, struct chnl_net, chnl);
 171         pr_debug("NET flowctrl func called flow: %s\n",
 172                 flow == CAIF_CTRLCMD_FLOW_ON_IND ? "ON" :
 173                 flow == CAIF_CTRLCMD_INIT_RSP ? "INIT" :
 174                 flow == CAIF_CTRLCMD_FLOW_OFF_IND ? "OFF" :
 175                 flow == CAIF_CTRLCMD_DEINIT_RSP ? "CLOSE/DEINIT" :
 176                 flow == CAIF_CTRLCMD_INIT_FAIL_RSP ? "OPEN_FAIL" :
 177                 flow == CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND ?
 178                  "REMOTE_SHUTDOWN" : "UKNOWN CTRL COMMAND");
 179
 180
 181
 182         switch (flow) {
 183         case CAIF_CTRLCMD_FLOW_OFF_IND:
 184                 priv->flowenabled = false;
 185                 netif_stop_queue(priv->netdev);
 186                 break;
 187         case CAIF_CTRLCMD_DEINIT_RSP:
 188                 priv->state = CAIF_DISCONNECTED;
 189                 break;
 190         case CAIF_CTRLCMD_INIT_FAIL_RSP:
 191                 priv->state = CAIF_DISCONNECTED;
 192                 wake_up_interruptible(&priv->netmgmt_wq);
 193                 break;
 194         case CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND:
 195                 priv->state = CAIF_SHUTDOWN;
 196                 netif_tx_disable(priv->netdev);
 197                 schedule_work(&close_worker);
 198                 break;
 199         case CAIF_CTRLCMD_FLOW_ON_IND:
 200                 priv->flowenabled = true;
 201                 netif_wake_queue(priv->netdev);
 202                 break;
 203         case CAIF_CTRLCMD_INIT_RSP:
 204                 caif_client_register_refcnt(&priv->chnl, chnl_hold, chnl_put);
 205                 priv->state = CAIF_CONNECTED;
 206                 priv->flowenabled = true;
 207                 netif_wake_queue(priv->netdev);
 208                 wake_up_interruptible(&priv->netmgmt_wq);
 209                 break;
 210         default:
 211                 break;
 212         }
 213 }
 214
 215 static int chnl_net_start_xmit(struct sk_buff *skb, struct net_device *dev)
 216 {
 217         struct chnl_net *priv;
 218         struct cfpkt *pkt = NULL;
 219         int len;
 220         int result = -1;
 221         /* Get our private data. */
 222         priv = netdev_priv(dev);
 223
 224         if (skb->len > priv->netdev->mtu) {
 225                 pr_warn("Size of skb exceeded MTU\n");
 226                 kfree_skb(skb);
 227                 dev->stats.tx_errors++;
 228                 return NETDEV_TX_OK;
 229         }
 230
 231         if (!priv->flowenabled) {
 232                 pr_debug("dropping packets flow off\n");
 233                 kfree_skb(skb);
 234                 dev->stats.tx_dropped++;
 235                 return NETDEV_TX_OK;
 236         }
 237
 238         if (priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP)
 239                 swap(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr);
 240
 241         /* Store original SKB length. */
 242         len = skb->len;
 243
 244         pkt = cfpkt_fromnative(CAIF_DIR_OUT, (void *) skb);
 245
 246         /* Send the packet down the stack. */
 247         result = priv->chnl.dn->transmit(priv->chnl.dn, pkt);
 248         if (result) {
 249                 dev->stats.tx_dropped++;
 250                 return NETDEV_TX_OK;
 251         }
 252
 253         /* Update statistics. */
 254         dev->stats.tx_packets++;
 255         dev->stats.tx_bytes += len;
 256
 257         return NETDEV_TX_OK;
 258 }
 259
 260 static int chnl_net_open(struct net_device *dev)
 261 {
 262         struct chnl_net *priv = NULL;
 263         int result = -1;
 264         int llifindex, headroom, tailroom, mtu;
 265         struct net_device *lldev;
 266         ASSERT_RTNL();
 267         priv = netdev_priv(dev);
 268         if (!priv) {
 269                 pr_debug("chnl_net_open: no priv\n");
 270                 return -ENODEV;
 271         }
 272
 273         if (priv->state != CAIF_CONNECTING) {
 274                 priv->state = CAIF_CONNECTING;
 275                 result = caif_connect_client(dev_net(dev), &priv->conn_req,
 276                                                 &priv->chnl, &llifindex,
 277                                                 &headroom, &tailroom);
 278                 if (result != 0) {
 279                                 pr_debug("err: "
 280                                          "Unable to register and open device,"
 281                                          " Err:%d\n",
 282                                          result);
 283                                 goto error;
 284                 }
 285
 286                 lldev = __dev_get_by_index(dev_net(dev), llifindex);
 287
 288                 if (lldev == NULL) {
 289                         pr_debug("no interface?\n");
 290                         result = -ENODEV;
 291                         goto error;
 292                 }
 293
 294                 dev->needed_tailroom = tailroom + lldev->needed_tailroom;
 295                 dev->hard_header_len = headroom + lldev->hard_header_len +
 296                         lldev->needed_tailroom;
 297
 298                 /*
 299                  * MTU, head-room etc is not know before we have a
 300                  * CAIF link layer device available. MTU calculation may
 301                  * override initial RTNL configuration.
 302                  * MTU is minimum of current mtu, link layer mtu pluss
 303                  * CAIF head and tail, and PDP GPRS contexts max MTU.
 304                  */
 305                 mtu = min_t(int, dev->mtu, lldev->mtu - (headroom + tailroom));
 306                 mtu = min_t(int, GPRS_PDP_MTU, mtu);
 307                 dev_set_mtu(dev, mtu);
 308
 309                 if (mtu < 100) {
 310                         pr_warn("CAIF Interface MTU too small (%d)\n", mtu);
 311                         result = -ENODEV;
 312                         goto error;
 313                 }
 314         }
 315
 316         rtnl_unlock();  /* Release RTNL lock during connect wait */
 317
 318         result = wait_event_interruptible_timeout(priv->netmgmt_wq,
 319                                                 priv->state != CAIF_CONNECTING,
 320                                                 CONNECT_TIMEOUT);
 321
 322         rtnl_lock();
 323
 324         if (result == -ERESTARTSYS) {
 325                 pr_debug("wait_event_interruptible woken by a signal\n");
 326                 result = -ERESTARTSYS;
 327                 goto error;
 328         }
 329
 330         if (result == 0) {
 331                 pr_debug("connect timeout\n");
 332                 caif_disconnect_client(dev_net(dev), &priv->chnl);
 333                 priv->state = CAIF_DISCONNECTED;
 334                 pr_debug("state disconnected\n");
 335                 result = -ETIMEDOUT;
 336                 goto error;
 337         }
 338
 339         if (priv->state != CAIF_CONNECTED) {
 340                 pr_debug("connect failed\n");
 341                 result = -ECONNREFUSED;
 342                 goto error;
 343         }
 344         pr_debug("CAIF Netdevice connected\n");
 345         return 0;
 346
 347 error:
 348         caif_disconnect_client(dev_net(dev), &priv->chnl);
 349         priv->state = CAIF_DISCONNECTED;
 350         pr_debug("state disconnected\n");
 351         return result;
 352
 353 }
 354
 355 static int chnl_net_stop(struct net_device *dev)
 356 {
 357         struct chnl_net *priv;
 358
 359         ASSERT_RTNL();
 360         priv = netdev_priv(dev);
 361         priv->state = CAIF_DISCONNECTED;
 362         caif_disconnect_client(dev_net(dev), &priv->chnl);
 363         return 0;
 364 }
 365
 366 static int chnl_net_init(struct net_device *dev)
 367 {
 368         struct chnl_net *priv;
 369         ASSERT_RTNL();
 370         priv = netdev_priv(dev);
 371         strncpy(priv->name, dev->name, sizeof(priv->name));
 372         return 0;
 373 }
 374
 375 static void chnl_net_uninit(struct net_device *dev)
 376 {
 377         struct chnl_net *priv;
 378         ASSERT_RTNL();
 379         priv = netdev_priv(dev);
 380         robust_list_del(&priv->list_field);
 381 }
 382
 383 static const struct net_device_ops netdev_ops = {
 384         .ndo_open = chnl_net_open,
 385         .ndo_stop = chnl_net_stop,
 386         .ndo_init = chnl_net_init,
 387         .ndo_uninit = chnl_net_uninit,
 388         .ndo_start_xmit = chnl_net_start_xmit,
 389 };
 390
 391 static void chnl_net_destructor(struct net_device *dev)
 392 {
 393         struct chnl_net *priv = netdev_priv(dev);
 394         caif_free_client(&priv->chnl);
 395         free_netdev(dev);
 396 }
 397
 398 static void ipcaif_net_setup(struct net_device *dev)
 399 {
 400         struct chnl_net *priv;
 401         dev->netdev_ops = &netdev_ops;
 402         dev->destructor = chnl_net_destructor;
 403         dev->flags |= IFF_NOARP;
 404         dev->flags |= IFF_POINTOPOINT;
 405         dev->mtu = GPRS_PDP_MTU;
 406         dev->tx_queue_len = CAIF_NET_DEFAULT_QUEUE_LEN;
 407
 408         priv = netdev_priv(dev);
 409         priv->chnl.receive = chnl_recv_cb;
 410         priv->chnl.ctrlcmd = chnl_flowctrl_cb;
 411         priv->netdev = dev;
 412         priv->conn_req.protocol = CAIFPROTO_DATAGRAM;
 413         priv->conn_req.link_selector = CAIF_LINK_HIGH_BANDW;
 414         priv->conn_req.priority = CAIF_PRIO_LOW;
 415         /* Insert illegal value */
 416         priv->conn_req.sockaddr.u.dgm.connection_id = UNDEF_CONNID;
 417         priv->flowenabled = false;
 418
 419         init_waitqueue_head(&priv->netmgmt_wq);
 420 }
 421
 422
 423 static int ipcaif_fill_info(struct sk_buff *skb, const struct net_device *dev)
 424 {
 425         struct chnl_net *priv;
 426         u8 loop;
 427         priv = netdev_priv(dev);
 428         if (nla_put_u32(skb, IFLA_CAIF_IPV4_CONNID,
 429                         priv->conn_req.sockaddr.u.dgm.connection_id) ||
 430             nla_put_u32(skb, IFLA_CAIF_IPV6_CONNID,
 431                         priv->conn_req.sockaddr.u.dgm.connection_id))
 432                 goto nla_put_failure;
 433         loop = priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP;
 434         if (nla_put_u8(skb, IFLA_CAIF_LOOPBACK, loop))
 435                 goto nla_put_failure;
 436         return 0;
 437 nla_put_failure:
 438         return -EMSGSIZE;
 439
 440 }
 441
 442 static void caif_netlink_parms(struct nlattr *data[],
 443                                struct caif_connect_request *conn_req)
 444 {
 445         if (!data) {
 446                 pr_warn("no params data found\n");
 447                 return;
 448         }
 449         if (data[IFLA_CAIF_IPV4_CONNID])
 450                 conn_req->sockaddr.u.dgm.connection_id =
 451                         nla_get_u32(data[IFLA_CAIF_IPV4_CONNID]);
 452         if (data[IFLA_CAIF_IPV6_CONNID])
 453                 conn_req->sockaddr.u.dgm.connection_id =
 454                         nla_get_u32(data[IFLA_CAIF_IPV6_CONNID]);
 455         if (data[IFLA_CAIF_LOOPBACK]) {
 456                 if (nla_get_u8(data[IFLA_CAIF_LOOPBACK]))
 457                         conn_req->protocol = CAIFPROTO_DATAGRAM_LOOP;
 458                 else
 459                         conn_req->protocol = CAIFPROTO_DATAGRAM;
 460         }
 461 }
 462
 463 static int ipcaif_newlink(struct net *src_net, struct net_device *dev,
 464                           struct nlattr *tb[], struct nlattr *data[])
 465 {
 466         int ret;
 467         struct chnl_net *caifdev;
 468         ASSERT_RTNL();
 469         caifdev = netdev_priv(dev);
 470         caif_netlink_parms(data, &caifdev->conn_req);
 471
 472         ret = register_netdevice(dev);
 473         if (ret)
 474                 pr_warn("device rtml registration failed\n");
 475         else
 476                 list_add(&caifdev->list_field, &chnl_net_list);
 477
 478         /* Use ifindex as connection id, and use loopback channel default. */
 479         if (caifdev->conn_req.sockaddr.u.dgm.connection_id == UNDEF_CONNID) {
 480                 caifdev->conn_req.sockaddr.u.dgm.connection_id = dev->ifindex;
 481                 caifdev->conn_req.protocol = CAIFPROTO_DATAGRAM_LOOP;
 482         }
 483         return ret;
 484 }
 485
 486 static int ipcaif_changelink(struct net_device *dev, struct nlattr *tb[],
 487                              struct nlattr *data[])
 488 {
 489         struct chnl_net *caifdev;
 490         ASSERT_RTNL();
 491         caifdev = netdev_priv(dev);
 492         caif_netlink_parms(data, &caifdev->conn_req);
 493         netdev_state_change(dev);
 494         return 0;
 495 }
 496
 497 static size_t ipcaif_get_size(const struct net_device *dev)
 498 {
 499         return
 500                 /* IFLA_CAIF_IPV4_CONNID */
 501                 nla_total_size(4) +
 502                 /* IFLA_CAIF_IPV6_CONNID */
 503                 nla_total_size(4) +
 504                 /* IFLA_CAIF_LOOPBACK */
 505                 nla_total_size(2) +
 506                 0;
 507 }
 508
 509 static const struct nla_policy ipcaif_policy[IFLA_CAIF_MAX + 1] = {
 510         [IFLA_CAIF_IPV4_CONNID]       = { .type = NLA_U32 },
 511         [IFLA_CAIF_IPV6_CONNID]       = { .type = NLA_U32 },
 512         [IFLA_CAIF_LOOPBACK]          = { .type = NLA_U8 }
 513 };
 514
 515
 516 static struct rtnl_link_ops ipcaif_link_ops __read_mostly = {
 517         .kind           = "caif",
 518         .priv_size      = sizeof(struct chnl_net),
 519         .setup          = ipcaif_net_setup,
 520         .maxtype        = IFLA_CAIF_MAX,
 521         .policy         = ipcaif_policy,
 522         .newlink        = ipcaif_newlink,
 523         .changelink     = ipcaif_changelink,
 524         .get_size       = ipcaif_get_size,
 525         .fill_info      = ipcaif_fill_info,
 526
 527 };
 528
 529 static int __init chnl_init_module(void)
 530 {
 531         return rtnl_link_register(&ipcaif_link_ops);
 532 }
 533
 534 static void __exit chnl_exit_module(void)
 535 {
 536         struct chnl_net *dev = NULL;
 537         struct list_head *list_node;
 538         struct list_head *_tmp;
 539         rtnl_link_unregister(&ipcaif_link_ops);
 540         rtnl_lock();
 541         list_for_each_safe(list_node, _tmp, &chnl_net_list) {
 542                 dev = list_entry(list_node, struct chnl_net, list_field);
 543                 list_del(list_node);
 544                 delete_device(dev);
 545         }
 546         rtnl_unlock();
 547 }
 548
 549 module_init(chnl_init_module);
 550 module_exit(chnl_exit_module);