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/moduleparam.h>
  17 #include <linux/ip.h>
  18 #include <linux/sched.h>
  19 #include <linux/sockios.h>
  20 #include <linux/caif/if_caif.h>
  21 #include <net/rtnetlink.h>
  22 #include <net/caif/caif_layer.h>
  23 #include <net/caif/cfpkt.h>
  24 #include <net/caif/caif_dev.h>
  25
  26 /* GPRS PDP connection has MTU to 1500 */
  27 #define GPRS_PDP_MTU 1500
  28 /* 5 sec. connect timeout */
  29 #define CONNECT_TIMEOUT (5 * HZ)
  30 #define CAIF_NET_DEFAULT_QUEUE_LEN 500
  31 #define UNDEF_CONNID 0xffffffff
  32
  33 /*This list is protected by the rtnl lock. */
  34 static LIST_HEAD(chnl_net_list);
  35
  36 MODULE_LICENSE("GPL");
  37 MODULE_ALIAS_RTNL_LINK("caif");
  38
  39 enum caif_states {
  40         CAIF_CONNECTED          = 1,
  41         CAIF_CONNECTING,
  42         CAIF_DISCONNECTED,
  43         CAIF_SHUTDOWN
  44 };
  45
  46 struct chnl_net {
  47         struct cflayer chnl;
  48         struct net_device_stats stats;
  49         struct caif_connect_request conn_req;
  50         struct list_head list_field;
  51         struct net_device *netdev;
  52         char name[256];
  53         wait_queue_head_t netmgmt_wq;
  54         /* Flow status to remember and control the transmission. */
  55         bool flowenabled;
  56         enum caif_states state;
  57 };
  58
  59 static void robust_list_del(struct list_head *delete_node)
  60 {
  61         struct list_head *list_node;
  62         struct list_head *n;
  63         ASSERT_RTNL();
  64         list_for_each_safe(list_node, n, &chnl_net_list) {
  65                 if (list_node == delete_node) {
  66                         list_del(list_node);
  67                         return;
  68                 }
  69         }
  70         WARN_ON(1);
  71 }
  72
  73 static int chnl_recv_cb(struct cflayer *layr, struct cfpkt *pkt)
  74 {
  75         struct sk_buff *skb;
  76         struct chnl_net *priv;
  77         int pktlen;
  78         const u8 *ip_version;
  79         u8 buf;
  80
  81         priv = container_of(layr, struct chnl_net, chnl);
  82         if (!priv)
  83                 return -EINVAL;
  84
  85         skb = (struct sk_buff *) cfpkt_tonative(pkt);
  86
  87         /* Get length of CAIF packet. */
  88         pktlen = skb->len;
  89
  90         /* Pass some minimum information and
  91          * send the packet to the net stack.
  92          */
  93         skb->dev = priv->netdev;
  94
  95         /* check the version of IP */
  96         ip_version = skb_header_pointer(skb, 0, 1, &buf);
  97         if (!ip_version) {
  98                 kfree_skb(skb);
  99                 return -EINVAL;
 100         }
 101
 102         switch (*ip_version >> 4) {
 103         case 4:
 104                 skb->protocol = htons(ETH_P_IP);
 105                 break;
 106         case 6:
 107                 skb->protocol = htons(ETH_P_IPV6);
 108                 break;
 109         default:
 110                 kfree_skb(skb);
 111                 priv->netdev->stats.rx_errors++;
 112                 return -EINVAL;
 113         }
 114
 115         /* If we change the header in loop mode, the checksum is corrupted. */
 116         if (priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP)
 117                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 118         else
 119                 skb->ip_summed = CHECKSUM_NONE;
 120
 121         if (in_interrupt())
 122                 netif_rx(skb);
 123         else
 124                 netif_rx_ni(skb);
 125
 126         /* Update statistics. */
 127         priv->netdev->stats.rx_packets++;
 128         priv->netdev->stats.rx_bytes += pktlen;
 129
 130         return 0;
 131 }
 132
 133 static int delete_device(struct chnl_net *dev)
 134 {
 135         ASSERT_RTNL();
 136         if (dev->netdev)
 137                 unregister_netdevice(dev->netdev);
 138         return 0;
 139 }
 140
 141 static void close_work(struct work_struct *work)
 142 {
 143         struct chnl_net *dev = NULL;
 144         struct list_head *list_node;
 145         struct list_head *_tmp;
 146
 147         rtnl_lock();
 148         list_for_each_safe(list_node, _tmp, &chnl_net_list) {
 149                 dev = list_entry(list_node, struct chnl_net, list_field);
 150                 if (dev->state == CAIF_SHUTDOWN)
 151                         dev_close(dev->netdev);
 152         }
 153         rtnl_unlock();
 154 }
 155 static DECLARE_WORK(close_worker, close_work);
 156
 157 static void chnl_hold(struct cflayer *lyr)
 158 {
 159         struct chnl_net *priv = container_of(lyr, struct chnl_net, chnl);
 160         dev_hold(priv->netdev);
 161 }
 162
 163 static void chnl_put(struct cflayer *lyr)
 164 {
 165         struct chnl_net *priv = container_of(lyr, struct chnl_net, chnl);
 166         dev_put(priv->netdev);
 167 }
 168
 169 static void chnl_flowctrl_cb(struct cflayer *layr, enum caif_ctrlcmd flow,
 170                              int phyid)
 171 {
 172         struct chnl_net *priv = container_of(layr, struct chnl_net, chnl);
 173         pr_debug("NET flowctrl func called flow: %s\n",
 174                 flow == CAIF_CTRLCMD_FLOW_ON_IND ? "ON" :
 175                 flow == CAIF_CTRLCMD_INIT_RSP ? "INIT" :
 176                 flow == CAIF_CTRLCMD_FLOW_OFF_IND ? "OFF" :
 177                 flow == CAIF_CTRLCMD_DEINIT_RSP ? "CLOSE/DEINIT" :
 178                 flow == CAIF_CTRLCMD_INIT_FAIL_RSP ? "OPEN_FAIL" :
 179                 flow == CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND ?
 180                  "REMOTE_SHUTDOWN" : "UKNOWN CTRL COMMAND");
 181
 182
 183
 184         switch (flow) {
 185         case CAIF_CTRLCMD_FLOW_OFF_IND:
 186                 priv->flowenabled = false;
 187                 netif_stop_queue(priv->netdev);
 188                 break;
 189         case CAIF_CTRLCMD_DEINIT_RSP:
 190                 priv->state = CAIF_DISCONNECTED;
 191                 break;
 192         case CAIF_CTRLCMD_INIT_FAIL_RSP:
 193                 priv->state = CAIF_DISCONNECTED;
 194                 wake_up_interruptible(&priv->netmgmt_wq);
 195                 break;
 196         case CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND:
 197                 priv->state = CAIF_SHUTDOWN;
 198                 netif_tx_disable(priv->netdev);
 199                 schedule_work(&close_worker);
 200                 break;
 201         case CAIF_CTRLCMD_FLOW_ON_IND:
 202                 priv->flowenabled = true;
 203                 netif_wake_queue(priv->netdev);
 204                 break;
 205         case CAIF_CTRLCMD_INIT_RSP:
 206                 caif_client_register_refcnt(&priv->chnl, chnl_hold, chnl_put);
 207                 priv->state = CAIF_CONNECTED;
 208                 priv->flowenabled = true;
 209                 netif_wake_queue(priv->netdev);
 210                 wake_up_interruptible(&priv->netmgmt_wq);
 211                 break;
 212         default:
 213                 break;
 214         }
 215 }
 216
 217 static int chnl_net_start_xmit(struct sk_buff *skb, struct net_device *dev)
 218 {
 219         struct chnl_net *priv;
 220         struct cfpkt *pkt = NULL;
 221         int len;
 222         int result = -1;
 223         /* Get our private data. */
 224         priv = netdev_priv(dev);
 225
 226         if (skb->len > priv->netdev->mtu) {
 227                 pr_warn("Size of skb exceeded MTU\n");
 228                 kfree_skb(skb);
 229                 dev->stats.tx_errors++;
 230                 return NETDEV_TX_OK;
 231         }
 232
 233         if (!priv->flowenabled) {
 234                 pr_debug("dropping packets flow off\n");
 235                 kfree_skb(skb);
 236                 dev->stats.tx_dropped++;
 237                 return NETDEV_TX_OK;
 238         }
 239
 240         if (priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP)
 241                 swap(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr);
 242
 243         /* Store original SKB length. */
 244         len = skb->len;
 245
 246         pkt = cfpkt_fromnative(CAIF_DIR_OUT, (void *) skb);
 247
 248         /* Send the packet down the stack. */
 249         result = priv->chnl.dn->transmit(priv->chnl.dn, pkt);
 250         if (result) {
 251                 dev->stats.tx_dropped++;
 252                 return NETDEV_TX_OK;
 253         }
 254
 255         /* Update statistics. */
 256         dev->stats.tx_packets++;
 257         dev->stats.tx_bytes += len;
 258
 259         return NETDEV_TX_OK;
 260 }
 261
 262 static int chnl_net_open(struct net_device *dev)
 263 {
 264         struct chnl_net *priv = NULL;
 265         int result = -1;
 266         int llifindex, headroom, tailroom, mtu;
 267         struct net_device *lldev;
 268         ASSERT_RTNL();
 269         priv = netdev_priv(dev);
 270         if (!priv) {
 271                 pr_debug("chnl_net_open: no priv\n");
 272                 return -ENODEV;
 273         }
 274
 275         if (priv->state != CAIF_CONNECTING) {
 276                 priv->state = CAIF_CONNECTING;
 277                 result = caif_connect_client(dev_net(dev), &priv->conn_req,
 278                                                 &priv->chnl, &llifindex,
 279                                                 &headroom, &tailroom);
 280                 if (result != 0) {
 281                                 pr_debug("err: "
 282                                          "Unable to register and open device,"
 283                                          " Err:%d\n",
 284                                          result);
 285                                 goto error;
 286                 }
 287
 288                 lldev = dev_get_by_index(dev_net(dev), llifindex);
 289
 290                 if (lldev == NULL) {
 291                         pr_debug("no interface?\n");
 292                         result = -ENODEV;
 293                         goto error;
 294                 }
 295
 296                 dev->needed_tailroom = tailroom + lldev->needed_tailroom;
 297                 dev->hard_header_len = headroom + lldev->hard_header_len +
 298                         lldev->needed_tailroom;
 299
 300                 /*
 301                  * MTU, head-room etc is not know before we have a
 302                  * CAIF link layer device available. MTU calculation may
 303                  * override initial RTNL configuration.
 304                  * MTU is minimum of current mtu, link layer mtu pluss
 305                  * CAIF head and tail, and PDP GPRS contexts max MTU.
 306                  */
 307                 mtu = min_t(int, dev->mtu, lldev->mtu - (headroom + tailroom));
 308                 mtu = min_t(int, GPRS_PDP_MTU, mtu);
 309                 dev_set_mtu(dev, mtu);
 310                 dev_put(lldev);
 311
 312                 if (mtu < 100) {
 313                         pr_warn("CAIF Interface MTU too small (%d)\n", mtu);
 314                         result = -ENODEV;
 315                         goto error;
 316                 }
 317         }
 318
 319         rtnl_unlock();  /* Release RTNL lock during connect wait */
 320
 321         result = wait_event_interruptible_timeout(priv->netmgmt_wq,
 322                                                 priv->state != CAIF_CONNECTING,
 323                                                 CONNECT_TIMEOUT);
 324
 325         rtnl_lock();
 326
 327         if (result == -ERESTARTSYS) {
 328                 pr_debug("wait_event_interruptible woken by a signal\n");
 329                 result = -ERESTARTSYS;
 330                 goto error;
 331         }
 332
 333         if (result == 0) {
 334                 pr_debug("connect timeout\n");
 335                 caif_disconnect_client(dev_net(dev), &priv->chnl);
 336                 priv->state = CAIF_DISCONNECTED;
 337                 pr_debug("state disconnected\n");
 338                 result = -ETIMEDOUT;
 339                 goto error;
 340         }
 341
 342         if (priv->state != CAIF_CONNECTED) {
 343                 pr_debug("connect failed\n");
 344                 result = -ECONNREFUSED;
 345                 goto error;
 346         }
 347         pr_debug("CAIF Netdevice connected\n");
 348         return 0;
 349
 350 error:
 351         caif_disconnect_client(dev_net(dev), &priv->chnl);
 352         priv->state = CAIF_DISCONNECTED;
 353         pr_debug("state disconnected\n");
 354         return result;
 355
 356 }
 357
 358 static int chnl_net_stop(struct net_device *dev)
 359 {
 360         struct chnl_net *priv;
 361
 362         ASSERT_RTNL();
 363         priv = netdev_priv(dev);
 364         priv->state = CAIF_DISCONNECTED;
 365         caif_disconnect_client(dev_net(dev), &priv->chnl);
 366         return 0;
 367 }
 368
 369 static int chnl_net_init(struct net_device *dev)
 370 {
 371         struct chnl_net *priv;
 372         ASSERT_RTNL();
 373         priv = netdev_priv(dev);
 374         strncpy(priv->name, dev->name, sizeof(priv->name));
 375         return 0;
 376 }
 377
 378 static void chnl_net_uninit(struct net_device *dev)
 379 {
 380         struct chnl_net *priv;
 381         ASSERT_RTNL();
 382         priv = netdev_priv(dev);
 383         robust_list_del(&priv->list_field);
 384 }
 385
 386 static const struct net_device_ops netdev_ops = {
 387         .ndo_open = chnl_net_open,
 388         .ndo_stop = chnl_net_stop,
 389         .ndo_init = chnl_net_init,
 390         .ndo_uninit = chnl_net_uninit,
 391         .ndo_start_xmit = chnl_net_start_xmit,
 392 };
 393
 394 static void chnl_net_destructor(struct net_device *dev)
 395 {
 396         struct chnl_net *priv = netdev_priv(dev);
 397         caif_free_client(&priv->chnl);
 398         free_netdev(dev);
 399 }
 400
 401 static void ipcaif_net_setup(struct net_device *dev)
 402 {
 403         struct chnl_net *priv;
 404         dev->netdev_ops = &netdev_ops;
 405         dev->destructor = chnl_net_destructor;
 406         dev->flags |= IFF_NOARP;
 407         dev->flags |= IFF_POINTOPOINT;
 408         dev->mtu = GPRS_PDP_MTU;
 409         dev->tx_queue_len = CAIF_NET_DEFAULT_QUEUE_LEN;
 410
 411         priv = netdev_priv(dev);
 412         priv->chnl.receive = chnl_recv_cb;
 413         priv->chnl.ctrlcmd = chnl_flowctrl_cb;
 414         priv->netdev = dev;
 415         priv->conn_req.protocol = CAIFPROTO_DATAGRAM;
 416         priv->conn_req.link_selector = CAIF_LINK_HIGH_BANDW;
 417         priv->conn_req.priority = CAIF_PRIO_LOW;
 418         /* Insert illegal value */
 419         priv->conn_req.sockaddr.u.dgm.connection_id = UNDEF_CONNID;
 420         priv->flowenabled = false;
 421
 422         init_waitqueue_head(&priv->netmgmt_wq);
 423 }
 424
 425
 426 static int ipcaif_fill_info(struct sk_buff *skb, const struct net_device *dev)
 427 {
 428         struct chnl_net *priv;
 429         u8 loop;
 430         priv = netdev_priv(dev);
 431         if (nla_put_u32(skb, IFLA_CAIF_IPV4_CONNID,
 432                         priv->conn_req.sockaddr.u.dgm.connection_id) ||
 433             nla_put_u32(skb, IFLA_CAIF_IPV6_CONNID,
 434                         priv->conn_req.sockaddr.u.dgm.connection_id))
 435                 goto nla_put_failure;
 436         loop = priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP;
 437         if (nla_put_u8(skb, IFLA_CAIF_LOOPBACK, loop))
 438                 goto nla_put_failure;
 439         return 0;
 440 nla_put_failure:
 441         return -EMSGSIZE;
 442
 443 }
 444
 445 static void caif_netlink_parms(struct nlattr *data[],
 446                                struct caif_connect_request *conn_req)
 447 {
 448         if (!data) {
 449                 pr_warn("no params data found\n");
 450                 return;
 451         }
 452         if (data[IFLA_CAIF_IPV4_CONNID])
 453                 conn_req->sockaddr.u.dgm.connection_id =
 454                         nla_get_u32(data[IFLA_CAIF_IPV4_CONNID]);
 455         if (data[IFLA_CAIF_IPV6_CONNID])
 456                 conn_req->sockaddr.u.dgm.connection_id =
 457                         nla_get_u32(data[IFLA_CAIF_IPV6_CONNID]);
 458         if (data[IFLA_CAIF_LOOPBACK]) {
 459                 if (nla_get_u8(data[IFLA_CAIF_LOOPBACK]))
 460                         conn_req->protocol = CAIFPROTO_DATAGRAM_LOOP;
 461                 else
 462                         conn_req->protocol = CAIFPROTO_DATAGRAM;
 463         }
 464 }
 465
 466 static int ipcaif_newlink(struct net *src_net, struct net_device *dev,
 467                           struct nlattr *tb[], struct nlattr *data[])
 468 {
 469         int ret;
 470         struct chnl_net *caifdev;
 471         ASSERT_RTNL();
 472         caifdev = netdev_priv(dev);
 473         caif_netlink_parms(data, &caifdev->conn_req);
 474         dev_net_set(caifdev->netdev, src_net);
 475
 476         ret = register_netdevice(dev);
 477         if (ret)
 478                 pr_warn("device rtml registration failed\n");
 479         else
 480                 list_add(&caifdev->list_field, &chnl_net_list);
 481
 482         /* Use ifindex as connection id, and use loopback channel default. */
 483         if (caifdev->conn_req.sockaddr.u.dgm.connection_id == UNDEF_CONNID) {
 484                 caifdev->conn_req.sockaddr.u.dgm.connection_id = dev->ifindex;
 485                 caifdev->conn_req.protocol = CAIFPROTO_DATAGRAM_LOOP;
 486         }
 487         return ret;
 488 }
 489
 490 static int ipcaif_changelink(struct net_device *dev, struct nlattr *tb[],
 491                              struct nlattr *data[])
 492 {
 493         struct chnl_net *caifdev;
 494         ASSERT_RTNL();
 495         caifdev = netdev_priv(dev);
 496         caif_netlink_parms(data, &caifdev->conn_req);
 497         netdev_state_change(dev);
 498         return 0;
 499 }
 500
 501 static size_t ipcaif_get_size(const struct net_device *dev)
 502 {
 503         return
 504                 /* IFLA_CAIF_IPV4_CONNID */
 505                 nla_total_size(4) +
 506                 /* IFLA_CAIF_IPV6_CONNID */
 507                 nla_total_size(4) +
 508                 /* IFLA_CAIF_LOOPBACK */
 509                 nla_total_size(2) +
 510                 0;
 511 }
 512
 513 static const struct nla_policy ipcaif_policy[IFLA_CAIF_MAX + 1] = {
 514         [IFLA_CAIF_IPV4_CONNID]       = { .type = NLA_U32 },
 515         [IFLA_CAIF_IPV6_CONNID]       = { .type = NLA_U32 },
 516         [IFLA_CAIF_LOOPBACK]          = { .type = NLA_U8 }
 517 };
 518
 519
 520 static struct rtnl_link_ops ipcaif_link_ops __read_mostly = {
 521         .kind           = "caif",
 522         .priv_size      = sizeof(struct chnl_net),
 523         .setup          = ipcaif_net_setup,
 524         .maxtype        = IFLA_CAIF_MAX,
 525         .policy         = ipcaif_policy,
 526         .newlink        = ipcaif_newlink,
 527         .changelink     = ipcaif_changelink,
 528         .get_size       = ipcaif_get_size,
 529         .fill_info      = ipcaif_fill_info,
 530
 531 };
 532
 533 static int __init chnl_init_module(void)
 534 {
 535         return rtnl_link_register(&ipcaif_link_ops);
 536 }
 537
 538 static void __exit chnl_exit_module(void)
 539 {
 540         struct chnl_net *dev = NULL;
 541         struct list_head *list_node;
 542         struct list_head *_tmp;
 543         rtnl_link_unregister(&ipcaif_link_ops);
 544         rtnl_lock();
 545         list_for_each_safe(list_node, _tmp, &chnl_net_list) {
 546                 dev = list_entry(list_node, struct chnl_net, list_field);
 547                 list_del(list_node);
 548                 delete_device(dev);
 549         }
 550         rtnl_unlock();
 551 }
 552
 553 module_init(chnl_init_module);
 554 module_exit(chnl_exit_module);