net/caif/chnl_net.c

   1 /*
   2  * Copyright (C) ST-Ericsson AB 2010
   3  * Authors:     Sjur Brendeland/sjur.brandeland@stericsson.com
   4  *              Daniel Martensson / Daniel.Martensson@stericsson.com
   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/version.h>
  11 #include <linux/fs.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/cfcnfg.h>
  24 #include <net/caif/cfpkt.h>
  25 #include <net/caif/caif_dev.h>
  26
  27 /* GPRS PDP connection has MTU to 1500 */
  28 #define GPRS_PDP_MTU 1500
  29 /* 5 sec. connect timeout */
  30 #define CONNECT_TIMEOUT (5 * HZ)
  31 #define CAIF_NET_DEFAULT_QUEUE_LEN 500
  32
  33 #undef pr_debug
  34 #define pr_debug pr_warn
  35
  36 /*This list is protected by the rtnl lock. */
  37 static LIST_HEAD(chnl_net_list);
  38
  39 MODULE_LICENSE("GPL");
  40 MODULE_ALIAS_RTNL_LINK("caif");
  41
  42 enum caif_states {
  43         CAIF_CONNECTED          = 1,
  44         CAIF_CONNECTING,
  45         CAIF_DISCONNECTED,
  46         CAIF_SHUTDOWN
  47 };
  48
  49 struct chnl_net {
  50         struct cflayer chnl;
  51         struct net_device_stats stats;
  52         struct caif_connect_request conn_req;
  53         struct list_head list_field;
  54         struct net_device *netdev;
  55         char name[256];
  56         wait_queue_head_t netmgmt_wq;
  57         /* Flow status to remember and control the transmission. */
  58         bool flowenabled;
  59         enum caif_states state;
  60 };
  61
  62 static void robust_list_del(struct list_head *delete_node)
  63 {
  64         struct list_head *list_node;
  65         struct list_head *n;
  66         ASSERT_RTNL();
  67         list_for_each_safe(list_node, n, &chnl_net_list) {
  68                 if (list_node == delete_node) {
  69                         list_del(list_node);
  70                         return;
  71                 }
  72         }
  73         WARN_ON(1);
  74 }
  75
  76 static int chnl_recv_cb(struct cflayer *layr, struct cfpkt *pkt)
  77 {
  78         struct sk_buff *skb;
  79         struct chnl_net *priv  = container_of(layr, struct chnl_net, chnl);
  80         int pktlen;
  81         int err = 0;
  82
  83         priv = container_of(layr, struct chnl_net, chnl);
  84
  85         if (!priv)
  86                 return -EINVAL;
  87
  88         /* Get length of CAIF packet. */
  89         pktlen = cfpkt_getlen(pkt);
  90
  91         skb = (struct sk_buff *) cfpkt_tonative(pkt);
  92         /* Pass some minimum information and
  93          * send the packet to the net stack.
  94          */
  95         skb->dev = priv->netdev;
  96         skb->protocol = htons(ETH_P_IP);
  97
  98         /* If we change the header in loop mode, the checksum is corrupted. */
  99         if (priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP)
 100                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 101         else
 102                 skb->ip_summed = CHECKSUM_NONE;
 103
 104         if (in_interrupt())
 105                 netif_rx(skb);
 106         else
 107                 netif_rx_ni(skb);
 108
 109         /* Update statistics. */
 110         priv->netdev->stats.rx_packets++;
 111         priv->netdev->stats.rx_bytes += pktlen;
 112
 113         return err;
 114 }
 115
 116 static int delete_device(struct chnl_net *dev)
 117 {
 118         ASSERT_RTNL();
 119         if (dev->netdev)
 120                 unregister_netdevice(dev->netdev);
 121         return 0;
 122 }
 123
 124 static void close_work(struct work_struct *work)
 125 {
 126         struct chnl_net *dev = NULL;
 127         struct list_head *list_node;
 128         struct list_head *_tmp;
 129         /* May be called with or without RTNL lock held */
 130         int islocked = rtnl_is_locked();
 131         if (!islocked)
 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         if (!islocked)
 139                 rtnl_unlock();
 140 }
 141 static DECLARE_WORK(close_worker, close_work);
 142
 143 static void chnl_flowctrl_cb(struct cflayer *layr, enum caif_ctrlcmd flow,
 144                                 int phyid)
 145 {
 146         struct chnl_net *priv = container_of(layr, struct chnl_net, chnl);
 147         pr_debug("NET flowctrl func called flow: %s\n",
 148                 flow == CAIF_CTRLCMD_FLOW_ON_IND ? "ON" :
 149                 flow == CAIF_CTRLCMD_INIT_RSP ? "INIT" :
 150                 flow == CAIF_CTRLCMD_FLOW_OFF_IND ? "OFF" :
 151                 flow == CAIF_CTRLCMD_DEINIT_RSP ? "CLOSE/DEINIT" :
 152                 flow == CAIF_CTRLCMD_INIT_FAIL_RSP ? "OPEN_FAIL" :
 153                 flow == CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND ?
 154                  "REMOTE_SHUTDOWN" : "UKNOWN CTRL COMMAND");
 155
 156
 157
 158         switch (flow) {
 159         case CAIF_CTRLCMD_FLOW_OFF_IND:
 160                 priv->flowenabled = false;
 161                 netif_stop_queue(priv->netdev);
 162                 break;
 163         case CAIF_CTRLCMD_DEINIT_RSP:
 164                 priv->state = CAIF_DISCONNECTED;
 165                 break;
 166         case CAIF_CTRLCMD_INIT_FAIL_RSP:
 167                 priv->state = CAIF_DISCONNECTED;
 168                 wake_up_interruptible(&priv->netmgmt_wq);
 169                 break;
 170         case CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND:
 171                 priv->state = CAIF_SHUTDOWN;
 172                 netif_tx_disable(priv->netdev);
 173                 schedule_work(&close_worker);
 174                 break;
 175         case CAIF_CTRLCMD_FLOW_ON_IND:
 176                 priv->flowenabled = true;
 177                 netif_wake_queue(priv->netdev);
 178                 break;
 179         case CAIF_CTRLCMD_INIT_RSP:
 180                 priv->state = CAIF_CONNECTED;
 181                 priv->flowenabled = true;
 182                 netif_wake_queue(priv->netdev);
 183                 wake_up_interruptible(&priv->netmgmt_wq);
 184                 break;
 185         default:
 186                 break;
 187         }
 188 }
 189
 190 static int chnl_net_start_xmit(struct sk_buff *skb, struct net_device *dev)
 191 {
 192         struct chnl_net *priv;
 193         struct cfpkt *pkt = NULL;
 194         int len;
 195         int result = -1;
 196         /* Get our private data. */
 197         priv = netdev_priv(dev);
 198
 199         if (skb->len > priv->netdev->mtu) {
 200                 pr_warn("Size of skb exceeded MTU\n");
 201                 return -ENOSPC;
 202         }
 203
 204         if (!priv->flowenabled) {
 205                 pr_debug("dropping packets flow off\n");
 206                 return NETDEV_TX_BUSY;
 207         }
 208
 209         if (priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP)
 210                 swap(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr);
 211
 212         /* Store original SKB length. */
 213         len = skb->len;
 214
 215         pkt = cfpkt_fromnative(CAIF_DIR_OUT, (void *) skb);
 216
 217         /* Send the packet down the stack. */
 218         result = priv->chnl.dn->transmit(priv->chnl.dn, pkt);
 219         if (result) {
 220                 if (result == -EAGAIN)
 221                         result = NETDEV_TX_BUSY;
 222                 return result;
 223         }
 224
 225         /* Update statistics. */
 226         dev->stats.tx_packets++;
 227         dev->stats.tx_bytes += len;
 228
 229         return NETDEV_TX_OK;
 230 }
 231
 232 static int chnl_net_open(struct net_device *dev)
 233 {
 234         struct chnl_net *priv = NULL;
 235         int result = -1;
 236         int llifindex, headroom, tailroom, mtu;
 237         struct net_device *lldev;
 238         ASSERT_RTNL();
 239         priv = netdev_priv(dev);
 240         if (!priv) {
 241                 pr_debug("chnl_net_open: no priv\n");
 242                 return -ENODEV;
 243         }
 244
 245         if (priv->state != CAIF_CONNECTING) {
 246                 priv->state = CAIF_CONNECTING;
 247                 result = caif_connect_client(&priv->conn_req, &priv->chnl,
 248                                         &llifindex, &headroom, &tailroom);
 249                 if (result != 0) {
 250                                 pr_debug("err: "
 251                                          "Unable to register and open device,"
 252                                          " Err:%d\n",
 253                                          result);
 254                                 goto error;
 255                 }
 256
 257                 lldev = dev_get_by_index(dev_net(dev), llifindex);
 258
 259                 if (lldev == NULL) {
 260                         pr_debug("no interface?\n");
 261                         result = -ENODEV;
 262                         goto error;
 263                 }
 264
 265                 dev->needed_tailroom = tailroom + lldev->needed_tailroom;
 266                 dev->hard_header_len = headroom + lldev->hard_header_len +
 267                         lldev->needed_tailroom;
 268
 269                 /*
 270                  * MTU, head-room etc is not know before we have a
 271                  * CAIF link layer device available. MTU calculation may
 272                  * override initial RTNL configuration.
 273                  * MTU is minimum of current mtu, link layer mtu pluss
 274                  * CAIF head and tail, and PDP GPRS contexts max MTU.
 275                  */
 276                 mtu = min_t(int, dev->mtu, lldev->mtu - (headroom + tailroom));
 277                 mtu = min_t(int, GPRS_PDP_MTU, mtu);
 278                 dev_set_mtu(dev, mtu);
 279                 dev_put(lldev);
 280
 281                 if (mtu < 100) {
 282                         pr_warn("CAIF Interface MTU too small (%d)\n", mtu);
 283                         result = -ENODEV;
 284                         goto error;
 285                 }
 286         }
 287
 288         rtnl_unlock();  /* Release RTNL lock during connect wait */
 289
 290         result = wait_event_interruptible_timeout(priv->netmgmt_wq,
 291                                                 priv->state != CAIF_CONNECTING,
 292                                                 CONNECT_TIMEOUT);
 293
 294         rtnl_lock();
 295
 296         if (result == -ERESTARTSYS) {
 297                 pr_debug("wait_event_interruptible woken by a signal\n");
 298                 result = -ERESTARTSYS;
 299                 goto error;
 300         }
 301
 302         if (result == 0) {
 303                 pr_debug("connect timeout\n");
 304                 caif_disconnect_client(&priv->chnl);
 305                 priv->state = CAIF_DISCONNECTED;
 306                 pr_debug("state disconnected\n");
 307                 result = -ETIMEDOUT;
 308                 goto error;
 309         }
 310
 311         if (priv->state != CAIF_CONNECTED) {
 312                 pr_debug("connect failed\n");
 313                 result = -ECONNREFUSED;
 314                 goto error;
 315         }
 316         pr_debug("CAIF Netdevice connected\n");
 317         return 0;
 318
 319 error:
 320         caif_disconnect_client(&priv->chnl);
 321         priv->state = CAIF_DISCONNECTED;
 322         pr_debug("state disconnected\n");
 323         return result;
 324
 325 }
 326
 327 static int chnl_net_stop(struct net_device *dev)
 328 {
 329         struct chnl_net *priv;
 330
 331         ASSERT_RTNL();
 332         priv = netdev_priv(dev);
 333         priv->state = CAIF_DISCONNECTED;
 334         caif_disconnect_client(&priv->chnl);
 335         return 0;
 336 }
 337
 338 static int chnl_net_init(struct net_device *dev)
 339 {
 340         struct chnl_net *priv;
 341         ASSERT_RTNL();
 342         priv = netdev_priv(dev);
 343         strncpy(priv->name, dev->name, sizeof(priv->name));
 344         return 0;
 345 }
 346
 347 static void chnl_net_uninit(struct net_device *dev)
 348 {
 349         struct chnl_net *priv;
 350         ASSERT_RTNL();
 351         priv = netdev_priv(dev);
 352         robust_list_del(&priv->list_field);
 353 }
 354
 355 static const struct net_device_ops netdev_ops = {
 356         .ndo_open = chnl_net_open,
 357         .ndo_stop = chnl_net_stop,
 358         .ndo_init = chnl_net_init,
 359         .ndo_uninit = chnl_net_uninit,
 360         .ndo_start_xmit = chnl_net_start_xmit,
 361 };
 362
 363 static void ipcaif_net_setup(struct net_device *dev)
 364 {
 365         struct chnl_net *priv;
 366         dev->netdev_ops = &netdev_ops;
 367         dev->destructor = free_netdev;
 368         dev->flags |= IFF_NOARP;
 369         dev->flags |= IFF_POINTOPOINT;
 370         dev->mtu = GPRS_PDP_MTU;
 371         dev->tx_queue_len = CAIF_NET_DEFAULT_QUEUE_LEN;
 372
 373         priv = netdev_priv(dev);
 374         priv->chnl.receive = chnl_recv_cb;
 375         priv->chnl.ctrlcmd = chnl_flowctrl_cb;
 376         priv->netdev = dev;
 377         priv->conn_req.protocol = CAIFPROTO_DATAGRAM;
 378         priv->conn_req.link_selector = CAIF_LINK_HIGH_BANDW;
 379         priv->conn_req.priority = CAIF_PRIO_LOW;
 380         /* Insert illegal value */
 381         priv->conn_req.sockaddr.u.dgm.connection_id = -1;
 382         priv->flowenabled = false;
 383
 384         ASSERT_RTNL();
 385         init_waitqueue_head(&priv->netmgmt_wq);
 386         list_add(&priv->list_field, &chnl_net_list);
 387 }
 388
 389
 390 static int ipcaif_fill_info(struct sk_buff *skb, const struct net_device *dev)
 391 {
 392         struct chnl_net *priv;
 393         u8 loop;
 394         priv = netdev_priv(dev);
 395         NLA_PUT_U32(skb, IFLA_CAIF_IPV4_CONNID,
 396                     priv->conn_req.sockaddr.u.dgm.connection_id);
 397         NLA_PUT_U32(skb, IFLA_CAIF_IPV6_CONNID,
 398                     priv->conn_req.sockaddr.u.dgm.connection_id);
 399         loop = priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP;
 400         NLA_PUT_U8(skb, IFLA_CAIF_LOOPBACK, loop);
 401
 402
 403         return 0;
 404 nla_put_failure:
 405         return -EMSGSIZE;
 406
 407 }
 408
 409 static void caif_netlink_parms(struct nlattr *data[],
 410                                 struct caif_connect_request *conn_req)
 411 {
 412         if (!data) {
 413                 pr_warn("no params data found\n");
 414                 return;
 415         }
 416         if (data[IFLA_CAIF_IPV4_CONNID])
 417                 conn_req->sockaddr.u.dgm.connection_id =
 418                         nla_get_u32(data[IFLA_CAIF_IPV4_CONNID]);
 419         if (data[IFLA_CAIF_IPV6_CONNID])
 420                 conn_req->sockaddr.u.dgm.connection_id =
 421                         nla_get_u32(data[IFLA_CAIF_IPV6_CONNID]);
 422         if (data[IFLA_CAIF_LOOPBACK]) {
 423                 if (nla_get_u8(data[IFLA_CAIF_LOOPBACK]))
 424                         conn_req->protocol = CAIFPROTO_DATAGRAM_LOOP;
 425                 else
 426                         conn_req->protocol = CAIFPROTO_DATAGRAM;
 427         }
 428 }
 429
 430 static int ipcaif_newlink(struct net *src_net, struct net_device *dev,
 431                           struct nlattr *tb[], struct nlattr *data[])
 432 {
 433         int ret;
 434         struct chnl_net *caifdev;
 435         ASSERT_RTNL();
 436         caifdev = netdev_priv(dev);
 437         caif_netlink_parms(data, &caifdev->conn_req);
 438         dev_net_set(caifdev->netdev, src_net);
 439
 440         ret = register_netdevice(dev);
 441         if (ret)
 442                 pr_warn("device rtml registration failed\n");
 443         return ret;
 444 }
 445
 446 static int ipcaif_changelink(struct net_device *dev, struct nlattr *tb[],
 447                                 struct nlattr *data[])
 448 {
 449         struct chnl_net *caifdev;
 450         ASSERT_RTNL();
 451         caifdev = netdev_priv(dev);
 452         caif_netlink_parms(data, &caifdev->conn_req);
 453         netdev_state_change(dev);
 454         return 0;
 455 }
 456
 457 static size_t ipcaif_get_size(const struct net_device *dev)
 458 {
 459         return
 460                 /* IFLA_CAIF_IPV4_CONNID */
 461                 nla_total_size(4) +
 462                 /* IFLA_CAIF_IPV6_CONNID */
 463                 nla_total_size(4) +
 464                 /* IFLA_CAIF_LOOPBACK */
 465                 nla_total_size(2) +
 466                 0;
 467 }
 468
 469 static const struct nla_policy ipcaif_policy[IFLA_CAIF_MAX + 1] = {
 470         [IFLA_CAIF_IPV4_CONNID]       = { .type = NLA_U32 },
 471         [IFLA_CAIF_IPV6_CONNID]       = { .type = NLA_U32 },
 472         [IFLA_CAIF_LOOPBACK]          = { .type = NLA_U8 }
 473 };
 474
 475
 476 static struct rtnl_link_ops ipcaif_link_ops __read_mostly = {
 477         .kind           = "caif",
 478         .priv_size      = sizeof(struct chnl_net),
 479         .setup          = ipcaif_net_setup,
 480         .maxtype        = IFLA_CAIF_MAX,
 481         .policy         = ipcaif_policy,
 482         .newlink        = ipcaif_newlink,
 483         .changelink     = ipcaif_changelink,
 484         .get_size       = ipcaif_get_size,
 485         .fill_info      = ipcaif_fill_info,
 486
 487 };
 488
 489 static int __init chnl_init_module(void)
 490 {
 491         return rtnl_link_register(&ipcaif_link_ops);
 492 }
 493
 494 static void __exit chnl_exit_module(void)
 495 {
 496         struct chnl_net *dev = NULL;
 497         struct list_head *list_node;
 498         struct list_head *_tmp;
 499         rtnl_link_unregister(&ipcaif_link_ops);
 500         rtnl_lock();
 501         list_for_each_safe(list_node, _tmp, &chnl_net_list) {
 502                 dev = list_entry(list_node, struct chnl_net, list_field);
 503                 list_del(list_node);
 504                 delete_device(dev);
 505         }
 506         rtnl_unlock();
 507 }
 508
 509 module_init(chnl_init_module);
 510 module_exit(chnl_exit_module);