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/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
  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  = container_of(layr, struct chnl_net, chnl);
  76         int pktlen;
  77         int err = 0;
  78         const u8 *ip_version;
  79         u8 buf;
  80
  81         priv = container_of(layr, struct chnl_net, chnl);
  82
  83         if (!priv)
  84                 return -EINVAL;
  85
  86         /* Get length of CAIF packet. */
  87         pktlen = cfpkt_getlen(pkt);
  88
  89         skb = (struct sk_buff *) cfpkt_tonative(pkt);
  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                 return -EINVAL;
  99         switch (*ip_version >> 4) {
 100         case 4:
 101                 skb->protocol = htons(ETH_P_IP);
 102                 break;
 103         case 6:
 104                 skb->protocol = htons(ETH_P_IPV6);
 105                 break;
 106         default:
 107                 return -EINVAL;
 108         }
 109
 110         /* If we change the header in loop mode, the checksum is corrupted. */
 111         if (priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP)
 112                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 113         else
 114                 skb->ip_summed = CHECKSUM_NONE;
 115
 116         if (in_interrupt())
 117                 netif_rx(skb);
 118         else
 119                 netif_rx_ni(skb);
 120
 121         /* Update statistics. */
 122         priv->netdev->stats.rx_packets++;
 123         priv->netdev->stats.rx_bytes += pktlen;
 124
 125         return err;
 126 }
 127
 128 static int delete_device(struct chnl_net *dev)
 129 {
 130         ASSERT_RTNL();
 131         if (dev->netdev)
 132                 unregister_netdevice(dev->netdev);
 133         return 0;
 134 }
 135
 136 static void close_work(struct work_struct *work)
 137 {
 138         struct chnl_net *dev = NULL;
 139         struct list_head *list_node;
 140         struct list_head *_tmp;
 141         /* May be called with or without RTNL lock held */
 142         int islocked = rtnl_is_locked();
 143         if (!islocked)
 144                 rtnl_lock();
 145         list_for_each_safe(list_node, _tmp, &chnl_net_list) {
 146                 dev = list_entry(list_node, struct chnl_net, list_field);
 147                 if (dev->state == CAIF_SHUTDOWN)
 148                         dev_close(dev->netdev);
 149         }
 150         if (!islocked)
 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                 return -ENOSPC;
 227         }
 228
 229         if (!priv->flowenabled) {
 230                 pr_debug("dropping packets flow off\n");
 231                 return NETDEV_TX_BUSY;
 232         }
 233
 234         if (priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP)
 235                 swap(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr);
 236
 237         /* Store original SKB length. */
 238         len = skb->len;
 239
 240         pkt = cfpkt_fromnative(CAIF_DIR_OUT, (void *) skb);
 241
 242         /* Send the packet down the stack. */
 243         result = priv->chnl.dn->transmit(priv->chnl.dn, pkt);
 244         if (result) {
 245                 if (result == -EAGAIN)
 246                         result = NETDEV_TX_BUSY;
 247                 return result;
 248         }
 249
 250         /* Update statistics. */
 251         dev->stats.tx_packets++;
 252         dev->stats.tx_bytes += len;
 253
 254         return NETDEV_TX_OK;
 255 }
 256
 257 static int chnl_net_open(struct net_device *dev)
 258 {
 259         struct chnl_net *priv = NULL;
 260         int result = -1;
 261         int llifindex, headroom, tailroom, mtu;
 262         struct net_device *lldev;
 263         ASSERT_RTNL();
 264         priv = netdev_priv(dev);
 265         if (!priv) {
 266                 pr_debug("chnl_net_open: no priv\n");
 267                 return -ENODEV;
 268         }
 269
 270         if (priv->state != CAIF_CONNECTING) {
 271                 priv->state = CAIF_CONNECTING;
 272                 result = caif_connect_client(dev_net(dev), &priv->conn_req,
 273                                                 &priv->chnl, &llifindex,
 274                                                 &headroom, &tailroom);
 275                 if (result != 0) {
 276                                 pr_debug("err: "
 277                                          "Unable to register and open device,"
 278                                          " Err:%d\n",
 279                                          result);
 280                                 goto error;
 281                 }
 282
 283                 lldev = dev_get_by_index(dev_net(dev), llifindex);
 284
 285                 if (lldev == NULL) {
 286                         pr_debug("no interface?\n");
 287                         result = -ENODEV;
 288                         goto error;
 289                 }
 290
 291                 dev->needed_tailroom = tailroom + lldev->needed_tailroom;
 292                 dev->hard_header_len = headroom + lldev->hard_header_len +
 293                         lldev->needed_tailroom;
 294
 295                 /*
 296                  * MTU, head-room etc is not know before we have a
 297                  * CAIF link layer device available. MTU calculation may
 298                  * override initial RTNL configuration.
 299                  * MTU is minimum of current mtu, link layer mtu pluss
 300                  * CAIF head and tail, and PDP GPRS contexts max MTU.
 301                  */
 302                 mtu = min_t(int, dev->mtu, lldev->mtu - (headroom + tailroom));
 303                 mtu = min_t(int, GPRS_PDP_MTU, mtu);
 304                 dev_set_mtu(dev, mtu);
 305                 dev_put(lldev);
 306
 307                 if (mtu < 100) {
 308                         pr_warn("CAIF Interface MTU too small (%d)\n", mtu);
 309                         result = -ENODEV;
 310                         goto error;
 311                 }
 312         }
 313
 314         rtnl_unlock();  /* Release RTNL lock during connect wait */
 315
 316         result = wait_event_interruptible_timeout(priv->netmgmt_wq,
 317                                                 priv->state != CAIF_CONNECTING,
 318                                                 CONNECT_TIMEOUT);
 319
 320         rtnl_lock();
 321
 322         if (result == -ERESTARTSYS) {
 323                 pr_debug("wait_event_interruptible woken by a signal\n");
 324                 result = -ERESTARTSYS;
 325                 goto error;
 326         }
 327
 328         if (result == 0) {
 329                 pr_debug("connect timeout\n");
 330                 caif_disconnect_client(dev_net(dev), &priv->chnl);
 331                 priv->state = CAIF_DISCONNECTED;
 332                 pr_debug("state disconnected\n");
 333                 result = -ETIMEDOUT;
 334                 goto error;
 335         }
 336
 337         if (priv->state != CAIF_CONNECTED) {
 338                 pr_debug("connect failed\n");
 339                 result = -ECONNREFUSED;
 340                 goto error;
 341         }
 342         pr_debug("CAIF Netdevice connected\n");
 343         return 0;
 344
 345 error:
 346         caif_disconnect_client(dev_net(dev), &priv->chnl);
 347         priv->state = CAIF_DISCONNECTED;
 348         pr_debug("state disconnected\n");
 349         return result;
 350
 351 }
 352
 353 static int chnl_net_stop(struct net_device *dev)
 354 {
 355         struct chnl_net *priv;
 356
 357         ASSERT_RTNL();
 358         priv = netdev_priv(dev);
 359         priv->state = CAIF_DISCONNECTED;
 360         caif_disconnect_client(dev_net(dev), &priv->chnl);
 361         return 0;
 362 }
 363
 364 static int chnl_net_init(struct net_device *dev)
 365 {
 366         struct chnl_net *priv;
 367         ASSERT_RTNL();
 368         priv = netdev_priv(dev);
 369         strncpy(priv->name, dev->name, sizeof(priv->name));
 370         return 0;
 371 }
 372
 373 static void chnl_net_uninit(struct net_device *dev)
 374 {
 375         struct chnl_net *priv;
 376         ASSERT_RTNL();
 377         priv = netdev_priv(dev);
 378         robust_list_del(&priv->list_field);
 379 }
 380
 381 static const struct net_device_ops netdev_ops = {
 382         .ndo_open = chnl_net_open,
 383         .ndo_stop = chnl_net_stop,
 384         .ndo_init = chnl_net_init,
 385         .ndo_uninit = chnl_net_uninit,
 386         .ndo_start_xmit = chnl_net_start_xmit,
 387 };
 388
 389 static void chnl_net_destructor(struct net_device *dev)
 390 {
 391         struct chnl_net *priv = netdev_priv(dev);
 392         caif_free_client(&priv->chnl);
 393         free_netdev(dev);
 394 }
 395
 396 static void ipcaif_net_setup(struct net_device *dev)
 397 {
 398         struct chnl_net *priv;
 399         dev->netdev_ops = &netdev_ops;
 400         dev->destructor = chnl_net_destructor;
 401         dev->flags |= IFF_NOARP;
 402         dev->flags |= IFF_POINTOPOINT;
 403         dev->mtu = GPRS_PDP_MTU;
 404         dev->tx_queue_len = CAIF_NET_DEFAULT_QUEUE_LEN;
 405
 406         priv = netdev_priv(dev);
 407         priv->chnl.receive = chnl_recv_cb;
 408         priv->chnl.ctrlcmd = chnl_flowctrl_cb;
 409         priv->netdev = dev;
 410         priv->conn_req.protocol = CAIFPROTO_DATAGRAM;
 411         priv->conn_req.link_selector = CAIF_LINK_HIGH_BANDW;
 412         priv->conn_req.priority = CAIF_PRIO_LOW;
 413         /* Insert illegal value */
 414         priv->conn_req.sockaddr.u.dgm.connection_id = 0;
 415         priv->flowenabled = false;
 416
 417         init_waitqueue_head(&priv->netmgmt_wq);
 418 }
 419
 420
 421 static int ipcaif_fill_info(struct sk_buff *skb, const struct net_device *dev)
 422 {
 423         struct chnl_net *priv;
 424         u8 loop;
 425         priv = netdev_priv(dev);
 426         NLA_PUT_U32(skb, IFLA_CAIF_IPV4_CONNID,
 427                     priv->conn_req.sockaddr.u.dgm.connection_id);
 428         NLA_PUT_U32(skb, IFLA_CAIF_IPV6_CONNID,
 429                     priv->conn_req.sockaddr.u.dgm.connection_id);
 430         loop = priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP;
 431         NLA_PUT_U8(skb, IFLA_CAIF_LOOPBACK, loop);
 432
 433
 434         return 0;
 435 nla_put_failure:
 436         return -EMSGSIZE;
 437
 438 }
 439
 440 static void caif_netlink_parms(struct nlattr *data[],
 441                                 struct caif_connect_request *conn_req)
 442 {
 443         if (!data) {
 444                 pr_warn("no params data found\n");
 445                 return;
 446         }
 447         if (data[IFLA_CAIF_IPV4_CONNID])
 448                 conn_req->sockaddr.u.dgm.connection_id =
 449                         nla_get_u32(data[IFLA_CAIF_IPV4_CONNID]);
 450         if (data[IFLA_CAIF_IPV6_CONNID])
 451                 conn_req->sockaddr.u.dgm.connection_id =
 452                         nla_get_u32(data[IFLA_CAIF_IPV6_CONNID]);
 453         if (data[IFLA_CAIF_LOOPBACK]) {
 454                 if (nla_get_u8(data[IFLA_CAIF_LOOPBACK]))
 455                         conn_req->protocol = CAIFPROTO_DATAGRAM_LOOP;
 456                 else
 457                         conn_req->protocol = CAIFPROTO_DATAGRAM;
 458         }
 459 }
 460
 461 static int ipcaif_newlink(struct net *src_net, struct net_device *dev,
 462                           struct nlattr *tb[], struct nlattr *data[])
 463 {
 464         int ret;
 465         struct chnl_net *caifdev;
 466         ASSERT_RTNL();
 467         caifdev = netdev_priv(dev);
 468         caif_netlink_parms(data, &caifdev->conn_req);
 469         dev_net_set(caifdev->netdev, src_net);
 470
 471         ret = register_netdevice(dev);
 472         if (ret)
 473                 pr_warn("device rtml registration failed\n");
 474         else
 475                 list_add(&caifdev->list_field, &chnl_net_list);
 476
 477         /* Take ifindex as connection-id if null */
 478         if (caifdev->conn_req.sockaddr.u.dgm.connection_id == 0)
 479                 caifdev->conn_req.sockaddr.u.dgm.connection_id = dev->ifindex;
 480         return ret;
 481 }
 482
 483 static int ipcaif_changelink(struct net_device *dev, struct nlattr *tb[],
 484                                 struct nlattr *data[])
 485 {
 486         struct chnl_net *caifdev;
 487         ASSERT_RTNL();
 488         caifdev = netdev_priv(dev);
 489         caif_netlink_parms(data, &caifdev->conn_req);
 490         netdev_state_change(dev);
 491         return 0;
 492 }
 493
 494 static size_t ipcaif_get_size(const struct net_device *dev)
 495 {
 496         return
 497                 /* IFLA_CAIF_IPV4_CONNID */
 498                 nla_total_size(4) +
 499                 /* IFLA_CAIF_IPV6_CONNID */
 500                 nla_total_size(4) +
 501                 /* IFLA_CAIF_LOOPBACK */
 502                 nla_total_size(2) +
 503                 0;
 504 }
 505
 506 static const struct nla_policy ipcaif_policy[IFLA_CAIF_MAX + 1] = {
 507         [IFLA_CAIF_IPV4_CONNID]       = { .type = NLA_U32 },
 508         [IFLA_CAIF_IPV6_CONNID]       = { .type = NLA_U32 },
 509         [IFLA_CAIF_LOOPBACK]          = { .type = NLA_U8 }
 510 };
 511
 512
 513 static struct rtnl_link_ops ipcaif_link_ops __read_mostly = {
 514         .kind           = "caif",
 515         .priv_size      = sizeof(struct chnl_net),
 516         .setup          = ipcaif_net_setup,
 517         .maxtype        = IFLA_CAIF_MAX,
 518         .policy         = ipcaif_policy,
 519         .newlink        = ipcaif_newlink,
 520         .changelink     = ipcaif_changelink,
 521         .get_size       = ipcaif_get_size,
 522         .fill_info      = ipcaif_fill_info,
 523
 524 };
 525
 526 static int __init chnl_init_module(void)
 527 {
 528         return rtnl_link_register(&ipcaif_link_ops);
 529 }
 530
 531 static void __exit chnl_exit_module(void)
 532 {
 533         struct chnl_net *dev = NULL;
 534         struct list_head *list_node;
 535         struct list_head *_tmp;
 536         rtnl_link_unregister(&ipcaif_link_ops);
 537         rtnl_lock();
 538         list_for_each_safe(list_node, _tmp, &chnl_net_list) {
 539                 dev = list_entry(list_node, struct chnl_net, list_field);
 540                 list_del(list_node);
 541                 delete_device(dev);
 542         }
 543         rtnl_unlock();
 544 }
 545
 546 module_init(chnl_init_module);
 547 module_exit(chnl_exit_module);