linux/net/caif/chnl_net.c
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   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/*This list is protected by the rtnl lock. */
  34static LIST_HEAD(chnl_net_list);
  35
  36MODULE_LICENSE("GPL");
  37MODULE_ALIAS_RTNL_LINK("caif");
  38
  39enum caif_states {
  40        CAIF_CONNECTED          = 1,
  41        CAIF_CONNECTING,
  42        CAIF_DISCONNECTED,
  43        CAIF_SHUTDOWN
  44};
  45
  46struct 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
  59static 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
  73static int chnl_recv_cb(struct cflayer *layr, struct cfpkt *pkt)
  74{
  75        struct sk_buff *skb;
  76        struct chnl_net *priv  = container_of(layr, struct chnl_net, chnl);
  77        int pktlen;
  78        int err = 0;
  79
  80        priv = container_of(layr, struct chnl_net, chnl);
  81
  82        if (!priv)
  83                return -EINVAL;
  84
  85        /* Get length of CAIF packet. */
  86        pktlen = cfpkt_getlen(pkt);
  87
  88        skb = (struct sk_buff *) cfpkt_tonative(pkt);
  89        /* Pass some minimum information and
  90         * send the packet to the net stack.
  91         */
  92        skb->dev = priv->netdev;
  93        skb->protocol = htons(ETH_P_IP);
  94
  95        /* If we change the header in loop mode, the checksum is corrupted. */
  96        if (priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP)
  97                skb->ip_summed = CHECKSUM_UNNECESSARY;
  98        else
  99                skb->ip_summed = CHECKSUM_NONE;
 100
 101        if (in_interrupt())
 102                netif_rx(skb);
 103        else
 104                netif_rx_ni(skb);
 105
 106        /* Update statistics. */
 107        priv->netdev->stats.rx_packets++;
 108        priv->netdev->stats.rx_bytes += pktlen;
 109
 110        return err;
 111}
 112
 113static int delete_device(struct chnl_net *dev)
 114{
 115        ASSERT_RTNL();
 116        if (dev->netdev)
 117                unregister_netdevice(dev->netdev);
 118        return 0;
 119}
 120
 121static void close_work(struct work_struct *work)
 122{
 123        struct chnl_net *dev = NULL;
 124        struct list_head *list_node;
 125        struct list_head *_tmp;
 126        /* May be called with or without RTNL lock held */
 127        int islocked = rtnl_is_locked();
 128        if (!islocked)
 129                rtnl_lock();
 130        list_for_each_safe(list_node, _tmp, &chnl_net_list) {
 131                dev = list_entry(list_node, struct chnl_net, list_field);
 132                if (dev->state == CAIF_SHUTDOWN)
 133                        dev_close(dev->netdev);
 134        }
 135        if (!islocked)
 136                rtnl_unlock();
 137}
 138static DECLARE_WORK(close_worker, close_work);
 139
 140static void chnl_flowctrl_cb(struct cflayer *layr, enum caif_ctrlcmd flow,
 141                                int phyid)
 142{
 143        struct chnl_net *priv = container_of(layr, struct chnl_net, chnl);
 144        pr_debug("NET flowctrl func called flow: %s\n",
 145                flow == CAIF_CTRLCMD_FLOW_ON_IND ? "ON" :
 146                flow == CAIF_CTRLCMD_INIT_RSP ? "INIT" :
 147                flow == CAIF_CTRLCMD_FLOW_OFF_IND ? "OFF" :
 148                flow == CAIF_CTRLCMD_DEINIT_RSP ? "CLOSE/DEINIT" :
 149                flow == CAIF_CTRLCMD_INIT_FAIL_RSP ? "OPEN_FAIL" :
 150                flow == CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND ?
 151                 "REMOTE_SHUTDOWN" : "UKNOWN CTRL COMMAND");
 152
 153
 154
 155        switch (flow) {
 156        case CAIF_CTRLCMD_FLOW_OFF_IND:
 157                priv->flowenabled = false;
 158                netif_stop_queue(priv->netdev);
 159                break;
 160        case CAIF_CTRLCMD_DEINIT_RSP:
 161                priv->state = CAIF_DISCONNECTED;
 162                break;
 163        case CAIF_CTRLCMD_INIT_FAIL_RSP:
 164                priv->state = CAIF_DISCONNECTED;
 165                wake_up_interruptible(&priv->netmgmt_wq);
 166                break;
 167        case CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND:
 168                priv->state = CAIF_SHUTDOWN;
 169                netif_tx_disable(priv->netdev);
 170                schedule_work(&close_worker);
 171                break;
 172        case CAIF_CTRLCMD_FLOW_ON_IND:
 173                priv->flowenabled = true;
 174                netif_wake_queue(priv->netdev);
 175                break;
 176        case CAIF_CTRLCMD_INIT_RSP:
 177                priv->state = CAIF_CONNECTED;
 178                priv->flowenabled = true;
 179                netif_wake_queue(priv->netdev);
 180                wake_up_interruptible(&priv->netmgmt_wq);
 181                break;
 182        default:
 183                break;
 184        }
 185}
 186
 187static int chnl_net_start_xmit(struct sk_buff *skb, struct net_device *dev)
 188{
 189        struct chnl_net *priv;
 190        struct cfpkt *pkt = NULL;
 191        int len;
 192        int result = -1;
 193        /* Get our private data. */
 194        priv = netdev_priv(dev);
 195
 196        if (skb->len > priv->netdev->mtu) {
 197                pr_warn("Size of skb exceeded MTU\n");
 198                return -ENOSPC;
 199        }
 200
 201        if (!priv->flowenabled) {
 202                pr_debug("dropping packets flow off\n");
 203                return NETDEV_TX_BUSY;
 204        }
 205
 206        if (priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP)
 207                swap(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr);
 208
 209        /* Store original SKB length. */
 210        len = skb->len;
 211
 212        pkt = cfpkt_fromnative(CAIF_DIR_OUT, (void *) skb);
 213
 214        /* Send the packet down the stack. */
 215        result = priv->chnl.dn->transmit(priv->chnl.dn, pkt);
 216        if (result) {
 217                if (result == -EAGAIN)
 218                        result = NETDEV_TX_BUSY;
 219                return result;
 220        }
 221
 222        /* Update statistics. */
 223        dev->stats.tx_packets++;
 224        dev->stats.tx_bytes += len;
 225
 226        return NETDEV_TX_OK;
 227}
 228
 229static int chnl_net_open(struct net_device *dev)
 230{
 231        struct chnl_net *priv = NULL;
 232        int result = -1;
 233        int llifindex, headroom, tailroom, mtu;
 234        struct net_device *lldev;
 235        ASSERT_RTNL();
 236        priv = netdev_priv(dev);
 237        if (!priv) {
 238                pr_debug("chnl_net_open: no priv\n");
 239                return -ENODEV;
 240        }
 241
 242        if (priv->state != CAIF_CONNECTING) {
 243                priv->state = CAIF_CONNECTING;
 244                result = caif_connect_client(&priv->conn_req, &priv->chnl,
 245                                        &llifindex, &headroom, &tailroom);
 246                if (result != 0) {
 247                                pr_debug("err: "
 248                                         "Unable to register and open device,"
 249                                         " Err:%d\n",
 250                                         result);
 251                                goto error;
 252                }
 253
 254                lldev = dev_get_by_index(dev_net(dev), llifindex);
 255
 256                if (lldev == NULL) {
 257                        pr_debug("no interface?\n");
 258                        result = -ENODEV;
 259                        goto error;
 260                }
 261
 262                dev->needed_tailroom = tailroom + lldev->needed_tailroom;
 263                dev->hard_header_len = headroom + lldev->hard_header_len +
 264                        lldev->needed_tailroom;
 265
 266                /*
 267                 * MTU, head-room etc is not know before we have a
 268                 * CAIF link layer device available. MTU calculation may
 269                 * override initial RTNL configuration.
 270                 * MTU is minimum of current mtu, link layer mtu pluss
 271                 * CAIF head and tail, and PDP GPRS contexts max MTU.
 272                 */
 273                mtu = min_t(int, dev->mtu, lldev->mtu - (headroom + tailroom));
 274                mtu = min_t(int, GPRS_PDP_MTU, mtu);
 275                dev_set_mtu(dev, mtu);
 276                dev_put(lldev);
 277
 278                if (mtu < 100) {
 279                        pr_warn("CAIF Interface MTU too small (%d)\n", mtu);
 280                        result = -ENODEV;
 281                        goto error;
 282                }
 283        }
 284
 285        rtnl_unlock();  /* Release RTNL lock during connect wait */
 286
 287        result = wait_event_interruptible_timeout(priv->netmgmt_wq,
 288                                                priv->state != CAIF_CONNECTING,
 289                                                CONNECT_TIMEOUT);
 290
 291        rtnl_lock();
 292
 293        if (result == -ERESTARTSYS) {
 294                pr_debug("wait_event_interruptible woken by a signal\n");
 295                result = -ERESTARTSYS;
 296                goto error;
 297        }
 298
 299        if (result == 0) {
 300                pr_debug("connect timeout\n");
 301                caif_disconnect_client(&priv->chnl);
 302                priv->state = CAIF_DISCONNECTED;
 303                pr_debug("state disconnected\n");
 304                result = -ETIMEDOUT;
 305                goto error;
 306        }
 307
 308        if (priv->state != CAIF_CONNECTED) {
 309                pr_debug("connect failed\n");
 310                result = -ECONNREFUSED;
 311                goto error;
 312        }
 313        pr_debug("CAIF Netdevice connected\n");
 314        return 0;
 315
 316error:
 317        caif_disconnect_client(&priv->chnl);
 318        priv->state = CAIF_DISCONNECTED;
 319        pr_debug("state disconnected\n");
 320        return result;
 321
 322}
 323
 324static int chnl_net_stop(struct net_device *dev)
 325{
 326        struct chnl_net *priv;
 327
 328        ASSERT_RTNL();
 329        priv = netdev_priv(dev);
 330        priv->state = CAIF_DISCONNECTED;
 331        caif_disconnect_client(&priv->chnl);
 332        return 0;
 333}
 334
 335static int chnl_net_init(struct net_device *dev)
 336{
 337        struct chnl_net *priv;
 338        ASSERT_RTNL();
 339        priv = netdev_priv(dev);
 340        strncpy(priv->name, dev->name, sizeof(priv->name));
 341        return 0;
 342}
 343
 344static void chnl_net_uninit(struct net_device *dev)
 345{
 346        struct chnl_net *priv;
 347        ASSERT_RTNL();
 348        priv = netdev_priv(dev);
 349        robust_list_del(&priv->list_field);
 350}
 351
 352static const struct net_device_ops netdev_ops = {
 353        .ndo_open = chnl_net_open,
 354        .ndo_stop = chnl_net_stop,
 355        .ndo_init = chnl_net_init,
 356        .ndo_uninit = chnl_net_uninit,
 357        .ndo_start_xmit = chnl_net_start_xmit,
 358};
 359
 360static void ipcaif_net_setup(struct net_device *dev)
 361{
 362        struct chnl_net *priv;
 363        dev->netdev_ops = &netdev_ops;
 364        dev->destructor = free_netdev;
 365        dev->flags |= IFF_NOARP;
 366        dev->flags |= IFF_POINTOPOINT;
 367        dev->mtu = GPRS_PDP_MTU;
 368        dev->tx_queue_len = CAIF_NET_DEFAULT_QUEUE_LEN;
 369
 370        priv = netdev_priv(dev);
 371        priv->chnl.receive = chnl_recv_cb;
 372        priv->chnl.ctrlcmd = chnl_flowctrl_cb;
 373        priv->netdev = dev;
 374        priv->conn_req.protocol = CAIFPROTO_DATAGRAM;
 375        priv->conn_req.link_selector = CAIF_LINK_HIGH_BANDW;
 376        priv->conn_req.priority = CAIF_PRIO_LOW;
 377        /* Insert illegal value */
 378        priv->conn_req.sockaddr.u.dgm.connection_id = -1;
 379        priv->flowenabled = false;
 380
 381        ASSERT_RTNL();
 382        init_waitqueue_head(&priv->netmgmt_wq);
 383        list_add(&priv->list_field, &chnl_net_list);
 384}
 385
 386
 387static int ipcaif_fill_info(struct sk_buff *skb, const struct net_device *dev)
 388{
 389        struct chnl_net *priv;
 390        u8 loop;
 391        priv = netdev_priv(dev);
 392        NLA_PUT_U32(skb, IFLA_CAIF_IPV4_CONNID,
 393                    priv->conn_req.sockaddr.u.dgm.connection_id);
 394        NLA_PUT_U32(skb, IFLA_CAIF_IPV6_CONNID,
 395                    priv->conn_req.sockaddr.u.dgm.connection_id);
 396        loop = priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP;
 397        NLA_PUT_U8(skb, IFLA_CAIF_LOOPBACK, loop);
 398
 399
 400        return 0;
 401nla_put_failure:
 402        return -EMSGSIZE;
 403
 404}
 405
 406static void caif_netlink_parms(struct nlattr *data[],
 407                                struct caif_connect_request *conn_req)
 408{
 409        if (!data) {
 410                pr_warn("no params data found\n");
 411                return;
 412        }
 413        if (data[IFLA_CAIF_IPV4_CONNID])
 414                conn_req->sockaddr.u.dgm.connection_id =
 415                        nla_get_u32(data[IFLA_CAIF_IPV4_CONNID]);
 416        if (data[IFLA_CAIF_IPV6_CONNID])
 417                conn_req->sockaddr.u.dgm.connection_id =
 418                        nla_get_u32(data[IFLA_CAIF_IPV6_CONNID]);
 419        if (data[IFLA_CAIF_LOOPBACK]) {
 420                if (nla_get_u8(data[IFLA_CAIF_LOOPBACK]))
 421                        conn_req->protocol = CAIFPROTO_DATAGRAM_LOOP;
 422                else
 423                        conn_req->protocol = CAIFPROTO_DATAGRAM;
 424        }
 425}
 426
 427static int ipcaif_newlink(struct net *src_net, struct net_device *dev,
 428                          struct nlattr *tb[], struct nlattr *data[])
 429{
 430        int ret;
 431        struct chnl_net *caifdev;
 432        ASSERT_RTNL();
 433        caifdev = netdev_priv(dev);
 434        caif_netlink_parms(data, &caifdev->conn_req);
 435        dev_net_set(caifdev->netdev, src_net);
 436
 437        ret = register_netdevice(dev);
 438        if (ret)
 439                pr_warn("device rtml registration failed\n");
 440        return ret;
 441}
 442
 443static int ipcaif_changelink(struct net_device *dev, struct nlattr *tb[],
 444                                struct nlattr *data[])
 445{
 446        struct chnl_net *caifdev;
 447        ASSERT_RTNL();
 448        caifdev = netdev_priv(dev);
 449        caif_netlink_parms(data, &caifdev->conn_req);
 450        netdev_state_change(dev);
 451        return 0;
 452}
 453
 454static size_t ipcaif_get_size(const struct net_device *dev)
 455{
 456        return
 457                /* IFLA_CAIF_IPV4_CONNID */
 458                nla_total_size(4) +
 459                /* IFLA_CAIF_IPV6_CONNID */
 460                nla_total_size(4) +
 461                /* IFLA_CAIF_LOOPBACK */
 462                nla_total_size(2) +
 463                0;
 464}
 465
 466static const struct nla_policy ipcaif_policy[IFLA_CAIF_MAX + 1] = {
 467        [IFLA_CAIF_IPV4_CONNID]       = { .type = NLA_U32 },
 468        [IFLA_CAIF_IPV6_CONNID]       = { .type = NLA_U32 },
 469        [IFLA_CAIF_LOOPBACK]          = { .type = NLA_U8 }
 470};
 471
 472
 473static struct rtnl_link_ops ipcaif_link_ops __read_mostly = {
 474        .kind           = "caif",
 475        .priv_size      = sizeof(struct chnl_net),
 476        .setup          = ipcaif_net_setup,
 477        .maxtype        = IFLA_CAIF_MAX,
 478        .policy         = ipcaif_policy,
 479        .newlink        = ipcaif_newlink,
 480        .changelink     = ipcaif_changelink,
 481        .get_size       = ipcaif_get_size,
 482        .fill_info      = ipcaif_fill_info,
 483
 484};
 485
 486static int __init chnl_init_module(void)
 487{
 488        return rtnl_link_register(&ipcaif_link_ops);
 489}
 490
 491static void __exit chnl_exit_module(void)
 492{
 493        struct chnl_net *dev = NULL;
 494        struct list_head *list_node;
 495        struct list_head *_tmp;
 496        rtnl_link_unregister(&ipcaif_link_ops);
 497        rtnl_lock();
 498        list_for_each_safe(list_node, _tmp, &chnl_net_list) {
 499                dev = list_entry(list_node, struct chnl_net, list_field);
 500                list_del(list_node);
 501                delete_device(dev);
 502        }
 503        rtnl_unlock();
 504}
 505
 506module_init(chnl_init_module);
 507module_exit(chnl_exit_module);
 508