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/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. */
  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;
  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
 133static 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
 141static 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}
 155static DECLARE_WORK(close_worker, close_work);
 156
 157static 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
 163static 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
 169static 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
 217static 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
 262static 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
 350error:
 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
 358static 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
 369static 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
 378static 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
 386static 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
 394static 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
 401static 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
 426static 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;
 440nla_put_failure:
 441        return -EMSGSIZE;
 442
 443}
 444
 445static 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
 466static 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
 490static 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
 501static 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
 513static 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
 520static 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
 533static int __init chnl_init_module(void)
 534{
 535        return rtnl_link_register(&ipcaif_link_ops);
 536}
 537
 538static 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
 553module_init(chnl_init_module);
 554module_exit(chnl_exit_module);
 555
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