linux/net/caif/chnl_net.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Copyright (C) ST-Ericsson AB 2010
   4 * Authors:     Sjur Brendeland
   5 *              Daniel Martensson
   6 */
   7
   8#define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
   9
  10#include <linux/fs.h>
  11#include <linux/init.h>
  12#include <linux/module.h>
  13#include <linux/netdevice.h>
  14#include <linux/if_ether.h>
  15#include <linux/ip.h>
  16#include <linux/sched.h>
  17#include <linux/sockios.h>
  18#include <linux/caif/if_caif.h>
  19#include <net/rtnetlink.h>
  20#include <net/caif/caif_layer.h>
  21#include <net/caif/cfpkt.h>
  22#include <net/caif/caif_dev.h>
  23
  24/* GPRS PDP connection has MTU to 1500 */
  25#define GPRS_PDP_MTU 1500
  26/* 5 sec. connect timeout */
  27#define CONNECT_TIMEOUT (5 * HZ)
  28#define CAIF_NET_DEFAULT_QUEUE_LEN 500
  29#define UNDEF_CONNID 0xffffffff
  30
  31/*This list is protected by the rtnl lock. */
  32static LIST_HEAD(chnl_net_list);
  33
  34MODULE_LICENSE("GPL");
  35MODULE_ALIAS_RTNL_LINK("caif");
  36
  37enum caif_states {
  38        CAIF_CONNECTED          = 1,
  39        CAIF_CONNECTING,
  40        CAIF_DISCONNECTED,
  41        CAIF_SHUTDOWN
  42};
  43
  44struct chnl_net {
  45        struct cflayer chnl;
  46        struct caif_connect_request conn_req;
  47        struct list_head list_field;
  48        struct net_device *netdev;
  49        char name[256];
  50        wait_queue_head_t netmgmt_wq;
  51        /* Flow status to remember and control the transmission. */
  52        bool flowenabled;
  53        enum caif_states state;
  54};
  55
  56static void robust_list_del(struct list_head *delete_node)
  57{
  58        struct list_head *list_node;
  59        struct list_head *n;
  60        ASSERT_RTNL();
  61        list_for_each_safe(list_node, n, &chnl_net_list) {
  62                if (list_node == delete_node) {
  63                        list_del(list_node);
  64                        return;
  65                }
  66        }
  67        WARN_ON(1);
  68}
  69
  70static int chnl_recv_cb(struct cflayer *layr, struct cfpkt *pkt)
  71{
  72        struct sk_buff *skb;
  73        struct chnl_net *priv;
  74        int pktlen;
  75        const u8 *ip_version;
  76        u8 buf;
  77
  78        priv = container_of(layr, struct chnl_net, chnl);
  79
  80        skb = (struct sk_buff *) cfpkt_tonative(pkt);
  81
  82        /* Get length of CAIF packet. */
  83        pktlen = skb->len;
  84
  85        /* Pass some minimum information and
  86         * send the packet to the net stack.
  87         */
  88        skb->dev = priv->netdev;
  89
  90        /* check the version of IP */
  91        ip_version = skb_header_pointer(skb, 0, 1, &buf);
  92        if (!ip_version) {
  93                kfree_skb(skb);
  94                return -EINVAL;
  95        }
  96
  97        switch (*ip_version >> 4) {
  98        case 4:
  99                skb->protocol = htons(ETH_P_IP);
 100                break;
 101        case 6:
 102                skb->protocol = htons(ETH_P_IPV6);
 103                break;
 104        default:
 105                kfree_skb(skb);
 106                priv->netdev->stats.rx_errors++;
 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        netif_rx_any_context(skb);
 117
 118        /* Update statistics. */
 119        priv->netdev->stats.rx_packets++;
 120        priv->netdev->stats.rx_bytes += pktlen;
 121
 122        return 0;
 123}
 124
 125static int delete_device(struct chnl_net *dev)
 126{
 127        ASSERT_RTNL();
 128        if (dev->netdev)
 129                unregister_netdevice(dev->netdev);
 130        return 0;
 131}
 132
 133static void close_work(struct work_struct *work)
 134{
 135        struct chnl_net *dev = NULL;
 136        struct list_head *list_node;
 137        struct list_head *_tmp;
 138
 139        rtnl_lock();
 140        list_for_each_safe(list_node, _tmp, &chnl_net_list) {
 141                dev = list_entry(list_node, struct chnl_net, list_field);
 142                if (dev->state == CAIF_SHUTDOWN)
 143                        dev_close(dev->netdev);
 144        }
 145        rtnl_unlock();
 146}
 147static DECLARE_WORK(close_worker, close_work);
 148
 149static void chnl_hold(struct cflayer *lyr)
 150{
 151        struct chnl_net *priv = container_of(lyr, struct chnl_net, chnl);
 152        dev_hold(priv->netdev);
 153}
 154
 155static void chnl_put(struct cflayer *lyr)
 156{
 157        struct chnl_net *priv = container_of(lyr, struct chnl_net, chnl);
 158        dev_put(priv->netdev);
 159}
 160
 161static void chnl_flowctrl_cb(struct cflayer *layr, enum caif_ctrlcmd flow,
 162                             int phyid)
 163{
 164        struct chnl_net *priv = container_of(layr, struct chnl_net, chnl);
 165        pr_debug("NET flowctrl func called flow: %s\n",
 166                flow == CAIF_CTRLCMD_FLOW_ON_IND ? "ON" :
 167                flow == CAIF_CTRLCMD_INIT_RSP ? "INIT" :
 168                flow == CAIF_CTRLCMD_FLOW_OFF_IND ? "OFF" :
 169                flow == CAIF_CTRLCMD_DEINIT_RSP ? "CLOSE/DEINIT" :
 170                flow == CAIF_CTRLCMD_INIT_FAIL_RSP ? "OPEN_FAIL" :
 171                flow == CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND ?
 172                 "REMOTE_SHUTDOWN" : "UNKNOWN CTRL COMMAND");
 173
 174
 175
 176        switch (flow) {
 177        case CAIF_CTRLCMD_FLOW_OFF_IND:
 178                priv->flowenabled = false;
 179                netif_stop_queue(priv->netdev);
 180                break;
 181        case CAIF_CTRLCMD_DEINIT_RSP:
 182                priv->state = CAIF_DISCONNECTED;
 183                break;
 184        case CAIF_CTRLCMD_INIT_FAIL_RSP:
 185                priv->state = CAIF_DISCONNECTED;
 186                wake_up_interruptible(&priv->netmgmt_wq);
 187                break;
 188        case CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND:
 189                priv->state = CAIF_SHUTDOWN;
 190                netif_tx_disable(priv->netdev);
 191                schedule_work(&close_worker);
 192                break;
 193        case CAIF_CTRLCMD_FLOW_ON_IND:
 194                priv->flowenabled = true;
 195                netif_wake_queue(priv->netdev);
 196                break;
 197        case CAIF_CTRLCMD_INIT_RSP:
 198                caif_client_register_refcnt(&priv->chnl, chnl_hold, chnl_put);
 199                priv->state = CAIF_CONNECTED;
 200                priv->flowenabled = true;
 201                netif_wake_queue(priv->netdev);
 202                wake_up_interruptible(&priv->netmgmt_wq);
 203                break;
 204        default:
 205                break;
 206        }
 207}
 208
 209static netdev_tx_t chnl_net_start_xmit(struct sk_buff *skb,
 210                                       struct net_device *dev)
 211{
 212        struct chnl_net *priv;
 213        struct cfpkt *pkt = NULL;
 214        int len;
 215        int result = -1;
 216        /* Get our private data. */
 217        priv = netdev_priv(dev);
 218
 219        if (skb->len > priv->netdev->mtu) {
 220                pr_warn("Size of skb exceeded MTU\n");
 221                kfree_skb(skb);
 222                dev->stats.tx_errors++;
 223                return NETDEV_TX_OK;
 224        }
 225
 226        if (!priv->flowenabled) {
 227                pr_debug("dropping packets flow off\n");
 228                kfree_skb(skb);
 229                dev->stats.tx_dropped++;
 230                return NETDEV_TX_OK;
 231        }
 232
 233        if (priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP)
 234                swap(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr);
 235
 236        /* Store original SKB length. */
 237        len = skb->len;
 238
 239        pkt = cfpkt_fromnative(CAIF_DIR_OUT, (void *) skb);
 240
 241        /* Send the packet down the stack. */
 242        result = priv->chnl.dn->transmit(priv->chnl.dn, pkt);
 243        if (result) {
 244                dev->stats.tx_dropped++;
 245                return NETDEV_TX_OK;
 246        }
 247
 248        /* Update statistics. */
 249        dev->stats.tx_packets++;
 250        dev->stats.tx_bytes += len;
 251
 252        return NETDEV_TX_OK;
 253}
 254
 255static int chnl_net_open(struct net_device *dev)
 256{
 257        struct chnl_net *priv = NULL;
 258        int result = -1;
 259        int llifindex, headroom, tailroom, mtu;
 260        struct net_device *lldev;
 261        ASSERT_RTNL();
 262        priv = netdev_priv(dev);
 263        if (!priv) {
 264                pr_debug("chnl_net_open: no priv\n");
 265                return -ENODEV;
 266        }
 267
 268        if (priv->state != CAIF_CONNECTING) {
 269                priv->state = CAIF_CONNECTING;
 270                result = caif_connect_client(dev_net(dev), &priv->conn_req,
 271                                                &priv->chnl, &llifindex,
 272                                                &headroom, &tailroom);
 273                if (result != 0) {
 274                                pr_debug("err: "
 275                                         "Unable to register and open device,"
 276                                         " Err:%d\n",
 277                                         result);
 278                                goto error;
 279                }
 280
 281                lldev = __dev_get_by_index(dev_net(dev), llifindex);
 282
 283                if (lldev == NULL) {
 284                        pr_debug("no interface?\n");
 285                        result = -ENODEV;
 286                        goto error;
 287                }
 288
 289                dev->needed_tailroom = tailroom + lldev->needed_tailroom;
 290                dev->hard_header_len = headroom + lldev->hard_header_len +
 291                        lldev->needed_tailroom;
 292
 293                /*
 294                 * MTU, head-room etc is not know before we have a
 295                 * CAIF link layer device available. MTU calculation may
 296                 * override initial RTNL configuration.
 297                 * MTU is minimum of current mtu, link layer mtu pluss
 298                 * CAIF head and tail, and PDP GPRS contexts max MTU.
 299                 */
 300                mtu = min_t(int, dev->mtu, lldev->mtu - (headroom + tailroom));
 301                mtu = min_t(int, GPRS_PDP_MTU, mtu);
 302                dev_set_mtu(dev, mtu);
 303
 304                if (mtu < 100) {
 305                        pr_warn("CAIF Interface MTU too small (%d)\n", mtu);
 306                        result = -ENODEV;
 307                        goto error;
 308                }
 309        }
 310
 311        rtnl_unlock();  /* Release RTNL lock during connect wait */
 312
 313        result = wait_event_interruptible_timeout(priv->netmgmt_wq,
 314                                                priv->state != CAIF_CONNECTING,
 315                                                CONNECT_TIMEOUT);
 316
 317        rtnl_lock();
 318
 319        if (result == -ERESTARTSYS) {
 320                pr_debug("wait_event_interruptible woken by a signal\n");
 321                result = -ERESTARTSYS;
 322                goto error;
 323        }
 324
 325        if (result == 0) {
 326                pr_debug("connect timeout\n");
 327                caif_disconnect_client(dev_net(dev), &priv->chnl);
 328                priv->state = CAIF_DISCONNECTED;
 329                pr_debug("state disconnected\n");
 330                result = -ETIMEDOUT;
 331                goto error;
 332        }
 333
 334        if (priv->state != CAIF_CONNECTED) {
 335                pr_debug("connect failed\n");
 336                result = -ECONNREFUSED;
 337                goto error;
 338        }
 339        pr_debug("CAIF Netdevice connected\n");
 340        return 0;
 341
 342error:
 343        caif_disconnect_client(dev_net(dev), &priv->chnl);
 344        priv->state = CAIF_DISCONNECTED;
 345        pr_debug("state disconnected\n");
 346        return result;
 347
 348}
 349
 350static int chnl_net_stop(struct net_device *dev)
 351{
 352        struct chnl_net *priv;
 353
 354        ASSERT_RTNL();
 355        priv = netdev_priv(dev);
 356        priv->state = CAIF_DISCONNECTED;
 357        caif_disconnect_client(dev_net(dev), &priv->chnl);
 358        return 0;
 359}
 360
 361static int chnl_net_init(struct net_device *dev)
 362{
 363        struct chnl_net *priv;
 364        ASSERT_RTNL();
 365        priv = netdev_priv(dev);
 366        strncpy(priv->name, dev->name, sizeof(priv->name));
 367        return 0;
 368}
 369
 370static void chnl_net_uninit(struct net_device *dev)
 371{
 372        struct chnl_net *priv;
 373        ASSERT_RTNL();
 374        priv = netdev_priv(dev);
 375        robust_list_del(&priv->list_field);
 376}
 377
 378static const struct net_device_ops netdev_ops = {
 379        .ndo_open = chnl_net_open,
 380        .ndo_stop = chnl_net_stop,
 381        .ndo_init = chnl_net_init,
 382        .ndo_uninit = chnl_net_uninit,
 383        .ndo_start_xmit = chnl_net_start_xmit,
 384};
 385
 386static void chnl_net_destructor(struct net_device *dev)
 387{
 388        struct chnl_net *priv = netdev_priv(dev);
 389        caif_free_client(&priv->chnl);
 390}
 391
 392static void ipcaif_net_setup(struct net_device *dev)
 393{
 394        struct chnl_net *priv;
 395        dev->netdev_ops = &netdev_ops;
 396        dev->needs_free_netdev = true;
 397        dev->priv_destructor = chnl_net_destructor;
 398        dev->flags |= IFF_NOARP;
 399        dev->flags |= IFF_POINTOPOINT;
 400        dev->mtu = GPRS_PDP_MTU;
 401        dev->tx_queue_len = CAIF_NET_DEFAULT_QUEUE_LEN;
 402
 403        priv = netdev_priv(dev);
 404        priv->chnl.receive = chnl_recv_cb;
 405        priv->chnl.ctrlcmd = chnl_flowctrl_cb;
 406        priv->netdev = dev;
 407        priv->conn_req.protocol = CAIFPROTO_DATAGRAM;
 408        priv->conn_req.link_selector = CAIF_LINK_HIGH_BANDW;
 409        priv->conn_req.priority = CAIF_PRIO_LOW;
 410        /* Insert illegal value */
 411        priv->conn_req.sockaddr.u.dgm.connection_id = UNDEF_CONNID;
 412        priv->flowenabled = false;
 413
 414        init_waitqueue_head(&priv->netmgmt_wq);
 415}
 416
 417
 418static int ipcaif_fill_info(struct sk_buff *skb, const struct net_device *dev)
 419{
 420        struct chnl_net *priv;
 421        u8 loop;
 422        priv = netdev_priv(dev);
 423        if (nla_put_u32(skb, IFLA_CAIF_IPV4_CONNID,
 424                        priv->conn_req.sockaddr.u.dgm.connection_id) ||
 425            nla_put_u32(skb, IFLA_CAIF_IPV6_CONNID,
 426                        priv->conn_req.sockaddr.u.dgm.connection_id))
 427                goto nla_put_failure;
 428        loop = priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP;
 429        if (nla_put_u8(skb, IFLA_CAIF_LOOPBACK, loop))
 430                goto nla_put_failure;
 431        return 0;
 432nla_put_failure:
 433        return -EMSGSIZE;
 434
 435}
 436
 437static void caif_netlink_parms(struct nlattr *data[],
 438                               struct caif_connect_request *conn_req)
 439{
 440        if (!data) {
 441                pr_warn("no params data found\n");
 442                return;
 443        }
 444        if (data[IFLA_CAIF_IPV4_CONNID])
 445                conn_req->sockaddr.u.dgm.connection_id =
 446                        nla_get_u32(data[IFLA_CAIF_IPV4_CONNID]);
 447        if (data[IFLA_CAIF_IPV6_CONNID])
 448                conn_req->sockaddr.u.dgm.connection_id =
 449                        nla_get_u32(data[IFLA_CAIF_IPV6_CONNID]);
 450        if (data[IFLA_CAIF_LOOPBACK]) {
 451                if (nla_get_u8(data[IFLA_CAIF_LOOPBACK]))
 452                        conn_req->protocol = CAIFPROTO_DATAGRAM_LOOP;
 453                else
 454                        conn_req->protocol = CAIFPROTO_DATAGRAM;
 455        }
 456}
 457
 458static int ipcaif_newlink(struct net *src_net, struct net_device *dev,
 459                          struct nlattr *tb[], struct nlattr *data[],
 460                          struct netlink_ext_ack *extack)
 461{
 462        int ret;
 463        struct chnl_net *caifdev;
 464        ASSERT_RTNL();
 465        caifdev = netdev_priv(dev);
 466        caif_netlink_parms(data, &caifdev->conn_req);
 467
 468        ret = register_netdevice(dev);
 469        if (ret)
 470                pr_warn("device rtml registration failed\n");
 471        else
 472                list_add(&caifdev->list_field, &chnl_net_list);
 473
 474        /* Use ifindex as connection id, and use loopback channel default. */
 475        if (caifdev->conn_req.sockaddr.u.dgm.connection_id == UNDEF_CONNID) {
 476                caifdev->conn_req.sockaddr.u.dgm.connection_id = dev->ifindex;
 477                caifdev->conn_req.protocol = CAIFPROTO_DATAGRAM_LOOP;
 478        }
 479        return ret;
 480}
 481
 482static int ipcaif_changelink(struct net_device *dev, struct nlattr *tb[],
 483                             struct nlattr *data[],
 484                             struct netlink_ext_ack *extack)
 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
 494static 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
 506static 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
 513static 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
 526static int __init chnl_init_module(void)
 527{
 528        return rtnl_link_register(&ipcaif_link_ops);
 529}
 530
 531static 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
 546module_init(chnl_init_module);
 547module_exit(chnl_exit_module);
 548