net/caif/chnl_net.c

   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. */
  32 static LIST_HEAD(chnl_net_list);
  33
  34 MODULE_LICENSE("GPL");
  35 MODULE_ALIAS_RTNL_LINK("caif");
  36
  37 enum caif_states {
  38         CAIF_CONNECTED          = 1,
  39         CAIF_CONNECTING,
  40         CAIF_DISCONNECTED,
  41         CAIF_SHUTDOWN
  42 };
  43
  44 struct 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
  56 static 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
  70 static 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
 125 static 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
 133 static 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 }
 147 static DECLARE_WORK(close_worker, close_work);
 148
 149 static 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
 155 static 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
 161 static 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
 209 static 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
 255 static 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
 342 error:
 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
 350 static 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
 361 static 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
 370 static 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
 378 static 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
 386 static 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
 392 static 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
 418 static 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;
 432 nla_put_failure:
 433         return -EMSGSIZE;
 434
 435 }
 436
 437 static 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
 458 static 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
 482 static 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
 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);