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         if (!priv)
  80                 return -EINVAL;
  81
  82         skb = (struct sk_buff *) cfpkt_tonative(pkt);
  83
  84         /* Get length of CAIF packet. */
  85         pktlen = skb->len;
  86
  87         /* Pass some minimum information and
  88          * send the packet to the net stack.
  89          */
  90         skb->dev = priv->netdev;
  91
  92         /* check the version of IP */
  93         ip_version = skb_header_pointer(skb, 0, 1, &buf);
  94         if (!ip_version) {
  95                 kfree_skb(skb);
  96                 return -EINVAL;
  97         }
  98
  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                 kfree_skb(skb);
 108                 priv->netdev->stats.rx_errors++;
 109                 return -EINVAL;
 110         }
 111
 112         /* If we change the header in loop mode, the checksum is corrupted. */
 113         if (priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP)
 114                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 115         else
 116                 skb->ip_summed = CHECKSUM_NONE;
 117
 118         netif_rx_any_context(skb);
 119
 120         /* Update statistics. */
 121         priv->netdev->stats.rx_packets++;
 122         priv->netdev->stats.rx_bytes += pktlen;
 123
 124         return 0;
 125 }
 126
 127 static int delete_device(struct chnl_net *dev)
 128 {
 129         ASSERT_RTNL();
 130         if (dev->netdev)
 131                 unregister_netdevice(dev->netdev);
 132         return 0;
 133 }
 134
 135 static void close_work(struct work_struct *work)
 136 {
 137         struct chnl_net *dev = NULL;
 138         struct list_head *list_node;
 139         struct list_head *_tmp;
 140
 141         rtnl_lock();
 142         list_for_each_safe(list_node, _tmp, &chnl_net_list) {
 143                 dev = list_entry(list_node, struct chnl_net, list_field);
 144                 if (dev->state == CAIF_SHUTDOWN)
 145                         dev_close(dev->netdev);
 146         }
 147         rtnl_unlock();
 148 }
 149 static DECLARE_WORK(close_worker, close_work);
 150
 151 static void chnl_hold(struct cflayer *lyr)
 152 {
 153         struct chnl_net *priv = container_of(lyr, struct chnl_net, chnl);
 154         dev_hold(priv->netdev);
 155 }
 156
 157 static void chnl_put(struct cflayer *lyr)
 158 {
 159         struct chnl_net *priv = container_of(lyr, struct chnl_net, chnl);
 160         dev_put(priv->netdev);
 161 }
 162
 163 static void chnl_flowctrl_cb(struct cflayer *layr, enum caif_ctrlcmd flow,
 164                              int phyid)
 165 {
 166         struct chnl_net *priv = container_of(layr, struct chnl_net, chnl);
 167         pr_debug("NET flowctrl func called flow: %s\n",
 168                 flow == CAIF_CTRLCMD_FLOW_ON_IND ? "ON" :
 169                 flow == CAIF_CTRLCMD_INIT_RSP ? "INIT" :
 170                 flow == CAIF_CTRLCMD_FLOW_OFF_IND ? "OFF" :
 171                 flow == CAIF_CTRLCMD_DEINIT_RSP ? "CLOSE/DEINIT" :
 172                 flow == CAIF_CTRLCMD_INIT_FAIL_RSP ? "OPEN_FAIL" :
 173                 flow == CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND ?
 174                  "REMOTE_SHUTDOWN" : "UNKNOWN CTRL COMMAND");
 175
 176
 177
 178         switch (flow) {
 179         case CAIF_CTRLCMD_FLOW_OFF_IND:
 180                 priv->flowenabled = false;
 181                 netif_stop_queue(priv->netdev);
 182                 break;
 183         case CAIF_CTRLCMD_DEINIT_RSP:
 184                 priv->state = CAIF_DISCONNECTED;
 185                 break;
 186         case CAIF_CTRLCMD_INIT_FAIL_RSP:
 187                 priv->state = CAIF_DISCONNECTED;
 188                 wake_up_interruptible(&priv->netmgmt_wq);
 189                 break;
 190         case CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND:
 191                 priv->state = CAIF_SHUTDOWN;
 192                 netif_tx_disable(priv->netdev);
 193                 schedule_work(&close_worker);
 194                 break;
 195         case CAIF_CTRLCMD_FLOW_ON_IND:
 196                 priv->flowenabled = true;
 197                 netif_wake_queue(priv->netdev);
 198                 break;
 199         case CAIF_CTRLCMD_INIT_RSP:
 200                 caif_client_register_refcnt(&priv->chnl, chnl_hold, chnl_put);
 201                 priv->state = CAIF_CONNECTED;
 202                 priv->flowenabled = true;
 203                 netif_wake_queue(priv->netdev);
 204                 wake_up_interruptible(&priv->netmgmt_wq);
 205                 break;
 206         default:
 207                 break;
 208         }
 209 }
 210
 211 static netdev_tx_t chnl_net_start_xmit(struct sk_buff *skb,
 212                                        struct net_device *dev)
 213 {
 214         struct chnl_net *priv;
 215         struct cfpkt *pkt = NULL;
 216         int len;
 217         int result = -1;
 218         /* Get our private data. */
 219         priv = netdev_priv(dev);
 220
 221         if (skb->len > priv->netdev->mtu) {
 222                 pr_warn("Size of skb exceeded MTU\n");
 223                 kfree_skb(skb);
 224                 dev->stats.tx_errors++;
 225                 return NETDEV_TX_OK;
 226         }
 227
 228         if (!priv->flowenabled) {
 229                 pr_debug("dropping packets flow off\n");
 230                 kfree_skb(skb);
 231                 dev->stats.tx_dropped++;
 232                 return NETDEV_TX_OK;
 233         }
 234
 235         if (priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP)
 236                 swap(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr);
 237
 238         /* Store original SKB length. */
 239         len = skb->len;
 240
 241         pkt = cfpkt_fromnative(CAIF_DIR_OUT, (void *) skb);
 242
 243         /* Send the packet down the stack. */
 244         result = priv->chnl.dn->transmit(priv->chnl.dn, pkt);
 245         if (result) {
 246                 dev->stats.tx_dropped++;
 247                 return NETDEV_TX_OK;
 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
 306                 if (mtu < 100) {
 307                         pr_warn("CAIF Interface MTU too small (%d)\n", mtu);
 308                         result = -ENODEV;
 309                         goto error;
 310                 }
 311         }
 312
 313         rtnl_unlock();  /* Release RTNL lock during connect wait */
 314
 315         result = wait_event_interruptible_timeout(priv->netmgmt_wq,
 316                                                 priv->state != CAIF_CONNECTING,
 317                                                 CONNECT_TIMEOUT);
 318
 319         rtnl_lock();
 320
 321         if (result == -ERESTARTSYS) {
 322                 pr_debug("wait_event_interruptible woken by a signal\n");
 323                 result = -ERESTARTSYS;
 324                 goto error;
 325         }
 326
 327         if (result == 0) {
 328                 pr_debug("connect timeout\n");
 329                 caif_disconnect_client(dev_net(dev), &priv->chnl);
 330                 priv->state = CAIF_DISCONNECTED;
 331                 pr_debug("state disconnected\n");
 332                 result = -ETIMEDOUT;
 333                 goto error;
 334         }
 335
 336         if (priv->state != CAIF_CONNECTED) {
 337                 pr_debug("connect failed\n");
 338                 result = -ECONNREFUSED;
 339                 goto error;
 340         }
 341         pr_debug("CAIF Netdevice connected\n");
 342         return 0;
 343
 344 error:
 345         caif_disconnect_client(dev_net(dev), &priv->chnl);
 346         priv->state = CAIF_DISCONNECTED;
 347         pr_debug("state disconnected\n");
 348         return result;
 349
 350 }
 351
 352 static int chnl_net_stop(struct net_device *dev)
 353 {
 354         struct chnl_net *priv;
 355
 356         ASSERT_RTNL();
 357         priv = netdev_priv(dev);
 358         priv->state = CAIF_DISCONNECTED;
 359         caif_disconnect_client(dev_net(dev), &priv->chnl);
 360         return 0;
 361 }
 362
 363 static int chnl_net_init(struct net_device *dev)
 364 {
 365         struct chnl_net *priv;
 366         ASSERT_RTNL();
 367         priv = netdev_priv(dev);
 368         strncpy(priv->name, dev->name, sizeof(priv->name));
 369         return 0;
 370 }
 371
 372 static void chnl_net_uninit(struct net_device *dev)
 373 {
 374         struct chnl_net *priv;
 375         ASSERT_RTNL();
 376         priv = netdev_priv(dev);
 377         robust_list_del(&priv->list_field);
 378 }
 379
 380 static const struct net_device_ops netdev_ops = {
 381         .ndo_open = chnl_net_open,
 382         .ndo_stop = chnl_net_stop,
 383         .ndo_init = chnl_net_init,
 384         .ndo_uninit = chnl_net_uninit,
 385         .ndo_start_xmit = chnl_net_start_xmit,
 386 };
 387
 388 static void chnl_net_destructor(struct net_device *dev)
 389 {
 390         struct chnl_net *priv = netdev_priv(dev);
 391         caif_free_client(&priv->chnl);
 392 }
 393
 394 static void ipcaif_net_setup(struct net_device *dev)
 395 {
 396         struct chnl_net *priv;
 397         dev->netdev_ops = &netdev_ops;
 398         dev->needs_free_netdev = true;
 399         dev->priv_destructor = chnl_net_destructor;
 400         dev->flags |= IFF_NOARP;
 401         dev->flags |= IFF_POINTOPOINT;
 402         dev->mtu = GPRS_PDP_MTU;
 403         dev->tx_queue_len = CAIF_NET_DEFAULT_QUEUE_LEN;
 404
 405         priv = netdev_priv(dev);
 406         priv->chnl.receive = chnl_recv_cb;
 407         priv->chnl.ctrlcmd = chnl_flowctrl_cb;
 408         priv->netdev = dev;
 409         priv->conn_req.protocol = CAIFPROTO_DATAGRAM;
 410         priv->conn_req.link_selector = CAIF_LINK_HIGH_BANDW;
 411         priv->conn_req.priority = CAIF_PRIO_LOW;
 412         /* Insert illegal value */
 413         priv->conn_req.sockaddr.u.dgm.connection_id = UNDEF_CONNID;
 414         priv->flowenabled = false;
 415
 416         init_waitqueue_head(&priv->netmgmt_wq);
 417 }
 418
 419
 420 static int ipcaif_fill_info(struct sk_buff *skb, const struct net_device *dev)
 421 {
 422         struct chnl_net *priv;
 423         u8 loop;
 424         priv = netdev_priv(dev);
 425         if (nla_put_u32(skb, IFLA_CAIF_IPV4_CONNID,
 426                         priv->conn_req.sockaddr.u.dgm.connection_id) ||
 427             nla_put_u32(skb, IFLA_CAIF_IPV6_CONNID,
 428                         priv->conn_req.sockaddr.u.dgm.connection_id))
 429                 goto nla_put_failure;
 430         loop = priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP;
 431         if (nla_put_u8(skb, IFLA_CAIF_LOOPBACK, loop))
 432                 goto nla_put_failure;
 433         return 0;
 434 nla_put_failure:
 435         return -EMSGSIZE;
 436
 437 }
 438
 439 static void caif_netlink_parms(struct nlattr *data[],
 440                                struct caif_connect_request *conn_req)
 441 {
 442         if (!data) {
 443                 pr_warn("no params data found\n");
 444                 return;
 445         }
 446         if (data[IFLA_CAIF_IPV4_CONNID])
 447                 conn_req->sockaddr.u.dgm.connection_id =
 448                         nla_get_u32(data[IFLA_CAIF_IPV4_CONNID]);
 449         if (data[IFLA_CAIF_IPV6_CONNID])
 450                 conn_req->sockaddr.u.dgm.connection_id =
 451                         nla_get_u32(data[IFLA_CAIF_IPV6_CONNID]);
 452         if (data[IFLA_CAIF_LOOPBACK]) {
 453                 if (nla_get_u8(data[IFLA_CAIF_LOOPBACK]))
 454                         conn_req->protocol = CAIFPROTO_DATAGRAM_LOOP;
 455                 else
 456                         conn_req->protocol = CAIFPROTO_DATAGRAM;
 457         }
 458 }
 459
 460 static int ipcaif_newlink(struct net *src_net, struct net_device *dev,
 461                           struct nlattr *tb[], struct nlattr *data[],
 462                           struct netlink_ext_ack *extack)
 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
 470         ret = register_netdevice(dev);
 471         if (ret)
 472                 pr_warn("device rtml registration failed\n");
 473         else
 474                 list_add(&caifdev->list_field, &chnl_net_list);
 475
 476         /* Use ifindex as connection id, and use loopback channel default. */
 477         if (caifdev->conn_req.sockaddr.u.dgm.connection_id == UNDEF_CONNID) {
 478                 caifdev->conn_req.sockaddr.u.dgm.connection_id = dev->ifindex;
 479                 caifdev->conn_req.protocol = CAIFPROTO_DATAGRAM_LOOP;
 480         }
 481         return ret;
 482 }
 483
 484 static int ipcaif_changelink(struct net_device *dev, struct nlattr *tb[],
 485                              struct nlattr *data[],
 486                              struct netlink_ext_ack *extack)
 487 {
 488         struct chnl_net *caifdev;
 489         ASSERT_RTNL();
 490         caifdev = netdev_priv(dev);
 491         caif_netlink_parms(data, &caifdev->conn_req);
 492         netdev_state_change(dev);
 493         return 0;
 494 }
 495
 496 static size_t ipcaif_get_size(const struct net_device *dev)
 497 {
 498         return
 499                 /* IFLA_CAIF_IPV4_CONNID */
 500                 nla_total_size(4) +
 501                 /* IFLA_CAIF_IPV6_CONNID */
 502                 nla_total_size(4) +
 503                 /* IFLA_CAIF_LOOPBACK */
 504                 nla_total_size(2) +
 505                 0;
 506 }
 507
 508 static const struct nla_policy ipcaif_policy[IFLA_CAIF_MAX + 1] = {
 509         [IFLA_CAIF_IPV4_CONNID]       = { .type = NLA_U32 },
 510         [IFLA_CAIF_IPV6_CONNID]       = { .type = NLA_U32 },
 511         [IFLA_CAIF_LOOPBACK]          = { .type = NLA_U8 }
 512 };
 513
 514
 515 static struct rtnl_link_ops ipcaif_link_ops __read_mostly = {
 516         .kind           = "caif",
 517         .priv_size      = sizeof(struct chnl_net),
 518         .setup          = ipcaif_net_setup,
 519         .maxtype        = IFLA_CAIF_MAX,
 520         .policy         = ipcaif_policy,
 521         .newlink        = ipcaif_newlink,
 522         .changelink     = ipcaif_changelink,
 523         .get_size       = ipcaif_get_size,
 524         .fill_info      = ipcaif_fill_info,
 525
 526 };
 527
 528 static int __init chnl_init_module(void)
 529 {
 530         return rtnl_link_register(&ipcaif_link_ops);
 531 }
 532
 533 static void __exit chnl_exit_module(void)
 534 {
 535         struct chnl_net *dev = NULL;
 536         struct list_head *list_node;
 537         struct list_head *_tmp;
 538         rtnl_link_unregister(&ipcaif_link_ops);
 539         rtnl_lock();
 540         list_for_each_safe(list_node, _tmp, &chnl_net_list) {
 541                 dev = list_entry(list_node, struct chnl_net, list_field);
 542                 list_del(list_node);
 543                 delete_device(dev);
 544         }
 545         rtnl_unlock();
 546 }
 547
 548 module_init(chnl_init_module);
 549 module_exit(chnl_exit_module);