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_DESCRIPTION("ST-Ericsson CAIF modem protocol GPRS network device");
  35 MODULE_LICENSE("GPL");
  36 MODULE_ALIAS_RTNL_LINK("caif");
  37
  38 enum caif_states {
  39         CAIF_CONNECTED          = 1,
  40         CAIF_CONNECTING,
  41         CAIF_DISCONNECTED,
  42         CAIF_SHUTDOWN
  43 };
  44
  45 struct chnl_net {
  46         struct cflayer chnl;
  47         struct caif_connect_request conn_req;
  48         struct list_head list_field;
  49         struct net_device *netdev;
  50         char name[256];
  51         wait_queue_head_t netmgmt_wq;
  52         /* Flow status to remember and control the transmission. */
  53         bool flowenabled;
  54         enum caif_states state;
  55 };
  56
  57 static int chnl_recv_cb(struct cflayer *layr, struct cfpkt *pkt)
  58 {
  59         struct sk_buff *skb;
  60         struct chnl_net *priv;
  61         int pktlen;
  62         const u8 *ip_version;
  63         u8 buf;
  64
  65         priv = container_of(layr, struct chnl_net, chnl);
  66
  67         skb = (struct sk_buff *) cfpkt_tonative(pkt);
  68
  69         /* Get length of CAIF packet. */
  70         pktlen = skb->len;
  71
  72         /* Pass some minimum information and
  73          * send the packet to the net stack.
  74          */
  75         skb->dev = priv->netdev;
  76
  77         /* check the version of IP */
  78         ip_version = skb_header_pointer(skb, 0, 1, &buf);
  79         if (!ip_version) {
  80                 kfree_skb(skb);
  81                 return -EINVAL;
  82         }
  83
  84         switch (*ip_version >> 4) {
  85         case 4:
  86                 skb->protocol = htons(ETH_P_IP);
  87                 break;
  88         case 6:
  89                 skb->protocol = htons(ETH_P_IPV6);
  90                 break;
  91         default:
  92                 kfree_skb(skb);
  93                 priv->netdev->stats.rx_errors++;
  94                 return -EINVAL;
  95         }
  96
  97         /* If we change the header in loop mode, the checksum is corrupted. */
  98         if (priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP)
  99                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 100         else
 101                 skb->ip_summed = CHECKSUM_NONE;
 102
 103         netif_rx(skb);
 104
 105         /* Update statistics. */
 106         priv->netdev->stats.rx_packets++;
 107         priv->netdev->stats.rx_bytes += pktlen;
 108
 109         return 0;
 110 }
 111
 112 static int delete_device(struct chnl_net *dev)
 113 {
 114         ASSERT_RTNL();
 115         if (dev->netdev)
 116                 unregister_netdevice(dev->netdev);
 117         return 0;
 118 }
 119
 120 static void close_work(struct work_struct *work)
 121 {
 122         struct chnl_net *dev = NULL;
 123         struct list_head *list_node;
 124         struct list_head *_tmp;
 125
 126         rtnl_lock();
 127         list_for_each_safe(list_node, _tmp, &chnl_net_list) {
 128                 dev = list_entry(list_node, struct chnl_net, list_field);
 129                 if (dev->state == CAIF_SHUTDOWN)
 130                         dev_close(dev->netdev);
 131         }
 132         rtnl_unlock();
 133 }
 134 static DECLARE_WORK(close_worker, close_work);
 135
 136 static void chnl_hold(struct cflayer *lyr)
 137 {
 138         struct chnl_net *priv = container_of(lyr, struct chnl_net, chnl);
 139         dev_hold(priv->netdev);
 140 }
 141
 142 static void chnl_put(struct cflayer *lyr)
 143 {
 144         struct chnl_net *priv = container_of(lyr, struct chnl_net, chnl);
 145         dev_put(priv->netdev);
 146 }
 147
 148 static void chnl_flowctrl_cb(struct cflayer *layr, enum caif_ctrlcmd flow,
 149                              int phyid)
 150 {
 151         struct chnl_net *priv = container_of(layr, struct chnl_net, chnl);
 152         pr_debug("NET flowctrl func called flow: %s\n",
 153                 flow == CAIF_CTRLCMD_FLOW_ON_IND ? "ON" :
 154                 flow == CAIF_CTRLCMD_INIT_RSP ? "INIT" :
 155                 flow == CAIF_CTRLCMD_FLOW_OFF_IND ? "OFF" :
 156                 flow == CAIF_CTRLCMD_DEINIT_RSP ? "CLOSE/DEINIT" :
 157                 flow == CAIF_CTRLCMD_INIT_FAIL_RSP ? "OPEN_FAIL" :
 158                 flow == CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND ?
 159                  "REMOTE_SHUTDOWN" : "UNKNOWN CTRL COMMAND");
 160
 161
 162
 163         switch (flow) {
 164         case CAIF_CTRLCMD_FLOW_OFF_IND:
 165                 priv->flowenabled = false;
 166                 netif_stop_queue(priv->netdev);
 167                 break;
 168         case CAIF_CTRLCMD_DEINIT_RSP:
 169                 priv->state = CAIF_DISCONNECTED;
 170                 break;
 171         case CAIF_CTRLCMD_INIT_FAIL_RSP:
 172                 priv->state = CAIF_DISCONNECTED;
 173                 wake_up_interruptible(&priv->netmgmt_wq);
 174                 break;
 175         case CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND:
 176                 priv->state = CAIF_SHUTDOWN;
 177                 netif_tx_disable(priv->netdev);
 178                 schedule_work(&close_worker);
 179                 break;
 180         case CAIF_CTRLCMD_FLOW_ON_IND:
 181                 priv->flowenabled = true;
 182                 netif_wake_queue(priv->netdev);
 183                 break;
 184         case CAIF_CTRLCMD_INIT_RSP:
 185                 caif_client_register_refcnt(&priv->chnl, chnl_hold, chnl_put);
 186                 priv->state = CAIF_CONNECTED;
 187                 priv->flowenabled = true;
 188                 netif_wake_queue(priv->netdev);
 189                 wake_up_interruptible(&priv->netmgmt_wq);
 190                 break;
 191         default:
 192                 break;
 193         }
 194 }
 195
 196 static netdev_tx_t chnl_net_start_xmit(struct sk_buff *skb,
 197                                        struct net_device *dev)
 198 {
 199         struct chnl_net *priv;
 200         struct cfpkt *pkt = NULL;
 201         int len;
 202         int result = -1;
 203         /* Get our private data. */
 204         priv = netdev_priv(dev);
 205
 206         if (skb->len > priv->netdev->mtu) {
 207                 pr_warn("Size of skb exceeded MTU\n");
 208                 kfree_skb(skb);
 209                 dev->stats.tx_errors++;
 210                 return NETDEV_TX_OK;
 211         }
 212
 213         if (!priv->flowenabled) {
 214                 pr_debug("dropping packets flow off\n");
 215                 kfree_skb(skb);
 216                 dev->stats.tx_dropped++;
 217                 return NETDEV_TX_OK;
 218         }
 219
 220         if (priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP)
 221                 swap(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr);
 222
 223         /* Store original SKB length. */
 224         len = skb->len;
 225
 226         pkt = cfpkt_fromnative(CAIF_DIR_OUT, (void *) skb);
 227
 228         /* Send the packet down the stack. */
 229         result = priv->chnl.dn->transmit(priv->chnl.dn, pkt);
 230         if (result) {
 231                 dev->stats.tx_dropped++;
 232                 return NETDEV_TX_OK;
 233         }
 234
 235         /* Update statistics. */
 236         dev->stats.tx_packets++;
 237         dev->stats.tx_bytes += len;
 238
 239         return NETDEV_TX_OK;
 240 }
 241
 242 static int chnl_net_open(struct net_device *dev)
 243 {
 244         struct chnl_net *priv = NULL;
 245         int result = -1;
 246         int llifindex, headroom, tailroom, mtu;
 247         struct net_device *lldev;
 248         ASSERT_RTNL();
 249         priv = netdev_priv(dev);
 250         if (!priv) {
 251                 pr_debug("chnl_net_open: no priv\n");
 252                 return -ENODEV;
 253         }
 254
 255         if (priv->state != CAIF_CONNECTING) {
 256                 priv->state = CAIF_CONNECTING;
 257                 result = caif_connect_client(dev_net(dev), &priv->conn_req,
 258                                                 &priv->chnl, &llifindex,
 259                                                 &headroom, &tailroom);
 260                 if (result != 0) {
 261                                 pr_debug("err: "
 262                                          "Unable to register and open device,"
 263                                          " Err:%d\n",
 264                                          result);
 265                                 goto error;
 266                 }
 267
 268                 lldev = __dev_get_by_index(dev_net(dev), llifindex);
 269
 270                 if (lldev == NULL) {
 271                         pr_debug("no interface?\n");
 272                         result = -ENODEV;
 273                         goto error;
 274                 }
 275
 276                 dev->needed_tailroom = tailroom + lldev->needed_tailroom;
 277                 dev->hard_header_len = headroom + lldev->hard_header_len +
 278                         lldev->needed_tailroom;
 279
 280                 /*
 281                  * MTU, head-room etc is not know before we have a
 282                  * CAIF link layer device available. MTU calculation may
 283                  * override initial RTNL configuration.
 284                  * MTU is minimum of current mtu, link layer mtu pluss
 285                  * CAIF head and tail, and PDP GPRS contexts max MTU.
 286                  */
 287                 mtu = min_t(int, dev->mtu, lldev->mtu - (headroom + tailroom));
 288                 mtu = min_t(int, GPRS_PDP_MTU, mtu);
 289                 dev_set_mtu(dev, mtu);
 290
 291                 if (mtu < 100) {
 292                         pr_warn("CAIF Interface MTU too small (%d)\n", mtu);
 293                         result = -ENODEV;
 294                         goto error;
 295                 }
 296         }
 297
 298         rtnl_unlock();  /* Release RTNL lock during connect wait */
 299
 300         result = wait_event_interruptible_timeout(priv->netmgmt_wq,
 301                                                 priv->state != CAIF_CONNECTING,
 302                                                 CONNECT_TIMEOUT);
 303
 304         rtnl_lock();
 305
 306         if (result == -ERESTARTSYS) {
 307                 pr_debug("wait_event_interruptible woken by a signal\n");
 308                 result = -ERESTARTSYS;
 309                 goto error;
 310         }
 311
 312         if (result == 0) {
 313                 pr_debug("connect timeout\n");
 314                 result = -ETIMEDOUT;
 315                 goto error;
 316         }
 317
 318         if (priv->state != CAIF_CONNECTED) {
 319                 pr_debug("connect failed\n");
 320                 result = -ECONNREFUSED;
 321                 goto error;
 322         }
 323         pr_debug("CAIF Netdevice connected\n");
 324         return 0;
 325
 326 error:
 327         caif_disconnect_client(dev_net(dev), &priv->chnl);
 328         priv->state = CAIF_DISCONNECTED;
 329         pr_debug("state disconnected\n");
 330         return result;
 331
 332 }
 333
 334 static int chnl_net_stop(struct net_device *dev)
 335 {
 336         struct chnl_net *priv;
 337
 338         ASSERT_RTNL();
 339         priv = netdev_priv(dev);
 340         priv->state = CAIF_DISCONNECTED;
 341         caif_disconnect_client(dev_net(dev), &priv->chnl);
 342         return 0;
 343 }
 344
 345 static int chnl_net_init(struct net_device *dev)
 346 {
 347         struct chnl_net *priv;
 348         ASSERT_RTNL();
 349         priv = netdev_priv(dev);
 350         strncpy(priv->name, dev->name, sizeof(priv->name));
 351         INIT_LIST_HEAD(&priv->list_field);
 352         return 0;
 353 }
 354
 355 static void chnl_net_uninit(struct net_device *dev)
 356 {
 357         struct chnl_net *priv;
 358         ASSERT_RTNL();
 359         priv = netdev_priv(dev);
 360         list_del_init(&priv->list_field);
 361 }
 362
 363 static const struct net_device_ops netdev_ops = {
 364         .ndo_open = chnl_net_open,
 365         .ndo_stop = chnl_net_stop,
 366         .ndo_init = chnl_net_init,
 367         .ndo_uninit = chnl_net_uninit,
 368         .ndo_start_xmit = chnl_net_start_xmit,
 369 };
 370
 371 static void chnl_net_destructor(struct net_device *dev)
 372 {
 373         struct chnl_net *priv = netdev_priv(dev);
 374         caif_free_client(&priv->chnl);
 375 }
 376
 377 static void ipcaif_net_setup(struct net_device *dev)
 378 {
 379         struct chnl_net *priv;
 380         dev->netdev_ops = &netdev_ops;
 381         dev->needs_free_netdev = true;
 382         dev->priv_destructor = chnl_net_destructor;
 383         dev->flags |= IFF_NOARP;
 384         dev->flags |= IFF_POINTOPOINT;
 385         dev->mtu = GPRS_PDP_MTU;
 386         dev->tx_queue_len = CAIF_NET_DEFAULT_QUEUE_LEN;
 387
 388         priv = netdev_priv(dev);
 389         priv->chnl.receive = chnl_recv_cb;
 390         priv->chnl.ctrlcmd = chnl_flowctrl_cb;
 391         priv->netdev = dev;
 392         priv->conn_req.protocol = CAIFPROTO_DATAGRAM;
 393         priv->conn_req.link_selector = CAIF_LINK_HIGH_BANDW;
 394         priv->conn_req.priority = CAIF_PRIO_LOW;
 395         /* Insert illegal value */
 396         priv->conn_req.sockaddr.u.dgm.connection_id = UNDEF_CONNID;
 397         priv->flowenabled = false;
 398
 399         init_waitqueue_head(&priv->netmgmt_wq);
 400 }
 401
 402
 403 static int ipcaif_fill_info(struct sk_buff *skb, const struct net_device *dev)
 404 {
 405         struct chnl_net *priv;
 406         u8 loop;
 407         priv = netdev_priv(dev);
 408         if (nla_put_u32(skb, IFLA_CAIF_IPV4_CONNID,
 409                         priv->conn_req.sockaddr.u.dgm.connection_id) ||
 410             nla_put_u32(skb, IFLA_CAIF_IPV6_CONNID,
 411                         priv->conn_req.sockaddr.u.dgm.connection_id))
 412                 goto nla_put_failure;
 413         loop = priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP;
 414         if (nla_put_u8(skb, IFLA_CAIF_LOOPBACK, loop))
 415                 goto nla_put_failure;
 416         return 0;
 417 nla_put_failure:
 418         return -EMSGSIZE;
 419
 420 }
 421
 422 static void caif_netlink_parms(struct nlattr *data[],
 423                                struct caif_connect_request *conn_req)
 424 {
 425         if (!data) {
 426                 pr_warn("no params data found\n");
 427                 return;
 428         }
 429         if (data[IFLA_CAIF_IPV4_CONNID])
 430                 conn_req->sockaddr.u.dgm.connection_id =
 431                         nla_get_u32(data[IFLA_CAIF_IPV4_CONNID]);
 432         if (data[IFLA_CAIF_IPV6_CONNID])
 433                 conn_req->sockaddr.u.dgm.connection_id =
 434                         nla_get_u32(data[IFLA_CAIF_IPV6_CONNID]);
 435         if (data[IFLA_CAIF_LOOPBACK]) {
 436                 if (nla_get_u8(data[IFLA_CAIF_LOOPBACK]))
 437                         conn_req->protocol = CAIFPROTO_DATAGRAM_LOOP;
 438                 else
 439                         conn_req->protocol = CAIFPROTO_DATAGRAM;
 440         }
 441 }
 442
 443 static int ipcaif_newlink(struct net *src_net, struct net_device *dev,
 444                           struct nlattr *tb[], struct nlattr *data[],
 445                           struct netlink_ext_ack *extack)
 446 {
 447         int ret;
 448         struct chnl_net *caifdev;
 449         ASSERT_RTNL();
 450         caifdev = netdev_priv(dev);
 451         caif_netlink_parms(data, &caifdev->conn_req);
 452
 453         ret = register_netdevice(dev);
 454         if (ret)
 455                 pr_warn("device rtml registration failed\n");
 456         else
 457                 list_add(&caifdev->list_field, &chnl_net_list);
 458
 459         /* Use ifindex as connection id, and use loopback channel default. */
 460         if (caifdev->conn_req.sockaddr.u.dgm.connection_id == UNDEF_CONNID) {
 461                 caifdev->conn_req.sockaddr.u.dgm.connection_id = dev->ifindex;
 462                 caifdev->conn_req.protocol = CAIFPROTO_DATAGRAM_LOOP;
 463         }
 464         return ret;
 465 }
 466
 467 static int ipcaif_changelink(struct net_device *dev, struct nlattr *tb[],
 468                              struct nlattr *data[],
 469                              struct netlink_ext_ack *extack)
 470 {
 471         struct chnl_net *caifdev;
 472         ASSERT_RTNL();
 473         caifdev = netdev_priv(dev);
 474         caif_netlink_parms(data, &caifdev->conn_req);
 475         netdev_state_change(dev);
 476         return 0;
 477 }
 478
 479 static size_t ipcaif_get_size(const struct net_device *dev)
 480 {
 481         return
 482                 /* IFLA_CAIF_IPV4_CONNID */
 483                 nla_total_size(4) +
 484                 /* IFLA_CAIF_IPV6_CONNID */
 485                 nla_total_size(4) +
 486                 /* IFLA_CAIF_LOOPBACK */
 487                 nla_total_size(2) +
 488                 0;
 489 }
 490
 491 static const struct nla_policy ipcaif_policy[IFLA_CAIF_MAX + 1] = {
 492         [IFLA_CAIF_IPV4_CONNID]       = { .type = NLA_U32 },
 493         [IFLA_CAIF_IPV6_CONNID]       = { .type = NLA_U32 },
 494         [IFLA_CAIF_LOOPBACK]          = { .type = NLA_U8 }
 495 };
 496
 497
 498 static struct rtnl_link_ops ipcaif_link_ops __read_mostly = {
 499         .kind           = "caif",
 500         .priv_size      = sizeof(struct chnl_net),
 501         .setup          = ipcaif_net_setup,
 502         .maxtype        = IFLA_CAIF_MAX,
 503         .policy         = ipcaif_policy,
 504         .newlink        = ipcaif_newlink,
 505         .changelink     = ipcaif_changelink,
 506         .get_size       = ipcaif_get_size,
 507         .fill_info      = ipcaif_fill_info,
 508
 509 };
 510
 511 static int __init chnl_init_module(void)
 512 {
 513         return rtnl_link_register(&ipcaif_link_ops);
 514 }
 515
 516 static void __exit chnl_exit_module(void)
 517 {
 518         struct chnl_net *dev = NULL;
 519         struct list_head *list_node;
 520         struct list_head *_tmp;
 521         rtnl_link_unregister(&ipcaif_link_ops);
 522         rtnl_lock();
 523         list_for_each_safe(list_node, _tmp, &chnl_net_list) {
 524                 dev = list_entry(list_node, struct chnl_net, list_field);
 525                 list_del_init(list_node);
 526                 delete_device(dev);
 527         }
 528         rtnl_unlock();
 529 }
 530
 531 module_init(chnl_init_module);
 532 module_exit(chnl_exit_module);