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         if (in_interrupt())
 119                 netif_rx(skb);
 120         else
 121                 netif_rx_ni(skb);
 122
 123         /* Update statistics. */
 124         priv->netdev->stats.rx_packets++;
 125         priv->netdev->stats.rx_bytes += pktlen;
 126
 127         return 0;
 128 }
 129
 130 static int delete_device(struct chnl_net *dev)
 131 {
 132         ASSERT_RTNL();
 133         if (dev->netdev)
 134                 unregister_netdevice(dev->netdev);
 135         return 0;
 136 }
 137
 138 static void close_work(struct work_struct *work)
 139 {
 140         struct chnl_net *dev = NULL;
 141         struct list_head *list_node;
 142         struct list_head *_tmp;
 143
 144         rtnl_lock();
 145         list_for_each_safe(list_node, _tmp, &chnl_net_list) {
 146                 dev = list_entry(list_node, struct chnl_net, list_field);
 147                 if (dev->state == CAIF_SHUTDOWN)
 148                         dev_close(dev->netdev);
 149         }
 150         rtnl_unlock();
 151 }
 152 static DECLARE_WORK(close_worker, close_work);
 153
 154 static void chnl_hold(struct cflayer *lyr)
 155 {
 156         struct chnl_net *priv = container_of(lyr, struct chnl_net, chnl);
 157         dev_hold(priv->netdev);
 158 }
 159
 160 static void chnl_put(struct cflayer *lyr)
 161 {
 162         struct chnl_net *priv = container_of(lyr, struct chnl_net, chnl);
 163         dev_put(priv->netdev);
 164 }
 165
 166 static void chnl_flowctrl_cb(struct cflayer *layr, enum caif_ctrlcmd flow,
 167                              int phyid)
 168 {
 169         struct chnl_net *priv = container_of(layr, struct chnl_net, chnl);
 170         pr_debug("NET flowctrl func called flow: %s\n",
 171                 flow == CAIF_CTRLCMD_FLOW_ON_IND ? "ON" :
 172                 flow == CAIF_CTRLCMD_INIT_RSP ? "INIT" :
 173                 flow == CAIF_CTRLCMD_FLOW_OFF_IND ? "OFF" :
 174                 flow == CAIF_CTRLCMD_DEINIT_RSP ? "CLOSE/DEINIT" :
 175                 flow == CAIF_CTRLCMD_INIT_FAIL_RSP ? "OPEN_FAIL" :
 176                 flow == CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND ?
 177                  "REMOTE_SHUTDOWN" : "UNKNOWN CTRL COMMAND");
 178
 179
 180
 181         switch (flow) {
 182         case CAIF_CTRLCMD_FLOW_OFF_IND:
 183                 priv->flowenabled = false;
 184                 netif_stop_queue(priv->netdev);
 185                 break;
 186         case CAIF_CTRLCMD_DEINIT_RSP:
 187                 priv->state = CAIF_DISCONNECTED;
 188                 break;
 189         case CAIF_CTRLCMD_INIT_FAIL_RSP:
 190                 priv->state = CAIF_DISCONNECTED;
 191                 wake_up_interruptible(&priv->netmgmt_wq);
 192                 break;
 193         case CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND:
 194                 priv->state = CAIF_SHUTDOWN;
 195                 netif_tx_disable(priv->netdev);
 196                 schedule_work(&close_worker);
 197                 break;
 198         case CAIF_CTRLCMD_FLOW_ON_IND:
 199                 priv->flowenabled = true;
 200                 netif_wake_queue(priv->netdev);
 201                 break;
 202         case CAIF_CTRLCMD_INIT_RSP:
 203                 caif_client_register_refcnt(&priv->chnl, chnl_hold, chnl_put);
 204                 priv->state = CAIF_CONNECTED;
 205                 priv->flowenabled = true;
 206                 netif_wake_queue(priv->netdev);
 207                 wake_up_interruptible(&priv->netmgmt_wq);
 208                 break;
 209         default:
 210                 break;
 211         }
 212 }
 213
 214 static netdev_tx_t chnl_net_start_xmit(struct sk_buff *skb,
 215                                        struct net_device *dev)
 216 {
 217         struct chnl_net *priv;
 218         struct cfpkt *pkt = NULL;
 219         int len;
 220         int result = -1;
 221         /* Get our private data. */
 222         priv = netdev_priv(dev);
 223
 224         if (skb->len > priv->netdev->mtu) {
 225                 pr_warn("Size of skb exceeded MTU\n");
 226                 kfree_skb(skb);
 227                 dev->stats.tx_errors++;
 228                 return NETDEV_TX_OK;
 229         }
 230
 231         if (!priv->flowenabled) {
 232                 pr_debug("dropping packets flow off\n");
 233                 kfree_skb(skb);
 234                 dev->stats.tx_dropped++;
 235                 return NETDEV_TX_OK;
 236         }
 237
 238         if (priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP)
 239                 swap(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr);
 240
 241         /* Store original SKB length. */
 242         len = skb->len;
 243
 244         pkt = cfpkt_fromnative(CAIF_DIR_OUT, (void *) skb);
 245
 246         /* Send the packet down the stack. */
 247         result = priv->chnl.dn->transmit(priv->chnl.dn, pkt);
 248         if (result) {
 249                 dev->stats.tx_dropped++;
 250                 return NETDEV_TX_OK;
 251         }
 252
 253         /* Update statistics. */
 254         dev->stats.tx_packets++;
 255         dev->stats.tx_bytes += len;
 256
 257         return NETDEV_TX_OK;
 258 }
 259
 260 static int chnl_net_open(struct net_device *dev)
 261 {
 262         struct chnl_net *priv = NULL;
 263         int result = -1;
 264         int llifindex, headroom, tailroom, mtu;
 265         struct net_device *lldev;
 266         ASSERT_RTNL();
 267         priv = netdev_priv(dev);
 268         if (!priv) {
 269                 pr_debug("chnl_net_open: no priv\n");
 270                 return -ENODEV;
 271         }
 272
 273         if (priv->state != CAIF_CONNECTING) {
 274                 priv->state = CAIF_CONNECTING;
 275                 result = caif_connect_client(dev_net(dev), &priv->conn_req,
 276                                                 &priv->chnl, &llifindex,
 277                                                 &headroom, &tailroom);
 278                 if (result != 0) {
 279                                 pr_debug("err: "
 280                                          "Unable to register and open device,"
 281                                          " Err:%d\n",
 282                                          result);
 283                                 goto error;
 284                 }
 285
 286                 lldev = __dev_get_by_index(dev_net(dev), llifindex);
 287
 288                 if (lldev == NULL) {
 289                         pr_debug("no interface?\n");
 290                         result = -ENODEV;
 291                         goto error;
 292                 }
 293
 294                 dev->needed_tailroom = tailroom + lldev->needed_tailroom;
 295                 dev->hard_header_len = headroom + lldev->hard_header_len +
 296                         lldev->needed_tailroom;
 297
 298                 /*
 299                  * MTU, head-room etc is not know before we have a
 300                  * CAIF link layer device available. MTU calculation may
 301                  * override initial RTNL configuration.
 302                  * MTU is minimum of current mtu, link layer mtu pluss
 303                  * CAIF head and tail, and PDP GPRS contexts max MTU.
 304                  */
 305                 mtu = min_t(int, dev->mtu, lldev->mtu - (headroom + tailroom));
 306                 mtu = min_t(int, GPRS_PDP_MTU, mtu);
 307                 dev_set_mtu(dev, mtu);
 308
 309                 if (mtu < 100) {
 310                         pr_warn("CAIF Interface MTU too small (%d)\n", mtu);
 311                         result = -ENODEV;
 312                         goto error;
 313                 }
 314         }
 315
 316         rtnl_unlock();  /* Release RTNL lock during connect wait */
 317
 318         result = wait_event_interruptible_timeout(priv->netmgmt_wq,
 319                                                 priv->state != CAIF_CONNECTING,
 320                                                 CONNECT_TIMEOUT);
 321
 322         rtnl_lock();
 323
 324         if (result == -ERESTARTSYS) {
 325                 pr_debug("wait_event_interruptible woken by a signal\n");
 326                 result = -ERESTARTSYS;
 327                 goto error;
 328         }
 329
 330         if (result == 0) {
 331                 pr_debug("connect timeout\n");
 332                 caif_disconnect_client(dev_net(dev), &priv->chnl);
 333                 priv->state = CAIF_DISCONNECTED;
 334                 pr_debug("state disconnected\n");
 335                 result = -ETIMEDOUT;
 336                 goto error;
 337         }
 338
 339         if (priv->state != CAIF_CONNECTED) {
 340                 pr_debug("connect failed\n");
 341                 result = -ECONNREFUSED;
 342                 goto error;
 343         }
 344         pr_debug("CAIF Netdevice connected\n");
 345         return 0;
 346
 347 error:
 348         caif_disconnect_client(dev_net(dev), &priv->chnl);
 349         priv->state = CAIF_DISCONNECTED;
 350         pr_debug("state disconnected\n");
 351         return result;
 352
 353 }
 354
 355 static int chnl_net_stop(struct net_device *dev)
 356 {
 357         struct chnl_net *priv;
 358
 359         ASSERT_RTNL();
 360         priv = netdev_priv(dev);
 361         priv->state = CAIF_DISCONNECTED;
 362         caif_disconnect_client(dev_net(dev), &priv->chnl);
 363         return 0;
 364 }
 365
 366 static int chnl_net_init(struct net_device *dev)
 367 {
 368         struct chnl_net *priv;
 369         ASSERT_RTNL();
 370         priv = netdev_priv(dev);
 371         strncpy(priv->name, dev->name, sizeof(priv->name));
 372         return 0;
 373 }
 374
 375 static void chnl_net_uninit(struct net_device *dev)
 376 {
 377         struct chnl_net *priv;
 378         ASSERT_RTNL();
 379         priv = netdev_priv(dev);
 380         robust_list_del(&priv->list_field);
 381 }
 382
 383 static const struct net_device_ops netdev_ops = {
 384         .ndo_open = chnl_net_open,
 385         .ndo_stop = chnl_net_stop,
 386         .ndo_init = chnl_net_init,
 387         .ndo_uninit = chnl_net_uninit,
 388         .ndo_start_xmit = chnl_net_start_xmit,
 389 };
 390
 391 static void chnl_net_destructor(struct net_device *dev)
 392 {
 393         struct chnl_net *priv = netdev_priv(dev);
 394         caif_free_client(&priv->chnl);
 395 }
 396
 397 static void ipcaif_net_setup(struct net_device *dev)
 398 {
 399         struct chnl_net *priv;
 400         dev->netdev_ops = &netdev_ops;
 401         dev->needs_free_netdev = true;
 402         dev->priv_destructor = chnl_net_destructor;
 403         dev->flags |= IFF_NOARP;
 404         dev->flags |= IFF_POINTOPOINT;
 405         dev->mtu = GPRS_PDP_MTU;
 406         dev->tx_queue_len = CAIF_NET_DEFAULT_QUEUE_LEN;
 407
 408         priv = netdev_priv(dev);
 409         priv->chnl.receive = chnl_recv_cb;
 410         priv->chnl.ctrlcmd = chnl_flowctrl_cb;
 411         priv->netdev = dev;
 412         priv->conn_req.protocol = CAIFPROTO_DATAGRAM;
 413         priv->conn_req.link_selector = CAIF_LINK_HIGH_BANDW;
 414         priv->conn_req.priority = CAIF_PRIO_LOW;
 415         /* Insert illegal value */
 416         priv->conn_req.sockaddr.u.dgm.connection_id = UNDEF_CONNID;
 417         priv->flowenabled = false;
 418
 419         init_waitqueue_head(&priv->netmgmt_wq);
 420 }
 421
 422
 423 static int ipcaif_fill_info(struct sk_buff *skb, const struct net_device *dev)
 424 {
 425         struct chnl_net *priv;
 426         u8 loop;
 427         priv = netdev_priv(dev);
 428         if (nla_put_u32(skb, IFLA_CAIF_IPV4_CONNID,
 429                         priv->conn_req.sockaddr.u.dgm.connection_id) ||
 430             nla_put_u32(skb, IFLA_CAIF_IPV6_CONNID,
 431                         priv->conn_req.sockaddr.u.dgm.connection_id))
 432                 goto nla_put_failure;
 433         loop = priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP;
 434         if (nla_put_u8(skb, IFLA_CAIF_LOOPBACK, loop))
 435                 goto nla_put_failure;
 436         return 0;
 437 nla_put_failure:
 438         return -EMSGSIZE;
 439
 440 }
 441
 442 static void caif_netlink_parms(struct nlattr *data[],
 443                                struct caif_connect_request *conn_req)
 444 {
 445         if (!data) {
 446                 pr_warn("no params data found\n");
 447                 return;
 448         }
 449         if (data[IFLA_CAIF_IPV4_CONNID])
 450                 conn_req->sockaddr.u.dgm.connection_id =
 451                         nla_get_u32(data[IFLA_CAIF_IPV4_CONNID]);
 452         if (data[IFLA_CAIF_IPV6_CONNID])
 453                 conn_req->sockaddr.u.dgm.connection_id =
 454                         nla_get_u32(data[IFLA_CAIF_IPV6_CONNID]);
 455         if (data[IFLA_CAIF_LOOPBACK]) {
 456                 if (nla_get_u8(data[IFLA_CAIF_LOOPBACK]))
 457                         conn_req->protocol = CAIFPROTO_DATAGRAM_LOOP;
 458                 else
 459                         conn_req->protocol = CAIFPROTO_DATAGRAM;
 460         }
 461 }
 462
 463 static int ipcaif_newlink(struct net *src_net, struct net_device *dev,
 464                           struct nlattr *tb[], struct nlattr *data[],
 465                           struct netlink_ext_ack *extack)
 466 {
 467         int ret;
 468         struct chnl_net *caifdev;
 469         ASSERT_RTNL();
 470         caifdev = netdev_priv(dev);
 471         caif_netlink_parms(data, &caifdev->conn_req);
 472
 473         ret = register_netdevice(dev);
 474         if (ret)
 475                 pr_warn("device rtml registration failed\n");
 476         else
 477                 list_add(&caifdev->list_field, &chnl_net_list);
 478
 479         /* Use ifindex as connection id, and use loopback channel default. */
 480         if (caifdev->conn_req.sockaddr.u.dgm.connection_id == UNDEF_CONNID) {
 481                 caifdev->conn_req.sockaddr.u.dgm.connection_id = dev->ifindex;
 482                 caifdev->conn_req.protocol = CAIFPROTO_DATAGRAM_LOOP;
 483         }
 484         return ret;
 485 }
 486
 487 static int ipcaif_changelink(struct net_device *dev, struct nlattr *tb[],
 488                              struct nlattr *data[],
 489                              struct netlink_ext_ack *extack)
 490 {
 491         struct chnl_net *caifdev;
 492         ASSERT_RTNL();
 493         caifdev = netdev_priv(dev);
 494         caif_netlink_parms(data, &caifdev->conn_req);
 495         netdev_state_change(dev);
 496         return 0;
 497 }
 498
 499 static size_t ipcaif_get_size(const struct net_device *dev)
 500 {
 501         return
 502                 /* IFLA_CAIF_IPV4_CONNID */
 503                 nla_total_size(4) +
 504                 /* IFLA_CAIF_IPV6_CONNID */
 505                 nla_total_size(4) +
 506                 /* IFLA_CAIF_LOOPBACK */
 507                 nla_total_size(2) +
 508                 0;
 509 }
 510
 511 static const struct nla_policy ipcaif_policy[IFLA_CAIF_MAX + 1] = {
 512         [IFLA_CAIF_IPV4_CONNID]       = { .type = NLA_U32 },
 513         [IFLA_CAIF_IPV6_CONNID]       = { .type = NLA_U32 },
 514         [IFLA_CAIF_LOOPBACK]          = { .type = NLA_U8 }
 515 };
 516
 517
 518 static struct rtnl_link_ops ipcaif_link_ops __read_mostly = {
 519         .kind           = "caif",
 520         .priv_size      = sizeof(struct chnl_net),
 521         .setup          = ipcaif_net_setup,
 522         .maxtype        = IFLA_CAIF_MAX,
 523         .policy         = ipcaif_policy,
 524         .newlink        = ipcaif_newlink,
 525         .changelink     = ipcaif_changelink,
 526         .get_size       = ipcaif_get_size,
 527         .fill_info      = ipcaif_fill_info,
 528
 529 };
 530
 531 static int __init chnl_init_module(void)
 532 {
 533         return rtnl_link_register(&ipcaif_link_ops);
 534 }
 535
 536 static void __exit chnl_exit_module(void)
 537 {
 538         struct chnl_net *dev = NULL;
 539         struct list_head *list_node;
 540         struct list_head *_tmp;
 541         rtnl_link_unregister(&ipcaif_link_ops);
 542         rtnl_lock();
 543         list_for_each_safe(list_node, _tmp, &chnl_net_list) {
 544                 dev = list_entry(list_node, struct chnl_net, list_field);
 545                 list_del(list_node);
 546                 delete_device(dev);
 547         }
 548         rtnl_unlock();
 549 }
 550
 551 module_init(chnl_init_module);
 552 module_exit(chnl_exit_module);