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Linux/net/caif/chnl_net.c

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  1 /*
  2  * Copyright (C) ST-Ericsson AB 2010
  3  * Authors:     Sjur Brendeland
  4  *              Daniel Martensson
  5  * License terms: GNU General Public License (GPL) version 2
  6  */
  7 
  8 #define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
  9 
 10 #include <linux/fs.h>
 11 #include <linux/hardirq.h>
 12 #include <linux/init.h>
 13 #include <linux/module.h>
 14 #include <linux/netdevice.h>
 15 #include <linux/if_ether.h>
 16 #include <linux/moduleparam.h>
 17 #include <linux/ip.h>
 18 #include <linux/sched.h>
 19 #include <linux/sockios.h>
 20 #include <linux/caif/if_caif.h>
 21 #include <net/rtnetlink.h>
 22 #include <net/caif/caif_layer.h>
 23 #include <net/caif/cfpkt.h>
 24 #include <net/caif/caif_dev.h>
 25 
 26 /* GPRS PDP connection has MTU to 1500 */
 27 #define GPRS_PDP_MTU 1500
 28 /* 5 sec. connect timeout */
 29 #define CONNECT_TIMEOUT (5 * HZ)
 30 #define CAIF_NET_DEFAULT_QUEUE_LEN 500
 31 #define UNDEF_CONNID 0xffffffff
 32 
 33 /*This list is protected by the rtnl lock. */
 34 static LIST_HEAD(chnl_net_list);
 35 
 36 MODULE_LICENSE("GPL");
 37 MODULE_ALIAS_RTNL_LINK("caif");
 38 
 39 enum caif_states {
 40         CAIF_CONNECTED          = 1,
 41         CAIF_CONNECTING,
 42         CAIF_DISCONNECTED,
 43         CAIF_SHUTDOWN
 44 };
 45 
 46 struct chnl_net {
 47         struct cflayer chnl;
 48         struct net_device_stats stats;
 49         struct caif_connect_request conn_req;
 50         struct list_head list_field;
 51         struct net_device *netdev;
 52         char name[256];
 53         wait_queue_head_t netmgmt_wq;
 54         /* Flow status to remember and control the transmission. */
 55         bool flowenabled;
 56         enum caif_states state;
 57 };
 58 
 59 static void robust_list_del(struct list_head *delete_node)
 60 {
 61         struct list_head *list_node;
 62         struct list_head *n;
 63         ASSERT_RTNL();
 64         list_for_each_safe(list_node, n, &chnl_net_list) {
 65                 if (list_node == delete_node) {
 66                         list_del(list_node);
 67                         return;
 68                 }
 69         }
 70         WARN_ON(1);
 71 }
 72 
 73 static int chnl_recv_cb(struct cflayer *layr, struct cfpkt *pkt)
 74 {
 75         struct sk_buff *skb;
 76         struct chnl_net *priv;
 77         int pktlen;
 78         const u8 *ip_version;
 79         u8 buf;
 80 
 81         priv = container_of(layr, struct chnl_net, chnl);
 82         if (!priv)
 83                 return -EINVAL;
 84 
 85         skb = (struct sk_buff *) cfpkt_tonative(pkt);
 86 
 87         /* Get length of CAIF packet. */
 88         pktlen = skb->len;
 89 
 90         /* Pass some minimum information and
 91          * send the packet to the net stack.
 92          */
 93         skb->dev = priv->netdev;
 94 
 95         /* check the version of IP */
 96         ip_version = skb_header_pointer(skb, 0, 1, &buf);
 97         if (!ip_version) {
 98                 kfree_skb(skb);
 99                 return -EINVAL;
100         }
101 
102         switch (*ip_version >> 4) {
103         case 4:
104                 skb->protocol = htons(ETH_P_IP);
105                 break;
106         case 6:
107                 skb->protocol = htons(ETH_P_IPV6);
108                 break;
109         default:
110                 kfree_skb(skb);
111                 priv->netdev->stats.rx_errors++;
112                 return -EINVAL;
113         }
114 
115         /* If we change the header in loop mode, the checksum is corrupted. */
116         if (priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP)
117                 skb->ip_summed = CHECKSUM_UNNECESSARY;
118         else
119                 skb->ip_summed = CHECKSUM_NONE;
120 
121         if (in_interrupt())
122                 netif_rx(skb);
123         else
124                 netif_rx_ni(skb);
125 
126         /* Update statistics. */
127         priv->netdev->stats.rx_packets++;
128         priv->netdev->stats.rx_bytes += pktlen;
129 
130         return 0;
131 }
132 
133 static int delete_device(struct chnl_net *dev)
134 {
135         ASSERT_RTNL();
136         if (dev->netdev)
137                 unregister_netdevice(dev->netdev);
138         return 0;
139 }
140 
141 static void close_work(struct work_struct *work)
142 {
143         struct chnl_net *dev = NULL;
144         struct list_head *list_node;
145         struct list_head *_tmp;
146 
147         rtnl_lock();
148         list_for_each_safe(list_node, _tmp, &chnl_net_list) {
149                 dev = list_entry(list_node, struct chnl_net, list_field);
150                 if (dev->state == CAIF_SHUTDOWN)
151                         dev_close(dev->netdev);
152         }
153         rtnl_unlock();
154 }
155 static DECLARE_WORK(close_worker, close_work);
156 
157 static void chnl_hold(struct cflayer *lyr)
158 {
159         struct chnl_net *priv = container_of(lyr, struct chnl_net, chnl);
160         dev_hold(priv->netdev);
161 }
162 
163 static void chnl_put(struct cflayer *lyr)
164 {
165         struct chnl_net *priv = container_of(lyr, struct chnl_net, chnl);
166         dev_put(priv->netdev);
167 }
168 
169 static void chnl_flowctrl_cb(struct cflayer *layr, enum caif_ctrlcmd flow,
170                              int phyid)
171 {
172         struct chnl_net *priv = container_of(layr, struct chnl_net, chnl);
173         pr_debug("NET flowctrl func called flow: %s\n",
174                 flow == CAIF_CTRLCMD_FLOW_ON_IND ? "ON" :
175                 flow == CAIF_CTRLCMD_INIT_RSP ? "INIT" :
176                 flow == CAIF_CTRLCMD_FLOW_OFF_IND ? "OFF" :
177                 flow == CAIF_CTRLCMD_DEINIT_RSP ? "CLOSE/DEINIT" :
178                 flow == CAIF_CTRLCMD_INIT_FAIL_RSP ? "OPEN_FAIL" :
179                 flow == CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND ?
180                  "REMOTE_SHUTDOWN" : "UKNOWN CTRL COMMAND");
181 
182 
183 
184         switch (flow) {
185         case CAIF_CTRLCMD_FLOW_OFF_IND:
186                 priv->flowenabled = false;
187                 netif_stop_queue(priv->netdev);
188                 break;
189         case CAIF_CTRLCMD_DEINIT_RSP:
190                 priv->state = CAIF_DISCONNECTED;
191                 break;
192         case CAIF_CTRLCMD_INIT_FAIL_RSP:
193                 priv->state = CAIF_DISCONNECTED;
194                 wake_up_interruptible(&priv->netmgmt_wq);
195                 break;
196         case CAIF_CTRLCMD_REMOTE_SHUTDOWN_IND:
197                 priv->state = CAIF_SHUTDOWN;
198                 netif_tx_disable(priv->netdev);
199                 schedule_work(&close_worker);
200                 break;
201         case CAIF_CTRLCMD_FLOW_ON_IND:
202                 priv->flowenabled = true;
203                 netif_wake_queue(priv->netdev);
204                 break;
205         case CAIF_CTRLCMD_INIT_RSP:
206                 caif_client_register_refcnt(&priv->chnl, chnl_hold, chnl_put);
207                 priv->state = CAIF_CONNECTED;
208                 priv->flowenabled = true;
209                 netif_wake_queue(priv->netdev);
210                 wake_up_interruptible(&priv->netmgmt_wq);
211                 break;
212         default:
213                 break;
214         }
215 }
216 
217 static int chnl_net_start_xmit(struct sk_buff *skb, struct net_device *dev)
218 {
219         struct chnl_net *priv;
220         struct cfpkt *pkt = NULL;
221         int len;
222         int result = -1;
223         /* Get our private data. */
224         priv = netdev_priv(dev);
225 
226         if (skb->len > priv->netdev->mtu) {
227                 pr_warn("Size of skb exceeded MTU\n");
228                 kfree_skb(skb);
229                 dev->stats.tx_errors++;
230                 return NETDEV_TX_OK;
231         }
232 
233         if (!priv->flowenabled) {
234                 pr_debug("dropping packets flow off\n");
235                 kfree_skb(skb);
236                 dev->stats.tx_dropped++;
237                 return NETDEV_TX_OK;
238         }
239 
240         if (priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP)
241                 swap(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr);
242 
243         /* Store original SKB length. */
244         len = skb->len;
245 
246         pkt = cfpkt_fromnative(CAIF_DIR_OUT, (void *) skb);
247 
248         /* Send the packet down the stack. */
249         result = priv->chnl.dn->transmit(priv->chnl.dn, pkt);
250         if (result) {
251                 dev->stats.tx_dropped++;
252                 return NETDEV_TX_OK;
253         }
254 
255         /* Update statistics. */
256         dev->stats.tx_packets++;
257         dev->stats.tx_bytes += len;
258 
259         return NETDEV_TX_OK;
260 }
261 
262 static int chnl_net_open(struct net_device *dev)
263 {
264         struct chnl_net *priv = NULL;
265         int result = -1;
266         int llifindex, headroom, tailroom, mtu;
267         struct net_device *lldev;
268         ASSERT_RTNL();
269         priv = netdev_priv(dev);
270         if (!priv) {
271                 pr_debug("chnl_net_open: no priv\n");
272                 return -ENODEV;
273         }
274 
275         if (priv->state != CAIF_CONNECTING) {
276                 priv->state = CAIF_CONNECTING;
277                 result = caif_connect_client(dev_net(dev), &priv->conn_req,
278                                                 &priv->chnl, &llifindex,
279                                                 &headroom, &tailroom);
280                 if (result != 0) {
281                                 pr_debug("err: "
282                                          "Unable to register and open device,"
283                                          " Err:%d\n",
284                                          result);
285                                 goto error;
286                 }
287 
288                 lldev = __dev_get_by_index(dev_net(dev), llifindex);
289 
290                 if (lldev == NULL) {
291                         pr_debug("no interface?\n");
292                         result = -ENODEV;
293                         goto error;
294                 }
295 
296                 dev->needed_tailroom = tailroom + lldev->needed_tailroom;
297                 dev->hard_header_len = headroom + lldev->hard_header_len +
298                         lldev->needed_tailroom;
299 
300                 /*
301                  * MTU, head-room etc is not know before we have a
302                  * CAIF link layer device available. MTU calculation may
303                  * override initial RTNL configuration.
304                  * MTU is minimum of current mtu, link layer mtu pluss
305                  * CAIF head and tail, and PDP GPRS contexts max MTU.
306                  */
307                 mtu = min_t(int, dev->mtu, lldev->mtu - (headroom + tailroom));
308                 mtu = min_t(int, GPRS_PDP_MTU, mtu);
309                 dev_set_mtu(dev, mtu);
310 
311                 if (mtu < 100) {
312                         pr_warn("CAIF Interface MTU too small (%d)\n", mtu);
313                         result = -ENODEV;
314                         goto error;
315                 }
316         }
317 
318         rtnl_unlock();  /* Release RTNL lock during connect wait */
319 
320         result = wait_event_interruptible_timeout(priv->netmgmt_wq,
321                                                 priv->state != CAIF_CONNECTING,
322                                                 CONNECT_TIMEOUT);
323 
324         rtnl_lock();
325 
326         if (result == -ERESTARTSYS) {
327                 pr_debug("wait_event_interruptible woken by a signal\n");
328                 result = -ERESTARTSYS;
329                 goto error;
330         }
331 
332         if (result == 0) {
333                 pr_debug("connect timeout\n");
334                 caif_disconnect_client(dev_net(dev), &priv->chnl);
335                 priv->state = CAIF_DISCONNECTED;
336                 pr_debug("state disconnected\n");
337                 result = -ETIMEDOUT;
338                 goto error;
339         }
340 
341         if (priv->state != CAIF_CONNECTED) {
342                 pr_debug("connect failed\n");
343                 result = -ECONNREFUSED;
344                 goto error;
345         }
346         pr_debug("CAIF Netdevice connected\n");
347         return 0;
348 
349 error:
350         caif_disconnect_client(dev_net(dev), &priv->chnl);
351         priv->state = CAIF_DISCONNECTED;
352         pr_debug("state disconnected\n");
353         return result;
354 
355 }
356 
357 static int chnl_net_stop(struct net_device *dev)
358 {
359         struct chnl_net *priv;
360 
361         ASSERT_RTNL();
362         priv = netdev_priv(dev);
363         priv->state = CAIF_DISCONNECTED;
364         caif_disconnect_client(dev_net(dev), &priv->chnl);
365         return 0;
366 }
367 
368 static int chnl_net_init(struct net_device *dev)
369 {
370         struct chnl_net *priv;
371         ASSERT_RTNL();
372         priv = netdev_priv(dev);
373         strncpy(priv->name, dev->name, sizeof(priv->name));
374         return 0;
375 }
376 
377 static void chnl_net_uninit(struct net_device *dev)
378 {
379         struct chnl_net *priv;
380         ASSERT_RTNL();
381         priv = netdev_priv(dev);
382         robust_list_del(&priv->list_field);
383 }
384 
385 static const struct net_device_ops netdev_ops = {
386         .ndo_open = chnl_net_open,
387         .ndo_stop = chnl_net_stop,
388         .ndo_init = chnl_net_init,
389         .ndo_uninit = chnl_net_uninit,
390         .ndo_start_xmit = chnl_net_start_xmit,
391 };
392 
393 static void chnl_net_destructor(struct net_device *dev)
394 {
395         struct chnl_net *priv = netdev_priv(dev);
396         caif_free_client(&priv->chnl);
397         free_netdev(dev);
398 }
399 
400 static void ipcaif_net_setup(struct net_device *dev)
401 {
402         struct chnl_net *priv;
403         dev->netdev_ops = &netdev_ops;
404         dev->destructor = chnl_net_destructor;
405         dev->flags |= IFF_NOARP;
406         dev->flags |= IFF_POINTOPOINT;
407         dev->mtu = GPRS_PDP_MTU;
408         dev->tx_queue_len = CAIF_NET_DEFAULT_QUEUE_LEN;
409 
410         priv = netdev_priv(dev);
411         priv->chnl.receive = chnl_recv_cb;
412         priv->chnl.ctrlcmd = chnl_flowctrl_cb;
413         priv->netdev = dev;
414         priv->conn_req.protocol = CAIFPROTO_DATAGRAM;
415         priv->conn_req.link_selector = CAIF_LINK_HIGH_BANDW;
416         priv->conn_req.priority = CAIF_PRIO_LOW;
417         /* Insert illegal value */
418         priv->conn_req.sockaddr.u.dgm.connection_id = UNDEF_CONNID;
419         priv->flowenabled = false;
420 
421         init_waitqueue_head(&priv->netmgmt_wq);
422 }
423 
424 
425 static int ipcaif_fill_info(struct sk_buff *skb, const struct net_device *dev)
426 {
427         struct chnl_net *priv;
428         u8 loop;
429         priv = netdev_priv(dev);
430         if (nla_put_u32(skb, IFLA_CAIF_IPV4_CONNID,
431                         priv->conn_req.sockaddr.u.dgm.connection_id) ||
432             nla_put_u32(skb, IFLA_CAIF_IPV6_CONNID,
433                         priv->conn_req.sockaddr.u.dgm.connection_id))
434                 goto nla_put_failure;
435         loop = priv->conn_req.protocol == CAIFPROTO_DATAGRAM_LOOP;
436         if (nla_put_u8(skb, IFLA_CAIF_LOOPBACK, loop))
437                 goto nla_put_failure;
438         return 0;
439 nla_put_failure:
440         return -EMSGSIZE;
441 
442 }
443 
444 static void caif_netlink_parms(struct nlattr *data[],
445                                struct caif_connect_request *conn_req)
446 {
447         if (!data) {
448                 pr_warn("no params data found\n");
449                 return;
450         }
451         if (data[IFLA_CAIF_IPV4_CONNID])
452                 conn_req->sockaddr.u.dgm.connection_id =
453                         nla_get_u32(data[IFLA_CAIF_IPV4_CONNID]);
454         if (data[IFLA_CAIF_IPV6_CONNID])
455                 conn_req->sockaddr.u.dgm.connection_id =
456                         nla_get_u32(data[IFLA_CAIF_IPV6_CONNID]);
457         if (data[IFLA_CAIF_LOOPBACK]) {
458                 if (nla_get_u8(data[IFLA_CAIF_LOOPBACK]))
459                         conn_req->protocol = CAIFPROTO_DATAGRAM_LOOP;
460                 else
461                         conn_req->protocol = CAIFPROTO_DATAGRAM;
462         }
463 }
464 
465 static int ipcaif_newlink(struct net *src_net, struct net_device *dev,
466                           struct nlattr *tb[], struct nlattr *data[])
467 {
468         int ret;
469         struct chnl_net *caifdev;
470         ASSERT_RTNL();
471         caifdev = netdev_priv(dev);
472         caif_netlink_parms(data, &caifdev->conn_req);
473 
474         ret = register_netdevice(dev);
475         if (ret)
476                 pr_warn("device rtml registration failed\n");
477         else
478                 list_add(&caifdev->list_field, &chnl_net_list);
479 
480         /* Use ifindex as connection id, and use loopback channel default. */
481         if (caifdev->conn_req.sockaddr.u.dgm.connection_id == UNDEF_CONNID) {
482                 caifdev->conn_req.sockaddr.u.dgm.connection_id = dev->ifindex;
483                 caifdev->conn_req.protocol = CAIFPROTO_DATAGRAM_LOOP;
484         }
485         return ret;
486 }
487 
488 static int ipcaif_changelink(struct net_device *dev, struct nlattr *tb[],
489                              struct nlattr *data[])
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);
553 

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