1 // SPDX-License-Identifier: GPL-2.0
2 // Copyright (c) 2010-2011 EIA Electronics,
3 // Pieter Beyens <pieter.beyens@eia.be>
4 // Copyright (c) 2010-2011 EIA Electronics,
5 // Kurt Van Dijck <kurt.van.dijck@eia.be>
6 // Copyright (c) 2018 Protonic,
7 // Robin van der Gracht <robin@protonic.nl>
8 // Copyright (c) 2017-2019 Pengutronix,
9 // Marc Kleine-Budde <kernel@pengutronix.de>
10 // Copyright (c) 2017-2019 Pengutronix,
11 // Oleksij Rempel <kernel@pengutronix.de>
13 /* Core of can-j1939 that links j1939 to CAN. */
15 #include <linux/can/can-ml.h>
16 #include <linux/can/core.h>
17 #include <linux/can/skb.h>
18 #include <linux/if_arp.h>
19 #include <linux/module.h>
21 #include "j1939-priv.h"
23 MODULE_DESCRIPTION("PF_CAN SAE J1939");
24 MODULE_LICENSE("GPL v2");
25 MODULE_AUTHOR("EIA Electronics (Kurt Van Dijck & Pieter Beyens)");
26 MODULE_ALIAS("can-proto-" __stringify(CAN_J1939));
28 /* LOWLEVEL CAN interface */
30 /* CAN_HDR: #bytes before can_frame data part */
31 #define J1939_CAN_HDR (offsetof(struct can_frame, data))
33 /* CAN_FTR: #bytes beyond data part */
34 #define J1939_CAN_FTR (sizeof(struct can_frame) - J1939_CAN_HDR - \
35 sizeof(((struct can_frame *)0)->data))
38 static void j1939_can_recv(struct sk_buff *iskb, void *data)
40 struct j1939_priv *priv = data;
42 struct j1939_sk_buff_cb *skcb, *iskcb;
45 /* make sure we only get Classical CAN frames */
46 if (!can_is_can_skb(iskb))
49 /* create a copy of the skb
50 * j1939 only delivers the real data bytes,
51 * the header goes into sockaddr.
52 * j1939 may not touch the incoming skb in such way
54 skb = skb_clone(iskb, GFP_ATOMIC);
59 can_skb_set_owner(skb, iskb->sk);
61 /* get a pointer to the header of the skb
62 * the skb payload (pointer) is moved, so that the next skb_data
63 * returns the actual payload
65 cf = (void *)skb->data;
66 skb_pull(skb, J1939_CAN_HDR);
68 /* fix length, set to dlc, with 8 maximum */
69 skb_trim(skb, min_t(uint8_t, cf->len, 8));
72 skcb = j1939_skb_to_cb(skb);
73 memset(skcb, 0, sizeof(*skcb));
75 iskcb = j1939_skb_to_cb(iskb);
76 skcb->tskey = iskcb->tskey;
77 skcb->priority = (cf->can_id >> 26) & 0x7;
78 skcb->addr.sa = cf->can_id;
79 skcb->addr.pgn = (cf->can_id >> 8) & J1939_PGN_MAX;
80 /* set default message type */
81 skcb->addr.type = J1939_TP;
83 if (!j1939_address_is_valid(skcb->addr.sa)) {
84 netdev_err_once(priv->ndev, "%s: sa is broadcast address, ignoring!\n",
89 if (j1939_pgn_is_pdu1(skcb->addr.pgn)) {
90 /* Type 1: with destination address */
91 skcb->addr.da = skcb->addr.pgn;
92 /* normalize pgn: strip dst address */
93 skcb->addr.pgn &= 0x3ff00;
95 /* set broadcast address */
96 skcb->addr.da = J1939_NO_ADDR;
99 /* update localflags */
100 read_lock_bh(&priv->lock);
101 if (j1939_address_is_unicast(skcb->addr.sa) &&
102 priv->ents[skcb->addr.sa].nusers)
103 skcb->flags |= J1939_ECU_LOCAL_SRC;
104 if (j1939_address_is_unicast(skcb->addr.da) &&
105 priv->ents[skcb->addr.da].nusers)
106 skcb->flags |= J1939_ECU_LOCAL_DST;
107 read_unlock_bh(&priv->lock);
109 /* deliver into the j1939 stack ... */
110 j1939_ac_recv(priv, skb);
112 if (j1939_tp_recv(priv, skb))
113 /* this means the transport layer processed the message */
116 j1939_simple_recv(priv, skb);
117 j1939_sk_recv(priv, skb);
119 j1939_priv_put(priv);
123 /* NETDEV MANAGEMENT */
125 /* values for can_rx_(un)register */
126 #define J1939_CAN_ID CAN_EFF_FLAG
127 #define J1939_CAN_MASK (CAN_EFF_FLAG | CAN_RTR_FLAG)
129 static DEFINE_SPINLOCK(j1939_netdev_lock);
131 static struct j1939_priv *j1939_priv_create(struct net_device *ndev)
133 struct j1939_priv *priv;
135 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
139 rwlock_init(&priv->lock);
140 INIT_LIST_HEAD(&priv->ecus);
142 kref_init(&priv->kref);
143 kref_init(&priv->rx_kref);
146 netdev_dbg(priv->ndev, "%s : 0x%p\n", __func__, priv);
151 static inline void j1939_priv_set(struct net_device *ndev,
152 struct j1939_priv *priv)
154 struct can_ml_priv *can_ml = can_get_ml_priv(ndev);
156 can_ml->j1939_priv = priv;
159 static void __j1939_priv_release(struct kref *kref)
161 struct j1939_priv *priv = container_of(kref, struct j1939_priv, kref);
162 struct net_device *ndev = priv->ndev;
164 netdev_dbg(priv->ndev, "%s: 0x%p\n", __func__, priv);
166 WARN_ON_ONCE(!list_empty(&priv->active_session_list));
167 WARN_ON_ONCE(!list_empty(&priv->ecus));
168 WARN_ON_ONCE(!list_empty(&priv->j1939_socks));
174 void j1939_priv_put(struct j1939_priv *priv)
176 kref_put(&priv->kref, __j1939_priv_release);
179 void j1939_priv_get(struct j1939_priv *priv)
181 kref_get(&priv->kref);
184 static int j1939_can_rx_register(struct j1939_priv *priv)
186 struct net_device *ndev = priv->ndev;
189 j1939_priv_get(priv);
190 ret = can_rx_register(dev_net(ndev), ndev, J1939_CAN_ID, J1939_CAN_MASK,
191 j1939_can_recv, priv, "j1939", NULL);
193 j1939_priv_put(priv);
200 static void j1939_can_rx_unregister(struct j1939_priv *priv)
202 struct net_device *ndev = priv->ndev;
204 can_rx_unregister(dev_net(ndev), ndev, J1939_CAN_ID, J1939_CAN_MASK,
205 j1939_can_recv, priv);
207 /* The last reference of priv is dropped by the RCU deferred
208 * j1939_sk_sock_destruct() of the last socket, so we can
209 * safely drop this reference here.
211 j1939_priv_put(priv);
214 static void __j1939_rx_release(struct kref *kref)
215 __releases(&j1939_netdev_lock)
217 struct j1939_priv *priv = container_of(kref, struct j1939_priv,
220 j1939_can_rx_unregister(priv);
221 j1939_ecu_unmap_all(priv);
222 j1939_priv_set(priv->ndev, NULL);
223 spin_unlock(&j1939_netdev_lock);
226 /* get pointer to priv without increasing ref counter */
227 static inline struct j1939_priv *j1939_ndev_to_priv(struct net_device *ndev)
229 struct can_ml_priv *can_ml = can_get_ml_priv(ndev);
231 return can_ml->j1939_priv;
234 static struct j1939_priv *j1939_priv_get_by_ndev_locked(struct net_device *ndev)
236 struct j1939_priv *priv;
238 lockdep_assert_held(&j1939_netdev_lock);
240 priv = j1939_ndev_to_priv(ndev);
242 j1939_priv_get(priv);
247 static struct j1939_priv *j1939_priv_get_by_ndev(struct net_device *ndev)
249 struct j1939_priv *priv;
251 spin_lock(&j1939_netdev_lock);
252 priv = j1939_priv_get_by_ndev_locked(ndev);
253 spin_unlock(&j1939_netdev_lock);
258 struct j1939_priv *j1939_netdev_start(struct net_device *ndev)
260 struct j1939_priv *priv, *priv_new;
263 spin_lock(&j1939_netdev_lock);
264 priv = j1939_priv_get_by_ndev_locked(ndev);
266 kref_get(&priv->rx_kref);
267 spin_unlock(&j1939_netdev_lock);
270 spin_unlock(&j1939_netdev_lock);
272 priv = j1939_priv_create(ndev);
274 return ERR_PTR(-ENOMEM);
277 spin_lock_init(&priv->j1939_socks_lock);
278 INIT_LIST_HEAD(&priv->j1939_socks);
280 spin_lock(&j1939_netdev_lock);
281 priv_new = j1939_priv_get_by_ndev_locked(ndev);
283 /* Someone was faster than us, use their priv and roll
286 kref_get(&priv_new->rx_kref);
287 spin_unlock(&j1939_netdev_lock);
292 j1939_priv_set(ndev, priv);
293 spin_unlock(&j1939_netdev_lock);
295 ret = j1939_can_rx_register(priv);
302 j1939_priv_set(ndev, NULL);
309 void j1939_netdev_stop(struct j1939_priv *priv)
311 kref_put_lock(&priv->rx_kref, __j1939_rx_release, &j1939_netdev_lock);
312 j1939_priv_put(priv);
315 int j1939_send_one(struct j1939_priv *priv, struct sk_buff *skb)
319 struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
320 struct can_frame *cf;
322 /* apply sanity checks */
323 if (j1939_pgn_is_pdu1(skcb->addr.pgn))
324 skcb->addr.pgn &= J1939_PGN_PDU1_MAX;
326 skcb->addr.pgn &= J1939_PGN_MAX;
328 if (skcb->priority > 7)
331 ret = j1939_ac_fixup(priv, skb);
336 /* re-claim the CAN_HDR from the SKB */
337 cf = skb_push(skb, J1939_CAN_HDR);
339 /* initialize header structure */
340 memset(cf, 0, J1939_CAN_HDR);
342 /* make it a full can frame again */
343 skb_put(skb, J1939_CAN_FTR + (8 - dlc));
345 canid = CAN_EFF_FLAG |
346 (skcb->priority << 26) |
347 (skcb->addr.pgn << 8) |
349 if (j1939_pgn_is_pdu1(skcb->addr.pgn))
350 canid |= skcb->addr.da << 8;
355 return can_send(skb, 1);
362 static int j1939_netdev_notify(struct notifier_block *nb,
363 unsigned long msg, void *data)
365 struct net_device *ndev = netdev_notifier_info_to_dev(data);
366 struct can_ml_priv *can_ml = can_get_ml_priv(ndev);
367 struct j1939_priv *priv;
372 priv = j1939_priv_get_by_ndev(ndev);
378 j1939_cancel_active_session(priv, NULL);
379 j1939_sk_netdev_event_netdown(priv);
380 j1939_ecu_unmap_all(priv);
384 j1939_priv_put(priv);
390 static struct notifier_block j1939_netdev_notifier = {
391 .notifier_call = j1939_netdev_notify,
394 /* MODULE interface */
395 static __init int j1939_module_init(void)
399 pr_info("can: SAE J1939\n");
401 ret = register_netdevice_notifier(&j1939_netdev_notifier);
405 ret = can_proto_register(&j1939_can_proto);
407 pr_err("can: registration of j1939 protocol failed\n");
414 unregister_netdevice_notifier(&j1939_netdev_notifier);
419 static __exit void j1939_module_exit(void)
421 can_proto_unregister(&j1939_can_proto);
423 unregister_netdevice_notifier(&j1939_netdev_notifier);
426 module_init(j1939_module_init);
427 module_exit(j1939_module_exit);