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 /* create a copy of the skb
46 * j1939 only delivers the real data bytes,
47 * the header goes into sockaddr.
48 * j1939 may not touch the incoming skb in such way
50 skb = skb_clone(iskb, GFP_ATOMIC);
55 can_skb_set_owner(skb, iskb->sk);
57 /* get a pointer to the header of the skb
58 * the skb payload (pointer) is moved, so that the next skb_data
59 * returns the actual payload
61 cf = (void *)skb->data;
62 skb_pull(skb, J1939_CAN_HDR);
64 /* fix length, set to dlc, with 8 maximum */
65 skb_trim(skb, min_t(uint8_t, cf->len, 8));
68 skcb = j1939_skb_to_cb(skb);
69 memset(skcb, 0, sizeof(*skcb));
71 iskcb = j1939_skb_to_cb(iskb);
72 skcb->tskey = iskcb->tskey;
73 skcb->priority = (cf->can_id >> 26) & 0x7;
74 skcb->addr.sa = cf->can_id;
75 skcb->addr.pgn = (cf->can_id >> 8) & J1939_PGN_MAX;
76 /* set default message type */
77 skcb->addr.type = J1939_TP;
78 if (j1939_pgn_is_pdu1(skcb->addr.pgn)) {
79 /* Type 1: with destination address */
80 skcb->addr.da = skcb->addr.pgn;
81 /* normalize pgn: strip dst address */
82 skcb->addr.pgn &= 0x3ff00;
84 /* set broadcast address */
85 skcb->addr.da = J1939_NO_ADDR;
88 /* update localflags */
89 read_lock_bh(&priv->lock);
90 if (j1939_address_is_unicast(skcb->addr.sa) &&
91 priv->ents[skcb->addr.sa].nusers)
92 skcb->flags |= J1939_ECU_LOCAL_SRC;
93 if (j1939_address_is_unicast(skcb->addr.da) &&
94 priv->ents[skcb->addr.da].nusers)
95 skcb->flags |= J1939_ECU_LOCAL_DST;
96 read_unlock_bh(&priv->lock);
98 /* deliver into the j1939 stack ... */
99 j1939_ac_recv(priv, skb);
101 if (j1939_tp_recv(priv, skb))
102 /* this means the transport layer processed the message */
105 j1939_simple_recv(priv, skb);
106 j1939_sk_recv(priv, skb);
108 j1939_priv_put(priv);
112 /* NETDEV MANAGEMENT */
114 /* values for can_rx_(un)register */
115 #define J1939_CAN_ID CAN_EFF_FLAG
116 #define J1939_CAN_MASK (CAN_EFF_FLAG | CAN_RTR_FLAG)
118 static DEFINE_SPINLOCK(j1939_netdev_lock);
120 static struct j1939_priv *j1939_priv_create(struct net_device *ndev)
122 struct j1939_priv *priv;
124 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
128 rwlock_init(&priv->lock);
129 INIT_LIST_HEAD(&priv->ecus);
131 kref_init(&priv->kref);
132 kref_init(&priv->rx_kref);
135 netdev_dbg(priv->ndev, "%s : 0x%p\n", __func__, priv);
140 static inline void j1939_priv_set(struct net_device *ndev,
141 struct j1939_priv *priv)
143 struct can_ml_priv *can_ml = can_get_ml_priv(ndev);
145 can_ml->j1939_priv = priv;
148 static void __j1939_priv_release(struct kref *kref)
150 struct j1939_priv *priv = container_of(kref, struct j1939_priv, kref);
151 struct net_device *ndev = priv->ndev;
153 netdev_dbg(priv->ndev, "%s: 0x%p\n", __func__, priv);
155 WARN_ON_ONCE(!list_empty(&priv->active_session_list));
156 WARN_ON_ONCE(!list_empty(&priv->ecus));
157 WARN_ON_ONCE(!list_empty(&priv->j1939_socks));
163 void j1939_priv_put(struct j1939_priv *priv)
165 kref_put(&priv->kref, __j1939_priv_release);
168 void j1939_priv_get(struct j1939_priv *priv)
170 kref_get(&priv->kref);
173 static int j1939_can_rx_register(struct j1939_priv *priv)
175 struct net_device *ndev = priv->ndev;
178 j1939_priv_get(priv);
179 ret = can_rx_register(dev_net(ndev), ndev, J1939_CAN_ID, J1939_CAN_MASK,
180 j1939_can_recv, priv, "j1939", NULL);
182 j1939_priv_put(priv);
189 static void j1939_can_rx_unregister(struct j1939_priv *priv)
191 struct net_device *ndev = priv->ndev;
193 can_rx_unregister(dev_net(ndev), ndev, J1939_CAN_ID, J1939_CAN_MASK,
194 j1939_can_recv, priv);
196 /* The last reference of priv is dropped by the RCU deferred
197 * j1939_sk_sock_destruct() of the last socket, so we can
198 * safely drop this reference here.
200 j1939_priv_put(priv);
203 static void __j1939_rx_release(struct kref *kref)
204 __releases(&j1939_netdev_lock)
206 struct j1939_priv *priv = container_of(kref, struct j1939_priv,
209 j1939_can_rx_unregister(priv);
210 j1939_ecu_unmap_all(priv);
211 j1939_priv_set(priv->ndev, NULL);
212 spin_unlock(&j1939_netdev_lock);
215 /* get pointer to priv without increasing ref counter */
216 static inline struct j1939_priv *j1939_ndev_to_priv(struct net_device *ndev)
218 struct can_ml_priv *can_ml = can_get_ml_priv(ndev);
220 return can_ml->j1939_priv;
223 static struct j1939_priv *j1939_priv_get_by_ndev_locked(struct net_device *ndev)
225 struct j1939_priv *priv;
227 lockdep_assert_held(&j1939_netdev_lock);
229 priv = j1939_ndev_to_priv(ndev);
231 j1939_priv_get(priv);
236 static struct j1939_priv *j1939_priv_get_by_ndev(struct net_device *ndev)
238 struct j1939_priv *priv;
240 spin_lock(&j1939_netdev_lock);
241 priv = j1939_priv_get_by_ndev_locked(ndev);
242 spin_unlock(&j1939_netdev_lock);
247 struct j1939_priv *j1939_netdev_start(struct net_device *ndev)
249 struct j1939_priv *priv, *priv_new;
252 spin_lock(&j1939_netdev_lock);
253 priv = j1939_priv_get_by_ndev_locked(ndev);
255 kref_get(&priv->rx_kref);
256 spin_unlock(&j1939_netdev_lock);
259 spin_unlock(&j1939_netdev_lock);
261 priv = j1939_priv_create(ndev);
263 return ERR_PTR(-ENOMEM);
266 spin_lock_init(&priv->j1939_socks_lock);
267 INIT_LIST_HEAD(&priv->j1939_socks);
269 spin_lock(&j1939_netdev_lock);
270 priv_new = j1939_priv_get_by_ndev_locked(ndev);
272 /* Someone was faster than us, use their priv and roll
275 kref_get(&priv_new->rx_kref);
276 spin_unlock(&j1939_netdev_lock);
281 j1939_priv_set(ndev, priv);
282 spin_unlock(&j1939_netdev_lock);
284 ret = j1939_can_rx_register(priv);
291 j1939_priv_set(ndev, NULL);
298 void j1939_netdev_stop(struct j1939_priv *priv)
300 kref_put_lock(&priv->rx_kref, __j1939_rx_release, &j1939_netdev_lock);
301 j1939_priv_put(priv);
304 int j1939_send_one(struct j1939_priv *priv, struct sk_buff *skb)
308 struct j1939_sk_buff_cb *skcb = j1939_skb_to_cb(skb);
309 struct can_frame *cf;
311 /* apply sanity checks */
312 if (j1939_pgn_is_pdu1(skcb->addr.pgn))
313 skcb->addr.pgn &= J1939_PGN_PDU1_MAX;
315 skcb->addr.pgn &= J1939_PGN_MAX;
317 if (skcb->priority > 7)
320 ret = j1939_ac_fixup(priv, skb);
325 /* re-claim the CAN_HDR from the SKB */
326 cf = skb_push(skb, J1939_CAN_HDR);
328 /* make it a full can frame again */
329 skb_put(skb, J1939_CAN_FTR + (8 - dlc));
331 canid = CAN_EFF_FLAG |
332 (skcb->priority << 26) |
333 (skcb->addr.pgn << 8) |
335 if (j1939_pgn_is_pdu1(skcb->addr.pgn))
336 canid |= skcb->addr.da << 8;
341 return can_send(skb, 1);
348 static int j1939_netdev_notify(struct notifier_block *nb,
349 unsigned long msg, void *data)
351 struct net_device *ndev = netdev_notifier_info_to_dev(data);
352 struct can_ml_priv *can_ml = can_get_ml_priv(ndev);
353 struct j1939_priv *priv;
358 priv = j1939_priv_get_by_ndev(ndev);
364 j1939_cancel_active_session(priv, NULL);
365 j1939_sk_netdev_event_netdown(priv);
366 j1939_ecu_unmap_all(priv);
370 j1939_priv_put(priv);
376 static struct notifier_block j1939_netdev_notifier = {
377 .notifier_call = j1939_netdev_notify,
380 /* MODULE interface */
381 static __init int j1939_module_init(void)
385 pr_info("can: SAE J1939\n");
387 ret = register_netdevice_notifier(&j1939_netdev_notifier);
391 ret = can_proto_register(&j1939_can_proto);
393 pr_err("can: registration of j1939 protocol failed\n");
400 unregister_netdevice_notifier(&j1939_netdev_notifier);
405 static __exit void j1939_module_exit(void)
407 can_proto_unregister(&j1939_can_proto);
409 unregister_netdevice_notifier(&j1939_netdev_notifier);
412 module_init(j1939_module_init);
413 module_exit(j1939_module_exit);