2 * Copyright: (c) 2012 Czech Technical University in Prague
5 * Radek Matějka <radek.matejka@gmail.com>
6 * Michal Sojka <sojkam1@fel.cvut.cz>
8 * Funded by: Volkswagen Group Research
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version
13 * 2 of the License, or (at your option) any later version.
16 #include <linux/module.h>
17 #include <linux/kernel.h>
18 #include <linux/kthread.h>
19 #include <linux/file.h>
21 #include <linux/can.h>
22 #include <linux/miscdevice.h>
23 #include <linux/can/canethgw.h>
25 MODULE_LICENSE("GPL");
34 struct socket* can_sock;
35 struct socket* udp_sock;
41 static int cegw_udp2can(void *data);
42 static int cegw_udp_send(struct socket *udp_sock, struct can_frame *cf,
43 struct sockaddr* addr, int addrlen);
44 static int cegw_can2udp(void *data);
45 static int cegw_can_send(struct socket *can_sock, struct can_frame *cf);
46 static int cegw_thread_start(void *data);
47 static int cegw_thread_stop(struct cegw_job *job);
48 static void cegw_job_release(struct kref *ref);
50 static int cegw_udp_send(struct socket *udp_sock, struct can_frame *cf, struct sockaddr *addr,
56 __u16 type = CAN_FRAME;
59 mh.msg_namelen = addrlen;
60 mh.msg_control = NULL;
61 mh.msg_controllen = 0;
64 type = cpu_to_be16(type);
65 vec[0].iov_base = &type;
66 vec[0].iov_len = sizeof(type);
68 vec[1].iov_len = sizeof(*cf);
70 err = kernel_sendmsg(udp_sock, &mh, vec, 2, sizeof(type)+sizeof(*cf));
75 static int cegw_can_send(struct socket* can_sock, struct can_frame* cf)
83 mh.msg_control = NULL;
84 mh.msg_controllen = 0;
88 vec.iov_len = sizeof(*cf);
90 err = kernel_sendmsg(can_sock, &mh, &vec, 1, sizeof(*cf));
96 * cegw_udp2can - performs udp->can routing
98 * This function is run as a thread.
100 static int cegw_udp2can(void *data)
105 struct cegw_job *job = (struct cegw_job *)data;
106 struct socket *udp_sock = NULL, *can_sock = NULL;
110 memset(&mh, 0, sizeof(mh));
111 udp_sock = job->udp_sock;
112 can_sock = job->can_sock;
115 vec[0].iov_base = &type;
116 vec[0].iov_len = sizeof(type);
117 vec[1].iov_base = &cf;
118 vec[1].iov_len = sizeof(cf);
119 ret = kernel_recvmsg(udp_sock, &mh, vec, 2,
120 sizeof(type) + sizeof(cf), 0);
123 if (ret != sizeof(type) + sizeof(cf)) {
124 pr_notice_ratelimited("canethgw: UDP length mismatch\n");
128 type = be16_to_cpu(type);
131 cf.can_id = be32_to_cpu(cf.can_id);
132 cegw_can_send(can_sock, &cf);
135 pr_notice_ratelimited("canethgw: Unknown message type\n");
139 cegw_thread_stop(job);
140 kref_put(&job->refcount, cegw_job_release);
145 * cegw_can2udp - performs can->udp routing
147 * This function is run as a thread.
149 static int cegw_can2udp(void* data)
153 struct sockaddr *udst;
155 struct cegw_job* job = (struct cegw_job*)data;
156 struct socket* udp_sock = job->udp_sock;
157 struct socket* can_sock = job->can_sock;
161 memset(&mh, 0, sizeof(mh));
165 vec.iov_len = sizeof(cf);
167 ret = kernel_recvmsg(can_sock, &mh, &vec, 1,
169 if (ret != sizeof(cf))
172 cf.can_id = cpu_to_be32(cf.can_id);
173 for (i=0; i<job->udp_dstcnt; i++) {
174 udst = (struct sockaddr *)(job->udp_dst + i*job->udp_addrlen);
175 cegw_udp_send(udp_sock, &cf, udst, job->udp_addrlen);
179 cegw_thread_stop(job);
180 kref_put(&job->refcount, cegw_job_release);
184 static void cegw_job_release(struct kref *ref)
186 struct cegw_job *job = container_of(ref, struct cegw_job, refcount);
188 fput(job->can_sock->file);
189 fput(job->udp_sock->file);
194 * cegw_thread_start - start working threads
195 * @data: (struct cegw_job *) with sockets and udp addresses filled in
197 * Two threads are started. One is serving udp->can routing and the other
200 static int cegw_thread_start(void *data)
202 struct task_struct *task = NULL;
203 struct cegw_job *job = (struct cegw_job *)data;
205 kref_get(&job->refcount);
206 task = kthread_run(cegw_udp2can, data, "canethgw_udp2can");
208 kref_put(&job->refcount, cegw_job_release);
212 kref_get(&job->refcount);
213 task = kthread_run(cegw_can2udp, data, "canethgw_can2udp");
215 cegw_thread_stop(job);
216 kref_put(&job->refcount, cegw_job_release);
224 * cegw_thread_stop - stops threads
226 static int cegw_thread_stop(struct cegw_job *job)
229 struct sock *sk = NULL;
230 struct socket *udp_sock = job->udp_sock;
231 struct socket *can_sock = job->can_sock;
234 kernel_sock_shutdown(udp_sock, SHUT_RDWR);
236 /* PF_CAN sockets do not implement shutdown - do it manualy */
240 sk->sk_shutdown |= how;
241 sk->sk_state_change(sk);
247 static int cegw_open(struct inode *inode, struct file *file)
249 file->private_data = NULL;
251 if (try_module_get(THIS_MODULE) == false)
257 static int cegw_release(struct inode *inode, struct file *file)
259 struct cegw_job *job = (struct cegw_job *)file->private_data;
262 cegw_thread_stop(job);
264 kref_put(&job->refcount, cegw_job_release);
266 module_put(THIS_MODULE);
271 * cegw_ioctl_start - processes ioctl CEGW_IOCTL_START call
273 * The function takes over cegw_ioctl structure from userspace and
274 * prepares cegw_job structure. The cegw_job is stored in
275 * file->private_data and used by kernel threads to serve gateway
278 static long cegw_ioctl_start(struct file *file, unsigned long arg)
286 struct cegw_ioctl gwctl;
287 struct cegw_job *job = NULL;
289 err = copy_from_user(&gwctl, (void __user *)arg, sizeof(gwctl));
293 dstcnt = gwctl.udp_dstcnt;
294 addrlen = gwctl.udp_addrlen;
296 if (addrlen != sizeof(struct sockaddr_in) && addrlen != sizeof(struct sockaddr_in6))
297 return -EAFNOSUPPORT;
299 /* ToDo: consider dstcnt maximum */
300 job = kmalloc(GFP_KERNEL, sizeof(*job) + dstcnt*addrlen);
304 err = copy_from_user(&job->udp_dst, (void __user *)(arg + sizeof(struct cegw_ioctl)), dstcnt*addrlen);
312 sa = (struct sockaddr *)job->udp_dst;
313 chckfam = sa->sa_family;
315 for (i=1; i<dstcnt; i++) {
316 sa = (struct sockaddr *)(job->udp_dst + i*addrlen);
317 if (sa->sa_family != chckfam) {
323 job->udp_sock = sockfd_lookup(gwctl.udp_sock, &err);
324 if (job->udp_sock == NULL)
327 job->can_sock = sockfd_lookup(gwctl.can_sock, &err);
328 if (job->can_sock == NULL)
331 if (job->can_sock->ops->family != AF_CAN ||
332 job->can_sock->type != SOCK_RAW) {
337 kref_init(&job->refcount);
339 job->udp_dstcnt = dstcnt;
340 job->udp_addrlen = addrlen;
342 err = cegw_thread_start(job);
344 return err; /* cegw_thread_start performs cleaup for us. */
346 file->private_data = job;
350 fput(job->can_sock->file);
352 fput(job->udp_sock->file);
358 static long cegw_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
363 case CEGW_IOCTL_START:
364 err = cegw_ioctl_start(file, arg);
374 static const struct file_operations cegw_fops = {
375 .owner = THIS_MODULE,
377 .release = cegw_release,
378 .unlocked_ioctl = cegw_ioctl,
379 .compat_ioctl = cegw_ioctl,
382 static struct miscdevice cegw_device = {
383 .minor = MISC_DYNAMIC_MINOR,
388 static int __init cegw_init(void)
390 pr_info("can: can-eth gateway\n");
391 return misc_register(&cegw_device);
394 static void __exit cegw_exit(void)
396 misc_deregister(&cegw_device);
401 module_init(cegw_init);
402 module_exit(cegw_exit);