--- /dev/null
+/*
+ * Copyright: (c) 2012 Czech Technical University in Prague
+ *
+ * Authors:
+ * Radek Matějka <radek.matejka@gmail.com>
+ * Michal Sojka <sojkam1@fel.cvut.cz>
+ *
+ * Funded by: Volkswagen Group Research
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/kthread.h>
+#include <linux/file.h>
+#include <net/sock.h>
+#include <linux/can.h>
+#include <linux/miscdevice.h>
+#include <linux/can/canethgw.h>
+
+MODULE_LICENSE("GPL");
+
+enum msg_types {
+ CAN_FRAME,
+};
+
+struct cegw_job
+{
+ struct kref refcount;
+ struct socket* can_sock;
+ struct socket* udp_sock;
+ u32 udp_dstcnt;
+ u32 udp_addrlen;
+ u8 udp_dst[0];
+};
+
+static int cegw_udp2can(void *data);
+static int cegw_udp_send(struct socket *udp_sock, struct can_frame *cf,
+ struct sockaddr* addr, int addrlen);
+static int cegw_can2udp(void *data);
+static int cegw_can_send(struct socket *can_sock, struct can_frame *cf);
+static int cegw_thread_start(void *data);
+static int cegw_thread_stop(struct cegw_job *job);
+static void cegw_job_release(struct kref *ref);
+
+static int cegw_udp_send(struct socket *udp_sock, struct can_frame *cf, struct sockaddr *addr,
+ int addrlen)
+{
+ struct msghdr mh;
+ struct kvec vec[2];
+ int err;
+ __u16 type = CAN_FRAME;
+
+ mh.msg_name = addr;
+ mh.msg_namelen = addrlen;
+ mh.msg_control = NULL;
+ mh.msg_controllen = 0;
+ mh.msg_flags = 0;
+
+ type = cpu_to_be16(type);
+ vec[0].iov_base = &type;
+ vec[0].iov_len = sizeof(type);
+ vec[1].iov_base = cf;
+ vec[1].iov_len = sizeof(*cf);
+
+ err = kernel_sendmsg(udp_sock, &mh, vec, 2, sizeof(type)+sizeof(*cf));
+
+ return err;
+}
+
+static int cegw_can_send(struct socket* can_sock, struct can_frame* cf)
+{
+ struct msghdr mh;
+ struct kvec vec;
+ int err;
+
+ mh.msg_name = NULL;
+ mh.msg_namelen = 0;
+ mh.msg_control = NULL;
+ mh.msg_controllen = 0;
+ mh.msg_flags = 0;
+
+ vec.iov_base = cf;
+ vec.iov_len = sizeof(*cf);
+
+ err = kernel_sendmsg(can_sock, &mh, &vec, 1, sizeof(*cf));
+
+ return err;
+}
+
+/**
+ * cegw_udp2can - performs udp->can routing
+ *
+ * This function is run as a thread.
+ */
+static int cegw_udp2can(void *data)
+{
+ struct can_frame cf;
+ struct kvec vec[2];
+ struct msghdr mh;
+ struct cegw_job *job = (struct cegw_job *)data;
+ struct socket *udp_sock = NULL, *can_sock = NULL;
+ int ret = 0;
+ __u16 type;
+
+ memset(&mh, 0, sizeof(mh));
+ udp_sock = job->udp_sock;
+ can_sock = job->can_sock;
+
+ while (1) {
+ vec[0].iov_base = &type;
+ vec[0].iov_len = sizeof(type);
+ vec[1].iov_base = &cf;
+ vec[1].iov_len = sizeof(cf);
+ ret = kernel_recvmsg(udp_sock, &mh, vec, 2,
+ sizeof(type) + sizeof(cf), 0);
+ if (ret == 0)
+ break;
+ if (ret != sizeof(type) + sizeof(cf)) {
+ pr_notice_ratelimited("canethgw: UDP length mismatch\n");
+ continue;
+ }
+
+ type = be16_to_cpu(type);
+ switch (type) {
+ case CAN_FRAME:
+ cf.can_id = be32_to_cpu(cf.can_id);
+ cegw_can_send(can_sock, &cf);
+ break;
+ default:
+ pr_notice_ratelimited("canethgw: Unknown message type\n");
+ }
+ }
+
+ cegw_thread_stop(job);
+ kref_put(&job->refcount, cegw_job_release);
+ do_exit(ret);
+}
+
+/**
+ * cegw_can2udp - performs can->udp routing
+ *
+ * This function is run as a thread.
+ */
+static int cegw_can2udp(void* data)
+{
+ struct msghdr mh;
+ struct kvec vec;
+ struct sockaddr *udst;
+ struct can_frame cf;
+ struct cegw_job* job = (struct cegw_job*)data;
+ struct socket* udp_sock = job->udp_sock;
+ struct socket* can_sock = job->can_sock;
+ int i;
+ int ret;
+
+ memset(&mh, 0, sizeof(mh));
+
+ while (1) {
+ vec.iov_base = &cf;
+ vec.iov_len = sizeof(cf);
+
+ ret = kernel_recvmsg(can_sock, &mh, &vec, 1,
+ sizeof(cf), 0);
+ if (ret != sizeof(cf))
+ break;
+
+ cf.can_id = cpu_to_be32(cf.can_id);
+ for (i=0; i<job->udp_dstcnt; i++) {
+ udst = (struct sockaddr *)(job->udp_dst + i*job->udp_addrlen);
+ cegw_udp_send(udp_sock, &cf, udst, job->udp_addrlen);
+ }
+ }
+
+ cegw_thread_stop(job);
+ kref_put(&job->refcount, cegw_job_release);
+ do_exit(ret);
+}
+
+static void cegw_job_release(struct kref *ref)
+{
+ struct cegw_job *job = container_of(ref, struct cegw_job, refcount);
+
+ fput(job->can_sock->file);
+ fput(job->udp_sock->file);
+ kfree(job);
+}
+
+/**
+ * cegw_thread_start - start working threads
+ * @data: (struct cegw_job *) with sockets and udp addresses filled in
+ *
+ * Two threads are started. One is serving udp->can routing and the other
+ * can->udp.
+ */
+static int cegw_thread_start(void *data)
+{
+ struct task_struct *task = NULL;
+ struct cegw_job *job = (struct cegw_job *)data;
+
+ kref_get(&job->refcount);
+ task = kthread_run(cegw_udp2can, data, "canethgw_udp2can");
+ if (IS_ERR(task)) {
+ kref_put(&job->refcount, cegw_job_release);
+ return -ENOMEM;
+ }
+
+ kref_get(&job->refcount);
+ task = kthread_run(cegw_can2udp, data, "canethgw_can2udp");
+ if (IS_ERR(task)) {
+ cegw_thread_stop(job);
+ kref_put(&job->refcount, cegw_job_release);
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+/**
+ * cegw_thread_stop - stops threads
+ */
+static int cegw_thread_stop(struct cegw_job *job)
+{
+ int how = SHUT_RDWR;
+ struct sock *sk = NULL;
+ struct socket *udp_sock = job->udp_sock;
+ struct socket *can_sock = job->can_sock;
+
+ if (udp_sock)
+ kernel_sock_shutdown(udp_sock, SHUT_RDWR);
+
+ /* PF_CAN sockets do not implement shutdown - do it manualy */
+ sk = can_sock->sk;
+ how++;
+ lock_sock(sk);
+ sk->sk_shutdown |= how;
+ sk->sk_state_change(sk);
+ release_sock(sk);
+
+ return 0;
+}
+
+static int cegw_open(struct inode *inode, struct file *file)
+{
+ file->private_data = NULL;
+
+ if (try_module_get(THIS_MODULE) == false)
+ return -EAGAIN;
+
+ return 0;
+}
+
+static int cegw_release(struct inode *inode, struct file *file)
+{
+ struct cegw_job *job = (struct cegw_job *)file->private_data;
+
+ if (job) {
+ cegw_thread_stop(job);
+ }
+ kref_put(&job->refcount, cegw_job_release);
+
+ module_put(THIS_MODULE);
+ return 0;
+}
+
+/**
+ * cegw_ioctl_start - processes ioctl CEGW_IOCTL_START call
+ *
+ * The function takes over cegw_ioctl structure from userspace and
+ * prepares cegw_job structure. The cegw_job is stored in
+ * file->private_data and used by kernel threads to serve gateway
+ * functionality.
+ */
+static long cegw_ioctl_start(struct file *file, unsigned long arg)
+{
+ int i;
+ int chckfam;
+ int err = 0;
+ __u32 dstcnt = 0;
+ __u32 addrlen = 0;
+ struct sockaddr *sa;
+ struct cegw_ioctl gwctl;
+ struct cegw_job *job = NULL;
+
+ err = copy_from_user(&gwctl, (void __user *)arg, sizeof(gwctl));
+ if (err != 0)
+ return -EFAULT;
+
+ dstcnt = gwctl.udp_dstcnt;
+ addrlen = gwctl.udp_addrlen;
+
+ if (addrlen != sizeof(struct sockaddr_in) && addrlen != sizeof(struct sockaddr_in6))
+ return -EAFNOSUPPORT;
+
+ /* ToDo: consider dstcnt maximum */
+ job = kmalloc(GFP_KERNEL, sizeof(*job) + dstcnt*addrlen);
+ if (job == NULL)
+ return -ENOMEM;
+
+ err = copy_from_user(&job->udp_dst, (void __user *)(arg + sizeof(struct cegw_ioctl)), dstcnt*addrlen);
+ if (err != 0) {
+ err = -EFAULT;
+ goto err_free;
+ }
+
+ /* */
+ if (dstcnt > 0)
+ sa = (struct sockaddr *)job->udp_dst;
+ chckfam = sa->sa_family;
+
+ for (i=1; i<dstcnt; i++) {
+ sa = (struct sockaddr *)(job->udp_dst + i*addrlen);
+ if (sa->sa_family != chckfam) {
+ err = -EAFNOSUPPORT;
+ goto err_free;
+ }
+ }
+
+ job->udp_sock = sockfd_lookup(gwctl.udp_sock, &err);
+ if (job->udp_sock == NULL)
+ goto err_free;
+
+ job->can_sock = sockfd_lookup(gwctl.can_sock, &err);
+ if (job->can_sock == NULL)
+ goto err_put_udp;
+
+ if (job->can_sock->ops->family != AF_CAN ||
+ job->can_sock->type != SOCK_RAW) {
+ err = -EBADF;
+ goto err_put_all;
+ }
+
+ kref_init(&job->refcount);
+
+ job->udp_dstcnt = dstcnt;
+ job->udp_addrlen = addrlen;
+
+ err = cegw_thread_start(job);
+ if (err != 0)
+ return err; /* cegw_thread_start performs cleaup for us. */
+
+ file->private_data = job;
+ return 0;
+
+err_put_all:
+ fput(job->can_sock->file);
+err_put_udp:
+ fput(job->udp_sock->file);
+err_free:
+ kfree(job);
+ return err;
+}
+
+static long cegw_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+ long err;
+
+ switch (cmd) {
+ case CEGW_IOCTL_START:
+ err = cegw_ioctl_start(file, arg);
+ break;
+ default:
+ err = -EOPNOTSUPP;
+ break;
+ }
+
+ return err;
+}
+
+static const struct file_operations cegw_fops = {
+ .owner = THIS_MODULE,
+ .open = cegw_open,
+ .release = cegw_release,
+ .unlocked_ioctl = cegw_ioctl,
+ .compat_ioctl = cegw_ioctl,
+};
+
+static struct miscdevice cegw_device = {
+ .minor = MISC_DYNAMIC_MINOR,
+ .name = "canethgw",
+ .fops = &cegw_fops
+};
+
+static int __init cegw_init(void)
+{
+ pr_info("can: can-eth gateway\n");
+ return misc_register(&cegw_device);
+}
+
+static void __exit cegw_exit(void)
+{
+ misc_deregister(&cegw_device);
+
+ return;
+}
+
+module_init(cegw_init);
+module_exit(cegw_exit);
projects / can-eth-gw-linux.git / commitdiff