-/*
- * 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 "canethgw.h"
-
-MODULE_LICENSE("GPL");
-
-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;
- int err;
-
- mh.msg_name = addr;
- mh.msg_namelen = addrlen;
- mh.msg_control = NULL;
- mh.msg_controllen = 0;
- mh.msg_flags = 0;
-
- vec.iov_base = cf;
- vec.iov_len = sizeof(*cf);
-
- err = kernel_sendmsg(udp_sock, &mh, &vec, 1, 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;
- struct msghdr mh;
- struct cegw_job *job = (struct cegw_job *)data;
- struct socket *udp_sock = NULL, *can_sock = NULL;
- int ret = 0;
-
- memset(&mh, 0, sizeof(mh));
- udp_sock = job->udp_sock;
- can_sock = job->can_sock;
-
- while (1) {
- vec.iov_base = &cf;
- vec.iov_len = sizeof(cf);
- ret = kernel_recvmsg(udp_sock, &mh, &vec, 1,
- sizeof(cf), 0);
- if (ret < 1)
- break;
-
- cf.can_id = be32_to_cpu(cf.can_id);
- cegw_can_send(can_sock, &cf);
- }
-
- 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 < 1)
- 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_init(&job->refcount);
- kref_get(&job->refcount);
-
- task = kthread_run(cegw_udp2can, data, "canethgw_udp2can");
- if (IS_ERR(task)) {
- kref_sub(&job->refcount, 2, cegw_job_release);
- return -ENOMEM;
- }
-
- 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;
-
- 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);
- }
-
- 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) {
- kfree(job);
- return -EFAULT;
- }
-
- /* */
- 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) {
- kfree(job);
- return -EAFNOSUPPORT;
- }
- }
-
- job->udp_sock = sockfd_lookup(gwctl.udp_sock, &err);
- if (job->udp_sock == NULL) {
- kfree(job);
- return err;
- }
-
- job->can_sock = sockfd_lookup(gwctl.can_sock, &err);
- if (job->can_sock == NULL) {
- fput(job->udp_sock->file);
- kfree(job);
- return err;
- }
-
- job->udp_dstcnt = dstcnt;
- job->udp_addrlen = addrlen;
-
- err = cegw_thread_start(job);
- if (err != 0)
- return err;
-
- file->private_data = job;
- return 0;
-}
-
-static long cegw_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
-{
- int 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
-};
-
-static struct miscdevice cegw_device = {
- .minor = MISC_DYNAMIC_MINOR,
- .name = "canethgw",
- .fops = &cegw_fops
-};
-
-static int __init cegw_init(void)
-{
- misc_register(&cegw_device);
-
- return 0;
-}
-
-static void __exit cegw_exit(void)
-{
- misc_deregister(&cegw_device);
-
- return;
-}
-
-module_init(cegw_init);
-module_exit(cegw_exit);
-