[PATCH net-next 2/2] tun: enable socket system calls

From: Alex Gartrell
Date: Fri Dec 26 2014 - 01:51:01 EST


By setting private_data to a socket and private_data_is_socket to true, we
can use the socket syscalls. We also can't just blindly use private_data
anymore, so there's a __tun_file_get function that returns the container_of
private_data appropriately.

Signed-off-by: Alex Gartrell <agartrell@xxxxxx>
---
drivers/net/tun.c | 34 ++++++++++++++++++++++------------
1 file changed, 22 insertions(+), 12 deletions(-)

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index a5cbf67..b16ddc5 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -547,9 +547,18 @@ static void tun_detach_all(struct net_device *dev)
module_put(THIS_MODULE);
}

+static struct tun_file *tun_file_from_file(struct file *file)
+{
+ struct socket *s = (struct socket *)file->private_data;
+
+ if (!s)
+ return NULL;
+ return container_of(s, struct tun_file, socket);
+}
+
static int tun_attach(struct tun_struct *tun, struct file *file, bool skip_filter)
{
- struct tun_file *tfile = file->private_data;
+ struct tun_file *tfile = tun_file_from_file(file);
int err;

err = security_tun_dev_attach(tfile->socket.sk, tun->security);
@@ -612,7 +621,7 @@ static struct tun_struct *__tun_get(struct tun_file *tfile)

static struct tun_struct *tun_get(struct file *file)
{
- return __tun_get(file->private_data);
+ return __tun_get(tun_file_from_file(file));
}

static void tun_put(struct tun_struct *tun)
@@ -973,7 +982,7 @@ static void tun_net_init(struct net_device *dev)
/* Poll */
static unsigned int tun_chr_poll(struct file *file, poll_table *wait)
{
- struct tun_file *tfile = file->private_data;
+ struct tun_file *tfile = tun_file_from_file(file);
struct tun_struct *tun = __tun_get(tfile);
struct sock *sk;
unsigned int mask = 0;
@@ -1235,7 +1244,7 @@ static ssize_t tun_chr_write_iter(struct kiocb *iocb, struct iov_iter *from)
{
struct file *file = iocb->ki_filp;
struct tun_struct *tun = tun_get(file);
- struct tun_file *tfile = file->private_data;
+ struct tun_file *tfile = tun_file_from_file(file);
ssize_t result;

if (!tun)
@@ -1392,7 +1401,7 @@ static ssize_t tun_do_read(struct tun_struct *tun, struct tun_file *tfile,
static ssize_t tun_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
{
struct file *file = iocb->ki_filp;
- struct tun_file *tfile = file->private_data;
+ struct tun_file *tfile = tun_file_from_file(file);
struct tun_struct *tun = __tun_get(tfile);
ssize_t len = iov_iter_count(to), ret;

@@ -1567,7 +1576,7 @@ static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
{
struct tun_struct *tun;
- struct tun_file *tfile = file->private_data;
+ struct tun_file *tfile = tun_file_from_file(file);
struct net_device *dev;
int err;

@@ -1801,7 +1810,7 @@ static void tun_set_sndbuf(struct tun_struct *tun)

static int tun_set_queue(struct file *file, struct ifreq *ifr)
{
- struct tun_file *tfile = file->private_data;
+ struct tun_file *tfile = tun_file_from_file(file);
struct tun_struct *tun;
int ret = 0;

@@ -1834,7 +1843,7 @@ unlock:
static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
unsigned long arg, int ifreq_len)
{
- struct tun_file *tfile = file->private_data;
+ struct tun_file *tfile = tun_file_from_file(file);
struct tun_struct *tun;
void __user* argp = (void __user*)arg;
struct ifreq ifr;
@@ -2122,7 +2131,7 @@ static long tun_chr_compat_ioctl(struct file *file,

static int tun_chr_fasync(int fd, struct file *file, int on)
{
- struct tun_file *tfile = file->private_data;
+ struct tun_file *tfile = tun_file_from_file(file);
int ret;

if ((ret = fasync_helper(fd, file, on, &tfile->fasync)) < 0)
@@ -2165,7 +2174,8 @@ static int tun_chr_open(struct inode *inode, struct file * file)
tfile->sk.sk_write_space = tun_sock_write_space;
tfile->sk.sk_sndbuf = INT_MAX;

- file->private_data = tfile;
+ file->private_data = &tfile->socket;
+ file->private_data_is_socket = true;
set_bit(SOCK_EXTERNALLY_ALLOCATED, &tfile->socket.flags);
INIT_LIST_HEAD(&tfile->next);

@@ -2176,7 +2186,7 @@ static int tun_chr_open(struct inode *inode, struct file * file)

static int tun_chr_close(struct inode *inode, struct file *file)
{
- struct tun_file *tfile = file->private_data;
+ struct tun_file *tfile = tun_file_from_file(file);
struct net *net = tfile->net;

tun_detach(tfile, true);
@@ -2335,7 +2345,7 @@ struct socket *tun_get_socket(struct file *file)
struct tun_file *tfile;
if (file->f_op != &tun_fops)
return ERR_PTR(-EINVAL);
- tfile = file->private_data;
+ tfile = tun_file_from_file(file);
if (!tfile)
return ERR_PTR(-EBADFD);
return &tfile->socket;
--
Alex Gartrell <agartrell@xxxxxx>

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/