[PATCH] TUN/TAP driver readv/writev support 2.4.19-pre7

Maksim (maxk@qualcomm.com)
23 Apr 2002 12:01:58 -0700


Marcelo,

This patch adds proper support for readv/writev support in
TUN/TAP driver.
http://bluez.sourceforge.net/patches/tun-readv-writev-2.4.19-pre7.gz

Pleas apply

Thanks
Max

diff -urN /opt/kernel/linux/drivers/net/tun.c linux/drivers/net/tun.c
--- /opt/kernel/linux/drivers/net/tun.c Mon Jan 7 15:41:41 2002
+++ linux/drivers/net/tun.c Mon Apr 22 17:38:08 2002
@@ -1,6 +1,6 @@
/*
* TUN - Universal TUN/TAP device driver.
- * Copyright (C) 1999-2000 Maxim Krasnyansky <max_mk@yahoo.com>
+ * Copyright (C) 1999-2002 Maxim Krasnyansky <maxk@qualcomm.com>
*
* 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
@@ -12,7 +12,7 @@
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
- * $Id: tun.c,v 1.12 2001/03/08 03:29:27 maxk Exp $
+ * $Id: tun.c,v 1.15 2002/03/01 02:44:24 maxk Exp $
*/

/*
@@ -20,7 +20,7 @@
* Modifications for 2.3.99-pre5 kernel.
*/

-#define TUN_VER "1.4"
+#define TUN_VER "1.5"

#include <linux/config.h>
#include <linux/module.h>
@@ -181,19 +181,17 @@
}

/* Get packet from user space buffer(already verified) */
-static __inline__ ssize_t tun_get_user(struct tun_struct *tun, const
char *buf, size_t count)
+static __inline__ ssize_t tun_get_user(struct tun_struct *tun, struct
iovec *iv, size_t count)
{
struct tun_pi pi = { 0, __constant_htons(ETH_P_IP) };
- register const char *ptr = buf;
- register int len = count;
struct sk_buff *skb;
+ size_t len = count;

if (!(tun->flags & TUN_NO_PI)) {
if ((len -= sizeof(pi)) < 0)
return -EINVAL;

- copy_from_user(&pi, ptr, sizeof(pi));
- ptr += sizeof(pi);
+ memcpy_fromiovec((void *)&pi, iv, sizeof(pi));
}

if (!(skb = alloc_skb(len + 2, GFP_KERNEL))) {
@@ -202,7 +200,7 @@
}

skb_reserve(skb, 2);
- copy_from_user(skb_put(skb, len), ptr, len);
+ memcpy_fromiovec(skb_put(skb, len), iv, len);

skb->dev = &tun->dev;
switch (tun->flags & TUN_TYPE_MASK) {
@@ -226,31 +224,43 @@
return count;
}

-/* Write */
-static ssize_t tun_chr_write(struct file * file, const char * buf,
- size_t count, loff_t *pos)
+/* Writev */
+static ssize_t tun_chr_writev(struct file * file, const struct iovec
*iv,
+ unsigned long count, loff_t *pos)
{
struct tun_struct *tun = (struct tun_struct *)file->private_data;
+ unsigned long i;
+ size_t len;

if (!tun)
return -EBADFD;

DBG(KERN_INFO "%s: tun_chr_write %d\n", tun->name, count);

- if (verify_area(VERIFY_READ, buf, count))
- return -EFAULT;
+ for (i = 0, len = 0; i < count; i++) {
+ if (verify_area(VERIFY_READ, iv[i].iov_base, iv[i].iov_len))
+ return -EFAULT;
+ len += iv[i].iov_len;
+ }

- return tun_get_user(tun, buf, count);
+ return tun_get_user(tun, (struct iovec *) iv, len);
}

-/* Put packet to user space buffer(already verified) */
+/* Write */
+static ssize_t tun_chr_write(struct file * file, const char * buf,
+ size_t count, loff_t *pos)
+{
+ struct iovec iv = { (void *) buf, count };
+ return tun_chr_writev(file, &iv, 1, pos);
+}
+
+/* Put packet to the user space buffer (already verified) */
static __inline__ ssize_t tun_put_user(struct tun_struct *tun,
struct sk_buff *skb,
- char *buf, int count)
+ struct iovec *iv, int len)
{
struct tun_pi pi = { 0, skb->protocol };
- int len = count, total = 0;
- char *ptr = buf;
+ ssize_t total = 0;

if (!(tun->flags & TUN_NO_PI)) {
if ((len -= sizeof(pi)) < 0)
@@ -261,14 +271,13 @@
pi.flags |= TUN_PKT_STRIP;
}

- copy_to_user(ptr, &pi, sizeof(pi));
-
+ memcpy_toiovec(iv, (void *) &pi, sizeof(pi));
total += sizeof(pi);
- ptr += sizeof(pi);
}

- len = MIN(skb->len, len);
- copy_to_user(ptr, skb->data, len);
+ len = MIN(skb->len, len);
+
+ skb_copy_datagram_iovec(skb, 0, iv, len);
total += len;

tun->stats.tx_packets++;
@@ -277,22 +286,29 @@
return total;
}

-/* Read */
-static ssize_t tun_chr_read(struct file * file, char * buf,
- size_t count, loff_t *pos)
+/* Readv */
+static ssize_t tun_chr_readv(struct file *file, const struct iovec *iv,
+ unsigned long count, loff_t *pos)
{
struct tun_struct *tun = (struct tun_struct *)file->private_data;
DECLARE_WAITQUEUE(wait, current);
struct sk_buff *skb;
- ssize_t ret = 0;
+ ssize_t len, ret = 0;
+ unsigned long i;

if (!tun)
return -EBADFD;

DBG(KERN_INFO "%s: tun_chr_read\n", tun->name);

+ for (i = 0, len = 0; i < count; i++) {
+ if (verify_area(VERIFY_WRITE, iv[i].iov_base, iv[i].iov_len))
+ return -EFAULT;
+ len += iv[i].iov_len;
+ }
+
add_wait_queue(&tun->read_wait, &wait);
- while (count) {
+ while (len) {
current->state = TASK_INTERRUPTIBLE;

/* Read frames from the queue */
@@ -312,10 +328,7 @@
}
netif_start_queue(&tun->dev);

- if (!verify_area(VERIFY_WRITE, buf, count))
- ret = tun_put_user(tun, skb, buf, count);
- else
- ret = -EFAULT;
+ ret = tun_put_user(tun, skb, (struct iovec *) iv, len);

kfree_skb(skb);
break;
@@ -327,6 +340,14 @@
return ret;
}

+/* Read */
+static ssize_t tun_chr_read(struct file * file, char * buf,
+ size_t count, loff_t *pos)
+{
+ struct iovec iv = { buf, count };
+ return tun_chr_readv(file, &iv, 1, pos);
+}
+
static int tun_set_iff(struct file *file, struct ifreq *ifr)
{
struct tun_struct *tun;
@@ -546,7 +567,9 @@
owner: THIS_MODULE,
llseek: no_llseek,
read: tun_chr_read,
+ readv: tun_chr_readv,
write: tun_chr_write,
+ writev: tun_chr_writev,
poll: tun_chr_poll,
ioctl: tun_chr_ioctl,
open: tun_chr_open,
@@ -564,7 +587,7 @@
int __init tun_init(void)
{
printk(KERN_INFO "Universal TUN/TAP device driver %s "
- "(C)1999-2001 Maxim Krasnyansky\n", TUN_VER);
+ "(C)1999-2002 Maxim Krasnyansky\n", TUN_VER);

if (misc_register(&tun_miscdev)) {
printk(KERN_ERR "tun: Can't register misc device %d\n", TUN_MINOR);

-
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