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Diffstat (limited to 'drivers/char/n_hdlc.c')
-rw-r--r--drivers/char/n_hdlc.c97
1 files changed, 72 insertions, 25 deletions
diff --git a/drivers/char/n_hdlc.c b/drivers/char/n_hdlc.c
index 7251a4e05..0717fa418 100644
--- a/drivers/char/n_hdlc.c
+++ b/drivers/char/n_hdlc.c
@@ -9,7 +9,7 @@
* Al Longyear <longyear@netcom.com>, Paul Mackerras <Paul.Mackerras@cs.anu.edu.au>
*
* Original release 01/11/99
- * ==FILEDATE 19990524==
+ * ==FILEDATE 19990901==
*
* This code is released under the GNU General Public License (GPL)
*
@@ -21,8 +21,13 @@
* 1. tty write calls represent one complete transmit frame of data
* The device driver should accept the complete frame or none of
* the frame (busy) in the write method. Each write call should have
- * a byte count in the range of 2-4096 bytes (2 is min HDLC frame
- * with 1 addr byte and 1 ctrl byte).
+ * a byte count in the range of 2-65535 bytes (2 is min HDLC frame
+ * with 1 addr byte and 1 ctrl byte). The max byte count of 65535
+ * should include any crc bytes required. For example, when using
+ * CCITT CRC32, 4 crc bytes are required, so the maximum size frame
+ * the application may transmit is limited to 65531 bytes. For CCITT
+ * CRC16, the maximum application frame size would be 65533.
+ *
*
* 2. receive callbacks from the device driver represents
* one received frame. The device driver should bypass
@@ -73,7 +78,7 @@
*/
#define HDLC_MAGIC 0x239e
-#define HDLC_VERSION "1.2"
+#define HDLC_VERSION "1.11"
#include <linux/version.h>
#include <linux/config.h>
@@ -100,6 +105,7 @@
#include <linux/malloc.h>
#include <linux/tty.h>
#include <linux/errno.h>
+#include <linux/sched.h> /* to get the struct task_struct */
#include <linux/string.h> /* used in new tty drivers */
#include <linux/signal.h> /* used in new tty drivers */
#include <asm/system.h>
@@ -113,6 +119,13 @@
#include <linux/kerneld.h>
#endif
+#if LINUX_VERSION_CODE < VERSION(2,3,0)
+typedef struct wait_queue *wait_queue_head_t;
+#define DECLARE_WAITQUEUE(name,task) struct wait_queue (name) = {(task),NULL}
+#define init_waitqueue_head(head) *(head) = NULL
+#define set_current_state(a) current->state = (a)
+#endif
+
#if LINUX_VERSION_CODE >= VERSION(2,1,4)
#include <asm/segment.h>
#define GET_USER(error,value,addr) error = get_user(value,addr)
@@ -189,18 +202,21 @@ typedef size_t rw_count_t;
/*
* Buffers for individual HDLC frames
*/
-#define MAX_HDLC_FRAME_SIZE 4096
+#define MAX_HDLC_FRAME_SIZE 65535
#define DEFAULT_RX_BUF_COUNT 10
-#define MAX_RX_BUF_COUNT 30
+#define MAX_RX_BUF_COUNT 60
#define DEFAULT_TX_BUF_COUNT 1
+
typedef struct _n_hdlc_buf
{
struct _n_hdlc_buf *link;
int count;
- char buf[MAX_HDLC_FRAME_SIZE];
+ char buf[1];
} N_HDLC_BUF;
+#define N_HDLC_BUF_SIZE (sizeof(N_HDLC_BUF)+maxframe)
+
typedef struct _n_hdlc_buf_list
{
N_HDLC_BUF *head;
@@ -246,12 +262,16 @@ static struct n_hdlc *n_hdlc_alloc (void);
#if LINUX_VERSION_CODE >= VERSION(2,1,19)
MODULE_PARM(debuglevel, "i");
+MODULE_PARM(maxframe, "i");
#endif
/* debug level can be set by insmod for debugging purposes */
#define DEBUG_LEVEL_INFO 1
int debuglevel=0;
+/* max frame size for memory allocations */
+ssize_t maxframe=4096;
+
/* TTY callbacks */
static rw_ret_t n_hdlc_tty_read(struct tty_struct *,
@@ -353,6 +373,9 @@ static void n_hdlc_tty_close(struct tty_struct *tty)
printk (KERN_WARNING"n_hdlc: trying to close unopened tty!\n");
return;
}
+#if defined(TTY_NO_WRITE_SPLIT)
+ clear_bit(TTY_NO_WRITE_SPLIT,&tty->flags);
+#endif
tty->disc_data = NULL;
if (tty == n_hdlc->backup_tty)
n_hdlc->backup_tty = 0;
@@ -383,7 +406,9 @@ static int n_hdlc_tty_open (struct tty_struct *tty)
struct n_hdlc *n_hdlc = tty2n_hdlc (tty);
if (debuglevel >= DEBUG_LEVEL_INFO)
- printk("%s(%d)n_hdlc_tty_open() called\n",__FILE__,__LINE__);
+ printk("%s(%d)n_hdlc_tty_open() called (major=%u,minor=%u)\n",
+ __FILE__,__LINE__,
+ MAJOR(tty->device), MINOR(tty->device));
/* There should not be an existing table for this slot. */
if (n_hdlc) {
@@ -399,9 +424,14 @@ static int n_hdlc_tty_open (struct tty_struct *tty)
tty->disc_data = n_hdlc;
n_hdlc->tty = tty;
-
+
MOD_INC_USE_COUNT;
+#if defined(TTY_NO_WRITE_SPLIT)
+ /* change tty_io write() to not split large writes into 8K chunks */
+ set_bit(TTY_NO_WRITE_SPLIT,&tty->flags);
+#endif
+
/* Flush any pending characters in the driver and discipline. */
if (tty->ldisc.flush_buffer)
@@ -597,18 +627,26 @@ static void n_hdlc_tty_receive(struct tty_struct *tty,
return;
}
+ if ( count>maxframe ) {
+ if (debuglevel >= DEBUG_LEVEL_INFO)
+ printk("%s(%d) rx count>maxframesize, data discarded\n",
+ __FILE__,__LINE__);
+ return;
+ }
+
/* get a free HDLC buffer */
buf = n_hdlc_buf_get(&n_hdlc->rx_free_buf_list);
if (!buf) {
/* no buffers in free list, attempt to allocate another rx buffer */
/* unless the maximum count has been reached */
if (n_hdlc->rx_buf_list.count < MAX_RX_BUF_COUNT)
- buf = (N_HDLC_BUF*)kmalloc(sizeof(N_HDLC_BUF),GFP_ATOMIC);
+ buf = (N_HDLC_BUF*)kmalloc(N_HDLC_BUF_SIZE,GFP_ATOMIC);
}
if (!buf) {
- printk("%s(%d) no more rx buffers, data discarded\n",
- __FILE__,__LINE__);
+ if (debuglevel >= DEBUG_LEVEL_INFO)
+ printk("%s(%d) no more rx buffers, data discarded\n",
+ __FILE__,__LINE__);
return;
}
@@ -622,7 +660,7 @@ static void n_hdlc_tty_receive(struct tty_struct *tty,
/* wake up any blocked reads and perform async signalling */
wake_up_interruptible (&n_hdlc->read_wait);
if (n_hdlc->tty->fasync != NULL)
- kill_fasync (n_hdlc->tty->fasync, SIGIO);
+ kill_fasync (n_hdlc->tty->fasync, SIGIO, POLL_IN);
} /* end of n_hdlc_tty_receive() */
@@ -678,12 +716,11 @@ static rw_ret_t n_hdlc_tty_read (struct tty_struct *tty,
if (file->f_flags & O_NONBLOCK)
return -EAGAIN;
- /* TODO: no timeout? current->timeout = 0;*/
interruptible_sleep_on (&n_hdlc->read_wait);
if (signal_pending(current))
return -EINTR;
}
-
+
if (rbuf->count > nr) {
/* frame too large for caller's buffer (discard frame) */
ret = (rw_ret_t)-EOVERFLOW;
@@ -739,13 +776,13 @@ static rw_ret_t n_hdlc_tty_write (struct tty_struct *tty, struct file *file,
return -EIO;
/* verify frame size */
- if (count > MAX_HDLC_FRAME_SIZE) {
+ if (count > maxframe ) {
if (debuglevel & DEBUG_LEVEL_INFO)
printk (KERN_WARNING
"n_hdlc_tty_write: truncating user packet "
"from %lu to %d\n", (unsigned long) count,
- MAX_HDLC_FRAME_SIZE);
- count = MAX_HDLC_FRAME_SIZE;
+ maxframe );
+ count = maxframe;
}
/* Allocate transmit buffer */
@@ -754,8 +791,7 @@ static rw_ret_t n_hdlc_tty_write (struct tty_struct *tty, struct file *file,
/* sleep until transmit buffer available */
add_wait_queue(&n_hdlc->write_wait, &wait);
while (!tbuf) {
- /* TODO: no timeout? current->timeout = 0;*/
- current->state = TASK_INTERRUPTIBLE;
+ set_current_state(TASK_INTERRUPTIBLE);
schedule();
n_hdlc = tty2n_hdlc (tty);
@@ -773,7 +809,7 @@ static rw_ret_t n_hdlc_tty_write (struct tty_struct *tty, struct file *file,
tbuf = n_hdlc_buf_get(&n_hdlc->tx_free_buf_list);
}
- current->state = TASK_RUNNING;
+ set_current_state(TASK_RUNNING);
remove_wait_queue(&n_hdlc->write_wait, &wait);
}
@@ -1000,16 +1036,20 @@ static struct n_hdlc *n_hdlc_alloc (void)
/* allocate free rx buffer list */
for(i=0;i<DEFAULT_RX_BUF_COUNT;i++) {
- buf = (N_HDLC_BUF*)kmalloc(sizeof(N_HDLC_BUF),GFP_KERNEL);
+ buf = (N_HDLC_BUF*)kmalloc(N_HDLC_BUF_SIZE,GFP_KERNEL);
if (buf)
n_hdlc_buf_put(&n_hdlc->rx_free_buf_list,buf);
+ else if (debuglevel >= DEBUG_LEVEL_INFO)
+ printk("%s(%d)n_hdlc_alloc(), kalloc() failed for rx buffer %d\n",__FILE__,__LINE__, i);
}
- /* allocate free rx buffer list */
+ /* allocate free tx buffer list */
for(i=0;i<DEFAULT_TX_BUF_COUNT;i++) {
- buf = (N_HDLC_BUF*)kmalloc(sizeof(N_HDLC_BUF),GFP_KERNEL);
+ buf = (N_HDLC_BUF*)kmalloc(N_HDLC_BUF_SIZE,GFP_KERNEL);
if (buf)
n_hdlc_buf_put(&n_hdlc->tx_free_buf_list,buf);
+ else if (debuglevel >= DEBUG_LEVEL_INFO)
+ printk("%s(%d)n_hdlc_alloc(), kalloc() failed for tx buffer %d\n",__FILE__,__LINE__, i);
}
/* Initialize the control block */
@@ -1108,7 +1148,14 @@ int init_module(void)
static struct tty_ldisc n_hdlc_ldisc;
int status;
- printk("HDLC line discipline: version %s\n", szVersion);
+ /* range check maxframe arg */
+ if ( maxframe<4096)
+ maxframe=4096;
+ else if ( maxframe>65535)
+ maxframe=65535;
+
+ printk("HDLC line discipline: version %s, maxframe=%u\n",
+ szVersion, maxframe);
/* Register the tty discipline */
generated by cgit v1.2.3 (git 2.25.1) at 2024-09-20 18:32:53 +0000