[v2,1/2] wan/hdlc_x25: make lapb params configurable
diff mbox series

Message ID 20200114140223.22446-1-ms@dev.tdt.de
State Changes Requested
Delegated to: David Miller
Headers show
Series
  • [v2,1/2] wan/hdlc_x25: make lapb params configurable
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Commit Message

Martin Schiller Jan. 14, 2020, 2:02 p.m. UTC
This enables you to configure mode (DTE/DCE), Modulo, Window, T1, T2, N2 via
sethdlc (which needs to be patched as well).

Signed-off-by: Martin Schiller <ms@dev.tdt.de>
---
 drivers/net/wan/hdlc_x25.c      | 78 ++++++++++++++++++++++++++++++++-
 include/uapi/linux/hdlc/ioctl.h |  9 ++++
 include/uapi/linux/if.h         |  1 +
 3 files changed, 86 insertions(+), 2 deletions(-)

Comments

David Miller Jan. 15, 2020, 9:43 p.m. UTC | #1
From: Martin Schiller <ms@dev.tdt.de>
Date: Tue, 14 Jan 2020 15:02:22 +0100

> This enables you to configure mode (DTE/DCE), Modulo, Window, T1, T2, N2 via
> sethdlc (which needs to be patched as well).
> 
> Signed-off-by: Martin Schiller <ms@dev.tdt.de>

I don't know how wise it is to add new ioctls to this old driver.

Also, none of these ioctls even have COMPAT handling so they will
never work from a 32-bit binary running on a 64-bit kernel for
example.

Also:

> +static struct x25_state* state(hdlc_device *hdlc)

It is always "type *func" never "type* func"

>  static int x25_open(struct net_device *dev)
>  {
>  	int result;
> +	hdlc_device *hdlc = dev_to_hdlc(dev);
> +	struct lapb_parms_struct params;
>  	static const struct lapb_register_struct cb = {

Please make this reverse christmas tree ordered.

> @@ -186,6 +217,9 @@ static struct hdlc_proto proto = {
>  
>  static int x25_ioctl(struct net_device *dev, struct ifreq *ifr)
>  {
> +	x25_hdlc_proto __user *x25_s = ifr->ifr_settings.ifs_ifsu.x25;
> +	const size_t size = sizeof(x25_hdlc_proto);
> +	x25_hdlc_proto new_settings;
>  	hdlc_device *hdlc = dev_to_hdlc(dev);
>  	int result;

Likewise.
Martin Schiller Jan. 16, 2020, 6:03 a.m. UTC | #2
On 2020-01-15 22:43, David Miller wrote:
> From: Martin Schiller <ms@dev.tdt.de>
> Date: Tue, 14 Jan 2020 15:02:22 +0100
> 
>> This enables you to configure mode (DTE/DCE), Modulo, Window, T1, T2, 
>> N2 via
>> sethdlc (which needs to be patched as well).
>> 
>> Signed-off-by: Martin Schiller <ms@dev.tdt.de>
> 
> I don't know how wise it is to add new ioctls to this old driver.

As an user of this framework I can tell you that you need to be able to
tune this parameters if it's used in an professional environment.

> 
> Also, none of these ioctls even have COMPAT handling so they will
> never work from a 32-bit binary running on a 64-bit kernel for
> example.

How often does this constellation occur in reality? I really have no
idea. Our software is either 32-bit or 64-bit, not a mix.

> 
> Also:
> 
>> +static struct x25_state* state(hdlc_device *hdlc)
> 
> It is always "type *func" never "type* func"

Ok. I will change that. I've copied that from hdlc_fr.c to keep the
same coding style. But you are right:
"Don't look back, always look forward." :)
> 
>>  static int x25_open(struct net_device *dev)
>>  {
>>  	int result;
>> +	hdlc_device *hdlc = dev_to_hdlc(dev);
>> +	struct lapb_parms_struct params;
>>  	static const struct lapb_register_struct cb = {
> 
> Please make this reverse christmas tree ordered.

OK, will do.

> 
>> @@ -186,6 +217,9 @@ static struct hdlc_proto proto = {
>> 
>>  static int x25_ioctl(struct net_device *dev, struct ifreq *ifr)
>>  {
>> +	x25_hdlc_proto __user *x25_s = ifr->ifr_settings.ifs_ifsu.x25;
>> +	const size_t size = sizeof(x25_hdlc_proto);
>> +	x25_hdlc_proto new_settings;
>>  	hdlc_device *hdlc = dev_to_hdlc(dev);
>>  	int result;
> 
> Likewise.

ditto.

Patch
diff mbox series

diff --git a/drivers/net/wan/hdlc_x25.c b/drivers/net/wan/hdlc_x25.c
index 5643675ff724..0479a2bf42f7 100644
--- a/drivers/net/wan/hdlc_x25.c
+++ b/drivers/net/wan/hdlc_x25.c
@@ -21,8 +21,17 @@ 
 #include <linux/skbuff.h>
 #include <net/x25device.h>
 
+struct x25_state {
+	x25_hdlc_proto settings;
+};
+
 static int x25_ioctl(struct net_device *dev, struct ifreq *ifr);
 
+static struct x25_state* state(hdlc_device *hdlc)
+{
+	return (struct x25_state *)hdlc->state;
+}
+
 /* These functions are callbacks called by LAPB layer */
 
 static void x25_connect_disconnect(struct net_device *dev, int reason, int code)
@@ -132,6 +141,8 @@  static netdev_tx_t x25_xmit(struct sk_buff *skb, struct net_device *dev)
 static int x25_open(struct net_device *dev)
 {
 	int result;
+	hdlc_device *hdlc = dev_to_hdlc(dev);
+	struct lapb_parms_struct params;
 	static const struct lapb_register_struct cb = {
 		.connect_confirmation = x25_connected,
 		.connect_indication = x25_connected,
@@ -144,6 +155,26 @@  static int x25_open(struct net_device *dev)
 	result = lapb_register(dev, &cb);
 	if (result != LAPB_OK)
 		return result;
+
+	result = lapb_getparms(dev, &params);
+	if (result != LAPB_OK)
+		return result;
+
+	if (state(hdlc)->settings.dce)
+		params.mode = params.mode | LAPB_DCE;
+
+	if (state(hdlc)->settings.modulo == 128)
+		params.mode = params.mode | LAPB_EXTENDED;
+
+	params.window = state(hdlc)->settings.window;
+	params.t1 = state(hdlc)->settings.t1;
+	params.t2 = state(hdlc)->settings.t2;
+	params.n2 = state(hdlc)->settings.n2;
+
+	result = lapb_setparms(dev, &params);
+	if (result != LAPB_OK)
+		return result;
+
 	return 0;
 }
 
@@ -186,6 +217,9 @@  static struct hdlc_proto proto = {
 
 static int x25_ioctl(struct net_device *dev, struct ifreq *ifr)
 {
+	x25_hdlc_proto __user *x25_s = ifr->ifr_settings.ifs_ifsu.x25;
+	const size_t size = sizeof(x25_hdlc_proto);
+	x25_hdlc_proto new_settings;
 	hdlc_device *hdlc = dev_to_hdlc(dev);
 	int result;
 
@@ -194,7 +228,13 @@  static int x25_ioctl(struct net_device *dev, struct ifreq *ifr)
 		if (dev_to_hdlc(dev)->proto != &proto)
 			return -EINVAL;
 		ifr->ifr_settings.type = IF_PROTO_X25;
-		return 0; /* return protocol only, no settable parameters */
+		if (ifr->ifr_settings.size < size) {
+			ifr->ifr_settings.size = size; /* data size wanted */
+			return -ENOBUFS;
+		}
+		if (copy_to_user(x25_s, &state(hdlc)->settings, size))
+			return -EFAULT;
+		return 0;
 
 	case IF_PROTO_X25:
 		if (!capable(CAP_NET_ADMIN))
@@ -203,12 +243,46 @@  static int x25_ioctl(struct net_device *dev, struct ifreq *ifr)
 		if (dev->flags & IFF_UP)
 			return -EBUSY;
 
+		/* backward compatibility */
+		if (ifr->ifr_settings.size = 0) {
+			new_settings.dce = 0;
+			new_settings.modulo = 8;
+			new_settings.window = 7;
+			new_settings.t1 = 3;
+			new_settings.t2 = 1;
+			new_settings.n2 = 10;
+		}
+		else {
+			if (copy_from_user(&new_settings, x25_s, size))
+				return -EFAULT;
+
+			if ((new_settings.dce != 0 &&
+			new_settings.dce != 1) ||
+			(new_settings.modulo != 8 &&
+			new_settings.modulo != 128) ||
+			new_settings.window < 1 ||
+			(new_settings.modulo == 8 &&
+			new_settings.window > 7) ||
+			(new_settings.modulo == 128 &&
+			new_settings.window > 127) ||
+			new_settings.t1 < 1 ||
+			new_settings.t1 > 255 ||
+			new_settings.t2 < 1 ||
+			new_settings.t2 > 255 ||
+			new_settings.n2 < 1 ||
+			new_settings.n2 > 255)
+				return -EINVAL;
+		}
+
 		result=hdlc->attach(dev, ENCODING_NRZ,PARITY_CRC16_PR1_CCITT);
 		if (result)
 			return result;
 
-		if ((result = attach_hdlc_protocol(dev, &proto, 0)))
+		if ((result = attach_hdlc_protocol(dev, &proto,
+						   sizeof(struct x25_state))))
 			return result;
+
+		memcpy(&state(hdlc)->settings, &new_settings, size);
 		dev->type = ARPHRD_X25;
 		call_netdevice_notifiers(NETDEV_POST_TYPE_CHANGE, dev);
 		netif_dormant_off(dev);
diff --git a/include/uapi/linux/hdlc/ioctl.h b/include/uapi/linux/hdlc/ioctl.h
index 0fe4238e8246..b06341acab5e 100644
--- a/include/uapi/linux/hdlc/ioctl.h
+++ b/include/uapi/linux/hdlc/ioctl.h
@@ -79,6 +79,15 @@  typedef struct {
     unsigned int timeout;
 } cisco_proto;
 
+typedef struct {
+	unsigned short dce; /* 1 for DCE (network side) operation */
+	unsigned int modulo; /* modulo (8 = basic / 128 = extended) */
+	unsigned int window; /* frame window size */
+	unsigned int t1; /* timeout t1 */
+	unsigned int t2; /* timeout t2 */
+	unsigned int n2; /* frame retry counter */
+} x25_hdlc_proto;
+
 /* PPP doesn't need any info now - supply length = 0 to ioctl */
 
 #endif /* __ASSEMBLY__ */
diff --git a/include/uapi/linux/if.h b/include/uapi/linux/if.h
index 4bf33344aab1..be714cd8c826 100644
--- a/include/uapi/linux/if.h
+++ b/include/uapi/linux/if.h
@@ -213,6 +213,7 @@  struct if_settings {
 		fr_proto		__user *fr;
 		fr_proto_pvc		__user *fr_pvc;
 		fr_proto_pvc_info	__user *fr_pvc_info;
+		x25_hdlc_proto		__user *x25;
 
 		/* interface settings */
 		sync_serial_settings	__user *sync;