[PATCH 1/2] wan/hdlc_x25: make lapb params configurable

Martin Schiller
2020-01-13T12:46:01Z

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 | 67 ++++++++++++++++++++++++++++++++-
include/uapi/linux/hdlc/ioctl.h | 11 +++++-
include/uapi/linux/if.h | 1 +
3 files changed, 76 insertions(+), 3 deletions(-)

diff --git a/drivers/net/wan/hdlc_x25.c b/drivers/net/wan/hdlc_x25.c
index 5643675ff724..b28051eba736 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 inline 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 +243,35 @@ static int x25_ioctl(struct net_device *dev, struct ifreq *ifr)
if (dev->flags & IFF_UP)
return -EBUSY;

+ 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..3656ce8b8af0 100644
--- a/include/uapi/linux/hdlc/ioctl.h
+++ b/include/uapi/linux/hdlc/ioctl.h
@@ -3,7 +3,7 @@
#define __HDLC_IOCTL_H__

-#define GENERIC_HDLC_VERSION 4 /* For synchronization with sethdlc utility */
+#define GENERIC_HDLC_VERSION 5 /* For synchronization with sethdlc utility */

#define CLOCK_DEFAULT 0 /* Default setting */
#define CLOCK_EXT 1 /* External TX and RX clock - DTE */
@@ -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;
--
2.20.1