Commit 13458ffe authored by Xie He's avatar Xie He Committed by Jakub Kicinski
Browse files

net: x25: Remove unimplemented X.25-over-LLC code stubs 



According to the X.25 documentation, there was a plan to implement
X.25-over-802.2-LLC. It never finished but left various code stubs in the
X.25 code. At this time it is unlikely that it would ever finish so it
may be better to remove those code stubs.

Also change the documentation to make it clear that this is not a ongoing
plan anymore. Change words like "will" to "could", "would", etc.

Cc: Martin Schiller <ms@dev.tdt.de>
Signed-off-by: default avatarXie He <xie.he.0141@gmail.com>
Link: https://lore.kernel.org/r/20201209033346.83742-1-xie.he.0141@gmail.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 0b9b2414

Documentation/networking/x25.rst

+5 −7
Original line number Diff line number Diff line
@@ -19,13 +19,11 @@ implementation of LAPB. Therefore the LAPB modules would be called by 
unintelligent X.25 card drivers and not by intelligent ones, this would

provide a uniform device driver interface, and simplify configuration.



To confuse matters a little, an 802.2 LLC implementation for Linux is being

written which will allow X.25 to be run over an Ethernet (or Token Ring) and

conform with the JNT "Pink Book", this will have a different interface to

the Packet Layer but there will be no confusion since the class of device

being served by the LLC will be completely separate from LAPB. The LLC

implementation is being done as part of another protocol project (SNA) and

by a different author.

To confuse matters a little, an 802.2 LLC implementation is also possible

which could allow X.25 to be run over an Ethernet (or Token Ring) and

conform with the JNT "Pink Book", this would have a different interface to

the Packet Layer but there would be no confusion since the class of device

being served by the LLC would be completely separate from LAPB.



Just when you thought that it could not become more confusing, another

option appeared, XOT. This allows X.25 Packet Layer frames to operate over

net/x25/af_x25.c

+1 −5
Original line number Diff line number Diff line
@@ -211,11 +211,7 @@ static int x25_device_event(struct notifier_block *this, unsigned long event, 
	if (!net_eq(dev_net(dev), &init_net))

		return NOTIFY_DONE;



	if (dev->type == ARPHRD_X25

#if IS_ENABLED(CONFIG_LLC)

	 || dev->type == ARPHRD_ETHER

#endif

	 ) {

	if (dev->type == ARPHRD_X25) {

		switch (event) {

		case NETDEV_REGISTER:

		case NETDEV_POST_TYPE_CHANGE:

net/x25/x25_dev.c

+0 −13
Original line number Diff line number Diff line
@@ -160,10 +160,6 @@ void x25_establish_link(struct x25_neigh *nb) 
		*ptr = X25_IFACE_CONNECT;

		break;



#if IS_ENABLED(CONFIG_LLC)

	case ARPHRD_ETHER:

		return;

#endif

	default:

		return;

	}
@@ -179,10 +175,6 @@ void x25_terminate_link(struct x25_neigh *nb) 
	struct sk_buff *skb;

	unsigned char *ptr;



#if IS_ENABLED(CONFIG_LLC)

	if (nb->dev->type == ARPHRD_ETHER)

		return;

#endif

	if (nb->dev->type != ARPHRD_X25)

		return;
@@ -212,11 +204,6 @@ void x25_send_frame(struct sk_buff *skb, struct x25_neigh *nb) 
		*dptr = X25_IFACE_DATA;

		break;



#if IS_ENABLED(CONFIG_LLC)

	case ARPHRD_ETHER:

		kfree_skb(skb);

		return;

#endif

	default:

		kfree_skb(skb);

		return;

net/x25/x25_route.c

+1 −6
Original line number Diff line number Diff line
@@ -124,12 +124,7 @@ struct net_device *x25_dev_get(char *devname) 
{

	struct net_device *dev = dev_get_by_name(&init_net, devname);



	if (dev &&

	    (!(dev->flags & IFF_UP) || (dev->type != ARPHRD_X25

#if IS_ENABLED(CONFIG_LLC)

					&& dev->type != ARPHRD_ETHER

#endif

					))){

	if (dev && (!(dev->flags & IFF_UP) || dev->type != ARPHRD_X25)) {

		dev_put(dev);

		dev = NULL;

	}

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