1 files changed, 406 insertions, 0 deletions
diff --git a/net/x25/x25_link.c b/net/x25/x25_link.c
new file mode 100644
index 000000000..fdae054b7
--- /dev/null
+++ b/net/x25/x25_link.c
@@ -0,0 +1,406 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *	X.25 Packet Layer release 002
+ *
+ *	This is ALPHA test software. This code may break your machine,
+ *	randomly fail to work with new releases, misbehave and/or generally
+ *	screw up. It might even work.
+ *
+ *	This code REQUIRES 2.1.15 or higher
+ *
+ *	History
+ *	X.25 001	Jonathan Naylor	  Started coding.
+ *	X.25 002	Jonathan Naylor	  New timer architecture.
+ *	mar/20/00	Daniela Squassoni Disabling/enabling of facilities
+ *					  negotiation.
+ *	2000-09-04	Henner Eisen	  dev_hold() / dev_put() for x25_neigh.
+ */
+
+#define pr_fmt(fmt) "X25: " fmt
+
+#include <linux/kernel.h>
+#include <linux/jiffies.h>
+#include <linux/timer.h>
+#include <linux/slab.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <linux/uaccess.h>
+#include <linux/init.h>
+#include <net/x25.h>
+
+LIST_HEAD(x25_neigh_list);
+DEFINE_RWLOCK(x25_neigh_list_lock);
+
+static void x25_t20timer_expiry(struct timer_list *);
+
+static void x25_transmit_restart_confirmation(struct x25_neigh *nb);
+static void x25_transmit_restart_request(struct x25_neigh *nb);
+
+/*
+ *	Linux set/reset timer routines
+ */
+static inline void x25_start_t20timer(struct x25_neigh *nb)
+{
+	mod_timer(&nb->t20timer, jiffies + nb->t20);
+}
+
+static void x25_t20timer_expiry(struct timer_list *t)
+{
+	struct x25_neigh *nb = from_timer(nb, t, t20timer);
+
+	x25_transmit_restart_request(nb);
+
+	x25_start_t20timer(nb);
+}
+
+static inline void x25_stop_t20timer(struct x25_neigh *nb)
+{
+	del_timer(&nb->t20timer);
+}
+
+static inline int x25_t20timer_pending(struct x25_neigh *nb)
+{
+	return timer_pending(&nb->t20timer);
+}
+
+/*
+ *	This handles all restart and diagnostic frames.
+ */
+void x25_link_control(struct sk_buff *skb, struct x25_neigh *nb,
+		      unsigned short frametype)
+{
+	struct sk_buff *skbn;
+	int confirm;
+
+	switch (frametype) {
+	case X25_RESTART_REQUEST:
+		confirm = !x25_t20timer_pending(nb);
+		x25_stop_t20timer(nb);
+		nb->state = X25_LINK_STATE_3;
+		if (confirm)
+			x25_transmit_restart_confirmation(nb);
+		break;
+
+	case X25_RESTART_CONFIRMATION:
+		x25_stop_t20timer(nb);
+		nb->state = X25_LINK_STATE_3;
+		break;
+
+	case X25_DIAGNOSTIC:
+		if (!pskb_may_pull(skb, X25_STD_MIN_LEN + 4))
+			break;
+
+		pr_warn("diagnostic #%d - %02X %02X %02X\n",
+		       skb->data[3], skb->data[4],
+		       skb->data[5], skb->data[6]);
+		break;
+
+	default:
+		pr_warn("received unknown %02X with LCI 000\n",
+		       frametype);
+		break;
+	}
+
+	if (nb->state == X25_LINK_STATE_3)
+		while ((skbn = skb_dequeue(&nb->queue)) != NULL)
+			x25_send_frame(skbn, nb);
+}
+
+/*
+ *	This routine is called when a Restart Request is needed
+ */
+static void x25_transmit_restart_request(struct x25_neigh *nb)
+{
+	unsigned char *dptr;
+	int len = X25_MAX_L2_LEN + X25_STD_MIN_LEN + 2;
+	struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC);
+
+	if (!skb)
+		return;
+
+	skb_reserve(skb, X25_MAX_L2_LEN);
+
+	dptr = skb_put(skb, X25_STD_MIN_LEN + 2);
+
+	*dptr++ = nb->extended ? X25_GFI_EXTSEQ : X25_GFI_STDSEQ;
+	*dptr++ = 0x00;
+	*dptr++ = X25_RESTART_REQUEST;
+	*dptr++ = 0x00;
+	*dptr++ = 0;
+
+	skb->sk = NULL;
+
+	x25_send_frame(skb, nb);
+}
+
+/*
+ * This routine is called when a Restart Confirmation is needed
+ */
+static void x25_transmit_restart_confirmation(struct x25_neigh *nb)
+{
+	unsigned char *dptr;
+	int len = X25_MAX_L2_LEN + X25_STD_MIN_LEN;
+	struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC);
+
+	if (!skb)
+		return;
+
+	skb_reserve(skb, X25_MAX_L2_LEN);
+
+	dptr = skb_put(skb, X25_STD_MIN_LEN);
+
+	*dptr++ = nb->extended ? X25_GFI_EXTSEQ : X25_GFI_STDSEQ;
+	*dptr++ = 0x00;
+	*dptr++ = X25_RESTART_CONFIRMATION;
+
+	skb->sk = NULL;
+
+	x25_send_frame(skb, nb);
+}
+
+/*
+ *	This routine is called when a Clear Request is needed outside of the context
+ *	of a connected socket.
+ */
+void x25_transmit_clear_request(struct x25_neigh *nb, unsigned int lci,
+				unsigned char cause)
+{
+	unsigned char *dptr;
+	int len = X25_MAX_L2_LEN + X25_STD_MIN_LEN + 2;
+	struct sk_buff *skb = alloc_skb(len, GFP_ATOMIC);
+
+	if (!skb)
+		return;
+
+	skb_reserve(skb, X25_MAX_L2_LEN);
+
+	dptr = skb_put(skb, X25_STD_MIN_LEN + 2);
+
+	*dptr++ = ((lci >> 8) & 0x0F) | (nb->extended ?
+					 X25_GFI_EXTSEQ :
+					 X25_GFI_STDSEQ);
+	*dptr++ = (lci >> 0) & 0xFF;
+	*dptr++ = X25_CLEAR_REQUEST;
+	*dptr++ = cause;
+	*dptr++ = 0x00;
+
+	skb->sk = NULL;
+
+	x25_send_frame(skb, nb);
+}
+
+void x25_transmit_link(struct sk_buff *skb, struct x25_neigh *nb)
+{
+	switch (nb->state) {
+	case X25_LINK_STATE_0:
+		skb_queue_tail(&nb->queue, skb);
+		nb->state = X25_LINK_STATE_1;
+		x25_establish_link(nb);
+		break;
+	case X25_LINK_STATE_1:
+	case X25_LINK_STATE_2:
+		skb_queue_tail(&nb->queue, skb);
+		break;
+	case X25_LINK_STATE_3:
+		x25_send_frame(skb, nb);
+		break;
+	}
+}
+
+/*
+ *	Called when the link layer has become established.
+ */
+void x25_link_established(struct x25_neigh *nb)
+{
+	switch (nb->state) {
+	case X25_LINK_STATE_0:
+		nb->state = X25_LINK_STATE_2;
+		break;
+	case X25_LINK_STATE_1:
+		x25_transmit_restart_request(nb);
+		nb->state = X25_LINK_STATE_2;
+		x25_start_t20timer(nb);
+		break;
+	}
+}
+
+/*
+ *	Called when the link layer has terminated, or an establishment
+ *	request has failed.
+ */
+
+void x25_link_terminated(struct x25_neigh *nb)
+{
+	nb->state = X25_LINK_STATE_0;
+	/* Out of order: clear existing virtual calls (X.25 03/93 4.6.3) */
+	x25_kill_by_neigh(nb);
+}
+
+/*
+ *	Add a new device.
+ */
+void x25_link_device_up(struct net_device *dev)
+{
+	struct x25_neigh *nb = kmalloc(sizeof(*nb), GFP_ATOMIC);
+
+	if (!nb)
+		return;
+
+	skb_queue_head_init(&nb->queue);
+	timer_setup(&nb->t20timer, x25_t20timer_expiry, 0);
+
+	dev_hold(dev);
+	nb->dev      = dev;
+	nb->state    = X25_LINK_STATE_0;
+	nb->extended = 0;
+	/*
+	 * Enables negotiation
+	 */
+	nb->global_facil_mask = X25_MASK_REVERSE |
+				       X25_MASK_THROUGHPUT |
+				       X25_MASK_PACKET_SIZE |
+				       X25_MASK_WINDOW_SIZE;
+	nb->t20      = sysctl_x25_restart_request_timeout;
+	refcount_set(&nb->refcnt, 1);
+
+	write_lock_bh(&x25_neigh_list_lock);
+	list_add(&nb->node, &x25_neigh_list);
+	write_unlock_bh(&x25_neigh_list_lock);
+}
+
+/**
+ *	__x25_remove_neigh - remove neighbour from x25_neigh_list
+ *	@nb: - neigh to remove
+ *
+ *	Remove neighbour from x25_neigh_list. If it was there.
+ *	Caller must hold x25_neigh_list_lock.
+ */
+static void __x25_remove_neigh(struct x25_neigh *nb)
+{
+	skb_queue_purge(&nb->queue);
+	x25_stop_t20timer(nb);
+
+	if (nb->node.next) {
+		list_del(&nb->node);
+		x25_neigh_put(nb);
+	}
+}
+
+/*
+ *	A device has been removed, remove its links.
+ */
+void x25_link_device_down(struct net_device *dev)
+{
+	struct x25_neigh *nb;
+	struct list_head *entry, *tmp;
+
+	write_lock_bh(&x25_neigh_list_lock);
+
+	list_for_each_safe(entry, tmp, &x25_neigh_list) {
+		nb = list_entry(entry, struct x25_neigh, node);
+
+		if (nb->dev == dev) {
+			__x25_remove_neigh(nb);
+			dev_put(dev);
+		}
+	}
+
+	write_unlock_bh(&x25_neigh_list_lock);
+}
+
+/*
+ *	Given a device, return the neighbour address.
+ */
+struct x25_neigh *x25_get_neigh(struct net_device *dev)
+{
+	struct x25_neigh *nb, *use = NULL;
+	struct list_head *entry;
+
+	read_lock_bh(&x25_neigh_list_lock);
+	list_for_each(entry, &x25_neigh_list) {
+		nb = list_entry(entry, struct x25_neigh, node);
+
+		if (nb->dev == dev) {
+			use = nb;
+			break;
+		}
+	}
+
+	if (use)
+		x25_neigh_hold(use);
+	read_unlock_bh(&x25_neigh_list_lock);
+	return use;
+}
+
+/*
+ *	Handle the ioctls that control the subscription functions.
+ */
+int x25_subscr_ioctl(unsigned int cmd, void __user *arg)
+{
+	struct x25_subscrip_struct x25_subscr;
+	struct x25_neigh *nb;
+	struct net_device *dev;
+	int rc = -EINVAL;
+
+	if (cmd != SIOCX25GSUBSCRIP && cmd != SIOCX25SSUBSCRIP)
+		goto out;
+
+	rc = -EFAULT;
+	if (copy_from_user(&x25_subscr, arg, sizeof(x25_subscr)))
+		goto out;
+
+	rc = -EINVAL;
+	if ((dev = x25_dev_get(x25_subscr.device)) == NULL)
+		goto out;
+
+	if ((nb = x25_get_neigh(dev)) == NULL)
+		goto out_dev_put;
+
+	dev_put(dev);
+
+	if (cmd == SIOCX25GSUBSCRIP) {
+		read_lock_bh(&x25_neigh_list_lock);
+		x25_subscr.extended	     = nb->extended;
+		x25_subscr.global_facil_mask = nb->global_facil_mask;
+		read_unlock_bh(&x25_neigh_list_lock);
+		rc = copy_to_user(arg, &x25_subscr,
+				  sizeof(x25_subscr)) ? -EFAULT : 0;
+	} else {
+		rc = -EINVAL;
+		if (!(x25_subscr.extended && x25_subscr.extended != 1)) {
+			rc = 0;
+			write_lock_bh(&x25_neigh_list_lock);
+			nb->extended	     = x25_subscr.extended;
+			nb->global_facil_mask = x25_subscr.global_facil_mask;
+			write_unlock_bh(&x25_neigh_list_lock);
+		}
+	}
+	x25_neigh_put(nb);
+out:
+	return rc;
+out_dev_put:
+	dev_put(dev);
+	goto out;
+}
+
+
+/*
+ *	Release all memory associated with X.25 neighbour structures.
+ */
+void __exit x25_link_free(void)
+{
+	struct x25_neigh *nb;
+	struct list_head *entry, *tmp;
+
+	write_lock_bh(&x25_neigh_list_lock);
+
+	list_for_each_safe(entry, tmp, &x25_neigh_list) {
+		struct net_device *dev;
+
+		nb = list_entry(entry, struct x25_neigh, node);
+		dev = nb->dev;
+		__x25_remove_neigh(nb);
+		dev_put(dev);
+	}
+	write_unlock_bh(&x25_neigh_list_lock);
+}