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-rw-r--r--net/x25/x25_link.c421
1 files changed, 421 insertions, 0 deletions
diff --git a/net/x25/x25_link.c b/net/x25/x25_link.c
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index 000000000..5460b9146
--- /dev/null
+++ b/net/x25/x25_link.c
@@ -0,0 +1,421 @@
+// 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);
+}
+
+/*
+ * 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;
+
+ switch (frametype) {
+ case X25_RESTART_REQUEST:
+ switch (nb->state) {
+ case X25_LINK_STATE_0:
+ /* This can happen when the x25 module just gets loaded
+ * and doesn't know layer 2 has already connected
+ */
+ nb->state = X25_LINK_STATE_3;
+ x25_transmit_restart_confirmation(nb);
+ break;
+ case X25_LINK_STATE_2:
+ x25_stop_t20timer(nb);
+ nb->state = X25_LINK_STATE_3;
+ break;
+ case X25_LINK_STATE_3:
+ /* clear existing virtual calls */
+ x25_kill_by_neigh(nb);
+
+ x25_transmit_restart_confirmation(nb);
+ break;
+ }
+ break;
+
+ case X25_RESTART_CONFIRMATION:
+ switch (nb->state) {
+ case X25_LINK_STATE_2:
+ x25_stop_t20timer(nb);
+ nb->state = X25_LINK_STATE_3;
+ break;
+ case X25_LINK_STATE_3:
+ /* clear existing virtual calls */
+ x25_kill_by_neigh(nb);
+
+ x25_transmit_restart_request(nb);
+ nb->state = X25_LINK_STATE_2;
+ x25_start_t20timer(nb);
+ break;
+ }
+ 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:
+ 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;
+ skb_queue_purge(&nb->queue);
+ x25_stop_t20timer(nb);
+
+ /* 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)
+{
+ 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;
+
+ read_lock_bh(&x25_neigh_list_lock);
+ list_for_each_entry(nb, &x25_neigh_list, 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);
+}
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