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-rw-r--r--net/lapb/lapb_out.c205
1 files changed, 205 insertions, 0 deletions
diff --git a/net/lapb/lapb_out.c b/net/lapb/lapb_out.c
new file mode 100644
index 000000000..a966d29c7
--- /dev/null
+++ b/net/lapb/lapb_out.c
@@ -0,0 +1,205 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * LAPB release 002
+ *
+ * This code REQUIRES 2.1.15 or higher/ NET3.038
+ *
+ * History
+ * LAPB 001 Jonathan Naylor Started Coding
+ * LAPB 002 Jonathan Naylor New timer architecture.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/socket.h>
+#include <linux/in.h>
+#include <linux/kernel.h>
+#include <linux/timer.h>
+#include <linux/string.h>
+#include <linux/sockios.h>
+#include <linux/net.h>
+#include <linux/inet.h>
+#include <linux/skbuff.h>
+#include <linux/slab.h>
+#include <net/sock.h>
+#include <linux/uaccess.h>
+#include <linux/fcntl.h>
+#include <linux/mm.h>
+#include <linux/interrupt.h>
+#include <net/lapb.h>
+
+/*
+ * This procedure is passed a buffer descriptor for an iframe. It builds
+ * the rest of the control part of the frame and then writes it out.
+ */
+static void lapb_send_iframe(struct lapb_cb *lapb, struct sk_buff *skb, int poll_bit)
+{
+ unsigned char *frame;
+
+ if (!skb)
+ return;
+
+ if (lapb->mode & LAPB_EXTENDED) {
+ frame = skb_push(skb, 2);
+
+ frame[0] = LAPB_I;
+ frame[0] |= lapb->vs << 1;
+ frame[1] = poll_bit ? LAPB_EPF : 0;
+ frame[1] |= lapb->vr << 1;
+ } else {
+ frame = skb_push(skb, 1);
+
+ *frame = LAPB_I;
+ *frame |= poll_bit ? LAPB_SPF : 0;
+ *frame |= lapb->vr << 5;
+ *frame |= lapb->vs << 1;
+ }
+
+ lapb_dbg(1, "(%p) S%d TX I(%d) S%d R%d\n",
+ lapb->dev, lapb->state, poll_bit, lapb->vs, lapb->vr);
+
+ lapb_transmit_buffer(lapb, skb, LAPB_COMMAND);
+}
+
+void lapb_kick(struct lapb_cb *lapb)
+{
+ struct sk_buff *skb, *skbn;
+ unsigned short modulus, start, end;
+
+ modulus = (lapb->mode & LAPB_EXTENDED) ? LAPB_EMODULUS : LAPB_SMODULUS;
+ start = !skb_peek(&lapb->ack_queue) ? lapb->va : lapb->vs;
+ end = (lapb->va + lapb->window) % modulus;
+
+ if (!(lapb->condition & LAPB_PEER_RX_BUSY_CONDITION) &&
+ start != end && skb_peek(&lapb->write_queue)) {
+ lapb->vs = start;
+
+ /*
+ * Dequeue the frame and copy it.
+ */
+ skb = skb_dequeue(&lapb->write_queue);
+
+ do {
+ skbn = skb_copy(skb, GFP_ATOMIC);
+ if (!skbn) {
+ skb_queue_head(&lapb->write_queue, skb);
+ break;
+ }
+
+ if (skb->sk)
+ skb_set_owner_w(skbn, skb->sk);
+
+ /*
+ * Transmit the frame copy.
+ */
+ lapb_send_iframe(lapb, skbn, LAPB_POLLOFF);
+
+ lapb->vs = (lapb->vs + 1) % modulus;
+
+ /*
+ * Requeue the original data frame.
+ */
+ skb_queue_tail(&lapb->ack_queue, skb);
+
+ } while (lapb->vs != end && (skb = skb_dequeue(&lapb->write_queue)) != NULL);
+
+ lapb->condition &= ~LAPB_ACK_PENDING_CONDITION;
+
+ if (!lapb_t1timer_running(lapb))
+ lapb_start_t1timer(lapb);
+ }
+}
+
+void lapb_transmit_buffer(struct lapb_cb *lapb, struct sk_buff *skb, int type)
+{
+ unsigned char *ptr;
+
+ ptr = skb_push(skb, 1);
+
+ if (lapb->mode & LAPB_MLP) {
+ if (lapb->mode & LAPB_DCE) {
+ if (type == LAPB_COMMAND)
+ *ptr = LAPB_ADDR_C;
+ if (type == LAPB_RESPONSE)
+ *ptr = LAPB_ADDR_D;
+ } else {
+ if (type == LAPB_COMMAND)
+ *ptr = LAPB_ADDR_D;
+ if (type == LAPB_RESPONSE)
+ *ptr = LAPB_ADDR_C;
+ }
+ } else {
+ if (lapb->mode & LAPB_DCE) {
+ if (type == LAPB_COMMAND)
+ *ptr = LAPB_ADDR_A;
+ if (type == LAPB_RESPONSE)
+ *ptr = LAPB_ADDR_B;
+ } else {
+ if (type == LAPB_COMMAND)
+ *ptr = LAPB_ADDR_B;
+ if (type == LAPB_RESPONSE)
+ *ptr = LAPB_ADDR_A;
+ }
+ }
+
+ lapb_dbg(2, "(%p) S%d TX %3ph\n", lapb->dev, lapb->state, skb->data);
+
+ if (!lapb_data_transmit(lapb, skb))
+ kfree_skb(skb);
+}
+
+void lapb_establish_data_link(struct lapb_cb *lapb)
+{
+ lapb->condition = 0x00;
+ lapb->n2count = 0;
+
+ if (lapb->mode & LAPB_EXTENDED) {
+ lapb_dbg(1, "(%p) S%d TX SABME(1)\n", lapb->dev, lapb->state);
+ lapb_send_control(lapb, LAPB_SABME, LAPB_POLLON, LAPB_COMMAND);
+ } else {
+ lapb_dbg(1, "(%p) S%d TX SABM(1)\n", lapb->dev, lapb->state);
+ lapb_send_control(lapb, LAPB_SABM, LAPB_POLLON, LAPB_COMMAND);
+ }
+
+ lapb_start_t1timer(lapb);
+ lapb_stop_t2timer(lapb);
+}
+
+void lapb_enquiry_response(struct lapb_cb *lapb)
+{
+ lapb_dbg(1, "(%p) S%d TX RR(1) R%d\n",
+ lapb->dev, lapb->state, lapb->vr);
+
+ lapb_send_control(lapb, LAPB_RR, LAPB_POLLON, LAPB_RESPONSE);
+
+ lapb->condition &= ~LAPB_ACK_PENDING_CONDITION;
+}
+
+void lapb_timeout_response(struct lapb_cb *lapb)
+{
+ lapb_dbg(1, "(%p) S%d TX RR(0) R%d\n",
+ lapb->dev, lapb->state, lapb->vr);
+ lapb_send_control(lapb, LAPB_RR, LAPB_POLLOFF, LAPB_RESPONSE);
+
+ lapb->condition &= ~LAPB_ACK_PENDING_CONDITION;
+}
+
+void lapb_check_iframes_acked(struct lapb_cb *lapb, unsigned short nr)
+{
+ if (lapb->vs == nr) {
+ lapb_frames_acked(lapb, nr);
+ lapb_stop_t1timer(lapb);
+ lapb->n2count = 0;
+ } else if (lapb->va != nr) {
+ lapb_frames_acked(lapb, nr);
+ lapb_start_t1timer(lapb);
+ }
+}
+
+void lapb_check_need_response(struct lapb_cb *lapb, int type, int pf)
+{
+ if (type == LAPB_COMMAND && pf)
+ lapb_enquiry_response(lapb);
+}