summaryrefslogtreecommitdiffstats
path: root/net/netrom/nr_out.c
diff options
context:
space:
mode:
Diffstat (limited to 'net/netrom/nr_out.c')
-rw-r--r--net/netrom/nr_out.c273
1 files changed, 273 insertions, 0 deletions
diff --git a/net/netrom/nr_out.c b/net/netrom/nr_out.c
new file mode 100644
index 000000000..00fbf1419
--- /dev/null
+++ b/net/netrom/nr_out.c
@@ -0,0 +1,273 @@
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * Copyright Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
+ * Copyright Darryl Miles G7LED (dlm@g7led.demon.co.uk)
+ */
+#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/slab.h>
+#include <net/ax25.h>
+#include <linux/inet.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <linux/uaccess.h>
+#include <linux/fcntl.h>
+#include <linux/mm.h>
+#include <linux/interrupt.h>
+#include <net/netrom.h>
+
+/*
+ * This is where all NET/ROM frames pass, except for IP-over-NET/ROM which
+ * cannot be fragmented in this manner.
+ */
+void nr_output(struct sock *sk, struct sk_buff *skb)
+{
+ struct sk_buff *skbn;
+ unsigned char transport[NR_TRANSPORT_LEN];
+ int err, frontlen, len;
+
+ if (skb->len - NR_TRANSPORT_LEN > NR_MAX_PACKET_SIZE) {
+ /* Save a copy of the Transport Header */
+ skb_copy_from_linear_data(skb, transport, NR_TRANSPORT_LEN);
+ skb_pull(skb, NR_TRANSPORT_LEN);
+
+ frontlen = skb_headroom(skb);
+
+ while (skb->len > 0) {
+ if ((skbn = sock_alloc_send_skb(sk, frontlen + NR_MAX_PACKET_SIZE, 0, &err)) == NULL)
+ return;
+
+ skb_reserve(skbn, frontlen);
+
+ len = (NR_MAX_PACKET_SIZE > skb->len) ? skb->len : NR_MAX_PACKET_SIZE;
+
+ /* Copy the user data */
+ skb_copy_from_linear_data(skb, skb_put(skbn, len), len);
+ skb_pull(skb, len);
+
+ /* Duplicate the Transport Header */
+ skb_push(skbn, NR_TRANSPORT_LEN);
+ skb_copy_to_linear_data(skbn, transport,
+ NR_TRANSPORT_LEN);
+ if (skb->len > 0)
+ skbn->data[4] |= NR_MORE_FLAG;
+
+ skb_queue_tail(&sk->sk_write_queue, skbn); /* Throw it on the queue */
+ }
+
+ kfree_skb(skb);
+ } else {
+ skb_queue_tail(&sk->sk_write_queue, skb); /* Throw it on the queue */
+ }
+
+ nr_kick(sk);
+}
+
+/*
+ * 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 nr_send_iframe(struct sock *sk, struct sk_buff *skb)
+{
+ struct nr_sock *nr = nr_sk(sk);
+
+ if (skb == NULL)
+ return;
+
+ skb->data[2] = nr->vs;
+ skb->data[3] = nr->vr;
+
+ if (nr->condition & NR_COND_OWN_RX_BUSY)
+ skb->data[4] |= NR_CHOKE_FLAG;
+
+ nr_start_idletimer(sk);
+
+ nr_transmit_buffer(sk, skb);
+}
+
+void nr_send_nak_frame(struct sock *sk)
+{
+ struct sk_buff *skb, *skbn;
+ struct nr_sock *nr = nr_sk(sk);
+
+ if ((skb = skb_peek(&nr->ack_queue)) == NULL)
+ return;
+
+ if ((skbn = skb_clone(skb, GFP_ATOMIC)) == NULL)
+ return;
+
+ skbn->data[2] = nr->va;
+ skbn->data[3] = nr->vr;
+
+ if (nr->condition & NR_COND_OWN_RX_BUSY)
+ skbn->data[4] |= NR_CHOKE_FLAG;
+
+ nr_transmit_buffer(sk, skbn);
+
+ nr->condition &= ~NR_COND_ACK_PENDING;
+ nr->vl = nr->vr;
+
+ nr_stop_t1timer(sk);
+}
+
+void nr_kick(struct sock *sk)
+{
+ struct nr_sock *nr = nr_sk(sk);
+ struct sk_buff *skb, *skbn;
+ unsigned short start, end;
+
+ if (nr->state != NR_STATE_3)
+ return;
+
+ if (nr->condition & NR_COND_PEER_RX_BUSY)
+ return;
+
+ if (!skb_peek(&sk->sk_write_queue))
+ return;
+
+ start = (skb_peek(&nr->ack_queue) == NULL) ? nr->va : nr->vs;
+ end = (nr->va + nr->window) % NR_MODULUS;
+
+ if (start == end)
+ return;
+
+ nr->vs = start;
+
+ /*
+ * Transmit data until either we're out of data to send or
+ * the window is full.
+ */
+
+ /*
+ * Dequeue the frame and copy it.
+ */
+ skb = skb_dequeue(&sk->sk_write_queue);
+
+ do {
+ if ((skbn = skb_clone(skb, GFP_ATOMIC)) == NULL) {
+ skb_queue_head(&sk->sk_write_queue, skb);
+ break;
+ }
+
+ skb_set_owner_w(skbn, sk);
+
+ /*
+ * Transmit the frame copy.
+ */
+ nr_send_iframe(sk, skbn);
+
+ nr->vs = (nr->vs + 1) % NR_MODULUS;
+
+ /*
+ * Requeue the original data frame.
+ */
+ skb_queue_tail(&nr->ack_queue, skb);
+
+ } while (nr->vs != end &&
+ (skb = skb_dequeue(&sk->sk_write_queue)) != NULL);
+
+ nr->vl = nr->vr;
+ nr->condition &= ~NR_COND_ACK_PENDING;
+
+ if (!nr_t1timer_running(sk))
+ nr_start_t1timer(sk);
+}
+
+void nr_transmit_buffer(struct sock *sk, struct sk_buff *skb)
+{
+ struct nr_sock *nr = nr_sk(sk);
+ unsigned char *dptr;
+
+ /*
+ * Add the protocol byte and network header.
+ */
+ dptr = skb_push(skb, NR_NETWORK_LEN);
+
+ memcpy(dptr, &nr->source_addr, AX25_ADDR_LEN);
+ dptr[6] &= ~AX25_CBIT;
+ dptr[6] &= ~AX25_EBIT;
+ dptr[6] |= AX25_SSSID_SPARE;
+ dptr += AX25_ADDR_LEN;
+
+ memcpy(dptr, &nr->dest_addr, AX25_ADDR_LEN);
+ dptr[6] &= ~AX25_CBIT;
+ dptr[6] |= AX25_EBIT;
+ dptr[6] |= AX25_SSSID_SPARE;
+ dptr += AX25_ADDR_LEN;
+
+ *dptr++ = sysctl_netrom_network_ttl_initialiser;
+
+ if (!nr_route_frame(skb, NULL)) {
+ kfree_skb(skb);
+ nr_disconnect(sk, ENETUNREACH);
+ }
+}
+
+/*
+ * The following routines are taken from page 170 of the 7th ARRL Computer
+ * Networking Conference paper, as is the whole state machine.
+ */
+
+void nr_establish_data_link(struct sock *sk)
+{
+ struct nr_sock *nr = nr_sk(sk);
+
+ nr->condition = 0x00;
+ nr->n2count = 0;
+
+ nr_write_internal(sk, NR_CONNREQ);
+
+ nr_stop_t2timer(sk);
+ nr_stop_t4timer(sk);
+ nr_stop_idletimer(sk);
+ nr_start_t1timer(sk);
+}
+
+/*
+ * Never send a NAK when we are CHOKEd.
+ */
+void nr_enquiry_response(struct sock *sk)
+{
+ struct nr_sock *nr = nr_sk(sk);
+ int frametype = NR_INFOACK;
+
+ if (nr->condition & NR_COND_OWN_RX_BUSY) {
+ frametype |= NR_CHOKE_FLAG;
+ } else {
+ if (skb_peek(&nr->reseq_queue) != NULL)
+ frametype |= NR_NAK_FLAG;
+ }
+
+ nr_write_internal(sk, frametype);
+
+ nr->vl = nr->vr;
+ nr->condition &= ~NR_COND_ACK_PENDING;
+}
+
+void nr_check_iframes_acked(struct sock *sk, unsigned short nr)
+{
+ struct nr_sock *nrom = nr_sk(sk);
+
+ if (nrom->vs == nr) {
+ nr_frames_acked(sk, nr);
+ nr_stop_t1timer(sk);
+ nrom->n2count = 0;
+ } else {
+ if (nrom->va != nr) {
+ nr_frames_acked(sk, nr);
+ nr_start_t1timer(sk);
+ }
+ }
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-25 17:15:50 +0000