aboutsummaryrefslogtreecommitdiff
path: root/net/x25/x25_out.c
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /net/x25/x25_out.c
downloadlinux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'net/x25/x25_out.c')
-rw-r--r--net/x25/x25_out.c226
1 files changed, 226 insertions, 0 deletions
diff --git a/net/x25/x25_out.c b/net/x25/x25_out.c
new file mode 100644
index 00000000000..a2e62cea819
--- /dev/null
+++ b/net/x25/x25_out.c
@@ -0,0 +1,226 @@
+/*
+ * 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
+ *
+ * This module:
+ * This module 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.
+ *
+ * History
+ * X.25 001 Jonathan Naylor Started coding.
+ * X.25 002 Jonathan Naylor New timer architecture.
+ * 2000-09-04 Henner Eisen Prevented x25_output() skb leakage.
+ * 2000-10-27 Henner Eisen MSG_DONTWAIT for fragment allocation.
+ * 2000-11-10 Henner Eisen x25_send_iframe(): re-queued frames
+ * needed cleaned seq-number fields.
+ */
+
+#include <linux/socket.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <net/x25.h>
+
+static int x25_pacsize_to_bytes(unsigned int pacsize)
+{
+ int bytes = 1;
+
+ if (!pacsize)
+ return 128;
+
+ while (pacsize-- > 0)
+ bytes *= 2;
+
+ return bytes;
+}
+
+/*
+ * This is where all X.25 information frames pass.
+ *
+ * Returns the amount of user data bytes sent on success
+ * or a negative error code on failure.
+ */
+int x25_output(struct sock *sk, struct sk_buff *skb)
+{
+ struct sk_buff *skbn;
+ unsigned char header[X25_EXT_MIN_LEN];
+ int err, frontlen, len;
+ int sent=0, noblock = X25_SKB_CB(skb)->flags & MSG_DONTWAIT;
+ struct x25_sock *x25 = x25_sk(sk);
+ int header_len = x25->neighbour->extended ? X25_EXT_MIN_LEN :
+ X25_STD_MIN_LEN;
+ int max_len = x25_pacsize_to_bytes(x25->facilities.pacsize_out);
+
+ if (skb->len - header_len > max_len) {
+ /* Save a copy of the Header */
+ memcpy(header, skb->data, header_len);
+ skb_pull(skb, header_len);
+
+ frontlen = skb_headroom(skb);
+
+ while (skb->len > 0) {
+ if ((skbn = sock_alloc_send_skb(sk, frontlen + max_len,
+ noblock, &err)) == NULL){
+ if (err == -EWOULDBLOCK && noblock){
+ kfree_skb(skb);
+ return sent;
+ }
+ SOCK_DEBUG(sk, "x25_output: fragment alloc"
+ " failed, err=%d, %d bytes "
+ "sent\n", err, sent);
+ return err;
+ }
+
+ skb_reserve(skbn, frontlen);
+
+ len = max_len > skb->len ? skb->len : max_len;
+
+ /* Copy the user data */
+ memcpy(skb_put(skbn, len), skb->data, len);
+ skb_pull(skb, len);
+
+ /* Duplicate the Header */
+ skb_push(skbn, header_len);
+ memcpy(skbn->data, header, header_len);
+
+ if (skb->len > 0) {
+ if (x25->neighbour->extended)
+ skbn->data[3] |= X25_EXT_M_BIT;
+ else
+ skbn->data[2] |= X25_STD_M_BIT;
+ }
+
+ skb_queue_tail(&sk->sk_write_queue, skbn);
+ sent += len;
+ }
+
+ kfree_skb(skb);
+ } else {
+ skb_queue_tail(&sk->sk_write_queue, skb);
+ sent = skb->len - header_len;
+ }
+ return sent;
+}
+
+/*
+ * 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 x25_send_iframe(struct sock *sk, struct sk_buff *skb)
+{
+ struct x25_sock *x25 = x25_sk(sk);
+
+ if (!skb)
+ return;
+
+ if (x25->neighbour->extended) {
+ skb->data[2] = (x25->vs << 1) & 0xFE;
+ skb->data[3] &= X25_EXT_M_BIT;
+ skb->data[3] |= (x25->vr << 1) & 0xFE;
+ } else {
+ skb->data[2] &= X25_STD_M_BIT;
+ skb->data[2] |= (x25->vs << 1) & 0x0E;
+ skb->data[2] |= (x25->vr << 5) & 0xE0;
+ }
+
+ x25_transmit_link(skb, x25->neighbour);
+}
+
+void x25_kick(struct sock *sk)
+{
+ struct sk_buff *skb, *skbn;
+ unsigned short start, end;
+ int modulus;
+ struct x25_sock *x25 = x25_sk(sk);
+
+ if (x25->state != X25_STATE_3)
+ return;
+
+ /*
+ * Transmit interrupt data.
+ */
+ if (!x25->intflag && skb_peek(&x25->interrupt_out_queue) != NULL) {
+ x25->intflag = 1;
+ skb = skb_dequeue(&x25->interrupt_out_queue);
+ x25_transmit_link(skb, x25->neighbour);
+ }
+
+ if (x25->condition & X25_COND_PEER_RX_BUSY)
+ return;
+
+ if (!skb_peek(&sk->sk_write_queue))
+ return;
+
+ modulus = x25->neighbour->extended ? X25_EMODULUS : X25_SMODULUS;
+
+ start = skb_peek(&x25->ack_queue) ? x25->vs : x25->va;
+ end = (x25->va + x25->facilities.winsize_out) % modulus;
+
+ if (start == end)
+ return;
+
+ x25->vs = start;
+
+ /*
+ * Transmit data until either we're out of data to send or
+ * the window is full.
+ */
+
+ 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.
+ */
+ x25_send_iframe(sk, skbn);
+
+ x25->vs = (x25->vs + 1) % modulus;
+
+ /*
+ * Requeue the original data frame.
+ */
+ skb_queue_tail(&x25->ack_queue, skb);
+
+ } while (x25->vs != end &&
+ (skb = skb_dequeue(&sk->sk_write_queue)) != NULL);
+
+ x25->vl = x25->vr;
+ x25->condition &= ~X25_COND_ACK_PENDING;
+
+ x25_stop_timer(sk);
+}
+
+/*
+ * The following routines are taken from page 170 of the 7th ARRL Computer
+ * Networking Conference paper, as is the whole state machine.
+ */
+
+void x25_enquiry_response(struct sock *sk)
+{
+ struct x25_sock *x25 = x25_sk(sk);
+
+ if (x25->condition & X25_COND_OWN_RX_BUSY)
+ x25_write_internal(sk, X25_RNR);
+ else
+ x25_write_internal(sk, X25_RR);
+
+ x25->vl = x25->vr;
+ x25->condition &= ~X25_COND_ACK_PENDING;
+
+ x25_stop_timer(sk);
+}