diff --git a/net/x25/x25_subr.c b/net/x25/x25_subr.c
new file mode 100644
index 0000000..183fea3
--- /dev/null
+++ b/net/x25/x25_subr.c
@@ -0,0 +1,374 @@
+/*
+ *	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	  Centralised disconnection processing.
+ *	mar/20/00	Daniela Squassoni Disabling/enabling of facilities
+ *					  negotiation.
+ *	jun/24/01	Arnaldo C. Melo	  use skb_queue_purge, cleanups
+ */
+
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <net/tcp.h>
+#include <net/x25.h>
+
+/*
+ *	This routine purges all of the queues of frames.
+ */
+void x25_clear_queues(struct sock *sk)
+{
+	struct x25_sock *x25 = x25_sk(sk);
+
+	skb_queue_purge(&sk->sk_write_queue);
+	skb_queue_purge(&x25->ack_queue);
+	skb_queue_purge(&x25->interrupt_in_queue);
+	skb_queue_purge(&x25->interrupt_out_queue);
+	skb_queue_purge(&x25->fragment_queue);
+}
+
+
+/*
+ * This routine purges the input queue of those frames that have been
+ * acknowledged. This replaces the boxes labelled "V(a) <- N(r)" on the
+ * SDL diagram.
+*/
+void x25_frames_acked(struct sock *sk, unsigned short nr)
+{
+	struct sk_buff *skb;
+	struct x25_sock *x25 = x25_sk(sk);
+	int modulus = x25->neighbour->extended ? X25_EMODULUS : X25_SMODULUS;
+
+	/*
+	 * Remove all the ack-ed frames from the ack queue.
+	 */
+	if (x25->va != nr)
+		while (skb_peek(&x25->ack_queue) && x25->va != nr) {
+			skb = skb_dequeue(&x25->ack_queue);
+			kfree_skb(skb);
+			x25->va = (x25->va + 1) % modulus;
+		}
+}
+
+void x25_requeue_frames(struct sock *sk)
+{
+	struct sk_buff *skb, *skb_prev = NULL;
+
+	/*
+	 * Requeue all the un-ack-ed frames on the output queue to be picked
+	 * up by x25_kick. This arrangement handles the possibility of an empty
+	 * output queue.
+	 */
+	while ((skb = skb_dequeue(&x25_sk(sk)->ack_queue)) != NULL) {
+		if (!skb_prev)
+			skb_queue_head(&sk->sk_write_queue, skb);
+		else
+			skb_append(skb_prev, skb);
+		skb_prev = skb;
+	}
+}
+
+/*
+ *	Validate that the value of nr is between va and vs. Return true or
+ *	false for testing.
+ */
+int x25_validate_nr(struct sock *sk, unsigned short nr)
+{
+	struct x25_sock *x25 = x25_sk(sk);
+	unsigned short vc = x25->va;
+	int modulus = x25->neighbour->extended ? X25_EMODULUS : X25_SMODULUS;
+
+	while (vc != x25->vs) {
+		if (nr == vc)
+			return 1;
+		vc = (vc + 1) % modulus;
+	}
+
+	return nr == x25->vs ? 1 : 0;
+}
+
+/*
+ *  This routine is called when the packet layer internally generates a
+ *  control frame.
+ */
+void x25_write_internal(struct sock *sk, int frametype)
+{
+	struct x25_sock *x25 = x25_sk(sk);
+	struct sk_buff *skb;
+	unsigned char  *dptr;
+	unsigned char  facilities[X25_MAX_FAC_LEN];
+	unsigned char  addresses[1 + X25_ADDR_LEN];
+	unsigned char  lci1, lci2;
+	/*
+	 *	Default safe frame size.
+	 */
+	int len = X25_MAX_L2_LEN + X25_EXT_MIN_LEN;
+
+	/*
+	 *	Adjust frame size.
+	 */
+	switch (frametype) {
+		case X25_CALL_REQUEST:
+			len += 1 + X25_ADDR_LEN + X25_MAX_FAC_LEN +
+			       X25_MAX_CUD_LEN;
+			break;
+		case X25_CALL_ACCEPTED:
+			len += 1 + X25_MAX_FAC_LEN + X25_MAX_CUD_LEN;
+			break;
+		case X25_CLEAR_REQUEST:
+		case X25_RESET_REQUEST:
+			len += 2;
+			break;
+		case X25_RR:
+		case X25_RNR:
+		case X25_REJ:
+		case X25_CLEAR_CONFIRMATION:
+		case X25_INTERRUPT_CONFIRMATION:
+		case X25_RESET_CONFIRMATION:
+			break;
+		default:
+			printk(KERN_ERR "X.25: invalid frame type %02X\n",
+			       frametype);
+			return;
+	}
+
+	if ((skb = alloc_skb(len, GFP_ATOMIC)) == NULL)
+		return;
+
+	/*
+	 *	Space for Ethernet and 802.2 LLC headers.
+	 */
+	skb_reserve(skb, X25_MAX_L2_LEN);
+
+	/*
+	 *	Make space for the GFI and LCI, and fill them in.
+	 */
+	dptr = skb_put(skb, 2);
+
+	lci1 = (x25->lci >> 8) & 0x0F;
+	lci2 = (x25->lci >> 0) & 0xFF;
+
+	if (x25->neighbour->extended) {
+		*dptr++ = lci1 | X25_GFI_EXTSEQ;
+		*dptr++ = lci2;
+	} else {
+		*dptr++ = lci1 | X25_GFI_STDSEQ;
+		*dptr++ = lci2;
+	}
+
+	/*
+	 *	Now fill in the frame type specific information.
+	 */
+	switch (frametype) {
+
+		case X25_CALL_REQUEST:
+			dptr    = skb_put(skb, 1);
+			*dptr++ = X25_CALL_REQUEST;
+			len     = x25_addr_aton(addresses, &x25->dest_addr,
+						&x25->source_addr);
+			dptr    = skb_put(skb, len);
+			memcpy(dptr, addresses, len);
+			len     = x25_create_facilities(facilities,
+							&x25->facilities,
+					     x25->neighbour->global_facil_mask);
+			dptr    = skb_put(skb, len);
+			memcpy(dptr, facilities, len);
+			dptr = skb_put(skb, x25->calluserdata.cudlength);
+			memcpy(dptr, x25->calluserdata.cuddata,
+			       x25->calluserdata.cudlength);
+			x25->calluserdata.cudlength = 0;
+			break;
+
+		case X25_CALL_ACCEPTED:
+			dptr    = skb_put(skb, 2);
+			*dptr++ = X25_CALL_ACCEPTED;
+			*dptr++ = 0x00;		/* Address lengths */
+			len     = x25_create_facilities(facilities,
+							&x25->facilities,
+							x25->vc_facil_mask);
+			dptr    = skb_put(skb, len);
+			memcpy(dptr, facilities, len);
+			dptr = skb_put(skb, x25->calluserdata.cudlength);
+			memcpy(dptr, x25->calluserdata.cuddata,
+			       x25->calluserdata.cudlength);
+			x25->calluserdata.cudlength = 0;
+			break;
+
+		case X25_CLEAR_REQUEST:
+		case X25_RESET_REQUEST:
+			dptr    = skb_put(skb, 3);
+			*dptr++ = frametype;
+			*dptr++ = 0x00;		/* XXX */
+			*dptr++ = 0x00;		/* XXX */
+			break;
+
+		case X25_RR:
+		case X25_RNR:
+		case X25_REJ:
+			if (x25->neighbour->extended) {
+				dptr     = skb_put(skb, 2);
+				*dptr++  = frametype;
+				*dptr++  = (x25->vr << 1) & 0xFE;
+			} else {
+				dptr     = skb_put(skb, 1);
+				*dptr    = frametype;
+				*dptr++ |= (x25->vr << 5) & 0xE0;
+			}
+			break;
+
+		case X25_CLEAR_CONFIRMATION:
+		case X25_INTERRUPT_CONFIRMATION:
+		case X25_RESET_CONFIRMATION:
+			dptr  = skb_put(skb, 1);
+			*dptr = frametype;
+			break;
+	}
+
+	x25_transmit_link(skb, x25->neighbour);
+}
+
+/*
+ *	Unpick the contents of the passed X.25 Packet Layer frame.
+ */
+int x25_decode(struct sock *sk, struct sk_buff *skb, int *ns, int *nr, int *q,
+	       int *d, int *m)
+{
+	struct x25_sock *x25 = x25_sk(sk);
+	unsigned char *frame = skb->data;
+
+	*ns = *nr = *q = *d = *m = 0;
+
+	switch (frame[2]) {
+		case X25_CALL_REQUEST:
+		case X25_CALL_ACCEPTED:
+		case X25_CLEAR_REQUEST:
+		case X25_CLEAR_CONFIRMATION:
+		case X25_INTERRUPT:
+		case X25_INTERRUPT_CONFIRMATION:
+		case X25_RESET_REQUEST:
+		case X25_RESET_CONFIRMATION:
+		case X25_RESTART_REQUEST:
+		case X25_RESTART_CONFIRMATION:
+		case X25_REGISTRATION_REQUEST:
+		case X25_REGISTRATION_CONFIRMATION:
+		case X25_DIAGNOSTIC:
+			return frame[2];
+	}
+
+	if (x25->neighbour->extended) {
+		if (frame[2] == X25_RR  ||
+		    frame[2] == X25_RNR ||
+		    frame[2] == X25_REJ) {
+			*nr = (frame[3] >> 1) & 0x7F;
+			return frame[2];
+		}
+	} else {
+		if ((frame[2] & 0x1F) == X25_RR  ||
+		    (frame[2] & 0x1F) == X25_RNR ||
+		    (frame[2] & 0x1F) == X25_REJ) {
+			*nr = (frame[2] >> 5) & 0x07;
+			return frame[2] & 0x1F;
+		}
+	}
+
+	if (x25->neighbour->extended) {
+		if ((frame[2] & 0x01) == X25_DATA) {
+			*q  = (frame[0] & X25_Q_BIT) == X25_Q_BIT;
+			*d  = (frame[0] & X25_D_BIT) == X25_D_BIT;
+			*m  = (frame[3] & X25_EXT_M_BIT) == X25_EXT_M_BIT;
+			*nr = (frame[3] >> 1) & 0x7F;
+			*ns = (frame[2] >> 1) & 0x7F;
+			return X25_DATA;
+		}
+	} else {
+		if ((frame[2] & 0x01) == X25_DATA) {
+			*q  = (frame[0] & X25_Q_BIT) == X25_Q_BIT;
+			*d  = (frame[0] & X25_D_BIT) == X25_D_BIT;
+			*m  = (frame[2] & X25_STD_M_BIT) == X25_STD_M_BIT;
+			*nr = (frame[2] >> 5) & 0x07;
+			*ns = (frame[2] >> 1) & 0x07;
+			return X25_DATA;
+		}
+	}
+
+	printk(KERN_DEBUG "X.25: invalid PLP frame %02X %02X %02X\n",
+	       frame[0], frame[1], frame[2]);
+
+	return X25_ILLEGAL;
+}
+
+void x25_disconnect(struct sock *sk, int reason, unsigned char cause,
+		    unsigned char diagnostic)
+{
+	struct x25_sock *x25 = x25_sk(sk);
+
+	x25_clear_queues(sk);
+	x25_stop_timer(sk);
+
+	x25->lci   = 0;
+	x25->state = X25_STATE_0;
+
+	x25->causediag.cause      = cause;
+	x25->causediag.diagnostic = diagnostic;
+
+	sk->sk_state     = TCP_CLOSE;
+	sk->sk_err       = reason;
+	sk->sk_shutdown |= SEND_SHUTDOWN;
+
+	if (!sock_flag(sk, SOCK_DEAD)) {
+		sk->sk_state_change(sk);
+		sock_set_flag(sk, SOCK_DEAD);
+	}
+}
+
+/*
+ * Clear an own-rx-busy condition and tell the peer about this, provided
+ * that there is a significant amount of free receive buffer space available.
+ */
+void x25_check_rbuf(struct sock *sk)
+{
+	struct x25_sock *x25 = x25_sk(sk);
+
+	if (atomic_read(&sk->sk_rmem_alloc) < (sk->sk_rcvbuf / 2) &&
+	    (x25->condition & X25_COND_OWN_RX_BUSY)) {
+		x25->condition &= ~X25_COND_OWN_RX_BUSY;
+		x25->condition &= ~X25_COND_ACK_PENDING;
+		x25->vl         = x25->vr;
+		x25_write_internal(sk, X25_RR);
+		x25_stop_timer(sk);
+	}
+}
+
+/*
+ * Compare 2 calluserdata structures, used to find correct listening sockets
+ * when call user data is used.
+ */
+int x25_check_calluserdata(struct x25_calluserdata *ours, struct x25_calluserdata *theirs)
+{
+	int i;
+	if (ours->cudlength != theirs->cudlength)
+		return 0;
+
+	for (i=0;i<ours->cudlength;i++) {
+		if (ours->cuddata[i] != theirs->cuddata[i]) {
+			return 0;
+		}
+	}
+	return 1;
+}
+