[unix-history] / sys / netccitt / hd_output.c

/*
 * Copyright (c) University of British Columbia, 1984
 * Copyright (c) 1990 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * the Laboratory for Computation Vision and the Computer Science Department
 * of the University of British Columbia.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	@(#)hd_output.c	7.6 (Berkeley) 5/29/91
 */

#include "param.h"
#include "systm.h"
#include "mbuf.h"
#include "domain.h"
#include "socket.h"
#include "syslog.h"
#include "protosw.h"
#include "errno.h"
#include "time.h"
#include "kernel.h"

#include "../net/if.h"

#include "hdlc.h"
#include "hd_var.h"
#include "x25.h"

/*
 *      HDLC OUTPUT INTERFACE
 *
 *      This routine is called when the X.25 packet layer output routine
 *      has a information frame (iframe)  to write.   It is  also called 
 *      by the input and control routines of the HDLC layer.
 */

hd_output (hdp, m0)
register struct hdcb *hdp;
struct mbuf *m0;
{
	struct x25config *xcp;
	register struct mbuf *m = m0;
	int len;

	if (m == NULL)
		panic ("hd_output");
	if (m->m_flags & M_PKTHDR == 0)
		panic ("hd_output 2");

	if (hdp->hd_state != ABM) {
		m_freem (m);
		return;
	}

	/*
	 * Make room for the hdlc header either by prepending
	 * another mbuf, or by adjusting the offset and length
	 * of the first mbuf in the mbuf chain.
	 */

	M_PREPEND(m, HDHEADERLN, M_DONTWAIT);
	if (m == NULL)
		return;
	for (len = 0; m; m = m->m_next)
		len += m->m_len;
	m = m0;
	m->m_pkthdr.len = len;

	hd_append (&hdp->hd_txq, m);
	hd_start (hdp);
}

hd_start (hdp)
register struct hdcb *hdp;
{
	register struct mbuf *m;

	/* 
	 * The iframe is only transmitted if all these conditions are FALSE.
	 * The iframe remains queued (hdp->hd_txq) however and will be
	 * transmitted as soon as these conditions are cleared.
	 */

	while (!(hdp->hd_condition & (TIMER_RECOVERY_CONDITION | REMOTE_RNR_CONDITION | REJ_CONDITION))) {
		if (hdp->hd_vs == (hdp->hd_lastrxnr + hdp->hd_xcp->xc_lwsize) % MODULUS) {

			/* We have now exceeded the  maximum  number  of 
			   outstanding iframes. Therefore,  we must wait 
			   until  at least  one is acknowledged if this 
			   condition  is not  turned off before we are
			   requested to write another iframe. */
			hdp->hd_window_condition++;
			break;
		}

		/* hd_remove top iframe from transmit queue. */
		if ((m = hd_remove (&hdp->hd_txq)) == NULL)
			break;

		hd_send_iframe (hdp, m, POLLOFF);
	}
}

/* 
 *  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.  It
 *  also  starts the  acknowledgement  timer and keeps  the iframe in the
 *  Retransmit queue (Retxq) just in case  we have to do this again.
 *
 *  Note: This routine is also called from hd_input.c when retransmission
 *       of old frames is required.
 */

hd_send_iframe (hdp, buf, poll_bit)
register struct hdcb *hdp;
register struct mbuf *buf;
int poll_bit;
{
	register struct Hdlc_iframe *iframe;
	struct mbuf *m;

	KILL_TIMER (hdp);

	if (buf == 0) {
		printf ("hd_send_iframe: zero arg\n");
#ifdef HDLCDEBUG
		hd_status (hdp);
		hd_dumptrace (hdp);
#endif
		hdp->hd_vs = (hdp->hd_vs + 7) % MODULUS;
		return;
	}
	iframe = mtod (buf, struct Hdlc_iframe *);

	iframe -> hdlc_0 = 0;
	iframe -> nr = hdp->hd_vr;
	iframe -> pf = poll_bit;
	iframe -> ns = hdp->hd_vs;
	iframe -> address = ADDRESS_B;
	hdp->hd_lasttxnr = hdp->hd_vr;
	hdp->hd_rrtimer = 0;

	if (hdp->hd_vs == hdp->hd_retxqi) {
		/* Check for retransmissions. */
		/* Put iframe only once in the Retransmission queue. */
		hdp->hd_retxq[hdp->hd_retxqi] = buf;
		hdp->hd_retxqi = (hdp->hd_retxqi + 1) % MODULUS;
		hdp->hd_iframes_out++;
	}

	hdp->hd_vs = (hdp->hd_vs + 1) % MODULUS;

	hd_trace (hdp, TX, (struct Hdlc_frame *)iframe);

	/* Write buffer on device. */
	m = hdp->hd_dontcopy ? buf : m_copy(buf, 0, (int)M_COPYALL);
	if (m == 0) {
		printf("hdlc: out of mbufs\n");
		return;
	}
	(*hdp->hd_output)(hdp, m);
	SET_TIMER (hdp);
}

hd_ifoutput(hdp, m)
register struct mbuf *m;
register struct hdcb *hdp;
{
	/*
	 * Queue message on interface, and start output if interface
	 * not yet active.
	 */
	register struct ifnet *ifp = hdp->hd_ifp;
	int s = splimp();

	if (IF_QFULL(&ifp->if_snd)) {
		IF_DROP(&ifp->if_snd);
	    /* printf("%s%d: HDLC says OK to send but queue full, may hang\n",
			ifp->if_name, ifp->if_unit);*/
		m_freem(m);
	} else {
		IF_ENQUEUE(&ifp->if_snd, m);
		if ((ifp->if_flags & IFF_OACTIVE) == 0)
			(*ifp->if_start)(ifp);
	}
	splx(s);
}


/* 
 *  This routine gets control when the timer expires because we have not
 *  received an acknowledgement for a iframe.
 */

hd_resend_iframe (hdp)
register struct hdcb *hdp;
{

	if (hdp->hd_retxcnt++ < hd_n2) {
		if (!(hdp->hd_condition & TIMER_RECOVERY_CONDITION)) {
			hdp->hd_xx = hdp->hd_vs;
			hdp->hd_condition |= TIMER_RECOVERY_CONDITION;
		}

		hdp->hd_vs = hdp->hd_lastrxnr;
		hd_send_iframe (hdp, hdp->hd_retxq[hdp->hd_vs], POLLON);
	} else {
		/* At this point we have not received a RR even after N2
		   retries - attempt to reset link. */

		hd_initvars (hdp);
		hd_writeinternal (hdp, SABM, POLLOFF);
		hdp->hd_state = WAIT_UA;
		SET_TIMER (hdp);
		hd_message (hdp, "Timer recovery failed: link down");
		(void) pk_ctlinput (PRC_LINKDOWN, hdp->hd_pkp);
	}
}
Commit	Line	Data
15637ed4 RG	1	/*
	2	* Copyright (c) University of British Columbia, 1984
	3	* Copyright (c) 1990 The Regents of the University of California.
	4	* All rights reserved.
	5	*
	6	* This code is derived from software contributed to Berkeley by
	7	* the Laboratory for Computation Vision and the Computer Science Department
	8	* of the University of British Columbia.
	9	*
	10	* Redistribution and use in source and binary forms, with or without
	11	* modification, are permitted provided that the following conditions
	12	* are met:
	13	* 1. Redistributions of source code must retain the above copyright
	14	* notice, this list of conditions and the following disclaimer.
	15	* 2. Redistributions in binary form must reproduce the above copyright
	16	* notice, this list of conditions and the following disclaimer in the
	17	* documentation and/or other materials provided with the distribution.
	18	* 3. All advertising materials mentioning features or use of this software
	19	* must display the following acknowledgement:
	20	* This product includes software developed by the University of
	21	* California, Berkeley and its contributors.
	22	* 4. Neither the name of the University nor the names of its contributors
	23	* may be used to endorse or promote products derived from this software
	24	* without specific prior written permission.
	25	*
	26	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	27	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	28	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	29	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	30	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	31	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	32	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	33	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	34	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	35	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	36	* SUCH DAMAGE.
	37	*
	38	* @(#)hd_output.c 7.6 (Berkeley) 5/29/91
	39	*/
	40
	41	#include "param.h"
	42	#include "systm.h"
	43	#include "mbuf.h"
	44	#include "domain.h"
	45	#include "socket.h"
	46	#include "syslog.h"
	47	#include "protosw.h"
	48	#include "errno.h"
	49	#include "time.h"
	50	#include "kernel.h"
	51
	52	#include "../net/if.h"
	53
	54	#include "hdlc.h"
	55	#include "hd_var.h"
	56	#include "x25.h"
	57
	58	/*
	59	* HDLC OUTPUT INTERFACE
	60	*
	61	* This routine is called when the X.25 packet layer output routine
	62	* has a information frame (iframe) to write. It is also called
	63	* by the input and control routines of the HDLC layer.
	64	*/
65
66	hd_output (hdp, m0)
67	register struct hdcb *hdp;
68	struct mbuf *m0;
69	{
70	struct x25config *xcp;
71	register struct mbuf *m = m0;
72	int len;
73
74	if (m == NULL)
75	panic ("hd_output");
76	if (m->m_flags & M_PKTHDR == 0)
77	panic ("hd_output 2");
78
79	if (hdp->hd_state != ABM) {
80	m_freem (m);
81	return;
82	}
83
84	/*
85	* Make room for the hdlc header either by prepending
86	* another mbuf, or by adjusting the offset and length
87	* of the first mbuf in the mbuf chain.
88	*/
89
90	M_PREPEND(m, HDHEADERLN, M_DONTWAIT);
91	if (m == NULL)
92	return;
93	for (len = 0; m; m = m->m_next)
94	len += m->m_len;
95	m = m0;
96	m->m_pkthdr.len = len;
97
98	hd_append (&hdp->hd_txq, m);
99	hd_start (hdp);
100	}
101
102	hd_start (hdp)
103	register struct hdcb *hdp;
104	{
105	register struct mbuf *m;
106
107	/*
108	* The iframe is only transmitted if all these conditions are FALSE.
109	* The iframe remains queued (hdp->hd_txq) however and will be
110	* transmitted as soon as these conditions are cleared.
111	*/
112
113	while (!(hdp->hd_condition & (TIMER_RECOVERY_CONDITION \| REMOTE_RNR_CONDITION \| REJ_CONDITION))) {
114	if (hdp->hd_vs == (hdp->hd_lastrxnr + hdp->hd_xcp->xc_lwsize) % MODULUS) {
115
116	/* We have now exceeded the maximum number of
117	outstanding iframes. Therefore, we must wait
118	until at least one is acknowledged if this
119	condition is not turned off before we are
120	requested to write another iframe. */
121	hdp->hd_window_condition++;
122	break;
123	}
124
125	/* hd_remove top iframe from transmit queue. */
126	if ((m = hd_remove (&hdp->hd_txq)) == NULL)
127	break;
128
129	hd_send_iframe (hdp, m, POLLOFF);
130	}
131	}
132
133	/*
134	* This procedure is passed a buffer descriptor for an iframe. It builds
135	* the rest of the control part of the frame and then writes it out. It
136	* also starts the acknowledgement timer and keeps the iframe in the
137	* Retransmit queue (Retxq) just in case we have to do this again.
138	*
139	* Note: This routine is also called from hd_input.c when retransmission
140	* of old frames is required.
141	*/
142
143	hd_send_iframe (hdp, buf, poll_bit)
144	register struct hdcb *hdp;
145	register struct mbuf *buf;
146	int poll_bit;
147	{
148	register struct Hdlc_iframe *iframe;
149	struct mbuf *m;
150
151	KILL_TIMER (hdp);
152
153	if (buf == 0) {
154	printf ("hd_send_iframe: zero arg\n");
155	#ifdef HDLCDEBUG
156	hd_status (hdp);
157	hd_dumptrace (hdp);
158	#endif
159	hdp->hd_vs = (hdp->hd_vs + 7) % MODULUS;
160	return;
161	}
162	iframe = mtod (buf, struct Hdlc_iframe *);
163
164	iframe -> hdlc_0 = 0;
165	iframe -> nr = hdp->hd_vr;
166	iframe -> pf = poll_bit;
167	iframe -> ns = hdp->hd_vs;
168	iframe -> address = ADDRESS_B;
169	hdp->hd_lasttxnr = hdp->hd_vr;
170	hdp->hd_rrtimer = 0;
171
172	if (hdp->hd_vs == hdp->hd_retxqi) {
173	/* Check for retransmissions. */
174	/* Put iframe only once in the Retransmission queue. */
175	hdp->hd_retxq[hdp->hd_retxqi] = buf;
176	hdp->hd_retxqi = (hdp->hd_retxqi + 1) % MODULUS;
177	hdp->hd_iframes_out++;
178	}
179
180	hdp->hd_vs = (hdp->hd_vs + 1) % MODULUS;
181
182	hd_trace (hdp, TX, (struct Hdlc_frame *)iframe);
183
184	/* Write buffer on device. */
185	m = hdp->hd_dontcopy ? buf : m_copy(buf, 0, (int)M_COPYALL);
186	if (m == 0) {
187	printf("hdlc: out of mbufs\n");
188	return;
189	}
190	(*hdp->hd_output)(hdp, m);
191	SET_TIMER (hdp);
192	}
193
194	hd_ifoutput(hdp, m)
195	register struct mbuf *m;
196	register struct hdcb *hdp;
197	{
198	/*
199	* Queue message on interface, and start output if interface
200	* not yet active.
201	*/
202	register struct ifnet *ifp = hdp->hd_ifp;
203	int s = splimp();
204
205	if (IF_QFULL(&ifp->if_snd)) {
206	IF_DROP(&ifp->if_snd);
207	/* printf("%s%d: HDLC says OK to send but queue full, may hang\n",
208	ifp->if_name, ifp->if_unit);*/
209	m_freem(m);
210	} else {
211	IF_ENQUEUE(&ifp->if_snd, m);
212	if ((ifp->if_flags & IFF_OACTIVE) == 0)
213	(*ifp->if_start)(ifp);
214	}
215	splx(s);
216	}
217
218
219	/*
220	* This routine gets control when the timer expires because we have not
221	* received an acknowledgement for a iframe.
222	*/
223
224	hd_resend_iframe (hdp)
225	register struct hdcb *hdp;
226	{
227
228	if (hdp->hd_retxcnt++ < hd_n2) {
229	if (!(hdp->hd_condition & TIMER_RECOVERY_CONDITION)) {
230	hdp->hd_xx = hdp->hd_vs;
231	hdp->hd_condition \|= TIMER_RECOVERY_CONDITION;
232	}
233
234	hdp->hd_vs = hdp->hd_lastrxnr;
235	hd_send_iframe (hdp, hdp->hd_retxq[hdp->hd_vs], POLLON);
236	} else {
237	/* At this point we have not received a RR even after N2
238	retries - attempt to reset link. */
239
240	hd_initvars (hdp);
241	hd_writeinternal (hdp, SABM, POLLOFF);
242	hdp->hd_state = WAIT_UA;
243	SET_TIMER (hdp);
244	hd_message (hdp, "Timer recovery failed: link down");
245	(void) pk_ctlinput (PRC_LINKDOWN, hdp->hd_pkp);
246	}
247	}