tp_emit.c

早期freebsd实现

				tpcb->tp_reneged = 1;
				IncStat(ts_lcdt_reduced);
				IFTRACE(D_CREDIT)
					tptraceTPCB(TPPTmisc, 
						"RENEG: olduwe newuwe lcredit rcvnxt",
						olduwe,
						tpcb->tp_sent_uwe, tpcb->tp_lcredit,
						tpcb->tp_rcvnxt);
				ENDTRACE
			}
			IFPERF(tpcb)
				/* new lwe is less than old uwe means we're
				 * acking before we received a whole window full
				 */
				if( SEQ_LT( tpcb, tpcb->tp_rcvnxt, olduwe) ) {
					/* tmp1 = number of pkts fewer than the full window */
					register int tmp1 = 
						(int) SEQ_SUB( tpcb, olduwe, tpcb->tp_rcvnxt);

					if(tmp1 > TP_PM_MAX)
						tmp1 = TP_PM_MAX;
					IncPStat( tpcb,  tps_ack_early[tmp1] );

					/* tmp1 = amt of new cdt we're advertising */
					tmp1 = SEQ_SUB( tpcb, seq, tpcb->tp_sent_rcvnxt);
					if(tmp1 > TP_PM_MAX )
						tmp1 = TP_PM_MAX;

					IncPStat( tpcb, 
							tps_cdt_acked [ tmp1 ]
							[ ((tpcb->tp_lcredit > TP_PM_MAX)?
								TP_PM_MAX:tpcb->tp_lcredit) ] );

				}
			ENDPERF

			IFTRACE(D_ACKSEND)
				tptraceTPCB(TPPTack, seq, tpcb->tp_lcredit, tpcb->tp_sent_uwe, 
					tpcb->tp_r_subseq, 0);
			ENDTRACE
			if (tpcb->tp_xtd_format) {
#ifdef BYTE_ORDER
				union seq_type seqeotX;

				seqeotX.s_seq = seq;
				seqeotX.s_eot = 0;
				hdr->tpdu_seqeotX = htonl(seqeotX.s_seqeot);
				hdr->tpdu_AKcdtX = htons(tpcb->tp_lcredit);
#else
				hdr->tpdu_cdt = 0; 
				hdr->tpdu_AKseqX = seq;
				hdr->tpdu_AKcdtX = tpcb->tp_lcredit;
#endif /* BYTE_ORDER */
			} else {
				hdr->tpdu_AKseq = seq;
				hdr->tpdu_AKcdt = tpcb->tp_lcredit;
			}
			if ((tpcb->tp_class == TP_CLASS_4) &&
				(tpcb->tp_reneged || acking_ooo)) {
				/* 
				 * Ack subsequence parameter req'd if WE reneged on 
				 * credit offered.  (ISO 8073, 12.2.3.8.2, p. 74)
				 */
				IFDEBUG(D_RENEG)
					printf("Adding subseq 0x%x\n", tpcb->tp_s_subseq);
				ENDDEBUG
				tpcb->tp_s_subseq++;
				/*
				 * add tmp subseq and do a htons on it.
				 */
				ADDOPTION(TPP_subseq, hdr, 
					sizeof(tpcb->tp_s_subseq), tpcb->tp_s_subseq);
			} else
				tpcb->tp_s_subseq = 0;

			if ( tpcb->tp_sendfcc || eot ) /* overloaded to mean SEND FCC */ {
				/* 
				 * Rules for sending FCC ("should" send when) :
				 * %a) received an ack from peer with NO NEWS whatsoever,
				 *  	and it did not contain an FCC
				 * 	b) received an ack from peer that opens its closed window.
				 * 	c) received an ack from peer after it reneged on its
				 *		offered credit, AND this ack raises UWE but LWE is same
				 *		and below UWE at time of reneging (reduction)
				 * Now, ISO 8073 12.2.3.8.3 says
				 * that a retransmitted AK shall not contain the FCC
				 * parameter.  Now, how the hell you tell the difference 
				 * between a retransmitted ack and an ack that's sent in 
				 * response to a received ack, I don't know, because without
				 * any local activity, and w/o any received DTs, they
				 * will contain exactly the same credit/seq# information.
				 * Anyway, given that the "retransmission of acks"
				 * procedure (ISO 8073 12.2.3.8.3) is optional, and we
				 * don't do it (although the peer can't tell that), we 
				 * ignore this last rule.
				 *
				 * We send FCC for reasons a) and b) only. 
				 * To add reason c) would require a ridiculous amount of state.
				 * 
				 */
				u_short 	bogus[4]; /* lwe(32), subseq(16), cdt(16) */
				SeqNum		lwe;
				u_short		subseq, fcredit;

				tpcb->tp_sendfcc = 0;

				lwe = (SeqNum) htonl(tpcb->tp_snduna);
				subseq = htons(tpcb->tp_r_subseq);
				fcredit = htons(tpcb->tp_fcredit);

				bcopy((caddr_t) &lwe, (caddr_t)&bogus[0], sizeof(SeqNum));
				bcopy((caddr_t) &subseq, (caddr_t)&bogus[2], sizeof(u_short));
				bcopy((caddr_t) &fcredit, (caddr_t)&bogus[3], sizeof(u_short));

				IFTRACE(D_ACKSEND)
					tptraceTPCB(TPPTmisc, 
						"emit w/FCC: snduna r_subseq fcredit", 
						tpcb->tp_snduna, tpcb->tp_r_subseq,
						tpcb->tp_fcredit, 0);
				ENDTRACE

				IFDEBUG(D_ACKSEND)
					printf("Calling ADDOPTION 0x%x, 0x%x, 0x%x,0x%x\n",
						TPP_flow_cntl_conf, 
						hdr, sizeof(bogus), bogus[0]);
				ENDDEBUG
				ADDOPTION(TPP_flow_cntl_conf, hdr, sizeof(bogus), bogus[0]);
				IFDEBUG(D_ACKSEND)
					printf("after ADDOPTION hdr 0x%x hdr->tpdu_li 0x%x\n",
						hdr, hdr->tpdu_li);
					printf(
					"after ADDOPTION csum_offset 0x%x, hdr->tpdu_li 0x%x\n",
							csum_offset, hdr->tpdu_li);
				ENDDEBUG
					
			}
			tpcb->tp_reneged = 0;
			tpcb->tp_sent_rcvnxt = seq;
			if (tpcb->tp_fcredit == 0) {
				int timo = tpcb->tp_keepalive_ticks;
				if (tpcb->tp_rxtshift < TP_MAXRXTSHIFT)
					tpcb->tp_rxtshift++;
				timo = min(timo, ((int)tpcb->tp_dt_ticks) << tpcb->tp_rxtshift);
				tp_ctimeout(tpcb, TM_sendack, timo);
			} else
				tp_ctimeout(tpcb, TM_sendack, tpcb->tp_keepalive_ticks);
			IncStat(ts_AK_sent);
			IncPStat(tpcb, tps_AK_sent);
			IFDEBUG(D_ACKSEND)
				printf(
				"2 after rADDOPTION csum_offset 0x%x, hdr->tpdu_li 0x%x\n",
						csum_offset, hdr->tpdu_li);
			ENDDEBUG
			break;

		case ER_TPDU_type:
			hdr->tpdu_ERreason = eot; 
			hdr->tpdu_cdt = 0;
			/* no user data */
			data = (struct mbuf *)0;
			IncStat(ts_ER_sent);
			break;
		}

	}
	ASSERT( ((int)hdr->tpdu_li > 0) && ((int)hdr->tpdu_li < MLEN) );

	m->m_next = data;

	ASSERT( hdr->tpdu_li < MLEN ); /* leave this in */
	ASSERT( hdr->tpdu_li != 0 ); /* leave this in */

	m->m_len = hdr->tpdu_li ; 
	hdr->tpdu_li --; /* doesn't include the li field */

	datalen = m_datalen( m ); /* total len */

	ASSERT( datalen <= tpcb->tp_l_tpdusize ); /* may become a problem
				when CLNP is used; leave in here for the time being */
		IFDEBUG(D_ACKSEND)
			printf(
			"4 after rADDOPTION csum_offset 0x%x, hdr->tpdu_li 0x%x\n",
					csum_offset, hdr->tpdu_li);
		ENDDEBUG
	if( datalen > tpcb->tp_l_tpdusize ) {
		printf("data len 0x%x tpcb->tp_l_tpdusize 0x%x\n", 
			datalen, tpcb->tp_l_tpdusize);
	}
	IFDEBUG(D_EMIT)
		printf(
		"tp_emit before gen_csum m_len 0x%x, csum_offset 0x%x, datalen 0x%x\n",
		m->m_len, csum_offset, datalen);
	ENDDEBUG
	if( tpcb->tp_use_checksum || 
		(dutype == CR_TPDU_type && (tpcb->tp_class & TP_CLASS_4)) ) {
		iso_gen_csum(m, csum_offset, datalen);
	}

	IFDEBUG(D_EMIT)
	printf("tp_emit before tpxxx_output tpcb 0x%x, dutype 0x%x, datalen 0x%x\n",
		tpcb, dutype, datalen);
		dump_buf(mtod(m, caddr_t), datalen);
	ENDDEBUG

	IFPERF(tpcb)
		if( dutype == DT_TPDU_type ) {
			PStat(tpcb, Nb_to_ll) += (datalen - m->m_len);
			tpmeas( tpcb->tp_lref, TPtime_to_ll,  (struct timeval *)0,
				seq, PStat(tpcb, Nb_to_ll), (datalen - m->m_len));
		}
	ENDPERF

	IFTRACE(D_EMIT)
		tptraceTPCB(TPPTtpduout, dutype, hdr, hdr->tpdu_li+1, datalen, 0);
	ENDTRACE
	IFDEBUG(D_EMIT)
		printf("OUTPUT: tpcb 0x%x, isop 0x%x, so 0x%x\n",
			tpcb,  tpcb->tp_npcb,  tpcb->tp_sock);
	ENDDEBUG

	{ extern char tp_delay;

		if( tp_delay )
			if( tpcb->tp_use_checksum == 0 ) {
				register u_int i  = tp_delay;
				for (; i!= 0; i--)
					(void) iso_check_csum(m, datalen);
			}
	}
	ASSERT( m->m_len > 0 );
	error = (tpcb->tp_nlproto->nlp_output)(tpcb->tp_npcb, m, datalen,
		!tpcb->tp_use_checksum);
	IFDEBUG(D_EMIT)
		printf("OUTPUT: returned 0x%x\n", error);
	ENDDEBUG
	IFTRACE(D_EMIT)
		tptraceTPCB(TPPTmisc, 
			"tp_emit nlproto->output netservice returns datalen", 
			tpcb->tp_nlproto->nlp_output, tpcb->tp_netservice, error, datalen); 
	ENDTRACE
done:
	if (error) {
		if (dutype == AK_TPDU_type)
			tp_ctimeout(tpcb, TM_sendack, 1);
		if (error == E_CO_QFULL) {
			tp_quench(tpcb, PRC_QUENCH);
			return 0;
		}
	}
	return error;
}
/*
 * NAME:		tp_error_emit()
 * CALLED FROM:	tp_input() when a DR or ER is to be issued in
 * 		response to an input error.
 * FUNCTION and ARGUMENTS:
 * 		The error type is the first argument.
 * 		The argument (sref) is the source reference on the bad incoming tpdu,
 * 		and is used for a destination reference on the outgoing packet.
 * 		(faddr) and (laddr) are the foreign and local addresses for this 
 *		connection.
 * 		(erdata) is a ptr to the errant incoming tpdu, and is copied into the
 * 		outgoing ER, if an ER is to be issued.
 * 		(erlen)  is the number of octets of the errant tpdu that we should
 * 		try to copy.
 * 		(tpcb) is the pcb that describes the connection for which the bad tpdu
 * 		arrived.
 * RETURN VALUES:
 * 		0 OK
 *  	ENOBUFS
 *  	E* from net layer datagram output routine
 * SIDE EFFECTS:	
 *
 * NOTES:			
 */

int
tp_error_emit(error, sref, faddr, laddr, erdata, erlen, tpcb, cons_channel,
	dgout_routine)
	int				error;
	u_long			sref;
	struct sockaddr_iso *faddr, *laddr;
	struct mbuf 	*erdata;
	int 			erlen;
	struct tp_pcb 	*tpcb;
	caddr_t			cons_channel;
	int				(*dgout_routine)();
{
	int						dutype;
	int 					datalen = 0;
	register struct tpdu	*hdr; 
	register struct mbuf	*m;
	int						csum_offset;

	IFTRACE(D_ERROR_EMIT)
		tptrace(TPPTmisc, "tp_error_emit error sref tpcb erlen", 
			error, sref, tpcb, erlen);
	ENDTRACE
	IFDEBUG(D_ERROR_EMIT)
		printf(
		"tp_error_emit error 0x%x sref 0x%x tpcb 0x%x erlen 0x%x chan 0x%x\n", 
			error, sref, tpcb, erlen, cons_channel);
	ENDDEBUG

	MGET(m, M_DONTWAIT, TPMT_TPHDR); 
	if (m == NULL) {
		return ENOBUFS;
	}
	m->m_len = sizeof(struct tpdu);
	m->m_act = MNULL;

	hdr = mtod(m, struct tpdu *);

	IFDEBUG(D_ERROR_EMIT)
		printf("[error 0x%x] [error&0xff  0x%x] [(char)error 0x%x]\n",
			error, error&0xff, (char)error);
	ENDDEBUG


	if (error & TP_ERROR_SNDC)
		dutype = DC_TPDU_type;
	else if (error & 0x40) {
		error &= ~0x40;
		dutype = ER_TPDU_type;
	} else
		dutype = DR_TPDU_type;
	error &= 0xff;

	hdr->tpdu_type = dutype;
	hdr->tpdu_cdt = 0;

	switch( dutype ) {

	case DC_TPDU_type:
		IncStat(ts_DC_sent);
		hdr->tpdu_li = 6;
		hdr->tpdu_DCdref = htons(sref);
		hdr->tpdu_DCsref = tpcb ? htons(tpcb->tp_lref) : 0;
		IFDEBUG(D_ERROR_EMIT)
			printf("DC case:\n");
			dump_buf( hdr, 6);
		ENDDEBUG
		/* forget the add'l information variable part */
		break;

	case DR_TPDU_type:
		IncStat(ts_DR_sent);
		hdr->tpdu_li = 7;
		hdr->tpdu_DRdref = htons(sref);
		hdr->tpdu_DRsref = 0;
		hdr->tpdu_DRreason = (char)error;
		IFDEBUG(D_ERROR_EMIT)
			printf("DR case:\n");
			dump_buf( hdr, 7);
		ENDDEBUG
		/* forget the add'l information variable part */
		break;

	case ER_TPDU_type:
		IncStat(ts_ER_sent);
		hdr->tpdu_li = 5; 
		hdr->tpdu_ERreason = (char)error;
		hdr->tpdu_ERdref = htons(sref);
		break;

	default:
		ASSERT(0);
		printf("TP PANIC: bad dutype 0x%x\n", dutype);
	}

	if(tpcb)
		if( tpcb->tp_use_checksum ) {
			ADDOPTION(TPP_checksum, hdr, 2, csum_offset /* dummy argument */); 
			csum_offset =  hdr->tpdu_li - 2;
		}

	ASSERT( hdr->tpdu_li < MLEN ); 

	if (dutype == ER_TPDU_type) {
		/* copy the errant tpdu into another 'variable part' */
		register caddr_t P;

		IFTRACE(D_ERROR_EMIT)
			tptrace(TPPTmisc, "error_emit ER len tpduli", erlen, hdr->tpdu_li,
				0,0);
		ENDTRACE
		IFDEBUG(D_ERROR_EMIT)
			printf("error_emit ER len 0x%x tpduli 0x%x\n", erlen, hdr->tpdu_li);
		ENDDEBUG

		/* copy at most as many octets for which you have room */
		if (erlen + hdr->tpdu_li + 2 > TP_MAX_HEADER_LEN)
			erlen = TP_MAX_HEADER_LEN - hdr->tpdu_li - 2;
			
		/* add the "invalid tpdu" parameter : required in class 0 */
		P = (caddr_t)hdr + (int)(hdr->tpdu_li);
		vbptr(P)->tpv_code =  TPP_invalid_tpdu; /* parameter code */
		vbptr(P)->tpv_len = erlen;	/* parameter length */
		m->m_len = hdr->tpdu_li + 2; /* 1 for code, 1 for length */

		/* tp_input very likely handed us an mbuf chain w/ nothing in
		 * the first mbuf and the data following the empty mbuf
		 */
		if(erdata->m_len == 0) {
			erdata = m_free(erdata); /* returns the next mbuf on the chain */
		}
		/*
		 * copy only up to the bad octet
		 * (or max that will fit in a header
		 */
		m->m_next = m_copy(erdata, 0, erlen);
		hdr->tpdu_li += erlen + 2; 
		m_freem(erdata);
	} else {
		IFDEBUG(D_ERROR_EMIT)
			printf("error_emit DR error tpduli 0x%x\n", error, hdr->tpdu_li);
			dump_buf( (char *)hdr, hdr->tpdu_li );
		ENDDEBUG
		m->m_len = hdr->tpdu_li ;
		m_freem(erdata);
	}

	hdr->tpdu_li --;
	IFTRACE(D_ERROR_EMIT)
		tptrace(TPPTtpduout, 2, hdr, hdr->tpdu_li+1, 0, 0);
	ENDTRACE

	datalen = m_datalen( m);
	if (tpcb) {
		if( tpcb->tp_use_checksum ) {
			IFTRACE(D_ERROR_EMIT)
				tptrace(TPPTmisc, "before gen csum datalen", datalen,0,0,0);
			ENDTRACE
			IFDEBUG(D_ERROR_EMIT)
				printf("before gen csum datalen 0x%x, csum_offset 0x%x\n", 
					datalen, csum_offset);
			ENDDEBUG

			iso_gen_csum(m, csum_offset, datalen);
		}

		IFDEBUG(D_ERROR_EMIT)
			printf("OUTPUT: tpcb 0x%x, isop 0x%x, so 0x%x\n",
				tpcb,  tpcb->tp_npcb,  tpcb->tp_sock);
		ENDDEBUG
	}
	if (cons_channel) {
#ifdef TPCONS
		struct pklcd *lcp = (struct pklcd *)cons_channel;
		struct isopcb *isop = (struct isopcb *)lcp->lcd_upnext;

		tpcons_dg_output(cons_channel, m, datalen);
		/* was if (tpcb == 0) iso_pcbdetach(isop); */
		/* but other side may want to try again over same VC,
		   so, we'll depend on him closing it, but in case it gets forgotten
		   we'll mark it for garbage collection */
		lcp->lcd_flags |= X25_DG_CIRCUIT;
		IFDEBUG(D_ERROR_EMIT)
			printf("OUTPUT: dutype 0x%x channel 0x%x\n",
				dutype, cons_channel);
		ENDDEBUG
#else
		printf("TP panic! cons channel 0x%x but not cons configured\n",
			cons_channel);
#endif
	} else if (tpcb) {

		IFDEBUG(D_ERROR_EMIT)
			printf("tp_error_emit 1 sending DG: Laddr\n");
			dump_addr((struct sockaddr *)laddr);
			printf("Faddr\n");
			dump_addr((struct sockaddr *)faddr);
		ENDDEBUG
		return (tpcb->tp_nlproto->nlp_dgoutput)(
			&laddr->siso_addr, 
			&faddr->siso_addr, 
			m, datalen, 
					/* no route */	(caddr_t)0, !tpcb->tp_use_checksum); 
	} else if (dgout_routine) {
			IFDEBUG(D_ERROR_EMIT)
				printf("tp_error_emit sending DG: Laddr\n");
				dump_addr((struct sockaddr *)laddr);
				printf("Faddr\n");
				dump_addr((struct sockaddr *)faddr);
			ENDDEBUG
				return (*dgout_routine)( &laddr->siso_addr, &faddr->siso_addr, 
					m, datalen, /* no route */ 
					(caddr_t)0, /* nochecksum==false */0);
	} else {
			IFDEBUG(D_ERROR_EMIT)
				printf("tp_error_emit DROPPING \n", m);
			ENDDEBUG
			IncStat(ts_send_drop);
			m_freem(m);
			return 0;
	}
}