tp_input.c

早期freebsd实现

 *
 * NOTE:
 *  The initial value of acktime is 2 so that we will never
 *  have a 0 value for tp_peer_acktime.  It gets used in the
 *  computation of the retransmission timer value, and so it
 *  mustn't be zero.
 *  2 seems like a reasonable minimum.
 */
ProtoHook
tp_input(m, faddr, laddr, cons_channel, dgout_routine, ce_bit)
	register	struct mbuf 	*m;
	struct sockaddr 			*faddr, *laddr; /* NSAP addresses */
	caddr_t						cons_channel;
	int 						(*dgout_routine)();
	int							ce_bit;

{
	register struct tp_pcb 	*tpcb;
	register struct tpdu 	*hdr;
	struct socket 			*so;
	struct tp_event 		e;
	int 					error;
	unsigned 				dutype;
	u_short 				dref, sref, acktime, subseq;
	u_char 					preferred_class, class_to_use, pdusize;
	u_char					opt, dusize, addlopt, version;
#ifdef TP_PERF_MEAS
	u_char					perf_meas;
#endif /* TP_PERF_MEAS */
	u_char					fsufxlen, lsufxlen;
	caddr_t					fsufxloc, lsufxloc;
	int						tpdu_len;
	u_int 					takes_data;
	u_int					fcc_present; 
	int						errlen;
	struct tp_conn_param 	tpp;
	int						tpcons_output();

again:
	hdr = mtod(m, struct tpdu *);
	tpcb = 0;
	error = errlen = tpdu_len = 0;
	takes_data = fcc_present = FALSE;
	acktime = 2; sref = subseq = 0;
	fsufxloc = lsufxloc = NULL;
	fsufxlen = lsufxlen =
		preferred_class = class_to_use = pdusize = addlopt = 0;
	dusize = TP_DFL_TPDUSIZE;
#ifdef TP_PERF_MEAS
	GET_CUR_TIME( &e.e_time ); perf_meas = 0;
#endif /* TP_PERF_MEAS */
	
	IFDEBUG(D_TPINPUT)
		printf("tp_input(0x%x, ... 0x%x)\n", m, cons_channel);
	ENDDEBUG


	/* 
	 * get the actual tpdu length - necessary for monitoring
	 * and for checksumming
	 * 
	 * Also, maybe measure the mbuf chain lengths and sizes.
	 */

	{ 	register struct mbuf *n=m;
#	ifdef ARGO_DEBUG
		int chain_length = 0;
#	endif ARGO_DEBUG

		for(;;) {
			tpdu_len += n->m_len;
			IFDEBUG(D_MBUF_MEAS)
				if( n->m_flags & M_EXT) {
					IncStat(ts_mb_cluster);
				} else {
					IncStat(ts_mb_small);
				}
				chain_length ++;
			ENDDEBUG
			if (n->m_next == MNULL ) {
				break;
			}
			n = n->m_next;
		}
		IFDEBUG(D_MBUF_MEAS)
			if(chain_length > 16)
				chain_length = 0; /* zero used for anything > 16 */
			tp_stat.ts_mb_len_distr[chain_length] ++;
		ENDDEBUG
	}
	IFTRACE(D_TPINPUT)
		tptraceTPCB(TPPTtpduin, hdr->tpdu_type, hdr, hdr->tpdu_li+1, tpdu_len, 
			0);
	ENDTRACE

	dref = ntohs((short)hdr->tpdu_dref);
	sref = ntohs((short)hdr->tpdu_sref);
	dutype = (int)hdr->tpdu_type;

	IFDEBUG(D_TPINPUT)
		printf("input: dutype 0x%x cons_channel 0x%x dref 0x%x\n", dutype,
			cons_channel, dref);
		printf("input: dref 0x%x sref 0x%x\n", dref, sref);
	ENDDEBUG
	IFTRACE(D_TPINPUT)
		tptrace(TPPTmisc, "channel dutype dref ", 
			cons_channel, dutype, dref, 0);
	ENDTRACE


#ifdef ARGO_DEBUG
	if( (dutype < TP_MIN_TPDUTYPE) || (dutype > TP_MAX_TPDUTYPE)) {
		printf("BAD dutype! 0x%x, channel 0x%x dref 0x%x\n",
			dutype, cons_channel, dref);
		dump_buf (m, sizeof( struct mbuf ));

		IncStat(ts_inv_dutype);
		goto discard;
	}
#endif /* ARGO_DEBUG */

	CHECK( (dutype < TP_MIN_TPDUTYPE || dutype > TP_MAX_TPDUTYPE),
		E_TP_INV_TPDU, ts_inv_dutype, respond, 
		2 );
		/* unfortunately we can't take the address of the tpdu_type field,
		 * since it's a bit field - so we just use the constant offset 2
		 */

	/* Now this isn't very neat but since you locate a pcb one way
	 * at the beginning of connection establishment, and by
	 * the dref for each tpdu after that, we have to treat CRs differently
	 */
	if ( dutype == CR_TPDU_type ) {
		u_char alt_classes = 0;

		preferred_class = 1 << hdr->tpdu_CRclass;
		opt = hdr->tpdu_CRoptions;

		WHILE_OPTIONS(P, hdr, 1 ) /* { */

			switch( vbptr(P)->tpv_code ) {

			case	TPP_tpdu_size: 		
				vb_getval(P, u_char, dusize);
				IFDEBUG(D_TPINPUT)
					printf("CR dusize 0x%x\n", dusize);
				ENDDEBUG
				/* COS tests: NBS IA (Dec. 1987) Sec. 4.5.2.1 */
				if (dusize < TP_MIN_TPDUSIZE || dusize > TP_MAX_TPDUSIZE)
						dusize = TP_DFL_TPDUSIZE;
				break;
			case	TPP_ptpdu_size:
				switch (vbptr(P)->tpv_len) {
				case 1: pdusize = vbval(P, u_char); break;
				case 2: pdusize = ntohs(vbval(P, u_short)); break;
				default: ;
				IFDEBUG(D_TPINPUT)
					printf("malformed prefered TPDU option\n");
				ENDDEBUG
				}
				break;
			case	TPP_addl_opt:
				vb_getval(P, u_char, addlopt);
				break;
			case	TPP_calling_sufx:
				/* could use vb_getval, but we want to save the loc & len
				 * for later use
				 */
				fsufxloc = (caddr_t) &vbptr(P)->tpv_val;
				fsufxlen = vbptr(P)->tpv_len;
				IFDEBUG(D_TPINPUT)
					printf("CR fsufx:");
					{ register int j;
						for(j=0; j<fsufxlen; j++ ) {
							printf(" 0x%x. ", *((caddr_t)(fsufxloc+j)) );
						}
						printf("\n");
					}
				ENDDEBUG
				break;
			case	TPP_called_sufx:
				/* could use vb_getval, but we want to save the loc & len
				 * for later use
				 */
				lsufxloc = (caddr_t) &vbptr(P)->tpv_val;
				lsufxlen = vbptr(P)->tpv_len;
				IFDEBUG(D_TPINPUT)
					printf("CR lsufx:");
					{ register int j;
						for(j=0; j<lsufxlen; j++ ) {
							printf(" 0x%x. ", *((u_char *)(lsufxloc+j)) );
						}
						printf("\n");
					}
				ENDDEBUG
				break;

#ifdef TP_PERF_MEAS
			case	TPP_perf_meas:
				vb_getval(P, u_char, perf_meas);
				break;
#endif /* TP_PERF_MEAS */

			case	TPP_vers:
				/* not in class 0; 1 octet; in CR_TPDU only */
				/* COS tests says if version wrong, use default version!?XXX */
				CHECK( (vbval(P, u_char) != TP_VERSION ), 
					E_TP_INV_PVAL, ts_inv_pval, setversion,
					(1 + (caddr_t)&vbptr(P)->tpv_val - (caddr_t)hdr) );
			setversion:
				version = vbval(P, u_char);
				break;
			case	TPP_acktime:
				vb_getval(P, u_short, acktime);
				acktime = ntohs(acktime);
				acktime = acktime/500; /* convert to slowtimo ticks */
				if((short)acktime <=0 )
					acktime = 2; /* don't allow a bad peer to screw us up */
				IFDEBUG(D_TPINPUT)
					printf("CR acktime 0x%x\n", acktime);
				ENDDEBUG
				break;

			case	TPP_alt_class:
				{
					u_char *aclass = 0;
					register int i;
					static u_char bad_alt_classes[5] =
						{ ~0, ~3, ~5, ~0xf, ~0x1f};

					aclass = 
						(u_char *) &(((struct tp_vbp *)P)->tpv_val);
					for (i = ((struct tp_vbp *)P)->tpv_len; i>0; i--) {
						alt_classes |= (1<<((*aclass++)>>4));
					}
					CHECK( (bad_alt_classes[hdr->tpdu_CRclass] & alt_classes),
						E_TP_INV_PVAL, ts_inv_aclass, respond,
						((caddr_t)aclass) - (caddr_t)hdr);
					IFDEBUG(D_TPINPUT)
						printf("alt_classes 0x%x\n", alt_classes);
					ENDDEBUG
				}
				break;

			case	TPP_security:
			case	TPP_residER:
			case	TPP_priority:
			case	TPP_transdelay:
			case	TPP_throughput: 
			case	TPP_addl_info: 
			case	TPP_subseq:
			default:
				IFDEBUG(D_TPINPUT)
					printf("param ignored CR_TPDU code= 0x%x\n",
						 vbptr(P)->tpv_code);
				ENDDEBUG
				IncStat(ts_param_ignored);
				break;

			case	TPP_checksum:		
				IFDEBUG(D_TPINPUT)
					printf("CR before cksum\n");
				ENDDEBUG

				CHECK( iso_check_csum(m, tpdu_len), 
					E_TP_INV_PVAL, ts_bad_csum, discard, 0)

				IFDEBUG(D_TPINPUT)
					printf("CR before cksum\n");
				ENDDEBUG
				break;
			}

		/* } */ END_WHILE_OPTIONS(P)

		if (lsufxlen == 0) {
			/* can't look for a tpcb w/o any called sufx */
			error =  E_TP_LENGTH_INVAL;
			IncStat(ts_inv_sufx);
			goto respond;
		} else {
			register struct tp_pcb *t;
			/*
			 * The intention here is to trap all CR requests
			 * to a given nsap, for constructing transport
			 * service bridges at user level; so these
			 * intercepts should precede the normal listens.
			 * Phrasing the logic in this way also allows for
			 * mop-up listeners, which we don't currently implement.
			 * We also wish to have a single socket be able to
			 * listen over any network service provider,
			 * (cons or clns or ip).
			 */
			for (t = tp_listeners; t ; t = t->tp_nextlisten)
				if ((t->tp_lsuffixlen == 0 ||
					 (lsufxlen == t->tp_lsuffixlen &&
					  bcmp(lsufxloc, t->tp_lsuffix, lsufxlen) == 0)) &&
					((t->tp_flags & TPF_GENERAL_ADDR) ||
					 (laddr->sa_family == t->tp_domain &&
					  (*t->tp_nlproto->nlp_cmpnetaddr)
								(t->tp_npcb, laddr, TP_LOCAL))))
					break;

			CHECK(t == 0, E_TP_NO_SESSION, ts_inv_sufx, respond,
				(1 + 2 + (caddr_t)&hdr->_tpduf - (caddr_t)hdr))
				/* _tpduf is the fixed part; add 2 to get the dref bits of 
				 * the fixed part (can't take the address of a bit field) 
				 */
			IFDEBUG(D_TPINPUT)
				printf("checking if dup CR\n");
			ENDDEBUG
			tpcb = t;
			for (t = tpcb->tp_next; t != tpcb; t = t->tp_next) {
				if (sref != t->tp_fref)
					continue;
				if ((*tpcb->tp_nlproto->nlp_cmpnetaddr)(
						t->tp_npcb, faddr, TP_FOREIGN)) {
					IFDEBUG(D_TPINPUT)
						printf("duplicate CR discarded\n");
					ENDDEBUG
					goto discard;
				}
			}
			IFTRACE(D_TPINPUT)
				tptrace(TPPTmisc, "tp_input: tpcb *lsufxloc tpstate", 
					tpcb, *lsufxloc, tpcb->tp_state, 0);
			ENDTRACE
		}

		/* 
		 * WE HAVE A TPCB 
		 * already know that the classes in the CR match at least
		 * one class implemented, but we don't know yet if they
		 * include any classes permitted by this server.
		 */

		IFDEBUG(D_TPINPUT)
			printf("HAVE A TPCB 1: 0x%x\n", tpcb);
		ENDDEBUG
		IFDEBUG(D_CONN)
			printf(
"CR: bef CHKS: flags 0x%x class_to_use 0x%x alt 0x%x opt 0x%x tp_class 0x%x\n", 
				tpcb->tp_flags, class_to_use, alt_classes, opt, tpcb->tp_class);
		ENDDEBUG
		/* tpcb->tp_class doesn't include any classes not implemented  */
		class_to_use = (preferred_class & tpcb->tp_class);
		if( (class_to_use = preferred_class & tpcb->tp_class) == 0 )
			class_to_use = alt_classes & tpcb->tp_class;

		class_to_use = 1 << tp_mask_to_num(class_to_use);

		{
			tpp = tpcb->_tp_param;
			tpp.p_class = class_to_use;
			tpp.p_tpdusize = dusize;
			tpp.p_ptpdusize = pdusize;
			tpp.p_xtd_format = (opt & TPO_XTD_FMT) == TPO_XTD_FMT;
			tpp.p_xpd_service = (addlopt & TPAO_USE_TXPD) == TPAO_USE_TXPD;
			tpp.p_use_checksum = (tpp.p_class == TP_CLASS_0)?0:
				(addlopt & TPAO_NO_CSUM) == 0;
			tpp.p_version = version;
#ifdef notdef
			tpp.p_use_efc = (opt & TPO_USE_EFC) == TPO_USE_EFC;
			tpp.p_use_nxpd = (addlopt & TPAO_USE_NXPD) == TPAO_USE_NXPD;
			tpp.p_use_rcc = (addlopt & TPAO_USE_RCC) == TPAO_USE_RCC;
#endif /* notdef */

		CHECK(
			tp_consistency(tpcb, 0 /* not force or strict */, &tpp) != 0, 
			E_TP_NEGOT_FAILED, ts_negotfailed, clear_parent_tcb,
			(1 + 2 + (caddr_t)&hdr->_tpdufr.CRCC - (caddr_t)hdr) 
				/* ^ more or less the location of class */
			)
		}
		IFTRACE(D_CONN)
			tptrace(TPPTmisc, 
				"after 1 consist class_to_use class, out, tpconsout",
				class_to_use, 
				tpcb->tp_class, dgout_routine, tpcons_output
				);
		ENDTRACE
		CHECK(
			((class_to_use == TP_CLASS_0)&&(dgout_routine != tpcons_output)),
			E_TP_NEGOT_FAILED, ts_negotfailed, clear_parent_tcb,
			(1 + 2 + (caddr_t)&hdr->_tpdufr.CRCC - (caddr_t)hdr) 
				/* ^ more or less the location of class */
			)
		IFDEBUG(D_CONN)
			printf("CR: after CRCCCHECKS: tpcb 0x%x, flags 0x%x\n", 
				tpcb, tpcb->tp_flags);
		ENDDEBUG
		takes_data = TRUE;
		e.ATTR(CR_TPDU).e_cdt  =  hdr->tpdu_CRcdt;
		e.ev_number = CR_TPDU;

		so = tpcb->tp_sock;
		if (so->so_options & SO_ACCEPTCONN) {
			struct tp_pcb *parent_tpcb = tpcb;
			/* 
			 * Create a socket, tpcb, ll pcb, etc. 
			 * for this newborn connection, and fill in all the values. 
			 */
			IFDEBUG(D_CONN)
				printf("abt to call tp_newsocket(0x%x, 0x%x, 0x%x, 0x%x)\n",
					so, laddr, faddr, cons_channel);
			ENDDEBUG
			if( (so =