llc_subr.c

早期freebsd实现

			action = 0;
		} else if (pollfinal == 0 || 
			   (cmdrsp == LLC_RSP && pollfinal == 1 && p == 1)) {
			LLC_UPDATE_NR_RECEIVED(linkp, nr);
			LLC_UPDATE_P_FLAG(linkp, cmdrsp, pollfinal);
			if (cmdrsp == LLC_RSP && pollfinal == 1) {
				LLC_CLEAR_REMOTE_BUSY(linkp, action);
			} else action = 0;
		}
		break;
	}
	case LLCFT_INFO + LLC_CMD:
	case LLCFT_INFO + LLC_RSP: {
		register int p = LLC_GETFLAG(linkp, P);
		register int nr = LLCGBITS(frame->llc_control_ext, s_nr);
		
		if (cmdrsp == LLC_CMD && pollfinal == 1) {
			LLC_INC(linkp->llcl_vr);
			LLC_SENDACKNOWLEDGE(linkp, LLC_RSP, 1);
			LLC_UPDATE_NR_RECEIVED(linkp, nr);
			LLC_STOP_REJ_TIMER(linkp);
			LLC_NEWSTATE(linkp, NORMAL);
			action = LLC_DATA_INDICATION;
		} else if ((cmdrsp = LLC_RSP && pollfinal == p) ||
			   (cmdrsp == LLC_CMD && pollfinal == 0 && p == 0)) {
			LLC_INC(linkp->llcl_vr);
			LLC_SENDACKNOWLEDGE(linkp, LLC_CMD, 1);
			LLC_START_P_TIMER(linkp);
			LLC_UPDATE_NR_RECEIVED(linkp, nr);
			if (cmdrsp == LLC_RSP && pollfinal == 1)
				LLC_CLEAR_REMOTE_BUSY(linkp, action);
			LLC_STOP_REJ_TIMER(linkp);
			LLC_NEWSTATE(linkp, NORMAL);
			action = LLC_DATA_INDICATION;
		} else if (pollfinal == 0 && p == 1) {
			LLC_INC(linkp->llcl_vr);
			LLC_SENDACKNOWLEDGE(linkp, LLC_CMD, 0);
			LLC_STOP_REJ_TIMER(linkp);
			LLC_NEWSTATE(linkp, NORMAL);
			action = LLC_DATA_INDICATION;
		}
		break;
	}
	case LLCFT_RR + LLC_CMD:
	case LLCFT_RR + LLC_RSP: {
		register int p = LLC_GETFLAG(linkp, P);
		register int nr = LLCGBITS(frame->llc_control_ext, s_nr);

		if (cmdrsp == LLC_CMD && pollfinal == 1) {
			LLC_SENDACKNOWLEDGE(linkp, LLC_RSP, 1);
			LLC_UPDATE_NR_RECEIVED(linkp, nr);
			LLC_CLEAR_REMOTE_BUSY(linkp, action);
		} else if (pollfinal == 0 || 
			   (cmdrsp == LLC_RSP && pollfinal == 1 && p == 1)) {
			LLC_UPDATE_P_FLAG(linkp, cmdrsp, pollfinal);
			LLC_UPDATE_NR_RECEIVED(linkp, nr);
			LLC_CLEAR_REMOTE_BUSY(linkp, action);
		}
		break;
	}
	case LLCFT_RNR + LLC_CMD:
	case LLCFT_RNR + LLC_RSP: {
		register int p = LLC_GETFLAG(linkp, P);
		register int nr = LLCGBITS(frame->llc_control_ext, s_nr);
		
		if (cmdrsp == LLC_CMD && pollfinal == 1) {
			llc_send(linkp, LLCFT_RR, LLC_RSP, 1);
			LLC_UPDATE_NR_RECEIVED(linkp, nr);
			LLC_SET_REMOTE_BUSY(linkp, action);
		} else if (pollfinal == 0 ||
			   (cmdrsp == LLC_RSP && pollfinal == 1 && p == 1)) {
			LLC_UPDATE_P_FLAG(linkp, cmdrsp, pollfinal);
			LLC_UPDATE_NR_RECEIVED(linkp, nr);
			action = 0;
		}
		break;
	}
	case LLCFT_REJ + LLC_CMD:
	case LLCFT_REJ + LLC_RSP: {
		register int p = LLC_GETFLAG(linkp, P);
		register int nr = LLCGBITS(frame->llc_control_ext, s_nr);

		if (cmdrsp == LLC_CMD && pollfinal == 1) {
			linkp->llcl_vs = nr;
			LLC_UPDATE_NR_RECEIVED(linkp, nr);
			llc_resend(linkp, LLC_RSP, 1);
			LLC_CLEAR_REMOTE_BUSY(linkp, action);
		} else if ((cmdrsp == LLC_CMD && pollfinal == 0 && p == 0) ||
			   (cmdrsp == LLC_RSP && pollfinal == p)) {
			linkp->llcl_vs = nr;
			LLC_UPDATE_NR_RECEIVED(linkp, nr);
			LLC_UPDATE_P_FLAG(linkp, cmdrsp, pollfinal);
			llc_resend(linkp, LLC_CMD, 0);
			LLC_CLEAR_REMOTE_BUSY(linkp, action);
		} else if (pollfinal == 0 && p == 1) {
			linkp->llcl_vs = nr;
			LLC_UPDATE_NR_RECEIVED(linkp, nr);
			llc_resend(linkp, LLC_CMD, 0);
			LLC_CLEAR_REMOTE_BUSY(linkp, action);
		}
		break;
	}
	case NL_INITIATE_PF_CYCLE:
		if (LLC_GETFLAG(linkp, P) == 0) {
			llc_send(linkp, LLCFT_RR, LLC_CMD, 1);
			LLC_START_P_TIMER(linkp);
			action = 0;
		}
		break;
	case LLC_REJ_TIMER_EXPIRED:
		if (LLC_GETFLAG(linkp, P) == 0 && linkp->llcl_retry < llc_n2) {
			llc_send(linkp, LLCFT_REJ, LLC_CMD, 1);
			LLC_START_P_TIMER(linkp);
			LLC_START_REJ_TIMER(linkp);
			linkp->llcl_retry++;
			action = 0;
		}
	case LLC_P_TIMER_EXPIRED:
		if (linkp->llcl_retry < llc_n2) {
			llc_send(linkp, LLCFT_RR, LLC_CMD, 1);
			LLC_START_P_TIMER(linkp);
			LLC_START_REJ_TIMER(linkp);
			linkp->llcl_retry++;
			LLC_NEWSTATE(linkp, AWAIT_REJECT);
			action = 0;
		}
		break;
	case LLC_ACK_TIMER_EXPIRED:
	case LLC_BUSY_TIMER_EXPIRED:
		if (LLC_GETFLAG(linkp, P) == 0 && linkp->llcl_retry < llc_n2) {
			llc_send(linkp, LLCFT_RR, LLC_CMD, 1);
			LLC_START_P_TIMER(linkp);
			LLC_START_REJ_TIMER(linkp);
			linkp->llcl_retry++;
			/* 
			 * I cannot locate the description of RESET_V(S)
			 * in ISO 8802-2, table 7-1, state REJECT, last event,
			 * and  assume they meant to set V(S) to 0 ...
			 */
			linkp->llcl_vs = 0; /* XXX */
			LLC_NEWSTATE(linkp, AWAIT_REJECT);
			action = 0;
		}

		break;
	}
	if (action == LLC_PASSITON)
		action = llc_state_NBRAcore(linkp, frame, frame_kind, 
					    cmdrsp, pollfinal);

	return action;
}

/*
 * AWAIT --- A data link connection exists between the local LLC service access
 *           point and the remote LLC service access point. The local LLC is
 *           performing a timer recovery operation and has sent a command PDU
 *           with the P bit set to ``1'', and is awaiting an acknowledgement
 *           from the remote LLC. I PDUs may be received but not sent.
 *           Supervisory PDUs may be both sent and received.
 */
int
llc_state_AWAIT(struct llc_linkcb *linkp, struct llc *frame, int frame_kind,
		int cmdrsp, int pollfinal)
{
	int action = LLC_PASSITON;

	switch(frame_kind + cmdrsp) {
	case LLC_LOCAL_BUSY_DETECTED:
		llc_send(linkp, LLCFT_RNR, LLC_CMD, 0);
		LLC_SETFLAG(linkp, DATA, 0);
		LLC_NEWSTATE(linkp, AWAIT_BUSY);
		action = 0;
		break;
	case LLC_INVALID_NS + LLC_CMD:
	case LLC_INVALID_NS + LLC_RSP: {
		register int p = LLC_GETFLAG(linkp, P);
		register int nr = LLCGBITS(frame->llc_control_ext, s_nr);
		
		if (cmdrsp == LLC_CMD && pollfinal == 1) {
			llc_send(linkp, LLCFT_REJ, LLC_RSP, 1);
			LLC_UPDATE_NR_RECEIVED(linkp, nr);
			LLC_START_REJ_TIMER(linkp);
			LLC_NEWSTATE(linkp, AWAIT_REJECT);
			action = 0;
		} else if (cmdrsp == LLC_RSP && pollfinal == 1) {
			llc_send(linkp, LLCFT_REJ, LLC_CMD, 0);
			LLC_UPDATE_NR_RECEIVED(linkp, nr);
			linkp->llcl_vs = nr;
			LLC_STOP_P_TIMER(linkp);
			llc_resend(linkp, LLC_CMD, 0);
			LLC_START_REJ_TIMER(linkp);
			LLC_CLEAR_REMOTE_BUSY(linkp, action);
			LLC_NEWSTATE(linkp, REJECT);
		} else if (pollfinal == 0) {
			llc_send(linkp, LLCFT_REJ, LLC_CMD, 0);
			LLC_UPDATE_NR_RECEIVED(linkp, nr);
			LLC_START_REJ_TIMER(linkp);
			LLC_NEWSTATE(linkp, AWAIT_REJECT);
			action = 0;
		}
		break;
	}
	case LLCFT_INFO + LLC_RSP:
	case LLCFT_INFO + LLC_CMD: {
		register int p = LLC_GETFLAG(linkp, P);
		register int nr = LLCGBITS(frame->llc_control_ext, s_nr);
		
		LLC_INC(linkp->llcl_vr);
		if (cmdrsp == LLC_CMD && pollfinal == 1) {
			llc_send(linkp, LLCFT_RR, LLC_RSP, 1);
			LLC_UPDATE_NR_RECEIVED(linkp, nr);
			action = LLC_DATA_INDICATION;
		} else if (cmdrsp == LLC_RSP && pollfinal == 1) {
			LLC_UPDATE_NR_RECEIVED(linkp, nr);
			linkp->llcl_vs = nr;
			llc_resend(linkp, LLC_CMD, 1);
			LLC_START_P_TIMER(linkp);
			LLC_CLEAR_REMOTE_BUSY(linkp, action);
			LLC_NEWSTATE(linkp, NORMAL);
			action = LLC_DATA_INDICATION;
		} else if (pollfinal == 0) {
			llc_send(linkp, LLCFT_RR, LLC_CMD, 0);
			LLC_UPDATE_NR_RECEIVED(linkp, nr);
			action = LLC_DATA_INDICATION;
		}
		break;
	}
	case LLCFT_RR + LLC_CMD:
	case LLCFT_RR + LLC_RSP:
	case LLCFT_REJ + LLC_CMD:
	case LLCFT_REJ + LLC_RSP: {
		register int p = LLC_GETFLAG(linkp, P);
		register int nr = LLCGBITS(frame->llc_control_ext, s_nr);
		
		if (cmdrsp == LLC_CMD && pollfinal == 1) {
			llc_send(linkp, LLCFT_RR, LLC_RSP, 1);
			LLC_UPDATE_NR_RECEIVED(linkp, nr);
			LLC_CLEAR_REMOTE_BUSY(linkp, action);
		} else if (cmdrsp == LLC_RSP && pollfinal == 1) {
			LLC_UPDATE_NR_RECEIVED(linkp, nr);
			linkp->llcl_vs = nr;
			LLC_STOP_P_TIMER(linkp);
			llc_resend(linkp, LLC_CMD, 0);
			LLC_CLEAR_REMOTE_BUSY(linkp, action);
			LLC_NEWSTATE(linkp, NORMAL);
		} else if (pollfinal == 0) {
			LLC_UPDATE_NR_RECEIVED(linkp, nr);
			LLC_CLEAR_REMOTE_BUSY(linkp, action);
		}	
		break;
	}
	case LLCFT_RNR + LLC_CMD:
	case LLCFT_RNR + LLC_RSP: {
		register int p = LLC_GETFLAG(linkp, P);
		register int nr = LLCGBITS(frame->llc_control_ext, s_nr);

		if (pollfinal == 1 && cmdrsp == LLC_CMD) {
			llc_send(linkp, LLCFT_RR, LLC_RSP, 1);
			LLC_UPDATE_NR_RECEIVED(linkp, nr);
			LLC_SET_REMOTE_BUSY(linkp, action);
		} else if (pollfinal == 1 && cmdrsp == LLC_RSP) {
			LLC_UPDATE_NR_RECEIVED(linkp, nr);
			linkp->llcl_vs = nr;
			LLC_STOP_P_TIMER(linkp);
			LLC_SET_REMOTE_BUSY(linkp, action);
			LLC_NEWSTATE(linkp, NORMAL);
		} else if (pollfinal == 0) {
			LLC_UPDATE_NR_RECEIVED(linkp, nr);
			LLC_SET_REMOTE_BUSY(linkp, action);
		}
		break;
	}
	case LLC_P_TIMER_EXPIRED:
		if (linkp->llcl_retry < llc_n2) {
			llc_send(linkp, LLCFT_RR, LLC_CMD, 1);
			LLC_START_P_TIMER(linkp);
			linkp->llcl_retry++;
			action = 0;
		}
		break;
	}
	if (action == LLC_PASSITON)
		action = llc_state_NBRAcore(linkp, frame, frame_kind, 
					    cmdrsp, pollfinal);

	return action;
}

/*
 * AWAIT_BUSY --- A data link connection exists between the local LLC service
 *                access point and the remote LLC service access point. The
 *                local LLC is performing a timer recovery operation and has
 *                sent a command PDU with the P bit set to ``1'', and is
 *                awaiting an acknowledgement from the remote LLC. I PDUs may
 *                not be sent. Local conditions make it likely that the
 *                information feld of receoved I PDUs will be ignored.
 *                Supervisory PDUs may be both sent and received.
 */
int
llc_state_AWAIT_BUSY(struct llc_linkcb *linkp, struct llc *frame, int frame_kind,
		     int cmdrsp, int pollfinal)
{
	int action = LLC_PASSITON;

	switch(frame_kind + cmdrsp) {
	case LLC_LOCAL_BUSY_CLEARED:
		switch (LLC_GETFLAG(linkp, DATA)) {
		case 1:
			llc_send(linkp, LLCFT_REJ, LLC_CMD, 0);
			LLC_START_REJ_TIMER(linkp);
			LLC_NEWSTATE(linkp, AWAIT_REJECT);
			action = 0;
			break;
		case 0:
			llc_send(linkp, LLCFT_RR, LLC_CMD, 0);
			LLC_NEWSTATE(linkp, AWAIT);
			action = 0;
			break;
		case 2:
			llc_send(linkp, LLCFT_RR, LLC_CMD, 0);
			LLC_NEWSTATE(linkp, AWAIT_REJECT);
			action = 0;
			break;
		}
		break;
	case LLC_INVALID_NS + LLC_CMD:
	case LLC_INVALID_NS + LLC_RSP: {
		register int p = LLC_GETFLAG(linkp, P);
		register int nr = LLCGBITS(frame->llc_control_ext, s_nr);

		if (cmdrsp == LLC_CMD && pollfinal == 1) {
			llc_send(linkp, LLCFT_RNR, LLC_RSP, 1);
			LLC_UPDATE_NR_RECEIVED(linkp, nr);
			LLC_SETFLAG(linkp, DATA, 1);
			action = 0;
		} else if (cmdrsp == LLC_RSP && pollfinal == 1) {
			/* optionally */
			llc_send(linkp, LLCFT_RNR, LLC_CMD, 0);
			LLC_UPDATE_NR_RECEIVED(linkp, nr);
			linkp->llcl_vs = nr;
			LLC_STOP_P_TIMER(linkp);
			LLC_SETFLAG(linkp, DATA, 1);
			LLC_CLEAR_REMOTE_BUSY(linkp, action);
			llc_resend(linkp, LLC_CMD, 0);
			LLC_NEWSTATE(linkp, BUSY);
		} else if (pollfinal == 0) {
			/* optionally */
			llc_send(linkp, LLCFT_RNR, LLC_CMD, 0);
			LLC_UPDATE_NR_RECEIVED(linkp, nr);
			LLC_SETFLAG(linkp, DATA, 1);
			action = 0;
		}
	}
	case LLCFT_INFO + LLC_CMD:
	case LLCFT_INFO + LLC_RSP: {
		register int p = LLC_GETFLAG(linkp, P);
		register int nr = LLCGBITS(frame->llc_control_ext, s_nr);
		
		if (cmdrsp == LLC_CMD && pollfinal == 1) {
			llc_send(linkp, LLCFT_RNR, LLC_RSP, 1);
			LLC_INC(linkp->llcl_vr);
			LLC_UPDATE_NR_RECEIVED(linkp, nr);
			LLC_SETFLAG(linkp, DATA, 0);
			action = LLC_DATA_INDICATION;
		} else if (cmdrsp == LLC_RSP && pollfinal == 1) {
			llc_send(linkp, LLCFT_RNR, LLC_CMD, 1);
			LLC_INC(linkp->llcl_vr);
			LLC_START_P_TIMER(linkp);
			LLC_UPDATE_NR_RECEIVED(linkp, nr);
			linkp->llcl_vs = nr;
			LLC_SETFLAG(linkp, DATA, 0);
			LLC_CLEAR_REMOTE_BUSY(linkp, action);
			llc_resend(linkp, LLC_CMD, 0);
			LLC_NEWSTATE(linkp, BUSY);
			action = LLC_DATA_INDICATION;
		} else if (pollfinal == 0) {
			llc_send(linkp, LLCFT_RNR, LLC_CMD, 0);
			LLC_INC(linkp->llcl_vr);
			LLC_UPDATE_NR_RECEIVED(linkp, nr);
			LLC_SETFLAG(linkp, DATA, 0);
			action = LLC_DATA_INDICATION;
		}
		break;
	}
	case LLCFT_RR + LLC_CMD:
	case LLCFT_REJ + LLC_CMD:
	case LLCFT_RR + LLC_RSP:
	case LLCFT_REJ + LLC_RSP: {
		register int p = LLC_GETFLAG(linkp, P);
		register int nr = LLCGBITS(frame->llc_control_ext, s_nr);
		
		if (cmdrsp == LLC_CMD && pollfinal == 1) {
			llc_send(linkp, LLCFT_RNR, LLC_RSP, 1);
			LLC_UPDATE_NR_RECEIVED(linkp, nr);
			LLC_CLEAR_REMOTE_BUSY(linkp, action);
		} else if (cmdrsp == LLC_RSP && pollfinal == 1) {
			LLC_UPDATE_NR_RECEIVED(linkp, nr);
			linkp->llcl_vs = nr;
			LLC_STOP_P_TIMER(linkp);
			llc_resend(linkp, LLC_CMD, 0);
			LLC_CLEAR_REMOTE_BUSY(linkp, action);
			LLC_NEWSTATE(linkp, BUSY);
		} else if (pollfinal == 0) {
			LLC_UPDATE_NR_RECEIVED(linkp, nr);
			linkp->llcl_vs = nr;
			LLC_STOP_P_TIMER(linkp);
			llc_resend(linkp, LLC_CMD, 0);
			LLC_CLEAR_REMOTE_BUSY(linkp, action);
		}
		break;
	}
	case LLCFT_RNR + LLC_CMD:
	case LLCFT_RNR + LLC_RSP: {
		register int p = LLC_GETFLAG(linkp, P);
		register int nr = LLCGBITS(frame->llc_control_ext, s_nr);
		
		if (cmdrsp == LLC_CMD && pollfinal == 1) {
			llc_send(linkp, LLCFT_RNR, LLC_RSP, 1);
			LLC_UPDATE_NR_RECEIVED(linkp, nr);
			LLC_SET_REMOTE_BUSY(linkp, action);
		} else if (cmdrsp == LLC_RSP && pollfinal == 1) {
			LLC_UPDATE_NR_RECEIVED(linkp, nr);
			linkp->llcl_vs = nr;
			LLC_STOP_P_TIMER(linkp);
			LLC_SET_REMOTE_BUSY(linkp, action);
			LLC_NEWSTATE(linkp, BUSY);
		} else if (pollfinal == 0) {
			LLC_UPDATE_NR_RECEIVED(linkp, nr);
			LLC_SET_REMOTE_BUSY(linkp, action);
		}
		break;
	}
	case LLC_P_TIMER_EXPIRED:
		if (linkp->llcl_retry < llc_n2) {
			llc_send(linkp, LLCFT_RNR, LLC_CMD, 1);
			LLC_START_P_TIMER(linkp);
			linkp->llcl_retry++;
			action = 0;
		}
		break;
	}
	if (action == LLC_PASSITON)
		action = llc_state_NBRAcore(linkp, frame, frame_kind, 
					    cmdrsp, pollfinal);

	return action;
}

/*