lapb_in.c

ARM 嵌入式 系统 设计与实例开发 实验教材 二源码

			printk(KERN_DEBUG "lapb: (%p) S3 RX SABME(%d)\n", lapb->token, frame->pf);
#endif
			if (lapb->mode & LAPB_EXTENDED) {
#if LAPB_DEBUG > 1
				printk(KERN_DEBUG "lapb: (%p) S3 TX UA(%d)\n", lapb->token, frame->pf);
#endif
				lapb_send_control(lapb, LAPB_UA, frame->pf, LAPB_RESPONSE);
				lapb_stop_t1timer(lapb);
				lapb_stop_t2timer(lapb);
				lapb->condition = 0x00;
				lapb->n2count   = 0;
				lapb->vs        = 0;
				lapb->vr        = 0;
				lapb->va        = 0;
				lapb_requeue_frames(lapb);
			} else {
#if LAPB_DEBUG > 1
				printk(KERN_DEBUG "lapb: (%p) S3 TX DM(%d)\n", lapb->token, frame->pf);
#endif
				lapb_send_control(lapb, LAPB_DM, frame->pf, LAPB_RESPONSE);
			}
			break;

		case LAPB_DISC:
#if LAPB_DEBUG > 1
			printk(KERN_DEBUG "lapb: (%p) S3 RX DISC(%d)\n", lapb->token, frame->pf);
#endif
#if LAPB_DEBUG > 0
			printk(KERN_DEBUG "lapb: (%p) S3 -> S0\n", lapb->token);
#endif
			lapb_clear_queues(lapb);
			lapb_send_control(lapb, LAPB_UA, frame->pf, LAPB_RESPONSE);
			lapb_start_t1timer(lapb);
			lapb_stop_t2timer(lapb);
			lapb->state = LAPB_STATE_0;
			lapb_disconnect_indication(lapb, LAPB_OK);
			break;

		case LAPB_DM:
#if LAPB_DEBUG > 1
			printk(KERN_DEBUG "lapb: (%p) S3 RX DM(%d)\n", lapb->token, frame->pf);
#endif
#if LAPB_DEBUG > 0
			printk(KERN_DEBUG "lapb: (%p) S3 -> S0\n", lapb->token);
#endif
			lapb_clear_queues(lapb);
			lapb->state = LAPB_STATE_0;
			lapb_start_t1timer(lapb);
			lapb_stop_t2timer(lapb);
			lapb_disconnect_indication(lapb, LAPB_NOTCONNECTED);
			break;

		case LAPB_RNR:
#if LAPB_DEBUG > 1
			printk(KERN_DEBUG "lapb: (%p) S3 RX RNR(%d) R%d\n", lapb->token, frame->pf, frame->nr);
#endif
			lapb->condition |= LAPB_PEER_RX_BUSY_CONDITION;
			lapb_check_need_response(lapb, frame->cr, frame->pf);
			if (lapb_validate_nr(lapb, frame->nr)) {
				lapb_check_iframes_acked(lapb, frame->nr);
			} else {
				lapb->frmr_data = *frame;
				lapb->frmr_type = LAPB_FRMR_Z;
				lapb_transmit_frmr(lapb);
#if LAPB_DEBUG > 0
				printk(KERN_DEBUG "lapb: (%p) S3 -> S4\n", lapb->token);
#endif
				lapb_start_t1timer(lapb);
				lapb_stop_t2timer(lapb);
				lapb->state   = LAPB_STATE_4;
				lapb->n2count = 0;
			}
			break;

		case LAPB_RR:
#if LAPB_DEBUG > 1
			printk(KERN_DEBUG "lapb: (%p) S3 RX RR(%d) R%d\n", lapb->token, frame->pf, frame->nr);
#endif
			lapb->condition &= ~LAPB_PEER_RX_BUSY_CONDITION;
			lapb_check_need_response(lapb, frame->cr, frame->pf);
			if (lapb_validate_nr(lapb, frame->nr)) {
				lapb_check_iframes_acked(lapb, frame->nr);
			} else {
				lapb->frmr_data = *frame;
				lapb->frmr_type = LAPB_FRMR_Z;
				lapb_transmit_frmr(lapb);
#if LAPB_DEBUG > 0
				printk(KERN_DEBUG "lapb: (%p) S3 -> S4\n", lapb->token);
#endif
				lapb_start_t1timer(lapb);
				lapb_stop_t2timer(lapb);
				lapb->state   = LAPB_STATE_4;
				lapb->n2count = 0;
			}
			break;

		case LAPB_REJ:
#if LAPB_DEBUG > 1
			printk(KERN_DEBUG "lapb: (%p) S3 RX REJ(%d) R%d\n", lapb->token, frame->pf, frame->nr);
#endif
			lapb->condition &= ~LAPB_PEER_RX_BUSY_CONDITION;
			lapb_check_need_response(lapb, frame->cr, frame->pf);
			if (lapb_validate_nr(lapb, frame->nr)) {
				lapb_frames_acked(lapb, frame->nr);
				lapb_stop_t1timer(lapb);
				lapb->n2count = 0;
				lapb_requeue_frames(lapb);
			} else {
				lapb->frmr_data = *frame;
				lapb->frmr_type = LAPB_FRMR_Z;
				lapb_transmit_frmr(lapb);
#if LAPB_DEBUG > 0
				printk(KERN_DEBUG "lapb: (%p) S3 -> S4\n", lapb->token);
#endif
				lapb_start_t1timer(lapb);
				lapb_stop_t2timer(lapb);
				lapb->state   = LAPB_STATE_4;
				lapb->n2count = 0;
			}
			break;

		case LAPB_I:
#if LAPB_DEBUG > 1
			printk(KERN_DEBUG "lapb: (%p) S3 RX I(%d) S%d R%d\n", lapb->token, frame->pf, frame->ns, frame->nr);
#endif
			if (!lapb_validate_nr(lapb, frame->nr)) {
				lapb->frmr_data = *frame;
				lapb->frmr_type = LAPB_FRMR_Z;
				lapb_transmit_frmr(lapb);
#if LAPB_DEBUG > 0
				printk(KERN_DEBUG "lapb: (%p) S3 -> S4\n", lapb->token);
#endif
				lapb_start_t1timer(lapb);
				lapb_stop_t2timer(lapb);
				lapb->state   = LAPB_STATE_4;
				lapb->n2count = 0;
				break;
			}
			if (lapb->condition & LAPB_PEER_RX_BUSY_CONDITION) {
				lapb_frames_acked(lapb, frame->nr);
			} else {
				lapb_check_iframes_acked(lapb, frame->nr);
			}
			if (frame->ns == lapb->vr) {
				int cn;
				cn = lapb_data_indication(lapb, skb);
				queued = 1;
				/*
				 * If upper layer has dropped the frame, we
				 * basically ignore any further protocol
				 * processing. This will cause the peer
				 * to re-transmit the frame later like
				 * a frame lost on the wire.
				 */
				if(cn == NET_RX_DROP){
					printk(KERN_DEBUG "LAPB: rx congestion\n");
					break;
				}
				lapb->vr = (lapb->vr + 1) % modulus;
				lapb->condition &= ~LAPB_REJECT_CONDITION;
				if (frame->pf) {
					lapb_enquiry_response(lapb);
				} else {
					if (!(lapb->condition & LAPB_ACK_PENDING_CONDITION)) {
						lapb->condition |= LAPB_ACK_PENDING_CONDITION;
						lapb_start_t2timer(lapb);
					}
				}
			} else {
				if (lapb->condition & LAPB_REJECT_CONDITION) {
					if (frame->pf)
						lapb_enquiry_response(lapb);
				} else {
#if LAPB_DEBUG > 1
					printk(KERN_DEBUG "lapb: (%p) S3 TX REJ(%d) R%d\n", lapb->token, frame->pf, lapb->vr);
#endif
					lapb->condition |= LAPB_REJECT_CONDITION;
					lapb_send_control(lapb, LAPB_REJ, frame->pf, LAPB_RESPONSE);
					lapb->condition &= ~LAPB_ACK_PENDING_CONDITION;
				}
			}
			break;

		case LAPB_FRMR:
#if LAPB_DEBUG > 1
			printk(KERN_DEBUG "lapb: (%p) S3 RX FRMR(%d) %02X %02X %02X %02X %02X\n", lapb->token, frame->pf, skb->data[0], skb->data[1], skb->data[2], skb->data[3], skb->data[4]);
#endif
			lapb_establish_data_link(lapb);
#if LAPB_DEBUG > 0
			printk(KERN_DEBUG "lapb: (%p) S3 -> S1\n", lapb->token);
#endif
			lapb_requeue_frames(lapb);
			lapb->state = LAPB_STATE_1;
			break;

		case LAPB_ILLEGAL:
#if LAPB_DEBUG > 1
			printk(KERN_DEBUG "lapb: (%p) S3 RX ILLEGAL(%d)\n", lapb->token, frame->pf);
#endif
			lapb->frmr_data = *frame;
			lapb->frmr_type = LAPB_FRMR_W;
			lapb_transmit_frmr(lapb);
#if LAPB_DEBUG > 0
			printk(KERN_DEBUG "lapb: (%p) S3 -> S4\n", lapb->token);
#endif
			lapb_start_t1timer(lapb);
			lapb_stop_t2timer(lapb);
			lapb->state   = LAPB_STATE_4;
			lapb->n2count = 0;
			break;

		default:
			break;
	}

	if (!queued)
		kfree_skb(skb);
}

/*
 *	State machine for state 4, Frame Reject State.
 *	The handling of the timer(s) is in file lapb_timer.c.
 */
static void lapb_state4_machine(lapb_cb *lapb, struct sk_buff *skb, struct lapb_frame *frame)
{
	switch (frame->type) {
		case LAPB_SABM:
#if LAPB_DEBUG > 1
			printk(KERN_DEBUG "lapb: (%p) S4 RX SABM(%d)\n", lapb->token, frame->pf);
#endif
			if (lapb->mode & LAPB_EXTENDED) {
#if LAPB_DEBUG > 1
				printk(KERN_DEBUG "lapb: (%p) S4 TX DM(%d)\n", lapb->token, frame->pf);
#endif
				lapb_send_control(lapb, LAPB_DM, frame->pf, LAPB_RESPONSE);
			} else {
#if LAPB_DEBUG > 1
				printk(KERN_DEBUG "lapb: (%p) S4 TX UA(%d)\n", lapb->token, frame->pf);
#endif
#if LAPB_DEBUG > 0
				printk(KERN_DEBUG "lapb: (%p) S4 -> S3\n", lapb->token);
#endif
				lapb_send_control(lapb, LAPB_UA, frame->pf, LAPB_RESPONSE);
				lapb_stop_t1timer(lapb);
				lapb_stop_t2timer(lapb);
				lapb->state     = LAPB_STATE_3;
				lapb->condition = 0x00;
				lapb->n2count   = 0;
				lapb->vs        = 0;
				lapb->vr        = 0;
				lapb->va        = 0;
				lapb_connect_indication(lapb, LAPB_OK);
			}
			break;

		case LAPB_SABME:
#if LAPB_DEBUG > 1
			printk(KERN_DEBUG "lapb: (%p) S4 RX SABME(%d)\n", lapb->token, frame->pf);
#endif
			if (lapb->mode & LAPB_EXTENDED) {
#if LAPB_DEBUG > 1
				printk(KERN_DEBUG "lapb: (%p) S4 TX UA(%d)\n", lapb->token, frame->pf);
#endif
#if LAPB_DEBUG > 0
				printk(KERN_DEBUG "lapb: (%p) S4 -> S3\n", lapb->token);
#endif
				lapb_send_control(lapb, LAPB_UA, frame->pf, LAPB_RESPONSE);
				lapb_stop_t1timer(lapb);
				lapb_stop_t2timer(lapb);
				lapb->state     = LAPB_STATE_3;
				lapb->condition = 0x00;
				lapb->n2count   = 0;
				lapb->vs        = 0;
				lapb->vr        = 0;
				lapb->va        = 0;
				lapb_connect_indication(lapb, LAPB_OK);
			} else {
#if LAPB_DEBUG > 1
				printk(KERN_DEBUG "lapb: (%p) S4 TX DM(%d)\n", lapb->token, frame->pf);
#endif
				lapb_send_control(lapb, LAPB_DM, frame->pf, LAPB_RESPONSE);
			}
			break;

		default:
			break;
	}

	kfree_skb(skb);
}

/*
 *	Process an incoming LAPB frame
 */
void lapb_data_input(lapb_cb *lapb, struct sk_buff *skb)
{
	struct lapb_frame frame;

	lapb_decode(lapb, skb, &frame);

	switch (lapb->state) {
		case LAPB_STATE_0:
			lapb_state0_machine(lapb, skb, &frame);
			break;
		case LAPB_STATE_1:
			lapb_state1_machine(lapb, skb, &frame);
			break;
		case LAPB_STATE_2:
			lapb_state2_machine(lapb, skb, &frame);
			break;
		case LAPB_STATE_3:
			lapb_state3_machine(lapb, skb, &frame);
			break;
		case LAPB_STATE_4:
			lapb_state4_machine(lapb, skb, &frame);
			break;
	}

	lapb_kick(lapb);
}