#include?
#include?

#include?“protocol.h“

#define?MAX_SEQ?15??????????????????//最大的窗口大小
#define?NR_BUFS?（（MAX_SEQ?+?1）?/?2）?????//緩沖區(qū)大小

#define?DATA_TIMER??3000???????//幀超時(shí)時(shí)間間隔
#define?ACK_TIMER?240??????????//ack的超時(shí)間隔

struct?frame?{?
	//數(shù)據(jù)幀的結(jié)構(gòu)體定義
????unsigned?char?kind;
????unsigned?char?ack;
????unsigned?char?seq;
????unsigned?char?data[PKT_LEN];?
????unsigned?int??padding;
};

int?no_nak=1;							//標(biāo)志是否已經(jīng)發(fā)送過(guò)nak
static?int?phl_ready?=?0;				//物理層就緒標(biāo)記
unsigned?char?oldest_frame?=?MAX_SEQ?+?1;	//

static?int?between（unsigned?char?aunsigned?char?bunsigned?char?c）??
//滑動(dòng)窗口判斷函數(shù)，判斷幀號(hào)（ack號(hào)）是否在窗口內(nèi)
{
???if（（（a?<=?b）?&&?（b?		return?1;
	else
		return?0;

}

static?void?put_frame（unsigned?char?*frame?int?len）
{
	//發(fā)送幀前預(yù)處理，加入校驗(yàn)和crc
????*（unsigned?int?*）（frame?+?len）?=?crc32（frame?len）;//crc32校驗(yàn)
????send_frame（frame?len?+?4）;//發(fā)送幀
????phl_ready?=?0;//設(shè)置物理層阻塞
}

static?void?send_data_frame（unsigned?char?fkunsigned?char?frame_nrunsigned?char?frame_expectedunsigned?char?buffer[NR_BUFS][PKT_LEN]）
{
	//發(fā)送數(shù)據(jù)幀，或ack與nak
????struct?frame?s;
????
????s.kind?=?fk;
????s.seq?=?frame_nr;
????s.ack?=?（frame_expected?+?MAX_SEQ）?%?（MAX_SEQ?+?1）;

	if（fk==frame_DATA）//發(fā)送的是數(shù)據(jù)幀
	{
		memcpy（s.data?buffer[frame_nr?%?NR_BUFS]?PKT_LEN）;//復(fù)制分組到幀內(nèi)
		dbg_frame（“Send?DATA?%d?%d?ID?%d\n“?s.seq?s.ack?*（short?*）s.data）;//輸出記錄
????????put_frame（（unsigned?char?*）&s?3?+?PKT_LEN）;???//發(fā)送
		start_timer（frame_nr?%?NR_BUFS?DATA_TIMER）;?????//啟動(dòng)定時(shí)器
	}
	else?if（fk?==?frame_NAK）//發(fā)送的是NAK
	{
		no_nak?=?0;?????????????????????????????????????//下一次不再發(fā)送nak
	????put_frame（（unsigned?char?*）&s?3）;????????????//發(fā)送
	}
	else?if（fk?==?frame_ACK）//發(fā)送的是ACK
	{
		dbg_frame（“Send?ACK??%d\n“?s.ack）;//輸出記錄
????????put_frame（（unsigned?char?*）&s?3）;//發(fā)送
	}
	phl_ready?=?0;							//物理層阻塞
	stop_ack_timer（）;???????????????????????//關(guān)閉ack定時(shí)器
}

void?main（int?argc?char?**argv）
{
	int?event?arg;
????struct?frame?f;
????int?len?=?0;
????int?i;
	static?unsigned?char?ack_expected?=?0?next_frame_to_send?=?0;//當(dāng)前幀和下一期望幀的序號(hào)
	static?unsigned?char?frame_expected?=?0?too_far?=?NR_BUFS;
????static?unsigned?char?nbuffered;
	int?arrived[NR_BUFS];//緩沖區(qū)，存放到達(dá)的幀
	static?unsigned?char?out_buf[NR_BUFS][PKT_LEN]?in_buf[NR_BUFS][PKT_LEN];

????protocol_init（argc?argv）;//初始化協(xié)議

????lprintf（“Coded?by?zdf?Build?Time:?“?__DATE__“??“__TIME__“\n“）;

	for（i?=?0;?i?		arrived[i]?=?0;

????enable_network_layer（）;//啟動(dòng)網(wǎng)絡(luò)層，準(zhǔn)備接收數(shù)據(jù)

	while（1）
	{
		event?=?wait_for_event（&arg）;			//等待事件，進(jìn)行下一步操作
		switch?（event）
		{
			case?NETWORK_layer_READY:
				nbuffered++;????????????????????//發(fā)送卻未被確認(rèn)的幀計(jì)數(shù)器+1
				get_packet（out_buf[next_frame_to_send?%?NR_BUFS]）;//得到分組存入緩沖區(qū)內(nèi)
				send_data_frame（frame_DATAnext_frame_to_sendframe_expectedout_buf）;//發(fā)送數(shù)據(jù)幀
				next_frame_to_send=（next_frame_to_send?+?1）?%?（?MAX_SEQ?+?1）;//處理滑動(dòng)窗口
				break;

?屬性????????????大小?????日期????時(shí)間???名稱
-----------?---------??----------?-----??----

?????文件??????35647??2015-05-24?14:16??Selective\datalink-A.log

?????文件??????46710??2015-05-24?14:16??Selective\datalink-B.log

?????文件???????6152??2015-05-24?13:51??Selective\datalink.c

?????文件???????3476??2009-10-19?16:46??Selective\datalink.dsp

?????文件????????524??2009-10-16?10:23??Selective\datalink.dsw

?????文件?????500736??2015-05-24?13:52??Selective\datalink.exe

?????文件????????518??2009-10-16?12:34??Selective\datalink.h

?????文件????1095776??2015-05-24?13:52??Selective\datalink.ilk

?????文件??????50176??2009-11-28?19:29??Selective\datalink.ncb

?????文件???????4493??2015-05-19?13:31??Selective\datalink.o

?????文件??????48640??2009-11-28?19:29??Selective\datalink.opt

?????文件????2617344??2015-05-24?13:52??Selective\datalink.pdb

?????文件????????250??2009-11-28?19:00??Selective\datalink.plg

?????文件????2031616??2015-05-24?14:16??Selective\datalink.sdf

?????文件????????961??2015-05-19?15:20??Selective\datalink.sln

????..A..H.?????19456??2015-05-24?14:16??Selective\datalink.v12.suo

?????文件???????6293??2015-05-19?13:32??Selective\datalink.vcxproj

?????文件???????1445??2015-05-24?13:52??Selective\Debug\datalink.log

?????文件??????13592??2015-05-24?13:52??Selective\Debug\datalink.obj

?????文件????????616??2015-05-24?13:52??Selective\Debug\datalink.tlog\cl.command.1.tlog

?????文件????????980??2015-05-24?13:52??Selective\Debug\datalink.tlog\CL.read.1.tlog

?????文件????????384??2015-05-24?13:52??Selective\Debug\datalink.tlog\CL.write.1.tlog

?????文件????????164??2015-05-24?13:52??Selective\Debug\datalink.tlog\datalink.lastbuildstate

?????文件???????1084??2015-05-24?13:52??Selective\Debug\datalink.tlog\link.command.1.tlog

?????文件???????2694??2015-05-24?13:52??Selective\Debug\datalink.tlog\link.read.1.tlog

?????文件????????464??2015-05-24?13:52??Selective\Debug\datalink.tlog\link.write.1.tlog

?????文件??????27648??2015-05-24?13:52??Selective\Debug\vc120.idb

?????文件??????77824??2015-05-24?13:52??Selective\Debug\vc120.pdb

?????文件??????41984??2009-11-28?19:01??Selective\Debug\vc60.idb

?????文件??????53248??2009-11-28?19:00??Selective\Debug\vc60.pdb

............此處省略22個(gè)文件信息