#include?“head.h“

/*?Set?expire?time?of?the?specified?record?*/
void?Set_ID_Expire（ID_Trans_Unit*?record?int?ttl）
{
????record->expire_time?=?time（NULL）?+?ttl;???/*?expire_time?=?time?now?+?time?to?live?*/
}

/*?Check?whether?the?record?is?expired?*/
int?Check_ID_Expired（ID_Trans_Unit*?record）
{
	return?record->expire_time?>?0?&&?time（NULL）?>?record->expire_time;
}

/*?Register?new?ID?into?ID_Trans_Table?*/
unsigned?short?Register_New_ID（unsigned?short?ID?SOCKADDR_IN?temp?BOOL?if_done）
{
????int?i?=?0;
????for?（i?=?0;?i?!=?MAX_ID_TRANS_TABLE_SIZE;?++i）
????{
????????/*?Find?out?overdue?record?or?a?record?which?was?analysed?completely?*/
????????if?（Check_ID_Expired（&ID_Trans_Table[i]）?==?1?||?ID_Trans_Table[i].done?==?TRUE）
????????{
????????????ID_Trans_Table[i].old_ID?=?ID;?????/*?Set?ID?*/
????????????ID_Trans_Table[i].client?=?temp;???/*?socket_addr?*/
????????????ID_Trans_Table[i].done?=?if_done;??/*?Mark?whether?analysis?completed?*/
????????????Set_ID_Expire（&ID_Trans_Table[i]?ID_EXPIRE_TIME）;
????????????ID_Count++;
????????????if?（debug_level）
			{
				printf（“New?ID?:?%d?registered?successfully\n“?i?+?1）;
				printf（“#ID?Count?:?%d\n“?ID_Count）;
			}
????????????break;
????????}
????}
????if?（i?==?MAX_ID_TRANS_TABLE_SIZE）?/*?Register?failed?*/
????????return?0;
????return?（unsigned?short）i?+?1;?/*?Return?new?ID?*/
}

/*?Convert?buf?content?to?url?and?save?into?dest?*/
void?Convert_to_Url?（char*?buf?char*?dest）
{
????int?i?=?0?j?=?0?k?=?0?len?=?strlen（buf）;
????while?（i?????{
????????if?（buf[i]?>?0?&&?buf[i]?<=?63）?/*?Count?*/
????????{
????????????for?（j?=?buf[i]?i++;?j?>?0;?j--?i++?k++）?/*?Copy?the?url?*/
????????????????dest[k]?=?buf[i];
????????}
????????if?（buf[i]?!=?0）?/*?If?this?is?not?the?end?put?a?dot?into?dest?*/
????????{
????????????dest[k]?=?‘.‘;
????????????k++;
????????}
????}
????dest[k]?=?‘\0‘;?/*?Set?the?end?*/
}

/*?Output?the?whole?packet?*/
void?Output_Packet（char?*bufint?length）
{
	unsigned?char?unit;
????printf（“Packet?length?=?%d\n“?length）;
	printf（“Details?of?the?package:\n“）;
	for（int?i?=?0;?i?	{
		unit?=（unsigned?char）buf[i];
		printf（“%02x?“?unit）;
	}
	printf（“\n“）;
}

/*?Receive?packet?from?exterior?*/
void?Receive_from_Extern（）
{
	char?buf[MAX_BUF_SIZE]?url[65];
	memset（buf?0?MAX_BUF_SIZE）;
????int?length?=?-1;
????length?=?recvfrom（extern_sock?buf?sizeof（buf）?0?（struct?sockaddr*）&external?&length_client）;?/*?Receive?DNS?packet?from?exterior?*/
????if?（length?>?-1）
????{
		if?（debug_level）
		{
			printf（“\n\n----?Recv?:?Extern?[IP:%s]----\n“?inet_ntoa（external.sin_addr））;

			/*?Output?time?now?*/
			time_t?t?=?time（NULL）;
			char?temp[64];
			strftime（temp?sizeof（temp）?“%Y/%m/%d?%X?%A“?localtime（&t））;
			printf（“%s\n“?temp）;

			if?（debug_level?==?2）
				Output_Packet（buf?length）;
		}

		/*?Get?ID?index?*/
????????unsigned?short?*pID?=?（unsigned?short?*）ma

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----
?????目錄???????????0??2019-06-15?23:28??1814陳斌-1815李奕陽-1816羅陽\
?????目錄???????????0??2019-06-15?23:28??1814陳斌-1815李奕陽-1816羅陽\可執行文件\
?????文件??????193536??2019-06-09?00:00??1814陳斌-1815李奕陽-1816羅陽\可執行文件\dnsrelay.exe
?????文件??????????80??2019-06-05?23:05??1814陳斌-1815李奕陽-1816羅陽\可執行文件\dnsrelay.txt
?????目錄???????????0??2019-06-15?23:28??1814陳斌-1815李奕陽-1816羅陽\源代碼文件\
?????文件??????????80??2019-06-05?23:05??1814陳斌-1815李奕陽-1816羅陽\源代碼文件\dnsrelay.txt
?????文件????????3726??2019-06-09?00:01??1814陳斌-1815李奕陽-1816羅陽\源代碼文件\head.h
?????文件???????14165??2019-06-09?00:01??1814陳斌-1815李奕陽-1816羅陽\源代碼文件\main.cpp
?????目錄???????????0??2019-06-15?23:28??1814陳斌-1815李奕陽-1816羅陽\設計報告\
?????文件?????4799488??2019-06-09?00:11??1814陳斌-1815李奕陽-1816羅陽\設計報告\1814陳斌-1815李奕陽-1816羅陽.doc
?????文件?????2131851??2019-06-09?00:11??1814陳斌-1815李奕陽-1816羅陽\設計報告\1814陳斌-1815李奕陽-1816羅陽.pdf