ipv6地址转换

ipv6地址解析

/* ipv6 无符号整型数组转化为字符串 */
void ipv6_to_str(char *addr_str, unsigned int ipv6_addr[])
{
	/* ipv6地址128位，数组ip维数默认为4 */
	/* 输出格式为: A:B:C:D:E:F:G:H. */
	int i;
	unsigned short msw, lsw;
	char *addr_str_end_ptr;
	
	addr_str[0] = '\0';
	addr_str_end_ptr = addr_str;
	for (i = 0; i < 4; i++)
	{
		msw = ipv6_addr[i] >> 16;
		lsw = ipv6_addr[i] & 0x0000ffff;
		addr_str_end_ptr += sprintf(addr_str_end_ptr, "%X:%X:", msw, lsw); 
	}
	*(addr_str_end_ptr - 1) = '\0';
}


char * string_white_space_trim(char *str)
{
	/* 移除字符串中空格 */
	int index;
	int new_index;
	int str_length;
	
	str_length = strlen(str);
	
	for (index = 0, new_index = 0; index < str_length; index++)
	{
		if (!isspace((unsigned char)str[index]))
		{
			str[new_index] = str[index];
			new_index++;
		}
	}
	
	str[new_index] = '\0';
	
	return str;
}

int string_char_count(const char *string, char character)
{
	/* 计算字符串中，给定字符的数量 */
	int i;
	int str_length;
	int count = 0;
	
	str_length = strlen(string);
	for (i = 0; i < str_length; i++)
	{
		if (string[i] == character)
		{
			count++;
		}
	}
	
	return count;
}

int ipv6_address_field_type_get(const char * field_str)
{
	/* 判断ipv6地址域类型                           */
	int i = 0;
	int length;
	int type;
	unsigned int ipv4_addr;
	
	/* 通过长度判断          */
	/* 16进制数字域： 1-4    */
	/* "::"域：0             */
	/* ipv4地址域： 7-15     */
	
	length = strlen(field_str);
	
	if (0 == length)
	{
		type = 1;
	}
	else if (length <= 4)
	{
		// 确保每个数字为16进制
		for (i = 0; i < length; i++)
		{
			if (!isxdigit((unsigned char)field_str[i]))
			{
				return -1;
			}
		}
		type = 0;
	}
	else if((length >= 7) && (length <= 15))
	{
		//确保是有效的ipv4地址
		if (ipv4_to_i(field_str, &ipv4_addr))
		{
			type = 2;
		}
		else
		{
			type = -1;
		}
	}
	else
	{
		type = -1;
	}
	
	return type;
}

int ipv6_to_i(const char *addr_str, int length, unsigned int ipv6_addr_ptr[])
{
	/***************************************************************************/
	/* 功能：解析ipv6地址字符串，转换为无符号整形,存入4个无符号整形的一维数组  */
	/* ipv6地址 128位，prefix length:                 									  */
	/*                         - 64 for EUI-64 addresses                       */
	/*                         - 128 for non-EUI-64 addresses                  */
	/* 输入：ipv6地址字符串，地址位数，默认为128位                             */
	/* 输出：返回解析成功或失败;指向4个无符号整形的一维数组的指针              */
	/****************************************************************************/
	
	char addr_str_copy[256];
	int i, num_fields;
	//unsigned int *ret_addr_ptr;
	unsigned short int addr_field_arr[8];
	int addr_index;
	char *ith_field; // 指向地址当前域
	int  ith_field_type; // 地址域类型
	char *next_field;
	int  double_colon_field_index = -1; // 字符串地址中"::"的位置
	unsigned int ipv4_address; // ipv6地址中的ipv4部分
	unsigned int msw, lsw;
	int error = 0;
	
	//复制一份，以便操作
	strcpy(addr_str_copy, addr_str);
	
	// 移除字符串中的空格字符
	string_white_space_trim(addr_str_copy);
	
	/* IPv6地址可能几种格式：                                          */
	/* 1) 2006:DB8:2A0:2F3B:34:E35:45:1   用16进制表示每个域的值(16位) */
	/* 2) 2006:DB8::E34:1 , "::" 代表0，且只能出现一次       */
	/* 3) 2002:9D36:1:2:0:5EFE:192.168.12.9 带有ipv4地址     */
	
	// 计算字符串中冒号，字符串中地址域数比冒号多一个
	num_fields = string_char_count(addr_str_copy, ':') + 1;
	
	// 域最大数量为length/16 + 2
	// 如  ::0:0:0:0:0:0:0:0.
	if (num_fields > ((length >> 4) + 2))
	{
		ipv6_addr_ptr = NULL;
		return 0;
	}
	
	// 初始化
	ith_field = addr_str_copy;
	
	for (i = 0, addr_index = 0; i < num_fields; i++)
	{
		// 获得下一个域的指针
		next_field = strchr(ith_field, ':');
		
		/* 若当前是最后一个域, next_field 是 NULL                       */
		/* 否则，替换':'为'\0', 字符串可以结束，从而ith_field指向当前域   */
		/* next_field指向下一个域头部                                    */
		if (NULL != next_field)
		{
			*next_field = '\0';
			++next_field;
		}
		
		// 发现这个域的类型
		ith_field_type = ipv6_address_field_type_get(ith_field);
		
		switch (ith_field_type)
		{
			case 0:
			// 域类型为16进制表示
				
				if (addr_index >= (length >> 4))
				{
					error = 1;
					break;
				}
				// 字符串转换为16进制
				addr_field_arr[addr_index] = (unsigned short)strtoul(ith_field, NULL, 16);
				++addr_index;
			break;
			
			case 1:
			// 域类型为 "::"
			
				// 若出现在字符串的开头或结尾，忽略
				if ((0 == i) || (i == num_fields - 1))
				{
					break;
				}
				
				// 若出现大于一次，错误
				if (double_colon_field_index != -1)
				{
					error = 1;
					break;
				}
			
				// 记下位置
				double_colon_field_index = addr_index;
			
			break;
			
			case 2:
			// 域类型为ipv4地址
			
				// 确保在地址中还有两个未设置的域
				if (addr_index >= 7)
				{
					error = 1;
					break;
				}
				
				// ipv4地址解析
				ipv4_to_i(ith_field, &ipv4_address);
				
				// 存储高16位
				addr_field_arr[addr_index] = (unsigned short)(ipv4_address >> 16);
				
				// 存储低16位
				addr_field_arr[addr_index + 1] = (unsigned short)(ipv4_address & 0x0000ffff);
				
				addr_index += 2;
			
			break;
			default:
				error = 1;
			break;
		}
		
		if (error)
		{
			ipv6_addr_ptr = NULL;
			return 0;
		}
		
		ith_field = next_field;
	}
	
	// 计算的域不是8，并且没有"::",错误
	if ((addr_index != (length >> 4)) && (-1 == double_colon_field_index))
	{
		ipv6_addr_ptr = NULL;
		return 0;
	}
	
	if ((addr_index != (length >> 4)) && (-1 != double_colon_field_index))
	{
		// 设置相应"::"对应addr_field_arr中位置为0
		memmove(addr_field_arr + (double_colon_field_index + (length >> 4) - addr_index),
					addr_field_arr + double_colon_field_index, (addr_index - double_colon_field_index) * 2);
		memset(addr_field_arr + double_colon_field_index, 0, ((length >> 4) - addr_index) * 2);
	}
	
	for (i = 0; i < 4; i++)
	{
		msw = addr_field_arr[2 * i];
		lsw = addr_field_arr[2 * i + 1];
		
		(ipv6_addr_ptr)[i] = (msw << 16 | lsw);
	}
	
	return 1;
}

int main()
{
	char addr[256];
	unsigned int ip_v4 = 3356567252;
	unsigned int ipv6[4] = {3356567252, 3356567253, 3356567254, 3356567255};
	unsigned int ipv61[4] = {65538, 196612, 327686, 458760};
	char *ipv6_str1 = "1:2:3:4:5:6:7:8";
	char *ipv6_str2 = "1:2:3:4:5:6:7:8::";
	char *ipv6_str3 = "::1:2:3:4:5:6:7:8";
	char *ipv6_str4 = "1:2:3:4:5:6:192.168.1.100";
	char *ipv6_str5 = "1:2::5:6:7:8";
	char *ipv6_str6 = "1::3:4:5:6:7:8";
	char *ipv6_str7 = "1::4:5:6:7:8";
	char *ipv6_str8 = "1::8";

	unsigned int ipv6_addr[4];
	unsigned int ipv4_addr;
	int flag;
	int i;
    // 192.168.1.100-----3232235876
//	ipv4_to_str(addr, ip_v4);
//	printf("ipv4: %s\n", addr);

	ipv6_to_str(addr, ipv61);
	printf("ipv6: %s\n", addr);

	flag = ipv4_to_i("192.168.1.100", &ipv4_addr);
	if (flag)
	{
		printf("ipv4_addr: %u\n", ipv4_addr);
	}

	flag = ipv6_to_i(ipv6_str8, 128, ipv6_addr);
	if (flag)
	{
		for (i = 0; i < 4; i++)
		{
			printf("ipv6_addr: %u\n", ipv6_addr[i]);
		}
		
	}

	return 0;
}