https TSL (SSL) client hello server hello浅析。

因为要做个拨测，需要拨测https，也就是要看是否能与https服务器正常通讯。

所以查了资料，结合wireshark分析了下，client hello 、server hello内容。

两个hello通讯的前43个字节，意义是相同的：

//https tls
struct ProtocolVersion{
  uint8_t major;
  uint8_t minor;
};
enum ContentType{
  change_cipher_spec=20, alert, handshake,
  application_data
};
enum handshake_type{
	clien_hello=1, server_hello
};
typedef struct {
	uint8_t type;//ContentType 不能用enum，因为enum的成员长度是4
	struct ProtocolVersion record_layer_version;
	uint16_t record_layer_length;
	uint8_t handshake_type;//handshake_type
	uint8_t unuse_flag;
	uint16_t handshake_length;
	struct ProtocolVersion handshake_version;
	uint32_t time_stamp;
	char random[28];
} TLSPlaintext;

再给一段生成client hello的代码，这个是根据firefox的抓包的出来的，很low但能用：

static int ssl_inited = 0;
			static char ssl_client_hello[256];
			if(ssl_inited==0){
				ssl_inited = sprintf(ssl_client_hello, "%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c%c",22,3,1,0,143,1,0,0,139,3,3,88,20,46,196,175,181,85,76,101,22,68,197,18,171,239,103,209,196,218,211,83,190,188,182,18,23,203,134,183,236,189,92,0,0,22,192,43,192,47,192,10,192,20,0,57,0,53,192,9,192,19,0,51,0,47,0,10,1,0,0,76,255,1,0,1,0,0,10,0,8,0,6,0,23,0,24,0,25,0,11,0,2,1,0,0,35,0,0,0,16,0,14,0,12,2,104,50,8,104,116,116,112,47,49,46,49,0,5,0,5,1,0,0,0,0,0,13,0,18,0,16,4,3,5,3,6,3,4,1,5,1,6,1,2,3,2,1);
			}
			str_len = ssl_inited;
			struct timeval tv;
			gettimeofday(&tv, NULL);
			memcpy(sendStr, ssl_client_hello, str_len);
			memcpy(sendStr+11, &tv.tv_sec, 4);
			int i;
			for(i=0;i<28;i++){
				sendStr[15+i] = (sendStr[15+i]&0xFF + tv.tv_usec) & 0xFF;
			}

把服务器返回的转为：TLSPlaintext*，即可获取相关的信息：

char server_response[512];

readMsg(fd, server_response, 511);

TLSPlaintext* tls_resp = (TLSPlaintext*) server_response;

，serverhello符合：

tls_resp->type==handshake && tls_resp->handshake_type==server_hello

https TSL (SSL) client hello server hello浅析。

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