• 基于reactor设计websocket服务器

    目录

    1.什么是WebSocket？

    2.总体过程：

    2.1 握手过程：

    2.2 接收和发送

    3. 完整代码

    4.运行结果

    总结：

    1.什么是WebSocket？

            WebSocket是HTML5下一种新的协议（websocket协议本质上是一个基于tcp的协议）

            websocket使得客户端和服务器之间的数据交换变得更加简单，允许服务端主动向客户端推送数据。在WebSocket API中，浏览器和服务器只需要完成一次握手，两者之间就直接可以创建持久性的连接，并进行双向数据传输。

    2.总体过程：

    2.1 握手过程：

            首先，客户端发起http请求，经过3次握手后，建立起TCP连接；http请求里存放WebSocket支持的版本号等信息，如：Upgrade、Connection、WebSocket-Version等；

            然后，服务器收到客户端的握手请求后，同样采用HTTP协议回馈数据；最后，客户端收到连接成功的消息后，开始借助于TCP传输信道进行全双工通信。

            第一个一条信息来自|Sec-WebSocket-Key|报头字段在客户端握手中:Sec-WebSocket-Key: fmXyv9eR4PG9L53s09jQLA==对于这个报头字段，服务器必须接受该值(作为当前值)在报头字段中，例如，base64编码的[RFC4648]版本减任何前导和尾随空格)，并将其与全局唯一标识符(GUID， [RFC4122])“258 eafa5-e914-47da -95CA-C5AB0DC85B11”的字符串形式，不太可能被使用网络端点不理解WebSocket协议。一个SHA-1哈希(160位)[FIPS;180-3]，base64编码，然后返回到服务器的握手。

    1. ###websocket  浏览器-->服务器
    2. GET / HTTP/1.1
    3. Host: 192.168.240.128:8888
    4. Connection: Upgrade ##升级版
    5. Pragma: no-cache
    6. Cache-Control: no-cache
    7. User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/94.0.4606.71 Safari/537.36 Core/1.94.172.400 QQBrowser/11.1.5140.400
    8. Upgrade: websocket #websockrt
    9. Origin: null
    10. Sec-WebSocket-Version: 13
    11. Accept-Encoding: gzip, deflate
    12. Accept-Language: zh-CN,zh;q=0.9
    13. Sec-WebSocket-Key: fmXyv9eR4PG9L53s09jQLA==
    14. Sec-WebSocket-Extensions: permessage-deflate; client_max_window_bits
    15.  
    16.  
    17. ###握手信息拼接Key+GUID
    18. Key =  fmXyv9eR4PG9L53s09jQLA==
    19. GUID = 258EAFA5-E914-47DA-95CA-C5AB0DC85B11
    20. str = Key+GUID = fmXyv9eR4PG9L53s09jQLA==258EAFA5-E914-47DA-95CA-C5AB0DC85B11
    21.  
    22. ###哈希SHA-1
    23. sha = SHA-1(str)
    24. ###base64转换
    25. vaule = base64-encoded(sha);
    26.  
    27. ###服务器-->浏览器
    28. HTTP/1.1 101 Switching Protocols
    29. Upgrade: websocket
    30. Connection: Upgrade
    31. Sec-WebSocket-Accept: vaule

    具体代码实现

    1. //响应包拼接
    2. int ws_handshark(struct ntyevent *ev) 
    3. {
    4. 	int idx = 0;
    5. 	char sec_data[128] = {0};
    6. 	char sec_accept[128] = {0};
    7.  
    8. 	do{
    9. 		char linebuff[1024] = {0};	
    10. 		idx = readline(ev->buffer, idx, linebuff);
    11.  
    12. 		if(strstr(linebuff, "Sec-WebSocket-Key") > 0){
    13. 			//Sec-WebSocket-Key: hGI6OP19pWseAnpMcEnb2g==
    14. 			//Key+GUID
    15. 			//Sec-WebSocket-Key: hGI6OP19pWseAnpMcEnb2g==258EAFA5-E914-47DA-95CA-C5AB0DC85B11
    16. 			strcat(linebuff, GUID);
    17.  
    18. 			//哈希SHA-1			
    19. 			SHA1(linebuff + strlen("Sec-WebSocket-Key: "), strlen(linebuff + strlen("Sec-WebSocket-Key: ")), sec_data);
    20.  
    21. 			//base64 编码
    22. 			base64_encode(sec_data, strlen(sec_data), sec_accept);	
    23.  
    24. 			//printf("idx: %d, line: %ld\n",idx, sizeof("Sec-WebSocket-Key: "));
    25. 			//printf("idx: %d, line: %ld\n",idx, strlen("Sec-WebSocket-Key: "));
    26.  
    27. 			printf("idx %d ; line:%s\n", idx, sec_accept);
    28. 			memcpy(ev->sec_accept, sec_accept, ACCEPT_KEY_LENGTH);
    29. 			
    30. 		}
    31. 		//printf("line %d ; line:%s\n", idx, linebuff);
    32. 	}while((ev->buffer[idx] != '\r' || ev->buffer[idx + 1] != '\n') && idx != -1); //两组\r\n结束
    33. 	return 0;
    34. }
    35.  
    36. //应答 #服务器-->浏览器
    37. int ws_response(struct ntyevent* ev)
    38. {
    39. 	ev->wlength = sprintf(ev->wbuffer, "HTTP/1.1 101 Switching Protocols\r\n"
    40. 						"Upgrade: websocket\r\n"
    41. 						"Connection: Upgrade\r\n"
    42. 						"Sec-WebSocket-Accept: %s\r\n\r\n", ev->sec_accept);
    43.  
    44. 	printf("response: %s\n", ev->wbuffer);
    45. 	return ev->wlength;
    46. }

    2.2 接收和发送

    websocket协议的数据帧

     FIN :1bit

    指示这是消息中的最后一个片段。第一个碎片也可能是最后的碎片。

    RSV1、RSV2、RSV3:各1bit

    必须为0，除非协商一个定义含义的扩展为非零值。如果接收到一个非零值，并且没有

    协商好的扩展定义了这种非零的含义值，接收端点必须失败WebSocketConnection.

    Opcode: 4 bits

    定义“有效负载数据”的解释。如果一个未知的操作码，接收端点必须失败WebSocket Connection_。定义了以下值。

    * %x0  表示延续帧

    * %x1  表示文本框架

    * %x2  表示二进制帧

    * %x3-7 为其他非控制帧保留

    * %x8 表示连接关闭

    * %x9 表示ping

    * %xA 表示pong

    * %xB-F  为进一步的控制帧保留

    Mask: 1 bit

    定义是否屏蔽“有效负载数据”。如果设置为1，则a屏蔽键包含在屏蔽键中，用于解除屏蔽。

    解除屏蔽

    j = i MOD 4

    transformed-octet-i = original-octet-i XOR masking-key-octet-j

    Payload length: 7 bits, 7+16 bits, or 7+64 bits

    “有效载荷数据”的长度，以字节为单位:如果0-125，则为有效载荷长度。如果126，下面的2个字节被解释为a16位无符号整数是有效载荷长度。如果127,后面的8个字节被解释为64位无符号整数最有效位必须为0)为有效载荷长度。多字节长度量用网络字节顺序表示。请注意,在所有情况下，必须使用最小字节数进行编码长度。

     将数据帧映射到结构体，小端字节序

    1. struct ws_ophdr {  //小端
    2.  
    3. 	unsigned char opcode:4,
    4. 				rsv3:1,
    5. 				rsv2:1,
    6. 				rsv1:1,
    7. 				fin:1;
    8.  
    9. 	unsigned char pl_len:7,
    10. 	 			  mask:1;
    11.  
    12. };

     具体代码

    1. //Masking-key, if MASK set to 1 解除数据屏蔽
    2. void umask(char *payload, int length, char *mask_key) {
    3.  
    4. 	int i = 0;
    5.  
    6. 	for (i = 0;i < length;i ++) {
    7. 		payload[i] ^= mask_key[i%4];
    8. 	}
    9.  
    10. }
    11.  
    12. int ws_tranmission(struct ntyevent *ev) 
    13. {
    14. 	struct ws_ophdr *hdr = (struct ws_ophdr *)ev->buffer;
    15.  
    16. 	if (hdr->pl_len < 126) {
    17.  
    18. 		unsigned char *payload = NULL;
    19. 		if (hdr->mask) {
    20. 			payload = ev->buffer + 6;
    21.  
    22. 			umask(payload, hdr->pl_len, ev->buffer + 2);
    23. 		} else {
    24. 			payload = ev->buffer + 2;
    25. 		}
    26.  
    27. 		printf("payload: %s\n", payload);
    28.  
    29. 	} else if (hdr->pl_len == 126) {
    30.  
    31. 	} else if (hdr->pl_len == 127)  {
    32.  
    33. 	} else {
    34. 		//assert(0);
    35. 	}
    36.  
    37. 	return 0;
    38. }

    3. 完整代码

    1. //gcc reactor_server_websocket.c -o server  -lssl -lcrypto
    2. #include 
    3. #include 
    4. #include 
    5. #include 
    6. #include 
    7. #include 
    8. #include 
    9. #include 
    10. #include 
    11.  
    12. #include 
    13. #include 
    14. #include 
    15. #include 
    16.  
    17.  
    18. #define GUID  "258EAFA5-E914-47DA-95CA-C5AB0DC85B11"
    19.  
    20. //状态机
    21. enum {
    22. 	WS_HANDSHARK = 0,    	//握手状态
    23. 	WS_TRANMISSION = 1,		//数据传输
    24. 	WS_END = 2,				//终止传输
    25. 	WS_COUNT
    26. };
    27.  
    28.  
    29. struct ws_ophdr {  //小端
    30.  
    31. 	unsigned char opcode:4,
    32. 				rsv3:1,
    33. 				rsv2:1,
    34. 				rsv1:1,
    35. 				fin:1;
    36.  
    37. 	unsigned char pl_len:7,
    38. 	 			  mask:1;
    39.  
    40. };
    41.  
    42.  
    43. #define  BUFFER_LENGTH  	1024
    44. #define  ACCEPT_KEY_LENGTH		64
    45.  
    46. #define  MAX_EPOLL_EVENTS   1024  //epoll事件数量
    47. #define  SERVER_PORT  		8888
    48. #define  PORT_COUNT			1
    49.  
    50. typedef int NCALLBACK(int ,int ,void*);
    51.  
    52. //管理每一个io fd的结构体
    53. struct ntyevent{
    54. 	int fd; //io fd
    55. 	int events;
    56. 	void *arg;
    57. 	int (*callback)(int fd, int events, void* arg); //执行回调函数
    58.  
    59. 	int status;	//判断是否已有事件
    60. 	char buffer[BUFFER_LENGTH]; //用户缓冲区 //request
    61. 	int length; //用户缓冲区长度
    62.  
    63. 	char wbuffer[BUFFER_LENGTH]; //response
    64. 	int wlength;
    65. 	
    66. 	char sec_accept[ACCEPT_KEY_LENGTH];
    67.  
    68. 	int wsstatus; //0, 1, 2, 3 描述状态机
    69. };
    70.  
    71. //管理ntyevent fd的块
    72. struct eventblock{
    73. 	struct eventblock* next; //指向ntyevent fd集合
    74. 	struct ntyevent* events; //指向下一个ntyevent fd的块
    75. };
    76.  
    77. //reacotr结点
    78. struct ntyreactor{
    79. 	int epfd;	//epoll fd
    80. 	int blkcnt;	//ntyevent fd的块 计数
    81.  
    82. 	struct eventblock* evblks;	//指向ntyevent fd的块头结点
    83. };
    84.  
    85. int recv_cb(int fd, int events, void *arg);
    86. int send_cb(int fd, int events, void *arg);
    87. int accept_cb(int fd, int events, void* arg);
    88.  
    89. struct ntyevent *ntyreactor_idx(struct ntyreactor *reactor, int sockfd);
    90.  
    91. //io fd结构体设置
    92. void nty_event_set(struct ntyevent* ev, int fd, NCALLBACK callback, void* arg)
    93. {
    94. 	ev->fd = fd;
    95. 	ev->callback = callback;
    96. 	ev->events = 0;
    97. 	ev->arg = arg;
    98.  
    99. 	return ;
    100. }
    101.  
    102. //io fd add
    103. int nty_event_add(int epfd, int events, struct ntyevent *ev)
    104. {
    105. 	struct epoll_event ep_ev = {0, {0}};
    106. 	ep_ev.data.ptr = ev;				//io fd结构体
    107. 	ep_ev.events = ev->events = events; //需要检测的fd事件
    108.  
    109. 	int op; //操作类型
    110. 	if(ev->status == 1){
    111. 		op = EPOLL_CTL_MOD; //修改
    112. 	}else{
    113. 		op = EPOLL_CTL_ADD; //添加
    114. 		ev->status = 1;		//标志已经添加
    115. 	}
    116. 		
    117. 	if(epoll_ctl(epfd, op, ev->fd, &ep_ev) <0 ){ //绑定
    118. 		printf("event add failed [fd=%d], events[%d]\n", ev->fd, events);
    119. 		return -1;
    120. 	}
    121.  
    122. 	return 0;
    123. }
    124.  
    125. //io fd del
    126. int nty_event_del(int epfd, struct ntyevent* ev)
    127. {
    128. 	struct epoll_event ep_ev = {0, {0}};
    129. 	if(ev->status != 1){ //没有添加过检测的fd事件
    130. 		return -1;
    131. 	}
    132.  
    133. 	ep_ev.data.ptr = ev;
    134. 	ev->status = 0; //标志未添加
    135. 	epoll_ctl(epfd, EPOLL_CTL_DEL, ev->fd, &ep_ev);
    136. 	return 0;
    137. }
    138.  
    139. //读行
    140. int readline(char* allbuf, int idx, char* linebuf)
    141. {
    142. 	int len = strlen(allbuf);
    143.  
    144. 	for(; idx < len; idx++){
    145. 		if(allbuf[idx] == '\r' && allbuf[idx+1] == '\n')
    146. 			return idx+2;
    147. 		else
    148. 			*(linebuf++) = allbuf[idx];
    149. 	}
    150. 	return -1;
    151. }
    152.  
    153. int base64_encode(char *in_str, int in_len, char *out_str) {    
    154. 	BIO *b64, *bio;    
    155. 	BUF_MEM *bptr = NULL;    
    156. 	size_t size = 0;    
    157.  
    158. 	if (in_str == NULL || out_str == NULL)        
    159. 		return -1;    
    160.  
    161. 	b64 = BIO_new(BIO_f_base64());    
    162. 	bio = BIO_new(BIO_s_mem());    
    163. 	bio = BIO_push(b64, bio);
    164. 	
    165. 	BIO_write(bio, in_str, in_len);    
    166. 	BIO_flush(bio);    
    167.  
    168. 	BIO_get_mem_ptr(bio, &bptr);    
    169. 	memcpy(out_str, bptr->data, bptr->length);    
    170. 	out_str[bptr->length-1] = '\0';    
    171. 	size = bptr->length;    
    172.  
    173. 	BIO_free_all(bio);    
    174. 	return size;
    175. }
    176.  
    177. //握手流程
    178. int ws_handshark(struct ntyevent *ev) 
    179. {
    180. 	int idx = 0;
    181. 	char sec_data[128] = {0};
    182. 	char sec_accept[128] = {0};
    183.  
    184. 	do{
    185. 		char linebuff[1024] = {0};	
    186. 		idx = readline(ev->buffer, idx, linebuff);
    187.  
    188. 		if(strstr(linebuff, "Sec-WebSocket-Key") > 0){
    189. 			//Sec-WebSocket-Key: hGI6OP19pWseAnpMcEnb2g==
    190. 			//Key+GUID
    191. 			//Sec-WebSocket-Key: hGI6OP19pWseAnpMcEnb2g==258EAFA5-E914-47DA-95CA-C5AB0DC85B11
    192. 			strcat(linebuff, GUID);
    193.  
    194. 			//哈希SHA-1			
    195. 			SHA1(linebuff + strlen("Sec-WebSocket-Key: "), strlen(linebuff + strlen("Sec-WebSocket-Key: ")), sec_data);
    196.  
    197. 			//base64 编码
    198. 			base64_encode(sec_data, strlen(sec_data), sec_accept);	
    199.  
    200. 			//printf("idx: %d, line: %ld\n",idx, sizeof("Sec-WebSocket-Key: "));
    201. 			//printf("idx: %d, line: %ld\n",idx, strlen("Sec-WebSocket-Key: "));
    202.  
    203. 			printf("idx %d ; line:%s\n", idx, sec_accept);
    204. 			memcpy(ev->sec_accept, sec_accept, ACCEPT_KEY_LENGTH);
    205. 			
    206. 		}
    207. 		//printf("line %d ; line:%s\n", idx, linebuff);
    208. 	}while((ev->buffer[idx] != '\r' || ev->buffer[idx + 1] != '\n') && idx != -1); //两组\r\n结束
    209. 	return 0;
    210. }
    211.  
    212. //Masking-key, if MASK set to 1 解除数据屏蔽
    213. void umask(char *payload, int length, char *mask_key) {
    214.  
    215. 	int i = 0;
    216.  
    217. 	for (i = 0;i < length;i ++) {
    218. 		payload[i] ^= mask_key[i%4];
    219. 	}
    220.  
    221. }
    222.  
    223. int ws_tranmission(struct ntyevent *ev) 
    224. {
    225. 	struct ws_ophdr *hdr = (struct ws_ophdr *)ev->buffer;
    226.  
    227. 	if (hdr->pl_len < 126) {
    228.  
    229. 		unsigned char *payload = NULL;
    230. 		if (hdr->mask) {
    231. 			payload = ev->buffer + 6;
    232.  
    233. 			umask(payload, hdr->pl_len, ev->buffer + 2);
    234. 		} else {
    235. 			payload = ev->buffer + 2;
    236. 		}
    237.  
    238. 		printf("payload: %s\n", payload);
    239.  
    240. 	} else if (hdr->pl_len == 126) {
    241.  
    242. 	} else if (hdr->pl_len == 127)  {
    243.  
    244. 	} else {
    245. 		//assert(0);
    246. 	}
    247.  
    248. 	return 0;
    249. }
    250.  
    251. //请求 协议解析
    252. int ws_request(struct ntyevent * ev)
    253. {
    254. 	if (ev->wsstatus == WS_HANDSHARK) {
    255. 		ws_handshark(ev);
    256. 		ev->wsstatus = WS_TRANMISSION;  //状态改变
    257. 	} else if (ev->wsstatus == WS_TRANMISSION) {
    258. 		ws_tranmission(ev);
    259. 	}
    260. }
    261.  
    262.  
    263.  
    264. //应答 #服务器-->浏览器
    265. int ws_response(struct ntyevent* ev)
    266. {
    267. 	ev->wlength = sprintf(ev->wbuffer, "HTTP/1.1 101 Switching Protocols\r\n"
    268. 						"Upgrade: websocket\r\n"
    269. 						"Connection: Upgrade\r\n"
    270. 						"Sec-WebSocket-Accept: %s\r\n\r\n", ev->sec_accept);
    271.  
    272. 	printf("response: %s\n", ev->wbuffer);
    273. 	return ev->wlength;
    274. }
    275.  
    276.  
    277.  
    278. //recv回调
    279. int recv_cb(int fd, int events, void* arg)
    280. {
    281. 	struct ntyreactor* reactor = (struct ntyreactor*)arg;
    282. 	struct ntyevent* ev = ntyreactor_idx(reactor, fd);	
    283.  
    284. 	if(ev == NULL)return -1;
    285.  
    286. 	int len = recv(fd, ev->buffer, BUFFER_LENGTH, 0);
    287. 	nty_event_del(reactor->epfd, ev);
    288.  
    289. 	if (len > 0) {
    290. 		
    291. 		ev->length = len;
    292. 		ev->buffer[len] = '\0';
    293.  
    294. 		//printf("recv [%d]:%s\n", fd, ev->buffer);
    295.  
    296. 		ws_request(ev);
    297.  
    298. 		//将fd 设置为发送事件
    299. 		nty_event_set(ev, fd, send_cb, reactor);
    300. 		nty_event_add(reactor->epfd, EPOLLOUT, ev);
    301. 		
    302. 		
    303. 	} else if (len == 0) {  //客户端断开连接
    304.  
    305. 		nty_event_del(reactor->epfd, ev);
    306. 		printf("recv_cb --> disconnect\n");
    307. 		close(ev->fd);
    308. 		 
    309. 	} else { //返回错误
    310.  
    311. 		if (errno == EAGAIN && errno == EWOULDBLOCK) { //
    312. 			
    313. 		} else if (errno == ECONNRESET){
    314. 			nty_event_del(reactor->epfd, ev);
    315. 			close(ev->fd);
    316. 		}
    317. 		printf("recv[fd=%d] error[%d]:%s\n", fd, errno, strerror(errno));
    318. 		
    319. 	}
    320.  
    321. 	return len;
    322. }
    323.  
    324.  
    325.  
    326. //send回调
    327. int send_cb(int fd, int events, void* arg)
    328. {
    329. 	struct ntyreactor* reactor = (struct ntyreactor*)arg;
    330. 	struct ntyevent* ev = ntyreactor_idx(reactor, fd);
    331.  
    332. 	if (ev == NULL) return -1;
    333.  
    334. 	ws_response(ev);
    335.  
    336. 	int len = send(fd, ev->wbuffer, ev->length, 0);
    337. 	if (len > 0) {
    338. 		printf("send[fd=%d], [%d]%s\n", fd, len, ev->wbuffer);
    339.  
    340. 		//发送后，将fd设置为接收事件
    341. 		nty_event_del(reactor->epfd, ev);
    342. 		nty_event_set(ev, fd, recv_cb, reactor);
    343. 		nty_event_add(reactor->epfd, EPOLLIN, ev);
    344. 		
    345. 	} else { //发送失败
    346.  
    347. 		nty_event_del(reactor->epfd, ev);
    348. 		close(ev->fd);
    349.  
    350. 		printf("send[fd=%d] error %s\n", fd, strerror(errno));
    351.  
    352. 	}
    353.  
    354. 	return len;
    355. }
    356.  
    357.  
    358. //客户端接入回调
    359. int accept_cb(int fd, int events, void* arg)
    360. {
    361. 	struct ntyreactor *reactor = (struct ntyreactor*)arg;
    362. 	if (reactor == NULL) return -1;
    363.  
    364. 	struct sockaddr_in client_addr;
    365. 	socklen_t len = sizeof(client_addr);
    366.  
    367. 	int clientfd;
    368.  
    369. 	//客户端接入
    370. 	if ((clientfd = accept(fd, (struct sockaddr*)&client_addr, &len)) == -1) {
    371. 		if (errno != EAGAIN && errno != EINTR) {
    372. 			
    373. 		}
    374. 		printf("accept: %s\n", strerror(errno));
    375. 		return -1;
    376. 	}
    377.  
    378. 	//设置非阻塞fd
    379. 	int flag = 0;
    380. 	if ((flag = fcntl(clientfd, F_SETFL, O_NONBLOCK)) < 0) {
    381. 		printf("%s: fcntl nonblocking failed, %d\n", __func__, MAX_EPOLL_EVENTS);
    382. 		return -1;
    383. 	}
    384.  
    385. 	struct ntyevent *event = ntyreactor_idx(reactor, clientfd);
    386.  
    387. 	if (event == NULL) return -1;
    388.  
    389. 	//将该fd设置为recv
    390. 	nty_event_set(event, clientfd, recv_cb, reactor);
    391. 	nty_event_add(reactor->epfd, EPOLLIN, event);
    392.  
    393. 	printf("new connect [%s:%d], pos[%d]\n", 
    394. 		inet_ntoa(client_addr.sin_addr), ntohs(client_addr.sin_port), clientfd);
    395.  
    396. 	return 0;
    397. }
    398.  
    399. //创建socket监听
    400. int init_sock(short port)
    401. {
    402. 	int fd = socket(AF_INET, SOCK_STREAM, 0);
    403. 	fcntl(fd, F_SETFL, O_NONBLOCK);
    404.  
    405. 	struct sockaddr_in server_addr;
    406. 	memset(&server_addr, 0, sizeof(server_addr));
    407. 	server_addr.sin_family = AF_INET;
    408. 	server_addr.sin_addr.s_addr = htonl(INADDR_ANY);
    409. 	server_addr.sin_port = htons(port);
    410.  
    411. 	bind(fd, (struct sockaddr*)&server_addr, sizeof(server_addr));
    412.  
    413. 	if (listen(fd, 20) < 0) {
    414. 		printf("listen failed : %s\n", strerror(errno));
    415. 		return -1;
    416. 	}
    417.  
    418. 	printf("listen server port : %d\n", port);
    419. 	return fd;
    420. }
    421.  
    422.  
    423. //reactor扩展大小
    424. int ntyreactor_alloc(struct ntyreactor* reactor)
    425. {
    426. 	if(reactor == NULL) return -1;
    427. 	if(reactor->evblks == NULL) return -1;
    428.  
    429. 	struct eventblock* blk = reactor->evblks; //块的头结点
    430.  
    431. 	//找尾节点
    432. 	while(blk->next != NULL){  //找到尾节点
    433. 		blk = blk->next;
    434. 	}
    435.  
    436. 	struct ntyevent* evs = (struct ntyevent*)malloc((MAX_EPOLL_EVENTS) * sizeof(struct ntyevent));
    437. 	if (evs == NULL) {
    438. 		printf("ntyreactor_alloc ntyevent failed\n");
    439. 		return -2;
    440. 	}
    441. 	memset(evs, 0, (MAX_EPOLL_EVENTS) * sizeof(struct ntyevent));
    442.  
    443. 	struct eventblock *block = malloc(sizeof(struct eventblock));
    444. 	if (block == NULL) {
    445. 		printf("ntyreactor_alloc eventblock failed\n");
    446. 		return -3;
    447. 	}
    448. 	//io fd集合连接成块
    449. 	block->events = evs;
    450. 	block->next = NULL;
    451.  
    452. 	//指向新块
    453. 	blk->next = block;
    454. 	reactor->blkcnt ++;
    455.  
    456. 	return 0;
    457. }
    458.  
    459. //根据io fd来找fd结构体
    460. struct ntyevent *ntyreactor_idx(struct ntyreactor *reactor, int sockfd) {
    461. 	if (reactor == NULL) return NULL;
    462. 	if (reactor->evblks == NULL) return NULL;
    463.  
    464. 	int blkidx = sockfd / MAX_EPOLL_EVENTS; //在哪一个块
    465. 	while (blkidx >= reactor->blkcnt) {		//大小不够扩容
    466. 		ntyreactor_alloc(reactor);
    467. 	}
    468.  
    469. 	int i = 0;
    470. 	struct eventblock *blk = reactor->evblks; //头结点块
    471. 	while (i++ != blkidx && blk != NULL) {    //找到所在的块
    472. 		blk = blk->next;
    473. 	}
    474.  
    475. 	return &blk->events[sockfd % MAX_EPOLL_EVENTS]; //返回fd结构体
    476. }
    477.  
    478. //reactor初始化
    479. int ntyreactor_init(struct ntyreactor* reactor)
    480. {
    481. 	if(reactor == NULL) return -1;
    482. 	memset(reactor, 0, sizeof(struct ntyreactor));
    483.  
    484. 	reactor->epfd = epoll_create(1); 
    485. 	if (reactor->epfd <= 0) {
    486. 		printf("create epfd in %s err %s\n", __func__, strerror(errno));
    487. 		return -2;
    488. 	}
    489.  
    490. 	//创建第一个块
    491. 	struct ntyevent* evs = (struct ntyevent*)malloc((MAX_EPOLL_EVENTS) * sizeof(struct ntyevent));
    492. 	if (evs == NULL) {
    493. 		printf("create epfd in %s err %s\n", __func__, strerror(errno));
    494. 		close(reactor->epfd);
    495. 		return -3;
    496. 	}
    497. 	memset(evs, 0, (MAX_EPOLL_EVENTS) * sizeof(struct ntyevent));
    498.  
    499. 	struct eventblock *block = malloc(sizeof(struct eventblock));
    500. 	if (block == NULL) {
    501. 		free(evs);
    502. 		close(reactor->epfd);
    503. 		return -3;
    504. 	}
    505. 	block->events = evs;
    506. 	block->next = NULL;
    507.  
    508. 	reactor->evblks = block;
    509. 	reactor->blkcnt = 1;
    510.  
    511. 	return 0;
    512. }
    513.  
    514. //销毁reactor
    515. int ntyreactor_destory(struct ntyreactor* reactor)
    516. {
    517. 	close(reactor->epfd);
    518.  
    519. 	struct eventblock *blk = reactor->evblks;
    520. 	struct eventblock *blk_next;
    521. 	while (blk != NULL) {
    522. 		blk_next = blk->next;
    523.  
    524. 		free(blk->events);
    525. 		free(blk);
    526. 		
    527. 		blk = blk_next;
    528. 	}
    529.  
    530. 	return 0;
    531. }
    532.  
    533. //初始化接收连接socket
    534. int ntyreactor_addlistener(struct ntyreactor* reactor, int sockfd, NCALLBACK *acceptor){
    535. 	if (reactor == NULL) return -1;
    536. 	if (reactor->evblks == NULL) return -1;
    537.  
    538. 	struct ntyevent* event = ntyreactor_idx(reactor, sockfd);
    539. 	if (event == NULL) return -1;
    540.  
    541. 	nty_event_set(event, sockfd, acceptor, reactor);
    542. 	nty_event_add(reactor->epfd, EPOLLIN, event);
    543.  
    544. 	return 0;
    545. }
    546.  
    547. //reactor事件循环
    548. int ntyreactor_run(struct ntyreactor* reactor)
    549. {
    550. 	if (reactor == NULL) return -1;
    551. 	if (reactor->epfd < 0) return -1;
    552. 	if (reactor->evblks == NULL) return -1;
    553. 	
    554. 	struct epoll_event events[MAX_EPOLL_EVENTS+1];
    555. 	
    556. 	int checkpos = 0, i;
    557.  
    558. 	while(1){
    559. 		int nready = epoll_wait(reactor->epfd, events, MAX_EPOLL_EVENTS, 1000);
    560. 		if (nready < 0) {
    561. 			printf("epoll_wait error, exit\n");
    562. 			continue;
    563. 		}
    564.  
    565. 		for(i = 0;i < nready; i++){
    566. 			struct ntyevent* ev = (struct ntyevent*)events[i].data.ptr; //发生事件的io fd结构体
    567.  
    568. 			if((events[i].events & EPOLLIN) && (ev->events & EPOLLIN)){
    569. 				ev->callback(ev->fd, events[i].events, ev->arg);
    570. 			}
    571. 			if((events[i].events & EPOLLOUT) && (ev->events & EPOLLOUT)){
    572. 				ev->callback(ev->fd, events[i].events, ev->arg);
    573. 			}
    574. 		
    575. 		}
    576.  
    577. 	}
    578.  
    579. }
    580.  
    581. int main(int argc, char *argv[]) {
    582.  
    583. 	struct ntyreactor *reactor = (struct ntyreactor*)malloc(sizeof(struct ntyreactor));
    584. 	ntyreactor_init(reactor);
    585.  
    586. 	//起始的端口号
    587. 	unsigned short port = SERVER_PORT;
    588. 	if (argc == 2) {
    589. 		port = atoi(argv[1]);
    590. 	}
    591.  
    592. 	int i = 0;
    593. 	int sockfds[PORT_COUNT] = {0};
    594.  
    595. 	for (i = 0;i < PORT_COUNT;i ++) {
    596. 		sockfds[i] = init_sock(port+i);
    597. 		ntyreactor_addlistener(reactor, sockfds[i], accept_cb);
    598. 	}
    599.  
    600. 	ntyreactor_run(reactor);
    601.  
    602. 	ntyreactor_destory(reactor);
    603. 	
    604. 	for (i = 0;i < PORT_COUNT;i ++) {
    605. 		close(sockfds[i]);
    606. 	}
    607. 	free(reactor);
    608.  
    609. 	return 0;
    610. }
    611.

    4.运行结果

    总结：

     1. websocket是全双工方式，建立连接后客户端与服务器端是完全平等的，可以互相主动请求。而HTTP长连接基于HTTP，是传统的客户端对服务器发起请求的模式。

    2. HTTP长连接中，每次数据交换除了真正的数据部分外，服务器和客户端还要大量交换HTTP header，信息交换效率很低。Websocket协议通过第一个request建立了TCP连接之后，之后交换的数据都不需要发送 HTTP header就能交换数据。

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  • 原文地址：https://blog.csdn.net/kakaka666/article/details/126318776