2775033198
- 新增 websocket.h / websocket.c：帧解析、编码、握手、连接管理 - server.c: 检测 Upgrade: websocket 请求，执行握手后进入 ws_handle_connection - 支持文本/二进制帧 echo、ping/pong、close 帧 - 使用 OpenSSL SHA1 计算 Sec-WebSocket-Accept - 集成测试：新增 2 项 WebSocket 测试（Python 标准库实现） - 61 项集成测试全部通过，127 项单元测试全部通过
339 lines
10 KiB
C
339 lines
10 KiB
C
/**
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* @file websocket.c
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* @brief WebSocket 协议实现（RFC 6455）
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*
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* 支持握手、帧解析、帧编码、连接管理。
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* 当前为简单 echo 服务器，可扩展为消息路由或广播。
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*/
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#include "websocket.h"
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#include "log.h"
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#include <stdio.h>
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#include <string.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <errno.h>
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#include <openssl/sha.h>
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#include <sys/socket.h>
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/* WebSocket 魔数字符串（GUID） */
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static const char WS_GUID[] = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11";
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/* 基础 64 编码表 */
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static const char BASE64_TABLE[] =
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"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
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/**
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* @brief 简单 Base64 编码（内部使用）
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*
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* @param in 输入数据
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* @param in_len 输入长度
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* @param out 输出缓冲区（至少 4/3 * in_len + 4 字节）
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* @return 输出字符串长度
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*/
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static size_t base64_encode(const uint8_t *in, size_t in_len, char *out) {
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size_t i, j;
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for (i = 0, j = 0; i + 2 < in_len; i += 3, j += 4) {
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uint32_t v = ((uint32_t)in[i] << 16) | ((uint32_t)in[i + 1] << 8) | in[i + 2];
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out[j] = BASE64_TABLE[(v >> 18) & 0x3F];
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out[j + 1] = BASE64_TABLE[(v >> 12) & 0x3F];
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out[j + 2] = BASE64_TABLE[(v >> 6) & 0x3F];
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out[j + 3] = BASE64_TABLE[v & 0x3F];
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}
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if (i < in_len) {
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uint32_t v = (uint32_t)in[i] << 16;
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if (i + 1 < in_len) v |= (uint32_t)in[i + 1] << 8;
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out[j] = BASE64_TABLE[(v >> 18) & 0x3F];
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out[j + 1] = BASE64_TABLE[(v >> 12) & 0x3F];
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out[j + 2] = (i + 1 < in_len) ? BASE64_TABLE[(v >> 6) & 0x3F] : '=';
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out[j + 3] = '=';
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j += 4;
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}
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out[j] = '\0';
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return j;
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}
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/**
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* @brief 生成 WebSocket 握手响应的 Sec-WebSocket-Accept
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*
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* 对 key + GUID 计算 SHA1，然后 Base64 编码。
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*
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* @param key 客户端 Sec-WebSocket-Key
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* @param accept 输出缓冲区（至少 32 字节）
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* @return 0 成功
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*/
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static int ws_compute_accept(const char *key, char *accept) {
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char concat[128];
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size_t key_len = strlen(key);
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if (key_len + sizeof(WS_GUID) >= sizeof(concat)) return -1;
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memcpy(concat, key, key_len);
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memcpy(concat + key_len, WS_GUID, sizeof(WS_GUID) - 1);
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concat[key_len + sizeof(WS_GUID) - 1] = '\0';
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unsigned char digest[SHA_DIGEST_LENGTH];
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SHA1((unsigned char *)concat, key_len + sizeof(WS_GUID) - 1, digest);
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base64_encode(digest, SHA_DIGEST_LENGTH, accept);
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return 0;
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}
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/**
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* @brief 发送完整的 HTTP 响应
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*
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* @param fd 客户端 socket
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* @param buf 数据
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* @param len 长度
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* @return 0 成功，-1 失败
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*/
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static int ws_send_all(int fd, const char *buf, size_t len) {
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size_t sent = 0;
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while (sent < len) {
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ssize_t n = send(fd, buf + sent, len - sent, MSG_NOSIGNAL);
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if (n > 0) {
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sent += (size_t)n;
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} else if (n < 0 && (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR)) {
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continue;
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} else {
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return -1;
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}
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}
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return 0;
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}
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int ws_handshake(int fd, const char *key) {
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char accept[32];
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if (ws_compute_accept(key, accept) != 0) return -1;
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char response[512];
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int n = snprintf(response, sizeof(response),
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"HTTP/1.1 101 Switching Protocols\r\n"
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"Upgrade: websocket\r\n"
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"Connection: Upgrade\r\n"
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"Sec-WebSocket-Accept: %s\r\n"
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"Server: Cocoon/1.0\r\n"
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"\r\n",
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accept);
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if (n < 0 || (size_t)n >= sizeof(response)) return -1;
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return ws_send_all(fd, response, (size_t)n);
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}
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int ws_parse_frame(const uint8_t *data, size_t len, ws_frame_t *frame, size_t *consumed) {
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if (len < 2) return -1; /* 至少需要 2 字节 */
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uint8_t b0 = data[0];
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uint8_t b1 = data[1];
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frame->fin = (b0 >> 7) & 1;
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frame->opcode = b0 & 0x0F;
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frame->masked = (b1 >> 7) & 1;
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uint64_t payload_len = b1 & 0x7F;
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size_t header_len = 2;
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if (payload_len == 126) {
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if (len < 4) return -1;
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payload_len = ((uint64_t)data[2] << 8) | data[3];
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header_len = 4;
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} else if (payload_len == 127) {
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if (len < 10) return -1;
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payload_len = 0;
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for (int i = 0; i < 8; i++) {
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payload_len = (payload_len << 8) | data[2 + i];
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}
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header_len = 10;
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}
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if (frame->masked) {
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if (len < header_len + 4) return -1;
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memcpy(frame->mask_key, data + header_len, 4);
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header_len += 4;
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}
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if (len < header_len + payload_len) return -1;
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frame->payload_len = payload_len;
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if (payload_len > 0) {
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frame->payload = (uint8_t *)malloc(payload_len + 1);
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if (!frame->payload) return -2;
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memcpy(frame->payload, data + header_len, payload_len);
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if (frame->masked) {
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for (uint64_t i = 0; i < payload_len; i++) {
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frame->payload[i] ^= frame->mask_key[i % 4];
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}
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}
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frame->payload[payload_len] = '\0';
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} else {
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frame->payload = NULL;
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}
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*consumed = header_len + payload_len;
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return 0;
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}
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void ws_frame_free(ws_frame_t *frame) {
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if (frame && frame->payload) {
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free(frame->payload);
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frame->payload = NULL;
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}
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}
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int ws_send_frame(int fd, uint8_t opcode, const uint8_t *payload, size_t len) {
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uint8_t header[14];
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size_t header_len = 0;
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header[0] = 0x80 | (opcode & 0x0F); /* FIN=1, opcode */
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if (len <= 125) {
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header[1] = (uint8_t)len;
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header_len = 2;
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} else if (len <= 65535) {
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header[1] = 126;
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header[2] = (uint8_t)(len >> 8);
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header[3] = (uint8_t)(len & 0xFF);
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header_len = 4;
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} else {
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header[1] = 127;
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for (int i = 0; i < 8; i++) {
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header[2 + i] = (uint8_t)(len >> (56 - i * 8));
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}
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header_len = 10;
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}
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/* 服务器发送不掩码 */
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if (ws_send_all(fd, (char *)header, header_len) != 0) return -1;
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if (len > 0 && ws_send_all(fd, (char *)payload, len) != 0) return -1;
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return 0;
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}
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int ws_send_text(int fd, const char *text) {
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return ws_send_frame(fd, WS_OP_TEXT, (const uint8_t *)text, strlen(text));
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}
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int ws_send_close(int fd, uint16_t code, const char *reason) {
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uint8_t payload[128];
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size_t len = 0;
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if (code != 0) {
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payload[0] = (uint8_t)(code >> 8);
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payload[1] = (uint8_t)(code & 0xFF);
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len = 2;
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if (reason) {
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size_t rlen = strlen(reason);
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if (rlen > sizeof(payload) - 3) rlen = sizeof(payload) - 3;
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memcpy(payload + 2, reason, rlen);
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len += rlen;
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}
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}
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return ws_send_frame(fd, WS_OP_CLOSE, payload, len);
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}
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int ws_send_ping(int fd) {
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return ws_send_frame(fd, WS_OP_PING, NULL, 0);
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}
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int ws_send_pong(int fd, const uint8_t *payload, size_t len) {
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return ws_send_frame(fd, WS_OP_PONG, payload, len);
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}
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/**
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* @brief 从连接读取数据（简单阻塞读取）
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*/
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static ssize_t ws_read_data(int fd, uint8_t *buf, size_t max_len) {
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ssize_t n = recv(fd, buf, max_len, 0);
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return n;
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}
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void ws_handle_connection(int fd, uint32_t timeout_ms) {
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(void)timeout_ms; /* TODO: 超时处理 */
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uint8_t buf[8192];
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size_t buf_len = 0;
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bool closed = false;
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log_info("WebSocket 连接建立 fd=%d", fd);
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while (!closed) {
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ssize_t n = ws_read_data(fd, buf + buf_len, sizeof(buf) - buf_len);
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if (n <= 0) {
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if (n < 0 && (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR)) {
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continue;
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}
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log_debug("WebSocket fd=%d 读取结束或错误", fd);
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break;
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}
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buf_len += (size_t)n;
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/* 解析帧 */
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size_t parsed = 0;
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while (parsed < buf_len) {
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ws_frame_t frame = {0};
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size_t consumed = 0;
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int ret = ws_parse_frame(buf + parsed, buf_len - parsed, &frame, &consumed);
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if (ret == -1) {
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break; /* 数据不完整，等待更多 */
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}
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if (ret == -2) {
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log_warn("WebSocket fd=%d 收到畸形帧", fd);
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ws_send_close(fd, 1002, "Protocol error");
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closed = true;
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break;
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}
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parsed += consumed;
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switch (frame.opcode) {
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case WS_OP_TEXT:
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log_debug("WebSocket fd=%d 收到文本: %s", fd,
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frame.payload ? (char *)frame.payload : "(empty)");
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if (frame.fin) {
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ws_send_text(fd, frame.payload ? (char *)frame.payload : "");
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}
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break;
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case WS_OP_BINARY:
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log_debug("WebSocket fd=%d 收到二进制 %llu 字节", fd,
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(unsigned long long)frame.payload_len);
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/* 简单 echo 回二进制 */
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ws_send_frame(fd, WS_OP_BINARY, frame.payload, frame.payload_len);
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break;
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case WS_OP_CLOSE:
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log_info("WebSocket fd=%d 收到关闭帧", fd);
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ws_send_close(fd, 1000, NULL);
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closed = true;
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break;
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case WS_OP_PING:
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log_debug("WebSocket fd=%d 收到 Ping", fd);
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ws_send_pong(fd, frame.payload, frame.payload_len);
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break;
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case WS_OP_PONG:
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log_debug("WebSocket fd=%d 收到 Pong", fd);
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break;
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case WS_OP_CONT:
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log_debug("WebSocket fd=%d 收到继续帧", fd);
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break;
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default:
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log_warn("WebSocket fd=%d 未知操作码 %d", fd, frame.opcode);
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break;
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}
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ws_frame_free(&frame);
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}
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/* 移动剩余数据到缓冲区开头 */
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if (parsed > 0 && parsed < buf_len) {
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memmove(buf, buf + parsed, buf_len - parsed);
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buf_len -= parsed;
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} else if (parsed == buf_len) {
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buf_len = 0;
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}
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}
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log_info("WebSocket 连接关闭 fd=%d", fd);
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}
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