https_proxy.c

#include "https_proxy.h"

// 解析 CONNECT 请求，提取 target_host 和 target_port
// 请求格式：CONNECT example.com:443 HTTP/1.1\r\n\r\n
int https_parse_connect(const char* req_buf, int req_len, char* target_host, int host_len, uint16_t* target_port) {
    char method[16], path[256], version[16];
    if (sscanf(req_buf, "%s %s %s", method, path, version) != 3) {
        return -1;
    }

    // 校验是否为 CONNECT 方法
    if (strcmp(method, "CONNECT") != 0) {
        return -1;
    }

    // 分割 path 中的 host 和 port（默认 443）
    char* colon_pos = strchr(path, ':');
    if (colon_pos) {
        *colon_pos = '\0';
        snprintf(target_host, host_len, "%s", path);
        *target_port = atoi(colon_pos + 1);
    } else {
        snprintf(target_host, host_len, "%s", path);
        *target_port = 443;
    }

    return 0;
}

// 向客户端返回 200 Connection Established 响应
int https_send_200(SOCKET_T client_sock) {
    const char* resp = "HTTP/1.1 200 Connection Established\r\n\r\n";
    return send(client_sock, resp, strlen(resp), 0);
}

// 解析普通 HTTP 请求（提取 Host 头中的目标地址）
int http_parse_request(const char* req_buf, int req_len, char* target_host, int host_len, uint16_t* target_port) {
    // 1. 先提取 Host 头（HTTP 请求的核心，格式：Host: www.baidu.com:80）
    const char* host_header = strstr(req_buf, "Host: ");
    if (host_header == NULL) {
        return -1;
    }
    host_header += 6; // 跳过 "Host: " 字符串

    // 2. 提取 Host 内容（直到 \r 或 \n 结束）
    char host_buf[256] = {0};
    int i = 0;
    while (host_header[i] != '\r' && host_header[i] != '\n' && host_header[i] != '\0' && i < sizeof(host_buf)-1) {
        host_buf[i] = host_header[i];
        i++;
    }

    // 3. 分割 host 和 port（HTTP 默认端口 80）
    char* colon_pos = strchr(host_buf, ':');
    if (colon_pos) {
        *colon_pos = '\0';
        snprintf(target_host, host_len, "%s", host_buf);
        *target_port = atoi(colon_pos + 1);
    } else {
        snprintf(target_host, host_len, "%s", host_buf);
        *target_port = 80; // HTTP 默认端口
    }

    return 0;
}