这里提供一个使用 OpenSSL 库实现 WebSocket 加密通信的示例客户端代码,仅供参考:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <openssl/ssl.h>
#include <openssl/err.h>
#define BUF_SIZE 1024
const char *request_template = "GET /chat HTTP/1.1\r\n"
"Host: %s\r\n"
"Upgrade: websocket\r\n"
"Connection: Upgrade\r\n"
"Sec-WebSocket-Key: dGhlIHNhbXBsZSBub25jZQ==\r\n"
"Sec-WebSocket-Version: 13\r\n"
"\r\n";
int main(int argc, char **argv)
{
if (argc != 3) {
fprintf(stderr, "Usage: %s host port", argv[0]);
exit(1);
}
const char *host = argv[1];
int port = atoi(argv[2]);
SSL_library_init();
SSL_load_error_strings();
SSL_CTX *ctx = SSL_CTX_new(TLS_client_method());
if (!ctx) {
fprintf(stderr, "SSL_CTX_new error");
ERR_print_errors_fp(stderr);
exit(1);
}
int sockfd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if (sockfd == -1) {
perror("socket error");
exit(1);
}
struct sockaddr_in addr;
memset(&addr, 0, sizeof(addr));
addr.sin_family = AF_INET;
addr.sin_addr.s_addr = inet_addr(host);
addr.sin_port = htons(port);
if (connect(sockfd, (struct sockaddr*)&addr, sizeof(addr)) == -1) {
perror("connect error");
exit(1);
}
SSL *ssl = SSL_new(ctx);
if (!ssl) {
fprintf(stderr, "SSL_new error");
ERR_print_errors_fp(stderr);
exit(1);
}
SSL_set_fd(ssl, sockfd);
if (SSL_connect(ssl) != 1) {
fprintf(stderr, "SSL_connect error");
ERR_print_errors_fp(stderr);
exit(1);
}
char request_buf[BUF_SIZE];
snprintf(request_buf, BUF_SIZE, request_template, host);
if (SSL_write(ssl, request_buf, strlen(request_buf)) != strlen(request_buf)) {
fprintf(stderr, "SSL_write error");
ERR_print_errors_fp(stderr);
exit(1);
}
char response_buf[BUF_SIZE];
int nread;
while ((nread = SSL_read(ssl, response_buf, BUF_SIZE - 1)) > 0) {
response_buf[nread] = '\0';
// 这里可以进行 WebSocket 数据帧的解析和处理
printf("%s", response_buf);
memset(response_buf, 0x00, BUF_SIZE);
}
if (nread < 0) {
fprintf(stderr,"SSL_read error\n");
ERR_print_errors_fp(stderr);
exit(1);
}
close(sockfd);
SSL_shutdown(ssl);
SSL_free(ssl);
SSL_CTX_free(ctx);
return 0;
}
需要注意的是,这只是一个示例代码,实际情况下还需要根据自己的需求进行修改和完善。另外,对于 OpenSSL 库的使用,也需要一定的基础知识和实践经验。
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