使用linux上的套接字发出https请求

Question

如何在linux上使用套接字发出http请求？目前,我正在接受

HTTP/1.1 301 Moved Permanently
//etc
Location: https://server.com

这是代码的相关部分(函数太大,无法在此处发布):

 /* Socket file descriptor. */
        int sock;
    struct sockaddr_in sockaddr;
    struct hostent *host; /* Host information. */
    sock = socket(AF_INET, /* IPV4 protocol. */
              SOCK_STREAM, /* TCP socket. */
              0); /* O for socket() function choose the correct protocol based on the socket type. */

    if(sock == INVALID_SOCKET) return SOCK_GENERROR;

    if((host = gethostbyname(server)) == NULL) {
        close(sock);
        return SOCK_HOSTNFOUND;
    }

    /* zero buffer */
    memset(&sockaddr, 0, sizeof(sockaddr));
    sockaddr.sin_family = AF_INET;
    memcpy(&sockaddr.sin_addr,
           host -> h_addr,
           host -> h_length );
    sockaddr.sin_port = htons(port);

    if(connect(sock, (struct sockaddr *)&sockaddr, sizeof(sockaddr)) == INVALID_SOCKET) {
        close(sock);
        return SOCK_FERRCONN;
    }

    if(send(sock, sendbuf, bufsize, 0) == INVALID_SOCKET) {
        close(sock);
        return SOCK_FERRWRITE;
    }


       if((readed = recv(sock, recvbuffer, sizeof(recvbuffer), 0)) <= 0)
    break;

在通话中,server="server.com";和port=80;

我试图尽可能地删除我的onw例程并从此代码中键入以使您更加干净.

Answer 1

https请求看起来就像http请求,但是对客户端和服务器之间的实际通信以及不同的默认端口进行透明加密.好消息是,透明加密允许您像编写常规HTTP客户端一样进行编程.坏消息是加密非常复杂,需要专门的库来为您实现.

一个这样的库是OpenSSL.使用OpenSSL,客户端的最小代码如下所示:

#include <openssl/ssl.h>

// first connect to the remote as usual, but use the port 443 instead of 80

// initialize OpenSSL - do this once and stash ssl_ctx in a global var
SSL_load_error_strings ();
SSL_library_init ();
SSL_CTX *ssl_ctx = SSL_CTX_new (SSLv23_client_method ());

// create an SSL connection and attach it to the socket
SSL *conn = SSL_new(ssl_ctx);
SSL_set_fd(conn, sock);

// perform the SSL/TLS handshake with the server - when on the
// server side, this would use SSL_accept()
int err = SSL_connect(conn);
if (err != 1)
   abort(); // handle error

// now proceed with HTTP traffic, using SSL_read instead of recv() and
// SSL_write instead of send(), and SSL_shutdown/SSL_free before close()

Answer 2

HTTPS就像HTTP，但是封装在加密SSL层中。您将需要使用像OpenSSL这样的库来建立那些HTTPS连接。

OpenSSL将提供替换socket.h的功能，以通过SSL通道连接，读取和写入常规HTTP（或您要使用的任何其他协议），从而使SSL部分的处理对您透明。