C调用OPENSSL做REST服务客户端的例子

//SSL-Client.c

#include <stdio.h>

#include <errno.h>

#include <unistd.h>

#include <malloc.h>

#include <string.h>

#include <sys/socket.h>

#include <resolv.h>

#include <netdb.h>

#include <openssl/ssl.h>

#include <openssl/err.h>

 

#define FAIL    -1

 

int OpenConnection(const char *hostname, int port)

{   int sd;

    struct hostent *host;

    struct sockaddr_in addr;

 

    if ( (host = gethostbyname(hostname)) == NULL )

    {

        perror(hostname);

        abort();

    }

    sd = socket(PF_INET, SOCK_STREAM, 0);

    bzero(&addr, sizeof(addr));

    addr.sin_family = AF_INET;

    addr.sin_port = htons(port);

    addr.sin_addr.s_addr = *(long*)(host->h_addr);

    if ( connect(sd, (struct sockaddr*)&addr, sizeof(addr)) != 0 )

    {

        close(sd);

        perror(hostname);

        abort();

    }

    return sd;

}

 

SSL_CTX* InitCTX(void)

{   SSL_METHOD *method;

    SSL_CTX *ctx;

 

    OpenSSL_add_all_algorithms();  /* Load cryptos, et.al. */

    SSL_load_error_strings();   /* Bring in and register error messages */

    method = SSLv3_client_method();  /* Create new client-method instance */

    ctx = SSL_CTX_new(method);   /* Create new context */

    if ( ctx == NULL )

    {

        ERR_print_errors_fp(stderr);

        abort();

    }

    return ctx;

}

 

void ShowCerts(SSL* ssl)

{   X509 *cert;

    char *line;

 

    cert = SSL_get_peer_certificate(ssl); /* get the server's certificate */

    if ( cert != NULL )

    {

        printf("Server certificates: ");

        line = X509_NAME_oneline(X509_get_subject_name(cert), 0, 0);

        printf("Subject: %s ", line);

        free(line);       /* free the malloc'ed string */

        line = X509_NAME_oneline(X509_get_issuer_name(cert), 0, 0);

        printf("Issuer: %s ", line);

        free(line);       /* free the malloc'ed string */

        X509_free(cert);     /* free the malloc'ed certificate copy */

    }

    else

        printf("No certificates. ");

}

 

int main(int count, char *strings[])

{   SSL_CTX *ctx;

    int server;

    SSL *ssl;

    char buf[1024];

    int bytes;

    char *hostname, *portnum;

 

    if ( count != 3 )

    {

        printf("usage: %s <hostname> <portnum> ", strings[0]);

        exit(0);

    }

    SSL_library_init();

    hostname=strings[1];

    portnum=strings[2];

 

    ctx = InitCTX();

    server = OpenConnection(hostname, atoi(portnum));

    ssl = SSL_new(ctx);      /* create new SSL connection state */

    SSL_set_fd(ssl, server);    /* attach the socket descriptor */

    if ( SSL_connect(ssl) == FAIL )   /* perform the connection */

        ERR_print_errors_fp(stderr);

    else

    {   char *msg = "Hello???";

 

        printf("Connected with %s encryption ", SSL_get_cipher(ssl));

        ShowCerts(ssl);        /* get any certs */

        SSL_write(ssl, msg, strlen(msg));   /* encrypt & send message */

        bytes = SSL_read(ssl, buf, sizeof(buf)); /* get reply & decrypt */

        buf[bytes] = 0;

        printf("Received: "%s" ", buf);

        SSL_free(ssl);        /* release connection state */

    }

    close(server);         /* close socket */

    SSL_CTX_free(ctx);        /* release context */

    return 0;

}

 

PS：个人觉得这个可能会中文会乱码