Openssh vs ssh2

[may nothing]

Hi all,

I finally finished my little sftp-client taht uses the libssh2 library and made 
some tests.

I downloaded a 260MB testfile from a remote machine via openssh's sftp clienet 
and my own binary. The linux "time" command measured the time spend.
For openssh's sftp client: 3:48 
For libssh2 sftp client: 5:56

(For curl sftp client: 12:44)

Question: Why is the libssh2 sftp so much slower (or is it an issue of my code) 
that the openssh one ?
What can be done to increase the transfer speed ?

Please find attached my sourcecode.

cu
may


#include <libssh2.h>
#include <libssh2_sftp.h>
 

#include <sys/socket.h>
#include <netinet/in.h>
#include <unistd.h>
#include <arpa/inet.h>
 
#include <sys/types.h>
#include <fcntl.h>
#include <errno.h>
#include <stdio.h>
#include <ctype.h>
 
int main(int argc, char *argv[])
{
    unsigned long hostaddr;
    int sock, i, rc;
    struct sockaddr_in sin;
    const char *fingerprint;
    LIBSSH2_SESSION *session;
    FILE *local_file_handle;
    LIBSSH2_SFTP *sftp_session;
    LIBSSH2_SFTP_HANDLE *sftp_handle;

    const char *username="bla";
    const char *password="blub";
    const char *local_file="core-n";
    const char *remote_file="/tmp/core-n";

 
        if (argc > 1) 
        {
           hostaddr = inet_addr(argv[1]);
        } 
        else 
        {
           hostaddr = htonl(0xC0A80001); // hostaddress as hex value without 
dot separation
        }
 
        if(argc > 2) 
        {
           username = argv[2];
        }
        if(argc > 3) 
        {
           password = argv[3];
        }
        if(argc > 4) 
        {
           local_file = argv[4];
        }
        if(argc > 5) 
        {
           remote_file = argv[5];
        }       
 
    rc = libssh2_init (0);

    if (rc != 0) 
    {
        fprintf (stderr, "libssh2 initialization failed (%d)\n", rc);
        return 1;
    }
 
    local_file_handle = fopen(local_file, "wb");
    if (!local_file_handle) 
    {
        printf("Can't create local file %s\n", local_file);
        return -1;
    }
 
    /*
     * The application code is responsible for creating the socket
     * and establishing the connection
     */ 
    sock = socket(AF_INET, SOCK_STREAM, 0);
 
    sin.sin_family = AF_INET;
    sin.sin_port = htons(22);
    sin.sin_addr.s_addr = hostaddr;
    if (connect(sock, (struct sockaddr*)(&sin), sizeof(struct sockaddr_in)) != 
0) 
        {
           fprintf(stderr, "failed to connect!\n");
           return -1;
        }
 
    session = libssh2_session_init();

    if(!session)
        return -1;

    // libssh2_trace(session, LIBSSH2_TRACE_ERROR | LIBSSH2_TRACE_AUTH | 
LIBSSH2_TRACE_SFTP); //enable to trace

    libssh2_session_set_blocking(session, 1);

    rc = libssh2_session_startup(session, sock);

    if(rc != 0) 
    {
        fprintf(stderr, "Failure establishing SSH session: %d\n", rc);
        return -1;
    }
 
    fingerprint = libssh2_hostkey_hash(session, LIBSSH2_HOSTKEY_HASH_SHA1);

    printf("Fingerprint: ");
    for(i = 0; i < 20; i++) 
    {
        printf("%02X ", (unsigned char)fingerprint[i]);
    }
    printf("\n");

    rc = libssh2_userauth_password_ex(session, username, strlen(username), 
password, strlen(password), NULL);
     
    if (rc != 0) 
    {
          fprintf(stderr, "Authentication by password failed\n");
          printf("Error: %d\n", rc);
          goto shutdown;
    }
 
    fprintf(stderr, "libssh2_sftp_init()!\n");

    sftp_session = libssh2_sftp_init(session);
 
    if (!sftp_session) 
    {
        fprintf(stderr, "Unable to init SFTP session\n");
        goto shutdown;
    }
 
    fprintf(stderr, "libssh2_sftp_open()!\n");

    /* Request a file via SFTP */ 
    sftp_handle = libssh2_sftp_open(sftp_session, remote_file 
,LIBSSH2_FXF_READ,0);
 
    if (!sftp_handle) 
    {
        fprintf(stderr, "Unable to open file with SFTP\n");
        goto shutdown;
    }
    fprintf(stderr, "libssh2_sftp_read() ... receiveing data!\n");

    do {
        char mem[32768];
 
        rc = libssh2_sftp_read(sftp_handle, mem, sizeof(mem));

        if (rc > 0) 
          {
            fwrite(mem,rc,1,local_file_handle);
        } 
          else 
          {
          break;
        }
    } while (1);
 
    libssh2_sftp_close(sftp_handle);
    fprintf(stderr, "libssh2_sftp_close()!\n");

    libssh2_sftp_shutdown(sftp_session);

 
  shutdown:
 
    libssh2_session_disconnect(session, "Shutdown");

    libssh2_session_free(session);


    close(sock);

    fprintf(stderr, "done\n");
 
    libssh2_exit();

 
    return 0;
}

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