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/*
*
* Copyright 1989 by the Massachusetts Institute of Technology.
*
* For copying and distribution information, please see the file
* <mit-copyright.h>.
*
* Simple UDP-based sample client program. For demonstration.
* This program performs no useful function.
*/
#include "sample.h"
RCSID("$Id: simple_client.c,v 1.13 1998/06/09 19:24:39 joda Exp $");
#define MSG "hi, Jennifer!" /* message text */
static int
talkto(char *hostname, char *service, int port)
{
int flags = 0; /* flags for sendto() */
long len;
u_long cksum = 0L; /* cksum not used */
char c_realm[REALM_SZ]; /* local Kerberos realm */
char *s_realm; /* server's Kerberos realm */
KTEXT_ST k; /* Kerberos data */
KTEXT ktxt = &k;
int sock, i;
struct hostent *host;
struct sockaddr_in s_sock; /* server address */
char myhostname[MaxHostNameLen]; /* local hostname */
/* for krb_mk_safe/priv */
struct sockaddr_in c_sock; /* client address */
CREDENTIALS c; /* ticket & session key */
CREDENTIALS *cred = &c;
/* for krb_mk_priv */
des_key_schedule sched; /* session key schedule */
/* Look up server host */
if ((host = gethostbyname(hostname)) == NULL) {
fprintf(stderr, "%s: unknown host \n", hostname);
return 1;
}
/* Set server's address */
memset(&s_sock, 0, sizeof(s_sock));
memcpy(&s_sock.sin_addr, host->h_addr, sizeof(s_sock.sin_addr));
s_sock.sin_family = AF_INET;
if (port)
s_sock.sin_port = port;
else
s_sock.sin_port = k_getportbyname (service, "tcp", htons(SAMPLE_PORT));
if (gethostname(myhostname, sizeof(myhostname)) < 0) {
warn("gethostname");
return 1;
}
if ((host = gethostbyname(myhostname)) == NULL) {
fprintf(stderr, "%s: unknown host\n", myhostname);
return 1;
}
/* Open a socket */
if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
warn("socket SOCK_DGRAM");
return 1;
}
memset(&c_sock, 0, sizeof(c_sock));
memcpy(&c_sock.sin_addr, host->h_addr, sizeof(c_sock.sin_addr));
c_sock.sin_family = AF_INET;
/* Bind it to set the address; kernel will fill in port # */
if (bind(sock, (struct sockaddr *)&c_sock, sizeof(c_sock)) < 0) {
warn("bind");
return 1;
}
/* Get local realm, not needed, just an example */
if ((i = krb_get_lrealm(c_realm, 1)) != KSUCCESS) {
fprintf(stderr, "can't find local Kerberos realm\n");
return 1;
}
printf("Local Kerberos realm is %s\n", c_realm);
/* Get Kerberos realm of host */
s_realm = krb_realmofhost(hostname);
/* PREPARE KRB_MK_REQ MESSAGE */
/* Get credentials for server, create krb_mk_req message */
if ((i = krb_mk_req(ktxt, service, hostname, s_realm, cksum))
!= KSUCCESS) {
fprintf(stderr, "%s\n", krb_get_err_text(i));
return 1;
}
printf("Got credentials for %s.\n", service);
/* Send authentication info to server */
i = sendto(sock, (char *)ktxt->dat, ktxt->length, flags,
(struct sockaddr *)&s_sock, sizeof(s_sock));
if (i < 0)
warn("sending datagram message");
printf("Sent authentication data: %d bytes\n", i);
/* PREPARE KRB_MK_SAFE MESSAGE */
/* Get my address */
memset(&c_sock, 0, sizeof(c_sock));
i = sizeof(c_sock);
if (getsockname(sock, (struct sockaddr *)&c_sock, &i) < 0) {
warn("getsockname");
return 1;
}
/* Get session key */
i = krb_get_cred(service, hostname, s_realm, cred);
if (i != KSUCCESS)
return 1;
/* Make the safe message */
len = krb_mk_safe(MSG, ktxt->dat, strlen(MSG)+1,
&cred->session, &c_sock, &s_sock);
/* Send it */
i = sendto(sock, (char *)ktxt->dat, (int) len, flags,
(struct sockaddr *)&s_sock, sizeof(s_sock));
if (i < 0)
warn("sending safe message");
printf("Sent checksummed message: %d bytes\n", i);
/* PREPARE KRB_MK_PRIV MESSAGE */
#ifdef NOENCRYPTION
memset(sched, 0, sizeof(sched));
#else
/* Get key schedule for session key */
des_key_sched(&cred->session, sched);
#endif
/* Make the encrypted message */
len = krb_mk_priv(MSG, ktxt->dat, strlen(MSG)+1,
sched, &cred->session, &c_sock, &s_sock);
/* Send it */
i = sendto(sock, (char *)ktxt->dat, (int) len, flags,
(struct sockaddr *)&s_sock, sizeof(s_sock));
if (i < 0)
warn("sending encrypted message");
printf("Sent encrypted message: %d bytes\n", i);
return 0;
}
static void
usage (void)
{
fprintf (stderr, "Usage: %s [-s service] [-p port] hostname\n",
__progname);
exit (1);
}
int
main(int argc, char **argv)
{
int ret = 0;
int port = 0;
char service[SNAME_SZ];
struct servent *serv;
int c;
set_progname (argv[0]);
strcpy_truncate (service, SAMPLE_SERVICE, sizeof(service));
while ((c = getopt(argc, argv, "s:p:")) != EOF)
switch(c) {
case 's' :
strcpy_truncate (service, optarg, sizeof(service));
break;
case 'p' :
serv = getservbyname (optarg, "tcp");
if (serv)
port = serv->s_port;
else
port = htons(atoi(optarg));
break;
case '?' :
default :
usage();
}
argc -= optind;
argv += optind;
while (argc-- > 0)
ret &= talkto (*argv++, service, port);
return ret;
}
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