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/*
* ident.c - TCP/IP ident protocol query
*
* Copyright (C) 1999 Etienne Bernard
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <signal.h>
#include <sys/time.h>
#include <sys/types.h>
#include <unistd.h>
#include <fcntl.h>
#include <netdb.h>
#include <string.h>
#include <stdio.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <errno.h>
#include <setjmp.h>
#include "defines.h"
#include "ident.h"
static jmp_buf ident_alarm;
void timeout_alarm(int sig) {
siglongjmp(ident_alarm, 1);
}
char * get_ident_info(unsigned short int local_port, unsigned short int remote_port, __u32 local_addr, __u32 remote_addr) {
unsigned int remote, local;
int s, i, j;
char *c;
struct sockaddr_in sin;
char buffer[LINE], user[IDENT_LENGTH];
signal(SIGALRM, timeout_alarm);
s = socket(AF_INET, SOCK_STREAM, 0);
if (s < 0)
goto unknown;
if (sigsetjmp(ident_alarm, 1) != 0)
goto unknown;
alarm(IDENT_TIMEOUT);
sin.sin_family = AF_INET;
sin.sin_addr.s_addr = local_addr;
sin.sin_port = INADDR_ANY;
if (bind(s, (struct sockaddr *)&sin, sizeof(sin)) < 0)
goto unknown;
sin.sin_family = AF_INET;
sin.sin_addr.s_addr = remote_addr;
sin.sin_port = IDENT_PORT;
if (connect(s, (struct sockaddr *)&sin, sizeof(sin)) < 0)
goto unknown;
sprintf(buffer, "%u,%u\r\n", ntohs(remote_port), ntohs(local_port));
/* send query */
i = 0;
while (i < strlen(buffer)) {
j = write(s, buffer + i, strlen(buffer+i));
if (j < 0 && errno != EINTR)
goto unknown;
else if (j > 0)
i+=j;
}
/* read response */
i = 0;
*buffer = '\0';
while ((c=strchr(buffer, '\n')) == NULL && i < sizeof(buffer) - 1) {
j = read(s, buffer + i, sizeof(buffer) - 1 - i);
if (j==0 || (j < 0 && errno != EINTR))
goto unknown;
else if (j > 0)
i+=j;
}
if (sscanf(buffer, "%u , %u : USERID :%*[^:]:%64s", &remote, &local, user) != 3 ||
ntohs(remote_port) != remote ||
ntohs(local_port) != local)
goto unknown;
if ((c = strchr(user, '\r')))
*c = '\0';
alarm(0);
close(s);
return strdup(user);
unknown:
if (s > 0)
close(s);
alarm(0);
return strdup(IDENT_UNKNOWN);
}
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