add the 'ead' package (emergency access daemon), which can provide remote access to your device, even if the ip and firewall settings are broken
SVN-Revision: 13738
This commit is contained in:
Felix Fietkau
405
package/ead/src/ead-client.c
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405
package/ead/src/ead-client.c
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/*
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* Client for the Emergency Access Daemon
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* Copyright (C) 2008 Felix Fietkau <nbd@openwrt.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2
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* as published by the Free Software Foundation
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <sys/time.h>
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#include <netinet/in.h>
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#include <stdio.h>
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#include <stddef.h>
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#include <stdint.h>
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#include <stdlib.h>
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#include <stdbool.h>
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#include <string.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <t_pwd.h>
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#include <t_read.h>
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#include <t_sha.h>
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#include <t_defines.h>
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#include <t_client.h>
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#include "ead.h"
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#include "ead-crypt.h"
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#include "pw_encrypt_md5.c"
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#define EAD_TIMEOUT 400
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#define EAD_TIMEOUT_LONG 2000
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static char msgbuf[1500];
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static struct ead_msg *msg = (struct ead_msg *) msgbuf;
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static uint16_t nid = 0xffff;
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struct sockaddr_in local, remote;
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static int s = 0;
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static int sockflags;
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static unsigned char *skey = NULL;
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static unsigned char bbuf[MAXPARAMLEN];
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static unsigned char saltbuf[MAXSALTLEN];
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static char *username = NULL;
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static char password[MAXPARAMLEN] = "";
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static char pw_md5[MD5_OUT_BUFSIZE];
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static char pw_salt[MAXSALTLEN];
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static struct t_client *tc = NULL;
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static struct t_num salt = { .data = saltbuf };
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static struct t_num *A, B;
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static struct t_preconf *tcp;
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static int auth_type = EAD_AUTH_DEFAULT;
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static int timeout = EAD_TIMEOUT;
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static void
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set_nonblock(int enable)
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{
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if (enable == !!(sockflags & O_NONBLOCK));
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return;
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sockflags ^= O_NONBLOCK;
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fcntl(s, F_SETFL, sockflags);
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}
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static int
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send_packet(int type, bool (*handler)(void), unsigned int max)
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{
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struct timeval tv;
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fd_set fds;
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int nfds;
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int len;
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int res = 0;
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type = htonl(type);
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set_nonblock(0);
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sendto(s, msgbuf, sizeof(struct ead_msg) + ntohl(msg->len), 0, (struct sockaddr *) &remote, sizeof(remote));
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set_nonblock(1);
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tv.tv_sec = timeout / 1000;
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tv.tv_usec = (timeout % 1000) * 1000;
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FD_ZERO(&fds);
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do {
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FD_SET(s, &fds);
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nfds = select(s + 1, &fds, NULL, NULL, &tv);
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if (nfds <= 0)
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break;
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if (!FD_ISSET(s, &fds))
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break;
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len = read(s, msgbuf, sizeof(msgbuf));
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if (len < 0)
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break;
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if (len < sizeof(struct ead_msg))
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continue;
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if (len < sizeof(struct ead_msg) + ntohl(msg->len))
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continue;
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if (msg->magic != htonl(EAD_MAGIC))
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continue;
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if ((nid != 0xffff) && (ntohs(msg->nid) != nid))
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continue;
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if (msg->type != type)
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continue;
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if (handler())
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res++;
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if ((max > 0) && (res >= max))
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break;
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} while (1);
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return res;
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}
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static void
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prepare_password(void)
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{
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switch(auth_type) {
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case EAD_AUTH_DEFAULT:
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break;
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case EAD_AUTH_MD5:
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md5_crypt(pw_md5, (unsigned char *) password, (unsigned char *) pw_salt);
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strncpy(password, pw_md5, sizeof(password));
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break;
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}
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}
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static bool
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handle_pong(void)
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{
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struct ead_msg_pong *pong = EAD_DATA(msg, pong);
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int len = msg->len - sizeof(struct ead_msg_pong);
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pong->name[len] = 0;
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auth_type = ntohs(pong->auth_type);
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if (nid == 0xffff)
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printf("%04x: %s\n", ntohs(msg->nid), pong->name);
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return true;
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}
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static bool
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handle_prime(void)
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{
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struct ead_msg_salt *sb = EAD_DATA(msg, salt);
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salt.len = sb->len;
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memcpy(salt.data, sb->salt, salt.len);
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if (auth_type == EAD_AUTH_MD5) {
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memcpy(pw_salt, sb->ext_salt, MAXSALTLEN);
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pw_salt[MAXSALTLEN - 1] = 0;
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}
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tcp = t_getpreparam(sb->prime);
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tc = t_clientopen(username, &tcp->modulus, &tcp->generator, &salt);
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if (!tc) {
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fprintf(stderr, "Client open failed\n");
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return false;
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}
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return true;
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}
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static bool
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handle_b(void)
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{
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struct ead_msg_number *num = EAD_DATA(msg, number);
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int len = ntohl(msg->len) - sizeof(struct ead_msg_number);
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B.data = bbuf;
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B.len = len;
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memcpy(bbuf, num->data, len);
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return true;
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}
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static bool
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handle_none(void)
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{
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return true;
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}
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static bool
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handle_done_auth(void)
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{
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struct ead_msg_auth *auth = EAD_DATA(msg, auth);
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if (t_clientverify(tc, auth->data) != 0) {
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fprintf(stderr, "Client auth verify failed\n");
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return false;
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}
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return true;
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}
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static bool
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handle_cmd_data(void)
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{
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struct ead_msg_cmd_data *cmd = EAD_ENC_DATA(msg, cmd_data);
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int datalen = ead_decrypt_message(msg) - sizeof(struct ead_msg_cmd_data);
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if (datalen < 0)
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return false;
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if (datalen > 0) {
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write(1, cmd->data, datalen);
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}
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return !!cmd->done;
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}
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static int
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send_ping(void)
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{
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msg->type = htonl(EAD_TYPE_PING);
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msg->len = 0;
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return send_packet(EAD_TYPE_PONG, handle_pong, (nid == 0xffff ? 0 : 1));
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}
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static int
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send_username(void)
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{
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msg->type = htonl(EAD_TYPE_SET_USERNAME);
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msg->len = htonl(sizeof(struct ead_msg_user));
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strcpy(EAD_DATA(msg, user)->username, username);
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return send_packet(EAD_TYPE_ACK_USERNAME, handle_none, 1);
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}
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static int
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get_prime(void)
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{
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msg->type = htonl(EAD_TYPE_GET_PRIME);
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msg->len = 0;
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return send_packet(EAD_TYPE_PRIME, handle_prime, 1);
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}
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static int
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send_a(void)
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{
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struct ead_msg_number *num = EAD_DATA(msg, number);
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A = t_clientgenexp(tc);
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msg->type = htonl(EAD_TYPE_SEND_A);
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msg->len = htonl(sizeof(struct ead_msg_number) + A->len);
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memcpy(num->data, A->data, A->len);
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return send_packet(EAD_TYPE_SEND_B, handle_b, 1);
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}
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static int
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send_auth(void)
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{
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struct ead_msg_auth *auth = EAD_DATA(msg, auth);
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prepare_password();
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t_clientpasswd(tc, password);
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skey = t_clientgetkey(tc, &B);
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if (!skey)
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return 0;
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ead_set_key(skey);
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msg->type = htonl(EAD_TYPE_SEND_AUTH);
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msg->len = htonl(sizeof(struct ead_msg_auth));
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memcpy(auth->data, t_clientresponse(tc), sizeof(auth->data));
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return send_packet(EAD_TYPE_DONE_AUTH, handle_done_auth, 1);
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}
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static int
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send_command(const char *command)
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{
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struct ead_msg_cmd *cmd = EAD_ENC_DATA(msg, cmd);
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msg->type = htonl(EAD_TYPE_SEND_CMD);
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cmd->type = htons(EAD_CMD_NORMAL);
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cmd->timeout = htons(10);
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strncpy((char *)cmd->data, command, 1024);
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ead_encrypt_message(msg, sizeof(struct ead_msg_cmd) + strlen(command) + 1);
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return send_packet(EAD_TYPE_RESULT_CMD, handle_cmd_data, 1);
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}
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static int
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usage(const char *prog)
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{
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fprintf(stderr, "Usage: %s <node> <username>[:<password>]\n"
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"\n"
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"\n<node>: Node ID (4 digits hex)\n"
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"\n<username>: Username to authenticate with\n"
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"\n"
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"\nPassing no arguments shows a list of active nodes on the network\n"
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"\n", prog);
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return -1;
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}
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int main(int argc, char **argv)
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{
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int val = 1;
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char *st = NULL;
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const char *command = NULL;
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msg->magic = htonl(EAD_MAGIC);
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msg->tid = 0;
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memset(&local, 0, sizeof(local));
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memset(&remote, 0, sizeof(remote));
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remote.sin_family = AF_INET;
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remote.sin_addr.s_addr = 0xffffffff;
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remote.sin_port = htons(EAD_PORT);
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local.sin_family = AF_INET;
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local.sin_addr.s_addr = INADDR_ANY;
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local.sin_port = 0;
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switch(argc) {
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case 4:
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command = argv[3];
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/* fall through */
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case 3:
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username = argv[2];
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st = strchr(username, ':');
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if (st) {
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*st = 0;
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st++;
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strncpy(password, st, sizeof(password));
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password[sizeof(password) - 1] = 0;
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/* hide command line password */
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memset(st, 0, strlen(st));
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}
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/* fall through */
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case 2:
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nid = strtoul(argv[1], &st, 16);
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if (st && st[0] != 0)
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return usage(argv[0]);
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/* fall through */
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case 1:
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break;
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default:
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return usage(argv[0]);
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}
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msg->nid = htons(nid);
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s = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
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if (s < 0) {
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perror("socket");
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return -1;
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}
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setsockopt(s, SOL_SOCKET, SO_BROADCAST, &val, sizeof(val));
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if (bind(s, (struct sockaddr *)&local, sizeof(local)) < 0) {
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perror("bind");
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return -1;
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}
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sockflags = fcntl(s, F_GETFL);
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if (!send_ping()) {
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fprintf(stderr, "No devices found\n");
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return 1;
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}
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if (nid == 0xffff)
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return 0;
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if (!username || !password[0])
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return 0;
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if (!send_username()) {
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fprintf(stderr, "Device did not accept user name\n");
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return 1;
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}
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if (!get_prime()) {
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fprintf(stderr, "Failed to get user password info\n");
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return 1;
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}
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timeout = EAD_TIMEOUT_LONG;
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if (!send_a()) {
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fprintf(stderr, "Failed to send local authentication data\n");
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return 1;
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}
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if (!send_auth()) {
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fprintf(stderr, "Authentication failed\n");
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return 1;
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}
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if (!command) {
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fprintf(stderr, "Authentication succesful\n");
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return 0;
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}
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if (!send_command(command)) {
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fprintf(stderr, "Command failed\n");
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return 1;
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}
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return 0;
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}
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