client_common.c

   1 /*
   2  * Copyright (C) 1997-2007 Andre Noll <maan@systemlinux.org>
   3  *
   4  *     This program is free software; you can redistribute it and/or modify
   5  *     it under the terms of the GNU General Public License as published by
   6  *     the Free Software Foundation; either version 2 of the License, or
   7  *     (at your option) any later version.
   8  *
   9  *     This program is distributed in the hope that it will be useful,
  10  *     but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  *     GNU General Public License for more details.
  13  *
  14  *     You should have received a copy of the GNU General Public License
  15  *     along with this program; if not, write to the Free Software
  16  *     Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111, USA.
  17  */
  18
  19 /** \file client_common.c common functions of para_client and para_audiod */
  20
  21 #include "para.h"
  22 #include "list.h"
  23 #include "sched.h"
  24 #include "client.cmdline.h"
  25 #include "crypt.h"
  26 #include "rc4.h"
  27 #include "net.h"
  28 #include "fd.h"
  29 #include "string.h"
  30 #include "client.cmdline.h"
  31 #include "client.h"
  32 #include "error.h"
  33
  34 /*
  35  * rc4 encrypt data before sending
  36  *
  37  * \param len the number of bytes to encrypt
  38  * \param indata pointer to the input data of length \a len to be encrypted
  39  * \param outdata pointer that holds the encrypted data after return
  40  * \param private_data pointer to the private client data containing
  41  * the rc4 key
  42  * */
  43 static void rc4_send(unsigned long len, const unsigned char *indata,
  44                 unsigned char *outdata, void *private_data)
  45 {
  46         struct private_client_data *pcd = private_data;
  47         RC4(&pcd->rc4_send_key, len, indata, outdata);
  48 }
  49
  50 /*
  51  * rc4 decrypt received data
  52  *
  53  * \param len the number of bytes to decrypt
  54  * \param indata pointer to the input data of length \a len
  55  * \param outdata pointer that holds the decrypted data after return
  56  * \param private_data pointer to the private client data containing
  57  * the rc4 key
  58  * */
  59 static void rc4_recv(unsigned long len, const unsigned char *indata,
  60                 unsigned char *outdata, void *private_data)
  61 {
  62         struct private_client_data *pcd = private_data;
  63         RC4(&pcd->rc4_recv_key, len, indata, outdata);
  64 }
  65
  66 /**
  67  * close the connection to para_server and free all resources
  68  *
  69  * \param pcd pointer to the client data
  70  *
  71  * \sa client_open.
  72  * */
  73 void client_close(struct private_client_data *pcd)
  74 {
  75         if (!pcd)
  76                 return;
  77         if (pcd->fd >= 0) {
  78                 disable_crypt(pcd->fd);
  79                 close(pcd->fd);
  80         }
  81         free(pcd->user);
  82         free(pcd->config_file);
  83         free(pcd->key_file);
  84         client_cmdline_parser_free(&pcd->conf);
  85         free(pcd);
  86 }
  87
  88 static int client_connect(struct private_client_data *pcd)
  89 {
  90         int ret;
  91         struct hostent *he;
  92         struct sockaddr_in their_addr;
  93
  94         pcd->fd = -1;
  95         ret = get_host_info(pcd->conf.hostname_arg, &he);
  96         if (ret < 0)
  97                 return ret;
  98         /* get new socket */
  99         ret = get_socket();
 100         if (ret < 0)
 101                 return ret;
 102         pcd->fd = ret;
 103         /* init their_addr */
 104         init_sockaddr(&their_addr, pcd->conf.server_port_arg, he);
 105         ret = para_connect(pcd->fd, &their_addr);
 106         if (ret < 0)
 107                 goto err_out;
 108         pcd->status = CL_CONNECTED;
 109         ret = mark_fd_nonblock(pcd->fd);
 110         if (ret < 0)
 111                 goto err_out;
 112         pcd->task.pre_select = client_pre_select;
 113         pcd->task.post_select = client_post_select;
 114         pcd->task.private_data = pcd;
 115         sprintf(pcd->task.status, "client");
 116         register_task(&pcd->task);
 117         return 1;
 118 err_out:
 119         close(pcd->fd);
 120         pcd->fd = -1;
 121         return ret;
 122 }
 123
 124 /**
 125  * open connection to para_server
 126  *
 127  * \param argc usual argument count
 128  * \param argv usual argument vector
 129  * \param pcd_ptr points to dynamically allocated and initialized private client data
 130  * upon successful return
 131  *
 132  * Check the command line options given by \a argc and argv, set default values
 133  * for user name and rsa key file, read further option from the config file.
 134  * Finally, establish a connection to para_server.
 135  *
 136  * \return Positive on success, negative on errors.
 137  */
 138 int client_open(int argc, char *argv[], struct private_client_data **pcd_ptr)
 139 {
 140         char *home = para_homedir();
 141         struct stat statbuf;
 142         int ret;
 143         struct private_client_data *pcd =
 144                 para_calloc(sizeof(struct private_client_data));
 145
 146         *pcd_ptr = pcd;
 147         pcd->fd = -1;
 148         ret = client_cmdline_parser(argc, argv, &pcd->conf);
 149         HANDLE_VERSION_FLAG("client", pcd->conf);
 150         ret = -E_CLIENT_SYNTAX;
 151         if (!pcd->conf.inputs_num)
 152                 goto out;
 153         pcd->user = pcd->conf.user_given?
 154                 para_strdup(pcd->conf.user_arg) : para_logname();
 155
 156         pcd->key_file = pcd->conf.key_file_given?
 157                 para_strdup(pcd->conf.key_file_arg) :
 158                 make_message("%s/.paraslash/key.%s", home, pcd->user);
 159
 160         pcd->config_file = pcd->conf.config_file_given?
 161                 para_strdup(pcd->conf.config_file_arg) :
 162                 make_message("%s/.paraslash/client.conf", home);
 163         ret = stat(pcd->config_file, &statbuf);
 164         if (ret && pcd->conf.config_file_given) {
 165                 ret = -E_NO_CONFIG;
 166                 goto out;
 167         }
 168         if (!ret)
 169                 client_cmdline_parser_configfile(pcd->config_file,
 170                         &pcd->conf, 0, 0, 0);
 171         ret = 1;
 172         PARA_INFO_LOG("loglevel: %d\n", pcd->conf.loglevel_arg);
 173         PARA_INFO_LOG("config_file: %s\n", pcd->config_file);
 174         PARA_INFO_LOG("key_file: %s\n", pcd->key_file);
 175         PARA_NOTICE_LOG("connecting %s:%d\n", pcd->conf.hostname_arg,
 176                 pcd->conf.server_port_arg);
 177         ret = client_connect(pcd);
 178 out:
 179         free(home);
 180         if (ret < 0) {
 181                 PARA_ERROR_LOG("%s\n", PARA_STRERROR(-ret));
 182                 client_close(pcd);
 183                 *pcd_ptr = NULL;
 184         }
 185         return ret;
 186 }
 187
 188 /**
 189  * the preselect hook for server commands
 190  *
 191  * \param s pointer to the scheduler
 192  * \param t pointer to the task struct for this command
 193  *
 194  * The task pointer must contain a pointer to the initialized client data
 195  * structure as it is returned by client_open().
 196  *
 197  * This function checks the state of the connection and adds the file descriptor
 198  * of the connection to the read or write fd set of \a s accordingly.
 199  *
 200  * \sa register_task() client_open(), struct sched, struct task
 201  */
 202 void client_pre_select(struct sched *s, struct task *t)
 203 {
 204         struct private_client_data *pcd = t->private_data;
 205
 206         t->ret = 1;
 207         pcd->check_r = 0;
 208         pcd->check_w = 0;
 209         if (pcd->fd < 0)
 210                 return;
 211         switch (pcd->status) {
 212         case CL_CONNECTED:
 213         case CL_SENT_AUTH:
 214         case CL_SENT_CH_RESPONSE:
 215         case CL_SENT_COMMAND:
 216                 para_fd_set(pcd->fd, &s->rfds, &s->max_fileno);
 217                 pcd->check_r = 1;
 218                 return;
 219
 220         case CL_RECEIVED_WELCOME:
 221         case CL_RECEIVED_CHALLENGE:
 222         case CL_RECEIVED_PROCEED:
 223                 para_fd_set(pcd->fd, &s->wfds, &s->max_fileno);
 224                 pcd->check_w = 1;
 225                 return;
 226
 227         case CL_RECEIVING:
 228                 if (pcd->loaded < CLIENT_BUFSIZE - 1) {
 229                         para_fd_set(pcd->fd, &s->rfds, &s->max_fileno);
 230                         pcd->check_r = 1;
 231                 }
 232                 return;
 233         case CL_SENDING:
 234                 if (*pcd->in_loaded) {
 235                         PARA_INFO_LOG("loaded: %zd\n", *pcd->in_loaded);
 236                         para_fd_set(pcd->fd, &s->wfds, &s->max_fileno);
 237                         pcd->check_w = 1;
 238                 } else {
 239                         if (*pcd->in_eof) {
 240                                 t->ret = -E_INPUT_EOF;
 241                                 s->timeout.tv_sec = 0;
 242                                 s->timeout.tv_usec = 1;
 243                         }
 244                 }
 245                 return;
 246         }
 247 }
 248
 249 static ssize_t client_recv_buffer(struct private_client_data *pcd)
 250 {
 251         ssize_t ret = recv_buffer(pcd->fd, pcd->buf + pcd->loaded,
 252                 CLIENT_BUFSIZE - pcd->loaded);
 253         if (!ret)
 254                 return -E_SERVER_EOF;
 255         if (ret > 0)
 256                 pcd->loaded += ret;
 257         return ret;
 258
 259 }
 260
 261 /**
 262  * the post select hook for client commands
 263  *
 264  * \param s pointer to the scheduler
 265  * \param t pointer to the task struct for this command
 266  *
 267  * Depending on the current state of the connection and the status of the read
 268  * and write fd sets of \a s, this function performs the neccessary steps to
 269  * authenticate the connection, to send the commmand given by \a
 270  * t->private_data and to receive para_server's output, if any.
 271  *
 272  * \sa struct sched, struct task
 273  */
 274 void client_post_select(struct sched *s, struct task *t)
 275 {
 276         struct private_client_data *pcd = t->private_data;
 277
 278 //      PARA_INFO_LOG("status %d\n", pcd->status);
 279         t->ret = 1;
 280         if (pcd->fd < 0)
 281                 return;
 282         if (!pcd->check_r && !pcd->check_w)
 283                 return;
 284         if (pcd->check_r && !FD_ISSET(pcd->fd, &s->rfds))
 285                 return;
 286         if (pcd->check_w && !FD_ISSET(pcd->fd, &s->wfds))
 287                 return;
 288         switch (pcd->status) {
 289         case CL_CONNECTED: /* receive welcome message */
 290                 t->ret = client_recv_buffer(pcd);
 291                 if (t->ret > 0)
 292                         pcd->status = CL_RECEIVED_WELCOME;
 293                 return;
 294         case CL_RECEIVED_WELCOME: /* send auth command */
 295                 sprintf(pcd->buf, "auth %s%s", pcd->conf.plain_given?
 296                         "" : "rc4 ", pcd->user);
 297                 PARA_INFO_LOG("--> %s\n", pcd->buf);
 298                 t->ret = send_buffer(pcd->fd, pcd->buf);
 299                 if (t->ret >= 0)
 300                         pcd->status = CL_SENT_AUTH;
 301                 return;
 302         case CL_SENT_AUTH: /* receive challenge number */
 303                 pcd->loaded = 0;
 304                 t->ret = client_recv_buffer(pcd);
 305                 if (t->ret < 0)
 306                         return;
 307                 if (t->ret != 64) {
 308                         t->ret = -E_INVALID_CHALLENGE;
 309                         PARA_ERROR_LOG("received the following: %s\n", pcd->buf);
 310                         return;
 311                 }
 312                 PARA_INFO_LOG("%s", "<-- [challenge]\n");
 313                 /* decrypt challenge number */
 314                 t->ret = para_decrypt_challenge(pcd->key_file, &pcd->challenge_nr,
 315                         (unsigned char *) pcd->buf, 64);
 316                 if (t->ret > 0)
 317                         pcd->status = CL_RECEIVED_CHALLENGE;
 318                 return;
 319         case CL_RECEIVED_CHALLENGE: /* send decrypted challenge */
 320                 PARA_INFO_LOG("--> %lu\n", pcd->challenge_nr);
 321                 t->ret = send_va_buffer(pcd->fd, "%s%lu", CHALLENGE_RESPONSE_MSG,
 322                         pcd->challenge_nr);
 323                 if (t->ret > 0)
 324                         pcd->status = CL_SENT_CH_RESPONSE;
 325                 return;
 326         case CL_SENT_CH_RESPONSE: /* read server response */
 327                 {
 328                 size_t bytes_received;
 329                 unsigned char rc4_buf[2 * RC4_KEY_LEN] = "";
 330                 pcd->loaded = 0;
 331                 t->ret = client_recv_buffer(pcd);
 332                 if (t->ret < 0)
 333                         return;
 334                 bytes_received = t->ret;
 335                 PARA_DEBUG_LOG("++++ server info ++++\n%s\n++++ end of server "
 336                         "info ++++\n", pcd->buf);
 337                 /* check if server has sent "Proceed" message */
 338                 t->ret = -E_CLIENT_AUTH;
 339                 if (!strstr(pcd->buf, PROCEED_MSG))
 340                         return;
 341                 t->ret = 1;
 342                 pcd->status = CL_RECEIVED_PROCEED;
 343                 if (bytes_received < PROCEED_MSG_LEN + 32)
 344                         return;
 345                 PARA_INFO_LOG("%s", "decrypting session key\n");
 346                 t->ret = para_decrypt_buffer(pcd->key_file, rc4_buf,
 347                         (unsigned char *)pcd->buf + PROCEED_MSG_LEN + 1,
 348                         bytes_received - PROCEED_MSG_LEN - 1);
 349                 if (t->ret < 0)
 350                         return;
 351                 RC4_set_key(&pcd->rc4_send_key, RC4_KEY_LEN, rc4_buf);
 352                 RC4_set_key(&pcd->rc4_recv_key, RC4_KEY_LEN, rc4_buf + RC4_KEY_LEN);
 353                 enable_crypt(pcd->fd, rc4_recv, rc4_send, pcd);
 354                 }
 355         case CL_RECEIVED_PROCEED: /* concat args and send command */
 356                 {
 357                 int i;
 358                 char *command = NULL;
 359                 for (i = 0; i < pcd->conf.inputs_num; i++) {
 360                         char *tmp = command;
 361                         command = make_message("%s\n%s", command?
 362                                 command : "", pcd->conf.inputs[i]);
 363                         free(tmp);
 364                 }
 365                 command = para_strcat(command, EOC_MSG "\n");
 366                 PARA_DEBUG_LOG("--> %s\n", command);
 367                 t->ret = send_buffer(pcd->fd, command);
 368                 free(command);
 369                 if (t->ret > 0)
 370                         pcd->status = CL_SENT_COMMAND;
 371                 return;
 372                 }
 373         case CL_SENT_COMMAND:
 374                 pcd->loaded = 0;
 375                 t->ret = client_recv_buffer(pcd);
 376                 if (t->ret < 0)
 377                         return;
 378                 t->ret = -E_HANDSHAKE_COMPLETE;
 379                 if (strstr(pcd->buf, AWAITING_DATA_MSG))
 380                         pcd->status = CL_SENDING;
 381                 else
 382                         pcd->status = CL_RECEIVING;
 383                 return;
 384         case CL_SENDING: /* FIXME: might block */
 385                 PARA_INFO_LOG("loaded: %zd\n", *pcd->in_loaded);
 386                 t->ret = send_bin_buffer(pcd->fd, pcd->inbuf, *pcd->in_loaded);
 387                 if (t->ret < 0)
 388                         return;
 389                 *pcd->in_loaded = 0; /* FIXME: short writes */
 390                 return;
 391         case CL_RECEIVING:
 392                 t->ret = client_recv_buffer(pcd);
 393                 return;
 394         }
 395 }