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         free(pcd);
  85 }
  86
  87 static int client_connect(struct private_client_data *pcd)
  88 {
  89         int ret;
  90         struct hostent *he;
  91         struct sockaddr_in their_addr;
  92
  93         pcd->fd = -1;
  94         ret = get_host_info(pcd->conf.hostname_arg, &he);
  95         if (ret < 0)
  96                 return ret;
  97         /* get new socket */
  98         ret = get_socket();
  99         if (ret < 0)
 100                 return ret;
 101         pcd->fd = ret;
 102         /* init their_addr */
 103         init_sockaddr(&their_addr, pcd->conf.server_port_arg, he);
 104         ret = para_connect(pcd->fd, &their_addr);
 105         if (ret < 0)
 106                 goto err_out;
 107         pcd->status = CL_CONNECTED;
 108         ret = mark_fd_nonblock(pcd->fd);
 109         if (ret < 0)
 110                 goto err_out;
 111         pcd->task.pre_select = client_pre_select;
 112         pcd->task.post_select = client_post_select;
 113         pcd->task.private_data = pcd;
 114         sprintf(pcd->task.status, "client");
 115         register_task(&pcd->task);
 116         return 1;
 117 err_out:
 118         close(pcd->fd);
 119         pcd->fd = -1;
 120         return ret;
 121 }
 122
 123 /**
 124  * open connection to para_server
 125  *
 126  * \param argc usual argument count
 127  * \param argv usual argument vector
 128  * \param pcd_ptr points to dynamically allocated and initialized private client data
 129  * upon successful return
 130  *
 131  * Check the command line options given by \a argc and argv, set default values
 132  * for user name and rsa key file, read further option from the config file.
 133  * Finally, establish a connection to para_server.
 134  *
 135  * \return Positive on success, negative on errors.
 136  */
 137 int client_open(int argc, char *argv[], struct private_client_data **pcd_ptr)
 138 {
 139         char *home = para_homedir();
 140         struct stat statbuf;
 141         int ret;
 142         struct private_client_data *pcd =
 143                 para_calloc(sizeof(struct private_client_data));
 144
 145         *pcd_ptr = pcd;
 146         pcd->fd = -1;
 147         ret = client_cmdline_parser(argc, argv, &pcd->conf);
 148         HANDLE_VERSION_FLAG("client", pcd->conf);
 149         ret = -E_CLIENT_SYNTAX;
 150         if (!pcd->conf.inputs_num)
 151                 goto out;
 152         pcd->user = pcd->conf.user_given?
 153                 para_strdup(pcd->conf.user_arg) : para_logname();
 154
 155         pcd->key_file = pcd->conf.key_file_given?
 156                 para_strdup(pcd->conf.key_file_arg) :
 157                 make_message("%s/.paraslash/key.%s", home, pcd->user);
 158
 159         pcd->config_file = pcd->conf.config_file_given?
 160                 para_strdup(pcd->conf.config_file_arg) :
 161                 make_message("%s/.paraslash/client.conf", home);
 162         ret = stat(pcd->config_file, &statbuf);
 163         if (ret && pcd->conf.config_file_given) {
 164                 ret = -E_NO_CONFIG;
 165                 goto out;
 166         }
 167         if (!ret)
 168                 client_cmdline_parser_configfile(pcd->config_file,
 169                         &pcd->conf, 0, 0, 0);
 170         ret = 1;
 171         PARA_INFO_LOG("loglevel: %d\n", pcd->conf.loglevel_arg);
 172         PARA_INFO_LOG("config_file: %s\n", pcd->config_file);
 173         PARA_INFO_LOG("key_file: %s\n", pcd->key_file);
 174         PARA_NOTICE_LOG("connecting %s:%d\n", pcd->conf.hostname_arg,
 175                 pcd->conf.server_port_arg);
 176         ret = client_connect(pcd);
 177 out:
 178         free(home);
 179         if (ret < 0) {
 180                 PARA_ERROR_LOG("%s\n", PARA_STRERROR(-ret));
 181                 client_close(pcd);
 182                 *pcd_ptr = NULL;
 183         }
 184         return ret;
 185 }
 186
 187 /**
 188  * the preselect hook for server commands
 189  *
 190  * \param s pointer to the scheduler
 191  * \param t pointer to the task struct for this command
 192  *
 193  * The task pointer must contain a pointer to the initialized client data
 194  * structure as it is returned by client_open().
 195  *
 196  * This function checks the state of the connection and adds the file descriptor
 197  * of the connection to the read or write fd set of \a s accordingly.
 198  *
 199  * \sa register_task() client_open(), struct sched, struct task
 200  */
 201 void client_pre_select(struct sched *s, struct task *t)
 202 {
 203         struct private_client_data *pcd = t->private_data;
 204
 205         t->ret = 1;
 206         pcd->check_r = 0;
 207         pcd->check_w = 0;
 208         if (pcd->fd < 0)
 209                 return;
 210         switch (pcd->status) {
 211         case CL_CONNECTED:
 212         case CL_SENT_AUTH:
 213         case CL_SENT_CH_RESPONSE:
 214         case CL_SENT_COMMAND:
 215                 para_fd_set(pcd->fd, &s->rfds, &s->max_fileno);
 216                 pcd->check_r = 1;
 217                 return;
 218
 219         case CL_RECEIVED_WELCOME:
 220         case CL_RECEIVED_CHALLENGE:
 221         case CL_RECEIVED_PROCEED:
 222                 para_fd_set(pcd->fd, &s->wfds, &s->max_fileno);
 223                 pcd->check_w = 1;
 224                 return;
 225
 226         case CL_RECEIVING:
 227                 if (pcd->loaded < CLIENT_BUFSIZE - 1) {
 228                         para_fd_set(pcd->fd, &s->rfds, &s->max_fileno);
 229                         pcd->check_r = 1;
 230                 }
 231                 return;
 232         case CL_SENDING:
 233                 if (*pcd->in_loaded) {
 234                         PARA_INFO_LOG("loaded: %zd\n", *pcd->in_loaded);
 235                         para_fd_set(pcd->fd, &s->wfds, &s->max_fileno);
 236                         pcd->check_w = 1;
 237                 } else {
 238                         if (*pcd->in_eof) {
 239                                 t->ret = -E_INPUT_EOF;
 240                                 s->timeout.tv_sec = 0;
 241                                 s->timeout.tv_usec = 1;
 242                         }
 243                 }
 244                 return;
 245         }
 246 }
 247
 248 static ssize_t client_recv_buffer(struct private_client_data *pcd)
 249 {
 250         ssize_t ret = recv_buffer(pcd->fd, pcd->buf + pcd->loaded,
 251                 CLIENT_BUFSIZE - pcd->loaded);
 252         if (!ret)
 253                 return -E_SERVER_EOF;
 254         if (ret > 0)
 255                 pcd->loaded += ret;
 256         return ret;
 257
 258 }
 259
 260 /**
 261  * the post select hook for client commands
 262  *
 263  * \param s pointer to the scheduler
 264  * \param t pointer to the task struct for this command
 265  *
 266  * Depending on the current state of the connection and the status of the read
 267  * and write fd sets of \a s, this function performs the neccessary steps to
 268  * authenticate the connection, to send the commmand given by \a
 269  * t->private_data and to receive para_server's output, if any.
 270  *
 271  * \sa struct sched, struct task
 272  */
 273 void client_post_select(struct sched *s, struct task *t)
 274 {
 275         struct private_client_data *pcd = t->private_data;
 276
 277 //      PARA_INFO_LOG("status %d\n", pcd->status);
 278         t->ret = 1;
 279         if (pcd->fd < 0)
 280                 return;
 281         if (!pcd->check_r && !pcd->check_w)
 282                 return;
 283         if (pcd->check_r && !FD_ISSET(pcd->fd, &s->rfds))
 284                 return;
 285         if (pcd->check_w && !FD_ISSET(pcd->fd, &s->wfds))
 286                 return;
 287         switch (pcd->status) {
 288         case CL_CONNECTED: /* receive welcome message */
 289                 t->ret = client_recv_buffer(pcd);
 290                 if (t->ret > 0)
 291                         pcd->status = CL_RECEIVED_WELCOME;
 292                 return;
 293         case CL_RECEIVED_WELCOME: /* send auth command */
 294                 sprintf(pcd->buf, "auth %s%s", pcd->conf.plain_given?
 295                         "" : "rc4 ", pcd->user);
 296                 PARA_INFO_LOG("--> %s\n", pcd->buf);
 297                 t->ret = send_buffer(pcd->fd, pcd->buf);
 298                 if (t->ret >= 0)
 299                         pcd->status = CL_SENT_AUTH;
 300                 return;
 301         case CL_SENT_AUTH: /* receive challenge number */
 302                 pcd->loaded = 0;
 303                 t->ret = client_recv_buffer(pcd);
 304                 if (t->ret < 0)
 305                         return;
 306                 if (t->ret != 64) {
 307                         t->ret = -E_INVALID_CHALLENGE;
 308                         PARA_ERROR_LOG("received the following: %s\n", pcd->buf);
 309                         return;
 310                 }
 311                 PARA_INFO_LOG("%s", "<-- [challenge]\n");
 312                 /* decrypt challenge number */
 313                 t->ret = para_decrypt_challenge(pcd->key_file, &pcd->challenge_nr,
 314                         (unsigned char *) pcd->buf, 64);
 315                 if (t->ret > 0)
 316                         pcd->status = CL_RECEIVED_CHALLENGE;
 317                 return;
 318         case CL_RECEIVED_CHALLENGE: /* send decrypted challenge */
 319                 PARA_INFO_LOG("--> %lu\n", pcd->challenge_nr);
 320                 t->ret = send_va_buffer(pcd->fd, "%s%lu", CHALLENGE_RESPONSE_MSG,
 321                         pcd->challenge_nr);
 322                 if (t->ret > 0)
 323                         pcd->status = CL_SENT_CH_RESPONSE;
 324                 return;
 325         case CL_SENT_CH_RESPONSE: /* read server response */
 326                 {
 327                 size_t bytes_received;
 328                 unsigned char rc4_buf[2 * RC4_KEY_LEN] = "";
 329                 pcd->loaded = 0;
 330                 t->ret = client_recv_buffer(pcd);
 331                 if (t->ret < 0)
 332                         return;
 333                 bytes_received = t->ret;
 334                 PARA_DEBUG_LOG("++++ server info ++++\n%s\n++++ end of server "
 335                         "info ++++\n", pcd->buf);
 336                 /* check if server has sent "Proceed" message */
 337                 t->ret = -E_CLIENT_AUTH;
 338                 if (!strstr(pcd->buf, PROCEED_MSG))
 339                         return;
 340                 t->ret = 1;
 341                 pcd->status = CL_RECEIVED_PROCEED;
 342                 if (bytes_received < PROCEED_MSG_LEN + 32)
 343                         return;
 344                 PARA_INFO_LOG("%s", "decrypting session key\n");
 345                 t->ret = para_decrypt_buffer(pcd->key_file, rc4_buf,
 346                         (unsigned char *)pcd->buf + PROCEED_MSG_LEN + 1,
 347                         bytes_received - PROCEED_MSG_LEN - 1);
 348                 if (t->ret < 0)
 349                         return;
 350                 RC4_set_key(&pcd->rc4_send_key, RC4_KEY_LEN, rc4_buf);
 351                 RC4_set_key(&pcd->rc4_recv_key, RC4_KEY_LEN, rc4_buf + RC4_KEY_LEN);
 352                 enable_crypt(pcd->fd, rc4_recv, rc4_send, pcd);
 353                 }
 354         case CL_RECEIVED_PROCEED: /* concat args and send command */
 355                 {
 356                 int i;
 357                 char *command = NULL;
 358                 for (i = 0; i < pcd->conf.inputs_num; i++) {
 359                         char *tmp = command;
 360                         command = make_message("%s\n%s", command?
 361                                 command : "", pcd->conf.inputs[i]);
 362                         free(tmp);
 363                 }
 364                 command = para_strcat(command, EOC_MSG "\n");
 365                 PARA_DEBUG_LOG("--> %s\n", command);
 366                 t->ret = send_buffer(pcd->fd, command);
 367                 free(command);
 368                 if (t->ret > 0)
 369                         pcd->status = CL_SENT_COMMAND;
 370                 return;
 371                 }
 372         case CL_SENT_COMMAND:
 373                 pcd->loaded = 0;
 374                 t->ret = client_recv_buffer(pcd);
 375                 if (t->ret < 0)
 376                         return;
 377                 t->ret = -E_HANDSHAKE_COMPLETE;
 378                 if (strstr(pcd->buf, AWAITING_DATA_MSG))
 379                         pcd->status = CL_SENDING;
 380                 else
 381                         pcd->status = CL_RECEIVING;
 382                 return;
 383         case CL_SENDING: /* FIXME: might block */
 384                 PARA_INFO_LOG("loaded: %zd\n", *pcd->in_loaded);
 385                 t->ret = send_bin_buffer(pcd->fd, pcd->inbuf, *pcd->in_loaded);
 386                 if (t->ret < 0)
 387                         return;
 388                 *pcd->in_loaded = 0; /* FIXME: short writes */
 389                 return;
 390         case CL_RECEIVING:
 391                 t->ret = client_recv_buffer(pcd);
 392                 return;
 393         }
 394 }