client_common.c

   1 /*
   2  * Copyright (C) 1997-2007 Andre Noll <maan@systemlinux.org>
   3  *
   4  * Licensed under the GPL v2. For licencing details see COPYING.
   5  */
   6
   7 /** \file client_common.c common functions of para_client and para_audiod */
   8
   9 #include "para.h"
  10 #include "list.h"
  11 #include "sched.h"
  12 #include "client.cmdline.h"
  13 #include "crypt.h"
  14 #include "rc4.h"
  15 #include "net.h"
  16 #include "fd.h"
  17 #include "string.h"
  18 #include "client.cmdline.h"
  19 #include "client.h"
  20 #include "error.h"
  21
  22 /*
  23  * rc4 encrypt data before sending
  24  *
  25  * \param len the number of bytes to encrypt
  26  * \param indata pointer to the input data of length \a len to be encrypted
  27  * \param outdata pointer that holds the encrypted data after return
  28  * \param private_data pointer to the private client data containing
  29  * the rc4 key
  30  * */
  31 static void rc4_send(unsigned long len, const unsigned char *indata,
  32                 unsigned char *outdata, void *private_data)
  33 {
  34         struct private_client_data *pcd = private_data;
  35         RC4(&pcd->rc4_send_key, len, indata, outdata);
  36 }
  37
  38 /*
  39  * rc4 decrypt received data
  40  *
  41  * \param len the number of bytes to decrypt
  42  * \param indata pointer to the input data of length \a len
  43  * \param outdata pointer that holds the decrypted data after return
  44  * \param private_data pointer to the private client data containing
  45  * the rc4 key
  46  * */
  47 static void rc4_recv(unsigned long len, const unsigned char *indata,
  48                 unsigned char *outdata, void *private_data)
  49 {
  50         struct private_client_data *pcd = private_data;
  51         RC4(&pcd->rc4_recv_key, len, indata, outdata);
  52 }
  53
  54 /**
  55  * close the connection to para_server and free all resources
  56  *
  57  * \param pcd pointer to the client data
  58  *
  59  * \sa client_open.
  60  * */
  61 void client_close(struct private_client_data *pcd)
  62 {
  63         if (!pcd)
  64                 return;
  65         if (pcd->fd >= 0) {
  66                 disable_crypt(pcd->fd);
  67                 close(pcd->fd);
  68         }
  69         free(pcd->user);
  70         free(pcd->config_file);
  71         free(pcd->key_file);
  72         client_cmdline_parser_free(&pcd->conf);
  73         free(pcd);
  74 }
  75
  76 static int client_connect(struct private_client_data *pcd)
  77 {
  78         int ret;
  79         struct hostent *he;
  80         struct sockaddr_in their_addr;
  81
  82         pcd->fd = -1;
  83         ret = get_host_info(pcd->conf.hostname_arg, &he);
  84         if (ret < 0)
  85                 return ret;
  86         /* get new socket */
  87         ret = get_socket();
  88         if (ret < 0)
  89                 return ret;
  90         pcd->fd = ret;
  91         /* init their_addr */
  92         init_sockaddr(&their_addr, pcd->conf.server_port_arg, he);
  93         ret = para_connect(pcd->fd, &their_addr);
  94         if (ret < 0)
  95                 goto err_out;
  96         pcd->status = CL_CONNECTED;
  97         ret = mark_fd_nonblock(pcd->fd);
  98         if (ret < 0)
  99                 goto err_out;
 100         pcd->task.pre_select = client_pre_select;
 101         pcd->task.post_select = client_post_select;
 102         pcd->task.private_data = pcd;
 103         sprintf(pcd->task.status, "client");
 104         register_task(&pcd->task);
 105         return 1;
 106 err_out:
 107         close(pcd->fd);
 108         pcd->fd = -1;
 109         return ret;
 110 }
 111
 112 /**
 113  * open connection to para_server
 114  *
 115  * \param argc usual argument count
 116  * \param argv usual argument vector
 117  * \param pcd_ptr points to dynamically allocated and initialized private client data
 118  * upon successful return
 119  *
 120  * Check the command line options given by \a argc and argv, set default values
 121  * for user name and rsa key file, read further option from the config file.
 122  * Finally, establish a connection to para_server.
 123  *
 124  * \return Positive on success, negative on errors.
 125  */
 126 int client_open(int argc, char *argv[], struct private_client_data **pcd_ptr)
 127 {
 128         char *home = para_homedir();
 129         struct stat statbuf;
 130         int ret;
 131         struct private_client_data *pcd =
 132                 para_calloc(sizeof(struct private_client_data));
 133
 134         *pcd_ptr = pcd;
 135         pcd->fd = -1;
 136         ret = client_cmdline_parser(argc, argv, &pcd->conf);
 137         HANDLE_VERSION_FLAG("client", pcd->conf);
 138         ret = -E_CLIENT_SYNTAX;
 139         if (!pcd->conf.inputs_num)
 140                 goto out;
 141         pcd->user = pcd->conf.user_given?
 142                 para_strdup(pcd->conf.user_arg) : para_logname();
 143
 144         pcd->key_file = pcd->conf.key_file_given?
 145                 para_strdup(pcd->conf.key_file_arg) :
 146                 make_message("%s/.paraslash/key.%s", home, pcd->user);
 147
 148         pcd->config_file = pcd->conf.config_file_given?
 149                 para_strdup(pcd->conf.config_file_arg) :
 150                 make_message("%s/.paraslash/client.conf", home);
 151         ret = stat(pcd->config_file, &statbuf);
 152         if (ret && pcd->conf.config_file_given) {
 153                 ret = -E_NO_CONFIG;
 154                 goto out;
 155         }
 156         if (!ret)
 157                 client_cmdline_parser_configfile(pcd->config_file,
 158                         &pcd->conf, 0, 0, 0);
 159         ret = 1;
 160         PARA_INFO_LOG("loglevel: %d\n", pcd->conf.loglevel_arg);
 161         PARA_INFO_LOG("config_file: %s\n", pcd->config_file);
 162         PARA_INFO_LOG("key_file: %s\n", pcd->key_file);
 163         PARA_NOTICE_LOG("connecting %s:%d\n", pcd->conf.hostname_arg,
 164                 pcd->conf.server_port_arg);
 165         ret = client_connect(pcd);
 166 out:
 167         free(home);
 168         if (ret < 0) {
 169                 PARA_ERROR_LOG("%s\n", PARA_STRERROR(-ret));
 170                 client_close(pcd);
 171                 *pcd_ptr = NULL;
 172         }
 173         return ret;
 174 }
 175
 176 /**
 177  * the preselect hook for server commands
 178  *
 179  * \param s pointer to the scheduler
 180  * \param t pointer to the task struct for this command
 181  *
 182  * The task pointer must contain a pointer to the initialized client data
 183  * structure as it is returned by client_open().
 184  *
 185  * This function checks the state of the connection and adds the file descriptor
 186  * of the connection to the read or write fd set of \a s accordingly.
 187  *
 188  * \sa register_task() client_open(), struct sched, struct task
 189  */
 190 void client_pre_select(struct sched *s, struct task *t)
 191 {
 192         struct private_client_data *pcd = t->private_data;
 193
 194         t->ret = 1;
 195         pcd->check_r = 0;
 196         pcd->check_w = 0;
 197         if (pcd->fd < 0)
 198                 return;
 199         switch (pcd->status) {
 200         case CL_CONNECTED:
 201         case CL_SENT_AUTH:
 202         case CL_SENT_CH_RESPONSE:
 203         case CL_SENT_COMMAND:
 204                 para_fd_set(pcd->fd, &s->rfds, &s->max_fileno);
 205                 pcd->check_r = 1;
 206                 return;
 207
 208         case CL_RECEIVED_WELCOME:
 209         case CL_RECEIVED_CHALLENGE:
 210         case CL_RECEIVED_PROCEED:
 211                 para_fd_set(pcd->fd, &s->wfds, &s->max_fileno);
 212                 pcd->check_w = 1;
 213                 return;
 214
 215         case CL_RECEIVING:
 216                 if (pcd->loaded < CLIENT_BUFSIZE - 1) {
 217                         para_fd_set(pcd->fd, &s->rfds, &s->max_fileno);
 218                         pcd->check_r = 1;
 219                 }
 220                 return;
 221         case CL_SENDING:
 222                 if (*pcd->in_loaded) {
 223                         PARA_INFO_LOG("loaded: %zd\n", *pcd->in_loaded);
 224                         para_fd_set(pcd->fd, &s->wfds, &s->max_fileno);
 225                         pcd->check_w = 1;
 226                 } else {
 227                         if (*pcd->in_eof) {
 228                                 t->ret = -E_INPUT_EOF;
 229                                 s->timeout.tv_sec = 0;
 230                                 s->timeout.tv_usec = 1;
 231                         }
 232                 }
 233                 return;
 234         }
 235 }
 236
 237 static ssize_t client_recv_buffer(struct private_client_data *pcd)
 238 {
 239         ssize_t ret = recv_buffer(pcd->fd, pcd->buf + pcd->loaded,
 240                 CLIENT_BUFSIZE - pcd->loaded);
 241         if (!ret)
 242                 return -E_SERVER_EOF;
 243         if (ret > 0)
 244                 pcd->loaded += ret;
 245         return ret;
 246
 247 }
 248
 249 /**
 250  * the post select hook for client commands
 251  *
 252  * \param s pointer to the scheduler
 253  * \param t pointer to the task struct for this command
 254  *
 255  * Depending on the current state of the connection and the status of the read
 256  * and write fd sets of \a s, this function performs the neccessary steps to
 257  * authenticate the connection, to send the commmand given by \a
 258  * t->private_data and to receive para_server's output, if any.
 259  *
 260  * \sa struct sched, struct task
 261  */
 262 void client_post_select(struct sched *s, struct task *t)
 263 {
 264         struct private_client_data *pcd = t->private_data;
 265
 266 //      PARA_INFO_LOG("status %d\n", pcd->status);
 267         t->ret = 1;
 268         if (pcd->fd < 0)
 269                 return;
 270         if (!pcd->check_r && !pcd->check_w)
 271                 return;
 272         if (pcd->check_r && !FD_ISSET(pcd->fd, &s->rfds))
 273                 return;
 274         if (pcd->check_w && !FD_ISSET(pcd->fd, &s->wfds))
 275                 return;
 276         switch (pcd->status) {
 277         case CL_CONNECTED: /* receive welcome message */
 278                 t->ret = client_recv_buffer(pcd);
 279                 if (t->ret > 0)
 280                         pcd->status = CL_RECEIVED_WELCOME;
 281                 return;
 282         case CL_RECEIVED_WELCOME: /* send auth command */
 283                 sprintf(pcd->buf, "auth %s%s", pcd->conf.plain_given?
 284                         "" : "rc4 ", pcd->user);
 285                 PARA_INFO_LOG("--> %s\n", pcd->buf);
 286                 t->ret = send_buffer(pcd->fd, pcd->buf);
 287                 if (t->ret >= 0)
 288                         pcd->status = CL_SENT_AUTH;
 289                 return;
 290         case CL_SENT_AUTH: /* receive challenge number */
 291                 pcd->loaded = 0;
 292                 t->ret = client_recv_buffer(pcd);
 293                 if (t->ret < 0)
 294                         return;
 295                 if (t->ret != 64) {
 296                         t->ret = -E_INVALID_CHALLENGE;
 297                         PARA_ERROR_LOG("received the following: %s\n", pcd->buf);
 298                         return;
 299                 }
 300                 PARA_INFO_LOG("%s", "<-- [challenge]\n");
 301                 /* decrypt challenge number */
 302                 t->ret = para_decrypt_challenge(pcd->key_file, &pcd->challenge_nr,
 303                         (unsigned char *) pcd->buf, 64);
 304                 if (t->ret > 0)
 305                         pcd->status = CL_RECEIVED_CHALLENGE;
 306                 return;
 307         case CL_RECEIVED_CHALLENGE: /* send decrypted challenge */
 308                 PARA_INFO_LOG("--> %lu\n", pcd->challenge_nr);
 309                 t->ret = send_va_buffer(pcd->fd, "%s%lu", CHALLENGE_RESPONSE_MSG,
 310                         pcd->challenge_nr);
 311                 if (t->ret > 0)
 312                         pcd->status = CL_SENT_CH_RESPONSE;
 313                 return;
 314         case CL_SENT_CH_RESPONSE: /* read server response */
 315                 {
 316                 size_t bytes_received;
 317                 unsigned char rc4_buf[2 * RC4_KEY_LEN] = "";
 318                 pcd->loaded = 0;
 319                 t->ret = client_recv_buffer(pcd);
 320                 if (t->ret < 0)
 321                         return;
 322                 bytes_received = t->ret;
 323                 PARA_DEBUG_LOG("++++ server info ++++\n%s\n++++ end of server "
 324                         "info ++++\n", pcd->buf);
 325                 /* check if server has sent "Proceed" message */
 326                 t->ret = -E_CLIENT_AUTH;
 327                 if (!strstr(pcd->buf, PROCEED_MSG))
 328                         return;
 329                 t->ret = 1;
 330                 pcd->status = CL_RECEIVED_PROCEED;
 331                 if (bytes_received < PROCEED_MSG_LEN + 32)
 332                         return;
 333                 PARA_INFO_LOG("%s", "decrypting session key\n");
 334                 t->ret = para_decrypt_buffer(pcd->key_file, rc4_buf,
 335                         (unsigned char *)pcd->buf + PROCEED_MSG_LEN + 1,
 336                         bytes_received - PROCEED_MSG_LEN - 1);
 337                 if (t->ret < 0)
 338                         return;
 339                 RC4_set_key(&pcd->rc4_send_key, RC4_KEY_LEN, rc4_buf);
 340                 RC4_set_key(&pcd->rc4_recv_key, RC4_KEY_LEN, rc4_buf + RC4_KEY_LEN);
 341                 enable_crypt(pcd->fd, rc4_recv, rc4_send, pcd);
 342                 }
 343         case CL_RECEIVED_PROCEED: /* concat args and send command */
 344                 {
 345                 int i;
 346                 char *command = NULL;
 347                 for (i = 0; i < pcd->conf.inputs_num; i++) {
 348                         char *tmp = command;
 349                         command = make_message("%s\n%s", command?
 350                                 command : "", pcd->conf.inputs[i]);
 351                         free(tmp);
 352                 }
 353                 command = para_strcat(command, EOC_MSG "\n");
 354                 PARA_DEBUG_LOG("--> %s\n", command);
 355                 t->ret = send_buffer(pcd->fd, command);
 356                 free(command);
 357                 if (t->ret > 0)
 358                         pcd->status = CL_SENT_COMMAND;
 359                 return;
 360                 }
 361         case CL_SENT_COMMAND:
 362                 pcd->loaded = 0;
 363                 t->ret = client_recv_buffer(pcd);
 364                 if (t->ret < 0)
 365                         return;
 366                 t->ret = -E_HANDSHAKE_COMPLETE;
 367                 if (strstr(pcd->buf, AWAITING_DATA_MSG))
 368                         pcd->status = CL_SENDING;
 369                 else
 370                         pcd->status = CL_RECEIVING;
 371                 return;
 372         case CL_SENDING: /* FIXME: might block */
 373                 PARA_INFO_LOG("loaded: %zd\n", *pcd->in_loaded);
 374                 t->ret = send_bin_buffer(pcd->fd, pcd->inbuf, *pcd->in_loaded);
 375                 if (t->ret < 0)
 376                         return;
 377                 *pcd->in_loaded = 0; /* FIXME: short writes */
 378                 return;
 379         case CL_RECEIVING:
 380                 t->ret = client_recv_buffer(pcd);
 381                 return;
 382         }
 383 }