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