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 Result-pointer that holds the encrypted data.
  31  * \param private_data Contains the rc4 key.
  32  */
  33 static void rc4_send(unsigned long len, const unsigned char *indata,
  34                 unsigned char *outdata, void *private_data)
  35 {
  36         struct private_client_data *pcd = private_data;
  37         RC4(&pcd->rc4_send_key, len, indata, outdata);
  38 }
  39
  40 /*
  41  * Rc4-decrypt received data.
  42  *
  43  * Parameters are identical to those of rc4_send.
  44  */
  45 static void rc4_recv(unsigned long len, const unsigned char *indata,
  46                 unsigned char *outdata, void *private_data)
  47 {
  48         struct private_client_data *pcd = private_data;
  49         RC4(&pcd->rc4_recv_key, len, indata, outdata);
  50 }
  51
  52 /**
  53  * Close the connection to para_server and free all resources.
  54  *
  55  * \param pcd Pointer to the client data.
  56  *
  57  * \sa client_open.
  58  */
  59 void client_close(struct private_client_data *pcd)
  60 {
  61         if (!pcd)
  62                 return;
  63         if (pcd->fd >= 0) {
  64                 disable_crypt(pcd->fd);
  65                 close(pcd->fd);
  66         }
  67         free(pcd->user);
  68         free(pcd->config_file);
  69         free(pcd->key_file);
  70         client_cmdline_parser_free(&pcd->conf);
  71         free(pcd);
  72 }
  73
  74 /* connect to para_server and register the client task */
  75 static int client_connect(struct private_client_data *pcd)
  76 {
  77         int ret;
  78
  79         pcd->fd = -1;
  80         ret = makesock(AF_UNSPEC, IPPROTO_TCP, 0, pcd->conf.hostname_arg,
  81                 pcd->conf.server_port_arg);
  82         if (ret < 0)
  83                 return ret;
  84         pcd->fd = ret;
  85         pcd->status = CL_CONNECTED;
  86         ret = mark_fd_nonblocking(pcd->fd);
  87         if (ret < 0)
  88                 goto err_out;
  89         pcd->task.pre_select = client_pre_select;
  90         pcd->task.post_select = client_post_select;
  91         pcd->task.private_data = pcd;
  92         sprintf(pcd->task.status, "client");
  93         register_task(&pcd->task);
  94         return 1;
  95 err_out:
  96         close(pcd->fd);
  97         pcd->fd = -1;
  98         return ret;
  99 }
 100
 101 /**
 102  * Open connection to para_server.
 103  *
 104  * \param argc Usual argument count.
 105  * \param argv Usual argument vector.
 106  * \param pcd_ptr Points to dynamically allocated and initialized private client data
 107  * upon successful return.
 108  *
 109  * Check the command line options given by \a argc and argv, set default values
 110  * for user name and rsa key file, read further option from the config file.
 111  * Finally, establish a connection to para_server.
 112  *
 113  * \return Standard.
 114  */
 115 int client_open(int argc, char *argv[], struct private_client_data **pcd_ptr)
 116 {
 117         char *home = para_homedir();
 118         struct stat statbuf;
 119         int ret;
 120         struct private_client_data *pcd =
 121                 para_calloc(sizeof(struct private_client_data));
 122
 123         *pcd_ptr = pcd;
 124         pcd->fd = -1;
 125         ret = client_cmdline_parser(argc, argv, &pcd->conf);
 126         HANDLE_VERSION_FLAG("client", pcd->conf);
 127         ret = -E_CLIENT_SYNTAX;
 128         if (!pcd->conf.inputs_num)
 129                 goto out;
 130         pcd->user = pcd->conf.user_given?
 131                 para_strdup(pcd->conf.user_arg) : para_logname();
 132
 133         pcd->key_file = pcd->conf.key_file_given?
 134                 para_strdup(pcd->conf.key_file_arg) :
 135                 make_message("%s/.paraslash/key.%s", home, pcd->user);
 136
 137         pcd->config_file = pcd->conf.config_file_given?
 138                 para_strdup(pcd->conf.config_file_arg) :
 139                 make_message("%s/.paraslash/client.conf", home);
 140         ret = stat(pcd->config_file, &statbuf);
 141         if (ret && pcd->conf.config_file_given) {
 142                 ret = -E_NO_CONFIG;
 143                 goto out;
 144         }
 145         if (!ret) {
 146                 struct client_cmdline_parser_params params = {
 147                         .override = 0,
 148                         .initialize = 0,
 149                         .check_required = 0,
 150                         .check_ambiguity = 0
 151                 };
 152                 client_cmdline_parser_config_file(pcd->config_file,
 153                         &pcd->conf, &params);
 154         }
 155         ret = 1;
 156         PARA_INFO_LOG("loglevel: %d\n", pcd->conf.loglevel_arg);
 157         PARA_INFO_LOG("config_file: %s\n", pcd->config_file);
 158         PARA_INFO_LOG("key_file: %s\n", pcd->key_file);
 159         PARA_NOTICE_LOG("connecting %s:%d\n", pcd->conf.hostname_arg,
 160                 pcd->conf.server_port_arg);
 161         ret = client_connect(pcd);
 162 out:
 163         free(home);
 164         if (ret < 0) {
 165                 PARA_ERROR_LOG("%s\n", PARA_STRERROR(-ret));
 166                 client_close(pcd);
 167                 *pcd_ptr = NULL;
 168         }
 169         return ret;
 170 }
 171
 172 /**
 173  * The preselect hook for server commands.
 174  *
 175  * \param s Pointer to the scheduler.
 176  * \param t Pointer to the task struct for this command.
 177  *
 178  * The task pointer must contain a pointer to the initialized client data
 179  * structure as it is returned by client_open().
 180  *
 181  * This function checks the state of the connection and adds the file descriptor
 182  * of the connection to the read or write fd set of \a s accordingly.
 183  *
 184  * \sa register_task() client_open(), struct sched, struct task.
 185  */
 186 void client_pre_select(struct sched *s, struct task *t)
 187 {
 188         struct private_client_data *pcd = t->private_data;
 189
 190         t->ret = 1;
 191         pcd->check_r = 0;
 192         pcd->check_w = 0;
 193         if (pcd->fd < 0)
 194                 return;
 195         switch (pcd->status) {
 196         case CL_CONNECTED:
 197         case CL_SENT_AUTH:
 198         case CL_SENT_CH_RESPONSE:
 199         case CL_SENT_COMMAND:
 200                 para_fd_set(pcd->fd, &s->rfds, &s->max_fileno);
 201                 pcd->check_r = 1;
 202                 return;
 203
 204         case CL_RECEIVED_WELCOME:
 205         case CL_RECEIVED_CHALLENGE:
 206         case CL_RECEIVED_PROCEED:
 207                 para_fd_set(pcd->fd, &s->wfds, &s->max_fileno);
 208                 pcd->check_w = 1;
 209                 return;
 210
 211         case CL_RECEIVING:
 212                 if (pcd->loaded < CLIENT_BUFSIZE - 1) {
 213                         para_fd_set(pcd->fd, &s->rfds, &s->max_fileno);
 214                         pcd->check_r = 1;
 215                 }
 216                 return;
 217         case CL_SENDING:
 218                 if (*pcd->in_loaded) {
 219                         PARA_INFO_LOG("loaded: %zd\n", *pcd->in_loaded);
 220                         para_fd_set(pcd->fd, &s->wfds, &s->max_fileno);
 221                         pcd->check_w = 1;
 222                 } else {
 223                         if (*pcd->in_error) {
 224                                 t->ret = *pcd->in_error;
 225                                 s->timeout.tv_sec = 0;
 226                                 s->timeout.tv_usec = 1;
 227                         }
 228                 }
 229                 return;
 230         }
 231 }
 232
 233 static ssize_t client_recv_buffer(struct private_client_data *pcd)
 234 {
 235         ssize_t ret = recv_buffer(pcd->fd, pcd->buf + pcd->loaded,
 236                 CLIENT_BUFSIZE - pcd->loaded);
 237         if (!ret)
 238                 return -E_SERVER_EOF;
 239         if (ret > 0)
 240                 pcd->loaded += ret;
 241         return ret;
 242
 243 }
 244
 245 /**
 246  * The post select hook for client commands.
 247  *
 248  * \param s Pointer to the scheduler.
 249  * \param t Pointer to the task struct for this command.
 250  *
 251  * Depending on the current state of the connection and the status of the read
 252  * and write fd sets of \a s, this function performs the necessary steps to
 253  * authenticate the connection, to send the command given by \a t->private_data
 254  * and to receive para_server's output, if any.
 255  *
 256  * \sa struct sched, struct task.
 257  */
 258 void client_post_select(struct sched *s, struct task *t)
 259 {
 260         struct private_client_data *pcd = t->private_data;
 261
 262 //      PARA_INFO_LOG("status %d\n", pcd->status);
 263         t->ret = 1;
 264         if (pcd->fd < 0)
 265                 return;
 266         if (!pcd->check_r && !pcd->check_w)
 267                 return;
 268         if (pcd->check_r && !FD_ISSET(pcd->fd, &s->rfds))
 269                 return;
 270         if (pcd->check_w && !FD_ISSET(pcd->fd, &s->wfds))
 271                 return;
 272         switch (pcd->status) {
 273         case CL_CONNECTED: /* receive welcome message */
 274                 t->ret = client_recv_buffer(pcd);
 275                 if (t->ret > 0)
 276                         pcd->status = CL_RECEIVED_WELCOME;
 277                 return;
 278         case CL_RECEIVED_WELCOME: /* send auth command */
 279                 sprintf(pcd->buf, "auth %s%s", pcd->conf.plain_given?
 280                         "" : "rc4 ", pcd->user);
 281                 PARA_INFO_LOG("--> %s\n", pcd->buf);
 282                 t->ret = send_buffer(pcd->fd, pcd->buf);
 283                 if (t->ret >= 0)
 284                         pcd->status = CL_SENT_AUTH;
 285                 return;
 286         case CL_SENT_AUTH: /* receive challenge number */
 287                 pcd->loaded = 0;
 288                 t->ret = client_recv_buffer(pcd);
 289                 if (t->ret < 0)
 290                         return;
 291                 if (t->ret != 64) {
 292                         t->ret = -E_INVALID_CHALLENGE;
 293                         PARA_ERROR_LOG("received the following: %s\n", pcd->buf);
 294                         return;
 295                 }
 296                 PARA_INFO_LOG("%s", "<-- [challenge]\n");
 297                 /* decrypt challenge number */
 298                 t->ret = para_decrypt_challenge(pcd->key_file, &pcd->challenge_nr,
 299                         (unsigned char *) pcd->buf, 64);
 300                 if (t->ret > 0)
 301                         pcd->status = CL_RECEIVED_CHALLENGE;
 302                 return;
 303         case CL_RECEIVED_CHALLENGE: /* send decrypted challenge */
 304                 PARA_INFO_LOG("--> %lu\n", pcd->challenge_nr);
 305                 t->ret = send_va_buffer(pcd->fd, "%s%lu", CHALLENGE_RESPONSE_MSG,
 306                         pcd->challenge_nr);
 307                 if (t->ret > 0)
 308                         pcd->status = CL_SENT_CH_RESPONSE;
 309                 return;
 310         case CL_SENT_CH_RESPONSE: /* read server response */
 311                 {
 312                 size_t bytes_received;
 313                 unsigned char rc4_buf[2 * RC4_KEY_LEN] = "";
 314                 pcd->loaded = 0;
 315                 t->ret = client_recv_buffer(pcd);
 316                 if (t->ret < 0)
 317                         return;
 318                 bytes_received = t->ret;
 319                 PARA_DEBUG_LOG("++++ server info ++++\n%s\n++++ end of server "
 320                         "info ++++\n", pcd->buf);
 321                 /* check if server has sent "Proceed" message */
 322                 t->ret = -E_CLIENT_AUTH;
 323                 if (!strstr(pcd->buf, PROCEED_MSG))
 324                         return;
 325                 t->ret = 1;
 326                 pcd->status = CL_RECEIVED_PROCEED;
 327                 if (bytes_received < PROCEED_MSG_LEN + 32)
 328                         return;
 329                 PARA_INFO_LOG("%s", "decrypting session key\n");
 330                 t->ret = para_decrypt_buffer(pcd->key_file, rc4_buf,
 331                         (unsigned char *)pcd->buf + PROCEED_MSG_LEN + 1,
 332                         bytes_received - PROCEED_MSG_LEN - 1);
 333                 if (t->ret < 0)
 334                         return;
 335                 RC4_set_key(&pcd->rc4_send_key, RC4_KEY_LEN, rc4_buf);
 336                 RC4_set_key(&pcd->rc4_recv_key, RC4_KEY_LEN, rc4_buf + RC4_KEY_LEN);
 337                 enable_crypt(pcd->fd, rc4_recv, rc4_send, pcd);
 338                 }
 339         case CL_RECEIVED_PROCEED: /* concat args and send command */
 340                 {
 341                 int i;
 342                 char *command = NULL;
 343                 for (i = 0; i < pcd->conf.inputs_num; i++) {
 344                         char *tmp = command;
 345                         command = make_message("%s\n%s", command?
 346                                 command : "", pcd->conf.inputs[i]);
 347                         free(tmp);
 348                 }
 349                 command = para_strcat(command, EOC_MSG "\n");
 350                 PARA_DEBUG_LOG("--> %s\n", command);
 351                 t->ret = send_buffer(pcd->fd, command);
 352                 free(command);
 353                 if (t->ret > 0)
 354                         pcd->status = CL_SENT_COMMAND;
 355                 return;
 356                 }
 357         case CL_SENT_COMMAND:
 358                 pcd->loaded = 0;
 359                 t->ret = client_recv_buffer(pcd);
 360                 if (t->ret < 0)
 361                         return;
 362                 t->ret = -E_HANDSHAKE_COMPLETE;
 363                 if (strstr(pcd->buf, AWAITING_DATA_MSG))
 364                         pcd->status = CL_SENDING;
 365                 else
 366                         pcd->status = CL_RECEIVING;
 367                 return;
 368         case CL_SENDING: /* FIXME: might block */
 369                 PARA_INFO_LOG("loaded: %zd\n", *pcd->in_loaded);
 370                 t->ret = send_bin_buffer(pcd->fd, pcd->inbuf, *pcd->in_loaded);
 371                 if (t->ret < 0)
 372                         return;
 373                 *pcd->in_loaded = 0;
 374                 return;
 375         case CL_RECEIVING:
 376                 t->ret = client_recv_buffer(pcd);
 377                 return;
 378         }
 379 }