client_common.c

   1 /*
   2  * Copyright (C) 1997-2008 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 client_task *ct = private_data;
  37         RC4(&ct->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 client_task *ct = private_data;
  49         RC4(&ct->rc4_recv_key, len, indata, outdata);
  50 }
  51
  52 /**
  53  * Close the connection to para_server and free all resources.
  54  *
  55  * \param ct Pointer to the client data.
  56  *
  57  * \sa client_open.
  58  */
  59 void client_close(struct client_task *ct)
  60 {
  61         if (!ct)
  62                 return;
  63         if (ct->fd >= 0) {
  64                 disable_crypt(ct->fd);
  65                 close(ct->fd);
  66         }
  67         free(ct->user);
  68         free(ct->config_file);
  69         free(ct->key_file);
  70         client_cmdline_parser_free(&ct->conf);
  71         free(ct);
  72 }
  73
  74 /**
  75  * The preselect hook for server commands.
  76  *
  77  * \param s Pointer to the scheduler.
  78  * \param t Pointer to the task struct for this command.
  79  *
  80  * The task pointer must contain a pointer to the initialized client data
  81  * structure as it is returned by client_open().
  82  *
  83  * This function checks the state of the connection and adds the file descriptor
  84  * of the connection to the read or write fd set of \a s accordingly.
  85  *
  86  * \sa register_task() client_open(), struct sched, struct task.
  87  */
  88 static void client_pre_select(struct sched *s, struct task *t)
  89 {
  90         struct client_task *ct = container_of(t, struct client_task, task);
  91
  92         ct->check_r = 0;
  93         ct->check_w = 0;
  94         if (ct->fd < 0)
  95                 return;
  96         switch (ct->status) {
  97         case CL_CONNECTED:
  98         case CL_SENT_AUTH:
  99         case CL_SENT_CH_RESPONSE:
 100         case CL_SENT_COMMAND:
 101                 para_fd_set(ct->fd, &s->rfds, &s->max_fileno);
 102                 ct->check_r = 1;
 103                 return;
 104
 105         case CL_RECEIVED_WELCOME:
 106         case CL_RECEIVED_CHALLENGE:
 107         case CL_RECEIVED_PROCEED:
 108                 para_fd_set(ct->fd, &s->wfds, &s->max_fileno);
 109                 ct->check_w = 1;
 110                 return;
 111
 112         case CL_RECEIVING:
 113                 if (ct->loaded < CLIENT_BUFSIZE - 1) {
 114                         para_fd_set(ct->fd, &s->rfds, &s->max_fileno);
 115                         ct->check_r = 1;
 116                 }
 117                 return;
 118         case CL_SENDING:
 119                 if (!ct->in_loaded) /* stdin task not yet started */
 120                         return;
 121                 if (*ct->in_loaded) {
 122                         PARA_INFO_LOG("loaded: %zd\n", *ct->in_loaded);
 123                         para_fd_set(ct->fd, &s->wfds, &s->max_fileno);
 124                         ct->check_w = 1;
 125                 } else {
 126                         if (*ct->in_error) {
 127                                 t->error = *ct->in_error;
 128                                 s->timeout.tv_sec = 0;
 129                                 s->timeout.tv_usec = 1;
 130                         }
 131                 }
 132                 return;
 133         }
 134 }
 135
 136 static ssize_t client_recv_buffer(struct client_task *ct)
 137 {
 138         ssize_t ret = recv_buffer(ct->fd, ct->buf + ct->loaded,
 139                 CLIENT_BUFSIZE - ct->loaded);
 140         if (!ret)
 141                 return -E_SERVER_EOF;
 142         if (ret > 0)
 143                 ct->loaded += ret;
 144         return ret;
 145
 146 }
 147
 148 /**
 149  * The post select hook for client commands.
 150  *
 151  * \param s Pointer to the scheduler.
 152  * \param t Pointer to the task struct for this command.
 153  *
 154  * Depending on the current state of the connection and the status of the read
 155  * and write fd sets of \a s, this function performs the necessary steps to
 156  * authenticate the connection, to send the command given by \a t->private_data
 157  * and to receive para_server's output, if any.
 158  *
 159  * \sa struct sched, struct task.
 160  */
 161 static void client_post_select(struct sched *s, struct task *t)
 162 {
 163         struct client_task *ct = container_of(t, struct client_task, task);
 164
 165         t->error = 0;
 166         if (ct->fd < 0)
 167                 return;
 168         if (!ct->check_r && !ct->check_w)
 169                 return;
 170         if (ct->check_r && !FD_ISSET(ct->fd, &s->rfds))
 171                 return;
 172         if (ct->check_w && !FD_ISSET(ct->fd, &s->wfds))
 173                 return;
 174         switch (ct->status) {
 175         case CL_CONNECTED: /* receive welcome message */
 176                 t->error = client_recv_buffer(ct);
 177                 if (t->error > 0)
 178                         ct->status = CL_RECEIVED_WELCOME;
 179                 return;
 180         case CL_RECEIVED_WELCOME: /* send auth command */
 181                 sprintf(ct->buf, "auth %s%s", ct->conf.plain_given?
 182                         "" : "rc4 ", ct->user);
 183                 PARA_INFO_LOG("--> %s\n", ct->buf);
 184                 t->error = send_buffer(ct->fd, ct->buf);
 185                 if (t->error >= 0)
 186                         ct->status = CL_SENT_AUTH;
 187                 return;
 188         case CL_SENT_AUTH: /* receive challenge number */
 189                 ct->loaded = 0;
 190                 t->error = client_recv_buffer(ct);
 191                 if (t->error < 0)
 192                         return;
 193                 if (t->error != 64) {
 194                         t->error = -E_INVALID_CHALLENGE;
 195                         PARA_ERROR_LOG("received the following: %s\n", ct->buf);
 196                         return;
 197                 }
 198                 PARA_INFO_LOG("<-- [challenge]\n");
 199                 /* decrypt challenge number */
 200                 t->error = para_decrypt_challenge(ct->key_file, &ct->challenge_nr,
 201                         (unsigned char *) ct->buf, 64);
 202                 if (t->error > 0)
 203                         ct->status = CL_RECEIVED_CHALLENGE;
 204                 return;
 205         case CL_RECEIVED_CHALLENGE: /* send decrypted challenge */
 206                 PARA_INFO_LOG("--> %lu\n", ct->challenge_nr);
 207                 t->error = send_va_buffer(ct->fd, "%s%lu", CHALLENGE_RESPONSE_MSG,
 208                         ct->challenge_nr);
 209                 if (t->error > 0)
 210                         ct->status = CL_SENT_CH_RESPONSE;
 211                 return;
 212         case CL_SENT_CH_RESPONSE: /* read server response */
 213                 {
 214                 size_t bytes_received;
 215                 unsigned char rc4_buf[2 * RC4_KEY_LEN] = "";
 216                 ct->loaded = 0;
 217                 t->error = client_recv_buffer(ct);
 218                 if (t->error < 0)
 219                         return;
 220                 bytes_received = t->error;
 221                 PARA_DEBUG_LOG("++++ server info ++++\n%s\n++++ end of server "
 222                         "info ++++\n", ct->buf);
 223                 /* check if server has sent "Proceed" message */
 224                 t->error = -E_CLIENT_AUTH;
 225                 if (!strstr(ct->buf, PROCEED_MSG))
 226                         return;
 227                 t->error = 0;
 228                 ct->status = CL_RECEIVED_PROCEED;
 229                 if (bytes_received < PROCEED_MSG_LEN + 32)
 230                         return;
 231                 PARA_INFO_LOG("decrypting session key\n");
 232                 t->error = para_decrypt_buffer(ct->key_file, rc4_buf,
 233                         (unsigned char *)ct->buf + PROCEED_MSG_LEN + 1,
 234                         bytes_received - PROCEED_MSG_LEN - 1);
 235                 if (t->error < 0)
 236                         return;
 237                 RC4_set_key(&ct->rc4_send_key, RC4_KEY_LEN, rc4_buf);
 238                 RC4_set_key(&ct->rc4_recv_key, RC4_KEY_LEN, rc4_buf + RC4_KEY_LEN);
 239                 enable_crypt(ct->fd, rc4_recv, rc4_send, ct);
 240                 }
 241         case CL_RECEIVED_PROCEED: /* concat args and send command */
 242                 {
 243                 int i;
 244                 char *command = NULL;
 245                 for (i = 0; i < ct->conf.inputs_num; i++) {
 246                         char *tmp = command;
 247                         command = make_message("%s\n%s", command?
 248                                 command : "", ct->conf.inputs[i]);
 249                         free(tmp);
 250                 }
 251                 command = para_strcat(command, EOC_MSG "\n");
 252                 PARA_DEBUG_LOG("--> %s\n", command);
 253                 t->error = send_buffer(ct->fd, command);
 254                 free(command);
 255                 if (t->error > 0)
 256                         ct->status = CL_SENT_COMMAND;
 257                 return;
 258                 }
 259         case CL_SENT_COMMAND:
 260                 ct->loaded = 0;
 261                 t->error = client_recv_buffer(ct);
 262                 if (t->error < 0)
 263                         return;
 264                 if (strstr(ct->buf, AWAITING_DATA_MSG))
 265                         ct->status = CL_SENDING;
 266                 else
 267                         ct->status = CL_RECEIVING;
 268                 return;
 269         case CL_SENDING: /* FIXME: might block */
 270                 PARA_INFO_LOG("loaded: %zd\n", *ct->in_loaded);
 271                 t->error = send_bin_buffer(ct->fd, ct->inbuf, *ct->in_loaded);
 272                 if (t->error < 0)
 273                         return;
 274                 *ct->in_loaded = 0;
 275                 return;
 276         case CL_RECEIVING:
 277                 t->error = client_recv_buffer(ct);
 278                 return;
 279         }
 280 }
 281
 282 /* connect to para_server and register the client task */
 283 static int client_connect(struct client_task *ct)
 284 {
 285         int ret;
 286
 287         ct->fd = -1;
 288         ret = makesock(AF_UNSPEC, IPPROTO_TCP, 0, ct->conf.hostname_arg,
 289                 ct->conf.server_port_arg);
 290         if (ret < 0)
 291                 return ret;
 292         ct->fd = ret;
 293         ct->status = CL_CONNECTED;
 294         ret = mark_fd_nonblocking(ct->fd);
 295         if (ret < 0)
 296                 goto err_out;
 297         ct->task.pre_select = client_pre_select;
 298         ct->task.post_select = client_post_select;
 299         sprintf(ct->task.status, "client");
 300         register_task(&ct->task);
 301         return 1;
 302 err_out:
 303         close(ct->fd);
 304         ct->fd = -1;
 305         return ret;
 306 }
 307
 308 /**
 309  * Open connection to para_server.
 310  *
 311  * \param argc Usual argument count.
 312  * \param argv Usual argument vector.
 313  * \param ct_ptr Points to dynamically allocated and initialized client task
 314  * struct upon successful return.
 315  *
 316  * Check the command line options given by \a argc and argv, set default values
 317  * for user name and rsa key file, read further option from the config file.
 318  * Finally, establish a connection to para_server.
 319  *
 320  * \return Standard.
 321  */
 322 int client_open(int argc, char *argv[], struct client_task **ct_ptr)
 323 {
 324         char *home = para_homedir();
 325         struct stat statbuf;
 326         int ret;
 327         struct client_task *ct = para_calloc(sizeof(struct client_task));
 328
 329         *ct_ptr = ct;
 330         ct->fd = -1;
 331         ret = -E_CLIENT_SYNTAX;
 332         if (client_cmdline_parser(argc, argv, &ct->conf))
 333                 goto out;
 334         HANDLE_VERSION_FLAG("client", ct->conf);
 335         ret = -E_CLIENT_SYNTAX;
 336         if (!ct->conf.inputs_num)
 337                 goto out;
 338         ct->user = ct->conf.user_given?
 339                 para_strdup(ct->conf.user_arg) : para_logname();
 340
 341         ct->key_file = ct->conf.key_file_given?
 342                 para_strdup(ct->conf.key_file_arg) :
 343                 make_message("%s/.paraslash/key.%s", home, ct->user);
 344
 345         ct->config_file = ct->conf.config_file_given?
 346                 para_strdup(ct->conf.config_file_arg) :
 347                 make_message("%s/.paraslash/client.conf", home);
 348         ret = stat(ct->config_file, &statbuf);
 349         if (ret && ct->conf.config_file_given) {
 350                 ret = -E_NO_CONFIG;
 351                 goto out;
 352         }
 353         if (!ret) {
 354                 struct client_cmdline_parser_params params = {
 355                         .override = 0,
 356                         .initialize = 0,
 357                         .check_required = 0,
 358                         .check_ambiguity = 0,
 359                         .print_errors = 0
 360                 };
 361                 ret = -E_BAD_CONFIG;
 362                 if (client_cmdline_parser_config_file(ct->config_file,
 363                         &ct->conf, &params))
 364                         goto out;
 365         }
 366         ret = 1;
 367         PARA_INFO_LOG("loglevel: %d\n", ct->conf.loglevel_arg);
 368         PARA_INFO_LOG("config_file: %s\n", ct->config_file);
 369         PARA_INFO_LOG("key_file: %s\n", ct->key_file);
 370         PARA_NOTICE_LOG("connecting %s:%d\n", ct->conf.hostname_arg,
 371                 ct->conf.server_port_arg);
 372         ret = client_connect(ct);
 373 out:
 374         free(home);
 375         if (ret < 0) {
 376                 PARA_ERROR_LOG("%s\n", para_strerror(-ret));
 377                 client_close(ct);
 378                 *ct_ptr = NULL;
 379         }
 380         return ret;
 381 }