client_common.c

   1 /*
   2  * Copyright (C) 1997-2009 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->buf);
  68         free(ct->user);
  69         free(ct->config_file);
  70         free(ct->key_file);
  71         client_cmdline_parser_free(&ct->conf);
  72         free(ct);
  73 }
  74
  75 /**
  76  * The preselect hook for server commands.
  77  *
  78  * \param s Pointer to the scheduler.
  79  * \param t Pointer to the task struct for this command.
  80  *
  81  * The task pointer must contain a pointer to the initialized client data
  82  * structure as it is returned by client_open().
  83  *
  84  * This function checks the state of the connection and adds the file descriptor
  85  * of the connection to the read or write fd set of \a s accordingly.
  86  *
  87  * \sa register_task() client_open(), struct sched, struct task.
  88  */
  89 static void client_pre_select(struct sched *s, struct task *t)
  90 {
  91         struct client_task *ct = container_of(t, struct client_task, task);
  92
  93         ct->check_r = 0;
  94         ct->check_w = 0;
  95         if (ct->fd < 0)
  96                 return;
  97         switch (ct->status) {
  98         case CL_CONNECTED:
  99         case CL_SENT_AUTH:
 100         case CL_SENT_CH_RESPONSE:
 101         case CL_SENT_COMMAND:
 102                 para_fd_set(ct->fd, &s->rfds, &s->max_fileno);
 103                 ct->check_r = 1;
 104                 return;
 105
 106         case CL_RECEIVED_WELCOME:
 107         case CL_RECEIVED_CHALLENGE:
 108         case CL_RECEIVED_PROCEED:
 109                 para_fd_set(ct->fd, &s->wfds, &s->max_fileno);
 110                 ct->check_w = 1;
 111                 return;
 112
 113         case CL_RECEIVING:
 114                 if (ct->loaded < CLIENT_BUFSIZE - 1) {
 115                         para_fd_set(ct->fd, &s->rfds, &s->max_fileno);
 116                         ct->check_r = 1;
 117                 }
 118                 return;
 119         case CL_SENDING:
 120                 if (!ct->in_loaded) /* stdin task not yet started */
 121                         return;
 122                 if (*ct->in_loaded) {
 123                         PARA_INFO_LOG("loaded: %zd\n", *ct->in_loaded);
 124                         para_fd_set(ct->fd, &s->wfds, &s->max_fileno);
 125                         ct->check_w = 1;
 126                 } else {
 127                         if (*ct->in_error) {
 128                                 t->error = *ct->in_error;
 129                                 s->timeout.tv_sec = 0;
 130                                 s->timeout.tv_usec = 1;
 131                         }
 132                 }
 133                 return;
 134         }
 135 }
 136
 137 static ssize_t client_recv_buffer(struct client_task *ct)
 138 {
 139         ssize_t ret = recv_buffer(ct->fd, ct->buf + ct->loaded,
 140                 CLIENT_BUFSIZE - ct->loaded);
 141         if (!ret)
 142                 return -E_SERVER_EOF;
 143         if (ret > 0)
 144                 ct->loaded += ret;
 145         return ret;
 146
 147 }
 148
 149 /**
 150  * The post select hook for client commands.
 151  *
 152  * \param s Pointer to the scheduler.
 153  * \param t Pointer to the task struct for this command.
 154  *
 155  * Depending on the current state of the connection and the status of the read
 156  * and write fd sets of \a s, this function performs the necessary steps to
 157  * authenticate the connection, to send the command given by \a t->private_data
 158  * and to receive para_server's output, if any.
 159  *
 160  * \sa struct sched, struct task.
 161  */
 162 static void client_post_select(struct sched *s, struct task *t)
 163 {
 164         struct client_task *ct = container_of(t, struct client_task, task);
 165
 166         t->error = 0;
 167         if (ct->fd < 0)
 168                 return;
 169         if (!ct->check_r && !ct->check_w)
 170                 return;
 171         if (ct->check_r && !FD_ISSET(ct->fd, &s->rfds))
 172                 return;
 173         if (ct->check_w && !FD_ISSET(ct->fd, &s->wfds))
 174                 return;
 175         switch (ct->status) {
 176         case CL_CONNECTED: /* receive welcome message */
 177                 t->error = client_recv_buffer(ct);
 178                 if (t->error > 0)
 179                         ct->status = CL_RECEIVED_WELCOME;
 180                 return;
 181         case CL_RECEIVED_WELCOME: /* send auth command */
 182                 sprintf(ct->buf, "auth %s%s", ct->conf.plain_given?
 183                         "" : "rc4 ", ct->user);
 184                 PARA_INFO_LOG("--> %s\n", ct->buf);
 185                 t->error = send_buffer(ct->fd, ct->buf);
 186                 if (t->error >= 0)
 187                         ct->status = CL_SENT_AUTH;
 188                 return;
 189         case CL_SENT_AUTH: /* receive challenge number */
 190                 ct->loaded = 0;
 191                 t->error = client_recv_buffer(ct);
 192                 if (t->error < 0)
 193                         return;
 194                 if (t->error < 64) {
 195                         t->error = -E_INVALID_CHALLENGE;
 196                         PARA_ERROR_LOG("received the following: %s\n", ct->buf);
 197                         return;
 198                 }
 199                 PARA_INFO_LOG("<-- [challenge] (%d bytes)\n", t->error);
 200                 /* decrypt challenge number */
 201                 t->error = para_decrypt_challenge(ct->key_file, &ct->challenge_nr,
 202                         (unsigned char *) ct->buf, t->error);
 203                 if (t->error > 0)
 204                         ct->status = CL_RECEIVED_CHALLENGE;
 205                 return;
 206         case CL_RECEIVED_CHALLENGE: /* send decrypted challenge */
 207                 PARA_INFO_LOG("--> %lu\n", ct->challenge_nr);
 208                 t->error = send_va_buffer(ct->fd, "%s%lu", CHALLENGE_RESPONSE_MSG,
 209                         ct->challenge_nr);
 210                 if (t->error > 0)
 211                         ct->status = CL_SENT_CH_RESPONSE;
 212                 return;
 213         case CL_SENT_CH_RESPONSE: /* read server response */
 214                 {
 215                 size_t bytes_received;
 216                 unsigned char rc4_buf[2 * RC4_KEY_LEN] = "";
 217                 ct->loaded = 0;
 218                 t->error = client_recv_buffer(ct);
 219                 if (t->error < 0)
 220                         return;
 221                 bytes_received = t->error;
 222                 PARA_DEBUG_LOG("++++ server info ++++\n%s\n++++ end of server "
 223                         "info ++++\n", ct->buf);
 224                 /* check if server has sent "Proceed" message */
 225                 t->error = -E_CLIENT_AUTH;
 226                 if (!strstr(ct->buf, PROCEED_MSG))
 227                         return;
 228                 t->error = 0;
 229                 ct->status = CL_RECEIVED_PROCEED;
 230                 if (bytes_received < PROCEED_MSG_LEN + 32)
 231                         return;
 232                 PARA_INFO_LOG("decrypting session key\n");
 233                 t->error = para_decrypt_buffer(ct->key_file, rc4_buf,
 234                         (unsigned char *)ct->buf + PROCEED_MSG_LEN + 1,
 235                         bytes_received - PROCEED_MSG_LEN - 1);
 236                 if (t->error < 0)
 237                         return;
 238                 RC4_set_key(&ct->rc4_send_key, RC4_KEY_LEN, rc4_buf);
 239                 RC4_set_key(&ct->rc4_recv_key, RC4_KEY_LEN, rc4_buf + RC4_KEY_LEN);
 240                 enable_crypt(ct->fd, rc4_recv, rc4_send, ct);
 241                 }
 242         case CL_RECEIVED_PROCEED: /* concat args and send command */
 243                 {
 244                 int i;
 245                 char *command = NULL;
 246                 for (i = 0; i < ct->conf.inputs_num; i++) {
 247                         char *tmp = command;
 248                         command = make_message("%s\n%s", command?
 249                                 command : "", ct->conf.inputs[i]);
 250                         free(tmp);
 251                 }
 252                 command = para_strcat(command, EOC_MSG "\n");
 253                 PARA_DEBUG_LOG("--> %s\n", command);
 254                 t->error = send_buffer(ct->fd, command);
 255                 free(command);
 256                 if (t->error > 0)
 257                         ct->status = CL_SENT_COMMAND;
 258                 return;
 259                 }
 260         case CL_SENT_COMMAND:
 261                 ct->loaded = 0;
 262                 t->error = client_recv_buffer(ct);
 263                 if (t->error < 0)
 264                         return;
 265                 if (strstr(ct->buf, AWAITING_DATA_MSG))
 266                         ct->status = CL_SENDING;
 267                 else
 268                         ct->status = CL_RECEIVING;
 269                 return;
 270         case CL_SENDING: /* FIXME: might block */
 271                 PARA_INFO_LOG("loaded: %zd\n", *ct->in_loaded);
 272                 t->error = send_bin_buffer(ct->fd, ct->inbuf, *ct->in_loaded);
 273                 if (t->error < 0)
 274                         return;
 275                 *ct->in_loaded = 0;
 276                 return;
 277         case CL_RECEIVING:
 278                 t->error = client_recv_buffer(ct);
 279                 return;
 280         }
 281 }
 282
 283 /* connect to para_server and register the client task */
 284 static int client_connect(struct client_task *ct)
 285 {
 286         int ret;
 287
 288         ct->fd = -1;
 289         ret = makesock(AF_UNSPEC, IPPROTO_TCP, 0, ct->conf.hostname_arg,
 290                 ct->conf.server_port_arg);
 291         if (ret < 0)
 292                 return ret;
 293         ct->fd = ret;
 294         ct->status = CL_CONNECTED;
 295         ret = mark_fd_nonblocking(ct->fd);
 296         if (ret < 0)
 297                 goto err_out;
 298         ct->task.pre_select = client_pre_select;
 299         ct->task.post_select = client_post_select;
 300         sprintf(ct->task.status, "client");
 301         register_task(&ct->task);
 302         return 1;
 303 err_out:
 304         close(ct->fd);
 305         ct->fd = -1;
 306         return ret;
 307 }
 308
 309 /**
 310  * Open connection to para_server.
 311  *
 312  * \param argc Usual argument count.
 313  * \param argv Usual argument vector.
 314  * \param ct_ptr Points to dynamically allocated and initialized client task
 315  * struct upon successful return.
 316  * \param loglevel If not \p NULL, the number of the loglevel is stored here.
 317  *
 318  * Check the command line options given by \a argc and argv, set default values
 319  * for user name and rsa key file, read further option from the config file.
 320  * Finally, establish a connection to para_server.
 321  *
 322  * \return Standard.
 323  */
 324 int client_open(int argc, char *argv[], struct client_task **ct_ptr,
 325                 int *loglevel)
 326 {
 327         char *home = para_homedir();
 328         int ret;
 329         struct client_task *ct = para_calloc(sizeof(struct client_task));
 330
 331         ct->buf = para_malloc(CLIENT_BUFSIZE);
 332         *ct_ptr = ct;
 333         ct->fd = -1;
 334         ret = -E_CLIENT_SYNTAX;
 335         if (client_cmdline_parser(argc, argv, &ct->conf))
 336                 goto out;
 337         HANDLE_VERSION_FLAG("client", ct->conf);
 338         ret = -E_CLIENT_SYNTAX;
 339         if (!ct->conf.inputs_num)
 340                 goto out;
 341         ct->user = ct->conf.user_given?
 342                 para_strdup(ct->conf.user_arg) : para_logname();
 343
 344         ct->key_file = ct->conf.key_file_given?
 345                 para_strdup(ct->conf.key_file_arg) :
 346                 make_message("%s/.paraslash/key.%s", home, ct->user);
 347
 348         ct->config_file = ct->conf.config_file_given?
 349                 para_strdup(ct->conf.config_file_arg) :
 350                 make_message("%s/.paraslash/client.conf", home);
 351         ret = file_exists(ct->config_file);
 352         if (!ret && ct->conf.config_file_given) {
 353                 ret = -E_NO_CONFIG;
 354                 goto out;
 355         }
 356         if (ret) {
 357                 struct client_cmdline_parser_params params = {
 358                         .override = 0,
 359                         .initialize = 0,
 360                         .check_required = 0,
 361                         .check_ambiguity = 0,
 362                         .print_errors = 0
 363                 };
 364                 ret = -E_BAD_CONFIG;
 365                 if (client_cmdline_parser_config_file(ct->config_file,
 366                         &ct->conf, &params))
 367                         goto out;
 368         }
 369         if (loglevel)
 370                 *loglevel = get_loglevel_by_name(ct->conf.loglevel_arg);
 371         PARA_INFO_LOG("loglevel: %s\n", ct->conf.loglevel_arg);
 372         PARA_INFO_LOG("config_file: %s\n", ct->config_file);
 373         PARA_INFO_LOG("key_file: %s\n", ct->key_file);
 374         PARA_NOTICE_LOG("connecting %s:%d\n", ct->conf.hostname_arg,
 375                 ct->conf.server_port_arg);
 376         ret = client_connect(ct);
 377 out:
 378         free(home);
 379         if (ret < 0) {
 380                 PARA_ERROR_LOG("%s\n", para_strerror(-ret));
 381                 client_close(ct);
 382                 *ct_ptr = NULL;
 383         }
 384         return ret;
 385 }