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