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