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 pointer that holds the encrypted data after return
  31  * \param private_data pointer to the private client data containing
  32  * the rc4 key
  33  * */
  34 static void rc4_send(unsigned long len, const unsigned char *indata,
  35                 unsigned char *outdata, void *private_data)
  36 {
  37         struct private_client_data *pcd = private_data;
  38         RC4(&pcd->rc4_send_key, len, indata, outdata);
  39 }
  40
  41 /*
  42  * rc4 decrypt received data
  43  *
  44  * \param len the number of bytes to decrypt
  45  * \param indata pointer to the input data of length \a len
  46  * \param outdata pointer that holds the decrypted data after return
  47  * \param private_data pointer to the private client data containing
  48  * the rc4 key
  49  * */
  50 static void rc4_recv(unsigned long len, const unsigned char *indata,
  51                 unsigned char *outdata, void *private_data)
  52 {
  53         struct private_client_data *pcd = private_data;
  54         RC4(&pcd->rc4_recv_key, len, indata, outdata);
  55 }
  56
  57 /**
  58  * close the connection to para_server and free all resources
  59  *
  60  * \param pcd pointer to the client data
  61  *
  62  * \sa client_open.
  63  * */
  64 void client_close(struct private_client_data *pcd)
  65 {
  66         if (!pcd)
  67                 return;
  68         if (pcd->fd >= 0) {
  69                 disable_crypt(pcd->fd);
  70                 close(pcd->fd);
  71         }
  72         free(pcd->user);
  73         free(pcd->config_file);
  74         free(pcd->key_file);
  75         client_cmdline_parser_free(&pcd->conf);
  76         free(pcd);
  77 }
  78
  79 static int client_connect(struct private_client_data *pcd)
  80 {
  81         int ret;
  82         struct hostent *he;
  83         struct sockaddr_in their_addr;
  84
  85         pcd->fd = -1;
  86         ret = get_host_info(pcd->conf.hostname_arg, &he);
  87         if (ret < 0)
  88                 return ret;
  89         /* get new socket */
  90         ret = get_stream_socket(AF_INET);
  91         if (ret < 0)
  92                 return ret;
  93         pcd->fd = ret;
  94         /* init their_addr */
  95         init_sockaddr(&their_addr, pcd->conf.server_port_arg, he);
  96         ret = PARA_CONNECT(pcd->fd, &their_addr);
  97         if (ret < 0)
  98                 goto err_out;
  99         pcd->status = CL_CONNECTED;
 100         ret = mark_fd_nonblock(pcd->fd);
 101         if (ret < 0)
 102                 goto err_out;
 103         pcd->task.pre_select = client_pre_select;
 104         pcd->task.post_select = client_post_select;
 105         pcd->task.private_data = pcd;
 106         sprintf(pcd->task.status, "client");
 107         register_task(&pcd->task);
 108         return 1;
 109 err_out:
 110         close(pcd->fd);
 111         pcd->fd = -1;
 112         return ret;
 113 }
 114
 115 /**
 116  * open connection to para_server
 117  *
 118  * \param argc usual argument count
 119  * \param argv usual argument vector
 120  * \param pcd_ptr points to dynamically allocated and initialized private client data
 121  * upon successful return
 122  *
 123  * Check the command line options given by \a argc and argv, set default values
 124  * for user name and rsa key file, read further option from the config file.
 125  * Finally, establish a connection to para_server.
 126  *
 127  * \return Positive on success, negative on errors.
 128  */
 129 int client_open(int argc, char *argv[], struct private_client_data **pcd_ptr)
 130 {
 131         char *home = para_homedir();
 132         struct stat statbuf;
 133         int ret;
 134         struct private_client_data *pcd =
 135                 para_calloc(sizeof(struct private_client_data));
 136
 137         *pcd_ptr = pcd;
 138         pcd->fd = -1;
 139         ret = client_cmdline_parser(argc, argv, &pcd->conf);
 140         HANDLE_VERSION_FLAG("client", pcd->conf);
 141         ret = -E_CLIENT_SYNTAX;
 142         if (!pcd->conf.inputs_num)
 143                 goto out;
 144         pcd->user = pcd->conf.user_given?
 145                 para_strdup(pcd->conf.user_arg) : para_logname();
 146
 147         pcd->key_file = pcd->conf.key_file_given?
 148                 para_strdup(pcd->conf.key_file_arg) :
 149                 make_message("%s/.paraslash/key.%s", home, pcd->user);
 150
 151         pcd->config_file = pcd->conf.config_file_given?
 152                 para_strdup(pcd->conf.config_file_arg) :
 153                 make_message("%s/.paraslash/client.conf", home);
 154         ret = stat(pcd->config_file, &statbuf);
 155         if (ret && pcd->conf.config_file_given) {
 156                 ret = -E_NO_CONFIG;
 157                 goto out;
 158         }
 159         if (!ret) {
 160                 struct client_cmdline_parser_params params = {
 161                         .override = 0,
 162                         .initialize = 0,
 163                         .check_required = 0,
 164                         .check_ambiguity = 0
 165                 };
 166                 client_cmdline_parser_config_file(pcd->config_file,
 167                         &pcd->conf, &params);
 168         }
 169         ret = 1;
 170         PARA_INFO_LOG("loglevel: %d\n", pcd->conf.loglevel_arg);
 171         PARA_INFO_LOG("config_file: %s\n", pcd->config_file);
 172         PARA_INFO_LOG("key_file: %s\n", pcd->key_file);
 173         PARA_NOTICE_LOG("connecting %s:%d\n", pcd->conf.hostname_arg,
 174                 pcd->conf.server_port_arg);
 175         ret = client_connect(pcd);
 176 out:
 177         free(home);
 178         if (ret < 0) {
 179                 PARA_ERROR_LOG("%s\n", PARA_STRERROR(-ret));
 180                 client_close(pcd);
 181                 *pcd_ptr = NULL;
 182         }
 183         return ret;
 184 }
 185
 186 /**
 187  * the preselect hook for server commands
 188  *
 189  * \param s pointer to the scheduler
 190  * \param t pointer to the task struct for this command
 191  *
 192  * The task pointer must contain a pointer to the initialized client data
 193  * structure as it is returned by client_open().
 194  *
 195  * This function checks the state of the connection and adds the file descriptor
 196  * of the connection to the read or write fd set of \a s accordingly.
 197  *
 198  * \sa register_task() client_open(), struct sched, struct task
 199  */
 200 void client_pre_select(struct sched *s, struct task *t)
 201 {
 202         struct private_client_data *pcd = t->private_data;
 203
 204         t->ret = 1;
 205         pcd->check_r = 0;
 206         pcd->check_w = 0;
 207         if (pcd->fd < 0)
 208                 return;
 209         switch (pcd->status) {
 210         case CL_CONNECTED:
 211         case CL_SENT_AUTH:
 212         case CL_SENT_CH_RESPONSE:
 213         case CL_SENT_COMMAND:
 214                 para_fd_set(pcd->fd, &s->rfds, &s->max_fileno);
 215                 pcd->check_r = 1;
 216                 return;
 217
 218         case CL_RECEIVED_WELCOME:
 219         case CL_RECEIVED_CHALLENGE:
 220         case CL_RECEIVED_PROCEED:
 221                 para_fd_set(pcd->fd, &s->wfds, &s->max_fileno);
 222                 pcd->check_w = 1;
 223                 return;
 224
 225         case CL_RECEIVING:
 226                 if (pcd->loaded < CLIENT_BUFSIZE - 1) {
 227                         para_fd_set(pcd->fd, &s->rfds, &s->max_fileno);
 228                         pcd->check_r = 1;
 229                 }
 230                 return;
 231         case CL_SENDING:
 232                 if (*pcd->in_loaded) {
 233                         PARA_INFO_LOG("loaded: %zd\n", *pcd->in_loaded);
 234                         para_fd_set(pcd->fd, &s->wfds, &s->max_fileno);
 235                         pcd->check_w = 1;
 236                 } else {
 237                         if (*pcd->in_eof) {
 238                                 t->ret = -E_INPUT_EOF;
 239                                 s->timeout.tv_sec = 0;
 240                                 s->timeout.tv_usec = 1;
 241                         }
 242                 }
 243                 return;
 244         }
 245 }
 246
 247 static ssize_t client_recv_buffer(struct private_client_data *pcd)
 248 {
 249         ssize_t ret = recv_buffer(pcd->fd, pcd->buf + pcd->loaded,
 250                 CLIENT_BUFSIZE - pcd->loaded);
 251         if (!ret)
 252                 return -E_SERVER_EOF;
 253         if (ret > 0)
 254                 pcd->loaded += ret;
 255         return ret;
 256
 257 }
 258
 259 /**
 260  * the post select hook for client commands
 261  *
 262  * \param s pointer to the scheduler
 263  * \param t pointer to the task struct for this command
 264  *
 265  * Depending on the current state of the connection and the status of the read
 266  * and write fd sets of \a s, this function performs the necessary steps to
 267  * authenticate the connection, to send the command given by \a
 268  * t->private_data and to receive para_server's output, if any.
 269  *
 270  * \sa struct sched, struct task
 271  */
 272 void client_post_select(struct sched *s, struct task *t)
 273 {
 274         struct private_client_data *pcd = t->private_data;
 275
 276 //      PARA_INFO_LOG("status %d\n", pcd->status);
 277         t->ret = 1;
 278         if (pcd->fd < 0)
 279                 return;
 280         if (!pcd->check_r && !pcd->check_w)
 281                 return;
 282         if (pcd->check_r && !FD_ISSET(pcd->fd, &s->rfds))
 283                 return;
 284         if (pcd->check_w && !FD_ISSET(pcd->fd, &s->wfds))
 285                 return;
 286         switch (pcd->status) {
 287         case CL_CONNECTED: /* receive welcome message */
 288                 t->ret = client_recv_buffer(pcd);
 289                 if (t->ret > 0)
 290                         pcd->status = CL_RECEIVED_WELCOME;
 291                 return;
 292         case CL_RECEIVED_WELCOME: /* send auth command */
 293                 sprintf(pcd->buf, "auth %s%s", pcd->conf.plain_given?
 294                         "" : "rc4 ", pcd->user);
 295                 PARA_INFO_LOG("--> %s\n", pcd->buf);
 296                 t->ret = send_buffer(pcd->fd, pcd->buf);
 297                 if (t->ret >= 0)
 298                         pcd->status = CL_SENT_AUTH;
 299                 return;
 300         case CL_SENT_AUTH: /* receive challenge number */
 301                 pcd->loaded = 0;
 302                 t->ret = client_recv_buffer(pcd);
 303                 if (t->ret < 0)
 304                         return;
 305                 if (t->ret != 64) {
 306                         t->ret = -E_INVALID_CHALLENGE;
 307                         PARA_ERROR_LOG("received the following: %s\n", pcd->buf);
 308                         return;
 309                 }
 310                 PARA_INFO_LOG("%s", "<-- [challenge]\n");
 311                 /* decrypt challenge number */
 312                 t->ret = para_decrypt_challenge(pcd->key_file, &pcd->challenge_nr,
 313                         (unsigned char *) pcd->buf, 64);
 314                 if (t->ret > 0)
 315                         pcd->status = CL_RECEIVED_CHALLENGE;
 316                 return;
 317         case CL_RECEIVED_CHALLENGE: /* send decrypted challenge */
 318                 PARA_INFO_LOG("--> %lu\n", pcd->challenge_nr);
 319                 t->ret = send_va_buffer(pcd->fd, "%s%lu", CHALLENGE_RESPONSE_MSG,
 320                         pcd->challenge_nr);
 321                 if (t->ret > 0)
 322                         pcd->status = CL_SENT_CH_RESPONSE;
 323                 return;
 324         case CL_SENT_CH_RESPONSE: /* read server response */
 325                 {
 326                 size_t bytes_received;
 327                 unsigned char rc4_buf[2 * RC4_KEY_LEN] = "";
 328                 pcd->loaded = 0;
 329                 t->ret = client_recv_buffer(pcd);
 330                 if (t->ret < 0)
 331                         return;
 332                 bytes_received = t->ret;
 333                 PARA_DEBUG_LOG("++++ server info ++++\n%s\n++++ end of server "
 334                         "info ++++\n", pcd->buf);
 335                 /* check if server has sent "Proceed" message */
 336                 t->ret = -E_CLIENT_AUTH;
 337                 if (!strstr(pcd->buf, PROCEED_MSG))
 338                         return;
 339                 t->ret = 1;
 340                 pcd->status = CL_RECEIVED_PROCEED;
 341                 if (bytes_received < PROCEED_MSG_LEN + 32)
 342                         return;
 343                 PARA_INFO_LOG("%s", "decrypting session key\n");
 344                 t->ret = para_decrypt_buffer(pcd->key_file, rc4_buf,
 345                         (unsigned char *)pcd->buf + PROCEED_MSG_LEN + 1,
 346                         bytes_received - PROCEED_MSG_LEN - 1);
 347                 if (t->ret < 0)
 348                         return;
 349                 RC4_set_key(&pcd->rc4_send_key, RC4_KEY_LEN, rc4_buf);
 350                 RC4_set_key(&pcd->rc4_recv_key, RC4_KEY_LEN, rc4_buf + RC4_KEY_LEN);
 351                 enable_crypt(pcd->fd, rc4_recv, rc4_send, pcd);
 352                 }
 353         case CL_RECEIVED_PROCEED: /* concat args and send command */
 354                 {
 355                 int i;
 356                 char *command = NULL;
 357                 for (i = 0; i < pcd->conf.inputs_num; i++) {
 358                         char *tmp = command;
 359                         command = make_message("%s\n%s", command?
 360                                 command : "", pcd->conf.inputs[i]);
 361                         free(tmp);
 362                 }
 363                 command = para_strcat(command, EOC_MSG "\n");
 364                 PARA_DEBUG_LOG("--> %s\n", command);
 365                 t->ret = send_buffer(pcd->fd, command);
 366                 free(command);
 367                 if (t->ret > 0)
 368                         pcd->status = CL_SENT_COMMAND;
 369                 return;
 370                 }
 371         case CL_SENT_COMMAND:
 372                 pcd->loaded = 0;
 373                 t->ret = client_recv_buffer(pcd);
 374                 if (t->ret < 0)
 375                         return;
 376                 t->ret = -E_HANDSHAKE_COMPLETE;
 377                 if (strstr(pcd->buf, AWAITING_DATA_MSG))
 378                         pcd->status = CL_SENDING;
 379                 else
 380                         pcd->status = CL_RECEIVING;
 381                 return;
 382         case CL_SENDING: /* FIXME: might block */
 383                 PARA_INFO_LOG("loaded: %zd\n", *pcd->in_loaded);
 384                 t->ret = send_bin_buffer(pcd->fd, pcd->inbuf, *pcd->in_loaded);
 385                 if (t->ret < 0)
 386                         return;
 387                 *pcd->in_loaded = 0; /* FIXME: short writes */
 388                 return;
 389         case CL_RECEIVING:
 390                 t->ret = client_recv_buffer(pcd);
 391                 return;
 392         }
 393 }