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