src/network.c

   1 /* $Id$
   2  * UDP Gateway utility network layer
   3  * Copyright (C) 2004 Jan Kratochvil <project-udpgate@jankratochvil.net>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; exactly version 2 of June 1991 is required
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  17  */
  18
  19
  20 #include "config.h"
  21
  22 #include <glib/gmessages.h>
  23 #include <glib/gmain.h>
  24 #include <sys/socket.h>
  25 #include <netinet/in.h>
  26 #include <glib/glist.h>
  27 #include <stdio.h>
  28 #include <stdlib.h>
  29 #include <sys/types.h>
  30 #include <signal.h>
  31 #include <errno.h>
  32 #include <glib/giochannel.h>
  33 #include <sys/ioctl.h>
  34 #include <string.h>
  35 #include <glib/galloca.h>
  36 #include <glib/gprintf.h>
  37 #include <glib/grand.h>
  38
  39 #include "network.h"
  40 #include "packet.h"
  41 #include "main.h"       /* for optarg_verbose */
  42
  43
  44 /* Config: */
  45 #define NETWORK_PATHNAME_PID "/var/run/udpgate.pid"
  46 #define SOCK_SOURCE_CHECK_EVENTS (G_IO_IN)      /* |G_IO_PRI */
  47 #define SOCK_SOURCE_CHECK_REVENTS (SOCK_SOURCE_CHECK_EVENTS)    /* |G_IO_ERR|G_IO_HUP|G_IO_NVAL */
  48 #define SERVER_INADDR 0x7F000001
  49 #undef  SERVER_INADDR
  50 #define SERVER_INADDR 0x511F02EA        /* paulina.vellum.cz = 81.31.2.234; host order */
  51 #define SERVER_PORT   9201      /* host order */
  52 #define PROBE_INADDR  SERVER_INADDR     /* host order */
  53 #define PROBE_PORT    8201      /* host order */
  54 #define CLIENT_TIMEOUT_SEC (5*60)
  55 #define PROBE_TIMEOUT_SEC (5)
  56
  57
  58 void (*network_notify_hostip)(guint32 hostip_guint32);
  59
  60
  61 struct client {
  62         GPollFD gpollfd;
  63         struct sockaddr_in sockaddr_in_from;
  64         guint timeout_id;
  65         };
  66
  67 static GSource *sock_gsource;
  68
  69 static GList *sock_client_list; /* of 'struct client *', incl. 'master' and 'probe' */
  70 static struct client *master;   /* no 'timeout' permitted */
  71 static struct client *probe;    /* 'timeout' permitted */
  72 static guint32 probe_unique;
  73
  74 static gboolean write_daemon_running(pid_t pid);
  75
  76 pid_t is_daemon_running(void)
  77 {
  78 FILE *f;
  79 char buf[LINE_MAX],*got;
  80 int pid_int;
  81
  82         if (sock_gsource)
  83                 return getpid();
  84
  85         if (!(f=fopen(NETWORK_PATHNAME_PID,"r")))
  86                 goto err;
  87         got=fgets(buf,sizeof(buf),f);
  88         fclose(f);      /* FIXME: error ignored */
  89         if (got!=buf) {
  90 err_unlink:
  91                 write_daemon_running((pid_t)-1);        /* unlink */
  92 err:
  93                 return (pid_t)-1;
  94                 }
  95         pid_int=atoi(buf);
  96         if (pid_int<=1)
  97                 goto err_unlink;
  98         if (kill((pid_t)pid_int,0)) {
  99                 if (errno==ESRCH)
 100                         goto err_unlink;
 101                 goto err;
 102                 }
 103         return (pid_t)pid_int;
 104 }
 105
 106 static gboolean write_daemon_running(pid_t pid)
 107 {
 108 FILE *f;
 109
 110         if (pid==(pid_t)-1) {
 111                 if (unlink(NETWORK_PATHNAME_PID)) {
 112                         if (errno!=ENOENT)
 113                                 g_warning(_("Error removing PID file \"%s\": %m"),NETWORK_PATHNAME_PID);
 114                         return FALSE;
 115                         }
 116                 return TRUE;
 117                 }
 118         if (!(f=fopen(NETWORK_PATHNAME_PID,"w"))) {
 119                 g_warning(_("Error writing PID %d to \"%s\": %m"),(int)pid,NETWORK_PATHNAME_PID);
 120                 return FALSE;
 121                 }
 122         fprintf(f,"%d\n",(int)pid);     /* errors ignored */
 123         fclose(f);      /* FIXME: error ignored */
 124         return TRUE;
 125 }
 126
 127 static void client_timeout_remove(struct client *client)
 128 {
 129         g_return_if_fail(client!=NULL);
 130         g_return_if_fail(client!=master);
 131
 132         if (client->timeout_id) {
 133 gboolean errgboolean;
 134
 135                 if (optarg_verbose)
 136                         g_message(_("Client fd %d removed timeout id %d"),client->gpollfd.fd,client->timeout_id);
 137                 errgboolean=g_source_remove(client->timeout_id);
 138                 g_assert(errgboolean==TRUE);
 139                 client->timeout_id=0;
 140                 }
 141 }
 142
 143 static gboolean client_touch_timeout(struct client *client);
 144
 145 static void client_touch(struct client *client)
 146 {
 147         g_return_if_fail(client!=NULL);
 148         g_return_if_fail(client!=master);
 149
 150         client_timeout_remove(client);
 151         client->timeout_id=g_timeout_add(
 152                         (client==probe ? PROBE_TIMEOUT_SEC*1000 : CLIENT_TIMEOUT_SEC*1000),     /* interval; msec */
 153                         (GSourceFunc)client_touch_timeout,      /* function */
 154                         client);        /* data */
 155         if (optarg_verbose)
 156                 g_message(_("Client fd %d new timeout id %d"),client->gpollfd.fd,client->timeout_id);
 157         g_assert(client->timeout_id!=0);
 158 }
 159
 160 static void client_destroy(struct client *client);
 161
 162 static gboolean client_touch_timeout(struct client *client)
 163 {
 164         g_return_val_if_fail(client!=NULL,FALSE);       /* FALSE=>should be removed */
 165         g_return_val_if_fail(client!=master,FALSE);     /* FALSE=>should be removed */
 166
 167         if (optarg_verbose)
 168                 g_message(_("Client fd %d timeout id %d occured/entered"),client->gpollfd.fd,client->timeout_id);
 169
 170         /* Do not destroy the timeout in client_destroy().
 171          * It would crash GLib - we remove it be returning FALSE from here.
 172          */
 173         g_assert(client->timeout_id!=0);
 174         client->timeout_id=0;
 175
 176         if (client==probe) {
 177                 network_stop();
 178                 /* Never destroy 'client' now - it has been destroyed by network_stop()! */
 179                 if (network_notify_hostip)
 180                         (*network_notify_hostip)(0);
 181                 }
 182         else {
 183                 client_destroy(client);
 184                 }
 185
 186         if (optarg_verbose)
 187                 g_message(_("Client timeout occurance finish"));
 188
 189         return FALSE;   /* GSource should be removed */
 190 }
 191
 192 static void handle_master_probe(const void *packet,size_t gotlen,const struct sockaddr_in *sockaddr_in_from)
 193 {
 194 GHashTable *got_hash;
 195 gpointer got_unique_gpointer;
 196 gpointer hostip_gpointer;
 197 guint32 hostip_guint32;
 198
 199         g_return_if_fail(packet!=NULL);
 200         g_return_if_fail(sockaddr_in_from!=NULL);
 201
 202         if (!probe)
 203                 return;
 204
 205         if (!(got_hash=packet_disassembly(packet,gotlen)))
 206                 return;
 207         if (!(g_hash_table_lookup_extended(
 208                         got_hash,       /* hash_table */
 209                         GUINT_TO_POINTER(PACKET_ELEM_TYPE_DATA_GUINT32),        /* lookup_key */
 210                         NULL,   /* orig_key */
 211                         &got_unique_gpointer))) {
 212 err_packet_disassembly_destroy_got_hash:
 213                 packet_disassembly_destroy(got_hash);
 214                 return;
 215                 }
 216         if (GPOINTER_TO_UINT(got_unique_gpointer)!=probe_unique)
 217                 goto err_packet_disassembly_destroy_got_hash;
 218         if (!(g_hash_table_lookup_extended(
 219                         got_hash,       /* hash_table */
 220                         GUINT_TO_POINTER(PACKET_ELEM_TYPE_CLIENT_INADDR),       /* lookup_key */
 221                         NULL,   /* orig_key */
 222                         &hostip_gpointer)))
 223                 goto err_packet_disassembly_destroy_got_hash;
 224         hostip_guint32=GPOINTER_TO_UINT(hostip_gpointer);
 225         packet_disassembly_destroy(got_hash);
 226
 227         client_destroy(probe);
 228         if (network_notify_hostip)
 229                 (*network_notify_hostip)(hostip_guint32);
 230 }
 231
 232 static struct client *client_new(void);
 233
 234 static void handle_master(struct client *master)
 235 {
 236 ssize_t gotlen;
 237 struct sockaddr_in sockaddr_in_from;
 238 char packet[0x10000];
 239 struct client *client;
 240 struct sockaddr_in sockaddr_in_server;
 241 socklen_t sockaddr_in_from_length;
 242
 243         g_return_if_fail(master!=NULL);
 244
 245         sockaddr_in_from_length=sizeof(sockaddr_in_from);
 246         while (-1!=(gotlen=recvfrom(
 247                         master->gpollfd.fd,     /* s */
 248                         packet, /* buf */
 249                         sizeof(packet), /* len */
 250                         0,      /* flags */
 251                         (struct sockaddr *)&sockaddr_in_from,   /* from */
 252                         &sockaddr_in_from_length))) {   /* fromlen */
 253 GList *clientl;
 254
 255                 if (sockaddr_in_from_length!=sizeof(sockaddr_in_from))  /* FIXME: errors reporting */
 256                         continue;
 257
 258                 if (packet_recognized(packet,gotlen)) {
 259                         handle_master_probe(packet,gotlen,&sockaddr_in_from);
 260                         continue;
 261                         }
 262
 263                 /* FIXME: Performance: Ugly search... */
 264                 for (clientl=sock_client_list;clientl;clientl=clientl->next) {
 265                         client=clientl->data;
 266                         if (client==master)
 267                                 continue;
 268                         if (1
 269                                         && client->sockaddr_in_from.sin_family     ==sockaddr_in_from.sin_family
 270                                         && client->sockaddr_in_from.sin_port       ==sockaddr_in_from.sin_port
 271                                         && client->sockaddr_in_from.sin_addr.s_addr==sockaddr_in_from.sin_addr.s_addr)
 272                                 break;
 273                         }
 274                 if (!clientl) {
 275                         client=client_new();
 276                         client->sockaddr_in_from=sockaddr_in_from;
 277                         }
 278                 client_touch(client);
 279                 UDPGATE_MEMZERO(&sockaddr_in_server);
 280                 sockaddr_in_server.sin_family=AF_INET;
 281                 sockaddr_in_server.sin_port=htons(SERVER_PORT);
 282                 sockaddr_in_server.sin_addr.s_addr=htonl(SERVER_INADDR);
 283                 /* FIXME: errors checking */
 284                 sendto(
 285                                 client->gpollfd.fd,     /* s */
 286                                 packet, /* msg */
 287                                 gotlen, /* len */
 288                                 0,      /* flags */
 289                                 (struct sockaddr *)&sockaddr_in_server, /* to */
 290                                 sizeof(sockaddr_in_server));    /* tolen */
 291                 }
 292 }
 293
 294 static void handle_probe(struct client *probe)
 295 {
 296 ssize_t gotlen;
 297 struct sockaddr_in sockaddr_in_from;
 298 char packet[0x10000];
 299 socklen_t sockaddr_in_from_length;
 300
 301         g_return_if_fail(probe!=NULL);
 302
 303         sockaddr_in_from_length=sizeof(sockaddr_in_from);
 304         while (-1!=(gotlen=recvfrom(
 305                         master->gpollfd.fd,     /* s */
 306                         packet, /* buf */
 307                         sizeof(packet), /* len */
 308                         0,      /* flags */
 309                         (struct sockaddr *)&sockaddr_in_from,   /* from */
 310                         &sockaddr_in_from_length))) {   /* fromlen */
 311                 if (sockaddr_in_from_length!=sizeof(sockaddr_in_from))  /* FIXME: errors reporting */
 312                         continue;
 313
 314                 /* Probe socket should have no response; maybe some ICMP errors - ignored. */
 315                 }
 316 }
 317
 318 static void handle_client(struct client *client)
 319 {
 320 ssize_t gotlen;
 321 struct sockaddr_in sockaddr_in_from;
 322 char packet [0x10000];
 323 socklen_t sockaddr_in_from_length;
 324
 325         g_return_if_fail(client!=NULL);
 326         g_return_if_fail(master!=NULL);
 327
 328         while (-1!=(gotlen=recvfrom(
 329                         client->gpollfd.fd,     /* s */
 330                         packet, /* buf */
 331                         sizeof(packet), /* len */
 332                         0,      /* flags */
 333                         (struct sockaddr *)&sockaddr_in_from,   /* from */
 334                         &sockaddr_in_from_length))) {   /* fromlen */
 335                 if (sockaddr_in_from_length!=sizeof(sockaddr_in_from))  /* FIXME: errors reporting */
 336                         continue;
 337                 client_touch(client);
 338                 /* FIXME: errors checking */
 339                 sendto(
 340                                 master->gpollfd.fd,     /* s */
 341                                 packet, /* msg */
 342                                 gotlen, /* len */
 343                                 0,      /* flags */
 344                                 (struct sockaddr *)&client->sockaddr_in_from,   /* to */
 345                                 sizeof(client->sockaddr_in_from));      /* tolen */
 346                 }
 347 }
 348
 349 static gboolean sock_source_callback(gpointer data /* unused */)
 350 {
 351 GList *clientl;
 352
 353         for (clientl=sock_client_list;clientl;clientl=clientl->next) {
 354 struct client *client=clientl->data;
 355
 356                 if (client->gpollfd.revents&SOCK_SOURCE_CHECK_REVENTS) {
 357                         /**/ if (client==master)
 358                                 handle_master(client);
 359                         else if (client==probe)
 360                                 handle_probe(client);
 361                         else
 362                                 handle_client(client);
 363                         }
 364                 }
 365
 366         return TRUE; /* the source should be kept active */
 367 }
 368
 369 static gboolean sock_source_prepare(GSource *source,gint *timeout)
 370 {
 371         *timeout=-1;
 372
 373         return FALSE;
 374 }
 375
 376 static gboolean sock_source_check(GSource *source)
 377 {
 378 GList *clientl;
 379
 380         for (clientl=sock_client_list;clientl;clientl=clientl->next) {
 381 struct client *client=clientl->data;
 382
 383                 if (client->gpollfd.revents&SOCK_SOURCE_CHECK_REVENTS)
 384                         return TRUE;
 385                 }
 386         return FALSE;
 387 }
 388
 389 static gboolean sock_source_dispatch(GSource *source,GSourceFunc callback,gpointer user_data)
 390 {
 391         g_assert(callback!=NULL);
 392         return (*callback)(user_data);
 393 }
 394
 395 static GSourceFuncs sock_source_watch_funcs={
 396                 sock_source_prepare,
 397                 sock_source_check,
 398                 sock_source_dispatch,
 399                 NULL, /* finalize */
 400                 };
 401
 402 static void sock_gsource_destroy(void)
 403 {
 404         while (sock_client_list)
 405                 client_destroy(sock_client_list->data);
 406
 407         g_assert(master==NULL);
 408
 409         if (sock_gsource) {
 410                 g_source_destroy(sock_gsource);
 411                 sock_gsource=NULL;
 412                 }
 413
 414         write_daemon_running((pid_t)-1);        /* unlink */
 415 }
 416
 417 static gboolean sock_gsource_new(void)
 418 {
 419         if (sock_gsource)
 420                 return TRUE;
 421
 422         g_assert(sock_client_list==NULL);
 423
 424         /* attach sock_source_callback() to watch for any abnormalities
 425          * on our open pipe 'parentheart_fds' and terminate the child if parent dies.
 426          */
 427         if (!(sock_gsource=g_source_new(&sock_source_watch_funcs,sizeof(GSource)))) {
 428                 g_warning("g_source_new(): %m");
 429                 return FALSE;
 430                 }
 431         g_source_set_callback(
 432                         sock_gsource,  /* source */
 433                         sock_source_callback,  /* func */
 434                         NULL, /* data */
 435                         NULL);  /* notify */
 436         if (!g_source_attach(   /* returns 'guint' id */
 437                         sock_gsource,  /* source */
 438                         NULL)) {        /* context; NULL means 'default context' */
 439                 g_warning("g_source_attach(gsource,NULL): %m");
 440                 sock_gsource_destroy();
 441                 return FALSE;
 442                 }
 443         return TRUE;
 444 }
 445
 446 static struct client *client_new(void)
 447 {
 448 struct client *client;
 449 static unsigned long oneul=1;
 450 int sock;
 451
 452         if (!sock_gsource_new())
 453                 return FALSE;
 454
 455         if (-1==(sock=socket(AF_INET,SOCK_DGRAM,0))) {
 456                 g_warning("socket(AF_INET,SOCK_DGRAM): %m");
 457                 return NULL;
 458                 }
 459         if (ioctl(sock,FIONBIO,&oneul)) {       /* non-blocking mode */
 460                 g_warning("ioctl(sock,FIONBIO,&1): %m");
 461                 close(sock);    /* errors ignored */
 462                 return NULL;
 463                 }
 464
 465         udpgate_new(client);
 466         client->gpollfd.fd=sock;
 467         client->gpollfd.events=SOCK_SOURCE_CHECK_EVENTS;
 468         client->gpollfd.revents=0;
 469         client->timeout_id=0;
 470         sock_client_list=g_list_prepend(sock_client_list,client);
 471         g_source_add_poll(sock_gsource,&client->gpollfd);
 472
 473         if (optarg_verbose)
 474                 g_message(_("Client fd %d created"),client->gpollfd.fd);
 475
 476         return client;
 477 }
 478
 479 static void client_destroy(struct client *client)
 480 {
 481         g_return_if_fail(client!=NULL);
 482
 483         if (!sock_gsource_new())
 484                 return;
 485
 486         if (optarg_verbose)
 487                 g_message(_("Client fd %d timeout id %d destroy enter"),client->gpollfd.fd,client->timeout_id);
 488
 489         if (client==master) {
 490                 master=NULL;
 491                 g_assert(client->timeout_id==0);
 492                 }
 493         else {
 494                 if (client==probe)
 495                         probe=NULL;
 496                 client_timeout_remove(client);
 497                 }
 498
 499         g_source_remove_poll(sock_gsource,&client->gpollfd);
 500         sock_client_list=g_list_remove(sock_client_list,client);
 501         close(client->gpollfd.fd);      /* errors ignored */
 502
 503         if (optarg_verbose)
 504                 g_message(_("Client fd %d timeout id %d destroy finish"),client->gpollfd.fd,client->timeout_id);
 505
 506         g_free(client);
 507 }
 508
 509 static gboolean probe_send(struct client *probe,gint port_local)
 510 {
 511 struct sockaddr_in sockaddr_in_server;
 512 GHashTable *probe_hash;
 513 gpointer packet;
 514 size_t packet_length;
 515
 516         g_return_val_if_fail(probe!=NULL,FALSE);
 517
 518         probe_unique=g_random_int();
 519
 520         probe_hash=g_hash_table_new(
 521                         g_direct_hash,  /* hash_func */
 522                         g_direct_equal);        /* key_equal_func */
 523         g_hash_table_insert(probe_hash,GUINT_TO_POINTER(PACKET_ELEM_TYPE_CLIENT_PORT) ,GUINT_TO_POINTER(port_local));
 524         g_hash_table_insert(probe_hash,GUINT_TO_POINTER(PACKET_ELEM_TYPE_DATA_GUINT32),GUINT_TO_POINTER(probe_unique));
 525         packet=packet_assembly(&packet_length,probe_hash);
 526         g_hash_table_destroy(probe_hash);
 527         if (!packet)
 528                 return FALSE;
 529
 530         UDPGATE_MEMZERO(&sockaddr_in_server);
 531         sockaddr_in_server.sin_family=AF_INET;
 532         sockaddr_in_server.sin_port=htons(PROBE_PORT);
 533         sockaddr_in_server.sin_addr.s_addr=htonl(PROBE_INADDR);
 534         /* FIXME: errors checking */
 535         sendto(
 536                         probe->gpollfd.fd,      /* s */
 537                         packet, /* msg */
 538                         packet_length,  /* len */
 539                         0,      /* flags */
 540                         (struct sockaddr *)&sockaddr_in_server, /* to */
 541                         sizeof(sockaddr_in_server));    /* tolen */
 542
 543         return TRUE;
 544 }
 545
 546 gboolean network_start(gint port)
 547 {
 548 pid_t daemon_pid;
 549 struct sockaddr_in sockaddr_in;
 550
 551         g_return_val_if_fail(port>=0,FALSE);
 552
 553         if ((pid_t)-1!=(daemon_pid=is_daemon_running())) {
 554                 g_warning(_("Cannot start network daemon: Daemon is already running on PID %d"),(int)daemon_pid);
 555                 return FALSE;
 556                 }
 557
 558         /* Setup 'master': */
 559         g_assert(master==NULL);
 560         if (!(master=client_new()))
 561                 return FALSE;
 562         UDPGATE_MEMZERO(&sockaddr_in);
 563         sockaddr_in.sin_family=AF_INET;
 564         sockaddr_in.sin_port=htons(port);
 565         sockaddr_in.sin_addr.s_addr=htonl(INADDR_ANY);
 566         if (bind(master->gpollfd.fd,(struct sockaddr *)&sockaddr_in,sizeof(sockaddr_in))) {
 567                 g_warning("bind(sock,{AF_INET,INADDR_ANY:%d}): %m",(int)port);
 568 err_sock_gsource_destroy:
 569                 sock_gsource_destroy();
 570                 return FALSE;
 571                 }
 572
 573         /* Setup 'probe': */
 574         if (!(probe=client_new()))
 575                 goto err_sock_gsource_destroy;
 576         probe_send(probe,port);
 577         client_touch(probe);    /* timeout */
 578
 579         write_daemon_running(getpid());
 580         return TRUE;
 581 }
 582
 583 gboolean network_stop(void)
 584 {
 585 pid_t daemon_pid;
 586 int errno_save;
 587
 588         if ((pid_t)-1==(daemon_pid=is_daemon_running())) {
 589                 g_warning(_("Cannot stop network daemon: Daemon is not running"));
 590                 return FALSE;
 591                 }
 592         if (daemon_pid==getpid()) {
 593                 sock_gsource_destroy();
 594                 return TRUE;
 595                 }
 596         errno=0;
 597         kill(daemon_pid,SIGKILL);
 598         errno_save=errno;
 599         if (errno_save)  {
 600                 g_warning(udpgate_printf_alloca(_("Unable to stop the daemon at PID %d: %s"),
 601                                 (int)daemon_pid,strerror(errno_save)));
 602                 return FALSE;
 603                 }
 604         return TRUE;
 605 }