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