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,const gchar *hostip_string);
  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,NULL);
 166                 }
 167
 168         client_destroy(client);
 169
 170         return FALSE;   /* GSource should be removed */
 171 }
 172
 173 static struct client *client_new(void);
 174
 175 static void handle_master(struct client *master)
 176 {
 177 ssize_t gotlen;
 178 struct sockaddr_in sockaddr_in_from;
 179 char packet[0x10000];
 180 struct client *client;
 181 struct sockaddr_in sockaddr_in_server;
 182 socklen_t sockaddr_in_from_length;
 183
 184         g_return_if_fail(master!=NULL);
 185
 186         sockaddr_in_from_length=sizeof(sockaddr_in_from);
 187         while (-1!=(gotlen=recvfrom(
 188                         master->gpollfd.fd,     /* s */
 189                         packet, /* buf */
 190                         sizeof(packet), /* len */
 191                         0,      /* flags */
 192                         (struct sockaddr *)&sockaddr_in_from,   /* from */
 193                         &sockaddr_in_from_length))) {   /* fromlen */
 194 GList *clientl;
 195
 196                 if (sockaddr_in_from_length!=sizeof(sockaddr_in_from))  /* FIXME: errors reporting */
 197                         continue;
 198                 /* FIXME: Performance: Ugly search... */
 199                 for (clientl=sock_client_list;clientl;clientl=clientl->next) {
 200                         client=clientl->data;
 201                         if (client==master)
 202                                 continue;
 203                         if (1
 204                                         && client->sockaddr_in_from.sin_family     ==sockaddr_in_from.sin_family
 205                                         && client->sockaddr_in_from.sin_port       ==sockaddr_in_from.sin_port
 206                                         && client->sockaddr_in_from.sin_addr.s_addr==sockaddr_in_from.sin_addr.s_addr)
 207                                 break;
 208                         }
 209                 if (!clientl) {
 210                         client=client_new();
 211                         client->sockaddr_in_from=sockaddr_in_from;
 212                         }
 213                 client_touch(client);
 214                 UDPGATE_MEMZERO(&sockaddr_in_server);
 215                 sockaddr_in_server.sin_family=AF_INET;
 216                 sockaddr_in_server.sin_port=htons(SERVER_PORT);
 217                 sockaddr_in_server.sin_addr.s_addr=htonl(SERVER_INADDR);
 218                 /* FIXME: errors checking */
 219                 sendto(
 220                                 client->gpollfd.fd,     /* s */
 221                                 packet, /* msg */
 222                                 gotlen, /* len */
 223                                 0,      /* flags */
 224                                 (struct sockaddr *)&sockaddr_in_server, /* to */
 225                                 sizeof(sockaddr_in_server));    /* tolen */
 226                 }
 227 }
 228
 229 static void handle_probe(struct client *probe)
 230 {
 231 ssize_t gotlen;
 232 struct sockaddr_in sockaddr_in_from;
 233 char packet[0x10000];
 234 socklen_t sockaddr_in_from_length;
 235
 236         g_return_if_fail(probe!=NULL);
 237
 238         sockaddr_in_from_length=sizeof(sockaddr_in_from);
 239         while (-1!=(gotlen=recvfrom(
 240                         master->gpollfd.fd,     /* s */
 241                         packet, /* buf */
 242                         sizeof(packet), /* len */
 243                         0,      /* flags */
 244                         (struct sockaddr *)&sockaddr_in_from,   /* from */
 245                         &sockaddr_in_from_length))) {   /* fromlen */
 246 static GHashTable *got_hash;
 247 static gpointer got_unique_gpointer;
 248 static gpointer hostip_gpointer;
 249 static guint32 hostip_guint32;
 250
 251                 if (sockaddr_in_from_length!=sizeof(sockaddr_in_from))  /* FIXME: errors reporting */
 252                         continue;
 253                 if (!(got_hash=packet_disassembly(packet,gotlen)))
 254                         continue;
 255                 if (!(g_hash_table_lookup_extended(
 256                                 got_hash,       /* hash_table */
 257                                 GUINT_TO_POINTER(PACKET_ELEM_TYPE_DATA_GUINT32),        /* lookup_key */
 258                                 NULL,   /* orig_key */
 259                                 &got_unique_gpointer))) {
 260 err_packet_disassembly_destroy_got_hash:
 261                         packet_disassembly_destroy(got_hash);
 262                         continue;
 263                         }
 264                 if (GPOINTER_TO_UINT(got_unique_gpointer)!=probe_unique)
 265                         goto err_packet_disassembly_destroy_got_hash;
 266                 if (!(g_hash_table_lookup_extended(
 267                                 got_hash,       /* hash_table */
 268                                 GUINT_TO_POINTER(PACKET_ELEM_TYPE_CLIENT_INADDR),       /* lookup_key */
 269                                 NULL,   /* orig_key */
 270                                 &hostip_gpointer)))
 271                         goto err_packet_disassembly_destroy_got_hash;
 272                 hostip_guint32=GPOINTER_TO_UINT(hostip_gpointer);
 273                 packet_disassembly_destroy(got_hash);
 274
 275                 client_destroy(probe);
 276                 if (network_notify_hostip)
 277                         (*network_notify_hostip)(hostip_guint32,HOSTIP_GUINT32_TO_STRING(hostip_guint32));
 278                 }
 279 }
 280
 281 static void handle_client(struct client *client)
 282 {
 283 ssize_t gotlen;
 284 struct sockaddr_in sockaddr_in_from;
 285 char packet [0x10000];
 286 socklen_t sockaddr_in_from_length;
 287
 288         g_return_if_fail(client!=NULL);
 289         g_return_if_fail(master!=NULL);
 290
 291         while (-1!=(gotlen=recvfrom(
 292                         client->gpollfd.fd,     /* s */
 293                         packet, /* buf */
 294                         sizeof(packet), /* len */
 295                         0,      /* flags */
 296                         (struct sockaddr *)&sockaddr_in_from,   /* from */
 297                         &sockaddr_in_from_length))) {   /* fromlen */
 298                 if (sockaddr_in_from_length!=sizeof(sockaddr_in_from))  /* FIXME: errors reporting */
 299                         continue;
 300                 client_touch(client);
 301                 /* FIXME: errors checking */
 302                 sendto(
 303                                 master->gpollfd.fd,     /* s */
 304                                 packet, /* msg */
 305                                 gotlen, /* len */
 306                                 0,      /* flags */
 307                                 (struct sockaddr *)&client->sockaddr_in_from,   /* to */
 308                                 sizeof(client->sockaddr_in_from));      /* tolen */
 309                 }
 310 }
 311
 312 static gboolean sock_source_callback(gpointer data /* unused */)
 313 {
 314 GList *clientl;
 315
 316         for (clientl=sock_client_list;clientl;clientl=clientl->next) {
 317 struct client *client=clientl->data;
 318
 319                 if (client->gpollfd.revents&SOCK_SOURCE_CHECK_REVENTS) {
 320                         /**/ if (client==master)
 321                                 handle_master(client);
 322                         else if (client==probe)
 323                                 handle_probe(client);
 324                         else
 325                                 handle_client(client);
 326                         }
 327                 }
 328
 329         return TRUE; /* the source should be kept active */
 330 }
 331
 332 static gboolean sock_source_prepare(GSource *source,gint *timeout)
 333 {
 334         *timeout=-1;
 335
 336         return FALSE;
 337 }
 338
 339 static gboolean sock_source_check(GSource *source)
 340 {
 341 GList *clientl;
 342
 343         for (clientl=sock_client_list;clientl;clientl=clientl->next) {
 344 struct client *client=clientl->data;
 345
 346                 if (client->gpollfd.revents&SOCK_SOURCE_CHECK_REVENTS)
 347                         return TRUE;
 348                 }
 349         return FALSE;
 350 }
 351
 352 static gboolean sock_source_dispatch(GSource *source,GSourceFunc callback,gpointer user_data)
 353 {
 354         g_assert(callback!=NULL);
 355         return (*callback)(user_data);
 356 }
 357
 358 static GSourceFuncs sock_source_watch_funcs={
 359                 sock_source_prepare,
 360                 sock_source_check,
 361                 sock_source_dispatch,
 362                 NULL, /* finalize */
 363                 };
 364
 365 static void sock_gsource_destroy(void)
 366 {
 367         while (sock_client_list)
 368                 client_destroy(sock_client_list->data);
 369
 370         g_assert(master==NULL);
 371
 372         if (sock_gsource) {
 373                 g_source_destroy(sock_gsource);
 374                 sock_gsource=NULL;
 375                 }
 376
 377         write_daemon_running((pid_t)-1);        /* unlink */
 378 }
 379
 380 static gboolean sock_gsource_new(void)
 381 {
 382         if (sock_gsource)
 383                 return TRUE;
 384
 385         g_assert(sock_client_list==NULL);
 386
 387         /* attach sock_source_callback() to watch for any abnormalities
 388          * on our open pipe 'parentheart_fds' and terminate the child if parent dies.
 389          */
 390         if (!(sock_gsource=g_source_new(&sock_source_watch_funcs,sizeof(GSource)))) {
 391                 g_warning("g_source_new(): %m");
 392                 return FALSE;
 393                 }
 394         g_source_set_callback(
 395                         sock_gsource,  /* source */
 396                         sock_source_callback,  /* func */
 397                         NULL, /* data */
 398                         NULL);  /* notify */
 399         if (!g_source_attach(   /* returns 'guint' id */
 400                         sock_gsource,  /* source */
 401                         NULL)) {        /* context; NULL means 'default context' */
 402                 g_warning("g_source_attach(gsource,NULL): %m");
 403                 sock_gsource_destroy();
 404                 return FALSE;
 405                 }
 406         return TRUE;
 407 }
 408
 409 static struct client *client_new(void)
 410 {
 411 struct client *client;
 412 static unsigned long oneul=1;
 413 int sock;
 414
 415         if (!sock_gsource_new())
 416                 return FALSE;
 417
 418         if (-1==(sock=socket(AF_INET,SOCK_DGRAM,0))) {
 419                 g_warning("socket(AF_INET,SOCK_DGRAM): %m");
 420                 return NULL;
 421                 }
 422         if (ioctl(sock,FIONBIO,&oneul)) {       /* non-blocking mode */
 423                 g_warning("ioctl(sock,FIONBIO,&1): %m");
 424                 close(sock);    /* errors ignored */
 425                 return NULL;
 426                 }
 427
 428         udpgate_new(client);
 429         client->gpollfd.fd=sock;
 430         client->gpollfd.events=SOCK_SOURCE_CHECK_EVENTS;
 431         client->gpollfd.revents=0;
 432         client->timeout_id=0;
 433         sock_client_list=g_list_prepend(sock_client_list,client);
 434         g_source_add_poll(sock_gsource,&client->gpollfd);
 435
 436         return client;
 437 }
 438
 439 static void client_destroy(struct client *client)
 440 {
 441         g_return_if_fail(client!=NULL);
 442
 443         if (!sock_gsource_new())
 444                 return;
 445
 446         if (client==master) {
 447                 master=NULL;
 448                 g_assert(client->timeout_id==0);
 449                 }
 450         else {
 451                 if (client==probe)
 452                         probe=NULL;
 453                 client_timeout_remove(client);
 454                 }
 455
 456         g_source_remove_poll(sock_gsource,&client->gpollfd);
 457         sock_client_list=g_list_remove(sock_client_list,client);
 458         close(client->gpollfd.fd);      /* errors ignored */
 459         g_free(client);
 460 }
 461
 462 static gboolean probe_send(struct client *probe,gint port_local)
 463 {
 464 struct sockaddr_in sockaddr_in_server;
 465 GHashTable *probe_hash;
 466 gpointer packet;
 467 size_t packet_length;
 468
 469         g_return_val_if_fail(probe!=NULL,FALSE);
 470
 471         probe_unique=g_random_int();
 472
 473         probe_hash=g_hash_table_new(
 474                         g_direct_hash,  /* hash_func */
 475                         g_direct_equal);        /* key_equal_func */
 476         g_hash_table_insert(probe_hash,GUINT_TO_POINTER(PACKET_ELEM_TYPE_CLIENT_PORT) ,GUINT_TO_POINTER(port_local));
 477         g_hash_table_insert(probe_hash,GUINT_TO_POINTER(PACKET_ELEM_TYPE_DATA_GUINT32),GUINT_TO_POINTER(probe_unique));
 478         packet=packet_assembly(&packet_length,probe_hash);
 479         g_hash_table_destroy(probe_hash);
 480         if (!packet)
 481                 return FALSE;
 482
 483         UDPGATE_MEMZERO(&sockaddr_in_server);
 484         sockaddr_in_server.sin_family=AF_INET;
 485         sockaddr_in_server.sin_port=htons(PROBE_PORT);
 486         sockaddr_in_server.sin_addr.s_addr=htonl(PROBE_INADDR);
 487         /* FIXME: errors checking */
 488         sendto(
 489                         probe->gpollfd.fd,      /* s */
 490                         packet, /* msg */
 491                         packet_length,  /* len */
 492                         0,      /* flags */
 493                         (struct sockaddr *)&sockaddr_in_server, /* to */
 494                         sizeof(sockaddr_in_server));    /* tolen */
 495
 496         return TRUE;
 497 }
 498
 499 gboolean network_start(gint port)
 500 {
 501 pid_t daemon_pid;
 502 struct sockaddr_in sockaddr_in;
 503
 504         g_return_val_if_fail(port>=0,FALSE);
 505
 506         if ((pid_t)-1!=(daemon_pid=is_daemon_running())) {
 507                 g_warning(_("Cannot start network daemon: Daemon is already running on PID %d"),(int)daemon_pid);
 508                 return FALSE;
 509                 }
 510
 511         /* Setup 'master': */
 512         g_assert(master==NULL);
 513         if (!(master=client_new()))
 514                 return FALSE;
 515         UDPGATE_MEMZERO(&sockaddr_in);
 516         sockaddr_in.sin_family=AF_INET;
 517         sockaddr_in.sin_port=htons(port);
 518         sockaddr_in.sin_addr.s_addr=INADDR_ANY;
 519         if (bind(master->gpollfd.fd,(struct sockaddr *)&sockaddr_in,sizeof(sockaddr_in))) {
 520                 g_warning("bind(sock,{AF_INET,INADDR_ANY:%d}): %m",(int)port);
 521 err_sock_gsource_destroy:
 522                 sock_gsource_destroy();
 523                 return FALSE;
 524                 }
 525
 526         /* Setup 'probe': */
 527         if (!(probe=client_new()))
 528                 goto err_sock_gsource_destroy;
 529         probe_send(probe,port);
 530         client_touch(probe);    /* timeout */
 531
 532         write_daemon_running(getpid());
 533         return TRUE;
 534 }
 535
 536 gboolean network_stop(void)
 537 {
 538 pid_t daemon_pid;
 539 int errno_save;
 540
 541         if ((pid_t)-1==(daemon_pid=is_daemon_running())) {
 542                 g_warning(_("Cannot stop network daemon: Daemon is not running"));
 543                 return FALSE;
 544                 }
 545         if (daemon_pid==getpid()) {
 546                 sock_gsource_destroy();
 547                 return TRUE;
 548                 }
 549         errno=0;
 550         kill(daemon_pid,SIGKILL);
 551         errno_save=errno;
 552         if (errno_save)  {
 553                 g_warning(udpgate_printf_alloca(_("Unable to stop the daemon at PID %d: %s"),
 554                                 (int)daemon_pid,strerror(errno_save)));
 555                 return FALSE;
 556                 }
 557         return TRUE;
 558 }