citadel/modules/network/serv_netconfig.c

   1 /*
   2  * This module handles shared rooms, inter-Citadel mail, and outbound
   3  * mailing list processing.
   4  *
   5  * Copyright (c) 2000-2012 by the citadel.org team
   6  *
   7  *  This program is open source software; you can redistribute it and/or modify
   8  *  it under the terms of the GNU General Public License, version 3.
   9  *
  10  *  This program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU General Public License for more details.
  14  *
  15  * ** NOTE **   A word on the S_NETCONFIGS semaphore:
  16  * This is a fairly high-level type of critical section.  It ensures that no
  17  * two threads work on the netconfigs files at the same time.  Since we do
  18  * so many things inside these, here are the rules:
  19  *  1. begin_critical_section(S_NETCONFIGS) *before* begin_ any others.
  20  *  2. Do *not* perform any I/O with the client during these sections.
  21  *
  22  */
  23
  24 /*
  25  * Duration of time (in seconds) after which pending list subscribe/unsubscribe
  26  * requests that have not been confirmed will be deleted.
  27  */
  28 #define EXP     259200  /* three days */
  29
  30 #include "sysdep.h"
  31 #include <stdlib.h>
  32 #include <unistd.h>
  33 #include <stdio.h>
  34 #include <fcntl.h>
  35 #include <ctype.h>
  36 #include <signal.h>
  37 #include <pwd.h>
  38 #include <errno.h>
  39 #include <sys/stat.h>
  40 #include <sys/types.h>
  41 #include <dirent.h>
  42 #if TIME_WITH_SYS_TIME
  43 # include <sys/time.h>
  44 # include <time.h>
  45 #else
  46 # if HAVE_SYS_TIME_H
  47 #  include <sys/time.h>
  48 # else
  49 #  include <time.h>
  50 # endif
  51 #endif
  52 #ifdef HAVE_SYSCALL_H
  53 # include <syscall.h>
  54 #else
  55 # if HAVE_SYS_SYSCALL_H
  56 #  include <sys/syscall.h>
  57 # endif
  58 #endif
  59
  60 #include <sys/wait.h>
  61 #include <string.h>
  62 #include <limits.h>
  63 #include <libcitadel.h>
  64 #include "citadel.h"
  65 #include "server.h"
  66 #include "citserver.h"
  67 #include "support.h"
  68 #include "config.h"
  69 #include "user_ops.h"
  70 #include "database.h"
  71 #include "msgbase.h"
  72 #include "internet_addressing.h"
  73 #include "serv_network.h"
  74 #include "clientsocket.h"
  75 #include "file_ops.h"
  76 #include "citadel_dirs.h"
  77 #include "threads.h"
  78 #include "context.h"
  79 #include "netconfig.h"
  80 #include "netspool.h"
  81 #include "ctdl_module.h"
  82
  83
  84
  85 void DeleteNodeConf(void *vNode)
  86 {
  87         NodeConf *Node = (NodeConf*) vNode;
  88         FreeStrBuf(&Node->NodeName);
  89         FreeStrBuf(&Node->Secret);
  90         FreeStrBuf(&Node->Host);
  91         FreeStrBuf(&Node->Port);
  92         free(Node);
  93 }
  94
  95 NodeConf *NewNode(StrBuf *SerializedNode)
  96 {
  97         const char *Pos = NULL;
  98         NodeConf *Node;
  99
 100         /* we need at least 4 pipes and some other text so its invalid. */
 101         if (StrLength(SerializedNode) < 8)
 102                 return NULL;
 103         Node = (NodeConf *) malloc(sizeof(NodeConf));
 104
 105         Node->DeleteMe = 0;
 106
 107         Node->NodeName=NewStrBuf();
 108         StrBufExtract_NextToken(Node->NodeName, SerializedNode, &Pos, '|');
 109
 110         Node->Secret=NewStrBuf();
 111         StrBufExtract_NextToken(Node->Secret, SerializedNode, &Pos, '|');
 112
 113         Node->Host=NewStrBuf();
 114         StrBufExtract_NextToken(Node->Host, SerializedNode, &Pos, '|');
 115
 116         Node->Port=NewStrBuf();
 117         StrBufExtract_NextToken(Node->Port, SerializedNode, &Pos, '|');
 118         return Node;
 119 }
 120
 121
 122 /*
 123  * Load or refresh the Citadel network (IGnet) configuration for this node.
 124  */
 125 HashList* load_ignetcfg(void)
 126 {
 127         const char *LinePos;
 128         char       *Cfg;
 129         StrBuf     *Buf;
 130         StrBuf     *LineBuf;
 131         HashList   *Hash;
 132         NodeConf   *Node;
 133
 134         Cfg =  CtdlGetSysConfig(IGNETCFG);
 135         if ((Cfg == NULL) || IsEmptyStr(Cfg)) {
 136                 if (Cfg != NULL)
 137                         free(Cfg);
 138                 return NULL;
 139         }
 140
 141         Hash = NewHash(1, NULL);
 142         Buf = NewStrBufPlain(Cfg, -1);
 143         free(Cfg);
 144         LineBuf = NewStrBufPlain(NULL, StrLength(Buf));
 145         LinePos = NULL;
 146         do
 147         {
 148                 StrBufSipLine(LineBuf, Buf, &LinePos);
 149                 if (StrLength(LineBuf) != 0) {
 150                         Node = NewNode(LineBuf);
 151                         if (Node != NULL) {
 152                                 Put(Hash, SKEY(Node->NodeName), Node, DeleteNodeConf);
 153                         }
 154                 }
 155         } while (LinePos != StrBufNOTNULL);
 156         FreeStrBuf(&Buf);
 157         FreeStrBuf(&LineBuf);
 158         return Hash;
 159 }
 160
 161 void DeleteNetMap(void *vNetMap)
 162 {
 163         NetMap *TheNetMap = (NetMap*) vNetMap;
 164         FreeStrBuf(&TheNetMap->NodeName);
 165         FreeStrBuf(&TheNetMap->NextHop);
 166         free(TheNetMap);
 167 }
 168
 169 NetMap *NewNetMap(StrBuf *SerializedNetMap)
 170 {
 171         const char *Pos = NULL;
 172         NetMap *NM;
 173
 174         /* we need at least 3 pipes and some other text so its invalid. */
 175         if (StrLength(SerializedNetMap) < 6)
 176                 return NULL;
 177         NM = (NetMap *) malloc(sizeof(NetMap));
 178
 179         NM->NodeName=NewStrBuf();
 180         StrBufExtract_NextToken(NM->NodeName, SerializedNetMap, &Pos, '|');
 181
 182         NM->lastcontact = StrBufExtractNext_long(SerializedNetMap, &Pos, '|');
 183
 184         NM->NextHop=NewStrBuf();
 185         StrBufExtract_NextToken(NM->NextHop, SerializedNetMap, &Pos, '|');
 186
 187         return NM;
 188 }
 189
 190 HashList* read_network_map(void)
 191 {
 192         const char *LinePos;
 193         char       *Cfg;
 194         StrBuf     *Buf;
 195         StrBuf     *LineBuf;
 196         HashList   *Hash;
 197         NetMap     *TheNetMap;
 198
 199         Cfg =  CtdlGetSysConfig(IGNETMAP);
 200         if ((Cfg == NULL) || IsEmptyStr(Cfg)) {
 201                 if (Cfg != NULL)
 202                         free(Cfg);
 203                 return NULL;
 204         }
 205
 206         Hash = NewHash(1, NULL);
 207         Buf = NewStrBufPlain(Cfg, -1);
 208         free(Cfg);
 209         LineBuf = NewStrBufPlain(NULL, StrLength(Buf));
 210         LinePos = NULL;
 211         while (StrBufSipLine(Buf, LineBuf, &LinePos))
 212         {
 213                 TheNetMap = NewNetMap(LineBuf);
 214                 if (TheNetMap != NULL) { /* TODO: is the NodeName Uniq? */
 215                         Put(Hash, SKEY(TheNetMap->NodeName), TheNetMap, DeleteNetMap);
 216                 }
 217         }
 218         FreeStrBuf(&Buf);
 219         FreeStrBuf(&LineBuf);
 220         return Hash;
 221 }
 222
 223 StrBuf *SerializeNetworkMap(HashList *Map)
 224 {
 225         void *vMap;
 226         const char *key;
 227         long len;
 228         StrBuf *Ret = NewStrBuf();
 229         HashPos *Pos = GetNewHashPos(Map, 0);
 230
 231         while (GetNextHashPos(Map, Pos, &len, &key, &vMap))
 232         {
 233                 NetMap *pMap = (NetMap*) vMap;
 234                 StrBufAppendBuf(Ret, pMap->NodeName, 0);
 235                 StrBufAppendBufPlain(Ret, HKEY("|"), 0);
 236
 237                 StrBufAppendPrintf(Ret, "%ld", pMap->lastcontact, 0);
 238                 StrBufAppendBufPlain(Ret, HKEY("|"), 0);
 239
 240                 StrBufAppendBuf(Ret, pMap->NextHop, 0);
 241                 StrBufAppendBufPlain(Ret, HKEY("\n"), 0);
 242         }
 243         DeleteHashPos(&Pos);
 244         return Ret;
 245 }
 246
 247
 248 /*
 249  * Learn topology from path fields
 250  */
 251 void network_learn_topology(char *node, char *path, HashList *the_netmap, int *netmap_changed)
 252 {
 253         NetMap *pNM = NULL;
 254         void *vptr;
 255         char nexthop[256];
 256         NetMap *nmptr;
 257
 258         if (GetHash(the_netmap, node, strlen(node), &vptr) &&
 259             (vptr != NULL))/* TODO: is the NodeName Uniq? */
 260         {
 261                 pNM = (NetMap*)vptr;
 262                 extract_token(nexthop, path, 0, '!', sizeof nexthop);
 263                 if (!strcmp(nexthop, ChrPtr(pNM->NextHop))) {
 264                         pNM->lastcontact = time(NULL);
 265                         (*netmap_changed) ++;
 266                         return;
 267                 }
 268         }
 269
 270         /* If we got here then it's not in the map, so add it. */
 271         nmptr = (NetMap *) malloc(sizeof (NetMap));
 272         nmptr->NodeName = NewStrBufPlain(node, -1);
 273         nmptr->lastcontact = time(NULL);
 274         nmptr->NextHop = NewStrBuf ();
 275         StrBufExtract_tokenFromStr(nmptr->NextHop, path, strlen(path), 0, '!');
 276         /* TODO: is the NodeName Uniq? */
 277         Put(the_netmap, SKEY(nmptr->NodeName), nmptr, DeleteNetMap);
 278         (*netmap_changed) ++;
 279 }
 280
 281
 282 /*
 283  * Check the network map and determine whether the supplied node name is
 284  * valid.  If it is not a neighbor node, supply the name of a neighbor node
 285  * which is the next hop.  If it *is* a neighbor node, we also fill in the
 286  * shared secret.
 287  */
 288 int is_valid_node(const StrBuf **nexthop,
 289                   const StrBuf **secret,
 290                   StrBuf *node,
 291                   HashList *IgnetCfg,
 292                   HashList *the_netmap)
 293 {
 294         void *vNetMap;
 295         void *vNodeConf;
 296         NodeConf *TheNode;
 297         NetMap *TheNetMap;
 298
 299         if (StrLength(node) == 0) {
 300                 return(-1);
 301         }
 302
 303         /*
 304          * First try the neighbor nodes
 305          */
 306         if (GetCount(IgnetCfg) == 0) {
 307                 syslog(LOG_INFO, "IgnetCfg is empty!\n");
 308                 if (nexthop != NULL) {
 309                         *nexthop = NULL;
 310                 }
 311                 return(-1);
 312         }
 313
 314         /* try to find a neigbour with the name 'node' */
 315         if (GetHash(IgnetCfg, SKEY(node), &vNodeConf) &&
 316             (vNodeConf != NULL))
 317         {
 318                 TheNode = (NodeConf*)vNodeConf;
 319                 if (secret != NULL)
 320                         *secret = TheNode->Secret;
 321                 return 0;               /* yup, it's a direct neighbor */
 322         }
 323
 324         /*
 325          * If we get to this point we have to see if we know the next hop
 326          *//* TODO: is the NodeName Uniq? */
 327         if ((GetCount(the_netmap) > 0) &&
 328             (GetHash(the_netmap, SKEY(node), &vNetMap)))
 329         {
 330                 TheNetMap = (NetMap*)vNetMap;
 331                 if (nexthop != NULL)
 332                         *nexthop = TheNetMap->NextHop;
 333                 return(0);
 334         }
 335
 336         /*
 337          * If we get to this point, the supplied node name is bogus.
 338          */
 339         syslog(LOG_ERR, "Invalid node name <%s>\n", ChrPtr(node));
 340         return(-1);
 341 }
 342
 343
 344 void cmd_gnet(char *argbuf)
 345 {
 346         char filename[PATH_MAX];
 347         char buf[SIZ];
 348         FILE *fp;
 349
 350
 351         if (!IsEmptyStr(argbuf))
 352         {
 353                 if (CtdlAccessCheck(ac_aide)) return;
 354                 if (strcmp(argbuf, FILE_MAILALIAS))
 355                 {
 356                         cprintf("%d No such file or directory\n",
 357                                 ERROR + INTERNAL_ERROR);
 358                         return;
 359                 }
 360                 safestrncpy(filename, file_mail_aliases, sizeof(filename));
 361                 cprintf("%d Settings for <%s>\n",
 362                         LISTING_FOLLOWS,
 363                         filename);
 364         }
 365         else
 366         {
 367                 if ( (CC->room.QRflags & QR_MAILBOX) && (CC->user.usernum == atol(CC->room.QRname)) ) {
 368                         /* users can edit the netconfigs for their own mailbox rooms */
 369                 }
 370                 else if (CtdlAccessCheck(ac_room_aide)) return;
 371
 372                 assoc_file_name(filename, sizeof filename, &CC->room, ctdl_netcfg_dir);
 373                 cprintf("%d Network settings for room #%ld <%s>\n",
 374                         LISTING_FOLLOWS,
 375                         CC->room.QRnumber, CC->room.QRname);
 376         }
 377
 378         fp = fopen(filename, "r");
 379         if (fp != NULL) {
 380                 while (fgets(buf, sizeof buf, fp) != NULL) {
 381                         buf[strlen(buf)-1] = 0;
 382                         cprintf("%s\n", buf);
 383                 }
 384                 fclose(fp);
 385         }
 386
 387         cprintf("000\n");
 388 }
 389
 390 #define nForceAliases 5
 391 const ConstStr ForceAliases[nForceAliases] = {
 392         {HKEY("bbs,")},
 393         {HKEY("root,")},
 394         {HKEY("Auto,")},
 395         {HKEY("postmaster,")},
 396         {HKEY("abuse,")}
 397 };
 398
 399 void cmd_snet(char *argbuf) {
 400         char tempfilename[PATH_MAX];
 401         char filename[PATH_MAX];
 402         int TmpFD;
 403         StrBuf *Line;
 404         struct stat StatBuf;
 405         long len;
 406         int rc;
 407         int IsMailAlias = 0;
 408         int MailAliasesFound[nForceAliases];
 409
 410         unbuffer_output();
 411
 412         if (!IsEmptyStr(argbuf))
 413         {
 414                 if (CtdlAccessCheck(ac_aide)) return;
 415                 if (strcmp(argbuf, FILE_MAILALIAS))
 416                 {
 417                         cprintf("%d No such file or directory\n",
 418                                 ERROR + INTERNAL_ERROR);
 419                         return;
 420                 }
 421                 len = safestrncpy(filename, file_mail_aliases, sizeof(filename));
 422                 memset(MailAliasesFound, 0, sizeof(MailAliasesFound));
 423                 memcpy(tempfilename, filename, len + 1);
 424                 IsMailAlias = 1;
 425         }
 426         else
 427         {
 428                 if ( (CC->room.QRflags & QR_MAILBOX) && (CC->user.usernum == atol(CC->room.QRname)) ) {
 429                         /* users can edit the netconfigs for their own mailbox rooms */
 430                 }
 431                 else if (CtdlAccessCheck(ac_room_aide)) return;
 432
 433                 len = assoc_file_name(filename, sizeof filename, &CC->room, ctdl_netcfg_dir);
 434                 memcpy(tempfilename, filename, len + 1);
 435         }
 436         memset(&StatBuf, 0, sizeof(struct stat));
 437         if ((stat(filename, &StatBuf)  == -1) || (StatBuf.st_size == 0))
 438                 StatBuf.st_size = 80; /* Not there or empty? guess 80 chars line. */
 439
 440         sprintf(tempfilename + len, ".%d", CC->cs_pid);
 441         errno = 0;
 442         TmpFD = open(tempfilename, O_CREAT|O_EXCL|O_RDWR, S_IRUSR|S_IWUSR);
 443
 444         if ((TmpFD > 0) && (errno == 0))
 445         {
 446                 char *tmp = malloc(StatBuf.st_size * 2);
 447                 memset(tmp, ' ', StatBuf.st_size * 2);
 448                 rc = write(TmpFD, tmp, StatBuf.st_size * 2);
 449                 free(tmp);
 450                 if ((rc <= 0) || (rc != StatBuf.st_size * 2))
 451                 {
 452                         close(TmpFD);
 453                         cprintf("%d Unable to allocate the space required for %s: %s\n",
 454                                 ERROR + INTERNAL_ERROR,
 455                                 tempfilename,
 456                                 strerror(errno));
 457                         unlink(tempfilename);
 458                         return;
 459                 }
 460                 lseek(TmpFD, SEEK_SET, 0);
 461         }
 462         else {
 463                 cprintf("%d Unable to allocate the space required for %s: %s\n",
 464                         ERROR + INTERNAL_ERROR,
 465                         tempfilename,
 466                         strerror(errno));
 467                 unlink(tempfilename);
 468                 return;
 469         }
 470         Line = NewStrBuf();
 471
 472         cprintf("%d %s\n", SEND_LISTING, tempfilename);
 473
 474         len = 0;
 475         while (rc = CtdlClientGetLine(Line),
 476                (rc >= 0))
 477         {
 478                 if ((rc == 3) && (strcmp(ChrPtr(Line), "000") == 0))
 479                         break;
 480                 if (IsMailAlias)
 481                 {
 482                         int i;
 483
 484                         for (i = 0; i < nForceAliases; i++)
 485                         {
 486                                 if ((!MailAliasesFound[i]) &&
 487                                     (strncmp(ForceAliases[i].Key,
 488                                              ChrPtr(Line),
 489                                              ForceAliases[i].len) == 0)
 490                                         )
 491                                     {
 492                                             MailAliasesFound[i] = 1;
 493                                             break;
 494                                     }
 495                         }
 496                 }
 497
 498                 StrBufAppendBufPlain(Line, HKEY("\n"), 0);
 499                 write(TmpFD, ChrPtr(Line), StrLength(Line));
 500                 len += StrLength(Line);
 501         }
 502         FreeStrBuf(&Line);
 503         ftruncate(TmpFD, len);
 504         close(TmpFD);
 505
 506         if (IsMailAlias)
 507         {
 508                 int i, state;
 509                 /*
 510                  * Sanity check whether all aliases required by the RFCs were set
 511                  * else bail out.
 512                  */
 513                 state = 1;
 514                 for (i = 0; i < nForceAliases; i++)
 515                 {
 516                         if (!MailAliasesFound[i])
 517                                 state = 0;
 518                 }
 519                 if (state == 0)
 520                 {
 521                         cprintf("%d won't do this - you're missing an RFC required alias.\n",
 522                                 ERROR + INTERNAL_ERROR);
 523                         unlink(tempfilename);
 524                         return;
 525                 }
 526         }
 527
 528         /* Now copy the temp file to its permanent location.
 529          * (We copy instead of link because they may be on different filesystems)
 530          */
 531         begin_critical_section(S_NETCONFIGS);
 532         rename(tempfilename, filename);
 533         end_critical_section(S_NETCONFIGS);
 534 }
 535
 536 /*
 537  * cmd_netp() - authenticate to the server as another Citadel node polling
 538  *            for network traffic
 539  */
 540 void cmd_netp(char *cmdbuf)
 541 {
 542         struct CitContext *CCC = CC;
 543         HashList *working_ignetcfg;
 544         char *node;
 545         StrBuf *NodeStr;
 546         long nodelen;
 547         int v;
 548         long lens[2];
 549         const char *strs[2];
 550
 551         const StrBuf *secret = NULL;
 552         const StrBuf *nexthop = NULL;
 553         char err_buf[SIZ] = "";
 554
 555         /* Authenticate */
 556         node = CCC->curr_user;
 557         nodelen = extract_token(CCC->curr_user, cmdbuf, 0, '|', sizeof CCC->curr_user);
 558         NodeStr = NewStrBufPlain(node, nodelen);
 559         /* load the IGnet Configuration to check node validity */
 560         working_ignetcfg = load_ignetcfg();
 561         v = is_valid_node(&nexthop, &secret, NodeStr, working_ignetcfg, NULL);
 562         if (v != 0) {
 563                 snprintf(err_buf, sizeof err_buf,
 564                         "An unknown Citadel server called \"%s\" attempted to connect from %s [%s].\n",
 565                         node, CCC->cs_host, CCC->cs_addr
 566                 );
 567                 syslog(LOG_WARNING, "%s", err_buf);
 568                 cprintf("%d authentication failed\n", ERROR + PASSWORD_REQUIRED);
 569
 570                 strs[0] = CCC->cs_addr;
 571                 lens[0] = strlen(CCC->cs_addr);
 572
 573                 strs[1] = "SRV_UNKNOWN";
 574                 lens[1] = sizeof("SRV_UNKNOWN" - 1);
 575
 576                 CtdlAideFPMessage(
 577                         err_buf,
 578                         "IGNet Networking.",
 579                         2, strs, (long*) &lens);
 580
 581                 DeleteHash(&working_ignetcfg);
 582                 FreeStrBuf(&NodeStr);
 583                 return;
 584         }
 585
 586         extract_token(CCC->user.password, cmdbuf, 1, '|', sizeof CCC->user.password);
 587         if (strcasecmp(CCC->user.password, ChrPtr(secret))) {
 588                 snprintf(err_buf, sizeof err_buf,
 589                         "A Citadel server at %s [%s] failed to authenticate as network node \"%s\".\n",
 590                         CCC->cs_host, CCC->cs_addr, node
 591                 );
 592                 syslog(LOG_WARNING, "%s", err_buf);
 593                 cprintf("%d authentication failed\n", ERROR + PASSWORD_REQUIRED);
 594
 595                 strs[0] = CCC->cs_addr;
 596                 lens[0] = strlen(CCC->cs_addr);
 597
 598                 strs[1] = "SRV_PW";
 599                 lens[1] = sizeof("SRV_PW" - 1);
 600
 601                 CtdlAideFPMessage(
 602                         err_buf,
 603                         "IGNet Networking.",
 604                         2, strs, (long*) &lens);
 605
 606                 DeleteHash(&working_ignetcfg);
 607                 FreeStrBuf(&NodeStr);
 608                 return;
 609         }
 610
 611         if (network_talking_to(node, nodelen, NTT_CHECK)) {
 612                 syslog(LOG_WARNING, "Duplicate session for network node <%s>", node);
 613                 cprintf("%d Already talking to %s right now\n", ERROR + RESOURCE_BUSY, node);
 614                 DeleteHash(&working_ignetcfg);
 615                 FreeStrBuf(&NodeStr);
 616                 return;
 617         }
 618         nodelen = safestrncpy(CCC->net_node, node, sizeof CCC->net_node);
 619         network_talking_to(CCC->net_node, nodelen, NTT_ADD);
 620         syslog(LOG_NOTICE, "Network node <%s> logged in from %s [%s]\n",
 621                 CCC->net_node, CCC->cs_host, CCC->cs_addr
 622         );
 623         cprintf("%d authenticated as network node '%s'\n", CIT_OK, CCC->net_node);
 624         DeleteHash(&working_ignetcfg);
 625         FreeStrBuf(&NodeStr);
 626 }
 627
 628 int netconfig_check_roomaccess(
 629         char *errmsgbuf,
 630         size_t n,
 631         const char* RemoteIdentifier)
 632 {
 633         SpoolControl *sc;
 634         char filename[SIZ];
 635         int found;
 636
 637         if (RemoteIdentifier == NULL)
 638         {
 639                 snprintf(errmsgbuf, n, "Need sender to permit access.");
 640                 return (ERROR + USERNAME_REQUIRED);
 641         }
 642
 643         assoc_file_name(filename, sizeof filename, &CC->room, ctdl_netcfg_dir);
 644         begin_critical_section(S_NETCONFIGS);
 645         if (!read_spoolcontrol_file(&sc, filename))
 646         {
 647                 end_critical_section(S_NETCONFIGS);
 648                 snprintf(errmsgbuf, n,
 649                          "This mailing list only accepts posts from subscribers.");
 650                 return (ERROR + NO_SUCH_USER);
 651         }
 652         end_critical_section(S_NETCONFIGS);
 653         found = is_recipient (sc, RemoteIdentifier);
 654         free_spoolcontrol_struct(&sc);
 655         if (found) {
 656                 return (0);
 657         }
 658         else {
 659                 snprintf(errmsgbuf, n,
 660                          "This mailing list only accepts posts from subscribers.");
 661                 return (ERROR + NO_SUCH_USER);
 662         }
 663 }
 664 /*
 665  * Module entry point
 666  */
 667 CTDL_MODULE_INIT(netconfig)
 668 {
 669         if (!threading)
 670         {
 671                 CtdlRegisterProtoHook(cmd_gnet, "GNET", "Get network config");
 672                 CtdlRegisterProtoHook(cmd_snet, "SNET", "Set network config");
 673                 CtdlRegisterProtoHook(cmd_netp, "NETP", "Identify as network poller");
 674         }
 675         return "netconfig";
 676 }