citadel/modules/jabber/serv_xmpp.c

   1 /*
   2  * $Id:  $
   3  *
   4  * XMPP (Jabber) service for the Citadel system
   5  * Copyright (c) 2007 by Art Cancro
   6  * This code is released under the terms of the GNU General Public License.
   7  *
   8  */
   9
  10 #include "sysdep.h"
  11 #include <stdlib.h>
  12 #include <unistd.h>
  13 #include <stdio.h>
  14 #include <fcntl.h>
  15 #include <signal.h>
  16 #include <pwd.h>
  17 #include <errno.h>
  18 #include <sys/types.h>
  19
  20 #if TIME_WITH_SYS_TIME
  21 # include <sys/time.h>
  22 # include <time.h>
  23 #else
  24 # if HAVE_SYS_TIME_H
  25 #  include <sys/time.h>
  26 # else
  27 #  include <time.h>
  28 # endif
  29 #endif
  30
  31 #include <sys/wait.h>
  32 #include <string.h>
  33 #include <limits.h>
  34 #include <ctype.h>
  35 #include <libcitadel.h>
  36 #include "citadel.h"
  37 #include "server.h"
  38 #include "citserver.h"
  39 #include "support.h"
  40 #include "config.h"
  41 #include "room_ops.h"
  42 #include "user_ops.h"
  43 #include "policy.h"
  44 #include "database.h"
  45 #include "msgbase.h"
  46 #include "internet_addressing.h"
  47 #include "md5.h"
  48 #include "ctdl_module.h"
  49
  50 #ifdef HAVE_EXPAT
  51 #include <expat.h>
  52 #include "serv_xmpp.h"
  53
  54
  55 /* We have just received a <stream> tag from the client, so send them ours */
  56
  57 void xmpp_stream_start(void *data, const char *supplied_el, const char **attr)
  58 {
  59
  60         lprintf(CTDL_DEBUG, "New stream detected.\n");
  61
  62         while (*attr) {
  63                 if (!strcasecmp(attr[0], "to")) {
  64                         safestrncpy(XMPP->server_name, attr[1], sizeof XMPP->server_name);
  65                 }
  66                 attr += 2;
  67         }
  68
  69         cprintf("<?xml version=\"1.0\" encoding=\"UTF-8\"?>");
  70
  71         cprintf("<stream:stream ");
  72         cprintf("from=\"%s\" ", XMPP->server_name);
  73         cprintf("id=\"%08x\" ", CC->cs_pid);
  74         cprintf("version=\"1.0\" ");
  75         cprintf("xmlns:stream=\"http://etherx.jabber.org/streams\" ");
  76         cprintf("xmlns=\"jabber:client\">");
  77
  78         /* The features of this stream are... */
  79         cprintf("<stream:features>");
  80
  81         /* Binding... */
  82         cprintf("<bind xmlns=\"urn:ietf:params:xml:ns:xmpp-bind\"/>");
  83
  84         /* Sessions... */
  85         cprintf("<session xmlns=\"urn:ietf:params:xml:ns:xmpp-session\"/>");
  86
  87         /* SASL (but only if we're not already logged in; this is important!) ... */
  88         if (!CC->logged_in) {
  89                 xmpp_output_auth_mechs();
  90         }
  91
  92         /* ...and the ability to close XML tags using angle brackets.  We should patent this. */
  93         cprintf("</stream:features>");
  94 }
  95
  96
  97 void xmpp_xml_start(void *data, const char *supplied_el, const char **attr) {
  98         char el[256];
  99         char *sep = NULL;
 100         int i;
 101
 102         /* Axe the namespace, we don't care about it */
 103         safestrncpy(el, supplied_el, sizeof el);
 104         while (sep = strchr(el, ':'), sep) {
 105                 strcpy(el, ++sep);
 106         }
 107
 108         lprintf(CTDL_DEBUG, "XMPP ELEMENT START: <%s>\n", el);
 109
 110         for (i=0; attr[i] != NULL; i+=2) {
 111                 lprintf(CTDL_DEBUG, "                    Attribute '%s' = '%s'\n", attr[i], attr[i+1]);
 112         }
 113
 114         if (!strcasecmp(el, "stream")) {
 115                 xmpp_stream_start(data, supplied_el, attr);
 116         }
 117
 118         else if (!strcasecmp(el, "query")) {
 119                 XMPP->iq_query_xmlns[0] = 0;
 120                 safestrncpy(XMPP->iq_query_xmlns, supplied_el, sizeof XMPP->iq_query_xmlns);
 121         }
 122
 123         else if (!strcasecmp(el, "iq")) {
 124                 for (i=0; attr[i] != NULL; i+=2) {
 125                         if (!strcasecmp(attr[i], "type")) {
 126                                 safestrncpy(XMPP->iq_type, attr[i+1], sizeof XMPP->iq_type);
 127                         }
 128                         else if (!strcasecmp(attr[i], "id")) {
 129                                 safestrncpy(XMPP->iq_id, attr[i+1], sizeof XMPP->iq_id);
 130                         }
 131                         else if (!strcasecmp(attr[i], "from")) {
 132                                 safestrncpy(XMPP->iq_from, attr[i+1], sizeof XMPP->iq_from);
 133                         }
 134                         else if (!strcasecmp(attr[i], "to")) {
 135                                 safestrncpy(XMPP->iq_to, attr[i+1], sizeof XMPP->iq_to);
 136                         }
 137                 }
 138         }
 139
 140         else if (!strcasecmp(el, "auth")) {
 141                 XMPP->sasl_auth_mech[0] = 0;
 142                 for (i=0; attr[i] != NULL; i+=2) {
 143                         if (!strcasecmp(attr[i], "mechanism")) {
 144                                 safestrncpy(XMPP->sasl_auth_mech, attr[i+1], sizeof XMPP->sasl_auth_mech);
 145                         }
 146                 }
 147         }
 148 }
 149
 150
 151
 152 void xmpp_xml_end(void *data, const char *supplied_el) {
 153         char el[256];
 154         char *sep = NULL;
 155
 156         /* Axe the namespace, we don't care about it */
 157         safestrncpy(el, supplied_el, sizeof el);
 158         while (sep = strchr(el, ':'), sep) {
 159                 strcpy(el, ++sep);
 160         }
 161
 162         lprintf(CTDL_DEBUG, "XMPP ELEMENT END  : <%s>\n", el);
 163         if (XMPP->chardata_len > 0) {
 164                 lprintf(CTDL_DEBUG, "          chardata: %s\n", XMPP->chardata);
 165         }
 166
 167         if (!strcasecmp(el, "resource")) {
 168                 if (XMPP->chardata_len > 0) {
 169                         safestrncpy(XMPP->iq_client_resource, XMPP->chardata,
 170                                 sizeof XMPP->iq_client_resource);
 171                 }
 172         }
 173
 174         else if (!strcasecmp(el, "iq")) {
 175
 176                 /*
 177                  * iq type="get" (handle queries)
 178                  */
 179                 if (!strcasecmp(XMPP->iq_type, "get")) {
 180
 181                         /*
 182                          * Query on a namespace
 183                          */
 184                         if (!IsEmptyStr(XMPP->iq_query_xmlns)) {
 185                                 xmpp_query_namespace(XMPP->iq_id, XMPP->iq_from,
 186                                                 XMPP->iq_to, XMPP->iq_query_xmlns);
 187                         }
 188
 189                         /*
 190                          * Unknown queries ... return the XML equivalent of a blank stare
 191                          */
 192                         else {
 193                                 cprintf("<iq type=\"result\" id=\"%s\">", XMPP->iq_id);
 194                                 cprintf("</iq>");
 195                         }
 196                 }
 197
 198                 /*
 199                  * If this <iq> stanza was a "bind" attempt, process it ...
 200                  */
 201                 else if ( (!IsEmptyStr(XMPP->iq_id)) && (!IsEmptyStr(XMPP->iq_client_resource)) ) {
 202
 203                         /* Generate the "full JID" of the client resource */
 204
 205                         snprintf(XMPP->client_jid, sizeof XMPP->client_jid,
 206                                 "%d@%s/%s",
 207                                 CC->cs_pid,
 208                                 config.c_fqdn,
 209                                 XMPP->iq_client_resource
 210                         );
 211
 212                         /* Tell the client what its JID is */
 213
 214                         cprintf("<iq type=\"result\" id=\"%s\">", XMPP->iq_id);
 215                         cprintf("<bind xmlns=\"urn:ietf:params:xml:ns:xmpp-bind\">");
 216                         cprintf("<jid>%s</jid>", XMPP->client_jid);
 217                         cprintf("</bind>");
 218                         cprintf("</iq>");
 219                 }
 220
 221                 else if (XMPP->iq_session) {
 222                         cprintf("<iq type=\"result\" id=\"%s\">", XMPP->iq_id);
 223                         cprintf("</iq>");
 224                 }
 225
 226                 else {
 227                         cprintf("<iq type=\"error\" id=\"%s\">", XMPP->iq_id);
 228                         cprintf("<error></error>");
 229                         cprintf("</iq>");
 230                 }
 231
 232                 /* Now clear these fields out so they don't get used by a future stanza */
 233                 XMPP->iq_id[0] = 0;
 234                 XMPP->iq_from[0] = 0;
 235                 XMPP->iq_to[0] = 0;
 236                 XMPP->iq_type[0] = 0;
 237                 XMPP->iq_client_resource[0] = 0;
 238                 XMPP->iq_session = 0;
 239                 XMPP->iq_query_xmlns[0] = 0;
 240         }
 241
 242         else if (!strcasecmp(el, "auth")) {
 243
 244                 /* Try to authenticate (this function is responsible for the output stanza) */
 245                 xmpp_sasl_auth(XMPP->sasl_auth_mech, (XMPP->chardata != NULL ? XMPP->chardata : "") );
 246
 247                 /* Now clear these fields out so they don't get used by a future stanza */
 248                 XMPP->sasl_auth_mech[0] = 0;
 249         }
 250
 251         else if (!strcasecmp(el, "session")) {
 252                 XMPP->iq_session = 1;
 253         }
 254
 255         XMPP->chardata_len = 0;
 256         if (XMPP->chardata_alloc > 0) {
 257                 XMPP->chardata[0] = 0;
 258         }
 259 }
 260
 261
 262 void xmpp_xml_chardata(void *data, const XML_Char *s, int len)
 263 {
 264         struct citxmpp *X = XMPP;
 265
 266         if (X->chardata_alloc == 0) {
 267                 X->chardata_alloc = SIZ;
 268                 X->chardata = malloc(X->chardata_alloc);
 269         }
 270         if ((X->chardata_len + len + 1) > X->chardata_alloc) {
 271                 X->chardata_alloc = X->chardata_len + len + 1024;
 272                 X->chardata = realloc(X->chardata, X->chardata_alloc);
 273         }
 274         memcpy(&X->chardata[X->chardata_len], s, len);
 275         X->chardata_len += len;
 276         X->chardata[X->chardata_len] = 0;
 277 }
 278
 279
 280 /*
 281  * This cleanup function blows away the temporary memory and files used by the XMPP service.
 282  */
 283 void xmpp_cleanup_function(void) {
 284
 285         /* Don't do this stuff if this is not a XMPP session! */
 286         if (CC->h_command_function != xmpp_command_loop) return;
 287
 288         lprintf(CTDL_DEBUG, "Performing XMPP cleanup hook\n");
 289         if (XMPP->chardata != NULL) {
 290                 free(XMPP->chardata);
 291                 XMPP->chardata = NULL;
 292                 XMPP->chardata_len = 0;
 293                 XMPP->chardata_alloc = 0;
 294         }
 295         XML_ParserFree(XMPP->xp);
 296         free(XMPP);
 297 }
 298
 299
 300
 301 /*
 302  * Here's where our XMPP session begins its happy day.
 303  */
 304 void xmpp_greeting(void) {
 305         strcpy(CC->cs_clientname, "Jabber session");
 306         CC->session_specific_data = malloc(sizeof(struct citxmpp));
 307         memset(XMPP, 0, sizeof(struct citxmpp));
 308
 309         /* XMPP does not use a greeting, but we still have to initialize some things. */
 310
 311         XMPP->xp = XML_ParserCreateNS("UTF-8", ':');
 312         if (XMPP->xp == NULL) {
 313                 lprintf(CTDL_ALERT, "Cannot create XML parser!\n");
 314                 CC->kill_me = 1;
 315                 return;
 316         }
 317
 318         XML_SetElementHandler(XMPP->xp, xmpp_xml_start, xmpp_xml_end);
 319         XML_SetCharacterDataHandler(XMPP->xp, xmpp_xml_chardata);
 320         // XML_SetUserData(XMPP->xp, something...);
 321 }
 322
 323
 324 /*
 325  * Main command loop for XMPP sessions.
 326  */
 327 void xmpp_command_loop(void) {
 328         char cmdbuf[16];
 329         int retval;
 330
 331         time(&CC->lastcmd);
 332         memset(cmdbuf, 0, sizeof cmdbuf); /* Clear it, just in case */
 333         retval = client_read(cmdbuf, 1);
 334         if (retval != 1) {
 335                 lprintf(CTDL_ERR, "Client disconnected: ending session.\r\n");
 336                 CC->kill_me = 1;
 337                 return;
 338         }
 339
 340         /* FIXME ... this is woefully inefficient. */
 341
 342         XML_Parse(XMPP->xp, cmdbuf, 1, 0);
 343 }
 344
 345 const char *CitadelServiceXMPP="XMPP";
 346
 347 #endif  /* HAVE_EXPAT */
 348
 349 CTDL_MODULE_INIT(jabber)
 350 {
 351 #ifdef HAVE_EXPAT
 352         if (!threading) {
 353                 /* CtdlRegisterServiceHook(config.c_xmpp_port,          FIXME   */
 354                 CtdlRegisterServiceHook(5222,
 355                                         NULL,
 356                                         xmpp_greeting,
 357                                         xmpp_command_loop,
 358                                         NULL,
 359                                         CitadelServiceXMPP);
 360                 CtdlRegisterSessionHook(xmpp_cleanup_function, EVT_STOP);
 361         #else
 362                 lprintf(CTDL_INFO, "This server is missing the Expat XML parser.  Jabber service will be disabled.\n");
 363 #endif
 364         }
 365
 366         /* return our Subversion id for the Log */
 367         return "$Id: $";
 368 }