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], "to")) {
 132                                 safestrncpy(XMPP->iq_to, attr[i+1], sizeof XMPP->iq_to);
 133                         }
 134                 }
 135         }
 136
 137         else if (!strcasecmp(el, "auth")) {
 138                 XMPP->sasl_auth_mech[0] = 0;
 139                 for (i=0; attr[i] != NULL; i+=2) {
 140                         if (!strcasecmp(attr[i], "mechanism")) {
 141                                 safestrncpy(XMPP->sasl_auth_mech, attr[i+1], sizeof XMPP->sasl_auth_mech);
 142                         }
 143                 }
 144         }
 145 }
 146
 147
 148
 149 void xmpp_xml_end(void *data, const char *supplied_el) {
 150         char el[256];
 151         char *sep = NULL;
 152
 153         /* Axe the namespace, we don't care about it */
 154         safestrncpy(el, supplied_el, sizeof el);
 155         while (sep = strchr(el, ':'), sep) {
 156                 strcpy(el, ++sep);
 157         }
 158
 159         lprintf(CTDL_DEBUG, "XMPP ELEMENT END  : <%s>\n", el);
 160         if (XMPP->chardata_len > 0) {
 161                 lprintf(CTDL_DEBUG, "          chardata: %s\n", XMPP->chardata);
 162         }
 163
 164         if (!strcasecmp(el, "resource")) {
 165                 if (XMPP->chardata_len > 0) {
 166                         safestrncpy(XMPP->iq_client_resource, XMPP->chardata,
 167                                 sizeof XMPP->iq_client_resource);
 168                 }
 169         }
 170
 171         else if (!strcasecmp(el, "iq")) {
 172
 173                 /*
 174                  * iq type="get" (handle queries)
 175                  */
 176                 if (!strcasecmp(XMPP->iq_type, "get")) {
 177
 178                         /*
 179                          * Query on a namespace
 180                          */
 181                         if (!IsEmptyStr(XMPP->iq_query_xmlns)) {
 182                                 xmpp_query_namespace(XMPP->iq_id, XMPP->iq_to, XMPP->iq_query_xmlns);
 183                         }
 184
 185                         /*
 186                          * Unknown queries ... return the XML equivalent of a blank stare
 187                          */
 188                         else {
 189                                 cprintf("<iq type=\"result\" id=\"%s\">", XMPP->iq_id);
 190                                 cprintf("</iq>");
 191                         }
 192                 }
 193
 194                 /*
 195                  * If this <iq> stanza was a "bind" attempt, process it ...
 196                  */
 197                 else if ( (!IsEmptyStr(XMPP->iq_id)) && (!IsEmptyStr(XMPP->iq_client_resource)) ) {
 198
 199                         /* Generate the "full JID" of the client resource */
 200
 201                         snprintf(XMPP->client_jid, sizeof XMPP->client_jid,
 202                                 "%d@%s/%s",
 203                                 CC->cs_pid,
 204                                 config.c_fqdn,
 205                                 XMPP->iq_client_resource
 206                         );
 207
 208                         /* Tell the client what its JID is */
 209
 210                         cprintf("<iq type=\"result\" id=\"%s\">", XMPP->iq_id);
 211                         cprintf("<bind xmlns=\"urn:ietf:params:xml:ns:xmpp-bind\">");
 212                         cprintf("<jid>%s</jid>", XMPP->client_jid);
 213                         cprintf("</bind>");
 214                         cprintf("</iq>");
 215                 }
 216
 217                 else if (XMPP->iq_session) {
 218                         cprintf("<iq type=\"result\" id=\"%s\">", XMPP->iq_id);
 219                         cprintf("</iq>");
 220                 }
 221
 222                 else {
 223                         cprintf("<iq type=\"error\" id=\"%s\">", XMPP->iq_id);
 224                         cprintf("<error></error>");
 225                         cprintf("</iq>");
 226                 }
 227
 228                 /* Now clear these fields out so they don't get used by a future stanza */
 229                 XMPP->iq_id[0] = 0;
 230                 XMPP->iq_to[0] = 0;
 231                 XMPP->iq_type[0] = 0;
 232                 XMPP->iq_client_resource[0] = 0;
 233                 XMPP->iq_session = 0;
 234                 XMPP->iq_query_xmlns[0] = 0;
 235         }
 236
 237         else if (!strcasecmp(el, "auth")) {
 238
 239                 /* Try to authenticate (this function is responsible for the output stanza) */
 240                 xmpp_sasl_auth(XMPP->sasl_auth_mech, (XMPP->chardata != NULL ? XMPP->chardata : "") );
 241
 242                 /* Now clear these fields out so they don't get used by a future stanza */
 243                 XMPP->sasl_auth_mech[0] = 0;
 244         }
 245
 246         else if (!strcasecmp(el, "session")) {
 247                 XMPP->iq_session = 1;
 248         }
 249
 250         XMPP->chardata_len = 0;
 251         if (XMPP->chardata_alloc > 0) {
 252                 XMPP->chardata[0] = 0;
 253         }
 254 }
 255
 256
 257 void xmpp_xml_chardata(void *data, const XML_Char *s, int len)
 258 {
 259         struct citxmpp *X = XMPP;
 260
 261         if (X->chardata_alloc == 0) {
 262                 X->chardata_alloc = SIZ;
 263                 X->chardata = malloc(X->chardata_alloc);
 264         }
 265         if ((X->chardata_len + len + 1) > X->chardata_alloc) {
 266                 X->chardata_alloc = X->chardata_len + len + 1024;
 267                 X->chardata = realloc(X->chardata, X->chardata_alloc);
 268         }
 269         memcpy(&X->chardata[X->chardata_len], s, len);
 270         X->chardata_len += len;
 271         X->chardata[X->chardata_len] = 0;
 272 }
 273
 274
 275 /*
 276  * This cleanup function blows away the temporary memory and files used by the XMPP service.
 277  */
 278 void xmpp_cleanup_function(void) {
 279
 280         /* Don't do this stuff if this is not a XMPP session! */
 281         if (CC->h_command_function != xmpp_command_loop) return;
 282
 283         lprintf(CTDL_DEBUG, "Performing XMPP cleanup hook\n");
 284         if (XMPP->chardata != NULL) {
 285                 free(XMPP->chardata);
 286                 XMPP->chardata = NULL;
 287                 XMPP->chardata_len = 0;
 288                 XMPP->chardata_alloc = 0;
 289         }
 290         XML_ParserFree(XMPP->xp);
 291         free(XMPP);
 292 }
 293
 294
 295
 296 /*
 297  * Here's where our XMPP session begins its happy day.
 298  */
 299 void xmpp_greeting(void) {
 300         strcpy(CC->cs_clientname, "Jabber session");
 301         CC->session_specific_data = malloc(sizeof(struct citxmpp));
 302         memset(XMPP, 0, sizeof(struct citxmpp));
 303
 304         /* XMPP does not use a greeting, but we still have to initialize some things. */
 305
 306         XMPP->xp = XML_ParserCreateNS("UTF-8", ':');
 307         if (XMPP->xp == NULL) {
 308                 lprintf(CTDL_ALERT, "Cannot create XML parser!\n");
 309                 CC->kill_me = 1;
 310                 return;
 311         }
 312
 313         XML_SetElementHandler(XMPP->xp, xmpp_xml_start, xmpp_xml_end);
 314         XML_SetCharacterDataHandler(XMPP->xp, xmpp_xml_chardata);
 315         // XML_SetUserData(XMPP->xp, something...);
 316 }
 317
 318
 319 /*
 320  * Main command loop for XMPP sessions.
 321  */
 322 void xmpp_command_loop(void) {
 323         char cmdbuf[16];
 324         int retval;
 325
 326         time(&CC->lastcmd);
 327         memset(cmdbuf, 0, sizeof cmdbuf); /* Clear it, just in case */
 328         retval = client_read(cmdbuf, 1);
 329         if (retval != 1) {
 330                 lprintf(CTDL_ERR, "Client disconnected: ending session.\r\n");
 331                 CC->kill_me = 1;
 332                 return;
 333         }
 334
 335         /* FIXME ... this is woefully inefficient. */
 336
 337         XML_Parse(XMPP->xp, cmdbuf, 1, 0);
 338 }
 339
 340 const char *CitadelServiceXMPP="XMPP";
 341
 342 #endif  /* HAVE_EXPAT */
 343
 344 CTDL_MODULE_INIT(jabber)
 345 {
 346 #ifdef HAVE_EXPAT
 347         if (!threading) {
 348                 /* CtdlRegisterServiceHook(config.c_xmpp_port,          FIXME   */
 349                 CtdlRegisterServiceHook(5222,
 350                                         NULL,
 351                                         xmpp_greeting,
 352                                         xmpp_command_loop,
 353                                         NULL,
 354                                         CitadelServiceXMPP);
 355                 CtdlRegisterSessionHook(xmpp_cleanup_function, EVT_STOP);
 356         #else
 357                 lprintf(CTDL_INFO, "This server is missing the Expat XML parser.  Jabber service will be disabled.\n");
 358 #endif
 359         }
 360
 361         /* return our Subversion id for the Log */
 362         return "$Id: $";
 363 }