/* This file is part of the Project Athena Zephyr Notification System.
 * It contains functions for managing subscription lists.
 *
 *	Created by:	John T. Kohl
 *
 *	$Source$
 *	$Author$
 *
 *	Copyright (c) 1987,1988 by the Massachusetts Institute of Technology.
 *	For copying and distribution information, see the file
 *	"mit-copyright.h".
 */

#include <zephyr/mit-copyright.h>
#include "zserver.h"

#ifndef lint
#ifndef SABER
static const char rcsid_subscr_c[] = "$Id: b788663061783fb37d46ee7bc8d034cc288152b7 $";
#endif
#endif

#ifndef INADDR_NONE
#define INADDR_NONE 0xffffffff
#endif

/*
 * The subscription manager.
 *
 * External functions:
 *
 * Code_t subscr_subscribe(who, notice)
 *	Client *who;
 *	ZNotice_t *notice;
 *
 * Code_t subscr_cancel(sin, notice)
 *	struct sockaddr_in *sin;
 *	ZNotice_t *notice;
 *
 * Code_t subscr_cancel_client(client)
 *	Client *client;
 *
 * Code_t subscr_cancel_host(addr)
 *	struct in_addr *addr;
 *
 * Client *subscr_match_list(notice)
 *	ZNotice_t *notice;
 *
 * void subscr_free_list(list)
 *	Client *list;
 *
 * void subscr_sendlist(notice, auth, who)
 *	ZNotice_t *notice;
 *	int auth;
 *	struct sockaddr_in *who;
 *
 * Code_t subscr_send_subs(client, vers)
 *	Client *client;
 *	char *vers;
 *
 * Code_t subscr_def_subs(who)
 *	Client *who;
 *
 * void subscr_reset();
 *
 */

#if defined(HAVE_KRB4)
C_Block	serv_key;
Sched	serv_ksched;
#endif

static Code_t add_subscriptions(Client *who, Destlist *subs_queue,
				ZNotice_t *notice, Server *server);
static Destlist *extract_subscriptions(ZNotice_t *notice);
static void free_subscriptions(Destlist *subs);
static void free_subscription(Destlist *sub);
static char **subscr_marshal_subs(ZNotice_t *notice, int auth,
				  struct sockaddr_in *who,
				  int *found);
static Destlist *subscr_copy_def_subs(char *person);
static Code_t subscr_realm_sendit(Client *who, Destlist *subs,
				  ZNotice_t *notice, ZRealm *realm);
static void subscr_unsub_sendit(Client *who, Destlist *subs,
				ZRealm *realm);

static int defaults_read = 0;		/* set to 1 if the default subs
					   are in memory */
static ZNotice_t default_notice;	/* contains default subscriptions */

String *wildcard_instance;
String *empty;

/* WARNING: make sure this is the same as the number of strings you */
/* plan to hand back to the user in response to a subscription check, */
/* else you will lose.  See subscr_sendlist() */
#define	NUM_FIELDS	3

/*
 * subscribe the client to types described in notice.
 */

Code_t
subscr_subscribe(Client *who,
		 ZNotice_t *notice,
		 Server *server)
{
    Destlist *subs;

    subs = extract_subscriptions(notice);
    return add_subscriptions(who, subs, notice, server);
}

static Code_t
add_subscriptions(Client *who,
		  Destlist *subs,
		  ZNotice_t *notice,
		  Server *server)
{
    Destlist *next;
    Code_t retval;
    Acl *acl;
    String *sender;
    ZRealm *realm = NULL;

    if (!subs)
	return ZERR_NONE;	/* no subscr -> no error */

    sender = make_string(notice->z_sender, 0);

    /* Loop over the new subscriptions. */
    for (; subs; subs = next) {
	next = subs->next;
	/* check the recipient for a realm which isn't ours */
	realm = NULL;
	if (subs->dest.recip->string[0] == '@' &&
	    strcmp((subs->dest.recip->string + 1), ZGetRealm()) != 0)
	    realm = realm_get_realm_by_name(subs->dest.recip->string + 1);
	if (!bdumping) {
	    if (subs->dest.recip != empty && subs->dest.recip != sender
		&& subs->dest.recip->string[0] != '@') {
		syslog(LOG_WARNING, "subscr unauth %s recipient %s",
		       sender->string, subs->dest.recip->string);
		free_subscription(subs); /* free this one - denied */
		continue; /* the for loop */
	    }
	    acl = class_get_acl(subs->dest.classname);
	    if (acl && !realm) {
		if (!access_check(sender->string, &who->addr, acl, SUBSCRIBE)) {
		    syslog(LOG_WARNING, "subscr unauth %s class %s",
			   sender->string, subs->dest.classname->string);
		    free_subscription(subs); /* free this one - denied */
		    continue; /* the for loop */
		}
		if (wildcard_instance == subs->dest.inst) {
		    if (!access_check(sender->string, &who->addr, acl, INSTWILD)) {
			syslog(LOG_WARNING,
			       "subscr unauth %s class %s wild inst",
			       sender->string, subs->dest.classname->string);
			free_subscription(subs); /* free this one - denied */
			continue; /* the for loop */
		    }
		}
	    }
	}
	if (realm && !bdumping) {
	    retval = subscr_realm_sendit(who, subs, notice, realm);
	    if (retval != ZERR_NONE) {
		free_subscription(subs);
		continue; /* the for loop */
	    } else {
		free_subscription(subs); /* free this one, wil get from
						ADD */
	    }
	} else {
	  retval = triplet_register(who, &subs->dest, NULL);
	  if (retval != ZERR_NONE) {
	      if (retval == ZSRV_CLASSXISTS) {
		  free_subscription(subs); /* free this one */
	      } else {
		  free_subscriptions(subs);
		  free_string(sender);
		  return retval;
	      }
	  } else {
	      /* If realm, let the REALM_ADD_SUBSCRIBE do insertion */
	      Destlist_insert(&who->subs, subs);
	  }
	}
    }

    free_string(sender);
    return ZERR_NONE;
}

/*
 * add default subscriptions to the client's subscription chain.
 */

Code_t
subscr_def_subs(Client *who)
{
    Destlist *subs;

    subs = subscr_copy_def_subs(who->principal->string);
    return add_subscriptions(who, subs, &default_notice, NULL);
}

void
subscr_reset(void)
{
    free(default_notice.z_message);
    default_notice.z_message = NULL;
    defaults_read = 0;
}

static Destlist *
subscr_copy_def_subs(char *person)
{
    int retval, fd;
    struct stat statbuf;
    char *def_sub_area, *cp;
    Destlist *subs, *sub;

    if (!defaults_read) {
	fd = open(subs_file, O_RDONLY, 0666);
	if (fd < 0) {
	    syslog(LOG_ERR, "can't open %s:%m", subs_file);
	    return NULL;
	}
	retval = fstat(fd, &statbuf);
	if (retval < 0) {
	    syslog(LOG_ERR, "fstat failure on %s:%m", subs_file);
	    close(fd);
	    return NULL;
	}
	def_sub_area = (char *) malloc(statbuf.st_size + 1);
	if (!def_sub_area) {
	    syslog(LOG_ERR, "no mem copy_def_subs");
	    close(fd);
	    return NULL;
	}
	retval = read(fd, def_sub_area, (size_t) statbuf.st_size);
	if (retval != statbuf.st_size) {
	    syslog(LOG_ERR, "short read in copy_def_subs");
	    close(fd);
	    return NULL;
	}

	close(fd);
	def_sub_area[statbuf.st_size] = '\0'; /* null-terminate it */

	/*
	   def_subs_area now points to a buffer full of subscription info.
	   Each line of the stuff is of the form:
	   class,inst,recipient

	   Commas and newlines may not appear as part of the class,
	   instance, or recipient. XXX!
	   */

	/* split up the subscription info */
	for (cp = def_sub_area; cp < def_sub_area + statbuf.st_size; cp++) {
	    if (*cp == '\n' || *cp == ',')
		*cp = '\0';
	}
	default_notice.z_message = def_sub_area;
	default_notice.z_message_len = statbuf.st_size + 1;
	default_notice.z_auth = 1;
	defaults_read = 1;
    }

    /* needed later for access_check() */
    default_notice.z_sender = person;
    subs = extract_subscriptions(&default_notice);
    /* replace any non-* recipients with "person" */

    for (sub = subs; sub; sub = sub->next) {
	/* if not a wildcard, replace it with person */
	if (strcmp(sub->dest.recip->string, "*")) {
	    free_string(sub->dest.recip);
	    sub->dest.recip = make_string(person, 0);
	} else {		/* replace with null recipient */
	    free_string(sub->dest.recip);
	    sub->dest.recip = dup_string(empty);
	}
    }
    return subs;
}

/*
 * Cancel a specific set of subscriptions.
 */

Code_t
subscr_cancel(struct sockaddr_in *sin,
	      ZNotice_t *notice)
{
    ZRealm *realm;
    Client *who;
    Destlist *cancel_subs, *subs, *cancel_next, *client_subs, *client_next;
    Code_t retval;
    int found = 0;

    who = client_find(&sin->sin_addr, notice->z_port);
    if (!who)
	return ZSRV_NOCLT;

    if (!who->subs)
	return ZSRV_NOSUB;

    cancel_subs = extract_subscriptions(notice);
    if (!cancel_subs)
	return ZERR_NONE;	/* no subscr -> no error */

    for (subs = cancel_subs; subs; subs = cancel_next) {
	cancel_next = subs->next;
	for (client_subs = who->subs; client_subs; client_subs = client_next) {
	    client_next = client_subs->next;
	    if (ZDest_eq(&client_subs->dest, &subs->dest)) {
		Destlist_delete(client_subs);
		retval = triplet_deregister(who, &client_subs->dest, NULL);
		if (retval == ZSRV_EMPTYCLASS &&
		    client_subs->dest.recip->string[0] == '@') {
		    realm =
			realm_get_realm_by_name(client_subs->dest.recip->string
						+ 1);
		    if (realm)
			subscr_unsub_sendit(who, client_subs, realm);
		    realm = NULL;
		}
		free_subscription(client_subs);
		found = 1;
		break;
	    }
	}
    }

    free_subscriptions(cancel_subs);

    if (found) {
	return ZERR_NONE;
    } else {
	return ZSRV_NOSUB;
    }
}

Code_t
subscr_realm_cancel(struct sockaddr_in *sin,
		    ZNotice_t *notice,
		    ZRealm *realm)
{
    Destlist *cancel_subs, *subs, *client_subs, *next, *next2;
    int found = 0;

    if (!realm)
        return ZSRV_NORLM;

    if (!realm->subs)
        return ZSRV_NOSUB;

    cancel_subs = extract_subscriptions(notice);
    if (!cancel_subs)
        return ZERR_NONE;       /* no subscr -> no error */

    for (subs = cancel_subs; subs; subs = next) {
        next = subs->next;
        for (client_subs = realm->subs; client_subs; client_subs = next2) {
            next2 = client_subs->next;
            if (ZDest_eq(&client_subs->dest, &subs->dest)) {
                Destlist_delete(client_subs);
                triplet_deregister(realm->client, &client_subs->dest, realm);
		free_subscription(client_subs);
                found = 1;
                break;
            }
        }
    }

    free_subscriptions(cancel_subs);

    if (found) {
        return ZERR_NONE;
    } else {
        return ZSRV_NOSUB;
    }
}

/*
 * Cancel all the subscriptions for this client.
 */

void
subscr_cancel_client(Client *client)
{
    Destlist *subs, *next;
    Code_t retval;
    ZRealm *realm;

    if (!client->subs)
	return;

    for (subs = client->subs; subs; subs = next) {
	next = subs->next;
	retval = triplet_deregister(client, &subs->dest, NULL);
	if (retval == ZSRV_EMPTYCLASS &&
	    subs->dest.recip->string[0] == '@') {
	    realm = realm_get_realm_by_name(subs->dest.recip->string + 1);
	    if (realm)
		subscr_unsub_sendit(client, subs, realm);
	    realm = NULL;
	}
	free_subscription(subs);
    }

    client->subs = NULL;
}

/*
 * Send the requester a list of his current subscriptions
 */

void
subscr_sendlist(ZNotice_t *notice,
		int auth,
		struct sockaddr_in *who)
{
    char **answer;
    int found;
    struct sockaddr_in send_to_who;
    Code_t retval;

    answer = subscr_marshal_subs(notice, auth, who, &found);
    send_to_who = *who;
    send_to_who.sin_port = notice->z_port;  /* Return port */

    retval = ZSetDestAddr(&send_to_who);
    if (retval != ZERR_NONE) {
	syslog(LOG_WARNING, "subscr_sendlist set addr: %s",
	       error_message(retval));
	if (answer)
	    free(answer);
	return;
    }

    /* XXX for now, don't do authentication */
    auth = 0;

    notice->z_kind = ACKED;

    /* use xmit_frag() to send each piece of the notice */

    retval = ZSrvSendRawList(notice, answer, found * NUM_FIELDS, xmit_frag);
    if (retval != ZERR_NONE)
	syslog(LOG_WARNING, "subscr_sendlist xmit: %s", error_message(retval));
    if (answer)
	free(answer);
}

static char **
subscr_marshal_subs(ZNotice_t *notice,
		    int auth,
		    struct sockaddr_in *who,
		    int *found)
{
    char **answer = NULL;
    unsigned short temp;
    Code_t retval;
    Client *client = NULL;
    Destlist *subs = NULL, *sub;
    int i;
    int defsubs = 0;

    *found = 0;

    /* Note that the following code is an incredible crock! */

    /* We cannot send multiple packets as acknowledgements to the client,
       since the hostmanager will ignore the later packets.  So we need
       to send directly to the client. */

    /* Make our own copy so we can send directly back to the client */
    /* RSF 11/07/87 */

    if (strcmp(notice->z_opcode, CLIENT_GIMMESUBS) == 0) {
	/* If the client has requested his current subscriptions,
	   the message field of the notice contains the port number
	   of the client for which the sender desires the subscription
	   list.  The port field is the port of the sender. */

	retval = ZReadAscii16(notice->z_message, notice->z_message_len, &temp);
	if (retval != ZERR_NONE) {
	    syslog(LOG_WARNING, "subscr_marshal read port num: %s",
		   error_message(retval));
	    return(NULL);
	}

	client = client_find(&who->sin_addr, htons(temp));

	if (client)
	    subs = client->subs;
    } else if (strcmp(notice->z_opcode, CLIENT_GIMMEDEFS) == 0) {
	/* subscr_copy_def_subs allocates new pointer rings, so
	   it must be freed when finished.
	   the string areas pointed to are static, however.*/
	subs = subscr_copy_def_subs(notice->z_sender);
	defsubs = 1;
    } else {
	syslog(LOG_ERR, "subscr_marshal bogus opcode %s",
	       notice->z_opcode);
	return(NULL);
    }

    if (subs) {

	/* check authenticity here.  The user must be authentic to get
	   a list of subscriptions. If he is not subscribed to
	   anything, this if-clause fails, and he gets a response
	   indicating no subscriptions.
	   if retrieving default subscriptions, don't care about
	   authentication. */

	if (!auth && !defsubs)
	    return(NULL);
	if (!defsubs) {
	    if (client && (strcmp(client->principal->string,
				  notice->z_sender) != 0)) {
		zdbug ((LOG_DEBUG,
			"subscr_marshal: %s requests subs for %s at %s/%d",
			notice->z_sender, client->principal->string,
			inet_ntoa(who->sin_addr), ntohs(who->sin_port)));
		return 0;
	    }
	}

	for (sub = subs; sub; sub = sub->next)
	    (*found)++;

	/* found is now the number of subscriptions */

	/* coalesce the subscription information into a list of char *'s */
	answer = (char **) malloc((*found) * NUM_FIELDS * sizeof(char *));
	if (answer == NULL) {
	    syslog(LOG_ERR, "subscr no mem(answer)");
	    *found = 0;
	} else {
	    i = 0;
	    for (sub = subs; sub; sub = sub->next) {
		answer[i * NUM_FIELDS] = sub->dest.classname->string;
		answer[i * NUM_FIELDS + 1] = sub->dest.inst->string;
		answer[i * NUM_FIELDS + 2] = sub->dest.recip->string;
		i++;
	    }
	}
    }
    if (defsubs)
	free_subscriptions(subs);
    return answer;
}

static Code_t
subscr_send_some_subs(char *opcode, struct sockaddr_in *addr, Destlist *subs, char *subject)
{
    char *list[NUM_FIELDS];
    Code_t retval;

    for (; subs; subs = subs->next) {
	/* for each subscription */
	list[0] = subs->dest.classname->string;
	list[1] = subs->dest.inst->string;
	list[2] = subs->dest.recip->string;
	retval = bdump_send_list_tcp(ACKED, addr,
				     ZEPHYR_CTL_CLASS, "",
				     opcode, "", "", list,
				     NUM_FIELDS);
	if (retval == ZERR_PKTLEN) {
	    syslog(LOG_ERR, "subscr_send_some_subs: dropping overlarge packet (%s)", subject);
	} else if (retval != ZERR_NONE) {
		syslog(LOG_ERR, "subscr_send_some_subs: bdump_send_list_tcp: %s",
		       error_message(retval));
		return retval;
	}
    }

    return ZERR_NONE;
}

/*
 * Send the client's subscriptions to another server
 */

/* version is currently unused; if necessary later versions may key off it
   to determine what to send to the peer (protocol changes) */

/*ARGSUSED*/
Code_t
subscr_send_subs(Client *client)
{
#ifdef HAVE_KRB5
    char buf[512];
    unsigned char *bufp;
#else
#ifdef HAVE_KRB4
    char buf[512];
    C_Block cblock;
#endif /* HAVE_KRB4 */
#endif
    char buf2[512];
    char *list[7 * NUM_FIELDS];
    int num = 0;
    Code_t retval;

    sprintf(buf2, "%d",ntohs(client->addr.sin_port));

    list[num++] = buf2;

#ifdef HAVE_KRB5
#ifdef HAVE_KRB4 /* XXX make this optional for server transition time */
    if (Z_enctype(client->session_keyblock) == ENCTYPE_DES_CBC_CRC) {
	bufp = malloc(Z_keylen(client->session_keyblock));
	if (bufp == NULL) {
	    syslog(LOG_WARNING, "subscr_send_subs: cannot allocate memory for DES keyblock: %m");
	    return errno;
	}
	des_ecb_encrypt((C_Block *)Z_keydata(client->session_keyblock), (C_Block *)bufp, serv_ksched.s, DES_ENCRYPT);
	retval = ZMakeAscii(buf, sizeof(buf), bufp, Z_keylen(client->session_keyblock));
    } else {
#endif
	bufp = malloc(Z_keylen(client->session_keyblock) + 8); /* + enctype
								+ length */
	if (bufp == NULL) {
	    syslog(LOG_WARNING, "subscr_send_subs: cannot allocate memory for keyblock: %m");
	    return errno;
	}
	*(krb5_enctype *)&bufp[0] = htonl(Z_enctype(client->session_keyblock));
	*(uint32_t *)&bufp[4] = htonl(Z_keylen(client->session_keyblock));
	memcpy(&bufp[8], Z_keydata(client->session_keyblock), Z_keylen(client->session_keyblock));

	retval = ZMakeZcode(buf, sizeof(buf), bufp, Z_keylen(client->session_keyblock) + 8);
#ifdef HAVE_KRB4
    }
#endif /* HAVE_KRB4 */
#else /* HAVE_KRB5 */
#ifdef HAVE_KRB4
    des_ecb_encrypt((des_cblock *)client->session_key, (des_cblock *)cblock,
		    serv_ksched.s, DES_ENCRYPT);

    retval = ZMakeAscii(buf, sizeof(buf), cblock, sizeof(C_Block));
#endif /* HAVE_KRB4 */
#endif /* HAVE_KRB5 */

#if defined(HAVE_KRB4) || defined(HAVE_KRB5)
    if (retval != ZERR_NONE) {
    } else {
	list[num++] = buf;
    }
#endif /* HAVE_KRB4 || HAVE_KRB5*/
    retval = bdump_send_list_tcp(SERVACK, &client->addr, ZEPHYR_ADMIN_CLASS,
				 num > 1 ? "CBLOCK" : "", ADMIN_NEWCLT,
				 client->principal->string, "", list, num);
    if (retval != ZERR_NONE) {
	syslog(LOG_ERR, "subscr_send_subs newclt: %s", error_message(retval));
	return retval;
    }

    retval = subscr_send_some_subs(CLIENT_SUBSCRIBE, &client->addr, client->subs, client->principal->string);
    if (retval != ZERR_NONE)
	syslog(LOG_ERR, "subscr_send_subs: subscr_send_some_subs: %s", error_message(retval));
    return retval;
}

/*
 * free the memory allocated for the list of subscriptions.
 */

/*
 * free the memory allocated for one subscription.
 */

static void
free_subscription(Destlist *sub)
{
    free_string(sub->dest.classname);
    free_string(sub->dest.inst);
    free_string(sub->dest.recip);
    free(sub);
}

static void
free_subscriptions(Destlist *subs)
{
    Destlist *next;

    for (; subs; subs = next) {
	next = subs->next;
	free_subscription (subs);
    }
}

#define	ADVANCE(xx)	{ cp += (strlen(cp) + 1); \
		  if (cp >= notice->z_message + notice->z_message_len) { \
			  syslog(LOG_WARNING, "malformed subscription %d", \
				 xx); \
			  return subs; \
		  }}

/*
 * Parse the message body, returning a linked list of subscriptions, or
 * NULL if there are no subscriptions there.
 */

static Destlist *
extract_subscriptions(ZNotice_t *notice)
{
    Destlist *subs = NULL, *sub;
    char *recip, *class_name, *classinst;
    char *cp = notice->z_message;

    /* parse the data area for the subscriptions */
    while (cp < notice->z_message + notice->z_message_len) {
	class_name = cp;
	if (*cp == '\0')	    /* we've exhausted the subscriptions */
	    return(subs);
	ADVANCE(1);
	classinst = cp;
	ADVANCE(2);
	recip = cp;
	cp += (strlen(cp) + 1);
	if (cp > notice->z_message + notice->z_message_len) {
	    syslog(LOG_WARNING, "malformed sub 3");
	    return subs;
	}
	sub = (Destlist *) malloc(sizeof(Destlist));
	if (!sub) {
	    syslog(LOG_WARNING, "ex_subs: no mem 2");
	    return subs;
	}
	sub->dest.classname = make_string(class_name, 1);
	sub->dest.inst = make_string(classinst, 1);
	/* Nuke @REALM if REALM is us. */
	if (recip[0] == '@' && !strcmp(recip + 1, ZGetRealm()))
	    sub->dest.recip = make_string("", 0);
	else
	    sub->dest.recip = make_string(recip, 0);
	Destlist_insert(&subs, sub);
    }
    return subs;
}

/*
 * print subscriptions in subs onto fp.
 * assumed to be called with SIGFPE blocked
 * (true if called from signal handler)
 */

void
subscr_dump_subs(FILE *fp,
		 Destlist *subs)
{
    if (!subs)			/* no subscriptions to dump */
	return;

    for (; subs; subs = subs->next) {
	fputs("\t'", fp);
	dump_quote(subs->dest.classname->string, fp);
	fputs("' '", fp);
	dump_quote(subs->dest.inst->string, fp);
	fputs("' '", fp);
	dump_quote(subs->dest.recip->string, fp);
	fputs("'\n", fp);
    }
}

#define I_ADVANCE(xx)   { cp += (strlen(cp) + 1); \
                  if (cp >= notice->z_message + notice->z_message_len) { \
                          syslog(LOG_WARNING, "malformed subscription %d", \
                                 xx); \
                          return (ZERR_NONE); \
                  }}

/* As it exists, this function expects to take only the first sub from the
 * Destlist. At some point, it and the calling code should be replaced */
static Code_t
subscr_realm_sendit(Client *who,
		    Destlist *subs,
		    ZNotice_t *notice,
		    ZRealm *realm)
{
  ZNotice_t snotice;
  char *pack;
  int packlen;
  char **text;
  Code_t retval;
  char addr[16];          /* xxx.xxx.xxx.xxx max */
  char port[16];

  if ((text=(char **)malloc((NUM_FIELDS + 2)*sizeof(char *))) == (char **)0) {
      syslog(LOG_ERR, "subscr_rlm_sendit malloc");
      return(ENOMEM);
  }
  /* convert the address to a string of the form x.x.x.x/port */
  strcpy(addr, inet_ntoa(who->addr.sin_addr));
  if ((retval = ZMakeAscii(port, sizeof(port), (unsigned char *)
                           &who->addr.sin_port, sizeof(unsigned short))) != ZERR_NONE)
    {
      syslog(LOG_ERR, "subscr_rlm_sendit make ascii: %s",
             error_message(retval));
      return(ZERR_NONE);
    }
  text[0] = addr;
  text[1] = port;

  text[2] = subs->dest.classname->string;
  text[3] = subs->dest.inst->string;
  text[4] = subs->dest.recip->string;

  zdbug((LOG_DEBUG, "subscr_realm_sendit %s/%s (%s) %s,%s,%s\n",
         text[0], text[1], who->principal->string, text[2], text[3], text[4]));

  /* format snotice */
  memset (&snotice, 0, sizeof(snotice));
  snotice.z_class_inst = ZEPHYR_CTL_REALM;
  snotice.z_opcode = REALM_REQ_SUBSCRIBE;
  snotice.z_port = srv_addr.sin_port;

  snotice.z_class = ZEPHYR_CTL_CLASS;

  snotice.z_recipient = "";
  snotice.z_kind = ACKED;
  snotice.z_num_other_fields = 0;
  snotice.z_sender = who->principal->string;
  snotice.z_recipient = notice->z_recipient;
  snotice.z_default_format = notice->z_default_format;

  if ((retval = ZFormatNoticeList(&snotice, text, NUM_FIELDS + 2,
                                  &pack, &packlen, ZNOAUTH)) != ZERR_NONE)
    {
      syslog(LOG_WARNING, "subscr_rlm_sendit format: %s",
             error_message(retval));
      free(text);
      return(ZERR_NONE);
    }
  free(text);

  if ((retval = ZParseNotice(pack, packlen, &snotice)) != ZERR_NONE) {
    syslog(LOG_WARNING, "subscr_rlm_sendit parse: %s",
           error_message(retval));
    free(pack);
    return(ZERR_NONE);
  }

  realm_handoff(&snotice, 1, &(who->addr), realm, 0);
  free(pack);

  return(ZERR_NONE);
}

/* Called from subscr_realm and subscr_foreign_user */
static Code_t
subscr_add_raw(Client *client,
	       ZRealm *realm,
	       Destlist *newsubs)
{
  Destlist *subs, *subs2, **head;
  Code_t retval;

  head = (realm) ? &realm->subs : &client->subs;

  /* Loop over the new subscriptions. */
  for (subs = newsubs; subs; subs = subs2) {
    subs2 = subs->next;
#ifdef DEBUG
    zdbug((LOG_DEBUG,"subscr_add_raw: %s/%s/%s", subs->dest.classname->string, subs->dest.inst->string, subs->dest.recip->string));
    if (realm)
      zdbug((LOG_DEBUG,"subscr_add_raw: realm is %s", realm->name));
#endif
    retval = triplet_register(client, &subs->dest, realm);
    if (retval != ZERR_NONE) {
	free_subscription(subs);
	if (retval == ZSRV_CLASSXISTS) {
	    continue;
	} else {
	    free_subscriptions(subs2);
	    return retval;
	}
    } else {
      if (!realm) {
	ZRealm *remrealm =
	  realm_get_realm_by_name(subs->dest.recip->string + 1);
	if (remrealm) {
	  Destlist *sub = (Destlist *) malloc(sizeof(Destlist));
	  if (!sub) {
            syslog(LOG_WARNING, "subscr_add_raw: no mem");
	  } else {
	    sub->dest.classname = make_string(subs->dest.classname->string, 0);
	    sub->dest.inst = make_string(subs->dest.inst->string, 0);
	    sub->dest.recip = make_string(subs->dest.recip->string, 0);
	    zdbug ((LOG_DEBUG, "subscr: add %s/%s/%s in %s",
		    sub->dest.classname->string, sub->dest.inst->string,
		    sub->dest.recip->string, remrealm->name));
	    Destlist_insert(&remrealm->remsubs, sub);
	  }
	}
      }
    }
    Destlist_insert(head, subs);
  }
  return ZERR_NONE;
}

/* Called from bdump_recv_loop to decapsulate realm subs */
Code_t
subscr_realm(ZRealm *realm,
	     ZNotice_t *notice)
{
        Destlist  *newsubs;

        newsubs = extract_subscriptions(notice);

        if (!newsubs) {
                syslog(LOG_WARNING, "empty subs in subscr_realm");
                return(ZERR_NONE);
        }

        return(subscr_add_raw(realm->client, realm, newsubs));
}

/* Like realm_sendit, this only takes one item from subs */
static void
subscr_unsub_sendit(Client *who,
		    Destlist *subs,
		    ZRealm *realm)
{
  ZNotice_t unotice;
  Code_t retval;
  char **list;
  char *pack;
  int packlen;
  Destlist *subsp, *subsn;

  for (subsp = realm->remsubs; subsp; subsp = subsn) {
    subsn = subsp->next;
    if (ZDest_eq(&subs->dest, &subsp->dest)) {
      zdbug ((LOG_DEBUG, "subscr: del %s/%s/%s in %s",
	      subsp->dest.classname->string, subsp->dest.inst->string,
	      subsp->dest.recip->string, realm->name));
      Destlist_delete(subsp);
      free_subscription(subsp);
      break;
    }
  }

  if ((list=(char **)malloc((NUM_FIELDS)*sizeof(char *))) == (char **)0) {
      syslog(LOG_ERR, "subscr_unsub_sendit malloc");
      return;
  }

  list[0] = subs->dest.classname->string;
  list[1] = subs->dest.inst->string;
  list[2] = "";

  memset(&unotice, 0, sizeof(unotice));
  unotice.z_class = ZEPHYR_CTL_CLASS;
  unotice.z_class_inst = ZEPHYR_CTL_REALM;
  unotice.z_opcode = REALM_UNSUBSCRIBE;
  unotice.z_recipient = "";
  unotice.z_kind = ACKED;

  unotice.z_sender = "";
  unotice.z_port = srv_addr.sin_port;
  unotice.z_num_other_fields = 0;
  unotice.z_default_format = "";

  if ((retval = ZFormatNoticeList(&unotice, list, NUM_FIELDS, &pack, &packlen, ZNOAUTH)) != ZERR_NONE) {
    syslog(LOG_WARNING, "subscr_unsub_sendit format: %s",
           error_message(retval));
    free(list);
    return;
  }
  free(list);

  if ((retval = ZParseNotice(pack, packlen, &unotice)) != ZERR_NONE) {
    syslog(LOG_WARNING, "subscr_unsub_sendit parse: %s",
           error_message(retval));
    free(pack);
    return;
  }
  realm_handoff(&unotice, 1, who ? &(who->addr) : NULL, realm, 0);
  free(pack);
}

/* Called from bump_send_loop by way of realm_send_realms */
Code_t
subscr_send_realm_subs(ZRealm *realm)
{
  char buf[512];
  char *list[7 * NUM_FIELDS];
  int num = 0;
  Code_t retval;

  strcpy(buf, realm->name);
  list[num++] = buf;

  retval = bdump_send_list_tcp(SERVACK, &srv_addr, ZEPHYR_ADMIN_CLASS,
                               "", ADMIN_NEWREALM, "", "", list, num);
  if (retval != ZERR_NONE) {
    syslog(LOG_ERR, "subscr_send_realm_subs newclt: %s", error_message(retval));
    return retval;
  }

  retval = subscr_send_some_subs(REALM_SUBSCRIBE, &srv_addr, realm->subs, realm->name);
  if (retval != ZERR_NONE)
      syslog(LOG_ERR, "subscr_send_realm_subs: subscr_send_some_subs: %s", error_message(retval));
  return retval;
}

Code_t
subscr_realm_subs(ZRealm *realm)
{
  Destlist *subs, *next;
  char *text[2 + NUM_FIELDS];
  unsigned short num = 0;
  Code_t retval;
  ZNotice_t snotice;
  char *pack;
  int packlen;
  Client **clientp;
  char port[16];

  if (!realm->remsubs)
    return ZERR_NONE;

  for (subs=realm->remsubs; subs; subs = next) {
    next = subs->next;
#ifdef DEBUG
    zdbug ((LOG_DEBUG, "realm_subs: %s/%s/%s", subs->dest.classname->string,
            subs->dest.inst->string, subs->dest.recip->string));
#endif

    num = 0;
    if ((retval = ZMakeAscii(port, sizeof(port), (unsigned char *)
			     &num, sizeof(unsigned short))) != ZERR_NONE)
      {
	syslog(LOG_ERR, "subscr_rlm_sendit make ascii: %s",
	       error_message(retval));
	return(ZERR_NONE);
      }

    text[0] = "0.0.0.0";
    text[1] = port;
    text[2] = subs->dest.classname->string;
    text[3] = subs->dest.inst->string;
    text[4] = subs->dest.recip->string;

    /* format snotice */
    memset (&snotice, 0, sizeof(snotice));
    snotice.z_class_inst = ZEPHYR_CTL_REALM;
    snotice.z_opcode = REALM_REQ_SUBSCRIBE;
    snotice.z_port = 0;
    snotice.z_class = ZEPHYR_CTL_CLASS;

    snotice.z_recipient = "";
    snotice.z_kind = ACKED;
    snotice.z_num_other_fields = 0;
    snotice.z_default_format = "";
    /* Evil. In the event this is ACL'd, pick a user who is subscribed and
       resubmit them as the sender. */
    clientp = triplet_lookup(&subs->dest);
    if (!clientp)
      snotice.z_sender = "";
    else
      snotice.z_sender = (*clientp)->principal->string;

    if ((retval = ZFormatNoticeList(&snotice, text, NUM_FIELDS + 2,
				    &pack, &packlen, ZNOAUTH)) != ZERR_NONE)
      {
	syslog(LOG_WARNING, "subscr_rlm_subs format: %s",
	       error_message(retval));
	return(ZERR_NONE);
      }

    if ((retval = ZParseNotice(pack, packlen, &snotice)) != ZERR_NONE) {
      syslog(LOG_WARNING, "subscr_rlm_subs parse: %s",
	     error_message(retval));
      free(pack);
      return(ZERR_NONE);
    }
    realm_handoff(&snotice, 1, NULL, realm, 0);
    free(pack);
  }

  return ZERR_NONE;
}

/* Called from subscr_foreign_user for REALM_REQ_SUBSCRIBE */
static Code_t
subscr_check_foreign_subs(ZNotice_t *notice,
			  struct sockaddr_in *who,
			  Server *server,
			  ZRealm *realm,
			  Destlist *newsubs)
{
    Destlist *subs, *next;
    Acl *acl;
    char **text;
    int found = 0;
    ZNotice_t snotice;
    char *pack, *cp;
    int packlen;
    Code_t retval;
    String *sender;

    for (subs = newsubs; subs; subs = subs->next)
	found++;

    if (found == 0)
	return(ZERR_NONE);

    sender = make_string(notice->z_sender, 0);

    if ((text = (char **)malloc((found * NUM_FIELDS + 2) * sizeof(char *)))
	== (char **) 0) {
	syslog(LOG_ERR, "subscr_ck_forn_subs no mem(text)");
	free_string(sender);
	return(ENOMEM);
    }

    /* grab the client information from the incoming message */
    cp = notice->z_message;
    text[0] = cp;

    I_ADVANCE(2);
    text[1] = cp;

    I_ADVANCE(3);

    found = 0;
    for (subs = newsubs; subs; subs = next) {
	ZRealm *rlm;
	next=subs->next;
	if (subs->dest.recip->string[0] != '\0') {
	  rlm = realm_which_realm(who);
	  syslog(LOG_WARNING, "subscr bad recip %s by %s (%s)",
		 subs->dest.recip->string,
		 sender->string, rlm->name);
	  continue;
	}
	acl = class_get_acl(subs->dest.classname);
	if (acl) {
	    rlm = realm_which_realm(who);
	    if (rlm && server == me_server) {
		if (!realm_sender_in_realm(rlm->name, sender->string)) {
		    syslog(LOG_WARNING, "subscr auth not verifiable %s (%s) class %s",
			   sender->string, rlm->name,
			   subs->dest.classname->string);
		    free_subscriptions(newsubs);
		    free_string(sender);
		    free(text);
		    return ZSRV_CLASSRESTRICTED;
		}
	    }
	    if (!access_check(sender->string, who, acl, SUBSCRIBE)) {
		syslog(LOG_WARNING, "subscr unauth %s class %s",
		       sender->string, subs->dest.classname->string);
		continue; /* the for loop */
	    }
	    if (wildcard_instance == subs->dest.inst) {
		if (!access_check(sender->string, who, acl, INSTWILD)) {
		    syslog(LOG_WARNING,
			   "subscr unauth %s class %s wild inst",
			   sender->string, subs->dest.classname->string);
		    continue;
		}
	    }
	}

	/* okay to subscribe.  save for return trip */
	text[found*NUM_FIELDS + 2] = subs->dest.classname->string;
	text[found*NUM_FIELDS + 3] = subs->dest.inst->string;
	text[found*NUM_FIELDS + 4] = "";
	found++;

	retval = triplet_register(realm->client, &subs->dest, realm);
#ifdef DEBUG
	zdbug ((LOG_DEBUG, "ck_frn_subs: %s/%s/%s", subs->dest.classname->string,
		subs->dest.inst->string, subs->dest.recip->string));
#endif

	if (retval != ZERR_NONE) {
	    if (retval == ZSRV_CLASSXISTS) {
		continue;
	    } else {
		free_subscriptions(newsubs); /* subs->next XXX */
		free_string(sender);
		free(text);
		return retval;
	    }
	}
	Destlist_insert(&realm->subs, subs);
    }
    /* don't send confirmation if we're not the initial server contacted */
    if (!(server_which_server(who) || found == 0)) {
	snotice = *notice;
	snotice.z_opcode = REALM_ADD_SUBSCRIBE;
	snotice.z_class_inst = ZEPHYR_CTL_REALM;
	snotice.z_port = srv_addr.sin_port;
	if ((retval = ZFormatNoticeList(&snotice, text, found * NUM_FIELDS + 2, &pack, &packlen, ZNOAUTH)) != ZERR_NONE) {
	    syslog(LOG_WARNING, "subscr_ck_forn_subs format: %s",
		   error_message(retval));
	    free_string(sender);
	    free(text);
	    return(ZERR_NONE);
	}
	if ((retval = ZParseNotice(pack, packlen, &snotice)) != ZERR_NONE) {
	    syslog(LOG_WARNING, "subscr_ck_forn_subs parse: %s",
		   error_message(retval));
	    free_string(sender);
	    free(text);
	    free(pack);
	    return(ZERR_NONE);
	}
	realm_handoff(&snotice, 1, who, realm, 0);
	free(pack);
    }
    free_string(sender);
    free(text);
    return ZERR_NONE;
}

/* Called from realm_control_dispatch for REALM_REQ/ADD_SUBSCRIBE */
Code_t subscr_foreign_user(ZNotice_t *notice,
			   struct sockaddr_in *who,
			   Server *server,
			   ZRealm *realm)
{
  Destlist *newsubs, *temp;
  Code_t status;
  Client *client;
  ZNotice_t snotice;
  struct sockaddr_in newwho;
  char *cp, *tp0;
#ifdef DEBUG
  char *tp1;
#endif
  char rlm_recipient[REALM_SZ + 1];

  tp0 = cp = notice->z_message;

  newwho.sin_addr.s_addr = inet_addr(cp);
  if (newwho.sin_addr.s_addr == INADDR_NONE) {
    syslog(LOG_ERR, "malformed addr from %s", notice->z_sender);
    return(ZERR_NONE);
  }

  I_ADVANCE(0);
#ifdef DEBUG
  tp1 = cp;
#endif

  snotice = *notice;

  if ((status = ZReadAscii(cp, strlen(cp), (unsigned char *)&snotice.z_port,
			   sizeof(unsigned short)))
      != ZERR_NONE)
    {
      syslog(LOG_ERR, "subscr_foreign_user read ascii: %s",
             error_message(status));
      return(ZERR_NONE);
    }

  I_ADVANCE(1);

  snotice.z_message = cp;
  snotice.z_message_len = notice->z_message_len - (cp - notice->z_message);

  newsubs = extract_subscriptions(&snotice);
  if (!newsubs) {
    syslog(LOG_WARNING, "empty subscr for %s", notice->z_sender);
    return(ZERR_NONE);
  }

  if (!strcmp(snotice.z_opcode, REALM_ADD_SUBSCRIBE)) {
    /* this was approved by the other realm, add subscriptions */

    if (!strcmp(tp0, "0.0.0.0")) {
      /* skip bogus ADD reply from subscr_realm_subs */
      zdbug((LOG_DEBUG, "subscr_foreign_user ADD skipped"));
      return(ZERR_NONE);
    }

    zdbug((LOG_DEBUG, "subscr_foreign_user ADD %s/%s", tp0, tp1));
    client = client_find(&newwho.sin_addr, snotice.z_port);
    if (client == (Client *)0) {
      syslog(LOG_WARNING, "no client at %s/%d",
             inet_ntoa(newwho.sin_addr), ntohs(snotice.z_port));
      free_subscriptions(newsubs);
      return(ZERR_NONE);
    }

    /* translate the recipient to represent the foreign realm */
    sprintf(rlm_recipient, "@%s", realm->name);
    for (temp = newsubs; temp; temp = temp->next) {
        temp->dest.recip = make_string(rlm_recipient, 0);
    }

    status = subscr_add_raw(client, (ZRealm *)0, newsubs);
  } else if (!strcmp(snotice.z_opcode, REALM_REQ_SUBSCRIBE)) {
    zdbug((LOG_DEBUG, "subscr_foreign_user REQ %s/%s", tp0, tp1));
    status = subscr_check_foreign_subs(notice, who, server, realm, newsubs);
  } else {
    syslog(LOG_ERR, "bogus opcode %s in subscr_forn_user",
           snotice.z_opcode);
    status = ZERR_NONE;
  }
  return(status);
}