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client.c

/* This file is part of the Project Athena Zephyr Notification System.
 * It contains functions for the Client Manager subsystem of the Zephyr server.
 *
 *    Created by: John T. Kohl
 *
 *    $Id: client.c,v 1.34 1999/01/22 23:19:41 ghudson Exp $
 *
 *    Copyright (c) 1987,1988,1991 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"
#include <sys/socket.h>

#if !defined (lint) && !defined (SABER)
static const char rcsid_client_c[] =
"$Id: client.c,v 1.34 1999/01/22 23:19:41 ghudson Exp $";
#endif

/*
 * External functions:
 *
 * Code_t client_register(notice, who, client, server, wantdefaults)
 *    ZNotice_t *notice;
 *    struct sockaddr_in *who;
 *    Client **client; (RETURN)
 *    Server *server;
 *    int wantdefaults;
 *
 * Code_t client_deregister(client, host, flush)
 *    Client *client;
 *    Host *host;
 *    int flush;
 *
 * Client *client_find(who, unsigned int port)
 *    struct in_addr *host;
 *    unsigned int port;
 *
 * void client_dump_clients(fp, clist)
 *    FILE *fp;
 *    Client *clist;
 */

/*
 * a client: allocate space, find or insert the address in the
 *    server's list of hosts, initialize and insert the client into
 *    the host's list of clients.
 *
 * This routine assumes that the client has not been registered yet.
 * The caller should check by calling client_find.
 */

#define HASHSIZE 1024
static Client *client_bucket[HASHSIZE];

#define INET_HASH(host, port) ((htonl((host)->s_addr) + \
                        htons((unsigned short) (port))) % HASHSIZE)

Code_t
client_register(notice, host, client_p, wantdefaults)
    ZNotice_t *notice;
    struct in_addr *host;
    Client **client_p;
    int wantdefaults;
{
    Client *client;
    Code_t retval;

    /* chain the client's host onto this server's host list */

#if 1
    zdbug((LOG_DEBUG, "client_register: adding %s at %s/%d",
         notice->z_sender, inet_ntoa(*host), ntohs(notice->z_port)));
#endif

    if (!notice->z_port)
      return ZSRV_BADSUBPORT;

    *client_p = client = client_find(host, notice->z_port);
    if (!client) {
      *client_p = client = (Client *) malloc(sizeof(Client));
      if (!client)
          return ENOMEM;
      memset(&client->addr, 0, sizeof(struct sockaddr_in));
#ifdef KERBEROS
      memset(&client->session_key, 0, sizeof(client->session_key));
#endif
      client->last_send = 0;
      client->last_ack = NOW;
      client->addr.sin_family = AF_INET;
      client->addr.sin_addr.s_addr = host->s_addr;
      client->addr.sin_port = notice->z_port;
      client->subs = NULL;
      client->realm = NULL;
      client->principal = make_string(notice->z_sender, 0);
      LIST_INSERT(&client_bucket[INET_HASH(&client->addr.sin_addr,
                                   notice->z_port)], client);
    }

    /* Add default subscriptions only if this is not resulting from a brain
     * dump, AND this request wants defaults. */
    if (!bdumping && wantdefaults)
      return subscr_def_subs(client);
    else
      return ZERR_NONE;
}

/*
 * Deregister the client, freeing resources.  
 * Remove any packets in the nack queue, release subscriptions, release
 * locations, and dequeue him from the host.
 */

void
client_deregister(client, flush)
    Client *client;
    int flush;
{
    LIST_DELETE(client);
    nack_release(client);
    subscr_cancel_client(client);
    free_string(client->principal);
    if (flush)
      uloc_flush_client(&client->addr);
    free(client);
}

void
client_flush_host(host)
    struct in_addr *host;
{
    int i;
    Client *client, *next;

    for (i = 0; i < HASHSIZE; i++) {
      for (client = client_bucket[i]; client; client = next) {
          next = client->next;
          if (client->addr.sin_addr.s_addr == host->s_addr)
            client_deregister(client, 1);
      }
    }
    uloc_hflush(host);
}

Code_t
client_send_clients()
{
    int i;
    Client *client;
    Code_t retval;

    for (i = 0; i < HASHSIZE; i++) {
      /* Allow packets to be processed between rows of the hash table. */
      if (packets_waiting()) {
          bdumping = 0;
          bdump_concurrent = 1;
          handle_packet();
          bdump_concurrent = 0;
          bdumping = 1;
      }
      for (client = client_bucket[i]; client; client = client->next) {
          if (client->subs) {
            retval = subscr_send_subs(client);
            if (retval != ZERR_NONE)
                return retval;
          }
      }
    }
    return ZERR_NONE;
}

/*
 * dump info about clients in this clist onto the fp.
 * assumed to be called with SIGFPE blocked
 * (true if called from signal handler)
 */

void
client_dump_clients(fp)
    FILE *fp;
{
    Client *client;
    int i;

    for (i = 0; i < HASHSIZE; i++) {
      for (client = client_bucket[i]; client; client = client->next) {
          fprintf(fp, "%s/%d (%s):\n", inet_ntoa(client->addr.sin_addr),
                ntohs(client->addr.sin_port), client->principal->string);
          subscr_dump_subs(fp, client->subs);
      }
    }
}

/*
 * find a client by host and port
 */

Client *
client_find(host, port)
    struct in_addr *host;
    unsigned int port;
{
    Client *client;
    long hashval;

    hashval = INET_HASH(host, port);
    for (client = client_bucket[hashval]; client; client = client->next) {
      if (client->addr.sin_addr.s_addr == host->s_addr
          && client->addr.sin_port == port)
          return client;
    }
    return NULL;
}


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