/*
 * Copyright (c) 1993 by the University of Southern California
 * All rights reserved.
 *
 * Permission to use, copy, modify, and distribute this software and its
 * documentation in source and binary forms for non-commercial purposes
 * and without fee is hereby granted, provided that the above copyright
 * notice appear in all copies and that both the copyright notice and
 * this permission notice appear in supporting documentation. and that
 * any documentation, advertising materials, and other materials related
 * to such distribution and use acknowledge that the software was
 * developed by the University of Southern California, Information
 * Sciences Institute.  The name of the University may not be used to
 * endorse or promote products derived from this software without
 * specific prior written permission.
 *
 * THE UNIVERSITY OF SOUTHERN CALIFORNIA makes no representations about
 * the suitability of this software for any purpose.  THIS SOFTWARE IS
 * PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES,
 * INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 *
 * Other copyrights might apply to parts of this software and are so
 * noted when applicable.
 *
 * $FreeBSD: src/usr.sbin/mrouted/rsrr.c,v 1.8.2.1 2001/05/12 09:48:20 kris Exp $
 * $DragonFly: src/usr.sbin/mrouted/rsrr.c,v 1.4 2004/03/15 18:10:28 dillon Exp $
 */

/* RSRR code written by Daniel Zappala, USC Information Sciences Institute,
 * April 1995.
 */

/* May 1995 -- Added support for Route Change Notification */

#ifdef RSRR

#include "defs.h"
#include <sys/param.h>
#ifdef HAVE_SA_LEN
#include <stddef.h>	/* for offsetof */
#endif

/*
 * Exported variables.
 */
int rsrr_socket;			/* interface to reservation protocol */

/* 
 * Global RSRR variables.
 */
char rsrr_recv_buf[RSRR_MAX_LEN];	/* RSRR receive buffer */
char rsrr_send_buf[RSRR_MAX_LEN];	/* RSRR send buffer */

struct sockaddr_un client_addr;
int client_length = sizeof(client_addr);


/*
 * Procedure definitions needed internally.
 */
static void	rsrr_accept(int recvlen);
static void	rsrr_accept_iq(void);
static int	rsrr_accept_rq(struct rsrr_rq *route_query, int flags,
					struct gtable *gt_notify);
static void	rsrr_read(int, fd_set *);
static int	rsrr_send(int sendlen);
static void	rsrr_cache(struct gtable *gt,
					struct rsrr_rq *route_query);

/* Initialize RSRR socket */
void
rsrr_init(void)
{
    int servlen;
    struct sockaddr_un serv_addr;

    if ((rsrr_socket = socket(AF_UNIX, SOCK_DGRAM, 0)) < 0)
	log(LOG_ERR, errno, "Can't create RSRR socket");

    unlink(RSRR_SERV_PATH);
    bzero((char *) &serv_addr, sizeof(serv_addr));
    serv_addr.sun_family = AF_UNIX;
    strcpy(serv_addr.sun_path, RSRR_SERV_PATH);
#ifdef HAVE_SA_LEN
    servlen = offsetof(struct sockaddr_un, sun_path) +
		strlen(serv_addr.sun_path);
    serv_addr.sun_len = servlen;
#else
    servlen = sizeof(serv_addr.sun_family) + strlen(serv_addr.sun_path);
#endif
 
    if (bind(rsrr_socket, (struct sockaddr *) &serv_addr, servlen) < 0)
	log(LOG_ERR, errno, "Can't bind RSRR socket");

    if (register_input_handler(rsrr_socket, rsrr_read) < 0)
	log(LOG_WARNING, 0, "Couldn't register RSRR as an input handler");
}

/* Read a message from the RSRR socket */
static void
rsrr_read(int f, fd_set *rfd)
{
    int rsrr_recvlen;
    
    bzero((char *) &client_addr, sizeof(client_addr));
    rsrr_recvlen = recvfrom(rsrr_socket, rsrr_recv_buf, sizeof(rsrr_recv_buf),
			    0, (struct sockaddr *)&client_addr, &client_length);
    if (rsrr_recvlen < 0) {	
	if (errno != EINTR)
	    log(LOG_ERR, errno, "RSRR recvfrom");
	return;
    }
    rsrr_accept(rsrr_recvlen);
}

/* Accept a message from the reservation protocol and take
 * appropriate action.
 */
static void
rsrr_accept(int recvlen)
{
    struct rsrr_header *rsrr;
    struct rsrr_rq *route_query;
    
    if (recvlen < RSRR_HEADER_LEN) {
	log(LOG_WARNING, 0,
	    "Received RSRR packet of %d bytes, which is less than min size",
	    recvlen);
	return;
    }
    
    rsrr = (struct rsrr_header *) rsrr_recv_buf;
    
    if (rsrr->version > RSRR_MAX_VERSION) {
	log(LOG_WARNING, 0,
	    "Received RSRR packet version %d, which I don't understand",
	    rsrr->version);
	return;
    }
    
    switch (rsrr->version) {
      case 1:
	switch (rsrr->type) {
	  case RSRR_INITIAL_QUERY:
	    /* Send Initial Reply to client */
	    IF_DEBUG(DEBUG_RSRR)
	    log(LOG_DEBUG, 0, "Received Initial Query\n");
	    rsrr_accept_iq();
	    break;
	  case RSRR_ROUTE_QUERY:
	    /* Check size */
	    if (recvlen < RSRR_RQ_LEN) {
		log(LOG_WARNING, 0,
		    "Received Route Query of %d bytes, which is too small",
		    recvlen);
		break;
	    }
	    /* Get the query */
	    route_query = (struct rsrr_rq *) (rsrr_recv_buf + RSRR_HEADER_LEN);
	    IF_DEBUG(DEBUG_RSRR)
	    log(LOG_DEBUG, 0,
		"Received Route Query for src %s grp %s notification %d",
		inet_fmt(route_query->source_addr.s_addr, s1),
		inet_fmt(route_query->dest_addr.s_addr,s2),
		BIT_TST(rsrr->flags,RSRR_NOTIFICATION_BIT));
	    /* Send Route Reply to client */
	    rsrr_accept_rq(route_query,rsrr->flags,NULL);
	    break;
	  default:
	    log(LOG_WARNING, 0,
		"Received RSRR packet type %d, which I don't handle",
		rsrr->type);
	    break;
	}
	break;
	
      default:
	log(LOG_WARNING, 0,
	    "Received RSRR packet version %d, which I don't understand",
	    rsrr->version);
	break;
    }
}

/* Send an Initial Reply to the reservation protocol. */
static void
rsrr_accept_iq(void)
{
    struct rsrr_header *rsrr;
    struct rsrr_vif *vif_list;
    struct uvif *v;
    int vifi, sendlen;
    
    /* Check for space.  There should be room for plenty of vifs,
     * but we should check anyway.
     */
    if (numvifs > RSRR_MAX_VIFS) {
	log(LOG_WARNING, 0,
	    "Can't send RSRR Route Reply because %d is too many vifs",
	    numvifs);
	return;
    }
    
    /* Set up message */
    rsrr = (struct rsrr_header *) rsrr_send_buf;
    rsrr->version = 1;
    rsrr->type = RSRR_INITIAL_REPLY;
    rsrr->flags = 0;
    rsrr->num = numvifs;
    
    vif_list = (struct rsrr_vif *) (rsrr_send_buf + RSRR_HEADER_LEN);
    
    /* Include the vif list. */
    for (vifi=0, v = uvifs; vifi < numvifs; vifi++, v++) {
	vif_list[vifi].id = vifi;
	vif_list[vifi].status = 0;
	if (v->uv_flags & VIFF_DISABLED)
	    BIT_SET(vif_list[vifi].status,RSRR_DISABLED_BIT);
	vif_list[vifi].threshold = v->uv_threshold;
	vif_list[vifi].local_addr.s_addr = v->uv_lcl_addr;
    }
    
    /* Get the size. */
    sendlen = RSRR_HEADER_LEN + numvifs*RSRR_VIF_LEN;
    
    /* Send it. */
    IF_DEBUG(DEBUG_RSRR)
    log(LOG_DEBUG, 0, "Send RSRR Initial Reply");
    rsrr_send(sendlen);
}

/* Send a Route Reply to the reservation protocol.  The Route Query
 * contains the query to which we are responding.  The flags contain
 * the incoming flags from the query or, for route change
 * notification, the flags that should be set for the reply.  The
 * kernel table entry contains the routing info to use for a route
 * change notification.
 */
static int
rsrr_accept_rq(struct rsrr_rq *route_query, int flags, struct gtable *gt_notify)
{
    struct rsrr_header *rsrr;
    struct rsrr_rr *route_reply;
    struct gtable *gt,local_g;
    struct rtentry *r;
    int sendlen;
    u_long mcastgrp;
    
    /* Set up message */
    rsrr = (struct rsrr_header *) rsrr_send_buf;
    rsrr->version = 1;
    rsrr->type = RSRR_ROUTE_REPLY;
    rsrr->flags = 0;
    rsrr->num = 0;
    
    route_reply = (struct rsrr_rr *) (rsrr_send_buf + RSRR_HEADER_LEN);
    route_reply->dest_addr.s_addr = route_query->dest_addr.s_addr;
    route_reply->source_addr.s_addr = route_query->source_addr.s_addr;
    route_reply->query_id = route_query->query_id;
    
    /* Blank routing entry for error. */
    route_reply->in_vif = 0;
    route_reply->reserved = 0;
    route_reply->out_vif_bm = 0;
    
    /* Get the size. */
    sendlen = RSRR_RR_LEN;

    /* If kernel table entry is defined, then we are sending a Route Reply
     * due to a Route Change Notification event.  Use the kernel table entry
     * to supply the routing info.
     */
    if (gt_notify) {
	/* Set flags */
	rsrr->flags = flags;
	/* Include the routing entry. */
	route_reply->in_vif = gt_notify->gt_route->rt_parent;
	if (BIT_TST(flags,RSRR_NOTIFICATION_BIT))
	    route_reply->out_vif_bm = gt_notify->gt_grpmems;
	else
	    route_reply->out_vif_bm = 0;
    } else if (find_src_grp(route_query->source_addr.s_addr, 0,
			    route_query->dest_addr.s_addr)) {

	/* Found kernel entry. Code taken from add_table_entry() */
	gt = gtp ? gtp->gt_gnext : kernel_table;
	
	/* Include the routing entry. */
	route_reply->in_vif = gt->gt_route->rt_parent;
	route_reply->out_vif_bm = gt->gt_grpmems;

	/* Cache reply if using route change notification. */
	if BIT_TST(flags,RSRR_NOTIFICATION_BIT) {
	    rsrr_cache(gt,route_query);
	    BIT_SET(rsrr->flags,RSRR_NOTIFICATION_BIT);
	}
	
    } else {
	/* No kernel entry; use routing table. */
	r = determine_route(route_query->source_addr.s_addr);
	
	if (r != NULL) {
	    /* We need to mimic what will happen if a data packet
	     * is forwarded by multicast routing -- the kernel will
	     * make an upcall and mrouted will install a route in the kernel.
	     * Our outgoing vif bitmap should reflect what that table
	     * will look like.  Grab code from add_table_entry().
	     * This is gross, but it's probably better to be accurate.
	     */
	    
	    gt = &local_g;
	    mcastgrp = route_query->dest_addr.s_addr;
	    
	    gt->gt_mcastgrp    	= mcastgrp;
	    gt->gt_grpmems	= 0;
	    gt->gt_scope	= 0;
	    gt->gt_route        = r;
	    
	    /* obtain the multicast group membership list */
	    determine_forwvifs(gt);
	    
	    /* Include the routing entry. */
	    route_reply->in_vif = gt->gt_route->rt_parent;
	    route_reply->out_vif_bm = gt->gt_grpmems;

	} else {
	    /* Set error bit. */
	    BIT_SET(rsrr->flags,RSRR_ERROR_BIT);
	}
    }
    
    IF_DEBUG(DEBUG_RSRR)
    log(LOG_DEBUG, 0, "%sSend RSRR Route Reply for src %s dst %s in vif %d out vif %d\n",
	gt_notify ? "Route Change: " : "",
	inet_fmt(route_reply->source_addr.s_addr,s1),
	inet_fmt(route_reply->dest_addr.s_addr,s2),
	route_reply->in_vif,route_reply->out_vif_bm);
    
    /* Send it. */
    return rsrr_send(sendlen);
}

/* Send an RSRR message. */
static int
rsrr_send(int sendlen)
{
    int error;
    
    /* Send it. */
    error = sendto(rsrr_socket, rsrr_send_buf, sendlen, 0,
		   (struct sockaddr *)&client_addr, client_length);
    
    /* Check for errors. */
    if (error < 0) {
	log(LOG_WARNING, errno, "Failed send on RSRR socket");
    } else if (error != sendlen) {
	log(LOG_WARNING, 0,
	    "Sent only %d out of %d bytes on RSRR socket\n", error, sendlen);
    }
    return error;
}

/* Cache a message being sent to a client.  Currently only used for
 * caching Route Reply messages for route change notification.
 */
static void
rsrr_cache(struct gtable *gt, struct rsrr_rq *route_query)
{
    struct rsrr_cache *rc, **rcnp;
    struct rsrr_header *rsrr;

    rsrr = (struct rsrr_header *) rsrr_send_buf;

    rcnp = &gt->gt_rsrr_cache;
    while ((rc = *rcnp) != NULL) {
	if ((rc->route_query.source_addr.s_addr == 
	     route_query->source_addr.s_addr) &&
	    (rc->route_query.dest_addr.s_addr == 
	     route_query->dest_addr.s_addr) &&
	    (!strcmp(rc->client_addr.sun_path,client_addr.sun_path))) {
	    /* Cache entry already exists.
	     * Check if route notification bit has been cleared.
	     */
	    if (!BIT_TST(rsrr->flags,RSRR_NOTIFICATION_BIT)) {
		/* Delete cache entry. */
		*rcnp = rc->next;
		free(rc);
	    } else {
		/* Update */
		rc->route_query.query_id = route_query->query_id;
		IF_DEBUG(DEBUG_RSRR)
		log(LOG_DEBUG, 0,
			"Update cached query id %ld from client %s\n",
			rc->route_query.query_id, rc->client_addr.sun_path);
	    }
	    return;
	}
	rcnp = &rc->next;
    }

    /* Cache entry doesn't already exist.  Create one and insert at
     * front of list.
     */
    rc = (struct rsrr_cache *) malloc(sizeof(struct rsrr_cache));
    if (rc == NULL)
	log(LOG_ERR, 0, "ran out of memory");
    rc->route_query.source_addr.s_addr = route_query->source_addr.s_addr;
    rc->route_query.dest_addr.s_addr = route_query->dest_addr.s_addr;
    rc->route_query.query_id = route_query->query_id;
    strcpy(rc->client_addr.sun_path, client_addr.sun_path);
    rc->client_length = client_length;
    rc->next = gt->gt_rsrr_cache;
    gt->gt_rsrr_cache = rc;
    IF_DEBUG(DEBUG_RSRR)
    log(LOG_DEBUG, 0, "Cached query id %ld from client %s\n",
	   rc->route_query.query_id,rc->client_addr.sun_path);
}

/* Send all the messages in the cache.  Currently this is used to send
 * all the cached Route Reply messages for route change notification.
 */
void
rsrr_cache_send(struct gtable *gt, int notify)
{
    struct rsrr_cache *rc, **rcnp;
    int flags = 0;

    if (notify)
	BIT_SET(flags,RSRR_NOTIFICATION_BIT);

    rcnp = &gt->gt_rsrr_cache;
    while ((rc = *rcnp) != NULL) {
	if (rsrr_accept_rq(&rc->route_query,flags,gt) < 0) {
	    IF_DEBUG(DEBUG_RSRR)
	    log(LOG_DEBUG, 0, "Deleting cached query id %ld from client %s\n",
		   rc->route_query.query_id,rc->client_addr.sun_path);
	    /* Delete cache entry. */
	    *rcnp = rc->next;
	    free(rc);
	} else {
	    rcnp = &rc->next;
	}
    }
}

/* Clean the cache by deleting all entries. */
void
rsrr_cache_clean(struct gtable *gt)
{
    struct rsrr_cache *rc, *rc_next;

    IF_DEBUG(DEBUG_RSRR)
    log(LOG_DEBUG, 0, "cleaning cache for group %s\n",
			inet_fmt(gt->gt_mcastgrp, s1));
    rc = gt->gt_rsrr_cache;
    while (rc) {
	rc_next = rc->next;
	free(rc);
	rc = rc_next;
    }
    gt->gt_rsrr_cache = NULL;
}

void
rsrr_clean(void)
{
    unlink(RSRR_SERV_PATH);
}

#endif /* RSRR */