/*      $NetBSD: udp.c,v 1.13 2019/03/31 20:08:45 christos Exp $        */

/*
* Copyright (c) 1992 Regents of the University of California.
* All rights reserved.
*
* This software was developed by the Computer Systems Engineering group
* at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
* contributed to Berkeley.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
*    must display the following acknowledgement:
*      This product includes software developed by the University of
*      California, Lawrence Berkeley Laboratory and its contributors.
* 4. Neither the name of the University nor the names of its contributors
*    may be used to endorse or promote products derived from this software
*    without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#) Header: net.c,v 1.9 93/08/06 19:32:15 leres Exp  (LBL)
*/

#include <sys/param.h>
#include <sys/socket.h>

#ifdef _STANDALONE
#include <lib/libkern/libkern.h>
#else
#include <string.h>
#endif

#include <net/if.h>
#include <net/if_ether.h>

#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/ip_var.h>
#include <netinet/udp.h>
#include <netinet/udp_var.h>

#include "stand.h"
#include "net.h"


/* Caller must leave room for ethernet, ip and udp headers in front!! */
ssize_t
sendudp(struct iodesc *d, void *pkt, size_t len)
{
       ssize_t cc;
       struct udphdr *uh;

#ifdef NET_DEBUG
       if (debug) {
               printf("%s: d=%p called.\n", __func__, d);
               if (d) {
                       printf("saddr: %s:%d",
                           inet_ntoa(d->myip), ntohs(d->myport));
                       printf(" daddr: %s:%d\n",
                           inet_ntoa(d->destip), ntohs(d->destport));
               }
       }
#endif

       uh = (struct udphdr *)pkt - 1;
       len += sizeof(*uh);

       (void)memset(uh, 0, sizeof(*uh));

       uh->uh_sport = d->myport;
       uh->uh_dport = d->destport;
       uh->uh_ulen = htons(len);

       cc = sendip(d, uh, len, IPPROTO_UDP);
       if (cc == -1)
               return -1;
       if ((size_t)cc != len)
               panic("%s: bad write (%zd != %zu)", __func__, cc, len);
       return (cc - sizeof(*uh));
}

/*
* Receive a UDP packet and validate it is for us.
* Caller leaves room for the headers (Ether, IP, UDP)
*/
ssize_t
readudp(struct iodesc *d, void *pkt, size_t len, saseconds_t tleft)
{
       ssize_t n;
       struct udphdr *uh;

       uh = (struct udphdr *)pkt - 1;
       n = readip(d, uh, len + sizeof(*uh), tleft, IPPROTO_UDP);
       if (n == -1 || (size_t)n < sizeof(*uh))
               return -1;

       if (uh->uh_dport != d->myport) {
#ifdef NET_DEBUG
               if (debug)
                       printf("%s: bad dport %d != %d\n", __func__,
                           ntohs(d->myport), ntohs(uh->uh_dport));
#endif
               return -1;
       }

       if (ntohs(uh->uh_ulen) < sizeof(*uh)) {
#ifdef NET_DEBUG
               if (debug)
                       printf("%s: bad udp len %d < %zu\n", __func__,
                               ntohs(uh->uh_ulen), sizeof(*uh));
#endif
               return -1;
       }

       n -= sizeof(*uh);
       return n;
}