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/* $OpenBSD: netudp.c,v 1.4 2018/03/31 17:09:56 patrick Exp $ */
/* $NetBSD: net.c,v 1.14 1996/10/13 02:29:02 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>
#include <net/if.h>
#include <netinet/in.h>
#include <netinet/if_ether.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 ip *ip;
struct udpiphdr *ui;
struct udphdr *uh;
u_char *ea;
struct ip tip;
#ifdef NET_DEBUG
if (debug) {
printf("sendudp: d=%x called.\n", (u_int)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;
ip = (struct ip *)uh - 1;
len += sizeof(*ip) + sizeof(*uh);
bzero(ip, sizeof(*ip) + sizeof(*uh));
ip->ip_v = IPVERSION; /* half-char */
ip->ip_hl = sizeof(*ip) >> 2; /* half-char */
ip->ip_len = htons(len);
ip->ip_p = IPPROTO_UDP; /* char */
ip->ip_ttl = IP_TTL; /* char */
ip->ip_src = d->myip;
ip->ip_dst = d->destip;
ip->ip_sum = in_cksum(ip, sizeof(*ip)); /* short, but special */
uh->uh_sport = d->myport;
uh->uh_dport = d->destport;
uh->uh_ulen = htons(len - sizeof(*ip));
/* Calculate checksum (must save and restore ip header) */
tip = *ip;
ui = (struct udpiphdr *)ip;
bzero(ui->ui_x1, sizeof(ui->ui_x1));
ui->ui_len = uh->uh_ulen;
uh->uh_sum = in_cksum(ui, len);
*ip = tip;
if (ip->ip_dst.s_addr == INADDR_BROADCAST || ip->ip_src.s_addr == 0 ||
netmask == 0 || SAMENET(ip->ip_src, ip->ip_dst, netmask))
ea = arpwhohas(d, ip->ip_dst);
else
ea = arpwhohas(d, gateip);
cc = sendether(d, ip, len, ea, ETHERTYPE_IP);
if (cc < 0)
return (-1);
if ((size_t)cc != len)
panic("sendudp: bad write (%d != %d)", cc, len);
return (cc - (sizeof(*ip) + 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, time_t tleft)
{
ssize_t n;
size_t hlen;
struct ip *ip;
struct udphdr *uh;
struct udpiphdr *ui;
struct ip tip;
u_int16_t etype; /* host order */
#ifdef NET_DEBUG
if (debug)
printf("readudp: called\n");
#endif
uh = (struct udphdr *)pkt - 1;
ip = (struct ip *)uh - 1;
n = readether(d, ip, len + sizeof(*ip) + sizeof(*uh), tleft, &etype);
if (n < 0 || (size_t)n < sizeof(*ip) + sizeof(*uh))
return -1;
/* Ethernet address checks now in readether() */
/* Need to respond to ARP requests. */
if (etype == ETHERTYPE_ARP) {
struct arphdr *ah = (void *)ip;
if (ah->ar_op == htons(ARPOP_REQUEST)) {
/* Send ARP reply */
arp_reply(d, ah);
}
return -1;
}
if (etype != ETHERTYPE_IP) {
#ifdef NET_DEBUG
if (debug)
printf("readudp: not IP. ether_type=%x\n", etype);
#endif
return -1;
}
/* Check ip header */
if (ip->ip_v != IPVERSION || ip->ip_p != IPPROTO_UDP) { /* half char */
#ifdef NET_DEBUG
if (debug)
printf("readudp: IP version or not UDP. ip_v=%d ip_p=%d\n", ip->ip_v, ip->ip_p);
#endif
return -1;
}
hlen = ip->ip_hl << 2;
if (hlen < sizeof(*ip) || in_cksum(ip, hlen) != 0) {
#ifdef NET_DEBUG
if (debug)
printf("readudp: short hdr or bad cksum.\n");
#endif
return -1;
}
if (n < ntohs(ip->ip_len)) {
#ifdef NET_DEBUG
if (debug)
printf("readudp: bad length %d < %d.\n",
n, ntohs(ip->ip_len));
#endif
return -1;
}
if (d->myip.s_addr && ip->ip_dst.s_addr != d->myip.s_addr) {
#ifdef NET_DEBUG
if (debug) {
printf("readudp: bad saddr %s != ", inet_ntoa(d->myip));
printf("%s\n", inet_ntoa(ip->ip_dst));
}
#endif
return -1;
}
/* If there were ip options, make them go away */
if (hlen != sizeof(*ip)) {
bcopy(((u_char *)ip) + hlen, uh, len - hlen);
ip->ip_len = htons(sizeof(*ip));
n -= hlen - sizeof(*ip);
}
if (uh->uh_dport != d->myport) {
#ifdef NET_DEBUG
if (debug)
printf("readudp: bad dport %d != %d\n",
d->myport, ntohs(uh->uh_dport));
#endif
return -1;
}
if (uh->uh_sum) {
n = ntohs(uh->uh_ulen) + sizeof(*ip);
if (n > RECV_SIZE - ETHER_SIZE) {
printf("readudp: huge packet, udp len %ld\n", (long)n);
return -1;
}
/* Check checksum (must save and restore ip header) */
tip = *ip;
ui = (struct udpiphdr *)ip;
bzero(ui->ui_x1, sizeof(ui->ui_x1));
ui->ui_len = uh->uh_ulen;
if (in_cksum(ui, n) != 0) {
#ifdef NET_DEBUG
if (debug)
printf("readudp: bad cksum\n");
#endif
*ip = tip;
return -1;
}
*ip = tip;
}
if (ntohs(uh->uh_ulen) < sizeof(*uh)) {
#ifdef NET_DEBUG
if (debug)
printf("readudp: bad udp len %d < %d\n",
ntohs(uh->uh_ulen), sizeof(*uh));
#endif
return -1;
}
n -= sizeof(*ip) + sizeof(*uh);
return (n);
}
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