273 lines
6.8 KiB
C
273 lines
6.8 KiB
C
/* Taken from $NetBSD: net.c,v 1.20 1997/12/26 22:41:30 scottr Exp $ */
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/*
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* Copyright (c) 1992 Regents of the University of California.
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* All rights reserved.
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*
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* This software was developed by the Computer Systems Engineering group
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* at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
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* contributed to Berkeley.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#) Header: net.c,v 1.9 93/08/06 19:32:15 leres Exp (LBL)
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/socket.h>
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#include <string.h>
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#include <net/if.h>
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#include <netinet/in.h>
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#include <netinet/if_ether.h>
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#include <netinet/in_systm.h>
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#include <netinet/in_pcb.h>
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#include <netinet/ip.h>
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#include <netinet/ip_var.h>
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#include <netinet/udp.h>
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#include <netinet/udp_var.h>
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#include "stand.h"
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#include "net.h"
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/* Caller must leave room for ethernet, ip and udp headers in front!! */
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ssize_t
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sendudp(d, pkt, len)
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struct iodesc *d;
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void *pkt;
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size_t len;
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{
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ssize_t cc;
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struct ip *ip;
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struct udphdr *uh;
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u_char *ea;
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#ifdef NET_DEBUG
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if (debug) {
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printf("sendudp: d=%lx called.\n", (long)d);
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if (d) {
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printf("saddr: %s:%d",
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inet_ntoa(d->myip), ntohs(d->myport));
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printf(" daddr: %s:%d\n",
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inet_ntoa(d->destip), ntohs(d->destport));
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}
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}
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#endif
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uh = (struct udphdr *)pkt - 1;
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ip = (struct ip *)uh - 1;
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len += sizeof(*ip) + sizeof(*uh);
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bzero(ip, sizeof(*ip) + sizeof(*uh));
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ip->ip_v = IPVERSION; /* half-char */
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ip->ip_hl = sizeof(*ip) >> 2; /* half-char */
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ip->ip_len = htons(len);
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ip->ip_p = IPPROTO_UDP; /* char */
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ip->ip_ttl = IPDEFTTL; /* char */
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ip->ip_src = d->myip;
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ip->ip_dst = d->destip;
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ip->ip_sum = in_cksum(ip, sizeof(*ip)); /* short, but special */
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uh->uh_sport = d->myport;
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uh->uh_dport = d->destport;
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uh->uh_ulen = htons(len - sizeof(*ip));
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#ifndef UDP_NO_CKSUM
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{
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struct udpiphdr *ui;
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struct ip tip;
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/* Calculate checksum (must save and restore ip header) */
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tip = *ip;
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ui = (struct udpiphdr *)ip;
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bzero(&ui->ui_x1, sizeof(ui->ui_x1));
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ui->ui_len = uh->uh_ulen;
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uh->uh_sum = in_cksum(ui, len);
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*ip = tip;
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}
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#endif
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if (ip->ip_dst.s_addr == INADDR_BROADCAST || ip->ip_src.s_addr == 0 ||
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netmask == 0 || SAMENET(ip->ip_src, ip->ip_dst, netmask))
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ea = arpwhohas(d, ip->ip_dst);
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else
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ea = arpwhohas(d, gateip);
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cc = sendether(d, ip, len, ea, ETHERTYPE_IP);
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if (cc == -1)
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return (-1);
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if (cc != len)
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panic("sendudp: bad write (%zd != %zd)", cc, len);
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return (cc - (sizeof(*ip) + sizeof(*uh)));
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}
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/*
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* Receive a UDP packet and validate it is for us.
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* Caller leaves room for the headers (Ether, IP, UDP)
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*/
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ssize_t
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readudp(d, pkt, len, tleft)
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struct iodesc *d;
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void *pkt;
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size_t len;
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time_t tleft;
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{
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ssize_t n;
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size_t hlen;
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struct ip *ip;
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struct udphdr *uh;
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u_int16_t etype; /* host order */
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#ifdef NET_DEBUG
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if (debug)
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printf("readudp: called\n");
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#endif
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uh = (struct udphdr *)pkt - 1;
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ip = (struct ip *)uh - 1;
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n = readether(d, ip, len + sizeof(*ip) + sizeof(*uh), tleft, &etype);
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if (n == -1 || n < sizeof(*ip) + sizeof(*uh))
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return -1;
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/* Ethernet address checks now in readether() */
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/* Need to respond to ARP requests. */
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if (etype == ETHERTYPE_ARP) {
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struct arphdr *ah = (void *)ip;
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if (ah->ar_op == htons(ARPOP_REQUEST)) {
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/* Send ARP reply */
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arp_reply(d, ah);
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}
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return -1;
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}
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if (etype != ETHERTYPE_IP) {
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#ifdef NET_DEBUG
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if (debug)
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printf("readudp: not IP. ether_type=%x\n", etype);
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#endif
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return -1;
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}
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/* Check ip header */
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if (ip->ip_v != IPVERSION ||
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ip->ip_p != IPPROTO_UDP) { /* half char */
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#ifdef NET_DEBUG
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if (debug)
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printf("readudp: IP version or not UDP. ip_v=%d ip_p=%d\n", ip->ip_v, ip->ip_p);
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#endif
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return -1;
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}
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hlen = ip->ip_hl << 2;
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if (hlen < sizeof(*ip) ||
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in_cksum(ip, hlen) != 0) {
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#ifdef NET_DEBUG
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if (debug)
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printf("readudp: short hdr or bad cksum.\n");
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#endif
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return -1;
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}
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if (n < ntohs(ip->ip_len)) {
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#ifdef NET_DEBUG
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if (debug)
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printf("readudp: bad length %d < %d.\n",
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(int)n, ntohs(ip->ip_len));
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#endif
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return -1;
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}
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if (d->myip.s_addr && ip->ip_dst.s_addr != d->myip.s_addr) {
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#ifdef NET_DEBUG
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if (debug) {
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printf("readudp: bad saddr %s != ", inet_ntoa(d->myip));
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printf("%s\n", inet_ntoa(ip->ip_dst));
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}
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#endif
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return -1;
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}
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/* If there were ip options, make them go away */
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if (hlen != sizeof(*ip)) {
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bcopy(((u_char *)ip) + hlen, uh, len - hlen);
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ip->ip_len = htons(sizeof(*ip));
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n -= hlen - sizeof(*ip);
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}
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if (uh->uh_dport != d->myport) {
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#ifdef NET_DEBUG
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if (debug)
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printf("readudp: bad dport %d != %d\n",
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d->myport, ntohs(uh->uh_dport));
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#endif
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return -1;
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}
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#ifndef UDP_NO_CKSUM
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if (uh->uh_sum) {
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struct udpiphdr *ui;
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struct ip tip;
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n = ntohs(uh->uh_ulen) + sizeof(*ip);
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if (n > RECV_SIZE - ETHER_SIZE) {
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printf("readudp: huge packet, udp len %d\n", (int)n);
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return -1;
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}
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/* Check checksum (must save and restore ip header) */
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tip = *ip;
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ui = (struct udpiphdr *)ip;
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bzero(&ui->ui_x1, sizeof(ui->ui_x1));
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ui->ui_len = uh->uh_ulen;
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if (in_cksum(ui, n) != 0) {
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#ifdef NET_DEBUG
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if (debug)
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printf("readudp: bad cksum\n");
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#endif
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*ip = tip;
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return -1;
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}
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*ip = tip;
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}
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#endif
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if (ntohs(uh->uh_ulen) < sizeof(*uh)) {
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#ifdef NET_DEBUG
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if (debug)
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printf("readudp: bad udp len %d < %d\n",
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ntohs(uh->uh_ulen), (int)sizeof(*uh));
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#endif
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return -1;
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}
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n = (n > (ntohs(uh->uh_ulen) - sizeof(*uh))) ?
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ntohs(uh->uh_ulen) - sizeof(*uh) : n;
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return (n);
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}
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