191 lines
5.2 KiB
C
191 lines
5.2 KiB
C
/* $NetBSD: ip.c,v 1.2 2011/05/13 23:35:09 nakayama Exp $ */
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/*
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* Copyright (c) 1992 Regents of the University of California.
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* Copyright (c) 2010 Zoltan Arnold NAGY
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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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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Lawrence Berkeley Laboratory and its contributors.
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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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*/
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#include <sys/param.h>
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#include <sys/socket.h>
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#include <net/if.h>
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#include <net/if_ether.h>
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#include <netinet/in.h>
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#include <netinet/in_systm.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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#ifdef _STANDALONE
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#include <lib/libkern/libkern.h>
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#else
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#include <string.h>
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#endif
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#include "stand.h"
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#include "net.h"
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/*
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* sends an IP packet, if it's alredy constructed
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*/
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static ssize_t
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_sendip(struct iodesc * d, struct ip * ip, size_t len)
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{
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u_char *ea;
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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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}
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return sendether(d, ip, len, ea, ETHERTYPE_IP);
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}
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/*
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* fills out the IP header
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* Caller must leave room for ethernet, ip and udp headers in front!
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*/
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ssize_t
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sendip(struct iodesc * d, void *pkt, size_t len, u_int8_t proto)
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{
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ssize_t cc;
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struct ip *ip;
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ip = (struct ip *) pkt - 1;
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len += sizeof(*ip);
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(void) memset(ip, 0, sizeof(*ip));
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ip->ip_v = IPVERSION;
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ip->ip_hl = sizeof(*ip) >> 2;
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ip->ip_len = htons(len);
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ip->ip_p = proto;
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ip->ip_ttl = IPDEFTTL;
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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 = ip_cksum(ip, sizeof(*ip));
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cc = _sendip(d, ip, len);
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if (cc == -1)
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return -1;
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if ((size_t) cc != len)
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panic("sendip: bad write (%zd != %zu)", cc, len);
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return (cc - (sizeof(*ip)));
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}
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/*
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* reads an IP packet
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* WARNING: the old version stripped the IP options, if there were
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* any. Because we have absolutely no idea if the upper layer needs
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* these or not, it's best to leave them there.
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*
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* The size returned is the size indicated in the header.
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*/
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ssize_t
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readip(struct iodesc * d, void *pkt, size_t len, time_t tleft, u_int8_t proto)
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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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u_int16_t etype;
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ip = (struct ip *) pkt - 1;
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n = readether(d, ip, len + sizeof(*ip), tleft, &etype);
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if (n == -1 || (size_t) n < sizeof(*ip))
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return -1;
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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("readip: 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 != proto) { /* half char */
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#ifdef NET_DEBUG
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if (debug) {
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printf("readip: wrong IP version or wrong proto "
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"ip_v=%d ip_p=%d\n", ip->ip_v, ip->ip_p);
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}
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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) || ip_cksum(ip, hlen) != 0) {
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#ifdef NET_DEBUG
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if (debug)
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printf("readip: 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("readip: 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("readip: 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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return (ntohs(ip->ip_len) - 20);
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}
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