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/* $NetBSD: ip.c,v 1.2 2011/05/13 23:35:09 nakayama Exp $ */
/*
* Copyright (c) 1992 Regents of the University of California.
* Copyright (c) 2010 Zoltan Arnold NAGY
* 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.
*
*/
#include <sys/param.h>
#include <sys/socket.h>
#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>
#ifdef _STANDALONE
#include <lib/libkern/libkern.h>
#else
#include <string.h>
#endif
#include "stand.h"
#include "net.h"
/*
* sends an IP packet, if it's alredy constructed
*/
static ssize_t
_sendip(struct iodesc * d, struct ip * ip, size_t len)
{
u_char *ea;
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);
}
return sendether(d, ip, len, ea, ETHERTYPE_IP);
}
/*
* fills out the IP header
* Caller must leave room for ethernet, ip and udp headers in front!
*/
ssize_t
sendip(struct iodesc * d, void *pkt, size_t len, u_int8_t proto)
{
ssize_t cc;
struct ip *ip;
ip = (struct ip *) pkt - 1;
len += sizeof(*ip);
(void) memset(ip, 0, sizeof(*ip));
ip->ip_v = IPVERSION;
ip->ip_hl = sizeof(*ip) >> 2;
ip->ip_len = htons(len);
ip->ip_p = proto;
ip->ip_ttl = IPDEFTTL;
ip->ip_src = d->myip;
ip->ip_dst = d->destip;
ip->ip_sum = ip_cksum(ip, sizeof(*ip));
cc = _sendip(d, ip, len);
if (cc == -1)
return -1;
if ((size_t) cc != len)
panic("sendip: bad write (%zd != %zu)", cc, len);
return (cc - (sizeof(*ip)));
}
/*
* reads an IP packet
* WARNING: the old version stripped the IP options, if there were
* any. Because we have absolutely no idea if the upper layer needs
* these or not, it's best to leave them there.
*
* The size returned is the size indicated in the header.
*/
ssize_t
readip(struct iodesc * d, void *pkt, size_t len, time_t tleft, u_int8_t proto)
{
ssize_t n;
size_t hlen;
struct ip *ip;
u_int16_t etype;
ip = (struct ip *) pkt - 1;
n = readether(d, ip, len + sizeof(*ip), tleft, &etype);
if (n == -1 || (size_t) n < sizeof(*ip))
return -1;
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("readip: not IP. ether_type=%x\n", etype);
#endif
return -1;
}
/* Check ip header */
if (ip->ip_v != IPVERSION ||
ip->ip_p != proto) { /* half char */
#ifdef NET_DEBUG
if (debug) {
printf("readip: wrong IP version or wrong proto "
"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) || ip_cksum(ip, hlen) != 0) {
#ifdef NET_DEBUG
if (debug)
printf("readip: short hdr or bad cksum.\n");
#endif
return -1;
}
if (n < ntohs(ip->ip_len)) {
#ifdef NET_DEBUG
if (debug)
printf("readip: bad length %d < %d.\n",
(int) 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("readip: bad saddr %s != ", inet_ntoa(d->myip));
printf("%s\n", inet_ntoa(ip->ip_dst));
}
#endif
return -1;
}
return (ntohs(ip->ip_len) - 20);
}
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