NetBSD-5.0.2/dist/ipf/ipsend/ip.c
/* $NetBSD: ip.c,v 1.8 2007/04/14 20:34:22 martin Exp $ */
/*
* ip.c (C) 1995-1998 Darren Reed
*
* See the IPFILTER.LICENCE file for details on licencing.
*/
#if !defined(lint)
static const char sccsid[] = "%W% %G% (C)1995";
static const char rcsid[] = "@(#)Id: ip.c,v 2.8.2.2 2007/02/17 12:41:51 darrenr Exp";
#endif
#include <sys/param.h>
#include <sys/types.h>
#include <netinet/in_systm.h>
#include <sys/socket.h>
#ifdef __osf__
# include "radix_ipf_local.h"
#endif
#include <net/if.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <sys/param.h>
#ifndef linux
# include <netinet/if_ether.h>
# include <netinet/ip_var.h>
# if __FreeBSD_version >= 300000
# include <net/if_var.h>
# endif
#endif
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include "ipsend.h"
static char *ipbuf = NULL, *ethbuf = NULL;
u_short chksum(buf,len)
u_short *buf;
int len;
{
u_long sum = 0;
int nwords = len >> 1;
for(; nwords > 0; nwords--)
sum += *buf++;
sum = (sum>>16) + (sum & 0xffff);
sum += (sum >>16);
return (~sum);
}
int send_ether(nfd, buf, len, gwip)
int nfd, len;
char *buf;
struct in_addr gwip;
{
static struct in_addr last_gw;
static char last_arp[6] = { 0, 0, 0, 0, 0, 0};
ether_header_t *eh;
char *s;
int err;
if (!ethbuf)
ethbuf = (char *)calloc(1, 65536+1024);
s = ethbuf;
eh = (ether_header_t *)s;
bcopy((char *)buf, s + sizeof(*eh), len);
if (gwip.s_addr == last_gw.s_addr)
{
bcopy(last_arp, (char *)A_A eh->ether_dhost, 6);
}
else if (arp((char *)&gwip, (char *)A_A eh->ether_dhost) == -1)
{
perror("arp");
return -2;
}
eh->ether_type = htons(ETHERTYPE_IP);
last_gw.s_addr = gwip.s_addr;
err = sendip(nfd, s, sizeof(*eh) + len);
return err;
}
/*
*/
int send_ip(nfd, mtu, ip, gwip, frag)
int nfd, mtu;
ip_t *ip;
struct in_addr gwip;
int frag;
{
static struct in_addr last_gw, local_ip;
static char local_arp[6] = { 0, 0, 0, 0, 0, 0};
static char last_arp[6] = { 0, 0, 0, 0, 0, 0};
static u_short id = 0;
ether_header_t *eh;
ip_t ipsv;
int err, iplen;
if (!ipbuf)
{
ipbuf = (char *)malloc(65536);
if (!ipbuf)
{
perror("malloc failed");
return -2;
}
}
eh = (ether_header_t *)ipbuf;
bzero((char *)A_A eh->ether_shost, sizeof(eh->ether_shost));
if (last_gw.s_addr && (gwip.s_addr == last_gw.s_addr))
{
bcopy(last_arp, (char *)A_A eh->ether_dhost, 6);
}
else if (arp((char *)&gwip, (char *)A_A eh->ether_dhost) == -1)
{
perror("arp");
return -2;
}
bcopy((char *)A_A eh->ether_dhost, last_arp, sizeof(last_arp));
eh->ether_type = htons(ETHERTYPE_IP);
bcopy((char *)ip, (char *)&ipsv, sizeof(*ip));
last_gw.s_addr = gwip.s_addr;
iplen = ip->ip_len;
ip->ip_len = htons(iplen);
if (!(frag & 2)) {
if (!IP_V(ip))
IP_V_A(ip, IPVERSION);
if (!ip->ip_id)
ip->ip_id = htons(id++);
if (!ip->ip_ttl)
ip->ip_ttl = 60;
}
if (ip->ip_src.s_addr != local_ip.s_addr) {
(void) arp((char *)&ip->ip_src, (char *)A_A local_arp);
bcopy(local_arp, (char *)A_A eh->ether_shost,sizeof(last_arp));
local_ip = ip->ip_src;
} else
bcopy(local_arp, (char *)A_A eh->ether_shost, 6);
if (!frag || (sizeof(*eh) + iplen < mtu))
{
ip->ip_sum = 0;
ip->ip_sum = chksum((u_short *)ip, IP_HL(ip) << 2);
bcopy((char *)ip, ipbuf + sizeof(*eh), iplen);
err = sendip(nfd, ipbuf, sizeof(*eh) + iplen);
}
else
{
/*
* Actually, this is bogus because we're putting all IP
* options in every packet, which isn't always what should be
* done. Will do for now.
*/
ether_header_t eth;
char optcpy[48], ol;
char *s;
int i, sent = 0, ts, hlen, olen;
hlen = IP_HL(ip) << 2;
if (mtu < (hlen + 8)) {
fprintf(stderr, "mtu (%d) < ip header size (%d) + 8\n",
mtu, hlen);
fprintf(stderr, "can't fragment data\n");
return -2;
}
ol = (IP_HL(ip) << 2) - sizeof(*ip);
for (i = 0, s = (char*)(ip + 1); ol > 0; )
if (*s == IPOPT_EOL) {
optcpy[i++] = *s;
break;
} else if (*s == IPOPT_NOP) {
s++;
ol--;
} else
{
olen = (int)(*(u_char *)(s + 1));
ol -= olen;
if (IPOPT_COPIED(*s))
{
bcopy(s, optcpy + i, olen);
i += olen;
s += olen;
}
}
if (i)
{
/*
* pad out
*/
while ((i & 3) && (i & 3) != 3)
optcpy[i++] = IPOPT_NOP;
if ((i & 3) == 3)
optcpy[i++] = IPOPT_EOL;
}
bcopy((char *)eh, (char *)ð, sizeof(eth));
s = (char *)ip + hlen;
iplen = ntohs(ip->ip_len) - hlen;
ip->ip_off |= htons(IP_MF);
while (1)
{
if ((sent + (mtu - hlen)) >= iplen)
{
ip->ip_off ^= htons(IP_MF);
ts = iplen - sent;
}
else
ts = (mtu - hlen);
ip->ip_off &= htons(0xe000);
ip->ip_off |= htons(sent >> 3);
ts += hlen;
ip->ip_len = htons(ts);
ip->ip_sum = 0;
ip->ip_sum = chksum((u_short *)ip, hlen);
bcopy((char *)ip, ipbuf + sizeof(*eh), hlen);
bcopy(s + sent, ipbuf + sizeof(*eh) + hlen, ts - hlen);
err = sendip(nfd, ipbuf, sizeof(*eh) + ts);
bcopy((char *)ð, ipbuf, sizeof(eth));
sent += (ts - hlen);
if (!(ntohs(ip->ip_off) & IP_MF))
break;
else if (!(ip->ip_off & htons(0x1fff)))
{
hlen = i + sizeof(*ip);
IP_HL_A(ip, (sizeof(*ip) + i) >> 2);
bcopy(optcpy, (char *)(ip + 1), i);
}
}
}
bcopy((char *)&ipsv, (char *)ip, sizeof(*ip));
return err;
}
/*
* send a tcp packet.
*/
int send_tcp(nfd, mtu, ip, gwip)
int nfd, mtu;
ip_t *ip;
struct in_addr gwip;
{
static tcp_seq iss = 2;
tcphdr_t *t, *t2;
int thlen, i, iplen, hlen;
u_32_t lbuf[20];
ip_t *ip2;
iplen = ip->ip_len;
hlen = IP_HL(ip) << 2;
t = (tcphdr_t *)((char *)ip + hlen);
ip2 = (struct ip *)lbuf;
t2 = (tcphdr_t *)((char *)ip2 + hlen);
thlen = TCP_OFF(t) << 2;
if (!thlen)
thlen = sizeof(tcphdr_t);
bzero((char *)ip2, sizeof(*ip2) + sizeof(*t2));
ip->ip_p = IPPROTO_TCP;
ip2->ip_p = ip->ip_p;
ip2->ip_src = ip->ip_src;
ip2->ip_dst = ip->ip_dst;
bcopy((char *)ip + hlen, (char *)t2, thlen);
if (!t2->th_win)
t2->th_win = htons(4096);
iss += 63;
i = sizeof(struct tcpiphdr) / sizeof(long);
if ((t2->th_flags == TH_SYN) && !ntohs(ip->ip_off) &&
(lbuf[i] != htonl(0x020405b4))) {
lbuf[i] = htonl(0x020405b4);
bcopy((char *)ip + hlen + thlen, (char *)ip + hlen + thlen + 4,
iplen - thlen - hlen);
thlen += 4;
}
TCP_OFF_A(t2, thlen >> 2);
ip2->ip_len = htons(thlen);
ip->ip_len = hlen + thlen;
t2->th_sum = 0;
t2->th_sum = chksum((u_short *)ip2, thlen + sizeof(ip_t));
bcopy((char *)t2, (char *)ip + hlen, thlen);
return send_ip(nfd, mtu, ip, gwip, 1);
}
/*
* send a udp packet.
*/
int send_udp(nfd, mtu, ip, gwip)
int nfd, mtu;
ip_t *ip;
struct in_addr gwip;
{
struct tcpiphdr *ti;
int thlen;
u_long lbuf[20];
ti = (struct tcpiphdr *)lbuf;
bzero((char *)ti, sizeof(*ti));
thlen = sizeof(udphdr_t);
ti->ti_pr = ip->ip_p;
ti->ti_src = ip->ip_src;
ti->ti_dst = ip->ip_dst;
bcopy((char *)ip + (IP_HL(ip) << 2),
(char *)&ti->ti_sport, sizeof(udphdr_t));
ti->ti_len = htons(thlen);
ip->ip_len = (IP_HL(ip) << 2) + thlen;
ti->ti_sum = 0;
ti->ti_sum = chksum((u_short *)ti, thlen + sizeof(ip_t));
bcopy((char *)&ti->ti_sport,
(char *)ip + (IP_HL(ip) << 2), sizeof(udphdr_t));
return send_ip(nfd, mtu, ip, gwip, 1);
}
/*
* send an icmp packet.
*/
int send_icmp(nfd, mtu, ip, gwip)
int nfd, mtu;
ip_t *ip;
struct in_addr gwip;
{
struct icmp *ic;
ic = (struct icmp *)((char *)ip + (IP_HL(ip) << 2));
ic->icmp_cksum = 0;
ic->icmp_cksum = chksum((u_short *)ic, sizeof(struct icmp));
return send_ip(nfd, mtu, ip, gwip, 1);
}
int send_packet(nfd, mtu, ip, gwip)
int nfd, mtu;
ip_t *ip;
struct in_addr gwip;
{
switch (ip->ip_p)
{
case IPPROTO_TCP :
return send_tcp(nfd, mtu, ip, gwip);
case IPPROTO_UDP :
return send_udp(nfd, mtu, ip, gwip);
case IPPROTO_ICMP :
return send_icmp(nfd, mtu, ip, gwip);
default :
return send_ip(nfd, mtu, ip, gwip, 1);
}
}