358 lines
7.7 KiB
C
358 lines
7.7 KiB
C
/* $NetBSD: ip.c,v 1.2 2001/03/26 06:11:47 mike Exp $ */
|
|
|
|
/*
|
|
* ip.c (C) 1995-1998 Darren Reed
|
|
*
|
|
* Redistribution and use in source and binary forms are permitted
|
|
* provided that this notice is preserved and due credit is given
|
|
* to the original author and the contributors.
|
|
*/
|
|
#if !defined(lint)
|
|
static const char sccsid[] = "%W% %G% (C)1995";
|
|
static const char rcsid[] = "@(#)Id: ip.c,v 2.1.4.1 2001/01/10 06:21:19 darrenr Exp";
|
|
#endif
|
|
#include <errno.h>
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <unistd.h>
|
|
#include <string.h>
|
|
#include <sys/types.h>
|
|
#include <netinet/in_systm.h>
|
|
#include <sys/socket.h>
|
|
#include <net/if.h>
|
|
#include <netinet/in.h>
|
|
#include <netinet/ip.h>
|
|
#include <netinet/tcp.h>
|
|
#include <netinet/udp.h>
|
|
#include <netinet/ip_icmp.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 "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;
|
|
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->ip_v)
|
|
ip->ip_v = IPVERSION;
|
|
if (!ip->ip_id)
|
|
ip->ip_id = htons(id++);
|
|
if (!ip->ip_ttl)
|
|
ip->ip_ttl = 60;
|
|
}
|
|
|
|
if (!frag || (sizeof(*eh) + iplen < mtu))
|
|
{
|
|
ip->ip_sum = 0;
|
|
ip->ip_sum = chksum((u_short *)ip, ip->ip_hl << 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->ip_hl << 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->ip_hl << 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->ip_hl = (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;
|
|
struct tcpiphdr *ti;
|
|
tcphdr_t *t;
|
|
int thlen, i, iplen, hlen;
|
|
u_32_t lbuf[20];
|
|
|
|
iplen = ip->ip_len;
|
|
hlen = ip->ip_hl << 2;
|
|
t = (tcphdr_t *)((char *)ip + hlen);
|
|
ti = (struct tcpiphdr *)lbuf;
|
|
thlen = t->th_off << 2;
|
|
if (!thlen)
|
|
thlen = sizeof(tcphdr_t);
|
|
bzero((char *)ti, sizeof(*ti));
|
|
ip->ip_p = IPPROTO_TCP;
|
|
ti->ti_pr = ip->ip_p;
|
|
ti->ti_src = ip->ip_src;
|
|
ti->ti_dst = ip->ip_dst;
|
|
bcopy((char *)ip + hlen, (char *)&ti->ti_sport, thlen);
|
|
|
|
if (!ti->ti_win)
|
|
ti->ti_win = htons(4096);
|
|
iss += 63;
|
|
|
|
i = sizeof(struct tcpiphdr) / sizeof(long);
|
|
|
|
if ((ti->ti_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;
|
|
}
|
|
ti->ti_off = thlen >> 2;
|
|
ti->ti_len = htons(thlen);
|
|
ip->ip_len = hlen + thlen;
|
|
ti->ti_sum = 0;
|
|
ti->ti_sum = chksum((u_short *)ti, thlen + sizeof(ip_t));
|
|
|
|
bcopy((char *)&ti->ti_sport, (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->ip_hl << 2),
|
|
(char *)&ti->ti_sport, sizeof(udphdr_t));
|
|
|
|
ti->ti_len = htons(thlen);
|
|
ip->ip_len = (ip->ip_hl << 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->ip_hl << 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->ip_hl << 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);
|
|
}
|
|
}
|