409 lines
9.3 KiB
C
409 lines
9.3 KiB
C
/*
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* PPP IP Protocol Interface
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*
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* Written by Toshiharu OHNO (tony-o@iij.ad.jp)
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*
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* Copyright (C) 1993, Internet Initiative Japan, Inc. All rights reserverd.
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*
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* Redistribution and use in source and binary forms are permitted
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* provided that the above copyright notice and this paragraph are
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* duplicated in all such forms and that any documentation,
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* advertising materials, and other materials related to such
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* distribution and use acknowledge that the software was developed
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* by the Internet Initiative Japan. The name of the
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* IIJ may not be used to endorse or promote products derived
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* from this software without specific prior written permission.
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
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* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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*
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* $Id: ip.c,v 1.15 1997/04/21 01:01:45 brian Exp $
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*
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* TODO:
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* o Return ICMP message for filterd packet
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* and optionaly record it into log.
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*/
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#include "fsm.h"
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#include "lcpproto.h"
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#include "hdlc.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_icmp.h>
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#include <netinet/udp.h>
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#include <netinet/tcp.h>
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#include <arpa/inet.h>
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#include "vars.h"
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#include "filter.h"
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#include "alias.h"
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extern void SendPppFrame();
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extern void LcpClose();
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static struct pppTimer IdleTimer;
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static void IdleTimeout()
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{
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LogPrintf(LOG_PHASE_BIT, "Idle timer expired.\n");
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LcpClose();
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lostCarrier = 0;
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}
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/*
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* Start Idle timer. If timeout is reached, we call LcpClose() to
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* close LCP and link.
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*/
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void
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StartIdleTimer()
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{
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if (!(mode & (MODE_DEDICATED|MODE_DDIAL))) {
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StopTimer(&IdleTimer);
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IdleTimer.func = IdleTimeout;
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IdleTimer.load = VarIdleTimeout * SECTICKS;
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IdleTimer.state = TIMER_STOPPED;
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StartTimer(&IdleTimer);
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}
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}
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void
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StopIdleTimer()
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{
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StopTimer(&IdleTimer);
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}
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/*
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* If any IP layer traffic is detected, refresh IdleTimer.
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*/
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static void
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RestartIdleTimer()
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{
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if (!(mode & (MODE_DEDICATED|MODE_DDIAL)) && ipKeepAlive ) {
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StartTimer(&IdleTimer);
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ipIdleSecs = 0;
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}
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}
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static u_short interactive_ports[32] = {
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544, 513, 514, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 21, 22, 23, 0, 0, 0, 0, 0, 0, 0, 543,
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};
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#define INTERACTIVE(p) (interactive_ports[(p) & 0x1F] == (p))
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static char *TcpFlags[] = {
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"FIN", "SYN", "RST", "PSH", "ACK", "URG",
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};
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static char *Direction[] = { "INP", "OUT", "OUT", "IN/OUT" };
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static struct filterent *Filters[] = { ifilters, ofilters, dfilters, afilters };
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static int
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PortMatch(op, pport, rport)
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int op;
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u_short pport, rport;
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{
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switch (op) {
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case OP_EQ:
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return(pport == rport);
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case OP_GT:
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return(pport > rport);
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case OP_LT:
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return(pport < rport);
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default:
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return(0);
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}
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}
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/*
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* Check a packet against with defined filters
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*/
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static int
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FilterCheck(pip, direction)
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struct ip *pip;
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int direction;
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{
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struct filterent *fp = Filters[direction];
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int gotinfo, cproto, estab, n;
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struct tcphdr *th;
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struct udphdr *uh;
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struct icmp *ih;
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char *ptop;
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u_short sport, dport;
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if (fp->action) {
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cproto = gotinfo = estab = 0;
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sport = dport = 0;
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for (n = 0; n < MAXFILTERS; n++) {
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if (fp->action) {
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/* permit fragments on in and out filter */
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if ((direction == FL_IN || direction == FL_OUT) &&
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(ntohs(pip->ip_off) & IP_OFFMASK) != 0) {
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return(A_PERMIT);
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}
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#ifdef DEBUG
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logprintf("rule = %d\n", n);
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#endif
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if ((pip->ip_src.s_addr & fp->smask.s_addr) == fp->saddr.s_addr
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&& (pip->ip_dst.s_addr & fp->dmask.s_addr) == fp->daddr.s_addr) {
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if (fp->proto) {
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if (!gotinfo) {
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ptop = (char *)pip + (pip->ip_hl << 2);
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switch (pip->ip_p) {
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case IPPROTO_ICMP:
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cproto = P_ICMP; ih = (struct icmp *)ptop;
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sport = ih->icmp_type; estab = 1;
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break;
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case IPPROTO_UDP:
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cproto = P_UDP; uh = (struct udphdr *)ptop;
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sport = ntohs(uh->uh_sport); dport = ntohs(uh->uh_dport);
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estab = 1;
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break;
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case IPPROTO_TCP:
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cproto = P_TCP; th = (struct tcphdr *)ptop;
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sport = ntohs(th->th_sport); dport = ntohs(th->th_dport);
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estab = (th->th_flags & TH_ACK);
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#ifdef DEBUG
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if (estab == 0)
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logprintf("flag = %02x, sport = %d, dport = %d\n", th->th_flags, sport, dport);
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#endif
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break;
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default:
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return(A_DENY); /* We'll block unknown type of packet */
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}
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gotinfo = 1;
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#ifdef DEBUG
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logprintf("dir = %d, proto = %d, srcop = %d, dstop = %d, estab = %d\n",
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direction, cproto, fp->opt.srcop, fp->opt.dstop, estab);
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#endif
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}
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#ifdef DEBUG
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logprintf("check0: rule = %d, proto = %d, sport = %d, dport = %d\n",
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n, cproto, sport, dport);
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logprintf("check0: action = %d\n", fp->action);
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#endif
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if (cproto == fp->proto) {
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if ((fp->opt.srcop == OP_NONE ||
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PortMatch(fp->opt.srcop, sport, fp->opt.srcport))
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&&
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(fp->opt.dstop == OP_NONE ||
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PortMatch(fp->opt.dstop, dport, fp->opt.dstport))
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&&
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(fp->opt.estab == 0 || estab)) {
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return(fp->action);
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}
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}
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} else {
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/* Address is mached. Make a decision. */
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#ifdef DEBUG
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logprintf("check1: action = %d\n", fp->action);
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#endif
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return(fp->action);
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}
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}
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}
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fp++;
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}
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return(A_DENY); /* No rule is mached. Deny this packet */
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}
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return(A_PERMIT); /* No rule is given. Permit this packet */
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}
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static void
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IcmpError(pip, code)
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struct ip *pip;
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int code;
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{
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#ifdef notdef
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struct mbuf *bp;
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if (pip->ip_p != IPPROTO_ICMP) {
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bp = mballoc(cnt, MB_IPIN);
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bcopy(ptr, MBUF_CTOP(bp), cnt);
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SendPppFrame(bp);
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RestartIdleTimer();
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ipOutOctets += cnt;
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}
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#endif
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}
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/*
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* For debugging aid.
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*/
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int
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PacketCheck(cp, nb, direction)
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char *cp;
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int nb;
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int direction;
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{
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struct ip *pip;
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struct tcphdr *th;
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struct udphdr *uh;
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struct icmp *icmph;
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char *ptop;
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int mask, len, n;
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int logit;
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int pri = PRI_NORMAL;
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logit = (loglevel & (1 << LOG_TCPIP));
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pip = (struct ip *)cp;
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if (logit) logprintf("%s ", Direction[direction]);
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ptop = (cp + (pip->ip_hl << 2));
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switch (pip->ip_p) {
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case IPPROTO_ICMP:
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if (logit) {
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icmph = (struct icmp *)ptop;
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logprintf("ICMP: %s:%d ---> ", inet_ntoa(pip->ip_src), icmph->icmp_type);
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logprintf("%s:%d\n", inet_ntoa(pip->ip_dst), icmph->icmp_type);
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}
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break;
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case IPPROTO_UDP:
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if (logit) {
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uh = (struct udphdr *)ptop;
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logprintf("UDP: %s:%d ---> ", inet_ntoa(pip->ip_src), ntohs(uh->uh_sport));
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logprintf("%s:%d\n", inet_ntoa(pip->ip_dst), ntohs(uh->uh_dport));
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}
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break;
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case IPPROTO_TCP:
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th = (struct tcphdr *)ptop;
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if (pip->ip_tos == IPTOS_LOWDELAY)
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pri = PRI_FAST;
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else if ((ntohs(pip->ip_off) & IP_OFFMASK) == 0) {
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if (INTERACTIVE(ntohs(th->th_sport)) || INTERACTIVE(ntohs(th->th_dport)))
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pri = PRI_FAST;
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}
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if (logit) {
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len = ntohs(pip->ip_len) - (pip->ip_hl << 2) - (th->th_off << 2);
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logprintf("TCP: %s:%d ---> ", inet_ntoa(pip->ip_src), ntohs(th->th_sport));
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logprintf("%s:%d", inet_ntoa(pip->ip_dst), ntohs(th->th_dport));
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n = 0;
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for (mask = TH_FIN; mask != 0x40; mask <<= 1) {
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if (th->th_flags & mask)
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logprintf(" %s", TcpFlags[n]);
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n++;
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}
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logprintf(" seq:%x ack:%x (%d/%d)\n",
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ntohl(th->th_seq), ntohl(th->th_ack), len, nb);
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if ((th->th_flags & TH_SYN) && nb > 40) {
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u_short *sp;
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ptop += 20;
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sp = (u_short *)ptop;
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if (ntohs(sp[0]) == 0x0204)
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logprintf(" MSS = %d\n", ntohs(sp[1]));
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}
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}
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break;
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}
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if ((FilterCheck(pip, direction) & A_DENY)) {
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#ifdef DEBUG
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logprintf("blocked.\n");
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#endif
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if (direction == 0) IcmpError(pip, pri);
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return(-1);
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} else {
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if ( FilterCheck(pip, FL_KEEP ) & A_DENY ) { /* Check Keep Alive filter */
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ipKeepAlive = FALSE;
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} else {
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ipKeepAlive = TRUE;
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}
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return(pri);
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}
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}
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void
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IpInput(bp)
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struct mbuf *bp; /* IN: Pointer to IP pakcet */
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{
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u_char *cp;
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struct mbuf *wp;
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int nb, nw;
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u_char tunbuff[MAX_MRU];
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cp = tunbuff;
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nb = 0;
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for (wp = bp; wp; wp = wp->next) { /* Copy to continuois region */
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bcopy(MBUF_CTOP(wp), cp, wp->cnt);
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cp += wp->cnt;
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nb += wp->cnt;
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}
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if (mode & MODE_ALIAS) {
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PacketAliasIn((struct ip *)tunbuff);
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nb = ntohs(((struct ip *)tunbuff)->ip_len);
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}
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if ( PacketCheck(tunbuff, nb, FL_IN ) < 0) {
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pfree(bp);
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return;
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}
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ipInOctets += nb;
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/*
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* Pass it to tunnel device
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*/
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nw = write(tun_out, tunbuff, nb);
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if (nw != nb)
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fprintf(stderr, "wrote %d, got %d\r\n", nb, nw);
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pfree(bp);
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RestartIdleTimer();
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}
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static struct mqueue IpOutputQueues[PRI_FAST+1];
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void
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IpEnqueue(pri, ptr, count)
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int pri;
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char *ptr;
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int count;
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{
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struct mbuf *bp;
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bp = mballoc(count, MB_IPQ);
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bcopy(ptr, MBUF_CTOP(bp), count);
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Enqueue(&IpOutputQueues[pri], bp);
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}
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int
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IsIpEnqueued()
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{
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struct mqueue *queue;
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int exist = FALSE;
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for (queue = &IpOutputQueues[PRI_FAST]; queue >= IpOutputQueues; queue--) {
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if ( queue->qlen > 0 ) {
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exist = TRUE;
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break;
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}
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}
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return( exist );
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}
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void
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IpStartOutput()
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{
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struct mqueue *queue;
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struct mbuf *bp;
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int cnt;
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if (IpcpFsm.state != ST_OPENED)
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return;
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for (queue = &IpOutputQueues[PRI_FAST]; queue >= IpOutputQueues; queue--) {
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if (queue->top) {
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bp = Dequeue(queue);
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if (bp) {
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cnt = plength(bp);
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SendPppFrame(bp);
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RestartIdleTimer();
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ipOutOctets += cnt;
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break;
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}
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}
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}
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}
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