538 lines
14 KiB
C
538 lines
14 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 1.37 1998/01/11 17:53:18 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 <sys/param.h>
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#include <sys/time.h>
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#include <sys/socket.h>
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#include <net/if.h>
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#include <net/if_tun.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_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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#ifndef NOALIAS
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#include <alias.h>
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#endif
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#include <errno.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <termios.h>
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#include <unistd.h>
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#include "command.h"
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#include "mbuf.h"
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#include "log.h"
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#include "defs.h"
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#include "timer.h"
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#include "fsm.h"
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#include "hdlc.h"
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#include "loadalias.h"
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#include "vars.h"
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#include "filter.h"
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#include "os.h"
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#include "ipcp.h"
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#include "vjcomp.h"
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#include "lcp.h"
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#include "modem.h"
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#include "tun.h"
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#include "ip.h"
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static struct pppTimer IdleTimer;
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static void
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IdleTimeout(void *v)
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{
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LogPrintf(LogPHASE, "Idle timer expired.\n");
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reconnect(RECON_FALSE);
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LcpClose();
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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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static time_t IdleStarted;
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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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time(&IdleStarted);
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IdleTimer.arg = (void *)&IdleStarted;
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StartTimer(&IdleTimer);
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}
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}
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void
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UpdateIdleTimer()
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{
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if (OsLinkIsUp())
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StartIdleTimer();
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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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int
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RemainingIdleTime()
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{
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if (VarIdleTimeout == 0 || IdleTimer.state != TIMER_RUNNING ||
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IdleTimer.arg == NULL)
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return -1;
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return VarIdleTimeout - (time(NULL) - *(time_t *)IdleTimer.arg);
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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(void)
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{
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if (!(mode & (MODE_DEDICATED | MODE_DDIAL)) && ipKeepAlive) {
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time((time_t *)IdleTimer.arg);
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StartTimer(&IdleTimer);
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}
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}
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static const 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 const char *TcpFlags[] = { "FIN", "SYN", "RST", "PSH", "ACK", "URG" };
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static const 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(int op, u_short pport, u_short 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(struct ip * pip, 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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LogPrintf(LogDEBUG, "rule = %d\n", n);
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if ((pip->ip_src.s_addr & fp->smask.s_addr) ==
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(fp->saddr.s_addr & fp->smask.s_addr) &&
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(pip->ip_dst.s_addr & fp->dmask.s_addr) ==
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(fp->daddr.s_addr & fp->dmask.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;
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ih = (struct icmp *) ptop;
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sport = ih->icmp_type;
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estab = 1;
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break;
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case IPPROTO_UDP:
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cproto = P_UDP;
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uh = (struct udphdr *) ptop;
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sport = ntohs(uh->uh_sport);
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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;
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th = (struct tcphdr *) ptop;
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sport = ntohs(th->th_sport);
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dport = ntohs(th->th_dport);
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estab = (th->th_flags & TH_ACK);
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if (estab == 0)
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LogPrintf(LogDEBUG, "flag = %02x, sport = %d, dport = %d\n",
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th->th_flags, sport, dport);
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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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LogPrintf(LogDEBUG, "dir = %d, proto = %d, srcop = %d,"
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" dstop = %d, estab = %d\n", direction, cproto,
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fp->opt.srcop, fp->opt.dstop, estab);
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}
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LogPrintf(LogDEBUG, "check0: rule = %d, proto = %d, sport = %d,"
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" dport = %d\n", n, cproto, sport, dport);
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LogPrintf(LogDEBUG, "check0: action = %d\n", fp->action);
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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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LogPrintf(LogDEBUG, "check1: action = %d\n", fp->action);
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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(struct ip * pip, 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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memcpy(MBUF_CTOP(bp), ptr, cnt);
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SendPppFrame(bp);
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RestartIdleTimer();
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IpcpAddOutOctets(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(char *cp, int nb, 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 pri = PRI_NORMAL;
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int logit, loglen;
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static char logbuf[200];
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logit = LogIsKept(LogTCPIP) && direction != FL_DIAL;
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loglen = 0;
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pip = (struct ip *) cp;
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if (logit && loglen < sizeof logbuf) {
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snprintf(logbuf + loglen, sizeof logbuf - loglen, "%s ",
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Direction[direction]);
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loglen += strlen(logbuf + loglen);
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}
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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 && loglen < sizeof logbuf) {
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icmph = (struct icmp *) ptop;
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snprintf(logbuf + loglen, sizeof logbuf - loglen,
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"ICMP: %s:%d ---> ", inet_ntoa(pip->ip_src), icmph->icmp_type);
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loglen += strlen(logbuf + loglen);
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snprintf(logbuf + loglen, sizeof logbuf - loglen,
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"%s:%d", inet_ntoa(pip->ip_dst), icmph->icmp_type);
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loglen += strlen(logbuf + loglen);
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}
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break;
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case IPPROTO_UDP:
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if (logit && loglen < sizeof logbuf) {
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uh = (struct udphdr *) ptop;
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snprintf(logbuf + loglen, sizeof logbuf - loglen,
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"UDP: %s:%d ---> ", inet_ntoa(pip->ip_src), ntohs(uh->uh_sport));
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loglen += strlen(logbuf + loglen);
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snprintf(logbuf + loglen, sizeof logbuf - loglen,
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"%s:%d", inet_ntoa(pip->ip_dst), ntohs(uh->uh_dport));
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loglen += strlen(logbuf + loglen);
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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 && loglen < sizeof logbuf) {
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len = ntohs(pip->ip_len) - (pip->ip_hl << 2) - (th->th_off << 2);
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snprintf(logbuf + loglen, sizeof logbuf - loglen,
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"TCP: %s:%d ---> ", inet_ntoa(pip->ip_src), ntohs(th->th_sport));
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loglen += strlen(logbuf + loglen);
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snprintf(logbuf + loglen, sizeof logbuf - loglen,
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"%s:%d", inet_ntoa(pip->ip_dst), ntohs(th->th_dport));
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loglen += strlen(logbuf + loglen);
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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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snprintf(logbuf + loglen, sizeof logbuf - loglen, " %s", TcpFlags[n]);
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loglen += strlen(logbuf + loglen);
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}
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n++;
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}
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snprintf(logbuf + loglen, sizeof logbuf - loglen,
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" seq:%x ack:%x (%d/%d)",
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ntohl(th->th_seq), ntohl(th->th_ack), len, nb);
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loglen += strlen(logbuf + loglen);
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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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snprintf(logbuf + loglen, sizeof logbuf - loglen,
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" MSS = %d", ntohs(sp[1]));
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loglen += strlen(logbuf + loglen);
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}
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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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if (logit)
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LogPrintf(LogTCPIP, "%s - BLOCKED\n", logbuf);
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if (direction == 0)
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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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if (logit)
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LogPrintf(LogTCPIP, "%s - NO KEEPALIVE\n", logbuf);
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ipKeepAlive = 0;
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} else {
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if (logit)
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LogPrintf(LogTCPIP, "%s\n", logbuf);
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ipKeepAlive = 1;
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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(struct mbuf * bp)
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{ /* IN: Pointer to IP pakcet */
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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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struct tun_data tun;
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tun_fill_header(tun, AF_INET);
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cp = tun.data;
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nb = 0;
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for (wp = bp; wp; wp = wp->next) { /* Copy to contiguous region */
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if (sizeof tun.data - (cp - tun.data) < wp->cnt) {
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LogPrintf(LogERROR, "IpInput: Packet too large (%d) - dropped\n",
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plength(bp));
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pfree(bp);
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return;
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}
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memcpy(cp, MBUF_CTOP(wp), wp->cnt);
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cp += wp->cnt;
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nb += wp->cnt;
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}
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#ifndef NOALIAS
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if (mode & MODE_ALIAS) {
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struct tun_data *frag;
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int iresult;
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char *fptr;
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iresult = VarPacketAliasIn(tun.data, sizeof tun.data);
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nb = ntohs(((struct ip *) tun.data)->ip_len);
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if (nb > MAX_MRU) {
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LogPrintf(LogERROR, "IpInput: Problem with IP header length\n");
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pfree(bp);
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return;
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}
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if (iresult == PKT_ALIAS_OK
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|| iresult == PKT_ALIAS_FOUND_HEADER_FRAGMENT) {
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if (PacketCheck(tun.data, nb, FL_IN) < 0) {
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pfree(bp);
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return;
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}
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IpcpAddInOctets(nb);
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nb = ntohs(((struct ip *) tun.data)->ip_len);
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nb += sizeof tun - sizeof tun.data;
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nw = write(tun_out, &tun, nb);
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if (nw != nb)
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if (nw == -1)
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LogPrintf(LogERROR, "IpInput: wrote %d, got %s\n", nb,
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strerror(errno));
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else
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LogPrintf(LogERROR, "IpInput: wrote %d, got %d\n", nb, nw);
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if (iresult == PKT_ALIAS_FOUND_HEADER_FRAGMENT) {
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while ((fptr = VarPacketAliasGetFragment(tun.data)) != NULL) {
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VarPacketAliasFragmentIn(tun.data, fptr);
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nb = ntohs(((struct ip *) fptr)->ip_len);
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frag = (struct tun_data *)
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((char *)fptr - sizeof tun + sizeof tun.data);
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nb += sizeof tun - sizeof tun.data;
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nw = write(tun_out, frag, nb);
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if (nw != nb)
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if (nw == -1)
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LogPrintf(LogERROR, "IpInput: wrote %d, got %s\n", nb,
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strerror(errno));
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else
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LogPrintf(LogERROR, "IpInput: wrote %d, got %d\n", nb, nw);
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free(frag);
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}
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}
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} else if (iresult == PKT_ALIAS_UNRESOLVED_FRAGMENT) {
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nb = ntohs(((struct ip *) tun.data)->ip_len);
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nb += sizeof tun - sizeof tun.data;
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frag = (struct tun_data *)malloc(nb);
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if (frag == NULL)
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LogPrintf(LogALERT, "IpInput: Cannot allocate memory for fragment\n");
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else {
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tun_fill_header(*frag, AF_INET);
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memcpy(frag->data, tun.data, nb - sizeof tun + sizeof tun.data);
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VarPacketAliasSaveFragment(frag->data);
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}
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}
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} else
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#endif /* #ifndef NOALIAS */
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{ /* no aliasing */
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if (PacketCheck(tun.data, nb, FL_IN) < 0) {
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pfree(bp);
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return;
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}
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IpcpAddInOctets(nb);
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nb += sizeof tun - sizeof tun.data;
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nw = write(tun_out, &tun, nb);
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if (nw != nb)
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if (nw == -1)
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LogPrintf(LogERROR, "IpInput: wrote %d, got %s\n", nb, strerror(errno));
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else
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LogPrintf(LogERROR, "IpInput: wrote %d, got %d\n", nb, nw);
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}
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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(int pri, char *ptr, int count)
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{
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|
struct mbuf *bp;
|
|
|
|
bp = mballoc(count, MB_IPQ);
|
|
memcpy(MBUF_CTOP(bp), ptr, count);
|
|
Enqueue(&IpOutputQueues[pri], bp);
|
|
}
|
|
|
|
#if 0
|
|
int
|
|
IsIpEnqueued()
|
|
{
|
|
struct mqueue *queue;
|
|
int exist = 0;
|
|
|
|
for (queue = &IpOutputQueues[PRI_FAST]; queue >= IpOutputQueues; queue--) {
|
|
if (queue->qlen > 0) {
|
|
exist = 1;
|
|
break;
|
|
}
|
|
}
|
|
return (exist);
|
|
}
|
|
#endif
|
|
|
|
void
|
|
IpStartOutput()
|
|
{
|
|
struct mqueue *queue;
|
|
struct mbuf *bp;
|
|
int cnt;
|
|
|
|
if (IpcpFsm.state != ST_OPENED)
|
|
return;
|
|
for (queue = &IpOutputQueues[PRI_FAST]; queue >= IpOutputQueues; queue--) {
|
|
if (queue->top) {
|
|
bp = Dequeue(queue);
|
|
if (bp) {
|
|
cnt = plength(bp);
|
|
SendPppFrame(bp);
|
|
RestartIdleTimer();
|
|
IpcpAddOutOctets(cnt);
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|