500 lines
11 KiB
C
500 lines
11 KiB
C
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/*
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* PPP Filter command 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: filter.c,v 1.21 1997/12/24 09:28:57 brian Exp $
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*
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* TODO: Shoud send ICMP error message when we discard packets.
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*/
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#include <sys/param.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#include <netdb.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <strings.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 "loadalias.h"
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#include "defs.h"
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#include "vars.h"
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#include "ipcp.h"
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#include "filter.h"
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struct filterent ifilters[MAXFILTERS]; /* incoming packet filter */
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struct filterent ofilters[MAXFILTERS]; /* outgoing packet filter */
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struct filterent dfilters[MAXFILTERS]; /* dial-out packet filter */
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struct filterent afilters[MAXFILTERS]; /* keep-alive packet filter */
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static struct filterent filterdata;
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static u_long netmasks[33] = {
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0x00000000,
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0x80000000, 0xC0000000, 0xE0000000, 0xF0000000,
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0xF8000000, 0xFC000000, 0xFE000000, 0xFF000000,
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0xFF800000, 0xFFC00000, 0xFFE00000, 0xFFF00000,
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0xFFF80000, 0xFFFC0000, 0xFFFE0000, 0xFFFF0000,
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0xFFFF8000, 0xFFFFC000, 0xFFFFE000, 0xFFFFF000,
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0xFFFFF800, 0xFFFFFC00, 0xFFFFFE00, 0xFFFFFF00,
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0xFFFFFF80, 0xFFFFFFC0, 0xFFFFFFE0, 0xFFFFFFF0,
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0xFFFFFFF8, 0xFFFFFFFC, 0xFFFFFFFE, 0xFFFFFFFF,
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};
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int
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ParseAddr(int argc,
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char const *const *argv,
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struct in_addr * paddr,
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struct in_addr * pmask,
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int *pwidth)
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{
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int bits, len;
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char *wp;
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const char *cp;
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if (argc < 1) {
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LogPrintf(LogWARN, "ParseAddr: address/mask is expected.\n");
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return (0);
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}
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if (pmask)
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pmask->s_addr = 0xffffffff; /* Assume 255.255.255.255 as default */
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cp = pmask || pwidth ? strchr(*argv, '/') : NULL;
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len = cp ? cp - *argv : strlen(*argv);
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if (strncasecmp(*argv, "HISADDR", len) == 0)
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*paddr = IpcpInfo.his_ipaddr;
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else if (strncasecmp(*argv, "MYADDR", len) == 0)
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*paddr = IpcpInfo.want_ipaddr;
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else if (len > 15)
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LogPrintf(LogWARN, "ParseAddr: %s: Bad address\n", *argv);
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else {
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char s[16];
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strncpy(s, *argv, len);
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s[len] = '\0';
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if (inet_aton(s, paddr) == 0) {
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LogPrintf(LogWARN, "ParseAddr: %s: Bad address\n", s);
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return (0);
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}
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}
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if (cp && *++cp) {
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bits = strtol(cp, &wp, 0);
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if (cp == wp || bits < 0 || bits > 32) {
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LogPrintf(LogWARN, "ParseAddr: bad mask width.\n");
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return (0);
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}
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} else {
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/* if width is not given, assume whole 32 bits are meaningfull */
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bits = 32;
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}
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if (pwidth)
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*pwidth = bits;
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if (pmask)
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pmask->s_addr = htonl(netmasks[bits]);
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return (1);
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}
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static int
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ParseProto(int argc, char const *const *argv)
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{
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int proto;
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if (argc < 1)
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return (P_NONE);
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if (!strcmp(*argv, "tcp"))
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proto = P_TCP;
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else if (!strcmp(*argv, "udp"))
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proto = P_UDP;
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else if (!strcmp(*argv, "icmp"))
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proto = P_ICMP;
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else
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proto = P_NONE;
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return (proto);
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}
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static int
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ParsePort(const char *service, int proto)
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{
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const char *protocol_name;
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char *cp;
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struct servent *servent;
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int port;
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switch (proto) {
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case P_UDP:
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protocol_name = "udp";
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break;
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case P_TCP:
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protocol_name = "tcp";
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break;
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default:
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protocol_name = 0;
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}
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servent = getservbyname(service, protocol_name);
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if (servent != 0)
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return (ntohs(servent->s_port));
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port = strtol(service, &cp, 0);
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if (cp == service) {
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LogPrintf(LogWARN, "ParsePort: %s is not a port name or number.\n",
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service);
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return (0);
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}
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return (port);
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}
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/*
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* ICMP Syntax: src eq icmp_message_type
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*/
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static int
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ParseIcmp(int argc, char const *const *argv)
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{
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int type;
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char *cp;
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switch (argc) {
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case 0:
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/* permit/deny all ICMP types */
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filterdata.opt.srcop = OP_NONE;
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break;
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default:
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LogPrintf(LogWARN, "ParseIcmp: bad icmp syntax.\n");
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return (0);
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case 3:
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if (!strcmp(*argv, "src") && !strcmp(argv[1], "eq")) {
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type = strtol(argv[2], &cp, 0);
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if (cp == argv[2]) {
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LogPrintf(LogWARN, "ParseIcmp: type is expected.\n");
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return (0);
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}
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filterdata.opt.srcop = OP_EQ;
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filterdata.opt.srcport = type;
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}
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break;
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}
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return (1);
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}
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static int
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ParseOp(const char *cp)
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{
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int op = OP_NONE;
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if (!strcmp(cp, "eq"))
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op = OP_EQ;
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else if (!strcmp(cp, "gt"))
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op = OP_GT;
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else if (!strcmp(cp, "lt"))
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op = OP_LT;
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return (op);
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}
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/*
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* UDP Syntax: [src op port] [dst op port]
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*/
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static int
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ParseUdpOrTcp(int argc, char const *const *argv, int proto)
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{
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filterdata.opt.srcop = filterdata.opt.dstop = OP_NONE;
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filterdata.opt.estab = 0;
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if (argc == 0) {
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/* permit/deny all tcp traffic */
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return (1);
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}
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if (argc >= 3 && !strcmp(*argv, "src")) {
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filterdata.opt.srcop = ParseOp(argv[1]);
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if (filterdata.opt.srcop == OP_NONE) {
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LogPrintf(LogWARN, "ParseUdpOrTcp: bad operation\n");
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return (0);
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}
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filterdata.opt.srcport = ParsePort(argv[2], proto);
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if (filterdata.opt.srcport == 0)
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return (0);
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argc -= 3;
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argv += 3;
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if (argc == 0)
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return (1);
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}
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if (argc >= 3 && !strcmp(argv[0], "dst")) {
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filterdata.opt.dstop = ParseOp(argv[1]);
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if (filterdata.opt.dstop == OP_NONE) {
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LogPrintf(LogWARN, "ParseUdpOrTcp: bad operation\n");
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return (0);
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}
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filterdata.opt.dstport = ParsePort(argv[2], proto);
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if (filterdata.opt.dstport == 0)
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return (0);
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argc -= 3;
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argv += 3;
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if (argc == 0)
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return (1);
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}
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if (argc == 1 && proto == P_TCP) {
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if (!strcmp(*argv, "estab")) {
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filterdata.opt.estab = 1;
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return (1);
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}
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LogPrintf(LogWARN, "ParseUdpOrTcp: estab is expected: %s\n", *argv);
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return (0);
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}
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if (argc > 0)
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LogPrintf(LogWARN, "ParseUdpOrTcp: bad src/dst port syntax: %s\n", *argv);
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return (0);
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}
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static const char *opname[] = {"none", "eq", "gt", NULL, "lt"};
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static int
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Parse(int argc, char const *const *argv, struct filterent * ofp)
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{
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int action, proto;
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int val;
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char *wp;
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struct filterent *fp = &filterdata;
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val = strtol(*argv, &wp, 0);
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if (*argv == wp || val > MAXFILTERS) {
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LogPrintf(LogWARN, "Parse: invalid filter number.\n");
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return (0);
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}
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if (val < 0) {
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for (val = 0; val < MAXFILTERS; val++) {
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ofp->action = A_NONE;
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ofp++;
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}
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LogPrintf(LogWARN, "Parse: filter cleared.\n");
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return (1);
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}
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ofp += val;
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if (--argc == 0) {
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LogPrintf(LogWARN, "Parse: missing action.\n");
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return (0);
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}
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argv++;
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proto = P_NONE;
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memset(&filterdata, '\0', sizeof filterdata);
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if (!strcmp(*argv, "permit")) {
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action = A_PERMIT;
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} else if (!strcmp(*argv, "deny")) {
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action = A_DENY;
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} else if (!strcmp(*argv, "clear")) {
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ofp->action = A_NONE;
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return (1);
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} else {
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LogPrintf(LogWARN, "Parse: bad action: %s\n", *argv);
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return (0);
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}
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fp->action = action;
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argc--;
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argv++;
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if (fp->action == A_DENY) {
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if (!strcmp(*argv, "host")) {
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fp->action |= A_UHOST;
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argc--;
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argv++;
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} else if (!strcmp(*argv, "port")) {
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fp->action |= A_UPORT;
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argc--;
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argv++;
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}
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}
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proto = ParseProto(argc, argv);
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if (proto == P_NONE) {
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if (ParseAddr(argc, argv, &fp->saddr, &fp->smask, &fp->swidth)) {
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argc--;
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argv++;
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proto = ParseProto(argc, argv);
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if (proto == P_NONE) {
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if (ParseAddr(argc, argv, &fp->daddr, &fp->dmask, &fp->dwidth)) {
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argc--;
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argv++;
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}
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proto = ParseProto(argc, argv);
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if (proto != P_NONE) {
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argc--;
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argv++;
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}
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} else {
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argc--;
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argv++;
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}
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} else {
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LogPrintf(LogWARN, "Parse: Address/protocol expected.\n");
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return (0);
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}
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} else {
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argc--;
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argv++;
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}
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val = 1;
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fp->proto = proto;
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switch (proto) {
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case P_TCP:
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val = ParseUdpOrTcp(argc, argv, P_TCP);
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break;
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case P_UDP:
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val = ParseUdpOrTcp(argc, argv, P_UDP);
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break;
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case P_ICMP:
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val = ParseIcmp(argc, argv);
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break;
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}
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LogPrintf(LogDEBUG, "Parse: Src: %s\n", inet_ntoa(fp->saddr));
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LogPrintf(LogDEBUG, "Parse: Src mask: %s\n", inet_ntoa(fp->smask));
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LogPrintf(LogDEBUG, "Parse: Dst: %s\n", inet_ntoa(fp->daddr));
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LogPrintf(LogDEBUG, "Parse: Dst mask: %s\n", inet_ntoa(fp->dmask));
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LogPrintf(LogDEBUG, "Parse: Proto = %d\n", proto);
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LogPrintf(LogDEBUG, "Parse: src: %s (%d)\n", opname[fp->opt.srcop],
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fp->opt.srcport);
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|
|
LogPrintf(LogDEBUG, "Parse: dst: %s (%d)\n", opname[fp->opt.dstop],
|
||
|
|
fp->opt.dstport);
|
||
|
|
LogPrintf(LogDEBUG, "Parse: estab: %d\n", fp->opt.estab);
|
||
|
|
|
||
|
|
if (val)
|
||
|
|
*ofp = *fp;
|
||
|
|
return (val);
|
||
|
|
}
|
||
|
|
|
||
|
|
int
|
||
|
|
SetIfilter(struct cmdargs const *arg)
|
||
|
|
{
|
||
|
|
if (arg->argc > 0) {
|
||
|
|
Parse(arg->argc, arg->argv, ifilters);
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
|
||
|
|
int
|
||
|
|
SetOfilter(struct cmdargs const *arg)
|
||
|
|
{
|
||
|
|
if (arg->argc > 0) {
|
||
|
|
(void) Parse(arg->argc, arg->argv, ofilters);
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
|
||
|
|
int
|
||
|
|
SetDfilter(struct cmdargs const *arg)
|
||
|
|
{
|
||
|
|
if (arg->argc > 0) {
|
||
|
|
(void) Parse(arg->argc, arg->argv, dfilters);
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
|
||
|
|
int
|
||
|
|
SetAfilter(struct cmdargs const *arg)
|
||
|
|
{
|
||
|
|
if (arg->argc > 0) {
|
||
|
|
(void) Parse(arg->argc, arg->argv, afilters);
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
return -1;
|
||
|
|
}
|
||
|
|
|
||
|
|
static const char *protoname[] = { "none", "tcp", "udp", "icmp" };
|
||
|
|
static const char *actname[] = { "none ", "permit ", "deny " };
|
||
|
|
|
||
|
|
static void
|
||
|
|
ShowFilter(struct filterent * fp)
|
||
|
|
{
|
||
|
|
int n;
|
||
|
|
|
||
|
|
if (!VarTerm)
|
||
|
|
return;
|
||
|
|
|
||
|
|
for (n = 0; n < MAXFILTERS; n++, fp++) {
|
||
|
|
if (fp->action != A_NONE) {
|
||
|
|
fprintf(VarTerm, "%2d %s", n, actname[fp->action & (A_PERMIT|A_DENY)]);
|
||
|
|
if (fp->action & A_UHOST)
|
||
|
|
fprintf(VarTerm, "host ");
|
||
|
|
else if (fp->action & A_UPORT)
|
||
|
|
fprintf(VarTerm, "port ");
|
||
|
|
else
|
||
|
|
fprintf(VarTerm, " ");
|
||
|
|
fprintf(VarTerm, "%s/%d ", inet_ntoa(fp->saddr), fp->swidth);
|
||
|
|
fprintf(VarTerm, "%s/%d ", inet_ntoa(fp->daddr), fp->dwidth);
|
||
|
|
if (fp->proto) {
|
||
|
|
fprintf(VarTerm, "%s", protoname[fp->proto]);
|
||
|
|
|
||
|
|
if (fp->opt.srcop)
|
||
|
|
fprintf(VarTerm, " src %s %d", opname[fp->opt.srcop],
|
||
|
|
fp->opt.srcport);
|
||
|
|
if (fp->opt.dstop)
|
||
|
|
fprintf(VarTerm, " dst %s %d", opname[fp->opt.dstop],
|
||
|
|
fp->opt.dstport);
|
||
|
|
if (fp->opt.estab)
|
||
|
|
fprintf(VarTerm, " estab");
|
||
|
|
|
||
|
|
}
|
||
|
|
fprintf(VarTerm, "\n");
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
int
|
||
|
|
ShowIfilter(struct cmdargs const *arg)
|
||
|
|
{
|
||
|
|
ShowFilter(ifilters);
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
int
|
||
|
|
ShowOfilter(struct cmdargs const *arg)
|
||
|
|
{
|
||
|
|
ShowFilter(ofilters);
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
int
|
||
|
|
ShowDfilter(struct cmdargs const *arg)
|
||
|
|
{
|
||
|
|
ShowFilter(dfilters);
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
int
|
||
|
|
ShowAfilter(struct cmdargs const *arg)
|
||
|
|
{
|
||
|
|
ShowFilter(afilters);
|
||
|
|
return 0;
|
||
|
|
}
|