filter.c revision 48142 
1/*
2 *		PPP Filter command Interface
3 *
4 *	    Written by Toshiharu OHNO (tony-o@iij.ad.jp)
5 *
6 *   Copyright (C) 1993, Internet Initiative Japan, Inc. All rights reserverd.
7 *
8 * Redistribution and use in source and binary forms are permitted
9 * provided that the above copyright notice and this paragraph are
10 * duplicated in all such forms and that any documentation,
11 * advertising materials, and other materials related to such
12 * distribution and use acknowledge that the software was developed
13 * by the Internet Initiative Japan.  The name of the
14 * IIJ may not be used to endorse or promote products derived
15 * from this software without specific prior written permission.
16 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
18 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
19 *
20 * $Id: filter.c,v 1.29 1999/05/31 23:57:36 brian Exp $
21 *
22 *	TODO: Shoud send ICMP error message when we discard packets.
23 */
24
25#include <sys/param.h>
26#include <netinet/in.h>
27#include <arpa/inet.h>
28#include <netdb.h>
29#include <netinet/in_systm.h>
30#include <netinet/ip.h>
31#include <sys/un.h>
32
33#include <stdio.h>
34#include <stdlib.h>
35#include <strings.h>
36#include <termios.h>
37
38#include "layer.h"
39#include "defs.h"
40#include "command.h"
41#include "mbuf.h"
42#include "log.h"
43#include "iplist.h"
44#include "timer.h"
45#include "throughput.h"
46#include "lqr.h"
47#include "hdlc.h"
48#include "fsm.h"
49#include "lcp.h"
50#include "ccp.h"
51#include "link.h"
52#include "slcompress.h"
53#include "ipcp.h"
54#include "filter.h"
55#include "descriptor.h"
56#include "prompt.h"
57#include "mp.h"
58#ifndef NORADIUS
59#include "radius.h"
60#endif
61#include "bundle.h"
62
63static int filter_Nam2Proto(int, char const *const *);
64static int filter_Nam2Op(const char *);
65
66static const u_int32_t netmasks[33] = {
67  0x00000000,
68  0x80000000, 0xC0000000, 0xE0000000, 0xF0000000,
69  0xF8000000, 0xFC000000, 0xFE000000, 0xFF000000,
70  0xFF800000, 0xFFC00000, 0xFFE00000, 0xFFF00000,
71  0xFFF80000, 0xFFFC0000, 0xFFFE0000, 0xFFFF0000,
72  0xFFFF8000, 0xFFFFC000, 0xFFFFE000, 0xFFFFF000,
73  0xFFFFF800, 0xFFFFFC00, 0xFFFFFE00, 0xFFFFFF00,
74  0xFFFFFF80, 0xFFFFFFC0, 0xFFFFFFE0, 0xFFFFFFF0,
75  0xFFFFFFF8, 0xFFFFFFFC, 0xFFFFFFFE, 0xFFFFFFFF,
76};
77
78struct in_addr
79bits2mask(int bits)
80{
81  struct in_addr result;
82
83  result.s_addr = htonl(netmasks[bits]);
84  return result;
85}
86
87int
88ParseAddr(struct ipcp *ipcp, const char *data,
89	  struct in_addr *paddr, struct in_addr *pmask, int *pwidth)
90{
91  int bits, len;
92  char *wp;
93  const char *cp;
94
95  if (pmask)
96    pmask->s_addr = INADDR_BROADCAST;	/* Assume 255.255.255.255 as default */
97
98  cp = pmask || pwidth ? strchr(data, '/') : NULL;
99  len = cp ? cp - data : strlen(data);
100
101  if (ipcp && strncasecmp(data, "HISADDR", len) == 0)
102    *paddr = ipcp->peer_ip;
103  else if (ipcp && strncasecmp(data, "MYADDR", len) == 0)
104    *paddr = ipcp->my_ip;
105  else if (len > 15)
106    log_Printf(LogWARN, "ParseAddr: %s: Bad address\n", data);
107  else {
108    char s[16];
109    strncpy(s, data, len);
110    s[len] = '\0';
111    if (inet_aton(s, paddr) == 0) {
112      log_Printf(LogWARN, "ParseAddr: %s: Bad address\n", s);
113      return (0);
114    }
115  }
116  if (cp && *++cp) {
117    bits = strtol(cp, &wp, 0);
118    if (cp == wp || bits < 0 || bits > 32) {
119      log_Printf(LogWARN, "ParseAddr: bad mask width.\n");
120      return (0);
121    }
122  } else if (paddr->s_addr == INADDR_ANY)
123    /* An IP of 0.0.0.0 without a width is anything */
124    bits = 0;
125  else
126    /* If a valid IP is given without a width, assume 32 bits */
127    bits = 32;
128
129  if (pwidth)
130    *pwidth = bits;
131
132  if (pmask) {
133    if (paddr->s_addr == INADDR_ANY)
134      pmask->s_addr = INADDR_ANY;
135    else
136      *pmask = bits2mask(bits);
137  }
138
139  return (1);
140}
141
142static int
143ParsePort(const char *service, int proto)
144{
145  const char *protocol_name;
146  char *cp;
147  struct servent *servent;
148  int port;
149
150  switch (proto) {
151  case P_UDP:
152    protocol_name = "udp";
153    break;
154  case P_TCP:
155    protocol_name = "tcp";
156    break;
157  default:
158    protocol_name = 0;
159  }
160
161  servent = getservbyname(service, protocol_name);
162  if (servent != 0)
163    return (ntohs(servent->s_port));
164
165  port = strtol(service, &cp, 0);
166  if (cp == service) {
167    log_Printf(LogWARN, "ParsePort: %s is not a port name or number.\n",
168	      service);
169    return (0);
170  }
171  return (port);
172}
173
174/*
175 *	ICMP Syntax:	src eq icmp_message_type
176 */
177static int
178ParseIcmp(int argc, char const *const *argv, struct filterent *tgt)
179{
180  int type;
181  char *cp;
182
183  switch (argc) {
184  case 0:
185    /* permit/deny all ICMP types */
186    tgt->opt.srcop = OP_NONE;
187    break;
188
189  case 3:
190    if (!strcmp(*argv, "src") && !strcmp(argv[1], "eq")) {
191      type = strtol(argv[2], &cp, 0);
192      if (cp == argv[2]) {
193	log_Printf(LogWARN, "ParseIcmp: type is expected.\n");
194	return (0);
195      }
196      tgt->opt.srcop = OP_EQ;
197      tgt->opt.srcport = type;
198    }
199    break;
200
201  default:
202    log_Printf(LogWARN, "ParseIcmp: bad icmp syntax.\n");
203    return (0);
204  }
205  return (1);
206}
207
208/*
209 *	UDP Syntax: [src op port] [dst op port]
210 */
211static int
212ParseUdpOrTcp(int argc, char const *const *argv, int proto,
213              struct filterent *tgt)
214{
215  tgt->opt.srcop = tgt->opt.dstop = OP_NONE;
216  tgt->opt.estab = tgt->opt.syn = tgt->opt.finrst = 0;
217
218  if (argc >= 3 && !strcmp(*argv, "src")) {
219    tgt->opt.srcop = filter_Nam2Op(argv[1]);
220    if (tgt->opt.srcop == OP_NONE) {
221      log_Printf(LogWARN, "ParseUdpOrTcp: bad operation\n");
222      return (0);
223    }
224    tgt->opt.srcport = ParsePort(argv[2], proto);
225    if (tgt->opt.srcport == 0)
226      return (0);
227    argc -= 3;
228    argv += 3;
229  }
230
231  if (argc >= 3 && !strcmp(argv[0], "dst")) {
232    tgt->opt.dstop = filter_Nam2Op(argv[1]);
233    if (tgt->opt.dstop == OP_NONE) {
234      log_Printf(LogWARN, "ParseUdpOrTcp: bad operation\n");
235      return (0);
236    }
237    tgt->opt.dstport = ParsePort(argv[2], proto);
238    if (tgt->opt.dstport == 0)
239      return (0);
240    argc -= 3;
241    argv += 3;
242  }
243
244  if (proto == P_TCP) {
245    for (; argc > 0; argc--, argv++)
246      if (!strcmp(*argv, "estab"))
247        tgt->opt.estab = 1;
248      else if (!strcmp(*argv, "syn"))
249        tgt->opt.syn = 1;
250      else if (!strcmp(*argv, "finrst"))
251        tgt->opt.finrst = 1;
252      else
253        break;
254  }
255
256  if (argc > 0) {
257    log_Printf(LogWARN, "ParseUdpOrTcp: bad src/dst port syntax: %s\n", *argv);
258    return 0;
259  }
260
261  return 1;
262}
263
264static int ParseIgmp(int argc, char const * const *argv, struct filterent *tgt) {
265  /* Filter currently is a catch-all. Requests are either permitted or
266     dropped. */
267  if (argc != 0) {
268    log_Printf(LogWARN, "ParseIgmp: Too many parameters\n");
269    return 0;
270  } else
271    tgt->opt.srcop = OP_NONE;
272
273  return 1;
274}
275
276static unsigned
277addrtype(const char *addr)
278{
279  if (!strncasecmp(addr, "MYADDR", 6) && (addr[6] == '\0' || addr[6] == '/'))
280    return T_MYADDR;
281  if (!strncasecmp(addr, "HISADDR", 7) && (addr[7] == '\0' || addr[7] == '/'))
282    return T_HISADDR;
283
284  return T_ADDR;
285}
286
287static const char *
288addrstr(struct in_addr addr, unsigned type)
289{
290  switch (type) {
291    case T_MYADDR:
292      return "MYADDR";
293    case T_HISADDR:
294      return "HISADDR";
295  }
296  return inet_ntoa(addr);
297}
298
299static int
300Parse(struct ipcp *ipcp, int argc, char const *const *argv,
301      struct filterent *ofp)
302{
303  int action, proto;
304  int val;
305  char *wp;
306  struct filterent filterdata;
307
308  val = strtol(*argv, &wp, 0);
309  if (*argv == wp || val > MAXFILTERS) {
310    log_Printf(LogWARN, "Parse: invalid filter number.\n");
311    return (0);
312  }
313  if (val < 0) {
314    for (val = 0; val < MAXFILTERS; val++) {
315      ofp->action = A_NONE;
316      ofp++;
317    }
318    log_Printf(LogWARN, "Parse: filter cleared.\n");
319    return (1);
320  }
321  ofp += val;
322
323  if (--argc == 0) {
324    log_Printf(LogWARN, "Parse: missing action.\n");
325    return (0);
326  }
327  argv++;
328
329  proto = P_NONE;
330  memset(&filterdata, '\0', sizeof filterdata);
331
332  if (!strcmp(*argv, "permit")) {
333    action = A_PERMIT;
334  } else if (!strcmp(*argv, "deny")) {
335    action = A_DENY;
336  } else if (!strcmp(*argv, "clear")) {
337    ofp->action = A_NONE;
338    return (1);
339  } else {
340    log_Printf(LogWARN, "Parse: bad action: %s\n", *argv);
341    return (0);
342  }
343  filterdata.action = action;
344
345  argc--;
346  argv++;
347
348  if (argc && filterdata.action == A_DENY) {
349    if (!strcmp(*argv, "host")) {
350      filterdata.action |= A_UHOST;
351      argc--;
352      argv++;
353    } else if (!strcmp(*argv, "port")) {
354      filterdata.action |= A_UPORT;
355      argc--;
356      argv++;
357    }
358  }
359
360  proto = filter_Nam2Proto(argc, argv);
361  if (proto == P_NONE) {
362    if (!argc)
363      log_Printf(LogWARN, "Parse: address/mask is expected.\n");
364    else if (ParseAddr(ipcp, *argv, &filterdata.src.ipaddr,
365                       &filterdata.src.mask, &filterdata.src.width)) {
366      filterdata.srctype = addrtype(*argv);
367      argc--;
368      argv++;
369      proto = filter_Nam2Proto(argc, argv);
370      if (!argc)
371        log_Printf(LogWARN, "Parse: address/mask is expected.\n");
372      else if (proto == P_NONE) {
373	if (ParseAddr(ipcp, *argv, &filterdata.dst.ipaddr, &filterdata.dst.mask,
374                      &filterdata.dst.width)) {
375          filterdata.dsttype = addrtype(*argv);
376	  argc--;
377	  argv++;
378	} else
379          filterdata.dsttype = T_ADDR;
380	proto = filter_Nam2Proto(argc, argv);
381	if (argc && proto != P_NONE) {
382	  argc--;
383	  argv++;
384	}
385      } else {
386	argc--;
387	argv++;
388      }
389    } else {
390      log_Printf(LogWARN, "Parse: Address/protocol expected.\n");
391      return (0);
392    }
393  } else {
394    argc--;
395    argv++;
396  }
397
398  val = 1;
399  filterdata.proto = proto;
400
401  switch (proto) {
402  case P_TCP:
403    val = ParseUdpOrTcp(argc, argv, P_TCP, &filterdata);
404    break;
405  case P_UDP:
406    val = ParseUdpOrTcp(argc, argv, P_UDP, &filterdata);
407    break;
408  case P_ICMP:
409    val = ParseIcmp(argc, argv, &filterdata);
410    break;
411  case P_IGMP:
412    val = ParseIgmp(argc, argv, &filterdata);
413    break;
414  }
415
416  log_Printf(LogDEBUG, "Parse: Src: %s\n", inet_ntoa(filterdata.src.ipaddr));
417  log_Printf(LogDEBUG, "Parse: Src mask: %s\n", inet_ntoa(filterdata.src.mask));
418  log_Printf(LogDEBUG, "Parse: Dst: %s\n", inet_ntoa(filterdata.dst.ipaddr));
419  log_Printf(LogDEBUG, "Parse: Dst mask: %s\n", inet_ntoa(filterdata.dst.mask));
420  log_Printf(LogDEBUG, "Parse: Proto = %d\n", proto);
421
422  log_Printf(LogDEBUG, "Parse: src:  %s (%d)\n",
423            filter_Op2Nam(filterdata.opt.srcop), filterdata.opt.srcport);
424  log_Printf(LogDEBUG, "Parse: dst:  %s (%d)\n",
425            filter_Op2Nam(filterdata.opt.dstop), filterdata.opt.dstport);
426  log_Printf(LogDEBUG, "Parse: estab: %u\n", filterdata.opt.estab);
427  log_Printf(LogDEBUG, "Parse: syn: %u\n", filterdata.opt.syn);
428  log_Printf(LogDEBUG, "Parse: finrst: %u\n", filterdata.opt.finrst);
429
430  if (val)
431    *ofp = filterdata;
432  return (val);
433}
434
435int
436filter_Set(struct cmdargs const *arg)
437{
438  struct filter *filter;
439
440  if (arg->argc < arg->argn+2)
441    return -1;
442
443  if (!strcmp(arg->argv[arg->argn], "in"))
444    filter = &arg->bundle->filter.in;
445  else if (!strcmp(arg->argv[arg->argn], "out"))
446    filter = &arg->bundle->filter.out;
447  else if (!strcmp(arg->argv[arg->argn], "dial"))
448    filter = &arg->bundle->filter.dial;
449  else if (!strcmp(arg->argv[arg->argn], "alive"))
450    filter = &arg->bundle->filter.alive;
451  else {
452    log_Printf(LogWARN, "filter_Set: %s: Invalid filter name.\n",
453              arg->argv[arg->argn]);
454    return -1;
455  }
456
457  Parse(&arg->bundle->ncp.ipcp, arg->argc - arg->argn - 1,
458        arg->argv + arg->argn + 1, filter->rule);
459  return 0;
460}
461
462const char *
463filter_Action2Nam(int act)
464{
465  static const char *actname[] = { "none   ", "permit ", "deny   " };
466  return actname[act & (A_PERMIT|A_DENY)];
467}
468
469static void
470doShowFilter(struct filterent *fp, struct prompt *prompt)
471{
472  int n;
473
474  for (n = 0; n < MAXFILTERS; n++, fp++) {
475    if (fp->action != A_NONE) {
476      prompt_Printf(prompt, "  %2d %s", n, filter_Action2Nam(fp->action));
477      if (fp->action & A_UHOST)
478        prompt_Printf(prompt, "host ");
479      else if (fp->action & A_UPORT)
480        prompt_Printf(prompt, "port ");
481      else
482        prompt_Printf(prompt, "     ");
483      prompt_Printf(prompt, "%s/%d ", addrstr(fp->src.ipaddr, fp->srctype),
484                    fp->src.width);
485      prompt_Printf(prompt, "%s/%d ", addrstr(fp->dst.ipaddr, fp->dsttype),
486                    fp->dst.width);
487      if (fp->proto) {
488	prompt_Printf(prompt, "%s", filter_Proto2Nam(fp->proto));
489
490	if (fp->opt.srcop)
491	  prompt_Printf(prompt, " src %s %d", filter_Op2Nam(fp->opt.srcop),
492		  fp->opt.srcport);
493	if (fp->opt.dstop)
494	  prompt_Printf(prompt, " dst %s %d", filter_Op2Nam(fp->opt.dstop),
495		  fp->opt.dstport);
496	if (fp->opt.estab)
497	  prompt_Printf(prompt, " estab");
498	if (fp->opt.syn)
499	  prompt_Printf(prompt, " syn");
500	if (fp->opt.finrst)
501	  prompt_Printf(prompt, " finrst");
502      }
503      prompt_Printf(prompt, "\n");
504    }
505  }
506}
507
508int
509filter_Show(struct cmdargs const *arg)
510{
511  if (arg->argc > arg->argn+1)
512    return -1;
513
514  if (arg->argc == arg->argn+1) {
515    struct filter *filter;
516
517    if (!strcmp(arg->argv[arg->argn], "in"))
518      filter = &arg->bundle->filter.in;
519    else if (!strcmp(arg->argv[arg->argn], "out"))
520      filter = &arg->bundle->filter.out;
521    else if (!strcmp(arg->argv[arg->argn], "dial"))
522      filter = &arg->bundle->filter.dial;
523    else if (!strcmp(arg->argv[arg->argn], "alive"))
524      filter = &arg->bundle->filter.alive;
525    else
526      return -1;
527    doShowFilter(filter->rule, arg->prompt);
528  } else {
529    struct filter *filter[4];
530    int f;
531
532    filter[0] = &arg->bundle->filter.in;
533    filter[1] = &arg->bundle->filter.out;
534    filter[2] = &arg->bundle->filter.dial;
535    filter[3] = &arg->bundle->filter.alive;
536    for (f = 0; f < 4; f++) {
537      if (f)
538        prompt_Printf(arg->prompt, "\n");
539      prompt_Printf(arg->prompt, "%s:\n", filter[f]->name);
540      doShowFilter(filter[f]->rule, arg->prompt);
541    }
542  }
543
544  return 0;
545}
546
547static const char *protoname[] = { "none", "tcp", "udp", "icmp", "igmp" };
548
549const char *
550filter_Proto2Nam(int proto)
551{
552  if (proto >= sizeof protoname / sizeof protoname[0])
553    return "unknown";
554  return protoname[proto];
555}
556
557static int
558filter_Nam2Proto(int argc, char const *const *argv)
559{
560  int proto;
561
562  if (argc == 0)
563    proto = 0;
564  else
565    for (proto = sizeof protoname / sizeof protoname[0] - 1; proto; proto--)
566      if (!strcasecmp(*argv, protoname[proto]))
567        break;
568
569  return proto;
570}
571
572static const char *opname[] = {"none", "eq", "gt", "unknown", "lt"};
573
574const char *
575filter_Op2Nam(int op)
576{
577  if (op >= sizeof opname / sizeof opname[0])
578    return "unknown";
579  return opname[op];
580
581}
582
583static int
584filter_Nam2Op(const char *cp)
585{
586  int op;
587
588  for (op = sizeof opname / sizeof opname[0] - 1; op; op--)
589    if (!strcasecmp(cp, opname[op]))
590      break;
591
592  return op;
593}
594
595void
596filter_AdjustAddr(struct filter *filter, struct in_addr *my_ip,
597                  struct in_addr *peer_ip)
598{
599  struct filterent *fp;
600  int n;
601
602  for (fp = filter->rule, n = 0; n < MAXFILTERS; fp++, n++)
603    if (fp->action != A_NONE) {
604      if (my_ip) {
605        if (fp->srctype == T_MYADDR)
606          fp->src.ipaddr = *my_ip;
607        if (fp->dsttype == T_MYADDR)
608          fp->dst.ipaddr = *my_ip;
609      }
610      if (peer_ip) {
611        if (fp->srctype == T_HISADDR)
612          fp->src.ipaddr = *peer_ip;
613        if (fp->dsttype == T_HISADDR)
614          fp->dst.ipaddr = *peer_ip;
615      }
616    }
617}
618