Avoiding conditional directives that break statements

[tcpdump] / print-gre.c

diff --git a/print-gre.c b/print-gre.c
index cf2ba469265932a148842f644770fafa6e1be99a..187a5b9f48297a9b260ea4d1e4a3328d01ccc871 100644 (file)
--- a/print-gre.c
+++ b/print-gre.c
@@ -1,173 +1,395 @@
+/*     $OpenBSD: print-gre.c,v 1.6 2002/10/30 03:04:04 fgsch Exp $     */
+

 /*
 /*

- * Copyright (c) 1996
- *      The Regents of the University of California.  All rights reserved.
- *
- * Redistribution and use in source and binary forms are permitted
- * provided that the above copyright notice and this paragraph are
- * duplicated in all such forms and that any documentation,
- * advertising materials, and other materials related to such
- * distribution and use acknowledge that the software was developed
- * by the University of California, Lawrence Berkeley Laboratory,
- * Berkeley, CA.  The name of the University may not be used to
- * endorse or promote products derived from this software without
- * specific prior written permission.
- * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
- * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
- * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ * Copyright (c) 2002 Jason L. Wright ([email protected])
+ * All rights reserved.

  *
  *

- * Initial contribution from John Hawkinson <[email protected]>
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *     This product includes software developed by Jason L. Wright
+ * 4. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.

  *
  *

- * This module implements support for decoding GRE (Generic Routing
- * Encapsulation) tunnels; they're documented in RFC1701 and RFC1702.
- * This code only supports the IP encapsulation thereof.
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.

  */
 
  */
 

-#ifndef lint
-static const char rcsid[] =
-    "@(#) $Header: /tcpdump/master/tcpdump/print-gre.c,v 1.10 2001-02-03 20:21:28 fenner Exp $";
-#endif
+/*
+ * netdissect printer for GRE - Generic Routing Encapsulation
+ * RFC1701 (GRE), RFC1702 (GRE IPv4), and RFC2637 (Enhanced GRE)
+ */

 
 #ifdef HAVE_CONFIG_H
 #include "config.h"
 #endif
 
 
 #ifdef HAVE_CONFIG_H
 #include "config.h"
 #endif
 

-#include <sys/param.h>
-#include <sys/time.h>
-#include <sys/uio.h>
-#include <sys/socket.h>
-
-#include <netinet/in.h>
-
-#include <netdb.h>
-#include <stdio.h>
-
-#include "interface.h"
-#include "addrtoname.h"
-#include "extract.h"           /* must come after interface.h */
-
-#define GRE_SIZE (20)
-
-struct gre {
-       u_short flags;
-       u_short proto;
-       union {
-               struct gre_ckof {
-                       u_short cksum;
-                       u_short offset;
-               }        gre_ckof;
-               u_int32_t key;
-               u_int32_t seq;
-       }     gre_void1;
-       union {
-               u_int32_t key;
-               u_int32_t seq;
-               u_int32_t routing;
-       }     gre_void2;
-       union {
-               u_int32_t seq;
-               u_int32_t routing;
-       }     gre_void3;
-       union {
-               u_int32_t routing;
-       }     gre_void4;
-};
+#include <netdissect-stdinc.h>

 
 

-/* RFC 2784 - GRE */
-#define GRE_CP         0x8000  /* Checksum Present */
-#define GRE_VER_MASK   0x0007  /* Version */
+#include <string.h>

 
 

-/* RFC 2890 - Key and Sequence extensions to GRE */
-#define GRE_KP         0x2000  /* Key Present */
-#define GRE_SP         0x1000  /* Sequence Present */
+#include "netdissect.h"
+#include "addrtostr.h"
+#include "extract.h"
+#include "ethertype.h"

 
 

-/* Legacy from RFC 1700 */
-#define GRE_RP         0x4000  /* Routing Present */
-#define GRE_sP         0x0800  /* strict source route present */
-#define GRE_RECUR_MASK 0x0700  /* Recursion Control */
-#define GRE_RECUR_SHIFT        8
+static const char tstr[] = "[|gre]";

 
 

-/* "Enhanced GRE" from RFC2637 - PPTP */
-#define GRE_AP         0x0080  /* Ack present */
+#define        GRE_CP          0x8000          /* checksum present */
+#define        GRE_RP          0x4000          /* routing present */
+#define        GRE_KP          0x2000          /* key present */
+#define        GRE_SP          0x1000          /* sequence# present */
+#define        GRE_sP          0x0800          /* source routing */
+#define        GRE_RECRS       0x0700          /* recursion count */
+#define        GRE_AP          0x0080          /* acknowledgment# present */

 
 

-#define GRE_MBZ_MASK   0x0078  /* not defined */
+static const struct tok gre_flag_values[] = {
+    { GRE_CP, "checksum present"},
+    { GRE_RP, "routing present"},
+    { GRE_KP, "key present"},
+    { GRE_SP, "sequence# present"},
+    { GRE_sP, "source routing present"},
+    { GRE_RECRS, "recursion count"},
+    { GRE_AP, "ack present"},
+    { 0, NULL }
+};
+
+#define        GRE_VERS_MASK   0x0007          /* protocol version */
+
+/* source route entry types */
+#define        GRESRE_IP       0x0800          /* IP */
+#define        GRESRE_ASN      0xfffe          /* ASN */
+
+static void gre_print_0(netdissect_options *, const u_char *, u_int);
+static void gre_print_1(netdissect_options *, const u_char *, u_int);
+static void gre_sre_print(netdissect_options *, uint16_t, uint8_t, uint8_t, const u_char *, u_int);
+static void gre_sre_ip_print(netdissect_options *, uint8_t, uint8_t, const u_char *, u_int);
+static void gre_sre_asn_print(netdissect_options *, uint8_t, uint8_t, const u_char *, u_int);

 
 

-/*
- * Deencapsulate and print a GRE-tunneled IP datagram
- *
- * XXX PPTP needs to interpret the "key" field...
- */

 void
 void

-gre_print(const u_char *bp, u_int length)
+gre_print(netdissect_options *ndo, const u_char *bp, u_int length)

 {
 {

-       const u_char *cp = bp + 4;
-       const struct gre *gre;
-       u_short flags, proto, extracted_ethertype;
-
-       gre = (const struct gre *)bp;
-
-       TCHECK(gre->proto);
-       flags = EXTRACT_16BITS(&gre->flags);
-       proto = EXTRACT_16BITS(&gre->proto);
-
-       if (flags) {
-               /* Decode the flags */
-               putchar('[');
-               if (flags & GRE_CP)
-                       putchar('C');
-               if (flags & GRE_RP)
-                       putchar('R');
-               if (flags & GRE_KP)
-                       putchar('K');
-               if (flags & GRE_SP)
-                       putchar('S');
-               if (flags & GRE_sP)
-                       putchar('s');
-               if (flags & GRE_AP)
-                       putchar('A');
-               if (flags & GRE_RECUR_MASK)
-                       printf("R%x", (flags & GRE_RECUR_MASK) >> GRE_RECUR_SHIFT);
-               if (flags & GRE_VER_MASK)
-                       printf("v%x", flags & GRE_VER_MASK);
-               if (flags & GRE_MBZ_MASK)
-                       printf("!%x", flags & GRE_MBZ_MASK);
-               fputs("] ", stdout);
-       }
-       /* Checksum & Offset are present */
-       if ((flags & GRE_CP) | (flags & GRE_RP))
-               cp += 4;
-
-       /* We don't support routing fields (variable length) now. Punt. */
-       if (flags & GRE_RP)
+       u_int len = length, vers;
+
+       if (len < 2) {
+               ND_PRINT((ndo, "%s", tstr));

                return;
                return;

+       }
+       vers = EXTRACT_16BITS(bp) & GRE_VERS_MASK;
+        ND_PRINT((ndo, "GREv%u",vers));
+
+        switch(vers) {
+        case 0:
+            gre_print_0(ndo, bp, len);
+            break;
+        case 1:
+            gre_print_1(ndo, bp, len);
+            break;
+       default:
+            ND_PRINT((ndo, " ERROR: unknown-version"));
+            break;
+        }
+}
+
+static void
+gre_print_0(netdissect_options *ndo, const u_char *bp, u_int length)
+{
+       u_int len = length;
+       uint16_t flags, prot;
+
+       flags = EXTRACT_16BITS(bp);
+        if (ndo->ndo_vflag)
+            ND_PRINT((ndo, ", Flags [%s]",
+                   bittok2str(gre_flag_values,"none",flags)));
+
+       len -= 2;
+       bp += 2;
+
+       if (len < 2)
+               goto trunc;
+       prot = EXTRACT_16BITS(bp);
+       len -= 2;
+       bp += 2;
+
+       if ((flags & GRE_CP) | (flags & GRE_RP)) {
+               if (len < 2)
+                       goto trunc;
+               if (ndo->ndo_vflag)
+                       ND_PRINT((ndo, ", sum 0x%x", EXTRACT_16BITS(bp)));
+               bp += 2;
+               len -= 2;
+
+               if (len < 2)
+                       goto trunc;
+               ND_PRINT((ndo, ", off 0x%x", EXTRACT_16BITS(bp)));
+               bp += 2;
+               len -= 2;
+       }

 
        if (flags & GRE_KP) {
 
        if (flags & GRE_KP) {

-               TCHECK2(*cp, 4);
-               if (vflag > 1)
-                       printf("K:%08x ", EXTRACT_32BITS(cp));
-               cp += 4;        /* skip key */
+               if (len < 4)
+                       goto trunc;
+               ND_PRINT((ndo, ", key=0x%x", EXTRACT_32BITS(bp)));
+               bp += 4;
+               len -= 4;

        }
        }

+

        if (flags & GRE_SP) {
        if (flags & GRE_SP) {

-               TCHECK2(*cp, 4);
-               if (vflag > 1)
-                       printf("S:%08x ", EXTRACT_32BITS(cp));
-               cp += 4;        /* skip seq */
+               if (len < 4)
+                       goto trunc;
+               ND_PRINT((ndo, ", seq %u", EXTRACT_32BITS(bp)));
+               bp += 4;
+               len -= 4;

        }
        }

-       if (flags & GRE_AP && (flags & GRE_VER_MASK) >= 1) {
-               TCHECK2(*cp, 4);
-               if (vflag > 1)
-                       printf("A:%08x ", EXTRACT_32BITS(cp));
-               cp += 4;        /* skip ack */
+
+       if (flags & GRE_RP) {
+               for (;;) {
+                       uint16_t af;
+                       uint8_t sreoff;
+                       uint8_t srelen;
+
+                       if (len < 4)
+                               goto trunc;
+                       af = EXTRACT_16BITS(bp);
+                       sreoff = *(bp + 2);
+                       srelen = *(bp + 3);
+                       bp += 4;
+                       len -= 4;
+
+                       if (af == 0 && srelen == 0)
+                               break;
+
+                       gre_sre_print(ndo, af, sreoff, srelen, bp, len);
+
+                       if (len < srelen)
+                               goto trunc;
+                       bp += srelen;
+                       len -= srelen;
+               }

        }
 
        }
 

-       TCHECK(cp[0]);
+        if (ndo->ndo_eflag)
+            ND_PRINT((ndo, ", proto %s (0x%04x)",
+                   tok2str(ethertype_values,"unknown",prot),
+                   prot));
+
+        ND_PRINT((ndo, ", length %u",length));

 
 

-       length -= cp - bp;
-       if (ether_encap_print(proto, cp, length, length,
-           &extracted_ethertype) == 0)
-               printf("gre-proto-0x%04X", proto);
+        if (ndo->ndo_vflag < 1)
+            ND_PRINT((ndo, ": ")); /* put in a colon as protocol demarc */
+        else
+            ND_PRINT((ndo, "\n\t")); /* if verbose go multiline */
+
+       switch (prot) {
+       case ETHERTYPE_IP:
+               ip_print(ndo, bp, len);
+               break;
+       case ETHERTYPE_IPV6:
+               ip6_print(ndo, bp, len);
+               break;
+       case ETHERTYPE_MPLS:
+               mpls_print(ndo, bp, len);
+               break;
+       case ETHERTYPE_IPX:
+               ipx_print(ndo, bp, len);
+               break;
+       case ETHERTYPE_ATALK:
+               atalk_print(ndo, bp, len);
+               break;
+       case ETHERTYPE_GRE_ISO:
+               isoclns_print(ndo, bp, len, len);
+               break;
+       case ETHERTYPE_TEB:
+               ether_print(ndo, bp, len, len, NULL, NULL);
+               break;
+       default:
+               ND_PRINT((ndo, "gre-proto-0x%x", prot));
+       }

        return;
 
 trunc:
        return;
 
 trunc:

-       fputs("[|gre]", stdout);
+       ND_PRINT((ndo, "%s", tstr));
+}

 
 

+static void
+gre_print_1(netdissect_options *ndo, const u_char *bp, u_int length)
+{
+       u_int len = length;
+       uint16_t flags, prot;
+
+       flags = EXTRACT_16BITS(bp);
+       len -= 2;
+       bp += 2;
+
+       if (ndo->ndo_vflag)
+            ND_PRINT((ndo, ", Flags [%s]",
+                   bittok2str(gre_flag_values,"none",flags)));
+
+       if (len < 2)
+               goto trunc;
+       prot = EXTRACT_16BITS(bp);
+       len -= 2;
+       bp += 2;
+
+
+       if (flags & GRE_KP) {
+               uint32_t k;
+
+               if (len < 4)
+                       goto trunc;
+               k = EXTRACT_32BITS(bp);
+               ND_PRINT((ndo, ", call %d", k & 0xffff));
+               len -= 4;
+               bp += 4;
+       }
+
+       if (flags & GRE_SP) {
+               if (len < 4)
+                       goto trunc;
+               ND_PRINT((ndo, ", seq %u", EXTRACT_32BITS(bp)));
+               bp += 4;
+               len -= 4;
+       }
+
+       if (flags & GRE_AP) {
+               if (len < 4)
+                       goto trunc;
+               ND_PRINT((ndo, ", ack %u", EXTRACT_32BITS(bp)));
+               bp += 4;
+               len -= 4;
+       }
+
+       if ((flags & GRE_SP) == 0)
+               ND_PRINT((ndo, ", no-payload"));
+
+        if (ndo->ndo_eflag)
+            ND_PRINT((ndo, ", proto %s (0x%04x)",
+                   tok2str(ethertype_values,"unknown",prot),
+                   prot));
+
+        ND_PRINT((ndo, ", length %u",length));
+
+        if ((flags & GRE_SP) == 0)
+            return;
+
+        if (ndo->ndo_vflag < 1)
+            ND_PRINT((ndo, ": ")); /* put in a colon as protocol demarc */
+        else
+            ND_PRINT((ndo, "\n\t")); /* if verbose go multiline */
+
+       switch (prot) {
+       case ETHERTYPE_PPP:
+               ppp_print(ndo, bp, len);
+               break;
+       default:
+               ND_PRINT((ndo, "gre-proto-0x%x", prot));
+               break;
+       }
+       return;
+
+trunc:
+       ND_PRINT((ndo, "%s", tstr));
+}
+
+static void
+gre_sre_print(netdissect_options *ndo, uint16_t af, uint8_t sreoff,
+    uint8_t srelen, const u_char *bp, u_int len)
+{
+       switch (af) {
+       case GRESRE_IP:
+               ND_PRINT((ndo, ", (rtaf=ip"));
+               gre_sre_ip_print(ndo, sreoff, srelen, bp, len);
+               ND_PRINT((ndo, ")"));
+               break;
+       case GRESRE_ASN:
+               ND_PRINT((ndo, ", (rtaf=asn"));
+               gre_sre_asn_print(ndo, sreoff, srelen, bp, len);
+               ND_PRINT((ndo, ")"));
+               break;
+       default:
+               ND_PRINT((ndo, ", (rtaf=0x%x)", af));
+       }
+}
+
+static void
+gre_sre_ip_print(netdissect_options *ndo, uint8_t sreoff, uint8_t srelen,
+                 const u_char *bp, u_int len)
+{
+       const u_char *up = bp;
+       char buf[INET_ADDRSTRLEN];
+
+       if (sreoff & 3) {
+               ND_PRINT((ndo, ", badoffset=%u", sreoff));
+               return;
+       }
+       if (srelen & 3) {
+               ND_PRINT((ndo, ", badlength=%u", srelen));
+               return;
+       }
+       if (sreoff >= srelen) {
+               ND_PRINT((ndo, ", badoff/len=%u/%u", sreoff, srelen));
+               return;
+       }
+
+       for (;;) {
+               if (len < 4 || srelen == 0)
+                       return;
+
+               addrtostr(bp, buf, sizeof(buf));
+               ND_PRINT((ndo, " %s%s",
+                   ((bp - up) == sreoff) ? "*" : "", buf));
+
+               bp += 4;
+               len -= 4;
+               srelen -= 4;
+       }
+}
+
+static void
+gre_sre_asn_print(netdissect_options *ndo, uint8_t sreoff, uint8_t srelen,
+                  const u_char *bp, u_int len)
+{
+       const u_char *up = bp;
+
+       if (sreoff & 1) {
+               ND_PRINT((ndo, ", badoffset=%u", sreoff));
+               return;
+       }
+       if (srelen & 1) {
+               ND_PRINT((ndo, ", badlength=%u", srelen));
+               return;
+       }
+       if (sreoff >= srelen) {
+               ND_PRINT((ndo, ", badoff/len=%u/%u", sreoff, srelen));
+               return;
+       }
+
+       for (;;) {
+               if (len < 2 || srelen == 0)
+                       return;
+
+               ND_PRINT((ndo, " %s%x",
+                   ((bp - up) == sreoff) ? "*" : "",
+                   EXTRACT_16BITS(bp)));
+
+               bp += 2;
+               len -= 2;
+               srelen -= 2;
+       }

 }
 }