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[tcpdump] / print-gre.c
index db6ebfacaad234ee0f8bbb718b03cc658cd40275..1d545b3f8b076a2039e2e8b3300d34d7551b8f86 100644 (file)
@@ -44,9 +44,7 @@
  * Virtual Subnet ID (VSID) and an 8-bit FlowID.
  */
 
-#ifdef HAVE_CONFIG_H
 #include <config.h>
-#endif
 
 #include "netdissect-stdinc.h"
 
 #include "addrtostr.h"
 #include "extract.h"
 #include "ethertype.h"
-
-
-#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_AP          0x0080          /* acknowledgment# present */
+#include "gre.h"
 
 static const struct tok gre_flag_values[] = {
     { GRE_CP, "checksum present"},
@@ -84,7 +75,12 @@ static const struct tok gre_flag_values[] = {
 /*
  * Ethertype values used for GRE (but not elsewhere?).
  */
+#define GRE_CDP                        0x2000  /* Cisco Discovery Protocol */
+#define GRE_NHRP               0x2001  /* Next Hop Resolution Protocol */
+#define GRE_MIKROTIK_EOIP      0x6400  /* MikroTik RouterBoard Ethernet over IP (EoIP) */
+#define GRE_ERSPAN_III         0x22eb
 #define GRE_WCCP               0x883e  /* Web Cache C* Protocol */
+#define GRE_ERSPAN_I_II                0x88be
 
 struct wccp_redirect {
        nd_uint8_t      flags;
@@ -234,7 +230,7 @@ gre_print_0(netdissect_options *ndo, const u_char *bp, u_int length)
                 * use it for keep-alives; see, for example,
                 * https://www.cisco.com/c/en/us/support/docs/ip/generic-routing-encapsulation-gre/118370-technote-gre-00.html#anc1
                 */
-               printf("keep-alive");
+               ND_PRINT("keep-alive");
                break;
        case GRE_WCCP:
                /*
@@ -242,13 +238,13 @@ gre_print_0(netdissect_options *ndo, const u_char *bp, u_int length)
                 *
                 * This may either just mean "IPv4" or it may mean
                 * "IPv4 preceded by a WCCP redirect header".  We
-                * check to seeif the first octet looks like the
+                * check to see if the first octet looks like the
                 * beginning of an IPv4 header and, if not, dissect
                 * it "IPv4 preceded by a WCCP redirect header",
                 * otherwise we dissect it as just IPv4.
                 *
                 * See "Packet redirection" in draft-forster-wrec-wccp-v1-00,
-                * scetion 4.12 "Traffic Forwarding" in
+                * section 4.12 "Traffic Forwarding" in
                 * draft-wilson-wrec-wccp-v2-01, and section 3.12.1
                 * "Forwarding using GRE Encapsulation" in
                 * draft-param-wccp-v2rev1-01.
@@ -278,10 +274,9 @@ gre_print_0(netdissect_options *ndo, const u_char *bp, u_int length)
                        bp += sizeof(*wccp);
                        len -= sizeof(*wccp);
 
-                       printf(": ");
+                       ND_PRINT(": ");
                }
                /* FALLTHROUGH */
-               break;
        case ETHERTYPE_IP:
                ip_print(ndo, bp, len);
                break;
@@ -307,6 +302,18 @@ gre_print_0(netdissect_options *ndo, const u_char *bp, u_int length)
        case ETHERTYPE_NSH:
                nsh_print(ndo, bp, len);
                break;
+       case GRE_ERSPAN_I_II:
+               erspan_i_ii_print(ndo, flags, bp, len);
+               break;
+       case GRE_ERSPAN_III:
+               erspan_iii_print(ndo, bp, len);
+               break;
+       case GRE_CDP:
+               cdp_print(ndo, bp, len);
+               break;
+       case GRE_NHRP:
+               nhrp_print(ndo, bp, len);
+               break;
        default:
                ND_PRINT("gre-proto-0x%x", prot);
        }
@@ -336,16 +343,48 @@ gre_print_1(netdissect_options *ndo, const u_char *bp, u_int length)
        len -= 2;
        bp += 2;
 
+       /*
+        * This version is used for two purposes:
+        *
+        *  RFC 2637 PPTP;
+        *  Some Mikrotik Ethernet-over-IP hack.
+        */
+       switch (prot) {
+       case GRE_MIKROTIK_EOIP:
+               /*
+                * The MikroTik hack uses only the key field, and uses it
+                * for its own purposes.  If anything other than the version
+                * and K bit are set, report an error and give up.
+                */
+               if ((flags & ~GRE_VERS_MASK) != GRE_KP) {
+                       ND_PRINT(" unknown-eoip-flags-%04x!", flags);
+                       return;
+               }
+               break;
+       default:
+               /*
+                * XXX - what should we do if it's not ETHERTYPE_PPP?
+                */
+               break;
+       }
 
        if (flags & GRE_KP) {
-               uint32_t k;
+               /* Skip payload length? */
+               ND_ICHECK_U(len, <, 2);
+               ND_TCHECK_2(bp);
+               len -= 2;
+               bp += 2;
 
-               ND_ICHECK_U(len, <, 4);
-               k = GET_BE_U_4(bp);
-               ND_PRINT(", call %u", k & 0xffff);
-               len -= 4;
-               bp += 4;
-       }
+               ND_ICHECK_U(len, <, 2);
+               if (prot == GRE_MIKROTIK_EOIP) {
+                       /* Non-standard */
+                       ND_PRINT(", tunnel-id %u", GET_BE_U_2(bp));
+               } else
+                       ND_PRINT(", call %u", GET_BE_U_2(bp));
+               len -= 2;
+               bp += 2;
+       } else
+               ND_PRINT(", (ERROR: K flag not set)");
 
        if (flags & GRE_SP) {
                ND_ICHECK_U(len, <, 4);
@@ -361,7 +400,10 @@ gre_print_1(netdissect_options *ndo, const u_char *bp, u_int length)
                len -= 4;
        }
 
-       if ((flags & GRE_SP) == 0)
+       /*
+        * More non-standard EoIP behavior.
+        */
+       if (prot != GRE_MIKROTIK_EOIP && (flags & GRE_SP) == 0)
                ND_PRINT(", no-payload");
 
        if (ndo->ndo_eflag)
@@ -370,7 +412,10 @@ gre_print_1(netdissect_options *ndo, const u_char *bp, u_int length)
 
        ND_PRINT(", length %u",length);
 
-       if ((flags & GRE_SP) == 0)
+       /*
+        * More non-standard EoIP behavior.
+        */
+       if (prot != GRE_MIKROTIK_EOIP && (flags & GRE_SP) == 0)
                return;
 
        if (ndo->ndo_vflag < 1)
@@ -382,6 +427,13 @@ gre_print_1(netdissect_options *ndo, const u_char *bp, u_int length)
        case ETHERTYPE_PPP:
                ppp_print(ndo, bp, len);
                break;
+       case GRE_MIKROTIK_EOIP:
+               /* MikroTik RouterBoard Ethernet over IP (EoIP) */
+               if (len == 0)
+                       ND_PRINT("keepalive");
+               else
+                       ether_print(ndo, bp, len, ND_BYTES_AVAILABLE_AFTER(bp), NULL, NULL);
+               break;
        default:
                ND_PRINT("gre-proto-0x%x", prot);
                break;