gre: support CDP over GRE.

Taken from the OpenBSD version of tcpdump.

diff --git a/print-gre.c b/print-gre.c
index a174268eaf30d73a861f1182070eea64797fd6e1..40496ca7bae49244920bd0eb01e1989f7956abb4 100644 (file)
--- a/print-gre.c
+++ b/print-gre.c
@@ -84,6 +84,7 @@ static const struct tok gre_flag_values[] = {
 /*
  * Ethertype values used for GRE (but not elsewhere?).
  */
+#define GRE_CDP                        0x2000  /* Cisco Discovery Protocol */
 #define GRE_WCCP               0x883e  /* Web Cache C* Protocol */
 
 struct wccp_redirect {
@@ -306,6 +307,9 @@ gre_print_0(netdissect_options *ndo, const u_char *bp, u_int length)
        case ETHERTYPE_NSH:
                nsh_print(ndo, bp, len);
                break;
+       case GRE_CDP:
+               cdp_print(ndo, bp, len);
+               break;
        default:
                ND_PRINT("gre-proto-0x%x", prot);
        }

diff --git a/tests/various_gre.out b/tests/various_gre.out
index 3363768cef7e32b0e473201bcfa969a0a175ee93..6c1b4ff1dfd8b58100843baf6496c4981d188bf4 100644 (file)
--- a/tests/various_gre.out
+++ b/tests/various_gre.out
@@ -140,7 +140,21 @@
        root-id 84bd.aa:bb:cc:00:03:00, root-pathcost 0
    49  09:45:19.766290 IP (tos 0x0, ttl 255, id 152, offset 0, flags [none], proto GRE (47), length 381)
     10.172.64.6 > 10.172.64.7: GREv0, Flags [key present], key=0x28, length 361
-       gre-proto-0x2000
+       CDPv2, ttl: 180s, checksum: 0xa82e (unverified), length 353
+       Device-ID (0x01), value length: 2 bytes: 'R1'
+       Version String (0x05), value length: 257 bytes: 
+         Cisco IOS Software, Linux Software (I86BI_LINUX-ADVENTERPRISEK9-M), Version 15.5(3)S2, DEVELOPMENT TEST SOFTWARE
+         Technical Support: http://www.cisco.com/techsupport
+         Copyright (c) 1986-2016 by Cisco Systems, Inc.
+         Compiled Mon 08-Feb-16 20:48 by prod_rel_team
+       Platform (0x06), value length: 10 bytes: 'Linux Unix'
+       Address (0x02), value length: 13 bytes: IPv4 (1) 172.17.1.54
+       Port-ID (0x03), value length: 8 bytes: 'Tunnel40'
+       Capability (0x04), value length: 4 bytes: (0x00000001): Router
+       Prefixes (0x07), value length: 5 bytes:  IPv4 Prefixes (1): 10.172.64.6/31
+       Management Addresses (0x16), value length: 13 bytes: IPv4 (1) 172.17.1.54
+       unknown field type (0x1b), value length: 1 byte: 
+         0x0000:  00
    50  09:45:20.096783 STP 802.1d, Config, Flags [none], bridge-id 8001.aa:bb:cc:00:03:00.8002, length 35
        message-age 0.00s, max-age 20.00s, hello-time 2.00s, forwarding-delay 15.00s
        root-id 8001.aa:bb:cc:00:03:00, root-pathcost 0
@@ -182,7 +196,21 @@
        Neighbor (0x0004) TLV, length 10, aa:bb:cc:00:03:10
    63  09:45:27.181709 IP (tos 0x0, ttl 255, id 172, offset 0, flags [none], proto GRE (47), length 381)
     10.172.64.7 > 10.172.64.6: GREv0, Flags [key present], key=0x28, length 361
-       gre-proto-0x2000
+       CDPv2, ttl: 180s, checksum: 0xa82b (unverified), length 353
+       Device-ID (0x01), value length: 2 bytes: 'R2'
+       Version String (0x05), value length: 257 bytes: 
+         Cisco IOS Software, Linux Software (I86BI_LINUX-ADVENTERPRISEK9-M), Version 15.5(3)S2, DEVELOPMENT TEST SOFTWARE
+         Technical Support: http://www.cisco.com/techsupport
+         Copyright (c) 1986-2016 by Cisco Systems, Inc.
+         Compiled Mon 08-Feb-16 20:48 by prod_rel_team
+       Platform (0x06), value length: 10 bytes: 'Linux Unix'
+       Address (0x02), value length: 13 bytes: IPv4 (1) 172.17.1.55
+       Port-ID (0x03), value length: 8 bytes: 'Tunnel40'
+       Capability (0x04), value length: 4 bytes: (0x00000001): Router
+       Prefixes (0x07), value length: 5 bytes:  IPv4 Prefixes (1): 10.172.64.6/31
+       Management Addresses (0x16), value length: 13 bytes: IPv4 (1) 172.17.1.55
+       unknown field type (0x1b), value length: 1 byte: 
+         0x0000:  00
    64  09:45:27.478420 IP (tos 0xc0, ttl 255, id 174, offset 0, flags [none], proto GRE (47), length 64)
     10.172.64.7 > 10.172.64.6: GREv0, Flags [key present], key=0x28, length 44
        gre-proto-0x8909