From: dlg <dlg@openbsd.org>
Date: Thu, 8 Feb 2018 22:56:28 +0000 (+0000)
Subject: have a go at decoding cisco wccp gre packets, and let them fall into IP.
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=05cff7c060415d6838e975bb7dedb6be05fe555f;p=openbsd

have a go at decoding cisco wccp gre packets, and let them fall into IP.
---

diff --git a/usr.sbin/tcpdump/print-gre.c b/usr.sbin/tcpdump/print-gre.c
index 4890cf87517..19be61f5b66 100644
--- a/usr.sbin/tcpdump/print-gre.c
+++ b/usr.sbin/tcpdump/print-gre.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: print-gre.c,v 1.15 2018/02/08 09:01:45 dlg Exp $	*/
+/*	$OpenBSD: print-gre.c,v 1.16 2018/02/08 22:56:28 dlg Exp $	*/
 
 /*
  * Copyright (c) 2002 Jason L. Wright (jason@thought.net)
@@ -66,6 +66,17 @@
 #define NVGRE_FLOWID_MASK	0x000000ffU
 #define NVGRE_FLOWID_SHIFT	0
 
+#define GRE_WCCP	0x883e
+
+struct wccp_redirect {
+	uint8_t		flags;
+#define WCCP_D			(1 << 7)
+#define WCCP_A			(1 << 6)
+	uint8_t		ServiceId;
+	uint8_t		AltBucket;
+	uint8_t		PriBucket;
+};
+
 void gre_print_0(const u_char *, u_int);
 void gre_print_1(const u_char *, u_int);
 void gre_sre_print(u_int16_t, u_int8_t, u_int8_t, const u_char *, u_int);
@@ -207,6 +218,28 @@ gre_print_0(const u_char *p, u_int length)
 	case 0:
 		printf("keep-alive");
 		break;
+	case GRE_WCCP: {
+		struct wccp_redirect *wccp;
+
+		printf("wccp ");
+		if (l < sizeof(*wccp)) {
+			printf("[|wccp]");
+			return;
+		}
+
+		wccp = (struct wccp_redirect *)p;
+
+		printf("D:%c A:%c SId:%u Alt:%u Pri:%u",
+		    (wccp->flags & WCCP_D) ? '1' : '0',
+		    (wccp->flags & WCCP_A) ? '1' : '0',
+		    wccp->ServiceId, wccp->AltBucket, wccp->PriBucket);
+
+		p += sizeof(*wccp);
+		l -= sizeof(*wccp);
+
+		printf(": ");
+		/* FALLTHROUGH */
+	}
 	case ETHERTYPE_IP:
 		ip_print(p, length);
 		break;