/* \summary: Generic Protocol Extension for VXLAN (VXLAN GPE) printer */
-/* specification: draft-ietf-nvo3-vxlan-gpe-01 */
+/* specification: draft-ietf-nvo3-vxlan-gpe-12 */
-#ifdef HAVE_CONFIG_H
#include <config.h>
-#endif
#include "netdissect-stdinc.h"
+#define ND_LONGJMP_FROM_TCHECK
#include "netdissect.h"
#include "extract.h"
+#define VXLAN_GPE_VER 0x30 /* GPE */
+#define VXLAN_GPE_SHIFT 4
+#define VXLAN_GPE_VER_0 0x0
+#define VXLAN_GPE_I 0x08 /* Instance Bit */
+#define VXLAN_GPE_P 0x04 /* GPE Next Protocol */
+#define VXLAN_GPE_B 0x02 /* GPE BUM Traffic */
+#define VXLAN_GPE_O 0x01 /* GPE OAM Flag */
+
static const struct tok vxlan_gpe_flags [] = {
- { 0x08, "I" },
- { 0x04, "P" },
- { 0x01, "O" },
+ { VXLAN_GPE_I, "I" },
+ { VXLAN_GPE_P, "P" },
+ { VXLAN_GPE_B, "B" },
+ { VXLAN_GPE_O, "O" },
{ 0, NULL }
};
+#define VXLAN_GPE_PROTO_RESERVED 0x00
+#define VXLAN_GPE_PROTO_IPV4 0x01
+#define VXLAN_GPE_PROTO_IPV6 0x02
+#define VXLAN_GPE_PROTO_ETHERNET 0x03
+#define VXLAN_GPE_PROTO_NSH 0x04
+
#define VXLAN_GPE_HDR_LEN 8
/*
- * VXLAN GPE header, draft-ietf-nvo3-vxlan-gpe-01
+ * VXLAN GPE header, draft-ietf-nvo3-vxlan-gpe-12
* Generic Protocol Extension for VXLAN
*
* 0 1 2 3
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
- * |R|R|Ver|I|P|R|O| Reserved |Next Protocol |
+ * |R|R|Ver|I|P|B|O| Reserved |Next Protocol |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | VXLAN Network Identifier (VNI) | Reserved |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
void
vxlan_gpe_print(netdissect_options *ndo, const u_char *bp, u_int len)
{
- uint8_t flags;
+ uint8_t flags, ver;
uint8_t next_protocol;
- uint32_t vni;
+ /*
+ * XXX - OpenBSD has a single dissector for VXLAN and VXLAN-GPE,
+ * using the flag bits to distinguish between them.
+ *
+ * draft-ietf-nvo3-vxlan-gpe-12, the final VXLAN-GPE draft, says
+ * that VXLAN-GPE uses port 4790, rather than VXLAN's port 4789,
+ * and that the P flag bit must be set for VXLAN-GPE packets,
+ * indicating that the header includes a "next protocol" field,
+ * and that if a packet with the P it not set is received on
+ * port 4790, "the "Next Protocol" field must be set to zero and
+ * the payload MUST be ETHERNET(L2) as defined by [RFC7348]."
+ */
ndo->ndo_protocol = "vxlan_gpe";
- if (len < VXLAN_GPE_HDR_LEN)
- goto trunc;
-
- ND_TCHECK_LEN(bp, VXLAN_GPE_HDR_LEN);
+ ND_PRINT("VXLAN-GPE, ");
+ if (len < VXLAN_GPE_HDR_LEN) {
+ ND_PRINT(" (len %u < %u)", len, VXLAN_GPE_HDR_LEN);
+ goto invalid;
+ }
flags = GET_U_1(bp);
- bp += 3;
+ bp += 1;
+ len -= 1;
+ ver = (flags & VXLAN_GPE_VER) >> VXLAN_GPE_SHIFT;
+ if (ver != VXLAN_GPE_VER_0) {
+ ND_PRINT("unknown version %u", ver);
+ goto invalid;
+ }
+ ND_PRINT("flags [%s], ",
+ bittok2str_nosep(vxlan_gpe_flags, "none", flags));
- next_protocol = GET_U_1(bp);
+ /* Reserved */
+ bp += 2;
+ len -= 2;
+
+ /*
+ * If the VXLAN_GPE_P flag bit isn't set, that means this is a VXLAN
+ * packet, not a VXLAN-GPE packet, and thus has no "next protocol"
+ * field; the payload is Ethernet.
+ */
+ if (flags & VXLAN_GPE_P)
+ next_protocol = GET_U_1(bp);
+ else
+ next_protocol = VXLAN_GPE_PROTO_ETHERNET;
bp += 1;
+ len -= 1;
+
+ /*
+ * Both RFC 7348 and draft-ietf-nvo3-vxlan-gpe-12 say that the I flag
+ * MUST be set.
+ */
+ if (flags & VXLAN_GPE_I)
+ ND_PRINT("vni %u", GET_BE_U_3(bp));
+ else
+ ND_PRINT("ERROR: I flag not set");
+ bp += 3;
+ len -= 3;
- vni = GET_BE_U_3(bp);
- bp += 4;
+ if (flags & VXLAN_GPE_B)
+ ND_PRINT(", BUM");
+
+ if (flags & VXLAN_GPE_O) {
+ ND_PRINT(", OAM (proto 0x%x, len %u)", next_protocol, len);
+ return;
+ }
+
+ /* Reserved */
+ ND_TCHECK_1(bp);
+ bp += 1;
+ len -= 1;
- ND_PRINT("VXLAN-GPE, ");
- ND_PRINT("flags [%s], ",
- bittok2str_nosep(vxlan_gpe_flags, "none", flags));
- ND_PRINT("vni %u", vni);
ND_PRINT(ndo->ndo_vflag ? "\n " : ": ");
switch (next_protocol) {
- case 0x1:
- ip_print(ndo, bp, len - VXLAN_GPE_HDR_LEN);
+ case VXLAN_GPE_PROTO_IPV4:
+ ip_print(ndo, bp, len);
break;
- case 0x2:
- ip6_print(ndo, bp, len - VXLAN_GPE_HDR_LEN);
+ case VXLAN_GPE_PROTO_IPV6:
+ ip6_print(ndo, bp, len);
break;
- case 0x3:
- ether_print(ndo, bp, len - VXLAN_GPE_HDR_LEN, ND_BYTES_AVAILABLE_AFTER(bp), NULL, NULL);
+ case VXLAN_GPE_PROTO_ETHERNET:
+ ether_print(ndo, bp, len, ND_BYTES_AVAILABLE_AFTER(bp), NULL, NULL);
break;
- case 0x4:
- nsh_print(ndo, bp, len - VXLAN_GPE_HDR_LEN);
- break;
- case 0x5:
- mpls_print(ndo, bp, len - VXLAN_GPE_HDR_LEN);
+ case VXLAN_GPE_PROTO_NSH:
+ nsh_print(ndo, bp, len);
break;
+ /*
+ * OpenBSD supports 0x05 for MPLS, which was in earlier drafts
+ * of VXLAN GPE, but not in the final -12 draft.
+ */
default:
ND_PRINT("ERROR: unknown-next-protocol");
- return;
+ goto invalid;
}
- return;
+ return;
-trunc:
- nd_print_trunc(ndo);
+invalid:
+ nd_print_invalid(ndo);
}
projects / tcpdump / blobdiff