X-Git-Url: https://git.tcpdump.org/tcpdump/blobdiff_plain/a5830b4314e8723bfbf1f5f864f8f352671f7e15..HEAD:/print-vxlan-gpe.c diff --git a/print-vxlan-gpe.c b/print-vxlan-gpe.c index 336eb66d..2af9a65a 100644 --- a/print-vxlan-gpe.c +++ b/print-vxlan-gpe.c @@ -23,35 +23,48 @@ /* \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 -#include +#include "netdissect-stdinc.h" +#define ND_LONGJMP_FROM_TCHECK #include "netdissect.h" #include "extract.h" -static const char tstr[] = " [|VXLAN-GPE]"; +#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 | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ @@ -60,54 +73,106 @@ static const struct tok vxlan_gpe_flags [] = { 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; - if (len < VXLAN_GPE_HDR_LEN) - goto trunc; - - ND_TCHECK2(*bp, VXLAN_GPE_HDR_LEN); + /* + * 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"; + ND_PRINT("VXLAN-GPE, "); + if (len < VXLAN_GPE_HDR_LEN) { + ND_PRINT(" (len %u < %u)", len, VXLAN_GPE_HDR_LEN); + goto invalid; + } - flags = *bp; + flags = GET_U_1(bp); + 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)); + + /* 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; - next_protocol = *bp; - bp += 1; + if (flags & VXLAN_GPE_B) + ND_PRINT(", BUM"); - vni = EXTRACT_24BITS(bp); - bp += 4; + if (flags & VXLAN_GPE_O) { + ND_PRINT(", OAM (proto 0x%x, len %u)", next_protocol, len); + return; + } - ND_PRINT((ndo, "VXLAN-GPE, ")); - ND_PRINT((ndo, "flags [%s], ", - bittok2str_nosep(vxlan_gpe_flags, "none", flags))); - ND_PRINT((ndo, "vni %u", vni)); - ND_PRINT((ndo, ndo->ndo_vflag ? "\n " : ": ")); + /* Reserved */ + ND_TCHECK_1(bp); + bp += 1; + len -= 1; + + ND_PRINT(ndo->ndo_vflag ? "\n " : ": "); switch (next_protocol) { - case 0x1: - ip_print(ndo, bp, len - VXLAN_GPE_HDR_LEN); - break; - case 0x2: - ip6_print(ndo, bp, len - VXLAN_GPE_HDR_LEN); + case VXLAN_GPE_PROTO_IPV4: + ip_print(ndo, bp, len); break; - case 0x3: - ether_print(ndo, bp, len - VXLAN_GPE_HDR_LEN, ndo->ndo_snapend - bp, NULL, NULL); + case VXLAN_GPE_PROTO_IPV6: + ip6_print(ndo, bp, len); break; - case 0x4: - nsh_print(ndo, bp, len - VXLAN_GPE_HDR_LEN); + case VXLAN_GPE_PROTO_ETHERNET: + ether_print(ndo, bp, len, ND_BYTES_AVAILABLE_AFTER(bp), NULL, NULL); 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((ndo, "ERROR: unknown-next-protocol")); - return; + ND_PRINT("ERROR: unknown-next-protocol"); + goto invalid; } - return; + return; -trunc: - ND_PRINT((ndo, "%s", tstr)); +invalid: + nd_print_invalid(ndo); }