X-Git-Url: https://git.tcpdump.org/tcpdump/blobdiff_plain/21480b97d89d0edebe1cb706503a9bee117bd9db..refs/heads/tcpdump-4.9:/print-mpls.c diff --git a/print-mpls.c b/print-mpls.c index c56f2643..5c26e4f9 100644 --- a/print-mpls.c +++ b/print-mpls.c @@ -26,38 +26,17 @@ * SUCH DAMAGE. */ -#ifndef lint -static const char rcsid[] _U_ = - "@(#) $Header: /tcpdump/master/tcpdump/print-mpls.c,v 1.11 2004-06-06 19:20:04 hannes Exp $ (LBL)"; -#endif +/* \summary: Multi-Protocol Label Switching (MPLS) printer */ #ifdef HAVE_CONFIG_H #include "config.h" #endif -#include - -#include -#include -#include - -#include "addrtoname.h" -#include "interface.h" -#include "extract.h" /* must come after interface.h */ - -#define LABEL_MASK 0xfffff000 -#define LABEL_SHIFT 12 -#define EXP_MASK 0x00000e00 -#define EXP_SHIFT 9 -#define STACK_MASK 0x00000100 -#define STACK_SHIFT 8 -#define TTL_MASK 0x000000ff -#define TTL_SHIFT 0 +#include -#define MPLS_LABEL(x) (((x) & LABEL_MASK) >> LABEL_SHIFT) -#define MPLS_EXP(x) (((x) & EXP_MASK) >> EXP_SHIFT) -#define MPLS_STACK(x) (((x) & STACK_MASK) >> STACK_SHIFT) -#define MPLS_TTL(x) (((x) & TTL_MASK) >> TTL_SHIFT) +#include "netdissect.h" +#include "extract.h" +#include "mpls.h" static const char *mpls_labelname[] = { /*0*/ "IPv4 explicit NULL", "router alert", "IPv6 explicit NULL", @@ -67,119 +46,177 @@ static const char *mpls_labelname[] = { /*15*/ "rsvd", }; +enum mpls_packet_type { + PT_UNKNOWN, + PT_IPV4, + PT_IPV6, + PT_OSI +}; + /* * RFC3032: MPLS label stack encoding */ void -mpls_print(const u_char *bp, u_int length) +mpls_print(netdissect_options *ndo, const u_char *bp, u_int length) { const u_char *p; - u_int32_t v; + uint32_t label_entry; + uint16_t label_stack_depth = 0; + enum mpls_packet_type pt = PT_UNKNOWN; p = bp; - printf("MPLS"); + ND_PRINT((ndo, "MPLS")); do { - TCHECK2(*p, sizeof(v)); - v = EXTRACT_32BITS(p); - printf(" ("); /*)*/ - printf("label %u", MPLS_LABEL(v)); - if (vflag && - MPLS_LABEL(v) < sizeof(mpls_labelname) / sizeof(mpls_labelname[0])) - printf(" (%s)", mpls_labelname[MPLS_LABEL(v)]); - printf(", exp %u", MPLS_EXP(v)); - if (MPLS_STACK(v)) - printf(", [S]"); - printf(", ttl %u", MPLS_TTL(v)); - /*(*/ - printf(")"); - - p += sizeof(v); - } while (!MPLS_STACK(v)); - - switch (MPLS_LABEL(v)) { + ND_TCHECK2(*p, sizeof(label_entry)); + if (length < sizeof(label_entry)) { + ND_PRINT((ndo, "[|MPLS], length %u", length)); + return; + } + label_entry = EXTRACT_32BITS(p); + ND_PRINT((ndo, "%s(label %u", + (label_stack_depth && ndo->ndo_vflag) ? "\n\t" : " ", + MPLS_LABEL(label_entry))); + label_stack_depth++; + if (ndo->ndo_vflag && + MPLS_LABEL(label_entry) < sizeof(mpls_labelname) / sizeof(mpls_labelname[0])) + ND_PRINT((ndo, " (%s)", mpls_labelname[MPLS_LABEL(label_entry)])); + ND_PRINT((ndo, ", exp %u", MPLS_EXP(label_entry))); + if (MPLS_STACK(label_entry)) + ND_PRINT((ndo, ", [S]")); + ND_PRINT((ndo, ", ttl %u)", MPLS_TTL(label_entry))); + + p += sizeof(label_entry); + length -= sizeof(label_entry); + } while (!MPLS_STACK(label_entry)); + + /* + * Try to figure out the packet type. + */ + switch (MPLS_LABEL(label_entry)) { + case 0: /* IPv4 explicit NULL label */ - case 3: /* IPv4 implicit NULL label */ - ip_print(p, length - (p - bp)); + case 3: /* IPv4 implicit NULL label */ + pt = PT_IPV4; break; -#ifdef INET6 + case 2: /* IPv6 explicit NULL label */ - ip6_print(p, length - (p - bp)); + pt = PT_IPV6; break; -#endif + default: /* * Generally there's no indication of protocol in MPLS label - * encoding, however draft-hsmit-isis-aal5mux-00.txt describes - * a technique that looks at the first payload byte if the BOS (bottom of stack) - * bit is set and tries to determine the network layer protocol - * 0x45-0x4f is IPv4 - * 0x60-0x6f is IPv6 - * 0x81-0x83 is OSI (CLNP,ES-IS,IS-IS) - * this technique is sometimes known as NULL encapsulation - * and decoding is particularly useful for control-plane traffic [BGP] - * which cisco by default sends MPLS encapsulated + * encoding. + * + * However, draft-hsmit-isis-aal5mux-00.txt describes a + * technique for encapsulating IS-IS and IP traffic on the + * same ATM virtual circuit; you look at the first payload + * byte to determine the network layer protocol, based on + * the fact that + * + * 1) the first byte of an IP header is 0x45-0x4f + * for IPv4 and 0x60-0x6f for IPv6; + * + * 2) the first byte of an OSI CLNP packet is 0x81, + * the first byte of an OSI ES-IS packet is 0x82, + * and the first byte of an OSI IS-IS packet is + * 0x83; + * + * so the network layer protocol can be inferred from the + * first byte of the packet, if the protocol is one of the + * ones listed above. + * + * Cisco sends control-plane traffic MPLS-encapsulated in + * this fashion. */ + ND_TCHECK(*p); + if (length < 1) { + /* nothing to print */ + return; + } + switch(*p) { - if (MPLS_STACK(v)) { /* only do this if the stack bit is set */ - switch(*p) { - case 0x45: - case 0x46: - case 0x47: - case 0x48: - case 0x49: - case 0x4a: - case 0x4b: - case 0x4c: - case 0x4d: - case 0x4e: - case 0x4f: - if (vflag>0) { - printf("\n\t"); - ip_print(p, length - (p - bp)); - } - else printf(", IP, length: %u",length); - break; -#ifdef INET6 - case 0x60: - case 0x61: - case 0x62: - case 0x63: - case 0x64: - case 0x65: - case 0x66: - case 0x67: - case 0x68: - case 0x69: - case 0x6a: - case 0x6b: - case 0x6c: - case 0x6d: - case 0x6e: - case 0x6f: - if (vflag>0) { - printf("\n\t"); - ip6_print(p, length - (p - bp)); - } - else printf(", IPv6, length: %u",length); - break; -#endif - case 0x81: - case 0x82: - case 0x83: - if (vflag>0) { - printf("\n\t"); - isoclns_print(p, length - (p - bp), length - (p - bp)); - } - else printf(", OSI, length: %u",length); - break; - default: - /* ok bail out - we did not figure out what it is*/ - break; - } - } - return; + case 0x45: + case 0x46: + case 0x47: + case 0x48: + case 0x49: + case 0x4a: + case 0x4b: + case 0x4c: + case 0x4d: + case 0x4e: + case 0x4f: + pt = PT_IPV4; + break; + + case 0x60: + case 0x61: + case 0x62: + case 0x63: + case 0x64: + case 0x65: + case 0x66: + case 0x67: + case 0x68: + case 0x69: + case 0x6a: + case 0x6b: + case 0x6c: + case 0x6d: + case 0x6e: + case 0x6f: + pt = PT_IPV6; + break; + + case 0x81: + case 0x82: + case 0x83: + pt = PT_OSI; + break; + + default: + /* ok bail out - we did not figure out what it is*/ + break; + } } + /* + * Print the payload. + */ + if (pt == PT_UNKNOWN) { + if (!ndo->ndo_suppress_default_print) + ND_DEFAULTPRINT(p, length); + return; + } + ND_PRINT((ndo, ndo->ndo_vflag ? "\n\t" : " ")); + switch (pt) { + + case PT_IPV4: + ip_print(ndo, p, length); + break; + + case PT_IPV6: + ip6_print(ndo, p, length); + break; + + case PT_OSI: + isoclns_print(ndo, p, length); + break; + + default: + break; + } + return; + trunc: - printf("[|MPLS]"); + ND_PRINT((ndo, "[|MPLS]")); } + + +/* + * Local Variables: + * c-style: whitesmith + * c-basic-offset: 8 + * End: + */