X-Git-Url: https://git.tcpdump.org/tcpdump/blobdiff_plain/c0937b0b98fa8451d2ee2281a7e2c384488b355e..47fc89d711eec0a073d9b3b293a1af901b5bd791:/print-icmp.c diff --git a/print-icmp.c b/print-icmp.c index 8b992d21..32357dfa 100644 --- a/print-icmp.c +++ b/print-icmp.c @@ -19,27 +19,14 @@ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. */ -#ifndef lint -static const char rcsid[] = - "@(#) $Header: /tcpdump/master/tcpdump/print-icmp.c,v 1.61 2001-07-19 19:37:31 itojun Exp $ (LBL)"; -#endif - #ifdef HAVE_CONFIG_H #include "config.h" #endif -#include -#include -#include - -struct mbuf; -struct rtentry; - -#include +#include #include #include -#include /* for MAXHOSTNAMELEN on some platforms */ #include "interface.h" #include "addrtoname.h" @@ -47,6 +34,8 @@ struct rtentry; #include "ip.h" #include "udp.h" +#include "ipproto.h" +#include "mpls.h" /* * Interface Control Message Protocol Definitions. @@ -68,20 +57,12 @@ struct icmp { u_int16_t icd_seq; } ih_idseq; u_int32_t ih_void; - - /* ICMP_UNREACH_NEEDFRAG -- Path MTU Discovery (RFC1191) */ - struct ih_pmtu { - u_int16_t ipm_void; - u_int16_t ipm_nextmtu; - } ih_pmtu; } icmp_hun; #define icmp_pptr icmp_hun.ih_pptr #define icmp_gwaddr icmp_hun.ih_gwaddr #define icmp_id icmp_hun.ih_idseq.icd_id #define icmp_seq icmp_hun.ih_idseq.icd_seq #define icmp_void icmp_hun.ih_void -#define icmp_pmvoid icmp_hun.ih_pmtu.ipm_void -#define icmp_nextmtu icmp_hun.ih_pmtu.ipm_nextmtu union { struct id_ts { u_int32_t its_otime; @@ -103,6 +84,9 @@ struct icmp { #define icmp_data icmp_dun.id_data }; +#define ICMP_MPLS_EXT_EXTRACT_VERSION(x) (((x)&0xf0)>>4) +#define ICMP_MPLS_EXT_VERSION 2 + /* * Lower bounds on packet lengths for various types. * For the error advice packets must first insure that the @@ -112,6 +96,7 @@ struct icmp { * ip header length. */ #define ICMP_MINLEN 8 /* abs minimum */ +#define ICMP_EXTD_MINLEN (156 - sizeof (struct ip)) /* draft-bonica-internet-icmp-08 */ #define ICMP_TSLEN (8 + 3 * sizeof (u_int32_t)) /* timestamp */ #define ICMP_MASKLEN 12 /* address mask */ #define ICMP_ADVLENMIN (8 + sizeof (struct ip) + 8) /* min */ @@ -165,6 +150,10 @@ struct icmp { (type) == ICMP_TSTAMP || (type) == ICMP_TSTAMPREPLY || \ (type) == ICMP_IREQ || (type) == ICMP_IREQREPLY || \ (type) == ICMP_MASKREQ || (type) == ICMP_MASKREPLY) +#define ICMP_MPLS_EXT_TYPE(type) \ + ((type) == ICMP_UNREACH || \ + (type) == ICMP_TIMXCEED || \ + (type) == ICMP_PARAMPROB) /* rfc1700 */ #ifndef ICMP_UNREACH_NET_UNKNOWN #define ICMP_UNREACH_NET_UNKNOWN 6 /* destination net unknown */ @@ -200,7 +189,7 @@ struct icmp { #endif /* Most of the icmp types */ -static struct tok icmp2str[] = { +static const struct tok icmp2str[] = { { ICMP_ECHOREPLY, "echo reply" }, { ICMP_SOURCEQUENCH, "source quench" }, { ICMP_ECHO, "echo request" }, @@ -214,7 +203,7 @@ static struct tok icmp2str[] = { }; /* Formats for most of the ICMP_UNREACH codes */ -static struct tok unreach2str[] = { +static const struct tok unreach2str[] = { { ICMP_UNREACH_NET, "net %s unreachable" }, { ICMP_UNREACH_HOST, "host %s unreachable" }, { ICMP_UNREACH_SRCFAIL, @@ -241,11 +230,11 @@ static struct tok unreach2str[] = { }; /* Formats for the ICMP_REDIRECT codes */ -static struct tok type2str[] = { +static const struct tok type2str[] = { { ICMP_REDIRECT_NET, "redirect %s to net %s" }, { ICMP_REDIRECT_HOST, "redirect %s to host %s" }, { ICMP_REDIRECT_TOSNET, "redirect-tos %s to net %s" }, - { ICMP_REDIRECT_TOSHOST, "redirect-tos %s to net %s" }, + { ICMP_REDIRECT_TOSHOST, "redirect-tos %s to host %s" }, { 0, NULL } }; @@ -267,25 +256,111 @@ struct id_rdiscovery { u_int32_t ird_pref; }; +/* + * draft-bonica-internet-icmp-08 + * + * The Destination Unreachable, Time Exceeded + * and Parameter Problem messages are slighly changed as per + * the above draft. A new Length field gets added to give + * the caller an idea about the length of the piggypacked + * IP packet before the MPLS extension header starts. + * + * The Length field represents length of the padded "original datagram" + * field measured in 32-bit words. + * + * 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 + * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + * | Type | Code | Checksum | + * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + * | unused | Length | unused | + * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + * | Internet Header + leading octets of original datagram | + * | | + * | // | + * | | + * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + */ + +struct icmp_ext_t { + u_int8_t icmp_type; + u_int8_t icmp_code; + u_int8_t icmp_checksum[2]; + u_int8_t icmp_reserved; + u_int8_t icmp_length; + u_int8_t icmp_reserved2[2]; + u_int8_t icmp_ext_legacy_header[128]; /* extension header starts 128 bytes after ICMP header */ + u_int8_t icmp_ext_version_res[2]; + u_int8_t icmp_ext_checksum[2]; + u_int8_t icmp_ext_data[1]; +}; + +struct icmp_mpls_ext_object_header_t { + u_int8_t length[2]; + u_int8_t class_num; + u_int8_t ctype; +}; + +static const struct tok icmp_mpls_ext_obj_values[] = { + { 1, "MPLS Stack Entry" }, + { 2, "Extended Payload" }, + { 0, NULL} +}; + +/* prototypes */ +const char *icmp_tstamp_print(u_int); + +/* print the milliseconds since midnight UTC */ +const char * +icmp_tstamp_print(u_int tstamp) { + u_int msec,sec,min,hrs; + + static char buf[64]; + + msec = tstamp % 1000; + sec = tstamp / 1000; + min = sec / 60; sec -= min * 60; + hrs = min / 60; min -= hrs * 60; + snprintf(buf, sizeof(buf), "%02u:%02u:%02u.%03u",hrs,min,sec,msec); + return buf; +} + void -icmp_print(const u_char *bp, u_int plen, const u_char *bp2) +icmp_print(const u_char *bp, u_int plen, const u_char *bp2, int fragmented) { char *cp; const struct icmp *dp; + const struct icmp_ext_t *ext_dp; const struct ip *ip; const char *str, *fmt; const struct ip *oip; const struct udphdr *ouh; - u_int hlen, dport, mtu; + const u_int8_t *obj_tptr; + u_int32_t raw_label; + const u_char *snapend_save; + const struct icmp_mpls_ext_object_header_t *icmp_mpls_ext_object_header; + u_int hlen, dport, mtu, obj_tlen, obj_class_num, obj_ctype; char buf[MAXHOSTNAMELEN + 100]; + struct cksum_vec vec[1]; dp = (struct icmp *)bp; + ext_dp = (struct icmp_ext_t *)bp; ip = (struct ip *)bp2; str = buf; TCHECK(dp->icmp_code); switch (dp->icmp_type) { + case ICMP_ECHO: + case ICMP_ECHOREPLY: + TCHECK(dp->icmp_seq); + (void)snprintf(buf, sizeof(buf), "echo %s, id %u, seq %u", + dp->icmp_type == ICMP_ECHO ? + "request" : "reply", + EXTRACT_16BITS(&dp->icmp_id), + EXTRACT_16BITS(&dp->icmp_seq)); + break; + case ICMP_UNREACH: TCHECK(dp->icmp_ip.ip_dst); switch (dp->icmp_code) { @@ -303,7 +378,8 @@ icmp_print(const u_char *bp, u_int plen, const u_char *bp2) oip = &dp->icmp_ip; hlen = IP_HL(oip) * 4; ouh = (struct udphdr *)(((u_char *)oip) + hlen); - dport = ntohs(ouh->uh_dport); + TCHECK(ouh->uh_dport); + dport = EXTRACT_16BITS(&ouh->uh_dport); switch (oip->ip_p) { case IPPROTO_TCP: @@ -332,7 +408,7 @@ icmp_print(const u_char *bp, u_int plen, const u_char *bp2) case ICMP_UNREACH_NEEDFRAG: { register const struct mtu_discovery *mp; - mp = (struct mtu_discovery *)&dp->icmp_void; + mp = (struct mtu_discovery *)(u_char *)&dp->icmp_void; mtu = EXTRACT_16BITS(&mp->nexthopmtu); if (mtu) { (void)snprintf(buf, sizeof(buf), @@ -448,47 +524,173 @@ icmp_print(const u_char *bp, u_int plen, const u_char *bp2) case ICMP_MASKREPLY: TCHECK(dp->icmp_mask); (void)snprintf(buf, sizeof(buf), "address mask is 0x%08x", - (unsigned)ntohl(dp->icmp_mask)); + EXTRACT_32BITS(&dp->icmp_mask)); break; case ICMP_TSTAMP: TCHECK(dp->icmp_seq); (void)snprintf(buf, sizeof(buf), "time stamp query id %u seq %u", - (unsigned)ntohs(dp->icmp_id), - (unsigned)ntohs(dp->icmp_seq)); + EXTRACT_16BITS(&dp->icmp_id), + EXTRACT_16BITS(&dp->icmp_seq)); break; case ICMP_TSTAMPREPLY: TCHECK(dp->icmp_ttime); (void)snprintf(buf, sizeof(buf), - "time stamp reply id %u seq %u : org 0x%lx recv 0x%lx xmit 0x%lx", - (unsigned)ntohs(dp->icmp_id), - (unsigned)ntohs(dp->icmp_seq), - (unsigned long)ntohl(dp->icmp_otime), - (unsigned long)ntohl(dp->icmp_rtime), - (unsigned long)ntohl(dp->icmp_ttime)); - break; + "time stamp reply id %u seq %u: org %s", + EXTRACT_16BITS(&dp->icmp_id), + EXTRACT_16BITS(&dp->icmp_seq), + icmp_tstamp_print(EXTRACT_32BITS(&dp->icmp_otime))); + + (void)snprintf(buf+strlen(buf),sizeof(buf)-strlen(buf),", recv %s", + icmp_tstamp_print(EXTRACT_32BITS(&dp->icmp_rtime))); + (void)snprintf(buf+strlen(buf),sizeof(buf)-strlen(buf),", xmit %s", + icmp_tstamp_print(EXTRACT_32BITS(&dp->icmp_ttime))); + break; default: str = tok2str(icmp2str, "type-#%d", dp->icmp_type); break; } - (void)printf("icmp: %s", str); - if (vflag) { + (void)printf("ICMP %s, length %u", str, plen); + if (vflag && !fragmented) { /* don't attempt checksumming if this is a frag */ + u_int16_t sum, icmp_sum; + struct cksum_vec vec[1]; if (TTEST2(*bp, plen)) { - if (in_cksum((u_short*)dp, plen, 0)) - printf(" (wrong icmp csum)"); + vec[0].ptr = (const u_int8_t *)(void *)dp; + vec[0].len = plen; + sum = in_cksum(vec, 1); + if (sum != 0) { + icmp_sum = EXTRACT_16BITS(&dp->icmp_cksum); + (void)printf(" (wrong icmp cksum %x (->%x)!)", + icmp_sum, + in_cksum_shouldbe(icmp_sum, sum)); + } } } - if (vflag > 1 && !ICMP_INFOTYPE(dp->icmp_type)) { - bp += 8; - (void)printf(" for "); - ip = (struct ip *)bp; - snaplen = snapend - bp; - ip_print(bp, ntohs(ip->ip_len)); - } + + /* + * print the remnants of the IP packet. + * save the snaplength as this may get overidden in the IP printer. + */ + if (vflag >= 1 && !ICMP_INFOTYPE(dp->icmp_type)) { + bp += 8; + (void)printf("\n\t"); + ip = (struct ip *)bp; + snaplen = snapend - bp; + snapend_save = snapend; + ip_print(gndo, bp, EXTRACT_16BITS(&ip->ip_len)); + snapend = snapend_save; + } + + /* + * Attempt to decode the MPLS extensions only for some ICMP types. + */ + if (vflag >= 1 && plen > ICMP_EXTD_MINLEN && ICMP_MPLS_EXT_TYPE(dp->icmp_type)) { + + TCHECK(*ext_dp); + + /* + * Check first if the mpls extension header shows a non-zero length. + * If the length field is not set then silently verify the checksum + * to check if an extension header is present. This is expedient, + * however not all implementations set the length field proper. + */ + if (!ext_dp->icmp_length) { + vec[0].ptr = (const u_int8_t *)(void *)&ext_dp->icmp_ext_version_res; + vec[0].len = plen - ICMP_EXTD_MINLEN; + if (in_cksum(vec, 1)) { + return; + } + } + + printf("\n\tMPLS extension v%u", + ICMP_MPLS_EXT_EXTRACT_VERSION(*(ext_dp->icmp_ext_version_res))); + + /* + * Sanity checking of the header. + */ + if (ICMP_MPLS_EXT_EXTRACT_VERSION(*(ext_dp->icmp_ext_version_res)) != + ICMP_MPLS_EXT_VERSION) { + printf(" packet not supported"); + return; + } + + hlen = plen - ICMP_EXTD_MINLEN; + vec[0].ptr = (const u_int8_t *)(void *)&ext_dp->icmp_ext_version_res; + vec[0].len = hlen; + printf(", checksum 0x%04x (%scorrect), length %u", + EXTRACT_16BITS(ext_dp->icmp_ext_checksum), + in_cksum(vec, 1) ? "in" : "", + hlen); + + hlen -= 4; /* subtract common header size */ + obj_tptr = (u_int8_t *)ext_dp->icmp_ext_data; + + while (hlen > sizeof(struct icmp_mpls_ext_object_header_t)) { + + icmp_mpls_ext_object_header = (struct icmp_mpls_ext_object_header_t *)obj_tptr; + TCHECK(*icmp_mpls_ext_object_header); + obj_tlen = EXTRACT_16BITS(icmp_mpls_ext_object_header->length); + obj_class_num = icmp_mpls_ext_object_header->class_num; + obj_ctype = icmp_mpls_ext_object_header->ctype; + obj_tptr += sizeof(struct icmp_mpls_ext_object_header_t); + + printf("\n\t %s Object (%u), Class-Type: %u, length %u", + tok2str(icmp_mpls_ext_obj_values,"unknown",obj_class_num), + obj_class_num, + obj_ctype, + obj_tlen); + + hlen-=sizeof(struct icmp_mpls_ext_object_header_t); /* length field includes tlv header */ + + /* infinite loop protection */ + if ((obj_class_num == 0) || + (obj_tlen < sizeof(struct icmp_mpls_ext_object_header_t))) { + return; + } + obj_tlen-=sizeof(struct icmp_mpls_ext_object_header_t); + + switch (obj_class_num) { + case 1: + switch(obj_ctype) { + case 1: + TCHECK2(*obj_tptr, 4); + raw_label = EXTRACT_32BITS(obj_tptr); + printf("\n\t label %u, exp %u", MPLS_LABEL(raw_label), MPLS_EXP(raw_label)); + if (MPLS_STACK(raw_label)) + printf(", [S]"); + printf(", ttl %u", MPLS_TTL(raw_label)); + break; + default: + print_unknown_data(gndo,obj_tptr, "\n\t ", obj_tlen); + } + break; + + /* + * FIXME those are the defined objects that lack a decoder + * you are welcome to contribute code ;-) + */ + case 2: + default: + print_unknown_data(gndo,obj_tptr, "\n\t ", obj_tlen); + break; + } + if (hlen < obj_tlen) + break; + hlen -= obj_tlen; + obj_tptr += obj_tlen; + } + } + return; trunc: fputs("[|icmp]", stdout); } +/* + * Local Variables: + * c-style: whitesmith + * c-basic-offset: 8 + * End: + */