/* * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that: (1) source code distributions * retain the above copyright notice and this paragraph in its entirety, (2) * distributions including binary code include the above copyright notice and * this paragraph in its entirety in the documentation or other materials * provided with the distribution, and (3) all advertising materials mentioning * features or use of this software display the following acknowledgement: * ``This product includes software developed by the University of California, * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of * the University nor the names of its contributors may be used to endorse * or promote products derived from this software without specific prior * written permission. * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. */ /* \summary: Domain Name System (DNS) printer */ #ifdef HAVE_CONFIG_H #include "config.h" #endif #include <netdissect-stdinc.h> #include "nameser.h" #include <string.h> #include "netdissect.h" #include "addrtoname.h" #include "addrtostr.h" #include "extract.h" static const char *ns_ops[] = { "", " inv_q", " stat", " op3", " notify", " update", " op6", " op7", " op8", " updateA", " updateD", " updateDA", " updateM", " updateMA", " zoneInit", " zoneRef", }; static const char *ns_resp[] = { "", " FormErr", " ServFail", " NXDomain", " NotImp", " Refused", " YXDomain", " YXRRSet", " NXRRSet", " NotAuth", " NotZone", " Resp11", " Resp12", " Resp13", " Resp14", " NoChange", }; /* skip over a domain name */ static const u_char * ns_nskip(netdissect_options *ndo, register const u_char *cp) { register u_char i; if (!ND_TTEST2(*cp, 1)) return (NULL); i = *cp++; while (i) { if ((i & INDIR_MASK) == INDIR_MASK) return (cp + 1); if ((i & INDIR_MASK) == EDNS0_MASK) { int bitlen, bytelen; if ((i & ~INDIR_MASK) != EDNS0_ELT_BITLABEL) return(NULL); /* unknown ELT */ if (!ND_TTEST2(*cp, 1)) return (NULL); if ((bitlen = *cp++) == 0) bitlen = 256; bytelen = (bitlen + 7) / 8; cp += bytelen; } else cp += i; if (!ND_TTEST2(*cp, 1)) return (NULL); i = *cp++; } return (cp); } /* print a <domain-name> */ static const u_char * blabel_print(netdissect_options *ndo, const u_char *cp) { int bitlen, slen, b; const u_char *bitp, *lim; char tc; if (!ND_TTEST2(*cp, 1)) return(NULL); if ((bitlen = *cp) == 0) bitlen = 256; slen = (bitlen + 3) / 4; lim = cp + 1 + slen; /* print the bit string as a hex string */ ND_PRINT((ndo, "\\[x")); for (bitp = cp + 1, b = bitlen; bitp < lim && b > 7; b -= 8, bitp++) { ND_TCHECK(*bitp); ND_PRINT((ndo, "%02x", *bitp)); } if (b > 4) { ND_TCHECK(*bitp); tc = *bitp++; ND_PRINT((ndo, "%02x", tc & (0xff << (8 - b)))); } else if (b > 0) { ND_TCHECK(*bitp); tc = *bitp++; ND_PRINT((ndo, "%1x", ((tc >> 4) & 0x0f) & (0x0f << (4 - b)))); } ND_PRINT((ndo, "/%d]", bitlen)); return lim; trunc: ND_PRINT((ndo, ".../%d]", bitlen)); return NULL; } static int labellen(netdissect_options *ndo, const u_char *cp) { register u_int i; if (!ND_TTEST2(*cp, 1)) return(-1); i = *cp; if ((i & INDIR_MASK) == EDNS0_MASK) { int bitlen, elt; if ((elt = (i & ~INDIR_MASK)) != EDNS0_ELT_BITLABEL) { ND_PRINT((ndo, "<ELT %d>", elt)); return(-1); } if (!ND_TTEST2(*(cp + 1), 1)) return(-1); if ((bitlen = *(cp + 1)) == 0) bitlen = 256; return(((bitlen + 7) / 8) + 1); } else return(i); } const u_char * ns_nprint(netdissect_options *ndo, register const u_char *cp, register const u_char *bp) { register u_int i, l; register const u_char *rp = NULL; register int compress = 0; int elt; u_int offset, max_offset; if ((l = labellen(ndo, cp)) == (u_int)-1) return(NULL); if (!ND_TTEST2(*cp, 1)) return(NULL); max_offset = (u_int)(cp - bp); if (((i = *cp++) & INDIR_MASK) != INDIR_MASK) { compress = 0; rp = cp + l; } if (i != 0) while (i && cp < ndo->ndo_snapend) { if ((i & INDIR_MASK) == INDIR_MASK) { if (!compress) { rp = cp + 1; compress = 1; } if (!ND_TTEST2(*cp, 1)) return(NULL); offset = (((i << 8) | *cp) & 0x3fff); /* * This must move backwards in the packet. * No RFC explicitly says that, but BIND's * name decompression code requires it, * as a way of preventing infinite loops * and other bad behavior, and it's probably * what was intended (compress by pointing * to domain name suffixes already seen in * the packet). */ if (offset >= max_offset) { ND_PRINT((ndo, "<BAD PTR>")); return(NULL); } max_offset = offset; cp = bp + offset; if ((l = labellen(ndo, cp)) == (u_int)-1) return(NULL); if (!ND_TTEST2(*cp, 1)) return(NULL); i = *cp++; continue; } if ((i & INDIR_MASK) == EDNS0_MASK) { elt = (i & ~INDIR_MASK); switch(elt) { case EDNS0_ELT_BITLABEL: if (blabel_print(ndo, cp) == NULL) return (NULL); break; default: /* unknown ELT */ ND_PRINT((ndo, "<ELT %d>", elt)); return(NULL); } } else { if (fn_printn(ndo, cp, l, ndo->ndo_snapend)) return(NULL); } cp += l; ND_PRINT((ndo, ".")); if ((l = labellen(ndo, cp)) == (u_int)-1) return(NULL); if (!ND_TTEST2(*cp, 1)) return(NULL); i = *cp++; if (!compress) rp += l + 1; } else ND_PRINT((ndo, ".")); return (rp); } /* print a <character-string> */ static const u_char * ns_cprint(netdissect_options *ndo, register const u_char *cp) { register u_int i; if (!ND_TTEST2(*cp, 1)) return (NULL); i = *cp++; if (fn_printn(ndo, cp, i, ndo->ndo_snapend)) return (NULL); return (cp + i); } /* http://www.iana.org/assignments/dns-parameters */ const struct tok ns_type2str[] = { { T_A, "A" }, /* RFC 1035 */ { T_NS, "NS" }, /* RFC 1035 */ { T_MD, "MD" }, /* RFC 1035 */ { T_MF, "MF" }, /* RFC 1035 */ { T_CNAME, "CNAME" }, /* RFC 1035 */ { T_SOA, "SOA" }, /* RFC 1035 */ { T_MB, "MB" }, /* RFC 1035 */ { T_MG, "MG" }, /* RFC 1035 */ { T_MR, "MR" }, /* RFC 1035 */ { T_NULL, "NULL" }, /* RFC 1035 */ { T_WKS, "WKS" }, /* RFC 1035 */ { T_PTR, "PTR" }, /* RFC 1035 */ { T_HINFO, "HINFO" }, /* RFC 1035 */ { T_MINFO, "MINFO" }, /* RFC 1035 */ { T_MX, "MX" }, /* RFC 1035 */ { T_TXT, "TXT" }, /* RFC 1035 */ { T_RP, "RP" }, /* RFC 1183 */ { T_AFSDB, "AFSDB" }, /* RFC 1183 */ { T_X25, "X25" }, /* RFC 1183 */ { T_ISDN, "ISDN" }, /* RFC 1183 */ { T_RT, "RT" }, /* RFC 1183 */ { T_NSAP, "NSAP" }, /* RFC 1706 */ { T_NSAP_PTR, "NSAP_PTR" }, { T_SIG, "SIG" }, /* RFC 2535 */ { T_KEY, "KEY" }, /* RFC 2535 */ { T_PX, "PX" }, /* RFC 2163 */ { T_GPOS, "GPOS" }, /* RFC 1712 */ { T_AAAA, "AAAA" }, /* RFC 1886 */ { T_LOC, "LOC" }, /* RFC 1876 */ { T_NXT, "NXT" }, /* RFC 2535 */ { T_EID, "EID" }, /* Nimrod */ { T_NIMLOC, "NIMLOC" }, /* Nimrod */ { T_SRV, "SRV" }, /* RFC 2782 */ { T_ATMA, "ATMA" }, /* ATM Forum */ { T_NAPTR, "NAPTR" }, /* RFC 2168, RFC 2915 */ { T_KX, "KX" }, /* RFC 2230 */ { T_CERT, "CERT" }, /* RFC 2538 */ { T_A6, "A6" }, /* RFC 2874 */ { T_DNAME, "DNAME" }, /* RFC 2672 */ { T_SINK, "SINK" }, { T_OPT, "OPT" }, /* RFC 2671 */ { T_APL, "APL" }, /* RFC 3123 */ { T_DS, "DS" }, /* RFC 4034 */ { T_SSHFP, "SSHFP" }, /* RFC 4255 */ { T_IPSECKEY, "IPSECKEY" }, /* RFC 4025 */ { T_RRSIG, "RRSIG" }, /* RFC 4034 */ { T_NSEC, "NSEC" }, /* RFC 4034 */ { T_DNSKEY, "DNSKEY" }, /* RFC 4034 */ { T_SPF, "SPF" }, /* RFC-schlitt-spf-classic-02.txt */ { T_UINFO, "UINFO" }, { T_UID, "UID" }, { T_GID, "GID" }, { T_UNSPEC, "UNSPEC" }, { T_UNSPECA, "UNSPECA" }, { T_TKEY, "TKEY" }, /* RFC 2930 */ { T_TSIG, "TSIG" }, /* RFC 2845 */ { T_IXFR, "IXFR" }, /* RFC 1995 */ { T_AXFR, "AXFR" }, /* RFC 1035 */ { T_MAILB, "MAILB" }, /* RFC 1035 */ { T_MAILA, "MAILA" }, /* RFC 1035 */ { T_ANY, "ANY" }, { 0, NULL } }; const struct tok ns_class2str[] = { { C_IN, "IN" }, /* Not used */ { C_CHAOS, "CHAOS" }, { C_HS, "HS" }, { C_ANY, "ANY" }, { 0, NULL } }; /* print a query */ static const u_char * ns_qprint(netdissect_options *ndo, register const u_char *cp, register const u_char *bp, int is_mdns) { register const u_char *np = cp; register u_int i, class; cp = ns_nskip(ndo, cp); if (cp == NULL || !ND_TTEST2(*cp, 4)) return(NULL); /* print the qtype */ i = EXTRACT_16BITS(cp); cp += 2; ND_PRINT((ndo, " %s", tok2str(ns_type2str, "Type%d", i))); /* print the qclass (if it's not IN) */ i = EXTRACT_16BITS(cp); cp += 2; if (is_mdns) class = (i & ~C_QU); else class = i; if (class != C_IN) ND_PRINT((ndo, " %s", tok2str(ns_class2str, "(Class %d)", class))); if (is_mdns) { ND_PRINT((ndo, i & C_QU ? " (QU)" : " (QM)")); } ND_PRINT((ndo, "? ")); cp = ns_nprint(ndo, np, bp); return(cp ? cp + 4 : NULL); } /* print a reply */ static const u_char * ns_rprint(netdissect_options *ndo, register const u_char *cp, register const u_char *bp, int is_mdns) { register u_int i, class, opt_flags = 0; register u_short typ, len; register const u_char *rp; if (ndo->ndo_vflag) { ND_PRINT((ndo, " ")); if ((cp = ns_nprint(ndo, cp, bp)) == NULL) return NULL; } else cp = ns_nskip(ndo, cp); if (cp == NULL || !ND_TTEST2(*cp, 10)) return (ndo->ndo_snapend); /* print the type/qtype */ typ = EXTRACT_16BITS(cp); cp += 2; /* print the class (if it's not IN and the type isn't OPT) */ i = EXTRACT_16BITS(cp); cp += 2; if (is_mdns) class = (i & ~C_CACHE_FLUSH); else class = i; if (class != C_IN && typ != T_OPT) ND_PRINT((ndo, " %s", tok2str(ns_class2str, "(Class %d)", class))); if (is_mdns) { if (i & C_CACHE_FLUSH) ND_PRINT((ndo, " (Cache flush)")); } if (typ == T_OPT) { /* get opt flags */ cp += 2; opt_flags = EXTRACT_16BITS(cp); /* ignore rest of ttl field */ cp += 2; } else if (ndo->ndo_vflag > 2) { /* print ttl */ ND_PRINT((ndo, " [")); unsigned_relts_print(ndo, EXTRACT_32BITS(cp)); ND_PRINT((ndo, "]")); cp += 4; } else { /* ignore ttl */ cp += 4; } len = EXTRACT_16BITS(cp); cp += 2; rp = cp + len; ND_PRINT((ndo, " %s", tok2str(ns_type2str, "Type%d", typ))); if (rp > ndo->ndo_snapend) return(NULL); switch (typ) { case T_A: if (!ND_TTEST2(*cp, sizeof(struct in_addr))) return(NULL); ND_PRINT((ndo, " %s", intoa(htonl(EXTRACT_32BITS(cp))))); break; case T_NS: case T_CNAME: case T_PTR: #ifdef T_DNAME case T_DNAME: #endif ND_PRINT((ndo, " ")); if (ns_nprint(ndo, cp, bp) == NULL) return(NULL); break; case T_SOA: if (!ndo->ndo_vflag) break; ND_PRINT((ndo, " ")); if ((cp = ns_nprint(ndo, cp, bp)) == NULL) return(NULL); ND_PRINT((ndo, " ")); if ((cp = ns_nprint(ndo, cp, bp)) == NULL) return(NULL); if (!ND_TTEST2(*cp, 5 * 4)) return(NULL); ND_PRINT((ndo, " %u", EXTRACT_32BITS(cp))); cp += 4; ND_PRINT((ndo, " %u", EXTRACT_32BITS(cp))); cp += 4; ND_PRINT((ndo, " %u", EXTRACT_32BITS(cp))); cp += 4; ND_PRINT((ndo, " %u", EXTRACT_32BITS(cp))); cp += 4; ND_PRINT((ndo, " %u", EXTRACT_32BITS(cp))); cp += 4; break; case T_MX: ND_PRINT((ndo, " ")); if (!ND_TTEST2(*cp, 2)) return(NULL); if (ns_nprint(ndo, cp + 2, bp) == NULL) return(NULL); ND_PRINT((ndo, " %d", EXTRACT_16BITS(cp))); break; case T_TXT: while (cp < rp) { ND_PRINT((ndo, " \"")); cp = ns_cprint(ndo, cp); if (cp == NULL) return(NULL); ND_PRINT((ndo, "\"")); } break; case T_SRV: ND_PRINT((ndo, " ")); if (!ND_TTEST2(*cp, 6)) return(NULL); if (ns_nprint(ndo, cp + 6, bp) == NULL) return(NULL); ND_PRINT((ndo, ":%d %d %d", EXTRACT_16BITS(cp + 4), EXTRACT_16BITS(cp), EXTRACT_16BITS(cp + 2))); break; case T_AAAA: { char ntop_buf[INET6_ADDRSTRLEN]; if (!ND_TTEST2(*cp, sizeof(struct in6_addr))) return(NULL); ND_PRINT((ndo, " %s", addrtostr6(cp, ntop_buf, sizeof(ntop_buf)))); break; } case T_A6: { struct in6_addr a; int pbit, pbyte; char ntop_buf[INET6_ADDRSTRLEN]; if (!ND_TTEST2(*cp, 1)) return(NULL); pbit = *cp; pbyte = (pbit & ~7) / 8; if (pbit > 128) { ND_PRINT((ndo, " %u(bad plen)", pbit)); break; } else if (pbit < 128) { if (!ND_TTEST2(*(cp + 1), sizeof(a) - pbyte)) return(NULL); memset(&a, 0, sizeof(a)); memcpy(&a.s6_addr[pbyte], cp + 1, sizeof(a) - pbyte); ND_PRINT((ndo, " %u %s", pbit, addrtostr6(&a, ntop_buf, sizeof(ntop_buf)))); } if (pbit > 0) { ND_PRINT((ndo, " ")); if (ns_nprint(ndo, cp + 1 + sizeof(a) - pbyte, bp) == NULL) return(NULL); } break; } case T_OPT: ND_PRINT((ndo, " UDPsize=%u", class)); if (opt_flags & 0x8000) ND_PRINT((ndo, " DO")); break; case T_UNSPECA: /* One long string */ if (!ND_TTEST2(*cp, len)) return(NULL); if (fn_printn(ndo, cp, len, ndo->ndo_snapend)) return(NULL); break; case T_TSIG: { if (cp + len > ndo->ndo_snapend) return(NULL); if (!ndo->ndo_vflag) break; ND_PRINT((ndo, " ")); if ((cp = ns_nprint(ndo, cp, bp)) == NULL) return(NULL); cp += 6; if (!ND_TTEST2(*cp, 2)) return(NULL); ND_PRINT((ndo, " fudge=%u", EXTRACT_16BITS(cp))); cp += 2; if (!ND_TTEST2(*cp, 2)) return(NULL); ND_PRINT((ndo, " maclen=%u", EXTRACT_16BITS(cp))); cp += 2 + EXTRACT_16BITS(cp); if (!ND_TTEST2(*cp, 2)) return(NULL); ND_PRINT((ndo, " origid=%u", EXTRACT_16BITS(cp))); cp += 2; if (!ND_TTEST2(*cp, 2)) return(NULL); ND_PRINT((ndo, " error=%u", EXTRACT_16BITS(cp))); cp += 2; if (!ND_TTEST2(*cp, 2)) return(NULL); ND_PRINT((ndo, " otherlen=%u", EXTRACT_16BITS(cp))); cp += 2; } } return (rp); /* XXX This isn't always right */ } void ns_print(netdissect_options *ndo, register const u_char *bp, u_int length, int is_mdns) { register const HEADER *np; register int qdcount, ancount, nscount, arcount; register const u_char *cp; uint16_t b2; np = (const HEADER *)bp; ND_TCHECK(*np); /* get the byte-order right */ qdcount = EXTRACT_16BITS(&np->qdcount); ancount = EXTRACT_16BITS(&np->ancount); nscount = EXTRACT_16BITS(&np->nscount); arcount = EXTRACT_16BITS(&np->arcount); if (DNS_QR(np)) { /* this is a response */ ND_PRINT((ndo, "%d%s%s%s%s%s%s", EXTRACT_16BITS(&np->id), ns_ops[DNS_OPCODE(np)], ns_resp[DNS_RCODE(np)], DNS_AA(np)? "*" : "", DNS_RA(np)? "" : "-", DNS_TC(np)? "|" : "", DNS_AD(np)? "$" : "")); if (qdcount != 1) ND_PRINT((ndo, " [%dq]", qdcount)); /* Print QUESTION section on -vv */ cp = (const u_char *)(np + 1); while (qdcount--) { if (qdcount < EXTRACT_16BITS(&np->qdcount) - 1) ND_PRINT((ndo, ",")); if (ndo->ndo_vflag > 1) { ND_PRINT((ndo, " q:")); if ((cp = ns_qprint(ndo, cp, bp, is_mdns)) == NULL) goto trunc; } else { if ((cp = ns_nskip(ndo, cp)) == NULL) goto trunc; cp += 4; /* skip QTYPE and QCLASS */ } } ND_PRINT((ndo, " %d/%d/%d", ancount, nscount, arcount)); if (ancount--) { if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL) goto trunc; while (cp < ndo->ndo_snapend && ancount--) { ND_PRINT((ndo, ",")); if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL) goto trunc; } } if (ancount > 0) goto trunc; /* Print NS and AR sections on -vv */ if (ndo->ndo_vflag > 1) { if (cp < ndo->ndo_snapend && nscount--) { ND_PRINT((ndo, " ns:")); if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL) goto trunc; while (cp < ndo->ndo_snapend && nscount--) { ND_PRINT((ndo, ",")); if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL) goto trunc; } } if (nscount > 0) goto trunc; if (cp < ndo->ndo_snapend && arcount--) { ND_PRINT((ndo, " ar:")); if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL) goto trunc; while (cp < ndo->ndo_snapend && arcount--) { ND_PRINT((ndo, ",")); if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL) goto trunc; } } if (arcount > 0) goto trunc; } } else { /* this is a request */ ND_PRINT((ndo, "%d%s%s%s", EXTRACT_16BITS(&np->id), ns_ops[DNS_OPCODE(np)], DNS_RD(np) ? "+" : "", DNS_CD(np) ? "%" : "")); /* any weirdness? */ b2 = EXTRACT_16BITS(((const u_short *)np)+1); if (b2 & 0x6cf) ND_PRINT((ndo, " [b2&3=0x%x]", b2)); if (DNS_OPCODE(np) == IQUERY) { if (qdcount) ND_PRINT((ndo, " [%dq]", qdcount)); if (ancount != 1) ND_PRINT((ndo, " [%da]", ancount)); } else { if (ancount) ND_PRINT((ndo, " [%da]", ancount)); if (qdcount != 1) ND_PRINT((ndo, " [%dq]", qdcount)); } if (nscount) ND_PRINT((ndo, " [%dn]", nscount)); if (arcount) ND_PRINT((ndo, " [%dau]", arcount)); cp = (const u_char *)(np + 1); if (qdcount--) { cp = ns_qprint(ndo, cp, (const u_char *)np, is_mdns); if (!cp) goto trunc; while (cp < ndo->ndo_snapend && qdcount--) { cp = ns_qprint(ndo, (const u_char *)cp, (const u_char *)np, is_mdns); if (!cp) goto trunc; } } if (qdcount > 0) goto trunc; /* Print remaining sections on -vv */ if (ndo->ndo_vflag > 1) { if (ancount--) { if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL) goto trunc; while (cp < ndo->ndo_snapend && ancount--) { ND_PRINT((ndo, ",")); if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL) goto trunc; } } if (ancount > 0) goto trunc; if (cp < ndo->ndo_snapend && nscount--) { ND_PRINT((ndo, " ns:")); if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL) goto trunc; while (nscount-- && cp < ndo->ndo_snapend) { ND_PRINT((ndo, ",")); if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL) goto trunc; } } if (nscount > 0) goto trunc; if (cp < ndo->ndo_snapend && arcount--) { ND_PRINT((ndo, " ar:")); if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL) goto trunc; while (cp < ndo->ndo_snapend && arcount--) { ND_PRINT((ndo, ",")); if ((cp = ns_rprint(ndo, cp, bp, is_mdns)) == NULL) goto trunc; } } if (arcount > 0) goto trunc; } } ND_PRINT((ndo, " (%d)", length)); return; trunc: ND_PRINT((ndo, "[|domain]")); }