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-rw-r--r--src/dump_dns.c319
1 files changed, 319 insertions, 0 deletions
diff --git a/src/dump_dns.c b/src/dump_dns.c
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+++ b/src/dump_dns.c
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+/* dump_dns.c - library function to emit decoded dns message on a FILE.
+ *
+ * By: Paul Vixie, ISC, October 2007
+ */
+
+/*
+ * Copyright (c) 2016-2021, OARC, Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ *
+ * 3. Neither the name of the copyright holder 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 BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "config.h"
+
+#include "dnscap_common.h"
+
+#include "dump_dns.h"
+#include "network.h"
+#include "tcpstate.h"
+#include "endian_compat.h"
+
+#include <ldns/ldns.h>
+#include <netinet/in.h>
+
+static inline uint16_t _need16(const void* ptr)
+{
+ uint16_t v;
+ memcpy(&v, ptr, sizeof(v));
+ return be16toh(v);
+}
+
+static void dump_dns_rr(ldns_rr* rr, FILE* trace, ldns_buffer* lbuf, bool qsect)
+{
+ size_t rdlen, i;
+ ldns_rdf* rdf;
+
+ // owner
+ ldns_buffer_clear(lbuf);
+ if (ldns_rdf2buffer_str(lbuf, ldns_rr_owner(rr)) != LDNS_STATUS_OK) {
+ goto error;
+ }
+ fprintf(trace, "%s", (char*)ldns_buffer_begin(lbuf));
+
+ // class
+ ldns_buffer_clear(lbuf);
+ if (ldns_rr_class2buffer_str(lbuf, ldns_rr_get_class(rr)) != LDNS_STATUS_OK) {
+ goto error;
+ }
+ fprintf(trace, ",%s", (char*)ldns_buffer_begin(lbuf));
+
+ // type
+ ldns_buffer_clear(lbuf);
+ if (ldns_rr_type2buffer_str(lbuf, ldns_rr_get_type(rr)) != LDNS_STATUS_OK) {
+ goto error;
+ }
+ fprintf(trace, ",%s", (char*)ldns_buffer_begin(lbuf));
+
+ if (qsect)
+ return;
+
+ fprintf(trace, ",%u", ldns_rr_ttl(rr));
+ switch (ldns_rr_get_type(rr)) {
+ case LDNS_RR_TYPE_SOA:
+ for (i = 0; i < 2; i++) {
+ if (!(rdf = ldns_rr_rdf(rr, i))) {
+ goto error;
+ }
+ ldns_buffer_clear(lbuf);
+ if (ldns_rdf2buffer_str(lbuf, rdf) != LDNS_STATUS_OK) {
+ goto error;
+ }
+ fprintf(trace, ",%s", (char*)ldns_buffer_begin(lbuf));
+ }
+ for (; i < 7; i++) {
+ if (!(rdf = ldns_rr_rdf(rr, i))) {
+ goto error;
+ }
+ ldns_buffer_clear(lbuf);
+ if (ldns_rdf2buffer_str(lbuf, rdf) != LDNS_STATUS_OK) {
+ goto error;
+ }
+ fprintf(trace, ",%s", (char*)ldns_buffer_begin(lbuf));
+ }
+ break;
+
+ case LDNS_RR_TYPE_A:
+ case LDNS_RR_TYPE_AAAA:
+ case LDNS_RR_TYPE_MX:
+ if (!(rdf = ldns_rr_rdf(rr, 0))) {
+ goto error;
+ }
+ ldns_buffer_clear(lbuf);
+ if (ldns_rdf2buffer_str(lbuf, rdf) != LDNS_STATUS_OK) {
+ goto error;
+ }
+ fprintf(trace, ",%s", (char*)ldns_buffer_begin(lbuf));
+ break;
+
+ case LDNS_RR_TYPE_NS:
+ case LDNS_RR_TYPE_PTR:
+ case LDNS_RR_TYPE_CNAME:
+ if (!(rdf = ldns_rr_rdf(rr, 0))) {
+ goto error;
+ }
+ ldns_buffer_clear(lbuf);
+ if (ldns_rdf2buffer_str(lbuf, rdf) != LDNS_STATUS_OK) {
+ goto error;
+ }
+ fprintf(trace, ",%s", (char*)ldns_buffer_begin(lbuf));
+ break;
+
+ default:
+ goto error;
+ }
+ return;
+
+error:
+ for (rdlen = 0, i = 0, rdf = ldns_rr_rdf(rr, i); rdf; rdf = ldns_rr_rdf(rr, ++i)) {
+ rdlen += ldns_rdf_size(rdf);
+ }
+ fprintf(trace, ",[%zu]", rdlen);
+}
+
+static void dump_dns_sect(ldns_rr_list* rrs, FILE* trace, const char* endline, ldns_buffer* lbuf, bool qsect, bool ansect, ldns_pkt* pkt)
+{
+ size_t rrnum, rrmax;
+ const char* sep;
+
+ if (ansect && ldns_pkt_edns(pkt)) {
+ rrmax = ldns_rr_list_rr_count(rrs);
+ fprintf(trace, " %s%zu", endline, rrmax + 1);
+ sep = "";
+ for (rrnum = 0; rrnum < rrmax; rrnum++) {
+ fprintf(trace, " %s", sep);
+ dump_dns_rr(ldns_rr_list_rr(rrs, rrnum), trace, lbuf, qsect);
+ sep = endline;
+ }
+ ldns_rdf* edns_data = ldns_pkt_edns_data(pkt);
+ fprintf(trace, " %s.,%u,%u,0,edns0[len=%zu,UDP=%u,ver=%u,rcode=%u,DO=%u,z=%u]",
+ sep, ldns_pkt_edns_udp_size(pkt), ldns_pkt_edns_udp_size(pkt),
+ edns_data ? ldns_rdf_size(edns_data) : 0,
+ ldns_pkt_edns_udp_size(pkt),
+ ldns_pkt_edns_version(pkt),
+ ldns_pkt_edns_extended_rcode(pkt),
+ ldns_pkt_edns_do(pkt) ? 1 : 0,
+ ldns_pkt_edns_z(pkt));
+ if (edns_data) {
+ size_t len = ldns_rdf_size(edns_data);
+ uint8_t* d = ldns_rdf_data(edns_data);
+
+ while (len >= 4) {
+ uint16_t opcode = _need16(d);
+ uint16_t oplen = _need16(d + 2);
+ len -= 4;
+ d += 4;
+
+ if (oplen > len) {
+ break;
+ }
+ switch (opcode) {
+ case 8: {
+ if (oplen >= 4) {
+ uint16_t family = _need16(d);
+ uint8_t source_prefix_len = *(d + 2), scope_prefix_len = *(d + 3);
+ char addr[(INET_ADDRSTRLEN < INET6_ADDRSTRLEN ? INET6_ADDRSTRLEN : INET_ADDRSTRLEN) + 1] = { 0 };
+ struct in_addr in4 = { .s_addr = INADDR_ANY };
+ struct in6_addr in6 = IN6ADDR_ANY_INIT;
+ void* in = 0;
+ int af;
+
+ switch (family) {
+ case 1: {
+ memcpy(&in4.s_addr, d + 4, oplen - 4 > sizeof(in4.s_addr) ? sizeof(in4.s_addr) : oplen - 4);
+ in = &in4;
+ af = AF_INET;
+ break;
+ }
+ case 2: {
+ memcpy(&in6.s6_addr, d + 4, oplen - 4 > sizeof(in6.s6_addr) ? sizeof(in6.s6_addr) : oplen - 4);
+ in = &in6;
+ af = AF_INET6;
+ break;
+ }
+ default:
+ break;
+ }
+
+ fprintf(trace, ",edns0opt[ECS,family=%u,source=%u,scope=%u,", family, source_prefix_len, scope_prefix_len);
+
+ if (!in || !inet_ntop(af, in, addr, sizeof(addr) - 1)) {
+ fprintf(trace, "addr=INVALID]");
+ } else {
+ fprintf(trace, "addr=%s]", addr);
+ }
+
+ break;
+ }
+ }
+
+ default:
+ fprintf(trace, ",edns0opt[code=%u,codelen=%u]", opcode, oplen);
+ break;
+ }
+
+ len -= oplen;
+ d += oplen;
+ }
+ }
+ return;
+ }
+
+ rrmax = ldns_rr_list_rr_count(rrs);
+ if (rrmax == 0) {
+ fputs(" 0", trace);
+ return;
+ }
+ fprintf(trace, " %s%zu", endline, rrmax);
+ sep = "";
+ for (rrnum = 0; rrnum < rrmax; rrnum++) {
+ fprintf(trace, " %s", sep);
+ dump_dns_rr(ldns_rr_list_rr(rrs, rrnum), trace, lbuf, qsect);
+ sep = endline;
+ }
+}
+
+void dump_dns(const u_char* payload, size_t paylen, FILE* trace, const char* endline)
+{
+ const char* sep;
+ tcpstate_ptr tcpstate;
+ ldns_pkt* pkt = 0;
+ ldns_buffer* lbuf = 0;
+ ldns_status ret;
+
+ fprintf(trace, " %sdns ", endline);
+ if ((ret = ldns_wire2pkt(&pkt, payload, paylen)) != LDNS_STATUS_OK) {
+ /* DNS message may have padding, try get actual size */
+ size_t dnslen = calcdnslen(payload, paylen);
+ if (dnslen > 0 && dnslen < paylen) {
+ if ((ret = ldns_wire2pkt(&pkt, payload, dnslen)) != LDNS_STATUS_OK) {
+ fputs(ldns_get_errorstr_by_id(ret), trace);
+ if ((tcpstate = tcpstate_getcurr()))
+ tcpstate_reset(tcpstate, strerror(errno));
+ return;
+ }
+ } else {
+ fputs(ldns_get_errorstr_by_id(ret), trace);
+ if ((tcpstate = tcpstate_getcurr()))
+ tcpstate_reset(tcpstate, strerror(errno));
+ return;
+ }
+ }
+
+ if (!(lbuf = ldns_buffer_new(512))) {
+ fprintf(stderr, "%s: out of memory", ProgramName);
+ exit(1);
+ }
+
+ if (ldns_pkt_opcode2buffer_str(lbuf, ldns_pkt_get_opcode(pkt)) != LDNS_STATUS_OK) {
+ fprintf(stderr, "%s: unable to covert opcode to str", ProgramName);
+ exit(1);
+ }
+ fprintf(trace, "%s,", (char*)ldns_buffer_begin(lbuf));
+ ldns_buffer_clear(lbuf);
+ if (ldns_pkt_rcode2buffer_str(lbuf, ldns_pkt_get_rcode(pkt)) != LDNS_STATUS_OK) {
+ fprintf(stderr, "%s: unable to covert rcode to str", ProgramName);
+ exit(1);
+ }
+ fprintf(trace, "%s,%u,", (char*)ldns_buffer_begin(lbuf), ldns_pkt_id(pkt));
+
+ sep = "";
+#define FLAG(t, f) \
+ if (f) { \
+ fprintf(trace, "%s%s", sep, t); \
+ sep = "|"; \
+ }
+ FLAG("qr", ldns_pkt_qr(pkt));
+ FLAG("aa", ldns_pkt_aa(pkt));
+ FLAG("tc", ldns_pkt_tc(pkt));
+ FLAG("rd", ldns_pkt_rd(pkt));
+ FLAG("ra", ldns_pkt_ra(pkt));
+ FLAG("z", LDNS_Z_WIRE(payload));
+ FLAG("ad", ldns_pkt_ad(pkt));
+ FLAG("cd", ldns_pkt_cd(pkt));
+#undef FLAG
+ dump_dns_sect(ldns_pkt_question(pkt), trace, endline, lbuf, true, false, 0);
+ dump_dns_sect(ldns_pkt_answer(pkt), trace, endline, lbuf, false, false, 0);
+ dump_dns_sect(ldns_pkt_authority(pkt), trace, endline, lbuf, false, false, 0);
+ dump_dns_sect(ldns_pkt_additional(pkt), trace, endline, lbuf, false, true, pkt);
+
+ ldns_buffer_free(lbuf);
+ ldns_pkt_free(pkt);
+}
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