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-rw-r--r--plugins/eventlog/eventlog.c425
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diff --git a/plugins/eventlog/eventlog.c b/plugins/eventlog/eventlog.c
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+/* eventlog.c
+ *
+ * Byron Darrah - May 20, 2020
+ * Version 1.0
+ *
+ * This is a plugin for dnscap, based on the txtout plugin.
+ *
+ * This plugin generates one line of output for each packet, with a human-
+ * readable timestamp, and includes the results of A and AAAA queries (which
+ * is either a list of IP addresses, or an NXDOMAIN flag).
+ *
+ * Below is the original copyright notice from txtout.c.
+ */
+/*
+ * 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 <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <netinet/in.h>
+#include <ctype.h>
+#include <errno.h>
+#include <arpa/inet.h>
+#include <arpa/nameser.h>
+#include <ldns/ldns.h>
+
+#include "dnscap_common.h"
+
+static logerr_t* logerr;
+static char* opt_o = NULL;
+static int opt_s = 0;
+static FILE* out = 0;
+static int opt_t = 0;
+static char* opt_n = NULL;
+
+output_t eventlog_output;
+
+void eventlog_usage()
+{
+ fprintf(stderr,
+ "\neventlog.so options:\n"
+ " -? print these instructions and exit\n"
+ " -o <arg> output file name\n"
+ " -s short output, only QTYPE/QNAME for IN\n"
+ " -t prefix event messages with DNS packet timestamp\n"
+ " -n <arg> include name with each event message\n\n"
+ "Produces a line of text per packet suitable for event logging,\n"
+ "including IP addresses from query responses.\n");
+}
+
+void eventlog_getopt(int* argc, char** argv[])
+{
+ /*
+ * The "getopt" function will be called from the parent to
+ * process plugin options.
+ */
+ int c;
+ while ((c = getopt(*argc, *argv, "?so:tn:")) != EOF) {
+ switch (c) {
+ case 'o':
+ if (opt_o)
+ free(opt_o);
+ opt_o = strdup(optarg);
+ break;
+ case 's':
+ opt_s = 1;
+ break;
+ case 't':
+ opt_t = 1;
+ break;
+ case 'n':
+ opt_n = strdup(optarg);
+ break;
+ case '?':
+ eventlog_usage();
+ if (!optopt || optopt == '?') {
+ exit(0);
+ }
+ // fallthrough
+ default:
+ exit(1);
+ }
+ }
+}
+
+int eventlog_start(logerr_t* a_logerr)
+{
+ /*
+ * The "start" function is called once, when the program
+ * starts. It is used to initialize the plugin. If the
+ * plugin wants to write debugging and or error messages,
+ * it should save the a_logerr pointer passed from the
+ * parent code.
+ */
+ logerr = a_logerr;
+ if (opt_o) {
+ out = fopen(opt_o, "a");
+ if (0 == out) {
+ logerr("%s: %s\n", opt_o, strerror(errno));
+ exit(1);
+ }
+ } else {
+ out = stdout;
+ }
+ setbuf(out, 0);
+
+ if (opt_t) {
+ time_t curtime;
+ char time_text[25];
+ struct tm res;
+ curtime = time(NULL);
+ if (strftime(time_text, 25, "%G %m/%d %T", localtime_r(&curtime, &res)) > 0) {
+ fprintf(out, "%s ", time_text);
+ } else {
+ fprintf(out, "**ERROR reading time** ");
+ }
+ }
+ if (opt_n) {
+ fprintf(out, "%s ", opt_n);
+ }
+ fprintf(out, "DNS event logging started.\n");
+
+ return 0;
+}
+
+void eventlog_stop()
+{
+ /*
+ * The "start" function is called once, when the program
+ * is exiting normally. It might be used to clean up state,
+ * free memory, etc.
+ */
+ if (out != stdout)
+ fclose(out);
+}
+
+int eventlog_open(my_bpftimeval ts)
+{
+ /*
+ * The "open" function is called at the start of each
+ * collection interval, which might be based on a period
+ * of time or a number of packets. In the original code,
+ * this is where we opened an output pcap file.
+ */
+ return 0;
+}
+
+int eventlog_close(my_bpftimeval ts)
+{
+ /*
+ * The "close" function is called at the end of each
+ * collection interval, which might be based on a period
+ * of time or on a number of packets. In the original code
+ * this is where we closed an output pcap file.
+ */
+ return 0;
+}
+
+ia_str_t ia_str = 0;
+tcpstate_getcurr_t tcpstate_getcurr = 0;
+tcpstate_reset_t tcpstate_reset = 0;
+
+void eventlog_extension(int ext, void* arg)
+{
+ switch (ext) {
+ case DNSCAP_EXT_IA_STR:
+ ia_str = (ia_str_t)arg;
+ break;
+ case DNSCAP_EXT_TCPSTATE_GETCURR:
+ tcpstate_getcurr = (tcpstate_getcurr_t)arg;
+ break;
+ case DNSCAP_EXT_TCPSTATE_RESET:
+ tcpstate_reset = (tcpstate_reset_t)arg;
+ break;
+ }
+}
+
+static void eventlog_output_ipbytes(size_t len, const uint8_t* data)
+{
+
+ /* If there are 4 bytes, print them as an IPv4 address. */
+ if (len == 4) {
+ fprintf(out, "%u.%u.%u.%u", data[0], data[1], data[2], data[3]);
+ }
+
+ /* If there are 16 bytes, print them as an IPv6 address. */
+ else if (len == 16) {
+ /* If there are 16 bytes, print them as an IPv6 address. */
+ fprintf(out, "%x:%x:%x:%x:%x:%x:%x:%x",
+ ((unsigned int)data[0]) << 8 | data[1],
+ ((unsigned int)data[2]) << 8 | data[3],
+ ((unsigned int)data[4]) << 8 | data[5],
+ ((unsigned int)data[6]) << 8 | data[7],
+ ((unsigned int)data[8]) << 8 | data[9],
+ ((unsigned int)data[10]) << 8 | data[11],
+ ((unsigned int)data[12]) << 8 | data[13],
+ ((unsigned int)data[14]) << 8 | data[15]);
+ }
+}
+
+void eventlog_output(const char* descr, iaddr from, iaddr to, uint8_t proto, unsigned flags,
+ unsigned sport, unsigned dport, my_bpftimeval ts,
+ const u_char* pkt_copy, unsigned olen,
+ const u_char* payload, unsigned payloadlen)
+{
+
+ /* Do not output anything if there is no DNS info to report. */
+ if (!(flags & DNSCAP_OUTPUT_ISDNS)) {
+ return;
+ }
+ ldns_pkt* pkt;
+ if (ldns_wire2pkt(&pkt, payload, payloadlen) != LDNS_STATUS_OK) {
+ if (tcpstate_getcurr && tcpstate_reset)
+ tcpstate_reset(tcpstate_getcurr(), "");
+ return;
+ }
+ ldns_buffer* buf = ldns_buffer_new(512);
+ if (!buf) {
+ logerr("out of memmory\n");
+ exit(1);
+ }
+
+ /*
+ * Output the packet timestamp
+ */
+ if (opt_t) {
+ char time_text[25];
+ struct tm res;
+ if (strftime(time_text, 25, "%G %m/%d %T", localtime_r(&ts.tv_sec, &res)) > 0) {
+ fprintf(out, "%s ", time_text);
+ } else {
+ fprintf(out, "**ERROR reading packet time** ");
+ }
+ }
+ if (opt_n) {
+ fprintf(out, "%s ", opt_n);
+ }
+
+ /*
+ * Short output, only print QTYPE and QNAME for IN records
+ */
+ if (opt_s) {
+ ldns_rr_list* qds = ldns_pkt_question(pkt);
+ if (qds) {
+ ldns_rr* qd = ldns_rr_list_rr(qds, 0);
+
+ if (qd && ldns_rr_get_class(qd) == LDNS_RR_CLASS_IN) {
+ if (ldns_rr_type2buffer_str(buf, ldns_rr_get_type(qd)) == LDNS_STATUS_OK) {
+ fprintf(out, "%s", (char*)ldns_buffer_begin(buf));
+ } else {
+ fprintf(out, "ERR");
+ }
+
+ ldns_buffer_clear(buf);
+ if (ldns_rdf2buffer_str(buf, ldns_rr_owner(qd)) == LDNS_STATUS_OK) {
+ fprintf(out, " %s\n", (char*)ldns_buffer_begin(buf));
+ } else {
+ fprintf(out, "ERR\n");
+ }
+ }
+ }
+ ldns_pkt_free(pkt);
+ ldns_buffer_free(buf);
+ return;
+ }
+
+ /*
+ * IP Stuff
+ */
+ fprintf(out, "src=%s spt=%u ", ia_str(from), sport);
+ fprintf(out, "dst=%s dpt=%u ", ia_str(to), dport);
+ switch (proto) {
+ case 17:
+ fprintf(out, "proto=UDP");
+ break;
+ case 6:
+ fprintf(out, "proto=TCP");
+ break;
+ default:
+ fprintf(out, "proto=%hhu", proto);
+ break;
+ }
+
+ /*
+ * DNS Header
+ */
+ fprintf(out, " mid=%u", ldns_pkt_id(pkt));
+ fprintf(out, " op=%u", ldns_pkt_get_opcode(pkt));
+ fprintf(out, " fl=|");
+ if (ldns_pkt_qr(pkt))
+ fprintf(out, "QR|");
+ if (ldns_pkt_aa(pkt))
+ fprintf(out, "AA|");
+ if (ldns_pkt_tc(pkt))
+ fprintf(out, "TC|");
+ if (ldns_pkt_rd(pkt))
+ fprintf(out, "RD|");
+ if (ldns_pkt_ra(pkt))
+ fprintf(out, "RA|");
+ if (ldns_pkt_ad(pkt))
+ fprintf(out, "AD|");
+ if (ldns_pkt_cd(pkt))
+ fprintf(out, "CD|");
+ switch (ldns_pkt_get_rcode(pkt)) {
+ case LDNS_RCODE_NOERROR:
+ fprintf(out, " rc=OK");
+ break;
+ case LDNS_RCODE_NXDOMAIN:
+ fprintf(out, " rc=NXDOMAIN");
+ break;
+ case LDNS_RCODE_SERVFAIL:
+ fprintf(out, " rc=SRVFAIL");
+ break;
+ default:
+ fprintf(out, " rc=%u", ldns_pkt_get_rcode(pkt));
+ break;
+ }
+
+ ldns_rr_list* qds = ldns_pkt_question(pkt);
+ ldns_rr* qd;
+ if (qds && (qd = ldns_rr_list_rr(qds, 0))) {
+ if (ldns_rr_class2buffer_str(buf, ldns_rr_get_class(qd)) == LDNS_STATUS_OK) {
+ fprintf(out, " cl=%s", (char*)ldns_buffer_begin(buf));
+ } else {
+ fprintf(out, " **ERROR parsing response record**\n");
+ ldns_pkt_free(pkt);
+ ldns_buffer_free(buf);
+ return;
+ }
+
+ ldns_buffer_clear(buf);
+ if (ldns_rr_type2buffer_str(buf, ldns_rr_get_type(qd)) == LDNS_STATUS_OK) {
+ fprintf(out, " tp=%s", (char*)ldns_buffer_begin(buf));
+ } else {
+ fprintf(out, " **ERROR parsing response record**\n");
+ ldns_pkt_free(pkt);
+ ldns_buffer_free(buf);
+ return;
+ }
+
+ ldns_buffer_clear(buf);
+ if (ldns_rdf2buffer_str(buf, ldns_rr_owner(qd)) == LDNS_STATUS_OK) {
+ fprintf(out, " name=%s\n", (char*)ldns_buffer_begin(buf));
+ } else {
+ fprintf(out, " **ERROR parsing response record**\n");
+ ldns_pkt_free(pkt);
+ ldns_buffer_free(buf);
+ return;
+ }
+ }
+
+ /* output the query answers */
+ ldns_rr_list* ans = ldns_pkt_answer(pkt);
+ if (ans) {
+ const char* delim = " ans=";
+ size_t i, n;
+ for (i = 0, n = ldns_rr_list_rr_count(ans); i < n; i++) {
+ ldns_rr* rr = ldns_rr_list_rr(ans, i);
+
+ if (rr) {
+ switch (ldns_rr_get_type(rr)) {
+ case LDNS_RR_TYPE_A:
+ case LDNS_RR_TYPE_AAAA: {
+ ldns_rdf* rdf = ldns_rr_rdf(rr, 0);
+ if (rdf) {
+ fprintf(out, "%s", delim);
+ delim = ",";
+ eventlog_output_ipbytes(ldns_rdf_size(rdf), ldns_rdf_data(rdf));
+ continue;
+ }
+ break;
+ }
+ default:
+ continue;
+ }
+ }
+
+ fprintf(out, " **ERROR parsing response record**\n");
+ ldns_pkt_free(pkt);
+ ldns_buffer_free(buf);
+ return;
+ }
+ }
+
+ /*
+ * Done
+ */
+ fprintf(out, "\n");
+ ldns_pkt_free(pkt);
+ ldns_buffer_free(buf);
+}