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resolvectl: add new "monitor" verb

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This commit is contained in:
Lennart Poettering 2022-09-28 12:46:21 +02:00
parent 72c2d39ecb
commit fffbf1dc99
2 changed files with 270 additions and 4 deletions
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23
man/resolvectl.xml
View File

@ -199,6 +199,19 @@
automatically, an explicit reverting is not necessary in that case.</para></listitem>
</varlistentry>
<varlistentry>
<term><command>monitor</command></term>
<listitem><para>Show a continous stream of local client resolution queries and their
responses. Whenever a local query is completed the query's DNS resource lookup key and resource
records are shown. Note that this displays queries issued locally only, and does not immediately
relate to DNS requests submitted to configured DNS servers or the LLMNR or MulticastDNS zones, as
lookups may be answered from the local cache, or might result in multiple DNS transactions (for
example to validate DNSSEC information). If CNAME/CNAME redirection chains are followed, a separate
query will be displayed for each element of the chain. Use <option>--json=</option> to enable JSON
output.</para></listitem>
</varlistentry>
<xi:include href="systemctl.xml" xpointer="log-level" />
</variablelist>
</refsect1>
@ -379,9 +392,17 @@
query response are shown. Otherwise, this output is suppressed.</para></listitem>
</varlistentry>
<xi:include href="standard-options.xml" xpointer="json" />
<varlistentry>
<term><option>-j</option></term>
<listitem><para>Short for <option>--json=auto</option></para></listitem>
</varlistentry>
<xi:include href="standard-options.xml" xpointer="no-pager" />
<xi:include href="standard-options.xml" xpointer="help" />
<xi:include href="standard-options.xml" xpointer="version" />
<xi:include href="standard-options.xml" xpointer="no-pager" />
</variablelist>
</refsect1>

251
src/resolve/resolvectl.c
View File

@ -15,11 +15,13 @@
#include "bus-map-properties.h"
#include "bus-message-util.h"
#include "dns-domain.h"
#include "errno-list.h"
#include "escape.h"
#include "format-table.h"
#include "format-util.h"
#include "gcrypt-util.h"
#include "hostname-util.h"
#include "json.h"
#include "main-func.h"
#include "missing_network.h"
#include "netlink-util.h"
@ -41,6 +43,7 @@
#include "strv.h"
#include "terminal-util.h"
#include "utf8.h"
#include "varlink.h"
#include "verb-log-control.h"
#include "verbs.h"
@ -51,6 +54,7 @@ static uint16_t arg_type = 0;
static uint16_t arg_class = 0;
static bool arg_legend = true;
static uint64_t arg_flags = 0;
static JsonFormatFlags arg_json_format_flags = JSON_FORMAT_OFF;
static PagerFlags arg_pager_flags = 0;
bool arg_ifindex_permissive = false; /* If true, don't generate an error if the specified interface index doesn't exist */
static const char *arg_service_family = NULL;
@ -2503,6 +2507,227 @@ static int verb_log_level(int argc, char *argv[], void *userdata) {
return verb_log_control_common(bus, "org.freedesktop.resolve1", argv[0], argc == 2 ? argv[1] : NULL);
}
static int monitor_rkey_from_json(JsonVariant *v, DnsResourceKey **ret_key) {
_cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL;
uint16_t type = 0, class = 0;
const char *name = NULL;
int r;
JsonDispatch dispatch_table[] = {
{ "class", JSON_VARIANT_INTEGER, json_dispatch_uint16, PTR_TO_SIZE(&class), JSON_MANDATORY },
{ "type", JSON_VARIANT_INTEGER, json_dispatch_uint16, PTR_TO_SIZE(&type), JSON_MANDATORY },
{ "name", JSON_VARIANT_STRING, json_dispatch_const_string, PTR_TO_SIZE(&name), JSON_MANDATORY },
{}
};
assert(v);
assert(ret_key);
r = json_dispatch(v, dispatch_table, NULL, 0, NULL);
if (r < 0)
return r;
key = dns_resource_key_new(class, type, name);
if (!key)
return -ENOMEM;
*ret_key = TAKE_PTR(key);
return 0;
}
static int print_question(char prefix, const char *color, JsonVariant *question) {
JsonVariant *q = NULL;
int r;
assert(color);
JSON_VARIANT_ARRAY_FOREACH(q, question) {
_cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL;
char buf[DNS_RESOURCE_KEY_STRING_MAX];
r = monitor_rkey_from_json(q, &key);
if (r < 0) {
log_warning_errno(r, "Received monitor message with invalid question key, ignoring: %m");
continue;
}
printf("%s%s %c%s: %s\n",
color,
special_glyph(SPECIAL_GLYPH_ARROW_RIGHT),
prefix,
ansi_normal(),
dns_resource_key_to_string(key, buf, sizeof(buf)));
}
return 0;
}
static int print_answer(JsonVariant *answer) {
JsonVariant *a;
int r;
JSON_VARIANT_ARRAY_FOREACH(a, answer) {
_cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL;
_cleanup_free_ void *d = NULL;
JsonVariant *jraw;
const char *s;
size_t l;
jraw = json_variant_by_key(a, "raw");
if (!jraw) {
log_warning("Received monitor answer lacking valid raw data, ignoring.");
continue;
}
r = json_variant_unbase64(jraw, &d, &l);
if (r < 0) {
log_warning_errno(r, "Failed to undo base64 encoding of monitor answer raw data, ignoring.");
continue;
}
r = dns_resource_record_new_from_raw(&rr, d, l);
if (r < 0) {
log_warning_errno(r, "Failed to parse monitor answer RR, ingoring: %m");
continue;
}
s = dns_resource_record_to_string(rr);
if (!s)
return log_oom();
printf("%s%s A%s: %s\n",
ansi_highlight_yellow(),
special_glyph(SPECIAL_GLYPH_ARROW_LEFT),
ansi_normal(),
s);
}
return 0;
}
static void monitor_query_dump(JsonVariant *v) {
_cleanup_(json_variant_unrefp) JsonVariant *question = NULL, *answer = NULL, *collected_questions = NULL;
int rcode = -1, error = 0, r;
const char *state = NULL;
assert(v);
JsonDispatch dispatch_table[] = {
{ "question", JSON_VARIANT_ARRAY, json_dispatch_variant, PTR_TO_SIZE(&question), JSON_MANDATORY },
{ "answer", JSON_VARIANT_ARRAY, json_dispatch_variant, PTR_TO_SIZE(&answer), 0 },
{ "collectedQuestions", JSON_VARIANT_ARRAY, json_dispatch_variant, PTR_TO_SIZE(&collected_questions), 0 },
{ "state", JSON_VARIANT_STRING, json_dispatch_const_string, PTR_TO_SIZE(&state), JSON_MANDATORY },
{ "rcode", JSON_VARIANT_INTEGER, json_dispatch_int, PTR_TO_SIZE(&rcode), 0 },
{ "errno", JSON_VARIANT_INTEGER, json_dispatch_int, PTR_TO_SIZE(&error), 0 },
{}
};
r = json_dispatch(v, dispatch_table, NULL, 0, NULL);
if (r < 0)
return (void) log_warning("Received malformed monitor message, ignoring.");
/* First show the current question */
print_question('Q', ansi_highlight_cyan(), question);
/* And then show the questions that led to this one in case this was a CNAME chain */
print_question('C', ansi_highlight_grey(), collected_questions);
printf("%s%s S%s: %s\n",
streq_ptr(state, "success") ? ansi_highlight_green() : ansi_highlight_red(),
special_glyph(SPECIAL_GLYPH_ARROW_LEFT),
ansi_normal(),
strna(streq_ptr(state, "errno") ? errno_to_name(error) :
streq_ptr(state, "rcode-failure") ? dns_rcode_to_string(rcode) :
state));
print_answer(answer);
}
static int monitor_reply(
Varlink *link,
JsonVariant *parameters,
const char *error_id,
VarlinkReplyFlags flags,
void *userdata) {
assert(link);
if (error_id) {
bool disconnect;
disconnect = streq(error_id, VARLINK_ERROR_DISCONNECTED);
if (disconnect)
log_info("Disconnected.");
else
log_error("Varlink error: %s", error_id);
(void) sd_event_exit(ASSERT_PTR(varlink_get_event(link)), disconnect ? EXIT_SUCCESS : EXIT_FAILURE);
return 0;
}
if (json_variant_by_key(parameters, "ready")) {
/* The first message coming in will just indicate that we are now subscribed. We let our
* caller know if they asked for it. Once the caller sees this they should know that we are
* not going to miss any queries anymore. */
(void) sd_notify(/* unset_environment=false */ false, "READY=1");
return 0;
}
if (arg_json_format_flags & JSON_FORMAT_OFF) {
monitor_query_dump(parameters);
printf("\n");
} else
json_variant_dump(parameters, arg_json_format_flags, NULL, NULL);
fflush(stdout);
return 0;
}
static int verb_monitor(int argc, char *argv[], void *userdata) {
_cleanup_(sd_event_unrefp) sd_event *event = NULL;
_cleanup_(varlink_unrefp) Varlink *vl = NULL;
int r, c;
r = sd_event_default(&event);
if (r < 0)
return log_error_errno(r, "Failed to get event loop: %m");
r = sd_event_set_signal_exit(event, true);
if (r < 0)
return log_error_errno(r, "Failed to enable exit on SIGINT/SIGTERM: %m");
r = varlink_connect_address(&vl, "/run/systemd/resolve/io.systemd.Resolve.Monitor");
if (r < 0)
return log_error_errno(r, "Failed to connect to query monitoring service /run/systemd/resolve/io.systemd.Resolve.Monitor: %m");
r = varlink_set_relative_timeout(vl, USEC_INFINITY); /* We want the monitor to run basically forever */
if (r < 0)
return log_error_errno(r, "Failed to set varlink time-out: %m");
r = varlink_attach_event(vl, event, SD_EVENT_PRIORITY_NORMAL);
if (r < 0)
return log_error_errno(r, "Failed to attach varlink connection to event loop: %m");
r = varlink_bind_reply(vl, monitor_reply);
if (r < 0)
return log_error_errno(r, "Failed to bind reply callback to varlink connection: %m");
r = varlink_observe(vl, "io.systemd.Resolve.Monitor.SubscribeQueryResults", NULL);
if (r < 0)
return log_error_errno(r, "Failed to issue SubscribeQueryResults() varlink call: %m");
r = sd_event_loop(event);
if (r < 0)
return log_error_errno(r, "Failed to run event loop: %m");
r = sd_event_get_exit_code(event, &c);
if (r < 0)
return log_error_errno(r, "Failed to get exit code: %m");
return c;
}
static void help_protocol_types(void) {
if (arg_legend)
puts("Known protocol types:");
@ -2608,6 +2833,7 @@ static int native_help(void) {
" reset-statistics Reset resolver statistics\n"
" flush-caches Flush all local DNS caches\n"
" reset-server-features Forget learnt DNS server feature levels\n"
" monitor Monitor DNS queries\n"
" dns [LINK [SERVER...]] Get/set per-interface DNS server address\n"
" domain [LINK [DOMAIN...]] Get/set per-interface search domain\n"
" default-route [LINK [BOOL]] Get/set per-interface default route flag\n"
@ -2636,11 +2862,16 @@ static int native_help(void) {
" --cache=BOOL Allow response from cache (default: yes)\n"
" --zone=BOOL Allow response from locally registered mDNS/LLMNR\n"
" records (default: yes)\n"
" --trust-anchor=BOOL Allow response from local trust anchor (default: yes)\n"
" --trust-anchor=BOOL Allow response from local trust anchor (default:\n"
" yes)\n"
" --network=BOOL Allow response from network (default: yes)\n"
" --search=BOOL Use search domains for single-label names (default: yes)\n"
" --search=BOOL Use search domains for single-label names (default:\n"
" yes)\n"
" --raw[=payload|packet] Dump the answer as binary data\n"
" --legend=BOOL Print headers and additional info (default: yes)\n"
" --json=MODE Output as JSON\n"
" -j Same as --json=pretty on tty, --json=short\n"
" otherwise\n"
"\nSee the %s for details.\n",
program_invocation_short_name,
ansi_highlight(),
@ -2987,6 +3218,7 @@ static int native_parse_argv(int argc, char *argv[]) {
ARG_RAW,
ARG_SEARCH,
ARG_NO_PAGER,
ARG_JSON,
};
static const struct option options[] = {
@ -3009,6 +3241,7 @@ static int native_parse_argv(int argc, char *argv[]) {
{ "raw", optional_argument, NULL, ARG_RAW },
{ "search", required_argument, NULL, ARG_SEARCH },
{ "no-pager", no_argument, NULL, ARG_NO_PAGER },
{ "json", required_argument, NULL, ARG_JSON },
{}
};
@ -3017,7 +3250,7 @@ static int native_parse_argv(int argc, char *argv[]) {
assert(argc >= 0);
assert(argv);
while ((c = getopt_long(argc, argv, "h46i:t:c:p:", options, NULL)) >= 0)
while ((c = getopt_long(argc, argv, "h46i:t:c:p:j", options, NULL)) >= 0)
switch (c) {
case 'h':
@ -3192,6 +3425,17 @@ static int native_parse_argv(int argc, char *argv[]) {
arg_pager_flags |= PAGER_DISABLE;
break;
case ARG_JSON:
r = parse_json_argument(optarg, &arg_json_format_flags);
if (r <= 0)
return r;
break;
case 'j':
arg_json_format_flags = JSON_FORMAT_PRETTY_AUTO|JSON_FORMAT_COLOR_AUTO;
break;
case '?':
return -EINVAL;
@ -3235,6 +3479,7 @@ static int native_main(int argc, char *argv[], sd_bus *bus) {
{ "nta", VERB_ANY, VERB_ANY, 0, verb_nta },
{ "revert", VERB_ANY, 2, 0, verb_revert_link },
{ "log-level", VERB_ANY, 2, 0, verb_log_level },
{ "monitor", VERB_ANY, 1, 0, verb_monitor },
{}
};