[thirdparty/systemd.git] / src / resolve / resolved-etc-hosts.c

/* SPDX-License-Identifier: LGPL-2.1+ */

#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>

#include "fd-util.h"
#include "fileio.h"
#include "hostname-util.h"
#include "resolved-dns-synthesize.h"
#include "resolved-etc-hosts.h"
#include "socket-netlink.h"
#include "string-util.h"
#include "strv.h"
#include "time-util.h"

/* Recheck /etc/hosts at most once every 2s */
#define ETC_HOSTS_RECHECK_USEC (2*USEC_PER_SEC)

static void etc_hosts_item_free(EtcHostsItem *item) {
        strv_free(item->names);
        free(item);
}

static void etc_hosts_item_by_name_free(EtcHostsItemByName *item) {
        free(item->name);
        free(item->addresses);
        free(item);
}

void etc_hosts_free(EtcHosts *hosts) {
        hosts->by_address = hashmap_free_with_destructor(hosts->by_address, etc_hosts_item_free);
        hosts->by_name = hashmap_free_with_destructor(hosts->by_name, etc_hosts_item_by_name_free);
        hosts->no_address = set_free_free(hosts->no_address);
}

void manager_etc_hosts_flush(Manager *m) {
        etc_hosts_free(&m->etc_hosts);
        m->etc_hosts_mtime = USEC_INFINITY;
        m->etc_hosts_ino = 0;
        m->etc_hosts_dev = 0;
}

static int parse_line(EtcHosts *hosts, unsigned nr, const char *line) {
        _cleanup_free_ char *address_str = NULL;
        struct in_addr_data address = {};
        bool found = false;
        EtcHostsItem *item;
        int r;

        assert(hosts);
        assert(line);

        r = extract_first_word(&line, &address_str, NULL, EXTRACT_RELAX);
        if (r < 0)
                return log_error_errno(r, "/etc/hosts:%u: failed to extract address: %m", nr);
        assert(r > 0); /* We already checked that the line is not empty, so it should contain *something* */

        r = in_addr_ifindex_from_string_auto(address_str, &address.family, &address.address, NULL);
        if (r < 0) {
                log_warning_errno(r, "/etc/hosts:%u: address '%s' is invalid, ignoring: %m", nr, address_str);
                return 0;
        }

        r = in_addr_is_null(address.family, &address.address);
        if (r < 0) {
                log_warning_errno(r, "/etc/hosts:%u: address '%s' is invalid, ignoring: %m", nr, address_str);
                return 0;
        }
        if (r > 0)
                /* This is an 0.0.0.0 or :: item, which we assume means that we shall map the specified hostname to
                 * nothing. */
                item = NULL;
        else {
                /* If this is a normal address, then simply add entry mapping it to the specified names */

                item = hashmap_get(hosts->by_address, &address);
                if (!item) {
                        r = hashmap_ensure_allocated(&hosts->by_address, &in_addr_data_hash_ops);
                        if (r < 0)
                                return log_oom();

                        item = new0(EtcHostsItem, 1);
                        if (!item)
                                return log_oom();

                        item->address = address;

                        r = hashmap_put(hosts->by_address, &item->address, item);
                        if (r < 0) {
                                free(item);
                                return log_oom();
                        }
                }
        }

        for (;;) {
                _cleanup_free_ char *name = NULL;
                EtcHostsItemByName *bn;

                r = extract_first_word(&line, &name, NULL, EXTRACT_RELAX);
                if (r < 0)
                        return log_error_errno(r, "/etc/hosts:%u: couldn't extract hostname: %m", nr);
                if (r == 0)
                        break;

                found = true;

                r = dns_name_is_valid_ldh(name);
                if (r <= 0) {
                        log_warning_errno(r, "/etc/hosts:%u: hostname \"%s\" is not valid, ignoring.", nr, name);
                        continue;
                }

                if (is_localhost(name))
                        /* Suppress the "localhost" line that is often seen */
                        continue;

                if (!item) {
                        /* Optimize the case where we don't need to store any addresses, by storing
                         * only the name in a dedicated Set instead of the hashmap */

                        r = set_ensure_allocated(&hosts->no_address, &dns_name_hash_ops);
                        if (r < 0)
                                return log_oom();

                        r = set_put(hosts->no_address, name);
                        if (r < 0)
                                return r;

                        TAKE_PTR(name);
                        continue;
                }

                r = strv_extend(&item->names, name);
                if (r < 0)
                        return log_oom();

                bn = hashmap_get(hosts->by_name, name);
                if (!bn) {
                        r = hashmap_ensure_allocated(&hosts->by_name, &dns_name_hash_ops);
                        if (r < 0)
                                return log_oom();

                        bn = new0(EtcHostsItemByName, 1);
                        if (!bn)
                                return log_oom();

                        r = hashmap_put(hosts->by_name, name, bn);
                        if (r < 0) {
                                free(bn);
                                return log_oom();
                        }

                        bn->name = TAKE_PTR(name);
                }

                if (!GREEDY_REALLOC(bn->addresses, bn->n_allocated, bn->n_addresses + 1))
                        return log_oom();

                bn->addresses[bn->n_addresses++] = &item->address;
        }

        if (!found)
                log_warning("/etc/hosts:%u: line is missing any hostnames", nr);

        return 0;
}

int etc_hosts_parse(EtcHosts *hosts, FILE *f) {
        _cleanup_(etc_hosts_free) EtcHosts t = {};
        unsigned nr = 0;
        int r;

        for (;;) {
                _cleanup_free_ char *line = NULL;
                char *l;

                r = read_line(f, LONG_LINE_MAX, &line);
                if (r < 0)
                        return log_error_errno(r, "Failed to read /etc/hosts: %m");
                if (r == 0)
                        break;

                nr++;

                l = strchr(line, '#');
                if (l)
                        *l = '\0';

                l = strstrip(line);
                if (isempty(l))
                        continue;

                r = parse_line(&t, nr, l);
                if (r < 0)
                        return r;
        }

        etc_hosts_free(hosts);
        *hosts = t;
        t = (EtcHosts) {}; /* prevent cleanup */
        return 0;
}

static int manager_etc_hosts_read(Manager *m) {
        _cleanup_fclose_ FILE *f = NULL;
        struct stat st;
        usec_t ts;
        int r;

        assert_se(sd_event_now(m->event, clock_boottime_or_monotonic(), &ts) >= 0);

        /* See if we checked /etc/hosts recently already */
        if (m->etc_hosts_last != USEC_INFINITY && m->etc_hosts_last + ETC_HOSTS_RECHECK_USEC > ts)
                return 0;

        m->etc_hosts_last = ts;

        if (m->etc_hosts_mtime != USEC_INFINITY) {
                if (stat("/etc/hosts", &st) < 0) {
                        if (errno != ENOENT)
                                return log_error_errno(errno, "Failed to stat /etc/hosts: %m");

                        manager_etc_hosts_flush(m);
                        return 0;
                }

                /* Did the mtime or ino/dev change? If not, there's no point in re-reading the file. */
                if (timespec_load(&st.st_mtim) == m->etc_hosts_mtime &&
                    st.st_ino == m->etc_hosts_ino && st.st_dev == m->etc_hosts_dev)
                        return 0;
        }

        f = fopen("/etc/hosts", "re");
        if (!f) {
                if (errno != ENOENT)
                        return log_error_errno(errno, "Failed to open /etc/hosts: %m");

                manager_etc_hosts_flush(m);
                return 0;
        }

        /* Take the timestamp at the beginning of processing, so that any changes made later are read on the next
         * invocation */
        r = fstat(fileno(f), &st);
        if (r < 0)
                return log_error_errno(errno, "Failed to fstat() /etc/hosts: %m");

        r = etc_hosts_parse(&m->etc_hosts, f);
        if (r < 0)
                return r;

        m->etc_hosts_mtime = timespec_load(&st.st_mtim);
        m->etc_hosts_ino = st.st_ino;
        m->etc_hosts_dev = st.st_dev;
        m->etc_hosts_last = ts;

        return 1;
}

int manager_etc_hosts_lookup(Manager *m, DnsQuestion* q, DnsAnswer **answer) {
        bool found_a = false, found_aaaa = false;
        struct in_addr_data k = {};
        EtcHostsItemByName *bn;
        DnsResourceKey *t;
        const char *name;
        unsigned i;
        int r;

        assert(m);
        assert(q);
        assert(answer);

        if (!m->read_etc_hosts)
                return 0;

        (void) manager_etc_hosts_read(m);

        name = dns_question_first_name(q);
        if (!name)
                return 0;

        r = dns_name_address(name, &k.family, &k.address);
        if (r > 0) {
                EtcHostsItem *item;
                DnsResourceKey *found_ptr = NULL;

                item = hashmap_get(m->etc_hosts.by_address, &k);
                if (!item)
                        return 0;

                /* We have an address in /etc/hosts that matches the queried name. Let's return successful. Actual data
                 * we'll only return if the request was for PTR. */

                DNS_QUESTION_FOREACH(t, q) {
                        if (!IN_SET(t->type, DNS_TYPE_PTR, DNS_TYPE_ANY))
                                continue;
                        if (!IN_SET(t->class, DNS_CLASS_IN, DNS_CLASS_ANY))
                                continue;

                        r = dns_name_equal(dns_resource_key_name(t), name);
                        if (r < 0)
                                return r;
                        if (r > 0) {
                                found_ptr = t;
                                break;
                        }
                }

                if (found_ptr) {
                        char **n;

                        r = dns_answer_reserve(answer, strv_length(item->names));
                        if (r < 0)
                                return r;

                        STRV_FOREACH(n, item->names) {
                                _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL;

                                rr = dns_resource_record_new(found_ptr);
                                if (!rr)
                                        return -ENOMEM;

                                rr->ptr.name = strdup(*n);
                                if (!rr->ptr.name)
                                        return -ENOMEM;

                                r = dns_answer_add(*answer, rr, 0, DNS_ANSWER_AUTHENTICATED);
                                if (r < 0)
                                        return r;
                        }
                }

                return 1;
        }

        bn = hashmap_get(m->etc_hosts.by_name, name);
        if (bn) {
                r = dns_answer_reserve(answer, bn->n_addresses);
                if (r < 0)
                        return r;
        } else {
                /* Check if name was listed with no address. If yes, continue to return an answer. */
                if (!set_contains(m->etc_hosts.no_address, name))
                        return 0;
        }

        DNS_QUESTION_FOREACH(t, q) {
                if (!IN_SET(t->type, DNS_TYPE_A, DNS_TYPE_AAAA, DNS_TYPE_ANY))
                        continue;
                if (!IN_SET(t->class, DNS_CLASS_IN, DNS_CLASS_ANY))
                        continue;

                r = dns_name_equal(dns_resource_key_name(t), name);
                if (r < 0)
                        return r;
                if (r == 0)
                        continue;

                if (IN_SET(t->type, DNS_TYPE_A, DNS_TYPE_ANY))
                        found_a = true;
                if (IN_SET(t->type, DNS_TYPE_AAAA, DNS_TYPE_ANY))
                        found_aaaa = true;

                if (found_a && found_aaaa)
                        break;
        }

        for (i = 0; bn && i < bn->n_addresses; i++) {
                _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL;

                if ((!found_a && bn->addresses[i]->family == AF_INET) ||
                    (!found_aaaa && bn->addresses[i]->family == AF_INET6))
                        continue;

                r = dns_resource_record_new_address(&rr, bn->addresses[i]->family, &bn->addresses[i]->address, bn->name);
                if (r < 0)
                        return r;

                r = dns_answer_add(*answer, rr, 0, DNS_ANSWER_AUTHENTICATED);
                if (r < 0)
                        return r;
        }

        return found_a || found_aaaa;
}
Commit	Line	Data
53e1b683	1	/* SPDX-License-Identifier: LGPL-2.1+ */
dd0bc0f1	2
ca78ad1d ZJS	3	#include <sys/stat.h>
	4	#include <sys/types.h>
	5	#include <unistd.h>
	6
dd0bc0f1 LP	7	#include "fd-util.h"
	8	#include "fileio.h"
	9	#include "hostname-util.h"
dd0bc0f1	10	#include "resolved-dns-synthesize.h"
7c777a77	11	#include "resolved-etc-hosts.h"
5c3fa98d	12	#include "socket-netlink.h"
dd0bc0f1 LP	13	#include "string-util.h"
	14	#include "strv.h"
	15	#include "time-util.h"
	16
	17	/* Recheck /etc/hosts at most once every 2s */
	18	#define ETC_HOSTS_RECHECK_USEC (2*USEC_PER_SEC)
	19
a1e92eee	20	static void etc_hosts_item_free(EtcHostsItem *item) {
37b7cc8d ZJS	21	strv_free(item->names);
	22	free(item);
	23	}
dd0bc0f1	24
a1e92eee	25	static void etc_hosts_item_by_name_free(EtcHostsItemByName *item) {
37b7cc8d ZJS	26	free(item->name);
	27	free(item->addresses);
	28	free(item);
	29	}
dd0bc0f1	30
78fc21a1	31	void etc_hosts_free(EtcHosts *hosts) {
37b7cc8d ZJS	32	hosts->by_address = hashmap_free_with_destructor(hosts->by_address, etc_hosts_item_free);
37b7cc8d ZJS	33	hosts->by_name = hashmap_free_with_destructor(hosts->by_name, etc_hosts_item_by_name_free);
fd373593	34	hosts->no_address = set_free_free(hosts->no_address);
37b7cc8d	35	}
dd0bc0f1	36
37b7cc8d ZJS	37	void manager_etc_hosts_flush(Manager *m) {
37b7cc8d ZJS	38	etc_hosts_free(&m->etc_hosts);
dd0bc0f1	39	m->etc_hosts_mtime = USEC_INFINITY;
aa5408e2 GS	40	m->etc_hosts_ino = 0;
aa5408e2 GS	41	m->etc_hosts_dev = 0;
dd0bc0f1 LP	42	}
dd0bc0f1 LP	43
37b7cc8d	44	static int parse_line(EtcHosts hosts, unsigned nr, const char line) {
0351eb11 YW	45	_cleanup_free_ char *address_str = NULL;
0351eb11 YW	46	struct in_addr_data address = {};
fd373593	47	bool found = false;
dd0bc0f1	48	EtcHostsItem *item;
dd0bc0f1 LP	49	int r;
dd0bc0f1 LP	50
37b7cc8d	51	assert(hosts);
0351eb11	52	assert(line);
dd0bc0f1	53
0351eb11 YW	54	r = extract_first_word(&line, &address_str, NULL, EXTRACT_RELAX);
0351eb11 YW	55	if (r < 0)
bd005277 ZJS	56	return log_error_errno(r, "/etc/hosts:%u: failed to extract address: %m", nr);
bd005277 ZJS	57	assert(r > 0); /* We already checked that the line is not empty, so it should contain something */
0351eb11	58
7bf8c3de	59	r = in_addr_ifindex_from_string_auto(address_str, &address.family, &address.address, NULL);
bd005277 ZJS	60	if (r < 0) {
	61	log_warning_errno(r, "/etc/hosts:%u: address '%s' is invalid, ignoring: %m", nr, address_str);
	62	return 0;
	63	}
0351eb11 YW	64
0351eb11 YW	65	r = in_addr_is_null(address.family, &address.address);
bd005277 ZJS	66	if (r < 0) {
	67	log_warning_errno(r, "/etc/hosts:%u: address '%s' is invalid, ignoring: %m", nr, address_str);
	68	return 0;
	69	}
dd0bc0f1 LP	70	if (r > 0)
	71	/* This is an 0.0.0.0 or :: item, which we assume means that we shall map the specified hostname to
	72	* nothing. */
	73	item = NULL;
	74	else {
78fc21a1	75	/* If this is a normal address, then simply add entry mapping it to the specified names */
dd0bc0f1	76
37b7cc8d	77	item = hashmap_get(hosts->by_address, &address);
0351eb11	78	if (!item) {
37b7cc8d	79	r = hashmap_ensure_allocated(&hosts->by_address, &in_addr_data_hash_ops);
dd0bc0f1 LP	80	if (r < 0)
	81	return log_oom();
	82
0351eb11	83	item = new0(EtcHostsItem, 1);
dd0bc0f1 LP	84	if (!item)
	85	return log_oom();
	86
0351eb11	87	item->address = address;
dd0bc0f1	88
37b7cc8d	89	r = hashmap_put(hosts->by_address, &item->address, item);
dd0bc0f1 LP	90	if (r < 0) {
	91	free(item);
	92	return log_oom();
	93	}
	94	}
	95	}
	96
0351eb11 YW	97	for (;;) {
0351eb11 YW	98	_cleanup_free_ char *name = NULL;
dd0bc0f1 LP	99	EtcHostsItemByName *bn;
dd0bc0f1 LP	100
0351eb11 YW	101	r = extract_first_word(&line, &name, NULL, EXTRACT_RELAX);
0351eb11 YW	102	if (r < 0)
38b38500	103	return log_error_errno(r, "/etc/hosts:%u: couldn't extract hostname: %m", nr);
0351eb11 YW	104	if (r == 0)
	105	break;
	106
fd373593 ZJS	107	found = true;
fd373593 ZJS	108
7470cc4c	109	r = dns_name_is_valid_ldh(name);
bd005277 ZJS	110	if (r <= 0) {
	111	log_warning_errno(r, "/etc/hosts:%u: hostname \"%s\" is not valid, ignoring.", nr, name);
	112	continue;
	113	}
	114
fd373593	115	if (is_localhost(name))
0351eb11	116	/* Suppress the "localhost" line that is often seen */
0351eb11	117	continue;
0351eb11	118
fd373593 ZJS	119	if (!item) {
	120	/* Optimize the case where we don't need to store any addresses, by storing
	121	* only the name in a dedicated Set instead of the hashmap */
	122
	123	r = set_ensure_allocated(&hosts->no_address, &dns_name_hash_ops);
0351eb11 YW	124	if (r < 0)
0351eb11 YW	125	return log_oom();
fd373593 ZJS	126
	127	r = set_put(hosts->no_address, name);
	128	if (r < 0)
	129	return r;
	130
	131	TAKE_PTR(name);
	132	continue;
0351eb11 YW	133	}
0351eb11 YW	134
fd373593 ZJS	135	r = strv_extend(&item->names, name);
	136	if (r < 0)
	137	return log_oom();
	138
37b7cc8d	139	bn = hashmap_get(hosts->by_name, name);
dd0bc0f1	140	if (!bn) {
37b7cc8d	141	r = hashmap_ensure_allocated(&hosts->by_name, &dns_name_hash_ops);
dd0bc0f1 LP	142	if (r < 0)
	143	return log_oom();
	144
	145	bn = new0(EtcHostsItemByName, 1);
	146	if (!bn)
	147	return log_oom();
	148
37b7cc8d	149	r = hashmap_put(hosts->by_name, name, bn);
dd0bc0f1	150	if (r < 0) {
dd0bc0f1 LP	151	free(bn);
	152	return log_oom();
	153	}
0351eb11 YW	154
0351eb11 YW	155	bn->name = TAKE_PTR(name);
dd0bc0f1 LP	156	}
dd0bc0f1 LP	157
fd373593 ZJS	158	if (!GREEDY_REALLOC(bn->addresses, bn->n_allocated, bn->n_addresses + 1))
fd373593 ZJS	159	return log_oom();
dd0bc0f1	160
fd373593	161	bn->addresses[bn->n_addresses++] = &item->address;
dd0bc0f1 LP	162	}
dd0bc0f1 LP	163
baaa35ad	164	if (!found)
38b38500	165	log_warning("/etc/hosts:%u: line is missing any hostnames", nr);
dd0bc0f1	166
0351eb11	167	return 0;
dd0bc0f1 LP	168	}
dd0bc0f1 LP	169
78fc21a1	170	int etc_hosts_parse(EtcHosts hosts, FILE f) {
37b7cc8d	171	_cleanup_(etc_hosts_free) EtcHosts t = {};
37b7cc8d ZJS	172	unsigned nr = 0;
	173	int r;
	174
7c777a77 LP	175	for (;;) {
7c777a77 LP	176	_cleanup_free_ char *line = NULL;
37b7cc8d ZJS	177	char *l;
37b7cc8d ZJS	178
7c777a77 LP	179	r = read_line(f, LONG_LINE_MAX, &line);
	180	if (r < 0)
	181	return log_error_errno(r, "Failed to read /etc/hosts: %m");
	182	if (r == 0)
	183	break;
	184
37b7cc8d ZJS	185	nr++;
37b7cc8d ZJS	186
bd005277 ZJS	187	l = strchr(line, '#');
	188	if (l)
	189	*l = '\0';
	190
37b7cc8d ZJS	191	l = strstrip(line);
	192	if (isempty(l))
	193	continue;
37b7cc8d ZJS	194
	195	r = parse_line(&t, nr, l);
	196	if (r < 0)
	197	return r;
	198	}
	199
be19cdf3	200	etc_hosts_free(hosts);
37b7cc8d ZJS	201	*hosts = t;
	202	t = (EtcHosts) {}; /* prevent cleanup */
	203	return 0;
	204	}
	205
452ca091	206	static int manager_etc_hosts_read(Manager *m) {
dd0bc0f1	207	_cleanup_fclose_ FILE *f = NULL;
dd0bc0f1 LP	208	struct stat st;
dd0bc0f1 LP	209	usec_t ts;
dd0bc0f1 LP	210	int r;
	211
	212	assert_se(sd_event_now(m->event, clock_boottime_or_monotonic(), &ts) >= 0);
	213
	214	/* See if we checked /etc/hosts recently already */
	215	if (m->etc_hosts_last != USEC_INFINITY && m->etc_hosts_last + ETC_HOSTS_RECHECK_USEC > ts)
	216	return 0;
	217
	218	m->etc_hosts_last = ts;
	219
	220	if (m->etc_hosts_mtime != USEC_INFINITY) {
	221	if (stat("/etc/hosts", &st) < 0) {
37b7cc8d ZJS	222	if (errno != ENOENT)
37b7cc8d ZJS	223	return log_error_errno(errno, "Failed to stat /etc/hosts: %m");
dd0bc0f1	224
37b7cc8d ZJS	225	manager_etc_hosts_flush(m);
37b7cc8d ZJS	226	return 0;
dd0bc0f1 LP	227	}
dd0bc0f1 LP	228
aa5408e2 GS	229	/* Did the mtime or ino/dev change? If not, there's no point in re-reading the file. */
	230	if (timespec_load(&st.st_mtim) == m->etc_hosts_mtime &&
	231	st.st_ino == m->etc_hosts_ino && st.st_dev == m->etc_hosts_dev)
dd0bc0f1 LP	232	return 0;
	233	}
	234
	235	f = fopen("/etc/hosts", "re");
	236	if (!f) {
37b7cc8d ZJS	237	if (errno != ENOENT)
37b7cc8d ZJS	238	return log_error_errno(errno, "Failed to open /etc/hosts: %m");
dd0bc0f1	239
37b7cc8d ZJS	240	manager_etc_hosts_flush(m);
37b7cc8d ZJS	241	return 0;
dd0bc0f1 LP	242	}
	243
	244	/* Take the timestamp at the beginning of processing, so that any changes made later are read on the next
	245	* invocation */
	246	r = fstat(fileno(f), &st);
	247	if (r < 0)
	248	return log_error_errno(errno, "Failed to fstat() /etc/hosts: %m");
	249
37b7cc8d	250	r = etc_hosts_parse(&m->etc_hosts, f);
be19cdf3	251	if (r < 0)
37b7cc8d	252	return r;
dd0bc0f1 LP	253
dd0bc0f1 LP	254	m->etc_hosts_mtime = timespec_load(&st.st_mtim);
aa5408e2 GS	255	m->etc_hosts_ino = st.st_ino;
aa5408e2 GS	256	m->etc_hosts_dev = st.st_dev;
dd0bc0f1 LP	257	m->etc_hosts_last = ts;
	258
	259	return 1;
dd0bc0f1 LP	260	}
	261
	262	int manager_etc_hosts_lookup(Manager m, DnsQuestion q, DnsAnswer **answer) {
	263	bool found_a = false, found_aaaa = false;
0351eb11	264	struct in_addr_data k = {};
dd0bc0f1	265	EtcHostsItemByName *bn;
dd0bc0f1 LP	266	DnsResourceKey *t;
	267	const char *name;
	268	unsigned i;
	269	int r;
	270
	271	assert(m);
	272	assert(q);
	273	assert(answer);
	274
86317087 YW	275	if (!m->read_etc_hosts)
	276	return 0;
	277
be19cdf3	278	(void) manager_etc_hosts_read(m);
dd0bc0f1 LP	279
	280	name = dns_question_first_name(q);
	281	if (!name)
	282	return 0;
	283
	284	r = dns_name_address(name, &k.family, &k.address);
	285	if (r > 0) {
	286	EtcHostsItem *item;
	287	DnsResourceKey *found_ptr = NULL;
	288
37b7cc8d	289	item = hashmap_get(m->etc_hosts.by_address, &k);
dd0bc0f1 LP	290	if (!item)
	291	return 0;
	292
	293	/* We have an address in /etc/hosts that matches the queried name. Let's return successful. Actual data
	294	* we'll only return if the request was for PTR. */
	295
	296	DNS_QUESTION_FOREACH(t, q) {
	297	if (!IN_SET(t->type, DNS_TYPE_PTR, DNS_TYPE_ANY))
	298	continue;
	299	if (!IN_SET(t->class, DNS_CLASS_IN, DNS_CLASS_ANY))
	300	continue;
	301
1c02e7ba	302	r = dns_name_equal(dns_resource_key_name(t), name);
dd0bc0f1 LP	303	if (r < 0)
	304	return r;
	305	if (r > 0) {
	306	found_ptr = t;
	307	break;
	308	}
	309	}
	310
	311	if (found_ptr) {
	312	char **n;
	313
	314	r = dns_answer_reserve(answer, strv_length(item->names));
	315	if (r < 0)
	316	return r;
	317
	318	STRV_FOREACH(n, item->names) {
	319	_cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL;
	320
	321	rr = dns_resource_record_new(found_ptr);
	322	if (!rr)
	323	return -ENOMEM;
	324
	325	rr->ptr.name = strdup(*n);
	326	if (!rr->ptr.name)
	327	return -ENOMEM;
	328
	329	r = dns_answer_add(*answer, rr, 0, DNS_ANSWER_AUTHENTICATED);
	330	if (r < 0)
	331	return r;
	332	}
	333	}
	334
	335	return 1;
	336	}
	337
37b7cc8d	338	bn = hashmap_get(m->etc_hosts.by_name, name);
fd373593 ZJS	339	if (bn) {
	340	r = dns_answer_reserve(answer, bn->n_addresses);
	341	if (r < 0)
	342	return r;
	343	} else {
	344	/* Check if name was listed with no address. If yes, continue to return an answer. */
	345	if (!set_contains(m->etc_hosts.no_address, name))
	346	return 0;
	347	}
dd0bc0f1 LP	348
	349	DNS_QUESTION_FOREACH(t, q) {
	350	if (!IN_SET(t->type, DNS_TYPE_A, DNS_TYPE_AAAA, DNS_TYPE_ANY))
	351	continue;
	352	if (!IN_SET(t->class, DNS_CLASS_IN, DNS_CLASS_ANY))
	353	continue;
	354
1c02e7ba	355	r = dns_name_equal(dns_resource_key_name(t), name);
dd0bc0f1 LP	356	if (r < 0)
	357	return r;
	358	if (r == 0)
	359	continue;
	360
	361	if (IN_SET(t->type, DNS_TYPE_A, DNS_TYPE_ANY))
	362	found_a = true;
	363	if (IN_SET(t->type, DNS_TYPE_AAAA, DNS_TYPE_ANY))
	364	found_aaaa = true;
	365
	366	if (found_a && found_aaaa)
	367	break;
	368	}
	369
fd373593	370	for (i = 0; bn && i < bn->n_addresses; i++) {
dd0bc0f1 LP	371	_cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL;
dd0bc0f1 LP	372
0351eb11 YW	373	if ((!found_a && bn->addresses[i]->family == AF_INET) \|\|
0351eb11 YW	374	(!found_aaaa && bn->addresses[i]->family == AF_INET6))
dd0bc0f1 LP	375	continue;
dd0bc0f1 LP	376
0351eb11	377	r = dns_resource_record_new_address(&rr, bn->addresses[i]->family, &bn->addresses[i]->address, bn->name);
dd0bc0f1 LP	378	if (r < 0)
	379	return r;
	380
	381	r = dns_answer_add(*answer, rr, 0, DNS_ANSWER_AUTHENTICATED);
	382	if (r < 0)
	383	return r;
	384	}
	385
4050e04b	386	return found_a \|\| found_aaaa;
dd0bc0f1	387	}