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Systemd/src/resolve/resolved-manager.c

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/* SPDX-License-Identifier: LGPL-2.1+ */
/***
This file is part of systemd.
Copyright 2014 Tom Gundersen <teg@jklm.no>
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <netinet/in.h>
#include <poll.h>
#include <stdio_ext.h>
#include <sys/ioctl.h>
#if HAVE_LIBIDN2
#include <idn2.h>
#endif
#include "af-list.h"
#include "alloc-util.h"
#include "dirent-util.h"
#include "dns-domain.h"
#include "fd-util.h"
#include "fileio-label.h"
#include "hostname-util.h"
#include "io-util.h"
#include "netlink-util.h"
#include "network-internal.h"
#include "ordered-set.h"
#include "parse-util.h"
#include "random-util.h"
#include "resolved-bus.h"
#include "resolved-conf.h"
#include "resolved-dnssd.h"
#include "resolved-dns-stub.h"
#include "resolved-etc-hosts.h"
#include "resolved-llmnr.h"
#include "resolved-manager.h"
#include "resolved-mdns.h"
#include "resolved-resolv-conf.h"
#include "socket-util.h"
#include "string-table.h"
#include "string-util.h"
#include "utf8.h"
#define SEND_TIMEOUT_USEC (200 * USEC_PER_MSEC)
static int manager_process_link(sd_netlink *rtnl, sd_netlink_message *mm, void *userdata) {
Manager *m = userdata;
uint16_t type;
Link *l;
int ifindex, r;
assert(rtnl);
assert(m);
assert(mm);
r = sd_netlink_message_get_type(mm, &type);
if (r < 0)
goto fail;
r = sd_rtnl_message_link_get_ifindex(mm, &ifindex);
if (r < 0)
goto fail;
l = hashmap_get(m->links, INT_TO_PTR(ifindex));
switch (type) {
case RTM_NEWLINK:{
bool is_new = !l;
if (!l) {
r = link_new(m, &l, ifindex);
if (r < 0)
goto fail;
}
r = link_process_rtnl(l, mm);
if (r < 0)
goto fail;
r = link_update(l);
if (r < 0)
goto fail;
if (is_new)
log_debug("Found new link %i/%s", ifindex, l->name);
break;
}
case RTM_DELLINK:
if (l) {
log_debug("Removing link %i/%s", l->ifindex, l->name);
link_remove_user(l);
link_free(l);
}
break;
}
return 0;
fail:
log_warning_errno(r, "Failed to process RTNL link message: %m");
return 0;
}
static int manager_process_address(sd_netlink *rtnl, sd_netlink_message *mm, void *userdata) {
Manager *m = userdata;
union in_addr_union address;
uint16_t type;
int r, ifindex, family;
LinkAddress *a;
Link *l;
assert(rtnl);
assert(mm);
assert(m);
r = sd_netlink_message_get_type(mm, &type);
if (r < 0)
goto fail;
r = sd_rtnl_message_addr_get_ifindex(mm, &ifindex);
if (r < 0)
goto fail;
l = hashmap_get(m->links, INT_TO_PTR(ifindex));
if (!l)
return 0;
r = sd_rtnl_message_addr_get_family(mm, &family);
if (r < 0)
goto fail;
switch (family) {
case AF_INET:
r = sd_netlink_message_read_in_addr(mm, IFA_LOCAL, &address.in);
if (r < 0) {
r = sd_netlink_message_read_in_addr(mm, IFA_ADDRESS, &address.in);
if (r < 0)
goto fail;
}
break;
case AF_INET6:
r = sd_netlink_message_read_in6_addr(mm, IFA_LOCAL, &address.in6);
if (r < 0) {
r = sd_netlink_message_read_in6_addr(mm, IFA_ADDRESS, &address.in6);
if (r < 0)
goto fail;
}
break;
default:
return 0;
}
a = link_find_address(l, family, &address);
switch (type) {
case RTM_NEWADDR:
if (!a) {
r = link_address_new(l, &a, family, &address);
if (r < 0)
return r;
}
r = link_address_update_rtnl(a, mm);
if (r < 0)
return r;
break;
case RTM_DELADDR:
link_address_free(a);
break;
}
return 0;
fail:
log_warning_errno(r, "Failed to process RTNL address message: %m");
return 0;
}
static int manager_rtnl_listen(Manager *m) {
_cleanup_(sd_netlink_message_unrefp) sd_netlink_message *req = NULL, *reply = NULL;
sd_netlink_message *i;
int r;
assert(m);
/* First, subscribe to interfaces coming and going */
r = sd_netlink_open(&m->rtnl);
if (r < 0)
return r;
r = sd_netlink_attach_event(m->rtnl, m->event, SD_EVENT_PRIORITY_IMPORTANT);
if (r < 0)
return r;
r = sd_netlink_add_match(m->rtnl, RTM_NEWLINK, manager_process_link, m);
if (r < 0)
return r;
r = sd_netlink_add_match(m->rtnl, RTM_DELLINK, manager_process_link, m);
if (r < 0)
return r;
r = sd_netlink_add_match(m->rtnl, RTM_NEWADDR, manager_process_address, m);
if (r < 0)
return r;
r = sd_netlink_add_match(m->rtnl, RTM_DELADDR, manager_process_address, m);
if (r < 0)
return r;
/* Then, enumerate all links */
r = sd_rtnl_message_new_link(m->rtnl, &req, RTM_GETLINK, 0);
if (r < 0)
return r;
r = sd_netlink_message_request_dump(req, true);
if (r < 0)
return r;
r = sd_netlink_call(m->rtnl, req, 0, &reply);
if (r < 0)
return r;
for (i = reply; i; i = sd_netlink_message_next(i)) {
r = manager_process_link(m->rtnl, i, m);
if (r < 0)
return r;
}
req = sd_netlink_message_unref(req);
reply = sd_netlink_message_unref(reply);
/* Finally, enumerate all addresses, too */
r = sd_rtnl_message_new_addr(m->rtnl, &req, RTM_GETADDR, 0, AF_UNSPEC);
if (r < 0)
return r;
r = sd_netlink_message_request_dump(req, true);
if (r < 0)
return r;
r = sd_netlink_call(m->rtnl, req, 0, &reply);
if (r < 0)
return r;
for (i = reply; i; i = sd_netlink_message_next(i)) {
r = manager_process_address(m->rtnl, i, m);
if (r < 0)
return r;
}
return r;
}
static int on_network_event(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
Manager *m = userdata;
Iterator i;
Link *l;
int r;
assert(m);
sd_network_monitor_flush(m->network_monitor);
HASHMAP_FOREACH(l, m->links, i) {
r = link_update(l);
if (r < 0)
log_warning_errno(r, "Failed to update monitor information for %i: %m", l->ifindex);
}
(void) manager_write_resolv_conf(m);
return 0;
}
static int manager_network_monitor_listen(Manager *m) {
int r, fd, events;
assert(m);
r = sd_network_monitor_new(&m->network_monitor, NULL);
if (r < 0)
return r;
fd = sd_network_monitor_get_fd(m->network_monitor);
if (fd < 0)
return fd;
events = sd_network_monitor_get_events(m->network_monitor);
if (events < 0)
return events;
r = sd_event_add_io(m->event, &m->network_event_source, fd, events, &on_network_event, m);
if (r < 0)
return r;
r = sd_event_source_set_priority(m->network_event_source, SD_EVENT_PRIORITY_IMPORTANT+5);
if (r < 0)
return r;
(void) sd_event_source_set_description(m->network_event_source, "network-monitor");
return 0;
}
static int determine_hostname(char **full_hostname, char **llmnr_hostname, char **mdns_hostname) {
_cleanup_free_ char *h = NULL, *n = NULL;
#if HAVE_LIBIDN2
_cleanup_free_ char *utf8 = NULL;
#elif HAVE_LIBIDN
int k;
#endif
char label[DNS_LABEL_MAX];
const char *p, *decoded;
int r;
assert(full_hostname);
assert(llmnr_hostname);
assert(mdns_hostname);
/* Extract and normalize the first label of the locally configured hostname, and check it's not "localhost". */
r = gethostname_strict(&h);
if (r < 0)
return log_debug_errno(r, "Can't determine system hostname: %m");
p = h;
r = dns_label_unescape(&p, label, sizeof label);
if (r < 0)
return log_error_errno(r, "Failed to unescape host name: %m");
if (r == 0) {
log_error("Couldn't find a single label in hostname.");
return -EINVAL;
}
#if HAVE_LIBIDN2
r = idn2_to_unicode_8z8z(label, &utf8, 0);
if (r != IDN2_OK)
return log_error("Failed to undo IDNA: %s", idn2_strerror(r));
assert(utf8_is_valid(utf8));
r = strlen(utf8);
decoded = utf8;
#elif HAVE_LIBIDN
k = dns_label_undo_idna(label, r, label, sizeof label);
if (k < 0)
return log_error_errno(k, "Failed to undo IDNA: %m");
if (k > 0)
r = k;
if (!utf8_is_valid(label)) {
log_error("System hostname is not UTF-8 clean.");
return -EINVAL;
}
decoded = label;
#else
decoded = label; /* no decoding */
#endif
r = dns_label_escape_new(decoded, r, &n);
if (r < 0)
return log_error_errno(r, "Failed to escape host name: %m");
if (is_localhost(n)) {
log_debug("System hostname is 'localhost', ignoring.");
return -EINVAL;
}
r = dns_name_concat(n, "local", mdns_hostname);
if (r < 0)
return log_error_errno(r, "Failed to determine mDNS hostname: %m");
*llmnr_hostname = TAKE_PTR(n);
*full_hostname = TAKE_PTR(h);
return 0;
}
static const char *fallback_hostname(void) {
/* Determine the fall back hostname. For exposing this system to the outside world, we cannot have it to be
* "localhost" even if that's the compiled in hostname. In this case, let's revert to "linux" instead. */
if (is_localhost(FALLBACK_HOSTNAME))
return "linux";
return FALLBACK_HOSTNAME;
}
static int make_fallback_hostnames(char **full_hostname, char **llmnr_hostname, char **mdns_hostname) {
_cleanup_free_ char *n = NULL, *m = NULL;
char label[DNS_LABEL_MAX], *h;
const char *p;
int r;
assert(full_hostname);
assert(llmnr_hostname);
assert(mdns_hostname);
p = fallback_hostname();
r = dns_label_unescape(&p, label, sizeof(label));
if (r < 0)
return log_error_errno(r, "Failed to unescape fallback host name: %m");
assert(r > 0); /* The fallback hostname must have at least one label */
r = dns_label_escape_new(label, r, &n);
if (r < 0)
return log_error_errno(r, "Failed to escape fallback hostname: %m");
r = dns_name_concat(n, "local", &m);
if (r < 0)
return log_error_errno(r, "Failed to concatenate mDNS hostname: %m");
h = strdup(fallback_hostname());
if (!h)
return log_oom();
*llmnr_hostname = TAKE_PTR(n);
*mdns_hostname = TAKE_PTR(m);
*full_hostname = h;
return 0;
}
static int on_hostname_change(sd_event_source *es, int fd, uint32_t revents, void *userdata) {
_cleanup_free_ char *full_hostname = NULL, *llmnr_hostname = NULL, *mdns_hostname = NULL;
Manager *m = userdata;
int r;
assert(m);
r = determine_hostname(&full_hostname, &llmnr_hostname, &mdns_hostname);
if (r < 0)
return 0; /* ignore invalid hostnames */
if (streq(full_hostname, m->full_hostname) &&
streq(llmnr_hostname, m->llmnr_hostname) &&
streq(mdns_hostname, m->mdns_hostname))
return 0;
log_info("System hostname changed to '%s'.", full_hostname);
free_and_replace(m->full_hostname, full_hostname);
free_and_replace(m->llmnr_hostname, llmnr_hostname);
free_and_replace(m->mdns_hostname, mdns_hostname);
manager_refresh_rrs(m);
return 0;
}
static int manager_watch_hostname(Manager *m) {
int r;
assert(m);
m->hostname_fd = open("/proc/sys/kernel/hostname",
O_RDONLY|O_CLOEXEC|O_NONBLOCK|O_NOCTTY);
if (m->hostname_fd < 0) {
log_warning_errno(errno, "Failed to watch hostname: %m");
return 0;
}
r = sd_event_add_io(m->event, &m->hostname_event_source, m->hostname_fd, 0, on_hostname_change, m);
if (r < 0) {
if (r == -EPERM)
/* kernels prior to 3.2 don't support polling this file. Ignore the failure. */
m->hostname_fd = safe_close(m->hostname_fd);
else
return log_error_errno(r, "Failed to add hostname event source: %m");
}
(void) sd_event_source_set_description(m->hostname_event_source, "hostname");
r = determine_hostname(&m->full_hostname, &m->llmnr_hostname, &m->mdns_hostname);
if (r < 0) {
log_info("Defaulting to hostname '%s'.", fallback_hostname());
r = make_fallback_hostnames(&m->full_hostname, &m->llmnr_hostname, &m->mdns_hostname);
if (r < 0)
return r;
} else
log_info("Using system hostname '%s'.", m->full_hostname);
return 0;
}
static int manager_sigusr1(sd_event_source *s, const struct signalfd_siginfo *si, void *userdata) {
_cleanup_free_ char *buffer = NULL;
_cleanup_fclose_ FILE *f = NULL;
Manager *m = userdata;
DnsServer *server;
size_t size = 0;
DnsScope *scope;
Iterator i;
Link *l;
assert(s);
assert(si);
assert(m);
f = open_memstream(&buffer, &size);
if (!f)
return log_oom();
(void) __fsetlocking(f, FSETLOCKING_BYCALLER);
LIST_FOREACH(scopes, scope, m->dns_scopes)
dns_scope_dump(scope, f);
LIST_FOREACH(servers, server, m->dns_servers)
dns_server_dump(server, f);
LIST_FOREACH(servers, server, m->fallback_dns_servers)
dns_server_dump(server, f);
HASHMAP_FOREACH(l, m->links, i)
LIST_FOREACH(servers, server, l->dns_servers)
dns_server_dump(server, f);
if (fflush_and_check(f) < 0)
return log_oom();
log_dump(LOG_INFO, buffer);
return 0;
}
static int manager_sigusr2(sd_event_source *s, const struct signalfd_siginfo *si, void *userdata) {
Manager *m = userdata;
assert(s);
assert(si);
assert(m);
manager_flush_caches(m);
return 0;
}
static int manager_sigrtmin1(sd_event_source *s, const struct signalfd_siginfo *si, void *userdata) {
Manager *m = userdata;
assert(s);
assert(si);
assert(m);
manager_reset_server_features(m);
return 0;
}
int manager_new(Manager **ret) {
_cleanup_(manager_freep) Manager *m = NULL;
int r;
assert(ret);
m = new0(Manager, 1);
if (!m)
return -ENOMEM;
m->llmnr_ipv4_udp_fd = m->llmnr_ipv6_udp_fd = -1;
m->llmnr_ipv4_tcp_fd = m->llmnr_ipv6_tcp_fd = -1;
m->mdns_ipv4_fd = m->mdns_ipv6_fd = -1;
m->dns_stub_udp_fd = m->dns_stub_tcp_fd = -1;
m->hostname_fd = -1;
m->llmnr_support = RESOLVE_SUPPORT_YES;
m->mdns_support = RESOLVE_SUPPORT_YES;
m->dnssec_mode = DEFAULT_DNSSEC_MODE;
m->enable_cache = true;
m->dns_stub_listener_mode = DNS_STUB_LISTENER_UDP;
m->read_resolv_conf = true;
m->need_builtin_fallbacks = true;
m->etc_hosts_last = m->etc_hosts_mtime = USEC_INFINITY;
r = dns_trust_anchor_load(&m->trust_anchor);
if (r < 0)
return r;
r = manager_parse_config_file(m);
if (r < 0)
log_warning_errno(r, "Failed to parse configuration file: %m");
r = sd_event_default(&m->event);
if (r < 0)
return r;
sd_event_add_signal(m->event, NULL, SIGTERM, NULL, NULL);
sd_event_add_signal(m->event, NULL, SIGINT, NULL, NULL);
sd_event_set_watchdog(m->event, true);
r = manager_watch_hostname(m);
if (r < 0)
return r;
r = dnssd_load(m);
if (r < 0)
log_warning_errno(r, "Failed to load DNS-SD configuration files: %m");
r = dns_scope_new(m, &m->unicast_scope, NULL, DNS_PROTOCOL_DNS, AF_UNSPEC);
if (r < 0)
return r;
r = manager_network_monitor_listen(m);
if (r < 0)
return r;
r = manager_rtnl_listen(m);
if (r < 0)
return r;
r = manager_connect_bus(m);
if (r < 0)
return r;
(void) sd_event_add_signal(m->event, &m->sigusr1_event_source, SIGUSR1, manager_sigusr1, m);
(void) sd_event_add_signal(m->event, &m->sigusr2_event_source, SIGUSR2, manager_sigusr2, m);
(void) sd_event_add_signal(m->event, &m->sigrtmin1_event_source, SIGRTMIN+1, manager_sigrtmin1, m);
manager_cleanup_saved_user(m);
*ret = m;
m = NULL;
return 0;
}
int manager_start(Manager *m) {
int r;
assert(m);
r = manager_dns_stub_start(m);
if (r < 0)
return r;
return 0;
}
Manager *manager_free(Manager *m) {
Link *l;
DnssdService *s;
if (!m)
return NULL;
dns_server_unlink_all(m->dns_servers);
dns_server_unlink_all(m->fallback_dns_servers);
dns_search_domain_unlink_all(m->search_domains);
while ((l = hashmap_first(m->links)))
link_free(l);
while (m->dns_queries)
dns_query_free(m->dns_queries);
dns_scope_free(m->unicast_scope);
/* At this point only orphaned streams should remain. All others should have been freed already by their
* owners */
while (m->dns_streams)
dns_stream_unref(m->dns_streams);
hashmap_free(m->links);
hashmap_free(m->dns_transactions);
sd_event_source_unref(m->network_event_source);
sd_network_monitor_unref(m->network_monitor);
sd_netlink_unref(m->rtnl);
sd_event_source_unref(m->rtnl_event_source);
manager_llmnr_stop(m);
manager_mdns_stop(m);
manager_dns_stub_stop(m);
sd_bus_slot_unref(m->prepare_for_sleep_slot);
sd_event_source_unref(m->bus_retry_event_source);
sd_bus_unref(m->bus);
sd_event_source_unref(m->sigusr1_event_source);
sd_event_source_unref(m->sigusr2_event_source);
sd_event_source_unref(m->sigrtmin1_event_source);
sd_event_unref(m->event);
dns_resource_key_unref(m->llmnr_host_ipv4_key);
dns_resource_key_unref(m->llmnr_host_ipv6_key);
dns_resource_key_unref(m->mdns_host_ipv4_key);
dns_resource_key_unref(m->mdns_host_ipv6_key);
sd_event_source_unref(m->hostname_event_source);
safe_close(m->hostname_fd);
free(m->full_hostname);
free(m->llmnr_hostname);
free(m->mdns_hostname);
while ((s = hashmap_first(m->dnssd_services)))
dnssd_service_free(s);
hashmap_free(m->dnssd_services);
dns_trust_anchor_flush(&m->trust_anchor);
manager_etc_hosts_flush(m);
return mfree(m);
}
int manager_recv(Manager *m, int fd, DnsProtocol protocol, DnsPacket **ret) {
_cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
union {
struct cmsghdr header; /* For alignment */
uint8_t buffer[CMSG_SPACE(MAXSIZE(struct in_pktinfo, struct in6_pktinfo))
+ CMSG_SPACE(int) /* ttl/hoplimit */
+ EXTRA_CMSG_SPACE /* kernel appears to require extra buffer space */];
} control;
union sockaddr_union sa;
struct msghdr mh = {};
struct cmsghdr *cmsg;
struct iovec iov;
ssize_t ms, l;
int r;
assert(m);
assert(fd >= 0);
assert(ret);
ms = next_datagram_size_fd(fd);
if (ms < 0)
return ms;
r = dns_packet_new(&p, protocol, ms, DNS_PACKET_SIZE_MAX);
if (r < 0)
return r;
iov.iov_base = DNS_PACKET_DATA(p);
iov.iov_len = p->allocated;
mh.msg_name = &sa.sa;
mh.msg_namelen = sizeof(sa);
mh.msg_iov = &iov;
mh.msg_iovlen = 1;
mh.msg_control = &control;
mh.msg_controllen = sizeof(control);
l = recvmsg(fd, &mh, 0);
if (l == 0)
return 0;
if (l < 0) {
if (IN_SET(errno, EAGAIN, EINTR))
return 0;
return -errno;
}
assert(!(mh.msg_flags & MSG_CTRUNC));
assert(!(mh.msg_flags & MSG_TRUNC));
p->size = (size_t) l;
p->family = sa.sa.sa_family;
p->ipproto = IPPROTO_UDP;
if (p->family == AF_INET) {
p->sender.in = sa.in.sin_addr;
p->sender_port = be16toh(sa.in.sin_port);
} else if (p->family == AF_INET6) {
p->sender.in6 = sa.in6.sin6_addr;
p->sender_port = be16toh(sa.in6.sin6_port);
p->ifindex = sa.in6.sin6_scope_id;
} else
return -EAFNOSUPPORT;
CMSG_FOREACH(cmsg, &mh) {
if (cmsg->cmsg_level == IPPROTO_IPV6) {
assert(p->family == AF_INET6);
switch (cmsg->cmsg_type) {
case IPV6_PKTINFO: {
struct in6_pktinfo *i = (struct in6_pktinfo*) CMSG_DATA(cmsg);
if (p->ifindex <= 0)
p->ifindex = i->ipi6_ifindex;
p->destination.in6 = i->ipi6_addr;
break;
}
case IPV6_HOPLIMIT:
p->ttl = *(int *) CMSG_DATA(cmsg);
break;
}
} else if (cmsg->cmsg_level == IPPROTO_IP) {
assert(p->family == AF_INET);
switch (cmsg->cmsg_type) {
case IP_PKTINFO: {
struct in_pktinfo *i = (struct in_pktinfo*) CMSG_DATA(cmsg);
if (p->ifindex <= 0)
p->ifindex = i->ipi_ifindex;
p->destination.in = i->ipi_addr;
break;
}
case IP_TTL:
p->ttl = *(int *) CMSG_DATA(cmsg);
break;
}
}
}
/* The Linux kernel sets the interface index to the loopback
* device if the packet came from the local host since it
* avoids the routing table in such a case. Let's unset the
* interface index in such a case. */
if (p->ifindex == LOOPBACK_IFINDEX)
p->ifindex = 0;
if (protocol != DNS_PROTOCOL_DNS) {
/* If we don't know the interface index still, we look for the
* first local interface with a matching address. Yuck! */
if (p->ifindex <= 0)
p->ifindex = manager_find_ifindex(m, p->family, &p->destination);
}
*ret = p;
p = NULL;
return 1;
}
static int sendmsg_loop(int fd, struct msghdr *mh, int flags) {
int r;
assert(fd >= 0);
assert(mh);
for (;;) {
if (sendmsg(fd, mh, flags) >= 0)
return 0;
if (errno == EINTR)
continue;
if (errno != EAGAIN)
return -errno;
r = fd_wait_for_event(fd, POLLOUT, SEND_TIMEOUT_USEC);
if (r < 0)
return r;
if (r == 0)
return -ETIMEDOUT;
}
}
static int write_loop(int fd, void *message, size_t length) {
int r;
assert(fd >= 0);
assert(message);
for (;;) {
if (write(fd, message, length) >= 0)
return 0;
if (errno == EINTR)
continue;
if (errno != EAGAIN)
return -errno;
r = fd_wait_for_event(fd, POLLOUT, SEND_TIMEOUT_USEC);
if (r < 0)
return r;
if (r == 0)
return -ETIMEDOUT;
}
}
int manager_write(Manager *m, int fd, DnsPacket *p) {
int r;
log_debug("Sending %s packet with id %" PRIu16 ".", DNS_PACKET_QR(p) ? "response" : "query", DNS_PACKET_ID(p));
r = write_loop(fd, DNS_PACKET_DATA(p), p->size);
if (r < 0)
return r;
return 0;
}
static int manager_ipv4_send(
Manager *m,
int fd,
int ifindex,
const struct in_addr *destination,
uint16_t port,
const struct in_addr *source,
DnsPacket *p) {
union sockaddr_union sa = {
.in.sin_family = AF_INET,
};
union {
struct cmsghdr header; /* For alignment */
uint8_t buffer[CMSG_SPACE(sizeof(struct in_pktinfo))];
} control;
struct msghdr mh = {};
struct iovec iov;
assert(m);
assert(fd >= 0);
assert(destination);
assert(port > 0);
assert(p);
iov.iov_base = DNS_PACKET_DATA(p);
iov.iov_len = p->size;
sa.in.sin_addr = *destination;
sa.in.sin_port = htobe16(port),
mh.msg_iov = &iov;
mh.msg_iovlen = 1;
mh.msg_name = &sa.sa;
mh.msg_namelen = sizeof(sa.in);
if (ifindex > 0) {
struct cmsghdr *cmsg;
struct in_pktinfo *pi;
zero(control);
mh.msg_control = &control;
mh.msg_controllen = CMSG_LEN(sizeof(struct in_pktinfo));
cmsg = CMSG_FIRSTHDR(&mh);
cmsg->cmsg_len = mh.msg_controllen;
cmsg->cmsg_level = IPPROTO_IP;
cmsg->cmsg_type = IP_PKTINFO;
pi = (struct in_pktinfo*) CMSG_DATA(cmsg);
pi->ipi_ifindex = ifindex;
if (source)
pi->ipi_spec_dst = *source;
}
return sendmsg_loop(fd, &mh, 0);
}
static int manager_ipv6_send(
Manager *m,
int fd,
int ifindex,
const struct in6_addr *destination,
uint16_t port,
const struct in6_addr *source,
DnsPacket *p) {
union sockaddr_union sa = {
.in6.sin6_family = AF_INET6,
};
union {
struct cmsghdr header; /* For alignment */
uint8_t buffer[CMSG_SPACE(sizeof(struct in6_pktinfo))];
} control;
struct msghdr mh = {};
struct iovec iov;
assert(m);
assert(fd >= 0);
assert(destination);
assert(port > 0);
assert(p);
iov.iov_base = DNS_PACKET_DATA(p);
iov.iov_len = p->size;
sa.in6.sin6_addr = *destination;
sa.in6.sin6_port = htobe16(port),
sa.in6.sin6_scope_id = ifindex;
mh.msg_iov = &iov;
mh.msg_iovlen = 1;
mh.msg_name = &sa.sa;
mh.msg_namelen = sizeof(sa.in6);
if (ifindex > 0) {
struct cmsghdr *cmsg;
struct in6_pktinfo *pi;
zero(control);
mh.msg_control = &control;
mh.msg_controllen = CMSG_LEN(sizeof(struct in6_pktinfo));
cmsg = CMSG_FIRSTHDR(&mh);
cmsg->cmsg_len = mh.msg_controllen;
cmsg->cmsg_level = IPPROTO_IPV6;
cmsg->cmsg_type = IPV6_PKTINFO;
pi = (struct in6_pktinfo*) CMSG_DATA(cmsg);
pi->ipi6_ifindex = ifindex;
if (source)
pi->ipi6_addr = *source;
}
return sendmsg_loop(fd, &mh, 0);
}
int manager_send(
Manager *m,
int fd,
int ifindex,
int family,
const union in_addr_union *destination,
uint16_t port,
const union in_addr_union *source,
DnsPacket *p) {
assert(m);
assert(fd >= 0);
assert(destination);
assert(port > 0);
assert(p);
log_debug("Sending %s packet with id %" PRIu16 " on interface %i/%s.", DNS_PACKET_QR(p) ? "response" : "query", DNS_PACKET_ID(p), ifindex, af_to_name(family));
if (family == AF_INET)
return manager_ipv4_send(m, fd, ifindex, &destination->in, port, &source->in, p);
if (family == AF_INET6)
return manager_ipv6_send(m, fd, ifindex, &destination->in6, port, &source->in6, p);
return -EAFNOSUPPORT;
}
uint32_t manager_find_mtu(Manager *m) {
uint32_t mtu = 0;
Link *l;
Iterator i;
/* If we don't know on which link a DNS packet would be
* delivered, let's find the largest MTU that works on all
* interfaces we know of */
HASHMAP_FOREACH(l, m->links, i) {
if (l->mtu <= 0)
continue;
if (mtu <= 0 || l->mtu < mtu)
mtu = l->mtu;
}
return mtu;
}
int manager_find_ifindex(Manager *m, int family, const union in_addr_union *in_addr) {
LinkAddress *a;
assert(m);
a = manager_find_link_address(m, family, in_addr);
if (a)
return a->link->ifindex;
return 0;
}
void manager_refresh_rrs(Manager *m) {
Iterator i;
Link *l;
DnssdService *s;
assert(m);
m->llmnr_host_ipv4_key = dns_resource_key_unref(m->llmnr_host_ipv4_key);
m->llmnr_host_ipv6_key = dns_resource_key_unref(m->llmnr_host_ipv6_key);
m->mdns_host_ipv4_key = dns_resource_key_unref(m->mdns_host_ipv4_key);
m->mdns_host_ipv6_key = dns_resource_key_unref(m->mdns_host_ipv6_key);
if (m->mdns_support == RESOLVE_SUPPORT_YES)
HASHMAP_FOREACH(s, m->dnssd_services, i)
if (dnssd_update_rrs(s) < 0)
log_warning("Failed to refresh DNS-SD service '%s'", s->name);
HASHMAP_FOREACH(l, m->links, i) {
link_add_rrs(l, true);
link_add_rrs(l, false);
}
}
static int manager_next_random_name(const char *old, char **ret_new) {
const char *p;
uint64_t u, a;
char *n;
p = strchr(old, 0);
assert(p);
while (p > old) {
if (!strchr(DIGITS, p[-1]))
break;
p--;
}
if (*p == 0 || safe_atou64(p, &u) < 0 || u <= 0)
u = 1;
/* Add a random number to the old value. This way we can avoid
* that two hosts pick the same hostname, win on IPv4 and lose
* on IPv6 (or vice versa), and pick the same hostname
* replacement hostname, ad infinitum. We still want the
* numbers to go up monotonically, hence we just add a random
* value 1..10 */
random_bytes(&a, sizeof(a));
u += 1 + a % 10;
if (asprintf(&n, "%.*s%" PRIu64, (int) (p - old), old, u) < 0)
return -ENOMEM;
*ret_new = n;
return 0;
}
int manager_next_hostname(Manager *m) {
_cleanup_free_ char *h = NULL, *k = NULL;
int r;
assert(m);
r = manager_next_random_name(m->llmnr_hostname, &h);
if (r < 0)
return r;
r = dns_name_concat(h, "local", &k);
if (r < 0)
return r;
log_info("Hostname conflict, changing published hostname from '%s' to '%s'.", m->llmnr_hostname, h);
free_and_replace(m->llmnr_hostname, h);
free_and_replace(m->mdns_hostname, k);
manager_refresh_rrs(m);
return 0;
}
LinkAddress* manager_find_link_address(Manager *m, int family, const union in_addr_union *in_addr) {
Iterator i;
Link *l;
assert(m);
HASHMAP_FOREACH(l, m->links, i) {
LinkAddress *a;
a = link_find_address(l, family, in_addr);
if (a)
return a;
}
return NULL;
}
bool manager_our_packet(Manager *m, DnsPacket *p) {
assert(m);
assert(p);
return !!manager_find_link_address(m, p->family, &p->sender);
}
DnsScope* manager_find_scope(Manager *m, DnsPacket *p) {
Link *l;
assert(m);
assert(p);
l = hashmap_get(m->links, INT_TO_PTR(p->ifindex));
if (!l)
return NULL;
switch (p->protocol) {
case DNS_PROTOCOL_LLMNR:
if (p->family == AF_INET)
return l->llmnr_ipv4_scope;
else if (p->family == AF_INET6)
return l->llmnr_ipv6_scope;
break;
case DNS_PROTOCOL_MDNS:
if (p->family == AF_INET)
return l->mdns_ipv4_scope;
else if (p->family == AF_INET6)
return l->mdns_ipv6_scope;
break;
default:
break;
}
return NULL;
}
void manager_verify_all(Manager *m) {
DnsScope *s;
assert(m);
LIST_FOREACH(scopes, s, m->dns_scopes)
dns_zone_verify_all(&s->zone);
}
int manager_is_own_hostname(Manager *m, const char *name) {
int r;
assert(m);
assert(name);
if (m->llmnr_hostname) {
r = dns_name_equal(name, m->llmnr_hostname);
if (r != 0)
return r;
}
if (m->mdns_hostname) {
r = dns_name_equal(name, m->mdns_hostname);
if (r != 0)
return r;
}
if (m->full_hostname)
return dns_name_equal(name, m->full_hostname);
return 0;
}
int manager_compile_dns_servers(Manager *m, OrderedSet **dns) {
DnsServer *s;
Iterator i;
Link *l;
int r;
assert(m);
assert(dns);
r = ordered_set_ensure_allocated(dns, &dns_server_hash_ops);
if (r < 0)
return r;
/* First add the system-wide servers and domains */
LIST_FOREACH(servers, s, m->dns_servers) {
r = ordered_set_put(*dns, s);
if (r == -EEXIST)
continue;
if (r < 0)
return r;
}
/* Then, add the per-link servers */
HASHMAP_FOREACH(l, m->links, i) {
LIST_FOREACH(servers, s, l->dns_servers) {
r = ordered_set_put(*dns, s);
if (r == -EEXIST)
continue;
if (r < 0)
return r;
}
}
/* If we found nothing, add the fallback servers */
if (ordered_set_isempty(*dns)) {
LIST_FOREACH(servers, s, m->fallback_dns_servers) {
r = ordered_set_put(*dns, s);
if (r == -EEXIST)
continue;
if (r < 0)
return r;
}
}
return 0;
}
/* filter_route is a tri-state:
* < 0: no filtering
* = 0 or false: return only domains which should be used for searching
* > 0 or true: return only domains which are for routing only
*/
int manager_compile_search_domains(Manager *m, OrderedSet **domains, int filter_route) {
DnsSearchDomain *d;
Iterator i;
Link *l;
int r;
assert(m);
assert(domains);
r = ordered_set_ensure_allocated(domains, &dns_name_hash_ops);
if (r < 0)
return r;
LIST_FOREACH(domains, d, m->search_domains) {
if (filter_route >= 0 &&
d->route_only != !!filter_route)
continue;
r = ordered_set_put(*domains, d->name);
if (r == -EEXIST)
continue;
if (r < 0)
return r;
}
HASHMAP_FOREACH(l, m->links, i) {
LIST_FOREACH(domains, d, l->search_domains) {
if (filter_route >= 0 &&
d->route_only != !!filter_route)
continue;
r = ordered_set_put(*domains, d->name);
if (r == -EEXIST)
continue;
if (r < 0)
return r;
}
}
return 0;
}
DnssecMode manager_get_dnssec_mode(Manager *m) {
assert(m);
if (m->dnssec_mode != _DNSSEC_MODE_INVALID)
return m->dnssec_mode;
return DNSSEC_NO;
}
bool manager_dnssec_supported(Manager *m) {
DnsServer *server;
Iterator i;
Link *l;
assert(m);
if (manager_get_dnssec_mode(m) == DNSSEC_NO)
return false;
server = manager_get_dns_server(m);
if (server && !dns_server_dnssec_supported(server))
return false;
HASHMAP_FOREACH(l, m->links, i)
if (!link_dnssec_supported(l))
return false;
return true;
}
void manager_dnssec_verdict(Manager *m, DnssecVerdict verdict, const DnsResourceKey *key) {
assert(verdict >= 0);
assert(verdict < _DNSSEC_VERDICT_MAX);
if (DEBUG_LOGGING) {
char s[DNS_RESOURCE_KEY_STRING_MAX];
log_debug("Found verdict for lookup %s: %s",
dns_resource_key_to_string(key, s, sizeof s),
dnssec_verdict_to_string(verdict));
}
m->n_dnssec_verdict[verdict]++;
}
bool manager_routable(Manager *m, int family) {
Iterator i;
Link *l;
assert(m);
/* Returns true if the host has at least one interface with a routable address of the specified type */
HASHMAP_FOREACH(l, m->links, i)
if (link_relevant(l, family, false))
return true;
return false;
}
void manager_flush_caches(Manager *m) {
DnsScope *scope;
assert(m);
LIST_FOREACH(scopes, scope, m->dns_scopes)
dns_cache_flush(&scope->cache);
log_info("Flushed all caches.");
}
void manager_reset_server_features(Manager *m) {
Iterator i;
Link *l;
dns_server_reset_features_all(m->dns_servers);
dns_server_reset_features_all(m->fallback_dns_servers);
HASHMAP_FOREACH(l, m->links, i)
dns_server_reset_features_all(l->dns_servers);
log_info("Resetting learnt feature levels on all servers.");
}
void manager_cleanup_saved_user(Manager *m) {
_cleanup_closedir_ DIR *d = NULL;
struct dirent *de;
int r;
assert(m);
/* Clean up all saved per-link files in /run/systemd/resolve/netif/ that don't have a matching interface
* anymore. These files are created to persist settings pushed in by the user via the bus, so that resolved can
* be restarted without losing this data. */
d = opendir("/run/systemd/resolve/netif/");
if (!d) {
if (errno == ENOENT)
return;
log_warning_errno(errno, "Failed to open interface directory: %m");
return;
}
FOREACH_DIRENT_ALL(de, d, log_error_errno(errno, "Failed to read interface directory: %m")) {
_cleanup_free_ char *p = NULL;
int ifindex;
Link *l;
if (!IN_SET(de->d_type, DT_UNKNOWN, DT_REG))
continue;
if (dot_or_dot_dot(de->d_name))
continue;
r = parse_ifindex(de->d_name, &ifindex);
if (r < 0) /* Probably some temporary file from a previous run. Delete it */
goto rm;
l = hashmap_get(m->links, INT_TO_PTR(ifindex));
if (!l) /* link vanished */
goto rm;
if (l->is_managed) /* now managed by networkd, hence the bus settings are useless */
goto rm;
continue;
rm:
p = strappend("/run/systemd/resolve/netif/", de->d_name);
if (!p) {
log_oom();
return;
}
(void) unlink(p);
}
}
bool manager_next_dnssd_names(Manager *m) {
Iterator i;
DnssdService *s;
bool tried = false;
int r;
assert(m);
HASHMAP_FOREACH(s, m->dnssd_services, i) {
_cleanup_free_ char * new_name = NULL;
if (!s->withdrawn)
continue;
r = manager_next_random_name(s->name_template, &new_name);
if (r < 0) {
log_warning_errno(r, "Failed to get new name for service '%s': %m", s->name);
continue;
}
free_and_replace(s->name_template, new_name);
s->withdrawn = false;
tried = true;
}
if (tried)
manager_refresh_rrs(m);
return tried;
}
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