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systemd/src/resolve/resolved-link.c
Luca Boccassi 14a5217679 resolved: support reloading configuration at runtime 
Drop connections and caches and reload config from files, to allow
for low-interruptions updates, and hook up to the usual SIGHUP and
ExecReload=. Mark servers and services configured directly via D-Bus
so that they can be kept around, and only the configuration file
settings are dropped and reloaded.

Fixes https://github.com/systemd/systemd/issues/17503
Fixes https://github.com/systemd/systemd/issues/20604
2024-03-26 13:36:42 +00:00

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/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include <linux/if.h>
#include <unistd.h>
#include "sd-network.h"
#include "alloc-util.h"
#include "env-file.h"
#include "fd-util.h"
#include "fileio.h"
#include "fs-util.h"
#include "log-link.h"
#include "mkdir.h"
#include "netif-util.h"
#include "parse-util.h"
#include "resolved-link.h"
#include "resolved-llmnr.h"
#include "resolved-mdns.h"
#include "socket-netlink.h"
#include "stat-util.h"
#include "string-util.h"
#include "strv.h"
#include "tmpfile-util.h"
int link_new(Manager *m, Link **ret, int ifindex) {
_cleanup_(link_freep) Link *l = NULL;
int r;
assert(m);
assert(ifindex > 0);
l = new(Link, 1);
if (!l)
return -ENOMEM;
*l = (Link) {
.ifindex = ifindex,
.default_route = -1,
.llmnr_support = RESOLVE_SUPPORT_YES,
.mdns_support = RESOLVE_SUPPORT_YES,
.dnssec_mode = _DNSSEC_MODE_INVALID,
.dns_over_tls_mode = _DNS_OVER_TLS_MODE_INVALID,
.operstate = IF_OPER_UNKNOWN,
};
if (asprintf(&l->state_file, "/run/systemd/resolve/netif/%i", ifindex) < 0)
return -ENOMEM;
r = hashmap_ensure_put(&m->links, NULL, INT_TO_PTR(ifindex), l);
if (r < 0)
return r;
l->manager = m;
if (ret)
*ret = l;
TAKE_PTR(l);
return 0;
}
void link_flush_settings(Link *l) {
assert(l);
l->default_route = -1;
l->llmnr_support = RESOLVE_SUPPORT_YES;
l->mdns_support = RESOLVE_SUPPORT_YES;
l->dnssec_mode = _DNSSEC_MODE_INVALID;
l->dns_over_tls_mode = _DNS_OVER_TLS_MODE_INVALID;
dns_server_unlink_all(l->dns_servers);
dns_search_domain_unlink_all(l->search_domains);
l->dnssec_negative_trust_anchors = set_free_free(l->dnssec_negative_trust_anchors);
}
Link *link_free(Link *l) {
if (!l)
return NULL;
/* Send goodbye messages. */
dns_scope_announce(l->mdns_ipv4_scope, true);
dns_scope_announce(l->mdns_ipv6_scope, true);
link_flush_settings(l);
while (l->addresses)
(void) link_address_free(l->addresses);
if (l->manager)
hashmap_remove(l->manager->links, INT_TO_PTR(l->ifindex));
dns_scope_free(l->unicast_scope);
dns_scope_free(l->llmnr_ipv4_scope);
dns_scope_free(l->llmnr_ipv6_scope);
dns_scope_free(l->mdns_ipv4_scope);
dns_scope_free(l->mdns_ipv6_scope);
free(l->state_file);
free(l->ifname);
return mfree(l);
}
void link_allocate_scopes(Link *l) {
bool unicast_relevant;
int r;
assert(l);
/* If a link that used to be relevant is no longer, or a link that did not use to be relevant now becomes
* relevant, let's reinit the learnt global DNS server information, since we might talk to different servers
* now, even if they have the same addresses as before. */
unicast_relevant = link_relevant(l, AF_UNSPEC, false);
if (unicast_relevant != l->unicast_relevant) {
l->unicast_relevant = unicast_relevant;
dns_server_reset_features_all(l->manager->fallback_dns_servers);
dns_server_reset_features_all(l->manager->dns_servers);
/* Also, flush the global unicast scope, to deal with split horizon setups, where talking through one
* interface reveals different DNS zones than through others. */
if (l->manager->unicast_scope)
dns_cache_flush(&l->manager->unicast_scope->cache);
}
/* And now, allocate all scopes that makes sense now if we didn't have them yet, and drop those which we don't
* need anymore */
if (unicast_relevant && l->dns_servers) {
if (!l->unicast_scope) {
dns_server_reset_features_all(l->dns_servers);
r = dns_scope_new(l->manager, &l->unicast_scope, l, DNS_PROTOCOL_DNS, AF_UNSPEC);
if (r < 0)
log_link_warning_errno(l, r, "Failed to allocate DNS scope, ignoring: %m");
}
} else
l->unicast_scope = dns_scope_free(l->unicast_scope);
if (link_relevant(l, AF_INET, true) &&
link_get_llmnr_support(l) != RESOLVE_SUPPORT_NO) {
if (!l->llmnr_ipv4_scope) {
r = dns_scope_new(l->manager, &l->llmnr_ipv4_scope, l, DNS_PROTOCOL_LLMNR, AF_INET);
if (r < 0)
log_link_warning_errno(l, r, "Failed to allocate LLMNR IPv4 scope, ignoring: %m");
}
} else
l->llmnr_ipv4_scope = dns_scope_free(l->llmnr_ipv4_scope);
if (link_relevant(l, AF_INET6, true) &&
link_get_llmnr_support(l) != RESOLVE_SUPPORT_NO) {
if (!l->llmnr_ipv6_scope) {
r = dns_scope_new(l->manager, &l->llmnr_ipv6_scope, l, DNS_PROTOCOL_LLMNR, AF_INET6);
if (r < 0)
log_link_warning_errno(l, r, "Failed to allocate LLMNR IPv6 scope, ignoring: %m");
}
} else
l->llmnr_ipv6_scope = dns_scope_free(l->llmnr_ipv6_scope);
if (link_relevant(l, AF_INET, true) &&
link_get_mdns_support(l) != RESOLVE_SUPPORT_NO) {
if (!l->mdns_ipv4_scope) {
r = dns_scope_new(l->manager, &l->mdns_ipv4_scope, l, DNS_PROTOCOL_MDNS, AF_INET);
if (r < 0)
log_link_warning_errno(l, r, "Failed to allocate mDNS IPv4 scope, ignoring: %m");
}
} else
l->mdns_ipv4_scope = dns_scope_free(l->mdns_ipv4_scope);
if (link_relevant(l, AF_INET6, true) &&
link_get_mdns_support(l) != RESOLVE_SUPPORT_NO) {
if (!l->mdns_ipv6_scope) {
r = dns_scope_new(l->manager, &l->mdns_ipv6_scope, l, DNS_PROTOCOL_MDNS, AF_INET6);
if (r < 0)
log_link_warning_errno(l, r, "Failed to allocate mDNS IPv6 scope, ignoring: %m");
}
} else
l->mdns_ipv6_scope = dns_scope_free(l->mdns_ipv6_scope);
}
void link_add_rrs(Link *l, bool force_remove) {
int r;
LIST_FOREACH(addresses, a, l->addresses)
link_address_add_rrs(a, force_remove);
if (!force_remove &&
link_get_mdns_support(l) == RESOLVE_SUPPORT_YES) {
if (l->mdns_ipv4_scope) {
r = dns_scope_add_dnssd_services(l->mdns_ipv4_scope);
if (r < 0)
log_link_warning_errno(l, r, "Failed to add IPv4 DNS-SD services, ignoring: %m");
}
if (l->mdns_ipv6_scope) {
r = dns_scope_add_dnssd_services(l->mdns_ipv6_scope);
if (r < 0)
log_link_warning_errno(l, r, "Failed to add IPv6 DNS-SD services, ignoring: %m");
}
} else {
if (l->mdns_ipv4_scope) {
r = dns_scope_remove_dnssd_services(l->mdns_ipv4_scope);
if (r < 0)
log_link_warning_errno(l, r, "Failed to remove IPv4 DNS-SD services, ignoring: %m");
}
if (l->mdns_ipv6_scope) {
r = dns_scope_remove_dnssd_services(l->mdns_ipv6_scope);
if (r < 0)
log_link_warning_errno(l, r, "Failed to remove IPv6 DNS-SD services, ignoring: %m");
}
}
}
int link_process_rtnl(Link *l, sd_netlink_message *m) {
const char *n = NULL;
int r;
assert(l);
assert(m);
r = sd_rtnl_message_link_get_flags(m, &l->flags);
if (r < 0)
return r;
(void) sd_netlink_message_read_u32(m, IFLA_MTU, &l->mtu);
(void) sd_netlink_message_read_u8(m, IFLA_OPERSTATE, &l->operstate);
if (sd_netlink_message_read_string(m, IFLA_IFNAME, &n) >= 0 &&
!streq_ptr(l->ifname, n)) {
if (l->ifname)
log_link_debug(l, "Interface name change detected: %s -> %s", l->ifname, n);
r = free_and_strdup(&l->ifname, n);
if (r < 0)
return r;
}
return 0;
}
static int link_update_dns_server_one(Link *l, const char *str) {
_cleanup_free_ char *name = NULL;
int family, ifindex, r;
union in_addr_union a;
DnsServer *s;
uint16_t port;
assert(l);
assert(str);
r = in_addr_port_ifindex_name_from_string_auto(str, &family, &a, &port, &ifindex, &name);
if (r < 0)
return r;
if (ifindex != 0 && ifindex != l->ifindex)
return -EINVAL;
/* By default, the port number is determined with the transaction feature level.
* See dns_transaction_port() and dns_server_port(). */
if (IN_SET(port, 53, 853))
port = 0;
s = dns_server_find(l->dns_servers, family, &a, port, 0, name);
if (s) {
dns_server_move_back_and_unmark(s);
return 0;
}
return dns_server_new(l->manager, NULL, DNS_SERVER_LINK, l, family, &a, port, 0, name, RESOLVE_CONFIG_SOURCE_NETWORKD);
}
static int link_update_dns_servers(Link *l) {
_cleanup_strv_free_ char **nameservers = NULL;
int r;
assert(l);
r = sd_network_link_get_dns(l->ifindex, &nameservers);
if (r == -ENODATA) {
r = 0;
goto clear;
}
if (r < 0)
goto clear;
dns_server_mark_all(l->dns_servers);
STRV_FOREACH(nameserver, nameservers) {
r = link_update_dns_server_one(l, *nameserver);
if (r < 0)
goto clear;
}
dns_server_unlink_marked(l->dns_servers);
return 0;
clear:
dns_server_unlink_all(l->dns_servers);
return r;
}
static int link_update_default_route(Link *l) {
int r;
assert(l);
r = sd_network_link_get_dns_default_route(l->ifindex);
if (r == -ENODATA) {
r = 0;
goto clear;
}
if (r < 0)
goto clear;
l->default_route = r > 0;
return 0;
clear:
l->default_route = -1;
return r;
}
static int link_update_llmnr_support(Link *l) {
_cleanup_free_ char *b = NULL;
int r;
assert(l);
l->llmnr_support = RESOLVE_SUPPORT_YES; /* yes, yes, we set it twice which is ugly */
r = sd_network_link_get_llmnr(l->ifindex, &b);
if (r == -ENODATA)
return 0;
if (r < 0)
return r;
r = resolve_support_from_string(b);
if (r < 0)
return r;
l->llmnr_support = r;
return 0;
}
static int link_update_mdns_support(Link *l) {
_cleanup_free_ char *b = NULL;
int r;
assert(l);
l->mdns_support = RESOLVE_SUPPORT_YES;
r = sd_network_link_get_mdns(l->ifindex, &b);
if (r == -ENODATA)
return 0;
if (r < 0)
return r;
r = resolve_support_from_string(b);
if (r < 0)
return r;
l->mdns_support = r;
return 0;
}
void link_set_dns_over_tls_mode(Link *l, DnsOverTlsMode mode) {
assert(l);
#if ! ENABLE_DNS_OVER_TLS
if (mode != DNS_OVER_TLS_NO)
log_link_warning(l,
"DNS-over-TLS option for the link cannot be enabled or set to opportunistic "
"when systemd-resolved is built without DNS-over-TLS support. "
"Turning off DNS-over-TLS support.");
return;
#endif
l->dns_over_tls_mode = mode;
l->unicast_scope = dns_scope_free(l->unicast_scope);
}
static int link_update_dns_over_tls_mode(Link *l) {
_cleanup_free_ char *b = NULL;
int r;
assert(l);
l->dns_over_tls_mode = _DNS_OVER_TLS_MODE_INVALID;
r = sd_network_link_get_dns_over_tls(l->ifindex, &b);
if (r == -ENODATA)
return 0;
if (r < 0)
return r;
r = dns_over_tls_mode_from_string(b);
if (r < 0)
return r;
l->dns_over_tls_mode = r;
return 0;
}
void link_set_dnssec_mode(Link *l, DnssecMode mode) {
assert(l);
#if !HAVE_OPENSSL_OR_GCRYPT
if (IN_SET(mode, DNSSEC_YES, DNSSEC_ALLOW_DOWNGRADE))
log_link_warning(l,
"DNSSEC option for the link cannot be enabled or set to allow-downgrade "
"when systemd-resolved is built without a cryptographic library. "
"Turning off DNSSEC support.");
return;
#endif
if (l->dnssec_mode == mode)
return;
l->dnssec_mode = mode;
l->unicast_scope = dns_scope_free(l->unicast_scope);
}
static int link_update_dnssec_mode(Link *l) {
_cleanup_free_ char *m = NULL;
DnssecMode mode;
int r;
assert(l);
l->dnssec_mode = _DNSSEC_MODE_INVALID;
r = sd_network_link_get_dnssec(l->ifindex, &m);
if (r == -ENODATA)
return 0;
if (r < 0)
return r;
mode = dnssec_mode_from_string(m);
if (mode < 0)
return mode;
link_set_dnssec_mode(l, mode);
return 0;
}
static int link_update_dnssec_negative_trust_anchors(Link *l) {
_cleanup_strv_free_ char **ntas = NULL;
_cleanup_set_free_free_ Set *ns = NULL;
int r;
assert(l);
l->dnssec_negative_trust_anchors = set_free_free(l->dnssec_negative_trust_anchors);
r = sd_network_link_get_dnssec_negative_trust_anchors(l->ifindex, &ntas);
if (r == -ENODATA)
return 0;
if (r < 0)
return r;
ns = set_new(&dns_name_hash_ops);
if (!ns)
return -ENOMEM;
r = set_put_strdupv(&ns, ntas);
if (r < 0)
return r;
l->dnssec_negative_trust_anchors = TAKE_PTR(ns);
return 0;
}
static int link_update_search_domain_one(Link *l, const char *name, bool route_only) {
DnsSearchDomain *d;
int r;
assert(l);
assert(name);
r = dns_search_domain_find(l->search_domains, name, &d);
if (r < 0)
return r;
if (r > 0)
dns_search_domain_move_back_and_unmark(d);
else {
r = dns_search_domain_new(l->manager, &d, DNS_SEARCH_DOMAIN_LINK, l, name);
if (r < 0)
return r;
}
d->route_only = route_only;
return 0;
}
static int link_update_search_domains(Link *l) {
_cleanup_strv_free_ char **sdomains = NULL, **rdomains = NULL;
int r, q;
assert(l);
r = sd_network_link_get_search_domains(l->ifindex, &sdomains);
if (r < 0 && r != -ENODATA)
goto clear;
q = sd_network_link_get_route_domains(l->ifindex, &rdomains);
if (q < 0 && q != -ENODATA) {
r = q;
goto clear;
}
if (r == -ENODATA && q == -ENODATA) {
/* networkd knows nothing about this interface, and that's fine. */
r = 0;
goto clear;
}
dns_search_domain_mark_all(l->search_domains);
STRV_FOREACH(i, sdomains) {
r = link_update_search_domain_one(l, *i, false);
if (r < 0)
goto clear;
}
STRV_FOREACH(i, rdomains) {
r = link_update_search_domain_one(l, *i, true);
if (r < 0)
goto clear;
}
dns_search_domain_unlink_marked(l->search_domains);
return 0;
clear:
dns_search_domain_unlink_all(l->search_domains);
return r;
}
static int link_is_managed(Link *l) {
_cleanup_free_ char *state = NULL;
int r;
assert(l);
r = sd_network_link_get_setup_state(l->ifindex, &state);
if (r == -ENODATA)
return 0;
if (r < 0)
return r;
return !STR_IN_SET(state, "pending", "initialized", "unmanaged");
}
static void link_enter_unmanaged(Link *l) {
assert(l);
/* If this link used to be managed, but is now unmanaged, flush all our settings — but only once. */
if (l->is_managed)
link_flush_settings(l);
l->is_managed = false;
}
static void link_read_settings(Link *l) {
struct stat st;
int r;
assert(l);
/* Read settings from networkd, except when networkd is not managing this interface. */
r = sd_network_link_get_stat(l->ifindex, &st);
if (r == -ENOENT)
return link_enter_unmanaged(l);
if (r < 0)
return (void) log_link_warning_errno(l, r, "Failed to stat() networkd's link state file, ignoring: %m");
if (stat_inode_unmodified(&l->networkd_state_file_stat, &st))
/* The state file is unmodified. Not necessary to re-read settings. */
return;
/* Save the new stat for the next event. */
l->networkd_state_file_stat = st;
r = link_is_managed(l);
if (r < 0)
return (void) log_link_warning_errno(l, r, "Failed to determine whether the interface is managed, ignoring: %m");
if (r == 0)
return link_enter_unmanaged(l);
l->is_managed = true;
r = network_link_get_operational_state(l->ifindex, &l->networkd_operstate);
if (r < 0)
log_link_warning_errno(l, r, "Failed to read networkd's link operational state, ignoring: %m");
r = link_update_dns_servers(l);
if (r < 0)
log_link_warning_errno(l, r, "Failed to read DNS servers for the interface, ignoring: %m");
r = link_update_llmnr_support(l);
if (r < 0)
log_link_warning_errno(l, r, "Failed to read LLMNR support for the interface, ignoring: %m");
r = link_update_mdns_support(l);
if (r < 0)
log_link_warning_errno(l, r, "Failed to read mDNS support for the interface, ignoring: %m");
r = link_update_dns_over_tls_mode(l);
if (r < 0)
log_link_warning_errno(l, r, "Failed to read DNS-over-TLS mode for the interface, ignoring: %m");
r = link_update_dnssec_mode(l);
if (r < 0)
log_link_warning_errno(l, r, "Failed to read DNSSEC mode for the interface, ignoring: %m");
r = link_update_dnssec_negative_trust_anchors(l);
if (r < 0)
log_link_warning_errno(l, r, "Failed to read DNSSEC negative trust anchors for the interface, ignoring: %m");
r = link_update_search_domains(l);
if (r < 0)
log_link_warning_errno(l, r, "Failed to read search domains for the interface, ignoring: %m");
r = link_update_default_route(l);
if (r < 0)
log_link_warning_errno(l, r, "Failed to read default route setting for the interface, proceeding anyway: %m");
}
int link_update(Link *l) {
int r;
assert(l);
link_read_settings(l);
r = link_load_user(l);
if (r < 0)
return r;
if (link_get_llmnr_support(l) != RESOLVE_SUPPORT_NO) {
r = manager_llmnr_start(l->manager);
if (r < 0)
return r;
}
if (link_get_mdns_support(l) != RESOLVE_SUPPORT_NO) {
r = manager_mdns_start(l->manager);
if (r < 0)
return r;
}
link_allocate_scopes(l);
link_add_rrs(l, false);
return 0;
}
bool link_relevant(Link *l, int family, bool local_multicast) {
assert(l);
/* A link is relevant for local multicast traffic if it isn't a loopback device, has a link
* beat, can do multicast and has at least one link-local (or better) IP address.
*
* A link is relevant for non-multicast traffic if it isn't a loopback device, has a link beat, and has at
* least one routable address. */
if ((l->flags & (IFF_LOOPBACK | IFF_DORMANT)) != 0)
return false;
if (!FLAGS_SET(l->flags, IFF_UP | IFF_LOWER_UP))
return false;
if (local_multicast &&
!FLAGS_SET(l->flags, IFF_MULTICAST))
return false;
if (!netif_has_carrier(l->operstate, l->flags))
return false;
if (l->is_managed &&
!IN_SET(l->networkd_operstate, LINK_OPERSTATE_DEGRADED_CARRIER, LINK_OPERSTATE_DEGRADED, LINK_OPERSTATE_ROUTABLE))
return false;
LIST_FOREACH(addresses, a, l->addresses)
if ((family == AF_UNSPEC || a->family == family) && link_address_relevant(a, local_multicast))
return true;
return false;
}
LinkAddress *link_find_address(Link *l, int family, const union in_addr_union *in_addr) {
assert(l);
if (!IN_SET(family, AF_INET, AF_INET6))
return NULL;
if (!in_addr)
return NULL;
LIST_FOREACH(addresses, a, l->addresses)
if (a->family == family && in_addr_equal(family, &a->in_addr, in_addr))
return a;
return NULL;
}
DnsServer* link_set_dns_server(Link *l, DnsServer *s) {
assert(l);
if (l->current_dns_server == s)
return s;
if (s)
log_link_debug(l, "Switching to DNS server %s.", strna(dns_server_string_full(s)));
dns_server_unref(l->current_dns_server);
l->current_dns_server = dns_server_ref(s);
/* Skip flushing the cache if server stale feature is enabled. */
if (l->unicast_scope && l->manager->stale_retention_usec == 0)
dns_cache_flush(&l->unicast_scope->cache);
return s;
}
DnsServer *link_get_dns_server(Link *l) {
assert(l);
if (!l->current_dns_server)
link_set_dns_server(l, l->dns_servers);
return l->current_dns_server;
}
void link_next_dns_server(Link *l, DnsServer *if_current) {
assert(l);
/* If the current server of the transaction is specified, and we already are at a different one,
* don't do anything */
if (if_current && l->current_dns_server != if_current)
return;
/* If currently have no DNS server, then don't do anything, we'll pick it lazily the next time a DNS
* server is needed. */
if (!l->current_dns_server)
return;
/* Change to the next one, but make sure to follow the linked list only if this server is actually
* still linked. */
if (l->current_dns_server->linked && l->current_dns_server->servers_next) {
link_set_dns_server(l, l->current_dns_server->servers_next);
return;
}
/* Pick the first one again, after we reached the end */
link_set_dns_server(l, l->dns_servers);
}
DnsOverTlsMode link_get_dns_over_tls_mode(Link *l) {
assert(l);
if (l->dns_over_tls_mode != _DNS_OVER_TLS_MODE_INVALID)
return l->dns_over_tls_mode;
return manager_get_dns_over_tls_mode(l->manager);
}
DnssecMode link_get_dnssec_mode(Link *l) {
assert(l);
if (l->dnssec_mode != _DNSSEC_MODE_INVALID)
return l->dnssec_mode;
return manager_get_dnssec_mode(l->manager);
}
bool link_dnssec_supported(Link *l) {
DnsServer *server;
assert(l);
if (link_get_dnssec_mode(l) == DNSSEC_NO)
return false;
server = link_get_dns_server(l);
if (server)
return dns_server_dnssec_supported(server);
return true;
}
ResolveSupport link_get_llmnr_support(Link *link) {
assert(link);
assert(link->manager);
/* This provides the effective LLMNR support level for the link, instead of the 'internal' per-link setting. */
return MIN(link->llmnr_support, link->manager->llmnr_support);
}
ResolveSupport link_get_mdns_support(Link *link) {
assert(link);
assert(link->manager);
/* This provides the effective mDNS support level for the link, instead of the 'internal' per-link setting. */
return MIN(link->mdns_support, link->manager->mdns_support);
}
int link_address_new(Link *l,
LinkAddress **ret,
int family,
const union in_addr_union *in_addr,
const union in_addr_union *in_addr_broadcast) {
LinkAddress *a;
assert(l);
assert(in_addr);
a = new(LinkAddress, 1);
if (!a)
return -ENOMEM;
*a = (LinkAddress) {
.family = family,
.in_addr = *in_addr,
.in_addr_broadcast = *in_addr_broadcast,
.link = l,
.prefixlen = UCHAR_MAX,
};
LIST_PREPEND(addresses, l->addresses, a);
l->n_addresses++;
if (ret)
*ret = a;
return 0;
}
LinkAddress *link_address_free(LinkAddress *a) {
if (!a)
return NULL;
if (a->link) {
LIST_REMOVE(addresses, a->link->addresses, a);
assert(a->link->n_addresses > 0);
a->link->n_addresses--;
if (a->llmnr_address_rr) {
if (a->family == AF_INET && a->link->llmnr_ipv4_scope)
dns_zone_remove_rr(&a->link->llmnr_ipv4_scope->zone, a->llmnr_address_rr);
else if (a->family == AF_INET6 && a->link->llmnr_ipv6_scope)
dns_zone_remove_rr(&a->link->llmnr_ipv6_scope->zone, a->llmnr_address_rr);
}
if (a->llmnr_ptr_rr) {
if (a->family == AF_INET && a->link->llmnr_ipv4_scope)
dns_zone_remove_rr(&a->link->llmnr_ipv4_scope->zone, a->llmnr_ptr_rr);
else if (a->family == AF_INET6 && a->link->llmnr_ipv6_scope)
dns_zone_remove_rr(&a->link->llmnr_ipv6_scope->zone, a->llmnr_ptr_rr);
}
if (a->mdns_address_rr) {
if (a->family == AF_INET && a->link->mdns_ipv4_scope)
dns_zone_remove_rr(&a->link->mdns_ipv4_scope->zone, a->mdns_address_rr);
else if (a->family == AF_INET6 && a->link->mdns_ipv6_scope)
dns_zone_remove_rr(&a->link->mdns_ipv6_scope->zone, a->mdns_address_rr);
}
if (a->mdns_ptr_rr) {
if (a->family == AF_INET && a->link->mdns_ipv4_scope)
dns_zone_remove_rr(&a->link->mdns_ipv4_scope->zone, a->mdns_ptr_rr);
else if (a->family == AF_INET6 && a->link->mdns_ipv6_scope)
dns_zone_remove_rr(&a->link->mdns_ipv6_scope->zone, a->mdns_ptr_rr);
}
}
dns_resource_record_unref(a->llmnr_address_rr);
dns_resource_record_unref(a->llmnr_ptr_rr);
dns_resource_record_unref(a->mdns_address_rr);
dns_resource_record_unref(a->mdns_ptr_rr);
return mfree(a);
}
void link_address_add_rrs(LinkAddress *a, bool force_remove) {
int r;
assert(a);
if (a->family == AF_INET) {
if (!force_remove &&
link_address_relevant(a, true) &&
a->link->llmnr_ipv4_scope &&
link_get_llmnr_support(a->link) == RESOLVE_SUPPORT_YES) {
if (!a->link->manager->llmnr_host_ipv4_key) {
a->link->manager->llmnr_host_ipv4_key = dns_resource_key_new(DNS_CLASS_IN, DNS_TYPE_A, a->link->manager->llmnr_hostname);
if (!a->link->manager->llmnr_host_ipv4_key) {
r = -ENOMEM;
goto fail;
}
}
if (!a->llmnr_address_rr) {
a->llmnr_address_rr = dns_resource_record_new(a->link->manager->llmnr_host_ipv4_key);
if (!a->llmnr_address_rr) {
r = -ENOMEM;
goto fail;
}
a->llmnr_address_rr->a.in_addr = a->in_addr.in;
a->llmnr_address_rr->ttl = LLMNR_DEFAULT_TTL;
}
if (!a->llmnr_ptr_rr) {
r = dns_resource_record_new_reverse(&a->llmnr_ptr_rr, a->family, &a->in_addr, a->link->manager->llmnr_hostname);
if (r < 0)
goto fail;
a->llmnr_ptr_rr->ttl = LLMNR_DEFAULT_TTL;
}
r = dns_zone_put(&a->link->llmnr_ipv4_scope->zone, a->link->llmnr_ipv4_scope, a->llmnr_address_rr, true);
if (r < 0)
log_link_warning_errno(a->link, r, "Failed to add A record to LLMNR zone, ignoring: %m");
r = dns_zone_put(&a->link->llmnr_ipv4_scope->zone, a->link->llmnr_ipv4_scope, a->llmnr_ptr_rr, false);
if (r < 0)
log_link_warning_errno(a->link, r, "Failed to add IPv4 PTR record to LLMNR zone, ignoring: %m");
} else {
if (a->llmnr_address_rr) {
if (a->link->llmnr_ipv4_scope)
dns_zone_remove_rr(&a->link->llmnr_ipv4_scope->zone, a->llmnr_address_rr);
a->llmnr_address_rr = dns_resource_record_unref(a->llmnr_address_rr);
}
if (a->llmnr_ptr_rr) {
if (a->link->llmnr_ipv4_scope)
dns_zone_remove_rr(&a->link->llmnr_ipv4_scope->zone, a->llmnr_ptr_rr);
a->llmnr_ptr_rr = dns_resource_record_unref(a->llmnr_ptr_rr);
}
}
if (!force_remove &&
link_address_relevant(a, true) &&
a->link->mdns_ipv4_scope &&
link_get_mdns_support(a->link) == RESOLVE_SUPPORT_YES) {
if (!a->link->manager->mdns_host_ipv4_key) {
a->link->manager->mdns_host_ipv4_key = dns_resource_key_new(DNS_CLASS_IN, DNS_TYPE_A, a->link->manager->mdns_hostname);
if (!a->link->manager->mdns_host_ipv4_key) {
r = -ENOMEM;
goto fail;
}
}
if (!a->mdns_address_rr) {
a->mdns_address_rr = dns_resource_record_new(a->link->manager->mdns_host_ipv4_key);
if (!a->mdns_address_rr) {
r = -ENOMEM;
goto fail;
}
a->mdns_address_rr->a.in_addr = a->in_addr.in;
a->mdns_address_rr->ttl = MDNS_DEFAULT_TTL;
}
if (!a->mdns_ptr_rr) {
r = dns_resource_record_new_reverse(&a->mdns_ptr_rr, a->family, &a->in_addr, a->link->manager->mdns_hostname);
if (r < 0)
goto fail;
a->mdns_ptr_rr->ttl = MDNS_DEFAULT_TTL;
}
r = dns_zone_put(&a->link->mdns_ipv4_scope->zone, a->link->mdns_ipv4_scope, a->mdns_address_rr, true);
if (r < 0)
log_link_warning_errno(a->link, r, "Failed to add A record to MDNS zone, ignoring: %m");
r = dns_zone_put(&a->link->mdns_ipv4_scope->zone, a->link->mdns_ipv4_scope, a->mdns_ptr_rr, false);
if (r < 0)
log_link_warning_errno(a->link, r, "Failed to add IPv4 PTR record to MDNS zone, ignoring: %m");
} else {
if (a->mdns_address_rr) {
if (a->link->mdns_ipv4_scope)
dns_zone_remove_rr(&a->link->mdns_ipv4_scope->zone, a->mdns_address_rr);
a->mdns_address_rr = dns_resource_record_unref(a->mdns_address_rr);
}
if (a->mdns_ptr_rr) {
if (a->link->mdns_ipv4_scope)
dns_zone_remove_rr(&a->link->mdns_ipv4_scope->zone, a->mdns_ptr_rr);
a->mdns_ptr_rr = dns_resource_record_unref(a->mdns_ptr_rr);
}
}
}
if (a->family == AF_INET6) {
if (!force_remove &&
link_address_relevant(a, true) &&
a->link->llmnr_ipv6_scope &&
link_get_llmnr_support(a->link) == RESOLVE_SUPPORT_YES) {
if (!a->link->manager->llmnr_host_ipv6_key) {
a->link->manager->llmnr_host_ipv6_key = dns_resource_key_new(DNS_CLASS_IN, DNS_TYPE_AAAA, a->link->manager->llmnr_hostname);
if (!a->link->manager->llmnr_host_ipv6_key) {
r = -ENOMEM;
goto fail;
}
}
if (!a->llmnr_address_rr) {
a->llmnr_address_rr = dns_resource_record_new(a->link->manager->llmnr_host_ipv6_key);
if (!a->llmnr_address_rr) {
r = -ENOMEM;
goto fail;
}
a->llmnr_address_rr->aaaa.in6_addr = a->in_addr.in6;
a->llmnr_address_rr->ttl = LLMNR_DEFAULT_TTL;
}
if (!a->llmnr_ptr_rr) {
r = dns_resource_record_new_reverse(&a->llmnr_ptr_rr, a->family, &a->in_addr, a->link->manager->llmnr_hostname);
if (r < 0)
goto fail;
a->llmnr_ptr_rr->ttl = LLMNR_DEFAULT_TTL;
}
r = dns_zone_put(&a->link->llmnr_ipv6_scope->zone, a->link->llmnr_ipv6_scope, a->llmnr_address_rr, true);
if (r < 0)
log_link_warning_errno(a->link, r, "Failed to add AAAA record to LLMNR zone, ignoring: %m");
r = dns_zone_put(&a->link->llmnr_ipv6_scope->zone, a->link->llmnr_ipv6_scope, a->llmnr_ptr_rr, false);
if (r < 0)
log_link_warning_errno(a->link, r, "Failed to add IPv6 PTR record to LLMNR zone, ignoring: %m");
} else {
if (a->llmnr_address_rr) {
if (a->link->llmnr_ipv6_scope)
dns_zone_remove_rr(&a->link->llmnr_ipv6_scope->zone, a->llmnr_address_rr);
a->llmnr_address_rr = dns_resource_record_unref(a->llmnr_address_rr);
}
if (a->llmnr_ptr_rr) {
if (a->link->llmnr_ipv6_scope)
dns_zone_remove_rr(&a->link->llmnr_ipv6_scope->zone, a->llmnr_ptr_rr);
a->llmnr_ptr_rr = dns_resource_record_unref(a->llmnr_ptr_rr);
}
}
if (!force_remove &&
link_address_relevant(a, true) &&
a->link->mdns_ipv6_scope &&
link_get_mdns_support(a->link) == RESOLVE_SUPPORT_YES) {
if (!a->link->manager->mdns_host_ipv6_key) {
a->link->manager->mdns_host_ipv6_key = dns_resource_key_new(DNS_CLASS_IN, DNS_TYPE_AAAA, a->link->manager->mdns_hostname);
if (!a->link->manager->mdns_host_ipv6_key) {
r = -ENOMEM;
goto fail;
}
}
if (!a->mdns_address_rr) {
a->mdns_address_rr = dns_resource_record_new(a->link->manager->mdns_host_ipv6_key);
if (!a->mdns_address_rr) {
r = -ENOMEM;
goto fail;
}
a->mdns_address_rr->aaaa.in6_addr = a->in_addr.in6;
a->mdns_address_rr->ttl = MDNS_DEFAULT_TTL;
}
if (!a->mdns_ptr_rr) {
r = dns_resource_record_new_reverse(&a->mdns_ptr_rr, a->family, &a->in_addr, a->link->manager->mdns_hostname);
if (r < 0)
goto fail;
a->mdns_ptr_rr->ttl = MDNS_DEFAULT_TTL;
}
r = dns_zone_put(&a->link->mdns_ipv6_scope->zone, a->link->mdns_ipv6_scope, a->mdns_address_rr, true);
if (r < 0)
log_link_warning_errno(a->link, r, "Failed to add AAAA record to MDNS zone, ignoring: %m");
r = dns_zone_put(&a->link->mdns_ipv6_scope->zone, a->link->mdns_ipv6_scope, a->mdns_ptr_rr, false);
if (r < 0)
log_link_warning_errno(a->link, r, "Failed to add IPv6 PTR record to MDNS zone, ignoring: %m");
} else {
if (a->mdns_address_rr) {
if (a->link->mdns_ipv6_scope)
dns_zone_remove_rr(&a->link->mdns_ipv6_scope->zone, a->mdns_address_rr);
a->mdns_address_rr = dns_resource_record_unref(a->mdns_address_rr);
}
if (a->mdns_ptr_rr) {
if (a->link->mdns_ipv6_scope)
dns_zone_remove_rr(&a->link->mdns_ipv6_scope->zone, a->mdns_ptr_rr);
a->mdns_ptr_rr = dns_resource_record_unref(a->mdns_ptr_rr);
}
}
}
return;
fail:
log_link_debug_errno(a->link, r, "Failed to update address RRs, ignoring: %m");
}
int link_address_update_rtnl(LinkAddress *a, sd_netlink_message *m) {
int r;
assert(a);
assert(m);
r = sd_rtnl_message_addr_get_flags(m, &a->flags);
if (r < 0)
return r;
(void) sd_rtnl_message_addr_get_prefixlen(m, &a->prefixlen);
(void) sd_rtnl_message_addr_get_scope(m, &a->scope);
link_allocate_scopes(a->link);
link_add_rrs(a->link, false);
return 0;
}
bool link_address_relevant(LinkAddress *a, bool local_multicast) {
assert(a);
if (a->flags & (IFA_F_DEPRECATED|IFA_F_TENTATIVE))
return false;
if (a->scope >= (local_multicast ? RT_SCOPE_HOST : RT_SCOPE_LINK))
return false;
return true;
}
static bool link_needs_save(Link *l) {
assert(l);
/* Returns true if any of the settings where set different from the default */
if (l->is_managed)
return false;
if (l->llmnr_support != RESOLVE_SUPPORT_YES ||
l->mdns_support != RESOLVE_SUPPORT_YES ||
l->dnssec_mode != _DNSSEC_MODE_INVALID ||
l->dns_over_tls_mode != _DNS_OVER_TLS_MODE_INVALID)
return true;
if (l->dns_servers ||
l->search_domains)
return true;
if (!set_isempty(l->dnssec_negative_trust_anchors))
return true;
if (l->default_route >= 0)
return true;
return false;
}
int link_save_user(Link *l) {
_cleanup_(unlink_and_freep) char *temp_path = NULL;
_cleanup_fclose_ FILE *f = NULL;
const char *v;
int r;
assert(l);
assert(l->state_file);
if (!link_needs_save(l)) {
(void) unlink(l->state_file);
return 0;
}
r = mkdir_parents(l->state_file, 0700);
if (r < 0)
goto fail;
r = fopen_temporary(l->state_file, &f, &temp_path);
if (r < 0)
goto fail;
(void) fchmod(fileno(f), 0644);
fputs("# This is private data. Do not parse.\n", f);
v = resolve_support_to_string(l->llmnr_support);
if (v)
fprintf(f, "LLMNR=%s\n", v);
v = resolve_support_to_string(l->mdns_support);
if (v)
fprintf(f, "MDNS=%s\n", v);
v = dnssec_mode_to_string(l->dnssec_mode);
if (v)
fprintf(f, "DNSSEC=%s\n", v);
v = dns_over_tls_mode_to_string(l->dns_over_tls_mode);
if (v)
fprintf(f, "DNSOVERTLS=%s\n", v);
if (l->default_route >= 0)
fprintf(f, "DEFAULT_ROUTE=%s\n", yes_no(l->default_route));
if (l->dns_servers) {
fputs("SERVERS=", f);
LIST_FOREACH(servers, server, l->dns_servers) {
if (server != l->dns_servers)
fputc(' ', f);
v = dns_server_string_full(server);
if (!v) {
r = -ENOMEM;
goto fail;
}
fputs(v, f);
}
fputc('\n', f);
}
if (l->search_domains) {
fputs("DOMAINS=", f);
LIST_FOREACH(domains, domain, l->search_domains) {
if (domain != l->search_domains)
fputc(' ', f);
if (domain->route_only)
fputc('~', f);
fputs(DNS_SEARCH_DOMAIN_NAME(domain), f);
}
fputc('\n', f);
}
if (!set_isempty(l->dnssec_negative_trust_anchors)) {
bool space = false;
char *nta;
fputs("NTAS=", f);
SET_FOREACH(nta, l->dnssec_negative_trust_anchors) {
if (space)
fputc(' ', f);
fputs(nta, f);
space = true;
}
fputc('\n', f);
}
r = fflush_and_check(f);
if (r < 0)
goto fail;
if (rename(temp_path, l->state_file) < 0) {
r = -errno;
goto fail;
}
temp_path = mfree(temp_path);
return 0;
fail:
(void) unlink(l->state_file);
return log_link_error_errno(l, r, "Failed to save link data %s: %m", l->state_file);
}
int link_load_user(Link *l) {
_cleanup_free_ char
*llmnr = NULL,
*mdns = NULL,
*dnssec = NULL,
*dns_over_tls = NULL,
*servers = NULL,
*domains = NULL,
*ntas = NULL,
*default_route = NULL;
ResolveSupport s;
const char *p;
int r;
assert(l);
assert(l->state_file);
/* Try to load only a single time */
if (l->loaded)
return 0;
l->loaded = true;
if (l->is_managed)
return 0; /* if the device is managed, then networkd is our configuration source, not the bus API */
r = parse_env_file(NULL, l->state_file,
"LLMNR", &llmnr,
"MDNS", &mdns,
"DNSSEC", &dnssec,
"DNSOVERTLS", &dns_over_tls,
"SERVERS", &servers,
"DOMAINS", &domains,
"NTAS", &ntas,
"DEFAULT_ROUTE", &default_route);
if (r == -ENOENT)
return 0;
if (r < 0)
goto fail;
link_flush_settings(l);
/* If we can't recognize the LLMNR or MDNS setting we don't override the default */
s = resolve_support_from_string(llmnr);
if (s >= 0)
l->llmnr_support = s;
s = resolve_support_from_string(mdns);
if (s >= 0)
l->mdns_support = s;
r = parse_boolean(default_route);
if (r >= 0)
l->default_route = r;
/* If we can't recognize the DNSSEC setting, then set it to invalid, so that the daemon default is used. */
l->dnssec_mode = dnssec_mode_from_string(dnssec);
/* Same for DNSOverTLS */
l->dns_over_tls_mode = dns_over_tls_mode_from_string(dns_over_tls);
for (p = servers;;) {
_cleanup_free_ char *word = NULL;
r = extract_first_word(&p, &word, NULL, 0);
if (r < 0)
goto fail;
if (r == 0)
break;
r = link_update_dns_server_one(l, word);
if (r < 0) {
log_link_debug_errno(l, r, "Failed to load DNS server '%s', ignoring: %m", word);
continue;
}
}
for (p = domains;;) {
_cleanup_free_ char *word = NULL;
const char *n;
bool is_route;
r = extract_first_word(&p, &word, NULL, 0);
if (r < 0)
goto fail;
if (r == 0)
break;
is_route = word[0] == '~';
n = is_route ? word + 1 : word;
r = link_update_search_domain_one(l, n, is_route);
if (r < 0) {
log_link_debug_errno(l, r, "Failed to load search domain '%s', ignoring: %m", word);
continue;
}
}
if (ntas) {
_cleanup_set_free_free_ Set *ns = NULL;
ns = set_new(&dns_name_hash_ops);
if (!ns) {
r = -ENOMEM;
goto fail;
}
r = set_put_strsplit(ns, ntas, NULL, 0);
if (r < 0)
goto fail;
l->dnssec_negative_trust_anchors = TAKE_PTR(ns);
}
return 0;
fail:
return log_link_error_errno(l, r, "Failed to load link data %s: %m", l->state_file);
}
void link_remove_user(Link *l) {
assert(l);
assert(l->state_file);
(void) unlink(l->state_file);
}
bool link_negative_trust_anchor_lookup(Link *l, const char *name) {
int r;
assert(l);
assert(name);
/* Checks whether the specified domain (or any of its parent domains) are listed as per-link NTA. */
for (;;) {
if (set_contains(l->dnssec_negative_trust_anchors, name))
return true;
/* And now, let's look at the parent, and check that too */
r = dns_name_parent(&name);
if (r < 0)
return r;
if (r == 0)
break;
}
return false;
}
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