resolved: add bus API for configuring per-link DNS settings

This is useful for alternative network management solutions (such as NetworkManager) to push DNS configuration data
into resolved.

The calls will fail should networkd already have taken possesion of a link, so that the bus API is only available if
we don't get the data from networkd.

1 files changed, 355 insertions, 0 deletions

diff --git a/src/resolve/resolved-bus.c b/src/resolve/resolved-bus.c
index db7b88e5fb..d596472527 100644
--- a/src/resolve/resolved-bus.c
+++ b/src/resolve/resolved-bus.c
@@ -1339,6 +1339,353 @@ static int bus_method_reset_statistics(sd_bus_message *message, void *userdata,
         return sd_bus_reply_method_return(message, NULL);
 }
 
+static int get_unmanaged_link(Manager *m, int ifindex, Link **ret, sd_bus_error *error) {
+        Link *l;
+
+        assert(m);
+
+        if (ifindex <= 0)
+                return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid interface index");
+
+        l = hashmap_get(m->links, INT_TO_PTR(ifindex));
+        if (!l)
+                return sd_bus_error_setf(error, BUS_ERROR_NO_SUCH_LINK, "Link %i not known", ifindex);
+        if (l->flags & IFF_LOOPBACK)
+                return sd_bus_error_setf(error, BUS_ERROR_LINK_BUSY, "Link %s is loopback device.", l->name);
+        if (l->is_managed)
+                return sd_bus_error_setf(error, BUS_ERROR_LINK_BUSY, "Link %s is managed.", l->name);
+
+        *ret = l;
+        return 0;
+}
+
+static int bus_method_set_link_dns_servers(sd_bus_message *message, void *userdata, sd_bus_error *error) {
+        _cleanup_free_ struct in_addr_data *dns = NULL;
+        size_t allocated = 0, n = 0;
+        Manager *m = userdata;
+        int ifindex, r;
+        unsigned i;
+        Link *l;
+
+        assert(message);
+        assert(m);
+
+        r = sd_bus_message_read(message, "i", &ifindex);
+        if (r < 0)
+                return r;
+
+        r = get_unmanaged_link(m, ifindex, &l, error);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_enter_container(message, 'a', "(iay)");
+        if (r < 0)
+                return r;
+
+        for (;;) {
+                int family;
+                size_t sz;
+                const void *d;
+
+                assert_cc(sizeof(int) == sizeof(int32_t));
+
+                r = sd_bus_message_enter_container(message, 'r', "iay");
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        break;
+
+                r = sd_bus_message_read(message, "i", &family);
+                if (r < 0)
+                        return r;
+
+                if (!IN_SET(family, AF_INET, AF_INET6))
+                        return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Unknown address family %i", family);
+
+                r = sd_bus_message_read_array(message, 'y', &d, &sz);
+                if (r < 0)
+                        return r;
+                if (sz != FAMILY_ADDRESS_SIZE(family))
+                        return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid address size");
+
+                r = sd_bus_message_exit_container(message);
+                if (r < 0)
+                        return r;
+
+                if (!GREEDY_REALLOC(dns, allocated, n+1))
+                        return -ENOMEM;
+
+                dns[n].family = family;
+                memcpy(&dns[n].address, d, sz);
+                n++;
+        }
+
+        r = sd_bus_message_exit_container(message);
+        if (r < 0)
+                return r;
+
+        dns_server_mark_all(l->dns_servers);
+
+        for (i = 0; i < n; i++) {
+                DnsServer *s;
+
+                s = dns_server_find(l->dns_servers, dns[i].family, &dns[i].address);
+                if (s)
+                        dns_server_move_back_and_unmark(s);
+                else {
+                        r = dns_server_new(l->manager, NULL, DNS_SERVER_LINK, l, dns[i].family, &dns[i].address);
+                        if (r < 0)
+                                goto clear;
+                }
+
+        }
+
+        dns_server_unlink_marked(l->dns_servers);
+        link_allocate_scopes(l);
+
+        return sd_bus_reply_method_return(message, NULL);
+
+clear:
+        dns_server_unlink_all(l->dns_servers);
+        return r;
+}
+
+static int bus_method_set_link_domains(sd_bus_message *message, void *userdata, sd_bus_error *error) {
+        _cleanup_free_ char **domains = NULL;
+        Manager *m = userdata;
+        int ifindex, r;
+        char **i;
+        Link *l;
+
+        assert(message);
+        assert(m);
+
+        r = sd_bus_message_read(message, "i", &ifindex);
+        if (r < 0)
+                return r;
+
+        r = get_unmanaged_link(m, ifindex, &l, error);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_read_strv(message, &domains);
+        if (r < 0)
+                return r;
+
+        STRV_FOREACH(i, domains) {
+
+                r = dns_name_is_valid(*i);
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid search domain %s", *i);
+                if (dns_name_is_root(*i))
+                        return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Root domain is not suitable as search domain");
+        }
+
+        dns_search_domain_mark_all(l->search_domains);
+
+        STRV_FOREACH(i, domains) {
+                DnsSearchDomain *d;
+
+                r = dns_search_domain_find(l->search_domains, *i, &d);
+                if (r < 0)
+                        goto clear;
+
+                if (r > 0)
+                        dns_search_domain_move_back_and_unmark(d);
+                else {
+                        r = dns_search_domain_new(l->manager, NULL, DNS_SEARCH_DOMAIN_LINK, l, *i);
+                        if (r < 0)
+                                goto clear;
+                }
+        }
+
+        dns_search_domain_unlink_marked(l->search_domains);
+        return sd_bus_reply_method_return(message, NULL);
+
+clear:
+        dns_search_domain_unlink_all(l->search_domains);
+        return r;
+}
+
+static int bus_method_set_link_llmnr(sd_bus_message *message, void *userdata, sd_bus_error *error) {
+        Manager *m = userdata;
+        ResolveSupport mode;
+        const char *llmnr;
+        int ifindex, r;
+        Link *l;
+
+        assert(message);
+        assert(m);
+
+        assert_cc(sizeof(int) == sizeof(int32_t));
+
+        r = sd_bus_message_read(message, "is", &ifindex, &llmnr);
+        if (r < 0)
+                return r;
+
+        if (isempty(llmnr))
+                mode = RESOLVE_SUPPORT_YES;
+        else {
+                mode = resolve_support_from_string(llmnr);
+                if (mode < 0)
+                        return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid LLMNR setting: %s", llmnr);
+        }
+
+        r = get_unmanaged_link(m, ifindex, &l, error);
+        if (r < 0)
+                return r;
+
+        l->llmnr_support = mode;
+        link_allocate_scopes(l);
+        link_add_rrs(l, false);
+
+        return sd_bus_reply_method_return(message, NULL);
+}
+
+static int bus_method_set_link_mdns(sd_bus_message *message, void *userdata, sd_bus_error *error) {
+        Manager *m = userdata;
+        ResolveSupport mode;
+        const char *mdns;
+        int ifindex, r;
+        Link *l;
+
+        assert(message);
+        assert(m);
+
+        assert_cc(sizeof(int) == sizeof(int32_t));
+
+        r = sd_bus_message_read(message, "is", &ifindex, &mdns);
+        if (r < 0)
+                return r;
+
+        if (isempty(mdns))
+                mode = RESOLVE_SUPPORT_NO;
+        else {
+                mode = resolve_support_from_string(mdns);
+                if (mode < 0)
+                        return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid MulticastDNS setting: %s", mdns);
+        }
+
+        r = get_unmanaged_link(m, ifindex, &l, error);
+        if (r < 0)
+                return r;
+
+        l->mdns_support = mode;
+        link_allocate_scopes(l);
+        link_add_rrs(l, false);
+
+        return sd_bus_reply_method_return(message, NULL);
+}
+
+static int bus_method_set_link_dnssec(sd_bus_message *message, void *userdata, sd_bus_error *error) {
+        Manager *m = userdata;
+        const char *dnssec;
+        DnssecMode mode;
+        int ifindex, r;
+        Link *l;
+
+        assert(message);
+        assert(m);
+
+        assert_cc(sizeof(int) == sizeof(int32_t));
+
+        r = sd_bus_message_read(message, "is", &ifindex, &dnssec);
+        if (r < 0)
+                return r;
+
+        if (isempty(dnssec))
+                mode = _DNSSEC_MODE_INVALID;
+        else {
+                mode = dnssec_mode_from_string(dnssec);
+                if (mode < 0)
+                        return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid DNSSEC setting: %s", dnssec);
+        }
+
+        r = get_unmanaged_link(m, ifindex, &l, error);
+        if (r < 0)
+                return r;
+
+        link_set_dnssec_mode(l, mode);
+
+        return sd_bus_reply_method_return(message, NULL);
+}
+
+static int bus_method_set_link_dnssec_negative_trust_anchors(sd_bus_message *message, void *userdata, sd_bus_error *error) {
+        _cleanup_set_free_free_ Set *ns = NULL;
+        _cleanup_free_ char **ntas = NULL;
+        Manager *m = userdata;
+        int ifindex, r;
+        char **i;
+        Link *l;
+
+        assert(message);
+        assert(m);
+
+        r = sd_bus_message_read(message, "i", &ifindex);
+        if (r < 0)
+                return r;
+
+        r = get_unmanaged_link(m, ifindex, &l, error);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_message_read_strv(message, &ntas);
+        if (r < 0)
+                return r;
+
+        STRV_FOREACH(i, ntas) {
+                r = dns_name_is_valid(*i);
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        return sd_bus_error_setf(error, SD_BUS_ERROR_INVALID_ARGS, "Invalid search negative trust anchor domain: %s", *i);
+        }
+
+        ns = set_new(&dns_name_hash_ops);
+        if (!ns)
+                return -ENOMEM;
+
+        STRV_FOREACH(i, ntas) {
+                r = set_put_strdup(ns, *i);
+                if (r < 0)
+                        return r;
+        }
+
+        set_free_free(l->dnssec_negative_trust_anchors);
+        l->dnssec_negative_trust_anchors = ns;
+        ns = NULL;
+
+        return sd_bus_reply_method_return(message, NULL);
+}
+
+static int bus_method_revert_link(sd_bus_message *message, void *userdata, sd_bus_error *error) {
+        Manager *m = userdata;
+        int ifindex;
+        Link *l;
+        int r;
+
+        assert(message);
+        assert(m);
+
+        assert_cc(sizeof(int) == sizeof(int32_t));
+
+        r = sd_bus_message_read(message, "i", &ifindex);
+        if (r < 0)
+                return r;
+
+        r = get_unmanaged_link(m, ifindex, &l, error);
+        if (r < 0)
+                return r;
+
+        link_flush_settings(l);
+        link_allocate_scopes(l);
+        link_add_rrs(l, false);
+
+        return sd_bus_reply_method_return(message, NULL);
+}
+
 static const sd_bus_vtable resolve_vtable[] = {
         SD_BUS_VTABLE_START(0),
         SD_BUS_PROPERTY("LLMNRHostname", "s", NULL, offsetof(Manager, llmnr_hostname), 0),
@@ -1354,6 +1701,14 @@ static const sd_bus_vtable resolve_vtable[] = {
         SD_BUS_METHOD("ResolveRecord", "isqqt", "a(iqqay)t", bus_method_resolve_record, SD_BUS_VTABLE_UNPRIVILEGED),
         SD_BUS_METHOD("ResolveService", "isssit", "a(qqqsa(iiay)s)aayssst", bus_method_resolve_service, SD_BUS_VTABLE_UNPRIVILEGED),
         SD_BUS_METHOD("ResetStatistics", NULL, NULL, bus_method_reset_statistics, 0),
+        SD_BUS_METHOD("SetLinkDNS", "ia(iay)", NULL, bus_method_set_link_dns_servers, 0),
+        SD_BUS_METHOD("SetLinkDomains", "ias", NULL, bus_method_set_link_domains, 0),
+        SD_BUS_METHOD("SetLinkLLMNR", "is", NULL, bus_method_set_link_llmnr, 0),
+        SD_BUS_METHOD("SetLinkMulticastDNS", "is", NULL, bus_method_set_link_mdns, 0),
+        SD_BUS_METHOD("SetLinkDNSSEC", "is", NULL, bus_method_set_link_dnssec, 0),
+        SD_BUS_METHOD("SetLinkDNSSECNegativeTrustAnchors", "ias", NULL, bus_method_set_link_dnssec_negative_trust_anchors, 0),
+        SD_BUS_METHOD("RevertLink", "i", NULL, bus_method_revert_link, 0),
+
         SD_BUS_VTABLE_END,
 };