Merge pull request #6948 from pfl/radv_emit_dns

Add EmitDNS= and EmitDomains= network file configuration options

8 files changed, 167 insertions, 27 deletions

diff --git a/man/systemd.network.xml b/man/systemd.network.xml
index b1759677f9..2fb5886b79 100644
--- a/man/systemd.network.xml
+++ b/man/systemd.network.xml
@@ -1452,19 +1452,36 @@
       </varlistentry>
 
       <varlistentry>
+        <term><varname>EmitDNS=</varname></term>
         <term><varname>DNS=</varname></term>
 
-        <listitem><para>A list of recursive DNS server IPv6 addresses
-        distributed via Router Advertisement messages.
+        <listitem><para><varname>DNS=</varname> specifies a list of recursive
+        DNS server IPv6 addresses that distributed via Router Advertisement
+        messages when <varname>EmitDNS=</varname> is true. If <varname>DNS=
+        </varname> is empty, DNS servers are read from the
+        <literal>[Network]</literal> section. If the
+        <literal>[Network]</literal> section does not contain any DNS servers
+        either, DNS servers from the uplink with the highest priority default
+        route are used. When <varname>EmitDNS=</varname> is false, no DNS server
+        information is sent in Router Advertisement messages.
+        <varname>EmitDNS=</varname> defaults to true.
         </para></listitem>
       </varlistentry>
 
       <varlistentry>
+        <term><varname>EmitDomains=</varname></term>
         <term><varname>Domains=</varname></term>
 
-        <listitem><para>A list of DNS search domains distributed via
-        Router Advertisement messages. Defaults to empty, i.e. no search
-        domains are sent.</para></listitem>
+        <listitem><para>A list of DNS search domains distributed via Router
+        Advertisement messages when <varname>EmitDomains=</varname> is true. If
+        <varname>Domains=</varname> is empty, DNS search domains are read from the
+        <literal>[Network]</literal> section. If the <literal>[Network]</literal>
+        section does not contain any DNS search domains either, DNS search
+        domains from the uplink with the highest priority default route are
+        used. When <varname>EmitDomains=</varname> is false, no DNS search domain
+        information is sent in Router Advertisement messages.
+        <varname>EmitDomains=</varname> defaults to true.
+        </para></listitem>
       </varlistentry>
 
       <varlistentry>
diff --git a/src/libsystemd-network/radv-internal.h b/src/libsystemd-network/radv-internal.h
index 5601be844d..b4d0becdd1 100644
--- a/src/libsystemd-network/radv-internal.h
+++ b/src/libsystemd-network/radv-internal.h
@@ -25,8 +25,6 @@
 #include "list.h"
 #include "sparse-endian.h"
 
-#define SD_RADV_DEFAULT_MIN_TIMEOUT_USEC        (200*USEC_PER_SEC)
-#define SD_RADV_DEFAULT_MAX_TIMEOUT_USEC        (600*USEC_PER_SEC)
 assert_cc(SD_RADV_DEFAULT_MIN_TIMEOUT_USEC <= SD_RADV_DEFAULT_MAX_TIMEOUT_USEC)
 
 #define SD_RADV_MAX_INITIAL_RTR_ADVERT_INTERVAL_USEC (16*USEC_PER_SEC)
diff --git a/src/network/networkd-network-gperf.gperf b/src/network/networkd-network-gperf.gperf
index af39d77ce9..ca0d67e3d2 100644
--- a/src/network/networkd-network-gperf.gperf
+++ b/src/network/networkd-network-gperf.gperf
@@ -152,7 +152,9 @@ IPv6PrefixDelegation.RouterLifetimeSec, config_parse_sec,
 IPv6PrefixDelegation.Managed,           config_parse_bool,                              0,                             offsetof(Network, router_managed)
 IPv6PrefixDelegation.OtherInformation,  config_parse_bool,                              0,                             offsetof(Network, router_other_information)
 IPv6PrefixDelegation.RouterPreference,  config_parse_router_preference,                 0,                             0
+IPv6PrefixDelegation.EmitDNS,           config_parse_bool,                              0,                             offsetof(Network, router_emit_dns)
 IPv6PrefixDelegation.DNS,               config_parse_radv_dns,                          0,                             0
+IPv6PrefixDelegation.EmitDomains,       config_parse_bool,                              0,                             offsetof(Network, router_emit_domains)
 IPv6PrefixDelegation.Domains,           config_parse_radv_search_domains,               0,                             0
 IPv6PrefixDelegation.DNSLifetimeSec,    config_parse_sec,                               0,                             offsetof(Network, router_dns_lifetime_usec)
 IPv6Prefix.Prefix,                      config_parse_prefix,                            0,                             0
diff --git a/src/network/networkd-network.c b/src/network/networkd-network.c
index 3a7eb2c2a8..bf54a57f3b 100644
--- a/src/network/networkd-network.c
+++ b/src/network/networkd-network.c
@@ -233,6 +233,9 @@ static int network_load_one(Manager *manager, const char *filename) {
         network->dhcp_server_emit_router = true;
         network->dhcp_server_emit_timezone = true;
 
+        network->router_emit_dns = true;
+        network->router_emit_domains = true;
+
         network->use_bpdu = true;
         network->allow_port_to_be_root = true;
         network->unicast_flood = true;
diff --git a/src/network/networkd-network.h b/src/network/networkd-network.h
index 9fb0eae380..500325fbd0 100644
--- a/src/network/networkd-network.h
+++ b/src/network/networkd-network.h
@@ -167,6 +167,8 @@ struct Network {
         uint8_t router_preference;
         bool router_managed;
         bool router_other_information;
+        bool router_emit_dns;
+        bool router_emit_domains;
         usec_t router_dns_lifetime_usec;
         struct in6_addr *router_dns;
         unsigned n_router_dns;
diff --git a/src/network/networkd-radv.c b/src/network/networkd-radv.c
index 6768208cfa..5c807b887a 100644
--- a/src/network/networkd-radv.c
+++ b/src/network/networkd-radv.c
@@ -21,9 +21,140 @@
 #include <arpa/inet.h>
 
 #include "networkd-address.h"
+#include "networkd-manager.h"
 #include "networkd-radv.h"
 #include "sd-radv.h"
 
+static int radv_get_ip6dns(Network *network, struct in6_addr **dns,
+                           size_t *n_dns) {
+        _cleanup_free_ struct in6_addr *addresses = NULL;
+        size_t i, n_addresses = 0, n_allocated = 0;
+
+        assert(network);
+        assert(dns);
+        assert(n_dns);
+
+        for (i = 0; i < network->n_dns; i++) {
+                union in_addr_union *addr;
+
+                if (network->dns[i].family != AF_INET6)
+                        continue;
+
+                addr = &network->dns[i].address;
+
+                if (in_addr_is_null(AF_INET6, addr) ||
+                    in_addr_is_link_local(AF_INET6, addr) ||
+                    in_addr_is_localhost(AF_INET6, addr))
+                        continue;
+
+                if (!GREEDY_REALLOC(addresses, n_allocated, n_addresses + 1))
+                        return -ENOMEM;
+
+                addresses[n_addresses++] = addr->in6;
+        }
+
+        if (addresses) {
+                *dns = addresses;
+                addresses = NULL;
+
+                *n_dns = n_addresses;
+        }
+
+        return n_addresses;
+}
+
+static int radv_set_dns(Link *link, Link *uplink) {
+        _cleanup_free_ struct in6_addr *dns = NULL;
+        size_t n_dns;
+        usec_t lifetime_usec;
+        int r;
+
+        if (!link->network->router_emit_dns)
+                return 0;
+
+        if (link->network->router_dns) {
+                dns = newdup(struct in6_addr, link->network->router_dns,
+                             link->network->n_router_dns);
+                if (dns == NULL)
+                        return -ENOMEM;
+
+                n_dns = link->network->n_router_dns;
+                lifetime_usec = link->network->router_dns_lifetime_usec;
+
+                goto set_dns;
+        }
+
+        lifetime_usec = SD_RADV_DEFAULT_DNS_LIFETIME_USEC;
+
+        r = radv_get_ip6dns(link->network, &dns, &n_dns);
+        if (r > 0)
+                goto set_dns;
+
+        if (uplink) {
+                r = radv_get_ip6dns(uplink->network, &dns, &n_dns);
+                if (r > 0)
+                        goto set_dns;
+        }
+
+        return 0;
+
+ set_dns:
+        return sd_radv_set_rdnss(link->radv,
+                                 DIV_ROUND_UP(lifetime_usec, USEC_PER_SEC),
+                                 dns, n_dns);
+}
+
+static int radv_set_domains(Link *link, Link *uplink) {
+        char **search_domains;
+        usec_t lifetime_usec;
+
+        if (!link->network->router_emit_domains)
+                return 0;
+
+        search_domains = link->network->router_search_domains;
+        lifetime_usec = link->network->router_dns_lifetime_usec;
+
+        if (search_domains)
+                goto set_domains;
+
+        lifetime_usec = SD_RADV_DEFAULT_DNS_LIFETIME_USEC;
+
+        search_domains = link->network->search_domains;
+        if (search_domains)
+                goto set_domains;
+
+        if (uplink) {
+                search_domains = uplink->network->search_domains;
+                if (search_domains)
+                        goto set_domains;
+        }
+
+        return 0;
+
+ set_domains:
+        return sd_radv_set_dnssl(link->radv,
+                                 DIV_ROUND_UP(lifetime_usec, USEC_PER_SEC),
+                                 search_domains);
+
+}
+
+int radv_emit_dns(Link *link) {
+        Link *uplink;
+        int r;
+
+        uplink = manager_find_uplink(link->manager, link);
+
+        r = radv_set_dns(link, uplink);
+        if (r < 0)
+                log_link_warning_errno(link, r, "Could not set RA DNS: %m");
+
+        r = radv_set_domains(link, uplink);
+        if (r < 0)
+                log_link_warning_errno(link, r, "Could not set RA Domains: %m");
+
+        return 0;
+}
+
 int radv_configure(Link *link) {
         int r;
         Prefix *p;
@@ -75,24 +206,5 @@ int radv_configure(Link *link) {
                         return r;
         }
 
-        if (link->network->router_dns) {
-                r = sd_radv_set_rdnss(link->radv,
-                                      DIV_ROUND_UP(link->network->router_dns_lifetime_usec,
-                                                   USEC_PER_SEC),
-                                      link->network->router_dns,
-                                      link->network->n_router_dns);
-                if (r < 0)
-                        return r;
-        }
-
-        if (link->network->router_search_domains) {
-                r = sd_radv_set_dnssl(link->radv,
-                                      DIV_ROUND_UP(link->network->router_dns_lifetime_usec,
-                                                   USEC_PER_SEC),
-                                      link->network->router_search_domains);
-                if (r < 0)
-                        return r;
-        }
-
-        return 0;
+        return radv_emit_dns(link);
 }
diff --git a/src/network/networkd-radv.h b/src/network/networkd-radv.h
index a186b111a1..d59373df9f 100644
--- a/src/network/networkd-radv.h
+++ b/src/network/networkd-radv.h
@@ -21,4 +21,5 @@
 
 #include "networkd-link.h"
 
+int radv_emit_dns(Link *link);
 int radv_configure(Link *link);
diff --git a/src/systemd/sd-radv.h b/src/systemd/sd-radv.h
index 0cc1d670b9..9805e3f24d 100644
--- a/src/systemd/sd-radv.h
+++ b/src/systemd/sd-radv.h
@@ -33,6 +33,11 @@
 
 _SD_BEGIN_DECLARATIONS;
 
+#define SD_RADV_DEFAULT_MIN_TIMEOUT_USEC        (200*USEC_PER_SEC)
+#define SD_RADV_DEFAULT_MAX_TIMEOUT_USEC        (600*USEC_PER_SEC)
+
+#define SD_RADV_DEFAULT_DNS_LIFETIME_USEC       (3*SD_RADV_DEFAULT_MAX_TIMEOUT_USEC)
+
 typedef struct sd_radv sd_radv;
 typedef struct sd_radv_prefix sd_radv_prefix;