Merge pull request #13070 from yuwata/network-set-route-to-dhcp-dns

11 files changed, 308 insertions, 64 deletions

diff --git a/man/systemd.network.xml b/man/systemd.network.xml
index cd1aa73f46..cdcca4aca8 100644
--- a/man/systemd.network.xml
+++ b/man/systemd.network.xml
@@ -1323,6 +1323,14 @@
           </listitem>
         </varlistentry>
         <varlistentry>
+          <term><varname>RoutesToDNS=</varname></term>
+          <listitem>
+            <para>When true, the routes to the DNS servers received from the DHCP server will be
+            configured. When <varname>UseDNS=</varname> is disabled, this setting is ignored.
+            Defaults to false.</para>
+          </listitem>
+        </varlistentry>
+        <varlistentry>
           <term><varname>UseNTP=</varname></term>
           <listitem>
             <para>When true (the default), the NTP servers received
diff --git a/src/network/networkd-dhcp4.c b/src/network/networkd-dhcp4.c
index 1bb1df32e9..f20254fc82 100644
--- a/src/network/networkd-dhcp4.c
+++ b/src/network/networkd-dhcp4.c
@@ -15,12 +15,13 @@
 #include "string-util.h"
 #include "sysctl-util.h"
 
-static int dhcp_remove_routes(Link *link, sd_dhcp_lease *lease, sd_dhcp_lease *new_lease, struct in_addr *address);
-static int dhcp_remove_router(Link *link, sd_dhcp_lease *lease, struct in_addr *address);
-static int dhcp_remove_address(Link *link, sd_dhcp_lease *lease, struct in_addr *address);
+static int dhcp_remove_routes(Link *link, sd_dhcp_lease *lease, const struct in_addr *address, bool remove_all);
+static int dhcp_remove_router(Link *link, sd_dhcp_lease *lease, const struct in_addr *address, bool remove_all);
+static int dhcp_remove_dns_routes(Link *link, sd_dhcp_lease *lease, const struct in_addr *address, bool remove_all);
+static int dhcp_remove_address(Link *link, sd_dhcp_lease *lease, const struct in_addr *address);
 
 void dhcp4_release_old_lease(Link *link) {
-        union in_addr_union address = IN_ADDR_NULL, address_old = IN_ADDR_NULL;
+        struct in_addr address = {}, address_old = {};
 
         assert(link);
 
@@ -29,15 +30,15 @@ void dhcp4_release_old_lease(Link *link) {
 
         assert(link->dhcp_lease);
 
-        (void) sd_dhcp_lease_get_address(link->dhcp_lease_old, &address_old.in);
-        (void) sd_dhcp_lease_get_address(link->dhcp_lease, &address.in);
+        (void) sd_dhcp_lease_get_address(link->dhcp_lease_old, &address_old);
+        (void) sd_dhcp_lease_get_address(link->dhcp_lease, &address);
 
-        (void) dhcp_remove_routes(link, link->dhcp_lease_old, link->dhcp_lease, &address_old.in);
+        (void) dhcp_remove_routes(link, link->dhcp_lease_old, &address_old, false);
+        (void) dhcp_remove_router(link, link->dhcp_lease_old, &address_old, false);
+        (void) dhcp_remove_dns_routes(link, link->dhcp_lease_old, &address_old, false);
 
-        if (!in_addr_equal(AF_INET, &address_old, &address)) {
-                (void) dhcp_remove_router(link, link->dhcp_lease_old, &address_old.in);
-                (void) dhcp_remove_address(link, link->dhcp_lease_old, &address_old.in);
-        }
+        if (!in4_addr_equal(&address_old, &address))
+                (void) dhcp_remove_address(link, link->dhcp_lease_old, &address_old);
 
         link->dhcp_lease_old = sd_dhcp_lease_unref(link->dhcp_lease_old);
         link_dirty(link);
@@ -84,6 +85,77 @@ static int route_scope_from_address(const Route *route, const struct in_addr *se
                 return RT_SCOPE_UNIVERSE;
 }
 
+static int dhcp_route_configure(Route **route, Link *link) {
+        int r;
+
+        assert(route);
+        assert(*route);
+        assert(link);
+
+        if (set_contains(link->dhcp_routes, *route))
+                return 0;
+
+        r = route_configure(*route, link, dhcp4_route_handler);
+        if (r <= 0)
+                return r;
+
+        link->dhcp4_messages++;
+
+        r = set_put(link->dhcp_routes, *route);
+        if (r < 0)
+                return r;
+
+        TAKE_PTR(*route);
+        return 0;
+}
+
+static int link_set_dns_routes(Link *link, const struct in_addr *address) {
+        const struct in_addr *dns;
+        uint32_t table;
+        int i, n, r;
+
+        assert(link);
+        assert(link->dhcp_lease);
+        assert(link->network);
+
+        if (!link->network->dhcp_use_dns ||
+            !link->network->dhcp_routes_to_dns)
+                return 0;
+
+        n = sd_dhcp_lease_get_dns(link->dhcp_lease, &dns);
+        if (IN_SET(n, 0, -ENODATA))
+                return 0;
+        if (n < 0)
+                return log_link_warning_errno(link, n, "DHCP error: could not get DNS servers: %m");
+
+        table = link_get_dhcp_route_table(link);
+
+        for (i = 0; i < n; i ++) {
+                _cleanup_(route_freep) Route *route = NULL;
+
+                r = route_new(&route);
+                if (r < 0)
+                        return log_link_error_errno(link, r,  "Could not allocate route: %m");
+
+                /* Set routes to DNS servers. */
+
+                route->family = AF_INET;
+                route->dst.in = dns[i];
+                route->dst_prefixlen = 32;
+                route->prefsrc.in = *address;
+                route->scope = RT_SCOPE_LINK;
+                route->protocol = RTPROT_DHCP;
+                route->priority = link->network->dhcp_route_metric;
+                route->table = table;
+
+                r = dhcp_route_configure(&route, link);
+                if (r < 0)
+                        return log_link_error_errno(link, r, "Could not set route to DNS server: %m");
+        }
+
+        return 0;
+}
+
 static int link_set_dhcp_routes(Link *link) {
         _cleanup_free_ sd_dhcp_route **static_routes = NULL;
         bool classless_route = false, static_route = false;
@@ -108,6 +180,13 @@ static int link_set_dhcp_routes(Link *link) {
                  * the addresses now, let's not configure the routes either. */
                 return 0;
 
+        r = set_ensure_allocated(&link->dhcp_routes, &route_full_hash_ops);
+        if (r < 0)
+                return log_oom();
+
+        /* Clear old entries in case the set was already allocated */
+        set_clear(link->dhcp_routes);
+
         table = link_get_dhcp_route_table(link);
 
         r = sd_dhcp_lease_get_address(link->dhcp_lease, &address);
@@ -155,11 +234,12 @@ static int link_set_dhcp_routes(Link *link) {
                 if (IN_SET(route->scope, RT_SCOPE_LINK, RT_SCOPE_UNIVERSE))
                         route->prefsrc.in = address;
 
-                r = route_configure(route, link, dhcp4_route_handler);
+                if (set_contains(link->dhcp_routes, route))
+                        continue;
+
+                r = dhcp_route_configure(&route, link);
                 if (r < 0)
-                        return log_link_error_errno(link, r, "Could not set host route: %m");
-                if (r > 0)
-                        link->dhcp4_messages++;
+                        return log_link_error_errno(link, r, "Could not set route: %m");
         }
 
         r = sd_dhcp_lease_get_router(link->dhcp_lease, &router);
@@ -194,11 +274,9 @@ static int link_set_dhcp_routes(Link *link) {
                 route_gw->priority = link->network->dhcp_route_metric;
                 route_gw->table = table;
 
-                r = route_configure(route_gw, link, dhcp4_route_handler);
+                r = dhcp_route_configure(&route_gw, link);
                 if (r < 0)
                         return log_link_error_errno(link, r, "Could not set host route: %m");
-                if (r > 0)
-                        link->dhcp4_messages++;
 
                 r = route_new(&route);
                 if (r < 0)
@@ -211,42 +289,18 @@ static int link_set_dhcp_routes(Link *link) {
                 route->priority = link->network->dhcp_route_metric;
                 route->table = table;
 
-                r = route_configure(route, link, dhcp4_route_handler);
+                r = dhcp_route_configure(&route, link);
                 if (r < 0)
-                        return log_link_error_errno(link, r, "Could not set routes: %m");
-                if (r > 0)
-                        link->dhcp4_messages++;
-        }
-
-        return 0;
-}
-
-static bool route_present_in_routes(const Route *route, sd_dhcp_route **routes, unsigned n_routes) {
-        assert(n_routes == 0 || routes);
-
-        for (unsigned j = 0; j < n_routes; j++) {
-                union in_addr_union a;
-                unsigned char l;
-
-                assert_se(sd_dhcp_route_get_gateway(routes[j], &a.in) >= 0);
-                if (!in_addr_equal(AF_INET, &a, &route->gw))
-                        continue;
-                assert_se(sd_dhcp_route_get_destination(routes[j], &a.in) >= 0);
-                if (!in_addr_equal(AF_INET, &a, &route->dst))
-                        continue;
-                assert_se(sd_dhcp_route_get_destination_prefix_length(routes[j], &l) >= 0);
-                if (l != route->dst_prefixlen)
-                        continue;
-                return true;
+                        return log_link_error_errno(link, r, "Could not set router: %m");
         }
 
-        return false;
+        return link_set_dns_routes(link, &address);
 }
 
-static int dhcp_remove_routes(Link *link, sd_dhcp_lease *lease, sd_dhcp_lease *new_lease, struct in_addr *address) {
-        _cleanup_free_ sd_dhcp_route **routes = NULL, **new_routes = NULL;
+static int dhcp_remove_routes(Link *link, sd_dhcp_lease *lease, const struct in_addr *address, bool remove_all) {
+        _cleanup_free_ sd_dhcp_route **routes = NULL;
         uint32_t table;
-        int m = 0, n, i, r;
+        int n, i, r;
 
         assert(link);
         assert(address);
@@ -260,14 +314,6 @@ static int dhcp_remove_routes(Link *link, sd_dhcp_lease *lease, sd_dhcp_lease *n
         else if (n < 0)
                 return log_link_error_errno(link, n, "DHCP error: Failed to get routes: %m");
 
-        if (new_lease) {
-                m = sd_dhcp_lease_get_routes(new_lease, &new_routes);
-                if (m == -ENODATA)
-                        m = 0;
-                else if (m < 0)
-                        return log_link_error_errno(link, m, "DHCP error: Failed to get routes: %m");
-        }
-
         table = link_get_dhcp_route_table(link);
 
         for (i = 0; i < n; i++) {
@@ -287,7 +333,7 @@ static int dhcp_remove_routes(Link *link, sd_dhcp_lease *lease, sd_dhcp_lease *n
                 if (IN_SET(route->scope, RT_SCOPE_LINK, RT_SCOPE_UNIVERSE))
                         route->prefsrc.in = *address;
 
-                if (route_present_in_routes(route, new_routes, m))
+                if (!remove_all && set_contains(link->dhcp_routes, route))
                         continue;
 
                 (void) route_remove(route, link, NULL);
@@ -296,7 +342,7 @@ static int dhcp_remove_routes(Link *link, sd_dhcp_lease *lease, sd_dhcp_lease *n
         return n;
 }
 
-static int dhcp_remove_router(Link *link, sd_dhcp_lease *lease, struct in_addr *address) {
+static int dhcp_remove_router(Link *link, sd_dhcp_lease *lease, const struct in_addr *address, bool remove_all) {
         _cleanup_(route_freep) Route *route_gw = NULL, *route = NULL;
         const struct in_addr *router;
         uint32_t table;
@@ -334,7 +380,8 @@ static int dhcp_remove_router(Link *link, sd_dhcp_lease *lease, struct in_addr *
         route_gw->priority = link->network->dhcp_route_metric;
         route_gw->table = table;
 
-        (void) route_remove(route_gw, link, NULL);
+        if (remove_all || !set_contains(link->dhcp_routes, route_gw))
+                (void) route_remove(route_gw, link, NULL);
 
         r = route_new(&route);
         if (r < 0)
@@ -347,12 +394,59 @@ static int dhcp_remove_router(Link *link, sd_dhcp_lease *lease, struct in_addr *
         route->priority = link->network->dhcp_route_metric;
         route->table = table;
 
-        (void) route_remove(route, link, NULL);
+        if (remove_all || !set_contains(link->dhcp_routes, route))
+                (void) route_remove(route, link, NULL);
+
+        return 0;
+}
+
+static int dhcp_remove_dns_routes(Link *link, sd_dhcp_lease *lease, const struct in_addr *address, bool remove_all) {
+        const struct in_addr *dns;
+        uint32_t table;
+        int i, n, r;
+
+        assert(link);
+        assert(lease);
+        assert(link->network);
+
+        if (!link->network->dhcp_use_dns ||
+            !link->network->dhcp_routes_to_dns)
+                return 0;
+
+        n = sd_dhcp_lease_get_dns(lease, &dns);
+        if (IN_SET(n, 0, -ENODATA))
+                return 0;
+        if (n < 0)
+                return log_link_warning_errno(link, n, "DHCP error: could not get DNS servers: %m");
+
+        table = link_get_dhcp_route_table(link);
+
+        for (i = 0; i < n; i ++) {
+                _cleanup_(route_freep) Route *route = NULL;
+
+                r = route_new(&route);
+                if (r < 0)
+                        return log_link_error_errno(link, r,  "Could not allocate route: %m");
+
+                route->family = AF_INET;
+                route->dst.in = dns[i];
+                route->dst_prefixlen = 32;
+                route->prefsrc.in = *address;
+                route->scope = RT_SCOPE_LINK;
+                route->protocol = RTPROT_DHCP;
+                route->priority = link->network->dhcp_route_metric;
+                route->table = table;
+
+                if (!remove_all && set_contains(link->dhcp_routes, route))
+                        continue;
+
+                (void) route_remove(route, link, NULL);
+        }
 
         return 0;
 }
 
-static int dhcp_remove_address(Link *link, sd_dhcp_lease *lease, struct in_addr *address) {
+static int dhcp_remove_address(Link *link, sd_dhcp_lease *lease, const struct in_addr *address) {
         _cleanup_(address_freep) Address *a = NULL;
         struct in_addr netmask;
         int r;
@@ -439,8 +533,9 @@ static int dhcp_lease_lost(Link *link) {
         link->dhcp4_configured = false;
 
         (void) sd_dhcp_lease_get_address(link->dhcp_lease, &address);
-        (void) dhcp_remove_routes(link, link->dhcp_lease, NULL, &address);
-        (void) dhcp_remove_router(link, link->dhcp_lease, &address);
+        (void) dhcp_remove_routes(link, link->dhcp_lease, &address, true);
+        (void) dhcp_remove_router(link, link->dhcp_lease, &address, true);
+        (void) dhcp_remove_dns_routes(link, link->dhcp_lease, &address, true);
         (void) dhcp_remove_address(link, link->dhcp_lease, &address);
         (void) dhcp_reset_mtu(link);
         (void) dhcp_reset_hostname(link);
diff --git a/src/network/networkd-link.c b/src/network/networkd-link.c
index 63f7422096..8ca4583034 100644
--- a/src/network/networkd-link.c
+++ b/src/network/networkd-link.c
@@ -703,6 +703,7 @@ static Link *link_free(Link *link) {
         sd_dhcp_server_unref(link->dhcp_server);
         sd_dhcp_client_unref(link->dhcp_client);
         sd_dhcp_lease_unref(link->dhcp_lease);
+        set_free(link->dhcp_routes);
 
         link_lldp_emit_stop(link);
 
diff --git a/src/network/networkd-link.h b/src/network/networkd-link.h
index bfdcef0e50..cd88388015 100644
--- a/src/network/networkd-link.h
+++ b/src/network/networkd-link.h
@@ -83,6 +83,7 @@ typedef struct Link {
 
         sd_dhcp_client *dhcp_client;
         sd_dhcp_lease *dhcp_lease, *dhcp_lease_old;
+        Set *dhcp_routes;
         char *lease_file;
         uint32_t original_mtu;
         unsigned dhcp4_messages;
diff --git a/src/network/networkd-network-gperf.gperf b/src/network/networkd-network-gperf.gperf
index 3501ffdd10..f5f837ad63 100644
--- a/src/network/networkd-network-gperf.gperf
+++ b/src/network/networkd-network-gperf.gperf
@@ -142,6 +142,7 @@ Route.FastOpenNoCookie,                 config_parse_fast_open_no_cookie,
 Route.TTLPropagate,                     config_parse_route_ttl_propagate,                0,                             0
 DHCPv4.ClientIdentifier,                config_parse_dhcp_client_identifier,             0,                             offsetof(Network, dhcp_client_identifier)
 DHCPv4.UseDNS,                          config_parse_bool,                               0,                             offsetof(Network, dhcp_use_dns)
+DHCPv4.RoutesToDNS,                     config_parse_bool,                               0,                             offsetof(Network, dhcp_routes_to_dns)
 DHCPv4.UseNTP,                          config_parse_bool,                               0,                             offsetof(Network, dhcp_use_ntp)
 DHCPv4.UseMTU,                          config_parse_bool,                               0,                             offsetof(Network, dhcp_use_mtu)
 DHCPv4.UseHostname,                     config_parse_bool,                               0,                             offsetof(Network, dhcp_use_hostname)
diff --git a/src/network/networkd-network.h b/src/network/networkd-network.h
index 82fad492a8..0fa800841c 100644
--- a/src/network/networkd-network.h
+++ b/src/network/networkd-network.h
@@ -91,6 +91,7 @@ struct Network {
         bool dhcp_broadcast;
         int dhcp_critical;
         bool dhcp_use_dns;
+        bool dhcp_routes_to_dns;
         bool dhcp_use_ntp;
         bool dhcp_use_mtu;
         bool dhcp_use_routes;
diff --git a/src/network/networkd-route.c b/src/network/networkd-route.c
index a4b56ab46b..25ab527284 100644
--- a/src/network/networkd-route.c
+++ b/src/network/networkd-route.c
@@ -207,6 +207,103 @@ static int route_compare_func(const Route *a, const Route *b) {
 
 DEFINE_PRIVATE_HASH_OPS(route_hash_ops, Route, route_hash_func, route_compare_func);
 
+static void route_full_hash_func(const Route *route, struct siphash *state) {
+        assert(route);
+
+        siphash24_compress(&route->family, sizeof(route->family), state);
+
+        switch (route->family) {
+        case AF_INET:
+        case AF_INET6:
+                siphash24_compress(&route->gw, FAMILY_ADDRESS_SIZE(route->family), state);
+                siphash24_compress(&route->dst, FAMILY_ADDRESS_SIZE(route->family), state);
+                siphash24_compress(&route->dst_prefixlen, sizeof(route->dst_prefixlen), state);
+                siphash24_compress(&route->src, FAMILY_ADDRESS_SIZE(route->family), state);
+                siphash24_compress(&route->src_prefixlen, sizeof(route->src_prefixlen), state);
+                siphash24_compress(&route->prefsrc, FAMILY_ADDRESS_SIZE(route->family), state);
+
+                siphash24_compress(&route->tos, sizeof(route->tos), state);
+                siphash24_compress(&route->priority, sizeof(route->priority), state);
+                siphash24_compress(&route->table, sizeof(route->table), state);
+                siphash24_compress(&route->protocol, sizeof(route->protocol), state);
+                siphash24_compress(&route->scope, sizeof(route->scope), state);
+                siphash24_compress(&route->type, sizeof(route->type), state);
+
+                break;
+        default:
+                /* treat any other address family as AF_UNSPEC */
+                break;
+        }
+}
+
+static int route_full_compare_func(const Route *a, const Route *b) {
+        int r;
+
+        r = CMP(a->family, b->family);
+        if (r != 0)
+                return r;
+
+        switch (a->family) {
+        case AF_INET:
+        case AF_INET6:
+                r = CMP(a->dst_prefixlen, b->dst_prefixlen);
+                if (r != 0)
+                        return r;
+
+                r = CMP(a->src_prefixlen, b->src_prefixlen);
+                if (r != 0)
+                        return r;
+
+                r = CMP(a->tos, b->tos);
+                if (r != 0)
+                        return r;
+
+                r = CMP(a->priority, b->priority);
+                if (r != 0)
+                        return r;
+
+                r = CMP(a->table, b->table);
+                if (r != 0)
+                        return r;
+
+                r = CMP(a->protocol, b->protocol);
+                if (r != 0)
+                        return r;
+
+                r = CMP(a->scope, b->scope);
+                if (r != 0)
+                        return r;
+
+                r = CMP(a->type, b->type);
+                if (r != 0)
+                        return r;
+
+                r = memcmp(&a->gw, &b->gw, FAMILY_ADDRESS_SIZE(a->family));
+                if (r != 0)
+                        return r;
+
+                r = memcmp(&a->dst, &b->dst, FAMILY_ADDRESS_SIZE(a->family));
+                if (r != 0)
+                        return r;
+
+                r = memcmp(&a->src, &b->src, FAMILY_ADDRESS_SIZE(a->family));
+                if (r != 0)
+                        return r;
+
+                return memcmp(&a->prefsrc, &b->prefsrc, FAMILY_ADDRESS_SIZE(a->family));
+        default:
+                /* treat any other address family as AF_UNSPEC */
+                return 0;
+        }
+}
+
+DEFINE_HASH_OPS_WITH_KEY_DESTRUCTOR(
+                route_full_hash_ops,
+                Route,
+                route_full_hash_func,
+                route_full_compare_func,
+                route_free);
+
 bool route_equal(Route *r1, Route *r2) {
         if (r1 == r2)
                 return true;
diff --git a/src/network/networkd-route.h b/src/network/networkd-route.h
index fda7ddedfa..9d9c980d90 100644
--- a/src/network/networkd-route.h
+++ b/src/network/networkd-route.h
@@ -49,6 +49,8 @@ struct Route {
         LIST_FIELDS(Route, routes);
 };
 
+extern const struct hash_ops route_full_hash_ops;
+
 int route_new(Route **ret);
 void route_free(Route *route);
 int route_configure(Route *route, Link *link, link_netlink_message_handler_t callback);
diff --git a/test/fuzz/fuzz-network-parser/directives.network b/test/fuzz/fuzz-network-parser/directives.network
index 69a4281542..c3af95db0d 100644
--- a/test/fuzz/fuzz-network-parser/directives.network
+++ b/test/fuzz/fuzz-network-parser/directives.network
@@ -69,6 +69,7 @@ SendRelease=
 MaxAttempts=
 [DHCPv4]
 UseDNS=
+RoutesToDNS=
 UseDomains=
 UseRoutes=
 IAID=
diff --git a/test/test-network/conf/dhcp-client-ipv4-only-ipv6-disabled.network b/test/test-network/conf/dhcp-client-ipv4-only-ipv6-disabled.network
index c980bf9fca..b0d0d8605e 100644
--- a/test/test-network/conf/dhcp-client-ipv4-only-ipv6-disabled.network
+++ b/test/test-network/conf/dhcp-client-ipv4-only-ipv6-disabled.network
@@ -4,3 +4,6 @@ Name=veth99
 [Network]
 DHCP=ipv4
 IPv6AcceptRA=false
+
+[DHCPv4]
+RoutesToDNS=yes
diff --git a/test/test-network/systemd-networkd-tests.py b/test/test-network/systemd-networkd-tests.py
index 2f13bc2bbb..d73895aeab 100755
--- a/test/test-network/systemd-networkd-tests.py
+++ b/test/test-network/systemd-networkd-tests.py
@@ -2391,13 +2391,47 @@ class NetworkdDHCPClientTests(unittest.TestCase, Utilities):
 
         start_networkd()
         self.wait_online(['veth-peer:carrier'])
-        start_dnsmasq()
+        start_dnsmasq(additional_options='--dhcp-option=option:dns-server,192.168.5.6,192.168.5.7', lease_time='2m')
+        self.wait_online(['veth99:routable', 'veth-peer:routable'])
+
+        output = check_output(*networkctl_cmd, 'status', 'veth99', env=env)
+        print(output)
+        self.assertNotRegex(output, '2600::')
+        self.assertRegex(output, '192.168.5')
+        self.assertRegex(output, '192.168.5.6')
+        self.assertRegex(output, '192.168.5.7')
+
+        # checking routes to DNS servers
+        output = check_output('ip route show dev veth99')
+        print(output)
+        self.assertRegex(output, r'192.168.5.1 proto dhcp scope link src 192.168.5.181 metric 1024')
+        self.assertRegex(output, r'192.168.5.6 proto dhcp scope link src 192.168.5.181 metric 1024')
+        self.assertRegex(output, r'192.168.5.7 proto dhcp scope link src 192.168.5.181 metric 1024')
+
+        stop_dnsmasq(dnsmasq_pid_file)
+        start_dnsmasq(additional_options='--dhcp-option=option:dns-server,192.168.5.1,192.168.5.7,192.168.5.8', lease_time='2m')
+
+        # Sleep for 120 sec as the dnsmasq minimum lease time can only be set to 120
+        print('Wait for the dynamic address to be renewed')
+        time.sleep(125)
+
         self.wait_online(['veth99:routable', 'veth-peer:routable'])
 
         output = check_output(*networkctl_cmd, 'status', 'veth99', env=env)
         print(output)
         self.assertNotRegex(output, '2600::')
         self.assertRegex(output, '192.168.5')
+        self.assertNotRegex(output, '192.168.5.6')
+        self.assertRegex(output, '192.168.5.7')
+        self.assertRegex(output, '192.168.5.8')
+
+        # checking routes to DNS servers
+        output = check_output('ip route show dev veth99')
+        print(output)
+        self.assertNotRegex(output, r'192.168.5.6')
+        self.assertRegex(output, r'192.168.5.1 proto dhcp scope link src 192.168.5.181 metric 1024')
+        self.assertRegex(output, r'192.168.5.7 proto dhcp scope link src 192.168.5.181 metric 1024')
+        self.assertRegex(output, r'192.168.5.8 proto dhcp scope link src 192.168.5.181 metric 1024')
 
     def test_dhcp_client_ipv4_ipv6(self):
         copy_unit_to_networkd_unit_path('25-veth.netdev', 'dhcp-server-veth-peer.network', 'dhcp-client-ipv6-only.network',