sd-bus: break the loop in bus_ensure_running() if the bus is not connecting

This might fix #17025:
> the call trace is
> bus_ensure_running -> sd_bus_process -> bus_process_internal -> process_closeing --> sd_bus_close
>                                                                                  |
>                                                                                  \-> process_match

We ended doing callouts to the Disconnected matches from bus_ensure_running()
and shouldn't. bus_ensure_running() should never do callouts. This change
should fix this however: once we notice that the connection is going down we
will now fail instantly with ENOTOCONN instead of calling any callbacks.

man/systemd.network.xml

@@ -1283,9 +1283,8 @@ IPv6Token=prefixstable:2002:da8:1::</programlisting></para>
           <term><varname>Gateway=</varname></term>
           <listitem>
             <para>Takes the gateway address or the special values <literal>_dhcp4</literal> and
-            <literal>_dhcp6</literal>. If <literal>_dhcp4</literal> or <literal>_dhcp6</literal> is
-            set, then the gateway address provided by DHCP (or in the IPv6 case, provided by IPv6 RA)
-            is used.</para>
+            <literal>_ipv6ra</literal>. If <literal>_dhcp4</literal> or <literal>_ipv6ra</literal> is
+            set, then the gateway address provided by DHCPv4 or IPv6 RA is used.</para>
           </listitem>
         </varlistentry>
          <varlistentry>

src/libsystemd/sd-bus/sd-bus.c

@@ -2120,12 +2120,13 @@ int bus_ensure_running(sd_bus *bus) {
 
         assert(bus);
 
-        if (IN_SET(bus->state, BUS_UNSET, BUS_CLOSED, BUS_CLOSING))
-                return -ENOTCONN;
         if (bus->state == BUS_RUNNING)
                 return 1;
 
         for (;;) {
+                if (IN_SET(bus->state, BUS_UNSET, BUS_CLOSED, BUS_CLOSING))
+                        return -ENOTCONN;
+
                 r = sd_bus_process(bus, NULL);
                 if (r < 0)
                         return r;

src/network/networkd-dhcp-common.c

@@ -26,18 +26,38 @@ bool link_dhcp_enabled(Link *link, int family) {
         if (link->flags & IFF_LOOPBACK)
                 return false;
 
-        if (!link->network)
-                return false;
-
-        if (link->network->bond)
-                return false;
-
         if (link->iftype == ARPHRD_CAN)
                 return false;
 
+        if (!link->network)
+                return false;
+
         return link->network->dhcp & (family == AF_INET ? ADDRESS_FAMILY_IPV4 : ADDRESS_FAMILY_IPV6);
 }
 
+void network_adjust_dhcp(Network *network) {
+        assert(network);
+        assert(network->dhcp >= 0);
+
+        if (network->dhcp == ADDRESS_FAMILY_NO)
+                return;
+
+        /* Bonding slave does not support addressing. */
+        if (network->bond) {
+                log_warning("%s: Cannot enable DHCP= when Bond= is specified, disabling DHCP=.",
+                            network->filename);
+                network->dhcp = ADDRESS_FAMILY_NO;
+                return;
+        }
+
+        if (!FLAGS_SET(network->link_local, ADDRESS_FAMILY_IPV6) &&
+            FLAGS_SET(network->dhcp, ADDRESS_FAMILY_IPV6)) {
+                log_warning("%s: DHCPv6 client is enabled but IPv6 link local addressing is disabled. "
+                            "Disabling DHCPv6 client.", network->filename);
+                SET_FLAG(network->dhcp, ADDRESS_FAMILY_IPV6, false);
+        }
+}
+
 DUID* link_get_duid(Link *link) {
         if (link->network->duid.type != _DUID_TYPE_INVALID)
                 return &link->network->duid;

src/network/networkd-dhcp-common.h

@@ -9,6 +9,7 @@
 
 typedef struct Link Link;
 typedef struct Manager Manager;
+typedef struct Network Network;
 
 typedef enum DHCPUseDomains {
         DHCP_USE_DOMAINS_NO,
@@ -46,6 +47,8 @@ static inline bool link_dhcp6_enabled(Link *link) {
         return link_dhcp_enabled(link, AF_INET6);
 }
 
+void network_adjust_dhcp(Network *network);
+
 DUID* link_get_duid(Link *link);
 int link_configure_duid(Link *link);
 int manager_request_product_uuid(Manager *m, Link *link);

src/network/networkd-dhcp4.c

@@ -388,14 +388,21 @@ static int link_set_dhcp_routes(Link *link) {
                                 return log_link_error_errno(link, r, "Could not set router: %m");
 
                         HASHMAP_FOREACH(rt, link->network->routes_by_section) {
-                                if (!rt->gateway_from_dhcp)
+                                if (!rt->gateway_from_dhcp_or_ra)
                                         continue;
 
-                                if (rt->family != AF_INET)
+                                if (rt->gw_family != AF_INET)
                                         continue;
 
-                                rt->gw_family = AF_INET;
                                 rt->gw.in = router[0];
+                                if (!rt->protocol_set)
+                                        rt->protocol = RTPROT_DHCP;
+                                if (!rt->priority_set)
+                                        rt->priority = link->network->dhcp_route_metric;
+                                if (!rt->table_set)
+                                        rt->table = table;
+                                if (rt->mtu == 0)
+                                        rt->mtu = link->network->dhcp_route_mtu;
 
                                 r = dhcp_route_configure(rt, link);
                                 if (r < 0)

src/network/networkd-ndisc.c

@@ -14,7 +14,6 @@
 #include "networkd-dhcp6.h"
 #include "networkd-manager.h"
 #include "networkd-ndisc.h"
-#include "networkd-sysctl.h"
 #include "string-table.h"
 #include "string-util.h"
 #include "strv.h"
@@ -52,19 +51,23 @@ bool link_ipv6_accept_ra_enabled(Link *link) {
         if (!link_ipv6ll_enabled(link))
                 return false;
 
-        /* If unset use system default (enabled if local forwarding is disabled.
-         * disabled if local forwarding is enabled).
-         * If set, ignore or enforce RA independent of local forwarding state.
-         */
-        if (link->network->ipv6_accept_ra < 0)
+        assert(link->network->ipv6_accept_ra >= 0);
+        return link->network->ipv6_accept_ra;
+}
+
+void network_adjust_ipv6_accept_ra(Network *network) {
+        assert(network);
+
+        if (!FLAGS_SET(network->link_local, ADDRESS_FAMILY_IPV6)) {
+                if (network->ipv6_accept_ra > 0)
+                        log_warning("%s: IPv6AcceptRA= is enabled but IPv6 link local addressing is disabled or not supported. "
+                                    "Disabling IPv6AcceptRA=.", network->filename);
+                network->ipv6_accept_ra = false;
+        }
+
+        if (network->ipv6_accept_ra < 0)
                 /* default to accept RA if ip_forward is disabled and ignore RA if ip_forward is enabled */
-                return !link_ip_forward_enabled(link, AF_INET6);
-        else if (link->network->ipv6_accept_ra > 0)
-                /* accept RA even if ip_forward is enabled */
-                return true;
-        else
-                /* ignore RA */
-                return false;
+                network->ipv6_accept_ra = !FLAGS_SET(network->ip_forward, ADDRESS_FAMILY_IPV6);
 }
 
 static int ndisc_remove_old_one(Link *link, const struct in6_addr *router, bool force);
@@ -461,7 +464,7 @@ static int ndisc_router_process_default(Link *link, sd_ndisc_router *rt) {
         union in_addr_union gateway;
         uint16_t lifetime;
         unsigned preference;
-        uint32_t mtu;
+        uint32_t table, mtu;
         usec_t time_now;
         int r;
 
@@ -504,12 +507,14 @@ static int ndisc_router_process_default(Link *link, sd_ndisc_router *rt) {
         else if (r < 0)
                 return log_link_error_errno(link, r, "Failed to get default router MTU from RA: %m");
 
+        table = link_get_ipv6_accept_ra_route_table(link);
+
         r = route_new(&route);
         if (r < 0)
                 return log_oom();
 
         route->family = AF_INET6;
-        route->table = link_get_ipv6_accept_ra_route_table(link);
+        route->table = table;
         route->priority = link->network->dhcp6_route_metric;
         route->protocol = RTPROT_RA;
         route->pref = preference;
@@ -524,14 +529,24 @@ static int ndisc_router_process_default(Link *link, sd_ndisc_router *rt) {
 
         Route *route_gw;
         HASHMAP_FOREACH(route_gw, link->network->routes_by_section) {
-                if (!route_gw->gateway_from_dhcp)
+                if (!route_gw->gateway_from_dhcp_or_ra)
                         continue;
 
-                if (route_gw->family != AF_INET6)
+                if (route_gw->gw_family != AF_INET6)
                         continue;
 
                 route_gw->gw = gateway;
-                route_gw->gw_family = AF_INET6;
+                if (!route_gw->table_set)
+                        route_gw->table = table;
+                if (!route_gw->priority_set)
+                        route_gw->priority = link->network->dhcp6_route_metric;
+                if (!route_gw->protocol_set)
+                        route_gw->protocol = RTPROT_RA;
+                if (!route_gw->pref_set)
+                        route->pref = preference;
+                route_gw->lifetime = time_now + lifetime * USEC_PER_SEC;
+                if (route_gw->mtu == 0)
+                        route_gw->mtu = mtu;
 
                 r = ndisc_route_configure(route_gw, link, rt);
                 if (r < 0)

src/network/networkd-ndisc.h

@@ -71,6 +71,8 @@ static inline char* NDISC_DNSSL_DOMAIN(const NDiscDNSSL *n) {
 
 bool link_ipv6_accept_ra_enabled(Link *link);
 
+void network_adjust_ipv6_accept_ra(Network *network);
+
 int ndisc_configure(Link *link);
 void ndisc_vacuum(Link *link);
 void ndisc_flush(Link *link);

src/network/networkd-network.c

@@ -16,9 +16,11 @@
 #include "network-internal.h"
 #include "networkd-address-label.h"
 #include "networkd-address.h"
+#include "networkd-dhcp-common.h"
 #include "networkd-fdb.h"
 #include "networkd-manager.h"
 #include "networkd-mdb.h"
+#include "networkd-ndisc.h"
 #include "networkd-neighbor.h"
 #include "networkd-network.h"
 #include "networkd-nexthop.h"
@@ -188,21 +190,11 @@ int network_verify(Network *network) {
 
         if (network->bond) {
                 /* Bonding slave does not support addressing. */
-                if (network->ipv6_accept_ra > 0) {
-                        log_warning("%s: Cannot enable IPv6AcceptRA= when Bond= is specified, disabling IPv6AcceptRA=.",
-                                    network->filename);
-                        network->ipv6_accept_ra = 0;
-                }
                 if (network->link_local >= 0 && network->link_local != ADDRESS_FAMILY_NO) {
                         log_warning("%s: Cannot enable LinkLocalAddressing= when Bond= is specified, disabling LinkLocalAddressing=.",
                                     network->filename);
                         network->link_local = ADDRESS_FAMILY_NO;
                 }
-                if (network->dhcp != ADDRESS_FAMILY_NO) {
-                        log_warning("%s: Cannot enable DHCP= when Bond= is specified, disabling DHCP=.",
-                                    network->filename);
-                        network->dhcp = ADDRESS_FAMILY_NO;
-                }
                 if (network->dhcp_server) {
                         log_warning("%s: Cannot enable DHCPServer= when Bond= is specified, disabling DHCPServer=.",
                                     network->filename);
@@ -223,18 +215,6 @@ int network_verify(Network *network) {
                 network->link_local = network->bridge ? ADDRESS_FAMILY_NO : ADDRESS_FAMILY_IPV6;
 
         if (!FLAGS_SET(network->link_local, ADDRESS_FAMILY_IPV6)) {
-                if (network->ipv6_accept_ra > 0) {
-                        log_warning("%s: IPv6AcceptRA= is enabled by the .network file but IPv6 link local addressing is disabled. "
-                                    "Disabling IPv6AcceptRA=.", network->filename);
-                        network->ipv6_accept_ra = false;
-                }
-
-                if (FLAGS_SET(network->dhcp, ADDRESS_FAMILY_IPV6)) {
-                        log_warning("%s: DHCPv6 client is enabled by the .network file but IPv6 link local addressing is disabled. "
-                                    "Disabling DHCPv6 client.", network->filename);
-                        SET_FLAG(network->dhcp, ADDRESS_FAMILY_IPV6, false);
-                }
-
                 if (network->router_prefix_delegation != RADV_PREFIX_DELEGATION_NONE) {
                         log_warning("%s: IPv6PrefixDelegation= is enabled but IPv6 link local addressing is disabled. "
                                     "Disabling IPv6PrefixDelegation=.", network->filename);
@@ -249,13 +229,13 @@ int network_verify(Network *network) {
                 SET_FLAG(network->link_local, ADDRESS_FAMILY_FALLBACK_IPV4, false);
         }
 
-        if (network->ipv6_accept_ra < 0 && network->bridge)
-                network->ipv6_accept_ra = false;
-
         /* IPMasquerade=yes implies IPForward=yes */
         if (network->ip_masquerade)
                 network->ip_forward |= ADDRESS_FAMILY_IPV4;
 
+        network_adjust_ipv6_accept_ra(network);
+        network_adjust_dhcp(network);
+
         if (network->mtu > 0 && network->dhcp_use_mtu) {
                 log_warning("%s: MTUBytes= in [Link] section and UseMTU= in [DHCP] section are set. "
                             "Disabling UseMTU=.", network->filename);

src/network/networkd-route.c

@@ -1192,7 +1192,7 @@ int link_set_routes(Link *link) {
         /* First add the routes that enable us to talk to gateways, then add in the others that need a gateway. */
         for (phase = 0; phase < _PHASE_MAX; phase++)
                 HASHMAP_FOREACH(rt, link->network->routes_by_section) {
-                        if (rt->gateway_from_dhcp)
+                        if (rt->gateway_from_dhcp_or_ra)
                                 continue;
 
                         if ((in_addr_is_null(rt->gw_family, &rt->gw) && ordered_set_isempty(rt->multipath_routes)) != (phase == PHASE_NON_GATEWAY))
@@ -1723,7 +1723,7 @@ int config_parse_gateway(
                 }
 
                 if (isempty(rvalue)) {
-                        n->gateway_from_dhcp = false;
+                        n->gateway_from_dhcp_or_ra = false;
                         n->gw_family = AF_UNSPEC;
                         n->gw = IN_ADDR_NULL;
                         TAKE_PTR(n);
@@ -1731,21 +1731,21 @@ int config_parse_gateway(
                 }
 
                 if (streq(rvalue, "_dhcp")) {
-                        n->gateway_from_dhcp = true;
+                        n->gateway_from_dhcp_or_ra = true;
                         TAKE_PTR(n);
                         return 0;
                 }
 
                 if (streq(rvalue, "_dhcp4")) {
                         n->gw_family = AF_INET;
-                        n->gateway_from_dhcp = true;
+                        n->gateway_from_dhcp_or_ra = true;
                         TAKE_PTR(n);
                         return 0;
                 }
 
-                if (streq(rvalue, "_dhcp6")) {
+                if (streq(rvalue, "_ipv6ra")) {
                         n->gw_family = AF_INET6;
-                        n->gateway_from_dhcp = true;
+                        n->gateway_from_dhcp_or_ra = true;
                         TAKE_PTR(n);
                         return 0;
                 }
@@ -1758,7 +1758,7 @@ int config_parse_gateway(
                 return 0;
         }
 
-        n->gateway_from_dhcp = false;
+        n->gateway_from_dhcp_or_ra = false;
         TAKE_PTR(n);
         return 0;
 }
@@ -1902,6 +1902,7 @@ int config_parse_route_priority(
                 return 0;
         }
 
+        n->priority_set = true;
         TAKE_PTR(n);
         return 0;
 }
@@ -2086,6 +2087,7 @@ int config_parse_ipv6_route_preference(
                 return 0;
         }
 
+        n->pref_set = true;
         TAKE_PTR(n);
         return 0;
 }
@@ -2380,20 +2382,50 @@ static int route_section_verify(Route *route, Network *network) {
         if (section_is_invalid(route->section))
                 return -EINVAL;
 
+        if (route->gateway_from_dhcp_or_ra) {
+                if (route->gw_family == AF_UNSPEC) {
+                        /* When deprecated Gateway=_dhcp is set, then assume gateway family based on other settings. */
+                        switch (route->family) {
+                        case AF_UNSPEC:
+                                log_warning("%s: Deprecated value \"_dhcp\" is specified for Gateway= in [Route] section from line %u. "
+                                            "Please use \"_dhcp4\" or \"_ipv6ra\" instead. Assuming \"_dhcp4\".",
+                                            route->section->filename, route->section->line);
+                                route->family = AF_INET;
+                                break;
+                        case AF_INET:
+                        case AF_INET6:
+                                log_warning("%s: Deprecated value \"_dhcp\" is specified for Gateway= in [Route] section from line %u. "
+                                            "Assuming \"%s\" based on Destination=, Source=, or PreferredSource= setting.",
+                                            route->section->filename, route->section->line, route->family == AF_INET ? "_dhcp4" : "_ipv6ra");
+                                break;
+                        default:
+                                return log_warning_errno(SYNTHETIC_ERRNO(EINVAL),
+                                                         "%s: Invalid route family. Ignoring [Route] section from line %u.",
+                                                         route->section->filename, route->section->line);
+                        }
+                        route->gw_family = route->family;
+                }
+
+                if (route->gw_family == AF_INET && !FLAGS_SET(network->dhcp, ADDRESS_FAMILY_IPV4))
+                        return log_warning_errno(SYNTHETIC_ERRNO(EINVAL),
+                                                 "%s: Gateway=\"_dhcp4\" is specified but DHCPv4 client is disabled. "
+                                                 "Ignoring [Route] section from line %u.",
+                                                 route->section->filename, route->section->line);
+
+                if (route->gw_family == AF_INET6 && !network->ipv6_accept_ra)
+                        return log_warning_errno(SYNTHETIC_ERRNO(EINVAL),
+                                                 "%s: Gateway=\"_ipv6ra\" is specified but IPv6AcceptRA= is disabled. "
+                                                 "Ignoring [Route] section from line %u.",
+                                                 route->section->filename, route->section->line);
+        }
+
+        /* When only Gateway= is specified, assume the route family based on the Gateway address. */
         if (route->family == AF_UNSPEC)
                 route->family = route->gw_family;
 
         if (route->family == AF_UNSPEC) {
                 assert(route->section);
 
-                if (route->gateway_from_dhcp) {
-                        log_warning("%s: Deprecated value \"_dhcp\" is specified for Gateway= in [Route] section from line %u. "
-                                    "Please use \"_dhcp4\" or \"_dhcp6\" instead. Assuming \"_dhcp4\".",
-                                    route->section->filename, route->section->line);
-
-                        route->family = AF_INET;
-                        route->gw_family = AF_INET;
-                } else
                 return log_warning_errno(SYNTHETIC_ERRNO(EINVAL),
                                          "%s: Route section without Gateway=, Destination=, Source=, "
                                          "or PreferredSource= field configured. "

src/network/networkd-route.h

@@ -32,20 +32,24 @@ typedef struct Route {
         unsigned char dst_prefixlen;
         unsigned char src_prefixlen;
         unsigned char scope;
-        bool scope_set;
         unsigned char protocol;  /* RTPROT_* */
         unsigned char type; /* RTN_* */
         unsigned char tos;
         uint32_t priority; /* note that ip(8) calls this 'metric' */
         uint32_t table;
-        bool table_set;
         uint32_t mtu;
         uint32_t initcwnd;
         uint32_t initrwnd;
         unsigned char pref;
         unsigned flags;
         int gateway_onlink;
-        bool gateway_from_dhcp;
+
+        bool scope_set:1;
+        bool table_set:1;
+        bool priority_set:1;
+        bool protocol_set:1;
+        bool pref_set:1;
+        bool gateway_from_dhcp_or_ra:1;
 
         union in_addr_union gw;
         union in_addr_union dst;

src/network/networkd-sysctl.c

@@ -38,7 +38,7 @@ static int link_set_proxy_arp(Link *link) {
         return sysctl_write_ip_property_boolean(AF_INET, link->ifname, "proxy_arp", link->network->proxy_arp > 0);
 }
 
-bool link_ip_forward_enabled(Link *link, int family) {
+static bool link_ip_forward_enabled(Link *link, int family) {
         assert(link);
         assert(IN_SET(family, AF_INET, AF_INET6));
 

src/network/networkd-sysctl.h

@@ -16,7 +16,6 @@ typedef enum IPv6PrivacyExtensions {
         _IPV6_PRIVACY_EXTENSIONS_INVALID = -1,
 } IPv6PrivacyExtensions;
 
-bool link_ip_forward_enabled(Link *link, int family);
 int link_set_sysctl(Link *link);
 int link_set_ipv6_mtu(Link *link);
 

test/test-network/conf/dhcp-client-gateway-ipv4.network

@@ -6,5 +6,5 @@ DHCP=ipv4
 IPv6AcceptRA=no
 
 [Route]
-Gateway=_dhcp
+Gateway=_dhcp4
 Destination=10.0.0.0/8

test/test-network/conf/dhcp-client-gateway-ipv6.network

@@ -5,5 +5,5 @@ Name=veth99
 DHCP=ipv6
 
 [Route]
-Gateway=_dhcp
+Gateway=_ipv6ra
 Destination=2001:1234:5:9fff:ff:ff:ff:ff/128

test/test-network/systemd-networkd-tests.py

@@ -3899,7 +3899,7 @@ class NetworkdDHCPClientTests(unittest.TestCase, Utilities):
 
         output = check_output('ip route list dev veth99 10.0.0.0/8')
         print(output)
-        self.assertRegex(output, '10.0.0.0/8 via 192.168.5.1 proto static')
+        self.assertRegex(output, '10.0.0.0/8 via 192.168.5.1 proto dhcp')
 
     def test_dhcp_client_gateway_ipv6(self):
         copy_unit_to_networkd_unit_path('25-veth.netdev', 'dhcp-server-veth-peer.network',