optionally set socket priority on DHCPv4 raw socket

src/network/networkd-dhcp4.c

@@ -1499,6 +1499,12 @@ static int dhcp4_configure(Link *link) {
                         return log_link_debug_errno(link, r, "DHCPv4 CLIENT: Failed to set IP service type: %m");
         }
 
+        if (link->network->dhcp_socket_priority_set) {
+                r = sd_dhcp_client_set_socket_priority(link->dhcp_client, link->network->dhcp_socket_priority);
+                if (r < 0)
+                        return log_link_debug_errno(link, r, "DHCPv4 CLIENT: Failed to set socket priority: %m");
+        }
+
         if (link->network->dhcp_fallback_lease_lifetime > 0) {
                 r = sd_dhcp_client_set_fallback_lease_lifetime(link->dhcp_client, link->network->dhcp_fallback_lease_lifetime);
                 if (r < 0)
@@ -1701,6 +1707,42 @@ int config_parse_dhcp_ip_service_type(
         return 0;
 }
 
+int config_parse_dhcp_socket_priority(
+                const char *unit,
+                const char *filename,
+                unsigned line,
+                const char *section,
+                unsigned section_line,
+                const char *lvalue,
+                int ltype,
+                const char *rvalue,
+                void *data,
+                void *userdata) {
+
+        Network *network = ASSERT_PTR(data);
+        int a, r;
+
+        assert(lvalue);
+        assert(rvalue);
+
+        if (isempty(rvalue)) {
+                network->dhcp_socket_priority_set = false;
+                return 0;
+        }
+
+        r = safe_atoi(rvalue, &a);
+        if (r < 0) {
+                log_syntax(unit, LOG_WARNING, filename, line, r,
+                           "Failed to parse socket priority, ignoring: %s", rvalue);
+                return 0;
+        }
+
+        network->dhcp_socket_priority_set = true;
+        network->dhcp_socket_priority = a;
+
+        return 0;
+}
+
 int config_parse_dhcp_fallback_lease_lifetime(
                 const char *unit,
                 const char *filename,

src/network/networkd-dhcp4.h

@@ -29,6 +29,7 @@ int link_request_dhcp4_client(Link *link);
 CONFIG_PARSER_PROTOTYPE(config_parse_dhcp_client_identifier);
 CONFIG_PARSER_PROTOTYPE(config_parse_dhcp_max_attempts);
 CONFIG_PARSER_PROTOTYPE(config_parse_dhcp_ip_service_type);
+CONFIG_PARSER_PROTOTYPE(config_parse_dhcp_socket_priority);
 CONFIG_PARSER_PROTOTYPE(config_parse_dhcp_mud_url);
 CONFIG_PARSER_PROTOTYPE(config_parse_dhcp_fallback_lease_lifetime);
 CONFIG_PARSER_PROTOTYPE(config_parse_dhcp_label);

src/network/networkd-network-gperf.gperf

@@ -243,6 +243,7 @@ DHCPv4.SendDecline,                          config_parse_bool,
 DHCPv4.DenyList,                             config_parse_in_addr_prefixes,                            AF_INET,                       offsetof(Network, dhcp_deny_listed_ip)
 DHCPv4.AllowList,                            config_parse_in_addr_prefixes,                            AF_INET,                       offsetof(Network, dhcp_allow_listed_ip)
 DHCPv4.IPServiceType,                        config_parse_dhcp_ip_service_type,                        0,                             offsetof(Network, dhcp_ip_service_type)
+DHCPv4.SocketPriority,                       config_parse_dhcp_socket_priority,                        0,                             0
 DHCPv4.SendOption,                           config_parse_dhcp_send_option,                            AF_INET,                       offsetof(Network, dhcp_client_send_options)
 DHCPv4.SendVendorOption,                     config_parse_dhcp_send_option,                            0,                             offsetof(Network, dhcp_client_send_vendor_options)
 DHCPv4.RouteMTUBytes,                        config_parse_mtu,                                         AF_INET,                       offsetof(Network, dhcp_route_mtu)

src/network/networkd-network.h

@@ -130,6 +130,8 @@ struct Network {
         uint16_t dhcp_client_port;
         int dhcp_critical;
         int dhcp_ip_service_type;
+        int dhcp_socket_priority;
+        bool dhcp_socket_priority_set;
         bool dhcp_anonymize;
         bool dhcp_send_hostname;
         int dhcp_broadcast;