networkd-dhcp6: generalize DHCPv6 client (re)starting

dhcp6_request_address() was merely a function to switch the DHCPv6 client from "stateless" mode to "stateful" mode. It was also a one-way switch. Also, to (re)start the client, we would need to repeat separate function calls.

In this patch, dhcp6_request_address() is made a general starter/manager of the DHCPv6 client. It now takes an extra parameter so we will be specifying which mode the DHCPv6 client should be started in. Also it will keep track of the current mode and compare with the newly requested mode, and only restart the client in case there is a difference between them.

This also makes sure that the DHCPv6 client will be (re)started accordingly as per the Router Advertisement flags.

1 files changed, 18 insertions, 13 deletions

diff --git a/src/network/networkd-dhcp6.c b/src/network/networkd-dhcp6.c
index a44c9ea71d..50721b1c74 100644
--- a/src/network/networkd-dhcp6.c
+++ b/src/network/networkd-dhcp6.c
@@ -164,19 +164,13 @@ static void dhcp6_handler(sd_dhcp6_client *client, int event, void *userdata) {
         link_check_ready(link);
 }
 
-int dhcp6_request_address(Link *link) {
+int dhcp6_request_address(Link *link, int ir) {
         int r, inf_req;
         bool running;
 
         assert(link);
         assert(link->dhcp6_client);
-
-        r = sd_dhcp6_client_get_information_request(link->dhcp6_client, &inf_req);
-        if (r < 0)
-                return r;
-
-        if (!inf_req)
-                return 0;
+        assert(in_addr_is_link_local(AF_INET6, (const union in_addr_union*)&link->ipv6ll_address) > 0);
 
         r = sd_dhcp6_client_is_running(link->dhcp6_client);
         if (r < 0)
@@ -185,12 +179,27 @@ int dhcp6_request_address(Link *link) {
                 running = !!r;
 
         if (running) {
+                r = sd_dhcp6_client_get_information_request(link->dhcp6_client, &inf_req);
+                if (r < 0)
+                        return r;
+
+                if (inf_req == ir)
+                        return 0;
+
                 r = sd_dhcp6_client_stop(link->dhcp6_client);
                 if (r < 0)
                         return r;
+        } else {
+                r = sd_dhcp6_client_set_local_address(link->dhcp6_client, &link->ipv6ll_address);
+                if (r < 0)
+                        return r;
         }
 
-        r = sd_dhcp6_client_set_information_request(link->dhcp6_client, false);
+        r = sd_dhcp6_client_set_information_request(link->dhcp6_client, ir);
+        if (r < 0)
+                return r;
+
+        r = sd_dhcp6_client_start(link->dhcp6_client);
         if (r < 0)
                 return r;
 
@@ -215,10 +224,6 @@ int dhcp6_configure(Link *link) {
         if (r < 0)
                 goto error;
 
-        r = sd_dhcp6_client_set_information_request(client, true);
-        if (r < 0)
-                goto error;
-
         r = sd_dhcp6_client_set_mac(client,
                                     (const uint8_t *) &link->mac,
                                     sizeof (link->mac), ARPHRD_ETHER);