dhcp: track last IPv4 address on start for renewal

Really only used by systemd because it doesn't have as good lease
handling, but it's also necessary if we switch DHCP clients mid-stream
(which we'll be doing later) since the new DHCP client won't
have a lease file for the current IP address, and thus has nowhere
to pull the current IP address from to request the same address
from the DHCP server.

8 files changed, 32 insertions, 23 deletions

diff --git a/src/devices/nm-device.c b/src/devices/nm-device.c
index 9eb25c96aa..9d8932f18a 100644
--- a/src/devices/nm-device.c
+++ b/src/devices/nm-device.c
@@ -2975,7 +2975,8 @@ dhcp4_start (NMDevice *self,
 	                                                nm_setting_ip_config_get_dhcp_hostname (s_ip4),
 	                                                nm_setting_ip4_config_get_dhcp_client_id (NM_SETTING_IP4_CONFIG (s_ip4)),
 	                                                priv->dhcp_timeout,
-	                                                priv->dhcp_anycast_address);
+	                                                priv->dhcp_anycast_address,
+	                                                NULL);
 
 	if (tmp)
 		g_byte_array_free (tmp, TRUE);
diff --git a/src/dhcp-manager/nm-dhcp-client.c b/src/dhcp-manager/nm-dhcp-client.c
index 69ed1120d6..0ffd573849 100644
--- a/src/dhcp-manager/nm-dhcp-client.c
+++ b/src/dhcp-manager/nm-dhcp-client.c
@@ -393,7 +393,8 @@ gboolean
 nm_dhcp_client_start_ip4 (NMDhcpClient *self,
                           const char *dhcp_client_id,
                           const char *dhcp_anycast_addr,
-                          const char *hostname)
+                          const char *hostname,
+                          const char *last_ip4_address)
 {
 	NMDhcpClientPrivate *priv;
 
@@ -412,7 +413,7 @@ nm_dhcp_client_start_ip4 (NMDhcpClient *self,
 	g_clear_pointer (&priv->hostname, g_free);
 	priv->hostname = g_strdup (hostname);
 
-	return NM_DHCP_CLIENT_GET_CLASS (self)->ip4_start (self, dhcp_anycast_addr);
+	return NM_DHCP_CLIENT_GET_CLASS (self)->ip4_start (self, dhcp_anycast_addr, last_ip4_address);
 }
 
 /* uuid_parse does not work for machine-id, so we use our own converter */
diff --git a/src/dhcp-manager/nm-dhcp-client.h b/src/dhcp-manager/nm-dhcp-client.h
index 5651c52025..d732aa05ef 100644
--- a/src/dhcp-manager/nm-dhcp-client.h
+++ b/src/dhcp-manager/nm-dhcp-client.h
@@ -64,7 +64,8 @@ typedef struct {
 	/* Methods */
 
 	gboolean (*ip4_start)     (NMDhcpClient *self,
-	                           const char *anycast_addr);
+	                           const char *anycast_addr,
+	                           const char *last_ip4_address);
 
 	gboolean (*ip6_start)     (NMDhcpClient *self,
 	                           const char *anycast_addr,
@@ -130,7 +131,8 @@ const char *nm_dhcp_client_get_hostname (NMDhcpClient *self);
 gboolean nm_dhcp_client_start_ip4 (NMDhcpClient *self,
                                    const char *dhcp_client_id,
                                    const char *dhcp_anycast_addr,
-                                   const char *hostname);
+                                   const char *hostname,
+                                   const char *last_ip4_address);
 
 gboolean nm_dhcp_client_start_ip6 (NMDhcpClient *self,
                                    const char *dhcp_anycast_addr,
diff --git a/src/dhcp-manager/nm-dhcp-dhclient.c b/src/dhcp-manager/nm-dhcp-dhclient.c
index c953c80d21..4cabb2257b 100644
--- a/src/dhcp-manager/nm-dhcp-dhclient.c
+++ b/src/dhcp-manager/nm-dhcp-dhclient.c
@@ -477,7 +477,7 @@ dhclient_start (NMDhcpClient *client,
 }
 
 static gboolean
-ip4_start (NMDhcpClient *client, const char *dhcp_anycast_addr)
+ip4_start (NMDhcpClient *client, const char *dhcp_anycast_addr, const char *last_ip4_address)
 {
 	NMDhcpDhclientPrivate *priv = NM_DHCP_DHCLIENT_GET_PRIVATE (client);
 	GBytes *client_id;
diff --git a/src/dhcp-manager/nm-dhcp-dhcpcd.c b/src/dhcp-manager/nm-dhcp-dhcpcd.c
index a39f953dbe..9aacba7667 100644
--- a/src/dhcp-manager/nm-dhcp-dhcpcd.c
+++ b/src/dhcp-manager/nm-dhcp-dhcpcd.c
@@ -73,7 +73,7 @@ dhcpcd_child_setup (gpointer user_data G_GNUC_UNUSED)
 }
 
 static gboolean
-ip4_start (NMDhcpClient *client, const char *dhcp_anycast_addr)
+ip4_start (NMDhcpClient *client, const char *dhcp_anycast_addr, const char *last_ip4_address)
 {
 	NMDhcpDhcpcdPrivate *priv = NM_DHCP_DHCPCD_GET_PRIVATE (client);
 	GPtrArray *argv = NULL;
diff --git a/src/dhcp-manager/nm-dhcp-manager.c b/src/dhcp-manager/nm-dhcp-manager.c
index dbc0684dbc..563b7ac91a 100644
--- a/src/dhcp-manager/nm-dhcp-manager.c
+++ b/src/dhcp-manager/nm-dhcp-manager.c
@@ -224,7 +224,8 @@ client_start (NMDhcpManager *self,
               const char *dhcp_anycast_addr,
               const char *hostname,
               gboolean info_only,
-              NMSettingIP6ConfigPrivacy privacy)
+              NMSettingIP6ConfigPrivacy privacy,
+              const char *last_ip4_address)
 {
 	NMDhcpManagerPrivate *priv;
 	NMDhcpClient *client;
@@ -265,7 +266,7 @@ client_start (NMDhcpManager *self,
 	if (ipv6)
 		success = nm_dhcp_client_start_ip6 (client, dhcp_anycast_addr, hostname, info_only, privacy);
 	else
-		success = nm_dhcp_client_start_ip4 (client, dhcp_client_id, dhcp_anycast_addr, hostname);
+		success = nm_dhcp_client_start_ip4 (client, dhcp_client_id, dhcp_anycast_addr, hostname, last_ip4_address);
 
 	if (!success) {
 		remove_client (self, client);
@@ -296,7 +297,8 @@ nm_dhcp_manager_start_ip4 (NMDhcpManager *self,
                            const char *dhcp_hostname,
                            const char *dhcp_client_id,
                            guint32 timeout,
-                           const char *dhcp_anycast_addr)
+                           const char *dhcp_anycast_addr,
+                           const char *last_ip_address)
 {
 	const char *hostname = NULL;
 
@@ -306,7 +308,7 @@ nm_dhcp_manager_start_ip4 (NMDhcpManager *self,
 		hostname = get_send_hostname (self, dhcp_hostname);
 	return client_start (self, iface, ifindex, hwaddr, uuid, priority, FALSE,
 	                     dhcp_client_id, timeout, dhcp_anycast_addr, hostname,
-	                     FALSE, 0);
+	                     FALSE, 0, last_ip_address);
 }
 
 /* Caller owns a reference to the NMDhcpClient on return */
@@ -332,7 +334,7 @@ nm_dhcp_manager_start_ip6 (NMDhcpManager *self,
 		hostname = get_send_hostname (self, dhcp_hostname);
 	return client_start (self, iface, ifindex, hwaddr, uuid, priority, TRUE,
 	                     NULL, timeout, dhcp_anycast_addr, hostname, info_only,
-	                     privacy);
+	                     privacy, NULL);
 }
 
 void
diff --git a/src/dhcp-manager/nm-dhcp-manager.h b/src/dhcp-manager/nm-dhcp-manager.h
index 0c3c3f2506..cf5519fbf8 100644
--- a/src/dhcp-manager/nm-dhcp-manager.h
+++ b/src/dhcp-manager/nm-dhcp-manager.h
@@ -61,7 +61,8 @@ NMDhcpClient * nm_dhcp_manager_start_ip4     (NMDhcpManager *manager,
                                               const char *dhcp_hostname,
                                               const char *dhcp_client_id,
                                               guint32 timeout,
-                                              const char *dhcp_anycast_addr);
+                                              const char *dhcp_anycast_addr,
+                                              const char *last_ip_address);
 
 NMDhcpClient * nm_dhcp_manager_start_ip6     (NMDhcpManager *manager,
                                               const char *iface,
diff --git a/src/dhcp-manager/nm-dhcp-systemd.c b/src/dhcp-manager/nm-dhcp-systemd.c
index 6d5204c8d9..3910339e5d 100644
--- a/src/dhcp-manager/nm-dhcp-systemd.c
+++ b/src/dhcp-manager/nm-dhcp-systemd.c
@@ -515,7 +515,7 @@ get_arp_type (const GByteArray *hwaddr)
 }
 
 static gboolean
-ip4_start (NMDhcpClient *client, const char *dhcp_anycast_addr)
+ip4_start (NMDhcpClient *client, const char *dhcp_anycast_addr, const char *last_ip4_address)
 {
 	NMDhcpSystemdPrivate *priv = NM_DHCP_SYSTEMD_GET_PRIVATE (client);
 	const char *iface = nm_dhcp_client_get_iface (client);
@@ -524,7 +524,7 @@ ip4_start (NMDhcpClient *client, const char *dhcp_anycast_addr)
 	GBytes *override_client_id;
 	const uint8_t *client_id = NULL;
 	size_t client_id_len = 0;
-	struct in_addr last_addr;
+	struct in_addr last_addr = { 0 };
 	const char *hostname;
 	int r, i;
 
@@ -578,14 +578,16 @@ ip4_start (NMDhcpClient *client, const char *dhcp_anycast_addr)
 
 	sd_dhcp_lease_load (priv->lease_file, &lease);
 
-	if (lease) {
-		r = sd_dhcp_lease_get_address (lease, &last_addr);
-		if (r == 0) {
-			r = sd_dhcp_client_set_request_address (priv->client4, &last_addr);
-			if (r < 0) {
-				nm_log_warn (LOGD_DHCP4, "(%s): failed to set last IPv4 address (%d)", iface, r);
-				goto error;
-			}
+	if (last_ip4_address)
+		inet_pton (AF_INET, last_ip4_address, &last_addr);
+	else if (lease)
+		sd_dhcp_lease_get_address (lease, &last_addr);
+
+	if (last_addr.s_addr) {
+		r = sd_dhcp_client_set_request_address (priv->client4, &last_addr);
+		if (r < 0) {
+			nm_log_warn (LOGD_DHCP4, "(%s): failed to set last IPv4 address (%d)", iface, r);
+			goto error;
 		}
 	}