From: Yu Watanabe <watanabe.yu+github@gmail.com>
Date: Thu, 16 Jul 2020 01:31:49 +0000 (+0900)
Subject: network: dhcp4: fix another race with SendDecline=yes
X-Git-Tag: v246-rc2~59^2~1
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=153cf041399fe76c80c2c96d98ec5489a83f44ed;p=thirdparty%2Fsystemd.git

network: dhcp4: fix another race with SendDecline=yes

If the SD_IPV4ACD_EVENT_BIND event happens before all routes are
assigned, then the link stuck in configuring state.
---

diff --git a/src/network/networkd-dhcp4.c b/src/network/networkd-dhcp4.c
index fd26be18fdb..f732f385671 100644
--- a/src/network/networkd-dhcp4.c
+++ b/src/network/networkd-dhcp4.c
@@ -52,12 +52,16 @@ static void dhcp4_release_old_lease(Link *link) {
 }
 
 static void dhcp4_check_ready(Link *link) {
-        if (link->dhcp4_messages == 0) {
-                link->dhcp4_configured = true;
-                /* New address and routes are configured now. Let's release old lease. */
-                dhcp4_release_old_lease(link);
-                link_check_ready(link);
-        }
+        if (link->network->dhcp_send_decline && !link->dhcp4_address_bind)
+                return;
+
+        if (link->dhcp4_messages > 0)
+                return;
+
+        link->dhcp4_configured = true;
+        /* New address and routes are configured now. Let's release old lease. */
+        dhcp4_release_old_lease(link);
+        link_check_ready(link);
 }
 
 static int dhcp4_route_handler(sd_netlink *rtnl, sd_netlink_message *m, Link *link) {
@@ -86,20 +90,18 @@ static int dhcp4_route_handler(sd_netlink *rtnl, sd_netlink_message *m, Link *li
                 return 1;
         }
 
-        if (link->dhcp4_messages == 0) {
-                if (link->dhcp4_route_failed) {
-                        link->dhcp4_route_failed = false;
-                        link->dhcp4_route_retrying = true;
+        if (link->dhcp4_messages == 0 && link->dhcp4_route_failed) {
+                link->dhcp4_route_failed = false;
+                link->dhcp4_route_retrying = true;
 
-                        r = dhcp4_remove_all(link);
-                        if (r < 0)
-                                link_enter_failed(link);
-                        return 1;
-                }
-                if (!link->network->dhcp_send_decline)
-                        dhcp4_check_ready(link);
+                r = dhcp4_remove_all(link);
+                if (r < 0)
+                        link_enter_failed(link);
+                return 1;
         }
 
+        dhcp4_check_ready(link);
+
         return 1;
 }
 
@@ -836,6 +838,7 @@ static void dhcp_address_on_acd(sd_ipv4acd *acd, int event, void *userdata) {
                         (void) in_addr_to_string(AF_INET, &address, &pretty);
                         log_link_debug(link, "Successfully claimed DHCP4 address %s", strna(pretty));
                 }
+                link->dhcp4_address_bind = true;
                 dhcp4_check_ready(link);
                 break;
 
@@ -886,6 +889,44 @@ static int configure_dhcpv4_duplicate_address_detection(Link *link) {
         return 0;
 }
 
+static int dhcp4_start_acd(Link *link) {
+        union in_addr_union addr;
+        int r;
+
+        if (!link->network->dhcp_send_decline)
+                return 0;
+
+        if (!link->dhcp_lease)
+                return 0;
+
+        link->dhcp4_address_bind = false;
+
+        r = sd_dhcp_lease_get_address(link->dhcp_lease, &addr.in);
+        if (r < 0)
+                return r;
+
+        r = sd_ipv4acd_set_address(link->network->dhcp_acd, &addr.in);
+        if (r < 0)
+                return r;
+
+        r = sd_ipv4acd_set_callback(link->network->dhcp_acd, dhcp_address_on_acd, link);
+        if (r < 0)
+                return r;
+
+        if (DEBUG_LOGGING) {
+                _cleanup_free_ char *pretty = NULL;
+
+                (void) in_addr_to_string(AF_INET, &addr, &pretty);
+                log_link_debug(link, "Starting IPv4ACD client. Probing DHCPv4 address %s", strna(pretty));
+        }
+
+        r = sd_ipv4acd_start(link->network->dhcp_acd, true);
+        if (r < 0)
+                return r;
+
+        return 1;
+}
+
 static int dhcp4_address_handler(sd_netlink *rtnl, sd_netlink_message *m, Link *link) {
         int r;
 
@@ -915,31 +956,14 @@ static int dhcp4_address_handler(sd_netlink *rtnl, sd_netlink_message *m, Link *
                 return 1;
         }
 
-        if (link->network->dhcp_send_decline) {
-                union in_addr_union addr;
-
-                (void) sd_dhcp_lease_get_address(link->dhcp_lease, &addr.in);
-
-                r = sd_ipv4acd_set_address(link->network->dhcp_acd, &addr.in);
-                if (r < 0)
-                        return r;
-
-                r = sd_ipv4acd_set_callback(link->network->dhcp_acd, dhcp_address_on_acd, link);
-                if (r < 0)
-                        return r;
-
-                if (DEBUG_LOGGING) {
-                        _cleanup_free_ char *pretty = NULL;
-
-                        (void) in_addr_to_string(AF_INET, &addr, &pretty);
-                        log_link_debug(link, "Starting IPv4ACD client. Probing DHCPv4 address %s", strna(pretty));
-                }
+        r = dhcp4_start_acd(link);
+        if (r < 0) {
+                log_link_error_errno(link, r, "Failed to start IPv4ACD for DHCP4 adddress: %m");
+                link_enter_failed(link);
+                return 1;
+        }
 
-                r = sd_ipv4acd_start(link->network->dhcp_acd, true);
-                if (r < 0)
-                        log_link_warning_errno(link, r, "Failed to start IPv4ACD client, ignoring: %m");
-        } else
-                dhcp4_check_ready(link);
+        dhcp4_check_ready(link);
 
         return 1;
 }
diff --git a/src/network/networkd-link.h b/src/network/networkd-link.h
index 7b39dd91ae5..fb12301fe6e 100644
--- a/src/network/networkd-link.h
+++ b/src/network/networkd-link.h
@@ -108,6 +108,7 @@ typedef struct Link {
         bool dhcp4_route_failed:1;
         bool dhcp4_route_retrying:1;
         bool dhcp4_configured:1;
+        bool dhcp4_address_bind:1;
         bool dhcp6_address_configured:1;
         bool dhcp6_route_configured:1;
         bool dhcp6_pd_address_configured:1;