From f50be1870d49465259d0c682680ec98dd0097be8 Mon Sep 17 00:00:00 2001
From: =?utf8?q?Zbigniew=20J=C4=99drzejewski-Szmek?= <zbyszek@in.waw.pl>
Date: Sat, 6 Apr 2024 19:01:56 +0200
Subject: [PATCH] networkd: report error if lease file cannot be loaded and
 ignore

On my system, networkd would report that interface ve-rawhide is "Failed"
without anything in the logs:
systemd-networkd[651095]: ve-rawhide: Trying to reconfigure the interface.
systemd-networkd[651095]: ve-rawhide: Gained IPv6LL
systemd-networkd[651095]: ve-rawhide: Link DOWN
systemd-networkd[651095]: ve-rawhide: Lost carrier
systemd-networkd[651095]: ve-rawhide: Configuring with /usr/lib/systemd/network/80-container-ve.network.
systemd-networkd[651095]: ve-rawhide: Link UP
systemd-networkd[651095]: ve-rawhide: Gained carrier
systemd-networkd[651095]: ve-rawhide: Failed

At debug level:
systemd-networkd[799993]: dhcp-server-lease/ve-rawhide:1:1: Missing object field 'Address'.

$ jq </var/lib/systemd/network/dhcp-server-lease/ve-rawhide
{
  "BootID": "5d86b34b98894322bfd4ae8443ce59b3",
  "Leases": [
    {
      "ClientId": [ ... ],
      "Address": [ 192, 168, 120, 179 ],
      "Hostname": "rawhide",
      "ExpirationUSec": 966046821158,
      "ExpirationRealtimeUSec": 1711203197266940
    }
  ]
}

I'm not sure why "Address" is missing, but anyway, in this case, we should ignore the
lease file rather than refusing to configure the interface. Also, warn at the point
where we know what the filename is.
---
 src/network/networkd-address.c     | 2 +-
 src/network/networkd-dhcp-server.c | 8 +++++++-
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/network/networkd-address.c b/src/network/networkd-address.c
index 542298c8c3..41d75bdf84 100644
--- a/src/network/networkd-address.c
+++ b/src/network/networkd-address.c
@@ -1496,7 +1496,7 @@ static int address_acquire(Link *link, const Address *address, union in_addr_uni
         assert(ret);
 
         r = address_acquire_from_dhcp_server_leases_file(link, address, ret);
-        if (r != -ENOENT)
+        if (!IN_SET(r, -ENOENT, -ENXIO, -EINVAL))
                 return r;
 
         r = address_pool_acquire(link->manager, address->family, address->prefixlen, &a);
diff --git a/src/network/networkd-dhcp-server.c b/src/network/networkd-dhcp-server.c
index 44b8aaa977..b1953545ed 100644
--- a/src/network/networkd-dhcp-server.c
+++ b/src/network/networkd-dhcp-server.c
@@ -197,8 +197,14 @@ int address_acquire_from_dhcp_server_leases_file(Link *link, const Address *addr
                         lease_file,
                         &a,
                         &prefixlen);
-        if (r < 0)
+        if (r == -ENOENT)
                 return r;
+        if (r < 0)
+                return log_warning_errno(r, "Failed to load lease file %s: %s",
+                                         lease_file,
+                                         r == -ENXIO ? "expected JSON content not found" :
+                                         r == -EINVAL ? "invalid JSON" :
+                                         STRERROR(r));
 
         if (prefixlen != address->prefixlen)
                 return -ENOENT;
-- 
2.25.1