platform: retry link change on RESULT_FAILED_RESYNC

Sometimes the buffer space of the netlink socket runs out and we lose
the response to our link change:

  <info>  [1670321010.2952] platform-linux: netlink[rtnl]: read: too many netlink events. Need to resynchronize platform cache
  <warn>  [1670321010.3467] platform-linux: do-change-link[2]: failure changing link: internal failure 3

With 3 above being WAIT_FOR_NL_RESPONSE_RESULT_FAILED_RESYNC.

Let's try harder.

https://bugzilla.redhat.com/show_bug.cgi?id=2154350
(cherry picked from commit b8738002edd34c975b387d961458d2864c93c3ba)

1 files changed, 24 insertions, 11 deletions

diff --git a/src/libnm-platform/nm-linux-platform.c b/src/libnm-platform/nm-linux-platform.c
index 10c94933eb..b798d12d2a 100644
--- a/src/libnm-platform/nm-linux-platform.c
+++ b/src/libnm-platform/nm-linux-platform.c
@@ -7896,19 +7896,25 @@ do_change_link(NMPlatform           *platform,
     WaitForNlResponseResult     seq_result = WAIT_FOR_NL_RESPONSE_RESULT_UNKNOWN;
     gs_free char               *errmsg     = NULL;
     char                        s_buf[256];
-    int                         result          = 0;
-    NMLogLevel                  log_level       = LOGL_DEBUG;
-    const char                 *log_detail      = "";
+    int                         result;
+    NMLogLevel                  log_level;
+    const char                 *log_detail;
     gs_free char               *log_detail_free = NULL;
     const NMPObject            *obj_cache;
 
     if (!nm_platform_netns_push(platform, &netns)) {
         log_level  = LOGL_ERR;
         log_detail = ", failure to change network namespace";
+        result     = -NME_UNSPEC;
         goto out;
     }
 
 retry:
+    result     = -NME_UNSPEC;
+    log_level  = LOGL_WARN;
+    log_detail = "";
+    nm_clear_g_free(&log_detail_free);
+
     nle = _netlink_send_nlmsg_rtnl(platform, nlmsg, &seq_result, &errmsg);
     if (nle < 0) {
         log_level = LOGL_ERR;
@@ -7926,13 +7932,19 @@ retry:
 
     nm_assert(seq_result);
 
-    if (NM_IN_SET(seq_result, -EOPNOTSUPP) && nlmsg_hdr(nlmsg)->nlmsg_type == RTM_NEWLINK) {
+    if (NM_IN_SET(seq_result, WAIT_FOR_NL_RESPONSE_RESULT_RESPONSE_OK, -EEXIST, -EADDRINUSE)) {
+        log_level = LOGL_DEBUG;
+        result    = 0;
+    } else if (NM_IN_SET(seq_result, -EOPNOTSUPP) && nlmsg_hdr(nlmsg)->nlmsg_type == RTM_NEWLINK) {
         nlmsg_hdr(nlmsg)->nlmsg_type = RTM_SETLINK;
-        goto retry;
-    }
 
-    if (NM_IN_SET(seq_result, WAIT_FOR_NL_RESPONSE_RESULT_RESPONSE_OK, -EEXIST, -EADDRINUSE)) {
-        /* */
+        log_level  = LOGL_INFO;
+        log_detail = ", will try SETLINK instead of NEWLINK";
+        result     = -EAGAIN;
+    } else if (seq_result == WAIT_FOR_NL_RESPONSE_RESULT_FAILED_RESYNC) {
+        log_level  = LOGL_INFO;
+        log_detail = ", due to lost synchronization";
+        result     = -EAGAIN;
     } else if (NM_IN_SET(seq_result, -ESRCH, -ENOENT)) {
         log_detail = ", firmware not found";
         result     = -NME_PL_NO_FIRMWARE;
@@ -7956,9 +7968,6 @@ retry:
     } else if (seq_result == -EAFNOSUPPORT) {
         log_level = LOGL_DEBUG;
         result    = -NME_PL_OPNOTSUPP;
-    } else {
-        log_level = LOGL_WARN;
-        result    = -NME_UNSPEC;
     }
 
 out:
@@ -7967,6 +7976,10 @@ out:
            ifindex,
            wait_for_nl_response_to_string(seq_result, errmsg, s_buf, sizeof(s_buf)),
            log_detail);
+
+    if (result == -EAGAIN)
+        goto retry;
+
     return result;
 }