From: Dmitry V. Levin <ldv@strace.io>
Date: Fri, 14 Jul 2023 08:00:00 +0000 (+0000)
Subject: resolved: cleanup use of ERRNO_IS_DISCONNECT()
X-Git-Tag: v255-rc1~886^2~14
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=515669c46034f85f0337d100242c8b1336df39e3;p=thirdparty%2Fsystemd.git

resolved: cleanup use of ERRNO_IS_DISCONNECT()

Given that ERRNO_IS_DISCONNECT() also matches positive values,
make sure this macro is not called with arguments that do not have
errno semantics.

In this case the argument passed to ERRNO_IS_DISCONNECT() is the value
returned by dns_transaction_emit_tcp() and dns_transaction_emit_udp()
which are not expected to return any positive values, but let's be
consistent anyway and move the ERRNO_IS_DISCONNECT() invocation
to the branch where the return value is known to be negative.
---

diff --git a/src/resolve/resolved-dns-transaction.c b/src/resolve/resolved-dns-transaction.c
index 323786896bb..1ff452264aa 100644
--- a/src/resolve/resolved-dns-transaction.c
+++ b/src/resolve/resolved-dns-transaction.c
@@ -2079,7 +2079,7 @@ int dns_transaction_go(DnsTransaction *t) {
                 dns_transaction_complete(t, DNS_TRANSACTION_RR_TYPE_UNSUPPORTED);
                 return 0;
         }
-        if (t->scope->protocol == DNS_PROTOCOL_LLMNR && ERRNO_IS_DISCONNECT(r)) {
+        if (t->scope->protocol == DNS_PROTOCOL_LLMNR && r < 0 && ERRNO_IS_DISCONNECT(r)) {
                 /* On LLMNR, if we cannot connect to a host via TCP when doing reverse lookups. This means we cannot
                  * answer this request with this protocol. */
                 dns_transaction_complete(t, DNS_TRANSACTION_NOT_FOUND);