resolved: don't treat conn reset as packet loss

tcp reset / icmp port-unreachable are markedly different conditions than
packet loss. It doesn't make much sense to retry in this case. It's
actually not clear if there is any benefit at all retrying tcp
connections, which were presumably already retried as necessary by the
tcp stack.

diff --git a/src/resolve/resolved-dns-stream.c b/src/resolve/resolved-dns-stream.c
index 1a43d0bd4981b7608b12fe217e23661925810d45..8c1512006af30e5bfaeac4c1aab9645be6be5593 100644 (file)
--- a/src/resolve/resolved-dns-stream.c
+++ b/src/resolve/resolved-dns-stream.c
@@ -322,6 +322,12 @@ static int on_stream_io(sd_event_source *es, int fd, uint32_t revents, void *use
                         return dns_stream_complete(s, -r);
         }
 
+        if (revents & EPOLLERR) {
+                socklen_t errlen = sizeof(r);
+                if (getsockopt(s->fd, SOL_SOCKET, SO_ERROR, &r, &errlen) == 0)
+                        return dns_stream_complete(s, r);
+        }
+
         if ((revents & EPOLLOUT) &&
             s->write_packet &&
             s->n_written < sizeof(s->write_size) + s->write_packet->size) {

diff --git a/src/resolve/resolved-dns-transaction.c b/src/resolve/resolved-dns-transaction.c
index 20189f1cc7ebfc512cd08aff1ae7015f6304b8af..17a815cd44604367b072a939c4ca7f5da50010b9 100644 (file)
--- a/src/resolve/resolved-dns-transaction.c
+++ b/src/resolve/resolved-dns-transaction.c
@@ -633,7 +633,7 @@ static int on_stream_complete(DnsStream *s, int error) {
         if (ERRNO_IS_DISCONNECT(error) && s->protocol != DNS_PROTOCOL_LLMNR) {
                 log_debug_errno(error, "Connection failure for DNS TCP stream: %m");
 
-                if (s->transactions) {
+                if (error != ECONNRESET && s->transactions) {
                         DnsTransaction *t;
 
                         t = s->transactions;