dumpcap: do all packet counting in capture_loop_wrote_one_packet().

We need to update global_ld.inpkts_to_sync_pipe as soon as we've written
a packet to the current capture file.  If we're writing to multiple
files, then, if we delay counting until after we switch to another file,
the packet-count message we send to the parent before switching won't
include the packet, and the first packet-count message we send to the
parent *after* switching *will* include the packet, which could mean the
parent will try to read more packets than there are in the new file, in
which case it'll get an EOF and, at least in the case of TShark, treat
that as an error and stop capturing.

This should fix issue #17654.

While we're at it, don't send a "we have no packets" packet-count
message even for the packet-count message we send just before switching
files.

1 files changed, 7 insertions, 6 deletions

diff --git a/dumpcap.c b/dumpcap.c
index 43d85b63f8..80f66a9d1b 100644
--- a/dumpcap.c
+++ b/dumpcap.c
@@ -3760,9 +3760,11 @@ do_file_switch_or_stop(capture_options *capture_opts)
                 global_ld.next_interval_time = get_next_time_interval(global_ld.interval_s);
             }
             fflush(global_ld.pdh);
-            if (!quiet)
-                report_packet_count(global_ld.inpkts_to_sync_pipe);
-            global_ld.inpkts_to_sync_pipe = 0;
+            if (global_ld.inpkts_to_sync_pipe) {
+                if (!quiet)
+                    report_packet_count(global_ld.inpkts_to_sync_pipe);
+                global_ld.inpkts_to_sync_pipe = 0;
+            }
             report_new_capture_file(capture_opts->save_file);
         } else {
             /* File switch failed: stop here */
@@ -4081,8 +4083,6 @@ capture_loop_start(capture_options *capture_opts, gboolean *stats_known, struct
 #endif
 
         if (inpkts > 0) {
-            global_ld.inpkts_to_sync_pipe += inpkts;
-
             if (capture_opts->output_to_pipe) {
                 fflush(global_ld.pdh);
             }
@@ -4161,7 +4161,6 @@ capture_loop_start(capture_options *capture_opts, gboolean *stats_known, struct
             if (!dequeued) {
                 break;
             }
-            global_ld.inpkts_to_sync_pipe += 1;
             if (capture_opts->output_to_pipe) {
                 fflush(global_ld.pdh);
             }
@@ -4475,6 +4474,8 @@ static void
 capture_loop_wrote_one_packet(capture_src *pcap_src) {
     global_ld.packets_captured++;
     global_ld.packets_written++;
+    global_ld.inpkts_to_sync_pipe++;
+
     if (!use_threads) {
         pcap_src->received++;
     }