netsniff-ng trafgen: check return value of pull_and_flush_ring

Let us check the return value when the timer triggers a TX flush
request to the kernel. However, ignore the case of BADFS and NOBUFS.
The socket could already have been closed before the timer triggers
in the first case, and in the second, we just let the next timer
continue processing if currently the buffer space is exhausted.

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>

2 files changed, 24 insertions, 2 deletions

diff --git a/netsniff-ng.c b/netsniff-ng.c
index 94fb313..6f7c4c2 100644
--- a/netsniff-ng.c
+++ b/netsniff-ng.c
@@ -115,8 +115,19 @@ static void signal_handler(int number)
 
 static void timer_elapsed(int unused)
 {
+	int ret;
+
 	set_itimer_interval_value(&itimer, 0, interval);
-	pull_and_flush_tx_ring(tx_sock);
+
+	ret = pull_and_flush_tx_ring(tx_sock);
+	if (unlikely(ret < 0)) {
+		/* We could hit EBADF if the socket has been closed before
+		 * the timer was triggered.
+		 */
+		if (errno != EBADF && errno != ENOBUFS)
+			panic("Flushing TX_RING failed: %s!\n", strerror(errno));
+	}
+
 	setitimer(ITIMER_REAL, &itimer, NULL);
 }
 
diff --git a/trafgen.c b/trafgen.c
index 03c12c5..02aa2df 100644
--- a/trafgen.c
+++ b/trafgen.c
@@ -127,8 +127,19 @@ static void signal_handler(int number)
 
 static void timer_elapsed(int number)
 {
+	int ret;
+
 	set_itimer_interval_value(&itimer, 0, interval);
-	pull_and_flush_tx_ring(sock);
+
+	ret = pull_and_flush_tx_ring(sock);
+	if (unlikely(ret < 0)) {
+		/* We could hit EBADF if the socket has been closed before
+		 * the timer was triggered.
+		 */
+		if (errno != EBADF && errno != ENOBUFS)
+			panic("Flushing TX_RING failed: %s!\n", strerror(errno));
+	}
+
 	setitimer(ITIMER_REAL, &itimer, NULL); 
 }