tap: Re-read from tap in tap_handler_pasta() on buffer full

read() will return zero if we pass a zero length, which makes no
sense: instead, track explicitly that we exhausted the buffer, flush
packets to handlers and redo.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

1 files changed, 9 insertions, 2 deletions

diff --git a/tap.c b/tap.c
index f6de5f1..f8222a2 100644
--- a/tap.c
+++ b/tap.c
@@ -713,9 +713,12 @@ next:
  */
 static int tap_handler_pasta(struct ctx *c, const struct timespec *now)
 {
-	ssize_t n = 0, len;
+	ssize_t n, len;
 	int ret;
 
+redo:
+	n = 0;
+
 	pool_flush(pool_tap4);
 	pool_flush(pool_tap6);
 restart:
@@ -746,7 +749,8 @@ restart:
 			break;
 		}
 
-		n += len;
+		if ((n += len) == TAP_BUF_BYTES)
+			break;
 	}
 
 	if (len < 0 && errno == EINTR)
@@ -760,6 +764,9 @@ restart:
 	if (len > 0 || ret == EAGAIN)
 		return 0;
 
+	if (n == TAP_BUF_BYTES)
+		goto redo;
+
 	epoll_ctl(c->epollfd, EPOLL_CTL_DEL, c->fd_tap, NULL);
 	close(c->fd_tap);