passt: Introduce packet batching mechanism

Receive packets in batches from AF_UNIX, check if they can be sent
with a single syscall, and batch them up with sendmmsg() in case.

A bit rudimentary, currently only implemented for UDP, but it seems
to work.

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

1 files changed, 14 insertions, 0 deletions

diff --git a/passt.h b/passt.h
index 9844858..87d91e5 100644
--- a/passt.h
+++ b/passt.h
@@ -1,5 +1,19 @@
 #define UNIX_SOCK_PATH	"/tmp/passt.socket"
 
+/**
+ * struct tap_msg - Generic message descriptor for arrays of messages
+ * @start:	Pointer to message start
+ * @l4_start:	Pointer to L4 header
+ * @len:	Message length, with L2 headers
+ * @l4_len:	Message length, with L4 headers
+ */
+struct tap_msg {
+	char *start;
+	char *l4h;
+	size_t len;
+	size_t l4_len;
+};
+
 #include "icmp.h"
 #include "tcp.h"