trafgen: take advantage of PACKET_QDISC_BYPASS sock option

Since Linux 3.14, the kernel supports a socket option PACKET_QDISC_BYPASS,
which trafgen enables by default. That allow us to bypass the kernels
normal qdisc (traffic control) layer.

An option -q, --qdisc-path is added to allow enabling the qdisc path
explicity, useful for testing purposes.

This will be avail in kernels >= 3.14 via
 commit d346a3fae3 (packet: introduce PACKET_QDISC_BYPASS socket option).

Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/built_in.h b/built_in.h
index 6f6625e..20d7317 100644
--- a/built_in.h
+++ b/built_in.h
@@ -370,6 +370,10 @@ static inline u64 cpu_to_le64(u64 val)
 # define TP_STATUS_TS_RAW_HARDWARE	(1 << 31)
 #endif
 
+#ifndef PACKET_QDISC_BYPASS
+# define PACKET_QDISC_BYPASS 20
+#endif
+
 #ifndef POLLRDNORM
 # define POLLRDNORM			0x0040
 #endif