trafgen: l2: Add Ethernet protocol header generation

Add trafgen_l2.c module for generating L2 related headers.

Add Ethernet header generating. By default source MAC address
is used from the specified output device.

Signed-off-by: Vadim Kochan <vadim4j@gmail.com>
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>

4 files changed, 49 insertions, 1 deletions

diff --git a/trafgen/Makefile b/trafgen/Makefile
index 2ea684f..1c95118 100644
--- a/trafgen/Makefile
+++ b/trafgen/Makefile
@@ -20,6 +20,7 @@ trafgen-objs =	xmalloc.o \
 		sysctl.o \
 		cpp.o \
 		trafgen_proto.o \
+		trafgen_l2.o \
 		trafgen_lexer.yy.o \
 		trafgen_parser.tab.o \
 		trafgen.o
diff --git a/trafgen_l2.c b/trafgen_l2.c
new file mode 100644
index 0000000..1082049
--- /dev/null
+++ b/trafgen_l2.c
@@ -0,0 +1,32 @@
+/*
+ * netsniff-ng - the packet sniffing beast
+ * Subject to the GPL, version 2.
+ */
+
+#include "built_in.h"
+#include "trafgen_l2.h"
+#include "trafgen_proto.h"
+
+struct proto_field eth_fields[] = {
+	{ .id = ETH_DST_ADDR, .len = 6, },
+	{ .id = ETH_SRC_ADDR, .len = 6, .offset = 6 },
+	{ .id = ETH_PROTO_ID, .len = 2, .offset = 12 },
+};
+
+static void eth_header_init(struct proto_hdr *hdr)
+{
+	proto_header_fields_add(hdr, eth_fields, array_size(eth_fields));
+
+	proto_field_set_default_dev_mac(hdr, ETH_SRC_ADDR);
+}
+
+static struct proto_hdr eth_hdr = {
+	.id		= PROTO_ETH,
+	.layer		= PROTO_L2,
+	.header_init	= eth_header_init,
+};
+
+void protos_l2_init(void)
+{
+	proto_header_register(&eth_hdr);
+}
diff --git a/trafgen_l2.h b/trafgen_l2.h
new file mode 100644
index 0000000..e0d9702
--- /dev/null
+++ b/trafgen_l2.h
@@ -0,0 +1,12 @@
+#ifndef TRAFGEN_L2_H
+#define TRAFGEN_L2_H
+
+enum eth_field {
+	ETH_DST_ADDR,
+	ETH_SRC_ADDR,
+	ETH_PROTO_ID,
+};
+
+extern void protos_l2_init(void);
+
+#endif /* TRAFGEN_L2_H */
diff --git a/trafgen_proto.c b/trafgen_proto.c
index cf2541f..4976e54 100644
--- a/trafgen_proto.c
+++ b/trafgen_proto.c
@@ -10,6 +10,7 @@
 #include "dev.h"
 #include "xmalloc.h"
 #include "trafgen_conf.h"
+#include "trafgen_l2.h"
 #include "trafgen_proto.h"
 
 #define field_shift_and_mask(f, v) (((v) << (f)->shift) & \
@@ -305,7 +306,7 @@ static void __proto_field_set_dev_mac(struct proto_hdr *hdr, uint32_t fid,
 
 	ret = device_hw_address(hdr->ctx->dev, mac, sizeof(mac));
 	if (ret < 0)
-		panic("Could not get device hw adress\n");
+		panic("Could not get device hw address\n");
 
 	__proto_field_set_bytes(hdr, fid, mac, is_default, false);
 }
@@ -326,6 +327,8 @@ void protos_init(const char *dev)
 
 	ctx.dev = dev;
 
+	protos_l2_init();
+
 	for (p = registered; p; p = p->next)
 		p->ctx = &ctx;
 }