ring: Move generic code for ring layout setup to own function

Initialization of the ring->layout members is the same for RX and TX
rings. Instead of duplicating the code in setup_rx_ring_layout() and
setup_tx_ring_layout(), create a new function
setup_ring_layout_generic() which is called from the former two.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>

4 files changed, 28 insertions, 29 deletions

diff --git a/ring.c b/ring.c
index e42828e..26de18e 100644
--- a/ring.c
+++ b/ring.c
@@ -1,6 +1,7 @@
 /*
  * netsniff-ng - the packet sniffing beast
  * Copyright 2009, 2010 Daniel Borkmann.
+ * Copyright 2014, 2015 Tobias Klauser
  * Subject to the GPL, version 2.
  */
 
@@ -19,6 +20,26 @@
 #include "ring.h"
 #include "built_in.h"
 
+void setup_ring_layout_generic(int sock, struct ring *ring, size_t size,
+			       bool jumbo_support)
+{
+	fmemset(&ring->layout, 0, sizeof(ring->layout));
+
+	ring->layout.tp_block_size = (jumbo_support ?
+				      RUNTIME_PAGE_SIZE << 4 :
+				      RUNTIME_PAGE_SIZE << 2);
+
+	ring->layout.tp_frame_size = (jumbo_support ?
+				      TPACKET_ALIGNMENT << 12 :
+				      TPACKET_ALIGNMENT << 7);
+
+	ring->layout.tp_block_nr = size / ring->layout.tp_block_size;
+	ring->layout.tp_frame_nr = ring->layout.tp_block_size /
+				   ring->layout.tp_frame_size *
+				   ring->layout.tp_block_nr;
+
+}
+
 void mmap_ring_generic(int sock, struct ring *ring)
 {
 	ring->mm_space = mmap(NULL, ring->mm_len, PROT_READ | PROT_WRITE,
diff --git a/ring.h b/ring.h
index a195f74..0ac72bb 100644
--- a/ring.h
+++ b/ring.h
@@ -1,6 +1,7 @@
 /*
  * netsniff-ng - the packet sniffing beast
  * Copyright 2009, 2010 Daniel Borkmann.
+ * Copyright 2014, 2015 Tobias Klauser.
  * Subject to the GPL, version 2.
  */
 
@@ -196,6 +197,8 @@ static inline int get_sockopt_tpacket(int sock)
 	return val;
 }
 
+extern void setup_ring_layout_generic(int sock, struct ring *ring, size_t size,
+				      bool jumbo_support);
 extern void mmap_ring_generic(int sock, struct ring *ring);
 extern void alloc_ring_frames_generic(struct ring *ring, int num, size_t size);
 extern void bind_ring_generic(int sock, struct ring *ring, int ifindex, bool tx_only);
diff --git a/ring_rx.c b/ring_rx.c
index 11d1d08..1df7eb3 100644
--- a/ring_rx.c
+++ b/ring_rx.c
@@ -1,7 +1,7 @@
 /*
  * netsniff-ng - the packet sniffing beast
  * Copyright 2009, 2010 Daniel Borkmann.
- * Copyright 2014 Tobias Klauser.
+ * Copyright 2014, 2015 Tobias Klauser.
  * Subject to the GPL, version 2.
  */
 
@@ -142,20 +142,7 @@ void destroy_rx_ring(int sock, struct ring *ring)
 static void setup_rx_ring_layout(int sock, struct ring *ring, size_t size,
 				 bool jumbo_support, bool v3)
 {
-	fmemset(&ring->layout, 0, sizeof(ring->layout));
-
-	ring->layout.tp_block_size = (jumbo_support ?
-				      RUNTIME_PAGE_SIZE << 4 :
-				      RUNTIME_PAGE_SIZE << 2);
-
-	ring->layout.tp_frame_size = (jumbo_support ?
-				      TPACKET_ALIGNMENT << 12 :
-				      TPACKET_ALIGNMENT << 7);
-
-	ring->layout.tp_block_nr = size / ring->layout.tp_block_size;
-	ring->layout.tp_frame_nr = ring->layout.tp_block_size /
-				   ring->layout.tp_frame_size *
-				   ring->layout.tp_block_nr;
+	setup_ring_layout_generic(sock, ring, size, jumbo_support);
 
 	if (v3) {
 		setup_rx_ring_layout_v3(ring);
diff --git a/ring_tx.c b/ring_tx.c
index 27afe8b..aee1307 100644
--- a/ring_tx.c
+++ b/ring_tx.c
@@ -2,6 +2,7 @@
  * netsniff-ng - the packet sniffing beast
  * Copyright 2009, 2010 Daniel Borkmann.
  * Copyright 2009, 2010 Emmanuel Roullit.
+ * Copyright 2014, 2015 Tobias Klauser.
  * Subject to the GPL, version 2.
  */
 
@@ -48,20 +49,7 @@ void destroy_tx_ring(int sock, struct ring *ring)
 static void setup_tx_ring_layout(int sock, struct ring *ring, size_t size,
 				 bool jumbo_support)
 {
-	fmemset(&ring->layout, 0, sizeof(ring->layout));
-
-	ring->layout.tp_block_size = (jumbo_support ?
-				      RUNTIME_PAGE_SIZE << 4 :
-				      RUNTIME_PAGE_SIZE << 2);
-
-	ring->layout.tp_frame_size = (jumbo_support ?
-				      TPACKET_ALIGNMENT << 12 :
-				      TPACKET_ALIGNMENT << 7);
-
-	ring->layout.tp_block_nr = size / ring->layout.tp_block_size;
-	ring->layout.tp_frame_nr = ring->layout.tp_block_size /
-				   ring->layout.tp_frame_size *
-				   ring->layout.tp_block_nr;
+	setup_ring_layout_generic(sock, ring, size, jumbo_support);
 
 	set_sockopt_tpacket_v2(sock);