net: TX_RING and packet mmap
New packet socket feature that makes packet socket more efficient for
transmission.
- It reduces number of system call through a PACKET_TX_RING mechanism,
based on PACKET_RX_RING (Circular buffer allocated in kernel space
which is mmapped from user space).
- It minimizes CPU copy using fragmented SKB (almost zero copy).
Signed-off-by: Johann Baudy <johann.baudy@gnu-log.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/if_packet.h b/include/linux/if_packet.h
index 18db066..5b2bade 100644
--- a/include/linux/if_packet.h
+++ b/include/linux/if_packet.h
@@ -46,6 +46,8 @@
#define PACKET_VERSION 10
#define PACKET_HDRLEN 11
#define PACKET_RESERVE 12
+#define PACKET_TX_RING 13
+#define PACKET_LOSS 14
struct tpacket_stats
{
@@ -63,14 +65,22 @@
__u16 tp_vlan_tci;
};
+/* Rx ring - header status */
+#define TP_STATUS_KERNEL 0x0
+#define TP_STATUS_USER 0x1
+#define TP_STATUS_COPY 0x2
+#define TP_STATUS_LOSING 0x4
+#define TP_STATUS_CSUMNOTREADY 0x8
+
+/* Tx ring - header status */
+#define TP_STATUS_AVAILABLE 0x0
+#define TP_STATUS_SEND_REQUEST 0x1
+#define TP_STATUS_SENDING 0x2
+#define TP_STATUS_WRONG_FORMAT 0x4
+
struct tpacket_hdr
{
unsigned long tp_status;
-#define TP_STATUS_KERNEL 0
-#define TP_STATUS_USER 1
-#define TP_STATUS_COPY 2
-#define TP_STATUS_LOSING 4
-#define TP_STATUS_CSUMNOTREADY 8
unsigned int tp_len;
unsigned int tp_snaplen;
unsigned short tp_mac;
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 1b5c3d2..aff494b 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -203,6 +203,9 @@
#ifdef CONFIG_HAS_DMA
dma_addr_t dma_maps[MAX_SKB_FRAGS + 1];
#endif
+ /* Intermediate layers must ensure that destructor_arg
+ * remains valid until skb destructor */
+ void * destructor_arg;
};
/* We divide dataref into two halves. The higher 16 bits hold references