socket: memory mapped netlink I/O support

Signed-off-by: Patrick McHardy <kaber@trash.net>

4 files changed, 74 insertions, 1 deletions

diff --git a/Make_global.am b/Make_global.am
index 3665b68..c538f09 100644
--- a/Make_global.am
+++ b/Make_global.am
@@ -21,4 +21,4 @@
 LIBVERSION=1:0:1
 
 AM_CPPFLAGS = ${regular_CPPFLAGS} -I${top_srcdir}/include
-AM_CFLAGS = ${regular_CFLAGS} ${GCC_FVISIBILITY_HIDDEN}
+AM_CFLAGS = ${regular_CFLAGS} ${GCC_FVISIBILITY_HIDDEN} -D_GNU_SOURCE
diff --git a/include/libmnl/libmnl.h b/include/libmnl/libmnl.h
index a647fd9..9b32630 100644
--- a/include/libmnl/libmnl.h
+++ b/include/libmnl/libmnl.h
@@ -26,8 +26,16 @@ extern "C" {
 
 struct mnl_socket;
 
+enum mnl_ring_types {
+	MNL_RING_RX,
+	MNL_RING_TX,
+};
+
 extern struct mnl_socket *mnl_socket_open(int type);
 extern int mnl_socket_bind(struct mnl_socket *nl, unsigned int groups, pid_t pid);
+extern int mnl_socket_set_ring(struct mnl_socket *nl, unsigned int rx_size, unsigned int tx_size);
+extern struct nl_mmap_hdr *mnl_socket_get_frame(struct mnl_socket *nl, enum mnl_ring_types type);
+extern void mnl_socket_advance_ring(struct mnl_socket *nl, enum mnl_ring_types type);
 extern int mnl_socket_close(struct mnl_socket *nl);
 extern int mnl_socket_get_fd(const struct mnl_socket *nl);
 extern unsigned int mnl_socket_get_portid(const struct mnl_socket *nl);
diff --git a/src/libmnl.map b/src/libmnl.map
index dbc332e..8216b19 100644
--- a/src/libmnl.map
+++ b/src/libmnl.map
@@ -57,6 +57,9 @@ global:
   mnl_nlmsg_batch_head;
   mnl_nlmsg_batch_is_empty;
   mnl_socket_bind;
+  mnl_socket_set_ring;
+  mnl_socket_get_frame;
+  mnl_socket_advance_ring;
   mnl_socket_close;
   mnl_socket_get_fd;
   mnl_socket_get_portid;
diff --git a/src/socket.c b/src/socket.c
index 6d54563..d6f5604 100644
--- a/src/socket.c
+++ b/src/socket.c
@@ -10,6 +10,7 @@
 #include <libmnl/libmnl.h>
 #include <sys/types.h>
 #include <sys/socket.h>
+#include <sys/mman.h>
 #include <stdlib.h>
 #include <unistd.h>
 #include <time.h>
@@ -66,9 +67,18 @@
  * code tree.
  */
 
+struct mnl_ring {
+	unsigned int		head;
+	void			*ring;
+};
+
 struct mnl_socket {
 	int 			fd;
 	struct sockaddr_nl	addr;
+	unsigned int		frame_size;
+	unsigned int		frame_nr;
+	struct mnl_ring		rx_ring;
+	struct mnl_ring		tx_ring;
 };
 
 /**
@@ -168,6 +178,58 @@ int mnl_socket_bind(struct mnl_socket *nl, unsigned int groups, pid_t pid)
 }
 EXPORT_SYMBOL(mnl_socket_bind);
 
+int mnl_socket_set_ring(struct mnl_socket *nl, unsigned int rx_size,
+			unsigned int tx_size)
+{
+	struct nl_mmap_req req = {
+		.nm_block_size		= 16 * 4096,
+		.nm_block_nr		= 64,
+		.nm_frame_size		= 16384,
+		.nm_frame_nr		= 256,
+	};
+	unsigned int size;
+	void *ring;
+
+	if (mnl_socket_setsockopt(nl, NETLINK_RX_RING, &req, sizeof(req)) < 0)
+		return -1;
+	if (mnl_socket_setsockopt(nl, NETLINK_TX_RING, &req, sizeof(req)) < 0)
+		return -1;
+
+	size = req.nm_block_nr * req.nm_block_size;
+	ring = mmap(NULL, 2 * size, PROT_READ | PROT_WRITE, MAP_SHARED, nl->fd, 0);
+	if ((long)ring == -1L)
+		return -1;
+
+	nl->frame_size   = req.nm_frame_size;
+	nl->frame_nr     = req.nm_frame_nr - 1;
+	nl->rx_ring.ring = ring;
+	nl->rx_ring.head = 0;
+	nl->tx_ring.ring = ring + size;
+	nl->tx_ring.head = 0;
+
+	return 0;
+}
+EXPORT_SYMBOL(mnl_socket_set_ring);
+
+struct nl_mmap_hdr *mnl_socket_get_frame(struct mnl_socket *nl,
+					 enum mnl_ring_types type)
+{
+	struct mnl_ring *ring;
+
+	ring = type == MNL_RING_RX ? &nl->rx_ring : &nl->tx_ring;
+	return ring->ring + ring->head * nl->frame_size;
+}
+EXPORT_SYMBOL(mnl_socket_get_frame);
+
+void mnl_socket_advance_ring(struct mnl_socket *nl, enum mnl_ring_types type)
+{
+	struct mnl_ring *ring;
+
+	ring = type == MNL_RING_RX ? &nl->rx_ring : &nl->tx_ring;
+	ring->head = ring->head != nl->frame_nr ? ring->head + 1 : 0;
+}
+EXPORT_SYMBOL(mnl_socket_advance_ring);
+
 /**
  * mnl_socket_sendto - send a netlink message of a certain size
  * \param nl netlink socket obtained via mnl_socket_open()