1 files changed, 130 insertions, 0 deletions
diff --git a/ring_rx.c b/ring_rx.c
new file mode 100644
index 0000000..c4c6a38
--- /dev/null
+++ b/ring_rx.c
@@ -0,0 +1,130 @@
+/*
+ * netsniff-ng - the packet sniffing beast
+ * Copyright 2009, 2010 Daniel Borkmann.
+ * Subject to the GPL, version 2.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/mman.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <arpa/inet.h>
+#include <linux/if_ether.h>
+
+#include "xmalloc.h"
+#include "die.h"
+#include "ring_rx.h"
+#include "built_in.h"
+
+void destroy_rx_ring(int sock, struct ring *ring)
+{
+	fmemset(&ring->layout, 0, sizeof(ring->layout));
+	setsockopt(sock, SOL_PACKET, PACKET_RX_RING, &ring->layout,
+		   sizeof(ring->layout));
+
+	munmap(ring->mm_space, ring->mm_len);
+	ring->mm_len = 0;
+
+	xfree(ring->frames);
+}
+
+void setup_rx_ring_layout(int sock, struct ring *ring, unsigned int size,
+			  int jumbo_support)
+{
+	fmemset(&ring->layout, 0, sizeof(ring->layout));
+
+	ring->layout.tp_block_size = (jumbo_support ?
+				      getpagesize() << 4 :
+				      getpagesize() << 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;
+
+	bug_on(ring->layout.tp_block_size < ring->layout.tp_frame_size);
+	bug_on((ring->layout.tp_block_size % ring->layout.tp_frame_size) != 0);
+	bug_on((ring->layout.tp_block_size % getpagesize()) != 0);
+}
+
+void create_rx_ring(int sock, struct ring *ring, int verbose)
+{
+	int ret;
+
+	set_sockopt_tpacket(sock);
+retry:
+	ret = setsockopt(sock, SOL_PACKET, PACKET_RX_RING, &ring->layout,
+			 sizeof(ring->layout));
+	if (errno == ENOMEM && ring->layout.tp_block_nr > 1) {
+		ring->layout.tp_block_nr >>= 1;
+		ring->layout.tp_frame_nr = ring->layout.tp_block_size / 
+					   ring->layout.tp_frame_size * 
+					   ring->layout.tp_block_nr;
+		goto retry;
+	}
+
+	if (ret < 0)
+		panic("Cannot allocate RX_RING!\n");
+
+	ring->mm_len = ring->layout.tp_block_size * ring->layout.tp_block_nr;
+
+	if (verbose) {
+		printf("RX: %.2Lf MiB, %u Frames, each %u Byte allocated\n",
+		       (long double) ring->mm_len / (1 << 20),
+		       ring->layout.tp_frame_nr, ring->layout.tp_frame_size);
+	}
+}
+
+void mmap_rx_ring(int sock, struct ring *ring)
+{
+	ring->mm_space = mmap(0, ring->mm_len, PROT_READ | PROT_WRITE,
+			      MAP_SHARED | MAP_LOCKED | MAP_POPULATE, sock, 0);
+	if (ring->mm_space == MAP_FAILED) {
+		destroy_rx_ring(sock, ring);
+		panic("Cannot mmap RX_RING!\n");
+	}
+}
+
+void alloc_rx_ring_frames(struct ring *ring)
+{
+	int i;
+	size_t len = ring->layout.tp_frame_nr * sizeof(*ring->frames);
+
+	ring->frames = xmalloc_aligned(len, CO_CACHE_LINE_SIZE);
+	fmemset(ring->frames, 0, len);
+
+	for (i = 0; i < ring->layout.tp_frame_nr; ++i) {
+		ring->frames[i].iov_len = ring->layout.tp_frame_size;
+		ring->frames[i].iov_base = ring->mm_space +
+					   (i * ring->layout.tp_frame_size);
+	}
+}
+
+void bind_rx_ring(int sock, struct ring *ring, int ifindex)
+{
+	int ret;
+	/*
+	 * The RX_RING registers itself to the networking stack with
+	 * dev_add_pack(), so we have one single RX_RING for all devs
+	 * otherwise you'll get the packet twice.
+	 */
+	fmemset(&ring->s_ll, 0, sizeof(ring->s_ll));
+
+	ring->s_ll.sll_family = AF_PACKET;
+	ring->s_ll.sll_protocol = htons(ETH_P_ALL);
+	ring->s_ll.sll_ifindex = ifindex;
+	ring->s_ll.sll_hatype = 0;
+	ring->s_ll.sll_halen = 0;
+	ring->s_ll.sll_pkttype = 0;
+
+	ret = bind(sock, (struct sockaddr *) &ring->s_ll, sizeof(ring->s_ll));
+	if (ret < 0) {
+		destroy_rx_ring(sock, ring);
+		panic("Cannot bind RX_RING!\n");
+	}
+}