1 files changed, 285 insertions, 0 deletions
diff --git a/vu_common.c b/vu_common.c
new file mode 100644
index 0000000..4291fda
--- /dev/null
+++ b/vu_common.c
@@ -0,0 +1,285 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Copyright Red Hat
+ * Author: Laurent Vivier <lvivier@redhat.com>
+ *
+ * common_vu.c - vhost-user common UDP and TCP functions
+ */
+
+#include <unistd.h>
+#include <sys/uio.h>
+#include <sys/eventfd.h>
+#include <linux/virtio_net.h>
+
+#include "util.h"
+#include "passt.h"
+#include "tap.h"
+#include "vhost_user.h"
+#include "pcap.h"
+#include "vu_common.h"
+
+/**
+ * vu_packet_check_range() - Check if a given memory zone is contained in
+ * 			     a mapped guest memory region
+ * @buf:	Array of the available memory regions
+ * @offset:	Offset of data range in packet descriptor
+ * @size:	Length of desired data range
+ * @start:	Start of the packet descriptor
+ *
+ * Return: 0 if the zone is in a mapped memory region, -1 otherwise
+ */
+int vu_packet_check_range(void *buf, size_t offset, size_t len,
+			  const char *start)
+{
+	struct vu_dev_region *dev_region;
+
+	for (dev_region = buf; dev_region->mmap_addr; dev_region++) {
+		/* NOLINTNEXTLINE(performance-no-int-to-ptr) */
+		char *m = (char *)dev_region->mmap_addr;
+
+		if (m <= start &&
+		    start + offset + len <= m + dev_region->mmap_offset +
+					       dev_region->size)
+			return 0;
+	}
+
+	return -1;
+}
+
+/**
+ * vu_init_elem() - initialize an array of virtqueue element with 1 iov in each
+ * @elem:	Array of virtqueue element to initialize
+ * @iov:	Array of iovec to assign to virtqueue element
+ * @elem_cnt:	Number of virtqueue element
+ */
+void vu_init_elem(struct vu_virtq_element *elem, struct iovec *iov, int elem_cnt)
+{
+	int i;
+
+	for (i = 0; i < elem_cnt; i++)
+		vu_set_element(&elem[i], NULL, &iov[i]);
+}
+
+/**
+ * vu_collect() - collect virtio buffers from a given virtqueue
+ * @vdev:		vhost-user device
+ * @vq:			virtqueue to collect from
+ * @elem:		Array of virtqueue element
+ * 			each element must be initialized with one iovec entry
+ * 			in the in_sg array.
+ * @max_elem:		Number of virtqueue element in the array
+ * @size:		Maximum size of the data in the frame
+ * @frame_size:		The total size of the buffers (output)
+ *
+ * Return: number of elements used to contain the frame
+ */
+int vu_collect(struct vu_dev *vdev, struct vu_virtq *vq,
+	       struct vu_virtq_element *elem, int max_elem,
+	       size_t size, size_t *frame_size)
+{
+	size_t current_size = 0;
+	int elem_cnt = 0;
+
+	while (current_size < size && elem_cnt < max_elem) {
+		struct iovec *iov;
+		int ret;
+
+		ret = vu_queue_pop(vdev, vq, &elem[elem_cnt]);
+		if (ret < 0)
+			break;
+
+		if (elem[elem_cnt].in_num < 1) {
+			warn("virtio-net receive queue contains no in buffers");
+			vu_queue_detach_element(vq);
+			break;
+		}
+
+		iov = &elem[elem_cnt].in_sg[0];
+
+		if (iov->iov_len > size - current_size)
+			iov->iov_len = size - current_size;
+
+		current_size += iov->iov_len;
+		elem_cnt++;
+
+		if (!vu_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF))
+			break;
+	}
+
+	if (frame_size)
+		*frame_size = current_size;
+
+	return elem_cnt;
+}
+
+/**
+ * vu_set_vnethdr() - set virtio-net headers
+ * @vdev:		vhost-user device
+ * @vnethdr:		Address of the header to set
+ * @num_buffers:	Number of guest buffers of the frame
+ */
+void vu_set_vnethdr(const struct vu_dev *vdev,
+		    struct virtio_net_hdr_mrg_rxbuf *vnethdr,
+		    int num_buffers)
+{
+	vnethdr->hdr = VU_HEADER;
+	if (vu_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF))
+		vnethdr->num_buffers = htole16(num_buffers);
+}
+
+/**
+ * vu_flush() - flush all the collected buffers to the vhost-user interface
+ * @vdev:	vhost-user device
+ * @vq:		vhost-user virtqueue
+ * @elem:	virtqueue element array to send back to the virqueue
+ * @iov_used:	Length of the array
+ */
+void vu_flush(const struct vu_dev *vdev, struct vu_virtq *vq,
+	      struct vu_virtq_element *elem, int elem_cnt)
+{
+	int i;
+
+	for (i = 0; i < elem_cnt; i++)
+		vu_queue_fill(vq, &elem[i], elem[i].in_sg[0].iov_len, i);
+
+	vu_queue_flush(vq, elem_cnt);
+	vu_queue_notify(vdev, vq);
+}
+
+/**
+ * vu_handle_tx() - Receive data from the TX virtqueue
+ * @vdev:	vhost-user device
+ * @index:	index of the virtqueue
+ * @now:	Current timestamp
+ */
+static void vu_handle_tx(struct vu_dev *vdev, int index,
+			 const struct timespec *now)
+{
+	struct vu_virtq_element elem[VIRTQUEUE_MAX_SIZE];
+	struct iovec out_sg[VIRTQUEUE_MAX_SIZE];
+	struct vu_virtq *vq = &vdev->vq[index];
+	int hdrlen = sizeof(struct virtio_net_hdr_mrg_rxbuf);
+	int out_sg_count;
+	int count;
+
+	if (!VHOST_USER_IS_QUEUE_TX(index)) {
+		debug("vhost-user: index %d is not a TX queue", index);
+		return;
+	}
+
+	tap_flush_pools();
+
+	count = 0;
+	out_sg_count = 0;
+	while (count < VIRTQUEUE_MAX_SIZE) {
+		int ret;
+
+		vu_set_element(&elem[count], &out_sg[out_sg_count], NULL);
+		ret = vu_queue_pop(vdev, vq, &elem[count]);
+		if (ret < 0)
+			break;
+		out_sg_count += elem[count].out_num;
+
+		if (elem[count].out_num < 1) {
+			warn("virtio-net transmit queue contains no out buffers");
+			break;
+		}
+		ASSERT(elem[count].out_num == 1);
+
+		tap_add_packet(vdev->context,
+			       elem[count].out_sg[0].iov_len - hdrlen,
+			       (char *)elem[count].out_sg[0].iov_base + hdrlen);
+		count++;
+	}
+	tap_handler(vdev->context, now);
+
+	if (count) {
+		int i;
+
+		for (i = 0; i < count; i++)
+			vu_queue_fill(vq, &elem[i], 0, i);
+		vu_queue_flush(vq, count);
+		vu_queue_notify(vdev, vq);
+	}
+}
+
+/**
+ * vu_kick_cb() - Called on a kick event to start to receive data
+ * @vdev:	vhost-user device
+ * @ref:	epoll reference information
+ * @now:	Current timestamp
+ */
+void vu_kick_cb(struct vu_dev *vdev, union epoll_ref ref,
+		const struct timespec *now)
+{
+	eventfd_t kick_data;
+	ssize_t rc;
+
+	rc = eventfd_read(ref.fd, &kick_data);
+	if (rc == -1)
+		die_perror("vhost-user kick eventfd_read()");
+
+	debug("vhost-user: ot kick_data: %016"PRIx64" idx:%d",
+	      kick_data, ref.queue);
+	if (VHOST_USER_IS_QUEUE_TX(ref.queue))
+		vu_handle_tx(vdev, ref.queue, now);
+}
+
+/**
+ * vu_send_single() - Send a buffer to the front-end using the RX virtqueue
+ * @c:		execution context
+ * @buf:	address of the buffer
+ * @size:	size of the buffer
+ *
+ * Return: number of bytes sent, -1 if there is an error
+ */
+int vu_send_single(const struct ctx *c, const void *buf, size_t size)
+{
+	struct vu_dev *vdev = c->vdev;
+	struct vu_virtq *vq = &vdev->vq[VHOST_USER_RX_QUEUE];
+	struct vu_virtq_element elem[VIRTQUEUE_MAX_SIZE];
+	struct iovec in_sg[VIRTQUEUE_MAX_SIZE];
+	size_t total;
+	int elem_cnt;
+	int i;
+
+	debug("vu_send_single size %zu", size);
+
+	if (!vu_queue_enabled(vq) || !vu_queue_started(vq)) {
+		err("Got packet, but RX virtqueue not usable yet");
+		return 0;
+	}
+
+	vu_init_elem(elem, in_sg, VIRTQUEUE_MAX_SIZE);
+
+	size += sizeof(struct virtio_net_hdr_mrg_rxbuf);
+	elem_cnt = vu_collect(vdev, vq, elem, VIRTQUEUE_MAX_SIZE, size, &total);
+	if (total < size) {
+		debug("vu_send_single: no space to send the data "
+		      "elem_cnt %d size %zd", elem_cnt, total);
+		goto err;
+	}
+
+	vu_set_vnethdr(vdev, in_sg[0].iov_base, elem_cnt);
+
+	total -= sizeof(struct virtio_net_hdr_mrg_rxbuf);
+
+	/* copy data from the buffer to the iovec */
+	iov_from_buf(in_sg, elem_cnt, sizeof(struct virtio_net_hdr_mrg_rxbuf),
+		     buf, total);
+
+	if (*c->pcap) {
+		pcap_iov(in_sg, elem_cnt,
+			 sizeof(struct virtio_net_hdr_mrg_rxbuf));
+	}
+
+	vu_flush(vdev, vq, elem, elem_cnt);
+
+	debug("vhost-user sent %zu", total);
+
+	return total;
+err:
+	for (i = 0; i < elem_cnt; i++)
+		vu_queue_detach_element(vq);
+
+	return -1;
+}