udp_vu_sock_recv() currently mixes two concerns: receiving data from the
socket and managing virtqueue buffers (collecting, rewinding, releasing).
This makes the function harder to reason about and couples socket I/O
with virtqueue state.
Move all virtqueue operations, vu_collect(), vu_init_elem(),
vu_queue_rewind(), vu_set_vnethdr(), and the queue-readiness check, into
udp_vu_sock_to_tap(), which is the only caller. This turns
udp_vu_sock_recv() into a pure socket receive function that simply reads
into the provided iov array and adjusts its length.
Signed-off-by: Laurent Vivier
---
udp_vu.c | 110 +++++++++++++++++++++++++------------------------------
1 file changed, 49 insertions(+), 61 deletions(-)
diff --git a/udp_vu.c b/udp_vu.c
index 6638cb0ddc5f..dc949e30a793 100644
--- a/udp_vu.c
+++ b/udp_vu.c
@@ -33,9 +33,6 @@
#include "udp_vu.h"
#include "vu_common.h"
-static struct iovec iov_vu [VIRTQUEUE_MAX_SIZE];
-static struct vu_virtq_element elem [VIRTQUEUE_MAX_SIZE];
-
/**
* udp_vu_hdrlen() - Sum size of all headers, from UDP to virtio-net
* @v6: Set for IPv6 packet
@@ -58,78 +55,35 @@ static size_t udp_vu_hdrlen(bool v6)
/**
* udp_vu_sock_recv() - Receive datagrams from socket into vhost-user buffers
- * @c: Execution context
* @iov: IO vector for the frame (in/out)
* @cnt: Number of IO vector entries (in/out)
- * @vq: virtqueue to use to receive data
* @s: Socket to receive from
* @v6: Set for IPv6 connections
*
- * Return: size of received data, 0 if the datagram
- * was discarded because the virtqueue is not ready, -1 on error
+ * Return: size of received data, -1 on error
*/
-static ssize_t udp_vu_sock_recv(const struct ctx *c, struct iovec *iov,
- size_t *cnt, unsigned *elem_used,
- struct vu_virtq *vq, int s, bool v6)
+static ssize_t udp_vu_sock_recv(struct iovec *iov, size_t *cnt, int s, bool v6)
{
- const struct vu_dev *vdev = c->vdev;
- struct msghdr msg = { 0 };
+ struct iovec msg_iov[*cnt];
+ struct msghdr msg = { 0 };
struct iov_tail payload;
- size_t hdrlen, iov_used;
- unsigned elem_cnt;
- unsigned i, j;
+ size_t hdrlen;
ssize_t dlen;
- assert(!c->no_udp);
-
- if (!vu_queue_enabled(vq) || !vu_queue_started(vq)) {
- debug("Got UDP packet, but RX virtqueue not usable yet");
-
- if (recvmsg(s, &msg, MSG_DONTWAIT) < 0)
- debug_perror("Failed to discard datagram");
-
- *cnt = 0;
- return 0;
- }
-
/* compute L2 header length */
hdrlen = udp_vu_hdrlen(v6);
- elem_cnt = vu_collect(vdev, vq, elem, ARRAY_SIZE(elem),
- iov, *cnt, &iov_used,
- IP_MAX_MTU + ETH_HLEN + VNET_HLEN, NULL);
- if (elem_cnt == 0)
- return -1;
-
- assert((size_t)elem_cnt == iov_used); /* one iovec per element */
-
- payload = IOV_TAIL(iov, iov_used, hdrlen);
+ payload = IOV_TAIL(iov, *cnt, hdrlen);
- struct iovec msg_iov[payload.cnt];
msg.msg_iov = msg_iov;
msg.msg_iovlen = iov_tail_clone(msg.msg_iov, payload.cnt, &payload);
/* read data from the socket */
dlen = recvmsg(s, &msg, 0);
- if (dlen < 0) {
- vu_queue_rewind(vq, elem_cnt);
+ if (dlen < 0)
return -1;
- }
-
- *cnt = vu_pad(iov, iov_used, 0, dlen + hdrlen);
-
- *elem_used = 0;
- for (i = 0, j = 0; j < *cnt && i < elem_cnt; i++) {
- if (j + elem[i].in_num > *cnt)
- elem[i].in_num = *cnt - j;
- j += elem[i].in_num;
- (*elem_used)++;
- }
- vu_set_vnethdr(iov[0].iov_base, *elem_used);
-
- /* release unused buffers */
- vu_queue_rewind(vq, elem_cnt - *elem_used);
+ *cnt = vu_pad(iov, *cnt, 0, dlen + hdrlen);
return dlen;
}
@@ -217,26 +171,60 @@ static void udp_vu_csum(const struct flowside *toside,
*/
void udp_vu_sock_to_tap(const struct ctx *c, int s, int n, flow_sidx_t tosidx)
{
+ static struct iovec iov_vu [VIRTQUEUE_MAX_SIZE];
+ static struct vu_virtq_element elem [VIRTQUEUE_MAX_SIZE];
const struct flowside *toside = flowside_at_sidx(tosidx);
bool v6 = !(inany_v4(&toside->eaddr) && inany_v4(&toside->oaddr));
struct vu_dev *vdev = c->vdev;
struct vu_virtq *vq = &vdev->vq[VHOST_USER_RX_QUEUE];
- struct iov_tail data;
int i;
+ assert(!c->no_udp);
+
+ if (!vu_queue_enabled(vq) || !vu_queue_started(vq)) {
+ struct msghdr msg = { 0 };
+
+ debug("Got UDP packet, but RX virtqueue not usable yet");
+
+ for (i = 0; i < n; i++) {
+ if (recvmsg(s, &msg, MSG_DONTWAIT) < 0)
+ debug_perror("Failed to discard datagram");
+ }
+
+ return;
+ }
+
for (i = 0; i < n; i++) {
- unsigned elem_used;
+ unsigned elem_used, elem_cnt, j, k;
size_t iov_cnt;
ssize_t dlen;
- iov_cnt = ARRAY_SIZE(iov_vu);
- dlen = udp_vu_sock_recv(c, iov_vu, &iov_cnt, &elem_used, vq,
- s, v6);
- if (dlen < 0)
+ elem_cnt = vu_collect(vdev, vq, elem, ARRAY_SIZE(elem),
+ iov_vu, ARRAY_SIZE(iov_vu), &iov_cnt,
+ IP_MAX_MTU + ETH_HLEN + VNET_HLEN, NULL);
+ if (elem_cnt == 0)
+ break;
+
+ dlen = udp_vu_sock_recv(iov_vu, &iov_cnt, s, v6);
+ if (dlen < 0) {
+ vu_queue_rewind(vq, elem_cnt);
break;
+ }
+
+ elem_used = 0;
+ for (j = 0, k = 0; k < iov_cnt && j < elem_cnt; j++) {
+ if (k + elem[j].in_num > iov_cnt)
+ elem[j].in_num = iov_cnt - k;
+ k += elem[j].in_num;
+ elem_used++;
+ }
+
+ /* release unused buffers */
+ vu_queue_rewind(vq, elem_cnt - elem_used);
if (iov_cnt > 0) {
- data = IOV_TAIL(iov_vu, iov_cnt, 0);
+ struct iov_tail data = IOV_TAIL(iov_vu, iov_cnt, 0);
+ vu_set_vnethdr(iov_vu[0].iov_base, elem_used);
udp_vu_prepare(c, &data, toside, dlen);
if (*c->pcap) {
udp_vu_csum(toside, &data);
--
2.53.0