Build the Ethernet, IP, and TCP headers on the stack instead of
directly in the buffer via pointer casts, then write them into the
iovec with IOV_PUSH_HEADER(). This mirrors the approach already used
in tcp_vu_prepare() and udp_vu_prepare().
Remove the vu_eth(), vu_ip(), vu_payloadv4() and vu_payloadv6() helpers
from vu_common.h, as they are no longer used anywhere.
Introduce tcp_vu_send_dup() to handle DUP_ACK duplication using
vu_collect() and iov_memcpy() instead of a plain memcpy(), so that
the duplicated frame is also properly scattered across multiple iovecs.
Signed-off-by: Laurent Vivier
Reviewed-by: Jon Maloy
---
iov.c | 1 -
tcp_vu.c | 156 ++++++++++++++++++++++++++++++----------------------
vu_common.h | 20 -------
3 files changed, 91 insertions(+), 86 deletions(-)
diff --git a/iov.c b/iov.c
index 9248ba95a9f2..6fd684ad1a6b 100644
--- a/iov.c
+++ b/iov.c
@@ -208,7 +208,6 @@ void iov_memset(const struct iovec *iov, size_t iov_cnt, size_t offset, int c,
*
* Return: total number of bytes copied
*/
-/* cppcheck-suppress unusedFunction */
size_t iov_memcpy(struct iovec *dst_iov, size_t dst_iov_cnt, size_t dst_offset,
const struct iovec *src_iov, size_t src_iov_cnt,
size_t src_offset, size_t length)
diff --git a/tcp_vu.c b/tcp_vu.c
index 55242ec40410..30633760e4ec 100644
--- a/tcp_vu.c
+++ b/tcp_vu.c
@@ -74,6 +74,43 @@ static size_t tcp_vu_hdrlen(bool v6)
return hdrlen;
}
+/**
+ * tcp_vu_send_dup() - Duplicate a frame into a new virtqueue element
+ * @c: Execution context
+ * @vq: Receive virtqueue
+ * @dest_elem: Destination virtqueue element to collect
+ * @dest_iov: Destination iovec array for collected buffers
+ * @max_dest_iov: Maximum number of entries in @dest_iov
+ * @src_iov: Source iovec array containing the frame to duplicate
+ * @src_cnt: Number of entries in @src_iov
+ * @vnlen: Total frame length including virtio-net header
+ *
+ * Return: number of virtqueue elements collected (0 if none available)
+ */
+static int tcp_vu_send_dup(const struct ctx *c, struct vu_virtq *vq,
+ struct vu_virtq_element *dest_elem,
+ struct iovec *dest_iov, size_t max_dest_iov,
+ const struct iovec *src_iov, size_t src_cnt,
+ size_t vnlen)
+{
+ const struct vu_dev *vdev = c->vdev;
+ size_t dest_cnt;
+ int elem_cnt;
+
+ elem_cnt = vu_collect(vdev, vq, dest_elem, 1, dest_iov, max_dest_iov,
+ &dest_cnt, vnlen, NULL);
+ if (elem_cnt == 0)
+ return 0;
+
+ iov_memcpy(dest_iov, dest_cnt, 0, src_iov, src_cnt, 0,
+ MAX(VNET_HLEN + ETH_ZLEN, vnlen));
+
+ if (*c->pcap)
+ pcap_iov(dest_iov, dest_cnt, VNET_HLEN, vnlen - VNET_HLEN);
+
+ return elem_cnt;
+}
+
/**
* tcp_vu_send_flag() - Send segment with flags to vhost-user (no payload)
* @c: Execution context
@@ -88,97 +125,86 @@ int tcp_vu_send_flag(const struct ctx *c, struct tcp_tap_conn *conn, int flags)
{
struct vu_dev *vdev = c->vdev;
struct vu_virtq *vq = &vdev->vq[VHOST_USER_RX_QUEUE];
+ size_t optlen, hdrlen, iov_cnt, iov_used;
struct vu_virtq_element flags_elem[2];
- size_t optlen, hdrlen, l2len;
- struct ipv6hdr *ip6h = NULL;
- struct iphdr *ip4h = NULL;
- struct iovec flags_iov[2];
- struct tcp_syn_opts *opts;
- struct iov_tail payload;
- struct tcphdr *th;
- struct ethhdr *eh;
+ struct iov_tail payload, l2frame;
+ int elem_cnt, dup_elem_cnt = 0;
+ struct iovec flags_iov[64];
+ struct tcp_syn_opts opts;
+ struct tcphdr th = { 0 };
+ struct ipv6hdr ip6h;
+ struct iphdr ip4h;
+ struct ethhdr eh;
uint32_t seq;
- int elem_cnt;
int ret;
hdrlen = tcp_vu_hdrlen(CONN_V6(conn));
elem_cnt = vu_collect(vdev, vq, &flags_elem[0], 1,
- &flags_iov[0], 1, NULL,
- hdrlen + sizeof(*opts), NULL);
- if (elem_cnt != 1)
+ flags_iov, ARRAY_SIZE(flags_iov), &iov_cnt,
+ hdrlen + sizeof(opts), NULL);
+ if (elem_cnt == 0)
return -EAGAIN;
- assert(flags_elem[0].in_num == 1);
- assert(flags_elem[0].in_sg[0].iov_len >=
- MAX(hdrlen + sizeof(*opts), ETH_ZLEN + VNET_HLEN));
-
- eh = vu_eth(flags_elem[0].in_sg[0].iov_base);
-
- memcpy(eh->h_dest, c->guest_mac, sizeof(eh->h_dest));
- memcpy(eh->h_source, c->our_tap_mac, sizeof(eh->h_source));
-
- if (CONN_V4(conn)) {
- eh->h_proto = htons(ETH_P_IP);
-
- ip4h = vu_ip(flags_elem[0].in_sg[0].iov_base);
- *ip4h = (struct iphdr)L2_BUF_IP4_INIT(IPPROTO_TCP);
-
- th = vu_payloadv4(flags_elem[0].in_sg[0].iov_base);
- } else {
- eh->h_proto = htons(ETH_P_IPV6);
-
- ip6h = vu_ip(flags_elem[0].in_sg[0].iov_base);
- *ip6h = (struct ipv6hdr)L2_BUF_IP6_INIT(IPPROTO_TCP);
- th = vu_payloadv6(flags_elem[0].in_sg[0].iov_base);
- }
+ memcpy(eh.h_dest, c->guest_mac, sizeof(eh.h_dest));
- memset(th, 0, sizeof(*th));
- th->doff = sizeof(*th) / 4;
- th->ack = 1;
+ if (CONN_V4(conn))
+ ip4h = (struct iphdr)L2_BUF_IP4_INIT(IPPROTO_TCP);
+ else
+ ip6h = (struct ipv6hdr)L2_BUF_IP6_INIT(IPPROTO_TCP);
seq = conn->seq_to_tap;
- opts = (struct tcp_syn_opts *)(th + 1);
- ret = tcp_prepare_flags(c, conn, flags, th, opts, &optlen);
+ ret = tcp_prepare_flags(c, conn, flags, &th, &opts, &optlen);
if (ret <= 0) {
- vu_queue_rewind(vq, 1);
+ vu_queue_rewind(vq, elem_cnt);
return ret;
}
- payload = IOV_TAIL(flags_elem[0].in_sg, 1, hdrlen);
-
if (flags & KEEPALIVE)
seq--;
- tcp_fill_headers(c, conn, eh, ip4h, ip6h, th, &payload,
+ iov_used = iov_skip_bytes(flags_iov, iov_cnt,
+ MAX(optlen + hdrlen, VNET_HLEN + ETH_ZLEN),
+ NULL);
+ if (iov_used < iov_cnt)
+ iov_used++;
+ iov_cnt = iov_used;
+
+ payload = IOV_TAIL(flags_elem[0].in_sg, iov_cnt, hdrlen);
+ iov_from_buf(payload.iov, payload.cnt, payload.off, &opts, optlen);
+ tcp_fill_headers(c, conn, &eh, CONN_V4(conn) ? &ip4h : NULL,
+ CONN_V6(conn) ? &ip6h : NULL, &th, &payload,
optlen, IP4_CSUM | (*c->pcap ? TCP_CSUM : 0), seq);
- vu_pad(flags_elem[0].in_sg, 1, hdrlen + optlen);
- vu_flush(vdev, vq, flags_elem, 1, hdrlen + optlen);
+ vu_pad(flags_elem[0].in_sg, iov_cnt, hdrlen + optlen);
+
+ /* write headers */
+ l2frame = IOV_TAIL(flags_elem[0].in_sg, iov_cnt, VNET_HLEN);
+
+ IOV_PUSH_HEADER(&l2frame, eh);
+ if (CONN_V4(conn))
+ IOV_PUSH_HEADER(&l2frame, ip4h);
+ else
+ IOV_PUSH_HEADER(&l2frame, ip6h);
+ IOV_PUSH_HEADER(&l2frame, th);
- l2len = hdrlen + optlen - VNET_HLEN;
if (*c->pcap)
- pcap_iov(&flags_elem[0].in_sg[0], 1, VNET_HLEN, l2len);
+ pcap_iov(flags_elem[0].in_sg, iov_cnt, VNET_HLEN,
+ hdrlen + optlen - VNET_HLEN);
if (flags & DUP_ACK) {
- elem_cnt = vu_collect(vdev, vq, &flags_elem[1], 1,
- &flags_iov[1], 1, NULL,
- hdrlen + optlen, NULL);
- if (elem_cnt == 1 &&
- flags_elem[1].in_sg[0].iov_len >=
- flags_elem[0].in_sg[0].iov_len) {
- memcpy(flags_elem[1].in_sg[0].iov_base,
- flags_elem[0].in_sg[0].iov_base,
- flags_elem[0].in_sg[0].iov_len);
-
- vu_flush(vdev, vq, &flags_elem[1], 1, hdrlen + optlen);
-
- if (*c->pcap) {
- pcap_iov(&flags_elem[1].in_sg[0], 1, VNET_HLEN,
- l2len);
- }
- }
+ dup_elem_cnt = tcp_vu_send_dup(c, vq, &flags_elem[elem_cnt],
+ &flags_iov[iov_cnt],
+ ARRAY_SIZE(flags_iov) - iov_cnt,
+ flags_elem[0].in_sg, iov_cnt,
+ hdrlen + optlen);
}
+ vu_flush(vdev, vq, flags_elem, elem_cnt, hdrlen + optlen);
+ if (dup_elem_cnt) {
+ vu_flush(vdev, vq, &flags_elem[elem_cnt], dup_elem_cnt,
+ hdrlen + optlen);
+ }
+
vu_queue_notify(vdev, vq);
return 0;
diff --git a/vu_common.h b/vu_common.h
index 51f70084a7cb..817384175a1d 100644
--- a/vu_common.h
+++ b/vu_common.h
@@ -15,26 +15,6 @@
#include "ip.h"
#include "virtio.h"
-static inline void *vu_eth(void *base)
-{
- return ((char *)base + VNET_HLEN);
-}
-
-static inline void *vu_ip(void *base)
-{
- return (struct ethhdr *)vu_eth(base) + 1;
-}
-
-static inline void *vu_payloadv4(void *base)
-{
- return (struct iphdr *)vu_ip(base) + 1;
-}
-
-static inline void *vu_payloadv6(void *base)
-{
- return (struct ipv6hdr *)vu_ip(base) + 1;
-}
-
int vu_collect(const struct vu_dev *vdev, struct vu_virtq *vq,
struct vu_virtq_element *elem, int max_elem,
struct iovec *in_sg, size_t max_in_sg, size_t *in_total,
--
2.54.0