tcp_vu_send_flag() previously used vu_eth(), vu_ip(), vu_payloadv4() and
vu_payloadv6() to access headers via direct pointer arithmetic on a
single contiguous buffer. Replace these with iov_tail-based
with_header() and IOV_DROP_HEADER() accessors, which work correctly with
multi-buffer virtio descriptors.
Enlarge the flags_iov and flags_elem arrays to accommodate split
descriptors, and pass iov_cnt through vu_collect() so we track
how many iovecs the frame actually spans.
Extract a tcp_vu_send_dup() helper for the DUP_ACK path that uses
iov_memcopy() to duplicate a frame across potentially multi-buffer
descriptors, replacing the previous single-buffer memcpy.
With all callers converted, remove the vu_eth(), vu_ip(),
vu_payloadv4() and vu_payloadv6() inline helpers from vu_common.h,
and drop the cppcheck-suppress annotation on iov_memcopy() which is
now used.
Signed-off-by: Laurent Vivier
---
iov.c | 1 -
tcp_vu.c | 113 ++++++++++++++++++++++++++++------------------------
vu_common.h | 20 ----------
3 files changed, 62 insertions(+), 72 deletions(-)
diff --git a/iov.c b/iov.c
index 55263ec10b44..9638dc6de03d 100644
--- a/iov.c
+++ b/iov.c
@@ -207,7 +207,6 @@ 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_memcopy(struct iovec *dst_iov, size_t dst_iov_cnt, size_t dst_offs,
const struct iovec *iov, size_t iov_cnt, size_t offs)
{
diff --git a/tcp_vu.c b/tcp_vu.c
index d6bd6a34d6da..776b47aea18c 100644
--- a/tcp_vu.c
+++ b/tcp_vu.c
@@ -74,6 +74,41 @@ 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
+ *
+ * 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 dest_cnt, frame_size = iov_size(src_iov, src_cnt);
+ const struct vu_dev *vdev = c->vdev;
+ int elem_cnt;
+
+ elem_cnt = vu_collect(vdev, vq, dest_elem, 1, dest_iov, max_dest_iov,
+ &dest_cnt, frame_size, NULL);
+ if (elem_cnt == 0)
+ return 0;
+
+ vu_pad(dest_iov, dest_cnt, 0, frame_size);
+ iov_memcopy(dest_iov, dest_cnt, 0, src_iov, src_cnt, 0);
+
+ if (*c->pcap)
+ pcap_iov(dest_iov, dest_cnt, VNET_HLEN);
+
+ return elem_cnt;
+}
+
/**
* tcp_vu_send_flag() - Send segment with flags to vhost-user (no payload)
* @c: Execution context
@@ -87,13 +122,9 @@ 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];
struct vu_virtq_element flags_elem[2];
- struct ipv6hdr *ip6h = NULL;
- struct iphdr *ip4h = NULL;
- struct iovec flags_iov[2];
+ size_t optlen, hdrlen, iov_cnt;
+ struct iovec flags_iov[64];
struct iov_tail payload;
- size_t optlen, hdrlen;
- struct tcphdr *th;
- struct ethhdr *eh;
uint32_t seq;
int elem_cnt;
int nb_ack;
@@ -102,77 +133,57 @@ int tcp_vu_send_flag(const struct ctx *c, struct tcp_tap_conn *conn, int flags)
hdrlen = tcp_vu_hdrlen(CONN_V6(conn));
elem_cnt = vu_collect(vdev, vq, &flags_elem[0], 1,
- &flags_iov[0], 1, NULL,
+ flags_iov, ARRAY_SIZE(flags_iov), &iov_cnt,
hdrlen + sizeof(struct tcp_syn_opts), NULL);
- if (elem_cnt != 1)
+ if (elem_cnt == 0)
return -1;
- assert(flags_elem[0].in_num == 1);
- assert(flags_elem[0].in_sg[0].iov_len >=
- MAX(hdrlen + sizeof(struct tcp_syn_opts), ETH_ZLEN + VNET_HLEN));
-
- vu_set_vnethdr(flags_elem[0].in_sg[0].iov_base, 1);
+ vu_set_vnethdr(flags_elem[0].in_sg[0].iov_base, elem_cnt);
- eh = vu_eth(flags_elem[0].in_sg[0].iov_base);
+ payload = IOV_TAIL(flags_elem[0].in_sg, iov_cnt, VNET_HLEN);
- memcpy(eh->h_dest, c->guest_mac, sizeof(eh->h_dest));
- memcpy(eh->h_source, c->our_tap_mac, sizeof(eh->h_source));
+ with_header(struct ethhdr, eh, &payload)
+ memcpy(eh->h_dest, c->guest_mac, sizeof(eh->h_dest));
+ IOV_DROP_HEADER(&payload, struct ethhdr);
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);
+ with_header(struct iphdr, ip4h, &payload)
+ *ip4h = (struct iphdr)L2_BUF_IP4_INIT(IPPROTO_TCP);
+ IOV_DROP_HEADER(&payload, struct iphdr);
} 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);
+ with_header(struct ipv6hdr, ip6h, &payload)
+ *ip6h = (struct ipv6hdr)L2_BUF_IP6_INIT(IPPROTO_TCP);
+ IOV_DROP_HEADER(&payload, struct ipv6hdr);
}
- memset(th, 0, sizeof(*th));
- th->doff = sizeof(*th) / 4;
- th->ack = 1;
+ with_header(struct tcphdr, th, &payload)
+ memset(th, 0, sizeof(*th));
seq = conn->seq_to_tap;
- payload = IOV_TAIL(flags_elem[0].in_sg, 1, hdrlen - sizeof(*th));
ret = tcp_prepare_flags(c, conn, flags, &payload, &optlen);
if (ret <= 0) {
- vu_queue_rewind(vq, 1);
+ vu_queue_rewind(vq, elem_cnt);
return ret;
}
- vu_pad(&flags_iov[0], 1, 0, hdrlen + optlen);
+ vu_pad(flags_elem[0].in_sg, iov_cnt, 0, hdrlen + optlen);
if (flags & KEEPALIVE)
seq--;
- payload = IOV_TAIL(flags_elem[0].in_sg, 1, VNET_HLEN);
+ payload = IOV_TAIL(flags_elem[0].in_sg, iov_cnt, VNET_HLEN);
tcp_fill_headers(c, conn, CONN_V4(conn), &payload, -1, seq, !*c->pcap);
if (*c->pcap)
- pcap_iov(&flags_elem[0].in_sg[0], 1, VNET_HLEN);
- nb_ack = 1;
+ pcap_iov(flags_elem[0].in_sg, iov_cnt, VNET_HLEN);
+ nb_ack = elem_cnt;
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) {
- vu_pad(&flags_iov[1], 1, 0, hdrlen + optlen);
- 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);
- nb_ack++;
-
- if (*c->pcap)
- pcap_iov(&flags_elem[1].in_sg[0], 1, VNET_HLEN);
- }
+ 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);
+ nb_ack += elem_cnt;
}
vu_flush(vdev, vq, flags_elem, nb_ack);
diff --git a/vu_common.h b/vu_common.h
index f09dd25d3d1f..8e42ce88b2ab 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,
--
2.53.0