With vhost-user multibuffer frames, the iov can be larger than the
actual L2 frame. The previous approach of computing L2 length as
iov_size() - offset would overcount and write extra bytes into the
pcap file.
Pass the L2 frame length explicitly to pcap_frame() and pcap_iov(),
and write exactly that many bytes instead of the full iov remainder.
Signed-off-by: Laurent Vivier
---
pcap.c | 37 ++++++++++++++++++++++++++++---------
pcap.h | 2 +-
tap.c | 2 +-
tcp_vu.c | 9 ++++++---
udp_vu.c | 4 +++-
vu_common.c | 2 +-
6 files changed, 40 insertions(+), 16 deletions(-)
diff --git a/pcap.c b/pcap.c
index a026f17e7974..dfe1c61add9a 100644
--- a/pcap.c
+++ b/pcap.c
@@ -52,22 +52,38 @@ struct pcap_pkthdr {
* @iov: IO vector containing frame (with L2 headers and tap headers)
* @iovcnt: Number of buffers (@iov entries) in frame
* @offset: Byte offset of the L2 headers within @iov
+ * @l2len: Length of L2 frame data to capture
* @now: Timestamp
*/
static void pcap_frame(const struct iovec *iov, size_t iovcnt,
- size_t offset, const struct timespec *now)
+ size_t offset, size_t l2len, const struct timespec *now)
{
- size_t l2len = iov_size(iov, iovcnt) - offset;
struct pcap_pkthdr h = {
.tv_sec = now->tv_sec,
.tv_usec = DIV_ROUND_CLOSEST(now->tv_nsec, 1000),
.caplen = l2len,
.len = l2len
};
+ size_t i;
- if (write_all_buf(pcap_fd, &h, sizeof(h)) < 0 ||
- write_remainder(pcap_fd, iov, iovcnt, offset) < 0)
- debug_perror("Cannot log packet, length %zu", l2len);
+ if (write_all_buf(pcap_fd, &h, sizeof(h)) < 0) {
+ debug_perror("Cannot log packet, packet header error");
+ return;
+ }
+
+ for (i = iov_skip_bytes(iov, iovcnt, offset, &offset);
+ i < iovcnt && l2len; i++) {
+ size_t n = MIN(l2len, iov[i].iov_len - offset);
+
+ if (write_all_buf(pcap_fd, (char *)iov[i].iov_base + offset,
+ n) < 0) {
+ debug_perror("Cannot log packet");
+ return;
+ }
+
+ offset = 0;
+ l2len -= n;
+ }
}
/**
@@ -87,7 +103,7 @@ void pcap(const char *pkt, size_t l2len)
if (clock_gettime(CLOCK_REALTIME, &now))
err_perror("Failed to get CLOCK_REALTIME time");
- pcap_frame(&iov, 1, 0, &now);
+ pcap_frame(&iov, 1, 0, l2len, &now);
}
/**
@@ -110,7 +126,9 @@ void pcap_multiple(const struct iovec *iov, size_t frame_parts, unsigned int n,
err_perror("Failed to get CLOCK_REALTIME time");
for (i = 0; i < n; i++)
- pcap_frame(iov + i * frame_parts, frame_parts, offset, &now);
+ pcap_frame(iov + i * frame_parts, frame_parts, offset,
+ iov_size(iov + i * frame_parts, frame_parts) - offset,
+ &now);
}
/**
@@ -120,8 +138,9 @@ void pcap_multiple(const struct iovec *iov, size_t frame_parts, unsigned int n,
* containing packet data to write, including L2 header
* @iovcnt: Number of buffers (@iov entries)
* @offset: Offset of the L2 frame within the full data length
+ * @l2len: Length of L2 frame data to capture
*/
-void pcap_iov(const struct iovec *iov, size_t iovcnt, size_t offset)
+void pcap_iov(const struct iovec *iov, size_t iovcnt, size_t offset, size_t l2len)
{
struct timespec now = { 0 };
@@ -131,7 +150,7 @@ void pcap_iov(const struct iovec *iov, size_t iovcnt, size_t offset)
if (clock_gettime(CLOCK_REALTIME, &now))
err_perror("Failed to get CLOCK_REALTIME time");
- pcap_frame(iov, iovcnt, offset, &now);
+ pcap_frame(iov, iovcnt, offset, l2len, &now);
}
/**
diff --git a/pcap.h b/pcap.h
index dface5df4ee6..c171257cbd73 100644
--- a/pcap.h
+++ b/pcap.h
@@ -13,7 +13,7 @@ extern int pcap_fd;
void pcap(const char *pkt, size_t l2len);
void pcap_multiple(const struct iovec *iov, size_t frame_parts, unsigned int n,
size_t offset);
-void pcap_iov(const struct iovec *iov, size_t iovcnt, size_t offset);
+void pcap_iov(const struct iovec *iov, size_t iovcnt, size_t offset, size_t l2len);
void pcap_init(struct ctx *c);
#endif /* PCAP_H */
diff --git a/tap.c b/tap.c
index b61199dd699d..007c91864b4e 100644
--- a/tap.c
+++ b/tap.c
@@ -1105,7 +1105,7 @@ void tap_add_packet(struct ctx *c, struct iov_tail *data,
struct ethhdr eh_storage;
const struct ethhdr *eh;
- pcap_iov(data->iov, data->cnt, data->off);
+ pcap_iov(data->iov, data->cnt, data->off, iov_tail_size(data));
eh = IOV_PEEK_HEADER(data, eh_storage);
if (!eh)
diff --git a/tcp_vu.c b/tcp_vu.c
index 0cd01190d612..329fa969fca1 100644
--- a/tcp_vu.c
+++ b/tcp_vu.c
@@ -143,7 +143,8 @@ int tcp_vu_send_flag(const struct ctx *c, struct tcp_tap_conn *conn, int flags)
vu_flush(vdev, vq, flags_elem, 1);
if (*c->pcap)
- pcap_iov(&flags_elem[0].in_sg[0], 1, VNET_HLEN);
+ pcap_iov(&flags_elem[0].in_sg[0], 1, VNET_HLEN,
+ hdrlen + optlen - VNET_HLEN);
if (flags & DUP_ACK) {
elem_cnt = vu_collect(vdev, vq, &flags_elem[1], 1,
@@ -159,7 +160,8 @@ int tcp_vu_send_flag(const struct ctx *c, struct tcp_tap_conn *conn, int flags)
vu_flush(vdev, vq, &flags_elem[1], 1);
if (*c->pcap)
- pcap_iov(&flags_elem[1].in_sg[0], 1, VNET_HLEN);
+ pcap_iov(&flags_elem[1].in_sg[0], 1, VNET_HLEN,
+ hdrlen + optlen - VNET_HLEN);
}
}
vu_queue_notify(vdev, vq);
@@ -464,7 +466,8 @@ int tcp_vu_data_from_sock(const struct ctx *c, struct tcp_tap_conn *conn)
vu_flush(vdev, vq, &elem[head[i]], buf_cnt);
if (*c->pcap)
- pcap_iov(iov, buf_cnt, VNET_HLEN);
+ pcap_iov(iov, buf_cnt, VNET_HLEN,
+ dlen + hdrlen - VNET_HLEN);
conn->seq_to_tap += dlen;
}
diff --git a/udp_vu.c b/udp_vu.c
index 5421a7d71a19..81491afa7e6a 100644
--- a/udp_vu.c
+++ b/udp_vu.c
@@ -185,6 +185,7 @@ 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];
struct vu_dev *vdev = c->vdev;
struct vu_virtq *vq = &vdev->vq[VHOST_USER_RX_QUEUE];
+ size_t hdrlen = udp_vu_hdrlen(v6);
int i;
assert(!c->no_udp);
@@ -230,7 +231,8 @@ void udp_vu_sock_to_tap(const struct ctx *c, int s, int n, flow_sidx_t tosidx)
size_t l4len = udp_vu_prepare(c, iov_vu, toside, dlen);
if (*c->pcap) {
udp_vu_csum(toside, iov_vu, iov_cnt, l4len);
- pcap_iov(iov_vu, iov_cnt, VNET_HLEN);
+ pcap_iov(iov_vu, iov_cnt, VNET_HLEN,
+ hdrlen + dlen - VNET_HLEN);
}
vu_flush(vdev, vq, elem, elem_used);
vu_queue_notify(vdev, vq);
diff --git a/vu_common.c b/vu_common.c
index 57949ca32309..f254cb67ec78 100644
--- a/vu_common.c
+++ b/vu_common.c
@@ -268,7 +268,7 @@ int vu_send_single(const struct ctx *c, const void *buf, size_t size)
iov_from_buf(in_sg, in_total, VNET_HLEN, buf, total);
if (*c->pcap)
- pcap_iov(in_sg, in_total, VNET_HLEN);
+ pcap_iov(in_sg, in_total, VNET_HLEN, size);
vu_flush(vdev, vq, elem, elem_cnt);
vu_queue_notify(vdev, vq);
--
2.53.0