We can need not to set TCP checksum. Add a parameter to
tcp_fill_headers4() and tcp_fill_headers6() to disable it.
Signed-off-by: Laurent Vivier <lvivier(a)redhat.com>
Reviewed-by: David Gibson <david(a)gibson.dropbear.id.au>
---
Notes:
v3: align parameters description with tab
tcp.c | 52 ++++++++++++++++++++++++++++++--------------------
tcp_buf.c | 8 +++++---
tcp_internal.h | 3 ++-
3 files changed, 38 insertions(+), 25 deletions(-)
diff --git a/tcp.c b/tcp.c
index f9fe1b9a1330..7307ea74f25c 100644
--- a/tcp.c
+++ b/tcp.c
@@ -896,13 +896,14 @@ static void tcp_fill_header(struct tcphdr *th,
/**
* tcp_fill_headers4() - Fill 802.3, IPv4, TCP headers in pre-cooked buffers
- * @conn: Connection pointer
- * @taph: tap backend specific header
- * @iph: Pointer to IPv4 header
- * @th: Pointer to TCP header
- * @dlen: TCP payload length
- * @check: Checksum, if already known
- * @seq: Sequence number for this segment
+ * @conn: Connection pointer
+ * @taph: tap backend specific header
+ * @iph: Pointer to IPv4 header
+ * @th: Pointer to TCP header
+ * @dlen: TCP payload length
+ * @check: Checksum, if already known
+ * @seq: Sequence number for this segment
+ * @no_tcp_csum: Do not set TCP checksum
*
* Return: The IPv4 payload length, host order
*/
@@ -910,7 +911,7 @@ static size_t tcp_fill_headers4(const struct tcp_tap_conn *conn,
struct tap_hdr *taph,
struct iphdr *iph, struct tcphdr *th,
size_t dlen, const uint16_t *check,
- uint32_t seq)
+ uint32_t seq, bool no_tcp_csum)
{
const struct flowside *tapside = TAPFLOW(conn);
const struct in_addr *src4 = inany_v4(&tapside->oaddr);
@@ -929,7 +930,10 @@ static size_t tcp_fill_headers4(const struct tcp_tap_conn *conn,
tcp_fill_header(th, conn, seq);
- tcp_update_check_tcp4(iph, th);
+ if (no_tcp_csum)
+ th->check = 0;
+ else
+ tcp_update_check_tcp4(iph, th);
tap_hdr_update(taph, l3len + sizeof(struct ethhdr));
@@ -938,20 +942,21 @@ static size_t tcp_fill_headers4(const struct tcp_tap_conn *conn,
/**
* tcp_fill_headers6() - Fill 802.3, IPv6, TCP headers in pre-cooked buffers
- * @conn: Connection pointer
- * @taph: tap backend specific header
- * @ip6h: Pointer to IPv6 header
- * @th: Pointer to TCP header
- * @dlen: TCP payload length
- * @check: Checksum, if already known
- * @seq: Sequence number for this segment
+ * @conn: Connection pointer
+ * @taph: tap backend specific header
+ * @ip6h: Pointer to IPv6 header
+ * @th: Pointer to TCP header
+ * @dlen: TCP payload length
+ * @check: Checksum, if already known
+ * @seq: Sequence number for this segment
+ * @no_tcp_csum: Do not set TCP checksum
*
* Return: The IPv6 payload length, host order
*/
static size_t tcp_fill_headers6(const struct tcp_tap_conn *conn,
struct tap_hdr *taph,
struct ipv6hdr *ip6h, struct tcphdr *th,
- size_t dlen, uint32_t seq)
+ size_t dlen, uint32_t seq, bool no_tcp_csum)
{
const struct flowside *tapside = TAPFLOW(conn);
size_t l4len = dlen + sizeof(*th);
@@ -970,7 +975,10 @@ static size_t tcp_fill_headers6(const struct tcp_tap_conn *conn,
tcp_fill_header(th, conn, seq);
- tcp_update_check_tcp6(ip6h, th);
+ if (no_tcp_csum)
+ th->check = 0;
+ else
+ tcp_update_check_tcp6(ip6h, th);
tap_hdr_update(taph, l4len + sizeof(*ip6h) + sizeof(struct ethhdr));
@@ -984,12 +992,14 @@ static size_t tcp_fill_headers6(const struct tcp_tap_conn *conn,
* @dlen: TCP payload length
* @check: Checksum, if already known
* @seq: Sequence number for this segment
+ * @no_tcp_csum: Do not set TCP checksum
*
* Return: IP payload length, host order
*/
size_t tcp_l2_buf_fill_headers(const struct tcp_tap_conn *conn,
struct iovec *iov, size_t dlen,
- const uint16_t *check, uint32_t seq)
+ const uint16_t *check, uint32_t seq,
+ bool no_tcp_csum)
{
const struct flowside *tapside = TAPFLOW(conn);
const struct in_addr *a4 = inany_v4(&tapside->oaddr);
@@ -998,13 +1008,13 @@ size_t tcp_l2_buf_fill_headers(const struct tcp_tap_conn *conn,
return tcp_fill_headers4(conn, iov[TCP_IOV_TAP].iov_base,
iov[TCP_IOV_IP].iov_base,
iov[TCP_IOV_PAYLOAD].iov_base, dlen,
- check, seq);
+ check, seq, no_tcp_csum);
}
return tcp_fill_headers6(conn, iov[TCP_IOV_TAP].iov_base,
iov[TCP_IOV_IP].iov_base,
iov[TCP_IOV_PAYLOAD].iov_base, dlen,
- seq);
+ seq, no_tcp_csum);
}
/**
diff --git a/tcp_buf.c b/tcp_buf.c
index 1a398461a34b..10a663bdfc26 100644
--- a/tcp_buf.c
+++ b/tcp_buf.c
@@ -320,7 +320,7 @@ int tcp_buf_send_flag(struct ctx *c, struct tcp_tap_conn *conn, int
flags)
return ret;
}
- l4len = tcp_l2_buf_fill_headers(conn, iov, optlen, NULL, seq);
+ l4len = tcp_l2_buf_fill_headers(conn, iov, optlen, NULL, seq, false);
iov[TCP_IOV_PAYLOAD].iov_len = l4len;
if (flags & DUP_ACK) {
@@ -381,7 +381,8 @@ static void tcp_data_to_tap(struct ctx *c, struct tcp_tap_conn *conn,
tcp4_frame_conns[tcp4_payload_used] = conn;
iov = tcp4_l2_iov[tcp4_payload_used++];
- l4len = tcp_l2_buf_fill_headers(conn, iov, dlen, check, seq);
+ l4len = tcp_l2_buf_fill_headers(conn, iov, dlen, check, seq,
+ false);
iov[TCP_IOV_PAYLOAD].iov_len = l4len;
if (tcp4_payload_used > TCP_FRAMES_MEM - 1)
tcp_payload_flush(c);
@@ -389,7 +390,8 @@ static void tcp_data_to_tap(struct ctx *c, struct tcp_tap_conn *conn,
tcp6_frame_conns[tcp6_payload_used] = conn;
iov = tcp6_l2_iov[tcp6_payload_used++];
- l4len = tcp_l2_buf_fill_headers(conn, iov, dlen, NULL, seq);
+ l4len = tcp_l2_buf_fill_headers(conn, iov, dlen, NULL, seq,
+ false);
iov[TCP_IOV_PAYLOAD].iov_len = l4len;
if (tcp6_payload_used > TCP_FRAMES_MEM - 1)
tcp_payload_flush(c);
diff --git a/tcp_internal.h b/tcp_internal.h
index aa8bb64f1f33..e7fe735bfcb4 100644
--- a/tcp_internal.h
+++ b/tcp_internal.h
@@ -91,7 +91,8 @@ void tcp_rst_do(struct ctx *c, struct tcp_tap_conn *conn);
size_t tcp_l2_buf_fill_headers(const struct tcp_tap_conn *conn,
struct iovec *iov, size_t dlen,
- const uint16_t *check, uint32_t seq);
+ const uint16_t *check, uint32_t seq,
+ bool no_tcp_csum);
int tcp_update_seqack_wnd(const struct ctx *c, struct tcp_tap_conn *conn,
int force_seq, struct tcp_info *tinfo);
int tcp_prepare_flags(struct ctx *c, struct tcp_tap_conn *conn, int flags,
--
2.46.0