On Mon, Sep 16, 2024 at 02:16:01PM +0200, Laurent Vivier wrote: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>--- tcp.c | 24 +++++++++++++++++------- tcp_buf.c | 8 +++++--- tcp_internal.h | 3 ++- 3 files changed, 24 insertions(+), 11 deletions(-) diff --git a/tcp.c b/tcp.c index f9fe1b9a1330..a44d7b977214 100644 --- a/tcp.c +++ b/tcp.c @@ -903,6 +903,7 @@ static void tcp_fill_header(struct tcphdr *th, * @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)); @@ -945,13 +949,14 @@ static size_t tcp_fill_headers4(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: 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,-- David Gibson (he or they) | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you, not the other way | around. http://www.ozlabs.org/~dgibson