Signed-off-by: Laurent Vivier <lvivier(a)redhat.com>
---
tcp.c | 87 ++++++++++++++++++++++++++++++++++++-----------------------
1 file changed, 54 insertions(+), 33 deletions(-)
diff --git a/tcp.c b/tcp.c
index 6f221995f3bc..a6f43010f58f 100644
--- a/tcp.c
+++ b/tcp.c
@@ -1518,24 +1518,25 @@ static void tcp_update_seqack_from_tap(const struct ctx *c,
}
/**
- * tcp_send_flag() - Send segment with flags to tap (no payload)
+ * tcp_fill_flag_header() - Prepare header for flags-only segment (no payload)
* @c: Execution context
* @conn: Connection pointer
* @flags: TCP flags: if not set, send segment only if ACK is due
+ * @th: TCP header to update
+ * @data: buffer to store TCP option
+ * @optlen: size of the TCP option buffer
*
- * Return: negative error code on connection reset, 0 otherwise
+ * Return: < 0 error code on connection reset,
+ * 0 if there is no flag to send
+ * 1 otherwise
*/
-static int tcp_send_flag(struct ctx *c, struct tcp_tap_conn *conn, int flags)
+static int tcp_fill_flag_header(struct ctx *c, struct tcp_tap_conn *conn,
+ int flags, struct tcphdr *th, char *data,
+ size_t *optlen)
{
- struct tcp_flags_t *payload;
struct tcp_info tinfo = { 0 };
socklen_t sl = sizeof(tinfo);
int s = conn->sock;
- size_t optlen = 0;
- struct tcphdr *th;
- struct iovec *iov;
- size_t l4len;
- char *data;
if (SEQ_GE(conn->seq_ack_to_tap, conn->seq_from_tap) &&
!flags && conn->wnd_to_tap)
@@ -1557,20 +1558,11 @@ static int tcp_send_flag(struct ctx *c, struct tcp_tap_conn *conn,
int flags)
if (!tcp_update_seqack_wnd(c, conn, flags, &tinfo) && !flags)
return 0;
- if (CONN_V4(conn))
- iov = tcp4_l2_flags_iov[tcp4_flags_used++];
- else
- iov = tcp6_l2_flags_iov[tcp6_flags_used++];
-
- payload = iov[TCP_IOV_PAYLOAD].iov_base;
- th = &payload->th;
- data = payload->opts;
-
if (flags & SYN) {
int mss;
/* Options: MSS, NOP and window scale (8 bytes) */
- optlen = OPT_MSS_LEN + 1 + OPT_WS_LEN;
+ *optlen = OPT_MSS_LEN + 1 + OPT_WS_LEN;
*data++ = OPT_MSS;
*data++ = OPT_MSS_LEN;
@@ -1604,26 +1596,13 @@ static int tcp_send_flag(struct ctx *c, struct tcp_tap_conn *conn,
int flags)
flags |= ACK;
}
- th->doff = (sizeof(*th) + optlen) / 4;
+ th->doff = (sizeof(*th) + *optlen) / 4;
th->ack = !!(flags & ACK);
th->rst = !!(flags & RST);
th->syn = !!(flags & SYN);
th->fin = !!(flags & FIN);
- if (CONN_V4(conn)) {
- l4len = tcp_fill_headers4(c, conn, iov[TCP_IOV_TAP].iov_base,
- iov[TCP_IOV_IP].iov_base,
- iov[TCP_IOV_PAYLOAD].iov_base, optlen,
- NULL, conn->seq_to_tap);
- } else {
- l4len = tcp_fill_headers6(c, conn, iov[TCP_IOV_TAP].iov_base,
- iov[TCP_IOV_IP].iov_base,
- iov[TCP_IOV_PAYLOAD].iov_base, optlen,
- conn->seq_to_tap);
- }
- iov[TCP_IOV_PAYLOAD].iov_len = l4len;
-
if (th->ack) {
if (SEQ_GE(conn->seq_ack_to_tap, conn->seq_from_tap))
conn_flag(c, conn, ~ACK_TO_TAP_DUE);
@@ -1638,6 +1617,48 @@ static int tcp_send_flag(struct ctx *c, struct tcp_tap_conn *conn,
int flags)
if (th->fin || th->syn)
conn->seq_to_tap++;
+ return 1;
+}
+
+static int tcp_send_flag(struct ctx *c, struct tcp_tap_conn *conn, int flags)
+{
+ struct tcp_flags_t *payload;
+ size_t optlen = 0;
+ struct iovec *iov;
+ size_t l4len;
+ int ret;
+
+ if (CONN_V4(conn)) {
+ iov = tcp4_l2_flags_iov[tcp4_flags_used++];
+
+ payload = iov[TCP_IOV_PAYLOAD].iov_base;
+
+ ret = tcp_fill_flag_header(c, conn, flags, &payload->th,
+ payload->opts, &optlen);
+ if (ret <= 0)
+ return ret;
+
+ l4len = tcp_fill_headers4(c, conn, iov[TCP_IOV_TAP].iov_base,
+ iov[TCP_IOV_IP].iov_base,
+ iov[TCP_IOV_PAYLOAD].iov_base, optlen,
+ NULL, conn->seq_to_tap);
+ } else {
+ iov = tcp6_l2_flags_iov[tcp6_flags_used++];
+
+ payload = iov[TCP_IOV_PAYLOAD].iov_base;
+
+ ret = tcp_fill_flag_header(c, conn, flags, &payload->th,
+ payload->opts, &optlen);
+ if (ret <= 0)
+ return ret;
+
+ l4len = tcp_fill_headers6(c, conn, iov[TCP_IOV_TAP].iov_base,
+ iov[TCP_IOV_IP].iov_base,
+ iov[TCP_IOV_PAYLOAD].iov_base, optlen,
+ conn->seq_to_tap);
+ }
+ iov[TCP_IOV_PAYLOAD].iov_len = l4len;
+
if (flags & DUP_ACK) {
struct iovec *dup_iov;
int i;
--
2.44.0