diff options
| -rw-r--r-- | tcp.c | 78 |
1 files changed, 54 insertions, 24 deletions
@@ -1567,24 +1567,25 @@ static void tcp_update_seqack_from_tap(const struct ctx *c, } /** - * tcp_send_flag() - Send segment with flags to tap (no payload) + * tcp_prepare_flags() - 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 (output parameter) * - * 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_prepare_flags(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) @@ -1606,20 +1607,12 @@ 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; - + *optlen = 0; 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; @@ -1653,17 +1646,13 @@ 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); - l4len = tcp_l2_buf_fill_headers(c, conn, iov, optlen, NULL, - 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); @@ -1678,6 +1667,47 @@ 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; +} + +/** + * tcp_send_flag() - Send segment with flags to tap (no payload) + * @c: Execution context + * @conn: Connection pointer + * @flags: TCP flags: if not set, send segment only if ACK is due + * + * Return: negative error code on connection reset, 0 otherwise + */ +static int tcp_send_flag(struct ctx *c, struct tcp_tap_conn *conn, int flags) +{ + struct tcp_flags_t *payload; + struct iovec *iov; + size_t optlen; + size_t l4len; + uint32_t seq; + int ret; + + 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; + + seq = conn->seq_to_tap; + ret = tcp_prepare_flags(c, conn, flags, &payload->th, + payload->opts, &optlen); + if (ret <= 0) { + if (CONN_V4(conn)) + tcp4_flags_used--; + else + tcp6_flags_used--; + return ret; + } + + l4len = tcp_l2_buf_fill_headers(c, conn, iov, optlen, NULL, seq); + iov[TCP_IOV_PAYLOAD].iov_len = l4len; + if (flags & DUP_ACK) { struct iovec *dup_iov; int i; |