From d565082f84134cc22814bf959b8491e92353ab0b Mon Sep 17 00:00:00 2001 From: Stefano Brivio Date: Tue, 5 Oct 2021 19:51:03 +0200 Subject: [PATCH] tcp: Simplify ACK-sending conditions in tcp_data_from_tap() Now that we have a proper function checking when and how to send ACKs and window updates, we don't need to duplicate this logic in tcp_data_from_tap(). Signed-off-by: Stefano Brivio --- tcp.c | 29 +++++++++-------------------- 1 file changed, 9 insertions(+), 20 deletions(-) diff --git a/tcp.c b/tcp.c index fba118b..6752a59 100644 --- a/tcp.c +++ b/tcp.c @@ -2324,7 +2324,7 @@ static void tcp_data_from_tap(struct ctx *c, struct tcp_tap_conn *conn, struct tap_l4_msg *msg, int count, struct timespec *now) { - int i, iov_i, ack = 0, fin = 0, psh = 0, retr = 0, keep = -1; + int i, iov_i, ack = 0, fin = 0, retr = 0, keep = -1; struct msghdr mh = { .msg_iov = tcp_tap_iov }; uint32_t max_ack_seq = conn->seq_ack_from_tap; uint16_t max_ack_seq_wnd = conn->wnd_from_tap; @@ -2382,9 +2382,6 @@ static void tcp_data_from_tap(struct ctx *c, struct tcp_tap_conn *conn, if (th->fin) fin = 1; - if (th->psh) - psh = 1; - if (!len) continue; @@ -2411,11 +2408,8 @@ static void tcp_data_from_tap(struct ctx *c, struct tcp_tap_conn *conn, * ^ seq * (offset < 0) */ - if (SEQ_GE(seq_offset, 0) && SEQ_LE(seq + len, seq_from_tap)) { - /* Force sending ACK, sender might have lost one */ - psh = 1; + if (SEQ_GE(seq_offset, 0) && SEQ_LE(seq + len, seq_from_tap)) continue; - } if (SEQ_LT(seq_offset, 0)) { if (keep == -1) @@ -2469,20 +2463,22 @@ eintr: goto eintr; if (errno == EAGAIN || errno == EWOULDBLOCK) { - tcp_send_to_tap(c, conn, UPDATE_WINDOW, now); + tcp_send_to_tap(c, conn, 0, now); return; } tcp_rst(c, conn); return; } + if (n < (seq_from_tap - conn->seq_from_tap)) { partial_send = 1; - tcp_send_to_tap(c, conn, UPDATE_WINDOW, now); + conn->seq_from_tap += n; + tcp_send_to_tap(c, conn, 0, now); + } else { + conn->seq_from_tap += n; } - conn->seq_from_tap += n; - out: if (keep != -1) { if (conn->seq_dup_ack != conn->seq_from_tap) { @@ -2511,14 +2507,7 @@ out: tcp_send_to_tap(c, conn, ACK, now); } } else { - int ack_to_tap = timespec_diff_ms(now, &conn->ts_ack_to_tap); - int ack_offset = conn->seq_from_tap - conn->seq_ack_to_tap; - - if (c->mode == MODE_PASTA || - psh || SEQ_GE(ack_offset, conn->wnd_to_tap * 2 / 3) || - ack_to_tap > ACK_INTERVAL) { - tcp_send_to_tap(c, conn, psh ? FORCE_ACK : 0, now); - } + tcp_send_to_tap(c, conn, 0, now); } }