tcp: Fast re-transmit, more fixes for closing states and no_snd_wnd
...and while at it, fix an issue in the calculation of the last IOV buffer size: if we can't receive enough data to fill up the window, the last buffer can be filled completely. Also streamline the code setting iovec lengths if cached values are not matching. Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
This commit is contained in:
Stefano Brivio
parent
0017bc3c3e
commit
539dcf5add
1 changed files with 73 additions and 45 deletions
94
tcp.c
94
tcp.c
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@ -1545,12 +1545,16 @@ static int tcp_data_from_sock(struct ctx *c, struct tcp_tap_conn *conn,
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already_sent = conn->seq_to_tap - conn->seq_ack_from_tap;
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if (!conn->tap_window || already_sent >= conn->tap_window)
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return 1;
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return 0;
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fill_bufs = DIV_ROUND_UP(conn->tap_window - already_sent,
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conn->mss_guest);
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if (fill_bufs > TCP_TAP_FRAMES)
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if (fill_bufs > TCP_TAP_FRAMES) {
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fill_bufs = TCP_TAP_FRAMES;
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iov_rem = 0;
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} else {
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iov_rem = (conn->tap_window - already_sent) % conn->mss_guest;
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}
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/* Adjust iovec length for recvmsg() based on what was set last time. */
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if (v4) {
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@ -1562,21 +1566,16 @@ static int tcp_data_from_sock(struct ctx *c, struct tcp_tap_conn *conn,
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buf_mss = &tcp6_l2_buf_mss;
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buf_mss_nr_set = &tcp6_l2_buf_mss_nr_set;
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}
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if (*buf_mss != conn->mss_guest) {
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for (i = 0; i < fill_bufs; i++)
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if (*buf_mss != conn->mss_guest)
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*buf_mss_nr_set = 0;
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for (i = *buf_mss_nr_set; i < fill_bufs; i++)
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iov[i].iov_len = conn->mss_guest;
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*buf_mss = conn->mss_guest;
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*buf_mss_nr_set = fill_bufs - 1;
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} else if (*buf_mss_nr_set < fill_bufs) {
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for (i = *buf_mss_nr_set; i < fill_bufs; i++)
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iov[i].iov_len = conn->mss_guest;
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*buf_mss_nr_set = fill_bufs - 1;
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}
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/* First buffer is to discard data, last one may be partially filled. */
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iov[-1].iov_len = already_sent;
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iov_rem = (conn->tap_window - already_sent) % conn->mss_guest;
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if (iov_rem && fill_bufs < TCP_TAP_FRAMES)
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if (iov_rem)
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iov[fill_bufs - 1].iov_len = iov_rem;
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if (v4)
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tcp4_l2_mh_sock.msg_iovlen = fill_bufs + 1;
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@ -1616,27 +1615,28 @@ static int tcp_data_from_sock(struct ctx *c, struct tcp_tap_conn *conn,
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buf_mss_tap = &tcp6_l2_buf_mss_tap;
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buf_mss_tap_nr_set = &tcp6_l2_buf_mss_tap_nr_set;
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}
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if (*buf_mss_tap != mss_tap) {
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for (i = 0; i < send_bufs; i++)
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if (*buf_mss_tap != mss_tap)
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*buf_mss_tap_nr_set = 0;
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for (i = *buf_mss_tap_nr_set; i < send_bufs; i++)
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iov_tap[i].iov_len = mss_tap;
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*buf_mss_tap = mss_tap;
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*buf_mss_tap_nr_set = send_bufs;
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} else if (*buf_mss_tap_nr_set < send_bufs) {
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for (i = *buf_mss_tap_nr_set; i < send_bufs; i++)
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iov_tap[i].iov_len = mss_tap;
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*buf_mss_tap_nr_set = send_bufs;
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}
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iov_tap[send_bufs - 1].iov_len = mss_tap - conn->mss_guest + last_len;
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/* Likely, some new data was acked too. */
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if (conn->seq_from_tap != conn->seq_ack_to_tap) {
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if (getsockopt(conn->sock, SOL_TCP, TCP_INFO, &info, &sl))
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if (conn->no_snd_wnd) {
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conn->seq_ack_to_tap = conn->seq_from_tap;
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} else {
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if (getsockopt(conn->sock, SOL_TCP, TCP_INFO, &info,
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&sl))
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goto err;
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conn->tcpi_acked_last = info.tcpi_bytes_acked;
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conn->seq_ack_to_tap = info.tcpi_bytes_acked +
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conn->seq_init_from_tap;
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}
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} else {
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info.tcpi_snd_wscale = conn->ws;
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info.tcpi_snd_wnd = conn->tcpi_snd_wnd;
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@ -1776,11 +1776,14 @@ err:
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goto out_restore_iov;
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zero_len:
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if (conn->state >= ESTABLISHED_SOCK_FIN)
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goto out_restore_iov;
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if (conn->state == FIN_WAIT_1) {
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tcp_tap_state(conn, FIN_WAIT_1_SOCK_FIN);
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} else if (conn->state < ESTABLISHED_SOCK_FIN) {
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tcp_tap_state(conn, ESTABLISHED_SOCK_FIN);
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shutdown(conn->sock, SHUT_RD);
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tcp_send_to_tap(c, conn, FIN | ACK, NULL, 0);
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}
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goto out_restore_iov;
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out:
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@ -1807,10 +1810,11 @@ static void tcp_data_from_tap(struct ctx *c, struct tcp_tap_conn *conn,
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struct tap_msg *msg, int count,
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struct timespec *now)
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{
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int i, iov_i, keep = -1, ack = 0, fin = 0, retr = 0;
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struct msghdr mh = { .msg_iov = tcp_tap_iov };
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uint32_t max_ack_seq = conn->seq_ack_from_tap;
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uint32_t seq_from_tap = conn->seq_from_tap;
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int i, iov_i, keep = -1, ack = 0, fin = 0;
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uint16_t max_ack_seq_wnd;
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ssize_t len;
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for (i = 0, iov_i = 0; i < count; i++) {
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@ -1840,17 +1844,33 @@ static void tcp_data_from_tap(struct ctx *c, struct tcp_tap_conn *conn,
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seq = ntohl(th->seq);
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ack_seq = ntohl(th->ack_seq);
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if (!i) {
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if (count == 1)
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max_ack_seq_wnd = ntohs(th->window);
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else
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max_ack_seq_wnd = ntohs(th->window) - 1;
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}
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if (th->ack) {
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ack = 1;
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if (ack_seq - conn->seq_ack_from_tap < MAX_WINDOW &&
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ack_seq - max_ack_seq < MAX_WINDOW)
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ack_seq - max_ack_seq < MAX_WINDOW) {
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/* Fast re-transmit */
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retr = !len && ack_seq == max_ack_seq &&
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max_ack_seq_wnd == ntohs(th->window);
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max_ack_seq_wnd = ntohs(th->window);
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max_ack_seq = ack_seq;
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}
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}
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if (th->fin)
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fin = 1;
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if (!len)
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continue;
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seq_offset = seq_from_tap - seq;
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/* Use data from this buffer only in these two cases:
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*
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@ -1858,7 +1878,6 @@ static void tcp_data_from_tap(struct ctx *c, struct tcp_tap_conn *conn,
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* |--------| <-- len |--------| <-- len
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* '----' <-- offset ' <-- offset
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* ^ seq ^ seq
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*
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* (offset >= 0, seq + len > seq_from_tap)
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*
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* discard in these two cases:
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@ -1900,6 +1919,11 @@ static void tcp_data_from_tap(struct ctx *c, struct tcp_tap_conn *conn,
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tcp_sock_consume(conn, max_ack_seq);
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}
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if (retr) {
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conn->seq_to_tap = max_ack_seq;
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tcp_data_from_sock(c, conn, now);
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}
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if (!iov_i) {
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if (keep != -1) {
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tcp_send_to_tap(c, conn, ACK, NULL, 0);
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@ -1926,6 +1950,7 @@ static void tcp_data_from_tap(struct ctx *c, struct tcp_tap_conn *conn,
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}
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conn->seq_from_tap += len;
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if (!fin)
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tcp_send_to_tap(c, conn, 0, NULL, 0);
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fin:
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@ -1935,11 +1960,12 @@ fin:
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if (fin) {
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shutdown(conn->sock, SHUT_WR);
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if (conn->state == ESTABLISHED)
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if (conn->state == ESTABLISHED) {
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tcp_tap_state(conn, FIN_WAIT_1);
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else
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tcp_data_from_sock(c, conn, now);
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} else {
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tcp_tap_state(conn, LAST_ACK);
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return;
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}
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}
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}
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@ -2023,12 +2049,12 @@ int tcp_tap_handler(struct ctx *c, int af, void *addr,
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conn->seq_ack_to_tap = conn->seq_from_tap;
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tcp_tap_state(conn, ESTABLISHED);
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tcp_send_to_tap(c, conn, ACK, NULL, 0);
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/* The client might have sent data already, which we didn't
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* dequeue waiting for SYN,ACK from tap -- check now.
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*/
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tcp_data_from_sock(c, conn, now);
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tcp_send_to_tap(c, conn, 0, NULL, 0);
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ev.events = EPOLLIN | EPOLLET | EPOLLRDHUP;
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ref.s = conn->sock;
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@ -2055,11 +2081,13 @@ int tcp_tap_handler(struct ctx *c, int af, void *addr,
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case CLOSE_WAIT:
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tcp_data_from_tap(c, conn, msg, count, now);
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return count;
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case FIN_WAIT_1:
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tcp_send_to_tap(c, conn, ACK, NULL, 0);
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break;
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case FIN_WAIT_1_SOCK_FIN:
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if (th->ack)
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tcp_tap_destroy(c, conn);
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break;
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case FIN_WAIT_1:
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case TAP_SYN_SENT:
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case LAST_ACK:
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case SPLICE_ACCEPTED:
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@ -2570,9 +2598,9 @@ void tcp_sock_handler(struct ctx *c, union epoll_ref ref, uint32_t events,
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tcp_tap_state(conn, FIN_WAIT_1_SOCK_FIN);
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shutdown(conn->sock, SHUT_RD);
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tcp_data_from_sock(c, conn, now);
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tcp_send_to_tap(c, conn, FIN | ACK, NULL, 0);
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tcp_sock_consume(conn, conn->seq_ack_from_tap);
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} else {
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tcp_send_to_tap(c, conn, FIN | ACK, NULL, 0);
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} else if (conn->state != ESTABLISHED_SOCK_FIN) {
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tcp_tap_destroy(c, conn);
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}
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}
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@ -2731,7 +2759,7 @@ static void tcp_timer_one(struct ctx *c, struct tcp_tap_conn *conn,
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if (sock_ms > ACK_INTERVAL) {
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if (conn->seq_from_tap > conn->seq_ack_to_tap)
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tcp_send_to_tap(c, conn, ACK, NULL, 0);
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tcp_send_to_tap(c, conn, 0, NULL, 0);
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}
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if (ack_tap_ms > ACK_TIMEOUT) {
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