From 930bc3b0f2d2078747172e960807c84a8cd97495 Mon Sep 17 00:00:00 2001 From: David Gibson Date: Thu, 9 Nov 2023 20:53:59 +1100 Subject: tcp: Rename and small cleanup to tcp_clamp_window() tcp_clamp_window() is _mostly_ about using TCP_WINDOW_CLAMP to control the sock side advertised window, but it is also responsible for actually updating the conn->wnd_from_tap value. Rename to tcp_tap_window_update() to reflect that broader purpose, and pull the logic that's not TCP_WINDOW_CLAMP related out to the front. Signed-off-by: David Gibson Signed-off-by: Stefano Brivio --- tcp.c | 21 ++++++++++----------- 1 file changed, 10 insertions(+), 11 deletions(-) (limited to 'tcp.c') diff --git a/tcp.c b/tcp.c index 19d16a6..13e82ca 100644 --- a/tcp.c +++ b/tcp.c @@ -1789,19 +1789,19 @@ static void tcp_get_tap_ws(struct tcp_tap_conn *conn, } /** - * tcp_clamp_window() - Set new window for connection, clamp on socket + * tcp_tap_window_update() - Process an updated window from tap side * @c: Execution context * @conn: Connection pointer * @window: Window value, host order, unscaled */ -static void tcp_clamp_window(const struct ctx *c, struct tcp_tap_conn *conn, - unsigned wnd) +static void tcp_tap_window_update(const struct ctx *c, + struct tcp_tap_conn *conn, unsigned wnd) { uint32_t prev_scaled = conn->wnd_from_tap << conn->ws_from_tap; int s = conn->sock; - wnd <<= conn->ws_from_tap; - wnd = MIN(MAX_WINDOW, wnd); + wnd = MIN(MAX_WINDOW, wnd << conn->ws_from_tap); + conn->wnd_from_tap = MIN(wnd >> conn->ws_from_tap, USHRT_MAX); /* TODO: With (at least) Linux kernel versions 6.1 to 6.5, if we end up * with a zero-sized window on a TCP socket, dropping data (once @@ -1838,7 +1838,6 @@ static void tcp_clamp_window(const struct ctx *c, struct tcp_tap_conn *conn, return; } - conn->wnd_from_tap = MIN(wnd >> conn->ws_from_tap, USHRT_MAX); if (setsockopt(s, SOL_TCP, TCP_WINDOW_CLAMP, &wnd, sizeof(wnd))) trace("TCP: failed to set TCP_WINDOW_CLAMP on socket %i", s); @@ -2453,7 +2452,7 @@ static int tcp_data_from_tap(struct ctx *c, struct tcp_tap_conn *conn, if (ack && !tcp_sock_consume(conn, max_ack_seq)) tcp_update_seqack_from_tap(c, conn, max_ack_seq); - tcp_clamp_window(c, conn, max_ack_seq_wnd); + tcp_tap_window_update(c, conn, max_ack_seq_wnd); if (retr) { trace("TCP: fast re-transmit, ACK: %u, previous sequence: %u", @@ -2538,7 +2537,7 @@ static void tcp_conn_from_sock_finish(struct ctx *c, struct tcp_tap_conn *conn, const struct tcphdr *th, const char *opts, size_t optlen) { - tcp_clamp_window(c, conn, ntohs(th->window)); + tcp_tap_window_update(c, conn, ntohs(th->window)); tcp_get_tap_ws(conn, opts, optlen); /* First value is not scaled */ @@ -2646,7 +2645,7 @@ int tcp_tap_handler(struct ctx *c, uint8_t pif, int af, if (!th->ack) goto reset; - tcp_clamp_window(c, conn, ntohs(th->window)); + tcp_tap_window_update(c, conn, ntohs(th->window)); tcp_data_from_sock(c, conn); @@ -2670,8 +2669,8 @@ int tcp_tap_handler(struct ctx *c, uint8_t pif, int af, if (count == -1) goto reset; - /* Note: STALLED matters for tcp_clamp_window(): unset it only after - * processing data (and window) from the tap side + /* Note: STALLED matters for tcp_tap_window_update(): unset it only + * after processing data (and window) from the tap side */ conn_flag(c, conn, ~STALLED); -- cgit v1.2.3