157 lines
4.8 KiB
C
157 lines
4.8 KiB
C
/* Copyright (c) 2017 - 2022 LiteSpeed Technologies Inc. See LICENSE. */
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#include <inttypes.h>
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#include <stdint.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/queue.h>
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#include "lsquic.h"
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#include "lsquic_int_types.h"
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#include "lsquic_conn_flow.h"
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#include "lsquic_types.h"
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#include "lsquic_rtt.h"
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#include "lsquic_varint.h"
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#include "lsquic_sfcw.h"
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#include "lsquic_hq.h"
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#include "lsquic_hash.h"
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#include "lsquic_stream.h"
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#include "lsquic_conn_public.h"
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#include "lsquic_mm.h"
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#include "lsquic_engine_public.h"
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#include "lsquic_util.h"
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#include "lsquic_conn.h"
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#include "lsquic_ev_log.h"
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#define LSQUIC_LOGGER_MODULE LSQLM_SFCW
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#define LSQUIC_LOG_CONN_ID lsquic_conn_log_cid(fc->sf_conn_pub->lconn)
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#define LSQUIC_LOG_STREAM_ID fc->sf_stream_id
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#include "lsquic_logger.h"
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void
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lsquic_sfcw_init (struct lsquic_sfcw *fc, unsigned max_recv_window,
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struct lsquic_cfcw *cfcw, struct lsquic_conn_public *cpub,
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lsquic_stream_id_t stream_id)
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{
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memset(fc, 0, sizeof(*fc));
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fc->sf_max_recv_win = max_recv_window;
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fc->sf_cfcw = cfcw;
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fc->sf_conn_pub = cpub;
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fc->sf_stream_id = stream_id;
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(void) lsquic_sfcw_fc_offsets_changed(fc);
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}
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static void
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sfcw_maybe_increase_max_window (struct lsquic_sfcw *fc)
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{
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unsigned new_max_window, max_conn_window;
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new_max_window = fc->sf_max_recv_win * 2;
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/* Do not increase past explicitly specified maximum */
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if (new_max_window > fc->sf_conn_pub->enpub->enp_settings.es_max_sfcw)
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new_max_window = fc->sf_conn_pub->enpub->enp_settings.es_max_sfcw;
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if (fc->sf_cfcw)
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{
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/* Do not increase past the connection's maximum window size. The
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* connection's window will be increased separately, if possible.
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*
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* The reference implementation has the logic backwards: Imagine
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* several concurrent streams that are not being read from fast
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* enough by the user code. Each of them uses only a fraction
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* of bandwidth. Does it mean that the connection window must
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* increase? No.
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*/
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max_conn_window = lsquic_cfcw_get_max_recv_window(fc->sf_cfcw);
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if (new_max_window > max_conn_window)
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new_max_window = max_conn_window;
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}
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else
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{
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/* This means that this stream is not affected by connection flow
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* controller. No need to adjust under connection window.
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*/
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}
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if (new_max_window > fc->sf_max_recv_win)
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{
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LSQ_DEBUG("max window increase %u -> %u",
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fc->sf_max_recv_win, new_max_window);
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EV_LOG_CONN_EVENT(LSQUIC_LOG_CONN_ID,
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"max SFCW increase %u -> %u", fc->sf_max_recv_win,
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new_max_window);
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fc->sf_max_recv_win = new_max_window;
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}
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else
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LSQ_DEBUG("max window could use an increase, but we're stuck "
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"at %u", fc->sf_max_recv_win);
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}
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int
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lsquic_sfcw_fc_offsets_changed (struct lsquic_sfcw *fc)
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{
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lsquic_time_t since_last_update, srtt, now;
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if (fc->sf_recv_off - fc->sf_read_off >= fc->sf_max_recv_win / 2)
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{
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LSQ_DEBUG("recv_off has not changed, still at %"PRIu64,
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fc->sf_recv_off);
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return 0;
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}
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now = lsquic_time_now();
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since_last_update = now - fc->sf_last_updated;
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fc->sf_last_updated = now;
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srtt = lsquic_rtt_stats_get_srtt(&fc->sf_conn_pub->rtt_stats);
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if (since_last_update < srtt * 2)
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sfcw_maybe_increase_max_window(fc);
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fc->sf_recv_off = fc->sf_read_off + fc->sf_max_recv_win;
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LSQ_DEBUG("recv_off changed: read_off: %"PRIu64"; "
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"recv_off: %"PRIu64, fc->sf_read_off, fc->sf_recv_off);
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return 1;
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}
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int
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lsquic_sfcw_set_max_recv_off (struct lsquic_sfcw *fc, uint64_t max_recv_off)
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{
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if (max_recv_off <= fc->sf_recv_off)
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{
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if (!fc->sf_cfcw || lsquic_cfcw_incr_max_recv_off(fc->sf_cfcw,
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max_recv_off - fc->sf_max_recv_off))
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{
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LSQ_DEBUG("max_recv_off goes from %"PRIu64" to %"PRIu64,
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fc->sf_max_recv_off, max_recv_off);
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fc->sf_max_recv_off = max_recv_off;
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return 1;
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}
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else
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{
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/* cfcw prints its own warning */
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return 0;
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}
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}
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else
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{
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LSQ_INFO("flow control violation: received at offset %"PRIu64", "
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"while flow control receive offset is %"PRIu64,
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max_recv_off, fc->sf_recv_off);
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return 0;
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}
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}
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void
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lsquic_sfcw_set_read_off (struct lsquic_sfcw *fc, uint64_t off)
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{
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if (fc->sf_cfcw)
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lsquic_cfcw_incr_read_off(fc->sf_cfcw, off - fc->sf_read_off);
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LSQ_DEBUG("read_off goes from %"PRIu64" to %"PRIu64,
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fc->sf_read_off, off);
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fc->sf_read_off = off;
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}
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