[TFRC]: New rx history code
Credit here goes to Gerrit Renker, that provided the initial implementation for this new codebase. I modified it just to try to make it closer to the existing API, renaming some functions, add namespacing and fix one bug where the tfrc_rx_hist_alloc was not freeing the allocated ring entries on the error path. Original changeset comment from Gerrit: ----------- This provides a new, self-contained and generic RX history service for TFRC based protocols. Details: * new data structure, initialisation and cleanup routines; * allocation of dccp_rx_hist entries local to packet_history.c, as a service exported by the dccp_tfrc_lib module. * interface to automatically track highest-received seqno; * receiver-based RTT estimation (needed for instance by RFC 3448, 6.3.1); * a generic function to test for `data packets' as per RFC 4340, sec. 7.7. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
parent
30a0eacd47
commit
b84a2189c4
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@ -641,6 +641,15 @@ static int ccid3_hc_tx_getsockopt(struct sock *sk, const int optname, int len,
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/*
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* Receiver Half-Connection Routines
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*/
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/* CCID3 feedback types */
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enum ccid3_fback_type {
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CCID3_FBACK_NONE = 0,
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CCID3_FBACK_INITIAL,
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CCID3_FBACK_PERIODIC,
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CCID3_FBACK_PARAM_CHANGE
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};
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#ifdef CONFIG_IP_DCCP_CCID3_DEBUG
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static const char *ccid3_rx_state_name(enum ccid3_hc_rx_states state)
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{
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@ -667,59 +676,60 @@ static void ccid3_hc_rx_set_state(struct sock *sk,
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hcrx->ccid3hcrx_state = state;
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}
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static inline void ccid3_hc_rx_update_s(struct ccid3_hc_rx_sock *hcrx, int len)
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{
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if (likely(len > 0)) /* don't update on empty packets (e.g. ACKs) */
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hcrx->ccid3hcrx_s = tfrc_ewma(hcrx->ccid3hcrx_s, len, 9);
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}
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static void ccid3_hc_rx_send_feedback(struct sock *sk)
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static void ccid3_hc_rx_send_feedback(struct sock *sk,
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const struct sk_buff *skb,
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enum ccid3_fback_type fbtype)
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{
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struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
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struct dccp_sock *dp = dccp_sk(sk);
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struct tfrc_rx_hist_entry *packet;
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ktime_t now;
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suseconds_t delta;
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s64 delta = 0;
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ccid3_pr_debug("%s(%p) - entry \n", dccp_role(sk), sk);
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if (unlikely(hcrx->ccid3hcrx_state == TFRC_RSTATE_TERM))
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return;
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now = ktime_get_real();
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switch (hcrx->ccid3hcrx_state) {
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case TFRC_RSTATE_NO_DATA:
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switch (fbtype) {
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case CCID3_FBACK_INITIAL:
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hcrx->ccid3hcrx_x_recv = 0;
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hcrx->ccid3hcrx_pinv = ~0U; /* see RFC 4342, 8.5 */
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break;
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case TFRC_RSTATE_DATA:
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delta = ktime_us_delta(now,
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hcrx->ccid3hcrx_tstamp_last_feedback);
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DCCP_BUG_ON(delta < 0);
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case CCID3_FBACK_PARAM_CHANGE:
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/*
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* When parameters change (new loss or p > p_prev), we do not
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* have a reliable estimate for R_m of [RFC 3448, 6.2] and so
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* need to reuse the previous value of X_recv. However, when
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* X_recv was 0 (due to early loss), this would kill X down to
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* s/t_mbi (i.e. one packet in 64 seconds).
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* To avoid such drastic reduction, we approximate X_recv as
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* the number of bytes since last feedback.
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* This is a safe fallback, since X is bounded above by X_calc.
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*/
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if (hcrx->ccid3hcrx_x_recv > 0)
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break;
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/* fall through */
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case CCID3_FBACK_PERIODIC:
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delta = ktime_us_delta(now, hcrx->ccid3hcrx_tstamp_last_feedback);
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if (delta <= 0)
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DCCP_BUG("delta (%ld) <= 0", (long)delta);
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else
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hcrx->ccid3hcrx_x_recv =
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scaled_div32(hcrx->ccid3hcrx_bytes_recv, delta);
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break;
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case TFRC_RSTATE_TERM:
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DCCP_BUG("%s(%p) - Illegal state TERM", dccp_role(sk), sk);
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default:
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return;
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}
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packet = tfrc_rx_hist_find_data_packet(&hcrx->ccid3hcrx_hist);
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if (unlikely(packet == NULL)) {
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DCCP_WARN("%s(%p), no data packet in history!\n",
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dccp_role(sk), sk);
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return;
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}
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ccid3_pr_debug("Interval %ldusec, X_recv=%u, 1/p=%u\n", (long)delta,
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hcrx->ccid3hcrx_x_recv, hcrx->ccid3hcrx_pinv);
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hcrx->ccid3hcrx_tstamp_last_feedback = now;
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hcrx->ccid3hcrx_ccval_last_counter = packet->tfrchrx_ccval;
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hcrx->ccid3hcrx_last_counter = dccp_hdr(skb)->dccph_ccval;
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hcrx->ccid3hcrx_bytes_recv = 0;
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if (hcrx->ccid3hcrx_p == 0)
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hcrx->ccid3hcrx_pinv = ~0U; /* see RFC 4342, 8.5 */
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else if (hcrx->ccid3hcrx_p > 1000000) {
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DCCP_WARN("p (%u) > 100%%\n", hcrx->ccid3hcrx_p);
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hcrx->ccid3hcrx_pinv = 1; /* use 100% in this case */
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} else
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hcrx->ccid3hcrx_pinv = 1000000 / hcrx->ccid3hcrx_p;
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dp->dccps_hc_rx_insert_options = 1;
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dccp_send_ack(sk);
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}
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@ -750,165 +760,74 @@ static int ccid3_hc_rx_insert_options(struct sock *sk, struct sk_buff *skb)
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return 0;
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}
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static int ccid3_hc_rx_detect_loss(struct sock *sk,
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struct tfrc_rx_hist_entry *packet)
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{
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struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
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struct tfrc_rx_hist_entry *rx_hist =
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tfrc_rx_hist_head(&hcrx->ccid3hcrx_hist);
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u64 seqno = packet->tfrchrx_seqno;
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u64 tmp_seqno;
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int loss = 0;
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u8 ccval;
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tmp_seqno = hcrx->ccid3hcrx_seqno_nonloss;
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if (!rx_hist ||
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follows48(packet->tfrchrx_seqno, hcrx->ccid3hcrx_seqno_nonloss)) {
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hcrx->ccid3hcrx_seqno_nonloss = seqno;
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hcrx->ccid3hcrx_ccval_nonloss = packet->tfrchrx_ccval;
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goto detect_out;
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}
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while (dccp_delta_seqno(hcrx->ccid3hcrx_seqno_nonloss, seqno)
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> TFRC_RECV_NUM_LATE_LOSS) {
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loss = 1;
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dccp_li_update_li(sk,
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&hcrx->ccid3hcrx_li_hist,
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&hcrx->ccid3hcrx_hist,
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hcrx->ccid3hcrx_tstamp_last_feedback,
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hcrx->ccid3hcrx_s,
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hcrx->ccid3hcrx_bytes_recv,
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hcrx->ccid3hcrx_x_recv,
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hcrx->ccid3hcrx_seqno_nonloss,
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hcrx->ccid3hcrx_ccval_nonloss);
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tmp_seqno = hcrx->ccid3hcrx_seqno_nonloss;
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dccp_inc_seqno(&tmp_seqno);
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hcrx->ccid3hcrx_seqno_nonloss = tmp_seqno;
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dccp_inc_seqno(&tmp_seqno);
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while (tfrc_rx_hist_find_entry(&hcrx->ccid3hcrx_hist,
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tmp_seqno, &ccval)) {
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hcrx->ccid3hcrx_seqno_nonloss = tmp_seqno;
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hcrx->ccid3hcrx_ccval_nonloss = ccval;
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dccp_inc_seqno(&tmp_seqno);
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}
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}
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/* FIXME - this code could be simplified with above while */
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/* but works at moment */
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if (follows48(packet->tfrchrx_seqno, hcrx->ccid3hcrx_seqno_nonloss)) {
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hcrx->ccid3hcrx_seqno_nonloss = seqno;
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hcrx->ccid3hcrx_ccval_nonloss = packet->tfrchrx_ccval;
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}
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detect_out:
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tfrc_rx_hist_add_packet(&hcrx->ccid3hcrx_hist,
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&hcrx->ccid3hcrx_li_hist, packet,
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hcrx->ccid3hcrx_seqno_nonloss);
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return loss;
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}
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static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
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{
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struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
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const struct dccp_options_received *opt_recv;
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struct tfrc_rx_hist_entry *packet;
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u32 p_prev, r_sample, rtt_prev;
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int loss, payload_size;
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ktime_t now;
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enum ccid3_fback_type do_feedback = CCID3_FBACK_NONE;
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const u32 ndp = dccp_sk(sk)->dccps_options_received.dccpor_ndp;
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const bool is_data_packet = dccp_data_packet(skb);
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opt_recv = &dccp_sk(sk)->dccps_options_received;
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switch (DCCP_SKB_CB(skb)->dccpd_type) {
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case DCCP_PKT_ACK:
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if (hcrx->ccid3hcrx_state == TFRC_RSTATE_NO_DATA)
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return;
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case DCCP_PKT_DATAACK:
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if (opt_recv->dccpor_timestamp_echo == 0)
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break;
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r_sample = dccp_timestamp() - opt_recv->dccpor_timestamp_echo;
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rtt_prev = hcrx->ccid3hcrx_rtt;
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r_sample = dccp_sample_rtt(sk, 10 * r_sample);
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if (hcrx->ccid3hcrx_state == TFRC_RSTATE_NO_DATA)
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hcrx->ccid3hcrx_rtt = r_sample;
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else
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hcrx->ccid3hcrx_rtt = (hcrx->ccid3hcrx_rtt * 9) / 10 +
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r_sample / 10;
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if (rtt_prev != hcrx->ccid3hcrx_rtt)
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ccid3_pr_debug("%s(%p), New RTT=%uus, elapsed time=%u\n",
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dccp_role(sk), sk, hcrx->ccid3hcrx_rtt,
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opt_recv->dccpor_elapsed_time);
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break;
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case DCCP_PKT_DATA:
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break;
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default: /* We're not interested in other packet types, move along */
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return;
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}
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packet = tfrc_rx_hist_entry_new(opt_recv->dccpor_ndp, skb, GFP_ATOMIC);
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if (unlikely(packet == NULL)) {
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DCCP_WARN("%s(%p), Not enough mem to add rx packet "
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"to history, consider it lost!\n", dccp_role(sk), sk);
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return;
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}
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loss = ccid3_hc_rx_detect_loss(sk, packet);
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if (DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK)
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return;
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payload_size = skb->len - dccp_hdr(skb)->dccph_doff * 4;
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ccid3_hc_rx_update_s(hcrx, payload_size);
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switch (hcrx->ccid3hcrx_state) {
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case TFRC_RSTATE_NO_DATA:
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ccid3_pr_debug("%s(%p, state=%s), skb=%p, sending initial "
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"feedback\n", dccp_role(sk), sk,
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dccp_state_name(sk->sk_state), skb);
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ccid3_hc_rx_send_feedback(sk);
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if (unlikely(hcrx->ccid3hcrx_state == TFRC_RSTATE_NO_DATA)) {
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if (is_data_packet) {
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const u32 payload = skb->len - dccp_hdr(skb)->dccph_doff * 4;
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do_feedback = CCID3_FBACK_INITIAL;
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ccid3_hc_rx_set_state(sk, TFRC_RSTATE_DATA);
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return;
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case TFRC_RSTATE_DATA:
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hcrx->ccid3hcrx_bytes_recv += payload_size;
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if (loss)
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break;
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now = ktime_get_real();
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if ((ktime_us_delta(now, hcrx->ccid3hcrx_tstamp_last_ack) -
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(s64)hcrx->ccid3hcrx_rtt) >= 0) {
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hcrx->ccid3hcrx_tstamp_last_ack = now;
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ccid3_hc_rx_send_feedback(sk);
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hcrx->ccid3hcrx_s = payload;
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/*
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* Not necessary to update ccid3hcrx_bytes_recv here,
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* since X_recv = 0 for the first feedback packet (cf.
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* RFC 3448, 6.3) -- gerrit
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*/
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}
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return;
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case TFRC_RSTATE_TERM:
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DCCP_BUG("%s(%p) - Illegal state TERM", dccp_role(sk), sk);
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return;
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goto update_records;
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}
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/* Dealing with packet loss */
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ccid3_pr_debug("%s(%p, state=%s), data loss! Reacting...\n",
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dccp_role(sk), sk, dccp_state_name(sk->sk_state));
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if (tfrc_rx_hist_duplicate(&hcrx->ccid3hcrx_hist, skb))
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return; /* done receiving */
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p_prev = hcrx->ccid3hcrx_p;
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/* Calculate loss event rate */
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if (!list_empty(&hcrx->ccid3hcrx_li_hist)) {
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u32 i_mean = dccp_li_hist_calc_i_mean(&hcrx->ccid3hcrx_li_hist);
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/* Scaling up by 1000000 as fixed decimal */
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if (i_mean != 0)
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hcrx->ccid3hcrx_p = 1000000 / i_mean;
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} else
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DCCP_BUG("empty loss history");
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if (hcrx->ccid3hcrx_p > p_prev) {
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ccid3_hc_rx_send_feedback(sk);
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return;
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if (is_data_packet) {
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const u32 payload = skb->len - dccp_hdr(skb)->dccph_doff * 4;
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/*
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* Update moving-average of s and the sum of received payload bytes
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*/
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hcrx->ccid3hcrx_s = tfrc_ewma(hcrx->ccid3hcrx_s, payload, 9);
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hcrx->ccid3hcrx_bytes_recv += payload;
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}
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/*
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* Handle pending losses and otherwise check for new loss
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*/
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if (tfrc_rx_hist_new_loss_indicated(&hcrx->ccid3hcrx_hist, skb, ndp))
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goto update_records;
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/*
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* Handle data packets: RTT sampling and monitoring p
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*/
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if (unlikely(!is_data_packet))
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goto update_records;
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if (list_empty(&hcrx->ccid3hcrx_li_hist)) { /* no loss so far: p = 0 */
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const u32 sample = tfrc_rx_hist_sample_rtt(&hcrx->ccid3hcrx_hist, skb);
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/*
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* Empty loss history: no loss so far, hence p stays 0.
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* Sample RTT values, since an RTT estimate is required for the
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* computation of p when the first loss occurs; RFC 3448, 6.3.1.
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*/
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if (sample != 0)
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hcrx->ccid3hcrx_rtt = tfrc_ewma(hcrx->ccid3hcrx_rtt, sample, 9);
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}
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/*
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* Check if the periodic once-per-RTT feedback is due; RFC 4342, 10.3
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*/
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if (SUB16(dccp_hdr(skb)->dccph_ccval, hcrx->ccid3hcrx_last_counter) > 3)
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do_feedback = CCID3_FBACK_PERIODIC;
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update_records:
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tfrc_rx_hist_add_packet(&hcrx->ccid3hcrx_hist, skb, ndp);
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if (do_feedback)
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ccid3_hc_rx_send_feedback(sk, skb, do_feedback);
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}
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static int ccid3_hc_rx_init(struct ccid *ccid, struct sock *sk)
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@ -918,11 +837,8 @@ static int ccid3_hc_rx_init(struct ccid *ccid, struct sock *sk)
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ccid3_pr_debug("entry\n");
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hcrx->ccid3hcrx_state = TFRC_RSTATE_NO_DATA;
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INIT_LIST_HEAD(&hcrx->ccid3hcrx_hist);
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INIT_LIST_HEAD(&hcrx->ccid3hcrx_li_hist);
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hcrx->ccid3hcrx_tstamp_last_feedback =
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hcrx->ccid3hcrx_tstamp_last_ack = ktime_get_real();
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return 0;
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return tfrc_rx_hist_alloc(&hcrx->ccid3hcrx_hist);
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}
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static void ccid3_hc_rx_exit(struct sock *sk)
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@ -1,7 +1,8 @@
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/*
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* net/dccp/ccids/ccid3.h
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*
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* Copyright (c) 2005-6 The University of Waikato, Hamilton, New Zealand.
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* Copyright (c) 2005-7 The University of Waikato, Hamilton, New Zealand.
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* Copyright (c) 2007 The University of Aberdeen, Scotland, UK
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*
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* An implementation of the DCCP protocol
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*
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@ -135,9 +136,7 @@ enum ccid3_hc_rx_states {
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* @ccid3hcrx_x_recv - Receiver estimate of send rate (RFC 3448 4.3)
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* @ccid3hcrx_rtt - Receiver estimate of rtt (non-standard)
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* @ccid3hcrx_p - current loss event rate (RFC 3448 5.4)
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* @ccid3hcrx_seqno_nonloss - Last received non-loss sequence number
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* @ccid3hcrx_ccval_nonloss - Last received non-loss Window CCVal
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* @ccid3hcrx_ccval_last_counter - Tracks window counter (RFC 4342, 8.1)
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* @ccid3hcrx_last_counter - Tracks window counter (RFC 4342, 8.1)
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* @ccid3hcrx_state - receiver state, one of %ccid3_hc_rx_states
|
||||
* @ccid3hcrx_bytes_recv - Total sum of DCCP payload bytes
|
||||
* @ccid3hcrx_tstamp_last_feedback - Time at which last feedback was sent
|
||||
|
@ -152,14 +151,11 @@ struct ccid3_hc_rx_sock {
|
|||
#define ccid3hcrx_x_recv ccid3hcrx_tfrc.tfrcrx_x_recv
|
||||
#define ccid3hcrx_rtt ccid3hcrx_tfrc.tfrcrx_rtt
|
||||
#define ccid3hcrx_p ccid3hcrx_tfrc.tfrcrx_p
|
||||
u64 ccid3hcrx_seqno_nonloss:48,
|
||||
ccid3hcrx_ccval_nonloss:4,
|
||||
ccid3hcrx_ccval_last_counter:4;
|
||||
u8 ccid3hcrx_last_counter:4;
|
||||
enum ccid3_hc_rx_states ccid3hcrx_state:8;
|
||||
u32 ccid3hcrx_bytes_recv;
|
||||
ktime_t ccid3hcrx_tstamp_last_feedback;
|
||||
ktime_t ccid3hcrx_tstamp_last_ack;
|
||||
struct list_head ccid3hcrx_hist;
|
||||
struct tfrc_rx_hist ccid3hcrx_hist;
|
||||
struct list_head ccid3hcrx_li_hist;
|
||||
u16 ccid3hcrx_s;
|
||||
u32 ccid3hcrx_pinv;
|
||||
|
|
|
@ -129,6 +129,13 @@ static u32 dccp_li_calc_first_li(struct sock *sk,
|
|||
u16 s, u32 bytes_recv,
|
||||
u32 previous_x_recv)
|
||||
{
|
||||
/*
|
||||
* FIXME:
|
||||
* Will be rewritten in the upcoming new loss intervals code.
|
||||
* Has to be commented ou because it relies on the old rx history
|
||||
* data structures
|
||||
*/
|
||||
#if 0
|
||||
struct tfrc_rx_hist_entry *entry, *next, *tail = NULL;
|
||||
u32 x_recv, p;
|
||||
suseconds_t rtt, delta;
|
||||
|
@ -216,10 +223,10 @@ found:
|
|||
dccp_pr_debug("%s(%p), receive rate=%u bytes/s, implied "
|
||||
"loss rate=%u\n", dccp_role(sk), sk, x_recv, p);
|
||||
|
||||
if (p == 0)
|
||||
return ~0;
|
||||
else
|
||||
if (p != 0)
|
||||
return 1000000 / p;
|
||||
#endif
|
||||
return ~0;
|
||||
}
|
||||
|
||||
void dccp_li_update_li(struct sock *sk,
|
||||
|
|
|
@ -36,7 +36,9 @@
|
|||
*/
|
||||
|
||||
#include <linux/string.h>
|
||||
#include <linux/slab.h>
|
||||
#include "packet_history.h"
|
||||
#include "../../dccp.h"
|
||||
|
||||
/**
|
||||
* tfrc_tx_hist_entry - Simple singly-linked TX history list
|
||||
|
@ -111,19 +113,34 @@ u32 tfrc_tx_hist_rtt(struct tfrc_tx_hist_entry *head, const u64 seqno,
|
|||
}
|
||||
EXPORT_SYMBOL_GPL(tfrc_tx_hist_rtt);
|
||||
|
||||
|
||||
/**
|
||||
* tfrc_rx_hist_index - index to reach n-th entry after loss_start
|
||||
*/
|
||||
static inline u8 tfrc_rx_hist_index(const struct tfrc_rx_hist *h, const u8 n)
|
||||
{
|
||||
return (h->loss_start + n) & TFRC_NDUPACK;
|
||||
}
|
||||
|
||||
/**
|
||||
* tfrc_rx_hist_last_rcv - entry with highest-received-seqno so far
|
||||
*/
|
||||
static inline struct tfrc_rx_hist_entry *
|
||||
tfrc_rx_hist_last_rcv(const struct tfrc_rx_hist *h)
|
||||
{
|
||||
return h->ring[tfrc_rx_hist_index(h, h->loss_count)];
|
||||
}
|
||||
|
||||
/*
|
||||
* Receiver History Routines
|
||||
*/
|
||||
static struct kmem_cache *tfrc_rx_hist_slab;
|
||||
|
||||
struct tfrc_rx_hist_entry *tfrc_rx_hist_entry_new(const u32 ndp,
|
||||
void tfrc_rx_hist_add_packet(struct tfrc_rx_hist *h,
|
||||
const struct sk_buff *skb,
|
||||
const gfp_t prio)
|
||||
const u32 ndp)
|
||||
{
|
||||
struct tfrc_rx_hist_entry *entry = kmem_cache_alloc(tfrc_rx_hist_slab,
|
||||
prio);
|
||||
|
||||
if (entry != NULL) {
|
||||
struct tfrc_rx_hist_entry *entry = tfrc_rx_hist_last_rcv(h);
|
||||
const struct dccp_hdr *dh = dccp_hdr(skb);
|
||||
|
||||
entry->tfrchrx_seqno = DCCP_SKB_CB(skb)->dccpd_seq;
|
||||
|
@ -131,135 +148,180 @@ struct tfrc_rx_hist_entry *tfrc_rx_hist_entry_new(const u32 ndp,
|
|||
entry->tfrchrx_type = dh->dccph_type;
|
||||
entry->tfrchrx_ndp = ndp;
|
||||
entry->tfrchrx_tstamp = ktime_get_real();
|
||||
}
|
||||
|
||||
return entry;
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(tfrc_rx_hist_entry_new);
|
||||
EXPORT_SYMBOL_GPL(tfrc_rx_hist_add_packet);
|
||||
|
||||
static inline void tfrc_rx_hist_entry_delete(struct tfrc_rx_hist_entry *entry)
|
||||
{
|
||||
kmem_cache_free(tfrc_rx_hist_slab, entry);
|
||||
}
|
||||
|
||||
int tfrc_rx_hist_find_entry(const struct list_head *list, const u64 seq,
|
||||
u8 *ccval)
|
||||
{
|
||||
struct tfrc_rx_hist_entry *packet = NULL, *entry;
|
||||
|
||||
list_for_each_entry(entry, list, tfrchrx_node)
|
||||
if (entry->tfrchrx_seqno == seq) {
|
||||
packet = entry;
|
||||
break;
|
||||
}
|
||||
|
||||
if (packet)
|
||||
*ccval = packet->tfrchrx_ccval;
|
||||
|
||||
return packet != NULL;
|
||||
}
|
||||
|
||||
EXPORT_SYMBOL_GPL(tfrc_rx_hist_find_entry);
|
||||
struct tfrc_rx_hist_entry *
|
||||
tfrc_rx_hist_find_data_packet(const struct list_head *list)
|
||||
{
|
||||
struct tfrc_rx_hist_entry *entry, *packet = NULL;
|
||||
|
||||
list_for_each_entry(entry, list, tfrchrx_node)
|
||||
if (entry->tfrchrx_type == DCCP_PKT_DATA ||
|
||||
entry->tfrchrx_type == DCCP_PKT_DATAACK) {
|
||||
packet = entry;
|
||||
break;
|
||||
}
|
||||
|
||||
return packet;
|
||||
}
|
||||
|
||||
EXPORT_SYMBOL_GPL(tfrc_rx_hist_find_data_packet);
|
||||
|
||||
void tfrc_rx_hist_add_packet(struct list_head *rx_list,
|
||||
struct list_head *li_list,
|
||||
struct tfrc_rx_hist_entry *packet,
|
||||
u64 nonloss_seqno)
|
||||
{
|
||||
struct tfrc_rx_hist_entry *entry, *next;
|
||||
u8 num_later = 0;
|
||||
|
||||
list_add(&packet->tfrchrx_node, rx_list);
|
||||
|
||||
num_later = TFRC_RECV_NUM_LATE_LOSS + 1;
|
||||
|
||||
if (!list_empty(li_list)) {
|
||||
list_for_each_entry_safe(entry, next, rx_list, tfrchrx_node) {
|
||||
if (num_later == 0) {
|
||||
if (after48(nonloss_seqno,
|
||||
entry->tfrchrx_seqno)) {
|
||||
list_del_init(&entry->tfrchrx_node);
|
||||
tfrc_rx_hist_entry_delete(entry);
|
||||
}
|
||||
} else if (tfrc_rx_hist_entry_data_packet(entry))
|
||||
--num_later;
|
||||
}
|
||||
} else {
|
||||
int step = 0;
|
||||
u8 win_count = 0; /* Not needed, but lets shut up gcc */
|
||||
int tmp;
|
||||
/*
|
||||
* We have no loss interval history so we need at least one
|
||||
* rtt:s of data packets to approximate rtt.
|
||||
/**
|
||||
* tfrc_rx_hist_entry - return the n-th history entry after loss_start
|
||||
*/
|
||||
list_for_each_entry_safe(entry, next, rx_list, tfrchrx_node) {
|
||||
if (num_later == 0) {
|
||||
switch (step) {
|
||||
case 0:
|
||||
step = 1;
|
||||
/* OK, find next data packet */
|
||||
num_later = 1;
|
||||
break;
|
||||
case 1:
|
||||
step = 2;
|
||||
/* OK, find next data packet */
|
||||
num_later = 1;
|
||||
win_count = entry->tfrchrx_ccval;
|
||||
break;
|
||||
case 2:
|
||||
tmp = win_count - entry->tfrchrx_ccval;
|
||||
if (tmp < 0)
|
||||
tmp += TFRC_WIN_COUNT_LIMIT;
|
||||
if (tmp > TFRC_WIN_COUNT_PER_RTT + 1) {
|
||||
/*
|
||||
* We have found a packet older
|
||||
* than one rtt remove the rest
|
||||
*/
|
||||
step = 3;
|
||||
} else /* OK, find next data packet */
|
||||
num_later = 1;
|
||||
break;
|
||||
case 3:
|
||||
list_del_init(&entry->tfrchrx_node);
|
||||
tfrc_rx_hist_entry_delete(entry);
|
||||
break;
|
||||
}
|
||||
} else if (tfrc_rx_hist_entry_data_packet(entry))
|
||||
--num_later;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
EXPORT_SYMBOL_GPL(tfrc_rx_hist_add_packet);
|
||||
|
||||
void tfrc_rx_hist_purge(struct list_head *list)
|
||||
static inline struct tfrc_rx_hist_entry *
|
||||
tfrc_rx_hist_entry(const struct tfrc_rx_hist *h, const u8 n)
|
||||
{
|
||||
struct tfrc_rx_hist_entry *entry, *next;
|
||||
|
||||
list_for_each_entry_safe(entry, next, list, tfrchrx_node) {
|
||||
list_del_init(&entry->tfrchrx_node);
|
||||
tfrc_rx_hist_entry_delete(entry);
|
||||
}
|
||||
return h->ring[tfrc_rx_hist_index(h, n)];
|
||||
}
|
||||
|
||||
/**
|
||||
* tfrc_rx_hist_loss_prev - entry with highest-received-seqno before loss was detected
|
||||
*/
|
||||
static inline struct tfrc_rx_hist_entry *
|
||||
tfrc_rx_hist_loss_prev(const struct tfrc_rx_hist *h)
|
||||
{
|
||||
return h->ring[h->loss_start];
|
||||
}
|
||||
|
||||
/* has the packet contained in skb been seen before? */
|
||||
int tfrc_rx_hist_duplicate(struct tfrc_rx_hist *h, struct sk_buff *skb)
|
||||
{
|
||||
const u64 seq = DCCP_SKB_CB(skb)->dccpd_seq;
|
||||
int i;
|
||||
|
||||
if (dccp_delta_seqno(tfrc_rx_hist_loss_prev(h)->tfrchrx_seqno, seq) <= 0)
|
||||
return 1;
|
||||
|
||||
for (i = 1; i <= h->loss_count; i++)
|
||||
if (tfrc_rx_hist_entry(h, i)->tfrchrx_seqno == seq)
|
||||
return 1;
|
||||
|
||||
return 0;
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(tfrc_rx_hist_duplicate);
|
||||
|
||||
/* initialise loss detection and disable RTT sampling */
|
||||
static inline void tfrc_rx_hist_loss_indicated(struct tfrc_rx_hist *h)
|
||||
{
|
||||
h->loss_count = 1;
|
||||
}
|
||||
|
||||
/* indicate whether previously a packet was detected missing */
|
||||
static inline int tfrc_rx_hist_loss_pending(const struct tfrc_rx_hist *h)
|
||||
{
|
||||
return h->loss_count;
|
||||
}
|
||||
|
||||
/* any data packets missing between last reception and skb ? */
|
||||
int tfrc_rx_hist_new_loss_indicated(struct tfrc_rx_hist *h,
|
||||
const struct sk_buff *skb, u32 ndp)
|
||||
{
|
||||
int delta = dccp_delta_seqno(tfrc_rx_hist_last_rcv(h)->tfrchrx_seqno,
|
||||
DCCP_SKB_CB(skb)->dccpd_seq);
|
||||
|
||||
if (delta > 1 && ndp < delta)
|
||||
tfrc_rx_hist_loss_indicated(h);
|
||||
|
||||
return tfrc_rx_hist_loss_pending(h);
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(tfrc_rx_hist_new_loss_indicated);
|
||||
|
||||
int tfrc_rx_hist_alloc(struct tfrc_rx_hist *h)
|
||||
{
|
||||
int i;
|
||||
|
||||
for (i = 0; i <= TFRC_NDUPACK; i++) {
|
||||
h->ring[i] = kmem_cache_alloc(tfrc_rx_hist_slab, GFP_ATOMIC);
|
||||
if (h->ring[i] == NULL)
|
||||
goto out_free;
|
||||
}
|
||||
|
||||
h->loss_count = h->loss_start = 0;
|
||||
return 0;
|
||||
|
||||
out_free:
|
||||
while (i-- != 0) {
|
||||
kmem_cache_free(tfrc_rx_hist_slab, h->ring[i]);
|
||||
h->ring[i] = NULL;
|
||||
}
|
||||
return -ENOBUFS;
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(tfrc_rx_hist_alloc);
|
||||
|
||||
void tfrc_rx_hist_purge(struct tfrc_rx_hist *h)
|
||||
{
|
||||
int i;
|
||||
|
||||
for (i = 0; i <= TFRC_NDUPACK; ++i)
|
||||
if (h->ring[i] != NULL) {
|
||||
kmem_cache_free(tfrc_rx_hist_slab, h->ring[i]);
|
||||
h->ring[i] = NULL;
|
||||
}
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(tfrc_rx_hist_purge);
|
||||
|
||||
/**
|
||||
* tfrc_rx_hist_rtt_last_s - reference entry to compute RTT samples against
|
||||
*/
|
||||
static inline struct tfrc_rx_hist_entry *
|
||||
tfrc_rx_hist_rtt_last_s(const struct tfrc_rx_hist *h)
|
||||
{
|
||||
return h->ring[0];
|
||||
}
|
||||
|
||||
/**
|
||||
* tfrc_rx_hist_rtt_prev_s: previously suitable (wrt rtt_last_s) RTT-sampling entry
|
||||
*/
|
||||
static inline struct tfrc_rx_hist_entry *
|
||||
tfrc_rx_hist_rtt_prev_s(const struct tfrc_rx_hist *h)
|
||||
{
|
||||
return h->ring[h->rtt_sample_prev];
|
||||
}
|
||||
|
||||
/**
|
||||
* tfrc_rx_hist_sample_rtt - Sample RTT from timestamp / CCVal
|
||||
* Based on ideas presented in RFC 4342, 8.1. Returns 0 if it was not able
|
||||
* to compute a sample with given data - calling function should check this.
|
||||
*/
|
||||
u32 tfrc_rx_hist_sample_rtt(struct tfrc_rx_hist *h, const struct sk_buff *skb)
|
||||
{
|
||||
u32 sample = 0,
|
||||
delta_v = SUB16(dccp_hdr(skb)->dccph_ccval,
|
||||
tfrc_rx_hist_rtt_last_s(h)->tfrchrx_ccval);
|
||||
|
||||
if (delta_v < 1 || delta_v > 4) { /* unsuitable CCVal delta */
|
||||
if (h->rtt_sample_prev == 2) { /* previous candidate stored */
|
||||
sample = SUB16(tfrc_rx_hist_rtt_prev_s(h)->tfrchrx_ccval,
|
||||
tfrc_rx_hist_rtt_last_s(h)->tfrchrx_ccval);
|
||||
if (sample)
|
||||
sample = 4 / sample *
|
||||
ktime_us_delta(tfrc_rx_hist_rtt_prev_s(h)->tfrchrx_tstamp,
|
||||
tfrc_rx_hist_rtt_last_s(h)->tfrchrx_tstamp);
|
||||
else /*
|
||||
* FIXME: This condition is in principle not
|
||||
* possible but occurs when CCID is used for
|
||||
* two-way data traffic. I have tried to trace
|
||||
* it, but the cause does not seem to be here.
|
||||
*/
|
||||
DCCP_BUG("please report to dccp@vger.kernel.org"
|
||||
" => prev = %u, last = %u",
|
||||
tfrc_rx_hist_rtt_prev_s(h)->tfrchrx_ccval,
|
||||
tfrc_rx_hist_rtt_last_s(h)->tfrchrx_ccval);
|
||||
} else if (delta_v < 1) {
|
||||
h->rtt_sample_prev = 1;
|
||||
goto keep_ref_for_next_time;
|
||||
}
|
||||
|
||||
} else if (delta_v == 4) /* optimal match */
|
||||
sample = ktime_to_us(net_timedelta(tfrc_rx_hist_rtt_last_s(h)->tfrchrx_tstamp));
|
||||
else { /* suboptimal match */
|
||||
h->rtt_sample_prev = 2;
|
||||
goto keep_ref_for_next_time;
|
||||
}
|
||||
|
||||
if (unlikely(sample > DCCP_SANE_RTT_MAX)) {
|
||||
DCCP_WARN("RTT sample %u too large, using max\n", sample);
|
||||
sample = DCCP_SANE_RTT_MAX;
|
||||
}
|
||||
|
||||
h->rtt_sample_prev = 0; /* use current entry as next reference */
|
||||
keep_ref_for_next_time:
|
||||
|
||||
return sample;
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(tfrc_rx_hist_sample_rtt);
|
||||
|
||||
__init int packet_history_init(void)
|
||||
{
|
||||
tfrc_tx_hist_slab = kmem_cache_create("tfrc_tx_hist",
|
||||
|
|
|
@ -37,15 +37,9 @@
|
|||
#define _DCCP_PKT_HIST_
|
||||
|
||||
#include <linux/ktime.h>
|
||||
#include <linux/list.h>
|
||||
#include <linux/slab.h>
|
||||
#include "tfrc.h"
|
||||
#include <linux/types.h>
|
||||
|
||||
/* Number of later packets received before one is considered lost */
|
||||
#define TFRC_RECV_NUM_LATE_LOSS 3
|
||||
|
||||
#define TFRC_WIN_COUNT_PER_RTT 4
|
||||
#define TFRC_WIN_COUNT_LIMIT 16
|
||||
struct sk_buff;
|
||||
|
||||
struct tfrc_tx_hist_entry;
|
||||
|
||||
|
@ -54,11 +48,20 @@ extern void tfrc_tx_hist_purge(struct tfrc_tx_hist_entry **headp);
|
|||
extern u32 tfrc_tx_hist_rtt(struct tfrc_tx_hist_entry *head,
|
||||
const u64 seqno, const ktime_t now);
|
||||
|
||||
/*
|
||||
* Receiver History data structures and declarations
|
||||
/* Subtraction a-b modulo-16, respects circular wrap-around */
|
||||
#define SUB16(a, b) (((a) + 16 - (b)) & 0xF)
|
||||
|
||||
/* Number of packets to wait after a missing packet (RFC 4342, 6.1) */
|
||||
#define TFRC_NDUPACK 3
|
||||
|
||||
/**
|
||||
* tfrc_rx_hist_entry - Store information about a single received packet
|
||||
* @tfrchrx_seqno: DCCP packet sequence number
|
||||
* @tfrchrx_ccval: window counter value of packet (RFC 4342, 8.1)
|
||||
* @tfrchrx_ndp: the NDP count (if any) of the packet
|
||||
* @tfrchrx_tstamp: actual receive time of packet
|
||||
*/
|
||||
struct tfrc_rx_hist_entry {
|
||||
struct list_head tfrchrx_node;
|
||||
u64 tfrchrx_seqno:48,
|
||||
tfrchrx_ccval:4,
|
||||
tfrchrx_type:4;
|
||||
|
@ -66,42 +69,30 @@ struct tfrc_rx_hist_entry {
|
|||
ktime_t tfrchrx_tstamp;
|
||||
};
|
||||
|
||||
extern struct tfrc_rx_hist_entry *
|
||||
tfrc_rx_hist_entry_new(const u32 ndp,
|
||||
const struct sk_buff *skb,
|
||||
const gfp_t prio);
|
||||
/**
|
||||
* tfrc_rx_hist - RX history structure for TFRC-based protocols
|
||||
*
|
||||
* @ring: Packet history for RTT sampling and loss detection
|
||||
* @loss_count: Number of entries in circular history
|
||||
* @loss_start: Movable index (for loss detection)
|
||||
* @rtt_sample_prev: Used during RTT sampling, points to candidate entry
|
||||
*/
|
||||
struct tfrc_rx_hist {
|
||||
struct tfrc_rx_hist_entry *ring[TFRC_NDUPACK + 1];
|
||||
u8 loss_count:2,
|
||||
loss_start:2;
|
||||
#define rtt_sample_prev loss_start
|
||||
};
|
||||
|
||||
static inline struct tfrc_rx_hist_entry *
|
||||
tfrc_rx_hist_head(struct list_head *list)
|
||||
{
|
||||
struct tfrc_rx_hist_entry *head = NULL;
|
||||
extern void tfrc_rx_hist_add_packet(struct tfrc_rx_hist *h,
|
||||
const struct sk_buff *skb, const u32 ndp);
|
||||
|
||||
if (!list_empty(list))
|
||||
head = list_entry(list->next, struct tfrc_rx_hist_entry,
|
||||
tfrchrx_node);
|
||||
return head;
|
||||
}
|
||||
|
||||
extern int tfrc_rx_hist_find_entry(const struct list_head *list, const u64 seq,
|
||||
u8 *ccval);
|
||||
extern struct tfrc_rx_hist_entry *
|
||||
tfrc_rx_hist_find_data_packet(const struct list_head *list);
|
||||
|
||||
extern void tfrc_rx_hist_add_packet(struct list_head *rx_list,
|
||||
struct list_head *li_list,
|
||||
struct tfrc_rx_hist_entry *packet,
|
||||
u64 nonloss_seqno);
|
||||
|
||||
extern void tfrc_rx_hist_purge(struct list_head *list);
|
||||
|
||||
static inline int
|
||||
tfrc_rx_hist_entry_data_packet(const struct tfrc_rx_hist_entry *entry)
|
||||
{
|
||||
return entry->tfrchrx_type == DCCP_PKT_DATA ||
|
||||
entry->tfrchrx_type == DCCP_PKT_DATAACK;
|
||||
}
|
||||
|
||||
extern u64 tfrc_rx_hist_detect_loss(struct list_head *rx_list,
|
||||
struct list_head *li_list, u8 *win_loss);
|
||||
extern int tfrc_rx_hist_duplicate(struct tfrc_rx_hist *h, struct sk_buff *skb);
|
||||
extern int tfrc_rx_hist_new_loss_indicated(struct tfrc_rx_hist *h,
|
||||
const struct sk_buff *skb, u32 ndp);
|
||||
extern u32 tfrc_rx_hist_sample_rtt(struct tfrc_rx_hist *h,
|
||||
const struct sk_buff *skb);
|
||||
extern int tfrc_rx_hist_alloc(struct tfrc_rx_hist *h);
|
||||
extern void tfrc_rx_hist_purge(struct tfrc_rx_hist *h);
|
||||
|
||||
#endif /* _DCCP_PKT_HIST_ */
|
||||
|
|
Loading…
Reference in a new issue