diff options
Diffstat (limited to 'net/dccp/ccids/ccid3.c')
| -rw-r--r-- | net/dccp/ccids/ccid3.c | 72 |
1 files changed, 60 insertions, 12 deletions
diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c index 8266dfde89c..8f112d18d45 100644 --- a/net/dccp/ccids/ccid3.c +++ b/net/dccp/ccids/ccid3.c @@ -1,6 +1,7 @@ /* * net/dccp/ccids/ccid3.c * + * Copyright (c) 2007 The University of Aberdeen, Scotland, UK * Copyright (c) 2005-7 The University of Waikato, Hamilton, New Zealand. * Copyright (c) 2005-7 Ian McDonald <ian.mcdonald@jandi.co.nz> * @@ -33,11 +34,7 @@ * along with this program; if not, write to the Free Software * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ -#include "../ccid.h" #include "../dccp.h" -#include "lib/packet_history.h" -#include "lib/loss_interval.h" -#include "lib/tfrc.h" #include "ccid3.h" #include <asm/unaligned.h> @@ -757,6 +754,46 @@ static int ccid3_hc_rx_insert_options(struct sock *sk, struct sk_buff *skb) return 0; } +/** ccid3_first_li - Implements [RFC 3448, 6.3.1] + * + * Determine the length of the first loss interval via inverse lookup. + * Assume that X_recv can be computed by the throughput equation + * s + * X_recv = -------- + * R * fval + * Find some p such that f(p) = fval; return 1/p (scaled). + */ +static u32 ccid3_first_li(struct sock *sk) +{ + struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk); + u32 x_recv, p, delta; + u64 fval; + + if (hcrx->ccid3hcrx_rtt == 0) { + DCCP_WARN("No RTT estimate available, using fallback RTT\n"); + hcrx->ccid3hcrx_rtt = DCCP_FALLBACK_RTT; + } + + delta = ktime_to_us(net_timedelta(hcrx->ccid3hcrx_tstamp_last_feedback)); + x_recv = scaled_div32(hcrx->ccid3hcrx_bytes_recv, delta); + if (x_recv == 0) { /* would also trigger divide-by-zero */ + DCCP_WARN("X_recv==0\n"); + if ((x_recv = hcrx->ccid3hcrx_x_recv) == 0) { + DCCP_BUG("stored value of X_recv is zero"); + return ~0U; + } + } + + fval = scaled_div(hcrx->ccid3hcrx_s, hcrx->ccid3hcrx_rtt); + fval = scaled_div32(fval, x_recv); + p = tfrc_calc_x_reverse_lookup(fval); + + ccid3_pr_debug("%s(%p), receive rate=%u bytes/s, implied " + "loss rate=%u\n", dccp_role(sk), sk, x_recv, p); + + return p == 0 ? ~0U : scaled_div(1, p); +} + static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb) { struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk); @@ -794,6 +831,14 @@ static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb) /* * Handle pending losses and otherwise check for new loss */ + if (tfrc_rx_hist_loss_pending(&hcrx->ccid3hcrx_hist) && + tfrc_rx_handle_loss(&hcrx->ccid3hcrx_hist, + &hcrx->ccid3hcrx_li_hist, + skb, ndp, ccid3_first_li, sk) ) { + do_feedback = CCID3_FBACK_PARAM_CHANGE; + goto done_receiving; + } + if (tfrc_rx_hist_new_loss_indicated(&hcrx->ccid3hcrx_hist, skb, ndp)) goto update_records; @@ -803,7 +848,7 @@ static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb) if (unlikely(!is_data_packet)) goto update_records; - if (list_empty(&hcrx->ccid3hcrx_li_hist)) { /* no loss so far: p = 0 */ + if (!tfrc_lh_is_initialised(&hcrx->ccid3hcrx_li_hist)) { const u32 sample = tfrc_rx_hist_sample_rtt(&hcrx->ccid3hcrx_hist, skb); /* * Empty loss history: no loss so far, hence p stays 0. @@ -812,6 +857,13 @@ static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb) */ if (sample != 0) hcrx->ccid3hcrx_rtt = tfrc_ewma(hcrx->ccid3hcrx_rtt, sample, 9); + + } else if (tfrc_lh_update_i_mean(&hcrx->ccid3hcrx_li_hist, skb)) { + /* + * Step (3) of [RFC 3448, 6.1]: Recompute I_mean and, if I_mean + * has decreased (resp. p has increased), send feedback now. + */ + do_feedback = CCID3_FBACK_PARAM_CHANGE; } /* @@ -823,6 +875,7 @@ static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb) update_records: tfrc_rx_hist_add_packet(&hcrx->ccid3hcrx_hist, skb, ndp); +done_receiving: if (do_feedback) ccid3_hc_rx_send_feedback(sk, skb, do_feedback); } @@ -831,10 +884,8 @@ static int ccid3_hc_rx_init(struct ccid *ccid, struct sock *sk) { struct ccid3_hc_rx_sock *hcrx = ccid_priv(ccid); - ccid3_pr_debug("entry\n"); - hcrx->ccid3hcrx_state = TFRC_RSTATE_NO_DATA; - INIT_LIST_HEAD(&hcrx->ccid3hcrx_li_hist); + tfrc_lh_init(&hcrx->ccid3hcrx_li_hist); return tfrc_rx_hist_alloc(&hcrx->ccid3hcrx_hist); } @@ -844,11 +895,8 @@ static void ccid3_hc_rx_exit(struct sock *sk) ccid3_hc_rx_set_state(sk, TFRC_RSTATE_TERM); - /* Empty packet history */ tfrc_rx_hist_purge(&hcrx->ccid3hcrx_hist); - - /* Empty loss interval history */ - dccp_li_hist_purge(&hcrx->ccid3hcrx_li_hist); + tfrc_lh_cleanup(&hcrx->ccid3hcrx_li_hist); } static void ccid3_hc_rx_get_info(struct sock *sk, struct tcp_info *info) |