X-Git-Url: https://gerrit.fd.io/r/gitweb?a=blobdiff_plain;f=src%2Fvnet%2Ftcp%2Ftcp_output.c;h=7e431cd0454f5faca26149f9d4166f0b85b9d190;hb=e04c29942af6a130591059679531c9ffa3d7237a;hp=dbcf1f74975febd4d52962746e29ec72ed913955;hpb=fb38095d1c9d1b84850f345f0344f82b9ae2c375;p=vpp.git diff --git a/src/vnet/tcp/tcp_output.c b/src/vnet/tcp/tcp_output.c index dbcf1f74975..7e431cd0454 100644 --- a/src/vnet/tcp/tcp_output.c +++ b/src/vnet/tcp/tcp_output.c @@ -90,6 +90,15 @@ tcp_window_compute_scale (u32 available_space) return wnd_scale; } +/** + * TCP's IW as recommended by RFC6928 + */ +always_inline u32 +tcp_initial_wnd_unscaled (tcp_connection_t * tc) +{ + return TCP_IW_N_SEGMENTS * dummy_mtu; +} + /** * Compute initial window and scale factor. As per RFC1323, window field in * SYN and SYN-ACK segments is never scaled. @@ -97,18 +106,15 @@ tcp_window_compute_scale (u32 available_space) u32 tcp_initial_window_to_advertise (tcp_connection_t * tc) { - u32 available_space; + u32 max_fifo; /* Initial wnd for SYN. Fifos are not allocated yet. - * Use some predefined value */ - if (tc->state != TCP_STATE_SYN_RCVD) - { - return TCP_DEFAULT_RX_FIFO_SIZE; - } + * Use some predefined value. For SYN-ACK we still want the + * scale to be computed in the same way */ + max_fifo = TCP_MAX_RX_FIFO_SIZE; - available_space = stream_session_max_enqueue (&tc->connection); - tc->rcv_wscale = tcp_window_compute_scale (available_space); - tc->rcv_wnd = clib_min (available_space, TCP_WND_MAX << tc->rcv_wscale); + tc->rcv_wscale = tcp_window_compute_scale (max_fifo); + tc->rcv_wnd = tcp_initial_wnd_unscaled (tc); return clib_min (tc->rcv_wnd, TCP_WND_MAX); } @@ -119,23 +125,43 @@ tcp_initial_window_to_advertise (tcp_connection_t * tc) u32 tcp_window_to_advertise (tcp_connection_t * tc, tcp_state_t state) { - u32 available_space, wnd, scaled_space; + u32 available_space, max_fifo, observed_wnd; - if (state != TCP_STATE_ESTABLISHED) + if (state < TCP_STATE_ESTABLISHED) return tcp_initial_window_to_advertise (tc); + /* + * Figure out how much space we have available + */ available_space = stream_session_max_enqueue (&tc->connection); - scaled_space = available_space >> tc->rcv_wscale; + max_fifo = stream_session_fifo_size (&tc->connection); + + ASSERT (tc->opt.mss < max_fifo); + + if (available_space < tc->opt.mss && available_space < max_fifo / 8) + available_space = 0; - /* Need to update scale */ - if (PREDICT_FALSE ((scaled_space == 0 && available_space != 0)) - || (scaled_space >= TCP_WND_MAX)) - tc->rcv_wscale = tcp_window_compute_scale (available_space); + /* + * Use the above and what we know about what we've previously advertised + * to compute the new window + */ + observed_wnd = tc->rcv_wnd - (tc->rcv_nxt - tc->rcv_las); - wnd = clib_min (available_space, TCP_WND_MAX << tc->rcv_wscale); - tc->rcv_wnd = wnd; + /* Bad. Thou shalt not shrink */ + if (available_space < observed_wnd) + { + if (available_space == 0) + clib_warning ("Didn't shrink rcv window despite not having space"); + } + + tc->rcv_wnd = clib_min (available_space, TCP_WND_MAX << tc->rcv_wscale); + + if (tc->rcv_wnd == 0) + { + tc->flags |= TCP_CONN_SENT_RCV_WND0; + } - return wnd >> tc->rcv_wscale; + return tc->rcv_wnd >> tc->rcv_wscale; } /** @@ -225,7 +251,7 @@ tcp_options_write (u8 * data, tcp_options_t * opts) } always_inline int -tcp_make_syn_options (tcp_options_t * opts, u32 initial_wnd) +tcp_make_syn_options (tcp_options_t * opts, u8 wnd_scale) { u8 len = 0; @@ -234,7 +260,7 @@ tcp_make_syn_options (tcp_options_t * opts, u32 initial_wnd) len += TCP_OPTION_LEN_MSS; opts->flags |= TCP_OPTS_FLAG_WSCALE; - opts->wscale = tcp_window_compute_scale (initial_wnd); + opts->wscale = wnd_scale; len += TCP_OPTION_LEN_WINDOW_SCALE; opts->flags |= TCP_OPTS_FLAG_TSTAMP; @@ -327,8 +353,7 @@ tcp_make_options (tcp_connection_t * tc, tcp_options_t * opts, case TCP_STATE_SYN_RCVD: return tcp_make_synack_options (tc, opts); case TCP_STATE_SYN_SENT: - return tcp_make_syn_options (opts, - tcp_initial_window_to_advertise (tc)); + return tcp_make_syn_options (opts, tc->rcv_wscale); default: clib_warning ("Not handled!"); return 0; @@ -732,7 +757,7 @@ tcp_send_syn (tcp_connection_t * tc) /* Make and write options */ memset (&snd_opts, 0, sizeof (snd_opts)); - tcp_opts_len = tcp_make_syn_options (&snd_opts, initial_wnd); + tcp_opts_len = tcp_make_syn_options (&snd_opts, tc->rcv_wscale); tcp_hdr_opts_len = tcp_opts_len + sizeof (tcp_header_t); th = vlib_buffer_push_tcp (b, tc->c_lcl_port, tc->c_rmt_port, tc->iss, @@ -900,7 +925,7 @@ tcp_prepare_retransmit_segment (tcp_connection_t * tc, vlib_buffer_t * b, tcp_reuse_buffer (vm, b); - ASSERT (tc->state == TCP_STATE_ESTABLISHED); + ASSERT (tc->state >= TCP_STATE_ESTABLISHED); ASSERT (max_bytes != 0); if (tcp_opts_sack_permitted (&tc->opt)) @@ -929,7 +954,6 @@ tcp_prepare_retransmit_segment (tcp_connection_t * tc, vlib_buffer_t * b, max_bytes); ASSERT (n_bytes != 0); - tc->snd_nxt += n_bytes; tcp_push_hdr_i (tc, b, tc->state); return n_bytes; @@ -967,7 +991,7 @@ tcp_timer_retransmit_handler_i (u32 index, u8 is_syn) tcp_get_free_buffer_index (tm, &bi); b = vlib_get_buffer (vm, bi); - if (tc->state == TCP_STATE_ESTABLISHED) + if (tc->state >= TCP_STATE_ESTABLISHED) { tcp_fastrecovery_off (tc); @@ -977,6 +1001,12 @@ tcp_timer_retransmit_handler_i (u32 index, u8 is_syn) /* Figure out what and how many bytes we can send */ snd_space = tcp_available_snd_space (tc); max_bytes = clib_min (tc->snd_mss, snd_space); + + if (max_bytes == 0) + { + clib_warning ("no wnd to retransmit"); + return; + } tcp_prepare_retransmit_segment (tc, b, max_bytes); tc->rtx_bytes += max_bytes; @@ -996,7 +1026,11 @@ tcp_timer_retransmit_handler_i (u32 index, u8 is_syn) tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX); vlib_buffer_make_headroom (b, MAX_HDRS_LEN); + tcp_push_hdr_i (tc, b, tc->state); + + /* Account for the SYN */ + tc->snd_nxt += 1; } if (!is_syn) @@ -1163,8 +1197,8 @@ tcp46_output_inline (vlib_main_t * vm, if (PREDICT_FALSE (vnet_buffer (b0)->tcp.flags & TCP_BUF_FLAG_DUPACK)) { + ASSERT (tc0->snt_dupacks > 0); tc0->snt_dupacks--; - ASSERT (tc0->snt_dupacks >= 0); if (!tcp_session_has_ooo_data (tc0)) { error0 = TCP_ERROR_FILTERED_DUPACKS;