From 1f152cd6faf96b524b6b7071b5cffe1916f9c5cc Mon Sep 17 00:00:00 2001 From: Florin Coras Date: Fri, 18 Aug 2017 19:28:03 -0700 Subject: tcp: retransmit and multi-buffer segment fixes and improvements - set session state as closed on session manager delete - enable retransmit as opposed to persist timer after persist timer completes - properly discard buffer chain bytes when new data overlaps ooo segments - don't use rxt bytes in snd space estimate used on tx path Change-Id: Id9cab686e532e5fe70c775d5440260e8eb890a9f Signed-off-by: Florin Coras --- src/vnet/tcp/tcp_output.c | 264 ++++++++++++++++++++++++++-------------------- 1 file changed, 152 insertions(+), 112 deletions(-) (limited to 'src/vnet/tcp/tcp_output.c') diff --git a/src/vnet/tcp/tcp_output.c b/src/vnet/tcp/tcp_output.c index 7da0c07349d..c56eadf8fdd 100644 --- a/src/vnet/tcp/tcp_output.c +++ b/src/vnet/tcp/tcp_output.c @@ -440,7 +440,8 @@ tcp_init_mss (tcp_connection_t * tc) always_inline int tcp_alloc_tx_buffers (tcp_main_t * tm, u8 thread_index, u32 n_free_buffers) { - vec_validate (tm->tx_buffers[thread_index], n_free_buffers - 1); + vec_validate (tm->tx_buffers[thread_index], + vec_len (tm->tx_buffers[thread_index]) + n_free_buffers - 1); _vec_len (tm->tx_buffers[thread_index]) = vlib_buffer_alloc_from_free_list (vlib_get_main (), tm->tx_buffers[thread_index], @@ -480,27 +481,31 @@ tcp_return_buffer (tcp_main_t * tm) _vec_len (my_tx_buffers) += 1; } -always_inline void +always_inline void * tcp_reuse_buffer (vlib_main_t * vm, vlib_buffer_t * b) { - vlib_buffer_t *it = b; - u32 save_free_list = b->flags & VLIB_BUFFER_FREE_LIST_INDEX_MASK; - do - { - it->current_data = 0; - it->current_length = 0; - it->total_length_not_including_first_buffer = 0; - } - while ((it->flags & VLIB_BUFFER_NEXT_PRESENT) - && (it = vlib_get_buffer (vm, it->next_buffer))); - if (b->flags & VLIB_BUFFER_NEXT_PRESENT) vlib_buffer_free_one (vm, b->next_buffer); - b->flags = save_free_list; + b->flags = 0; + b->current_data = 0; + b->current_length = 0; + b->total_length_not_including_first_buffer = 0; + vnet_buffer (b)->tcp.flags = 0; /* Leave enough space for headers */ - vlib_buffer_make_headroom (b, MAX_HDRS_LEN); + return vlib_buffer_make_headroom (b, MAX_HDRS_LEN); +} + +always_inline void * +tcp_init_buffer (vlib_main_t * vm, vlib_buffer_t * b) +{ + ASSERT ((b->flags & VLIB_BUFFER_NEXT_PRESENT) == 0); + b->flags = VNET_BUFFER_F_LOCALLY_ORIGINATED; + b->total_length_not_including_first_buffer = 0; vnet_buffer (b)->tcp.flags = 0; + + /* Leave enough space for headers */ + return vlib_buffer_make_headroom (b, MAX_HDRS_LEN); } /** @@ -632,6 +637,59 @@ tcp_enqueue_to_ip_lookup (vlib_main_t * vm, vlib_buffer_t * b, u32 bi, vlib_put_frame_to_node (vm, next_index, f); } +always_inline void +tcp_enqueue_to_output_i (vlib_main_t * vm, vlib_buffer_t * b, u32 bi, + u8 is_ip4, u8 flush) +{ + tcp_main_t *tm = vnet_get_tcp_main (); + u32 thread_index = vlib_get_thread_index (); + u32 *to_next, next_index; + vlib_frame_t *f; + + b->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED; + b->error = 0; + + /* Decide where to send the packet */ + next_index = is_ip4 ? tcp4_output_node.index : tcp6_output_node.index; + + /* Initialize the trajectory trace, if configured */ + if (VLIB_BUFFER_TRACE_TRAJECTORY > 0) + { + b->pre_data[0] = 1; + b->pre_data[1] = next_index; + } + + /* Get frame to v4/6 output node */ + f = tm->tx_frames[!is_ip4][thread_index]; + if (!f) + { + f = vlib_get_frame_to_node (vm, next_index); + ASSERT (f); + tm->tx_frames[!is_ip4][thread_index] = f; + } + to_next = vlib_frame_vector_args (f); + to_next[f->n_vectors] = bi; + f->n_vectors += 1; + if (flush || f->n_vectors == VLIB_FRAME_SIZE) + { + vlib_put_frame_to_node (vm, next_index, f); + tm->tx_frames[!is_ip4][thread_index] = 0; + } +} + +always_inline void +tcp_enqueue_to_output (vlib_main_t * vm, vlib_buffer_t * b, u32 bi, u8 is_ip4) +{ + tcp_enqueue_to_output_i (vm, b, bi, is_ip4, 0); +} + +always_inline void +tcp_enqueue_to_output_now (vlib_main_t * vm, vlib_buffer_t * b, u32 bi, + u8 is_ip4) +{ + tcp_enqueue_to_output_i (vm, b, bi, is_ip4, 1); +} + int tcp_make_reset_in_place (vlib_main_t * vm, vlib_buffer_t * b0, tcp_state_t state, u8 thread_index, u8 is_ip4) @@ -712,9 +770,11 @@ tcp_make_reset_in_place (vlib_main_t * vm, vlib_buffer_t * b0, /** * Send reset without reusing existing buffer + * + * It extracts connection info out of original packet */ void -tcp_send_reset (tcp_connection_t * tc, vlib_buffer_t * pkt, u8 is_ip4) +tcp_send_reset_w_pkt (tcp_connection_t * tc, vlib_buffer_t * pkt, u8 is_ip4) { vlib_buffer_t *b; u32 bi; @@ -730,9 +790,7 @@ tcp_send_reset (tcp_connection_t * tc, vlib_buffer_t * pkt, u8 is_ip4) return; b = vlib_get_buffer (vm, bi); - - /* Leave enough space for headers */ - vlib_buffer_make_headroom (b, MAX_HDRS_LEN); + tcp_init_buffer (vm, b); /* Make and write options */ tcp_hdr_len = sizeof (tcp_header_t); @@ -787,6 +845,38 @@ tcp_send_reset (tcp_connection_t * tc, vlib_buffer_t * pkt, u8 is_ip4) TCP_EVT_DBG (TCP_EVT_RST_SENT, tc); } +/** + * Build and set reset packet for connection + */ +void +tcp_send_reset (tcp_connection_t * tc) +{ + vlib_main_t *vm = vlib_get_main (); + tcp_main_t *tm = vnet_get_tcp_main (); + vlib_buffer_t *b; + u32 bi; + tcp_header_t *th; + u16 tcp_hdr_opts_len, advertise_wnd, opts_write_len; + u8 flags; + + if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi))) + return; + b = vlib_get_buffer (vm, bi); + tcp_init_buffer (vm, b); + + tc->snd_opts_len = tcp_make_options (tc, &tc->snd_opts, tc->state); + tcp_hdr_opts_len = tc->snd_opts_len + sizeof (tcp_header_t); + advertise_wnd = tcp_window_to_advertise (tc, TCP_STATE_ESTABLISHED); + flags = TCP_FLAG_RST; + th = vlib_buffer_push_tcp (b, tc->c_lcl_port, tc->c_rmt_port, tc->snd_nxt, + tc->rcv_nxt, tcp_hdr_opts_len, flags, + advertise_wnd); + opts_write_len = tcp_options_write ((u8 *) (th + 1), &tc->snd_opts); + ASSERT (opts_write_len == tc->snd_opts_len); + vnet_buffer (b)->tcp.connection_index = tc->c_c_index; + tcp_enqueue_to_output_now (vm, b, bi, tc->c_is_ip4); +} + void tcp_push_ip_hdr (tcp_main_t * tm, tcp_connection_t * tc, vlib_buffer_t * b) { @@ -835,9 +925,7 @@ tcp_send_syn (tcp_connection_t * tc) return; b = vlib_get_buffer (vm, bi); - - /* Leave enough space for headers */ - vlib_buffer_make_headroom (b, MAX_HDRS_LEN); + tcp_init_buffer (vm, b); /* Set random initial sequence */ time_now = tcp_time_now (); @@ -875,59 +963,6 @@ tcp_send_syn (tcp_connection_t * tc) TCP_EVT_DBG (TCP_EVT_SYN_SENT, tc); } -always_inline void -tcp_enqueue_to_output_i (vlib_main_t * vm, vlib_buffer_t * b, u32 bi, - u8 is_ip4, u8 flush) -{ - tcp_main_t *tm = vnet_get_tcp_main (); - u32 thread_index = vlib_get_thread_index (); - u32 *to_next, next_index; - vlib_frame_t *f; - - b->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED; - b->error = 0; - - /* Decide where to send the packet */ - next_index = is_ip4 ? tcp4_output_node.index : tcp6_output_node.index; - - /* Initialize the trajectory trace, if configured */ - if (VLIB_BUFFER_TRACE_TRAJECTORY > 0) - { - b->pre_data[0] = 1; - b->pre_data[1] = next_index; - } - - /* Get frame to v4/6 output node */ - f = tm->tx_frames[!is_ip4][thread_index]; - if (!f) - { - f = vlib_get_frame_to_node (vm, next_index); - ASSERT (f); - tm->tx_frames[!is_ip4][thread_index] = f; - } - to_next = vlib_frame_vector_args (f); - to_next[f->n_vectors] = bi; - f->n_vectors += 1; - if (flush || f->n_vectors == VLIB_FRAME_SIZE) - { - vlib_put_frame_to_node (vm, next_index, f); - tm->tx_frames[!is_ip4][thread_index] = 0; - } -} - -always_inline void -tcp_enqueue_to_output (vlib_main_t * vm, vlib_buffer_t * b, u32 bi, u8 is_ip4) -{ - tcp_enqueue_to_output_i (vm, b, bi, is_ip4, 0); -} - -always_inline void -tcp_enqueue_to_output_now (vlib_main_t * vm, vlib_buffer_t * b, u32 bi, - u8 is_ip4) -{ - tcp_enqueue_to_output_i (vm, b, bi, is_ip4, 1); -} - /** * Flush tx frame populated by retransmits and timer pops */ @@ -969,7 +1004,7 @@ tcp_send_fin (tcp_connection_t * tc) if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi))) return; b = vlib_get_buffer (vm, bi); - + /* buffer will be initialized by in tcp_make_fin */ tcp_make_fin (tc, b); tcp_enqueue_to_output_now (vm, b, bi, tc->c_is_ip4); tc->flags |= TCP_CONN_FINSNT; @@ -1013,6 +1048,8 @@ tcp_push_hdr_i (tcp_connection_t * tc, vlib_buffer_t * b, tcp_header_t *th; data_len = b->current_length + b->total_length_not_including_first_buffer; + ASSERT (!b->total_length_not_including_first_buffer + || (b->flags & VLIB_BUFFER_NEXT_PRESENT)); vnet_buffer (b)->tcp.flags = 0; if (compute_opts) @@ -1106,29 +1143,27 @@ tcp_prepare_retransmit_segment (tcp_connection_t * tc, u32 offset, * Make sure we can retransmit something */ available_bytes = stream_session_tx_fifo_max_dequeue (&tc->connection); + available_bytes -= offset; if (!available_bytes) return 0; max_deq_bytes = clib_min (tc->snd_mss, max_deq_bytes); max_deq_bytes = clib_min (available_bytes, max_deq_bytes); - seg_size = max_deq_bytes + MAX_HDRS_LEN; /* Start is beyond snd_congestion */ start = tc->snd_una + offset; if (seq_geq (start, tc->snd_congestion)) - { - goto done; - } + goto done; /* Don't overshoot snd_congestion */ if (seq_gt (start + max_deq_bytes, tc->snd_congestion)) { max_deq_bytes = tc->snd_congestion - start; if (max_deq_bytes == 0) - { - goto done; - } + goto done; } + seg_size = max_deq_bytes + MAX_HDRS_LEN; + /* * Prepare options */ @@ -1141,7 +1176,7 @@ tcp_prepare_retransmit_segment (tcp_connection_t * tc, u32 offset, if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi))) return 0; *b = vlib_get_buffer (vm, bi); - data = vlib_buffer_make_headroom (*b, MAX_HDRS_LEN); + data = tcp_init_buffer (vm, *b); /* Easy case, buffer size greater than mss */ if (PREDICT_TRUE (seg_size <= tm->bytes_per_buffer)) @@ -1162,7 +1197,6 @@ tcp_prepare_retransmit_segment (tcp_connection_t * tc, u32 offset, int i; n_bufs_per_seg = ceil ((double) seg_size / tm->bytes_per_buffer); - ASSERT (available_bytes >= max_deq_bytes); /* Make sure we have enough buffers */ available_bufs = vec_len (tm->tx_buffers[thread_index]); @@ -1182,8 +1216,6 @@ tcp_prepare_retransmit_segment (tcp_connection_t * tc, u32 offset, b[0]->current_length = n_bytes; b[0]->flags |= VLIB_BUFFER_TOTAL_LENGTH_VALID; b[0]->total_length_not_including_first_buffer = 0; - - tcp_push_hdr_i (tc, *b, tc->state, 0); max_deq_bytes -= n_bytes; chain_b = *b; @@ -1197,22 +1229,22 @@ tcp_prepare_retransmit_segment (tcp_connection_t * tc, u32 offset, chain_b->current_data = 0; data = vlib_buffer_get_current (chain_b); n_peeked = stream_session_peek_bytes (&tc->connection, data, - n_bytes, len_to_deq); - n_bytes += n_peeked; + offset + n_bytes, len_to_deq); ASSERT (n_peeked == len_to_deq); + n_bytes += n_peeked; chain_b->current_length = n_peeked; - b[0]->total_length_not_including_first_buffer += - chain_b->current_length; + chain_b->flags = 0; + chain_b->next_buffer = 0; /* update previous buffer */ prev_b->next_buffer = chain_bi; prev_b->flags |= VLIB_BUFFER_NEXT_PRESENT; - /* update current buffer */ - chain_b->next_buffer = 0; - max_deq_bytes -= n_peeked; + b[0]->total_length_not_including_first_buffer += n_peeked; } + + tcp_push_hdr_i (tc, *b, tc->state, 0); } ASSERT (n_bytes > 0); @@ -1348,7 +1380,7 @@ tcp_timer_retransmit_handler_i (u32 index, u8 is_syn) if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi))) return; b = vlib_get_buffer (vm, bi); - vlib_buffer_make_headroom (b, MAX_HDRS_LEN); + tcp_init_buffer (vm, b); tcp_push_hdr_i (tc, b, tc->state, 1); /* Account for the SYN */ @@ -1409,8 +1441,9 @@ tcp_timer_persist_handler (u32 index) u32 thread_index = vlib_get_thread_index (); tcp_connection_t *tc; vlib_buffer_t *b; - u32 bi, old_snd_nxt, snd_bytes = 0, available_bytes = 0; + u32 bi, old_snd_nxt, max_snd_bytes, available_bytes, offset; int n_bytes = 0; + u8 *data; tc = tcp_connection_get_if_valid (index, thread_index); @@ -1419,12 +1452,13 @@ tcp_timer_persist_handler (u32 index) /* Make sure timer handle is set to invalid */ tc->timers[TCP_TIMER_PERSIST] = TCP_TIMER_HANDLE_INVALID; + offset = tc->snd_una_max - tc->snd_una; /* Problem already solved or worse */ available_bytes = stream_session_tx_fifo_max_dequeue (&tc->connection); if (tc->state == TCP_STATE_CLOSED || tc->state > TCP_STATE_ESTABLISHED || tc->snd_wnd > tc->snd_mss || tcp_in_recovery (tc) - || !available_bytes) + || !available_bytes || available_bytes <= offset) return; /* Increment RTO backoff */ @@ -1437,18 +1471,17 @@ tcp_timer_persist_handler (u32 index) if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi))) return; b = vlib_get_buffer (vm, bi); + data = tcp_init_buffer (vm, b); - tcp_validate_txf_size (tc, tc->snd_una_max - tc->snd_una); + tcp_validate_txf_size (tc, offset); tc->snd_opts_len = tcp_make_options (tc, &tc->snd_opts, tc->state); - snd_bytes = clib_min (tc->snd_mss, tm->bytes_per_buffer); - n_bytes = stream_session_peek_bytes (&tc->connection, - vlib_buffer_get_current (b), - tc->snd_una_max - tc->snd_una, - snd_bytes); - ASSERT (n_bytes != 0); + max_snd_bytes = clib_min (tc->snd_mss, tm->bytes_per_buffer - MAX_HDRS_LEN); + n_bytes = stream_session_peek_bytes (&tc->connection, data, offset, + max_snd_bytes); b->current_length = n_bytes; - ASSERT (tc->snd_nxt == tc->snd_una_max || tc->rto_boff > 1 - || tcp_timer_is_active (tc, TCP_TIMER_RETRANSMIT)); + ASSERT (n_bytes != 0 && (tc->snd_nxt == tc->snd_una_max || tc->rto_boff > 1 + || tcp_timer_is_active (tc, + TCP_TIMER_RETRANSMIT))); /* Allow updating of snd_una_max but don't update snd_nxt */ old_snd_nxt = tc->snd_nxt; @@ -1456,8 +1489,8 @@ tcp_timer_persist_handler (u32 index) tc->snd_nxt = old_snd_nxt; tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4); - /* Re-enable persist timer */ - tcp_persist_timer_set (tc); + /* Just sent new data, enable retransmit */ + tcp_retransmit_timer_update (tc); } /** @@ -1490,7 +1523,7 @@ void tcp_fast_retransmit_sack (tcp_connection_t * tc) { vlib_main_t *vm = vlib_get_main (); - u32 n_written = 0, offset = 0, max_bytes; + u32 n_written = 0, offset, max_bytes; vlib_buffer_t *b = 0; sack_scoreboard_hole_t *hole; sack_scoreboard_t *sb; @@ -1523,7 +1556,9 @@ tcp_fast_retransmit_sack (tcp_connection_t * tc) * unSACKed sequence number SHOULD be returned, and RescueRxt set to * RecoveryPoint. HighRxt MUST NOT be updated. */ - max_bytes = clib_min (tc->snd_mss, snd_space); + max_bytes = clib_min (tc->snd_mss, + tc->snd_congestion - tc->snd_una); + max_bytes = clib_min (max_bytes, snd_space); offset = tc->snd_congestion - tc->snd_una - max_bytes; sb->rescue_rxt = tc->snd_congestion; tc->snd_nxt = tc->snd_una + offset; @@ -1535,9 +1570,12 @@ tcp_fast_retransmit_sack (tcp_connection_t * tc) break; } - max_bytes = snd_limited ? tc->snd_mss : hole->end - sb->high_rxt; + max_bytes = clib_min (hole->end - sb->high_rxt, snd_space); + max_bytes = snd_limited ? clib_min (max_bytes, tc->snd_mss) : max_bytes; + if (max_bytes == 0) + break; offset = sb->high_rxt - tc->snd_una; - tc->snd_nxt = tc->snd_una + offset; + tc->snd_nxt = sb->high_rxt; n_written = tcp_prepare_retransmit_segment (tc, offset, max_bytes, &b); /* Nothing left to retransmit */ @@ -1547,6 +1585,7 @@ tcp_fast_retransmit_sack (tcp_connection_t * tc) bi = vlib_get_buffer_index (vm, b); sb->high_rxt += n_written; tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4); + ASSERT (n_written <= snd_space); snd_space -= n_written; } @@ -1835,6 +1874,7 @@ tcp_push_header (transport_connection_t * tconn, vlib_buffer_t * b) tc = (tcp_connection_t *) tconn; tcp_push_hdr_i (tc, b, TCP_STATE_ESTABLISHED, 0); + ASSERT (seq_leq (tc->snd_una_max, tc->snd_una + tc->snd_wnd)); if (tc->rtt_ts == 0 && !tcp_in_cong_recovery (tc)) { -- cgit 1.2.3-korg