/* * Copyright (c) 2016 Cisco and/or its affiliates. * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at: * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #include <vnet/tcp/tcp.h> #include <vnet/lisp-cp/packets.h> #include <math.h> vlib_node_registration_t tcp4_output_node; vlib_node_registration_t tcp6_output_node; typedef enum _tcp_output_next { TCP_OUTPUT_NEXT_DROP, TCP_OUTPUT_NEXT_IP_LOOKUP, TCP_OUTPUT_N_NEXT } tcp_output_next_t; #define foreach_tcp4_output_next \ _ (DROP, "error-drop") \ _ (IP_LOOKUP, "ip4-lookup") #define foreach_tcp6_output_next \ _ (DROP, "error-drop") \ _ (IP_LOOKUP, "ip6-lookup") static char *tcp_error_strings[] = { #define tcp_error(n,s) s, #include <vnet/tcp/tcp_error.def> #undef tcp_error }; typedef struct { tcp_header_t tcp_header; tcp_connection_t tcp_connection; } tcp_tx_trace_t; u16 dummy_mtu = 1460; u8 * format_tcp_tx_trace (u8 * s, va_list * args) { CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *); CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *); tcp_tx_trace_t *t = va_arg (*args, tcp_tx_trace_t *); u32 indent = format_get_indent (s); s = format (s, "%U\n%U%U", format_tcp_header, &t->tcp_header, 128, format_white_space, indent, format_tcp_connection, &t->tcp_connection, 1); return s; } static u8 tcp_window_compute_scale (u32 window) { u8 wnd_scale = 0; while (wnd_scale < TCP_MAX_WND_SCALE && (window >> wnd_scale) > TCP_WND_MAX) wnd_scale++; return wnd_scale; } /** * Update max segment size we're able to process. * * The value is constrained by our interface's MTU and IP options. It is * also what we advertise to our peer. */ void tcp_update_rcv_mss (tcp_connection_t * tc) { /* TODO find our iface MTU */ tc->mss = dummy_mtu - sizeof (tcp_header_t); } /** * TCP's initial window */ always_inline u32 tcp_initial_wnd_unscaled (tcp_connection_t * tc) { /* RFC 6928 recommends the value lower. However at the time our connections * are initialized, fifos may not be allocated. Therefore, advertise the * smallest possible unscaled window size and update once fifos are * assigned to the session. */ /* tcp_update_rcv_mss (tc); TCP_IW_N_SEGMENTS * tc->mss; */ return TCP_MIN_RX_FIFO_SIZE; } /** * Compute initial window and scale factor. As per RFC1323, window field in * SYN and SYN-ACK segments is never scaled. */ u32 tcp_initial_window_to_advertise (tcp_connection_t * tc) { u32 max_fifo; /* Initial wnd for SYN. Fifos are not allocated yet. * 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; 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); } /** * Compute and return window to advertise, scaled as per RFC1323 */ u32 tcp_window_to_advertise (tcp_connection_t * tc, tcp_state_t state) { if (state < TCP_STATE_ESTABLISHED) return tcp_initial_window_to_advertise (tc); tcp_update_rcv_wnd (tc); if (tc->rcv_wnd == 0) { tc->flags |= TCP_CONN_SENT_RCV_WND0; } else { tc->flags &= ~TCP_CONN_SENT_RCV_WND0; } return tc->rcv_wnd >> tc->rcv_wscale; } void tcp_update_rcv_wnd (tcp_connection_t * tc) { i32 observed_wnd; u32 available_space, max_fifo, wnd; /* * Figure out how much space we have available */ available_space = stream_session_max_rx_enqueue (&tc->connection); max_fifo = stream_session_rx_fifo_size (&tc->connection); ASSERT (tc->rcv_opts.mss < max_fifo); if (available_space < tc->rcv_opts.mss && available_space < max_fifo >> 3) available_space = 0; /* * Use the above and what we know about what we've previously advertised * to compute the new window */ observed_wnd = (i32) tc->rcv_wnd - (tc->rcv_nxt - tc->rcv_las); if (observed_wnd < 0) observed_wnd = 0; /* Bad. Thou shalt not shrink */ if (available_space < observed_wnd) { wnd = observed_wnd; TCP_EVT_DBG (TCP_EVT_RCV_WND_SHRUNK, tc, observed_wnd, available_space); } else { wnd = available_space; } /* Make sure we have a multiple of rcv_wscale */ if (wnd && tc->rcv_wscale) { wnd &= ~(1 << tc->rcv_wscale); if (wnd == 0) wnd = 1 << tc->rcv_wscale; } tc->rcv_wnd = clib_min (wnd, TCP_WND_MAX << tc->rcv_wscale); } /** * Write TCP options to segment. */ u32 tcp_options_write (u8 * data, tcp_options_t * opts) { u32 opts_len = 0; u32 buf, seq_len = 4; if (tcp_opts_mss (opts)) { *data++ = TCP_OPTION_MSS; *data++ = TCP_OPTION_LEN_MSS; buf = clib_host_to_net_u16 (opts->mss); clib_memcpy (data, &buf, sizeof (opts->mss)); data += sizeof (opts->mss); opts_len += TCP_OPTION_LEN_MSS; } if (tcp_opts_wscale (opts)) { *data++ = TCP_OPTION_WINDOW_SCALE; *data++ = TCP_OPTION_LEN_WINDOW_SCALE; *data++ = opts->wscale; opts_len += TCP_OPTION_LEN_WINDOW_SCALE; } if (tcp_opts_sack_permitted (opts)) { *data++ = TCP_OPTION_SACK_PERMITTED; *data++ = TCP_OPTION_LEN_SACK_PERMITTED; opts_len += TCP_OPTION_LEN_SACK_PERMITTED; } if (tcp_opts_tstamp (opts)) { *data++ = TCP_OPTION_TIMESTAMP; *data++ = TCP_OPTION_LEN_TIMESTAMP; buf = clib_host_to_net_u32 (opts->tsval); clib_memcpy (data, &buf, sizeof (opts->tsval)); data += sizeof (opts->tsval); buf = clib_host_to_net_u32 (opts->tsecr); clib_memcpy (data, &buf, sizeof (opts->tsecr)); data += sizeof (opts->tsecr); opts_len += TCP_OPTION_LEN_TIMESTAMP; } if (tcp_opts_sack (opts)) { int i; u32 n_sack_blocks = clib_min (vec_len (opts->sacks), TCP_OPTS_MAX_SACK_BLOCKS); if (n_sack_blocks != 0) { *data++ = TCP_OPTION_SACK_BLOCK; *data++ = 2 + n_sack_blocks * TCP_OPTION_LEN_SACK_BLOCK; for (i = 0; i < n_sack_blocks; i++) { buf = clib_host_to_net_u32 (opts->sacks[i].start); clib_memcpy (data, &buf, seq_len); data += seq_len; buf = clib_host_to_net_u32 (opts->sacks[i].end); clib_memcpy (data, &buf, seq_len); data += seq_len; } opts_len += 2 + n_sack_blocks * TCP_OPTION_LEN_SACK_BLOCK; } } /* Terminate TCP options */ if (opts_len % 4) { *data++ = TCP_OPTION_EOL; opts_len += TCP_OPTION_LEN_EOL; } /* Pad with zeroes to a u32 boundary */ while (opts_len % 4) { *data++ = TCP_OPTION_NOOP; opts_len += TCP_OPTION_LEN_NOOP; } return opts_len; } always_inline int tcp_make_syn_options (tcp_options_t * opts, u8 wnd_scale) { u8 len = 0; opts->flags |= TCP_OPTS_FLAG_MSS; opts->mss = dummy_mtu; /*XXX discover that */ len += TCP_OPTION_LEN_MSS; opts->flags |= TCP_OPTS_FLAG_WSCALE; opts->wscale = wnd_scale; len += TCP_OPTION_LEN_WINDOW_SCALE; opts->flags |= TCP_OPTS_FLAG_TSTAMP; opts->tsval = tcp_time_now (); opts->tsecr = 0; len += TCP_OPTION_LEN_TIMESTAMP; if (TCP_USE_SACKS) { opts->flags |= TCP_OPTS_FLAG_SACK_PERMITTED; len += TCP_OPTION_LEN_SACK_PERMITTED; } /* Align to needed boundary */ len += (TCP_OPTS_ALIGN - len % TCP_OPTS_ALIGN) % TCP_OPTS_ALIGN; return len; } always_inline int tcp_make_synack_options (tcp_connection_t * tc, tcp_options_t * opts) { u8 len = 0; opts->flags |= TCP_OPTS_FLAG_MSS; opts->mss = tc->mss; len += TCP_OPTION_LEN_MSS; if (tcp_opts_wscale (&tc->rcv_opts)) { opts->flags |= TCP_OPTS_FLAG_WSCALE; opts->wscale = tc->rcv_wscale; len += TCP_OPTION_LEN_WINDOW_SCALE; } if (tcp_opts_tstamp (&tc->rcv_opts)) { opts->flags |= TCP_OPTS_FLAG_TSTAMP; opts->tsval = tcp_time_now (); opts->tsecr = tc->tsval_recent; len += TCP_OPTION_LEN_TIMESTAMP; } if (tcp_opts_sack_permitted (&tc->rcv_opts)) { opts->flags |= TCP_OPTS_FLAG_SACK_PERMITTED; len += TCP_OPTION_LEN_SACK_PERMITTED; } /* Align to needed boundary */ len += (TCP_OPTS_ALIGN - len % TCP_OPTS_ALIGN) % TCP_OPTS_ALIGN; return len; } always_inline int tcp_make_established_options (tcp_connection_t * tc, tcp_options_t * opts) { u8 len = 0; opts->flags = 0; if (tcp_opts_tstamp (&tc->rcv_opts)) { opts->flags |= TCP_OPTS_FLAG_TSTAMP; opts->tsval = tcp_time_now (); opts->tsecr = tc->tsval_recent; len += TCP_OPTION_LEN_TIMESTAMP; } if (tcp_opts_sack_permitted (&tc->rcv_opts)) { if (vec_len (tc->snd_sacks)) { opts->flags |= TCP_OPTS_FLAG_SACK; opts->sacks = tc->snd_sacks; opts->n_sack_blocks = clib_min (vec_len (tc->snd_sacks), TCP_OPTS_MAX_SACK_BLOCKS); len += 2 + TCP_OPTION_LEN_SACK_BLOCK * opts->n_sack_blocks; } } /* Align to needed boundary */ len += (TCP_OPTS_ALIGN - len % TCP_OPTS_ALIGN) % TCP_OPTS_ALIGN; return len; } always_inline int tcp_make_options (tcp_connection_t * tc, tcp_options_t * opts, tcp_state_t state) { switch (state) { case TCP_STATE_ESTABLISHED: case TCP_STATE_FIN_WAIT_1: return tcp_make_established_options (tc, opts); case TCP_STATE_SYN_RCVD: return tcp_make_synack_options (tc, opts); case TCP_STATE_SYN_SENT: return tcp_make_syn_options (opts, tc->rcv_wscale); default: clib_warning ("Not handled!"); return 0; } } /** * Update snd_mss to reflect the effective segment size that we can send * by taking into account all TCP options, including SACKs */ void tcp_update_snd_mss (tcp_connection_t * tc) { /* Compute options to be used for connection. These may be reused when * sending data or to compute the effective mss (snd_mss) */ tc->snd_opts_len = tcp_make_options (tc, &tc->snd_opts, TCP_STATE_ESTABLISHED); /* XXX check if MTU has been updated */ tc->snd_mss = clib_min (tc->mss, tc->rcv_opts.mss) - tc->snd_opts_len; ASSERT (tc->snd_mss > 0); } void tcp_init_mss (tcp_connection_t * tc) { u16 default_min_mss = 536; tcp_update_rcv_mss (tc); /* TODO cache mss and consider PMTU discovery */ tc->snd_mss = clib_min (tc->rcv_opts.mss, tc->mss); if (tc->snd_mss < 45) { clib_warning ("snd mss is 0"); /* Assume that at least the min default mss works */ tc->snd_mss = default_min_mss; tc->rcv_opts.mss = default_min_mss; } /* We should have enough space for 40 bytes of options */ ASSERT (tc->snd_mss > 45); /* If we use timestamp option, account for it */ if (tcp_opts_tstamp (&tc->rcv_opts)) tc->snd_mss -= TCP_OPTION_LEN_TIMESTAMP; } always_inline int tcp_alloc_tx_buffers (tcp_main_t * tm, u8 thread_index, u32 n_free_buffers) { vlib_main_t *vm = vlib_get_main (); u32 current_length = vec_len (tm->tx_buffers[thread_index]); u32 n_allocated; vec_validate (tm->tx_buffers[thread_index], current_length + n_free_buffers - 1); n_allocated = vlib_buffer_alloc (vm, &tm->tx_buffers[thread_index][current_length], n_free_buffers); _vec_len (tm->tx_buffers[thread_index]) = current_length + n_allocated; /* buffer shortage, report failure */ if (vec_len (tm->tx_buffers[thread_index]) == 0) { clib_warning ("out of buffers"); return -1; } return 0; } always_inline int tcp_get_free_buffer_index (tcp_main_t * tm, u32 * bidx) { u32 *my_tx_buffers; u32 thread_index = vlib_get_thread_index (); TCP_DBG_BUFFER_ALLOC_MAYBE_FAIL (thread_index); if (PREDICT_FALSE (vec_len (tm->tx_buffers[thread_index]) == 0)) { if (tcp_alloc_tx_buffers (tm, thread_index, VLIB_FRAME_SIZE)) return -1; } my_tx_buffers = tm->tx_buffers[thread_index]; *bidx = my_tx_buffers[vec_len (my_tx_buffers) - 1]; _vec_len (my_tx_buffers) -= 1; return 0; } always_inline void tcp_return_buffer (tcp_main_t * tm) { _vec_len (tm->tx_buffers[vlib_get_thread_index ()]) += 1; } always_inline void * tcp_reuse_buffer (vlib_main_t * vm, vlib_buffer_t * b) { if (b->flags & VLIB_BUFFER_NEXT_PRESENT) vlib_buffer_free_one (vm, b->next_buffer); /* Zero all flags but free list index and trace flag */ b->flags &= VLIB_BUFFER_NEXT_PRESENT - 1; 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 */ 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 &= VLIB_BUFFER_FREE_LIST_INDEX_MASK; b->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED; b->total_length_not_including_first_buffer = 0; vnet_buffer (b)->tcp.flags = 0; VLIB_BUFFER_TRACE_TRAJECTORY_INIT (b); /* Leave enough space for headers */ return vlib_buffer_make_headroom (b, MAX_HDRS_LEN); } /** * Prepare ACK */ void tcp_make_ack_i (tcp_connection_t * tc, vlib_buffer_t * b, tcp_state_t state, u8 flags) { tcp_options_t _snd_opts, *snd_opts = &_snd_opts; u8 tcp_opts_len, tcp_hdr_opts_len; tcp_header_t *th; u16 wnd; wnd = tcp_window_to_advertise (tc, state); /* Make and write options */ tcp_opts_len = tcp_make_established_options (tc, snd_opts); 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->snd_nxt, tc->rcv_nxt, tcp_hdr_opts_len, flags, wnd); tcp_options_write ((u8 *) (th + 1), snd_opts); vnet_buffer (b)->tcp.connection_index = tc->c_c_index; } /** * Convert buffer to ACK */ void tcp_make_ack (tcp_connection_t * tc, vlib_buffer_t * b) { vlib_main_t *vm = vlib_get_main (); tcp_reuse_buffer (vm, b); tcp_make_ack_i (tc, b, TCP_STATE_ESTABLISHED, TCP_FLAG_ACK); TCP_EVT_DBG (TCP_EVT_ACK_SENT, tc); vnet_buffer (b)->tcp.flags = TCP_BUF_FLAG_ACK; tc->rcv_las = tc->rcv_nxt; } /** * Convert buffer to FIN-ACK */ void tcp_make_fin (tcp_connection_t * tc, vlib_buffer_t * b) { vlib_main_t *vm = vlib_get_main (); u8 flags = 0; tcp_reuse_buffer (vm, b); flags = TCP_FLAG_FIN | TCP_FLAG_ACK; tcp_make_ack_i (tc, b, TCP_STATE_ESTABLISHED, flags); /* Reset flags, make sure ack is sent */ vnet_buffer (b)->tcp.flags &= ~TCP_BUF_FLAG_DUPACK; } /** * Convert buffer to SYN */ void tcp_make_syn (tcp_connection_t * tc, vlib_buffer_t * b) { u8 tcp_hdr_opts_len, tcp_opts_len; tcp_header_t *th; u16 initial_wnd; tcp_options_t snd_opts; initial_wnd = tcp_initial_window_to_advertise (tc); /* Make and write options */ memset (&snd_opts, 0, sizeof (snd_opts)); 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, tc->rcv_nxt, tcp_hdr_opts_len, TCP_FLAG_SYN, initial_wnd); vnet_buffer (b)->tcp.connection_index = tc->c_c_index; tcp_options_write ((u8 *) (th + 1), &snd_opts); } /** * Convert buffer to SYN-ACK */ void tcp_make_synack (tcp_connection_t * tc, vlib_buffer_t * b) { vlib_main_t *vm = vlib_get_main (); tcp_options_t _snd_opts, *snd_opts = &_snd_opts; u8 tcp_opts_len, tcp_hdr_opts_len; tcp_header_t *th; u16 initial_wnd; memset (snd_opts, 0, sizeof (*snd_opts)); tcp_reuse_buffer (vm, b); initial_wnd = tcp_initial_window_to_advertise (tc); tcp_opts_len = tcp_make_synack_options (tc, snd_opts); 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, tc->rcv_nxt, tcp_hdr_opts_len, TCP_FLAG_SYN | TCP_FLAG_ACK, initial_wnd); tcp_options_write ((u8 *) (th + 1), snd_opts); vnet_buffer (b)->tcp.connection_index = tc->c_c_index; vnet_buffer (b)->tcp.flags = TCP_BUF_FLAG_ACK; /* Init retransmit timer. Use update instead of set because of * retransmissions */ tcp_retransmit_timer_force_update (tc); TCP_EVT_DBG (TCP_EVT_SYNACK_SENT, tc); } always_inline void tcp_enqueue_to_ip_lookup_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; /* Default FIB for now */ vnet_buffer (b)->sw_if_index[VLIB_TX] = ~0; /* Send to IP lookup */ next_index = is_ip4 ? ip4_lookup_node.index : ip6_lookup_node.index; tcp_trajectory_add_start (b, 1); f = tm->ip_lookup_tx_frames[!is_ip4][thread_index]; if (!f) { f = vlib_get_frame_to_node (vm, next_index); ASSERT (f); tm->ip_lookup_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->ip_lookup_tx_frames[!is_ip4][thread_index] = 0; } } always_inline void tcp_enqueue_to_ip_lookup_now (vlib_main_t * vm, vlib_buffer_t * b, u32 bi, u8 is_ip4) { tcp_enqueue_to_ip_lookup_i (vm, b, bi, is_ip4, 1); } always_inline void tcp_enqueue_to_ip_lookup (vlib_main_t * vm, vlib_buffer_t * b, u32 bi, u8 is_ip4) { tcp_enqueue_to_ip_lookup_i (vm, b, bi, is_ip4, 0); } 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; tcp_trajectory_add_start (b, 2); /* 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) { ip4_header_t *ih4; ip6_header_t *ih6; tcp_header_t *th0; ip4_address_t src_ip40, dst_ip40; ip6_address_t src_ip60, dst_ip60; u16 src_port, dst_port; u32 tmp; u32 seq, ack; u8 flags; /* Find IP and TCP headers */ th0 = tcp_buffer_hdr (b0); /* Save src and dst ip */ if (is_ip4) { ih4 = vlib_buffer_get_current (b0); ASSERT ((ih4->ip_version_and_header_length & 0xF0) == 0x40); src_ip40.as_u32 = ih4->src_address.as_u32; dst_ip40.as_u32 = ih4->dst_address.as_u32; } else { ih6 = vlib_buffer_get_current (b0); ASSERT ((ih6->ip_version_traffic_class_and_flow_label & 0xF0) == 0x60); clib_memcpy (&src_ip60, &ih6->src_address, sizeof (ip6_address_t)); clib_memcpy (&dst_ip60, &ih6->dst_address, sizeof (ip6_address_t)); } src_port = th0->src_port; dst_port = th0->dst_port; /* Try to determine what/why we're actually resetting */ if (state == TCP_STATE_CLOSED) { if (!tcp_syn (th0)) return -1; tmp = clib_net_to_host_u32 (th0->seq_number); /* Got a SYN for no listener. */ flags = TCP_FLAG_RST | TCP_FLAG_ACK; ack = clib_host_to_net_u32 (tmp + 1); seq = 0; } else { flags = TCP_FLAG_RST; seq = th0->ack_number; ack = 0; } tcp_reuse_buffer (vm, b0); tcp_trajectory_add_start (b0, 4); th0 = vlib_buffer_push_tcp_net_order (b0, dst_port, src_port, seq, ack, sizeof (tcp_header_t), flags, 0); if (is_ip4) { ih4 = vlib_buffer_push_ip4 (vm, b0, &dst_ip40, &src_ip40, IP_PROTOCOL_TCP, 1); th0->checksum = ip4_tcp_udp_compute_checksum (vm, b0, ih4); } else { int bogus = ~0; ih6 = vlib_buffer_push_ip6 (vm, b0, &dst_ip60, &src_ip60, IP_PROTOCOL_TCP); th0->checksum = ip6_tcp_udp_icmp_compute_checksum (vm, b0, ih6, &bogus); ASSERT (!bogus); } return 0; } /** * Send reset without reusing existing buffer * * It extracts connection info out of original packet */ void tcp_send_reset_w_pkt (tcp_connection_t * tc, vlib_buffer_t * pkt, u8 is_ip4) { vlib_buffer_t *b; u32 bi; tcp_main_t *tm = vnet_get_tcp_main (); vlib_main_t *vm = vlib_get_main (); u8 tcp_hdr_len, flags = 0; tcp_header_t *th, *pkt_th; u32 seq, ack; ip4_header_t *ih4, *pkt_ih4; ip6_header_t *ih6, *pkt_ih6; if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi))) return; b = vlib_get_buffer (vm, bi); tcp_init_buffer (vm, b); /* Make and write options */ tcp_hdr_len = sizeof (tcp_header_t); if (is_ip4) { pkt_ih4 = vlib_buffer_get_current (pkt); pkt_th = ip4_next_header (pkt_ih4); } else { pkt_ih6 = vlib_buffer_get_current (pkt); pkt_th = ip6_next_header (pkt_ih6); } if (tcp_ack (pkt_th)) { flags = TCP_FLAG_RST; seq = pkt_th->ack_number; ack = (tc && tc->state >= TCP_STATE_SYN_RCVD) ? tc->rcv_nxt : 0; } else { flags = TCP_FLAG_RST | TCP_FLAG_ACK; seq = 0; ack = clib_host_to_net_u32 (vnet_buffer (pkt)->tcp.seq_end); } th = vlib_buffer_push_tcp_net_order (b, pkt_th->dst_port, pkt_th->src_port, seq, ack, tcp_hdr_len, flags, 0); /* Swap src and dst ip */ if (is_ip4) { ASSERT ((pkt_ih4->ip_version_and_header_length & 0xF0) == 0x40); ih4 = vlib_buffer_push_ip4 (vm, b, &pkt_ih4->dst_address, &pkt_ih4->src_address, IP_PROTOCOL_TCP, 1); th->checksum = ip4_tcp_udp_compute_checksum (vm, b, ih4); } else { int bogus = ~0; ASSERT ((pkt_ih6->ip_version_traffic_class_and_flow_label & 0xF0) == 0x60); ih6 = vlib_buffer_push_ip6 (vm, b, &pkt_ih6->dst_address, &pkt_ih6->src_address, IP_PROTOCOL_TCP); th->checksum = ip6_tcp_udp_icmp_compute_checksum (vm, b, ih6, &bogus); ASSERT (!bogus); } tcp_enqueue_to_ip_lookup_now (vm, b, bi, 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; if (tc->c_is_ip4) { ip4_header_t *ih4; ih4 = vlib_buffer_push_ip4 (vm, b, &tc->c_lcl_ip.ip4, &tc->c_rmt_ip.ip4, IP_PROTOCOL_TCP, 0); th->checksum = ip4_tcp_udp_compute_checksum (vm, b, ih4); } else { int bogus = ~0; ip6_header_t *ih6; ih6 = vlib_buffer_push_ip6 (vm, b, &tc->c_lcl_ip.ip6, &tc->c_rmt_ip.ip6, IP_PROTOCOL_TCP); th->checksum = ip6_tcp_udp_icmp_compute_checksum (vm, b, ih6, &bogus); ASSERT (!bogus); } tcp_enqueue_to_ip_lookup_now (vm, b, bi, tc->c_is_ip4); TCP_EVT_DBG (TCP_EVT_RST_SENT, tc); } void tcp_push_ip_hdr (tcp_main_t * tm, tcp_connection_t * tc, vlib_buffer_t * b) { tcp_header_t *th = vlib_buffer_get_current (b); vlib_main_t *vm = vlib_get_main (); if (tc->c_is_ip4) { ip4_header_t *ih; ih = vlib_buffer_push_ip4 (vm, b, &tc->c_lcl_ip4, &tc->c_rmt_ip4, IP_PROTOCOL_TCP, 1); th->checksum = ip4_tcp_udp_compute_checksum (vm, b, ih); } else { ip6_header_t *ih; int bogus = ~0; ih = vlib_buffer_push_ip6 (vm, b, &tc->c_lcl_ip6, &tc->c_rmt_ip6, IP_PROTOCOL_TCP); th->checksum = ip6_tcp_udp_icmp_compute_checksum (vm, b, ih, &bogus); ASSERT (!bogus); } } /** * Send SYN * * Builds a SYN packet for a half-open connection and sends it to ipx_lookup. * The packet is not forwarded through tcpx_output to avoid doing lookups * in the half_open pool. */ void tcp_send_syn (tcp_connection_t * tc) { vlib_buffer_t *b; u32 bi; tcp_main_t *tm = vnet_get_tcp_main (); vlib_main_t *vm = vlib_get_main (); /* * Setup retransmit and establish timers before requesting buffer * such that we can return if we've ran out. */ tcp_timer_set (tc, TCP_TIMER_ESTABLISH, TCP_ESTABLISH_TIME); tcp_timer_update (tc, TCP_TIMER_RETRANSMIT_SYN, tc->rto * TCP_TO_TIMER_TICK); if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi))) return; b = vlib_get_buffer (vm, bi); tcp_init_buffer (vm, b); tcp_make_syn (tc, b); /* Measure RTT with this */ tc->rtt_ts = tcp_time_now (); tc->rtt_seq = tc->snd_nxt; tc->rto_boff = 0; tcp_push_ip_hdr (tm, tc, b); tcp_enqueue_to_ip_lookup (vm, b, bi, tc->c_is_ip4); TCP_EVT_DBG (TCP_EVT_SYN_SENT, tc); } /** * Flush tx frame populated by retransmits and timer pops */ void tcp_flush_frame_to_output (vlib_main_t * vm, u8 thread_index, u8 is_ip4) { if (tcp_main.tx_frames[!is_ip4][thread_index]) { u32 next_index; next_index = is_ip4 ? tcp4_output_node.index : tcp6_output_node.index; vlib_put_frame_to_node (vm, next_index, tcp_main.tx_frames[!is_ip4][thread_index]); tcp_main.tx_frames[!is_ip4][thread_index] = 0; } } /** * Flush ip lookup tx frames populated by timer pops */ always_inline void tcp_flush_frame_to_ip_lookup (vlib_main_t * vm, u8 thread_index, u8 is_ip4) { if (tcp_main.ip_lookup_tx_frames[!is_ip4][thread_index]) { u32 next_index; next_index = is_ip4 ? ip4_lookup_node.index : ip6_lookup_node.index; vlib_put_frame_to_node (vm, next_index, tcp_main.ip_lookup_tx_frames[!is_ip4] [thread_index]); tcp_main.ip_lookup_tx_frames[!is_ip4][thread_index] = 0; } } /** * Flush v4 and v6 tcp and ip-lookup tx frames for thread index */ void tcp_flush_frames_to_output (u8 thread_index) { vlib_main_t *vm = vlib_get_main (); tcp_flush_frame_to_output (vm, thread_index, 1); tcp_flush_frame_to_output (vm, thread_index, 0); tcp_flush_frame_to_ip_lookup (vm, thread_index, 1); tcp_flush_frame_to_ip_lookup (vm, thread_index, 0); } /** * Send FIN */ void tcp_send_fin (tcp_connection_t * tc) { tcp_main_t *tm = vnet_get_tcp_main (); vlib_main_t *vm = vlib_get_main (); vlib_buffer_t *b; u32 bi; u8 fin_snt = 0; tcp_retransmit_timer_force_update (tc); if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi))) return; b = vlib_get_buffer (vm, bi); fin_snt = tc->flags & TCP_CONN_FINSNT; if (fin_snt) tc->snd_nxt = tc->snd_una; tcp_make_fin (tc, b); tcp_enqueue_to_output_now (vm, b, bi, tc->c_is_ip4); if (!fin_snt) { tc->flags |= TCP_CONN_FINSNT; tc->flags &= ~TCP_CONN_FINPNDG; /* Account for the FIN */ tc->snd_una_max += 1; tc->snd_nxt = tc->snd_una_max; } else { tc->snd_nxt = tc->snd_una_max; } TCP_EVT_DBG (TCP_EVT_FIN_SENT, tc); } always_inline u8 tcp_make_state_flags (tcp_connection_t * tc, tcp_state_t next_state) { switch (next_state) { case TCP_STATE_ESTABLISHED: return TCP_FLAG_ACK; case TCP_STATE_SYN_RCVD: return TCP_FLAG_SYN | TCP_FLAG_ACK; case TCP_STATE_SYN_SENT: return TCP_FLAG_SYN; case TCP_STATE_LAST_ACK: case TCP_STATE_FIN_WAIT_1: if (tc->snd_nxt + 1 < tc->snd_una_max) return TCP_FLAG_ACK; else return TCP_FLAG_FIN; default: clib_warning ("Shouldn't be here!"); } return 0; } /** * Push TCP header and update connection variables */ static void tcp_push_hdr_i (tcp_connection_t * tc, vlib_buffer_t * b, tcp_state_t next_state, u8 compute_opts) { u32 advertise_wnd, data_len; u8 tcp_hdr_opts_len, opts_write_len, flags; 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) 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, next_state); flags = tcp_make_state_flags (tc, next_state); /* Push header and options */ 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; /* * Update connection variables */ tc->snd_nxt += data_len; tc->rcv_las = tc->rcv_nxt; /* TODO this is updated in output as well ... */ if (seq_gt (tc->snd_nxt, tc->snd_una_max)) { tc->snd_una_max = tc->snd_nxt; tcp_validate_txf_size (tc, tc->snd_una_max - tc->snd_una); } TCP_EVT_DBG (TCP_EVT_PKTIZE, tc); } void tcp_send_ack (tcp_connection_t * tc) { tcp_main_t *tm = vnet_get_tcp_main (); vlib_main_t *vm = vlib_get_main (); vlib_buffer_t *b; u32 bi; /* Get buffer */ if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi))) return; b = vlib_get_buffer (vm, bi); /* Fill in the ACK */ tcp_make_ack (tc, b); tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4); } /** * Delayed ack timer handler * * Sends delayed ACK when timer expires */ void tcp_timer_delack_handler (u32 index) { u32 thread_index = vlib_get_thread_index (); tcp_connection_t *tc; tc = tcp_connection_get (index, thread_index); tc->timers[TCP_TIMER_DELACK] = TCP_TIMER_HANDLE_INVALID; tcp_send_ack (tc); } /** * Build a retransmit segment * * @return the number of bytes in the segment or 0 if there's nothing to * retransmit */ u32 tcp_prepare_retransmit_segment (tcp_connection_t * tc, u32 offset, u32 max_deq_bytes, vlib_buffer_t ** b) { tcp_main_t *tm = vnet_get_tcp_main (); vlib_main_t *vm = vlib_get_main (); int n_bytes = 0; u32 start, bi, available_bytes, seg_size; u8 *data; ASSERT (tc->state >= TCP_STATE_ESTABLISHED); ASSERT (max_deq_bytes != 0); /* * Make sure we can retransmit something */ available_bytes = stream_session_tx_fifo_max_dequeue (&tc->connection); ASSERT (available_bytes >= offset); 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); /* Start is beyond snd_congestion */ start = tc->snd_una + offset; if (seq_geq (start, tc->snd_congestion)) 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; } seg_size = max_deq_bytes + MAX_HDRS_LEN; /* * Prepare options */ tc->snd_opts_len = tcp_make_options (tc, &tc->snd_opts, tc->state); /* * Allocate and fill in buffer(s) */ if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi))) return 0; *b = vlib_get_buffer (vm, bi); data = tcp_init_buffer (vm, *b); /* Easy case, buffer size greater than mss */ if (PREDICT_TRUE (seg_size <= tm->bytes_per_buffer)) { n_bytes = stream_session_peek_bytes (&tc->connection, data, offset, max_deq_bytes); ASSERT (n_bytes == max_deq_bytes); b[0]->current_length = n_bytes; tcp_push_hdr_i (tc, *b, tc->state, 0); } /* Split mss into multiple buffers */ else { u32 chain_bi = ~0, n_bufs_per_seg; u32 thread_index = vlib_get_thread_index (); u16 n_peeked, len_to_deq, available_bufs; vlib_buffer_t *chain_b, *prev_b; int i; n_bufs_per_seg = ceil ((double) seg_size / tm->bytes_per_buffer); /* Make sure we have enough buffers */ available_bufs = vec_len (tm->tx_buffers[thread_index]); if (n_bufs_per_seg > available_bufs) { if (tcp_alloc_tx_buffers (tm, thread_index, VLIB_FRAME_SIZE - available_bufs)) { tcp_return_buffer (tm); *b = 0; return 0; } } n_bytes = stream_session_peek_bytes (&tc->connection, data, offset, tm->bytes_per_buffer - MAX_HDRS_LEN); b[0]->current_length = n_bytes; b[0]->flags |= VLIB_BUFFER_TOTAL_LENGTH_VALID; b[0]->total_length_not_including_first_buffer = 0; max_deq_bytes -= n_bytes; chain_b = *b; for (i = 1; i < n_bufs_per_seg; i++) { prev_b = chain_b; len_to_deq = clib_min (max_deq_bytes, tm->bytes_per_buffer); tcp_get_free_buffer_index (tm, &chain_bi); ASSERT (chain_bi != (u32) ~ 0); chain_b = vlib_get_buffer (vm, chain_bi); chain_b->current_data = 0; data = vlib_buffer_get_current (chain_b); n_peeked = stream_session_peek_bytes (&tc->connection, data, offset + n_bytes, len_to_deq); ASSERT (n_peeked == len_to_deq); n_bytes += n_peeked; chain_b->current_length = n_peeked; chain_b->flags &= VLIB_BUFFER_FREE_LIST_INDEX_MASK; chain_b->next_buffer = 0; /* update previous buffer */ prev_b->next_buffer = chain_bi; prev_b->flags |= VLIB_BUFFER_NEXT_PRESENT; 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); ASSERT (((*b)->current_data + (*b)->current_length) <= tm->bytes_per_buffer); if (tcp_in_fastrecovery (tc)) tc->snd_rxt_bytes += n_bytes; done: TCP_EVT_DBG (TCP_EVT_CC_RTX, tc, offset, n_bytes); return n_bytes; } /** * Reset congestion control, switch cwnd to loss window and try again. */ static void tcp_rtx_timeout_cc (tcp_connection_t * tc) { tc->prev_ssthresh = tc->ssthresh; tc->prev_cwnd = tc->cwnd; /* Cleanly recover cc (also clears up fast retransmit) */ if (tcp_in_fastrecovery (tc)) tcp_cc_fastrecovery_exit (tc); /* Start again from the beginning */ tc->ssthresh = clib_max (tcp_flight_size (tc) / 2, 2 * tc->snd_mss); tc->cwnd = tcp_loss_wnd (tc); tc->snd_congestion = tc->snd_una_max; tc->rtt_ts = 0; tcp_recovery_on (tc); } static void tcp_timer_retransmit_handler_i (u32 index, u8 is_syn) { tcp_main_t *tm = vnet_get_tcp_main (); vlib_main_t *vm = vlib_get_main (); u32 thread_index = vlib_get_thread_index (); tcp_connection_t *tc; vlib_buffer_t *b = 0; u32 bi, n_bytes; if (is_syn) { tc = tcp_half_open_connection_get (index); /* Note: the connection may have transitioned to ESTABLISHED... */ if (PREDICT_FALSE (tc == 0)) return; tc->timers[TCP_TIMER_RETRANSMIT_SYN] = TCP_TIMER_HANDLE_INVALID; } else { tc = tcp_connection_get (index, thread_index); /* Note: the connection may have been closed and pool_put */ if (PREDICT_FALSE (tc == 0)) return; tc->timers[TCP_TIMER_RETRANSMIT] = TCP_TIMER_HANDLE_INVALID; } if (tc->state >= TCP_STATE_ESTABLISHED) { /* Lost FIN, retransmit and return */ if (tcp_is_lost_fin (tc)) { tcp_send_fin (tc); tc->rto_boff += 1; tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX); return; } /* Shouldn't be here */ if (tc->snd_una == tc->snd_una_max) { tcp_recovery_off (tc); return; } /* We're not in recovery so make sure rto_boff is 0 */ if (!tcp_in_recovery (tc) && tc->rto_boff > 0) { tc->rto_boff = 0; tcp_update_rto (tc); } /* Increment RTO backoff (also equal to number of retries) and go back * to first un-acked byte */ tc->rto_boff += 1; /* First retransmit timeout */ if (tc->rto_boff == 1) tcp_rtx_timeout_cc (tc); tc->snd_nxt = tc->snd_una; tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX); TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 1); /* Send one segment. Note that n_bytes may be zero due to buffer shortfall */ n_bytes = tcp_prepare_retransmit_segment (tc, 0, tc->snd_mss, &b); /* TODO be less aggressive about this */ scoreboard_clear (&tc->sack_sb); if (n_bytes == 0) { tcp_retransmit_timer_set (tc); return; } bi = vlib_get_buffer_index (vm, b); /* For first retransmit, record timestamp (Eifel detection RFC3522) */ if (tc->rto_boff == 1) tc->snd_rxt_ts = tcp_time_now (); tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4); tcp_retransmit_timer_update (tc); } /* Retransmit for SYN */ else if (tc->state == TCP_STATE_SYN_SENT) { /* Half-open connection actually moved to established but we were * waiting for syn retransmit to pop to call cleanup from the right * thread. */ if (tc->flags & TCP_CONN_HALF_OPEN_DONE) { if (tcp_half_open_connection_cleanup (tc)) { clib_warning ("could not remove half-open connection"); ASSERT (0); } return; } /* Try without increasing RTO a number of times. If this fails, * start growing RTO exponentially */ tc->rto_boff += 1; if (tc->rto_boff > TCP_RTO_SYN_RETRIES) tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX); tcp_timer_update (tc, TCP_TIMER_RETRANSMIT_SYN, tc->rto * TCP_TO_TIMER_TICK); if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi))) return; b = vlib_get_buffer (vm, bi); tcp_init_buffer (vm, b); tcp_make_syn (tc, b); tc->rtt_ts = 0; TCP_EVT_DBG (TCP_EVT_SYN_RXT, tc, 0); /* This goes straight to ipx_lookup. Retransmit timer set already */ tcp_push_ip_hdr (tm, tc, b); tcp_enqueue_to_ip_lookup (vm, b, bi, tc->c_is_ip4); } /* Retransmit SYN-ACK */ else if (tc->state == TCP_STATE_SYN_RCVD) { tc->rto_boff += 1; if (tc->rto_boff > TCP_RTO_SYN_RETRIES) tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX); tc->rtt_ts = 0; if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi))) { tcp_retransmit_timer_force_update (tc); return; } b = vlib_get_buffer (vm, bi); tcp_make_synack (tc, b); TCP_EVT_DBG (TCP_EVT_SYN_RXT, tc, 1); /* Retransmit timer already updated, just enqueue to output */ tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4); } else { ASSERT (tc->state == TCP_STATE_CLOSED); return; } } void tcp_timer_retransmit_handler (u32 index) { tcp_timer_retransmit_handler_i (index, 0); } void tcp_timer_retransmit_syn_handler (u32 index) { tcp_timer_retransmit_handler_i (index, 1); } /** * Got 0 snd_wnd from peer, try to do something about it. * */ void tcp_timer_persist_handler (u32 index) { tcp_main_t *tm = vnet_get_tcp_main (); vlib_main_t *vm = vlib_get_main (); u32 thread_index = vlib_get_thread_index (); tcp_connection_t *tc; vlib_buffer_t *b; u32 bi, max_snd_bytes, available_bytes, offset; int n_bytes = 0; u8 *data; tc = tcp_connection_get_if_valid (index, thread_index); if (!tc) return; /* Make sure timer handle is set to invalid */ tc->timers[TCP_TIMER_PERSIST] = TCP_TIMER_HANDLE_INVALID; /* Problem already solved or worse */ if (tc->state == TCP_STATE_CLOSED || tc->state > TCP_STATE_ESTABLISHED || tc->snd_wnd > tc->snd_mss || tcp_in_recovery (tc)) return; available_bytes = stream_session_tx_fifo_max_dequeue (&tc->connection); offset = tc->snd_una_max - tc->snd_una; /* Reprogram persist if no new bytes available to send. We may have data * next time */ if (!available_bytes) { tcp_persist_timer_set (tc); return; } if (available_bytes <= offset) { ASSERT (tcp_timer_is_active (tc, TCP_TIMER_RETRANSMIT)); return; } /* Increment RTO backoff */ tc->rto_boff += 1; tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX); /* * Try to force the first unsent segment (or buffer) */ 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, offset); tc->snd_opts_len = tcp_make_options (tc, &tc->snd_opts, tc->state); 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 (n_bytes != 0 && (tcp_timer_is_active (tc, TCP_TIMER_RETRANSMIT) || tc->snd_nxt == tc->snd_una_max || tc->rto_boff > 1)); tcp_push_hdr_i (tc, b, tc->state, 0); tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4); /* Just sent new data, enable retransmit */ tcp_retransmit_timer_update (tc); } /** * Retransmit first unacked segment */ void tcp_retransmit_first_unacked (tcp_connection_t * tc) { vlib_main_t *vm = vlib_get_main (); vlib_buffer_t *b; u32 bi, old_snd_nxt, n_bytes; old_snd_nxt = tc->snd_nxt; tc->snd_nxt = tc->snd_una; TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 2); n_bytes = tcp_prepare_retransmit_segment (tc, 0, tc->snd_mss, &b); if (!n_bytes) return; bi = vlib_get_buffer_index (vm, b); tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4); tc->snd_nxt = old_snd_nxt; } /** * Do fast retransmit with SACKs */ void tcp_fast_retransmit_sack (tcp_connection_t * tc) { vlib_main_t *vm = vlib_get_main (); u32 n_written = 0, offset, max_bytes; vlib_buffer_t *b = 0; sack_scoreboard_hole_t *hole; sack_scoreboard_t *sb; u32 bi, old_snd_nxt; int snd_space; u8 snd_limited = 0, can_rescue = 0; ASSERT (tcp_in_fastrecovery (tc)); TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 0); old_snd_nxt = tc->snd_nxt; sb = &tc->sack_sb; snd_space = tcp_available_snd_space (tc); hole = scoreboard_get_hole (sb, sb->cur_rxt_hole); while (hole && snd_space > 0) { hole = scoreboard_next_rxt_hole (sb, hole, tcp_fastrecovery_sent_1_smss (tc), &can_rescue, &snd_limited); if (!hole) { if (!can_rescue || !(seq_lt (sb->rescue_rxt, tc->snd_una) || seq_gt (sb->rescue_rxt, tc->snd_congestion))) break; /* If rescue rxt undefined or less than snd_una then one segment of * up to SMSS octets that MUST include the highest outstanding * unSACKed sequence number SHOULD be returned, and RescueRxt set to * RecoveryPoint. HighRxt MUST NOT be updated. */ 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; n_written = tcp_prepare_retransmit_segment (tc, offset, max_bytes, &b); ASSERT (n_written); bi = vlib_get_buffer_index (vm, b); tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4); break; } 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 = sb->high_rxt; n_written = tcp_prepare_retransmit_segment (tc, offset, max_bytes, &b); /* Nothing left to retransmit */ if (n_written == 0) break; 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; } /* If window allows, send 1 SMSS of new data */ tc->snd_nxt = old_snd_nxt; } /** * Fast retransmit without SACK info */ void tcp_fast_retransmit_no_sack (tcp_connection_t * tc) { vlib_main_t *vm = vlib_get_main (); u32 n_written = 0, offset = 0, bi, old_snd_nxt; int snd_space; vlib_buffer_t *b; ASSERT (tcp_in_fastrecovery (tc)); TCP_EVT_DBG (TCP_EVT_CC_EVT, tc, 0); /* Start resending from first un-acked segment */ old_snd_nxt = tc->snd_nxt; tc->snd_nxt = tc->snd_una; snd_space = tcp_available_snd_space (tc); while (snd_space > 0) { offset += n_written; n_written = tcp_prepare_retransmit_segment (tc, offset, snd_space, &b); /* Nothing left to retransmit */ if (n_written == 0) break; bi = vlib_get_buffer_index (vm, b); tcp_enqueue_to_output (vm, b, bi, tc->c_is_ip4); snd_space -= n_written; } /* Restore snd_nxt. If window allows, send 1 SMSS of new data */ tc->snd_nxt = old_snd_nxt; } /** * Do fast retransmit */ void tcp_fast_retransmit (tcp_connection_t * tc) { if (tcp_opts_sack_permitted (&tc->rcv_opts) && scoreboard_first_hole (&tc->sack_sb)) tcp_fast_retransmit_sack (tc); else tcp_fast_retransmit_no_sack (tc); } always_inline u32 tcp_session_has_ooo_data (tcp_connection_t * tc) { stream_session_t *s = session_get (tc->c_s_index, tc->c_thread_index); return svm_fifo_has_ooo_data (s->server_rx_fifo); } always_inline uword tcp46_output_inline (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * from_frame, int is_ip4) { u32 n_left_from, next_index, *from, *to_next; u32 my_thread_index = vm->thread_index; from = vlib_frame_vector_args (from_frame); n_left_from = from_frame->n_vectors; next_index = node->cached_next_index; tcp_set_time_now (my_thread_index); while (n_left_from > 0) { u32 n_left_to_next; vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next); while (n_left_from > 0 && n_left_to_next > 0) { u32 bi0; vlib_buffer_t *b0; tcp_connection_t *tc0; tcp_tx_trace_t *t0; tcp_header_t *th0 = 0; u32 error0 = TCP_ERROR_PKTS_SENT, next0 = TCP_OUTPUT_NEXT_IP_LOOKUP; bi0 = from[0]; to_next[0] = bi0; from += 1; to_next += 1; n_left_from -= 1; n_left_to_next -= 1; b0 = vlib_get_buffer (vm, bi0); tc0 = tcp_connection_get (vnet_buffer (b0)->tcp.connection_index, my_thread_index); if (PREDICT_FALSE (tc0 == 0 || tc0->state == TCP_STATE_CLOSED)) { error0 = TCP_ERROR_INVALID_CONNECTION; next0 = TCP_OUTPUT_NEXT_DROP; goto done; } th0 = vlib_buffer_get_current (b0); TCP_EVT_DBG (TCP_EVT_OUTPUT, tc0, th0->flags, b0->current_length); if (is_ip4) { vlib_buffer_push_ip4 (vm, b0, &tc0->c_lcl_ip4, &tc0->c_rmt_ip4, IP_PROTOCOL_TCP, 1); b0->flags |= VNET_BUFFER_F_OFFLOAD_TCP_CKSUM; vnet_buffer (b0)->l4_hdr_offset = (u8 *) th0 - b0->data; th0->checksum = 0; } else { ip6_header_t *ih0; ih0 = vlib_buffer_push_ip6 (vm, b0, &tc0->c_lcl_ip6, &tc0->c_rmt_ip6, IP_PROTOCOL_TCP); b0->flags |= VNET_BUFFER_F_OFFLOAD_TCP_CKSUM; vnet_buffer (b0)->l3_hdr_offset = (u8 *) ih0 - b0->data; vnet_buffer (b0)->l4_hdr_offset = (u8 *) th0 - b0->data; th0->checksum = 0; } /* Filter out DUPACKs if there are no OOO segments left */ if (PREDICT_FALSE (vnet_buffer (b0)->tcp.flags & TCP_BUF_FLAG_DUPACK)) { if (!tcp_session_has_ooo_data (tc0)) { error0 = TCP_ERROR_FILTERED_DUPACKS; next0 = TCP_OUTPUT_NEXT_DROP; goto done; } } /* Stop DELACK timer and fix flags */ tc0->flags &= ~(TCP_CONN_SNDACK); tcp_timer_reset (tc0, TCP_TIMER_DELACK); /* If not retransmitting * 1) update snd_una_max (SYN, SYNACK, FIN) * 2) If we're not tracking an ACK, start tracking */ if (seq_lt (tc0->snd_una_max, tc0->snd_nxt)) { tc0->snd_una_max = tc0->snd_nxt; if (tc0->rtt_ts == 0) { tc0->rtt_ts = tcp_time_now (); tc0->rtt_seq = tc0->snd_nxt; } } /* Set the retransmit timer if not set already and not * doing a pure ACK */ if (!tcp_timer_is_active (tc0, TCP_TIMER_RETRANSMIT) && tc0->snd_nxt != tc0->snd_una) { tcp_retransmit_timer_set (tc0); tc0->rto_boff = 0; } #if 0 /* Make sure we haven't lost route to our peer */ if (PREDICT_FALSE (tc0->last_fib_check < tc0->snd_opts.tsval + TCP_FIB_RECHECK_PERIOD)) { if (PREDICT_TRUE (tc0->c_rmt_fei == tcp_lookup_rmt_in_fib (tc0))) { tc0->last_fib_check = tc0->snd_opts.tsval; } else { clib_warning ("lost connection to peer"); tcp_connection_reset (tc0); goto done; } } /* Use pre-computed dpo to set next node */ next0 = tc0->c_rmt_dpo.dpoi_next_node; vnet_buffer (b0)->ip.adj_index[VLIB_TX] = tc0->c_rmt_dpo.dpoi_index; #endif vnet_buffer (b0)->sw_if_index[VLIB_RX] = 0; vnet_buffer (b0)->sw_if_index[VLIB_TX] = ~0; b0->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED; done: b0->error = node->errors[error0]; if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED)) { t0 = vlib_add_trace (vm, node, b0, sizeof (*t0)); if (th0) { clib_memcpy (&t0->tcp_header, th0, sizeof (t0->tcp_header)); } else { memset (&t0->tcp_header, 0, sizeof (t0->tcp_header)); } clib_memcpy (&t0->tcp_connection, tc0, sizeof (t0->tcp_connection)); } vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next, n_left_to_next, bi0, next0); } vlib_put_next_frame (vm, node, next_index, n_left_to_next); } return from_frame->n_vectors; } static uword tcp4_output (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * from_frame) { return tcp46_output_inline (vm, node, from_frame, 1 /* is_ip4 */ ); } static uword tcp6_output (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * from_frame) { return tcp46_output_inline (vm, node, from_frame, 0 /* is_ip4 */ ); } /* *INDENT-OFF* */ VLIB_REGISTER_NODE (tcp4_output_node) = { .function = tcp4_output,.name = "tcp4-output", /* Takes a vector of packets. */ .vector_size = sizeof (u32), .n_errors = TCP_N_ERROR, .error_strings = tcp_error_strings, .n_next_nodes = TCP_OUTPUT_N_NEXT, .next_nodes = { #define _(s,n) [TCP_OUTPUT_NEXT_##s] = n, foreach_tcp4_output_next #undef _ }, .format_buffer = format_tcp_header, .format_trace = format_tcp_tx_trace, }; /* *INDENT-ON* */ VLIB_NODE_FUNCTION_MULTIARCH (tcp4_output_node, tcp4_output); /* *INDENT-OFF* */ VLIB_REGISTER_NODE (tcp6_output_node) = { .function = tcp6_output, .name = "tcp6-output", /* Takes a vector of packets. */ .vector_size = sizeof (u32), .n_errors = TCP_N_ERROR, .error_strings = tcp_error_strings, .n_next_nodes = TCP_OUTPUT_N_NEXT, .next_nodes = { #define _(s,n) [TCP_OUTPUT_NEXT_##s] = n, foreach_tcp6_output_next #undef _ }, .format_buffer = format_tcp_header, .format_trace = format_tcp_tx_trace, }; /* *INDENT-ON* */ VLIB_NODE_FUNCTION_MULTIARCH (tcp6_output_node, tcp6_output); u32 tcp_push_header (transport_connection_t * tconn, vlib_buffer_t * b) { tcp_connection_t *tc; 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)) { tc->rtt_ts = tcp_time_now (); tc->rtt_seq = tc->snd_nxt; } tcp_trajectory_add_start (b, 3); return 0; } typedef enum _tcp_reset_next { TCP_RESET_NEXT_DROP, TCP_RESET_NEXT_IP_LOOKUP, TCP_RESET_N_NEXT } tcp_reset_next_t; #define foreach_tcp4_reset_next \ _(DROP, "error-drop") \ _(IP_LOOKUP, "ip4-lookup") #define foreach_tcp6_reset_next \ _(DROP, "error-drop") \ _(IP_LOOKUP, "ip6-lookup") static uword tcp46_send_reset_inline (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * from_frame, u8 is_ip4) { u32 n_left_from, next_index, *from, *to_next; u32 my_thread_index = vm->thread_index; from = vlib_frame_vector_args (from_frame); n_left_from = from_frame->n_vectors; next_index = node->cached_next_index; while (n_left_from > 0) { u32 n_left_to_next; vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next); while (n_left_from > 0 && n_left_to_next > 0) { u32 bi0; vlib_buffer_t *b0; tcp_tx_trace_t *t0; tcp_header_t *th0; u32 error0 = TCP_ERROR_RST_SENT, next0 = TCP_RESET_NEXT_IP_LOOKUP; bi0 = from[0]; to_next[0] = bi0; from += 1; to_next += 1; n_left_from -= 1; n_left_to_next -= 1; b0 = vlib_get_buffer (vm, bi0); if (tcp_make_reset_in_place (vm, b0, vnet_buffer (b0)->tcp.flags, my_thread_index, is_ip4)) { error0 = TCP_ERROR_LOOKUP_DROPS; next0 = TCP_RESET_NEXT_DROP; goto done; } /* Prepare to send to IP lookup */ vnet_buffer (b0)->sw_if_index[VLIB_TX] = ~0; next0 = TCP_RESET_NEXT_IP_LOOKUP; done: b0->error = node->errors[error0]; b0->flags |= VNET_BUFFER_F_LOCALLY_ORIGINATED; if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED)) { th0 = vlib_buffer_get_current (b0); if (is_ip4) th0 = ip4_next_header ((ip4_header_t *) th0); else th0 = ip6_next_header ((ip6_header_t *) th0); t0 = vlib_add_trace (vm, node, b0, sizeof (*t0)); clib_memcpy (&t0->tcp_header, th0, sizeof (t0->tcp_header)); } vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next, n_left_to_next, bi0, next0); } vlib_put_next_frame (vm, node, next_index, n_left_to_next); } return from_frame->n_vectors; } static uword tcp4_send_reset (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * from_frame) { return tcp46_send_reset_inline (vm, node, from_frame, 1); } static uword tcp6_send_reset (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * from_frame) { return tcp46_send_reset_inline (vm, node, from_frame, 0); } /* *INDENT-OFF* */ VLIB_REGISTER_NODE (tcp4_reset_node) = { .function = tcp4_send_reset, .name = "tcp4-reset", .vector_size = sizeof (u32), .n_errors = TCP_N_ERROR, .error_strings = tcp_error_strings, .n_next_nodes = TCP_RESET_N_NEXT, .next_nodes = { #define _(s,n) [TCP_RESET_NEXT_##s] = n, foreach_tcp4_reset_next #undef _ }, .format_trace = format_tcp_tx_trace, }; /* *INDENT-ON* */ VLIB_NODE_FUNCTION_MULTIARCH (tcp4_reset_node, tcp4_send_reset); /* *INDENT-OFF* */ VLIB_REGISTER_NODE (tcp6_reset_node) = { .function = tcp6_send_reset, .name = "tcp6-reset", .vector_size = sizeof (u32), .n_errors = TCP_N_ERROR, .error_strings = tcp_error_strings, .n_next_nodes = TCP_RESET_N_NEXT, .next_nodes = { #define _(s,n) [TCP_RESET_NEXT_##s] = n, foreach_tcp6_reset_next #undef _ }, .format_trace = format_tcp_tx_trace, }; /* *INDENT-ON* */ VLIB_NODE_FUNCTION_MULTIARCH (tcp6_reset_node, tcp6_send_reset); /* * fd.io coding-style-patch-verification: ON * * Local Variables: * eval: (c-set-style "gnu") * End: */