blob: 9cb3e77937ebc7e5dc1f999f1cfaab2542e6a94a [file] [log] [blame]
/*
* 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 *);
uword 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)
{
u32 current_length = vec_len (tm->tx_buffers[thread_index]);
vec_validate (tm->tx_buffers[thread_index],
current_length + n_free_buffers - 1);
_vec_len (tm->tx_buffers[thread_index]) = current_length
+ vlib_buffer_alloc (vlib_get_main (),
&tm->tx_buffers[thread_index][current_length],
n_free_buffers);
/* 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 ();
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;
/* 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);
tcp_timer_update (tc, TCP_TIMER_RETRANSMIT_SYN,
tc->rto * TCP_TO_TIMER_TICK);
}
/**
* 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 (vlib_main_t * vm, vlib_buffer_t * b, u32 bi,
u8 is_ip4)
{
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;
f = vlib_get_frame_to_node (vm, next_index);
/* Enqueue the packet */
to_next = vlib_frame_vector_args (f);
to_next[0] = bi;
f->n_vectors = 1;
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)
{
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);
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 (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;
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)
{
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 ();
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;
/* Set the connection establishment timer */
tcp_timer_set (tc, TCP_TIMER_ESTABLISH, TCP_ESTABLISH_TIME);
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 both v4 and v6 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);
}
/**
* Send FIN
*/
void
tcp_send_fin (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 ();
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);
if (!(tc->flags & TCP_CONN_FINSNT))
{
tc->flags |= TCP_CONN_FINSNT;
tc->flags &= ~TCP_CONN_FINPNDG;
tc->snd_nxt += 1;
}
tcp_retransmit_timer_force_update (tc);
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;
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);
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;
tc->snd_nxt = tc->snd_una;
/* First retransmit timeout */
if (tc->rto_boff == 1)
tcp_rtx_timeout_cc (tc);
/* Exponential backoff */
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)
{
ASSERT (!b);
if (tc->snd_una == tc->snd_una_max)
return;
ASSERT (tc->rto_boff > 1 && tc->snd_una == tc->snd_congestion);
clib_warning ("retransmit fail: %U", format_tcp_connection, tc, 2);
/* Try again eventually */
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);
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;
tc->rto = clib_min (tc->rto << 1, TCP_RTO_MAX);
tc->rtt_ts = 0;
if (PREDICT_FALSE (tcp_get_free_buffer_index (tm, &bi)))
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);
clib_warning ("connection 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, old_snd_nxt, 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 && (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;
tcp_push_hdr_i (tc, b, tc->state, 0);
tc->snd_nxt = old_snd_nxt;
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 =
stream_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;
}
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:
*/