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authorFlorin Coras <fcoras@cisco.com>2017-04-26 00:08:42 -0700
committerFlorin Coras <fcoras@cisco.com>2017-05-01 10:41:44 -0700
commitc28764fd356632763614ea579f678d8f55eca4c7 (patch)
tree2c46999bc9474a5604f057812e6c25a821621b2c /src/vnet
parent63c7e14f2e62caa1246349cfe341a93176ec4a43 (diff)
TCP ooo reception fixes
- Improve svm fifo handling of out-of-order segments - Ensure tsval_recent is updated only if rcv_las falls withing the segments's sequence space - Avoid directly dropping old ACKs - Improve debugging Change-Id: I88dbe2394a0ad7eb389a4cc12d013a13733953aa Signed-off-by: Florin Coras <fcoras@cisco.com>
Diffstat (limited to 'src/vnet')
-rw-r--r--src/vnet/session/session.c15
-rw-r--r--src/vnet/session/session.h7
-rwxr-xr-xsrc/vnet/tcp/tcp_debug.h15
-rw-r--r--src/vnet/tcp/tcp_error.def3
-rw-r--r--src/vnet/tcp/tcp_format.c6
-rw-r--r--src/vnet/tcp/tcp_input.c81
-rw-r--r--src/vnet/tcp/tcp_output.c4
-rw-r--r--src/vnet/tcp/tcp_test.c114
8 files changed, 205 insertions, 40 deletions
diff --git a/src/vnet/session/session.c b/src/vnet/session/session.c
index d17c93f8f69..e92bb440601 100644
--- a/src/vnet/session/session.c
+++ b/src/vnet/session/session.c
@@ -609,6 +609,21 @@ session_manager_flush_enqueue_events (u32 thread_index)
return errors;
}
+/**
+ * Init fifo tail and head pointers
+ *
+ * Useful if transport uses absolute offsets for tracking ooo segments.
+ */
+void
+stream_session_init_fifos_pointers (transport_connection_t * tc,
+ u32 rx_pointer, u32 tx_pointer)
+{
+ stream_session_t *s;
+ s = stream_session_get (tc->s_index, tc->thread_index);
+ svm_fifo_init_pointers (s->server_rx_fifo, rx_pointer);
+ svm_fifo_init_pointers (s->server_tx_fifo, tx_pointer);
+}
+
void
stream_session_connect_notify (transport_connection_t * tc, u8 sst,
u8 is_fail)
diff --git a/src/vnet/session/session.h b/src/vnet/session/session.h
index 8cd72f3577a..f41a8a96eb5 100644
--- a/src/vnet/session/session.h
+++ b/src/vnet/session/session.h
@@ -352,9 +352,10 @@ stream_session_peek_bytes (transport_connection_t * tc, u8 * buffer,
u32 offset, u32 max_bytes);
u32 stream_session_dequeue_drop (transport_connection_t * tc, u32 max_bytes);
-void
-stream_session_connect_notify (transport_connection_t * tc, u8 sst,
- u8 is_fail);
+void stream_session_connect_notify (transport_connection_t * tc, u8 sst,
+ u8 is_fail);
+void stream_session_init_fifos_pointers (transport_connection_t * tc,
+ u32 rx_pointer, u32 tx_pointer);
void stream_session_accept_notify (transport_connection_t * tc);
void stream_session_disconnect_notify (transport_connection_t * tc);
diff --git a/src/vnet/tcp/tcp_debug.h b/src/vnet/tcp/tcp_debug.h
index ecbf78874fb..b4497a3b8d8 100755
--- a/src/vnet/tcp/tcp_debug.h
+++ b/src/vnet/tcp/tcp_debug.h
@@ -50,6 +50,7 @@
_(CC_EVT, "cc event") \
_(CC_PACK, "cc partial ack") \
_(SEG_INVALID, "invalid segment") \
+ _(PAWS_FAIL, "failed paws check") \
_(ACK_RCV_ERR, "invalid ack") \
_(RCV_WND_SHRUNK, "shrunk rcv_wnd") \
@@ -382,6 +383,20 @@ typedef enum _tcp_dbg_evt
ed->data[4] = _tc->rcv_wnd; \
}
+#define TCP_EVT_PAWS_FAIL_HANDLER(_tc, _seq, _end, ...) \
+{ \
+ ELOG_TYPE_DECLARE (_e) = \
+ { \
+ .format = "paws fail: seq %u end %u tsval %u tsval_recent %u", \
+ .format_args = "i4i4i4i4", \
+ }; \
+ DECLARE_ETD(_tc, _e, 4); \
+ ed->data[0] = _seq - _tc->irs; \
+ ed->data[1] = _end - _tc->irs; \
+ ed->data[2] = _tc->opt.tsval; \
+ ed->data[3] = _tc->tsval_recent; \
+}
+
#define TCP_EVT_ACK_RCV_ERR_HANDLER(_tc, _type, _ack, ...) \
{ \
ELOG_TYPE_DECLARE (_e) = \
diff --git a/src/vnet/tcp/tcp_error.def b/src/vnet/tcp/tcp_error.def
index 0d75d9751d7..a4e46d64629 100644
--- a/src/vnet/tcp/tcp_error.def
+++ b/src/vnet/tcp/tcp_error.def
@@ -37,4 +37,5 @@ tcp_error (PKTS_SENT, "Packets sent")
tcp_error (FILTERED_DUPACKS, "Filtered duplicate ACKs")
tcp_error (RST_SENT, "Resets sent")
tcp_error (INVALID_CONNECTION, "Invalid connection")
-tcp_error (NO_WND, "No window") \ No newline at end of file
+tcp_error (NO_WND, "No window")
+tcp_error (CONNECTION_CLOSED, "Connection closed") \ No newline at end of file
diff --git a/src/vnet/tcp/tcp_format.c b/src/vnet/tcp/tcp_format.c
index 3148fd406c9..4de99235934 100644
--- a/src/vnet/tcp/tcp_format.c
+++ b/src/vnet/tcp/tcp_format.c
@@ -131,11 +131,13 @@ format_tcp_header (u8 * s, va_list * args)
u8 *
format_tcp_sacks (u8 * s, va_list * args)
{
- sack_block_t *sacks = va_arg (*args, sack_block_t *);
+ tcp_connection_t *tc = va_arg (*args, tcp_connection_t *);
+ sack_block_t *sacks = tc->snd_sacks;
sack_block_t *block;
vec_foreach (block, sacks)
{
- s = format (s, " start %u end %u\n", block->start, block->end);
+ s = format (s, " start %u end %u\n", block->start - tc->irs,
+ block->end - tc->irs);
}
return s;
}
diff --git a/src/vnet/tcp/tcp_input.c b/src/vnet/tcp/tcp_input.c
index 3c65a5ea73d..0030cfe24ab 100644
--- a/src/vnet/tcp/tcp_input.c
+++ b/src/vnet/tcp/tcp_input.c
@@ -208,6 +208,15 @@ tcp_options_parse (tcp_header_t * th, tcp_options_t * to)
}
}
+/**
+ * RFC1323: Check against wrapped sequence numbers (PAWS). If we have
+ * timestamp to echo and it's less than tsval_recent, drop segment
+ * but still send an ACK in order to retain TCP's mechanism for detecting
+ * and recovering from half-open connections
+ *
+ * Or at least that's what the theory says. It seems that this might not work
+ * very well with packet reordering and fast retransmit. XXX
+ */
always_inline int
tcp_segment_check_paws (tcp_connection_t * tc)
{
@@ -216,6 +225,27 @@ tcp_segment_check_paws (tcp_connection_t * tc)
}
/**
+ * Update tsval recent
+ */
+always_inline void
+tcp_update_timestamp (tcp_connection_t * tc, u32 seq, u32 seq_end)
+{
+ /*
+ * RFC1323: If Last.ACK.sent falls within the range of sequence numbers
+ * of an incoming segment:
+ * SEG.SEQ <= Last.ACK.sent < SEG.SEQ + SEG.LEN
+ * then the TSval from the segment is copied to TS.Recent;
+ * otherwise, the TSval is ignored.
+ */
+ if (tcp_opts_tstamp (&tc->opt) && tc->tsval_recent
+ && seq_leq (seq, tc->rcv_las) && seq_leq (tc->rcv_las, seq_end))
+ {
+ tc->tsval_recent = tc->opt.tsval;
+ tc->tsval_recent_age = tcp_time_now ();
+ }
+}
+
+/**
* Validate incoming segment as per RFC793 p. 69 and RFC1323 p. 19
*
* It first verifies if segment has a wrapped sequence number (PAWS) and then
@@ -228,21 +258,16 @@ static int
tcp_segment_validate (vlib_main_t * vm, tcp_connection_t * tc0,
vlib_buffer_t * b0, tcp_header_t * th0, u32 * next0)
{
- u8 paws_failed;
-
if (PREDICT_FALSE (!tcp_ack (th0) && !tcp_rst (th0) && !tcp_syn (th0)))
return -1;
tcp_options_parse (th0, &tc0->opt);
- /* RFC1323: Check against wrapped sequence numbers (PAWS). If we have
- * timestamp to echo and it's less than tsval_recent, drop segment
- * but still send an ACK in order to retain TCP's mechanism for detecting
- * and recovering from half-open connections */
- paws_failed = tcp_segment_check_paws (tc0);
- if (paws_failed)
+ if (tcp_segment_check_paws (tc0))
{
clib_warning ("paws failed");
+ TCP_EVT_DBG (TCP_EVT_PAWS_FAIL, tc0, vnet_buffer (b0)->tcp.seq_number,
+ vnet_buffer (b0)->tcp.seq_end);
/* If it just so happens that a segment updates tsval_recent for a
* segment over 24 days old, invalidate tsval_recent. */
@@ -251,6 +276,7 @@ tcp_segment_validate (vlib_main_t * vm, tcp_connection_t * tc0,
{
/* Age isn't reset until we get a valid tsval (bsd inspired) */
tc0->tsval_recent = 0;
+ clib_warning ("paws failed - really old segment. REALLY?");
}
else
{
@@ -305,12 +331,9 @@ tcp_segment_validate (vlib_main_t * vm, tcp_connection_t * tc0,
return -1;
}
- /* If PAWS passed and segment in window, save timestamp */
- if (!paws_failed)
- {
- tc0->tsval_recent = tc0->opt.tsval;
- tc0->tsval_recent_age = tcp_time_now ();
- }
+ /* If segment in window, save timestamp */
+ tcp_update_timestamp (tc0, vnet_buffer (b0)->tcp.seq_number,
+ vnet_buffer (b0)->tcp.seq_end);
return 0;
}
@@ -835,7 +858,8 @@ tcp_rcv_ack (tcp_connection_t * tc, vlib_buffer_t * b,
TCP_EVT_DBG (TCP_EVT_DUPACK_RCVD, tc);
tcp_cc_rcv_dupack (tc, vnet_buffer (b)->tcp.ack_number);
}
- return -1;
+ /* Don't drop yet */
+ return 0;
}
if (tcp_opts_sack_permitted (&tc->opt))
@@ -932,10 +956,6 @@ tcp_update_sack_list (tcp_connection_t * tc, u32 start, u32 end)
{
vec_add1 (new_list, tc->snd_sacks[i]);
}
- else
- {
- clib_warning ("dropped sack blocks");
- }
}
ASSERT (vec_len (new_list) <= TCP_MAX_SACK_BLOCKS);
@@ -1011,7 +1031,6 @@ tcp_session_enqueue_ooo (tcp_connection_t * tc, vlib_buffer_t * b,
u16 data_len)
{
stream_session_t *s0;
- u32 offset;
int rv;
/* Pure ACK. Do nothing */
@@ -1021,12 +1040,11 @@ tcp_session_enqueue_ooo (tcp_connection_t * tc, vlib_buffer_t * b,
}
s0 = stream_session_get (tc->c_s_index, tc->c_thread_index);
- offset = vnet_buffer (b)->tcp.seq_number - tc->irs;
- clib_warning ("ooo: offset %d len %d", offset, data_len);
-
- rv = svm_fifo_enqueue_with_offset (s0->server_rx_fifo, offset, data_len,
- vlib_buffer_get_current (b));
+ /* Enqueue out-of-order data with absolute offset */
+ rv = svm_fifo_enqueue_with_offset (s0->server_rx_fifo,
+ vnet_buffer (b)->tcp.seq_number,
+ data_len, vlib_buffer_get_current (b));
/* Nothing written */
if (rv)
@@ -1542,6 +1560,9 @@ tcp46_syn_sent_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
/* Notify app that we have connection */
stream_session_connect_notify (&new_tc0->connection, sst, 0);
+ stream_session_init_fifos_pointers (&new_tc0->connection,
+ new_tc0->irs + 1,
+ new_tc0->iss + 1);
/* Make sure after data segment processing ACK is sent */
new_tc0->flags |= TCP_CONN_SNDACK;
}
@@ -1552,7 +1573,9 @@ tcp46_syn_sent_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
/* Notify app that we have connection */
stream_session_connect_notify (&new_tc0->connection, sst, 0);
-
+ stream_session_init_fifos_pointers (&new_tc0->connection,
+ new_tc0->irs + 1,
+ new_tc0->iss + 1);
tcp_make_synack (new_tc0, b0);
next0 = tcp_next_output (is_ip4);
@@ -2139,6 +2162,10 @@ tcp46_listen_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
tcp_make_synack (child0, b0);
next0 = tcp_next_output (is_ip4);
+ /* Init fifo pointers after we have iss */
+ stream_session_init_fifos_pointers (&child0->connection,
+ child0->irs + 1,
+ child0->iss + 1);
drop:
if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
{
@@ -2474,6 +2501,7 @@ do { \
_(LISTEN, TCP_FLAG_SYN, TCP_INPUT_NEXT_LISTEN, TCP_ERROR_NONE);
/* ACK for for a SYN-ACK -> tcp-rcv-process. */
_(SYN_RCVD, TCP_FLAG_ACK, TCP_INPUT_NEXT_RCV_PROCESS, TCP_ERROR_NONE);
+ _(SYN_RCVD, TCP_FLAG_RST, TCP_INPUT_NEXT_RCV_PROCESS, TCP_ERROR_NONE);
/* SYN-ACK for a SYN */
_(SYN_SENT, TCP_FLAG_SYN | TCP_FLAG_ACK, TCP_INPUT_NEXT_SYN_SENT,
TCP_ERROR_NONE);
@@ -2499,6 +2527,7 @@ do { \
_(FIN_WAIT_2, TCP_FLAG_FIN | TCP_FLAG_ACK, TCP_INPUT_NEXT_RCV_PROCESS,
TCP_ERROR_NONE);
_(LAST_ACK, TCP_FLAG_ACK, TCP_INPUT_NEXT_RCV_PROCESS, TCP_ERROR_NONE);
+ _(CLOSED, TCP_FLAG_ACK, TCP_INPUT_NEXT_DROP, TCP_ERROR_CONNECTION_CLOSED);
#undef _
}
diff --git a/src/vnet/tcp/tcp_output.c b/src/vnet/tcp/tcp_output.c
index 4e1a7aa5ef4..a85d30daddb 100644
--- a/src/vnet/tcp/tcp_output.c
+++ b/src/vnet/tcp/tcp_output.c
@@ -359,7 +359,8 @@ tcp_make_established_options (tcp_connection_t * tc, tcp_options_t * opts)
{
opts->flags |= TCP_OPTS_FLAG_SACK;
opts->sacks = tc->snd_sacks;
- opts->n_sack_blocks = vec_len (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;
}
}
@@ -917,6 +918,7 @@ tcp_push_hdr_i (tcp_connection_t * tc, vlib_buffer_t * b,
vnet_buffer (b)->tcp.connection_index = tc->c_c_index;
tc->snd_nxt += data_len;
+ tc->rcv_las = tc->rcv_nxt;
/* TODO this is updated in output as well ... */
if (tc->snd_nxt > tc->snd_una_max)
diff --git a/src/vnet/tcp/tcp_test.c b/src/vnet/tcp/tcp_test.c
index ed0322062bd..a457ac8f7fa 100644
--- a/src/vnet/tcp/tcp_test.c
+++ b/src/vnet/tcp/tcp_test.c
@@ -231,7 +231,7 @@ tcp_test_sack_tx (vlib_main_t * vm, unformat_input_t * input)
tcp_update_sack_list (tc, 300, 300);
if (verbose)
vlib_cli_output (vm, "overlap first 2 segments:\n%U",
- format_tcp_sacks, tc->snd_sacks);
+ format_tcp_sacks, tc);
TCP_TEST ((vec_len (tc->snd_sacks) == 3), "sack blocks %d expected %d",
vec_len (tc->snd_sacks), 3);
TCP_TEST ((tc->snd_sacks[0].start == 900),
@@ -244,7 +244,7 @@ tcp_test_sack_tx (vlib_main_t * vm, unformat_input_t * input)
tcp_update_sack_list (tc, 1100, 1200);
if (verbose)
vlib_cli_output (vm, "add new segment [1100, 1200]\n%U",
- format_tcp_sacks, tc->snd_sacks);
+ format_tcp_sacks, tc);
TCP_TEST ((vec_len (tc->snd_sacks) == 4), "sack blocks %d expected %d",
vec_len (tc->snd_sacks), 4);
TCP_TEST ((tc->snd_sacks[0].start == 1100),
@@ -257,7 +257,7 @@ tcp_test_sack_tx (vlib_main_t * vm, unformat_input_t * input)
tcp_update_sack_list (tc, 800, 900);
if (verbose)
vlib_cli_output (vm, "join middle segments [800, 900]\n%U",
- format_tcp_sacks, tc->snd_sacks);
+ format_tcp_sacks, tc);
TCP_TEST ((vec_len (tc->snd_sacks) == 3), "sack blocks %d expected %d",
vec_len (tc->snd_sacks), 3);
@@ -271,8 +271,7 @@ tcp_test_sack_tx (vlib_main_t * vm, unformat_input_t * input)
tc->rcv_nxt = 1200;
tcp_update_sack_list (tc, 1200, 1200);
if (verbose)
- vlib_cli_output (vm, "advance rcv_nxt to 1200\n%U",
- format_tcp_sacks, tc->snd_sacks);
+ vlib_cli_output (vm, "advance rcv_nxt to 1200\n%U", format_tcp_sacks, tc);
TCP_TEST ((vec_len (tc->snd_sacks) == 0), "sack blocks %d expected %d",
vec_len (tc->snd_sacks), 0);
return 0;
@@ -502,7 +501,13 @@ tcp_test_fifo1 (vlib_main_t * vm, unformat_input_t * input)
{
offset = (2 * i + 1) * sizeof (u32);
data = (u8 *) (test_data + (2 * i + 1));
- rv = svm_fifo_enqueue_with_offset (f, offset, sizeof (u32), data);
+ if (i == 0)
+ {
+ rv = svm_fifo_enqueue_nowait (f, sizeof (u32), data);
+ rv = rv > 0 ? 0 : rv;
+ }
+ else
+ rv = svm_fifo_enqueue_with_offset (f, offset, sizeof (u32), data);
if (verbose)
vlib_cli_output (vm, "add [%d] [%d, %d]", 2 * i + 1, offset,
offset + sizeof (u32));
@@ -517,6 +522,26 @@ tcp_test_fifo1 (vlib_main_t * vm, unformat_input_t * input)
vlib_cli_output (vm, "fifo after odd segs: %U", format_svm_fifo, f, 1);
TCP_TEST ((f->tail == 8), "fifo tail %u", f->tail);
+ TCP_TEST ((svm_fifo_number_ooo_segments (f) == 2),
+ "number of ooo segments %u", svm_fifo_number_ooo_segments (f));
+
+ /*
+ * Try adding a completely overlapped segment
+ */
+ offset = 3 * sizeof (u32);
+ data = (u8 *) (test_data + 3);
+ rv = svm_fifo_enqueue_with_offset (f, offset, sizeof (u32), data);
+ if (rv)
+ {
+ clib_warning ("enqueue returned %d", rv);
+ goto err;
+ }
+
+ if (verbose)
+ vlib_cli_output (vm, "fifo after overlap seg: %U", format_svm_fifo, f, 1);
+
+ TCP_TEST ((svm_fifo_number_ooo_segments (f) == 2),
+ "number of ooo segments %u", svm_fifo_number_ooo_segments (f));
/*
* Make sure format functions are not buggy
@@ -887,7 +912,7 @@ tcp_test_fifo3 (vlib_main_t * vm, unformat_input_t * input)
f->head = fifo_initial_offset;
f->tail = fifo_initial_offset;
- for (i = 0; i < vec_len (generate); i++)
+ for (i = !randomize; i < vec_len (generate); i++)
{
tp = generate + i;
svm_fifo_enqueue_with_offset (f, fifo_initial_offset + tp->offset,
@@ -895,6 +920,10 @@ tcp_test_fifo3 (vlib_main_t * vm, unformat_input_t * input)
(u8 *) data_pattern + tp->offset);
}
+ /* Add the first segment in order for non random data */
+ if (!randomize)
+ svm_fifo_enqueue_nowait (f, generate[0].len, (u8 *) data_pattern);
+
/*
* Expected result: one big fat chunk at offset 1 if randomize == 1
*/
@@ -965,6 +994,73 @@ tcp_test_fifo3 (vlib_main_t * vm, unformat_input_t * input)
}
static int
+tcp_test_fifo4 (vlib_main_t * vm, unformat_input_t * input)
+{
+ svm_fifo_t *f;
+ u32 fifo_size = 6 << 10;
+ u32 fifo_initial_offset = 1000000000;
+ u32 test_n_bytes = 5000, j;
+ u8 *test_data = 0, *data_buf = 0;
+ int i, rv, verbose = 0;
+
+ while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
+ {
+ if (unformat (input, "verbose"))
+ verbose = 1;
+ else
+ {
+ clib_error_t *e = clib_error_return
+ (0, "unknown input `%U'", format_unformat_error, input);
+ clib_error_report (e);
+ return -1;
+ }
+ }
+
+ /*
+ * Create a fifo and add segments
+ */
+ f = fifo_prepare (fifo_size);
+
+ /* Set head and tail pointers */
+ fifo_initial_offset = fifo_initial_offset % fifo_size;
+ svm_fifo_init_pointers (f, fifo_initial_offset);
+
+ vec_validate (test_data, test_n_bytes - 1);
+ for (i = 0; i < vec_len (test_data); i++)
+ test_data[i] = i;
+
+ for (i = test_n_bytes - 1; i > 0; i--)
+ {
+ rv = svm_fifo_enqueue_with_offset (f, fifo_initial_offset + i,
+ sizeof (u8), &test_data[i]);
+ if (verbose)
+ vlib_cli_output (vm, "add [%d] [%d, %d]", i, i, i + sizeof (u8));
+ if (rv)
+ {
+ clib_warning ("enqueue returned %d", rv);
+ svm_fifo_free (f);
+ vec_free (test_data);
+ return -1;
+ }
+ }
+
+ svm_fifo_enqueue_nowait (f, sizeof (u8), &test_data[0]);
+
+ vec_validate (data_buf, vec_len (test_data));
+
+ svm_fifo_dequeue_nowait (f, vec_len (test_data), data_buf);
+ rv = compare_data (data_buf, test_data, 0, vec_len (test_data), &j);
+ if (rv)
+ vlib_cli_output (vm, "[%d] dequeued %u expected %u", j, data_buf[j],
+ test_data[j]);
+ TCP_TEST ((rv == 0), "dequeued compared to original returned %d", rv);
+
+ svm_fifo_free (f);
+ vec_free (test_data);
+ return 0;
+}
+
+static int
tcp_test_fifo (vlib_main_t * vm, unformat_input_t * input)
{
int res = 0;
@@ -1028,6 +1124,10 @@ tcp_test_fifo (vlib_main_t * vm, unformat_input_t * input)
{
res = tcp_test_fifo1 (vm, input);
}
+ else if (unformat (input, "fifo4"))
+ {
+ res = tcp_test_fifo4 (vm, input);
+ }
}
return res;