FD.io VPP  v17.07-30-g839fa73
Vector Packet Processing
tcp_input.c File Reference
+ Include dependency graph for tcp_input.c:

Go to the source code of this file.

Data Structures

struct  tcp_rx_trace_t
 

Macros

#define tcp_error(n, s)   s,
 
#define foreach_tcp_state_next
 
#define tcp_next_output(is_ip4)
 
#define foreach_tcp4_input_next
 
#define foreach_tcp6_input_next
 
#define filter_flags   (TCP_FLAG_SYN|TCP_FLAG_ACK|TCP_FLAG_RST|TCP_FLAG_FIN)
 

Typedefs

typedef enum _tcp_established_next tcp_established_next_t
 
typedef enum _tcp_rcv_process_next tcp_rcv_process_next_t
 
typedef enum _tcp_syn_sent_next tcp_syn_sent_next_t
 
typedef enum _tcp_listen_next tcp_listen_next_t
 
typedef enum _tcp_state_next tcp_state_next_t
 
typedef enum _tcp_input_next tcp_input_next_t
 

Functions

static u8 tcp_segment_in_rcv_wnd (tcp_connection_t *tc, u32 seq, u32 end_seq)
 Validate segment sequence number. More...
 
int tcp_options_parse (tcp_header_t *th, tcp_options_t *to)
 Parse TCP header options. More...
 
static int tcp_segment_check_paws (tcp_connection_t *tc)
 RFC1323: Check against wrapped sequence numbers (PAWS). More...
 
static void tcp_update_timestamp (tcp_connection_t *tc, u32 seq, u32 seq_end)
 Update tsval recent. More...
 
static int tcp_segment_validate (vlib_main_t *vm, tcp_connection_t *tc0, vlib_buffer_t *b0, tcp_header_t *th0, u32 *next0)
 Validate incoming segment as per RFC793 p. More...
 
static int tcp_rcv_ack_is_acceptable (tcp_connection_t *tc0, vlib_buffer_t *tb0)
 
static void tcp_estimate_rtt (tcp_connection_t *tc, u32 mrtt)
 Compute smoothed RTT as per VJ's '88 SIGCOMM and RFC6298. More...
 
void tcp_update_rto (tcp_connection_t *tc)
 
static int tcp_update_rtt (tcp_connection_t *tc, u32 ack)
 Update RTT estimate and RTO timer. More...
 
static void tcp_dequeue_acked (tcp_connection_t *tc, u32 ack)
 Dequeue bytes that have been acked and while at it update RTT estimates. More...
 
static u8 tcp_ack_is_dupack (tcp_connection_t *tc, vlib_buffer_t *b, u32 prev_snd_wnd, u32 prev_snd_una)
 Check if duplicate ack as per RFC5681 Sec. More...
 
static u8 tcp_ack_is_cc_event (tcp_connection_t *tc, vlib_buffer_t *b, u32 prev_snd_wnd, u32 prev_snd_una, u8 *is_dack)
 Checks if ack is a congestion control event. More...
 
void scoreboard_remove_hole (sack_scoreboard_t *sb, sack_scoreboard_hole_t *hole)
 
sack_scoreboard_hole_tscoreboard_insert_hole (sack_scoreboard_t *sb, u32 prev_index, u32 start, u32 end)
 
void scoreboard_update_bytes (tcp_connection_t *tc, sack_scoreboard_t *sb)
 
sack_scoreboard_hole_tscoreboard_next_rxt_hole (sack_scoreboard_t *sb, sack_scoreboard_hole_t *start, u8 have_sent_1_smss, u8 *can_rescue, u8 *snd_limited)
 Figure out the next hole to retransmit. More...
 
void scoreboard_init_high_rxt (sack_scoreboard_t *sb)
 
void tcp_rcv_sacks (tcp_connection_t *tc, u32 ack)
 
static void tcp_update_snd_wnd (tcp_connection_t *tc, u32 seq, u32 ack, u32 snd_wnd)
 Try to update snd_wnd based on feedback received from peer. More...
 
void tcp_cc_init_congestion (tcp_connection_t *tc)
 
static void tcp_cc_recovery_exit (tcp_connection_t *tc)
 
void tcp_cc_fastrecovery_exit (tcp_connection_t *tc)
 
static void tcp_cc_congestion_undo (tcp_connection_t *tc)
 
static u8 tcp_cc_is_spurious_retransmit (tcp_connection_t *tc)
 
int tcp_cc_recover (tcp_connection_t *tc)
 
static void tcp_cc_update (tcp_connection_t *tc, vlib_buffer_t *b)
 
static u8 tcp_should_fastrecover_sack (tcp_connection_t *tc)
 
static u8 tcp_should_fastrecover (tcp_connection_t *tc)
 
static void tcp_cc_handle_event (tcp_connection_t *tc, u32 is_dack)
 One function to rule them all ... More...
 
void tcp_cc_init (tcp_connection_t *tc)
 
static int tcp_rcv_ack (tcp_connection_t *tc, vlib_buffer_t *b, tcp_header_t *th, u32 *next, u32 *error)
 Process incoming ACK. More...
 
void tcp_update_sack_list (tcp_connection_t *tc, u32 start, u32 end)
 Build SACK list as per RFC2018. More...
 
static int tcp_session_enqueue_data (tcp_connection_t *tc, vlib_buffer_t *b, u16 data_len)
 Enqueue data for delivery to application. More...
 
static int tcp_session_enqueue_ooo (tcp_connection_t *tc, vlib_buffer_t *b, u16 data_len)
 Enqueue out-of-order data. More...
 
static int tcp_can_delack (tcp_connection_t *tc)
 Check if ACK could be delayed. More...
 
static int tcp_segment_rcv (tcp_main_t *tm, tcp_connection_t *tc, vlib_buffer_t *b, u16 n_data_bytes, u32 *next0)
 
u8format_tcp_rx_trace (u8 *s, va_list *args)
 
u8format_tcp_rx_trace_short (u8 *s, va_list *args)
 
void tcp_set_rx_trace_data (tcp_rx_trace_t *t0, tcp_connection_t *tc0, tcp_header_t *th0, vlib_buffer_t *b0, u8 is_ip4)
 
static void tcp_established_inc_counter (vlib_main_t *vm, u8 is_ip4, u8 evt, u8 val)
 
static uword tcp46_established_inline (vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *from_frame, int is_ip4)
 
static uword tcp4_established (vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *from_frame)
 
static uword tcp6_established (vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *from_frame)
 
 VLIB_NODE_FUNCTION_MULTIARCH (tcp4_established_node, tcp4_established)
 
 VLIB_NODE_FUNCTION_MULTIARCH (tcp6_established_node, tcp6_established)
 
static uword tcp46_syn_sent_inline (vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *from_frame, int is_ip4)
 
static uword tcp4_syn_sent (vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *from_frame)
 
static uword tcp6_syn_sent_rcv (vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *from_frame)
 
 VLIB_NODE_FUNCTION_MULTIARCH (tcp4_syn_sent_node, tcp4_syn_sent)
 
 VLIB_NODE_FUNCTION_MULTIARCH (tcp6_syn_sent_node, tcp6_syn_sent_rcv)
 
static uword tcp46_rcv_process_inline (vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *from_frame, int is_ip4)
 Handles reception for all states except LISTEN, SYN-SENT and ESTABLISHED as per RFC793 p. More...
 
static uword tcp4_rcv_process (vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *from_frame)
 
static uword tcp6_rcv_process (vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *from_frame)
 
 VLIB_NODE_FUNCTION_MULTIARCH (tcp4_rcv_process_node, tcp4_rcv_process)
 
 VLIB_NODE_FUNCTION_MULTIARCH (tcp6_rcv_process_node, tcp6_rcv_process)
 
static uword tcp46_listen_inline (vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *from_frame, int is_ip4)
 LISTEN state processing as per RFC 793 p. More...
 
static uword tcp4_listen (vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *from_frame)
 
static uword tcp6_listen (vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *from_frame)
 
 VLIB_NODE_FUNCTION_MULTIARCH (tcp4_listen_node, tcp4_listen)
 
 VLIB_NODE_FUNCTION_MULTIARCH (tcp6_listen_node, tcp6_listen)
 
static uword tcp46_input_inline (vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *from_frame, int is_ip4)
 
static uword tcp4_input (vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *from_frame)
 
static uword tcp6_input (vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *from_frame)
 
 VLIB_NODE_FUNCTION_MULTIARCH (tcp4_input_node, tcp4_input)
 
 VLIB_NODE_FUNCTION_MULTIARCH (tcp6_input_node, tcp6_input)
 
static void tcp_dispatch_table_init (tcp_main_t *tm)
 
clib_error_ttcp_input_init (vlib_main_t *vm)
 

Variables

static char * tcp_error_strings []
 
vlib_node_registration_t tcp4_established_node
 (constructor) VLIB_REGISTER_NODE (tcp4_established_node) More...
 
vlib_node_registration_t tcp6_established_node
 (constructor) VLIB_REGISTER_NODE (tcp6_established_node) More...
 
vlib_node_registration_t tcp4_syn_sent_node
 (constructor) VLIB_REGISTER_NODE (tcp4_syn_sent_node) More...
 
vlib_node_registration_t tcp6_syn_sent_node
 (constructor) VLIB_REGISTER_NODE (tcp6_syn_sent_node) More...
 
vlib_node_registration_t tcp4_rcv_process_node
 (constructor) VLIB_REGISTER_NODE (tcp4_rcv_process_node) More...
 
vlib_node_registration_t tcp6_rcv_process_node
 (constructor) VLIB_REGISTER_NODE (tcp6_rcv_process_node) More...
 
vlib_node_registration_t tcp4_listen_node
 (constructor) VLIB_REGISTER_NODE (tcp4_listen_node) More...
 
vlib_node_registration_t tcp6_listen_node
 (constructor) VLIB_REGISTER_NODE (tcp6_listen_node) More...
 
vlib_node_registration_t tcp4_input_node
 (constructor) VLIB_REGISTER_NODE (tcp4_input_node) More...
 
vlib_node_registration_t tcp6_input_node
 (constructor) VLIB_REGISTER_NODE (tcp6_input_node) More...
 

Macro Definition Documentation

#define filter_flags   (TCP_FLAG_SYN|TCP_FLAG_ACK|TCP_FLAG_RST|TCP_FLAG_FIN)

Definition at line 2660 of file tcp_input.c.

#define foreach_tcp4_input_next
Value:
_ (DROP, "error-drop") \
_ (LISTEN, "tcp4-listen") \
_ (RCV_PROCESS, "tcp4-rcv-process") \
_ (SYN_SENT, "tcp4-syn-sent") \
_ (ESTABLISHED, "tcp4-established") \
_ (RESET, "tcp4-reset")
DROP
Definition: error.def:41

Definition at line 2644 of file tcp_input.c.

#define foreach_tcp6_input_next
Value:
_ (DROP, "error-drop") \
_ (LISTEN, "tcp6-listen") \
_ (RCV_PROCESS, "tcp6-rcv-process") \
_ (SYN_SENT, "tcp6-syn-sent") \
_ (ESTABLISHED, "tcp6-established") \
_ (RESET, "tcp6-reset")
DROP
Definition: error.def:41

Definition at line 2652 of file tcp_input.c.

#define foreach_tcp_state_next
Value:
_ (DROP, "error-drop") \
_ (TCP4_OUTPUT, "tcp4-output") \
_ (TCP6_OUTPUT, "tcp6-output")
DROP
Definition: error.def:41

Definition at line 29 of file tcp_input.c.

#define tcp_error (   n,
 
)    s,
#define tcp_next_output (   is_ip4)
Value:
(is_ip4 ? TCP_NEXT_TCP4_OUTPUT \
: TCP_NEXT_TCP6_OUTPUT)

Definition at line 75 of file tcp_input.c.

Typedef Documentation

typedef enum _tcp_established_next tcp_established_next_t
typedef enum _tcp_input_next tcp_input_next_t
typedef enum _tcp_listen_next tcp_listen_next_t
typedef enum _tcp_rcv_process_next tcp_rcv_process_next_t
typedef enum _tcp_state_next tcp_state_next_t
typedef enum _tcp_syn_sent_next tcp_syn_sent_next_t

Function Documentation

u8* format_tcp_rx_trace ( u8 s,
va_list *  args 
)

Definition at line 1513 of file tcp_input.c.

+ Here is the call graph for this function:

u8* format_tcp_rx_trace_short ( u8 s,
va_list *  args 
)

Definition at line 1529 of file tcp_input.c.

+ Here is the call graph for this function:

+ Here is the caller graph for this function:

void scoreboard_init_high_rxt ( sack_scoreboard_t sb)

Definition at line 677 of file tcp_input.c.

+ Here is the call graph for this function:

+ Here is the caller graph for this function:

sack_scoreboard_hole_t* scoreboard_insert_hole ( sack_scoreboard_t sb,
u32  prev_index,
u32  start,
u32  end 
)

Definition at line 541 of file tcp_input.c.

+ Here is the call graph for this function:

+ Here is the caller graph for this function:

sack_scoreboard_hole_t* scoreboard_next_rxt_hole ( sack_scoreboard_t sb,
sack_scoreboard_hole_t start,
u8  have_sent_1_smss,
u8 can_rescue,
u8 snd_limited 
)

Figure out the next hole to retransmit.

Follows logic proposed in RFC6675 Sec. 4, NextSeg()

Definition at line 622 of file tcp_input.c.

+ Here is the call graph for this function:

+ Here is the caller graph for this function:

void scoreboard_remove_hole ( sack_scoreboard_t sb,
sack_scoreboard_hole_t hole 
)

Definition at line 510 of file tcp_input.c.

+ Here is the call graph for this function:

+ Here is the caller graph for this function:

void scoreboard_update_bytes ( tcp_connection_t tc,
sack_scoreboard_t sb 
)

Definition at line 578 of file tcp_input.c.

+ Here is the call graph for this function:

+ Here is the caller graph for this function:

static uword tcp46_established_inline ( vlib_main_t vm,
vlib_node_runtime_t node,
vlib_frame_t from_frame,
int  is_ip4 
)
inlinestatic

Definition at line 1571 of file tcp_input.c.

+ Here is the call graph for this function:

+ Here is the caller graph for this function:

static uword tcp46_input_inline ( vlib_main_t vm,
vlib_node_runtime_t node,
vlib_frame_t from_frame,
int  is_ip4 
)
inlinestatic

Definition at line 2663 of file tcp_input.c.

+ Here is the call graph for this function:

+ Here is the caller graph for this function:

static uword tcp46_listen_inline ( vlib_main_t vm,
vlib_node_runtime_t node,
vlib_frame_t from_frame,
int  is_ip4 
)
inlinestatic

LISTEN state processing as per RFC 793 p.

65

Definition at line 2417 of file tcp_input.c.

+ Here is the call graph for this function:

+ Here is the caller graph for this function:

static uword tcp46_rcv_process_inline ( vlib_main_t vm,
vlib_node_runtime_t node,
vlib_frame_t from_frame,
int  is_ip4 
)
inlinestatic

Handles reception for all states except LISTEN, SYN-SENT and ESTABLISHED as per RFC793 p.

64

Definition at line 2054 of file tcp_input.c.

+ Here is the call graph for this function:

+ Here is the caller graph for this function:

static uword tcp46_syn_sent_inline ( vlib_main_t vm,
vlib_node_runtime_t node,
vlib_frame_t from_frame,
int  is_ip4 
)
inlinestatic

Definition at line 1746 of file tcp_input.c.

+ Here is the call graph for this function:

+ Here is the caller graph for this function:

static uword tcp4_established ( vlib_main_t vm,
vlib_node_runtime_t node,
vlib_frame_t from_frame 
)
static

Definition at line 1684 of file tcp_input.c.

+ Here is the call graph for this function:

+ Here is the caller graph for this function:

static uword tcp4_input ( vlib_main_t vm,
vlib_node_runtime_t node,
vlib_frame_t from_frame 
)
static

Definition at line 2809 of file tcp_input.c.

+ Here is the call graph for this function:

static uword tcp4_listen ( vlib_main_t vm,
vlib_node_runtime_t node,
vlib_frame_t from_frame 
)
static

Definition at line 2573 of file tcp_input.c.

+ Here is the call graph for this function:

+ Here is the caller graph for this function:

static uword tcp4_rcv_process ( vlib_main_t vm,
vlib_node_runtime_t node,
vlib_frame_t from_frame 
)
static

Definition at line 2353 of file tcp_input.c.

+ Here is the call graph for this function:

static uword tcp4_syn_sent ( vlib_main_t vm,
vlib_node_runtime_t node,
vlib_frame_t from_frame 
)
static

Definition at line 1993 of file tcp_input.c.

+ Here is the call graph for this function:

+ Here is the caller graph for this function:

static uword tcp6_established ( vlib_main_t vm,
vlib_node_runtime_t node,
vlib_frame_t from_frame 
)
static

Definition at line 1691 of file tcp_input.c.

+ Here is the call graph for this function:

static uword tcp6_input ( vlib_main_t vm,
vlib_node_runtime_t node,
vlib_frame_t from_frame 
)
static

Definition at line 2816 of file tcp_input.c.

+ Here is the call graph for this function:

static uword tcp6_listen ( vlib_main_t vm,
vlib_node_runtime_t node,
vlib_frame_t from_frame 
)
static

Definition at line 2580 of file tcp_input.c.

+ Here is the call graph for this function:

static uword tcp6_rcv_process ( vlib_main_t vm,
vlib_node_runtime_t node,
vlib_frame_t from_frame 
)
static

Definition at line 2360 of file tcp_input.c.

+ Here is the call graph for this function:

static uword tcp6_syn_sent_rcv ( vlib_main_t vm,
vlib_node_runtime_t node,
vlib_frame_t from_frame 
)
static

Definition at line 2000 of file tcp_input.c.

+ Here is the call graph for this function:

static u8 tcp_ack_is_cc_event ( tcp_connection_t tc,
vlib_buffer_t b,
u32  prev_snd_wnd,
u32  prev_snd_una,
u8 is_dack 
)
static

Checks if ack is a congestion control event.

Definition at line 498 of file tcp_input.c.

+ Here is the call graph for this function:

+ Here is the caller graph for this function:

static u8 tcp_ack_is_dupack ( tcp_connection_t tc,
vlib_buffer_t b,
u32  prev_snd_wnd,
u32  prev_snd_una 
)
static

Check if duplicate ack as per RFC5681 Sec.

2

Definition at line 485 of file tcp_input.c.

+ Here is the caller graph for this function:

static int tcp_can_delack ( tcp_connection_t tc)
inlinestatic

Check if ACK could be delayed.

If ack can be delayed, it should return true for a full frame. If we're always acking return 0.

Definition at line 1415 of file tcp_input.c.

+ Here is the call graph for this function:

+ Here is the caller graph for this function:

static void tcp_cc_congestion_undo ( tcp_connection_t tc)
static

Definition at line 904 of file tcp_input.c.

+ Here is the call graph for this function:

+ Here is the caller graph for this function:

void tcp_cc_fastrecovery_exit ( tcp_connection_t tc)

Definition at line 894 of file tcp_input.c.

+ Here is the caller graph for this function:

static void tcp_cc_handle_event ( tcp_connection_t tc,
u32  is_dack 
)
static

One function to rule them all ...

and in the darkness bind them

Definition at line 985 of file tcp_input.c.

+ Here is the call graph for this function:

+ Here is the caller graph for this function:

void tcp_cc_init ( tcp_connection_t tc)

Definition at line 1138 of file tcp_input.c.

+ Here is the call graph for this function:

+ Here is the caller graph for this function:

void tcp_cc_init_congestion ( tcp_connection_t tc)

Definition at line 875 of file tcp_input.c.

+ Here is the caller graph for this function:

static u8 tcp_cc_is_spurious_retransmit ( tcp_connection_t tc)
static

Definition at line 917 of file tcp_input.c.

+ Here is the caller graph for this function:

int tcp_cc_recover ( tcp_connection_t tc)

Definition at line 925 of file tcp_input.c.

+ Here is the call graph for this function:

+ Here is the caller graph for this function:

static void tcp_cc_recovery_exit ( tcp_connection_t tc)
static

Definition at line 884 of file tcp_input.c.

+ Here is the call graph for this function:

+ Here is the caller graph for this function:

static void tcp_cc_update ( tcp_connection_t tc,
vlib_buffer_t b 
)
static

Definition at line 947 of file tcp_input.c.

+ Here is the caller graph for this function:

static void tcp_dequeue_acked ( tcp_connection_t tc,
u32  ack 
)
static

Dequeue bytes that have been acked and while at it update RTT estimates.

Definition at line 465 of file tcp_input.c.

+ Here is the call graph for this function:

+ Here is the caller graph for this function:

static void tcp_dispatch_table_init ( tcp_main_t tm)
static

Definition at line 2869 of file tcp_input.c.

+ Here is the caller graph for this function:

static void tcp_established_inc_counter ( vlib_main_t vm,
u8  is_ip4,
u8  evt,
u8  val 
)
inlinestatic

Definition at line 1559 of file tcp_input.c.

+ Here is the call graph for this function:

+ Here is the caller graph for this function:

static void tcp_estimate_rtt ( tcp_connection_t tc,
u32  mrtt 
)
static

Compute smoothed RTT as per VJ's '88 SIGCOMM and RFC6298.

Note that although the original article, srtt and rttvar are scaled to minimize round-off errors, here we don't. Instead, we rely on better precision time measurements.

TODO support us rtt resolution

Definition at line 379 of file tcp_input.c.

+ Here is the caller graph for this function:

clib_error_t* tcp_input_init ( vlib_main_t vm)

Definition at line 2936 of file tcp_input.c.

+ Here is the call graph for this function:

int tcp_options_parse ( tcp_header_t th,
tcp_options_t to 
)

Parse TCP header options.

Parameters
thTCP header
toTCP options data structure to be populated
Returns
-1 if parsing failed

Definition at line 123 of file tcp_input.c.

+ Here is the caller graph for this function:

static int tcp_rcv_ack ( tcp_connection_t tc,
vlib_buffer_t b,
tcp_header_t th,
u32 next,
u32 error 
)
static

Process incoming ACK.

Definition at line 1148 of file tcp_input.c.

+ Here is the call graph for this function:

+ Here is the caller graph for this function:

static int tcp_rcv_ack_is_acceptable ( tcp_connection_t tc0,
vlib_buffer_t tb0 
)
inlinestatic

Definition at line 362 of file tcp_input.c.

+ Here is the caller graph for this function:

void tcp_rcv_sacks ( tcp_connection_t tc,
u32  ack 
)

Definition at line 686 of file tcp_input.c.

+ Here is the call graph for this function:

+ Here is the caller graph for this function:

static int tcp_segment_check_paws ( tcp_connection_t tc)
inlinestatic

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

Definition at line 232 of file tcp_input.c.

+ Here is the caller graph for this function:

static u8 tcp_segment_in_rcv_wnd ( tcp_connection_t tc,
u32  seq,
u32  end_seq 
)
inlinestatic

Validate segment sequence number.

As per RFC793:

Segment Receive Test Length Window


0 0 SEG.SEQ = RCV.NXT 0 >0 RCV.NXT =< SEG.SEQ < RCV.NXT+RCV.WND >0 0 not acceptable >0 >0 RCV.NXT =< SEG.SEQ < RCV.NXT+RCV.WND or RCV.NXT =< SEG.SEQ+SEG.LEN-1 < RCV.NXT+RCV.WND

This ultimately consists in checking if segment falls within the window. The one important difference compared to RFC793 is that we use rcv_las, or the rcv_nxt at last ack sent instead of rcv_nxt since that's the peer's reference when computing our receive window.

This: seq_leq (end_seq, tc->rcv_las + tc->rcv_wnd) && seq_geq (seq, tc->rcv_las) however, is too strict when we have retransmits. Instead we just check that the seq is not beyond the right edge and that the end of the segment is not less than the left edge.

N.B. rcv_nxt and rcv_wnd are both updated in this node if acks are sent, so use rcv_nxt in the right edge window test instead of rcv_las.

Definition at line 109 of file tcp_input.c.

+ Here is the caller graph for this function:

static int tcp_segment_rcv ( tcp_main_t tm,
tcp_connection_t tc,
vlib_buffer_t b,
u16  n_data_bytes,
u32 next0 
)
static

Definition at line 1431 of file tcp_input.c.

+ Here is the call graph for this function:

+ Here is the caller graph for this function:

static int tcp_segment_validate ( vlib_main_t vm,
tcp_connection_t tc0,
vlib_buffer_t b0,
tcp_header_t th0,
u32 next0 
)
static

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 does the processing associated to the first four steps (ignoring security and precedence): sequence number, rst bit and syn bit checks.

Returns
0 if segments passes validation.

Definition at line 269 of file tcp_input.c.

+ Here is the call graph for this function:

+ Here is the caller graph for this function:

static int tcp_session_enqueue_data ( tcp_connection_t tc,
vlib_buffer_t b,
u16  data_len 
)
inlinestatic

Enqueue data for delivery to application.

Definition at line 1299 of file tcp_input.c.

+ Here is the call graph for this function:

+ Here is the caller graph for this function:

static int tcp_session_enqueue_ooo ( tcp_connection_t tc,
vlib_buffer_t b,
u16  data_len 
)
inlinestatic

Enqueue out-of-order data.

Definition at line 1358 of file tcp_input.c.

+ Here is the call graph for this function:

+ Here is the caller graph for this function:

void tcp_set_rx_trace_data ( tcp_rx_trace_t t0,
tcp_connection_t tc0,
tcp_header_t th0,
vlib_buffer_t b0,
u8  is_ip4 
)

Definition at line 1544 of file tcp_input.c.

+ Here is the call graph for this function:

+ Here is the caller graph for this function:

static u8 tcp_should_fastrecover ( tcp_connection_t tc)
static

Definition at line 975 of file tcp_input.c.

+ Here is the call graph for this function:

+ Here is the caller graph for this function:

static u8 tcp_should_fastrecover_sack ( tcp_connection_t tc)
static

Definition at line 969 of file tcp_input.c.

+ Here is the caller graph for this function:

void tcp_update_rto ( tcp_connection_t tc)

Definition at line 405 of file tcp_input.c.

+ Here is the caller graph for this function:

static int tcp_update_rtt ( tcp_connection_t tc,
u32  ack 
)
static

Update RTT estimate and RTO timer.

Measure RTT: We have two sources of RTT measurements: TSOPT and ACK timing. Middle boxes are known to fiddle with TCP options so we should give higher priority to ACK timing.

return 1 if valid rtt 0 otherwise

Definition at line 420 of file tcp_input.c.

+ Here is the call graph for this function:

+ Here is the caller graph for this function:

void tcp_update_sack_list ( tcp_connection_t tc,
u32  start,
u32  end 
)

Build SACK list as per RFC2018.

Makes sure the first block contains the segment that generated the current ACK and the following ones are the ones most recently reported in SACK blocks.

Parameters
tcTCP connection for which the SACK list is updated
startStart sequence number of the newest SACK block
endEnd sequence of the newest SACK block

Definition at line 1247 of file tcp_input.c.

+ Here is the caller graph for this function:

static void tcp_update_snd_wnd ( tcp_connection_t tc,
u32  seq,
u32  ack,
u32  snd_wnd 
)
static

Try to update snd_wnd based on feedback received from peer.

If successful, and new window is 'effectively' 0, activate persist timer.

Definition at line 843 of file tcp_input.c.

+ Here is the call graph for this function:

+ Here is the caller graph for this function:

static void tcp_update_timestamp ( tcp_connection_t tc,
u32  seq,
u32  seq_end 
)
inlinestatic

Update tsval recent.

Definition at line 242 of file tcp_input.c.

+ Here is the call graph for this function:

+ Here is the caller graph for this function:

VLIB_NODE_FUNCTION_MULTIARCH ( tcp4_established_node  ,
tcp4_established   
)

+ Here is the caller graph for this function:

VLIB_NODE_FUNCTION_MULTIARCH ( tcp6_established_node  ,
tcp6_established   
)
VLIB_NODE_FUNCTION_MULTIARCH ( tcp4_syn_sent_node  ,
tcp4_syn_sent   
)
VLIB_NODE_FUNCTION_MULTIARCH ( tcp6_syn_sent_node  ,
tcp6_syn_sent_rcv   
)
VLIB_NODE_FUNCTION_MULTIARCH ( tcp4_rcv_process_node  ,
tcp4_rcv_process   
)
VLIB_NODE_FUNCTION_MULTIARCH ( tcp6_rcv_process_node  ,
tcp6_rcv_process   
)
VLIB_NODE_FUNCTION_MULTIARCH ( tcp4_listen_node  ,
tcp4_listen   
)
VLIB_NODE_FUNCTION_MULTIARCH ( tcp6_listen_node  ,
tcp6_listen   
)
VLIB_NODE_FUNCTION_MULTIARCH ( tcp4_input_node  ,
tcp4_input   
)
VLIB_NODE_FUNCTION_MULTIARCH ( tcp6_input_node  ,
tcp6_input   
)

Variable Documentation

vlib_node_registration_t tcp4_established_node
Initial value:
=
{
.function = tcp4_established,
.name = "tcp4-established",
.vector_size = sizeof (u32),
.n_errors = TCP_N_ERROR,
.error_strings = tcp_error_strings,
.n_next_nodes = TCP_ESTABLISHED_N_NEXT,
.next_nodes =
{
#define _(s,n)
},
.format_trace = format_tcp_rx_trace_short,
}
unsigned int u32
Definition: types.h:88
static uword tcp4_established(vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *from_frame)
Definition: tcp_input.c:1684
#define foreach_tcp_state_next
Definition: tcp_input.c:29
u8 * format_tcp_rx_trace_short(u8 *s, va_list *args)
Definition: tcp_input.c:1529
static char * tcp_error_strings[]
Definition: tcp_input.c:22

(constructor) VLIB_REGISTER_NODE (tcp4_established_node)

Definition at line 78 of file tcp_input.c.

vlib_node_registration_t tcp4_input_node
Initial value:
=
{
.function = tcp4_input,
.name = "tcp4-input",
.vector_size = sizeof (u32),
.n_errors = TCP_N_ERROR,
.error_strings = tcp_error_strings,
.n_next_nodes = TCP_INPUT_N_NEXT,
.next_nodes =
{
#define _(s,n)
},
.format_buffer = format_tcp_header,
.format_trace = format_tcp_rx_trace,
}
u8 * format_tcp_rx_trace(u8 *s, va_list *args)
Definition: tcp_input.c:1513
#define foreach_tcp4_input_next
Definition: tcp_input.c:2644
format_function_t format_tcp_header
Definition: format.h:102
unsigned int u32
Definition: types.h:88
static uword tcp4_input(vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *from_frame)
Definition: tcp_input.c:2809
static char * tcp_error_strings[]
Definition: tcp_input.c:22

(constructor) VLIB_REGISTER_NODE (tcp4_input_node)

Definition at line 2630 of file tcp_input.c.

vlib_node_registration_t tcp4_listen_node
Initial value:
=
{
.function = tcp4_listen,
.name = "tcp4-listen",
.vector_size = sizeof (u32),
.n_errors = TCP_N_ERROR,
.error_strings = tcp_error_strings,
.n_next_nodes = TCP_LISTEN_N_NEXT,
.next_nodes =
{
#define _(s,n)
},
.format_trace = format_tcp_rx_trace_short,
}
static uword tcp4_listen(vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *from_frame)
Definition: tcp_input.c:2573
unsigned int u32
Definition: types.h:88
#define foreach_tcp_state_next
Definition: tcp_input.c:29
u8 * format_tcp_rx_trace_short(u8 *s, va_list *args)
Definition: tcp_input.c:1529
static char * tcp_error_strings[]
Definition: tcp_input.c:22

(constructor) VLIB_REGISTER_NODE (tcp4_listen_node)

Definition at line 2410 of file tcp_input.c.

vlib_node_registration_t tcp4_rcv_process_node
Initial value:
=
{
.function = tcp4_rcv_process,
.name = "tcp4-rcv-process",
.vector_size = sizeof (u32),
.n_errors = TCP_N_ERROR,
.error_strings = tcp_error_strings,
.n_next_nodes = TCP_RCV_PROCESS_N_NEXT,
.next_nodes =
{
#define _(s,n)
},
.format_trace = format_tcp_rx_trace_short,
}
unsigned int u32
Definition: types.h:88
#define foreach_tcp_state_next
Definition: tcp_input.c:29
static uword tcp4_rcv_process(vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *from_frame)
Definition: tcp_input.c:2353
u8 * format_tcp_rx_trace_short(u8 *s, va_list *args)
Definition: tcp_input.c:1529
static char * tcp_error_strings[]
Definition: tcp_input.c:22

(constructor) VLIB_REGISTER_NODE (tcp4_rcv_process_node)

Definition at line 2367 of file tcp_input.c.

vlib_node_registration_t tcp4_syn_sent_node
Initial value:
=
{
.function = tcp4_syn_sent,
.name = "tcp4-syn-sent",
.vector_size = sizeof (u32),
.n_errors = TCP_N_ERROR,
.error_strings = tcp_error_strings,
.n_next_nodes = TCP_SYN_SENT_N_NEXT,
.next_nodes =
{
#define _(s,n)
},
.format_trace = format_tcp_rx_trace_short,
}
static uword tcp4_syn_sent(vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *from_frame)
Definition: tcp_input.c:1993
unsigned int u32
Definition: types.h:88
#define foreach_tcp_state_next
Definition: tcp_input.c:29
u8 * format_tcp_rx_trace_short(u8 *s, va_list *args)
Definition: tcp_input.c:1529
static char * tcp_error_strings[]
Definition: tcp_input.c:22

(constructor) VLIB_REGISTER_NODE (tcp4_syn_sent_node)

Definition at line 1742 of file tcp_input.c.

vlib_node_registration_t tcp6_established_node
Initial value:
=
{
.function = tcp6_established,
.name = "tcp6-established",
.vector_size = sizeof (u32),
.n_errors = TCP_N_ERROR,
.error_strings = tcp_error_strings,
.n_next_nodes = TCP_ESTABLISHED_N_NEXT,
.next_nodes =
{
#define _(s,n)
},
.format_trace = format_tcp_rx_trace_short,
}
unsigned int u32
Definition: types.h:88
static uword tcp6_established(vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *from_frame)
Definition: tcp_input.c:1691
#define foreach_tcp_state_next
Definition: tcp_input.c:29
u8 * format_tcp_rx_trace_short(u8 *s, va_list *args)
Definition: tcp_input.c:1529
static char * tcp_error_strings[]
Definition: tcp_input.c:22

(constructor) VLIB_REGISTER_NODE (tcp6_established_node)

Definition at line 79 of file tcp_input.c.

vlib_node_registration_t tcp6_input_node
Initial value:
=
{
.function = tcp6_input,
.name = "tcp6-input",
.vector_size = sizeof (u32),
.n_errors = TCP_N_ERROR,
.error_strings = tcp_error_strings,
.n_next_nodes = TCP_INPUT_N_NEXT,
.next_nodes =
{
#define _(s,n)
},
.format_buffer = format_tcp_header,
.format_trace = format_tcp_rx_trace,
}
static uword tcp6_input(vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *from_frame)
Definition: tcp_input.c:2816
u8 * format_tcp_rx_trace(u8 *s, va_list *args)
Definition: tcp_input.c:1513
#define foreach_tcp6_input_next
Definition: tcp_input.c:2652
format_function_t format_tcp_header
Definition: format.h:102
unsigned int u32
Definition: types.h:88
static char * tcp_error_strings[]
Definition: tcp_input.c:22

(constructor) VLIB_REGISTER_NODE (tcp6_input_node)

Definition at line 2631 of file tcp_input.c.

vlib_node_registration_t tcp6_listen_node
Initial value:
=
{
.function = tcp6_listen,
.name = "tcp6-listen",
.vector_size = sizeof (u32),
.n_errors = TCP_N_ERROR,
.error_strings = tcp_error_strings,
.n_next_nodes = TCP_LISTEN_N_NEXT,
.next_nodes =
{
#define _(s,n)
},
.format_trace = format_tcp_rx_trace_short,
}
static uword tcp6_listen(vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *from_frame)
Definition: tcp_input.c:2580
unsigned int u32
Definition: types.h:88
#define foreach_tcp_state_next
Definition: tcp_input.c:29
u8 * format_tcp_rx_trace_short(u8 *s, va_list *args)
Definition: tcp_input.c:1529
static char * tcp_error_strings[]
Definition: tcp_input.c:22

(constructor) VLIB_REGISTER_NODE (tcp6_listen_node)

Definition at line 2411 of file tcp_input.c.

vlib_node_registration_t tcp6_rcv_process_node
Initial value:
=
{
.function = tcp6_rcv_process,
.name = "tcp6-rcv-process",
.vector_size = sizeof (u32),
.n_errors = TCP_N_ERROR,
.error_strings = tcp_error_strings,
.n_next_nodes = TCP_RCV_PROCESS_N_NEXT,
.next_nodes =
{
#define _(s,n)
},
.format_trace = format_tcp_rx_trace_short,
}
static uword tcp6_rcv_process(vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *from_frame)
Definition: tcp_input.c:2360
unsigned int u32
Definition: types.h:88
#define foreach_tcp_state_next
Definition: tcp_input.c:29
u8 * format_tcp_rx_trace_short(u8 *s, va_list *args)
Definition: tcp_input.c:1529
static char * tcp_error_strings[]
Definition: tcp_input.c:22

(constructor) VLIB_REGISTER_NODE (tcp6_rcv_process_node)

Definition at line 2389 of file tcp_input.c.

vlib_node_registration_t tcp6_syn_sent_node
Initial value:
=
{
.function = tcp6_syn_sent_rcv,
.name = "tcp6-syn-sent",
.vector_size = sizeof (u32),
.n_errors = TCP_N_ERROR,
.error_strings = tcp_error_strings,
.n_next_nodes = TCP_SYN_SENT_N_NEXT,
.next_nodes =
{
#define _(s,n)
},
.format_trace = format_tcp_rx_trace_short,
}
static uword tcp6_syn_sent_rcv(vlib_main_t *vm, vlib_node_runtime_t *node, vlib_frame_t *from_frame)
Definition: tcp_input.c:2000
unsigned int u32
Definition: types.h:88
#define foreach_tcp_state_next
Definition: tcp_input.c:29
u8 * format_tcp_rx_trace_short(u8 *s, va_list *args)
Definition: tcp_input.c:1529
static char * tcp_error_strings[]
Definition: tcp_input.c:22

(constructor) VLIB_REGISTER_NODE (tcp6_syn_sent_node)

Definition at line 1743 of file tcp_input.c.

char* tcp_error_strings[]
static
Initial value:
= {
#define tcp_error(n,s)
}

Definition at line 22 of file tcp_input.c.