retry.c File Reference

Binary IO abstractions for retrying packets. More...

#include <freeradius-devel/bio/bio_priv.h>
#include <freeradius-devel/bio/null.h>
#include <freeradius-devel/bio/buf.h>
#include <freeradius-devel/util/rb.h>
#include <freeradius-devel/util/dlist.h>
#include <freeradius-devel/bio/retry.h>

Include dependency graph for retry.c:

Go to the source code of this file.

Data Structures
struct	fr_bio_retry_entry_s
union	fr_bio_retry_entry_s.__unnamed10__
struct	fr_bio_retry_s

Macros
#define	_BIO_RETRY_PRIVATE
#define	fr_bio_retry_timer_clear(_x)

Typedefs
typedef struct fr_bio_retry_list_s	fr_bio_retry_list_t
typedef struct fr_bio_retry_s	fr_bio_retry_t

Functions
static int8_t	_expiry_cmp (void const *one, void const *two)
static int8_t	_next_retry_cmp (void const *one, void const *two)
fr_bio_t *	fr_bio_retry_alloc (TALLOC_CTX *ctx, size_t max_saved, fr_bio_retry_sent_t sent, fr_bio_retry_response_t response, fr_bio_retry_rewrite_t rewrite, fr_bio_retry_release_t release, fr_bio_retry_config_t const *cfg, fr_bio_t *next)
	Allocate a fr_bio_retry_t. More...
static int	fr_bio_retry_destructor (fr_bio_retry_t *my)
	Cancel all outstanding packets. More...
int	fr_bio_retry_entry_cancel (fr_bio_t *bio, fr_bio_retry_entry_t *item)
	Cancel one item. More...
const fr_retry_t *	fr_bio_retry_entry_info (UNUSED fr_bio_t *bio, fr_bio_retry_entry_t *item)
	Allow the callbacks / application to know when things are being retried. More...
int	fr_bio_retry_entry_init (UNUSED fr_bio_t *bio, fr_bio_retry_entry_t *item, fr_retry_config_t const *cfg)
	Set a per-packet retry config. More...
static void	fr_bio_retry_expiry_timer (UNUSED fr_event_list_t *el, fr_time_t now, void *uctx)
	Run an expiry timer event. More...
static int	fr_bio_retry_expiry_timer_reset (fr_bio_retry_t *my)
	Reset the expiry timer after expiring one element. More...
fr_bio_retry_info_t const *	fr_bio_retry_info (fr_bio_t *bio)
fr_bio_retry_entry_t *	fr_bio_retry_item_reserve (fr_bio_t *bio)
	Reserve an entry for later use with fr_bio_retry_rewrite() More...
size_t	fr_bio_retry_outstanding (fr_bio_t *bio)
static ssize_t	fr_bio_retry_read (fr_bio_t *bio, void *packet_ctx, void *buffer, size_t size)
static void	fr_bio_retry_release (fr_bio_retry_t *my, fr_bio_retry_entry_t *item, fr_bio_retry_release_reason_t reason)
	Release an entry back to the free list. More...
ssize_t	fr_bio_retry_rewrite (fr_bio_t *bio, fr_bio_retry_entry_t *item, const void *buffer, size_t size)
	Resend a packet. More...
static ssize_t	fr_bio_retry_save_write (fr_bio_retry_t *my, fr_bio_retry_entry_t *item, ssize_t rcode)
	Save a partial packet when the write becomes blocked. More...
static void	fr_bio_retry_shutdown (fr_bio_t *bio)
	Orderly shutdown. More...
static void	fr_bio_retry_timer (UNUSED fr_event_list_t *el, fr_time_t now, void *uctx)
	Run a timer event. More...
static int	fr_bio_retry_timer_reset (fr_bio_retry_t *my)
	Reset the timer after changing the rb tree. More...
static ssize_t	fr_bio_retry_write (fr_bio_t *bio, void *packet_ctx, void const *buffer, size_t size)
	Write a request, and see if we have a reply. More...
static int	fr_bio_retry_write_blocked (fr_bio_t *bio)
	Writes are blocked. More...
static int	fr_bio_retry_write_delayed (fr_bio_retry_t *my, fr_time_t now)
static ssize_t	fr_bio_retry_write_fatal (fr_bio_t *bio, UNUSED void *packet_ctx, UNUSED void const *buffer, UNUSED size_t size)
	A previous timer write had a fatal error, so we forbid further writes. More...
static int	fr_bio_retry_write_item (fr_bio_retry_t *my, fr_bio_retry_entry_t *item, fr_time_t now)
	Write one item. More...
static ssize_t	fr_bio_retry_write_partial (fr_bio_t *bio, void *packet_ctx, const void *buffer, size_t size)
	There's a partial packet written. More...
static int	fr_bio_retry_write_resume (fr_bio_t *bio)
	Resume writes. More...

Detailed Description

Binary IO abstractions for retrying packets.

Id

a0d3078b8bb4db8ba2a96e7b0d3ef85a54c66f4b

The retry BIO provides a mechanism for the application to send one packet, and then delegate retransmissions to the retry bio.

This BIO will monitor writes, and run callbacks when a packet is sent, received, and released. The application should cache the request and response until the release callback has been run. The BIO will call the application on retries, or when the retransmissions have stopped.

The retry BIO also deals with partially written packets. The BIO takes responsibility for not writing partial packets, which means that requests can be rleeased even if the data has been partially written. The application can also cancel an ongoing retryt entrty at any time.

If something blocks IO, the application should call the blocked / resume functions for this BIO to inform it of IO changes. Otherwise, the only time this BIO blocks is when it runs out of retransmission slots.

There are provisions for application-layer watchdogs, where the application can reserve a retry entry. It can then call the fr_bio_retry_rewrite() function instead of fr_bio_write() to write the watchdog packet. Any retransmission timers for the application-layer watchdog must be handled by the application. The BIO will not retry reserved watchdog requests.

In general, the next BIO after this one should be the memory bio, so that this bio receives only complete packets.

Copyright

2024 Network RADIUS SAS (legal.nosp@m.@net.nosp@m.workr.nosp@m.adiu.nosp@m.s.com)

Definition in file retry.c.

---

Data Structure Documentation

fr_bio_retry_entry_s

struct fr_bio_retry_entry_s

Definition at line 64 of file retry.c.

Collaboration diagram for fr_bio_retry_entry_s:

Data Fields
union fr_bio_retry_entry_s	__unnamed__
uint8_t const *	buffer	cached copy of the packet to send
bool	cancelled	was this item cancelled?
fr_rb_node_t	expiry_node	for expiries
fr_bio_retry_t *	my	so we can get to it from the event timer callback
void *	packet_ctx	packet_ctx from the write() call
bool	reserved	for application-layer watchdog
fr_retry_t	retry	retry timers and counters
fr_retry_t _CONST	retry	retry timers and counters
fr_bio_retry_rewrite_t	rewrite	per-packet rewrite callback
void *	rewrite_ctx	context specifically for rewriting this packet
size_t	size	size of the cached packet
void *	uctx	user-writable context

fr_bio_retry_entry_s.__unnamed10__

union fr_bio_retry_entry_s.__unnamed10__

Definition at line 72 of file retry.c.

Data Fields
fr_rb_node_t	next_retry_node	for retries

fr_bio_retry_s

struct fr_bio_retry_s

Definition at line 89 of file retry.c.

Collaboration diagram for fr_bio_retry_s:

Data Fields
bool	all_used	blocked due to no free entries
fr_bio_buf_t	buffer	to store partial packets
ssize_t	error
fr_event_timer_t const *	ev	we only need one timer event: next time we do something
fr_rb_tree_t	expiry_tree	when packets expire, so that we expire packets when the socket is blocked.
	FR_BIO_COMMON
fr_bio_retry_info_t	info
fr_bio_retry_entry_t *	next_retry_item	for timers
fr_rb_tree_t	next_retry_tree	when packets are retried next
fr_bio_retry_entry_t *	partial	for partial writes
fr_bio_retry_release_t	release	callback to release a request / response pair
fr_bio_retry_response_t	response	callback to see if we got a valid response
fr_retry_config_t	retry_config
fr_bio_retry_rewrite_t	rewrite	optional callback which can change a packet on retry
fr_bio_retry_sent_t	sent	callback for when we successfully sent a packet

Macro Definition Documentation

_BIO_RETRY_PRIVATE

#define _BIO_RETRY_PRIVATE

Definition at line 53 of file retry.c.

fr_bio_retry_timer_clear

#define fr_bio_retry_timer_clear

(

_x

)

Value:

                do { \
                talloc_const_free((_x)->ev); \
                (_x)->next_retry_item = NULL; \
        } while (0)

Definition at line 132 of file retry.c.

Typedef Documentation

fr_bio_retry_list_t

typedef struct fr_bio_retry_list_s fr_bio_retry_list_t

Definition at line 1 of file retry.c.

fr_bio_retry_t

typedef struct fr_bio_retry_s fr_bio_retry_t

Definition at line 1 of file retry.c.

Function Documentation

_expiry_cmp()

static int8_t _expiry_cmp ( void const *  one, void const *  two  )

static

Definition at line 971 of file retry.c.

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_next_retry_cmp()

static int8_t _next_retry_cmp ( void const *  one, void const *  two  )

static

Definition at line 955 of file retry.c.

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fr_bio_retry_alloc()

fr_bio_t* fr_bio_retry_alloc	(	TALLOC_CTX *	ctx,
		size_t	max_saved,
		fr_bio_retry_sent_t	sent,
		fr_bio_retry_response_t	response,
		fr_bio_retry_rewrite_t	rewrite,
		fr_bio_retry_release_t	release,
		fr_bio_retry_config_t const *	cfg,
		fr_bio_t *	next
	)

Allocate a fr_bio_retry_t.

Definition at line 1087 of file retry.c.

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fr_bio_retry_destructor()

static int fr_bio_retry_destructor ( fr_bio_retry_t *  my )

static

Cancel all outstanding packets.

Definition at line 1055 of file retry.c.

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fr_bio_retry_entry_cancel()

int fr_bio_retry_entry_cancel	(	fr_bio_t *	bio,
		fr_bio_retry_entry_t *	item
	)

Cancel one item.

If "item" is NULL, the last entry in the timer tree is cancelled.

Parameters

bio	the binary IO handler
item	the retry context from fr_bio_retry_sent_t

Returns

• <0 error
• 0 - didn't cancel
• 1 - did cancel

Definition at line 993 of file retry.c.

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fr_bio_retry_entry_info()

const fr_retry_t* fr_bio_retry_entry_info	(	UNUSED fr_bio_t *	bio,
		fr_bio_retry_entry_t *	item
	)

Allow the callbacks / application to know when things are being retried.

This is not initialized util after fr_bio_retry_entry_start() has been called.

Definition at line 1042 of file retry.c.

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fr_bio_retry_entry_init()

int fr_bio_retry_entry_init	(	UNUSED fr_bio_t *	bio,
		fr_bio_retry_entry_t *	item,
		fr_retry_config_t const *	cfg
	)

Set a per-packet retry config.

This function should be called from the fr_bio_retry_sent_t callback to set a unique retry timer for this packet. If no retry configuration is set, then the main one from the alloc() function is used.

Definition at line 1025 of file retry.c.

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fr_bio_retry_expiry_timer()

static void fr_bio_retry_expiry_timer ( UNUSED fr_event_list_t *  el, fr_time_t  now, void *  uctx  )

static

Run an expiry timer event.

Definition at line 630 of file retry.c.

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fr_bio_retry_expiry_timer_reset()

static int fr_bio_retry_expiry_timer_reset ( fr_bio_retry_t *  my )

static

Reset the expiry timer after expiring one element.

Definition at line 140 of file retry.c.

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fr_bio_retry_info()

fr_bio_retry_info_t const* fr_bio_retry_info

(

fr_bio_t *

bio

)

Definition at line 1158 of file retry.c.

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fr_bio_retry_item_reserve()

fr_bio_retry_entry_t* fr_bio_retry_item_reserve

(

fr_bio_t *

bio

)

Reserve an entry for later use with fr_bio_retry_rewrite()

So that application-layer watchdogs can bypass the normal write / retry routines.

Definition at line 1184 of file retry.c.

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fr_bio_retry_outstanding()

size_t fr_bio_retry_outstanding

(

fr_bio_t *

bio

)

Definition at line 1165 of file retry.c.

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fr_bio_retry_read()

static ssize_t fr_bio_retry_read ( fr_bio_t *  bio, void *  packet_ctx, void *  buffer, size_t  size  )

static

Definition at line 851 of file retry.c.

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fr_bio_retry_release()

static void fr_bio_retry_release ( fr_bio_retry_t *  my, fr_bio_retry_entry_t *  item, fr_bio_retry_release_reason_t  reason  )

static

Release an entry back to the free list.

Definition at line 212 of file retry.c.

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fr_bio_retry_rewrite()

ssize_t fr_bio_retry_rewrite	(	fr_bio_t *	bio,
		fr_bio_retry_entry_t *	item,
		const void *	buffer,
		size_t	size
	)

Resend a packet.

This function should be called by the rewrite() callback, after (possibly) re-encoding the packet.

Parameters

bio	the binary IO handler
item	the retry context from fr_bio_retry_sent_t
buffer	raw data for the packet. May be NULL, in which case the previous packet is retried
size	size of the raw data

Returns

• <0 on error
• 0 for "wrote no data"
• >0 for "wrote data".

Definition at line 554 of file retry.c.

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fr_bio_retry_save_write()

static ssize_t fr_bio_retry_save_write ( fr_bio_retry_t *  my, fr_bio_retry_entry_t *  item, ssize_t  rcode  )

static

Save a partial packet when the write becomes blocked.

Definition at line 503 of file retry.c.

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fr_bio_retry_shutdown()

static void fr_bio_retry_shutdown ( fr_bio_t *  bio )

static

Orderly shutdown.

Definition at line 1077 of file retry.c.

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fr_bio_retry_timer()

static void fr_bio_retry_timer ( UNUSED fr_event_list_t *  el, fr_time_t  now, void *  uctx  )

static

Run a timer event.

Usually to write out another packet.

Definition at line 669 of file retry.c.

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fr_bio_retry_timer_reset()

static int fr_bio_retry_timer_reset ( fr_bio_retry_t *  my )

static

Reset the timer after changing the rb tree.

Definition at line 173 of file retry.c.

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fr_bio_retry_write()

static ssize_t fr_bio_retry_write ( fr_bio_t *  bio, void *  packet_ctx, void const *  buffer, size_t  size  )

static

Write a request, and see if we have a reply.

Definition at line 717 of file retry.c.

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fr_bio_retry_write_blocked()

static int fr_bio_retry_write_blocked ( fr_bio_t *  bio )

static

Writes are blocked.

Definition at line 278 of file retry.c.

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fr_bio_retry_write_delayed()

static int fr_bio_retry_write_delayed ( fr_bio_retry_t *  my, fr_time_t  now  )

static

Definition at line 375 of file retry.c.

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fr_bio_retry_write_fatal()

static ssize_t fr_bio_retry_write_fatal ( fr_bio_t *  bio, UNUSED void *  packet_ctx, UNUSED void const *  buffer, UNUSED size_t  size  )

static

A previous timer write had a fatal error, so we forbid further writes.

Definition at line 616 of file retry.c.

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fr_bio_retry_write_item()

static int fr_bio_retry_write_item ( fr_bio_retry_t *  my, fr_bio_retry_entry_t *  item, fr_time_t  now  )

static

Write one item.

Returns

• <0 on error
• 0 for "can't write any more"
• 1 for "wrote a packet"

Definition at line 303 of file retry.c.

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fr_bio_retry_write_partial()

static ssize_t fr_bio_retry_write_partial ( fr_bio_t *  bio, void *  packet_ctx, const void *  buffer, size_t  size  )

static

There's a partial packet written.

Write all of that one first, before writing another packet.

The packet can either be cancelled, or IO blocked. In either case, we must write the full packet before going on to the next one, OR retrying another packet.

Definition at line 442 of file retry.c.

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fr_bio_retry_write_resume()

static int fr_bio_retry_write_resume ( fr_bio_t *  bio )

static

Resume writes.

On resume, we try to flush any pending packets which should have been sent.

Definition at line 418 of file retry.c.

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