cluster.c File Reference

#include <freeradius-devel/util/debug.h>
#include <freeradius-devel/server/cf_parse.h>
#include <freeradius-devel/util/fifo.h>
#include <freeradius-devel/util/misc.h>
#include <freeradius-devel/util/rand.h>
#include <freeradius-devel/util/time.h>
#include "config.h"
#include "base.h"
#include "cluster.h"
#include "crc16.h"

Include dependency graph for cluster.c:

Go to the source code of this file.

Data Structures
struct	cluster_nodes_live_t
	Live nodes data, used to perform weighted random selection of alternative nodes. More...
struct	cluster_nodes_live_t.node
struct	fr_redis_cluster
	A redis cluster. More...
struct	fr_redis_cluster_key_slot_s
	Indexes in the fr_redis_cluster_node_t array for a single key slot. More...
struct	fr_redis_cluster_node_s
	A Redis cluster node. More...

Macros
#define	CLOSED_PERIOD   10000
	How recently must the closed have. More...
#define	CLOSED_WEIGHT   1
	What weight to give to nodes that. More...
#define	FAILED_PERIOD   10000
	How recently must the spawn failure. More...
#define	FAILED_WEIGHT   1
	What weight to give to nodes that. More...
#define	KEY_SLOTS   16384
	Maximum number of keyslots (should not change). More...
#define	MAX_SLAVES   5
	Maximum number of slaves associated. More...
#define	RELEASED_MIN_WEIGHT   1000
	Minimum weight to assign to node. More...
#define	RELEASED_PERIOD   10000
	Period after which we don't care. More...
#define	SET_ACTIVE(_node)
#define	SET_ADDR(_addr, _map)
#define	SET_INACTIVE(_node)

Functions
static int	_cluster_conn_free (fr_redis_conn_t *conn)
	Callback for freeing a Redis connection. More...
static int8_t	_cluster_node_cmp (void const *one, void const *two)
	Compare two redis nodes to check equality. More...
static void	_cluster_node_conf_apply (fr_pool_t *pool, void *opaque)
	Reconnect callback to apply new pool config. More...
static int	_fr_redis_cluster_free (fr_redis_cluster_t *cluster)
	Destroy mutex associated with cluster slots structure. More...
static uint16_t	cluster_key_hash (uint8_t const *key, size_t key_len)
	Resolve key to key slot. More...
static fr_redis_cluster_rcode_t	cluster_map_apply (fr_redis_cluster_t *cluster, redisReply *reply)
	Apply a cluster map received from a cluster node. More...
static fr_redis_cluster_rcode_t	cluster_map_get (redisReply **out, fr_redis_conn_t *conn)
	Learn a new cluster layout by querying the node that issued the -MOVE. More...
static int	cluster_map_node_validate (redisReply *node, int map_idx, int node_idx)
	Validate a cluster map node entry. More...
static fr_redis_cluster_rcode_t	cluster_node_conf_from_redirect (uint16_t *key_slot, fr_socket_t *node_addr, redisReply *redirect)
	Parse a -MOVED or -ASK redirect. More...
static fr_redis_cluster_rcode_t	cluster_node_connect (fr_redis_cluster_t *cluster, fr_redis_cluster_node_t *node)
	Establish a connection to a cluster node. More...
static int	cluster_node_find_live (fr_redis_cluster_node_t **live_node, fr_redis_conn_t **live_conn, request_t *request, fr_redis_cluster_t *cluster, fr_redis_cluster_node_t *skip)
	Attempt to find a live pool in the cluster. More...
static fr_redis_cluster_rcode_t	cluster_node_ping (request_t *request, fr_redis_cluster_node_t *node, fr_redis_conn_t *conn)
	Issue a ping request against a cluster node. More...
static int	cluster_node_pool_health (fr_time_t now, fr_pool_state_t const *state)
	Try to determine the health of a cluster node passively by examining its pool state. More...
static fr_redis_cluster_rcode_t	cluster_redirect (fr_redis_cluster_node_t **out, fr_redis_cluster_t *cluster, redisReply *reply)
	Retrieve or associate a node with the server indicated in the redirect. More...
fr_redis_cluster_t *	fr_redis_cluster_alloc (TALLOC_CTX *ctx, CONF_SECTION *module, fr_redis_conf_t *conf, bool triggers_enabled, char const *log_prefix, char const *trigger_prefix, fr_pair_list_t *trigger_args)
	Allocate and initialise a new cluster structure. More...
void *	fr_redis_cluster_conn_create (TALLOC_CTX *ctx, void *instance, fr_time_delta_t timeout)
	Create a new connection to a Redis node. More...
int	fr_redis_cluster_ipaddr (fr_ipaddr_t *out, fr_redis_cluster_node_t const *node)
	Return the ipaddr of a particular node. More...
fr_redis_cluster_node_t const *	fr_redis_cluster_master (fr_redis_cluster_t *cluster, fr_redis_cluster_key_slot_t const *key_slot)
	Return the master node that would be used for a particular key. More...
bool	fr_redis_cluster_min_version (fr_redis_cluster_t *cluster, char const *min_version)
	Check if members of the cluster are above a certain version. More...
ssize_t	fr_redis_cluster_node_addr_by_role (TALLOC_CTX *ctx, fr_socket_t *out[], fr_redis_cluster_t *cluster, bool is_master, bool is_slave)
	Return an array of IP addresses belonging to masters or slaves. More...
int	fr_redis_cluster_pool_by_node_addr (fr_pool_t **pool, fr_redis_cluster_t *cluster, fr_socket_t *node_addr, bool create)
	Get the pool associated with a node in the cluster. More...
int	fr_redis_cluster_port (uint16_t *out, fr_redis_cluster_node_t const *node)
	Return the port of a particular node. More...
fr_redis_cluster_rcode_t	fr_redis_cluster_remap (request_t *request, fr_redis_cluster_t *cluster, fr_redis_conn_t *conn)
	Perform a runtime remap of the cluster. More...
fr_redis_cluster_node_t const *	fr_redis_cluster_slave (fr_redis_cluster_t *cluster, fr_redis_cluster_key_slot_t const *key_slot, uint8_t slave_num)
	Return the slave node that would be used for a particular key. More...
fr_redis_cluster_key_slot_t const *	fr_redis_cluster_slot_by_key (fr_redis_cluster_t *cluster, request_t *request, uint8_t const *key, size_t key_len)
	Implements the key slot selection scheme used by freeradius. More...
fr_redis_rcode_t	fr_redis_cluster_state_init (fr_redis_cluster_state_t *state, fr_redis_conn_t **conn, fr_redis_cluster_t *cluster, request_t *request, uint8_t const *key, size_t key_len, bool read_only)
	Resolve a key to a pool, and reserve a connection in that pool. More...
fr_redis_rcode_t	fr_redis_cluster_state_next (fr_redis_cluster_state_t *state, fr_redis_conn_t **conn, fr_redis_cluster_t *cluster, request_t *request, fr_redis_rcode_t status, redisReply **reply)
	Get the next connection to attempt a command against. More...

Variables
fr_table_num_sorted_t const	fr_redis_cluster_rcodes_table []
size_t	fr_redis_cluster_rcodes_table_len = NUM_ELEMENTS(fr_redis_cluster_rcodes_table)

---

Data Structure Documentation

cluster_nodes_live_t

struct cluster_nodes_live_t

Live nodes data, used to perform weighted random selection of alternative nodes.

Definition at line 195 of file cluster.c.

Data Fields
uint8_t	next	Next index in live.
struct cluster_nodes_live_t	node[UINT8_MAX - 1]	Array of live node IDs (and weights).
uint8_t	skip

cluster_nodes_live_t.node

struct cluster_nodes_live_t.node

Definition at line 196 of file cluster.c.

Data Fields
unsigned int	cumulative	Cumulative weight.
uint8_t	id	Node ID.
fr_pool_state_t const *	pool_state	Connection pool stats.

fr_redis_cluster

struct fr_redis_cluster

A redis cluster.

Holds all the structures and collections of nodes, to represent a Redis cluster.

Definition at line 247 of file cluster.c.

Collaboration diagram for fr_redis_cluster:

Data Fields
fr_redis_conf_t *	conf	Base configuration data such as the database number and passwords.
fr_fifo_t *	free_nodes	Queue of free nodes (or nodes waiting to be reused).
fr_redis_cluster_key_slot_t	key_slot[KEY_SLOTS]	Lookup table of slots to pools.
fr_redis_cluster_key_slot_t	key_slot_pending[KEY_SLOTS]	Pending key slot table.
fr_time_t	last_updated	Last time the cluster mappings were updated.
char const *	log_prefix	What to prepend to log messages.
CONF_SECTION *	module	Module configuration.
pthread_mutex_t	mutex	Mutex to synchronise cluster operations.
fr_redis_cluster_node_t *	node	Structure containing a node id, its address and a pool of its connections.
bool	remap_needed	Set true if at least one cluster node is definitely unreachable. Set false on successful remap.
bool	remapping	True when cluster is being remapped.
fr_pair_list_t	trigger_args	Arguments to pass to triggers.
char const *	trigger_prefix	Trigger path.
bool	triggers_enabled	Whether triggers are enabled.
fr_rb_tree_t *	used_nodes	Tree of used nodes.

fr_redis_cluster_key_slot_s

struct fr_redis_cluster_key_slot_s

Indexes in the fr_redis_cluster_node_t array for a single key slot.

When dealing with 16K entries, space is a concern. It's significantly more memory efficient to use 8bit indexes than 64bit pointers for each of the key slot to node mappings.

Definition at line 237 of file cluster.c.

Data Fields
uint8_t	master	R/W node (master) for this key slot.
uint8_t	slave[MAX_SLAVES]	R/O node (slave) for this key slot.
uint8_t	slave_num	Number of slaves associated with this key slot.

fr_redis_cluster_node_s

struct fr_redis_cluster_node_s

A Redis cluster node.

Passed as opaque data to pools which open connection to nodes.

Definition at line 209 of file cluster.c.

Collaboration diagram for fr_redis_cluster_node_s:

Data Fields
fr_socket_t	addr	Current node address.
fr_redis_cluster_t *	cluster	Common configuration (database number, password, etc..).
uint8_t	id	Node ID (index in node array).
bool	is_active	Whether this node is in the active node set.
bool	is_master	Whether this node is a master. This is needed for commands like 'KEYS', which we need to issue to every master in the cluster.
char	name[INET6_ADDRSTRLEN]	Buffer to hold IP string. text for debug messages.
fr_socket_t	pending_addr	New node address to be applied when the pool is reconnected.
fr_pool_t *	pool	Pool associated with this node.
CONF_SECTION *	pool_cs	Pool configuration section associated with node.
fr_rb_node_t	rbnode	Entry into the tree of redis nodes.

Macro Definition Documentation

CLOSED_PERIOD

#define CLOSED_PERIOD   10000

How recently must the closed have.

occurred for us to care.

Definition at line 176 of file cluster.c.

CLOSED_WEIGHT

#define CLOSED_WEIGHT   1

What weight to give to nodes that.

had a connection closed recently.

Definition at line 179 of file cluster.c.

FAILED_PERIOD

#define FAILED_PERIOD   10000

How recently must the spawn failure.

occurred for us to care.

Definition at line 182 of file cluster.c.

FAILED_WEIGHT

#define FAILED_WEIGHT   1

What weight to give to nodes that.

had a spawn failure recently.

Definition at line 185 of file cluster.c.

KEY_SLOTS

#define KEY_SLOTS   16384

Maximum number of keyslots (should not change).

Definition at line 167 of file cluster.c.

MAX_SLAVES

#define MAX_SLAVES   5

Maximum number of slaves associated.

with a keyslot.

Definition at line 170 of file cluster.c.

RELEASED_MIN_WEIGHT

#define RELEASED_MIN_WEIGHT   1000

Minimum weight to assign to node.

Definition at line 191 of file cluster.c.

RELEASED_PERIOD

#define RELEASED_PERIOD   10000

Period after which we don't care.

about when the last connection was released.

Definition at line 189 of file cluster.c.

SET_ACTIVE

#define SET_ACTIVE

(

_node

)

Value:

do { \
        (_node)->is_active = true; \
        fr_rb_insert(cluster->used_nodes, _node); \
        fr_fifo_pop(cluster->free_nodes); \
        active[(_node)->id] = true; \
        rollback[r++] = (_node)->id; \
} while (0)

SET_ADDR

#define SET_ADDR	(		_addr,
			_map
	)

Value:

do { \
        int _ret; \
        _ret = fr_inet_pton(&_addr.inet.dst_ipaddr, _map->element[0]->str, _map->element[0]->len, AF_UNSPEC, true, true);\
        fr_assert(_ret == 0);\
        _addr.inet.dst_port = _map->element[1]->integer; \
} while (0)

SET_INACTIVE

#define SET_INACTIVE

(

_node

)

Value:

do { \
        (_node)->is_active = false; \
        (_node)->is_master = false; \
        fr_rb_delete(cluster->used_nodes, _node); \
        fr_fifo_push(cluster->free_nodes, _node); \
} while (0)

Function Documentation

_cluster_conn_free()

static int _cluster_conn_free ( fr_redis_conn_t *  conn )

static

Callback for freeing a Redis connection.

Parameters

[in]

conn

to free.

Returns

0.

Definition at line 1448 of file cluster.c.

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_cluster_node_cmp()

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

static

Compare two redis nodes to check equality.

Parameters

[in]	one	first node.
[in]	two	second node.

Returns

CMP(one, two)

Definition at line 319 of file cluster.c.

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_cluster_node_conf_apply()

static void _cluster_node_conf_apply ( fr_pool_t *  pool, void *  opaque  )

static

Reconnect callback to apply new pool config.

Parameters

[in]	pool	to apply new configuration to.
[in]	opaque	data passed to the connection pool.

Definition at line 336 of file cluster.c.

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_fr_redis_cluster_free()

static int _fr_redis_cluster_free ( fr_redis_cluster_t *  cluster )

static

Destroy mutex associated with cluster slots structure.

Parameters

cluster

being freed.

Returns

0

Definition at line 2181 of file cluster.c.

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cluster_key_hash()

static uint16_t cluster_key_hash ( uint8_t const *  key, size_t  key_len  )

static

Resolve key to key slot.

Identical to the example implementation, except it uses memchr which will be faster, and isn't so needlessly complex.

Parameters

[in]	key	to resolve.
[in]	key_len	length of key.

Returns

key slot index for the key.

Definition at line 295 of file cluster.c.

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cluster_map_apply()

static fr_redis_cluster_rcode_t cluster_map_apply ( fr_redis_cluster_t *  cluster, redisReply *  reply  )

static

Apply a cluster map received from a cluster node.

Note

Errors may be retrieved with fr_strerror().

Must be called with the cluster mutex held.

Key slot range structure

  [0] -> key slot range 0
      [0] -> key_slot_start
      [1] -> key_slot_end
      [2] -> master_node
          [0] -> master 0 ip (string)
          [1] -> master 0 port (number)
      [3..n] -> slave_node(s)
  [1] -> key slot range 1)
      [0]  -> key_slot_start
      [1] -> key_slot_end
      [2] -> master_node
          [0] -> master 1 ip (string)
          [1] -> master 1 port (number)
      [3..n] -> slave_node(s)
  [n] -> key slot range n
      [0] -> key_slot_start
      [1] -> key_slot_end
      [2] -> master_node
          [0] -> master n ip (string)
          [1] -> master n port (number)
      [3..n] -> slave_node(s)

Parameters

[in,out]	cluster	to apply map to.
[in]	reply	from cluster_map_get.

Returns

• FR_REDIS_CLUSTER_RCODE_SUCCESS on success.
• FR_REDIS_CLUSTER_RCODE_FAILED on failure.
• FR_REDIS_CLUSTER_RCODE_NO_CONNECTION connection failure.
• FR_REDIS_CLUSTER_RCODE_BAD_INPUT if the map didn't provide nodes for all keyslots.

Definition at line 534 of file cluster.c.

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cluster_map_get()

static fr_redis_cluster_rcode_t cluster_map_get ( redisReply **  out, fr_redis_conn_t *  conn  )

static

Learn a new cluster layout by querying the node that issued the -MOVE.

Also validates the response from the Redis cluster, so we can be sure that it's well formed, before doing more expensive operations.

Note

Errors may be retrieved with fr_strerror().

Parameters

[out]	out	Where to write cluster map.
[in]	conn	to use for learning the new cluster map.

Returns

• FR_REDIS_CLUSTER_RCODE_IGNORED if 'cluster slots' returned an error (indicating clustering not supported).
• FR_REDIS_CLUSTER_RCODE_SUCCESS on success.
• FR_REDIS_CLUSTER_RCODE_FAILED if issuing the command resulted in an error.
• FR_REDIS_CLUSTER_RCODE_NO_CONNECTION connection failure.
• FR_REDIS_CLUSTER_RCODE_BAD_INPUT on validation failure (bad data returned from Redis).

Definition at line 860 of file cluster.c.

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cluster_map_node_validate()

static int cluster_map_node_validate ( redisReply *  node, int  map_idx, int  node_idx  )

static

Validate a cluster map node entry.

Note

Errors may be retrieved with fr_strerror().

In a separate function, as it's called for both master and slave nodes.

Parameters

[in]	node	we're validating.
[in]	map_idx	we're processing.
[in]	node_idx	we're processing.

Returns

• FR_REDIS_CLUSTER_RCODE_SUCCESS on success.
• FR_REDIS_CLUSTER_RCODE_BAD_INPUT on validation failure (bad data returned from Redis).

Definition at line 782 of file cluster.c.

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cluster_node_conf_from_redirect()

static fr_redis_cluster_rcode_t cluster_node_conf_from_redirect ( uint16_t *  key_slot, fr_socket_t *  node_addr, redisReply *  redirect  )

static

Parse a -MOVED or -ASK redirect.

Converts the body of the -MOVED or -ASK error into an IPv4/6 address and port.

Parameters

[out]	key_slot	value extracted from redirect string (may be NULL).
[out]	node_addr	Redis node ipaddr and port extracted from redirect string.
[in]	redirect	to process.

Returns

• FR_REDIS_CLUSTER_RCODE_SUCCESS on success.
• FR_REDIS_CLUSTER_RCODE_BAD_INPUT if the server returned an invalid redirect.

Definition at line 443 of file cluster.c.

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cluster_node_connect()

static fr_redis_cluster_rcode_t cluster_node_connect ( fr_redis_cluster_t *  cluster, fr_redis_cluster_node_t *  node  )

static

Establish a connection to a cluster node.

Note

Must be called with the cluster mutex locked.

Configuration to use for the connection must be set in node->pending_addr, not node->cluster->conf.

Parameters

[in]	cluster	to search in.
[in]	node	config.

Returns

• FR_REDIS_CLUSTER_RCODE_SUCCESS on success.
• FR_REDIS_CLUSTER_RCODE_FAILED if the operation failed.

Definition at line 368 of file cluster.c.

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cluster_node_find_live()

static int cluster_node_find_live ( fr_redis_cluster_node_t **  live_node, fr_redis_conn_t **  live_conn, request_t *  request, fr_redis_cluster_t *  cluster, fr_redis_cluster_node_t *  skip  )

static

Attempt to find a live pool in the cluster.

The intent here is to find pools/nodes where a connection was released the shortest time ago. Having a connection be released (vs closed) indicates that the pool is live.

We don't want to have all workers try and grab a connection to this node however, as it may still be dead (we don't know).

So we use an inverse transform sample, to weight the nodes, based on time between now and when the connection was released. Connections released closest to the current time are given a higher weighting.

Weight range is between 1 - 11,000.

• If released > 10.0 seconds ago,information is not valid, weight 500.
• If closed < 10.0 seconds ago, it's a bad pool, weight 1.
• If spawn failed < 10.0 seconds ago, it's a bad pool, weight 1.
• If a connection was released 0.0 seconds ago, weight 11,000.
• If a connection was released 10.0 seconds ago, weight 1000.

Using the above algorithm we use the experience of other workers using the cluster to inform our alternative node selection.

Suggestions on improving live node selection appreciated.

Inverse transform sampling based roughly on the solution from this post: http://stackoverflow.com/questions/17250568/randomly-choosing-from-a-list-with-weighted-probabilities

Wikipedia page here: https://en.wikipedia.org/wiki/Inverse_transform_sampling

Note

Must be called with the cluster mutex free.

Parameters

[out]	live_node	we found.
[out]	live_conn	to that node.
[in]	request	The current request (used for logging).
[in]	cluster	to search for live pools in.
[in]	skip	this node (it's bad).

Returns

0 (iterates over the whole tree).

Definition at line 1307 of file cluster.c.

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cluster_node_ping()

static fr_redis_cluster_rcode_t cluster_node_ping ( request_t *  request, fr_redis_cluster_node_t *  node, fr_redis_conn_t *  conn  )

static

Issue a ping request against a cluster node.

Establishes whether the connection to the node we have is live.

Parameters

request	The current request.
node	to ping.
conn	the connection to ping on.

Returns

• FR_REDIS_CLUSTER_RCODE_BAD_INPUT if we got a bad response.
• FR_REDIS_CLUSTER_RCODE_SUCCESS on success.
• FR_REDIS_CLUSTER_RCODE_NO_CONNECTION on connection down.

Definition at line 1240 of file cluster.c.

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cluster_node_pool_health()

static int cluster_node_pool_health ( fr_time_t  now, fr_pool_state_t const *  state  )

static

Try to determine the health of a cluster node passively by examining its pool state.

Returns an integer value representing the likelihood that the pool is live. Range is between 1 and 11,000.

If a weight of 1 is returned, connections from the pool should be checked (by pinging) before use.

Parameters

now	The current time.
state	of the connection pool.

Returns

• 1 the pool is very likely to be bad.
• 2-11000 the pool is likely to be good, with a higher number indicating higher probability of liveness.

Definition at line 1205 of file cluster.c.

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cluster_redirect()

static fr_redis_cluster_rcode_t cluster_redirect ( fr_redis_cluster_node_t **  out, fr_redis_cluster_t *  cluster, redisReply *  reply  )

static

Retrieve or associate a node with the server indicated in the redirect.

Note

Errors may be retrieved with fr_strerror().

Parameters

[out]	out	Where to write the node representing the redirect server.
[in]	cluster	to draw node from.
[in]	reply	Redis reply containing the redirect information.

Returns

• FR_REDIS_CLUSTER_RCODE_SUCCESS on success.
• FR_REDIS_CLUSTER_RCODE_FAILED no more nodes available.
• FR_REDIS_CLUSTER_RCODE_NO_CONNECTION connection failure.
• FR_REDIS_CLUSTER_RCODE_BAD_INPUT on validation failure (bad data returned from Redis).

Definition at line 1115 of file cluster.c.

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fr_redis_cluster_alloc()

fr_redis_cluster_t* fr_redis_cluster_alloc	(	TALLOC_CTX *	ctx,
		CONF_SECTION *	module,
		fr_redis_conf_t *	conf,
		bool	triggers_enabled,
		char const *	log_prefix,
		char const *	trigger_prefix,
		fr_pair_list_t *	trigger_args
	)

Allocate and initialise a new cluster structure.

This holds all the data necessary to manage a pool of pools for a specific redis cluster.

Note

Will not error out unless cs.pool.start > 0. This is consistent with other pool based modules/code.

Parameters

ctx	to link the lifetime of the cluster structure to.
module	Configuration section to search for 'server' conf pairs in.
conf	Base redis server configuration. Cluster nodes share database number and password.
triggers_enabled	Whether triggers should be enabled.
log_prefix	Custom log prefix. Defaults to rlm_<module> (<instance>) .
trigger_prefix	Custom trigger prefix. Defaults to modules.<module>.pool .
trigger_args	Argument pairs to pass to the trigger in addition to Connection-Pool-Server, and Connection-Pool-Port (which are always set by the cluster code).

Returns

• New fr_redis_cluster_t on success.
• NULL on error.

Definition at line 2257 of file cluster.c.

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fr_redis_cluster_conn_create()

void* fr_redis_cluster_conn_create	(	TALLOC_CTX *	ctx,
		void *	instance,
		fr_time_delta_t	timeout
	)

Create a new connection to a Redis node.

Parameters

[in]	ctx	to allocate connection structure in. Will be freed at the same time as the pool.
[in]	instance	data of type fr_redis_cluster_node_t. Holds parameters for establishing new connection.
[in]	timeout	The maximum time allowed to complete the connection.

Returns

• New fr_redis_conn_t on success.
• NULL on failure.

Definition at line 1464 of file cluster.c.

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fr_redis_cluster_ipaddr()

int fr_redis_cluster_ipaddr	(	fr_ipaddr_t *	out,
		fr_redis_cluster_node_t const *	node
	)

Return the ipaddr of a particular node.

Parameters

[out]	out	Ipaddr of the node.
[in]	node	to get ip address from.

Returns

• 0 on success.
• -1 on failure (node is NULL).

Definition at line 1668 of file cluster.c.

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fr_redis_cluster_master()

fr_redis_cluster_node_t const* fr_redis_cluster_master	(	fr_redis_cluster_t *	cluster,
		fr_redis_cluster_key_slot_t const *	key_slot
	)

Return the master node that would be used for a particular key.

Parameters

[in]	cluster	To resolve key in.
[in]	key_slot	to resolve to node.

Returns

• The current master node.
• NULL if no master node is currently assigned to a particular key slot.

Definition at line 1635 of file cluster.c.

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fr_redis_cluster_min_version()

bool fr_redis_cluster_min_version	(	fr_redis_cluster_t *	cluster,
		char const *	min_version
	)

Check if members of the cluster are above a certain version.

Parameters

cluster	to perform check on.
min_version	that must be found on each node for the check to succeed. Must be in the format <major>.<minor>.<release> .

Returns

• true if all contactable members are above min_version.
• false if at least one member if not above minimum version (use fr_strerror to retrieve node information).

Definition at line 2198 of file cluster.c.

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fr_redis_cluster_node_addr_by_role()

ssize_t fr_redis_cluster_node_addr_by_role	(	TALLOC_CTX *	ctx,
		fr_socket_t *	out[],
		fr_redis_cluster_t *	cluster,
		bool	is_master,
		bool	is_slave
	)

Return an array of IP addresses belonging to masters or slaves.

Note

We return IP addresses as they're safe to use across cluster remaps.

Result array must be freed (talloc_free()) after use.

Parameters

[in]	ctx	to allocate array of IP addresses in.
[out]	out	Where to write the addresses of the nodes.
[in]	cluster	to search for nodes in.
[in]	is_master	If true, include the addresses of all the master nodes.
[in]	is_slave	If true, include the addresses of all the slaves nodes.

Returns

the number of ip addresses written to out.

Definition at line 2134 of file cluster.c.

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fr_redis_cluster_pool_by_node_addr()

int fr_redis_cluster_pool_by_node_addr	(	fr_pool_t **	pool,
		fr_redis_cluster_t *	cluster,
		fr_socket_t *	node_addr,
		bool	create
	)

Get the pool associated with a node in the cluster.

Note

This is used for testing only. It's not ifdef'd out because tests need to run against production builds too.

Parameters

[out]	pool	associated with the node.
[in]	cluster	to search for node in.
[in]	node_addr	to retrieve pool for. Specifies IP and port of node.
[in]	create	Establish a connection to the specified node if it was previously unknown to the cluster client.

Returns

• 0 on success.
• -1 if no such node exists.

Definition at line 2066 of file cluster.c.

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fr_redis_cluster_port()

int fr_redis_cluster_port	(	uint16_t *	out,
		fr_redis_cluster_node_t const *	node
	)

Return the port of a particular node.

Parameters

[out]	out	Port of the node.
[in]	node	to get ip address from.

Returns

• 0 on success.
• -1 on failure (node is NULL).

Definition at line 1685 of file cluster.c.

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fr_redis_cluster_remap()

fr_redis_cluster_rcode_t fr_redis_cluster_remap	(	request_t *	request,
		fr_redis_cluster_t *	cluster,
		fr_redis_conn_t *	conn
	)

Perform a runtime remap of the cluster.

Note

Errors may be retrieved with fr_strerror().

Must be called with the cluster mutex free.

Parameters

[in]	request	The current request.
[in,out]	cluster	to remap.
[in]	conn	to use to query the cluster.

Returns

• FR_REDIS_CLUSTER_RCODE_IGNORED if 'cluster slots' returned an error (indicating clustering not supported).
• FR_REDIS_CLUSTER_RCODE_SUCCESS on success.
• FR_REDIS_CLUSTER_RCODE_FAILED if issuing the 'cluster slots' command resulted in a protocol error.
• FR_REDIS_CLUSTER_RCODE_NO_CONNECTION connection failure.
• FR_REDIS_CLUSTER_RCODE_BAD_INPUT on validation failure (bad data returned from Redis).

Definition at line 1005 of file cluster.c.

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fr_redis_cluster_slave()

fr_redis_cluster_node_t const* fr_redis_cluster_slave	(	fr_redis_cluster_t *	cluster,
		fr_redis_cluster_key_slot_t const *	key_slot,
		uint8_t	slave_num
	)

Return the slave node that would be used for a particular key.

Parameters

[in]	cluster	To resolve key in.
[in]	key_slot	To resolve to node.
[in]	slave_num	0..n.

Returns

• A slave node.
• NULL if no slave node is assigned, or is at the specific key slot.

Definition at line 1651 of file cluster.c.

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fr_redis_cluster_slot_by_key()

fr_redis_cluster_key_slot_t const* fr_redis_cluster_slot_by_key	(	fr_redis_cluster_t *	cluster,
		request_t *	request,
		uint8_t const *	key,
		size_t	key_len
	)

Implements the key slot selection scheme used by freeradius.

Like the scheme in the clustering specification but with some differences if the key is NULL or zero length, then a random keyslot is chosen.

If there's only a single node in the cluster, then we avoid the CRC16 and just use key slot 0.

Parameters

cluster	to determine key slot for.
request	The current request.
key	the key to resolve.
key_len	the length of the key.

Returns

pointer to key slot key resolves to.

Definition at line 1599 of file cluster.c.

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fr_redis_cluster_state_init()

fr_redis_rcode_t fr_redis_cluster_state_init	(	fr_redis_cluster_state_t *	state,
		fr_redis_conn_t **	conn,
		fr_redis_cluster_t *	cluster,
		request_t *	request,
		uint8_t const *	key,
		size_t	key_len,
		bool	read_only
	)

Resolve a key to a pool, and reserve a connection in that pool.

This should be used with fr_redis_cluster_state_next, and fr_redis_command_status, to transparently locate the cluster node we need to perform the operation on.

Example code below shows how this function is used in conjunction with fr_redis_cluster_state_next to follow redirects, and reconnect handles.

int                 s_ret;
redis_conn_state     state;
fr_redis_conn_t      *conn;
redisReply           *reply;
fr_redis_rcode_t     status;
 
for (s_ret = fr_redis_cluster_state_init(&state, &conn, cluster, key, key_len, false);
     s_ret == REDIS_RCODE_TRY_AGAIN,
     s_ret = fr_redis_cluster_state_next(&state, &conn, cluster, request, status, &reply)) {
        reply = redisCommand(conn->handle, "SET foo bar");
        status = fr_redis_command_status(conn, reply);
}
// Reply is freed if ret == REDIS_RCODE_TRY_AGAIN, but left in all other cases to allow error
// processing, or extraction of results.
fr_redis_reply_free(&reply);
if (s_ret != REDIS_RCODE_SUCCESS) {
     // Error
}
// Success

Parameters

[out]	state	to track current pool and various counters, will be initialised.
[out]	conn	Where to write the reserved connection to.
[in]	cluster	of pools.
[in]	request	The current request.
[in]	key	to resolve to a cluster node/pool. If no key is NULL or key_len is 0 a random slot will be chosen.
[in]	key_len	Length of the key.
[in]	read_only	If true, will use random slave pool in preference to the master, falling back to the master if no slaves are available.

Returns

• REDIS_RCODE_TRY_AGAIN - try your command with this connection (provided via command).
• REDIS_RCODE_RECONNECT - when no additional connections available.

Definition at line 1737 of file cluster.c.

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fr_redis_cluster_state_next()

fr_redis_rcode_t fr_redis_cluster_state_next	(	fr_redis_cluster_state_t *	state,
		fr_redis_conn_t **	conn,
		fr_redis_cluster_t *	cluster,
		request_t *	request,
		fr_redis_rcode_t	status,
		redisReply **	reply
	)

Get the next connection to attempt a command against.

Will process reconnect and redirect states performing the actions necessary.

• May trigger a cluster remap on receiving a REDIS_RCODE_MOVE status.
• May perform a temporary redirect on receiving a REDIS_RCODE_ASK status.
• May reserve a new connection on receiving a REDIS_RCODE_RECONNECT status.

If a remap is in progress, has occurred within the last second, has recently failed, or fails, the '-MOVE' will be treated as a temporary redirect (-ASK).

This allows the server to be more responsive during remaps, as unless the worker has been redirected to a node we don't currently have a pool for, it can grab a connection for the node it was redirected to, and continue.

Note

Irrespective of return code, the connection passed via conn will be released, A new connection to attempt command on will be provided via conn.

reply will be automatically freed and set to NULL if a new connection is provided in all other cases, the caller is responsible for freeing the reply.

Parameters

[in,out]	state	containing the current pool, and various counters which control retries, and limit redirects.
[in,out]	conn	we received the '-ASK' or '-MOVE' redirect on. Will be replaced with a connection in the new pool the key points to.
[in]	request	The current request.
[in]	cluster	of pools.
[in]	status	of the last command, must be REDIS_RCODE_MOVE or REDIS_RCODE_ASK.
[in]	reply	from last command. Freed if 0 is returned, else caller must free.

Returns

• REDIS_RCODE_SUCCESS - on success.
• REDIS_RCODE_TRY_AGAIN - try new connection (provided via conn). Will free reply.
• REDIS_RCODE_ERROR - on failure or command error.
• REDIS_RCODE_RECONNECT - when no additional connections available.

Definition at line 1859 of file cluster.c.

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Variable Documentation

fr_redis_cluster_rcodes_table

fr_table_num_sorted_t const fr_redis_cluster_rcodes_table[]

Initial value:

= {
        { L("bad-input"),       FR_REDIS_CLUSTER_RCODE_BAD_INPUT        },
        { L("failed"),          FR_REDIS_CLUSTER_RCODE_FAILED           },
        { L("ignored"),         FR_REDIS_CLUSTER_RCODE_IGNORED          },
        { L("no-connection"),   FR_REDIS_CLUSTER_RCODE_NO_CONNECTION    },
        { L("success"),         FR_REDIS_CLUSTER_RCODE_SUCCESS          }
}

Definition at line 277 of file cluster.c.

fr_redis_cluster_rcodes_table_len

size_t fr_redis_cluster_rcodes_table_len = NUM_ELEMENTS(fr_redis_cluster_rcodes_table)

Definition at line 284 of file cluster.c.