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redis/src/cluster.h

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#ifndef __CLUSTER_H
#define __CLUSTER_H
/*-----------------------------------------------------------------------------
* Redis cluster data structures, defines, exported API.
*----------------------------------------------------------------------------*/
#define CLUSTER_SLOTS 16384
#define CLUSTER_OK 0 /* Everything looks ok */
#define CLUSTER_FAIL 1 /* The cluster can't work */
#define CLUSTER_NAMELEN 40 /* sha1 hex length */
#define CLUSTER_PORT_INCR 10000 /* Cluster port = baseport + PORT_INCR */
/* The following defines are amount of time, sometimes expressed as
* multiplicators of the node timeout value (when ending with MULT). */
#define CLUSTER_FAIL_REPORT_VALIDITY_MULT 2 /* Fail report validity. */
#define CLUSTER_FAIL_UNDO_TIME_MULT 2 /* Undo fail if master is back. */
#define CLUSTER_MF_TIMEOUT 5000 /* Milliseconds to do a manual failover. */
#define CLUSTER_MF_PAUSE_MULT 2 /* Master pause manual failover mult. */
#define CLUSTER_SLAVE_MIGRATION_DELAY 5000 /* Delay for slave migration. */
/* Redirection errors returned by getNodeByQuery(). */
#define CLUSTER_REDIR_NONE 0 /* Node can serve the request. */
#define CLUSTER_REDIR_CROSS_SLOT 1 /* -CROSSSLOT request. */
#define CLUSTER_REDIR_UNSTABLE 2 /* -TRYAGAIN redirection required */
#define CLUSTER_REDIR_ASK 3 /* -ASK redirection required. */
#define CLUSTER_REDIR_MOVED 4 /* -MOVED redirection required. */
#define CLUSTER_REDIR_DOWN_STATE 5 /* -CLUSTERDOWN, global state. */
#define CLUSTER_REDIR_DOWN_UNBOUND 6 /* -CLUSTERDOWN, unbound slot. */
#define CLUSTER_REDIR_DOWN_RO_STATE 7 /* -CLUSTERDOWN, allow reads. */
struct clusterNode;
/* clusterLink encapsulates everything needed to talk with a remote node. */
typedef struct clusterLink {
mstime_t ctime; /* Link creation time */
connection *conn; /* Connection to remote node */
sds sndbuf; /* Packet send buffer */
char *rcvbuf; /* Packet reception buffer */
size_t rcvbuf_len; /* Used size of rcvbuf */
size_t rcvbuf_alloc; /* Allocated size of rcvbuf */
struct clusterNode *node; /* Node related to this link. Initialized to NULL when unknown */
int inbound; /* 1 if this link is an inbound link accepted from the related node */
} clusterLink;
/* Cluster node flags and macros. */
#define CLUSTER_NODE_MASTER 1 /* The node is a master */
#define CLUSTER_NODE_SLAVE 2 /* The node is a slave */
#define CLUSTER_NODE_PFAIL 4 /* Failure? Need acknowledge */
#define CLUSTER_NODE_FAIL 8 /* The node is believed to be malfunctioning */
#define CLUSTER_NODE_MYSELF 16 /* This node is myself */
#define CLUSTER_NODE_HANDSHAKE 32 /* We have still to exchange the first ping */
#define CLUSTER_NODE_NOADDR 64 /* We don't know the address of this node */
#define CLUSTER_NODE_MEET 128 /* Send a MEET message to this node */
#define CLUSTER_NODE_MIGRATE_TO 256 /* Master eligible for replica migration. */
#define CLUSTER_NODE_NOFAILOVER 512 /* Slave will not try to failover. */
#define CLUSTER_NODE_NULL_NAME "\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000"
#define nodeIsMaster(n) ((n)->flags & CLUSTER_NODE_MASTER)
#define nodeIsSlave(n) ((n)->flags & CLUSTER_NODE_SLAVE)
#define nodeInHandshake(n) ((n)->flags & CLUSTER_NODE_HANDSHAKE)
#define nodeHasAddr(n) (!((n)->flags & CLUSTER_NODE_NOADDR))
#define nodeWithoutAddr(n) ((n)->flags & CLUSTER_NODE_NOADDR)
#define nodeTimedOut(n) ((n)->flags & CLUSTER_NODE_PFAIL)
#define nodeFailed(n) ((n)->flags & CLUSTER_NODE_FAIL)
#define nodeCantFailover(n) ((n)->flags & CLUSTER_NODE_NOFAILOVER)
/* Reasons why a slave is not able to failover. */
#define CLUSTER_CANT_FAILOVER_NONE 0
#define CLUSTER_CANT_FAILOVER_DATA_AGE 1
#define CLUSTER_CANT_FAILOVER_WAITING_DELAY 2
#define CLUSTER_CANT_FAILOVER_EXPIRED 3
#define CLUSTER_CANT_FAILOVER_WAITING_VOTES 4
#define CLUSTER_CANT_FAILOVER_RELOG_PERIOD (60*5) /* seconds. */
/* clusterState todo_before_sleep flags. */
#define CLUSTER_TODO_HANDLE_FAILOVER (1<<0)
#define CLUSTER_TODO_UPDATE_STATE (1<<1)
#define CLUSTER_TODO_SAVE_CONFIG (1<<2)
#define CLUSTER_TODO_FSYNC_CONFIG (1<<3)
#define CLUSTER_TODO_HANDLE_MANUALFAILOVER (1<<4)
/* Message types.
*
* Note that the PING, PONG and MEET messages are actually the same exact
* kind of packet. PONG is the reply to ping, in the exact format as a PING,
* while MEET is a special PING that forces the receiver to add the sender
* as a node (if it is not already in the list). */
#define CLUSTERMSG_TYPE_PING 0 /* Ping */
#define CLUSTERMSG_TYPE_PONG 1 /* Pong (reply to Ping) */
#define CLUSTERMSG_TYPE_MEET 2 /* Meet "let's join" message */
#define CLUSTERMSG_TYPE_FAIL 3 /* Mark node xxx as failing */
#define CLUSTERMSG_TYPE_PUBLISH 4 /* Pub/Sub Publish propagation */
#define CLUSTERMSG_TYPE_FAILOVER_AUTH_REQUEST 5 /* May I failover? */
#define CLUSTERMSG_TYPE_FAILOVER_AUTH_ACK 6 /* Yes, you have my vote */
#define CLUSTERMSG_TYPE_UPDATE 7 /* Another node slots configuration */
#define CLUSTERMSG_TYPE_MFSTART 8 /* Pause clients for manual failover */
#define CLUSTERMSG_TYPE_MODULE 9 /* Module cluster API message. */
#define CLUSTERMSG_TYPE_PUBLISHSHARD 10 /* Pub/Sub Publish shard propagation */
#define CLUSTERMSG_TYPE_COUNT 11 /* Total number of message types. */
/* Flags that a module can set in order to prevent certain Redis Cluster
* features to be enabled. Useful when implementing a different distributed
* system on top of Redis Cluster message bus, using modules. */
#define CLUSTER_MODULE_FLAG_NONE 0
#define CLUSTER_MODULE_FLAG_NO_FAILOVER (1<<1)
#define CLUSTER_MODULE_FLAG_NO_REDIRECTION (1<<2)
/* This structure represent elements of node->fail_reports. */
typedef struct clusterNodeFailReport {
struct clusterNode *node; /* Node reporting the failure condition. */
mstime_t time; /* Time of the last report from this node. */
} clusterNodeFailReport;
typedef struct clusterNode {
mstime_t ctime; /* Node object creation time. */
char name[CLUSTER_NAMELEN]; /* Node name, hex string, sha1-size */
int flags; /* CLUSTER_NODE_... */
uint64_t configEpoch; /* Last configEpoch observed for this node */
unsigned char slots[CLUSTER_SLOTS/8]; /* slots handled by this node */
uint16_t *slot_info_pairs; /* Slots info represented as (start/end) pair (consecutive index). */
int slot_info_pairs_count; /* Used number of slots in slot_info_pairs */
int numslots; /* Number of slots handled by this node */
int numslaves; /* Number of slave nodes, if this is a master */
struct clusterNode **slaves; /* pointers to slave nodes */
struct clusterNode *slaveof; /* pointer to the master node. Note that it
may be NULL even if the node is a slave
if we don't have the master node in our
tables. */
mstime_t ping_sent; /* Unix time we sent latest ping */
mstime_t pong_received; /* Unix time we received the pong */
mstime_t data_received; /* Unix time we received any data */
mstime_t fail_time; /* Unix time when FAIL flag was set */
mstime_t voted_time; /* Last time we voted for a slave of this master */
mstime_t repl_offset_time; /* Unix time we received offset for this node */
mstime_t orphaned_time; /* Starting time of orphaned master condition */
long long repl_offset; /* Last known repl offset for this node. */
char ip[NET_IP_STR_LEN]; /* Latest known IP address of this node */
sds hostname; /* The known hostname for this node */
int port; /* Latest known clients port (TLS or plain). */
int pport; /* Latest known clients plaintext port. Only used
if the main clients port is for TLS. */
int cport; /* Latest known cluster port of this node. */
clusterLink *link; /* TCP/IP link established toward this node */
clusterLink *inbound_link; /* TCP/IP link accepted from this node */
list *fail_reports; /* List of nodes signaling this as failing */
} clusterNode;
/* Slot to keys for a single slot. The keys in the same slot are linked together
* using dictEntry metadata. */
typedef struct slotToKeys {
uint64_t count; /* Number of keys in the slot. */
dictEntry *head; /* The first key-value entry in the slot. */
} slotToKeys;
/* Slot to keys mapping for all slots, opaque outside this file. */
struct clusterSlotToKeyMapping {
slotToKeys by_slot[CLUSTER_SLOTS];
};
/* Dict entry metadata for cluster mode, used for the Slot to Key API to form a
* linked list of the entries belonging to the same slot. */
typedef struct clusterDictEntryMetadata {
dictEntry *prev; /* Prev entry with key in the same slot */
dictEntry *next; /* Next entry with key in the same slot */
} clusterDictEntryMetadata;
typedef struct clusterState {
clusterNode *myself; /* This node */
uint64_t currentEpoch;
int state; /* CLUSTER_OK, CLUSTER_FAIL, ... */
int size; /* Num of master nodes with at least one slot */
dict *nodes; /* Hash table of name -> clusterNode structures */
dict *nodes_black_list; /* Nodes we don't re-add for a few seconds. */
clusterNode *migrating_slots_to[CLUSTER_SLOTS];
clusterNode *importing_slots_from[CLUSTER_SLOTS];
clusterNode *slots[CLUSTER_SLOTS];
rax *slots_to_channels;
/* The following fields are used to take the slave state on elections. */
mstime_t failover_auth_time; /* Time of previous or next election. */
int failover_auth_count; /* Number of votes received so far. */
int failover_auth_sent; /* True if we already asked for votes. */
int failover_auth_rank; /* This slave rank for current auth request. */
uint64_t failover_auth_epoch; /* Epoch of the current election. */
int cant_failover_reason; /* Why a slave is currently not able to
failover. See the CANT_FAILOVER_* macros. */
/* Manual failover state in common. */
mstime_t mf_end; /* Manual failover time limit (ms unixtime).
It is zero if there is no MF in progress. */
/* Manual failover state of master. */
clusterNode *mf_slave; /* Slave performing the manual failover. */
/* Manual failover state of slave. */
long long mf_master_offset; /* Master offset the slave needs to start MF
or -1 if still not received. */
int mf_can_start; /* If non-zero signal that the manual failover
can start requesting masters vote. */
/* The following fields are used by masters to take state on elections. */
uint64_t lastVoteEpoch; /* Epoch of the last vote granted. */
int todo_before_sleep; /* Things to do in clusterBeforeSleep(). */
/* Stats */
/* Messages received and sent by type. */
long long stats_bus_messages_sent[CLUSTERMSG_TYPE_COUNT];
long long stats_bus_messages_received[CLUSTERMSG_TYPE_COUNT];
long long stats_pfail_nodes; /* Number of nodes in PFAIL status,
excluding nodes without address. */
unsigned long long stat_cluster_links_buffer_limit_exceeded; /* Total number of cluster links freed due to exceeding buffer limit */
} clusterState;
/* Redis cluster messages header */
/* Initially we don't know our "name", but we'll find it once we connect
* to the first node, using the getsockname() function. Then we'll use this
* address for all the next messages. */
typedef struct {
char nodename[CLUSTER_NAMELEN];
uint32_t ping_sent;
uint32_t pong_received;
char ip[NET_IP_STR_LEN]; /* IP address last time it was seen */
uint16_t port; /* base port last time it was seen */
uint16_t cport; /* cluster port last time it was seen */
uint16_t flags; /* node->flags copy */
uint16_t pport; /* plaintext-port, when base port is TLS */
uint16_t notused1;
} clusterMsgDataGossip;
typedef struct {
char nodename[CLUSTER_NAMELEN];
} clusterMsgDataFail;
typedef struct {
uint32_t channel_len;
uint32_t message_len;
unsigned char bulk_data[8]; /* 8 bytes just as placeholder. */
} clusterMsgDataPublish;
typedef struct {
uint64_t configEpoch; /* Config epoch of the specified instance. */
char nodename[CLUSTER_NAMELEN]; /* Name of the slots owner. */
unsigned char slots[CLUSTER_SLOTS/8]; /* Slots bitmap. */
} clusterMsgDataUpdate;
typedef struct {
uint64_t module_id; /* ID of the sender module. */
uint32_t len; /* ID of the sender module. */
uint8_t type; /* Type from 0 to 255. */
unsigned char bulk_data[3]; /* 3 bytes just as placeholder. */
} clusterMsgModule;
/* The cluster supports optional extension messages that can be sent
* along with ping/pong/meet messages to give additional info in a
* consistent manner. */
typedef enum {
CLUSTERMSG_EXT_TYPE_HOSTNAME,
} clusterMsgPingtypes;
/* Helper function for making sure extensions are eight byte aligned. */
#define EIGHT_BYTE_ALIGN(size) ((((size) + 7) / 8) * 8)
typedef struct {
char hostname[1]; /* The announced hostname, ends with \0. */
} clusterMsgPingExtHostname;
typedef struct {
uint32_t length; /* Total length of this extension message (including this header) */
uint16_t type; /* Type of this extension message (see clusterMsgPingExtTypes) */
uint16_t unused; /* 16 bits of padding to make this structure 8 byte aligned. */
union {
clusterMsgPingExtHostname hostname;
} ext[]; /* Actual extension information, formatted so that the data is 8
* byte aligned, regardless of its content. */
} clusterMsgPingExt;
union clusterMsgData {
/* PING, MEET and PONG */
struct {
/* Array of N clusterMsgDataGossip structures */
clusterMsgDataGossip gossip[1];
/* Extension data that can optionally be sent for ping/meet/pong
* messages. We can't explicitly define them here though, since
* the gossip array isn't the real length of the gossip data. */
} ping;
/* FAIL */
struct {
clusterMsgDataFail about;
} fail;
/* PUBLISH */
struct {
clusterMsgDataPublish msg;
} publish;
/* UPDATE */
struct {
clusterMsgDataUpdate nodecfg;
} update;
/* MODULE */
struct {
clusterMsgModule msg;
} module;
};
#define CLUSTER_PROTO_VER 1 /* Cluster bus protocol version. */
typedef struct {
char sig[4]; /* Signature "RCmb" (Redis Cluster message bus). */
uint32_t totlen; /* Total length of this message */
uint16_t ver; /* Protocol version, currently set to 1. */
uint16_t port; /* TCP base port number. */
uint16_t type; /* Message type */
uint16_t count; /* Only used for some kind of messages. */
uint64_t currentEpoch; /* The epoch accordingly to the sending node. */
uint64_t configEpoch; /* The config epoch if it's a master, or the last
epoch advertised by its master if it is a
slave. */
uint64_t offset; /* Master replication offset if node is a master or
processed replication offset if node is a slave. */
char sender[CLUSTER_NAMELEN]; /* Name of the sender node */
unsigned char myslots[CLUSTER_SLOTS/8];
char slaveof[CLUSTER_NAMELEN];
char myip[NET_IP_STR_LEN]; /* Sender IP, if not all zeroed. */
uint16_t extensions; /* Number of extensions sent along with this packet. */
char notused1[30]; /* 30 bytes reserved for future usage. */
uint16_t pport; /* Sender TCP plaintext port, if base port is TLS */
uint16_t cport; /* Sender TCP cluster bus port */
uint16_t flags; /* Sender node flags */
unsigned char state; /* Cluster state from the POV of the sender */
unsigned char mflags[3]; /* Message flags: CLUSTERMSG_FLAG[012]_... */
union clusterMsgData data;
} clusterMsg;
/* clusterMsg defines the gossip wire protocol exchanged among Redis cluster
* members, which can be running different versions of redis-server bits,
* especially during cluster rolling upgrades.
*
* Therefore, fields in this struct should remain at the same offset from
* release to release. The static asserts below ensures that incompatible
* changes in clusterMsg be caught at compile time.
*/
static_assert(offsetof(clusterMsg, sig) == 0, "unexpected field offset");
static_assert(offsetof(clusterMsg, totlen) == 4, "unexpected field offset");
static_assert(offsetof(clusterMsg, ver) == 8, "unexpected field offset");
static_assert(offsetof(clusterMsg, port) == 10, "unexpected field offset");
static_assert(offsetof(clusterMsg, type) == 12, "unexpected field offset");
static_assert(offsetof(clusterMsg, count) == 14, "unexpected field offset");
static_assert(offsetof(clusterMsg, currentEpoch) == 16, "unexpected field offset");
static_assert(offsetof(clusterMsg, configEpoch) == 24, "unexpected field offset");
static_assert(offsetof(clusterMsg, offset) == 32, "unexpected field offset");
static_assert(offsetof(clusterMsg, sender) == 40, "unexpected field offset");
static_assert(offsetof(clusterMsg, myslots) == 80, "unexpected field offset");
static_assert(offsetof(clusterMsg, slaveof) == 2128, "unexpected field offset");
static_assert(offsetof(clusterMsg, myip) == 2168, "unexpected field offset");
static_assert(offsetof(clusterMsg, extensions) == 2214, "unexpected field offset");
static_assert(offsetof(clusterMsg, notused1) == 2216, "unexpected field offset");
static_assert(offsetof(clusterMsg, pport) == 2246, "unexpected field offset");
static_assert(offsetof(clusterMsg, cport) == 2248, "unexpected field offset");
static_assert(offsetof(clusterMsg, flags) == 2250, "unexpected field offset");
static_assert(offsetof(clusterMsg, state) == 2252, "unexpected field offset");
static_assert(offsetof(clusterMsg, mflags) == 2253, "unexpected field offset");
static_assert(offsetof(clusterMsg, data) == 2256, "unexpected field offset");
#define CLUSTERMSG_MIN_LEN (sizeof(clusterMsg)-sizeof(union clusterMsgData))
/* Message flags better specify the packet content or are used to
* provide some information about the node state. */
#define CLUSTERMSG_FLAG0_PAUSED (1<<0) /* Master paused for manual failover. */
#define CLUSTERMSG_FLAG0_FORCEACK (1<<1) /* Give ACK to AUTH_REQUEST even if
master is up. */
#define CLUSTERMSG_FLAG0_EXT_DATA (1<<2) /* Message contains extension data */
/* ---------------------- API exported outside cluster.c -------------------- */
void clusterInit(void);
void clusterCron(void);
void clusterBeforeSleep(void);
clusterNode *getNodeByQuery(client *c, struct redisCommand *cmd, robj **argv, int argc, int *hashslot, int *ask);
int verifyClusterNodeId(const char *name, int length);
clusterNode *clusterLookupNode(const char *name, int length);
int clusterRedirectBlockedClientIfNeeded(client *c);
void clusterRedirectClient(client *c, clusterNode *n, int hashslot, int error_code);
void migrateCloseTimedoutSockets(void);
int verifyClusterConfigWithData(void);
unsigned long getClusterConnectionsCount(void);
int clusterSendModuleMessageToTarget(const char *target, uint64_t module_id, uint8_t type, const char *payload, uint32_t len);
void clusterPropagatePublish(robj *channel, robj *message, int sharded);
unsigned int keyHashSlot(char *key, int keylen);
void slotToKeyAddEntry(dictEntry *entry, redisDb *db);
void slotToKeyDelEntry(dictEntry *entry, redisDb *db);
void slotToKeyReplaceEntry(dictEntry *entry, redisDb *db);
void slotToKeyInit(redisDb *db);
void slotToKeyFlush(redisDb *db);
void slotToKeyDestroy(redisDb *db);
void clusterUpdateMyselfFlags(void);
void clusterUpdateMyselfIp(void);
void slotToChannelAdd(sds channel);
void slotToChannelDel(sds channel);
void clusterUpdateMyselfHostname(void);
#endif /* __CLUSTER_H */
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