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Diffstat (limited to 'src/cluster.h')
| -rw-r--r-- | src/cluster.h | 447 |
1 files changed, 447 insertions, 0 deletions
diff --git a/src/cluster.h b/src/cluster.h new file mode 100644 index 0000000..db05ebc --- /dev/null +++ b/src/cluster.h @@ -0,0 +1,447 @@ +#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 */ + list *send_msg_queue; /* List of messages to be sent */ + size_t head_msg_send_offset; /* Number of bytes already sent of message at head of queue */ + unsigned long long send_msg_queue_mem; /* Memory in bytes used by message queue */ + 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 (10) /* 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 */ + char shard_id[CLUSTER_NAMELEN]; /* shard id, 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. */ + unsigned long long last_in_ping_gossip; /* The number of the last carried in the ping gossip section */ + 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 */ + sds human_nodename; /* The known human readable nodename for this node */ + int tcp_port; /* Latest known clients TCP port. */ + int tls_port; /* Latest known clients TLS port */ + 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 { + redisDb *db; /* A link back to the db this dict belongs to */ +} clusterDictMetadata; + +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 *shards; /* Hash table of shard_id -> list (of nodes) 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 */ + + /* Bit map for slots that are no longer claimed by the owner in cluster PING + * messages. During slot migration, the owner will stop claiming the slot after + * the ownership transfer. Set the bit corresponding to the slot when a node + * stops claiming the slot. This prevents spreading incorrect information (that + * source still owns the slot) using UPDATE messages. */ + unsigned char owner_not_claiming_slot[CLUSTER_SLOTS / 8]; +} 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; /* primary 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; /* secondary port last time it was seen */ + 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, + CLUSTERMSG_EXT_TYPE_HUMAN_NODENAME, + CLUSTERMSG_EXT_TYPE_FORGOTTEN_NODE, + CLUSTERMSG_EXT_TYPE_SHARDID, +} 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 { + char human_nodename[1]; /* The announced nodename, ends with \0. */ +} clusterMsgPingExtHumanNodename; + +typedef struct { + char name[CLUSTER_NAMELEN]; /* Node name. */ + uint64_t ttl; /* Remaining time to blacklist the node, in seconds. */ +} clusterMsgPingExtForgottenNode; + +static_assert(sizeof(clusterMsgPingExtForgottenNode) % 8 == 0, ""); + +typedef struct { + char shard_id[CLUSTER_NAMELEN]; /* The shard_id, 40 bytes fixed. */ +} clusterMsgPingExtShardId; + +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; + clusterMsgPingExtHumanNodename human_nodename; + clusterMsgPingExtForgottenNode forgotten_node; + clusterMsgPingExtShardId shard_id; + } 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; /* Primary port number (TCP or TLS). */ + 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; /* Secondary port number: if primary port is TCP port, this is + TLS port, and if primary port is TLS port, this is TCP port.*/ + 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 clusterInitListeners(void); +void clusterCron(void); +void clusterBeforeSleep(void); +clusterNode *clusterNodeGetMaster(clusterNode *node); +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(dict *d, dictEntry *entry); +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); +void clusterUpdateMyselfAnnouncedPorts(void); +sds clusterGenNodesDescription(client *c, int filter, int tls_primary); +sds genClusterInfoString(void); +void freeClusterLink(clusterLink *link); +void clusterUpdateMyselfHumanNodename(void); +int isValidAuxString(char *s, unsigned int length); +int getNodeDefaultClientPort(clusterNode *n); + +#endif /* __CLUSTER_H */ |