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cluster.c
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/* Redis Cluster implementation.
*
* Copyright (c) 2009-2012, Salvatore Sanfilippo <antirez at gmail dot com>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of Redis nor the names of its contributors may be used
* to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include "redis.h"
#include "cluster.h"
#include "endianconv.h"
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/socket.h>
clusterNode *createClusterNode(char *nodename, int flags);
int clusterAddNode(clusterNode *node);
void clusterAcceptHandler(aeEventLoop *el, int fd, void *privdata, int mask);
void clusterReadHandler(aeEventLoop *el, int fd, void *privdata, int mask);
void clusterSendPing(clusterLink *link, int type);
void clusterSendFail(char *nodename);
void clusterSendFailoverAuthIfNeeded(clusterNode *node, clusterMsg *request);
void clusterUpdateState(void);
int clusterNodeGetSlotBit(clusterNode *n, int slot);
sds clusterGenNodesDescription(int filter);
clusterNode *clusterLookupNode(char *name);
int clusterNodeAddSlave(clusterNode *master, clusterNode *slave);
int clusterAddSlot(clusterNode *n, int slot);
int clusterDelSlot(int slot);
int clusterDelNodeSlots(clusterNode *node);
int clusterNodeSetSlotBit(clusterNode *n, int slot);
void clusterSetMaster(clusterNode *n);
void clusterHandleSlaveFailover(void);
int bitmapTestBit(unsigned char *bitmap, int pos);
void clusterDoBeforeSleep(int flags);
/* -----------------------------------------------------------------------------
* Initialization
* -------------------------------------------------------------------------- */
/* This function is called at startup in order to set the currentEpoch
* (which is not saved on permanent storage) to the greatest configEpoch found
* in the loaded nodes (configEpoch is stored on permanent storage as soon as
* it changes for some node). */
void clusterSetStartupEpoch() {
dictIterator *di;
dictEntry *de;
di = dictGetSafeIterator(server.cluster->nodes);
while((de = dictNext(di)) != NULL) {
clusterNode *node = dictGetVal(de);
if (node->configEpoch > server.cluster->currentEpoch)
server.cluster->currentEpoch = node->configEpoch;
}
dictReleaseIterator(di);
}
int clusterLoadConfig(char *filename) {
FILE *fp = fopen(filename,"r");
char *line;
int maxline, j;
if (fp == NULL) return REDIS_ERR;
/* Parse the file. Note that single liens of the cluster config file can
* be really long as they include all the hash slots of the node.
* This means in the worst possible case, half of the Redis slots will be
* present in a single line, possibly in importing or migrating state, so
* together with the node ID of the sender/receiver.
*
* To simplify we allocate 1024+REDIS_CLUSTER_SLOTS*128 bytes per line. */
maxline = 1024+REDIS_CLUSTER_SLOTS*128;
line = zmalloc(maxline);
while(fgets(line,maxline,fp) != NULL) {
int argc;
sds *argv = sdssplitargs(line,&argc);
if (argv == NULL) goto fmterr;
clusterNode *n, *master;
char *p, *s;
/* Create this node if it does not exist */
n = clusterLookupNode(argv[0]);
if (!n) {
n = createClusterNode(argv[0],0);
clusterAddNode(n);
}
/* Address and port */
if ((p = strchr(argv[1],':')) == NULL) goto fmterr;
*p = '\0';
memcpy(n->ip,argv[1],strlen(argv[1])+1);
n->port = atoi(p+1);
/* Parse flags */
p = s = argv[2];
while(p) {
p = strchr(s,',');
if (p) *p = '\0';
if (!strcasecmp(s,"myself")) {
redisAssert(server.cluster->myself == NULL);
server.cluster->myself = n;
n->flags |= REDIS_NODE_MYSELF;
} else if (!strcasecmp(s,"master")) {
n->flags |= REDIS_NODE_MASTER;
} else if (!strcasecmp(s,"slave")) {
n->flags |= REDIS_NODE_SLAVE;
} else if (!strcasecmp(s,"fail?")) {
n->flags |= REDIS_NODE_PFAIL;
} else if (!strcasecmp(s,"fail")) {
n->flags |= REDIS_NODE_FAIL;
n->fail_time = mstime();
} else if (!strcasecmp(s,"handshake")) {
n->flags |= REDIS_NODE_HANDSHAKE;
} else if (!strcasecmp(s,"noaddr")) {
n->flags |= REDIS_NODE_NOADDR;
} else if (!strcasecmp(s,"noflags")) {
/* nothing to do */
} else {
redisPanic("Unknown flag in redis cluster config file");
}
if (p) s = p+1;
}
/* Get master if any. Set the master and populate master's
* slave list. */
if (argv[3][0] != '-') {
master = clusterLookupNode(argv[3]);
if (!master) {
master = createClusterNode(argv[3],0);
clusterAddNode(master);
}
n->slaveof = master;
clusterNodeAddSlave(master,n);
}
/* Set ping sent / pong received timestamps */
if (atoi(argv[4])) n->ping_sent = mstime();
if (atoi(argv[5])) n->pong_received = mstime();
/* Set configEpoch for this node. */
n->configEpoch = strtoull(argv[6],NULL,10);
/* Populate hash slots served by this instance. */
for (j = 8; j < argc; j++) {
int start, stop;
if (argv[j][0] == '[') {
/* Here we handle migrating / importing slots */
int slot;
char direction;
clusterNode *cn;
p = strchr(argv[j],'-');
redisAssert(p != NULL);
*p = '\0';
direction = p[1]; /* Either '>' or '<' */
slot = atoi(argv[j]+1);
p += 3;
cn = clusterLookupNode(p);
if (!cn) {
cn = createClusterNode(p,0);
clusterAddNode(cn);
}
if (direction == '>') {
server.cluster->migrating_slots_to[slot] = cn;
} else {
server.cluster->importing_slots_from[slot] = cn;
}
continue;
} else if ((p = strchr(argv[j],'-')) != NULL) {
*p = '\0';
start = atoi(argv[j]);
stop = atoi(p+1);
} else {
start = stop = atoi(argv[j]);
}
while(start <= stop) clusterAddSlot(n, start++);
}
sdsfreesplitres(argv,argc);
}
zfree(line);
fclose(fp);
/* Config sanity check */
redisAssert(server.cluster->myself != NULL);
redisLog(REDIS_NOTICE,"Node configuration loaded, I'm %.40s",
server.cluster->myself->name);
clusterSetStartupEpoch();
clusterUpdateState();
return REDIS_OK;
fmterr:
redisLog(REDIS_WARNING,"Unrecoverable error: corrupted cluster config file.");
fclose(fp);
exit(1);
}
/* Cluster node configuration is exactly the same as CLUSTER NODES output.
*
* This function writes the node config and returns 0, on error -1
* is returned. */
int clusterSaveConfig(int do_fsync) {
sds ci = clusterGenNodesDescription(REDIS_NODE_HANDSHAKE);
int fd;
if ((fd = open(server.cluster_configfile,O_WRONLY|O_CREAT|O_TRUNC,0644))
== -1) goto err;
if (write(fd,ci,sdslen(ci)) != (ssize_t)sdslen(ci)) goto err;
if (do_fsync) fsync(fd);
close(fd);
sdsfree(ci);
return 0;
err:
sdsfree(ci);
return -1;
}
void clusterSaveConfigOrDie(int do_fsync) {
if (clusterSaveConfig(do_fsync) == -1) {
redisLog(REDIS_WARNING,"Fatal: can't update cluster config file.");
exit(1);
}
}
void clusterInit(void) {
int saveconf = 0;
server.cluster = zmalloc(sizeof(clusterState));
server.cluster->myself = NULL;
server.cluster->currentEpoch = 0;
server.cluster->state = REDIS_CLUSTER_FAIL;
server.cluster->size = 1;
server.cluster->nodes = dictCreate(&clusterNodesDictType,NULL);
server.cluster->failover_auth_time = 0;
server.cluster->failover_auth_count = 0;
server.cluster->failover_auth_epoch = 0;
server.cluster->last_vote_epoch = 0;
server.cluster->stats_bus_messages_sent = 0;
server.cluster->stats_bus_messages_received = 0;
memset(server.cluster->migrating_slots_to,0,
sizeof(server.cluster->migrating_slots_to));
memset(server.cluster->importing_slots_from,0,
sizeof(server.cluster->importing_slots_from));
memset(server.cluster->slots,0,
sizeof(server.cluster->slots));
if (clusterLoadConfig(server.cluster_configfile) == REDIS_ERR) {
/* No configuration found. We will just use the random name provided
* by the createClusterNode() function. */
server.cluster->myself =
createClusterNode(NULL,REDIS_NODE_MYSELF|REDIS_NODE_MASTER);
redisLog(REDIS_NOTICE,"No cluster configuration found, I'm %.40s",
server.cluster->myself->name);
clusterAddNode(server.cluster->myself);
saveconf = 1;
}
if (saveconf) clusterSaveConfigOrDie(1);
/* We need a listening TCP port for our cluster messaging needs. */
server.cfd_count = 0;
if (listenToPort(server.port+REDIS_CLUSTER_PORT_INCR,
server.cfd,&server.cfd_count) == REDIS_ERR)
{
exit(1);
} else {
int j;
for (j = 0; j < server.cfd_count; j++) {
if (aeCreateFileEvent(server.el, server.cfd[j], AE_READABLE,
clusterAcceptHandler, NULL) == AE_ERR)
redisPanic("Unrecoverable error creating Redis Cluster "
"file event.");
}
}
/* The slots -> keys map is a sorted set. Init it. */
server.cluster->slots_to_keys = zslCreate();
}
/* -----------------------------------------------------------------------------
* CLUSTER communication link
* -------------------------------------------------------------------------- */
clusterLink *createClusterLink(clusterNode *node) {
clusterLink *link = zmalloc(sizeof(*link));
link->ctime = mstime();
link->sndbuf = sdsempty();
link->rcvbuf = sdsempty();
link->node = node;
link->fd = -1;
return link;
}
/* Free a cluster link, but does not free the associated node of course.
* This function will just make sure that the original node associated
* with this link will have the 'link' field set to NULL. */
void freeClusterLink(clusterLink *link) {
if (link->fd != -1) {
aeDeleteFileEvent(server.el, link->fd, AE_WRITABLE);
aeDeleteFileEvent(server.el, link->fd, AE_READABLE);
}
sdsfree(link->sndbuf);
sdsfree(link->rcvbuf);
if (link->node)
link->node->link = NULL;
close(link->fd);
zfree(link);
}
void clusterAcceptHandler(aeEventLoop *el, int fd, void *privdata, int mask) {
int cport, cfd;
char cip[REDIS_IP_STR_LEN];
clusterLink *link;
REDIS_NOTUSED(el);
REDIS_NOTUSED(mask);
REDIS_NOTUSED(privdata);
cfd = anetTcpAccept(server.neterr, fd, cip, sizeof(cip), &cport);
if (cfd == AE_ERR) {
redisLog(REDIS_VERBOSE,"Accepting cluster node: %s", server.neterr);
return;
}
anetNonBlock(NULL,cfd);
anetEnableTcpNoDelay(NULL,cfd);
/* Use non-blocking I/O for cluster messages. */
/* IPV6: might want to wrap a v6 address in [] */
redisLog(REDIS_VERBOSE,"Accepted cluster node %s:%d", cip, cport);
/* We need to create a temporary node in order to read the incoming
* packet in a valid contest. This node will be released once we
* read the packet and reply. */
link = createClusterLink(NULL);
link->fd = cfd;
aeCreateFileEvent(server.el,cfd,AE_READABLE,clusterReadHandler,link);
}
/* -----------------------------------------------------------------------------
* Key space handling
* -------------------------------------------------------------------------- */
/* We have 16384 hash slots. The hash slot of a given key is obtained
* as the least significant 14 bits of the crc16 of the key. */
unsigned int keyHashSlot(char *key, int keylen) {
return crc16(key,keylen) & 0x3FFF;
}
/* -----------------------------------------------------------------------------
* CLUSTER node API
* -------------------------------------------------------------------------- */
/* Create a new cluster node, with the specified flags.
* If "nodename" is NULL this is considered a first handshake and a random
* node name is assigned to this node (it will be fixed later when we'll
* receive the first pong).
*
* The node is created and returned to the user, but it is not automatically
* added to the nodes hash table. */
clusterNode *createClusterNode(char *nodename, int flags) {
clusterNode *node = zmalloc(sizeof(*node));
if (nodename)
memcpy(node->name, nodename, REDIS_CLUSTER_NAMELEN);
else
getRandomHexChars(node->name, REDIS_CLUSTER_NAMELEN);
node->ctime = mstime();
node->configEpoch = 0;
node->flags = flags;
memset(node->slots,0,sizeof(node->slots));
node->numslots = 0;
node->numslaves = 0;
node->slaves = NULL;
node->slaveof = NULL;
node->ping_sent = node->pong_received = 0;
node->fail_time = 0;
node->link = NULL;
memset(node->ip,0,sizeof(node->ip));
node->port = 0;
node->fail_reports = listCreate();
node->voted_time = 0;
listSetFreeMethod(node->fail_reports,zfree);
return node;
}
/* This function is called every time we get a failure report from a node.
* The side effect is to populate the fail_reports list (or to update
* the timestamp of an existing report).
*
* 'failing' is the node that is in failure state according to the
* 'sender' node.
*
* The function returns 0 if it just updates a timestamp of an existing
* failure report from the same sender. 1 is returned if a new failure
* report is created. */
int clusterNodeAddFailureReport(clusterNode *failing, clusterNode *sender) {
list *l = failing->fail_reports;
listNode *ln;
listIter li;
clusterNodeFailReport *fr;
/* If a failure report from the same sender already exists, just update
* the timestamp. */
listRewind(l,&li);
while ((ln = listNext(&li)) != NULL) {
fr = ln->value;
if (fr->node == sender) {
fr->time = mstime();
return 0;
}
}
/* Otherwise create a new report. */
fr = zmalloc(sizeof(*fr));
fr->node = sender;
fr->time = mstime();
listAddNodeTail(l,fr);
return 1;
}
/* Remove failure reports that are too old, where too old means reasonably
* older than the global node timeout. Note that anyway for a node to be
* flagged as FAIL we need to have a local PFAIL state that is at least
* older than the global node timeout, so we don't just trust the number
* of failure reports from other nodes. */
void clusterNodeCleanupFailureReports(clusterNode *node) {
list *l = node->fail_reports;
listNode *ln;
listIter li;
clusterNodeFailReport *fr;
mstime_t maxtime = server.cluster_node_timeout *
REDIS_CLUSTER_FAIL_REPORT_VALIDITY_MULT;
mstime_t now = mstime();
listRewind(l,&li);
while ((ln = listNext(&li)) != NULL) {
fr = ln->value;
if (now - fr->time > maxtime) listDelNode(l,ln);
}
}
/* Remove the failing report for 'node' if it was previously considered
* failing by 'sender'. This function is called when a node informs us via
* gossip that a node is OK from its point of view (no FAIL or PFAIL flags).
*
* Note that this function is called relatively often as it gets called even
* when there are no nodes failing, and is O(N), however when the cluster is
* fine the failure reports list is empty so the function runs in constant
* time.
*
* The function returns 1 if the failure report was found and removed.
* Otherwise 0 is returned. */
int clusterNodeDelFailureReport(clusterNode *node, clusterNode *sender) {
list *l = node->fail_reports;
listNode *ln;
listIter li;
clusterNodeFailReport *fr;
/* Search for a failure report from this sender. */
listRewind(l,&li);
while ((ln = listNext(&li)) != NULL) {
fr = ln->value;
if (fr->node == sender) break;
}
if (!ln) return 0; /* No failure report from this sender. */
/* Remove the failure report. */
listDelNode(l,ln);
clusterNodeCleanupFailureReports(node);
return 1;
}
/* Return the number of external nodes that believe 'node' is failing,
* not including this node, that may have a PFAIL or FAIL state for this
* node as well. */
int clusterNodeFailureReportsCount(clusterNode *node) {
clusterNodeCleanupFailureReports(node);
return listLength(node->fail_reports);
}
int clusterNodeRemoveSlave(clusterNode *master, clusterNode *slave) {
int j;
for (j = 0; j < master->numslaves; j++) {
if (master->slaves[j] == slave) {
memmove(master->slaves+j,master->slaves+(j+1),
(master->numslaves-1)-j);
master->numslaves--;
return REDIS_OK;
}
}
return REDIS_ERR;
}
int clusterNodeAddSlave(clusterNode *master, clusterNode *slave) {
int j;
/* If it's already a slave, don't add it again. */
for (j = 0; j < master->numslaves; j++)
if (master->slaves[j] == slave) return REDIS_ERR;
master->slaves = zrealloc(master->slaves,
sizeof(clusterNode*)*(master->numslaves+1));
master->slaves[master->numslaves] = slave;
master->numslaves++;
return REDIS_OK;
}
void clusterNodeResetSlaves(clusterNode *n) {
zfree(n->slaves);
n->numslaves = 0;
}
void freeClusterNode(clusterNode *n) {
sds nodename;
nodename = sdsnewlen(n->name, REDIS_CLUSTER_NAMELEN);
redisAssert(dictDelete(server.cluster->nodes,nodename) == DICT_OK);
sdsfree(nodename);
if (n->slaveof) clusterNodeRemoveSlave(n->slaveof, n);
if (n->link) freeClusterLink(n->link);
listRelease(n->fail_reports);
zfree(n);
}
/* Add a node to the nodes hash table */
int clusterAddNode(clusterNode *node) {
int retval;
retval = dictAdd(server.cluster->nodes,
sdsnewlen(node->name,REDIS_CLUSTER_NAMELEN), node);
return (retval == DICT_OK) ? REDIS_OK : REDIS_ERR;
}
/* Remove a node from the cluster:
* 1) Mark all the nodes handled by it as unassigned.
* 2) Remove all the failure reports sent by this node.
* 3) Free the node, that will in turn remove it from the hash table
* and from the list of slaves of its master, if it is a slave node.
*/
void clusterDelNode(clusterNode *delnode) {
int j;
dictIterator *di;
dictEntry *de;
/* 1) Mark slots as unassigned. */
for (j = 0; j < REDIS_CLUSTER_SLOTS; j++) {
if (server.cluster->importing_slots_from[j] == delnode)
server.cluster->importing_slots_from[j] = NULL;
if (server.cluster->migrating_slots_to[j] == delnode)
server.cluster->migrating_slots_to[j] = NULL;
if (server.cluster->slots[j] == delnode)
clusterDelSlot(j);
}
/* 2) Remove failure reports. */
di = dictGetSafeIterator(server.cluster->nodes);
while((de = dictNext(di)) != NULL) {
clusterNode *node = dictGetVal(de);
if (node == delnode) continue;
clusterNodeDelFailureReport(node,delnode);
}
dictReleaseIterator(di);
/* 3) Free the node, unlinking it from the cluster. */
freeClusterNode(delnode);
}
/* Node lookup by name */
clusterNode *clusterLookupNode(char *name) {
sds s = sdsnewlen(name, REDIS_CLUSTER_NAMELEN);
struct dictEntry *de;
de = dictFind(server.cluster->nodes,s);
sdsfree(s);
if (de == NULL) return NULL;
return dictGetVal(de);
}
/* This is only used after the handshake. When we connect a given IP/PORT
* as a result of CLUSTER MEET we don't have the node name yet, so we
* pick a random one, and will fix it when we receive the PONG request using
* this function. */
void clusterRenameNode(clusterNode *node, char *newname) {
int retval;
sds s = sdsnewlen(node->name, REDIS_CLUSTER_NAMELEN);
redisLog(REDIS_DEBUG,"Renaming node %.40s into %.40s",
node->name, newname);
retval = dictDelete(server.cluster->nodes, s);
sdsfree(s);
redisAssert(retval == DICT_OK);
memcpy(node->name, newname, REDIS_CLUSTER_NAMELEN);
clusterAddNode(node);
}
/* -----------------------------------------------------------------------------
* CLUSTER messages exchange - PING/PONG and gossip
* -------------------------------------------------------------------------- */
/* This function checks if a given node should be marked as FAIL.
* It happens if the following conditions are met:
*
* 1) We received enough failure reports from other master nodes via gossip.
* Enough means that the majority of the masters signaled the node is
* down recently.
* 2) We believe this node is in PFAIL state.
*
* If a failure is detected we also inform the whole cluster about this
* event trying to force every other node to set the FAIL flag for the node.
*
* Note that the form of agreement used here is weak, as we collect the majority
* of masters state during some time, and even if we force agreement by
* propagating the FAIL message, because of partitions we may not reach every
* node. However:
*
* 1) Either we reach the majority and eventually the FAIL state will propagate
* to all the cluster.
* 2) Or there is no majority so no slave promotion will be authorized and the
* FAIL flag will be cleared after some time.
*/
void markNodeAsFailingIfNeeded(clusterNode *node) {
int failures;
int needed_quorum = (server.cluster->size / 2) + 1;
if (!(node->flags & REDIS_NODE_PFAIL)) return; /* We can reach it. */
if (node->flags & REDIS_NODE_FAIL) return; /* Already FAILing. */
failures = clusterNodeFailureReportsCount(node);
/* Also count myself as a voter if I'm a master. */
if (server.cluster->myself->flags & REDIS_NODE_MASTER)
failures += 1;
if (failures < needed_quorum) return; /* No weak agreement from masters. */
redisLog(REDIS_NOTICE,
"Marking node %.40s as failing (quorum reached).", node->name);
/* Mark the node as failing. */
node->flags &= ~REDIS_NODE_PFAIL;
node->flags |= REDIS_NODE_FAIL;
node->fail_time = mstime();
/* Broadcast the failing node name to everybody, forcing all the other
* reachable nodes to flag the node as FAIL. */
if (server.cluster->myself->flags & REDIS_NODE_MASTER)
clusterSendFail(node->name);
clusterDoBeforeSleep(CLUSTER_TODO_UPDATE_STATE|CLUSTER_TODO_SAVE_CONFIG);
}
/* This function is called only if a node is marked as FAIL, but we are able
* to reach it again. It checks if there are the conditions to undo the FAIL
* state. */
void clearNodeFailureIfNeeded(clusterNode *node) {
time_t now = mstime();
redisAssert(node->flags & REDIS_NODE_FAIL);
/* For slaves we always clear the FAIL flag if we can contact the
* node again. */
if (node->flags & REDIS_NODE_SLAVE) {
redisLog(REDIS_NOTICE,
"Clear FAIL state for node %.40s: slave is reachable again.",
node->name);
node->flags &= ~REDIS_NODE_FAIL;
clusterDoBeforeSleep(CLUSTER_TODO_UPDATE_STATE|CLUSTER_TODO_SAVE_CONFIG);
}
/* If it is a master and...
* 1) The FAIL state is old enough.
* 2) It is yet serving slots from our point of view (not failed over).
* Apparently no one is going to fix these slots, clear the FAIL flag. */
if (node->flags & REDIS_NODE_MASTER &&
node->numslots > 0 &&
(now - node->fail_time) >
(server.cluster_node_timeout * REDIS_CLUSTER_FAIL_UNDO_TIME_MULT))
{
redisLog(REDIS_NOTICE,
"Clear FAIL state for node %.40s: is reachable again and nobody is serving its slots after some time.",
node->name);
node->flags &= ~REDIS_NODE_FAIL;
clusterDoBeforeSleep(CLUSTER_TODO_UPDATE_STATE|CLUSTER_TODO_SAVE_CONFIG);
}
}
/* Return true if we already have a node in HANDSHAKE state matching the
* specified ip address and port number. This function is used in order to
* avoid adding a new handshake node for the same address multiple times. */
int clusterHandshakeInProgress(char *ip, int port) {
dictIterator *di;
dictEntry *de;
di = dictGetSafeIterator(server.cluster->nodes);
while((de = dictNext(di)) != NULL) {
clusterNode *node = dictGetVal(de);
if (!(node->flags & REDIS_NODE_HANDSHAKE)) continue;
if (!strcasecmp(node->ip,ip) && node->port == port) break;
}
dictReleaseIterator(di);
return de != NULL;
}
/* Process the gossip section of PING or PONG packets.
* Note that this function assumes that the packet is already sanity-checked
* by the caller, not in the content of the gossip section, but in the
* length. */
void clusterProcessGossipSection(clusterMsg *hdr, clusterLink *link) {
uint16_t count = ntohs(hdr->count);
clusterMsgDataGossip *g = (clusterMsgDataGossip*) hdr->data.ping.gossip;
clusterNode *sender = link->node ? link->node : clusterLookupNode(hdr->sender);
while(count--) {
sds ci = sdsempty();
uint16_t flags = ntohs(g->flags);
clusterNode *node;
if (flags == 0) ci = sdscat(ci,"noflags,");
if (flags & REDIS_NODE_MYSELF) ci = sdscat(ci,"myself,");
if (flags & REDIS_NODE_MASTER) ci = sdscat(ci,"master,");
if (flags & REDIS_NODE_SLAVE) ci = sdscat(ci,"slave,");
if (flags & REDIS_NODE_PFAIL) ci = sdscat(ci,"fail?,");
if (flags & REDIS_NODE_FAIL) ci = sdscat(ci,"fail,");
if (flags & REDIS_NODE_HANDSHAKE) ci = sdscat(ci,"handshake,");
if (flags & REDIS_NODE_NOADDR) ci = sdscat(ci,"noaddr,");
if (ci[sdslen(ci)-1] == ',') ci[sdslen(ci)-1] = ' ';
redisLog(REDIS_DEBUG,"GOSSIP %.40s %s:%d %s",
g->nodename,
g->ip,
ntohs(g->port),
ci);
sdsfree(ci);
/* Update our state accordingly to the gossip sections */
node = clusterLookupNode(g->nodename);
if (node != NULL) {
/* We already know this node.
Handle failure reports, only when the sender is a master. */
if (sender && sender->flags & REDIS_NODE_MASTER &&
node != server.cluster->myself)
{
if (flags & (REDIS_NODE_FAIL|REDIS_NODE_PFAIL)) {
if (clusterNodeAddFailureReport(node,sender)) {
redisLog(REDIS_NOTICE,
"Node %.40s reported node %.40s as not reachable.",
sender->name, node->name);
}
markNodeAsFailingIfNeeded(node);
} else {
if (clusterNodeDelFailureReport(node,sender)) {
redisLog(REDIS_NOTICE,
"Node %.40s reported node %.40s is back online.",
sender->name, node->name);
}
}
}
} else {
/* If it's not in NOADDR state and we don't have it, we
* start an handshake process against this IP/PORT pairs.
*
* Note that we require that the sender of this gossip message
* is a well known node in our cluster, otherwise we risk
* joining another cluster. */
if (sender && !(flags & REDIS_NODE_NOADDR) &&
!clusterHandshakeInProgress(g->ip,ntohs(g->port)))
{
clusterNode *newnode;
redisLog(REDIS_DEBUG,"Adding the new node");
newnode = createClusterNode(NULL,REDIS_NODE_HANDSHAKE);
memcpy(newnode->ip,g->ip,sizeof(g->ip));
newnode->port = ntohs(g->port);
clusterAddNode(newnode);
}
}
/* Next node */
g++;
}
}
/* IP -> string conversion. 'buf' is supposed to at least be 46 bytes. */
void nodeIp2String(char *buf, clusterLink *link) {
struct sockaddr_storage sa;
socklen_t salen = sizeof(sa);
if (getpeername(link->fd, (struct sockaddr*) &sa, &salen) == -1)
redisPanic("getpeername() failed.");
if (sa.ss_family == AF_INET) {
struct sockaddr_in *s = (struct sockaddr_in *)&sa;
inet_ntop(AF_INET,(void*)&(s->sin_addr),buf,REDIS_CLUSTER_IPLEN);
} else {
struct sockaddr_in6 *s = (struct sockaddr_in6 *)&sa;
inet_ntop(AF_INET6,(void*)&(s->sin6_addr),buf,REDIS_CLUSTER_IPLEN);
}
}
/* Update the node address to the IP address that can be extracted
* from link->fd, and at the specified port.
* Also disconnect the node link so that we'll connect again to the new
* address.
*
* If the ip/port pair are already correct no operation is performed at
* all.
*
* The function returns 0 if the node address is still the same,
* otherwise 1 is returned. */
int nodeUpdateAddressIfNeeded(clusterNode *node, clusterLink *link, int port) {
char ip[REDIS_IP_STR_LEN];
/* We don't proceed if the link is the same as the sender link, as this
* function is designed to see if the node link is consistent with the
* symmetric link that is used to receive PINGs from the node.
*
* As a side effect this function never frees the passed 'link', so
* it is safe to call during packet processing. */
if (link == node->link) return 0;
nodeIp2String(ip,link);
if (node->port == port && strcmp(ip,node->ip) == 0) return 0;
/* IP / port is different, update it. */
memcpy(node->ip,ip,sizeof(ip));
node->port = port;
if (node->link) freeClusterLink(node->link);
redisLog(REDIS_WARNING,"Address updated for node %.40s, now %s:%d",
node->name, node->ip, node->port);
return 1;
}
/* When this function is called, there is a packet to process starting
* at node->rcvbuf. Releasing the buffer is up to the caller, so this
* function should just handle the higher level stuff of processing the
* packet, modifying the cluster state if needed.
*
* The function returns 1 if the link is still valid after the packet
* was processed, otherwise 0 if the link was freed since the packet
* processing lead to some inconsistency error (for instance a PONG
* received from the wrong sender ID). */
int clusterProcessPacket(clusterLink *link) {
clusterMsg *hdr = (clusterMsg*) link->rcvbuf;
uint32_t totlen = ntohl(hdr->totlen);
uint16_t type = ntohs(hdr->type);
uint16_t flags = ntohs(hdr->flags);
uint64_t senderCurrentEpoch, senderConfigEpoch;
clusterNode *sender;
server.cluster->stats_bus_messages_received++;
redisLog(REDIS_DEBUG,"--- Processing packet of type %d, %lu bytes",
type, (unsigned long) totlen);
/* Perform sanity checks */
if (totlen < 8) return 1;
if (totlen > sdslen(link->rcvbuf)) return 1;
if (type == CLUSTERMSG_TYPE_PING || type == CLUSTERMSG_TYPE_PONG ||
type == CLUSTERMSG_TYPE_MEET)
{
uint16_t count = ntohs(hdr->count);
uint32_t explen; /* expected length of this packet */
explen = sizeof(clusterMsg)-sizeof(union clusterMsgData);
explen += (sizeof(clusterMsgDataGossip)*count);
if (totlen != explen) return 1;
} else if (type == CLUSTERMSG_TYPE_FAIL) {
uint32_t explen = sizeof(clusterMsg)-sizeof(union clusterMsgData);
explen += sizeof(clusterMsgDataFail);
if (totlen != explen) return 1;
} else if (type == CLUSTERMSG_TYPE_PUBLISH) {
uint32_t explen = sizeof(clusterMsg)-sizeof(union clusterMsgData);
explen += sizeof(clusterMsgDataPublish) +
ntohl(hdr->data.publish.msg.channel_len) +
ntohl(hdr->data.publish.msg.message_len);
if (totlen != explen) return 1;
} else if (type == CLUSTERMSG_TYPE_FAILOVER_AUTH_REQUEST ||
type == CLUSTERMSG_TYPE_FAILOVER_AUTH_ACK) {
uint32_t explen = sizeof(clusterMsg)-sizeof(union clusterMsgData);
if (totlen != explen) return 1;
}
/* Check if the sender is a known node. */
sender = clusterLookupNode(hdr->sender);
if (sender && !(sender->flags & REDIS_NODE_HANDSHAKE)) {
/* Update our curretEpoch if we see a newer epoch in the cluster. */
senderCurrentEpoch = ntohu64(hdr->currentEpoch);
senderConfigEpoch = ntohu64(hdr->configEpoch);
if (senderCurrentEpoch > server.cluster->currentEpoch)
server.cluster->currentEpoch = senderCurrentEpoch;
/* Update the sender configEpoch if it is publishing a newer one. */
if (senderConfigEpoch > sender->configEpoch) {
sender->configEpoch = senderConfigEpoch;
clusterDoBeforeSleep(CLUSTER_TODO_SAVE_CONFIG|CLUSTER_TODO_FSYNC_CONFIG);
}
}
/* Process packets by type. */
if (type == CLUSTERMSG_TYPE_PING || type == CLUSTERMSG_TYPE_MEET) {
redisLog(REDIS_DEBUG,"Ping packet received: %p", (void*)link->node);
/* Add this node if it is new for us and the msg type is MEET.
* In this stage we don't try to add the node with the right
* flags, slaveof pointer, and so forth, as this details will be
* resolved when we'll receive PONGs from the node. */
if (!sender && type == CLUSTERMSG_TYPE_MEET) {
clusterNode *node;
node = createClusterNode(NULL,REDIS_NODE_HANDSHAKE);
nodeIp2String(node->ip,link);
node->port = ntohs(hdr->port);
clusterAddNode(node);
clusterDoBeforeSleep(CLUSTER_TODO_SAVE_CONFIG);
}
/* Get info from the gossip section */
clusterProcessGossipSection(hdr,link);
/* Anyway reply with a PONG */
clusterSendPing(link,CLUSTERMSG_TYPE_PONG);
}
/* PING or PONG: process config information. */
if (type == CLUSTERMSG_TYPE_PING || type == CLUSTERMSG_TYPE_PONG ||
type == CLUSTERMSG_TYPE_MEET)
{
redisLog(REDIS_DEBUG,"%s packet received: %p",
type == CLUSTERMSG_TYPE_PING ? "ping" : "pong",
(void*)link->node);
if (link->node) {
if (link->node->flags & REDIS_NODE_HANDSHAKE) {
/* If we already have this node, try to change the
* IP/port of the node with the new one. */
if (sender) {
redisLog(REDIS_WARNING,
"Handshake error: we already know node %.40s, updating the address if needed.", sender->name);
if (nodeUpdateAddressIfNeeded(sender,link,ntohs(hdr->port)))
{
clusterDoBeforeSleep(CLUSTER_TODO_SAVE_CONFIG|
CLUSTER_TODO_UPDATE_STATE);
}
/* Free this node as we alrady have it. This will
* cause the link to be freed as well. */
freeClusterNode(link->node);
return 0;
}
/* First thing to do is replacing the random name with the
* right node name if this was an handshake stage. */
clusterRenameNode(link->node, hdr->sender);
redisLog(REDIS_DEBUG,"Handshake with node %.40s completed.",
link->node->name);
link->node->flags &= ~REDIS_NODE_HANDSHAKE;
link->node->flags |= flags&(REDIS_NODE_MASTER|REDIS_NODE_SLAVE);
clusterDoBeforeSleep(CLUSTER_TODO_SAVE_CONFIG);
} else if (memcmp(link->node->name,hdr->sender,
REDIS_CLUSTER_NAMELEN) != 0)
{
/* If the reply has a non matching node ID we
* disconnect this node and set it as not having an associated
* address. */
redisLog(REDIS_DEBUG,"PONG contains mismatching sender ID");
link->node->flags |= REDIS_NODE_NOADDR;
link->node->ip[0] = '\0';
link->node->port = 0;
freeClusterLink(link);
clusterDoBeforeSleep(CLUSTER_TODO_SAVE_CONFIG);
/* FIXME: remove this node if we already have it.
*
* If we already have it but the IP is different, use
* the new one if the old node is in FAIL, PFAIL, or NOADDR
* status... */
return 0;