diff --git a/script/wireshark-dissector.lua b/script/wireshark-dissector.lua index d45b7a5..c9d3ed8 100644 --- a/script/wireshark-dissector.lua +++ b/script/wireshark-dissector.lua @@ -1,68 +1,67 @@ -- dofile("wireshark-dissector.lua") -- do booth_proto = Proto("Booth","Booth") function T32(tree, buffer, start, format) local b = buffer(start, 4) return tree:add(b, string.format(format, b:uint())) end function booth_proto.dissector(buffer, pinfo, tree) local endbuf = buffer:len() pinfo.cols.protocol = "Booth" if (endbuf < 24) then pinfo.cols.info = "Booth - too small" else local hdr = tree:add(booth_proto, buffer(0, 24), "Booth header") local cmd = buffer(28, 4) local tcmd = T32(hdr, cmd, 0, "Cmd %08x, \"" .. cmd:string() .. "\""); local from = buffer(20, 4) local tfrom = T32(hdr, from, 0, "From %08x"); if bit.band(from:uint(), 0x80000000) > 0 then tfrom:add_expert_info(PI_PROTOCOL, PI_WARN, "Highest bit set") end local len = buffer(24, 4) local tlen = T32(hdr, len, 0, "Length %8d"); if len:uint() > 1000 then tlen:add_expert_info(PI_PROTOCOL, PI_WARN, "Length too big?") end T32(hdr, buffer, 32, "Result %08x"); T32(hdr, buffer, 12, "Magic %08x"); T32(hdr, buffer, 16, "Version %08x"); T32(hdr, buffer, 0, "IV %08x"); T32(hdr, buffer, 4, "Auth1 %08x"); T32(hdr, buffer, 8, "Auth2 %08x"); if (endbuf > 36) then local tick = tree:add(booth_proto, buffer(36, endbuf-36), "Booth data") local name = buffer(36, 64) tick:add(name, "Ticket name: ", name:string()) T32(tick, buffer, 36+64 + 0, "Leader: %08x") T32(tick, buffer, 36+64 + 4, "Term: %08x") T32(tick, buffer, 36+64 + 8, "Term valid for: %08x") - T32(tick, buffer, 36+64 + 12, "last Log index: %8d") - T32(tick, buffer, 36+64 + 16, "Leader commit: %8d") + T32(tick, buffer, 36+64 + 12, "Leader commit: %8d") end pinfo.cols.info = "Booth, cmd " .. cmd:string() end tree:add(booth_proto, buffer(0, endbuf), "data") end local tbl = DissectorTable.get("udp.port") tbl:add(9929, booth_proto) local tbl = DissectorTable.get("tcp.port") tbl:add(9929, booth_proto) end diff --git a/src/booth.h b/src/booth.h index 1a46b51..904066c 100644 --- a/src/booth.h +++ b/src/booth.h @@ -1,255 +1,250 @@ /* * Copyright (C) 2011 Jiaju Zhang * Copyright (C) 2013-2014 Philipp Marek * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This software is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #ifndef _BOOTH_H #define _BOOTH_H #include #include #include #include #include #define BOOTH_RUN_DIR "/var/run/booth/" #define BOOTH_LOG_DIR "/var/log" #define BOOTH_LOGFILE_NAME "booth.log" #define BOOTH_DEFAULT_CONF_DIR "/etc/booth/" #define BOOTH_DEFAULT_CONF_NAME "booth" #define BOOTH_DEFAULT_CONF_EXT ".conf" #define BOOTH_DEFAULT_CONF \ BOOTH_DEFAULT_CONF_DIR BOOTH_DEFAULT_CONF_NAME BOOTH_DEFAULT_CONF_EXT #define DAEMON_NAME "boothd" #define BOOTH_PATH_LEN 127 #define BOOTH_DEFAULT_PORT 9929 /* TODO: remove */ #define BOOTH_PROTO_FAMILY AF_INET #define BOOTHC_MAGIC 0x5F1BA08C #define BOOTHC_VERSION 0x00010002 /** Timeout value for poll(). * Determines frequency of periodic jobs, eg. when send-retries are done. * See process_tickets(). */ #define POLL_TIMEOUT 1000 /** @{ */ /** The on-network data structures and constants. */ #define BOOTH_NAME_LEN 64 #define CHAR2CONST(a,b,c,d) ((a << 24) | (b << 16) | (c << 8) | d) /* Says that the ticket shouldn't be active anywhere. * NONE wouldn't be specific enough. */ #define NO_ONE (-1) /* Says that another one should recover. */ #define TICKET_LOST CHAR2CONST('L', 'O', 'S', 'T') typedef unsigned char boothc_site [BOOTH_NAME_LEN]; typedef unsigned char boothc_ticket[BOOTH_NAME_LEN]; struct boothc_header { /** Authentication data; not used now. */ uint32_t iv; uint32_t auth1; uint32_t auth2; /** BOOTHC_MAGIC */ uint32_t magic; /** BOOTHC_VERSION */ uint32_t version; /** Packet source; site_id. See add_site(). */ uint32_t from; /** Length including header */ uint32_t length; /** The command respectively protocol state. See cmd_request_t. */ uint32_t cmd; /** Result of operation. 0 == OK */ uint32_t result; char data[0]; } __attribute__((packed)); struct ticket_msg { /** Ticket name. */ boothc_ticket id; /** Current leader. May be NO_ONE. See add_site(). * For a OP_REQ_VOTE this is */ uint32_t leader; /** Current term. */ uint32_t term; uint32_t term_valid_for; - union { - uint32_t prev_log_index; // TODO: NEEDED? - uint32_t last_log_index; // TODO: NEEDED? - /* No log index as such needed -- we only need to know the - * _current_ ticket owner. */ - uint32_t owner; - }; + /* Perhaps we need to send a status along, too - like + * starting, running, stopping, error, ...? */ uint32_t leader_commit; // TODO: NEEDED? } __attribute__((packed)); struct boothc_ticket_msg { struct boothc_header header; struct ticket_msg ticket; } __attribute__((packed)); typedef enum { /* 0x43 = "C"ommands */ CMD_LIST = CHAR2CONST('C', 'L', 's', 't'), CMD_GRANT = CHAR2CONST('C', 'G', 'n', 't'), CMD_REVOKE = CHAR2CONST('C', 'R', 'v', 'k'), /* Replies */ CMR_GENERAL = CHAR2CONST('G', 'n', 'l', 'R'), // Increase distance to CMR_GRANT CMR_LIST = CHAR2CONST('R', 'L', 's', 't'), CMR_GRANT = CHAR2CONST('R', 'G', 'n', 't'), CMR_REVOKE = CHAR2CONST('R', 'R', 'v', 'k'), /* Raft */ OP_REQ_VOTE = CHAR2CONST('R', 'V', 'o', 't'), OP_VOTE_FOR = CHAR2CONST('V', 't', 'F', 'r'), OP_HEARTBEAT= CHAR2CONST('H', 'r', 't', 'B'), /* AppendEntry in Raft */ OP_MY_INDEX = CHAR2CONST('M', 'I', 'd', 'x'), /* Answer to Heartbeat */ OP_REJECTED = CHAR2CONST('R', 'J', 'C', '!'), } cmd_request_t; /* TODO: make readable constants */ typedef enum { /* for compatibility with other functions */ RLT_SUCCESS = 0, RLT_ASYNC = CHAR2CONST('A', 's', 'y', 'n'), RLT_SYNC_SUCC = CHAR2CONST('S', 'c', 'c', 's'), RLT_SYNC_FAIL = CHAR2CONST('F', 'a', 'i', 'l'), RLT_INVALID_ARG = CHAR2CONST('I', 'A', 'r', 'g'), RLT_OVERGRANT = CHAR2CONST('O', 'v', 'e', 'r'), RLT_PROBABLY_SUCCESS = CHAR2CONST('S', 'u', 'c', '?'), RLT_BUSY = CHAR2CONST('B', 'u', 's', 'y'), RLT_TERM_OUTDATED = CHAR2CONST('T', 'O', 'd', 't'), RLT_TERM_STILL_VALID = CHAR2CONST('T', 'V', 'l', 'd'), } cmd_result_t; /** @} */ /** @{ */ struct booth_site { /** Calculated ID. See add_site(). */ int site_id; int type; int local; /** Roles, like ACCEPTOR, PROPOSER, or LEARNER. Not really used ATM. */ int role; char addr_string[BOOTH_NAME_LEN]; int tcp_fd; int udp_fd; /* 0-based, used for indexing into per-ticket weights */ int index; uint64_t bitmask; unsigned short family; union { struct sockaddr_in sa4; struct sockaddr_in6 sa6; }; int saddrlen; int addrlen; } __attribute__((packed)); extern struct booth_site *local; /** @} */ struct booth_transport; struct client { int fd; const struct booth_transport *transport; void (*workfn)(int); void (*deadfn)(int); }; extern struct client *clients; extern struct pollfd *pollfds; int client_add(int fd, const struct booth_transport *tpt, void (*workfn)(int ci), void (*deadfn)(int ci)); int do_read(int fd, void *buf, size_t count); int do_write(int fd, void *buf, size_t count); void process_connection(int ci); void safe_copy(char *dest, char *value, size_t buflen, const char *description); struct command_line { int type; /* ACT_ */ int op; /* OP_ */ char configfile[BOOTH_PATH_LEN]; char lockfile[BOOTH_PATH_LEN]; char site[BOOTH_NAME_LEN]; struct boothc_ticket_msg msg; }; extern struct command_line cl; /* http://gcc.gnu.org/onlinedocs/gcc/Typeof.html */ #define min(a__,b__) \ ({ typeof (a__) _a = (a__); \ typeof (b__) _b = (b__); \ _a < _b ? _a : _b; }) #define max(a__,b__) \ ({ typeof (a__) _a = (a__); \ typeof (b__) _b = (b__); \ _a > _b ? _a : _b; }) #endif /* _BOOTH_H */ diff --git a/src/inline-fn.h b/src/inline-fn.h index 2944e63..aea1394 100644 --- a/src/inline-fn.h +++ b/src/inline-fn.h @@ -1,305 +1,304 @@ /* * Copyright (C) 2013-2014 Philipp Marek * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This software is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #ifndef _INLINE_FN_H #define _INLINE_FN_H #include #include #include #include #include "config.h" #include "ticket.h" #include "transport.h" inline static uint32_t get_local_id(void) { return local ? local->site_id : -1; } inline static uint32_t get_node_id(struct booth_site *node) { return node ? node->site_id : NO_ONE; } inline static int term_valid_for(const struct ticket_config *tk) { int left; left = tk->term_expires - time(NULL); return (left < 0) ? 0 : left; } /** Returns number of seconds left, if any. */ inline static int leader_and_valid(const struct ticket_config *tk) { if (tk->leader != local) return 0; return term_valid_for(tk); } static inline void init_header_bare(struct boothc_header *h) { h->magic = htonl(BOOTHC_MAGIC); h->version = htonl(BOOTHC_VERSION); h->from = htonl(local->site_id); h->iv = htonl(0); h->auth1 = htonl(0); h->auth2 = htonl(0); } static inline void init_header(struct boothc_header *h, int cmd, int result, int data_len) { init_header_bare(h); h->length = htonl(data_len); h->cmd = htonl(cmd); h->result = htonl(result); } static inline void init_ticket_site_header(struct boothc_ticket_msg *msg, int cmd) { init_header(&msg->header, cmd, 0, sizeof(*msg)); } static inline void init_ticket_msg(struct boothc_ticket_msg *msg, int cmd, int rv, struct ticket_config *tk) { assert(sizeof(msg->ticket.id) == sizeof(tk->name)); init_header(&msg->header, cmd, rv, sizeof(*msg)); if (!tk) { memset(&msg->ticket, 0, sizeof(msg->ticket)); } else { memcpy(msg->ticket.id, tk->name, sizeof(msg->ticket.id)); msg->ticket.leader = htonl(get_node_id(tk->leader ?: tk->voted_for)); msg->ticket.term = htonl(tk->current_term); msg->ticket.term_valid_for = htonl(term_valid_for(tk)); - msg->ticket.prev_log_index = htonl(tk->last_applied); msg->ticket.leader_commit = htonl(tk->commit_index); } } static inline struct booth_transport const *transport(void) { return booth_transport + booth_conf->proto; } static inline const char *site_string(struct booth_site *site) { return site ? site->addr_string : "NONE"; } static inline const char *ticket_leader_string(struct ticket_config *tk) { return site_string(tk->leader); } static inline void disown_ticket(struct ticket_config *tk) { tk->leader = NULL; time(&tk->term_expires); } static inline int disown_if_expired(struct ticket_config *tk) { if (time(NULL) >= tk->term_expires || !tk->leader) { disown_ticket(tk); return 1; } return 0; } /* We allow half of the uint32_t to be used; * half of that below, half of that above the current known "good" value. * 0 UINT32_MAX * |--------------------------+----------------+------------| * | | | * |--------+-------| allowed range * | * current commit index * * So, on overflow it looks like that: * UINT32_MAX 0 * |--------------------------+-----------||---+------------| * | | | * |--------+-------| allowed range * | * current commit index * * This should be possible by using the same datatype and relying * on the under/overflow semantics. * * * Having 30 bits available, and assuming an expire time of * one minute and a (high) commit index step of 64 == 2^6 (because * of weights), we get 2^24 minutes of range - which is ~750 * years. "Should be enough for everybody." */ static inline int index_is_higher_than(uint32_t c_high, uint32_t c_low) { uint32_t diff; if (c_high == c_low) return 0; diff = c_high - c_low; if (diff < UINT32_MAX/4) return 1; diff = c_low - c_high; if (diff < UINT32_MAX/4) return 0; assert(!"commit index out of range - invalid"); } static inline uint32_t index_max2(uint32_t a, uint32_t b) { return index_is_higher_than(a, b) ? a : b; } static inline uint32_t index_max3(uint32_t a, uint32_t b, uint32_t c) { return index_max2( index_max2(a, b), c); } static inline double timeval_to_float(struct timeval tv) { return tv.tv_sec + tv.tv_usec*(double)1.0e-6; } static inline int timeval_msec(struct timeval tv) { int m; m = tv.tv_usec / 1000; if (m >= 1000) m = 999; return m; } static inline int timeval_compare(struct timeval tv1, struct timeval tv2) { if (tv1.tv_sec < tv2.tv_sec) return -1; if (tv1.tv_sec > tv2.tv_sec) return +1; if (tv1.tv_usec < tv2.tv_usec) return -1; if (tv1.tv_usec > tv2.tv_usec) return +1; return 0; } static inline int timeval_in_past(struct timeval which) { struct timeval tv; gettimeofday(&tv, NULL); return timeval_compare(tv, which) > 0; } static inline time_t next_vote_starts_at(struct ticket_config *tk) { time_t half_exp, retries_needed; /* If not owner, don't renew. */ if (tk->leader != local) return 0; /* Try to renew at half of expiry time. */ half_exp = tk->term_expires - tk->term_duration/2; /* Also start renewal if we couldn't get * a few message retransmission in the alloted * expiry time. */ retries_needed = tk->term_expires - tk->timeout * tk->retries/2; /* Return earlier timestamp. */ return half_exp < retries_needed ? half_exp : retries_needed; } static inline int should_start_renewal(struct ticket_config *tk) { time_t now, when; when = next_vote_starts_at(tk); if (!when) return 0; time(&now); return when <= now; } static inline int send_heartbeat(struct ticket_config *tk) { tk->hb_received = local->bitmask; tk->hb_sent_at = time(NULL); return ticket_broadcast(tk, OP_HEARTBEAT, RLT_SUCCESS); } static inline struct booth_site *my_vote(struct ticket_config *tk) { return tk->votes_for[ local->index ]; } static inline int count_bits(uint64_t val) { return __builtin_popcount(val); } static inline int majority_of_bits(struct ticket_config *tk, uint64_t val) { /* Use ">" to get majority decision, even for an even number * of participants. */ return count_bits(val) * 2 > booth_conf->site_count; } #endif diff --git a/src/raft.c b/src/raft.c index b45bb0e..c6b7d41 100644 --- a/src/raft.c +++ b/src/raft.c @@ -1,496 +1,495 @@ /* * Copyright (C) 2014 Philipp Marek * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This software is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #include #include #include #include #include #include "booth.h" #include "transport.h" #include "inline-fn.h" #include "config.h" #include "raft.h" #include "ticket.h" #include "log.h" inline static void clear_election(struct ticket_config *tk) { int i; struct booth_site *site; log_info("clear election"); tk->votes_received = 0; foreach_node(i, site) tk->votes_for[site->index] = NULL; } inline static void site_voted_for(struct ticket_config *tk, struct booth_site *who, struct booth_site *vote) { log_info("site \"%s\" votes for \"%s\"", who->addr_string, vote->addr_string); if (!tk->votes_for[who->index]) { tk->votes_for[who->index] = vote; tk->votes_received |= who->bitmask; } else { if (tk->votes_for[who->index] != vote) log_error("voted previously (but in same term!) for \"%s\"...", tk->votes_for[who->index]->addr_string); } } static void become_follower(struct ticket_config *tk, struct boothc_ticket_msg *msg) { uint32_t i; int duration; tk->state = ST_FOLLOWER; duration = tk->term_duration; if (msg) duration = min(duration, ntohl(msg->ticket.term_valid_for)); tk->term_expires = time(NULL) + duration; if (msg) { i = ntohl(msg->ticket.term); tk->current_term = max(i, tk->current_term); /* § 5.3 */ i = ntohl(msg->ticket.leader_commit); tk->commit_index = max(i, tk->commit_index); } ticket_write(tk); } static struct booth_site *majority_votes(struct ticket_config *tk) { int i, n; struct booth_site *v; int count[MAX_NODES] = { 0, }; for(i=0; isite_count; i++) { v = tk->votes_for[i]; if (!v) continue; n = v->index; count[n]++; log_info("Majority: %d \"%s\" wants %d \"%s\" => %d", i, booth_conf->site[i].addr_string, n, v->addr_string, count[n]); if (count[n]*2 <= booth_conf->site_count) continue; log_info("Majority reached: %d of %d for \"%s\"", count[n], booth_conf->site_count, v->addr_string); return v; } return NULL; } static int newer_term(struct ticket_config *tk, struct booth_site *sender, struct booth_site *leader, struct boothc_ticket_msg *msg) { uint32_t term; term = ntohl(msg->ticket.term); /* §5.1 */ if (term > tk->current_term) { tk->state = ST_FOLLOWER; tk->leader = leader; log_info("higher term %d vs. %d, following \"%s\"", term, tk->current_term, ticket_leader_string(tk)); tk->current_term = term; return 1; } return 0; } static int term_too_low(struct ticket_config *tk, struct booth_site *sender, struct booth_site *leader, struct boothc_ticket_msg *msg) { uint32_t term; term = ntohl(msg->ticket.term); /* §5.1 */ if (term < tk->current_term) { log_info("sending REJECT, term too low."); send_reject(sender, tk, RLT_TERM_OUTDATED); return 1; } return 0; } /* For follower. */ static int answer_HEARTBEAT ( struct ticket_config *tk, struct booth_site *sender, struct booth_site *leader, struct boothc_ticket_msg *msg ) { uint32_t term; struct boothc_ticket_msg omsg; term = ntohl(msg->ticket.term); log_debug("leader: %s, have %s; term %d vs %d", site_string(leader), ticket_leader_string(tk), term, tk->current_term); /* No reject. (?) */ if (term < tk->current_term) return 0; /* Needed? */ newer_term(tk, sender, leader, msg); become_follower(tk, msg); assert(sender == leader); tk->leader = leader; /* Yeth, mathter. */ init_ticket_msg(&omsg, OP_HEARTBEAT, RLT_SUCCESS, tk); return booth_udp_send(sender, &omsg, sizeof(omsg)); } /* For leader. */ static int process_HEARTBEAT( struct ticket_config *tk, struct booth_site *sender, struct booth_site *leader, struct boothc_ticket_msg *msg ) { uint32_t term; if (newer_term(tk, sender, leader, msg)) { /* Uh oh. Higher term?? Should we simply believe that? */ log_error("Got higher term number from"); return 0; } term = ntohl(msg->ticket.term); /* Don't send a reject. */ if (term < tk->current_term) { /* Doesn't know what he's talking about - perhaps * doesn't receive our packets? */ log_error("Stale/wrong heartbeat from \"%s\": " "term %d instead of %d", site_string(sender), term, tk->current_term); return 0; } if (term == tk->current_term && leader == tk->leader) { /* Hooray, an ACK! */ /* So at least _someone_ is listening. */ tk->hb_received |= sender->bitmask; log_debug("Got heartbeat ACK from \"%s\", %d/%d agree.", site_string(sender), count_bits(tk->hb_received), booth_conf->site_count); if (majority_of_bits(tk, tk->hb_received)) { /* OK, at least half of the nodes are reachable; * no need to do anything until * the next heartbeat should be sent. */ set_ticket_wakeup(tk); tk->retry_number = 0; } else { /* Not enough answers yet; * wait until timeout expires. */ ticket_activate_timeout(tk); } } return 0; } static int process_VOTE_FOR( struct ticket_config *tk, struct booth_site *sender, struct booth_site *leader, struct boothc_ticket_msg *msg ) { uint32_t term; struct booth_site *new_leader; term = ntohl(msg->ticket.term); if (term_too_low(tk, sender, leader, msg)) return 0; if (term == tk->current_term && tk->election_end < time(NULL)) { /* Election already ended - either by time or majority. * Ignore. */ return 0; } if (newer_term(tk, sender, leader, msg)) { clear_election(tk); } site_voted_for(tk, sender, leader); /* §5.2 */ new_leader = majority_votes(tk); if (new_leader) { tk->leader = new_leader; tk->term_expires = time(NULL) + tk->term_duration; tk->election_end = 0; tk->voted_for = NULL; if ( new_leader == local) { tk->commit_index++; // ?? tk->state = ST_LEADER; send_heartbeat(tk); ticket_write(tk); } else become_follower(tk, NULL); } set_ticket_wakeup(tk); return 0; } static int process_REJECTED( struct ticket_config *tk, struct booth_site *sender, struct booth_site *leader, struct boothc_ticket_msg *msg ) { uint32_t rv; rv = ntohl(msg->header.result); if (tk->state == ST_CANDIDATE && rv == RLT_TERM_OUTDATED) { log_info("Am out of date, become follower."); tk->leader = leader; become_follower(tk, msg); return 0; } if (tk->state == ST_CANDIDATE && rv == RLT_TERM_STILL_VALID) { log_error("There's a leader that I don't see: \"%s\"", site_string(leader)); tk->leader = leader; become_follower(tk, msg); return 0; } log_error("unhandled reject: in state %s, got %s.", state_to_string(tk->state), state_to_string(rv)); tk->leader = leader; become_follower(tk, msg); return 0; } /* §5.2 */ static int answer_REQ_VOTE( struct ticket_config *tk, struct booth_site *sender, struct booth_site *leader, struct boothc_ticket_msg *msg ) { uint32_t term; int valid; struct boothc_ticket_msg omsg; if (term_too_low(tk, sender, leader, msg)) return 0; if (newer_term(tk, sender, leader, msg)) goto vote_for_her; term = ntohl(msg->ticket.term); /* Important: Ignore duplicated packets! */ valid = term_valid_for(tk); if (valid && term == tk->current_term && sender == tk->leader) { log_debug("Duplicate OP_VOTE_FOR ignored."); return 0; } if (valid) { log_debug("no election allowed, term valid for %d??", valid); return send_reject(sender, tk, RLT_TERM_STILL_VALID); } /* §5.2, §5.4 */ - if (!tk->voted_for && - ntohl(msg->ticket.last_log_index) >= tk->last_applied) { + if (!tk->voted_for) { vote_for_her: tk->voted_for = sender; site_voted_for(tk, sender, leader); goto yes_you_can; } yes_you_can: init_ticket_msg(&omsg, OP_VOTE_FOR, RLT_SUCCESS, tk); omsg.ticket.leader = htonl(get_node_id(tk->voted_for)); return transport()->broadcast(&omsg, sizeof(omsg)); } int new_election(struct ticket_config *tk, struct booth_site *preference) { struct booth_site *new_leader; time_t now; time(&now); log_debug("start new election?, now=%" PRIi64 ", end %" PRIi64, now, tk->election_end); if (now <= tk->election_end) return 0; /* §5.2 */ tk->current_term++; tk->term_expires = 0; tk->election_end = now + tk->term_duration; log_debug("start new election! term=%d, until %" PRIi64, tk->current_term, tk->election_end); clear_election(tk); if(preference) new_leader = preference; else new_leader = (local->type == SITE) ? local : NULL; site_voted_for(tk, local, new_leader); tk->voted_for = new_leader; tk->state = ST_CANDIDATE; ticket_broadcast(tk, OP_REQ_VOTE, RLT_SUCCESS); return 0; } int raft_answer( struct ticket_config *tk, struct booth_site *from, struct booth_site *leader, struct boothc_ticket_msg *msg ) { int cmd; int rv; cmd = ntohl(msg->header.cmd); R(tk); log_debug("got message %s from \"%s\"", state_to_string(cmd), from->addr_string); switch (cmd) { case OP_REQ_VOTE: rv = answer_REQ_VOTE(tk, from, leader, msg); break; case OP_VOTE_FOR: rv = process_VOTE_FOR(tk, from, leader, msg); break; case OP_HEARTBEAT: if (tk->leader == local && tk->state == ST_LEADER) rv = process_HEARTBEAT(tk, from, leader, msg); else if (tk->leader != local && tk->state == ST_FOLLOWER) rv = answer_HEARTBEAT(tk, from, leader, msg); else assert("invalid combination - leader, follower"); break; case OP_REJECTED: rv = process_REJECTED(tk, from, leader, msg); break; default: log_error("unprocessed message, cmd %x", cmd); rv = -EINVAL; } R(tk); return rv; }