1 // Copyright (c) 2012 Pieter Wuille
2 // Distributed under the MIT/X11 software license, see the accompanying
3 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
4 #ifndef _BITCOIN_ADDRMAN
5 #define _BITCOIN_ADDRMAN 1
17 #include <openssl/rand.h>
20 /** Extended statistics about a CAddress */
21 class CAddrInfo : public CAddress
24 // where knowledge about this address first came from
27 // last successful connection by us
30 // last try whatsoever by us:
31 // int64_t CAddress::nLastTry
33 // connection attempts since last successful attempt
36 // reference count in new sets (memory only)
39 // in tried set? (memory only)
42 // position in vRandom
45 friend class CAddrMan;
50 CAddress* pthis = (CAddress*)(this);
53 READWRITE(nLastSuccess);
67 CAddrInfo(const CAddress &addrIn, const CNetAddr &addrSource) : CAddress(addrIn), source(addrSource)
72 CAddrInfo() : CAddress(), source()
77 // Calculate in which "tried" bucket this entry belongs
78 int GetTriedBucket(const std::vector<unsigned char> &nKey) const;
80 // Calculate in which "new" bucket this entry belongs, given a certain source
81 int GetNewBucket(const std::vector<unsigned char> &nKey, const CNetAddr& src) const;
83 // Calculate in which "new" bucket this entry belongs, using its default source
84 int GetNewBucket(const std::vector<unsigned char> &nKey) const
86 return GetNewBucket(nKey, source);
89 // Determine whether the statistics about this entry are bad enough so that it can just be deleted
90 bool IsTerrible(int64_t nNow = GetAdjustedTime()) const;
92 // Calculate the relative chance this entry should be given when selecting nodes to connect to
93 double GetChance(int64_t nNow = GetAdjustedTime()) const;
97 // Stochastic address manager
100 // * Only keep a limited number of addresses around, so that addr.dat and memory requirements do not grow without bound.
101 // * Keep the address tables in-memory, and asynchronously dump the entire to able in addr.dat.
102 // * Make sure no (localized) attacker can fill the entire table with his nodes/addresses.
105 // * Addresses are organized into buckets.
106 // * Address that have not yet been tried go into 256 "new" buckets.
107 // * Based on the address range (/16 for IPv4) of source of the information, 32 buckets are selected at random
108 // * The actual bucket is chosen from one of these, based on the range the address itself is located.
109 // * One single address can occur in up to 4 different buckets, to increase selection chances for addresses that
110 // are seen frequently. The chance for increasing this multiplicity decreases exponentially.
111 // * When adding a new address to a full bucket, a randomly chosen entry (with a bias favoring less recently seen
112 // ones) is removed from it first.
113 // * Addresses of nodes that are known to be accessible go into 64 "tried" buckets.
114 // * Each address range selects at random 4 of these buckets.
115 // * The actual bucket is chosen from one of these, based on the full address.
116 // * When adding a new good address to a full bucket, a randomly chosen entry (with a bias favoring less recently
117 // tried ones) is evicted from it, back to the "new" buckets.
118 // * Bucket selection is based on cryptographic hashing, using a randomly-generated 256-bit key, which should not
119 // be observable by adversaries.
120 // * Several indexes are kept for high performance. Defining DEBUG_ADDRMAN will introduce frequent (and expensive)
121 // consistency checks for the entire data structure.
123 // total number of buckets for tried addresses
124 #define ADDRMAN_TRIED_BUCKET_COUNT 64
126 // maximum allowed number of entries in buckets for tried addresses
127 #define ADDRMAN_TRIED_BUCKET_SIZE 64
129 // total number of buckets for new addresses
130 #define ADDRMAN_NEW_BUCKET_COUNT 256
132 // maximum allowed number of entries in buckets for new addresses
133 #define ADDRMAN_NEW_BUCKET_SIZE 64
135 // over how many buckets entries with tried addresses from a single group (/16 for IPv4) are spread
136 #define ADDRMAN_TRIED_BUCKETS_PER_GROUP 4
138 // over how many buckets entries with new addresses originating from a single group are spread
139 #define ADDRMAN_NEW_BUCKETS_PER_SOURCE_GROUP 32
141 // in how many buckets for entries with new addresses a single address may occur
142 #define ADDRMAN_NEW_BUCKETS_PER_ADDRESS 4
144 // how many entries in a bucket with tried addresses are inspected, when selecting one to replace
145 #define ADDRMAN_TRIED_ENTRIES_INSPECT_ON_EVICT 4
147 // how old addresses can maximally be
148 #define ADDRMAN_HORIZON_DAYS 30
150 // after how many failed attempts we give up on a new node
151 #define ADDRMAN_RETRIES 3
153 // how many successive failures are allowed ...
154 #define ADDRMAN_MAX_FAILURES 10
156 // ... in at least this many days
157 #define ADDRMAN_MIN_FAIL_DAYS 7
159 // the maximum percentage of nodes to return in a getaddr call
160 #define ADDRMAN_GETADDR_MAX_PCT 23
162 // the maximum number of nodes to return in a getaddr call
163 #define ADDRMAN_GETADDR_MAX 2500
165 /** Stochastical (IP) address manager */
169 // critical section to protect the inner data structures
170 mutable CCriticalSection cs;
172 // secret key to randomize bucket select with
173 std::vector<unsigned char> nKey;
178 // table with information about all nIds
179 std::map<int, CAddrInfo> mapInfo;
181 // find an nId based on its network address
182 std::map<CNetAddr, int> mapAddr;
184 // randomly-ordered vector of all nIds
185 std::vector<int> vRandom;
187 // number of "tried" entries
190 // list of "tried" buckets
191 std::vector<std::vector<int> > vvTried;
193 // number of (unique) "new" entries
196 // list of "new" buckets
197 std::vector<std::set<int> > vvNew;
202 CAddrInfo* Find(const CNetAddr& addr, int *pnId = NULL);
204 // find an entry, creating it if necessary.
205 // nTime and nServices of found node is updated, if necessary.
206 CAddrInfo* Create(const CAddress &addr, const CNetAddr &addrSource, int *pnId = NULL);
208 // Swap two elements in vRandom.
209 void SwapRandom(unsigned int nRandomPos1, unsigned int nRandomPos2);
211 // Return position in given bucket to replace.
212 int SelectTried(int nKBucket);
214 // Remove an element from a "new" bucket.
215 // This is the only place where actual deletes occur.
216 // They are never deleted while in the "tried" table, only possibly evicted back to the "new" table.
217 int ShrinkNew(int nUBucket);
219 // Move an entry from the "new" table(s) to the "tried" table
220 // @pre vvUnkown[nOrigin].count(nId) != 0
221 void MakeTried(CAddrInfo& info, int nId, int nOrigin);
223 // Mark an entry "good", possibly moving it from "new" to "tried".
224 void Good_(const CService &addr, int64_t nTime);
226 // Add an entry to the "new" table.
227 bool Add_(const CAddress &addr, const CNetAddr& source, int64_t nTimePenalty);
229 // Mark an entry as attempted to connect.
230 void Attempt_(const CService &addr, int64_t nTime);
232 // Select an address to connect to.
233 // nUnkBias determines how much to favor new addresses over tried ones (min=0, max=100)
234 CAddress Select_(int nUnkBias);
237 // Perform consistency check. Returns an error code or zero.
241 // Select several addresses at once.
242 void GetAddr_(std::vector<CAddress> &vAddr);
243 void GetOnlineAddr_(std::vector<CAddrInfo> &vAddr);
245 // Mark an entry as currently-connected-to.
246 void Connected_(const CService &addr, int64_t nTime);
250 typedef std::map<int, int> MapUnkIds; // For MSVC macro
263 *am = const_cast<CAddrMan*>(this);
268 nUBuckets = ADDRMAN_NEW_BUCKET_COUNT;
270 READWRITE(nUBuckets);
274 for (std::map<int, CAddrInfo>::iterator it = am->mapInfo.begin(); it != am->mapInfo.end(); it++)
277 break; // this means nNew was wrong, oh ow
278 mapUnkIds[(*it).first] = nIds;
281 &info = (*it).second;
290 for (std::map<int, CAddrInfo>::iterator it = am->mapInfo.begin(); it != am->mapInfo.end(); it++)
293 break; /* this means nTried was wrong, oh ow */
296 &info = (*it).second;
305 std::vector<std::set<int> >::iterator it = am->vvNew.begin();
306 it != am->vvNew.end();
314 nSize = int( vNew.size() );
317 for (std::set<int>::iterator it2 = vNew.begin(); it2 != vNew.end(); it2++)
320 nIndex = mapUnkIds[*it2];
330 READWRITE(nUBuckets);
336 std::vector<std::vector<int> >(
337 ADDRMAN_TRIED_BUCKET_COUNT,
341 std::vector<std::set<int> >(
342 ADDRMAN_NEW_BUCKET_COUNT,
345 for (int n = 0; n < am->nNew; n++)
348 &info = am->mapInfo[n];
351 am->mapAddr[info] = n;
352 info.nRandomPos = int( vRandom.size() );
353 am->vRandom.push_back(n);
354 if (nUBuckets != ADDRMAN_NEW_BUCKET_COUNT)
356 am->vvNew[info.GetNewBucket(am->nKey)].insert(n);
360 am->nIdCount = am->nNew;
365 for (int n = 0; n < am->nTried; n++)
373 &vTried = am->vvTried[info.GetTriedBucket(am->nKey)];
375 if (vTried.size() < ADDRMAN_TRIED_BUCKET_SIZE)
377 info.nRandomPos = int( vRandom.size() );
378 info.fInTried = true;
379 am->vRandom.push_back(am->nIdCount);
380 am->mapInfo[am->nIdCount] = info;
381 am->mapAddr[info] = am->nIdCount;
382 vTried.push_back(am->nIdCount);
391 for (int b = 0; b < nUBuckets; b++)
394 &vNew = am->vvNew[b];
400 for (int n = 0; n < nSize; n++)
408 &info = am->mapInfo[nIndex];
411 (nUBuckets == ADDRMAN_NEW_BUCKET_COUNT) &&
412 (info.nRefCount < ADDRMAN_NEW_BUCKETS_PER_ADDRESS)
424 CAddrMan() : vRandom(0), vvTried(ADDRMAN_TRIED_BUCKET_COUNT, std::vector<int>(0)), vvNew(ADDRMAN_NEW_BUCKET_COUNT, std::set<int>())
427 RAND_bytes(&nKey[0], 32);
434 // Return the number of (unique) addresses in all tables.
437 return (int) vRandom.size();
448 printf("ADDRMAN CONSISTENCY CHECK FAILED!!! err=%i\n", err);
453 // Add a single address.
454 bool Add(const CAddress &addr, const CNetAddr& source, int64_t nTimePenalty = 0)
460 fRet |= Add_(addr, source, nTimePenalty);
464 printf("Added %s from %s: %i tried, %i new\n", addr.ToStringIPPort().c_str(), source.ToString().c_str(), nTried, nNew);
468 // Add multiple addresses.
469 bool Add(const std::vector<CAddress> &vAddr, const CNetAddr& source, int64_t nTimePenalty = 0)
475 for (std::vector<CAddress>::const_iterator it = vAddr.begin(); it != vAddr.end(); it++)
476 nAdd += Add_(*it, source, nTimePenalty) ? 1 : 0;
480 printf("Added %i addresses from %s: %i tried, %i new\n", nAdd, source.ToString().c_str(), nTried, nNew);
484 // Mark an entry as accessible.
485 void Good(const CService &addr, int64_t nTime = GetAdjustedTime())
495 // Mark an entry as connection attempted to.
496 void Attempt(const CService &addr, int64_t nTime = GetAdjustedTime())
501 Attempt_(addr, nTime);
506 // Choose an address to connect to.
507 // nUnkBias determines how much "new" entries are favored over "tried" ones (0-100).
508 CAddress Select(int nUnkBias = 50)
514 addrRet = Select_(nUnkBias);
520 // Return a bunch of addresses, selected at random.
521 std::vector<CAddress> GetAddr()
524 std::vector<CAddress> vAddr;
533 std::vector<CAddrInfo> GetOnlineAddr()
536 std::vector<CAddrInfo> vAddr;
539 GetOnlineAddr_(vAddr);
545 // Mark an entry as currently-connected-to.
546 void Connected(const CService &addr, int64_t nTime = GetAdjustedTime())
551 Connected_(addr, nTime);