diff options
Diffstat (limited to 'src/addrman.h')
| -rw-r--r-- | src/addrman.h | 499 |
1 files changed, 499 insertions, 0 deletions
diff --git a/src/addrman.h b/src/addrman.h new file mode 100644 index 0000000000..350ecb2709 --- /dev/null +++ b/src/addrman.h @@ -0,0 +1,499 @@ +// Copyright (c) 2012 Pieter Wuille +// Distributed under the MIT/X11 software license, see the accompanying +// file license.txt or http://www.opensource.org/licenses/mit-license.php. +#ifndef _BITCOIN_ADDRMAN +#define _BITCOIN_ADDRMAN 1 + +#include "netbase.h" +#include "protocol.h" +#include "util.h" + + +#include <map> +#include <vector> + +#include <openssl/rand.h> + + +// Extended statistics about a CAddress +class CAddrInfo : public CAddress +{ +private: + // where knowledge about this address first came from + CNetAddr source; + + // last succesfull connection by us + int64 nLastSuccess; + + // last try whatsoever by us: + // int64 CAddress::nLastTry + + // connection attempts since last succesful attempt + int nAttempts; + + // reference count in new sets (memory only) + int nRefCount; + + // in tried set? (memory only) + bool fInTried; + + // position in vRandom + int nRandomPos; + + friend class CAddrMan; + +public: + + IMPLEMENT_SERIALIZE( + CAddress* pthis = (CAddress*)(this); + READWRITE(*pthis); + READWRITE(source); + READWRITE(nLastSuccess); + READWRITE(nAttempts); + ) + + void Init() + { + nLastSuccess = 0; + nLastTry = 0; + nAttempts = 0; + nRefCount = 0; + fInTried = false; + nRandomPos = -1; + } + + CAddrInfo(const CAddress &addrIn, const CNetAddr &addrSource) : CAddress(addrIn) + { + Init(); + } + + CAddrInfo() : CAddress(), source() + { + Init(); + } + + // Calculate in which "tried" bucket this entry belongs + int GetTriedBucket(const std::vector<unsigned char> &nKey) const; + + // Calculate in which "new" bucket this entry belongs, given a certain source + int GetNewBucket(const std::vector<unsigned char> &nKey, const CNetAddr& src) const; + + // Calculate in which "new" bucket this entry belongs, using its default source + int GetNewBucket(const std::vector<unsigned char> &nKey) const + { + return GetNewBucket(nKey, source); + } + + // Determine whether the statistics about this entry are bad enough so that it can just be deleted + bool IsTerrible(int64 nNow = GetAdjustedTime()) const; + + // Calculate the relative chance this entry should be given when selecting nodes to connect to + double GetChance(int64 nNow = GetAdjustedTime()) const; + +}; + +// Stochastic address manager +// +// Design goals: +// * Only keep a limited number of addresses around, so that addr.dat and memory requirements do not grow without bound. +// * Keep the address tables in-memory, and asynchronously dump the entire to able in addr.dat. +// * Make sure no (localized) attacker can fill the entire table with his nodes/addresses. +// +// To that end: +// * Addresses are organized into buckets. +// * Address that have not yet been tried go into 256 "new" buckets. +// * Based on the address range (/16 for IPv4) of source of the information, 32 buckets are selected at random +// * The actual bucket is chosen from one of these, based on the range the address itself is located. +// * One single address can occur in up to 4 different buckets, to increase selection chances for addresses that +// are seen frequently. The chance for increasing this multiplicity decreases exponentially. +// * When adding a new address to a full bucket, a randomly chosen entry (with a bias favoring less recently seen +// ones) is removed from it first. +// * Addresses of nodes that are known to be accessible go into 64 "tried" buckets. +// * Each address range selects at random 4 of these buckets. +// * The actual bucket is chosen from one of these, based on the full address. +// * When adding a new good address to a full bucket, a randomly chosen entry (with a bias favoring less recently +// tried ones) is evicted from it, back to the "new" buckets. +// * Bucket selection is based on cryptographic hashing, using a randomly-generated 256-bit key, which should not +// be observable by adversaries. +// * Several indexes are kept for high performance. Defining DEBUG_ADDRMAN will introduce frequent (and expensive) +// consistency checks for the entire datastructure. + +// total number of buckets for tried addresses +#define ADDRMAN_TRIED_BUCKET_COUNT 64 + +// maximum allowed number of entries in buckets for tried addresses +#define ADDRMAN_TRIED_BUCKET_SIZE 64 + +// total number of buckets for new addresses +#define ADDRMAN_NEW_BUCKET_COUNT 256 + +// maximum allowed number of entries in buckets for new addresses +#define ADDRMAN_NEW_BUCKET_SIZE 64 + +// over how many buckets entries with tried addresses from a single group (/16 for IPv4) are spread +#define ADDRMAN_TRIED_BUCKETS_PER_GROUP 4 + +// over how many buckets entries with new addresses originating from a single group are spread +#define ADDRMAN_NEW_BUCKETS_PER_SOURCE_GROUP 32 + +// in how many buckets for entries with new addresses a single address may occur +#define ADDRMAN_NEW_BUCKETS_PER_ADDRESS 4 + +// how many entries in a bucket with tried addresses are inspected, when selecting one to replace +#define ADDRMAN_TRIED_ENTRIES_INSPECT_ON_EVICT 4 + +// how old addresses can maximally be +#define ADDRMAN_HORIZON_DAYS 30 + +// after how many failed attempts we give up on a new node +#define ADDRMAN_RETRIES 3 + +// how many successive failures are allowed ... +#define ADDRMAN_MAX_FAILURES 10 + +// ... in at least this many days +#define ADDRMAN_MIN_FAIL_DAYS 7 + +// the maximum percentage of nodes to return in a getaddr call +#define ADDRMAN_GETADDR_MAX_PCT 23 + +// the maximum number of nodes to return in a getaddr call +#define ADDRMAN_GETADDR_MAX 2500 + +class CAddrMan +{ +private: + // critical section to protect the inner data structures + mutable CCriticalSection cs; + + // secret key to randomize bucket select with + std::vector<unsigned char> nKey; + + // last used nId + int nIdCount; + + // table with information about all nId's + std::map<int, CAddrInfo> mapInfo; + + // find an nId based on its network address + std::map<CNetAddr, int> mapAddr; + + // randomly-ordered vector of all nId's + std::vector<int> vRandom; + + // number of "tried" entries + int nTried; + + // list of "tried" buckets + std::vector<std::vector<int> > vvTried; + + // number of (unique) "new" entries + int nNew; + + // list of "new" buckets + std::vector<std::set<int> > vvNew; + +protected: + + // Find an entry. + CAddrInfo* Find(const CNetAddr& addr, int *pnId = NULL); + + // find an entry, creating it if necessary. + // nTime and nServices of found node is updated, if necessary. + CAddrInfo* Create(const CAddress &addr, const CNetAddr &addrSource, int *pnId = NULL); + + // Swap two elements in vRandom. + void SwapRandom(int nRandomPos1, int nRandomPos2); + + // Return position in given bucket to replace. + int SelectTried(int nKBucket); + + // Remove an element from a "new" bucket. + // This is the only place where actual deletes occur. + // They are never deleted while in the "tried" table, only possibly evicted back to the "new" table. + int ShrinkNew(int nUBucket); + + // Move an entry from the "new" table(s) to the "tried" table + // @pre vvUnkown[nOrigin].count(nId) != 0 + void MakeTried(CAddrInfo& info, int nId, int nOrigin); + + // Mark an entry "good", possibly moving it from "new" to "tried". + void Good_(const CService &addr, int64 nTime); + + // Add an entry to the "new" table. + bool Add_(const CAddress &addr, const CNetAddr& source, int64 nTimePenalty); + + // Mark an entry as attempted to connect. + void Attempt_(const CService &addr, int64 nTime); + + // Select an address to connect to. + // nUnkBias determines how much to favor new addresses over tried ones (min=0, max=100) + CAddress Select_(int nUnkBias); + +#ifdef DEBUG_ADDRMAN + // Perform consistency check. Returns an error code or zero. + int Check_(); +#endif + + // Select several addresses at once. + void GetAddr_(std::vector<CAddress> &vAddr); + + // Mark an entry as currently-connected-to. + void Connected_(const CService &addr, int64 nTime); + +public: + + IMPLEMENT_SERIALIZE + (({ + // serialized format: + // * version byte (currently 0) + // * nKey + // * nNew + // * nTried + // * number of "new" buckets + // * all nNew addrinfo's in vvNew + // * all nTried addrinfo's in vvTried + // * for each bucket: + // * number of elements + // * for each element: index + // + // Notice that vvTried, mapAddr and vVector are never encoded explicitly; + // they are instead reconstructed from the other information. + // + // vvNew is serialized, but only used if ADDRMAN_UNKOWN_BUCKET_COUNT didn't change, + // otherwise it is reconstructed as well. + // + // This format is more complex, but significantly smaller (at most 1.5 MiB), and supports + // changes to the ADDRMAN_ parameters without breaking the on-disk structure. + CRITICAL_BLOCK(cs) + { + unsigned char nVersion = 0; + READWRITE(nVersion); + READWRITE(nKey); + READWRITE(nNew); + READWRITE(nTried); + + CAddrMan *am = const_cast<CAddrMan*>(this); + if (fWrite) + { + int nUBuckets = ADDRMAN_NEW_BUCKET_COUNT; + READWRITE(nUBuckets); + std::map<int, int> mapUnkIds; + int nIds = 0; + for (std::map<int, CAddrInfo>::iterator it = am->mapInfo.begin(); it != am->mapInfo.end(); it++) + { + if (nIds == nNew) break; // this means nNew was wrong, oh ow + mapUnkIds[(*it).first] = nIds; + CAddrInfo &info = (*it).second; + if (info.nRefCount) + { + READWRITE(info); + nIds++; + } + } + nIds = 0; + for (std::map<int, CAddrInfo>::iterator it = am->mapInfo.begin(); it != am->mapInfo.end(); it++) + { + if (nIds == nTried) break; // this means nTried was wrong, oh ow + CAddrInfo &info = (*it).second; + if (info.fInTried) + { + READWRITE(info); + nIds++; + } + } + for (std::vector<std::set<int> >::iterator it = am->vvNew.begin(); it != am->vvNew.end(); it++) + { + const std::set<int> &vNew = (*it); + int nSize = vNew.size(); + READWRITE(nSize); + for (std::set<int>::iterator it2 = vNew.begin(); it2 != vNew.end(); it2++) + { + int nIndex = mapUnkIds[*it2]; + READWRITE(nIndex); + } + } + } else { + int nUBuckets = 0; + READWRITE(nUBuckets); + am->nIdCount = 0; + am->mapInfo.clear(); + am->mapAddr.clear(); + am->vRandom.clear(); + am->vvTried = std::vector<std::vector<int> >(ADDRMAN_TRIED_BUCKET_COUNT, std::vector<int>(0)); + am->vvNew = std::vector<std::set<int> >(ADDRMAN_NEW_BUCKET_COUNT, std::set<int>()); + for (int n = 0; n < am->nNew; n++) + { + CAddrInfo &info = am->mapInfo[n]; + READWRITE(info); + am->mapAddr[info] = n; + info.nRandomPos = vRandom.size(); + am->vRandom.push_back(n); + if (nUBuckets != ADDRMAN_NEW_BUCKET_COUNT) + { + am->vvNew[info.GetNewBucket(am->nKey)].insert(n); + info.nRefCount++; + } + } + am->nIdCount = am->nNew; + int nLost = 0; + for (int n = 0; n < am->nTried; n++) + { + CAddrInfo info; + READWRITE(info); + std::vector<int> &vTried = am->vvTried[info.GetTriedBucket(am->nKey)]; + if (vTried.size() < ADDRMAN_TRIED_BUCKET_SIZE) + { + info.nRandomPos = vRandom.size(); + info.fInTried = true; + am->vRandom.push_back(am->nIdCount); + am->mapInfo[am->nIdCount] = info; + am->mapAddr[info] = am->nIdCount; + vTried.push_back(am->nIdCount); + am->nIdCount++; + } else { + nLost++; + } + } + am->nTried -= nLost; + for (int b = 0; b < nUBuckets; b++) + { + std::set<int> &vNew = am->vvNew[b]; + int nSize = 0; + READWRITE(nSize); + for (int n = 0; n < nSize; n++) + { + int nIndex = 0; + READWRITE(nIndex); + CAddrInfo &info = am->mapInfo[nIndex]; + if (nUBuckets == ADDRMAN_NEW_BUCKET_COUNT && info.nRefCount < ADDRMAN_NEW_BUCKETS_PER_ADDRESS) + { + info.nRefCount++; + vNew.insert(nIndex); + } + } + } + } + } + });) + + CAddrMan() : vRandom(0), vvTried(ADDRMAN_TRIED_BUCKET_COUNT, std::vector<int>(0)), vvNew(ADDRMAN_NEW_BUCKET_COUNT, std::set<int>()) + { + nKey.resize(32); + RAND_bytes(&nKey[0], 32); + + nIdCount = 0; + nTried = 0; + nNew = 0; + } + + // Return the number of (unique) addresses in all tables. + int size() + { + return vRandom.size(); + } + + // Consistency check + void Check() + { +#ifdef DEBUG_ADDRMAN + CRITICAL_BLOCK(cs) + { + int err; + if ((err=Check_())) + printf("ADDRMAN CONSISTENCY CHECK FAILED!!! err=%i\n", err); + } +#endif + } + + // Add a single address. + bool Add(const CAddress &addr, const CNetAddr& source, int64 nTimePenalty = 0) + { + bool fRet = false; + CRITICAL_BLOCK(cs) + { + Check(); + fRet |= Add_(addr, source, nTimePenalty); + Check(); + } + if (fRet) + printf("Added %s from %s: %i tried, %i new\n", addr.ToStringIPPort().c_str(), source.ToString().c_str(), nTried, nNew); + return fRet; + } + + // Add multiple addresses. + bool Add(const std::vector<CAddress> &vAddr, const CNetAddr& source, int64 nTimePenalty = 0) + { + int nAdd = 0; + CRITICAL_BLOCK(cs) + { + Check(); + for (std::vector<CAddress>::const_iterator it = vAddr.begin(); it != vAddr.end(); it++) + nAdd += Add_(*it, source, nTimePenalty) ? 1 : 0; + Check(); + } + if (nAdd) + printf("Added %i addresses from %s: %i tried, %i new\n", nAdd, source.ToString().c_str(), nTried, nNew); + return nAdd > 0; + } + + // Mark an entry as accessible. + void Good(const CService &addr, int64 nTime = GetAdjustedTime()) + { + CRITICAL_BLOCK(cs) + { + Check(); + Good_(addr, nTime); + Check(); + } + } + + // Mark an entry as connection attempted to. + void Attempt(const CService &addr, int64 nTime = GetAdjustedTime()) + { + CRITICAL_BLOCK(cs) + { + Check(); + Attempt_(addr, nTime); + Check(); + } + } + + // Choose an address to connect to. + // nUnkBias determines how much "new" entries are favored over "tried" ones (0-100). + CAddress Select(int nUnkBias = 50) + { + CAddress addrRet; + CRITICAL_BLOCK(cs) + { + Check(); + addrRet = Select_(nUnkBias); + Check(); + } + return addrRet; + } + + // Return a bunch of addresses, selected at random. + std::vector<CAddress> GetAddr() + { + Check(); + std::vector<CAddress> vAddr; + CRITICAL_BLOCK(cs) + GetAddr_(vAddr); + Check(); + return vAddr; + } + + // Mark an entry as currently-connected-to. + void Connected(const CService &addr, int64 nTime = GetAdjustedTime()) + { + CRITICAL_BLOCK(cs) + { + Check(); + Connected_(addr, nTime); + Check(); + } + } +}; + +#endif |