From b41d9eac22f3e19f2765efc61fad44cb5dfdf087 Mon Sep 17 00:00:00 2001 From: Oleg Girko Date: Sat, 2 Sep 2017 21:07:11 +0100 Subject: [PATCH] Backport Bitcoin PR#7868: net: Split DNS resolving functionality out of net structures (#1601) * net: require lookup functions to specify all arguments To make it clear where DNS resolves are happening * net: manually resolve dns seed sources Note: Some seeds aren't actually returning an IP for their name entries, so they're being added to addrman with a source of [::]. This commit shouldn't change that behavior, for better or worse. * net: resolve outside of storage structures Rather than allowing CNetAddr/CService/CSubNet to launch DNS queries, require that addresses are already resolved. This greatly simplifies async resolve logic, and makes it harder to accidentally leak DNS queries. * net: disable resolving from storage structures CNetAddr/CService/CSubnet can no longer resolve DNS. --- src/init.cpp | 7 ++++--- src/net.cpp | 14 +++++++++++--- src/netbase.cpp | 28 ++++++++++++++-------------- src/netbase.h | 20 ++++++++++---------- src/torcontrol.cpp | 2 +- 5 files changed, 40 insertions(+), 31 deletions(-) diff --git a/src/init.cpp b/src/init.cpp index c9fdd1a43..55bda1f51 100644 --- a/src/init.cpp +++ b/src/init.cpp @@ -1444,10 +1444,11 @@ bool AppInit2(boost::thread_group& threadGroup, CScheduler& scheduler) if (mapArgs.count("-externalip")) { BOOST_FOREACH(const std::string& strAddr, mapMultiArgs["-externalip"]) { - CService addrLocal(strAddr, GetListenPort(), fNameLookup); - if (!addrLocal.IsValid()) + CService addrLocal; + if (Lookup(strAddr.c_str(), addrLocal, GetListenPort(), fNameLookup) && addrLocal.IsValid()) + AddLocal(addrLocal, LOCAL_MANUAL); + else return InitError(strprintf(_("Cannot resolve -externalip address: '%s'"), strAddr)); - AddLocal(CService(strAddr, GetListenPort(), fNameLookup), LOCAL_MANUAL); } } diff --git a/src/net.cpp b/src/net.cpp index 1d54005f5..b6da8f55f 100644 --- a/src/net.cpp +++ b/src/net.cpp @@ -1523,7 +1523,7 @@ void CConnman::ThreadDNSAddressSeed() } else { std::vector vIPs; std::vector vAdd; - if (LookupHost(seed.host.c_str(), vIPs)) + if (LookupHost(seed.host.c_str(), vIPs, 0, true)) { BOOST_FOREACH(const CNetAddr& ip, vIPs) { @@ -1534,7 +1534,15 @@ void CConnman::ThreadDNSAddressSeed() found++; } } - addrman.Add(vAdd, CNetAddr(seed.name, true)); + // TODO: The seed name resolve may fail, yielding an IP of [::], which results in + // addrman assigning the same source to results from different seeds. + // This should switch to a hard-coded stable dummy IP for each seed name, so that the + // resolve is not required at all. + if (!vIPs.empty()) { + CService seedSource; + Lookup(seed.name.c_str(), seedSource, 0, true); + addrman.Add(vAdd, seedSource); + } } } @@ -2039,7 +2047,7 @@ void Discover(boost::thread_group& threadGroup) if (gethostname(pszHostName, sizeof(pszHostName)) != SOCKET_ERROR) { std::vector vaddr; - if (LookupHost(pszHostName, vaddr)) + if (LookupHost(pszHostName, vaddr, 0, true)) { BOOST_FOREACH (const CNetAddr &addr, vaddr) { diff --git a/src/netbase.cpp b/src/netbase.cpp index eff8062d3..433b96844 100644 --- a/src/netbase.cpp +++ b/src/netbase.cpp @@ -681,19 +681,19 @@ CNetAddr::CNetAddr(const struct in6_addr& ipv6Addr) SetRaw(NET_IPV6, (const uint8_t*)&ipv6Addr); } -CNetAddr::CNetAddr(const char *pszIp, bool fAllowLookup) +CNetAddr::CNetAddr(const char *pszIp) { Init(); std::vector vIP; - if (LookupHost(pszIp, vIP, 1, fAllowLookup)) + if (LookupHost(pszIp, vIP, 1, false)) *this = vIP[0]; } -CNetAddr::CNetAddr(const std::string &strIp, bool fAllowLookup) +CNetAddr::CNetAddr(const std::string &strIp) { Init(); std::vector vIP; - if (LookupHost(strIp.c_str(), vIP, 1, fAllowLookup)) + if (LookupHost(strIp.c_str(), vIP, 1, false)) *this = vIP[0]; } @@ -1119,35 +1119,35 @@ bool CService::SetSockAddr(const struct sockaddr *paddr) } } -CService::CService(const char *pszIpPort, bool fAllowLookup) +CService::CService(const char *pszIpPort) { Init(); CService ip; - if (Lookup(pszIpPort, ip, 0, fAllowLookup)) + if (Lookup(pszIpPort, ip, 0, false)) *this = ip; } -CService::CService(const char *pszIpPort, int portDefault, bool fAllowLookup) +CService::CService(const char *pszIpPort, int portDefault) { Init(); CService ip; - if (Lookup(pszIpPort, ip, portDefault, fAllowLookup)) + if (Lookup(pszIpPort, ip, portDefault, false)) *this = ip; } -CService::CService(const std::string &strIpPort, bool fAllowLookup) +CService::CService(const std::string &strIpPort) { Init(); CService ip; - if (Lookup(strIpPort.c_str(), ip, 0, fAllowLookup)) + if (Lookup(strIpPort.c_str(), ip, 0, false)) *this = ip; } -CService::CService(const std::string &strIpPort, int portDefault, bool fAllowLookup) +CService::CService(const std::string &strIpPort, int portDefault) { Init(); CService ip; - if (Lookup(strIpPort.c_str(), ip, portDefault, fAllowLookup)) + if (Lookup(strIpPort.c_str(), ip, portDefault, false)) *this = ip; } @@ -1240,7 +1240,7 @@ CSubNet::CSubNet(): memset(netmask, 0, sizeof(netmask)); } -CSubNet::CSubNet(const std::string &strSubnet, bool fAllowLookup) +CSubNet::CSubNet(const std::string &strSubnet) { size_t slash = strSubnet.find_last_of('/'); std::vector vIP; @@ -1250,7 +1250,7 @@ CSubNet::CSubNet(const std::string &strSubnet, bool fAllowLookup) memset(netmask, 255, sizeof(netmask)); std::string strAddress = strSubnet.substr(0, slash); - if (LookupHost(strAddress.c_str(), vIP, 1, fAllowLookup)) + if (LookupHost(strAddress.c_str(), vIP, 1, false)) { network = vIP[0]; if (slash != strSubnet.npos) diff --git a/src/netbase.h b/src/netbase.h index 2eea8d5d8..8cf3f09fd 100644 --- a/src/netbase.h +++ b/src/netbase.h @@ -48,8 +48,8 @@ class CNetAddr public: CNetAddr(); CNetAddr(const struct in_addr& ipv4Addr); - explicit CNetAddr(const char *pszIp, bool fAllowLookup = false); - explicit CNetAddr(const std::string &strIp, bool fAllowLookup = false); + explicit CNetAddr(const char *pszIp); + explicit CNetAddr(const std::string &strIp); void Init(); void SetIP(const CNetAddr& ip); @@ -118,7 +118,7 @@ class CSubNet public: CSubNet(); - explicit CSubNet(const std::string &strSubnet, bool fAllowLookup = false); + explicit CSubNet(const std::string &strSubnet); //constructor for single ip subnet (/32 or /128) explicit CSubNet(const CNetAddr &addr); @@ -153,10 +153,10 @@ class CService : public CNetAddr CService(const CNetAddr& ip, unsigned short port); CService(const struct in_addr& ipv4Addr, unsigned short port); CService(const struct sockaddr_in& addr); - explicit CService(const char *pszIpPort, int portDefault, bool fAllowLookup = false); - explicit CService(const char *pszIpPort, bool fAllowLookup = false); - explicit CService(const std::string& strIpPort, int portDefault, bool fAllowLookup = false); - explicit CService(const std::string& strIpPort, bool fAllowLookup = false); + explicit CService(const char *pszIpPort, int portDefault); + explicit CService(const char *pszIpPort); + explicit CService(const std::string& strIpPort, int portDefault); + explicit CService(const std::string& strIpPort); void Init(); void SetPort(unsigned short portIn); unsigned short GetPort() const; @@ -205,9 +205,9 @@ bool GetProxy(enum Network net, proxyType &proxyInfoOut); bool IsProxy(const CNetAddr &addr); bool SetNameProxy(const proxyType &addrProxy); bool HaveNameProxy(); -bool LookupHost(const char *pszName, std::vector& vIP, unsigned int nMaxSolutions = 0, bool fAllowLookup = true); -bool Lookup(const char *pszName, CService& addr, int portDefault = 0, bool fAllowLookup = true); -bool Lookup(const char *pszName, std::vector& vAddr, int portDefault = 0, bool fAllowLookup = true, unsigned int nMaxSolutions = 0); +bool LookupHost(const char *pszName, std::vector& vIP, unsigned int nMaxSolutions, bool fAllowLookup); +bool Lookup(const char *pszName, CService& addr, int portDefault, bool fAllowLookup); +bool Lookup(const char *pszName, std::vector& vAddr, int portDefault, bool fAllowLookup, unsigned int nMaxSolutions); bool LookupNumeric(const char *pszName, CService& addr, int portDefault = 0); bool ConnectSocket(const CService &addr, SOCKET& hSocketRet, int nTimeout, bool *outProxyConnectionFailed = 0); bool ConnectSocketByName(CService &addr, SOCKET& hSocketRet, const char *pszDest, int portDefault, int nTimeout, bool *outProxyConnectionFailed = 0); diff --git a/src/torcontrol.cpp b/src/torcontrol.cpp index f77a60eb5..6ee1ee2e5 100644 --- a/src/torcontrol.cpp +++ b/src/torcontrol.cpp @@ -434,7 +434,7 @@ void TorController::add_onion_cb(TorControlConnection& conn, const TorControlRep private_key = i->second; } - service = CService(service_id+".onion", GetListenPort(), false); + service = CService(service_id+".onion", GetListenPort()); LogPrintf("tor: Got service ID %s, advertising service %s\n", service_id, service.ToString()); if (WriteBinaryFile(GetPrivateKeyFile(), private_key)) { LogPrint("tor", "tor: Cached service private key to %s\n", GetPrivateKeyFile());