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688 lines
19 KiB
C++
688 lines
19 KiB
C++
#include <handlers/exit.hpp>
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#include <dns/dns.hpp>
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#include <net/net.hpp>
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#include <path/path_context.hpp>
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#include <router/abstractrouter.hpp>
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#include <util/str.hpp>
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#include <util/bits.hpp>
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#include <cassert>
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namespace llarp
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{
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namespace handlers
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{
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ExitEndpoint::ExitEndpoint(const std::string& name, AbstractRouter* r)
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: m_Router(r)
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, m_Resolver(std::make_shared<dns::Proxy>(r->netloop(), r->logic(), this))
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, m_Name(name)
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, m_LocalResolverAddr("127.0.0.1", 53)
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, m_InetToNetwork(name + "_exit_rx", r->netloop(), r->netloop())
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{
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m_ShouldInitTun = true;
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}
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ExitEndpoint::~ExitEndpoint() = default;
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util::StatusObject
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ExitEndpoint::ExtractStatus() const
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{
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util::StatusObject obj{{"permitExit", m_PermitExit}, {"ip", m_IfAddr.ToString()}};
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util::StatusObject exitsObj{};
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for (const auto& item : m_ActiveExits)
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{
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exitsObj[item.first.ToString()] = item.second->ExtractStatus();
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}
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obj["exits"] = exitsObj;
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return obj;
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}
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bool
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ExitEndpoint::SupportsV6() const
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{
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return m_UseV6;
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}
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bool
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ExitEndpoint::ShouldHookDNSMessage(const dns::Message& msg) const
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{
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if (msg.questions.size() == 0)
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return false;
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// always hook ptr for ranges we own
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if (msg.questions[0].qtype == dns::qTypePTR)
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{
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huint128_t ip;
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if (!dns::DecodePTR(msg.questions[0].qname, ip))
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return false;
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return m_OurRange.Contains(ip);
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}
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if (msg.questions[0].qtype == dns::qTypeA || msg.questions[0].qtype == dns::qTypeCNAME
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|| msg.questions[0].qtype == dns::qTypeAAAA)
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{
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if (msg.questions[0].IsName("localhost.loki"))
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return true;
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if (msg.questions[0].HasTLD(".snode"))
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return true;
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}
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return false;
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}
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bool
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ExitEndpoint::HandleHookedDNSMessage(dns::Message msg, std::function<void(dns::Message)> reply)
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{
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if (msg.questions[0].qtype == dns::qTypePTR)
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{
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huint128_t ip;
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if (!dns::DecodePTR(msg.questions[0].qname, ip))
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return false;
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if (ip == m_IfAddr)
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{
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RouterID us = GetRouter()->pubkey();
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msg.AddAReply(us.ToString(), 300);
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}
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else
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{
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auto itr = m_IPToKey.find(ip);
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if (itr != m_IPToKey.end() && m_SNodeKeys.find(itr->second) != m_SNodeKeys.end())
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{
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RouterID them = itr->second;
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msg.AddAReply(them.ToString());
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}
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else
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msg.AddNXReply();
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}
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}
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else if (msg.questions[0].qtype == dns::qTypeCNAME)
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{
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if (msg.questions[0].IsName("random.snode"))
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{
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RouterID random;
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if (GetRouter()->GetRandomGoodRouter(random))
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msg.AddCNAMEReply(random.ToString(), 1);
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else
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msg.AddNXReply();
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}
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else if (msg.questions[0].IsName("localhost.loki"))
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{
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RouterID us = m_Router->pubkey();
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msg.AddAReply(us.ToString(), 1);
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}
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else
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msg.AddNXReply();
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}
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else if (msg.questions[0].qtype == dns::qTypeA || msg.questions[0].qtype == dns::qTypeAAAA)
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{
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const bool isV6 = msg.questions[0].qtype == dns::qTypeAAAA;
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const bool isV4 = msg.questions[0].qtype == dns::qTypeA;
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if (msg.questions[0].IsName("random.snode"))
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{
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RouterID random;
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if (GetRouter()->GetRandomGoodRouter(random))
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{
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msg.AddCNAMEReply(random.ToString(), 1);
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auto ip = ObtainServiceNodeIP(random);
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msg.AddINReply(ip, false);
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}
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else
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msg.AddNXReply();
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reply(msg);
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return true;
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}
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if (msg.questions[0].IsName("localhost.loki"))
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{
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msg.AddINReply(GetIfAddr(), isV6);
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reply(msg);
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return true;
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}
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// forward dns for snode
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RouterID r;
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if (r.FromString(msg.questions[0].Name()))
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{
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huint128_t ip;
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PubKey pubKey(r);
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if (isV4 && SupportsV6())
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{
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msg.hdr_fields |= dns::flags_QR | dns::flags_AA | dns::flags_RA;
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}
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else if (m_SNodeKeys.find(pubKey) == m_SNodeKeys.end())
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{
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// we do not have it mapped, async obtain it
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ObtainSNodeSession(r, [&](std::shared_ptr<exit::BaseSession> session) {
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if (session && session->IsReady())
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{
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msg.AddINReply(m_KeyToIP[pubKey], isV6);
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}
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else
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{
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msg.AddNXReply();
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}
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reply(msg);
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});
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return true;
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}
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else
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{
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// we have it mapped already as a service node
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auto itr = m_KeyToIP.find(pubKey);
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if (itr != m_KeyToIP.end())
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{
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ip = itr->second;
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msg.AddINReply(ip, isV6);
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}
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else // fallback case that should never happen (probably)
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msg.AddNXReply();
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}
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}
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else
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msg.AddNXReply();
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}
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reply(msg);
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return true;
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}
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void
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ExitEndpoint::ObtainSNodeSession(const RouterID& router, exit::SessionReadyFunc obtainCb)
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{
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ObtainServiceNodeIP(router);
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m_SNodeSessions[router]->AddReadyHook(obtainCb);
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}
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llarp_time_t
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ExitEndpoint::Now() const
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{
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return m_Router->Now();
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}
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bool
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ExitEndpoint::VisitEndpointsFor(
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const PubKey& pk, std::function<bool(exit::Endpoint* const)> visit)
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{
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auto range = m_ActiveExits.equal_range(pk);
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auto itr = range.first;
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while (itr != range.second)
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{
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if (visit(itr->second.get()))
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++itr;
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else
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return true;
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}
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return false;
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}
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void
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ExitEndpoint::Flush()
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{
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m_InetToNetwork.Process([&](Pkt_t& pkt) {
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PubKey pk;
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{
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auto itr = m_IPToKey.find(pkt.dstv6());
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if (itr == m_IPToKey.end())
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{
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// drop
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LogWarn(Name(), " dropping packet, has no session at ", pkt.dstv6());
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return;
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}
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pk = itr->second;
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}
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// check if this key is a service node
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if (m_SNodeKeys.find(pk) != m_SNodeKeys.end())
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{
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// check if it's a service node session we made and queue it via our
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// snode session that we made otherwise use an inbound session that
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// was made by the other service node
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auto itr = m_SNodeSessions.find(pk);
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if (itr != m_SNodeSessions.end())
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{
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if (itr->second->QueueUpstreamTraffic(pkt, routing::ExitPadSize))
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return;
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}
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}
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auto tryFlushingTraffic = [&](exit::Endpoint* const ep) -> bool {
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if (!ep->QueueInboundTraffic(ManagedBuffer{pkt.Buffer()}))
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{
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LogWarn(
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Name(),
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" dropped inbound traffic for session ",
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pk,
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" as we are overloaded (probably)");
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// continue iteration
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return true;
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}
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// break iteration
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return false;
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};
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if (!VisitEndpointsFor(pk, tryFlushingTraffic))
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{
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// we may have all dead sessions, wtf now?
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LogWarn(
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Name(),
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" dropped inbound traffic for session ",
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pk,
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" as we have no working endpoints");
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}
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});
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{
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auto itr = m_ActiveExits.begin();
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while (itr != m_ActiveExits.end())
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{
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if (!itr->second->Flush())
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{
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LogWarn("exit session with ", itr->first, " dropped packets");
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}
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++itr;
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}
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}
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{
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auto itr = m_SNodeSessions.begin();
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while (itr != m_SNodeSessions.end())
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{
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// TODO: move flush upstream to router event loop
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if (!itr->second->FlushUpstream())
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{
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LogWarn("failed to flush snode traffic to ", itr->first, " via outbound session");
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}
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itr->second->FlushDownstream();
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++itr;
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}
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}
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m_Router->PumpLL();
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}
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bool
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ExitEndpoint::Start()
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{
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// map our address
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const PubKey us(m_Router->pubkey());
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const huint128_t ip = GetIfAddr();
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m_KeyToIP[us] = ip;
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m_IPToKey[ip] = us;
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m_IPActivity[ip] = std::numeric_limits<llarp_time_t>::max();
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m_SNodeKeys.insert(us);
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if (m_ShouldInitTun)
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{
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vpn::InterfaceInfo info;
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info.ifname = m_ifname;
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info.addrs.emplace(m_OurRange);
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m_NetIf = GetRouter()->GetVPNPlatform()->ObtainInterface(std::move(info));
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if (not m_NetIf)
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{
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llarp::LogError("Could not create interface");
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return false;
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}
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auto loop = GetRouter()->netloop();
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if (not loop->add_network_interface(
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m_NetIf, [&](net::IPPacket pkt) { OnInetPacket(std::move(pkt)); }))
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{
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llarp::LogWarn("Could not create tunnel for exit endpoint");
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return false;
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}
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loop->add_ticker([&]() { Flush(); });
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llarp::LogInfo("Trying to start resolver ", m_LocalResolverAddr.toString());
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return m_Resolver->Start(m_LocalResolverAddr.createSockAddr(), m_UpstreamResolvers);
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}
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return true;
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}
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AbstractRouter*
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ExitEndpoint::GetRouter()
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{
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return m_Router;
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}
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huint128_t
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ExitEndpoint::GetIfAddr() const
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{
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return m_IfAddr;
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}
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bool
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ExitEndpoint::Stop()
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{
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for (auto& item : m_SNodeSessions)
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item.second->Stop();
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return true;
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}
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bool
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ExitEndpoint::ShouldRemove() const
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{
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for (auto& item : m_SNodeSessions)
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if (!item.second->ShouldRemove())
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return false;
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return true;
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}
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bool
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ExitEndpoint::HasLocalMappedAddrFor(const PubKey& pk) const
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{
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return m_KeyToIP.find(pk) != m_KeyToIP.end();
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}
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huint128_t
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ExitEndpoint::GetIPForIdent(const PubKey pk)
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{
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huint128_t found = {0};
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if (!HasLocalMappedAddrFor(pk))
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{
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// allocate and map
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found.h = AllocateNewAddress().h;
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if (!m_KeyToIP.emplace(pk, found).second)
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{
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LogError(Name(), "failed to map ", pk, " to ", found);
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return found;
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}
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if (!m_IPToKey.emplace(found, pk).second)
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{
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LogError(Name(), "failed to map ", found, " to ", pk);
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return found;
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}
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if (HasLocalMappedAddrFor(pk))
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LogInfo(Name(), " mapping ", pk, " to ", found);
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else
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LogError(Name(), "failed to map ", pk, " to ", found);
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}
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else
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found.h = m_KeyToIP[pk].h;
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MarkIPActive(found);
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m_KeyToIP.rehash(0);
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assert(HasLocalMappedAddrFor(pk));
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return found;
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}
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huint128_t
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ExitEndpoint::AllocateNewAddress()
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{
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if (m_NextAddr < m_HigestAddr)
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return ++m_NextAddr;
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// find oldest activity ip address
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huint128_t found = {0};
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llarp_time_t min = std::numeric_limits<llarp_time_t>::max();
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auto itr = m_IPActivity.begin();
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while (itr != m_IPActivity.end())
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{
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if (itr->second < min)
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{
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found.h = itr->first.h;
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min = itr->second;
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}
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++itr;
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}
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// kick old ident off exit
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// TODO: DoS
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PubKey pk = m_IPToKey[found];
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KickIdentOffExit(pk);
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return found;
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}
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bool
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ExitEndpoint::QueueOutboundTraffic(net::IPPacket pkt)
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{
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return m_NetIf && m_NetIf->WritePacket(std::move(pkt));
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}
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void
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ExitEndpoint::KickIdentOffExit(const PubKey& pk)
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{
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LogInfo(Name(), " kicking ", pk, " off exit");
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huint128_t ip = m_KeyToIP[pk];
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m_KeyToIP.erase(pk);
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m_IPToKey.erase(ip);
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auto range = m_ActiveExits.equal_range(pk);
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auto exit_itr = range.first;
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while (exit_itr != range.second)
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exit_itr = m_ActiveExits.erase(exit_itr);
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}
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void
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ExitEndpoint::MarkIPActive(huint128_t ip)
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{
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m_IPActivity[ip] = GetRouter()->Now();
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}
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void
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ExitEndpoint::OnInetPacket(net::IPPacket pkt)
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{
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m_InetToNetwork.Emplace(std::move(pkt));
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}
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bool
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ExitEndpoint::QueueSNodePacket(const llarp_buffer_t& buf, huint128_t from)
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{
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net::IPPacket pkt;
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if (!pkt.Load(buf))
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return false;
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// rewrite ip
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if (m_UseV6)
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pkt.UpdateIPv6Address(from, m_IfAddr);
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else
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pkt.UpdateIPv4Address(xhtonl(net::TruncateV6(from)), xhtonl(net::TruncateV6(m_IfAddr)));
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return m_NetIf and m_NetIf->WritePacket(std::move(pkt));
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}
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exit::Endpoint*
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ExitEndpoint::FindEndpointByPath(const PathID_t& path)
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{
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exit::Endpoint* endpoint = nullptr;
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PubKey pk;
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{
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auto itr = m_Paths.find(path);
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if (itr == m_Paths.end())
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return nullptr;
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pk = itr->second;
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}
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{
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auto itr = m_ActiveExits.find(pk);
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if (itr != m_ActiveExits.end())
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{
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if (itr->second->PubKey() == pk)
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endpoint = itr->second.get();
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}
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}
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return endpoint;
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}
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bool
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ExitEndpoint::UpdateEndpointPath(const PubKey& remote, const PathID_t& next)
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{
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// check if already mapped
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auto itr = m_Paths.find(next);
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if (itr != m_Paths.end())
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return false;
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m_Paths.emplace(next, remote);
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return true;
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}
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void
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ExitEndpoint::Configure(const NetworkConfig& networkConfig, const DnsConfig& dnsConfig)
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{
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/*
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* TODO: pre-config refactor, this was checking a couple things that were extremely vague
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* these could have appeared on either [dns] or [network], but they weren't documented
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* anywhere
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*
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if (k == "type" && v == "null")
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{
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m_ShouldInitTun = false;
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return true;
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}
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if (k == "exit")
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{
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m_PermitExit = IsTrueValue(v.c_str());
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return true;
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}
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*/
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if (networkConfig.m_endpointType == "null")
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{
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m_ShouldInitTun = false;
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}
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m_LocalResolverAddr = dnsConfig.m_bind;
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m_UpstreamResolvers = dnsConfig.m_upstreamDNS;
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m_OurRange = networkConfig.m_ifaddr;
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if (!m_OurRange.addr.h)
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{
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const auto maybe = llarp::FindFreeRange();
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if (not maybe.has_value())
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throw std::runtime_error("cannot find free interface range");
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m_OurRange = *maybe;
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}
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const auto host_str = m_OurRange.BaseAddressString();
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// string, or just a plain char array?
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m_IfAddr = m_OurRange.addr;
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m_NextAddr = m_IfAddr;
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m_HigestAddr = m_OurRange.HighestAddr();
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m_UseV6 = not m_OurRange.IsV4();
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m_ifname = networkConfig.m_ifname;
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if (m_ifname.empty())
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{
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const auto maybe = llarp::FindFreeTun();
|
|
if (not maybe.has_value())
|
|
throw std::runtime_error("cannot find free interface name");
|
|
m_ifname = *maybe;
|
|
}
|
|
LogInfo(Name(), " set ifname to ", m_ifname);
|
|
|
|
// TODO: "exit-whitelist" and "exit-blacklist"
|
|
// (which weren't originally implemented)
|
|
}
|
|
|
|
huint128_t
|
|
ExitEndpoint::ObtainServiceNodeIP(const RouterID& other)
|
|
{
|
|
const PubKey pubKey(other);
|
|
const PubKey us(m_Router->pubkey());
|
|
// just in case
|
|
if (pubKey == us)
|
|
return m_IfAddr;
|
|
|
|
huint128_t ip = GetIPForIdent(pubKey);
|
|
if (m_SNodeKeys.emplace(pubKey).second)
|
|
{
|
|
auto session = std::make_shared<exit::SNodeSession>(
|
|
other,
|
|
std::bind(&ExitEndpoint::QueueSNodePacket, this, std::placeholders::_1, ip),
|
|
GetRouter(),
|
|
2,
|
|
1,
|
|
true,
|
|
false);
|
|
// this is a new service node make an outbound session to them
|
|
m_SNodeSessions.emplace(other, session);
|
|
}
|
|
return ip;
|
|
}
|
|
|
|
bool
|
|
ExitEndpoint::AllocateNewExit(const PubKey pk, const PathID_t& path, bool wantInternet)
|
|
{
|
|
if (wantInternet && !m_PermitExit)
|
|
return false;
|
|
auto ip = GetIPForIdent(pk);
|
|
if (GetRouter()->pathContext().TransitHopPreviousIsRouter(path, pk.as_array()))
|
|
{
|
|
// we think this path belongs to a service node
|
|
// mark it as such so we don't make an outbound session to them
|
|
m_SNodeKeys.emplace(pk.as_array());
|
|
}
|
|
m_ActiveExits.emplace(
|
|
pk, std::make_unique<exit::Endpoint>(pk, path, !wantInternet, ip, this));
|
|
|
|
m_Paths[path] = pk;
|
|
|
|
return HasLocalMappedAddrFor(pk);
|
|
}
|
|
|
|
std::string
|
|
ExitEndpoint::Name() const
|
|
{
|
|
return m_Name;
|
|
}
|
|
|
|
void
|
|
ExitEndpoint::DelEndpointInfo(const PathID_t& path)
|
|
{
|
|
m_Paths.erase(path);
|
|
}
|
|
|
|
void
|
|
ExitEndpoint::RemoveExit(const exit::Endpoint* ep)
|
|
{
|
|
auto range = m_ActiveExits.equal_range(ep->PubKey());
|
|
auto itr = range.first;
|
|
while (itr != range.second)
|
|
{
|
|
if (itr->second->LocalPath() == ep->LocalPath())
|
|
{
|
|
itr = m_ActiveExits.erase(itr);
|
|
// now ep is gone af
|
|
return;
|
|
}
|
|
++itr;
|
|
}
|
|
}
|
|
|
|
void
|
|
ExitEndpoint::Tick(llarp_time_t now)
|
|
{
|
|
{
|
|
auto itr = m_SNodeSessions.begin();
|
|
while (itr != m_SNodeSessions.end())
|
|
{
|
|
if (itr->second->IsExpired(now))
|
|
itr = m_SNodeSessions.erase(itr);
|
|
else
|
|
{
|
|
itr->second->Tick(now);
|
|
++itr;
|
|
}
|
|
}
|
|
}
|
|
{
|
|
// expire
|
|
auto itr = m_ActiveExits.begin();
|
|
while (itr != m_ActiveExits.end())
|
|
{
|
|
if (itr->second->IsExpired(now))
|
|
itr = m_ActiveExits.erase(itr);
|
|
else
|
|
++itr;
|
|
}
|
|
// pick chosen exits and tick
|
|
m_ChosenExits.clear();
|
|
itr = m_ActiveExits.begin();
|
|
while (itr != m_ActiveExits.end())
|
|
{
|
|
// do we have an exit set for this key?
|
|
if (m_ChosenExits.find(itr->first) != m_ChosenExits.end())
|
|
{
|
|
// yes
|
|
if (m_ChosenExits[itr->first]->createdAt < itr->second->createdAt)
|
|
{
|
|
// if the iterators's exit is newer use it for the chosen exit for
|
|
// key
|
|
if (!itr->second->LooksDead(now))
|
|
m_ChosenExits[itr->first] = itr->second.get();
|
|
}
|
|
}
|
|
else if (!itr->second->LooksDead(now)) // set chosen exit if not dead for key that
|
|
// doesn't have one yet
|
|
m_ChosenExits[itr->first] = itr->second.get();
|
|
// tick which clears the tx rx counters
|
|
itr->second->Tick(now);
|
|
++itr;
|
|
}
|
|
}
|
|
}
|
|
} // namespace handlers
|
|
} // namespace llarp
|