mirror of
https://github.com/oxen-io/lokinet.git
synced 2024-10-29 11:05:43 +00:00
609 lines
16 KiB
C++
609 lines
16 KiB
C++
#include <handlers/exit.hpp>
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#include <net.hpp>
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#include <router.hpp>
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#include <str.hpp>
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#include <dns/dns.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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static void
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ExitHandlerRecvPkt(llarp_tun_io *tun, llarp_buffer_t buf)
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{
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static_cast< ExitEndpoint * >(tun->user)->OnInetPacket(buf);
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}
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static void
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ExitHandlerFlush(llarp_tun_io *tun)
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{
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static_cast< ExitEndpoint * >(tun->user)->Flush();
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}
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ExitEndpoint::ExitEndpoint(const std::string &name, llarp::Router *r)
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: m_Router(r)
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, m_Resolver(r->netloop, this)
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, m_Name(name)
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, m_Tun{{0}, 0, {0}, 0, 0, 0, 0, 0, 0, 0}
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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_Tun.user = this;
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m_Tun.recvpkt = &ExitHandlerRecvPkt;
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m_Tun.tick = &ExitHandlerFlush;
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m_ShouldInitTun = true;
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}
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ExitEndpoint::~ExitEndpoint()
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{
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}
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bool
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ExitEndpoint::ShouldHookDNSMessage(const llarp::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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if(msg.questions[0].qtype == llarp::dns::qTypePTR)
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{
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llarp::huint32_t ip;
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if(!llarp::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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else if(msg.questions[0].qtype == llarp::dns::qTypeA)
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{
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return msg.questions[0].qname.find(".snode.")
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== (msg.questions[0].qname.size() - 7);
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}
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else
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return false;
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}
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bool
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ExitEndpoint::HandleHookedDNSMessage(
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llarp::dns::Message msg,
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std::function< void(llarp::dns::Message) > reply)
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{
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if(msg.questions[0].qtype == llarp::dns::qTypePTR)
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{
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llarp::huint32_t ip;
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if(!llarp::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 = Router()->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()
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&& 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 == llarp::dns::qTypeA)
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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].qname))
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{
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huint32_t ip;
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PubKey pubKey(r);
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if(m_SNodeKeys.find(pubKey) == m_SNodeKeys.end())
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{
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// we do not have it mapped
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// map it
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ip = ObtainServiceNodeIP(r);
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msg.AddINReply(ip);
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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);
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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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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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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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llarp::PubKey pk;
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{
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auto itr = m_IPToKey.find(pkt.dst());
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if(itr == m_IPToKey.end())
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{
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// drop
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llarp::LogWarn(Name(), " dropping packet, has no session at ",
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pkt.dst());
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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,
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llarp::routing::ExitPadSize))
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return;
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}
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}
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llarp::exit::Endpoint *ep = m_ChosenExits[pk];
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if(ep == nullptr)
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{
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// we may have all dead sessions, wtf now?
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llarp::LogWarn(Name(), " dropped inbound traffic for session ", pk,
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" as we have no working endpoints");
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}
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else
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{
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if(!ep->QueueInboundTraffic(pkt.Buffer()))
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{
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llarp::LogWarn(Name(), " dropped inbound traffic for session ", pk,
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" as we are overloaded (probably)");
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}
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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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llarp::LogWarn("exit session with ", itr->first,
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" 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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if(!itr->second->Flush())
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{
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llarp::LogWarn("failed to flush snode traffic to ", itr->first,
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" via outbound session");
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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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bool
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ExitEndpoint::Start()
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{
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if(m_ShouldInitTun)
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{
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if(!llarp_ev_add_tun(Router()->netloop, &m_Tun))
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return false;
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if(m_UpstreamResolvers.size() == 0)
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m_UpstreamResolvers.emplace_back("8.8.8.8", 53);
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return m_Resolver.Start(m_LocalResolverAddr, m_UpstreamResolvers);
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}
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return true;
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}
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llarp::Router *
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ExitEndpoint::Router()
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{
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return m_Router;
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}
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llarp::Crypto *
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ExitEndpoint::Crypto()
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{
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return &m_Router->crypto;
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}
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huint32_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 llarp::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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huint32_t
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ExitEndpoint::GetIPForIdent(const llarp::PubKey pk)
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{
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huint32_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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llarp::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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llarp::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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llarp::LogInfo(Name(), " mapping ", pk, " to ", found);
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else
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llarp::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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huint32_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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huint32_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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llarp::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(llarp_buffer_t buf)
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{
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return llarp_ev_tun_async_write(&m_Tun, buf);
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}
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void
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ExitEndpoint::KickIdentOffExit(const llarp::PubKey &pk)
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{
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llarp::LogInfo(Name(), " kicking ", pk, " off exit");
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huint32_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(llarp::huint32_t ip)
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{
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m_IPActivity[ip] = Router()->Now();
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}
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void
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ExitEndpoint::OnInetPacket(llarp_buffer_t buf)
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{
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m_InetToNetwork.EmplaceIf(
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[buf](Pkt_t &pkt) -> bool { return pkt.Load(buf); });
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}
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bool
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ExitEndpoint::QueueSNodePacket(llarp_buffer_t buf, llarp::huint32_t from)
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{
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llarp::net::IPv4Packet 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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pkt.UpdateIPv4PacketOnDst(from, m_IfAddr);
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return llarp_ev_tun_async_write(&m_Tun, pkt.Buffer());
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}
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llarp::exit::Endpoint *
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ExitEndpoint::FindEndpointByPath(const llarp::PathID_t &path)
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{
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llarp::exit::Endpoint *endpoint = nullptr;
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llarp::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 llarp::PubKey &remote,
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const llarp::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.insert(std::make_pair(next, remote));
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return true;
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}
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bool
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ExitEndpoint::SetOption(const std::string &k, const std::string &v)
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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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if(k == "local-dns")
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{
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std::string resolverAddr = v;
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uint16_t dnsport = 53;
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auto pos = v.find(":");
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if(pos != std::string::npos)
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{
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resolverAddr = v.substr(0, pos);
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dnsport = std::atoi(v.substr(pos + 1).c_str());
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}
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m_LocalResolverAddr = llarp::Addr(resolverAddr, dnsport);
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llarp::LogInfo(Name(), " local dns set to ", m_LocalResolverAddr);
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}
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if(k == "upstream-dns")
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{
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std::string resolverAddr = v;
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uint16_t dnsport = 53;
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auto pos = v.find(":");
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if(pos != std::string::npos)
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{
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resolverAddr = v.substr(0, pos);
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dnsport = std::atoi(v.substr(pos + 1).c_str());
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}
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m_UpstreamResolvers.emplace_back(resolverAddr, dnsport);
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llarp::LogInfo(Name(), " adding upstream dns set to ", resolverAddr,
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":", dnsport);
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}
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if(k == "ifaddr")
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{
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auto pos = v.find("/");
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if(pos == std::string::npos)
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{
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llarp::LogError(Name(), " ifaddr is not a cidr: ", v);
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return false;
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}
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std::string nmask_str = v.substr(1 + pos);
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std::string host_str = v.substr(0, pos);
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// string, or just a plain char array?
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strncpy(m_Tun.ifaddr, host_str.c_str(), sizeof(m_Tun.ifaddr) - 1);
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m_Tun.netmask = std::atoi(nmask_str.c_str());
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llarp::Addr ifaddr(host_str);
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m_IfAddr = ifaddr.xtohl();
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m_OurRange.netmask_bits = netmask_ipv4_bits(m_Tun.netmask);
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m_OurRange.addr = m_IfAddr;
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m_NextAddr = m_IfAddr;
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m_HigestAddr = m_IfAddr | (~m_OurRange.netmask_bits);
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llarp::LogInfo(Name(), " set ifaddr range to ", m_Tun.ifaddr, "/",
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m_Tun.netmask, " lo=", m_IfAddr, " hi=", m_HigestAddr);
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}
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if(k == "ifname")
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{
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if(v.length() >= sizeof(m_Tun.ifname))
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{
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llarp::LogError(Name() + " ifname '", v, "' is too long");
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return false;
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}
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strncpy(m_Tun.ifname, v.c_str(), sizeof(m_Tun.ifname) - 1);
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llarp::LogInfo(Name(), " set ifname to ", m_Tun.ifname);
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}
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if(k == "exit-whitelist")
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{
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// add exit policy whitelist rule
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// TODO: implement me
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return true;
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}
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if(k == "exit-blacklist")
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{
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// add exit policy blacklist rule
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// TODO: implement me
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return true;
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}
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return true;
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}
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huint32_t
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ExitEndpoint::ObtainServiceNodeIP(const llarp::RouterID &other)
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{
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PubKey pubKey(other);
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huint32_t ip = GetIPForIdent(pubKey);
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if(m_SNodeKeys.emplace(pubKey).second)
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{
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// this is a new service node make an outbound session to them
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m_SNodeSessions.emplace(
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other,
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std::unique_ptr< llarp::exit::SNodeSession >(
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new llarp::exit::SNodeSession(
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other,
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std::bind(&ExitEndpoint::QueueSNodePacket, this,
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std::placeholders::_1, ip),
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Router(), 2, 1, true)));
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}
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return ip;
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}
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bool
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ExitEndpoint::AllocateNewExit(const llarp::PubKey pk,
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const llarp::PathID_t &path,
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bool wantInternet)
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{
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if(wantInternet && !m_PermitExit)
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return false;
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huint32_t ip = GetIPForIdent(pk);
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if(Router()->paths.TransitHopPreviousIsRouter(path, pk.as_array()))
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{
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// we think this path belongs to a service node
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// mark it as such so we don't make an outbound session to them
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m_SNodeKeys.emplace(pk.as_array());
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}
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m_ActiveExits.emplace(pk,
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std::make_unique< llarp::exit::Endpoint >(
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pk, path, !wantInternet, ip, this));
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m_Paths[path] = pk;
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return HasLocalMappedAddrFor(pk);
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}
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std::string
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ExitEndpoint::Name() const
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{
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return m_Name;
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}
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void
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ExitEndpoint::DelEndpointInfo(const llarp::PathID_t &path)
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{
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m_Paths.erase(path);
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}
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void
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ExitEndpoint::RemoveExit(const llarp::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;
|
|
}
|
|
}
|
|
{
|
|
// 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
|