lokinet/include/llarp/dht/context.hpp

#ifndef LLARP_DHT_CONTEXT_HPP
#define LLARP_DHT_CONTEXT_HPP

#include <llarp/dht.h>
#include <llarp/router.h>
#include <llarp/dht/bucket.hpp>
#include <llarp/dht/key.hpp>
#include <llarp/dht/message.hpp>
#include <llarp/dht/messages/findintro.hpp>
#include <llarp/dht/node.hpp>
#include <llarp/dht/search_job.hpp>
#include <llarp/service/IntroSet.hpp>

#include <set>

namespace llarp
{
  namespace dht
  {
    struct Context
    {
      Context();
      ~Context();

      SearchJob*
      FindPendingTX(const Key_t& owner, uint64_t txid);

      void
      RemovePendingTX(const Key_t& owner, uint64_t txid);

      void
      LookupServiceDirect(const Key_t& target, const Key_t& whoasked,
                          uint64_t whoaskedTX, const Key_t& askpeer,
                          SearchJob::IntroSetHookFunc handler,
                          bool iterateive            = false,
                          std::set< Key_t > excludes = {});

      void
      LookupRouter(const Key_t& target, const Key_t& whoasked,
                   uint64_t whoaskedTX, const Key_t& askpeer,
                   llarp_router_lookup_job* job = nullptr,
                   bool iterative = false, std::set< Key_t > excludes = {});

      void
      LookupIntroSet(const service::Address& addr, const Key_t& whoasked,
                     uint64_t whoaskedTX, const Key_t& askpeer, uint64_t R,
                     std::set< Key_t > excludes = {});

      void
      LookupTag(const service::Tag& tag, const Key_t& whoasked,
                uint64_t whoaskedTX, const Key_t& askpeer,
                const std::set< service::IntroSet >& include = {},
                uint64_t R                                   = 0);
      void
      LookupRouterViaJob(llarp_router_lookup_job* job);

      void
      LookupTagForPath(const service::Tag& tag, uint64_t txid,
                       const llarp::PathID_t& path, const Key_t& askpeer);

      void
      LookupIntroSetForPath(const service::Address& addr, uint64_t txid,
                            const llarp::PathID_t& path, Key_t askpeer);

      template < typename Job, typename Result >
      bool
      TryLookupAgain(Job* j, Result r, uint64_t R)
      {
        const Key_t targetKey = j->target.ToKey();
        Key_t askpeer;
        std::set< Key_t > exclude = j->asked;
        if(!nodes->FindCloseExcluding(targetKey, askpeer, exclude))
        {
          j->Exausted();
          return true;
        }
        if((OurKey() ^ targetKey) < (askpeer ^ targetKey))
        {
          j->Exausted();
          return true;
        }
        auto id = ++ids;
        TXOwner ownerKey;
        ownerKey.node = askpeer;
        ownerKey.txid = id;
        SearchJob job(j->whoasked, j->txid, r, [j]() { delete j; });
        pendingTX[ownerKey] = job;
        auto msg            = new FindIntroMessage(id, j->target);
        msg->R              = R;
        llarp::LogInfo("asking ", askpeer, " for ", j->target.ToString(),
                       " with txid=", id);
        DHTSendTo(askpeer, msg);
        j->asked.insert(std::move(askpeer));
        return false;
      }

      void
      DHTSendTo(const Key_t& peer, IMessage* msg);

      bool
      LookupRouterExploritory(const Key_t& requester, uint64_t txid,
                              const RouterID& target,
                              std::vector< IMessage* >& reply);

      void
      LookupIntroSetRelayed(const Key_t& requester, uint64_t txid,
                            const service::Address& addr, bool recursive,
                            std::vector< IMessage* >& reply);

      std::set< service::IntroSet >
      FindRandomIntroSetsWithTag(const service::Tag& tag, size_t max = 2);

      void
      LookupRouterRelayed(const Key_t& requester, uint64_t txid,
                          const Key_t& target, bool recursive,
                          std::vector< IMessage* >& replies);

      bool
      RelayRequestForPath(const llarp::PathID_t& localPath,
                          const IMessage* msg);

      void
      PropagateIntroSetTo(const Key_t& from, uint64_t fromTX,
                          const service::IntroSet& introset, const Key_t& peer,
                          uint64_t S, const std::set< Key_t >& exclude);

      void
      Init(const Key_t& us, llarp_router* router, llarp_time_t exploreInterval);

      const llarp::service::IntroSet*
      GetIntroSetByServiceAddress(const llarp::service::Address& addr) const;

      void
      QueueRouterLookup(llarp_router_lookup_job* job);

      static void
      handle_cleaner_timer(void* user, uint64_t orig, uint64_t left);

      static void
      handle_explore_timer(void* user, uint64_t orig, uint64_t left);

      /// explore dht for new routers
      void
      Explore();

      static void
      queue_router_lookup(void* user);

      llarp_router* router = nullptr;
      // for router contacts
      Bucket< RCNode >* nodes = nullptr;

      // for introduction sets
      Bucket< ISNode >* services = nullptr;
      bool allowTransit          = false;

      const Key_t&
      OurKey() const
      {
        return ourKey;
      }

     private:
      void
      ScheduleCleanupTimer();

      void
      HandleExploreResult(const std::vector< RouterID >& result);

      void
      CleanupTX();

      uint64_t ids;

      struct TXOwner
      {
        Key_t node;
        uint64_t txid = 0;

        bool
        operator==(const TXOwner& other) const
        {
          return txid == other.txid && node == other.node;
        }
        bool
        operator<(const TXOwner& other) const
        {
          return txid < other.txid || node < other.node;
        }
      };

      struct TXOwnerHash
      {
        std::size_t
        operator()(TXOwner const& o) const noexcept
        {
          std::size_t sz2;
          memcpy(&sz2, &o.node[0], sizeof(std::size_t));
          return o.txid ^ (sz2 << 1);
        }
      };  // namespace dht

      std::unordered_map< TXOwner, SearchJob, TXOwnerHash > pendingTX;
      Key_t ourKey;
    };  // namespace llarp
  }     // namespace dht
}  // namespace llarp

struct llarp_dht_context
{
  llarp::dht::Context impl;
  llarp_router* parent;
  llarp_dht_context(llarp_router* router);
};

#endif