Commit e717c2cb authored by jan.koester's avatar jan.koester
Browse files

Add accept() debug logging for QUIC remote diagnosis

parent 9bd1a4e2

debian/changelog

+6 −0
Original line number Diff line number Diff line 
libnetplus (20260424+19) unstable; urgency=medium



  * Add accept() debug logging for QUIC remote connection diagnosis



 -- Jan Koester <jan.koester@tuxist.de>  Thu, 24 Apr 2026 16:15:00 +0200



libnetplus (20260424+18) unstable; urgency=medium



  * Enable QUIC debug logging for HTTP/3 handshake diagnosis

src/quic.cpp

+24 −0
Original line number Diff line number Diff line
@@ -1190,6 +1190,22 @@ void quic::accept(std::unique_ptr<socket>& csock, bool nonblock) { 
    

    dgram.resize(static_cast<size_t>(recv_len));



    {

        char peer_ip_dbg[INET6_ADDRSTRLEN] = {};

        uint16_t peer_port_dbg = 0;

        if (peer_addr.ss_family == AF_INET) {

            auto* sa4 = reinterpret_cast<struct sockaddr_in*>(&peer_addr);

            inet_ntop(AF_INET, &sa4->sin_addr, peer_ip_dbg, sizeof(peer_ip_dbg));

            peer_port_dbg = ntohs(sa4->sin_port);

        } else if (peer_addr.ss_family == AF_INET6) {

            auto* sa6 = reinterpret_cast<struct sockaddr_in6*>(&peer_addr);

            inet_ntop(AF_INET6, &sa6->sin6_addr, peer_ip_dbg, sizeof(peer_ip_dbg));

            peer_port_dbg = ntohs(sa6->sin6_port);

        }

        QUIC_DBG("accept: recv %zd bytes from %s:%u first_byte=0x%02x _Socket=%d",

                 recv_len, peer_ip_dbg, peer_port_dbg, dgram[0], _Socket);

    }

    

    // Check if this is a long header packet (Initial, Handshake, etc.)

    if ((dgram[0] & 0x80) == 0) {

        // Short header - this is for an existing connection
@@ -1257,8 +1273,11 @@ void quic::accept(std::unique_ptr<socket>& csock, bool nonblock) { 
                       (static_cast<uint32_t>(dgram[3]) << 8) |

                       static_cast<uint32_t>(dgram[4]);

    

    QUIC_DBG("accept: long header version=0x%08x", version);



    // Check for version negotiation (version == 0 means VN)

    if (version == 0) {

        QUIC_DBG("accept: skipping VN packet");

        continue;  // Skip VN packets

    }
@@ -1350,9 +1369,11 @@ void quic::accept(std::unique_ptr<socket>& csock, bool nonblock) { 
    // Check packet type - must be Initial (0x00) for new connections

    uint8_t packet_type = (dgram[0] & 0x30) >> 4;

    if (packet_type != 0x00) {

        QUIC_DBG("accept: not Initial pkt_type=%u for unknown CID, dropping", packet_type);

        // Not an Initial packet and no existing connection found - skip

        continue;

    }

    QUIC_DBG("accept: NEW Initial from remote, creating child connection");

    

    {

        char peer_ip[INET6_ADDRSTRLEN] = {};
@@ -1370,10 +1391,13 @@ void quic::accept(std::unique_ptr<socket>& csock, bool nonblock) { 
    

    // Verify supported version

    if (version != QUIC_VERSION_1 && version != QUIC_VERSION_2) {

        QUIC_DBG("accept: UNSUPPORTED version 0x%08x, dropping", version);

        // Send Version Negotiation packet

        // TODO: Implement version negotiation

        continue;

    }

    QUIC_DBG("accept: version OK, dcid_len=%u scid_len=%u pkt_type=%u",

             dcid_len, scid_len, (dgram[0] & 0x30) >> 4);

    

    // Parse token (for Initial packets)

    if (offset >= dgram.size()) {