struct tcp_flow_control {
    uint32_t cwnd;          // Congestion window
    uint32_t rwnd;          // Receiver window
    uint32_t ssthresh;      // Slow start threshold
    uint32_t mss;           // Maximum segment size
};

void adjust_window_size(struct tcp_flow_control *fc, uint32_t ack_received) {
    if (fc->cwnd < fc->ssthresh) {
        // Slow start phase
        fc->cwnd += fc->mss;
    } else {
        // Congestion avoidance
        fc->cwnd += (fc->mss * fc->mss) / fc->cwnd;
    }
    // Ensure we don't exceed receiver's window
    fc->cwnd = MIN(fc->cwnd, fc->rwnd);
}

struct http3_stream {
    uint64_t stream_id;
    uint8_t stream_state;
    circular_buffer_t *recv_buffer;
    priority_queue_t *send_queue;
    quic_connection_t *quic_conn;
};

int http3_handle_stream_data(struct http3_stream *stream) {
    frame_header_t frame;
    while (stream->recv_buffer->size > 0) {
        if (parse_frame_header(stream->recv_buffer, &frame) != 0) {
            return H3_ERR_FRAME_ERROR;
        }
        
        switch (frame.type) {
            case H3_FRAME_HEADERS:
                process_headers(stream, frame);
                break;
            case H3_FRAME_DATA:
                process_data(stream, frame);
                break;
            case H3_FRAME_PUSH_PROMISE:
                handle_push_promise(stream, frame);
                break;
        }
    }
    return H3_SUCCESS;
}

struct mqtt_session {
    uint16_t client_id;
    uint8_t protocol_version;
    bool clean_start;
    uint32_t session_expiry;
    hash_table_t *pending_acks;
};

int handle_publish_packet(struct mqtt_session *session, 
                         mqtt_packet_t *packet) {
    switch (packet->qos) {
        case MQTT_QOS_0:
            return deliver_immediately(packet);
            
        case MQTT_QOS_1:
            store_message(session, packet);
            send_puback(session, packet->packet_id);
            return deliver_with_retry(session, packet);
            
        case MQTT_QOS_2:
            store_message(session, packet);
            add_to_pending(session->pending_acks, packet);
            return send_pubrec(session, packet->packet_id);
    }
}

struct bgp_path_attributes {
    uint32_t local_pref;
    uint32_t med;
    uint8_t origin;
    uint32_t *as_path;
    size_t as_path_length;
    uint32_t next_hop;
    bool atomic_aggregate;
};

int compare_paths(const struct bgp_path_attributes *path1,
                 const struct bgp_path_attributes *path2) {
    // Compare LOCAL_PREF (higher is better)
    if (path1->local_pref != path2->local_pref)
        return path1->local_pref > path2->local_pref ? 1 : -1;
    
    // Compare AS_PATH length (shorter is better)
    if (path1->as_path_length != path2->as_path_length)
        return path1->as_path_length < path2->as_path_length ? 1 : -1;
        
    // Compare origin (IGP > EGP > Incomplete)
    if (path1->origin != path2->origin)
        return compare_origin(path1->origin, path2->origin);
        
    // Compare MED (lower is better)
    return path2->med - path1->med;
}

struct ws_security_context {
    SSL *ssl;
    uint8_t *session_key;
    size_t key_length;
    rate_limiter_t *limiter;
    uint64_t last_ping_time;
};

int secure_ws_frame(struct ws_security_context *ctx, 
                    ws_frame_t *frame) {
    if (!check_rate_limit(ctx->limiter)) {
        return WS_ERR_RATE_LIMIT;
    }

    // Generate frame mask
    uint8_t mask[4];
    generate_secure_mask(ctx->ssl, mask);
    
    // Apply encryption
    uint8_t *payload = frame->payload;
    size_t length = frame->length;
    
    for (size_t i = 0; i < length; i++) {
        payload[i] ^= mask[i % 4];
        payload[i] ^= ctx->session_key[i % ctx->key_length];
    }
    
    return WS_SUCCESS;
}