3 files changed, 162 insertions, 0 deletions
diff --git a/gr-digital/lib/CMakeLists.txt b/gr-digital/lib/CMakeLists.txt
index 9a39a85267..ceee1adb9b 100644
--- a/gr-digital/lib/CMakeLists.txt
+++ b/gr-digital/lib/CMakeLists.txt
@@ -30,6 +30,7 @@ add_library(gnuradio-digital
     correlate_access_code_ff_ts_impl.cc
     costas_loop_cc_impl.cc
     cpmmod_bc_impl.cc
+    crc16_async_bb_impl.cc
     crc32_bb_impl.cc
     crc32_async_bb_impl.cc
     decision_feedback_equalizer_impl.cc
diff --git a/gr-digital/lib/crc16_async_bb_impl.cc b/gr-digital/lib/crc16_async_bb_impl.cc
new file mode 100644
index 0000000000..05f5f96695
--- /dev/null
+++ b/gr-digital/lib/crc16_async_bb_impl.cc
@@ -0,0 +1,113 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2021 Cesar Martinez.
+ *
+ * This file is part of GNU Radio
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "crc16_async_bb_impl.h"
+#include <gnuradio/io_signature.h>
+#include <volk/volk.h>
+
+namespace gr {
+namespace digital {
+
+crc16_async_bb::sptr crc16_async_bb::make(bool check)
+{
+    return gnuradio::make_block_sptr<crc16_async_bb_impl>(check);
+}
+
+crc16_async_bb_impl::crc16_async_bb_impl(bool check)
+    : block("crc16_async_bb", io_signature::make(0, 0, 0), io_signature::make(0, 0, 0)),
+      d_npass(0),
+      d_nfail(0)
+{
+    d_in_port = pmt::mp("in");
+    d_out_port = pmt::mp("out");
+
+    message_port_register_in(d_in_port);
+    message_port_register_out(d_out_port);
+
+    if (check)
+        set_msg_handler(d_in_port, [this](pmt::pmt_t msg) { this->check(msg); });
+    else
+        set_msg_handler(d_in_port, [this](pmt::pmt_t msg) { this->calc(msg); });
+}
+
+crc16_async_bb_impl::~crc16_async_bb_impl() {}
+
+void crc16_async_bb_impl::calc(pmt::pmt_t msg)
+{
+    // extract input pdu
+    pmt::pmt_t meta(pmt::car(msg));
+    pmt::pmt_t bytes(pmt::cdr(msg));
+
+    unsigned int crc;
+    size_t pkt_len(0);
+    const uint8_t* bytes_in = pmt::u8vector_elements(bytes, pkt_len);
+    std::vector<uint8_t> bytes_out(2 + pkt_len);
+
+    crc = process_crc(bytes_in, pkt_len);
+
+    memcpy((void*)bytes_out.data(), (const void*)bytes_in, pkt_len);
+    memcpy((void*)(bytes_out.data() + pkt_len), &crc, 2);
+
+    pmt::pmt_t output = pmt::init_u8vector(
+        pkt_len + 2,
+        bytes_out.data()); // this copies the values from bytes_out into the u8vector
+    pmt::pmt_t msg_pair = pmt::cons(meta, output);
+    message_port_pub(d_out_port, msg_pair);
+}
+
+unsigned int crc16_async_bb_impl::process_crc(const uint8_t* bytes_in,
+                                              size_t n_bytes_prcss)
+{
+
+    unsigned int result;
+
+    d_crc_ccitt_impl.reset();
+    d_crc_ccitt_impl.process_bytes(bytes_in, n_bytes_prcss);
+    result = d_crc_ccitt_impl();
+    return result;
+}
+
+void crc16_async_bb_impl::check(pmt::pmt_t msg)
+{
+    // extract input pdu
+    pmt::pmt_t meta(pmt::car(msg));
+    pmt::pmt_t bytes(pmt::cdr(msg));
+
+    unsigned int crc;
+    size_t pkt_len(0);
+    const uint8_t* bytes_in = pmt::u8vector_elements(bytes, pkt_len);
+
+    crc = process_crc(bytes_in, pkt_len - 2);
+
+    if (crc != *(unsigned int*)(bytes_in + pkt_len - 2)) { // Drop package
+        d_nfail++;
+        return;
+    }
+    d_npass++;
+
+    pmt::pmt_t output = pmt::init_u8vector(pkt_len - 2, bytes_in);
+    pmt::pmt_t msg_pair = pmt::cons(meta, output);
+    message_port_pub(d_out_port, msg_pair);
+}
+
+int crc16_async_bb_impl::general_work(int noutput_items,
+                                      gr_vector_int& ninput_items,
+                                      gr_vector_const_void_star& input_items,
+                                      gr_vector_void_star& output_items)
+{
+    return noutput_items;
+}
+
+} /* namespace digital */
+} /* namespace gr */
diff --git a/gr-digital/lib/crc16_async_bb_impl.h b/gr-digital/lib/crc16_async_bb_impl.h
new file mode 100644
index 0000000000..9e65164021
--- /dev/null
+++ b/gr-digital/lib/crc16_async_bb_impl.h
@@ -0,0 +1,48 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2021 Cesar Martinez.
+ *
+ * This file is part of GNU Radio
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ */
+
+#ifndef INCLUDED_DIGITAL_CRC16_ASYNC_BB_IMPL_H
+#define INCLUDED_DIGITAL_CRC16_ASYNC_BB_IMPL_H
+
+#include <gnuradio/digital/crc16_async_bb.h>
+#include <boost/crc.hpp>
+
+namespace gr {
+namespace digital {
+
+class crc16_async_bb_impl : public crc16_async_bb
+{
+private:
+    boost::crc_ccitt_type d_crc_ccitt_impl;
+
+    pmt::pmt_t d_in_port;
+    pmt::pmt_t d_out_port;
+
+    unsigned int process_crc(const uint8_t* bytes_in, size_t n_bytes_prcss);
+    void calc(pmt::pmt_t msg);
+    void check(pmt::pmt_t msg);
+
+public:
+    crc16_async_bb_impl(bool check);
+    ~crc16_async_bb_impl() override;
+
+    int general_work(int noutput_items,
+                     gr_vector_int& ninput_items,
+                     gr_vector_const_void_star& input_items,
+                     gr_vector_void_star& output_items) override;
+
+    uint64_t d_npass;
+    uint64_t d_nfail;
+};
+
+} // namespace digital
+} // namespace gr
+
+#endif /* INCLUDED_DIGITAL_crc16_ASYNC_BB_IMPL_H */