limen/eth/eth.cpp

#include "eth.h"
#include <array>
#include "pico/unique_id.h"
#include "parse_buffer.h"
#include "prepend_buffer.h"
#include "w6300.h"
#include "debug_log.h"

namespace eth {

namespace {

mac_addr g_mac;
w6300::socket_id raw_socket{0};
frame_cb_list frame_callbacks;

struct ethertype_entry {
    uint16_t ethertype_be;
    ethertype_handler fn;
};
std::array<ethertype_entry, 8> eth_handlers;
size_t eth_handler_count = 0;

std::array<mac_filter, 4> mac_filters;
size_t mac_filter_count = 0;

bool default_mac_filter(const mac_addr& dst) {
    return dst == g_mac || dst == MAC_BROADCAST;
}

bool mac_match(const mac_addr& dst) {
    for (size_t i = 0; i < mac_filter_count; i++) {
        if (mac_filters[i](dst)) {
            return true;
        }
    }
    return false;
}

void process_frame(std::span<const uint8_t> frame, span_writer& tx) {
    if (frame.size() < sizeof(header)) {
        return;
    }
    auto& eth_hdr = *reinterpret_cast<const header*>(frame.data());

    if (!mac_match(eth_hdr.dst)) {
        return;
    }

    frame_callbacks.for_each([&](frame_cb_list::node* n) {
        if (n->value(frame)) {
            frame_callbacks.remove(n);
        }
    });

    for (size_t i = 0; i < eth_handler_count; i++) {
        if (eth_handlers[i].ethertype_be == eth_hdr.ethertype) {
            eth_handlers[i].fn(frame, tx);
            break;
        }
    }
}

} // namespace

void register_ethertype(uint16_t ethertype_be, ethertype_handler fn) {
    if (eth_handler_count >= eth_handlers.size()) {
        dlogf("eth::register_ethertype overflow: ethertype=0x%04x dropped", __builtin_bswap16(ethertype_be));
        return;
    }
    eth_handlers[eth_handler_count++] = {ethertype_be, fn};
}

void register_mac_filter(mac_filter fn) {
    if (mac_filter_count >= mac_filters.size()) {
        dlog("eth::register_mac_filter overflow: filter dropped");
        return;
    }
    mac_filters[mac_filter_count++] = fn;
}

void send_raw(std::span<const uint8_t> data) {
    dlog_if_slow("eth::send_raw", 1000, [&]{
        auto result = w6300::send(raw_socket, data);
        if (!result) {
            dlogf("w6300 send failed: %zu bytes, err %d",
                  data.size(), static_cast<int>(result.error()));
        }
    });
}

bool init() {
    w6300::init_spi();
    w6300::reset();
    w6300::init();
    if (!w6300::check()) {
        return false;
    }

    pico_unique_board_id_t uid;
    pico_get_unique_board_id(&uid);
    g_mac[0] = (uid.id[0] & 0xFC) | 0x02;
    g_mac[1] = uid.id[1];
    g_mac[2] = uid.id[2];
    g_mac[3] = uid.id[3];
    g_mac[4] = uid.id[4];
    g_mac[5] = uid.id[5];

    w6300::open_socket(raw_socket, w6300::protocol::macraw, w6300::sock_flag::none);
    w6300::set_interrupt_mask(w6300::ik_sock_0);

    register_mac_filter(default_mac_filter);

    return true;
}

const mac_addr& get_mac() {
    return g_mac;
}

frame_cb_handle add_frame_callback(frame_callback cb) {
    auto h = frame_callbacks.insert(cb);
    if (!h) {
        dlog("eth::add_frame_callback overflow: callback dropped");
    }
    return h;
}

void remove_frame_callback(frame_cb_handle h) {
    frame_callbacks.remove(h);
}

void poll(std::span<uint8_t> tx) {
    if (!w6300::irq_pending) {
        return;
    }
    w6300::irq_pending = false;
    w6300::clear_interrupt(w6300::ik_int_all);
    static uint8_t rx_buf[1518];
    for (int i = 0; i < 16 && w6300::get_socket_recv_buf(raw_socket) > 0; i++) {
        auto result = w6300::recv(raw_socket, std::span{rx_buf});
        if (!result) {
            break;
        }
        span_writer tx_writer(tx);
        process_frame({rx_buf, *result}, tx_writer);
    }
    w6300::rearm_gpio_irq();
}

} // namespace eth