well this built, we shall see if it works
/// Interface for networking hardware
pub const NetworkAdapter = struct {
    ptr: *anyopaque,
    vtable: *const VTable,
    pub const VTable = struct {
        write: *const fn (ctx: *anyopaque, data: []const u8) anyerror!usize,
        read: *const fn (ctx: *anyopaque, out: []u8) anyerror!usize,
    };
    pub fn write(self: NetworkAdapter, data: []const u8) anyerror!usize {
        return try self.vtable.write(self.ptr, data);
    }
    pub fn read(self: NetworkAdapter, out: []u8) anyerror!usize {
        return try self.vtable.read(self.ptr, out);
    }
};
/// Raw socket implementation for NetworkAdapter
pub const RawSocket = struct {
    socket: std.posix.socket_t,
    pub fn init(
        ifname: []const u8,
    ) !RawSocket {
        assert(ifname.len <= std.posix.IFNAMESIZE - 1); // ifname too long
        const socket: std.posix.socket_t = try std.posix.socket(
            std.posix.AF.PACKET,
            std.posix.SOCK.RAW,
            std.mem.nativeToBig(u32, ETH_P_ETHERCAT),
        );
        var timeout_rcv = std.posix.timeval{
            .sec = 0,
            .usec = 1,
        };
        try std.posix.setsockopt(
            socket,
            std.posix.SOL.SOCKET,
            std.posix.SO.RCVTIMEO,
            std.mem.asBytes(&timeout_rcv),
        );
        var timeout_snd = std.posix.timeval{
            .sec = 0,
            .usec = 1,
        };
        try std.posix.setsockopt(
            socket,
            std.posix.SOL.SOCKET,
            std.posix.SO.SNDTIMEO,
            std.mem.asBytes(&timeout_snd),
        );
        const dontroute_enable: c_int = 1;
        try std.posix.setsockopt(
            socket,
            std.posix.SOL.SOCKET,
            std.posix.SO.DONTROUTE,
            std.mem.asBytes(&dontroute_enable),
        );
        var ifr: std.posix.ifreq = std.mem.zeroInit(std.posix.ifreq, .{});
        @memcpy(ifr.ifrn.name[0..ifname.len], ifname);
        ifr.ifrn.name[ifname.len] = 0;
        try std.posix.ioctl_SIOCGIFINDEX(socket, &ifr);
        const ifindex: i32 = ifr.ifru.ivalue;
        const IFF_PROMISC = 256;
        const IFF_BROADCAST = 2;
        const SIOCGIFFLAGS = 0x8913;
        const SIOCSIFFLAGS = 0x8914;
        var rval = std.posix.errno(std.os.linux.ioctl(socket, SIOCGIFFLAGS, @intFromPtr(&ifr)));
        switch (rval) {
            .SUCCESS => {},
            else => {
                return error.nicError;
            },
        }
        ifr.ifru.flags = ifr.ifru.flags | IFF_BROADCAST | IFF_PROMISC;
        rval = std.posix.errno(std.os.linux.ioctl(socket, SIOCSIFFLAGS, @intFromPtr(&ifr)));
        switch (rval) {
            .SUCCESS => {},
            else => {
                return error.nicError;
            },
        }
        const sockaddr_ll = std.posix.sockaddr.ll{
            .family = std.posix.AF.PACKET,
            .ifindex = ifindex,
            .protocol = std.mem.nativeToBig(u16, @as(u16, ETH_P_ETHERCAT)),
            .halen = 0, //not used
            .addr = .{ 0, 0, 0, 0, 0, 0, 0, 0 }, //not used
            .pkttype = 0, //not used
            .hatype = 0, //not used
        };
        try std.posix.bind(socket, @ptrCast(&sockaddr_ll), @sizeOf(@TypeOf(sockaddr_ll)));
        return RawSocket{
            .socket = socket,
        };
    }
    pub fn deinit(self: *RawSocket) void {
        _ = self;
        // TODO: de init socket
    }
    pub fn write(ctx: *anyopaque, bytes: []const u8) std.posix.WriteError!usize {
        const self: *RawSocket = @ptrCast(@alignCast(ctx));
        return try std.posix.write(self.socket, bytes);
    }
    pub fn read(ctx: *anyopaque, out: []u8) std.posix.ReadError!usize {
        const self: *RawSocket = @ptrCast(@alignCast(ctx));
        return try std.posix.read(self.socket, out);
    }
    pub fn networkAdapter(self: *RawSocket) NetworkAdapter {
        return NetworkAdapter{
            .ptr = self,
            .vtable = &.{ .write = write, .read = read },
        };
    }
};
edit: It works!