fidl_fuchsia_net_ndp__common/

fidl_fuchsia_net_ndp__common.rs

// WARNING: This file is machine generated by fidlgen.

#![warn(clippy::all)]
#![allow(unused_parens, unused_mut, unused_imports, nonstandard_style)]

use bitflags::bitflags;
use fidl::encoding::{MessageBufFor, ProxyChannelBox, ResourceDialect};
use futures::future::{self, MaybeDone, TryFutureExt};
use zx_status;

/// The identifier of an NDP option type, aka the "type" field in the NDP option
/// as described in [RFC 4861 section
/// 4.6](https://datatracker.ietf.org/doc/html/rfc4861#section-4.6).
pub type OptionType = u8;

/// The maximum number of distinct option types that can be specified for
/// watcher interest.
pub const MAX_NUM_OPTION_TYPES: u16 = 256;

/// The maximum number of options that can be yielded in a single watcher batch.
pub const MAX_OPTION_BATCH_SIZE: u8 = 16;

/// The maximum possible length in bytes of an NDP option body (excluding the
/// type and length bytes).
pub const MAX_OPTION_BODY_LENGTH: u16 = 2038;

#[derive(Clone, Debug, PartialEq)]
pub struct OptionWatcherWatchOptionsResponse {
    /// A batch of yielded options.
    pub options: Vec<OptionWatchEntry>,
    /// A count of the number of options dropped since the last time
    /// `WatchOptions` was called (or since the watcher was created if this
    /// is the first time it was called).
    pub dropped: u32,
}

impl fidl::Persistable for OptionWatcherWatchOptionsResponse {}

/// An entry representing a single option received in an NDP message.
///
/// The `option_type` and `body` are not guaranteed to be validated in any way
/// other than the `body` conforming to length requirements as specified in [RFC
/// 4861 section
/// 4.6](https://datatracker.ietf.org/doc/html/rfc4861#section-4.6).
#[derive(Clone, Debug, Default, PartialEq)]
pub struct OptionWatchEntry {
    /// The interface on which the NDP message containing the option was
    /// received.
    ///
    /// Always present.
    pub interface_id: Option<u64>,
    /// The source address of the IPv6 packet containing the NDP message in
    /// which the option was received.
    ///
    /// Always present.
    pub source_address: Option<fidl_fuchsia_net__common::Ipv6Address>,
    /// The NDP option type.
    ///
    /// Always present.
    pub option_type: Option<u8>,
    /// The body of the NDP option.
    ///
    /// The raw bytes of the NDP option excluding the leading two bytes for the
    /// type and the length according to [RFC 4861 section
    /// 4.6](https://datatracker.ietf.org/doc/html/rfc4861#section-4.6). The
    /// body is padded such that if it were prepended with a type octet and a
    /// length octet to match the format described in RFC 4861 section 4.6, its
    /// length would be a multiple of 8 octets (as required by the RFC).
    ///
    /// Always present.
    pub body: Option<Vec<u8>>,
    #[doc(hidden)]
    pub __source_breaking: fidl::marker::SourceBreaking,
}

impl fidl::Persistable for OptionWatchEntry {}

/// Parameters for a router advertisement option watcher.
#[derive(Clone, Debug, Default, PartialEq)]
pub struct RouterAdvertisementOptionWatcherParams {
    /// The set of option types that should be yielded on the watcher.
    ///
    /// Indicates all option types should be yielded if absent.
    pub interest_types: Option<Vec<u8>>,
    /// If set, only options received via the specified interface will be
    /// yielded.
    ///
    /// Indicates options received via all interfaces should be yielded if
    /// absent.
    pub interest_interface_id: Option<u64>,
    #[doc(hidden)]
    pub __source_breaking: fidl::marker::SourceBreaking,
}

impl fidl::Persistable for RouterAdvertisementOptionWatcherParams {}

mod internal {
    use super::*;

    impl fidl::encoding::ValueTypeMarker for OptionWatcherWatchOptionsResponse {
        type Borrowed<'a> = &'a Self;
        fn borrow(value: &<Self as fidl::encoding::TypeMarker>::Owned) -> Self::Borrowed<'_> {
            value
        }
    }

    unsafe impl fidl::encoding::TypeMarker for OptionWatcherWatchOptionsResponse {
        type Owned = Self;

        #[inline(always)]
        fn inline_align(_context: fidl::encoding::Context) -> usize {
            8
        }

        #[inline(always)]
        fn inline_size(_context: fidl::encoding::Context) -> usize {
            24
        }
    }

    unsafe impl<D: fidl::encoding::ResourceDialect>
        fidl::encoding::Encode<OptionWatcherWatchOptionsResponse, D>
        for &OptionWatcherWatchOptionsResponse
    {
        #[inline]
        unsafe fn encode(
            self,
            encoder: &mut fidl::encoding::Encoder<'_, D>,
            offset: usize,
            _depth: fidl::encoding::Depth,
        ) -> fidl::Result<()> {
            encoder.debug_check_bounds::<OptionWatcherWatchOptionsResponse>(offset);
            // Delegate to tuple encoding.
            fidl::encoding::Encode::<OptionWatcherWatchOptionsResponse, D>::encode(
                (
                    <fidl::encoding::Vector<OptionWatchEntry, 16> as fidl::encoding::ValueTypeMarker>::borrow(&self.options),
                    <u32 as fidl::encoding::ValueTypeMarker>::borrow(&self.dropped),
                ),
                encoder, offset, _depth
            )
        }
    }
    unsafe impl<
            D: fidl::encoding::ResourceDialect,
            T0: fidl::encoding::Encode<fidl::encoding::Vector<OptionWatchEntry, 16>, D>,
            T1: fidl::encoding::Encode<u32, D>,
        > fidl::encoding::Encode<OptionWatcherWatchOptionsResponse, D> for (T0, T1)
    {
        #[inline]
        unsafe fn encode(
            self,
            encoder: &mut fidl::encoding::Encoder<'_, D>,
            offset: usize,
            depth: fidl::encoding::Depth,
        ) -> fidl::Result<()> {
            encoder.debug_check_bounds::<OptionWatcherWatchOptionsResponse>(offset);
            // Zero out padding regions. There's no need to apply masks
            // because the unmasked parts will be overwritten by fields.
            unsafe {
                let ptr = encoder.buf.as_mut_ptr().add(offset).offset(16);
                (ptr as *mut u64).write_unaligned(0);
            }
            // Write the fields.
            self.0.encode(encoder, offset + 0, depth)?;
            self.1.encode(encoder, offset + 16, depth)?;
            Ok(())
        }
    }

    impl<D: fidl::encoding::ResourceDialect> fidl::encoding::Decode<Self, D>
        for OptionWatcherWatchOptionsResponse
    {
        #[inline(always)]
        fn new_empty() -> Self {
            Self {
                options: fidl::new_empty!(fidl::encoding::Vector<OptionWatchEntry, 16>, D),
                dropped: fidl::new_empty!(u32, D),
            }
        }

        #[inline]
        unsafe fn decode(
            &mut self,
            decoder: &mut fidl::encoding::Decoder<'_, D>,
            offset: usize,
            _depth: fidl::encoding::Depth,
        ) -> fidl::Result<()> {
            decoder.debug_check_bounds::<Self>(offset);
            // Verify that padding bytes are zero.
            let ptr = unsafe { decoder.buf.as_ptr().add(offset).offset(16) };
            let padval = unsafe { (ptr as *const u64).read_unaligned() };
            let mask = 0xffffffff00000000u64;
            let maskedval = padval & mask;
            if maskedval != 0 {
                return Err(fidl::Error::NonZeroPadding {
                    padding_start: offset + 16 + ((mask as u64).trailing_zeros() / 8) as usize,
                });
            }
            fidl::decode!(fidl::encoding::Vector<OptionWatchEntry, 16>, D, &mut self.options, decoder, offset + 0, _depth)?;
            fidl::decode!(u32, D, &mut self.dropped, decoder, offset + 16, _depth)?;
            Ok(())
        }
    }

    impl OptionWatchEntry {
        #[inline(always)]
        fn max_ordinal_present(&self) -> u64 {
            if let Some(_) = self.body {
                return 4;
            }
            if let Some(_) = self.option_type {
                return 3;
            }
            if let Some(_) = self.source_address {
                return 2;
            }
            if let Some(_) = self.interface_id {
                return 1;
            }
            0
        }
    }

    impl fidl::encoding::ValueTypeMarker for OptionWatchEntry {
        type Borrowed<'a> = &'a Self;
        fn borrow(value: &<Self as fidl::encoding::TypeMarker>::Owned) -> Self::Borrowed<'_> {
            value
        }
    }

    unsafe impl fidl::encoding::TypeMarker for OptionWatchEntry {
        type Owned = Self;

        #[inline(always)]
        fn inline_align(_context: fidl::encoding::Context) -> usize {
            8
        }

        #[inline(always)]
        fn inline_size(_context: fidl::encoding::Context) -> usize {
            16
        }
    }

    unsafe impl<D: fidl::encoding::ResourceDialect> fidl::encoding::Encode<OptionWatchEntry, D>
        for &OptionWatchEntry
    {
        unsafe fn encode(
            self,
            encoder: &mut fidl::encoding::Encoder<'_, D>,
            offset: usize,
            mut depth: fidl::encoding::Depth,
        ) -> fidl::Result<()> {
            encoder.debug_check_bounds::<OptionWatchEntry>(offset);
            // Vector header
            let max_ordinal: u64 = self.max_ordinal_present();
            encoder.write_num(max_ordinal, offset);
            encoder.write_num(fidl::encoding::ALLOC_PRESENT_U64, offset + 8);
            // Calling encoder.out_of_line_offset(0) is not allowed.
            if max_ordinal == 0 {
                return Ok(());
            }
            depth.increment()?;
            let envelope_size = 8;
            let bytes_len = max_ordinal as usize * envelope_size;
            #[allow(unused_variables)]
            let offset = encoder.out_of_line_offset(bytes_len);
            let mut _prev_end_offset: usize = 0;
            if 1 > max_ordinal {
                return Ok(());
            }

            // Write at offset+(ordinal-1)*envelope_size, since ordinals are one-based and envelopes
            // are envelope_size bytes.
            let cur_offset: usize = (1 - 1) * envelope_size;

            // Zero reserved fields.
            encoder.padding(offset + _prev_end_offset, cur_offset - _prev_end_offset);

            // Safety:
            // - bytes_len is calculated to fit envelope_size*max(member.ordinal).
            // - Since cur_offset is envelope_size*(member.ordinal - 1) and the envelope takes
            //   envelope_size bytes, there is always sufficient room.
            fidl::encoding::encode_in_envelope_optional::<u64, D>(
                self.interface_id.as_ref().map(<u64 as fidl::encoding::ValueTypeMarker>::borrow),
                encoder,
                offset + cur_offset,
                depth,
            )?;

            _prev_end_offset = cur_offset + envelope_size;
            if 2 > max_ordinal {
                return Ok(());
            }

            // Write at offset+(ordinal-1)*envelope_size, since ordinals are one-based and envelopes
            // are envelope_size bytes.
            let cur_offset: usize = (2 - 1) * envelope_size;

            // Zero reserved fields.
            encoder.padding(offset + _prev_end_offset, cur_offset - _prev_end_offset);

            // Safety:
            // - bytes_len is calculated to fit envelope_size*max(member.ordinal).
            // - Since cur_offset is envelope_size*(member.ordinal - 1) and the envelope takes
            //   envelope_size bytes, there is always sufficient room.
            fidl::encoding::encode_in_envelope_optional::<fidl_fuchsia_net__common::Ipv6Address, D>(
            self.source_address.as_ref().map(<fidl_fuchsia_net__common::Ipv6Address as fidl::encoding::ValueTypeMarker>::borrow),
            encoder, offset + cur_offset, depth
        )?;

            _prev_end_offset = cur_offset + envelope_size;
            if 3 > max_ordinal {
                return Ok(());
            }

            // Write at offset+(ordinal-1)*envelope_size, since ordinals are one-based and envelopes
            // are envelope_size bytes.
            let cur_offset: usize = (3 - 1) * envelope_size;

            // Zero reserved fields.
            encoder.padding(offset + _prev_end_offset, cur_offset - _prev_end_offset);

            // Safety:
            // - bytes_len is calculated to fit envelope_size*max(member.ordinal).
            // - Since cur_offset is envelope_size*(member.ordinal - 1) and the envelope takes
            //   envelope_size bytes, there is always sufficient room.
            fidl::encoding::encode_in_envelope_optional::<u8, D>(
                self.option_type.as_ref().map(<u8 as fidl::encoding::ValueTypeMarker>::borrow),
                encoder,
                offset + cur_offset,
                depth,
            )?;

            _prev_end_offset = cur_offset + envelope_size;
            if 4 > max_ordinal {
                return Ok(());
            }

            // Write at offset+(ordinal-1)*envelope_size, since ordinals are one-based and envelopes
            // are envelope_size bytes.
            let cur_offset: usize = (4 - 1) * envelope_size;

            // Zero reserved fields.
            encoder.padding(offset + _prev_end_offset, cur_offset - _prev_end_offset);

            // Safety:
            // - bytes_len is calculated to fit envelope_size*max(member.ordinal).
            // - Since cur_offset is envelope_size*(member.ordinal - 1) and the envelope takes
            //   envelope_size bytes, there is always sufficient room.
            fidl::encoding::encode_in_envelope_optional::<fidl::encoding::Vector<u8, 2038>, D>(
                self.body.as_ref().map(
                    <fidl::encoding::Vector<u8, 2038> as fidl::encoding::ValueTypeMarker>::borrow,
                ),
                encoder,
                offset + cur_offset,
                depth,
            )?;

            _prev_end_offset = cur_offset + envelope_size;

            Ok(())
        }
    }

    impl<D: fidl::encoding::ResourceDialect> fidl::encoding::Decode<Self, D> for OptionWatchEntry {
        #[inline(always)]
        fn new_empty() -> Self {
            Self::default()
        }

        unsafe fn decode(
            &mut self,
            decoder: &mut fidl::encoding::Decoder<'_, D>,
            offset: usize,
            mut depth: fidl::encoding::Depth,
        ) -> fidl::Result<()> {
            decoder.debug_check_bounds::<Self>(offset);
            let len = match fidl::encoding::decode_vector_header(decoder, offset)? {
                None => return Err(fidl::Error::NotNullable),
                Some(len) => len,
            };
            // Calling decoder.out_of_line_offset(0) is not allowed.
            if len == 0 {
                return Ok(());
            };
            depth.increment()?;
            let envelope_size = 8;
            let bytes_len = len * envelope_size;
            let offset = decoder.out_of_line_offset(bytes_len)?;
            // Decode the envelope for each type.
            let mut _next_ordinal_to_read = 0;
            let mut next_offset = offset;
            let end_offset = offset + bytes_len;
            _next_ordinal_to_read += 1;
            if next_offset >= end_offset {
                return Ok(());
            }

            // Decode unknown envelopes for gaps in ordinals.
            while _next_ordinal_to_read < 1 {
                fidl::encoding::decode_unknown_envelope(decoder, next_offset, depth)?;
                _next_ordinal_to_read += 1;
                next_offset += envelope_size;
            }

            let next_out_of_line = decoder.next_out_of_line();
            let handles_before = decoder.remaining_handles();
            if let Some((inlined, num_bytes, num_handles)) =
                fidl::encoding::decode_envelope_header(decoder, next_offset)?
            {
                let member_inline_size =
                    <u64 as fidl::encoding::TypeMarker>::inline_size(decoder.context);
                if inlined != (member_inline_size <= 4) {
                    return Err(fidl::Error::InvalidInlineBitInEnvelope);
                }
                let inner_offset;
                let mut inner_depth = depth.clone();
                if inlined {
                    decoder.check_inline_envelope_padding(next_offset, member_inline_size)?;
                    inner_offset = next_offset;
                } else {
                    inner_offset = decoder.out_of_line_offset(member_inline_size)?;
                    inner_depth.increment()?;
                }
                let val_ref = self.interface_id.get_or_insert_with(|| fidl::new_empty!(u64, D));
                fidl::decode!(u64, D, val_ref, decoder, inner_offset, inner_depth)?;
                if !inlined && decoder.next_out_of_line() != next_out_of_line + (num_bytes as usize)
                {
                    return Err(fidl::Error::InvalidNumBytesInEnvelope);
                }
                if handles_before != decoder.remaining_handles() + (num_handles as usize) {
                    return Err(fidl::Error::InvalidNumHandlesInEnvelope);
                }
            }

            next_offset += envelope_size;
            _next_ordinal_to_read += 1;
            if next_offset >= end_offset {
                return Ok(());
            }

            // Decode unknown envelopes for gaps in ordinals.
            while _next_ordinal_to_read < 2 {
                fidl::encoding::decode_unknown_envelope(decoder, next_offset, depth)?;
                _next_ordinal_to_read += 1;
                next_offset += envelope_size;
            }

            let next_out_of_line = decoder.next_out_of_line();
            let handles_before = decoder.remaining_handles();
            if let Some((inlined, num_bytes, num_handles)) =
                fidl::encoding::decode_envelope_header(decoder, next_offset)?
            {
                let member_inline_size = <fidl_fuchsia_net__common::Ipv6Address as fidl::encoding::TypeMarker>::inline_size(decoder.context);
                if inlined != (member_inline_size <= 4) {
                    return Err(fidl::Error::InvalidInlineBitInEnvelope);
                }
                let inner_offset;
                let mut inner_depth = depth.clone();
                if inlined {
                    decoder.check_inline_envelope_padding(next_offset, member_inline_size)?;
                    inner_offset = next_offset;
                } else {
                    inner_offset = decoder.out_of_line_offset(member_inline_size)?;
                    inner_depth.increment()?;
                }
                let val_ref = self.source_address.get_or_insert_with(|| {
                    fidl::new_empty!(fidl_fuchsia_net__common::Ipv6Address, D)
                });
                fidl::decode!(
                    fidl_fuchsia_net__common::Ipv6Address,
                    D,
                    val_ref,
                    decoder,
                    inner_offset,
                    inner_depth
                )?;
                if !inlined && decoder.next_out_of_line() != next_out_of_line + (num_bytes as usize)
                {
                    return Err(fidl::Error::InvalidNumBytesInEnvelope);
                }
                if handles_before != decoder.remaining_handles() + (num_handles as usize) {
                    return Err(fidl::Error::InvalidNumHandlesInEnvelope);
                }
            }

            next_offset += envelope_size;
            _next_ordinal_to_read += 1;
            if next_offset >= end_offset {
                return Ok(());
            }

            // Decode unknown envelopes for gaps in ordinals.
            while _next_ordinal_to_read < 3 {
                fidl::encoding::decode_unknown_envelope(decoder, next_offset, depth)?;
                _next_ordinal_to_read += 1;
                next_offset += envelope_size;
            }

            let next_out_of_line = decoder.next_out_of_line();
            let handles_before = decoder.remaining_handles();
            if let Some((inlined, num_bytes, num_handles)) =
                fidl::encoding::decode_envelope_header(decoder, next_offset)?
            {
                let member_inline_size =
                    <u8 as fidl::encoding::TypeMarker>::inline_size(decoder.context);
                if inlined != (member_inline_size <= 4) {
                    return Err(fidl::Error::InvalidInlineBitInEnvelope);
                }
                let inner_offset;
                let mut inner_depth = depth.clone();
                if inlined {
                    decoder.check_inline_envelope_padding(next_offset, member_inline_size)?;
                    inner_offset = next_offset;
                } else {
                    inner_offset = decoder.out_of_line_offset(member_inline_size)?;
                    inner_depth.increment()?;
                }
                let val_ref = self.option_type.get_or_insert_with(|| fidl::new_empty!(u8, D));
                fidl::decode!(u8, D, val_ref, decoder, inner_offset, inner_depth)?;
                if !inlined && decoder.next_out_of_line() != next_out_of_line + (num_bytes as usize)
                {
                    return Err(fidl::Error::InvalidNumBytesInEnvelope);
                }
                if handles_before != decoder.remaining_handles() + (num_handles as usize) {
                    return Err(fidl::Error::InvalidNumHandlesInEnvelope);
                }
            }

            next_offset += envelope_size;
            _next_ordinal_to_read += 1;
            if next_offset >= end_offset {
                return Ok(());
            }

            // Decode unknown envelopes for gaps in ordinals.
            while _next_ordinal_to_read < 4 {
                fidl::encoding::decode_unknown_envelope(decoder, next_offset, depth)?;
                _next_ordinal_to_read += 1;
                next_offset += envelope_size;
            }

            let next_out_of_line = decoder.next_out_of_line();
            let handles_before = decoder.remaining_handles();
            if let Some((inlined, num_bytes, num_handles)) =
                fidl::encoding::decode_envelope_header(decoder, next_offset)?
            {
                let member_inline_size =
                    <fidl::encoding::Vector<u8, 2038> as fidl::encoding::TypeMarker>::inline_size(
                        decoder.context,
                    );
                if inlined != (member_inline_size <= 4) {
                    return Err(fidl::Error::InvalidInlineBitInEnvelope);
                }
                let inner_offset;
                let mut inner_depth = depth.clone();
                if inlined {
                    decoder.check_inline_envelope_padding(next_offset, member_inline_size)?;
                    inner_offset = next_offset;
                } else {
                    inner_offset = decoder.out_of_line_offset(member_inline_size)?;
                    inner_depth.increment()?;
                }
                let val_ref = self
                    .body
                    .get_or_insert_with(|| fidl::new_empty!(fidl::encoding::Vector<u8, 2038>, D));
                fidl::decode!(fidl::encoding::Vector<u8, 2038>, D, val_ref, decoder, inner_offset, inner_depth)?;
                if !inlined && decoder.next_out_of_line() != next_out_of_line + (num_bytes as usize)
                {
                    return Err(fidl::Error::InvalidNumBytesInEnvelope);
                }
                if handles_before != decoder.remaining_handles() + (num_handles as usize) {
                    return Err(fidl::Error::InvalidNumHandlesInEnvelope);
                }
            }

            next_offset += envelope_size;

            // Decode the remaining unknown envelopes.
            while next_offset < end_offset {
                _next_ordinal_to_read += 1;
                fidl::encoding::decode_unknown_envelope(decoder, next_offset, depth)?;
                next_offset += envelope_size;
            }

            Ok(())
        }
    }

    impl RouterAdvertisementOptionWatcherParams {
        #[inline(always)]
        fn max_ordinal_present(&self) -> u64 {
            if let Some(_) = self.interest_interface_id {
                return 2;
            }
            if let Some(_) = self.interest_types {
                return 1;
            }
            0
        }
    }

    impl fidl::encoding::ValueTypeMarker for RouterAdvertisementOptionWatcherParams {
        type Borrowed<'a> = &'a Self;
        fn borrow(value: &<Self as fidl::encoding::TypeMarker>::Owned) -> Self::Borrowed<'_> {
            value
        }
    }

    unsafe impl fidl::encoding::TypeMarker for RouterAdvertisementOptionWatcherParams {
        type Owned = Self;

        #[inline(always)]
        fn inline_align(_context: fidl::encoding::Context) -> usize {
            8
        }

        #[inline(always)]
        fn inline_size(_context: fidl::encoding::Context) -> usize {
            16
        }
    }

    unsafe impl<D: fidl::encoding::ResourceDialect>
        fidl::encoding::Encode<RouterAdvertisementOptionWatcherParams, D>
        for &RouterAdvertisementOptionWatcherParams
    {
        unsafe fn encode(
            self,
            encoder: &mut fidl::encoding::Encoder<'_, D>,
            offset: usize,
            mut depth: fidl::encoding::Depth,
        ) -> fidl::Result<()> {
            encoder.debug_check_bounds::<RouterAdvertisementOptionWatcherParams>(offset);
            // Vector header
            let max_ordinal: u64 = self.max_ordinal_present();
            encoder.write_num(max_ordinal, offset);
            encoder.write_num(fidl::encoding::ALLOC_PRESENT_U64, offset + 8);
            // Calling encoder.out_of_line_offset(0) is not allowed.
            if max_ordinal == 0 {
                return Ok(());
            }
            depth.increment()?;
            let envelope_size = 8;
            let bytes_len = max_ordinal as usize * envelope_size;
            #[allow(unused_variables)]
            let offset = encoder.out_of_line_offset(bytes_len);
            let mut _prev_end_offset: usize = 0;
            if 1 > max_ordinal {
                return Ok(());
            }

            // Write at offset+(ordinal-1)*envelope_size, since ordinals are one-based and envelopes
            // are envelope_size bytes.
            let cur_offset: usize = (1 - 1) * envelope_size;

            // Zero reserved fields.
            encoder.padding(offset + _prev_end_offset, cur_offset - _prev_end_offset);

            // Safety:
            // - bytes_len is calculated to fit envelope_size*max(member.ordinal).
            // - Since cur_offset is envelope_size*(member.ordinal - 1) and the envelope takes
            //   envelope_size bytes, there is always sufficient room.
            fidl::encoding::encode_in_envelope_optional::<fidl::encoding::Vector<u8, 256>, D>(
                self.interest_types.as_ref().map(
                    <fidl::encoding::Vector<u8, 256> as fidl::encoding::ValueTypeMarker>::borrow,
                ),
                encoder,
                offset + cur_offset,
                depth,
            )?;

            _prev_end_offset = cur_offset + envelope_size;
            if 2 > max_ordinal {
                return Ok(());
            }

            // Write at offset+(ordinal-1)*envelope_size, since ordinals are one-based and envelopes
            // are envelope_size bytes.
            let cur_offset: usize = (2 - 1) * envelope_size;

            // Zero reserved fields.
            encoder.padding(offset + _prev_end_offset, cur_offset - _prev_end_offset);

            // Safety:
            // - bytes_len is calculated to fit envelope_size*max(member.ordinal).
            // - Since cur_offset is envelope_size*(member.ordinal - 1) and the envelope takes
            //   envelope_size bytes, there is always sufficient room.
            fidl::encoding::encode_in_envelope_optional::<u64, D>(
                self.interest_interface_id
                    .as_ref()
                    .map(<u64 as fidl::encoding::ValueTypeMarker>::borrow),
                encoder,
                offset + cur_offset,
                depth,
            )?;

            _prev_end_offset = cur_offset + envelope_size;

            Ok(())
        }
    }

    impl<D: fidl::encoding::ResourceDialect> fidl::encoding::Decode<Self, D>
        for RouterAdvertisementOptionWatcherParams
    {
        #[inline(always)]
        fn new_empty() -> Self {
            Self::default()
        }

        unsafe fn decode(
            &mut self,
            decoder: &mut fidl::encoding::Decoder<'_, D>,
            offset: usize,
            mut depth: fidl::encoding::Depth,
        ) -> fidl::Result<()> {
            decoder.debug_check_bounds::<Self>(offset);
            let len = match fidl::encoding::decode_vector_header(decoder, offset)? {
                None => return Err(fidl::Error::NotNullable),
                Some(len) => len,
            };
            // Calling decoder.out_of_line_offset(0) is not allowed.
            if len == 0 {
                return Ok(());
            };
            depth.increment()?;
            let envelope_size = 8;
            let bytes_len = len * envelope_size;
            let offset = decoder.out_of_line_offset(bytes_len)?;
            // Decode the envelope for each type.
            let mut _next_ordinal_to_read = 0;
            let mut next_offset = offset;
            let end_offset = offset + bytes_len;
            _next_ordinal_to_read += 1;
            if next_offset >= end_offset {
                return Ok(());
            }

            // Decode unknown envelopes for gaps in ordinals.
            while _next_ordinal_to_read < 1 {
                fidl::encoding::decode_unknown_envelope(decoder, next_offset, depth)?;
                _next_ordinal_to_read += 1;
                next_offset += envelope_size;
            }

            let next_out_of_line = decoder.next_out_of_line();
            let handles_before = decoder.remaining_handles();
            if let Some((inlined, num_bytes, num_handles)) =
                fidl::encoding::decode_envelope_header(decoder, next_offset)?
            {
                let member_inline_size =
                    <fidl::encoding::Vector<u8, 256> as fidl::encoding::TypeMarker>::inline_size(
                        decoder.context,
                    );
                if inlined != (member_inline_size <= 4) {
                    return Err(fidl::Error::InvalidInlineBitInEnvelope);
                }
                let inner_offset;
                let mut inner_depth = depth.clone();
                if inlined {
                    decoder.check_inline_envelope_padding(next_offset, member_inline_size)?;
                    inner_offset = next_offset;
                } else {
                    inner_offset = decoder.out_of_line_offset(member_inline_size)?;
                    inner_depth.increment()?;
                }
                let val_ref = self
                    .interest_types
                    .get_or_insert_with(|| fidl::new_empty!(fidl::encoding::Vector<u8, 256>, D));
                fidl::decode!(fidl::encoding::Vector<u8, 256>, D, val_ref, decoder, inner_offset, inner_depth)?;
                if !inlined && decoder.next_out_of_line() != next_out_of_line + (num_bytes as usize)
                {
                    return Err(fidl::Error::InvalidNumBytesInEnvelope);
                }
                if handles_before != decoder.remaining_handles() + (num_handles as usize) {
                    return Err(fidl::Error::InvalidNumHandlesInEnvelope);
                }
            }

            next_offset += envelope_size;
            _next_ordinal_to_read += 1;
            if next_offset >= end_offset {
                return Ok(());
            }

            // Decode unknown envelopes for gaps in ordinals.
            while _next_ordinal_to_read < 2 {
                fidl::encoding::decode_unknown_envelope(decoder, next_offset, depth)?;
                _next_ordinal_to_read += 1;
                next_offset += envelope_size;
            }

            let next_out_of_line = decoder.next_out_of_line();
            let handles_before = decoder.remaining_handles();
            if let Some((inlined, num_bytes, num_handles)) =
                fidl::encoding::decode_envelope_header(decoder, next_offset)?
            {
                let member_inline_size =
                    <u64 as fidl::encoding::TypeMarker>::inline_size(decoder.context);
                if inlined != (member_inline_size <= 4) {
                    return Err(fidl::Error::InvalidInlineBitInEnvelope);
                }
                let inner_offset;
                let mut inner_depth = depth.clone();
                if inlined {
                    decoder.check_inline_envelope_padding(next_offset, member_inline_size)?;
                    inner_offset = next_offset;
                } else {
                    inner_offset = decoder.out_of_line_offset(member_inline_size)?;
                    inner_depth.increment()?;
                }
                let val_ref =
                    self.interest_interface_id.get_or_insert_with(|| fidl::new_empty!(u64, D));
                fidl::decode!(u64, D, val_ref, decoder, inner_offset, inner_depth)?;
                if !inlined && decoder.next_out_of_line() != next_out_of_line + (num_bytes as usize)
                {
                    return Err(fidl::Error::InvalidNumBytesInEnvelope);
                }
                if handles_before != decoder.remaining_handles() + (num_handles as usize) {
                    return Err(fidl::Error::InvalidNumHandlesInEnvelope);
                }
            }

            next_offset += envelope_size;

            // Decode the remaining unknown envelopes.
            while next_offset < end_offset {
                _next_ordinal_to_read += 1;
                fidl::encoding::decode_unknown_envelope(decoder, next_offset, depth)?;
                next_offset += envelope_size;
            }

            Ok(())
        }
    }
}