crushtool 0.3.10

//! Decompile a ceph crushmap for fun and profit
//!
//!
//! CRUSH is a pseudo-random data distribution algorithm that
//! efficiently distributes input values (typically, data objects)
//! across a heterogeneous, structured storage cluster.
//!
//! The algorithm was originally described in detail in this paper
//! (although the algorithm has evolved somewhat since then):
//! http://www.ssrc.ucsc.edu/Papers/weil-sc06.pdf
//!
use std::error::Error;
use std::fmt;
use std::io::{self, ErrorKind};
use std::string::FromUtf8Error;

use byteorder::{LittleEndian, WriteBytesExt};
use num::FromPrimitive;
use nom::{IResult, le_u8, le_u16, le_i32, le_u32};


use ::{EncodingError, BucketAlg, RuleType, CrushHash, OpCode, CrushBucketUniform, CrushBucketList,
       CrushBucketTree, CrushBucketStraw2, CrushBucketStraw, BucketTypes, Bucket, CrushRuleStep,
       CrushRuleMask, Rule, CrushMap};


static CRUSH_MAGIC: u32 = 0x00010000;  /* for detecting algorithm revisions */

impl EncodingError {
    pub fn new(err: String) -> EncodingError {
        EncodingError::IoError(io::Error::new(ErrorKind::Other, err))
    }
    pub fn to_string(&self) -> String {
        match *self {
            EncodingError::IoError(ref err) => err.description().to_string(),
            EncodingError::InvalidValue => "Invalid Value".to_string(),
            EncodingError::InvalidType => "Invalid Type".to_string(),
            EncodingError::FromUtf8Error(ref err) => err.utf8_error().to_string(),
        }
    }
}

impl From<FromUtf8Error> for EncodingError {
    fn from(err: FromUtf8Error) -> EncodingError {
        EncodingError::FromUtf8Error(err)
    }
}

impl From<io::Error> for EncodingError {
    fn from(err: io::Error) -> EncodingError {
        EncodingError::IoError(err)
    }
}

// trait Parse {
//     fn parse<'a>(input: &'a [u8]) -> IResult<&[u8], Self>;
//     fn compile(&self) -> Result<Vec<u8>, EncodingError>;
// }

impl CrushBucketUniform {
    fn parse<'a>(input: &'a [u8]) -> IResult<&[u8], Self> {
        chain!(
            input,
            bucket: call!(Bucket::parse)~
            weight: le_u32,
            ||{
                CrushBucketUniform{
                    bucket: bucket,
                    item_weight: weight,
                }
            }
        )
    }

    fn compile(&self) -> Result<Vec<u8>, EncodingError> {
        let mut buffer: Vec<u8> = Vec::new();
        buffer.extend(try!(self.bucket.compile()));
        try!(buffer.write_u32::<LittleEndian>(self.item_weight));

        Ok(buffer)
    }
}

impl CrushBucketList {
    fn parse<'a>(input: &'a [u8]) -> IResult<&[u8], Self> {
        chain!(
            input,
            bucket: call!(Bucket::parse)~
            item_weights: count!(
                pair!(le_u32, le_u32),
                bucket.size as usize),
            ||{
                CrushBucketList{
                    bucket: bucket,
                    item_weights: item_weights,
                }
            }
        )
    }

    fn compile(&self) -> Result<Vec<u8>, EncodingError> {
        let mut buffer: Vec<u8> = Vec::new();
        buffer.extend(try!(self.bucket.compile()));

        for weights in self.item_weights.iter() {
            try!(buffer.write_u32::<LittleEndian>(weights.0));
            try!(buffer.write_u32::<LittleEndian>(weights.1));
        }

        Ok(buffer)
    }
}

impl CrushBucketTree {
    fn parse<'a>(input: &'a [u8]) -> IResult<&[u8], Self> {
        chain!(
            input,
            bucket: call!(Bucket::parse)~
            num_nodes: le_u8~
            node_weights: count!(le_u32, num_nodes as usize),
            ||{
                CrushBucketTree{
                    bucket: bucket,
                    num_nodes: num_nodes,
                    node_weights: node_weights
                }
            }
        )
    }
    fn compile(&self) -> Result<Vec<u8>, EncodingError> {
        let mut buffer: Vec<u8> = Vec::new();
        buffer.extend(try!(self.bucket.compile()));

        try!(buffer.write_u8(self.num_nodes));

        for weight in self.node_weights.iter() {
            try!(buffer.write_u32::<LittleEndian>(*weight));
        }

        Ok(buffer)
    }
}

impl CrushBucketStraw2 {
    fn parse<'a>(input: &'a [u8]) -> IResult<&[u8], Self> {
        chain!(
            input,
            bucket: call!(Bucket::parse)~
            item_weights: count!(le_u32, bucket.size as usize),
            ||{
                CrushBucketStraw2{
                    bucket: bucket,
                    item_weights: item_weights,
                }
            }
        )
    }
    fn compile(&self) -> Result<Vec<u8>, EncodingError> {
        let mut buffer: Vec<u8> = Vec::new();
        buffer.extend(try!(self.bucket.compile()));

        for weight in self.item_weights.iter() {
            try!(buffer.write_u32::<LittleEndian>(*weight));
        }

        Ok(buffer)
    }
}

impl fmt::Debug for CrushBucketStraw2 {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f,
            r#"Straw(CrushBucketStraw {{
                bucket: Bucket {{
                    id: {},
                    bucket_type: {:?},
                    alg: {:?},
                    hash: {:?},
                    weight: {},
                    size: {},
                    items: {:?},
                    perm_n: {},
                    perm: {}
                }},
                item_weights: {:?}
            }})"#,
            self.bucket.id,
            self.bucket.bucket_type,
            self.bucket.alg,
            self.bucket.hash,
            self.bucket.weight,
            self.bucket.size,
            self.bucket.items,
            self.bucket.perm_n,
            self.bucket.perm,
            self.item_weights,
        )
    }
}

impl CrushBucketStraw {
    fn parse<'a>(input: &'a [u8]) -> IResult<&[u8], Self> {
        chain!(
            input,
            bucket: call!(Bucket::parse)~
            item_weights: count!(pair!(le_u32, le_u32), bucket.size as usize),
            //straws: le_u32,
            ||{
                CrushBucketStraw{
                    bucket: bucket,
                    item_weights: item_weights,
                    //straws: straws,
                }
            }
        )
    }
    fn compile(&self) -> Result<Vec<u8>, EncodingError> {
        let mut buffer: Vec<u8> = Vec::new();
        buffer.extend(try!(self.bucket.compile()));

        for weights in self.item_weights.iter() {
            try!(buffer.write_u32::<LittleEndian>(weights.0));
            try!(buffer.write_u32::<LittleEndian>(weights.1));
        }

        Ok(buffer)
    }
}

impl fmt::Debug for CrushBucketStraw {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f,
            r#"Straw(CrushBucketStraw {{
                bucket: Bucket {{
                    id: {},
                    bucket_type: {:?},
                    alg: {:?},
                    hash: {:?},
                    weight: {},
                    size: {},
                    items: {:?},
                    perm_n: {},
                    perm: {}
                }},
                item_weights: {:?}
            }})"#,
            self.bucket.id,
            self.bucket.bucket_type,
            self.bucket.alg,
            self.bucket.hash,
            self.bucket.weight,
            self.bucket.size,
            self.bucket.items,
            self.bucket.perm_n,
            self.bucket.perm,
            self.item_weights,
        )
    }
}

named!(decode_32_or_64<&[u8], u32>,
    chain!(
        a: le_u32~
// if a ==0 take another u32
        b: cond!(a==0, le_u32),
        ||{
            b.unwrap_or(a)
        }
    )
);

// This silly function is needed because we don't know the name_map while
// parsing the crush buckets. Only after we're finished parsing the crushmap
// do we know the names
fn none(input: &[u8]) -> IResult<&[u8], Option<String>> {
    IResult::Done(input, None)
}

fn try_le_u8(input: &[u8]) -> IResult<&[u8], Option<u8>> {
    if input.len() < 1 {
        IResult::Done(input, None)
    } else {
        chain!(input,
            a: le_u8,
            ||{
                Some(a)
            }
        )
    }
}

fn try_le_u32(input: &[u8]) -> IResult<&[u8], Option<u32>> {
    if input.len() < 4 {
        IResult::Done(input, None)
    } else {
        chain!(input,
            a: le_u32,
            ||{
                Some(a)
            }
        )
    }
}

fn parse_string(i: &[u8]) -> IResult<&[u8], String> {
    trace!("parse_string input: {:?}", i);
    chain!(i,
        length: decode_32_or_64 ~
        s: dbg!(take_str!(length)),
        ||{
            s.to_string()
        }
    )
}

fn parse_string_map(input: &[u8]) -> IResult<&[u8], Vec<(i32, String)>> {
    trace!("parse_string_map input: {:?}", input);
    chain!(input,
        count: le_u32~
        string_map: dbg!(
            count!(
                pair!(le_i32,
                    dbg!(call!(parse_string))), count as usize)),
        ||{
            string_map
        }
    )
}

pub fn encode_string_map(input: Vec<(i32, String)>) -> Result<Vec<u8>, EncodingError> {
    let mut buffer = Vec::new();
    // Count
    try!(buffer.write_u32::<LittleEndian>(input.len() as u32));

    for pair in input.into_iter() {
        try!(buffer.write_i32::<LittleEndian>(pair.0));

        // String length
        try!(buffer.write_u32::<LittleEndian>(pair.1.len() as u32));
        // String data
        buffer.extend(pair.1.into_bytes());
    }

    Ok(buffer)
}

fn parse_bucket<'a>(input: &'a [u8]) -> IResult<&[u8], BucketTypes> {
    trace!("parse_bucket input: {:?}", input);
    let alg_type_bits = le_u32(input);
    match alg_type_bits {
        IResult::Done(unparsed_data, alg_bits) => {
            let some_alg = BucketAlg::from_u32(alg_bits);
            let alg = match some_alg {
                Some(t) => t,
                None => {
                    trace!("Unknown bucket: {:?}", alg_bits);
                    return IResult::Done(unparsed_data, BucketTypes::Unknown);
                }
            };
            match alg {
                BucketAlg::Uniform => {
                    trace!("Trying to decode uniform bucket");
                    chain!(
                        input,
                        uniform_bucket: dbg!(call!(CrushBucketUniform::parse)),
                        ||{
                            BucketTypes::Uniform(uniform_bucket)
                        }
                    )
                }
                BucketAlg::List => {
                    trace!("Trying to decode list bucket");
                    chain!(
                        input,
                        list_bucket: dbg!(call!(CrushBucketList::parse)),
                        ||{
                            BucketTypes::List(list_bucket)
                        }
                    )
                }
                BucketAlg::Tree => {
                    trace!("Trying to decode tree bucket");
                    chain!(
                        input,
                        tree_bucket: dbg!(call!(CrushBucketTree::parse)),
                        ||{
                            BucketTypes::Tree(tree_bucket)
                        }
                    )
                }
                BucketAlg::Straw => {
                    trace!("Trying to decode straw bucket");
                    chain!(
                        input,
                        straw_bucket: dbg!(call!(CrushBucketStraw::parse)),
                        ||{
                            BucketTypes::Straw(straw_bucket)
                        }
                    )
                }
                BucketAlg::Straw2 => {
                    trace!("Trying to decode straw2 bucket");
                    chain!(
                        input,
                        straw_bucket: dbg!(call!(CrushBucketStraw2::parse)),
                        ||{
                            BucketTypes::Straw2(straw_bucket)
                        }
                    )
                }
            }
        }
        IResult::Incomplete(needed) => {
            return IResult::Incomplete(needed);
        }
        IResult::Error(e) => {
            return IResult::Error(e);
        }
    }
}

impl Bucket {
    fn parse<'a>(input: &'a [u8]) -> IResult<&[u8], Self> {
        trace!("bucket input: {:?}", input);
        chain!(
            input,
            le_u32~
            //switch on algorithm
            id: le_i32~
            bucket_type_bits: le_u16 ~
            bucket_type: expr_opt!(OpCode::from_u16(bucket_type_bits)) ~
            alg_bits: le_u8~
            alg: expr_opt!(BucketAlg::from_u8(alg_bits))~
            hash_bits: le_u8~
            hash: expr_opt!(CrushHash::from_u8(hash_bits))~
            weight: le_u32~
            size: le_u32~
            items: dbg!(
                count!(
                    pair!(le_i32, call!(none)), size as usize
                )
            ),
            ||{
                Bucket{
                    id: id,
                    bucket_type: bucket_type,
                    alg: alg,
                    hash: hash,
                    weight: weight,
                    size: size,
                    perm_n: 0,
                    perm: size,
                    items: items,
                }
            }
        )
    }
    fn compile(&self) -> Result<Vec<u8>, EncodingError> {
        let mut buffer: Vec<u8> = Vec::new();
        try!(buffer.write_u32::<LittleEndian>(self.alg.clone() as u32));
        try!(buffer.write_i32::<LittleEndian>(self.id));
        try!(buffer.write_u16::<LittleEndian>(self.bucket_type.clone() as u16));
        try!(buffer.write_u8(self.alg.clone() as u8));
        try!(buffer.write_u8(self.hash.clone() as u8));
        try!(buffer.write_u32::<LittleEndian>(self.weight));
        try!(buffer.write_u32::<LittleEndian>(self.size));

        for item in self.items.iter() {
            try!(buffer.write_i32::<LittleEndian>(item.0));
        }

        Ok(buffer)
    }

    fn update_name_mapping(&mut self, name_map: &Vec<(i32, String)>) {
        trace!("Updating name mapping with {:?}", name_map);
        let mut new_items: Vec<(i32, Option<String>)> = Vec::with_capacity(self.items.len());

        // I want to preserve the vec ordering
        for item_tuple in self.items.iter_mut() {
            let mut resolved_item: (i32, Option<String>) = (item_tuple.0, None);

            for name in name_map {
                if name.0 == item_tuple.0 {
                    resolved_item.1 = Some(name.1.clone());
                }
            }
            new_items.push(resolved_item);
        }
        self.items = new_items;
    }
}

impl CrushRuleStep {
    fn parse<'a>(input: &'a [u8]) -> IResult<&[u8], Self> {
        trace!("rule step input: {:?}", input);
        chain!(
            input,
            op_bits: le_u32~
            op_code: expr_opt!(OpCode::from_u32(op_bits)) ~
            arg1: le_i32~
            arg2: le_i32,
            ||{
                CrushRuleStep{
                    op: op_code,
                    //These get resolved later once we know the type_map
                    arg1: (arg1, None),
                    arg2: (arg2, None),
                }
            }
        )
    }
    // Change the arg's.1 from None to a proper name
    fn update_arg_mapping(&mut self, type_map: &Vec<(i32, String)>) {
        trace!("Updating arg mapping with {:?}", type_map);
        for tuple in type_map {
            if tuple.0 == self.arg1.0 {
                self.arg1.1 = Some(tuple.1.clone());
            }
            if tuple.0 == self.arg2.0 {
                self.arg2.1 = Some(tuple.1.clone());
            }
        }
    }
    fn compile(&self) -> Result<Vec<u8>, EncodingError> {
        let mut buffer: Vec<u8> = Vec::new();
        try!(buffer.write_u32::<LittleEndian>(self.op.clone() as u32));
        try!(buffer.write_i32::<LittleEndian>(self.arg1.0));
        try!(buffer.write_i32::<LittleEndian>(self.arg2.0));

        Ok(buffer)
    }
}

impl fmt::Debug for CrushRuleStep {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f,
            r#"CrushRuleStep {{
                op: {:?},
                arg1: {:?},
                arg2: {:?},
            }}"#,
            self.op,
            self.arg1,
            self.arg2,
        )
    }
}

impl CrushRuleMask {
    fn parse<'a>(input: &'a [u8]) -> IResult<&[u8], Self> {
        trace!("rule mask input: {:?}", input);
        chain!(
            input,
            ruleset: le_u8~
            rule_type_bits: le_u8 ~
            rule_type: expr_opt!(RuleType::from_u8(rule_type_bits)) ~
            min_size: le_u8~
            max_size: le_u8,
            ||{
                CrushRuleMask{
                    ruleset: ruleset,
                    rule_type: rule_type,
                    min_size: min_size,
                    max_size: max_size,
                }
            }
        )
    }
    fn compile(&self) -> Result<Vec<u8>, EncodingError> {
        let mut buffer: Vec<u8> = Vec::new();
        try!(buffer.write_u8(self.ruleset));
        try!(buffer.write_u8(self.rule_type.clone() as u8));
        try!(buffer.write_u8(self.min_size));
        try!(buffer.write_u8(self.max_size));

        Ok(buffer)
    }
}

impl fmt::Debug for CrushRuleMask {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f,
            r#"CrushRuleMask {{
                ruleset: {},
                rule_type: {:?},
                min_size: {},
                max_size: {},
            }}"#,
            self.ruleset,
            self.rule_type,
            self.min_size,
            self.max_size,
        )
    }
}

impl Rule {
    fn parse<'a>(input: &'a [u8]) -> IResult<&[u8], Option<Self>> {
        trace!("rule input: {:?}", input);
        let yes_bits = le_u32(input);
        match yes_bits {
            IResult::Done(unparsed_data, yes) => {
                if yes == 0 {
                    return IResult::Done(unparsed_data, None);
                } else {
                    chain!(
                        unparsed_data,
                        //Length.  We don't need this because we know how long the Vec is
                        length: le_u32~
                        mask: dbg!(call!(CrushRuleMask::parse))~
                        steps: dbg!(count!(call!(CrushRuleStep::parse), length as usize)),
                        ||{
                            Some(Rule{
                                mask: mask,
                                steps: steps,
                            })
                        }
                    )
                }
            }
            IResult::Incomplete(needed) => {
                return IResult::Incomplete(needed);
            }
            IResult::Error(e) => {
                return IResult::Error(e);
            }
        }
    }
    fn compile(&self) -> Result<Vec<u8>, EncodingError> {
        let mut buffer: Vec<u8> = Vec::new();
        // YES
        try!(buffer.write_u32::<LittleEndian>(1));

        try!(buffer.write_u32::<LittleEndian>(self.steps.len() as u32));
        buffer.extend(try!(self.mask.compile()));
        // Steps length
        for step in self.steps.iter() {
            buffer.extend(try!(step.compile()));
        }

        Ok(buffer)
    }
}

// Try to update the CrushRuleStep's now that we know the type_map.  I wish Ceph
// had included the type_map first in the compiled crush so I could skip this workaround.
pub fn update_rule_steps<'a>(rules: &'a mut Vec<Option<Rule>>,
                             type_map: &Vec<(i32, String)>)
                             -> &'a mut Vec<Option<Rule>> {
    for rule in rules.iter_mut() {
        match *rule {
            Some(ref mut r) => {
                for step in r.steps.iter_mut() {
                    step.update_arg_mapping(type_map)
                }
            }
            None => {
                // Skip None's
            }
        }
    }
    rules
}

pub fn update_buckets<'a>(crush_buckets: &'a mut Vec<BucketTypes>,
                          name_map: &Vec<(i32, String)>)
                          -> &'a mut Vec<BucketTypes> {
    for crush_bucket in crush_buckets.iter_mut() {
        match *crush_bucket {
            BucketTypes::Uniform(ref mut uniform) => {
                uniform.bucket.update_name_mapping(name_map);
            }
            BucketTypes::List(ref mut list) => {
                list.bucket.update_name_mapping(name_map);
            }
            BucketTypes::Tree(ref mut tree) => {
                tree.bucket.update_name_mapping(name_map);
            }
            BucketTypes::Straw(ref mut straw) => {
                straw.bucket.update_name_mapping(name_map);
            }
            BucketTypes::Straw2(ref mut straw) => {
                straw.bucket.update_name_mapping(name_map);
            }
            BucketTypes::Unknown => {}
        }
    }
    crush_buckets
}

impl fmt::Debug for CrushMap {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f,
            r#"CrushMap {{
                magic: {},
                max_buckets: {},
                max_rules: {},
                max_devices: {},
                buckets: {:?},
                rules: {:?},
                name_map: {:?},
                rule_name_map: {:?},
                choose_local_tries: {:?},
                choose_local_fallback_tries: {:?},
                choose_total_tries: {:?},
                chooseleaf_descend_once: {:?},
                chooseleaf_vary_r: {:?},
                straw_calc_version: {:?},
                allowed_bucket_algorithms: {:?},
                chooseleaf_stable: {:?},
            }}"#,
            self.magic,
            self.max_buckets,
            self.max_rules,
            self.max_devices,
            self.buckets,
            self.rules,
            self.name_map,
            self.rule_name_map,
            self.choose_local_tries,
            self.choose_local_fallback_tries,
            self.choose_total_tries,
            self.chooseleaf_descend_once,
            self.chooseleaf_vary_r,
            self.straw_calc_version,
            self.allowed_bucket_algorithms,
            self.chooseleaf_stable,
        )
    }
}

pub fn parse_crushmap<'a>(input: &'a [u8]) -> IResult<&[u8], CrushMap> {
    trace!("crushmap input: {:?}", input);
    chain!(
        input,
        //preamble
        crush_magic: le_u32 ~

        max_buckets: le_i32 ~
        max_rules: le_u32 ~
        max_devices: le_i32 ~

        buckets: dbg!(count!(
            call!(parse_bucket),
            max_buckets as usize
        ))~
        rules: dbg!(count!(
            call!(Rule::parse),
            max_rules as usize
        ))~
        type_map: call!(parse_string_map)~
        name_map: call!(parse_string_map)~
        rule_name_map: call!(parse_string_map)~

        //Tunables
        choose_local_tries: call!(try_le_u32)~
        choose_local_fallback_tries: call!(try_le_u32)~
        choose_total_tries: call!(try_le_u32)~
        chooseleaf_descend_once: call!(try_le_u32) ~
        chooseleaf_vary_r: call!(try_le_u8) ~
        straw_calc_version: call!(try_le_u8) ~
        allowed_bucket_algorithms: call!(try_le_u32) ~
        chooseleaf_stable: call!(try_le_u8),
        || {
            CrushMap{
                magic: crush_magic,
                max_buckets: max_buckets,
                max_rules: max_rules,
                max_devices: max_devices,

                buckets: buckets,
                rules: rules,
                type_map: type_map,
                name_map: name_map,
                rule_name_map: rule_name_map,

                choose_local_tries: choose_local_tries,
                choose_local_fallback_tries: choose_local_fallback_tries,
                choose_total_tries: choose_total_tries,
                chooseleaf_descend_once: chooseleaf_descend_once,
                chooseleaf_vary_r: chooseleaf_vary_r,
                straw_calc_version: straw_calc_version,
                allowed_bucket_algorithms: allowed_bucket_algorithms,
                chooseleaf_stable: chooseleaf_stable,
            }
        }
    )
}



pub fn decode_crushmap<'a>(input: &'a [u8]) -> Result<CrushMap, String> {
    let mut result = parse_crushmap(input);
    match result {
        IResult::Done(_, ref mut map) => {
            // Resolve the argument types
            update_rule_steps(&mut map.rules, &map.type_map);

            // Resolve the item names
            update_buckets(&mut map.buckets, &map.name_map);

            // TODO: Can we get rid of this clone?
            return Ok(map.clone());
        }
        IResult::Error(_) => Err("parsing error".to_string()),
        IResult::Incomplete(_) => Err("Incomplete".to_string()),
    }
}


pub fn encode_crushmap(crushmap: CrushMap) -> Result<Vec<u8>, EncodingError> {
    let mut buffer: Vec<u8> = Vec::new();
    try!(buffer.write_u32::<LittleEndian>(CRUSH_MAGIC));

    try!(buffer.write_i32::<LittleEndian>(crushmap.max_buckets));
    try!(buffer.write_u32::<LittleEndian>(crushmap.max_rules));
    try!(buffer.write_i32::<LittleEndian>(crushmap.max_devices));

    for bucket in crushmap.buckets.iter() {
        match bucket {
            &BucketTypes::Uniform(ref uniform) => {
                trace!("Trying to encode uniform bucket");
                buffer.extend(try!(uniform.compile()));
            }
            &BucketTypes::List(ref list) => {
                trace!("Trying to encode list bucket");
                buffer.extend(try!(list.compile()));
            }
            &BucketTypes::Tree(ref tree) => {
                trace!("Trying to encode tree bucket");
                buffer.extend(try!(tree.compile()));
            }
            &BucketTypes::Straw(ref straw) => {
                trace!("Trying to encode straw bucket");
                buffer.extend(try!(straw.compile()));
            }
            &BucketTypes::Straw2(ref straw) => {
                trace!("Trying to encode straw2 bucket");
                buffer.extend(try!(straw.compile()));
            }
            &BucketTypes::Unknown => {
                try!(buffer.write_u32::<LittleEndian>(0));
            }
        }
    }

    for rule in crushmap.rules.into_iter() {
        if rule.is_some() {
            let unwrapped_rule = rule.unwrap();
            buffer.extend(try!(unwrapped_rule.compile()));
        } else {
            // yes bits == 0
            try!(buffer.write_u32::<LittleEndian>(0));
        }
    }
    buffer.extend(try!(encode_string_map(crushmap.type_map)));
    buffer.extend(try!(encode_string_map(crushmap.name_map)));
    buffer.extend(try!(encode_string_map(crushmap.rule_name_map)));

    match crushmap.choose_local_tries {
        Some(val) => {
            try!(buffer.write_u32::<LittleEndian>(val));
        }
        None => {
            try!(buffer.write_u32::<LittleEndian>(0));
        }
    };

    match crushmap.choose_local_fallback_tries {
        Some(val) => {
            try!(buffer.write_u32::<LittleEndian>(val));
        }
        None => {
            try!(buffer.write_u32::<LittleEndian>(0));
        }
    };
    match crushmap.choose_total_tries {
        Some(val) => {
            try!(buffer.write_u32::<LittleEndian>(val));
        }
        None => {
            try!(buffer.write_u32::<LittleEndian>(0));
        }
    };
    match crushmap.chooseleaf_descend_once {
        Some(val) => {
            try!(buffer.write_u32::<LittleEndian>(val));
        }
        None => {
            try!(buffer.write_u32::<LittleEndian>(0));
        }
    };
    match crushmap.chooseleaf_vary_r {
        Some(val) => {
            try!(buffer.write_u8(val));
        }
        None => {
            try!(buffer.write_u8(0));
        }
    };
    match crushmap.straw_calc_version {
        Some(val) => {
            try!(buffer.write_u8(val));
        }
        None => {
            try!(buffer.write_u8(0));
        }
    };
    match crushmap.allowed_bucket_algorithms {
        Some(val) => {
            try!(buffer.write_u32::<LittleEndian>(val));
        }
        None => {
            try!(buffer.write_u32::<LittleEndian>(0));
        }
    };
    match crushmap.chooseleaf_stable {
        Some(val) => {
            try!(buffer.write_u8(val));
        }
        None => {
            try!(buffer.write_u8(0));
        }
    }

    Ok(buffer)
}