iscsi-client-rs 0.0.3

A pure-Rust iSCSI initiator library and CLI
Documentation 
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use anyhow::{Result, bail};

use crate::{
    client::pdu_connection::FromBytes,
    models::{
        common::{BasicHeaderSegment, HEADER_LEN, SendingData},
        opcode::{BhsOpcode, Opcode},
        text::common::StageFlags,
    },
};

/// BHS for NopOutRequest PDU
#[repr(C)]
#[derive(Debug, Default, PartialEq)]
pub struct TextResponse {
    pub opcode: BhsOpcode,            // 0
    pub flags: StageFlags,            // 1
    reserved1: [u8; 2],               // 2..4
    pub total_ahs_length: u8,         // 4
    pub data_segment_length: [u8; 3], // 5..8
    pub lun: [u8; 8],                 // 8..16
    pub initiator_task_tag: u32,      // 16..20
    pub target_task_tag: u32,         // 20..24
    pub stat_sn: u32,                 // 24..28
    pub exp_cmd_sn: u32,              // 28..32
    pub max_cmd_sn: u32,              // 32..36
    reserved2: [u8; 16],              // 36..48
}

impl TextResponse {
    /// Serialize BHS in 48 bytes
    pub fn to_bhs_bytes(&self) -> [u8; HEADER_LEN] {
        let mut buf = [0u8; HEADER_LEN];
        buf[0] = (&self.opcode).into();
        buf[1] = self.flags.bits();
        buf[2..4].copy_from_slice(&self.reserved1);
        buf[4] = self.total_ahs_length;
        buf[5..8].copy_from_slice(&self.data_segment_length);
        buf[8..16].copy_from_slice(&self.lun);
        buf[16..20].copy_from_slice(&self.initiator_task_tag.to_be_bytes());
        buf[20..24].copy_from_slice(&self.target_task_tag.to_be_bytes());
        buf[24..28].copy_from_slice(&self.stat_sn.to_be_bytes());
        buf[28..32].copy_from_slice(&self.exp_cmd_sn.to_be_bytes());
        buf[32..36].copy_from_slice(&self.max_cmd_sn.to_be_bytes());
        // buf[36..48] -- reserved
        buf
    }

    pub fn from_bhs_bytes(buf: &[u8]) -> Result<Self, anyhow::Error> {
        if buf.len() < HEADER_LEN {
            bail!("buffer too small");
        }
        let opcode = BhsOpcode::try_from(buf[0])?;
        if opcode.opcode != Opcode::TextResp {
            bail!("TextResp invalid opcode: {:?}", opcode.opcode);
        }
        let flags = StageFlags::try_from(buf[1])?;
        let total_ahs_length = buf[4];
        let data_segment_length = [buf[5], buf[6], buf[7]];
        let mut lun = [0u8; 8];
        lun.clone_from_slice(&buf[8..16]);
        let initiator_task_tag = u32::from_be_bytes(buf[16..20].try_into()?);
        let target_task_tag = u32::from_be_bytes(buf[20..24].try_into()?);
        let stat_sn = u32::from_be_bytes(buf[24..28].try_into()?);
        let exp_cmd_sn = u32::from_be_bytes(buf[28..32].try_into()?);
        let max_cmd_sn = u32::from_be_bytes(buf[32..36].try_into()?);
        // buf[32..44] -- reserved
        Ok(TextResponse {
            opcode,
            flags,
            reserved1: [0u8; 2],
            total_ahs_length,
            lun,
            data_segment_length,
            initiator_task_tag,
            target_task_tag,
            stat_sn,
            exp_cmd_sn,
            max_cmd_sn,
            reserved2: [0u8; 16],
        })
    }
}

impl SendingData for TextResponse {
    fn get_final_bit(&self) -> bool {
        self.flags.contains(StageFlags::FINAL)
    }

    fn set_final_bit(&mut self) {
        // F ← 1,  C ← 0
        self.flags.remove(StageFlags::CONTINUE);
        self.flags.insert(StageFlags::FINAL);
    }

    fn get_continue_bit(&self) -> bool {
        self.flags.contains(StageFlags::CONTINUE)
    }

    fn set_continue_bit(&mut self) {
        // C ← 1,  F ← 0
        self.flags.remove(StageFlags::FINAL);
        self.flags.insert(StageFlags::CONTINUE);
    }
}

impl FromBytes for TextResponse {
    fn from_bhs_bytes(bytes: &[u8]) -> Result<Self> {
        Self::from_bhs_bytes(bytes)
    }
}

impl BasicHeaderSegment for TextResponse {
    fn to_bhs_bytes(&self) -> Result<[u8; HEADER_LEN]> {
        Ok(self.to_bhs_bytes())
    }

    fn get_opcode(&self) -> &BhsOpcode {
        &self.opcode
    }

    fn get_initiator_task_tag(&self) -> u32 {
        self.initiator_task_tag
    }

    fn get_ahs_length_bytes(&self) -> usize {
        (self.total_ahs_length as usize) * 4
    }

    fn set_ahs_length_bytes(&mut self, len: u8) {
        self.total_ahs_length = len >> 2;
    }

    fn get_data_length_bytes(&self) -> usize {
        u32::from_be_bytes([
            0,
            self.data_segment_length[0],
            self.data_segment_length[1],
            self.data_segment_length[2],
        ]) as usize
    }

    fn set_data_length_bytes(&mut self, len: u32) {
        let be = len.to_be_bytes();
        self.data_segment_length = [be[1], be[2], be[3]];
    }
}