Ported all NUS download functions from libWiiPy and corresponding CLI commands

Also adds the basics of U8 archive packing/unpacking, however they are not in a usable state yet and there are no working CLI commands associated with them.

Cargo.toml

@@ -35,3 +35,4 @@ regex = "1"
 clap = { version = "4", features = ["derive"] }
 anyhow = "1"
 thiserror = "2"
+reqwest = { version = "0", features = ["blocking"] }

src/archive/u8.rs

@@ -3,3 +3,206 @@
 //
 // Implements the structures and methods required for parsing U8 archives.
 
+use std::io::{Cursor, Read, Seek, SeekFrom, Write};
+use std::path::Path;
+use byteorder::{BigEndian, ReadBytesExt, WriteBytesExt};
+use thiserror::Error;
+
+#[derive(Debug, Error)]
+pub enum U8Error {
+    #[error("invalid file name at offset {0}")]
+    InvalidFileName(u64),
+    #[error("this does not appear to be a U8 archive (missing magic number)")]
+    NotU8Data,
+    #[error("U8 data is not in a valid format")]
+    IO(#[from] std::io::Error),
+}
+
+#[derive(Clone, Debug)]
+struct U8Node {
+    node_type: u8,
+    name_offset: u32, // This is really type u24, so the most significant byte will be ignored.
+    data_offset: u32,
+    size: u32,
+}
+
+#[derive(Debug)]
+pub struct U8Archive {
+    u8_nodes: Vec<U8Node>,
+    file_names: Vec<String>,
+    file_data: Vec<Vec<u8>>,
+    root_node_offset: u32,
+    header_size: u32,
+    data_offset: u32,
+    padding: [u8; 16],
+}
+
+impl U8Archive {
+    /// Creates a new U8 instance from the binary data of a U8 file.
+    pub fn from_bytes(data: &[u8]) -> Result<Self, U8Error> {
+        let mut buf = Cursor::new(data);
+        let mut magic = [0u8; 4];
+        buf.read_exact(&mut magic)?;
+        // Check for an IMET header if the magic number isn't the correct value before throwing an
+        // error.
+        if &magic != b"\x55\xAA\x38\x2D" {
+            // Check for an IMET header immediately at the start of the file.
+            buf.seek(SeekFrom::Start(0x40))?;
+            buf.read_exact(&mut magic)?;
+            if &magic == b"\x49\x4D\x45\x54" {
+                // IMET with no build tag means the U8 archive should start at 0x600.
+                buf.seek(SeekFrom::Start(0x600))?;
+                buf.read_exact(&mut magic)?;
+                if &magic != b"\x55\xAA\x38\x2D" {
+                    return Err(U8Error::NotU8Data);
+                }
+                println!("ignoring IMET header at 0x40");
+            }
+            // Check for an IMET header that comes after a built tag.
+            else {
+                buf.seek(SeekFrom::Start(0x80))?;
+                buf.read_exact(&mut magic)?;
+                if &magic == b"\x49\x4D\x45\x54" {
+                    // IMET with a build tag means the U8 archive should start at 0x600.
+                    buf.seek(SeekFrom::Start(0x640))?;
+                    buf.read_exact(&mut magic)?;
+                    if &magic != b"\x55\xAA\x38\x2D" {
+                        return Err(U8Error::NotU8Data);
+                    }
+                    println!("ignoring IMET header at 0x80");
+                }
+            }
+        }
+        let root_node_offset = buf.read_u32::<BigEndian>()?;
+        let header_size = buf.read_u32::<BigEndian>()?;
+        let data_offset = buf.read_u32::<BigEndian>()?;
+        let mut padding = [0u8; 16];
+        buf.read_exact(&mut padding)?;
+        // Manually read the root node, since we need its size anyway to know how many nodes there
+        // are total.
+        let root_node_type = buf.read_u8()?;
+        let root_node_name_offset = buf.read_u24::<BigEndian>()?;
+        let root_node_data_offset = buf.read_u32::<BigEndian>()?;
+        let root_node_size = buf.read_u32::<BigEndian>()?;
+        let root_node = U8Node {
+            node_type: root_node_type,
+            name_offset: root_node_name_offset,
+            data_offset: root_node_data_offset,
+            size: root_node_size,
+        };
+        // Create a vec of nodes, push the root node, and then iterate over the remaining number
+        // of nodes in the file and push them to the vec.
+        let mut u8_nodes: Vec<U8Node> = Vec::new();
+        u8_nodes.push(root_node);
+        for _ in 1..root_node_size {
+            let node_type = buf.read_u8()?;
+            let name_offset = buf.read_u24::<BigEndian>()?;
+            let data_offset = buf.read_u32::<BigEndian>()?;
+            let size = buf.read_u32::<BigEndian>()?;
+            u8_nodes.push(U8Node { node_type, name_offset, data_offset, size })
+        }
+        // Iterate over the loaded nodes and load the file names and data associated with them.
+        let base_name_offset = buf.position();
+        let mut file_names = Vec::<String>::new();
+        let mut file_data = Vec::<Vec<u8>>::new();
+        for node in &u8_nodes {
+            buf.seek(SeekFrom::Start(base_name_offset + node.name_offset as u64))?;
+            let mut name_bin = Vec::<u8>::new();
+            // Read the file name one byte at a time until we find a null byte.
+            loop {
+                let byte = buf.read_u8()?;
+                if byte == b'\0' {
+                    break;
+                }
+                name_bin.push(byte);
+            }
+            file_names.push(String::from_utf8(name_bin).map_err(|_| U8Error::InvalidFileName(base_name_offset + node.name_offset as u64))?.to_owned());
+            // If this is a file node, read the data for the file.
+            if node.node_type == 0 {
+                buf.seek(SeekFrom::Start(node.data_offset as u64))?;
+                let mut data = vec![0u8; node.size as usize];
+                buf.read_exact(&mut data)?;
+                file_data.push(data);
+            } else {
+                file_data.push(Vec::new());
+            }
+        }
+        Ok(U8Archive {
+            u8_nodes,
+            file_names,
+            file_data,
+            root_node_offset,
+            header_size,
+            data_offset,
+            padding,
+        })
+    }
+
+    fn pack_dir() {
+        todo!();
+    }
+
+    pub fn from_dir(_input: &Path) -> Result<Self, U8Error> {
+        todo!();
+    }
+
+    /// Dumps the data in a U8Archive instance back into binary data that can be written to a file.
+    pub fn to_bytes(&self) -> Result<Vec<u8>, U8Error> {
+        // Header size starts at 0 because the header size starts with the nodes and does not
+        // include the actual file header.
+        let mut header_size: u32 = 0;
+        // Add 12 bytes for each node, since that's how many bytes each one is made up of.
+        for _ in 0..self.u8_nodes.len() {
+            header_size += 12;
+        }
+        // Add the number of bytes used for each file/folder name in the string table.
+        for file_name in &self.file_names {
+            header_size += file_name.len() as u32 + 1
+        }
+        // The initial data offset is equal to the file header (32 bytes) + node data aligned to
+        // 64 bytes.
+        let data_offset: u32 = (header_size + 32 + 63) & !63;
+        // Adjust all nodes to place file data in the same order as the nodes. For some reason
+        // Nintendo-made U8 archives don't necessarily do this?
+        let mut current_data_offset = data_offset;
+        let mut current_name_offset: u32 = 0;
+        let mut u8_nodes = self.u8_nodes.clone();
+        for i in 0..u8_nodes.len() {
+            if u8_nodes[i].node_type == 0 {
+                u8_nodes[i].data_offset = (current_data_offset + 31) & !31;
+                current_data_offset += (u8_nodes[i].size + 31) & !31;
+            }
+            // Calculate the name offsets, including the extra 1 for the NULL byte.
+            u8_nodes[i].name_offset = current_name_offset;
+            current_name_offset += self.file_names[i].len() as u32 + 1
+        }
+        // Begin writing file data.
+        let mut buf: Vec<u8> = Vec::new();
+        buf.write_all(b"\x55\xAA\x38\x2D")?;
+        buf.write_u32::<BigEndian>(0x20)?; // The root node offset is always 0x20.
+        buf.write_u32::<BigEndian>(header_size)?;
+        buf.write_u32::<BigEndian>(data_offset)?;
+        buf.write_all(&self.padding)?;
+        // Iterate over nodes and write them out.
+        for node in &u8_nodes {
+            buf.write_u8(node.node_type)?;
+            buf.write_u24::<BigEndian>(node.name_offset)?;
+            buf.write_u32::<BigEndian>(node.data_offset)?;
+            buf.write_u32::<BigEndian>(node.size)?;
+        }
+        // Iterate over file names with a null byte at the end.
+        for file_name in &self.file_names {
+            buf.write_all(file_name.as_bytes())?;
+            buf.write_u8(b'\0')?;
+        }
+        // Pad to the nearest multiple of 64 bytes.
+        buf.resize((buf.len() + 63) & !63, 0);
+        // Iterate over the file data and dump it. The file needs to be aligned to 32 bytes after
+        // each write.
+        for data in &self.file_data {
+            buf.write_all(data)?;
+            buf.resize((buf.len() + 31) & !31, 0);
+        }
+        Ok(buf)
+    }
+}

src/bin/rustii/archive/mod.rs

@@ -3,3 +3,4 @@
 
 pub mod ash;
 pub mod lz77;
+pub mod u8;

src/bin/rustii/archive/u8.rs

@@ -0,0 +1,44 @@
+// archive/u8.rs from rustii (c) 2025 NinjaCheetah & Contributors
+// https://github.com/NinjaCheetah/rustii
+//
+// Code for the U8 packing/unpacking commands in the rustii CLI.
+
+use std::{str, fs};
+use std::path::{Path, PathBuf};
+use anyhow::{bail, Context, Result};
+use clap::Subcommand;
+use rustii::archive::u8;
+
+#[derive(Subcommand)]
+#[command(arg_required_else_help = true)]
+pub enum Commands {
+    /// Pack a directory into a U8 archive
+    Pack {
+        /// The directory to pack into a U8 archive
+        input: String,
+        /// The name of the packed U8 archive
+        output: String,
+    },
+    /// Unpack a U8 archive into a directory
+    Unpack {
+        /// The path to the U8 archive to unpack
+        input: String,
+        /// The directory to unpack the U8 archive to
+        output: String,
+    }
+}
+
+pub fn pack_u8_archive(_input: &str, _output: &str) -> Result<()> {
+    todo!();
+}
+
+pub fn unpack_u8_archive(input: &str, output: &str) -> Result<()> {
+    let in_path = Path::new(input);
+    if !in_path.exists() {
+        bail!("Source U8 archive \"{}\" could not be found.", input);
+    }
+    let u8_data = u8::U8Archive::from_bytes(&fs::read(in_path)?)?;
+    println!("{:?}", u8_data);
+    fs::write(Path::new(output), u8_data.to_bytes()?)?;
+    Ok(())
+}

src/bin/rustii/main.rs

@@ -44,6 +44,14 @@ enum Commands {
         #[command(subcommand)]
         command: archive::lz77::Commands
     },
+    Nus {
+        #[command(subcommand)]
+        command: title::nus::Commands
+    },
+    U8 {
+        #[command(subcommand)]
+        command: archive::u8::Commands
+    },
     /// Pack/unpack/edit a WAD file
     Wad {
         #[command(subcommand)]
@@ -68,6 +76,9 @@ fn main() -> Result<()> {
         Some(Commands::Fakesign { input, output }) => {
             title::fakesign::fakesign(input, output)?
         },
+        Some(Commands::Info { input }) => {
+            info::info(input)?
+        },
         Some(Commands::Lz77 { command }) => {
             match command {
                 archive::lz77::Commands::Compress { input, output } => {
@@ -78,8 +89,28 @@ fn main() -> Result<()> {
                 }
             }
         },
-        Some(Commands::Info { input }) => {
-            info::info(input)?
+        Some(Commands::Nus { command }) => {
+            match command {
+                title::nus::Commands::Ticket { tid, output } => {
+                    title::nus::download_ticket(tid, output)?  
+                },
+                title::nus::Commands::Title { tid, version, output} => {
+                    title::nus::download_title(tid, version, output)?
+                }
+                title::nus::Commands::Tmd { tid, version, output} => {
+                    title::nus::download_tmd(tid, version, output)?
+                }
+            }
+        }
+        Some(Commands::U8 { command }) => {
+            match command {
+                archive::u8::Commands::Pack { input, output } => {
+                    archive::u8::pack_u8_archive(input, output)?
+                },
+                archive::u8::Commands::Unpack { input, output } => {
+                    archive::u8::unpack_u8_archive(input, output)?
+                }
+            }
         },
         Some(Commands::Wad { command }) => {
             match command {

src/bin/rustii/title/mod.rs

@@ -2,4 +2,5 @@
 // https://github.com/NinjaCheetah/rustii
 
 pub mod fakesign;
+pub mod nus;
 pub mod wad;

src/bin/rustii/title/nus.rs

@@ -0,0 +1,215 @@
+// title/nus.rs from rustii (c) 2025 NinjaCheetah & Contributors
+// https://github.com/NinjaCheetah/rustii
+//
+// Code for NUS-related commands in the rustii CLI.
+
+use std::{str, fs};
+use std::path::PathBuf;
+use anyhow::{bail, Context, Result};
+use clap::{Subcommand, Args};
+use rustii::title::{cert, content, nus, ticket, tmd};
+use rustii::title;
+
+#[derive(Subcommand)]
+#[command(arg_required_else_help = true)]
+pub enum Commands {
+    /// Download a Ticket from the NUS
+    Ticket {
+        /// The Title ID that the Ticket is for
+        tid: String,
+        /// An optional Ticket name; defaults to <tid>.tik
+        #[arg(short, long)]
+        output: Option<String>,
+    },
+    /// Download a title from the NUS
+    Title {
+        /// The Title ID of the Title to download
+        tid: String,
+        /// The version of the Title to download
+        #[arg(short, long)]
+        version: Option<String>,
+        #[command(flatten)]
+        output: TitleOutputType,
+    },
+    /// Download a TMD from the NUS
+    Tmd {
+        /// The Title ID that the TMD is for
+        tid: String,
+        /// The version of the TMD to download
+        #[arg(short, long)]
+        version: Option<String>,
+        /// An optional TMD name; defaults to <tid>.tmd
+        #[arg(short, long)]
+        output: Option<String>,
+    }
+}
+
+#[derive(Args)]
+#[clap(next_help_heading = "Output Format")]
+#[group(multiple = false, required = true)]
+pub struct TitleOutputType {
+    /// Download the Title data to the specified output directory
+    #[arg(short, long)]
+    output: Option<String>,
+    /// Download the Title to a WAD file
+    #[arg(short, long)]
+    wad: Option<String>,
+}
+
+pub fn download_ticket(tid: &str, output: &Option<String>) -> Result<()> {
+    println!("Downloading Ticket for title {tid}...");
+    if tid.len() != 16 {
+        bail!("The specified Title ID is invalid!");
+    }
+    let out_path = if output.is_some() {
+        PathBuf::from(output.clone().unwrap())
+    } else {
+        PathBuf::from(format!("{}.tik", tid))
+    };
+    let tid: [u8; 8] = hex::decode(tid)?.try_into().unwrap();
+    let tik_data = nus::download_ticket(tid, true).with_context(|| "Ticket data could not be downloaded.")?;
+    fs::write(&out_path, tik_data)?;
+    println!("Successfully downloaded Ticket to \"{}\"!", out_path.display());
+    Ok(())
+}
+
+fn download_title_dir(title: title::Title, output: String) -> Result<()> {
+    println!(" - Saving downloaded data...");
+    let out_path = PathBuf::from(output);
+    if out_path.exists() {
+        if !out_path.is_dir() {
+            bail!("A file already exists with the specified directory name!");
+        }
+    } else {
+        fs::create_dir(&out_path).with_context(|| format!("The output directory \"{}\" could not be created.", out_path.display()))?;
+    }
+    let tid = hex::encode(title.tmd.title_id);
+    println!("  - Saving TMD...");
+    fs::write(out_path.join(format!("{}.tmd", &tid)), title.tmd.to_bytes()?).with_context(|| format!("Failed to open TMD file \"{}.tmd\" for writing.", tid))?;
+    println!("  - Saving Ticket...");
+    fs::write(out_path.join(format!("{}.tik", &tid)), title.ticket.to_bytes()?).with_context(|| format!("Failed to open Ticket file \"{}.tmd\" for writing.", tid))?;
+    println!("  - Saving certificate chain...");
+    fs::write(out_path.join(format!("{}.cert", &tid)), title.cert_chain.to_bytes()?).with_context(|| format!("Failed to open certificate chain file \"{}.cert\" for writing.", tid))?;
+    // Iterate over the content files and write them out in encrypted form.
+    for record in &title.content.content_records {
+        println!("  - Decrypting and saving content with Content ID {}...", record.content_id);
+        fs::write(out_path.join(format!("{:08X}.app", record.content_id)), title.get_content_by_cid(record.content_id)?)
+            .with_context(|| format!("Failed to open content file \"{:08X}.app\" for writing.", record.content_id))?;
+    }
+    println!("Successfully downloaded title with Title ID {} to directory \"{}\"!", tid, out_path.display());
+    Ok(())
+}
+
+fn download_title_dir_enc(tmd: tmd::TMD, content_region: content::ContentRegion, cert_chain: cert::CertificateChain, output: String) -> Result<()> {
+    println!(" - Saving downloaded data...");
+    let out_path = PathBuf::from(output);
+    if out_path.exists() {
+        if !out_path.is_dir() {
+            bail!("A file already exists with the specified directory name!");
+        }
+    } else {
+        fs::create_dir(&out_path).with_context(|| format!("The output directory \"{}\" could not be created.", out_path.display()))?;
+    }
+    let tid = hex::encode(tmd.title_id);
+    println!("  - Saving TMD...");
+    fs::write(out_path.join(format!("{}.tmd", &tid)), tmd.to_bytes()?).with_context(|| format!("Failed to open TMD file \"{}.tmd\" for writing.", tid))?;
+    println!("  - Saving certificate chain...");
+    fs::write(out_path.join(format!("{}.cert", &tid)), cert_chain.to_bytes()?).with_context(|| format!("Failed to open certificate chain file \"{}.cert\" for writing.", tid))?;
+    // Iterate over the content files and write them out in encrypted form.
+    for record in &content_region.content_records {
+        println!("  - Saving content with Content ID {}...", record.content_id);
+        fs::write(out_path.join(format!("{:08X}", record.content_id)), content_region.get_enc_content_by_cid(record.content_id)?)
+            .with_context(|| format!("Failed to open content file \"{:08X}\" for writing.", record.content_id))?;
+    }
+    println!("Successfully downloaded title with Title ID {} to directory \"{}\"!", tid, out_path.display());
+    Ok(())
+}
+
+fn download_title_wad(title: title::Title, output: String) -> Result<()> {
+    println!(" - Packing WAD...");
+    let out_path = PathBuf::from(output).with_extension("wad");
+    fs::write(&out_path, title.to_wad().with_context(|| "A WAD could not be packed.")?.to_bytes()?).with_context(|| format!("Could not open WAD file \"{}\" for writing.", out_path.display()))?;
+    println!("Successfully downloaded title with Title ID {} to WAD file \"{}\"!", hex::encode(title.tmd.title_id), out_path.display());
+    Ok(())
+}
+
+pub fn download_title(tid: &str, version: &Option<String>, output: &TitleOutputType) -> Result<()> {
+    if tid.len() != 16 {
+        bail!("The specified Title ID is invalid!");
+    }
+    if version.is_some() {
+        println!("Downloading title {} v{}, please wait...", tid, version.clone().unwrap());
+    } else {
+        println!("Downloading title {} vLatest, please wait...", tid);
+    }
+    let version: Option<u16> = if version.is_some() {
+        Some(version.clone().unwrap().parse().with_context(|| "The specified Title version must be a valid integer!")?)
+    } else {
+        None
+    };
+    let tid: [u8; 8] = hex::decode(tid)?.try_into().unwrap();
+    println!(" - Downloading and parsing TMD...");
+    let tmd = tmd::TMD::from_bytes(&nus::download_tmd(tid, version, true).with_context(|| "TMD data could not be downloaded.")?)?;
+    println!(" - Downloading and parsing Ticket...");
+    let tik_res = &nus::download_ticket(tid, true);
+    let tik = match tik_res {
+        Ok(tik) => Some(ticket::Ticket::from_bytes(tik)?),
+        Err(_) => {
+            if output.wad.is_some() {
+                bail!("--wad was specified, but this Title has no common Ticket and cannot be packed into a WAD!");
+            } else {
+                println!("  - No Ticket is available!");
+                None
+            }
+        }
+    };
+    // Build a vec of contents by iterating over the content records and downloading each one.
+    let mut contents: Vec<Vec<u8>> = Vec::new();
+    for record in &tmd.content_records {
+        println!(" - Downloading content {} of {} (Content ID: {}, Size: {} bytes)...",
+            record.index + 1, &tmd.content_records.len(), record.content_id, record.content_size);
+        contents.push(nus::download_content(tid, record.content_id, true).with_context(|| format!("Content with Content ID {} could not be downloaded.", record.content_id))?);
+        println!("   - Done!");
+    }
+    let content_region = content::ContentRegion::from_contents(contents, tmd.content_records.clone())?;
+    println!(" - Building certificate chain...");
+    let cert_chain = cert::CertificateChain::from_bytes(&nus::download_cert_chain(true).with_context(|| "Certificate chain could not be built.")?)?;
+    if tik.is_some() {
+        // If we have a Ticket, then build a Title and jump to the output method.
+        let title = title::Title::from_parts(cert_chain, None, tik.unwrap(), tmd, content_region, None)?;
+        if output.wad.is_some() {
+            download_title_wad(title, output.wad.clone().unwrap())?;
+        } else {
+            download_title_dir(title, output.output.clone().unwrap())?;
+        }
+    } else {
+        // If we're downloading to a directory and have no Ticket, save the TMD and encrypted
+        // contents to the directory only.
+        download_title_dir_enc(tmd, content_region, cert_chain, output.output.clone().unwrap())?;
+    }
+    Ok(())
+}
+
+pub fn download_tmd(tid: &str, version: &Option<String>, output: &Option<String>) -> Result<()> {
+    let version: Option<u16> = if version.is_some() {
+        Some(version.clone().unwrap().parse().with_context(|| "The specified TMD version must be a valid integer!")?)
+    } else {
+        None
+    };
+    println!("Downloading TMD for title {tid}...");
+    if tid.len() != 16 {
+        bail!("The specified Title ID is invalid!");
+    }
+    let out_path = if output.is_some() {
+        PathBuf::from(output.clone().unwrap())
+    } else if version.is_some() {
+        PathBuf::from(format!("{}.tmd.{}", tid, version.unwrap()))
+    } else {
+        PathBuf::from(format!("{}.tmd", tid))
+    };
+    let tid: [u8; 8] = hex::decode(tid)?.try_into().unwrap();
+    let tmd_data = nus::download_tmd(tid, version, true).with_context(|| "TMD data could not be downloaded.")?;
+    fs::write(&out_path, tmd_data)?;
+    println!("Successfully downloaded TMD to \"{}\"!", out_path.display());
+    Ok(())
+}

src/bin/rustii/title/wad.rs

@@ -138,7 +138,7 @@ pub fn convert_wad(input: &str, target: &ConvertTargets, output: &Option<String>
     }
     title.ticket.title_key = title_key_new;
     title.fakesign()?;
-    fs::write(out_path.clone(), title.to_wad()?.to_bytes()?)?;
+    fs::write(&out_path, title.to_wad()?.to_bytes()?)?;
     println!("Successfully converted {} WAD to {} WAD \"{}\"!", source, target, out_path.file_name().unwrap().to_str().unwrap());
     Ok(())
 }
@@ -205,7 +205,7 @@ pub fn pack_wad(input: &str, output: &str) -> Result<()> {
             out_path.set_extension("wad");
         }
     }
-    fs::write(out_path.clone(), wad.to_bytes()?).with_context(|| format!("Could not open output file \"{}\" for writing.", out_path.display()))?;
+    fs::write(&out_path, wad.to_bytes()?).with_context(|| format!("Could not open output file \"{}\" for writing.", out_path.display()))?;
     println!("WAD file packed!");
     Ok(())
 }

src/title/content.rs

@@ -6,6 +6,7 @@
 use std::io::{Cursor, Read, Seek, SeekFrom, Write};
 use sha1::{Sha1, Digest};
 use thiserror::Error;
+use crate::title::content::ContentError::MissingContents;
 use crate::title::tmd::ContentRecord;
 use crate::title::crypto;
 
@@ -13,6 +14,8 @@ use crate::title::crypto;
 pub enum ContentError {
     #[error("requested index {index} is out of range (must not exceed {max})")]
     IndexOutOfRange { index: usize, max: usize },
+    #[error("expected {required} contents based on content records but found {found}")]
+    MissingContents { required: usize, found: usize },
     #[error("content with requested Content ID {0} could not be found")]
     CIDNotFound(u32),
     #[error("content's hash did not match the expected value (was {hash}, expected {expected})")]
@@ -71,15 +74,27 @@ impl ContentRegion {
         })
     }
 
+    /// Creates a ContentRegion instance that can be used to parse and edit content stored in a 
+    /// digital Wii title from a vector of contents and the ContentRecords from a TMD.
+    pub fn from_contents(contents: Vec<Vec<u8>>, content_records: Vec<ContentRecord>) -> Result<Self, ContentError> {
+        if contents.len() != content_records.len() {
+            return Err(MissingContents { required: content_records.len(), found: contents.len()});
+        }
+        let mut content_region = Self::new(content_records)?;
+        for i in 0..contents.len() {
+            content_region.load_enc_content(&contents[i], content_region.content_records[i].index as usize)?;
+        }
+        Ok(content_region)
+    }
+    
     /// Creates a ContentRegion instance from the ContentRecords of a TMD that contains no actual
     /// content. This can be used to load existing content from files.
     pub fn new(content_records: Vec<ContentRecord>) -> Result<Self, ContentError> {
         let content_region_size: u64 = content_records.iter().map(|x| (x.content_size + 63) & !63).sum();
         let content_region_size = content_region_size as u32;
         let num_contents = content_records.len() as u16;
-        let content_start_offsets: Vec<u64> = Vec::new();
-        let mut contents: Vec<Vec<u8>> = Vec::new();
-        contents.resize(num_contents as usize, Vec::new());
+        let content_start_offsets: Vec<u64> = vec![0; num_contents as usize];
+        let contents: Vec<Vec<u8>> = vec![Vec::new(); num_contents as usize];
         Ok(ContentRegion {
             content_records,
             content_region_size,
@@ -144,6 +159,16 @@ impl ContentRegion {
         }
     }
 
+    /// Loads existing content into the specified index of a ContentRegion instance. This content 
+    /// must be encrypted.
+    pub fn load_enc_content(&mut self, content: &[u8], index: usize) -> Result<(), ContentError> {
+        if index >= self.content_records.len() {
+            return Err(ContentError::IndexOutOfRange { index, max: self.content_records.len() - 1 });
+        }
+        self.contents[index] = Vec::from(content);
+        Ok(())
+    }
+    
     /// Loads existing content into the specified index of a ContentRegion instance. This content 
     /// must be decrypted and needs to match the size and hash listed in the content record at that
     /// index.

src/title/mod.rs

@@ -7,6 +7,7 @@ pub mod cert;
 pub mod commonkeys;
 pub mod content;
 pub mod crypto;
+pub mod nus;
 pub mod ticket;
 pub mod tmd;
 pub mod versions;
@@ -52,15 +53,37 @@ impl Title {
         let ticket = ticket::Ticket::from_bytes(&wad.ticket()).map_err(TitleError::Ticket)?;
         let tmd = tmd::TMD::from_bytes(&wad.tmd()).map_err(TitleError::TMD)?;
         let content = content::ContentRegion::from_bytes(&wad.content(), tmd.content_records.clone()).map_err(TitleError::Content)?;
-        let title = Title {
+        Ok(Title {
             cert_chain,
             crl: wad.crl(),
             ticket,
             tmd,
             content,
             meta: wad.meta(),
+        })
+    }
+    
+    /// Creates a new Title instance from all of its individual components.
+    pub fn from_parts(cert_chain: cert::CertificateChain, crl: Option<&[u8]>, ticket: ticket::Ticket, tmd: tmd::TMD,
+                      content: content::ContentRegion, meta: Option<&[u8]>) -> Result<Title, TitleError> {
+        // Create empty vecs for the CRL and meta areas if we weren't supplied with any, as they're
+        // optional components.
+        let crl = match crl {
+            Some(crl) => crl.to_vec(),
+            None => Vec::new()
         };
-        Ok(title)
+        let meta = match meta {
+            Some(meta) => meta.to_vec(),
+            None => Vec::new()
+        };
+        Ok(Title {
+            cert_chain,
+            crl,
+            ticket,
+            tmd,
+            content,
+            meta
+        })
     }
     
     /// Converts a Title instance into a WAD, which can be used to export the Title back to a file.

src/title/nus.rs

@@ -0,0 +1,143 @@
+// title/nus.rs from rustii (c) 2025 NinjaCheetah & Contributors
+// https://github.com/NinjaCheetah/rustii
+//
+// Implements the functions required for downloading data from the NUS.
+
+use std::str;
+use std::io::Write;
+use reqwest;
+use thiserror::Error;
+use crate::title::{cert, tmd, ticket, content};
+use crate::title;
+
+use sha1::{Sha1, Digest};
+
+const WII_NUS_ENDPOINT: &str = "http://nus.cdn.shop.wii.com/ccs/download/";
+const WII_U_NUS_ENDPOINT: &str = "http://ccs.cdn.wup.shop.nintendo.net/ccs/download/";
+
+#[derive(Debug, Error)]
+pub enum NUSError {
+    #[error("the data returned by the NUS is not valid")]
+    InvalidData,
+    #[error("the requested Title ID or version could not be found on the NUS")]
+    NotFound,
+    #[error("Certificate processing error")]
+    Certificate(#[from] cert::CertificateError),
+    #[error("TMD processing error")]
+    TMD(#[from] tmd::TMDError),
+    #[error("Ticket processing error")]
+    Ticket(#[from] ticket::TicketError),
+    #[error("Content processing error")]
+    Content(#[from] content::ContentError),
+    #[error("an error occurred while assembling a Title from the downloaded data")]
+    Title(#[from] title::TitleError),
+    #[error("data could not be downloaded from the NUS")]
+    Request(#[from] reqwest::Error),
+    #[error("an error occurred writing NUS data")]
+    IO(#[from] std::io::Error),
+}
+
+/// Downloads the retail certificate chain from the NUS.
+pub fn download_cert_chain(wiiu_endpoint: bool) -> Result<Vec<u8>, NUSError> {
+    // To build the certificate chain, we need to download both the TMD and Ticket of a title. For
+    // the sake of simplicity, we'll use the Wii Menu 4.3U because I already found the required TMD
+    // and Ticket offsets for it.
+    let endpoint_url = if wiiu_endpoint {
+        WII_U_NUS_ENDPOINT.to_owned()
+    } else {
+        WII_NUS_ENDPOINT.to_owned()
+    };
+    let tmd_url = format!("{}0000000100000002/tmd.513", endpoint_url);
+    let tik_url = format!("{}0000000100000002/cetk", endpoint_url);
+    let client = reqwest::blocking::Client::new();
+    let tmd = client.get(tmd_url).header(reqwest::header::USER_AGENT, "wii libnup/1.0").send()?.bytes()?;
+    let tik = client.get(tik_url).header(reqwest::header::USER_AGENT, "wii libnup/1.0").send()?.bytes()?;
+    // Assemble the certificate chain.
+    let mut cert_chain: Vec<u8> = Vec::new();
+    // Certificate Authority data.
+    cert_chain.write_all(&tik[0x2A4 + 768..])?;
+    // Certificate Policy (TMD certificate) data.
+    cert_chain.write_all(&tmd[0x328..0x328 + 768])?;
+    // XS (Ticket certificate) data.
+    cert_chain.write_all(&tik[0x2A4..0x2A4 + 768])?;
+    Ok(cert_chain)
+}
+
+/// Downloads a specified content file from the specified title from the NUS.
+pub fn download_content(title_id: [u8; 8], content_id: u32, wiiu_endpoint: bool) -> Result<Vec<u8>, NUSError> {
+    // Build the download URL. The structure is download/<TID>/<CID>
+    let endpoint_url = if wiiu_endpoint {
+        WII_U_NUS_ENDPOINT.to_owned()
+    } else {
+        WII_NUS_ENDPOINT.to_owned()
+    };
+    let content_url = format!("{}{}/{:08X}", endpoint_url, &hex::encode(title_id), content_id);
+    let client = reqwest::blocking::Client::new();
+    let response = client.get(content_url).header(reqwest::header::USER_AGENT, "wii libnup/1.0").send()?;
+    if !response.status().is_success() {
+        return Err(NUSError::NotFound);
+    }
+    Ok(response.bytes()?.to_vec())
+}
+
+/// Downloads all contents from the specified title from the NUS.
+pub fn download_contents(tmd: &tmd::TMD, wiiu_endpoint: bool) -> Result<Vec<Vec<u8>>, NUSError> {
+    let content_ids: Vec<u32> = tmd.content_records.iter().map(|record| { record.content_id }).collect();
+    let mut contents: Vec<Vec<u8>> = Vec::new();
+    for id in content_ids {
+        contents.push(download_content(tmd.title_id, id, wiiu_endpoint)?);
+    }
+    Ok(contents)
+}
+
+/// Downloads the Ticket for a specified Title ID from the NUS, if it's available.
+pub fn download_ticket(title_id: [u8; 8], wiiu_endpoint: bool) -> Result<Vec<u8>, NUSError> {
+    // Build the download URL. The structure is download/<TID>/cetk.
+    let endpoint_url = if wiiu_endpoint {
+        WII_U_NUS_ENDPOINT.to_owned()
+    } else {
+        WII_NUS_ENDPOINT.to_owned()
+    };
+    let tik_url = format!("{}{}/cetk", endpoint_url, &hex::encode(title_id));
+    let client = reqwest::blocking::Client::new();
+    let response = client.get(tik_url).header(reqwest::header::USER_AGENT, "wii libnup/1.0").send()?;
+    if !response.status().is_success() {
+        return Err(NUSError::NotFound);
+    }
+    let tik = ticket::Ticket::from_bytes(&response.bytes()?).map_err(|_| NUSError::InvalidData)?;
+    tik.to_bytes().map_err(|_| NUSError::InvalidData)
+}
+
+/// Downloads an entire title with all of its content from the NUS and returns a Title instance.
+pub fn download_title(title_id: [u8; 8], title_version: Option<u16>, wiiu_endpoint: bool) -> Result<title::Title, NUSError> {
+    // Download the individual components of a title and then build a title from them.
+    let cert_chain = cert::CertificateChain::from_bytes(&download_cert_chain(wiiu_endpoint)?)?;
+    let tmd = tmd::TMD::from_bytes(&download_tmd(title_id, title_version, wiiu_endpoint)?)?;
+    let tik = ticket::Ticket::from_bytes(&download_ticket(title_id, wiiu_endpoint)?)?;
+    let content_region = content::ContentRegion::from_contents(download_contents(&tmd, wiiu_endpoint)?, tmd.content_records.clone())?;
+    let title = title::Title::from_parts(cert_chain, None, tik, tmd, content_region, None)?;
+    Ok(title)
+}
+
+/// Downloads the TMD for a specified Title ID from the NUS.
+pub fn download_tmd(title_id: [u8; 8], title_version: Option<u16>, wiiu_endpoint: bool) -> Result<Vec<u8>, NUSError> {
+    // Build the download URL. The structure is download/<TID>/tmd for latest and 
+    // download/<TID>/tmd.<version> for when a specific version is requested.
+    let endpoint_url = if wiiu_endpoint {
+        WII_U_NUS_ENDPOINT.to_owned()
+    } else {
+        WII_NUS_ENDPOINT.to_owned()
+    };
+    let tmd_url = if title_version.is_some() {
+        format!("{}{}/tmd.{}", endpoint_url, &hex::encode(title_id), title_version.unwrap())
+    } else {
+        format!("{}{}/tmd", endpoint_url, &hex::encode(title_id))
+    };
+    let client = reqwest::blocking::Client::new();
+    let response = client.get(tmd_url).header(reqwest::header::USER_AGENT, "wii libnup/1.0").send()?;
+    if !response.status().is_success() {
+        return Err(NUSError::NotFound);
+    }
+    let tmd = tmd::TMD::from_bytes(&response.bytes()?).map_err(|_| NUSError::InvalidData)?;
+    tmd.to_bytes().map_err(|_| NUSError::InvalidData)
+}

src/title/tmd.rs

@@ -50,11 +50,11 @@ impl fmt::Display for TitleType {
 
 #[derive(Debug, Clone)]
 pub enum ContentType {
-    Normal,
-    Development,
-    HashTree,
-    DLC,
-    Shared,
+    Normal = 1,
+    Development = 2,
+    HashTree = 3,
+    DLC = 16385,
+    Shared = 32769,
 }
 
 impl fmt::Display for ContentType {
@@ -70,8 +70,8 @@ impl fmt::Display for ContentType {
 }
 
 pub enum AccessRight {
-    AHB,
-    DVDVideo,
+    AHB = 0,
+    DVDVideo = 1,
 }
 
 #[derive(Debug, Clone)]
@@ -332,10 +332,7 @@ impl TMD {
 
     /// Gets whether a specified access right is enabled in a TMD.
     pub fn check_access_right(&self, right: AccessRight) -> bool {
-        match right {
-            AccessRight::AHB => (self.access_rights & (1 << 0)) != 0,
-            AccessRight::DVDVideo => (self.access_rights & (1 << 1)) != 0,
-        }
+        self.access_rights & (1 << right as u8) != 0
     }
 
     /// Gets the name of the certificate used to sign a TMD as a string.