86 lines
2.3 KiB
Rust
86 lines
2.3 KiB
Rust
use crate::errors::*;
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use crate::ser::text::{quoted, DnsTextContext};
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use super::{DnsLabelRef, DnsName};
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/// Parse text representation of a domain name
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pub fn parse_name(context: &DnsTextContext, value: &str) -> Result<DnsName> {
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let raw = value.as_bytes();
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let mut name = DnsName::new_root();
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if raw == b"." {
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return Ok(name);
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} else if raw == b"@" {
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match context.origin() {
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Some(o) => return Ok(o.clone()),
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None => failure::bail!("@ invalid without $ORIGIN"),
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}
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}
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failure::ensure!(!raw.is_empty(), "invalid empty name");
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let mut label = Vec::new();
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let mut pos = 0;
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while pos < raw.len() {
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if raw[pos] == b'.' {
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failure::ensure!(!label.is_empty(), "empty label in name: {:?}", value);
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name.push_back(DnsLabelRef::new(&label)?)?;
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label.clear();
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} else if raw[pos] == b'\\' {
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failure::ensure!(
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pos + 1 < raw.len(),
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"unexpected end of name after backslash: {:?}",
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value
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);
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if raw[pos + 1] >= b'0' && raw[pos + 1] <= b'9' {
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// \ddd escape
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failure::ensure!(
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pos + 3 < raw.len(),
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"unexpected end of name after backslash with digit: {:?}",
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value
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);
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failure::ensure!(
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raw[pos + 2] >= b'0'
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&& raw[pos + 2] <= b'9' && raw[pos + 3] >= b'0'
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&& raw[pos + 3] <= b'9',
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"expected three digits after backslash in name: {:?}",
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name
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);
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let d1 = (raw[pos + 1] - b'0') as u32;
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let d2 = (raw[pos + 2] - b'0') as u32;
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let d3 = (raw[pos + 3] - b'0') as u32;
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let v = d1 * 100 + d2 * 10 + d3;
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failure::ensure!(v < 256, "invalid escape in name, {} > 255: {:?}", v, name);
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label.push(v as u8);
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} else {
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failure::ensure!(!quoted::is_ascii_whitespace(raw[pos+1]), "whitespace cannot be escaped with backslash prefix; encode it as \\{:03} in: {:?}", raw[pos+1], name);
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label.push(raw[pos + 1]);
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}
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} else {
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failure::ensure!(
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!quoted::is_ascii_whitespace(raw[pos]),
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"whitespace must be encoded as \\{:03} in: {:?}",
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raw[pos],
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name
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);
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label.push(raw[pos]);
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}
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pos += 1;
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}
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if !label.is_empty() {
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// no trailing dot, relative name
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// push last label
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name.push_back(DnsLabelRef::new(&label)?)?;
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match context.origin() {
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Some(o) => {
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for l in o {
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name.push_back(l)?;
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}
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},
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None => failure::bail!("missing trailing dot without $ORIGIN"),
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}
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}
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Ok(name)
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}
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