1//! A private parser implementation of IPv4, IPv6, and socket addresses.
2//!
3//! This module is "publicly exported" through the `FromStr` implementations
4//! below.
5
6use crate::error::Error;
7use crate::fmt;
8use crate::net::{IpAddr, Ipv4Addr, Ipv6Addr, SocketAddr, SocketAddrV4, SocketAddrV6};
9use crate::str::FromStr;
10
11trait ReadNumberHelper: Sized {
12 const ZERO: Self;
13 fn checked_mul(&self, other: u32) -> Option<Self>;
14 fn checked_add(&self, other: u32) -> Option<Self>;
15}
16
17macro_rules! impl_helper {
18 ($($t:ty)*) => ($(impl ReadNumberHelper for $t {
19 const ZERO: Self = 0;
20 #[inline]
21 fn checked_mul(&self, other: u32) -> Option<Self> {
22 Self::checked_mul(*self, other.try_into().ok()?)
23 }
24 #[inline]
25 fn checked_add(&self, other: u32) -> Option<Self> {
26 Self::checked_add(*self, other.try_into().ok()?)
27 }
28 })*)
29}
30
31impl_helper! { u8 u16 u32 }
32
33struct Parser<'a> {
34 // Parsing as ASCII, so can use byte array.
35 state: &'a [u8],
36}
37
38impl<'a> Parser<'a> {
39 fn new(input: &'a [u8]) -> Parser<'a> {
40 Parser { state: input }
41 }
42
43 /// Run a parser, and restore the pre-parse state if it fails.
44 fn read_atomically<T, F>(&mut self, inner: F) -> Option<T>
45 where
46 F: FnOnce(&mut Parser<'_>) -> Option<T>,
47 {
48 let state = self.state;
49 let result = inner(self);
50 if result.is_none() {
51 self.state = state;
52 }
53 result
54 }
55
56 /// Run a parser, but fail if the entire input wasn't consumed.
57 /// Doesn't run atomically.
58 fn parse_with<T, F>(&mut self, inner: F, kind: AddrKind) -> Result<T, AddrParseError>
59 where
60 F: FnOnce(&mut Parser<'_>) -> Option<T>,
61 {
62 let result = inner(self);
63 if self.state.is_empty() { result } else { None }.ok_or(AddrParseError(kind))
64 }
65
66 /// Peek the next character from the input
67 fn peek_char(&self) -> Option<char> {
68 self.state.first().map(|&b| char::from(b))
69 }
70
71 /// Reads the next character from the input
72 fn read_char(&mut self) -> Option<char> {
73 self.state.split_first().map(|(&b, tail)| {
74 self.state = tail;
75 char::from(b)
76 })
77 }
78
79 #[must_use]
80 /// Reads the next character from the input if it matches the target.
81 fn read_given_char(&mut self, target: char) -> Option<()> {
82 self.read_atomically(|p| {
83 p.read_char().and_then(|c| if c == target { Some(()) } else { None })
84 })
85 }
86
87 /// Helper for reading separators in an indexed loop. Reads the separator
88 /// character iff index > 0, then runs the parser. When used in a loop,
89 /// the separator character will only be read on index > 0 (see
90 /// read_ipv4_addr for an example)
91 fn read_separator<T, F>(&mut self, sep: char, index: usize, inner: F) -> Option<T>
92 where
93 F: FnOnce(&mut Parser<'_>) -> Option<T>,
94 {
95 self.read_atomically(move |p| {
96 if index > 0 {
97 p.read_given_char(sep)?;
98 }
99 inner(p)
100 })
101 }
102
103 // Read a number off the front of the input in the given radix, stopping
104 // at the first non-digit character or eof. Fails if the number has more
105 // digits than max_digits or if there is no number.
106 //
107 // INVARIANT: `max_digits` must be less than the number of digits that `u32`
108 // can represent.
109 fn read_number<T: ReadNumberHelper + TryFrom<u32>>(
110 &mut self,
111 radix: u32,
112 max_digits: Option<usize>,
113 allow_zero_prefix: bool,
114 ) -> Option<T> {
115 self.read_atomically(move |p| {
116 let mut digit_count = 0;
117 let has_leading_zero = p.peek_char() == Some('0');
118
119 // If max_digits.is_some(), then we are parsing a `u8` or `u16` and
120 // don't need to use checked arithmetic since it fits within a `u32`.
121 let result = if let Some(max_digits) = max_digits {
122 // u32::MAX = 4_294_967_295u32, which is 10 digits long.
123 // `max_digits` must be less than 10 to not overflow a `u32`.
124 debug_assert!(max_digits < 10);
125
126 let mut result = 0_u32;
127 while let Some(digit) = p.read_atomically(|p| p.read_char()?.to_digit(radix)) {
128 result *= radix;
129 result += digit;
130 digit_count += 1;
131
132 if digit_count > max_digits {
133 return None;
134 }
135 }
136
137 result.try_into().ok()
138 } else {
139 let mut result = T::ZERO;
140
141 while let Some(digit) = p.read_atomically(|p| p.read_char()?.to_digit(radix)) {
142 result = result.checked_mul(radix)?;
143 result = result.checked_add(digit)?;
144 digit_count += 1;
145 }
146
147 Some(result)
148 };
149
150 if digit_count == 0 {
151 None
152 } else if !allow_zero_prefix && has_leading_zero && digit_count > 1 {
153 None
154 } else {
155 result
156 }
157 })
158 }
159
160 /// Reads an IPv4 address.
161 fn read_ipv4_addr(&mut self) -> Option<Ipv4Addr> {
162 self.read_atomically(|p| {
163 let mut groups = [0; 4];
164
165 for (i, slot) in groups.iter_mut().enumerate() {
166 *slot = p.read_separator('.', i, |p| {
167 // Disallow octal number in IP string.
168 // https://tools.ietf.org/html/rfc6943#section-3.1.1
169 p.read_number(10, Some(3), false)
170 })?;
171 }
172
173 Some(groups.into())
174 })
175 }
176
177 /// Reads an IPv6 address.
178 fn read_ipv6_addr(&mut self) -> Option<Ipv6Addr> {
179 /// Read a chunk of an IPv6 address into `groups`. Returns the number
180 /// of groups read, along with a bool indicating if an embedded
181 /// trailing IPv4 address was read. Specifically, read a series of
182 /// colon-separated IPv6 groups (0x0000 - 0xFFFF), with an optional
183 /// trailing embedded IPv4 address.
184 fn read_groups(p: &mut Parser<'_>, groups: &mut [u16]) -> (usize, bool) {
185 let limit = groups.len();
186
187 for (i, slot) in groups.iter_mut().enumerate() {
188 // Try to read a trailing embedded IPv4 address. There must be
189 // at least two groups left.
190 if i < limit - 1 {
191 let ipv4 = p.read_separator(':', i, |p| p.read_ipv4_addr());
192
193 if let Some(v4_addr) = ipv4 {
194 let [one, two, three, four] = v4_addr.octets();
195 groups[i + 0] = u16::from_be_bytes([one, two]);
196 groups[i + 1] = u16::from_be_bytes([three, four]);
197 return (i + 2, true);
198 }
199 }
200
201 let group = p.read_separator(':', i, |p| p.read_number(16, Some(4), true));
202
203 match group {
204 Some(g) => *slot = g,
205 None => return (i, false),
206 }
207 }
208 (groups.len(), false)
209 }
210
211 self.read_atomically(|p| {
212 // Read the front part of the address; either the whole thing, or up
213 // to the first ::
214 let mut head = [0; 8];
215 let (head_size, head_ipv4) = read_groups(p, &mut head);
216
217 if head_size == 8 {
218 return Some(head.into());
219 }
220
221 // IPv4 part is not allowed before `::`
222 if head_ipv4 {
223 return None;
224 }
225
226 // Read `::` if previous code parsed less than 8 groups.
227 // `::` indicates one or more groups of 16 bits of zeros.
228 p.read_given_char(':')?;
229 p.read_given_char(':')?;
230
231 // Read the back part of the address. The :: must contain at least one
232 // set of zeroes, so our max length is 7.
233 let mut tail = [0; 7];
234 let limit = 8 - (head_size + 1);
235 let (tail_size, _) = read_groups(p, &mut tail[..limit]);
236
237 // Concat the head and tail of the IP address
238 head[(8 - tail_size)..8].copy_from_slice(&tail[..tail_size]);
239
240 Some(head.into())
241 })
242 }
243
244 /// Reads an IP address, either IPv4 or IPv6.
245 fn read_ip_addr(&mut self) -> Option<IpAddr> {
246 self.read_ipv4_addr().map(IpAddr::V4).or_else(move || self.read_ipv6_addr().map(IpAddr::V6))
247 }
248
249 /// Reads a `:` followed by a port in base 10.
250 fn read_port(&mut self) -> Option<u16> {
251 self.read_atomically(|p| {
252 p.read_given_char(':')?;
253 p.read_number(10, None, true)
254 })
255 }
256
257 /// Reads a `%` followed by a scope ID in base 10.
258 fn read_scope_id(&mut self) -> Option<u32> {
259 self.read_atomically(|p| {
260 p.read_given_char('%')?;
261 p.read_number(10, None, true)
262 })
263 }
264
265 /// Reads an IPv4 address with a port.
266 fn read_socket_addr_v4(&mut self) -> Option<SocketAddrV4> {
267 self.read_atomically(|p| {
268 let ip = p.read_ipv4_addr()?;
269 let port = p.read_port()?;
270 Some(SocketAddrV4::new(ip, port))
271 })
272 }
273
274 /// Reads an IPv6 address with a port.
275 fn read_socket_addr_v6(&mut self) -> Option<SocketAddrV6> {
276 self.read_atomically(|p| {
277 p.read_given_char('[')?;
278 let ip = p.read_ipv6_addr()?;
279 let scope_id = p.read_scope_id().unwrap_or(0);
280 p.read_given_char(']')?;
281
282 let port = p.read_port()?;
283 Some(SocketAddrV6::new(ip, port, 0, scope_id))
284 })
285 }
286
287 /// Reads an IP address with a port.
288 fn read_socket_addr(&mut self) -> Option<SocketAddr> {
289 self.read_socket_addr_v4()
290 .map(SocketAddr::V4)
291 .or_else(|| self.read_socket_addr_v6().map(SocketAddr::V6))
292 }
293}
294
295impl IpAddr {
296 /// Parse an IP address from a slice of bytes.
297 ///
298 /// ```
299 /// #![feature(addr_parse_ascii)]
300 ///
301 /// use std::net::{IpAddr, Ipv4Addr, Ipv6Addr};
302 ///
303 /// let localhost_v4 = IpAddr::V4(Ipv4Addr::new(127, 0, 0, 1));
304 /// let localhost_v6 = IpAddr::V6(Ipv6Addr::new(0, 0, 0, 0, 0, 0, 0, 1));
305 ///
306 /// assert_eq!(IpAddr::parse_ascii(b"127.0.0.1"), Ok(localhost_v4));
307 /// assert_eq!(IpAddr::parse_ascii(b"::1"), Ok(localhost_v6));
308 /// ```
309 #[unstable(feature = "addr_parse_ascii", issue = "101035")]
310 pub fn parse_ascii(b: &[u8]) -> Result<Self, AddrParseError> {
311 Parser::new(b).parse_with(|p| p.read_ip_addr(), kind:AddrKind::Ip)
312 }
313}
314
315#[stable(feature = "ip_addr", since = "1.7.0")]
316impl FromStr for IpAddr {
317 type Err = AddrParseError;
318 fn from_str(s: &str) -> Result<IpAddr, AddrParseError> {
319 Self::parse_ascii(s.as_bytes())
320 }
321}
322
323impl Ipv4Addr {
324 /// Parse an IPv4 address from a slice of bytes.
325 ///
326 /// ```
327 /// #![feature(addr_parse_ascii)]
328 ///
329 /// use std::net::Ipv4Addr;
330 ///
331 /// let localhost = Ipv4Addr::new(127, 0, 0, 1);
332 ///
333 /// assert_eq!(Ipv4Addr::parse_ascii(b"127.0.0.1"), Ok(localhost));
334 /// ```
335 #[unstable(feature = "addr_parse_ascii", issue = "101035")]
336 pub fn parse_ascii(b: &[u8]) -> Result<Self, AddrParseError> {
337 // don't try to parse if too long
338 if b.len() > 15 {
339 Err(AddrParseError(AddrKind::Ipv4))
340 } else {
341 Parser::new(b).parse_with(|p| p.read_ipv4_addr(), kind:AddrKind::Ipv4)
342 }
343 }
344}
345
346#[stable(feature = "rust1", since = "1.0.0")]
347impl FromStr for Ipv4Addr {
348 type Err = AddrParseError;
349 fn from_str(s: &str) -> Result<Ipv4Addr, AddrParseError> {
350 Self::parse_ascii(s.as_bytes())
351 }
352}
353
354impl Ipv6Addr {
355 /// Parse an IPv6 address from a slice of bytes.
356 ///
357 /// ```
358 /// #![feature(addr_parse_ascii)]
359 ///
360 /// use std::net::Ipv6Addr;
361 ///
362 /// let localhost = Ipv6Addr::new(0, 0, 0, 0, 0, 0, 0, 1);
363 ///
364 /// assert_eq!(Ipv6Addr::parse_ascii(b"::1"), Ok(localhost));
365 /// ```
366 #[unstable(feature = "addr_parse_ascii", issue = "101035")]
367 pub fn parse_ascii(b: &[u8]) -> Result<Self, AddrParseError> {
368 Parser::new(b).parse_with(|p| p.read_ipv6_addr(), kind:AddrKind::Ipv6)
369 }
370}
371
372#[stable(feature = "rust1", since = "1.0.0")]
373impl FromStr for Ipv6Addr {
374 type Err = AddrParseError;
375 fn from_str(s: &str) -> Result<Ipv6Addr, AddrParseError> {
376 Self::parse_ascii(s.as_bytes())
377 }
378}
379
380impl SocketAddrV4 {
381 /// Parse an IPv4 socket address from a slice of bytes.
382 ///
383 /// ```
384 /// #![feature(addr_parse_ascii)]
385 ///
386 /// use std::net::{Ipv4Addr, SocketAddrV4};
387 ///
388 /// let socket = SocketAddrV4::new(Ipv4Addr::new(127, 0, 0, 1), 8080);
389 ///
390 /// assert_eq!(SocketAddrV4::parse_ascii(b"127.0.0.1:8080"), Ok(socket));
391 /// ```
392 #[unstable(feature = "addr_parse_ascii", issue = "101035")]
393 pub fn parse_ascii(b: &[u8]) -> Result<Self, AddrParseError> {
394 Parser::new(b).parse_with(|p| p.read_socket_addr_v4(), kind:AddrKind::SocketV4)
395 }
396}
397
398#[stable(feature = "socket_addr_from_str", since = "1.5.0")]
399impl FromStr for SocketAddrV4 {
400 type Err = AddrParseError;
401 fn from_str(s: &str) -> Result<SocketAddrV4, AddrParseError> {
402 Self::parse_ascii(s.as_bytes())
403 }
404}
405
406impl SocketAddrV6 {
407 /// Parse an IPv6 socket address from a slice of bytes.
408 ///
409 /// ```
410 /// #![feature(addr_parse_ascii)]
411 ///
412 /// use std::net::{Ipv6Addr, SocketAddrV6};
413 ///
414 /// let socket = SocketAddrV6::new(Ipv6Addr::new(0x2001, 0xdb8, 0, 0, 0, 0, 0, 1), 8080, 0, 0);
415 ///
416 /// assert_eq!(SocketAddrV6::parse_ascii(b"[2001:db8::1]:8080"), Ok(socket));
417 /// ```
418 #[unstable(feature = "addr_parse_ascii", issue = "101035")]
419 pub fn parse_ascii(b: &[u8]) -> Result<Self, AddrParseError> {
420 Parser::new(b).parse_with(|p| p.read_socket_addr_v6(), kind:AddrKind::SocketV6)
421 }
422}
423
424#[stable(feature = "socket_addr_from_str", since = "1.5.0")]
425impl FromStr for SocketAddrV6 {
426 type Err = AddrParseError;
427 fn from_str(s: &str) -> Result<SocketAddrV6, AddrParseError> {
428 Self::parse_ascii(s.as_bytes())
429 }
430}
431
432impl SocketAddr {
433 /// Parse a socket address from a slice of bytes.
434 ///
435 /// ```
436 /// #![feature(addr_parse_ascii)]
437 ///
438 /// use std::net::{IpAddr, Ipv4Addr, Ipv6Addr, SocketAddr};
439 ///
440 /// let socket_v4 = SocketAddr::new(IpAddr::V4(Ipv4Addr::new(127, 0, 0, 1)), 8080);
441 /// let socket_v6 = SocketAddr::new(IpAddr::V6(Ipv6Addr::new(0, 0, 0, 0, 0, 0, 0, 1)), 8080);
442 ///
443 /// assert_eq!(SocketAddr::parse_ascii(b"127.0.0.1:8080"), Ok(socket_v4));
444 /// assert_eq!(SocketAddr::parse_ascii(b"[::1]:8080"), Ok(socket_v6));
445 /// ```
446 #[unstable(feature = "addr_parse_ascii", issue = "101035")]
447 pub fn parse_ascii(b: &[u8]) -> Result<Self, AddrParseError> {
448 Parser::new(b).parse_with(|p| p.read_socket_addr(), kind:AddrKind::Socket)
449 }
450}
451
452#[stable(feature = "rust1", since = "1.0.0")]
453impl FromStr for SocketAddr {
454 type Err = AddrParseError;
455 fn from_str(s: &str) -> Result<SocketAddr, AddrParseError> {
456 Self::parse_ascii(s.as_bytes())
457 }
458}
459
460#[derive(Debug, Clone, PartialEq, Eq)]
461enum AddrKind {
462 Ip,
463 Ipv4,
464 Ipv6,
465 Socket,
466 SocketV4,
467 SocketV6,
468}
469
470/// An error which can be returned when parsing an IP address or a socket address.
471///
472/// This error is used as the error type for the [`FromStr`] implementation for
473/// [`IpAddr`], [`Ipv4Addr`], [`Ipv6Addr`], [`SocketAddr`], [`SocketAddrV4`], and
474/// [`SocketAddrV6`].
475///
476/// # Potential causes
477///
478/// `AddrParseError` may be thrown because the provided string does not parse as the given type,
479/// often because it includes information only handled by a different address type.
480///
481/// ```should_panic
482/// use std::net::IpAddr;
483/// let _foo: IpAddr = "127.0.0.1:8080".parse().expect("Cannot handle the socket port");
484/// ```
485///
486/// [`IpAddr`] doesn't handle the port. Use [`SocketAddr`] instead.
487///
488/// ```
489/// use std::net::SocketAddr;
490///
491/// // No problem, the `panic!` message has disappeared.
492/// let _foo: SocketAddr = "127.0.0.1:8080".parse().expect("unreachable panic");
493/// ```
494#[stable(feature = "rust1", since = "1.0.0")]
495#[derive(Debug, Clone, PartialEq, Eq)]
496pub struct AddrParseError(AddrKind);
497
498#[stable(feature = "addr_parse_error_error", since = "1.4.0")]
499impl fmt::Display for AddrParseError {
500 #[allow(deprecated, deprecated_in_future)]
501 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
502 fmt.write_str(self.description())
503 }
504}
505
506#[stable(feature = "addr_parse_error_error", since = "1.4.0")]
507impl Error for AddrParseError {
508 #[allow(deprecated)]
509 fn description(&self) -> &str {
510 match self.0 {
511 AddrKind::Ip => "invalid IP address syntax",
512 AddrKind::Ipv4 => "invalid IPv4 address syntax",
513 AddrKind::Ipv6 => "invalid IPv6 address syntax",
514 AddrKind::Socket => "invalid socket address syntax",
515 AddrKind::SocketV4 => "invalid IPv4 socket address syntax",
516 AddrKind::SocketV6 => "invalid IPv6 socket address syntax",
517 }
518 }
519}
520