rtc_stun/
xoraddr.rs

1#[cfg(test)]
2mod xoraddr_test;
3
4use crate::addr::*;
5use crate::attributes::*;
6use crate::checks::*;
7use crate::message::*;
8use shared::error::*;
9
10use std::fmt;
11use std::mem;
12use std::net::{IpAddr, Ipv4Addr, Ipv6Addr};
13
14const WORD_SIZE: usize = mem::size_of::<usize>();
15
16//var supportsUnaligned = runtime.GOARCH == "386" || runtime.GOARCH == "amd64" // nolint:gochecknoglobals
17
18// fast_xor_bytes xors in bulk. It only works on architectures that
19// support unaligned read/writes.
20/*TODO: fn fast_xor_bytes(dst:&[u8], a:&[u8], b:&[u8]) ->usize {
21    let mut n = a.len();
22    if b.len() < n {
23        n = b.len();
24    }
25
26    let w = n / WORD_SIZE;
27    if w > 0 {
28        let dw = *(*[]uintptr)(unsafe.Pointer(&dst))
29        let aw = *(*[]uintptr)(unsafe.Pointer(&a))
30        let bw = *(*[]uintptr)(unsafe.Pointer(&b))
31        for i := 0; i < w; i++ {
32            dw[i] = aw[i] ^ bw[i]
33        }
34    }
35
36    for i := n - n%WORD_SIZE; i < n; i++ {
37        dst[i] = a[i] ^ b[i]
38    }
39
40    return n
41}*/
42
43fn safe_xor_bytes(dst: &mut [u8], a: &[u8], b: &[u8]) -> usize {
44    let mut n = a.len();
45    if b.len() < n {
46        n = b.len();
47    }
48    if dst.len() < n {
49        n = dst.len();
50    }
51    for i in 0..n {
52        dst[i] = a[i] ^ b[i];
53    }
54    n
55}
56
57/// xor_bytes xors the bytes in a and b. The destination is assumed to have enough
58/// space. Returns the number of bytes xor'd.
59pub fn xor_bytes(dst: &mut [u8], a: &[u8], b: &[u8]) -> usize {
60    //TODO: if supportsUnaligned {
61    //	return fastXORBytes(dst, a, b)
62    //}
63    safe_xor_bytes(dst, a, b)
64}
65
66/// XORMappedAddress implements XOR-MAPPED-ADDRESS attribute.
67///
68/// RFC 5389 Section 15.2
69pub struct XorMappedAddress {
70    pub ip: IpAddr,
71    pub port: u16,
72}
73
74impl Default for XorMappedAddress {
75    fn default() -> Self {
76        XorMappedAddress {
77            ip: IpAddr::V4(Ipv4Addr::from(0)),
78            port: 0,
79        }
80    }
81}
82
83impl fmt::Display for XorMappedAddress {
84    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
85        match self.ip {
86            IpAddr::V4(_) => write!(f, "{}:{}", self.ip, self.port),
87            IpAddr::V6(_) => write!(f, "[{}]:{}", self.ip, self.port),
88        }
89    }
90}
91
92impl Setter for XorMappedAddress {
93    /// add_to adds XOR-MAPPED-ADDRESS to m. Can return ErrBadIPLength
94    /// if len(a.IP) is invalid.
95    fn add_to(&self, m: &mut Message) -> Result<()> {
96        self.add_to_as(m, ATTR_XORMAPPED_ADDRESS)
97    }
98}
99
100impl Getter for XorMappedAddress {
101    /// get_from decodes XOR-MAPPED-ADDRESS attribute in message and returns
102    /// error if any. While decoding, a.IP is reused if possible and can be
103    /// rendered to invalid state (e.g. if a.IP was set to IPv6 and then
104    /// IPv4 value were decoded into it), be careful.
105    fn get_from(&mut self, m: &Message) -> Result<()> {
106        self.get_from_as(m, ATTR_XORMAPPED_ADDRESS)
107    }
108}
109
110impl XorMappedAddress {
111    /// add_to_as adds XOR-MAPPED-ADDRESS value to m as t attribute.
112    pub fn add_to_as(&self, m: &mut Message, t: AttrType) -> Result<()> {
113        let (family, ip_len, ip) = match self.ip {
114            IpAddr::V4(ipv4) => (FAMILY_IPV4, IPV4LEN, ipv4.octets().to_vec()),
115            IpAddr::V6(ipv6) => (FAMILY_IPV6, IPV6LEN, ipv6.octets().to_vec()),
116        };
117
118        let mut value = [0; 32 + 128];
119        //value[0] = 0 // first 8 bits are zeroes
120        let mut xor_value = vec![0; IPV6LEN];
121        xor_value[4..].copy_from_slice(&m.transaction_id.0);
122        xor_value[0..4].copy_from_slice(&MAGIC_COOKIE.to_be_bytes());
123        value[0..2].copy_from_slice(&family.to_be_bytes());
124        value[2..4].copy_from_slice(&(self.port ^ (MAGIC_COOKIE >> 16) as u16).to_be_bytes());
125        xor_bytes(&mut value[4..4 + ip_len], &ip, &xor_value);
126        m.add(t, &value[..4 + ip_len]);
127        Ok(())
128    }
129
130    /// get_from_as decodes XOR-MAPPED-ADDRESS attribute value in message
131    /// getting it as for t type.
132    pub fn get_from_as(&mut self, m: &Message, t: AttrType) -> Result<()> {
133        let v = m.get(t)?;
134        if v.len() <= 4 {
135            return Err(Error::ErrUnexpectedEof);
136        }
137
138        let family = u16::from_be_bytes([v[0], v[1]]);
139        if family != FAMILY_IPV6 && family != FAMILY_IPV4 {
140            return Err(Error::Other(format!("bad value {family}")));
141        }
142
143        check_overflow(
144            t,
145            v[4..].len(),
146            if family == FAMILY_IPV4 {
147                IPV4LEN
148            } else {
149                IPV6LEN
150            },
151        )?;
152        self.port = u16::from_be_bytes([v[2], v[3]]) ^ (MAGIC_COOKIE >> 16) as u16;
153        let mut xor_value = vec![0; 4 + TRANSACTION_ID_SIZE];
154        xor_value[0..4].copy_from_slice(&MAGIC_COOKIE.to_be_bytes());
155        xor_value[4..].copy_from_slice(&m.transaction_id.0);
156
157        if family == FAMILY_IPV6 {
158            let mut ip = [0; IPV6LEN];
159            xor_bytes(&mut ip, &v[4..], &xor_value);
160            self.ip = IpAddr::V6(Ipv6Addr::from(ip));
161        } else {
162            let mut ip = [0; IPV4LEN];
163            xor_bytes(&mut ip, &v[4..], &xor_value);
164            self.ip = IpAddr::V4(Ipv4Addr::from(ip));
165        };
166
167        Ok(())
168    }
169}
rtc_stun/xoraddr.rs

rtc_stun/
xoraddr.rs
