1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
|
//! Query network interface addresses
//!
//! Uses the Linux and/or BSD specific function `getifaddrs` to query the list
//! of interfaces and their associated addresses.
use cfg_if::cfg_if;
#[cfg(any(target_os = "ios", target_os = "macos"))]
use std::convert::TryFrom;
use std::ffi;
use std::iter::Iterator;
use std::mem;
use std::option::Option;
use crate::net::if_::*;
use crate::sys::socket::{SockaddrLike, SockaddrStorage};
use crate::{Errno, Result};
/// Describes a single address for an interface as returned by `getifaddrs`.
#[derive(Clone, Debug, Eq, Hash, PartialEq)]
pub struct InterfaceAddress {
/// Name of the network interface
pub interface_name: String,
/// Flags as from `SIOCGIFFLAGS` ioctl
pub flags: InterfaceFlags,
/// Network address of this interface
pub address: Option<SockaddrStorage>,
/// Netmask of this interface
pub netmask: Option<SockaddrStorage>,
/// Broadcast address of this interface, if applicable
pub broadcast: Option<SockaddrStorage>,
/// Point-to-point destination address
pub destination: Option<SockaddrStorage>,
}
cfg_if! {
if #[cfg(any(target_os = "android", target_os = "emscripten", target_os = "fuchsia", target_os = "linux"))] {
fn get_ifu_from_sockaddr(info: &libc::ifaddrs) -> *const libc::sockaddr {
info.ifa_ifu
}
} else {
fn get_ifu_from_sockaddr(info: &libc::ifaddrs) -> *const libc::sockaddr {
info.ifa_dstaddr
}
}
}
/// Workaround a bug in XNU where netmasks will always have the wrong size in
/// the sa_len field due to the kernel ignoring trailing zeroes in the structure
/// when setting the field. See https://github.com/nix-rust/nix/issues/1709#issuecomment-1199304470
///
/// To fix this, we stack-allocate a new sockaddr_storage, zero it out, and
/// memcpy sa_len of the netmask to that new storage. Finally, we reset the
/// ss_len field to sizeof(sockaddr_storage). This is supposedly valid as all
/// members of the sockaddr_storage are "ok" with being zeroed out (there are
/// no pointers).
#[cfg(any(target_os = "ios", target_os = "macos"))]
unsafe fn workaround_xnu_bug(info: &libc::ifaddrs) -> Option<SockaddrStorage> {
let src_sock = info.ifa_netmask;
if src_sock.is_null() {
return None;
}
let mut dst_sock = mem::MaybeUninit::<libc::sockaddr_storage>::zeroed();
// memcpy only sa_len bytes, assume the rest is zero
std::ptr::copy_nonoverlapping(
src_sock as *const u8,
dst_sock.as_mut_ptr() as *mut u8,
(*src_sock).sa_len.into(),
);
// Initialize ss_len to sizeof(libc::sockaddr_storage).
(*dst_sock.as_mut_ptr()).ss_len =
u8::try_from(mem::size_of::<libc::sockaddr_storage>()).unwrap();
let dst_sock = dst_sock.assume_init();
let dst_sock_ptr =
&dst_sock as *const libc::sockaddr_storage as *const libc::sockaddr;
SockaddrStorage::from_raw(dst_sock_ptr, None)
}
impl InterfaceAddress {
/// Create an `InterfaceAddress` from the libc struct.
fn from_libc_ifaddrs(info: &libc::ifaddrs) -> InterfaceAddress {
let ifname = unsafe { ffi::CStr::from_ptr(info.ifa_name) };
let address = unsafe { SockaddrStorage::from_raw(info.ifa_addr, None) };
#[cfg(any(target_os = "ios", target_os = "macos"))]
let netmask = unsafe { workaround_xnu_bug(info) };
#[cfg(not(any(target_os = "ios", target_os = "macos")))]
let netmask =
unsafe { SockaddrStorage::from_raw(info.ifa_netmask, None) };
let mut addr = InterfaceAddress {
interface_name: ifname.to_string_lossy().to_string(),
flags: InterfaceFlags::from_bits_truncate(info.ifa_flags as i32),
address,
netmask,
broadcast: None,
destination: None,
};
let ifu = get_ifu_from_sockaddr(info);
if addr.flags.contains(InterfaceFlags::IFF_POINTOPOINT) {
addr.destination = unsafe { SockaddrStorage::from_raw(ifu, None) };
} else if addr.flags.contains(InterfaceFlags::IFF_BROADCAST) {
addr.broadcast = unsafe { SockaddrStorage::from_raw(ifu, None) };
}
addr
}
}
/// Holds the results of `getifaddrs`.
///
/// Use the function `getifaddrs` to create this Iterator. Note that the
/// actual list of interfaces can be iterated once and will be freed as
/// soon as the Iterator goes out of scope.
#[derive(Debug, Eq, Hash, PartialEq)]
pub struct InterfaceAddressIterator {
base: *mut libc::ifaddrs,
next: *mut libc::ifaddrs,
}
impl Drop for InterfaceAddressIterator {
fn drop(&mut self) {
unsafe { libc::freeifaddrs(self.base) };
}
}
impl Iterator for InterfaceAddressIterator {
type Item = InterfaceAddress;
fn next(&mut self) -> Option<<Self as Iterator>::Item> {
match unsafe { self.next.as_ref() } {
Some(ifaddr) => {
self.next = ifaddr.ifa_next;
Some(InterfaceAddress::from_libc_ifaddrs(ifaddr))
}
None => None,
}
}
}
/// Get interface addresses using libc's `getifaddrs`
///
/// Note that the underlying implementation differs between OSes. Only the
/// most common address families are supported by the nix crate (due to
/// lack of time and complexity of testing). The address family is encoded
/// in the specific variant of `SockaddrStorage` returned for the fields
/// `address`, `netmask`, `broadcast`, and `destination`. For any entry not
/// supported, the returned list will contain a `None` entry.
///
/// # Example
/// ```
/// let addrs = nix::ifaddrs::getifaddrs().unwrap();
/// for ifaddr in addrs {
/// match ifaddr.address {
/// Some(address) => {
/// println!("interface {} address {}",
/// ifaddr.interface_name, address);
/// },
/// None => {
/// println!("interface {} with unsupported address family",
/// ifaddr.interface_name);
/// }
/// }
/// }
/// ```
pub fn getifaddrs() -> Result<InterfaceAddressIterator> {
let mut addrs = mem::MaybeUninit::<*mut libc::ifaddrs>::uninit();
unsafe {
Errno::result(libc::getifaddrs(addrs.as_mut_ptr())).map(|_| {
InterfaceAddressIterator {
base: addrs.assume_init(),
next: addrs.assume_init(),
}
})
}
}
#[cfg(test)]
mod tests {
use super::*;
// Only checks if `getifaddrs` can be invoked without panicking.
#[test]
fn test_getifaddrs() {
let _ = getifaddrs();
}
// Ensures getting the netmask works, and in particular that
// `workaround_xnu_bug` works properly.
#[test]
fn test_getifaddrs_netmask_correct() {
let addrs = getifaddrs().unwrap();
for iface in addrs {
let sock = if let Some(sock) = iface.netmask {
sock
} else {
continue;
};
if sock.family() == Some(crate::sys::socket::AddressFamily::Inet) {
let _ = sock.as_sockaddr_in().unwrap();
return;
} else if sock.family()
== Some(crate::sys::socket::AddressFamily::Inet6)
{
let _ = sock.as_sockaddr_in6().unwrap();
return;
}
}
panic!("No address?");
}
}
|
