Skip to content

fix(bsd): size In6Ifreq to the real struct in6_ifreq and read ifru_flags6 #193

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Draft
andrewgazelka wants to merge 1 commit into
base: main
Choose a base branch
from
Draft

fix(bsd): size In6Ifreq to the real struct in6_ifreq and read ifru_flags6 #193

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
26 changes: 20 additions & 6 deletions src/os/bsd/ipv6_addr_flags.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -10,11 +10,24 @@ const IN6_IFF_DEPRECATED: u32 = 0x10;
const IN6_IFF_TEMPORARY: u32 = 0x80;

// `libc` does not expose `in6_ifreq` on FreeBSD/OpenBSD/NetBSD.
//
// Mirrors `struct in6_ifreq` from <netinet6/in6_var.h>. `SIOCGIFAFLAG_IN6` encodes
// `sizeof(struct in6_ifreq)` (0x120 = 288 bytes on LP64), and the kernel copies that many
// bytes in and out, so the union must be padded to the size of its largest member
// (`icmp6_ifstat`, 34 x u64 = 272 bytes). The flags are returned in `ifru_flags6`, which
// overlaps `ifru_addr` at the start of the union.
#[repr(C)]
struct In6Ifreq {
ifr_name: [u8; libc::IFNAMSIZ],
ifr_addr: libc::sockaddr_in6,
ifr_flags: libc::c_int,
ifr_ifru: In6IfreqUnion,
}

#[repr(C)]
union In6IfreqUnion {
ifru_addr: libc::sockaddr_in6,
ifru_flags6: libc::c_int,
// 8-byte aligned, like the u64 counters in `in6_ifstat` / `icmp6_ifstat`.
_size: [u64; 34],
}

pub(crate) fn get_ipv6_addr_flags(ifname: &str, addr: &Ipv6Addr) -> Ipv6AddrFlags {
Expand All @@ -25,6 +38,7 @@ pub(crate) fn get_ipv6_addr_flags(ifname: &str, addr: &Ipv6Addr) -> Ipv6AddrFlag
}

let mut req: In6Ifreq = std::mem::zeroed();
const _: () = assert!(std::mem::size_of::<In6Ifreq>() == 0x120);

let name_bytes = ifname.as_bytes();
let copy_len = name_bytes.len().min(libc::IFNAMSIZ - 1);
Expand All @@ -34,9 +48,9 @@ pub(crate) fn get_ipv6_addr_flags(ifname: &str, addr: &Ipv6Addr) -> Ipv6AddrFlag
copy_len,
);

req.ifr_addr.sin6_family = libc::AF_INET6 as libc::sa_family_t;
req.ifr_addr.sin6_len = std::mem::size_of::<libc::sockaddr_in6>() as u8;
req.ifr_addr.sin6_addr.s6_addr = addr.octets();
req.ifr_ifru.ifru_addr.sin6_family = libc::AF_INET6 as libc::sa_family_t;
req.ifr_ifru.ifru_addr.sin6_len = std::mem::size_of::<libc::sockaddr_in6>() as u8;
req.ifr_ifru.ifru_addr.sin6_addr.s6_addr = addr.octets();

let ret = libc::ioctl(fd, SIOCGIFAFLAG_IN6, &mut req);
libc::close(fd);
Expand All @@ -45,7 +59,7 @@ pub(crate) fn get_ipv6_addr_flags(ifname: &str, addr: &Ipv6Addr) -> Ipv6AddrFlag
return Ipv6AddrFlags::default();
}

let raw = req.ifr_flags as u32;
let raw = req.ifr_ifru.ifru_flags6 as u32;

Ipv6AddrFlags {
deprecated: raw & IN6_IFF_DEPRECATED != 0,
Expand Down