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Additions from the managarm port #1

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Merged
merged 4 commits into from
Mar 12, 2023
Merged

Additions from the managarm port #1

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f1a17f3
dhcpd: use constants for DHCP port numbers
no92 Mar 7, 2023
24084e6
dhcpd: don't connect to broadcast address, send_to instead
no92 Mar 7, 2023
a2aa417
dhcpd: fix compile warning on stable rust
no92 Mar 7, 2023
3faa3eb
dhcpd: allow specifying the interface name as a command-line arg
no92 Mar 7, 2023
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36 changes: 29 additions & 7 deletions src/main.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,9 @@ use simple_endian::BigEndian;
/// [RFC 8200 § 2]: https://www.rfc-editor.org/rfc/rfc791#section-3.2
pub const ADDR_SIZE: usize = 4;

pub const DHCP_SERVER_PORT: u16 = 67;
pub const DHCP_CLIENT_PORT: u16 = 68;

#[derive(Debug, Hash, PartialEq, Eq, PartialOrd, Ord, Clone, Copy, Default)]
pub struct Ipv4Addr(pub [u8; ADDR_SIZE]);

Expand Down Expand Up @@ -59,7 +62,6 @@ enum HType {
Ethernet = 1u8.swap_bytes(),
}

#[derive(Debug, Clone)]
#[repr(C, packed)]
struct Header {
op: DhcpType,
Expand Down Expand Up @@ -368,13 +370,26 @@ pub fn cvt(t: i32) -> io::Result<i32> {
}
}

fn get_nicname<'a>() -> &'a str {
static CACHED: Once<String> = Once::new();

CACHED.call_once(|| {
let nic_name = std::env::args().nth(1).unwrap_or(DEFAULT_NIC.to_string());

get_index(&nic_name)
.unwrap_or_else(|nic_name| panic!("[ DHCPD ] (EE) invalid NIC name {}", nic_name));

nic_name
})
}

fn get_macaddress<'a>() -> &'a [u8; 6] {
static CACHED: Once<[u8; 6]> = Once::new();
CACHED
.try_call_once(|| unsafe {
let fd = cvt(libc::socket(libc::AF_INET, libc::SOCK_DGRAM, 0))?;

let macaddr = IfReq::new(DEFAULT_NIC);
let macaddr = IfReq::new(get_nicname());
cvt(libc::ioctl(fd, libc::SIOCGIFHWADDR, &macaddr))?;

Ok::<[u8; 6], io::Error>(macaddr.macaddr())
Expand Down Expand Up @@ -467,9 +482,16 @@ fn configure(interface: &str, ip: Ipv4Addr, subnet_mask: Ipv4Addr) -> io::Result

const DEFAULT_NIC: &str = "eth0"; // FIXME: retrieve the default NIC from the kernel

fn get_index(nic: &str) -> io::Result<libc::c_uint> {
let ifname = std::ffi::CString::new(nic)?;
match unsafe { libc::if_nametoindex(ifname.as_ptr()) } {
0 => Err(io::Error::last_os_error()),
index => Ok(index),
}
}

pub fn main() -> Result<(), Box<dyn Error>> {
let socket = UdpSocket::bind(("0.0.0.0", 68))?;
socket.connect(("255.255.255.255", 67))?;
let socket = UdpSocket::bind(("0.0.0.0", DHCP_CLIENT_PORT))?;

let mut discover_header = Header::new(HType::Ethernet);
discover_header
Expand All @@ -479,7 +501,7 @@ pub fn main() -> Result<(), Box<dyn Error>> {
.set_host_name("Aero")
.set_parameter_request_list();

socket.send(discover_header.as_slice())?;
socket.send_to(discover_header.as_slice(), "255.255.255.255:67")?;

let mut offer = Header::new(HType::Ethernet);
socket.recv(offer.as_slice_mut())?;
Expand All @@ -495,7 +517,7 @@ pub fn main() -> Result<(), Box<dyn Error>> {
.set_host_name("Aero")
.set_parameter_request_list();

socket.send(request_header.as_slice())?;
socket.send_to(request_header.as_slice(), "255.255.255.255:67")?;

let mut ack = Header::new(HType::Ethernet);
socket.recv(ack.as_slice_mut())?;
Expand All @@ -519,7 +541,7 @@ pub fn main() -> Result<(), Box<dyn Error>> {
let subnet_mask = subnet_mask.unwrap();
let dns = dns.unwrap();

configure(DEFAULT_NIC, ack.your_ip, subnet_mask)?;
configure(get_nicname(), ack.your_ip, subnet_mask)?;

println!("[ DHCPD ] (!!) Configured:");
println!("[ DHCPD ] (!!) IP: {}", ack.your_ip);
Expand Down