Red Bear OS
bd595851e2
251 files: init, acpid, ipcd, netcfg, ihdgd, virtio-gpud, scheme-utils, inputd, block driver, ptyd, ramfs, randd, initfs bootstrap, path deps, version +rb0.3.1, author attribution
73 lines
2.0 KiB
Rust
73 lines
2.0 KiB
Rust
use std::collections::btree_map::{BTreeMap, Entry};
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pub struct PortSet {
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from: u16,
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range: u16,
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next: u16,
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ports: BTreeMap<u16, usize>,
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}
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impl PortSet {
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pub fn new(from: u16, to: u16) -> Option<PortSet> {
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if from > to {
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return None;
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}
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Some(PortSet {
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from,
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range: to - from + 1,
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next: 0,
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ports: BTreeMap::new(),
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})
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}
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pub fn get_port(&mut self) -> Option<u16> {
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if self.ports.len() >= self.range as usize {
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return None;
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}
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let port = loop {
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if let Entry::Vacant(entry) = self.ports.entry(self.next) {
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entry.insert(1);
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let port = self.from + self.next;
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self.next = self.next.wrapping_add(1);
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break port;
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}
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self.next = self.next.wrapping_add(1);
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};
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Some(port)
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}
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pub fn claim_port(&mut self, port: u16) -> bool {
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if let Entry::Vacant(entry) = self.ports.entry(port) {
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entry.insert(1);
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true
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} else {
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false
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}
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}
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/// Increment the reference count for an already-claimed port (SO_REUSEADDR).
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/// Always succeeds: the caller has indicated SO_REUSEADDR is set, so
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/// multiple sockets are allowed to bind to the same port. The actual
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/// collision check (returning EADDRINUSE) is done by `claim_port` first.
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/// Returns true on success.
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pub fn claim_port_reuse(&mut self, port: u16) -> bool {
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self.ports.entry(port).and_modify(|c| *c += 1).or_insert(1);
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true
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}
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pub fn acquire_port(&mut self, port: u16) {
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*self.ports.entry(port).or_insert(0) += 1;
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}
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pub fn release_port(&mut self, port: u16) {
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if let Entry::Occupied(mut entry) = self.ports.entry(port) {
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*entry.get_mut() -= 1;
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if *entry.get() == 0 {
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entry.remove();
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}
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}
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}
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}
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