Initial commit: PXEForge Phases 1-4

Container-native PXE boot server in Rust, designed as a clean-room
alternative to iVentoy that never touches the client OS trust store.
This is the first commit of the project; it lands the full output of
Phases 1, 2, 3, and 4 in one shot.

## Phase 1 — protocol stack

- 8-crate workspace (core, dhcp-proxy, tftp, http-api, iso-store,
  ipxe-assets, webui, pxeforge bin).
- DHCP proxy (RFC 4578): replies with boot info only, never leases —
  sidesteps CAP_NET_RAW. Architecture-aware bootfile selection from
  option 93 (BIOS, IA32, x64-UEFI alias 0x0007/0x0009, ARM64).
- TFTP server with full OACK negotiation: blksize, tsize, windowsize.
  Without it a 1 MiB iPXE binary takes 2000 packets and unusably long.
- Two-stage iPXE chain: firmware PXE -> TFTP iPXE binary -> iPXE
  re-DHCPs with user-class iPXE -> HTTP /boot.ipxe -> kernel+initrd.
- HTTP server (axum) with byte-Range ISO streaming and an in-place
  ISO9660 lookup so kernel/initrd are served from inside the ISO
  without ever extracting it to disk.
- Linux ISOs boot via kernel+initrd extraction (memdisk/sanboot fail
  for >1-2 GiB modern distros). Distro-family detection drives the
  cmdline (Debian/Ubuntu, RHEL/Fedora, openSUSE, Arch, Alpine).

## Phase 2 — UX + Windows

- Hierarchical PXE menu (Default / Installers / Tools / Gated
  Deployment) generated from settings — no hand-written .ipxe paths
  surface in the UI. Number-key + letter hotkeys, BIOS+UEFI variants
  for some RHEL ISOs.
- Gated Deployment "horse-race" queue: clients join, operator picks
  one ISO, every gate launches simultaneously via tokio::sync::Notify.
- Bootimus-pattern Windows: WimPatcher injects a CRLF startnet.cmd
  into boot.wim so vanilla WinPE net-uses an SMB share and runs
  setup.exe. All Microsoft-signed; no test certs, no testsigning,
  no httpdisk.sys. SmbManager supervises smbd start/stop/SIGHUP.
- Netbox-style dark UI, fully offline (no CDN, no external fonts).

## Phase 3 — MVP hardening

- TFTP retransmit rewrite with explicit window tracking — UEFI SNP
  clients no longer hang on files that end mid-window. 4 new tests.
- DHCP broadcast-flag honored per RFC 2131 §4.1.
- Multi-arch container (linux/amd64 + linux/arm64). Entrypoint chowns
  bind-mounts as root then drops to uid 10001 via gosu.
- /healthz + /readyz split from /api/status — readyz fails if no
  iPXE binaries are bundled.
- pxeforge seed --from <path> CLI: same pipeline as web upload (slug,
  sha256, introspection, boot-entry).
- All timestamps RFC 3339 (browser Date couldn't parse the 9-tuple).
- Gate poll retains assignment until operator releases — clients that
  retry on transient network errors reuse the assignment instead of
  falling back to the menu.
- Custom OpenShift SCC: hostNetwork + NET_BIND_SERVICE only, no
  NET_RAW.

## Phase 4 — UI restructure + remote storage

- Web UI rebuilt around six tabs inspired by the iVentoy layout:
  Dashboard / Network / Forge Gate / Storage / Terminal / About.
  Old "Monitoring/Content/Configuration" sidebar groups are gone.
- NFS share manager (crates/iso-store/src/nfs.rs): mount NFSv3 or
  NFSv4.1 shares as ISO sources instead of uploading every file
  into the PVC. New IsoSource enum on IsoMeta lets the store resolve
  Local vs NFS lazily. Persisted to <work_dir>/nfs.json; failed
  mounts surface in the UI rather than blocking startup.
- Dockerfile gains nfs-common + iproute2; mounting NFS in-container
  also requires CAP_SYS_ADMIN. Documented in docs/architecture.md.
- LogBus + tracing layer in core: 500-line ring buffer + broadcast
  channel feed an SSE endpoint at /api/log/stream.
- Operator terminal at /api/terminal: whitelisted commands (status,
  isos, clients, gate, nfs, smb, log) — deliberately not a shell.
  Output mirrored onto the LogBus so the live tail and the terminal
  pane share one timeline.
- Network tab: read-only nic_name / subnet_mask / gateway probed
  from `ip` at startup; only DNS server is editable. Editing IP/mask
  on a hot UI would silently break PXE for every client mid-boot.
- Bootimus parity (releases v0.1.55 -> v0.1.62): amber row tint on
  un-bootable ISOs with inline reasons, dashboard "won't boot" panel.

## Tests

56 tests passing across the workspace:
- 16 core (LogBus, gate, settings, arch, client)
- 1 dhcp-proxy (raw option-93 extraction)
- 8 http-api unit (range parsing, terminal split/format)
- 13 http-api integration (gated deployment, range, settings, NFS,
  terminal, log SSE, network endpoint, ui assets, no-external-urls)
- 12 iso-store (introspect, slugify, smb, windows wim, NFS options)
- 6 tftp (RRQ parsing, plan_window edges)

cargo build --workspace and cargo clippy --workspace --all-targets
both finish clean (warnings only, no errors).

crates/core/src/config.rs

@@ -0,0 +1,168 @@
+use serde::{Deserialize, Serialize};
+use std::net::{IpAddr, Ipv4Addr};
+use std::path::{Path, PathBuf};
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+#[serde(default)]
+pub struct Config {
+    pub server: ServerConfig,
+    pub network: NetworkConfig,
+    pub paths: Paths,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+#[serde(default)]
+pub struct ServerConfig {
+    /// Address the web/API server binds to.
+    pub http_bind: IpAddr,
+    /// Port for the web/API + ISO/iPXE HTTP server (single port, multiplexed by path).
+    pub http_port: u16,
+    /// Address the TFTP server binds to.
+    pub tftp_bind: IpAddr,
+    /// Port for TFTP (RFC 1350 default is 69).
+    pub tftp_port: u16,
+    /// External hostname/IP clients should use to reach this server. If
+    /// `None`, auto-detect from the interface that received the DHCP request
+    /// (via IP_PKTINFO). This is what ends up in DHCP option 54 / siaddr,
+    /// option 66 (TFTP server), and the base of generated iPXE URLs.
+    pub public_ip: Option<Ipv4Addr>,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+#[serde(default)]
+pub struct NetworkConfig {
+    pub dhcp_mode: DhcpMode,
+    /// Address the DHCP proxy/server binds to. For proxy mode, usually 0.0.0.0.
+    pub dhcp_bind: IpAddr,
+    /// UDP port for DHCP server-side receive. Standard is 67.
+    pub dhcp_port: u16,
+    /// UDP port for PXE Boot Server discovery. Standard is 4011.
+    pub pxe_port: u16,
+    /// Optional allowlist of client MAC prefixes (OUI). Empty = serve everyone.
+    pub mac_allowlist: Vec<String>,
+    /// Optional allowlist of subnets (CIDR). Empty = serve everyone.
+    pub subnet_allowlist: Vec<String>,
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize, Default)]
+#[serde(rename_all = "lowercase")]
+pub enum DhcpMode {
+    /// Run as DHCP proxy (RFC 4578): reply with boot info only, don't lease
+    /// IPs. Coexists with an existing DHCP server on the network. Default
+    /// because it's the only mode that works in most real deployments without
+    /// taking over address assignment.
+    #[default]
+    Proxy,
+    /// Disabled — rely on an external DHCP server that has been manually
+    /// configured with `next-server` / `filename`. PXEForge only serves TFTP
+    /// + HTTP in this mode. Useful for home routers that can be pre-set.
+    Disabled,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+#[serde(default)]
+pub struct Paths {
+    /// Directory holding uploaded ISO files.
+    pub iso_dir: PathBuf,
+    /// Directory for extracted kernel/initrd and other per-ISO derived assets.
+    pub work_dir: PathBuf,
+    /// Directory containing bundled iPXE binaries (undionly.kpxe, snponly.efi, ...).
+    pub ipxe_dir: PathBuf,
+    /// Path to the wimboot binary for Windows ISOs (optional — feature-gated).
+    pub wimboot_path: Option<PathBuf>,
+    /// Directory under which Windows ISOs are extracted and served via SMB.
+    /// Only used when `settings.windows_enabled = true`. Defaults to
+    /// `/var/lib/pxeforge/smb` in the container image.
+    pub smb_dir: PathBuf,
+}
+
+impl Default for ServerConfig {
+    fn default() -> Self {
+        Self {
+            http_bind: IpAddr::V4(Ipv4Addr::UNSPECIFIED),
+            http_port: 80,
+            tftp_bind: IpAddr::V4(Ipv4Addr::UNSPECIFIED),
+            tftp_port: 69,
+            public_ip: None,
+        }
+    }
+}
+
+impl Default for NetworkConfig {
+    fn default() -> Self {
+        Self {
+            dhcp_mode: DhcpMode::Proxy,
+            dhcp_bind: IpAddr::V4(Ipv4Addr::UNSPECIFIED),
+            dhcp_port: 67,
+            pxe_port: 4011,
+            mac_allowlist: Vec::new(),
+            subnet_allowlist: Vec::new(),
+        }
+    }
+}
+
+impl Default for Paths {
+    fn default() -> Self {
+        Self {
+            iso_dir: PathBuf::from("/var/lib/pxeforge/isos"),
+            work_dir: PathBuf::from("/var/lib/pxeforge/work"),
+            ipxe_dir: PathBuf::from("/usr/share/pxeforge/ipxe"),
+            wimboot_path: None,
+            smb_dir: PathBuf::from("/var/lib/pxeforge/smb"),
+        }
+    }
+}
+
+impl Default for Config {
+    fn default() -> Self {
+        Self {
+            server: ServerConfig::default(),
+            network: NetworkConfig::default(),
+            paths: Paths::default(),
+        }
+    }
+}
+
+impl Config {
+    pub fn from_toml_file(path: &Path) -> crate::Result<Self> {
+        let text = std::fs::read_to_string(path)?;
+        toml::from_str(&text).map_err(|e| crate::Error::Config(e.to_string()))
+    }
+
+    /// Apply environment variable overrides. Env var names follow the pattern
+    /// `PXEFORGE_<SECTION>_<FIELD>`, uppercase. Unknown vars are ignored.
+    /// Call this after loading the TOML file so env takes precedence.
+    pub fn apply_env(&mut self) {
+        if let Ok(v) = std::env::var("PXEFORGE_HTTP_PORT") {
+            if let Ok(p) = v.parse() { self.server.http_port = p; }
+        }
+        if let Ok(v) = std::env::var("PXEFORGE_TFTP_PORT") {
+            if let Ok(p) = v.parse() { self.server.tftp_port = p; }
+        }
+        if let Ok(v) = std::env::var("PXEFORGE_DHCP_PORT") {
+            if let Ok(p) = v.parse() { self.network.dhcp_port = p; }
+        }
+        if let Ok(v) = std::env::var("PXEFORGE_PUBLIC_IP") {
+            if let Ok(ip) = v.parse() { self.server.public_ip = Some(ip); }
+        }
+        if let Ok(v) = std::env::var("PXEFORGE_DHCP_MODE") {
+            self.network.dhcp_mode = match v.to_ascii_lowercase().as_str() {
+                "proxy" => DhcpMode::Proxy,
+                "disabled" | "off" | "none" => DhcpMode::Disabled,
+                _ => self.network.dhcp_mode,
+            };
+        }
+        if let Ok(v) = std::env::var("PXEFORGE_ISO_DIR") {
+            self.paths.iso_dir = PathBuf::from(v);
+        }
+        if let Ok(v) = std::env::var("PXEFORGE_WORK_DIR") {
+            self.paths.work_dir = PathBuf::from(v);
+        }
+        if let Ok(v) = std::env::var("PXEFORGE_IPXE_DIR") {
+            self.paths.ipxe_dir = PathBuf::from(v);
+        }
+        if let Ok(v) = std::env::var("PXEFORGE_SMB_DIR") {
+            self.paths.smb_dir = PathBuf::from(v);
+        }
+    }
+}