Files
housecarl/internal/web/static/assets/pages/trace.js
T
abrown38andClaude Opus 5.5 de075edd5d Shadow mode: Housecarl beside the firewall in force, changing nothing
shadow.enabled in housecarl.yaml loads Housecarl's ruleset so that it
blocks, rejects and translates nothing: drops and rejects count and
accept (an accept only ends Housecarl's chain), policies accept and log
what they would drop, NAT only counts, MSS clamping and the flowtable
are left out, and raw rules that do more than accept, drop or reject are
left out with a warning. Comments mark what would happen ([would drop]).
Filter chains run after the other firewall's (+10) or before (-10); NAT
chains always first. Every change is checked by nftables in both forms.
No probation; takeovers and closing connections are refused. The boot
fallback filters nothing. internal/tablewatch puts the table back after
a flush ruleset. Mode in status, healthz, whoami, the web UI, the log
and the tracer; hc ruleset --enforcing. docs/shadow.md.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-20 18:11:01 +01:00

80 lines
5.2 KiB
JavaScript

// Trace: follow packets through every table's rules, and see what
// decided their fate.
import { h, mount, input, select, field, errorBox, badge } from "../ui.js";
import { get, api, can } from "../api.js";
import { onLeave } from "../app.js";
export async function render(el, params, query) {
const address = input({ placeholder: "192.168.1.50, or 2001:db8:1::/64", class: "mono", value: (query && query.get && query.get("address")) || "" });
const port = input({ placeholder: "443", class: "short", type: "number", min: 1, max: 65535 });
const protocol = select([["", "any"], "tcp", "udp", "sctp", "icmp", "icmpv6"], "", { class: "inline" });
const seconds = input({ value: "60", class: "short", type: "number", min: 5, max: 600 });
const err = h("div");
const status = h("div");
const packets = h("div");
const write = can("config", true);
const startBtn = h("button", { class: "primary", onclick: start }, "Start tracing");
const stopBtn = h("button", { class: "hidden", onclick: stop }, "Stop");
let timer = null;
async function start() {
mount(err);
try {
await api("POST", "/trace", { body: { address: address.value.trim(), port: parseInt(port.value || "0", 10), protocol: protocol.value, seconds: parseInt(seconds.value || "60", 10) } });
poll();
} catch (e) { mount(err, errorBox(e)); }
}
async function stop() {
try { show(await api("DELETE", "/trace")); } catch (e) { mount(err, errorBox(e)); }
}
async function poll() {
clearTimeout(timer);
let st;
try { st = await get("/trace"); } catch (e) { mount(err, errorBox(e)); return; }
show(st);
if (st.running) timer = setTimeout(poll, 1000);
}
function show(st) {
startBtn.classList.toggle("hidden", st.running || !write);
stopBtn.classList.toggle("hidden", !st.running || !write);
const what = [st.input.address, st.input.protocol, st.input.port ? "port " + st.input.port : ""].filter(Boolean).join(" ");
mount(status, st.started && st.started !== "0001-01-01T00:00:00Z" ? h("div", { class: "msg " + (st.error ? "err" : st.running ? "info" : "ok") },
st.running ? ["Tracing ", h("strong", null, what), " until " + new Date(st.ends).toLocaleTimeString() + ". Make the traffic happen now."]
: ["Traced ", h("strong", null, what), ": " + (st.packets.length === 1 ? "1 packet" : st.packets.length + " packets") + "."],
st.error ? h("div", null, st.error) : null) : null);
mount(packets, st.packets.length ? st.packets.slice().reverse().map(packet)
: st.running ? h("div", { class: "empty" }, "No packets yet.") : null);
}
const hostPort = (a, p) => !a ? "" : !p ? a : a.includes(":") ? "[" + a + "]:" + p : a + ":" + p;
function packet(p) {
const head = [p.protocol, p.tcp_flags, p.icmp_type].filter(Boolean).join(" ");
const decided = p.decided_by.label || [p.decided_by.table, p.decided_by.chain, p.decided_by.kind].filter(Boolean).join(" ");
return h("div", { class: "panel trace-packet" },
h("div", { class: "trace-head" },
badge(p.verdict, p.verdict === "dropped" ? "err" : "ok"), " ",
h("span", { class: "mono" }, hostPort(p.source, p.source_port), " → ", hostPort(p.destination, p.destination_port)), " ",
h("span", { class: "muted" }, head, p.in ? " · in " + p.in : "", p.out ? " · out " + p.out : ""),
h("span", { class: "muted small trace-time" }, new Date(p.time).toLocaleTimeString())),
decided ? h("div", { class: "small" }, p.verdict === "dropped" ? "Dropped by " : "Accepted by ", h("strong", null, decided)) : null,
p.would_drop ? h("div", { class: "small" }, badge("shadow mode", "warn"), " Housecarl would have dropped it: ",
h("strong", null, p.would_drop.label || [p.would_drop.chain, p.would_drop.mark].filter(Boolean).join(" "))) : null,
h("table", { class: "trace-steps" }, h("tbody", null, p.steps.map((s) => h("tr", { class: /^(drop|reject)/.test(s.verdict) || /\[would (drop|reject)\]/.test(s.rule || "") ? "step-drop" : s.verdict === "accept" ? "step-accept" : "" },
h("td", { class: "muted small" }, s.table + " " + s.chain),
h("td", null, s.label ? (s.mark && s.mark.startsWith("r") ? h("a", { href: "#/rules?chain=" + s.chain }, s.label) : s.label)
: s.kind === "policy" ? s.chain + " policy" : h("span", { class: "mono small" }, s.rule)),
h("td", { class: "small" }, s.verdict))))));
}
mount(el,
h("div", { class: "page-head" }, h("div", { class: "grow" }, h("h1", null, "Trace"),
h("div", { class: "muted" }, "Follows packets through the whole ruleset, Housecarl's rules and every other table (Docker, fail2ban…): each rule and policy they meet, and what accepted or dropped them. For “why doesn't this get through?”"))),
write ? h("div", { class: "panel" }, h("div", { class: "form-grid" },
field("Address", address, "Packets from or to it (either way). An address or a prefix."),
field("Port", h("div", null, port, " ", protocol), "Packets from or to it. Empty: any."),
field("For", h("div", null, seconds, " seconds"), "At most 600; it stops by itself after 200 packets.")),
h("div", { class: "actions form-actions" }, startBtn, stopBtn), err) : null,
status, packets);
await poll();
onLeave(() => clearTimeout(timer));
}