benvin
66265764df
The agent now collects the device's reachable prefixes from the kernel FIB
(including FRR-installed routes) via 'ip route show' / 'ip -6 route show' and
reports them to the control plane (POST /devices/{name}/routes) alongside its
status. tomswallapi uses these to scope which routers enforce a rule. Route
parsing (default routes, ECMP nexthop lines, route-type keywords, host routes,
v4/v6) is unit-tested; collection degrades to nil without iproute2.
77 lines
2.1 KiB
Go
77 lines
2.1 KiB
Go
package agent
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import (
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"context"
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"os/exec"
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"strings"
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)
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// CollectFIB returns the device's reachable prefixes from the kernel FIB — which
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// includes FRR-installed routes — by shelling out to `ip route`. The control
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// plane uses these to scope which routers enforce a rule. On a host without
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// iproute2 it returns nil, and the control plane falls back to over-approximation.
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func CollectFIB(ctx context.Context) []string {
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var prefixes []string
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for _, spec := range []struct {
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args []string
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def string
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}{
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{[]string{"route", "show"}, "0.0.0.0/0"},
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{[]string{"-6", "route", "show"}, "::/0"},
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} {
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out, err := exec.CommandContext(ctx, "ip", spec.args...).Output()
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if err != nil {
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continue
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}
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prefixes = append(prefixes, parseRoutes(string(out), spec.def)...)
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}
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return dedup(prefixes)
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}
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// routeTypeKeywords are leading tokens in `ip route` output that precede the
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// actual destination (e.g. "unreachable 10.0.0.0/8").
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var routeTypeKeywords = map[string]bool{
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"unreachable": true, "blackhole": true, "prohibit": true, "throw": true,
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"local": true, "broadcast": true, "multicast": true, "anycast": true, "nat": true,
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}
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// parseRoutes extracts destination prefixes from `ip route show` output.
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// defaultPrefix is substituted for a "default" route (family-specific).
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func parseRoutes(output, defaultPrefix string) []string {
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var out []string
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for _, line := range strings.Split(output, "\n") {
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fields := strings.Fields(line)
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if len(fields) == 0 {
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continue
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}
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dst := fields[0]
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// ECMP routes emit continuation "nexthop ..." lines with no destination.
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if dst == "nexthop" {
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continue
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}
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if routeTypeKeywords[dst] {
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if len(fields) < 2 {
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continue
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}
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dst = fields[1]
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}
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if dst == "default" {
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out = append(out, defaultPrefix)
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continue
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}
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out = append(out, normalizePrefix(dst))
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}
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return out
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}
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// normalizePrefix turns a bare host address into a host prefix (/32 or /128).
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func normalizePrefix(dst string) string {
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if strings.Contains(dst, "/") {
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return dst
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}
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if strings.Contains(dst, ":") {
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return dst + "/128"
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}
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return dst + "/32"
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}
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