f-29: watchdog: add checksubnet #29

Signed-off-by: GnomeZworc <nicolas.boufidjeline@g3e.fr>

internal/watchdog/check_subnet.go

@@ -0,0 +1,134 @@
+package watchdog
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+
+	"git.g3e.fr/syonad/two/internal/dhcp"
+	"git.g3e.fr/syonad/two/internal/netns"
+	"git.g3e.fr/syonad/two/internal/state"
+	"git.g3e.fr/syonad/two/internal/watchdog/notify"
+	"git.g3e.fr/syonad/two/pkg/db/kv"
+
+	"github.com/dgraph-io/badger/v4"
+)
+
+const (
+	modeVxlan  = "vxlan"
+	modeBridge = "bridge"
+)
+
+func subnetIfaceNames(subnetName string) (hostVeth, nsVeth, bridge string, err error) {
+	parts := strings.SplitN(subnetName, "-", 2)
+	if len(parts) < 2 || parts[1] == "" {
+		return "", "", "", fmt.Errorf("nom de subnet %q sans identifiant après le tiret, interfaces indéductibles", subnetName)
+	}
+	id := parts[1]
+	return "v-" + id + "-e", "v-" + id + "-i", "br-" + id, nil
+}
+
+func dnsmasqName(vpc, bridge string) string {
+	return vpc + "_" + bridge
+}
+
+func CheckSubnets(db *badger.DB, u unitChecker, n notify.Notifier) error {
+	pairs, err := kv.ListByPrefix(db, prefixSubnet)
+	if err != nil {
+		return fmt.Errorf("watchdog: lecture des subnets: %w", err)
+	}
+
+	for _, name := range resourceNames(pairs, prefixSubnet) {
+		st, err := state.Get(db, prefixSubnet+name)
+		if err != nil {
+			n.Notify(kindSubnet, name, fmt.Sprintf("état illisible en base: %v", err))
+			continue
+		}
+		if st != state.Running {
+			continue
+		}
+		checkSubnet(db, name, u, n)
+	}
+	return nil
+}
+
+func checkSubnet(db *badger.DB, name string, u unitChecker, n notify.Notifier) {
+	hostVeth, nsVeth, bridge, err := subnetIfaceNames(name)
+	if err != nil {
+		n.Notify(kindSubnet, name, err.Error())
+		return
+	}
+
+	vpc, err := kv.GetFromDB(db, prefixSubnet+name+"/vpc")
+	if err != nil {
+		n.Notify(kindSubnet, name, fmt.Sprintf("vpc illisible en base: %v", err))
+		return
+	}
+
+	mode, err := kv.GetFromDB(db, prefixSubnet+name+"/mode")
+	if err != nil {
+		n.Notify(kindSubnet, name, fmt.Sprintf("mode illisible en base: %v", err))
+		return
+	}
+
+	if p := linkProblem(hostVeth); p != "" {
+		n.Notify(kindSubnet, name, p)
+	}
+
+	switch mode {
+	case modeVxlan:
+		if p := linkProblem(bridge); p != "" {
+			n.Notify(kindSubnet, name, p+" (host)")
+		}
+		checkVxlanIface(db, name, n)
+	case modeBridge:
+	default:
+		n.Notify(kindSubnet, name, fmt.Sprintf("mode inconnu %q", mode))
+	}
+
+	checkSubnetNetns(name, vpc, nsVeth, bridge, n)
+
+	dnsName := dnsmasqName(vpc, bridge)
+	conf := filepath.Join(dhcp.DefaultConfDir, dnsName+".conf")
+	if _, err := os.Stat(conf); err != nil {
+		n.Notify(kindSubnet, name, fmt.Sprintf("config dnsmasq absente (%s): %v", conf, err))
+	}
+
+	checkUnit(kindSubnet, name, "dnsmasq@"+dnsName+".service", u, n)
+}
+
+func checkVxlanIface(db *badger.DB, name string, n notify.Notifier) {
+	raw, err := kv.GetFromDB(db, prefixSubnet+name+"/vxlan_id")
+	if err != nil {
+		n.Notify(kindSubnet, name, fmt.Sprintf("vxlan_id illisible en base: %v", err))
+		return
+	}
+	id, err := strconv.Atoi(raw)
+	if err != nil {
+		n.Notify(kindSubnet, name, fmt.Sprintf("vxlan_id invalide %q: %v", raw, err))
+		return
+	}
+	if p := linkProblem(fmt.Sprintf("vxlan-%d", id)); p != "" {
+		n.Notify(kindSubnet, name, p)
+	}
+}
+
+func checkSubnetNetns(name, vpc, nsVeth, bridge string, n notify.Notifier) {
+	if !netns.Exist(vpc) {
+		n.Notify(kindSubnet, name, "netns "+vpc+" absent (/var/run/netns/"+vpc+")")
+		return
+	}
+
+	if err := netns.Call(vpc, func() error {
+		for _, iface := range []string{nsVeth, bridge} {
+			if p := linkProblem(iface); p != "" {
+				n.Notify(kindSubnet, name, p+" (dans le netns "+vpc+")")
+			}
+		}
+		return nil
+	}); err != nil {
+		n.Notify(kindSubnet, name, fmt.Sprintf("entrée dans le netns %s impossible: %v", vpc, err))
+	}
+}