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add snmpv3 topology discovery with q-bridge support

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This commit is contained in:
Ian Gulliver
2025-11-29 21:56:45 -08:00
parent c780fba93c
commit f4972b2b50
3 changed files with 105 additions and 46 deletions
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133
snmp.go
View File

@@ -3,22 +3,36 @@ package tendrils
import (
"context"
"fmt"
"log"
"net"
"regexp"
"strings"
"time"
"github.com/gosnmp/gosnmp"
)
var (
addToParentRules = []*regexp.Regexp{
regexp.MustCompile(`CPU Interface`),
}
portNameRewrites = []struct {
regex *regexp.Regexp
replacement string
}{
{regexp.MustCompile(`Slot: (\d+) Port: (\d+) .+`), "$1/$2"},
}
)
type snmpConfig struct {
username string
authKey string
privKey string
authProto gosnmp.SnmpV3AuthProtocol
privProto gosnmp.SnmpV3PrivProtocol
secLevel gosnmp.SnmpV3MsgFlags
timeout time.Duration
retries int
username string
authKey string
privKey string
authProto gosnmp.SnmpV3AuthProtocol
privProto gosnmp.SnmpV3PrivProtocol
secLevel gosnmp.SnmpV3MsgFlags
timeout time.Duration
retries int
}
func defaultSNMPConfig() *snmpConfig {
@@ -63,7 +77,7 @@ func (t *Tendrils) connectSNMP(ip net.IP) (*gosnmp.GoSNMP, error) {
}
func (t *Tendrils) pollSNMP(ctx context.Context) {
ticker := time.NewTicker(5 * time.Minute)
ticker := time.NewTicker(10 * time.Second)
defer ticker.Stop()
t.querySwitches()
@@ -112,55 +126,90 @@ func (t *Tendrils) queryBridgeMIB(snmp *gosnmp.GoSNMP, deviceIP net.IP) {
return
}
if len(macResults) == 0 {
macOID = "1.3.6.1.2.1.17.7.1.2.2.1.1"
portOID = "1.3.6.1.2.1.17.7.1.2.2.1.2"
macResults, err = snmp.BulkWalkAll(macOID)
if err != nil {
return
}
}
portResults, err := snmp.BulkWalkAll(portOID)
if err != nil {
return
}
portMap := make(map[string]int)
type macPortEntry struct {
mac net.HardwareAddr
bridgePort int
}
var macPorts []macPortEntry
for _, result := range portResults {
if result.Type == gosnmp.Integer {
oidSuffix := result.Name[len(portOID)+1:]
portMap[oidSuffix] = result.Value.(int)
oidSuffix := strings.TrimPrefix(result.Name[len(portOID):], ".")
parts := strings.Split(oidSuffix, ".")
if len(parts) >= 8 {
var macBytes []byte
for j := 2; j <= 7; j++ {
var b int
fmt.Sscanf(parts[j], "%d", &b)
macBytes = append(macBytes, byte(b))
}
if len(macBytes) == 6 {
mac := net.HardwareAddr(macBytes)
bridgePort := result.Value.(int)
macPorts = append(macPorts, macPortEntry{mac: mac, bridgePort: bridgePort})
}
}
}
}
bridgePortToIfIndex := t.getBridgePortMapping(snmp)
ifNames := t.getInterfaceNames(snmp)
for _, result := range macResults {
if result.Type == gosnmp.OctetString {
macBytes := result.Value.([]byte)
if len(macBytes) != 6 {
continue
}
for _, entry := range macPorts {
mac := entry.mac
bridgePort := entry.bridgePort
mac := net.HardwareAddr(macBytes)
if isBroadcastOrZero(mac) {
continue
}
if isBroadcastOrZero(mac) {
continue
}
oidSuffix := result.Name[len(macOID)+1:]
bridgePort, exists := portMap[oidSuffix]
if !exists {
continue
}
ifIndex, exists := bridgePortToIfIndex[bridgePort]
if !exists {
ifIndex = bridgePort
}
ifIndex, exists := bridgePortToIfIndex[bridgePort]
if !exists {
ifIndex = bridgePort
}
ifName := ifNames[ifIndex]
if ifName == "" {
ifName = "??"
}
ifName := ifNames[ifIndex]
if ifName == "" {
ifName = "??"
addToParent := false
for _, rule := range addToParentRules {
if rule.MatchString(ifName) {
addToParent = true
break
}
}
t.nodes.Update(nil, []net.HardwareAddr{mac}, ifName, "", "snmp")
for _, rewrite := range portNameRewrites {
if rewrite.regex.MatchString(ifName) {
ifName = rewrite.regex.ReplaceAllString(ifName, rewrite.replacement)
break
}
}
if addToParent {
t.nodes.Update([]net.IP{deviceIP}, []net.HardwareAddr{mac}, "", "", "snmp")
} else {
t.nodes.UpdateWithParent(deviceIP, nil, []net.HardwareAddr{mac}, ifName, "", "snmp")
}
}
log.Printf("[snmp] queried bridge mib on %s", deviceIP)
}
func (t *Tendrils) queryARPTable(snmp *gosnmp.GoSNMP, deviceIP net.IP) {
@@ -231,11 +280,9 @@ func (t *Tendrils) queryARPTable(snmp *gosnmp.GoSNMP, deviceIP net.IP) {
ifName = "??"
}
t.nodes.Update(ips, []net.HardwareAddr{mac}, ifName, "", "snmp")
t.nodes.UpdateWithParent(deviceIP, ips, []net.HardwareAddr{mac}, ifName, "", "snmp")
}
}
log.Printf("[snmp] queried arp table on %s", deviceIP)
}
func (t *Tendrils) getBridgePortMapping(snmp *gosnmp.GoSNMP) map[int]int {
@@ -249,7 +296,7 @@ func (t *Tendrils) getBridgePortMapping(snmp *gosnmp.GoSNMP) map[int]int {
mapping := make(map[int]int)
for _, result := range results {
if result.Type == gosnmp.Integer {
oidParts := result.Name[len(oid)+1:]
oidParts := strings.TrimPrefix(strings.TrimPrefix(result.Name, "."+oid), ".")
var bridgePort int
_, err := fmt.Sscanf(oidParts, "%d", &bridgePort)
if err != nil {
@@ -274,7 +321,7 @@ func (t *Tendrils) getInterfaceNames(snmp *gosnmp.GoSNMP) map[int]string {
names := make(map[int]string)
for _, result := range results {
if result.Type == gosnmp.OctetString {
oidParts := result.Name[len(oid)+1:]
oidParts := strings.TrimPrefix(strings.TrimPrefix(result.Name, "."+oid), ".")
var ifIndex int
_, err := fmt.Sscanf(oidParts, "%d", &ifIndex)
if err != nil {