fix(traffic): записывать потоки при подмене UDP-источника в Docker

Пакеты IPFIX доходили, но разговоры отбрасывались, если Docker подменял адрес jump-host на 172.x.

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/src/services/traffic-flow-parse.ts

@@ -24,6 +24,48 @@ function ipv4(buf: Buffer, offset: number): string {
   return `${buf[offset]}.${buf[offset + 1]}.${buf[offset + 2]}.${buf[offset + 3]}`
 }
 
+function ipv6(buf: Buffer, offset: number): string {
+  const parts: string[] = []
+  for (let i = 0; i < 8; i++) parts.push(buf.readUInt16BE(offset + i * 2).toString(16))
+  return parts.join(":")
+}
+
+const VAR_LEN = 0xffff
+
+function consumeField(
+  buf: Buffer,
+  off: number,
+  length: number,
+  limit: number,
+): { data: Buffer; next: number } | null {
+  if (length === VAR_LEN) {
+    if (off >= limit) return null
+    const first = buf[off]!
+    if (first < 255) {
+      const end = off + 1 + first
+      if (end > limit) return null
+      return { data: buf.subarray(off + 1, end), next: end }
+    }
+    if (off + 3 > limit) return null
+    const len = buf.readUInt16BE(off + 1)
+    const end = off + 3 + len
+    if (end > limit) return null
+    return { data: buf.subarray(off + 3, end), next: end }
+  }
+  const end = off + length
+  if (end > limit) return null
+  return { data: buf.subarray(off, end), next: end }
+}
+
+function fixedRecordSize(fields: FieldSpec[]): number | null {
+  let n = 0
+  for (const f of fields) {
+    if (f.length === VAR_LEN) return null
+    n += f.length
+  }
+  return n
+}
+
 function readUint(buf: Buffer, offset: number, length: number): number {
   if (length === 1) return buf.readUInt8(offset)
   if (length === 2) return buf.readUInt16BE(offset)
@@ -87,7 +129,12 @@ function parseIpfixTemplates(exporter: string, buf: Buffer, setStart: number, se
   templatesByExporter.set(exporter, map)
 }
 
-function recordFromFields(fields: FieldSpec[], buf: Buffer, offset: number): { flow: ParsedFlow; next: number } | null {
+function recordFromFields(
+  fields: FieldSpec[],
+  buf: Buffer,
+  offset: number,
+  limit: number,
+): { flow: ParsedFlow; next: number } | null {
   let off = offset
   let src = ""
   let dst = ""
@@ -98,41 +145,78 @@ function recordFromFields(fields: FieldSpec[], buf: Buffer, offset: number): { f
   let packets = 0
   let inIface = ""
   for (const f of fields) {
-    if (off + f.length > buf.length) return null
+    const field = consumeField(buf, off, f.length, limit)
+    if (!field) return null
+    const { data } = field
     switch (f.type) {
       case 8:
-        if (f.length === 4) src = ipv4(buf, off)
+        if (data.length === 4) src = ipv4(data, 0)
         break
       case 12:
-        if (f.length === 4) dst = ipv4(buf, off)
+        if (data.length === 4) dst = ipv4(data, 0)
+        break
+      case 27:
+        if (data.length === 16 && !src) src = ipv6(data, 0)
+        break
+      case 28:
+        if (data.length === 16 && !dst) dst = ipv6(data, 0)
+        break
+      case 225:
+        if (data.length === 4 && !src) src = ipv4(data, 0)
+        break
+      case 226:
+        if (data.length === 4 && !dst) dst = ipv4(data, 0)
         break
       case 4:
-        proto = readUint(buf, off, f.length)
+        proto = readUint(data, 0, data.length)
         break
       case 7:
-        srcPort = readUint(buf, off, f.length)
+        srcPort = readUint(data, 0, data.length)
         break
       case 11:
-        dstPort = readUint(buf, off, f.length)
+        dstPort = readUint(data, 0, data.length)
         break
       case 1:
-        bytes = readUint(buf, off, f.length)
+        bytes = readUint(data, 0, data.length)
         break
       case 2:
-        packets = readUint(buf, off, f.length)
+        packets = readUint(data, 0, data.length)
+        break
+      case 85:
+        if (!bytes) bytes = readUint(data, 0, data.length)
+        break
+      case 86:
+        if (!packets) packets = readUint(data, 0, data.length)
         break
       case 10:
-        inIface = String(readUint(buf, off, f.length))
+        inIface = String(readUint(data, 0, data.length))
         break
       default:
         break
     }
-    off += f.length
+    off = field.next
   }
-  if (!src && !dst) return { flow: { src, dst, proto, srcPort, dstPort, bytes, packets, inIface }, next: off }
   return { flow: { src, dst, proto, srcPort, dstPort, bytes, packets, inIface }, next: off }
 }
 
+function parseDataRecords(
+  tpl: Template,
+  buf: Buffer,
+  recOff: number,
+  setEnd: number,
+  out: ParsedFlow[],
+) {
+  const size = fixedRecordSize(tpl.fields)
+  while (recOff + 1 < setEnd) {
+    if (size != null && recOff + size > setEnd) break
+    const parsed = recordFromFields(tpl.fields, buf, recOff, setEnd)
+    if (!parsed) break
+    if (parsed.flow.src || parsed.flow.dst) out.push(parsed.flow)
+    if (parsed.next <= recOff) break
+    recOff = parsed.next
+  }
+}
+
 function parseIpfix(buf: Buffer, exporter: string): ParsedFlow[] {
   if (buf.length < 16) return []
   const total = buf.readUInt16BE(2)
@@ -148,16 +232,7 @@ function parseIpfix(buf: Buffer, exporter: string): ParsedFlow[] {
       parseIpfixTemplates(exporter, buf, off, setEnd, setId)
     } else if (setId >= 256) {
       const tpl = templatesByExporter.get(exporter)?.get(setId)
-      if (tpl) {
-        let recOff = off + 4
-        while (recOff + 1 < setEnd) {
-          const parsed = recordFromFields(tpl.fields, buf, recOff)
-          if (!parsed) break
-          if (parsed.flow.src || parsed.flow.dst) out.push(parsed.flow)
-          if (parsed.next <= recOff) break
-          recOff = parsed.next
-        }
-      }
+      if (tpl) parseDataRecords(tpl, buf, off + 4, setEnd, out)
     }
     off = setEnd
   }
@@ -191,16 +266,7 @@ function parseNetflowV9(buf: Buffer, exporter: string): ParsedFlow[] {
       templatesByExporter.set(exporter, map)
     } else if (setId >= 256) {
       const tpl = map.get(setId)
-      if (tpl) {
-        let recOff = off + 4
-        while (recOff + 1 < setEnd) {
-          const parsed = recordFromFields(tpl.fields, buf, recOff)
-          if (!parsed) break
-          if (parsed.flow.src || parsed.flow.dst) out.push(parsed.flow)
-          if (parsed.next <= recOff) break
-          recOff = parsed.next
-        }
-      }
+      if (tpl) parseDataRecords(tpl, buf, off + 4, setEnd, out)
     }
     off = setEnd
   }