feat(traffic-flow): add NAT fields to flow processing and analytics

- Introduced new fields for NAT source and destination IPs, as well as their respective ports, in the flow data model.
- Updated database schema and migration scripts to accommodate the new NAT fields in the `flow_buckets` table.
- Enhanced flow analytics and processing functions to utilize the new NAT fields, improving accuracy in traffic flow analysis.
- Added tests to validate the handling of NAT data in various scenarios, ensuring robustness in flow processing.

Co-authored-by: Cursor <[email protected]>

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

@@ -182,6 +182,95 @@ resetFlowTemplatesForTests()
   assert.equal(extra[0]?.bytes, 1500)
 }
 
+resetFlowTemplatesForTests()
+{
+  const fieldSpecs: Array<[number, number]> = [
+    [8, 4],
+    [12, 4],
+    [225, 4],
+    [226, 4],
+    [227, 2],
+    [228, 2],
+    [1, 4],
+  ]
+  const tplSetLen = 4 + 4 + fieldSpecs.length * 4
+  const tpl = Buffer.alloc(16 + tplSetLen)
+  tpl.writeUInt16BE(10, 0)
+  tpl.writeUInt16BE(tpl.length, 2)
+  tpl.writeUInt16BE(2, 16)
+  tpl.writeUInt16BE(tplSetLen, 18)
+  tpl.writeUInt16BE(256, 20)
+  tpl.writeUInt16BE(fieldSpecs.length, 22)
+  let off = 24
+  for (const [type, len] of fieldSpecs) {
+    tpl.writeUInt16BE(type, off)
+    tpl.writeUInt16BE(len, off + 2)
+    off += 4
+  }
+  const recLen = fieldSpecs.reduce((n, [, len]) => n + len, 0)
+  const data = Buffer.alloc(16 + 4 + recLen)
+  data.writeUInt16BE(10, 0)
+  data.writeUInt16BE(data.length, 2)
+  data.writeUInt16BE(256, 16)
+  data.writeUInt16BE(4 + recLen, 18)
+  let d = 20
+  data[d] = 10; data[d + 1] = 200; data[d + 2] = 100; data[d + 3] = 53; d += 4
+  data[d] = 10; data[d + 1] = 200; data[d + 2] = 100; data[d + 3] = 1; d += 4
+  data[d] = 0; data[d + 1] = 0; data[d + 2] = 0; data[d + 3] = 0; d += 4
+  data[d] = 8; data[d + 1] = 8; data[d + 2] = 8; data[d + 3] = 8; d += 4
+  data.writeUInt16BE(53880, d); d += 2
+  data.writeUInt16BE(443, d); d += 2
+  data.writeUInt32BE(900, d)
+  parseFlowPacket(tpl, "10.255.254.9")
+  const nat = parseFlowPacket(data, "10.255.254.9")
+  assert.equal(nat.length, 1)
+  assert.equal(nat[0]?.src, "10.200.100.53")
+  assert.equal(nat[0]?.dst, "10.200.100.1")
+  assert.equal(nat[0]?.natSrc, "0.0.0.0")
+  assert.equal(nat[0]?.natDst, "8.8.8.8")
+  assert.equal(nat[0]?.natSrcPort, 53880)
+  assert.equal(nat[0]?.natDstPort, 443)
+  assert.equal(nat[0]?.bytes, 900)
+}
+
+resetFlowTemplatesForTests()
+{
+  const fieldSpecs: Array<[number, number]> = [
+    [225, 4],
+    [12, 4],
+    [1, 4],
+  ]
+  const tplSetLen = 4 + 4 + fieldSpecs.length * 4
+  const tpl = Buffer.alloc(16 + tplSetLen)
+  tpl.writeUInt16BE(10, 0)
+  tpl.writeUInt16BE(tpl.length, 2)
+  tpl.writeUInt16BE(2, 16)
+  tpl.writeUInt16BE(tplSetLen, 18)
+  tpl.writeUInt16BE(256, 20)
+  tpl.writeUInt16BE(fieldSpecs.length, 22)
+  let off = 24
+  for (const [type, len] of fieldSpecs) {
+    tpl.writeUInt16BE(type, off)
+    tpl.writeUInt16BE(len, off + 2)
+    off += 4
+  }
+  const recLen = fieldSpecs.reduce((n, [, len]) => n + len, 0)
+  const data = Buffer.alloc(16 + 4 + recLen)
+  data.writeUInt16BE(10, 0)
+  data.writeUInt16BE(data.length, 2)
+  data.writeUInt16BE(256, 16)
+  data.writeUInt16BE(4 + recLen, 18)
+  let d = 20
+  data[d] = 0; data[d + 1] = 0; data[d + 2] = 0; data[d + 3] = 0; d += 4
+  data[d] = 8; data[d + 1] = 8; data[d + 2] = 8; data[d + 3] = 8; d += 4
+  data.writeUInt32BE(10, d)
+  parseFlowPacket(tpl, "10.255.254.10")
+  const zeroNat = parseFlowPacket(data, "10.255.254.10")
+  assert.equal(zeroNat[0]?.src, "")
+  assert.equal(zeroNat[0]?.natSrc, "0.0.0.0")
+  assert.equal(zeroNat[0]?.dst, "8.8.8.8")
+}
+
 resetFlowTemplatesForTests()
 {
   const tpl = Buffer.alloc(16 + 16 + 20)