From a9e53a4a84d8eda66d009255e6a6a9ccad387649 Mon Sep 17 00:00:00 2001
From: cheatfate <eugene.kabanov@status.im>
Date: Fri, 4 Oct 2024 03:18:30 +0300
Subject: [PATCH] Attempt to fix issue with AnyLocal addresses in
 last-seen-p2p-address field.

---
 beacon_chain/rpc/rest_node_api.nim | 78 +++++++++++++++++++++++++++---
 1 file changed, 72 insertions(+), 6 deletions(-)

diff --git a/beacon_chain/rpc/rest_node_api.nim b/beacon_chain/rpc/rest_node_api.nim
index b96e0724b..31e8e0b03 100644
--- a/beacon_chain/rpc/rest_node_api.nim
+++ b/beacon_chain/rpc/rest_node_api.nim
@@ -7,6 +7,7 @@
 {.push raises: [].}
 
 import
+  std/algorithm,
   stew/byteutils,
   chronicles,
   eth/p2p/discoveryv5/enr,
@@ -97,15 +98,80 @@ proc toString(direction: PeerType): string =
   of PeerType.Outgoing:
     "outbound"
 
+proc getProtocolArgument(ma: MultiAddress,
+                         codec: MultiCodec): MaResult[seq[byte]] =
+  var buffer: seq[byte]
+  for item in ma:
+    let
+      ritem = ? item
+      code = ? ritem.protoCode()
+    if code == codec:
+      let arg = ? ritem.protoAddress()
+      return ok(arg)
+  err("Multiaddress codec has not been found")
+
 proc getLastSeenAddress(node: BeaconNode, id: PeerId): string =
-  # TODO (cheatfate): We need to provide filter here, which will be able to
-  # filter such multiaddresses like `/ip4/0.0.0.0` or local addresses or
-  # addresses with peer ids.
-  let addrs = node.network.switch.peerStore[AddressBook][id]
-  if len(addrs) > 0:
-    $addrs[len(addrs) - 1]
+  # Because `last_seen_p2p_address` is single address but libp2p reports lot of
+  # addresses, we going to sort list of addresses before selecting one. Here
+  # sort order list:
+  # 1. Globally routable IPv6 address.
+  # 2. Globally routable IPv4 address.
+  # 3. Non IPv4/IPv6 multiaddress.
+  # 4. Site-local IPv6 address.
+  # 5. Site-local IPv4 address.
+  # 6. Link-local IPv6 address.
+  # 7. Link-local IPv4 address.
+  # 8. Loopback IPv6 address.
+  # 9. Loopback IPv4 address.
+  # 10. All other IPv6 address types.
+  # 11. All other IPv4 address types.
+  proc compare(
+      a, b: tuple[address: MultiAddress, position: int]
+  ): int {.closure.} = cmp(a.position, b.position)
+  let addresses = node.network.switch.peerStore[AddressBook][id]
+  var temp: seq[tuple[address: MultiAddress, position: int]]
+  for address in addresses:
+    let res =
+      if IP4.matchPartial(address):
+        let address4 = address.getProtocolArgument(multiCodec("ip4")).valueOr:
+          continue
+        var ta4 = TransportAddress(family: AddressFamily.IPv4)
+        ta4.address_v4[0 .. 3] = address4[0 .. 3]
+        if ta4.isLoopback():
+          (address, 9)
+        elif ta4.isLinkLocal():
+          (address, 7)
+        elif ta4.isSiteLocal():
+          (address, 5)
+        elif ta4.isGlobal():
+          (address, 2)
+        else:
+          (address, 11)
+      elif IP6.matchPartial(address):
+        let address6 = address.getProtocolArgument(multiCodec("ip4")).valueOr:
+          continue
+        var ta6 = TransportAddress(family: AddressFamily.IPv4)
+        ta6.address_v6[0 .. 15] = address6[0 .. 15]
+        if ta6.isLoopback():
+          (address, 8)
+        elif ta6.isLinkLocal():
+          (address, 6)
+        elif ta6.isSiteLocal():
+          (address, 4)
+        elif ta6.isGlobal():
+          (address, 1)
+        else:
+          (address, 10)
+      else:
+        (address, 3)
+    temp.add(res)
+
+  if len(temp) > 0:
+    sort(temp, compare, SortOrder.Ascending)
+    $temp[0].address
   else:
     ""
+
 proc getDiscoveryAddresses(node: BeaconNode): seq[string] =
   let
     typedRec = TypedRecord.fromRecord(node.network.enrRecord())