From 153bf6d828b7477f2b4992292feeefc995d42020 Mon Sep 17 00:00:00 2001
From: Calvin Kim <calvin@calvinkim.info>
Date: Wed, 12 Nov 2025 15:00:23 +0100
Subject: [PATCH] btcutil: use anet instead of net for android builds

Golang's net package has been broken for android since android 11
and the node will not be able to call net.InterfaceAddr() without
root.

For android builds, we use anet so that the btcd node can be used
without root.
---
 btcutil/go.mod         |  1 +
 btcutil/go.sum         |  2 ++
 btcutil/net.go         |  4 ++--
 btcutil/net_android.go | 25 +++++++++++++++++++++++++
 4 files changed, 30 insertions(+), 2 deletions(-)
 create mode 100644 btcutil/net_android.go

diff --git a/btcutil/go.mod b/btcutil/go.mod
index 723a9c97..3b53da6c 100644
--- a/btcutil/go.mod
+++ b/btcutil/go.mod
@@ -9,6 +9,7 @@ require (
 	github.com/btcsuite/btcd/chaincfg/chainhash v1.1.0
 	github.com/davecgh/go-spew v1.1.1
 	github.com/decred/dcrd/dcrec/secp256k1/v4 v4.0.1
+	github.com/kcalvinalvin/anet v0.0.0-20251112173137-d8ddc1f6dbee
 	github.com/kkdai/bstream v0.0.0-20161212061736-f391b8402d23
 	github.com/stretchr/testify v1.8.4
 	golang.org/x/crypto v0.25.0
diff --git a/btcutil/go.sum b/btcutil/go.sum
index fa59c6a8..9a81f939 100644
--- a/btcutil/go.sum
+++ b/btcutil/go.sum
@@ -16,6 +16,8 @@ github.com/decred/dcrd/dcrec/secp256k1/v4 v4.0.1 h1:YLtO71vCjJRCBcrPMtQ9nqBsqpA1
 github.com/decred/dcrd/dcrec/secp256k1/v4 v4.0.1/go.mod h1:hyedUtir6IdtD/7lIxGeCxkaw7y45JueMRL4DIyJDKs=
 github.com/golang/snappy v0.0.4 h1:yAGX7huGHXlcLOEtBnF4w7FQwA26wojNCwOYAEhLjQM=
 github.com/golang/snappy v0.0.4/go.mod h1:/XxbfmMg8lxefKM7IXC3fBNl/7bRcc72aCRzEWrmP2Q=
+github.com/kcalvinalvin/anet v0.0.0-20251112173137-d8ddc1f6dbee h1:FPP9HDkBbPyniu+u7FHZg+kKFX1WW0gxOGteJ0h3AJk=
+github.com/kcalvinalvin/anet v0.0.0-20251112173137-d8ddc1f6dbee/go.mod h1:N6sz6HwJAenJ6d+/xmSl0ikfV05ZrVGmjt1ryy/WOtE=
 github.com/kkdai/bstream v0.0.0-20161212061736-f391b8402d23 h1:FOOIBWrEkLgmlgGfMuZT83xIwfPDxEI2OHu6xUmJMFE=
 github.com/kkdai/bstream v0.0.0-20161212061736-f391b8402d23/go.mod h1:J+Gs4SYgM6CZQHDETBtE9HaSEkGmuNXF86RwHhHUvq4=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
diff --git a/btcutil/net.go b/btcutil/net.go
index ec563862..491e47b5 100644
--- a/btcutil/net.go
+++ b/btcutil/net.go
@@ -2,8 +2,8 @@
 // Use of this source code is governed by an ISC
 // license that can be found in the LICENSE file.
 
-//go:build !appengine
-// +build !appengine
+//go:build !android && !appengine
+// +build !android,!appengine
 
 package btcutil
 
diff --git a/btcutil/net_android.go b/btcutil/net_android.go
new file mode 100644
index 00000000..ab99f50b
--- /dev/null
+++ b/btcutil/net_android.go
@@ -0,0 +1,25 @@
+// Copyright (c) 2025 The btcsuite developers
+// Use of this source code is governed by an ISC
+// license that can be found in the LICENSE file.
+
+//go:build android
+// +build android
+
+package btcutil
+
+import (
+	"net"
+
+	"github.com/kcalvinalvin/anet"
+)
+
+// InterfaceAddrs returns a list of the system's network interface addresses.
+// We specifically wrap anet.InterfaceAddrs as the net pakcage has been broken
+// since android 11.
+//
+// The relevant github issue link is:
+// https://github.com/golang/go/issues/40569.
+// When the issue is later resolved, we should remove it.
+func InterfaceAddrs() ([]net.Addr, error) {
+	return anet.InterfaceAddrs()
+}