Style fixes in the external pref64 support.

- Address a code review comment to pass a variable by reference
  instead of by pointer.
- Add two missed EXCLUDES() thread-safety annotations.
- Make "dumpsys dnsresolver" report externally-set prefixes
  differently from discovered prefixes.

Bug: 156914456
Test: existing unit tests pass
Original-Change: https://android-review.googlesource.com/1316178
Merged-In: Ifcdb16cc66c9234a2bd5f8aac70be809fe0dd223
Change-Id: Ifcdb16cc66c9234a2bd5f8aac70be809fe0dd223

4 files changed, 9 insertions, 8 deletions

diff --git a/Dns64Configuration.cpp b/Dns64Configuration.cpp
index 5b3849bd..115fc510 100644
--- a/Dns64Configuration.cpp
+++ b/Dns64Configuration.cpp
@@ -139,7 +139,8 @@ void Dns64Configuration::dump(DumpWriter& dw, unsigned netId) {
     if (cfg.prefix64.length() == 0) {
         dw.println("%s: no prefix yet discovered", kLabel);
     } else {
-        dw.println("%s: discovered prefix %s", kLabel, cfg.prefix64.toString().c_str());
+        dw.println("%s: %s prefix %s", kLabel, cfg.isFromPrefixDiscovery() ? "discovered" : "set",
+                   cfg.prefix64.toString().c_str());
     }
 }
 
@@ -238,8 +239,8 @@ void Dns64Configuration::recordDns64Config(const Dns64Config& cfg) {
     reportNat64PrefixStatus(cfg.netId, PREFIX_ADDED, cfg.prefix64);
 }
 
-int Dns64Configuration::setPrefix64(unsigned netId, const IPPrefix* pfx) {
-    if (pfx->isUninitialized() || pfx->family() != AF_INET6 || pfx->length() != 96) {
+int Dns64Configuration::setPrefix64(unsigned netId, const IPPrefix& pfx) {
+    if (pfx.isUninitialized() || pfx.family() != AF_INET6 || pfx.length() != 96) {
         return -EINVAL;
     }
 
@@ -256,7 +257,7 @@ int Dns64Configuration::setPrefix64(unsigned netId, const IPPrefix* pfx) {
     }
 
     Dns64Config cfg(kNoDiscoveryId, netId);
-    cfg.prefix64 = *pfx;
+    cfg.prefix64 = pfx;
     mDns64Configs.emplace(std::make_pair(netId, cfg));
 
     return 0;
diff --git a/Dns64Configuration.h b/Dns64Configuration.h
index c06a6c1e..387de785 100644
--- a/Dns64Configuration.h
+++ b/Dns64Configuration.h
@@ -82,8 +82,8 @@ class Dns64Configuration {
     void stopPrefixDiscovery(unsigned netId);
     netdutils::IPPrefix getPrefix64(unsigned netId) const;
 
-    int setPrefix64(unsigned netId, const netdutils::IPPrefix* pfx);
-    int clearPrefix64(unsigned netId);
+    int setPrefix64(unsigned netId, const netdutils::IPPrefix& pfx) EXCLUDES(mMutex);
+    int clearPrefix64(unsigned netId) EXCLUDES(mMutex);
 
     void dump(netdutils::DumpWriter& dw, unsigned netId);
 
diff --git a/DnsResolverService.cpp b/DnsResolverService.cpp
index 6f633331..becda286 100644
--- a/DnsResolverService.cpp
+++ b/DnsResolverService.cpp
@@ -253,7 +253,7 @@ binder_status_t DnsResolverService::dump(int fd, const char** args, uint32_t num
         return statusFromErrcode(-EINVAL);
     }
 
-    return statusFromErrcode(gDnsResolv->resolverCtrl.setPrefix64(netId, &prefix));
+    return statusFromErrcode(gDnsResolv->resolverCtrl.setPrefix64(netId, prefix));
 }
 
 ::ndk::ScopedAStatus DnsResolverService::setLogSeverity(int32_t logSeverity) {
diff --git a/ResolverController.h b/ResolverController.h
index 06c0bbc0..e81e1edb 100644
--- a/ResolverController.h
+++ b/ResolverController.h
@@ -54,7 +54,7 @@ class ResolverController {
     void stopPrefix64Discovery(int32_t netId);
 
     // Set or clear a NAT64 prefix discovered by other sources (e.g., RA).
-    int setPrefix64(unsigned netId, const netdutils::IPPrefix* prefix) {
+    int setPrefix64(unsigned netId, const netdutils::IPPrefix& prefix) {
         return mDns64Configuration.setPrefix64(netId, prefix);
     }