Add getsockname() and getpeername() methods to AsyncIoStream.

c++/src/kj/async-io.c++

@@ -190,6 +190,18 @@ public:
     KJ_SYSCALL(::setsockopt(fd, level, option, value, length));
   }
 
+  void getsockname(struct sockaddr* addr, uint* length) override {
+    socklen_t socklen = *length;
+    KJ_SYSCALL(::getsockname(fd, addr, &socklen));
+    *length = socklen;
+  }
+
+  void getpeername(struct sockaddr* addr, uint* length) override {
+    socklen_t socklen = *length;
+    KJ_SYSCALL(::getpeername(fd, addr, &socklen));
+    *length = socklen;
+  }
+
   Promise<void> waitConnected() {
     // Wait until initial connection has completed. This actually just waits until it is writable.
 
@@ -1329,6 +1341,12 @@ void AsyncIoStream::getsockopt(int level, int option, void* value, uint* length)
 void AsyncIoStream::setsockopt(int level, int option, const void* value, uint length) {
   KJ_UNIMPLEMENTED("Not a socket.");
 }
+void AsyncIoStream::getsockname(struct sockaddr* addr, uint* length) {
+  KJ_UNIMPLEMENTED("Not a socket.");
+}
+void AsyncIoStream::getpeername(struct sockaddr* addr, uint* length) {
+  KJ_UNIMPLEMENTED("Not a socket.");
+}
 void ConnectionReceiver::getsockopt(int level, int option, void* value, uint* length) {
   KJ_UNIMPLEMENTED("Not a socket.");
 }

c++/src/kj/async-io.h

@@ -31,6 +31,8 @@
 #include "thread.h"
 #include "time.h"
 
+struct sockaddr;
+
 namespace kj {
 
 class UnixEventPort;
@@ -69,6 +71,16 @@ public:
   // Corresponds to getsockopt() and setsockopt() syscalls. Will throw an "unimplemented" exception
   // if the stream is not a socket or the option is not appropriate for the socket type. The
   // default implementations always throw "unimplemented".
+
+  virtual void getsockname(struct sockaddr* addr, uint* length);
+  virtual void getpeername(struct sockaddr* addr, uint* length);
+  // Corresponds to getsockname() and getpeername() syscalls. Will throw an "unimplemented"
+  // exception if the stream is not a socket. The default implementations always throw
+  // "unimplemented".
+  //
+  // Note that we don't provide methods that return NetworkAddress because it usually wouldn't
+  // be useful. You can't connect() to or listen() on these addresses, obviously, because they are
+  // ephemeral addresses for a single connection.
 };
 
 struct OneWayPipe {