[ipsec-doze] Add fchown capabilities, and fw rules

Add some firewall rules to allow doze mode packets to be sent/received
on ESP & no-socket packets. No-socket packets are no security risk
because they are either forwarded, going to be forwarded, or will be
dropped at routing tables (unless they are ESP).

Bug: 62994731
Test: New tests added, run
Change-Id: I2d8704498b564403d94123e4938091dee8fb98c1
diff --git a/libnetdutils/include/netdutils/MockSyscalls.h b/libnetdutils/include/netdutils/MockSyscalls.h
index 149ba59..06ca859 100644
--- a/libnetdutils/include/netdutils/MockSyscalls.h
+++ b/libnetdutils/include/netdutils/MockSyscalls.h
@@ -37,6 +37,8 @@
                        StatusOr<UniqueFd>(const std::string& pathname, int flags, mode_t mode));
     MOCK_CONST_METHOD3(socket, StatusOr<UniqueFd>(int domain, int type, int protocol));
     MOCK_CONST_METHOD3(getsockname, Status(Fd sock, sockaddr* addr, socklen_t* addrlen));
+    MOCK_CONST_METHOD5(getsockopt, Status(Fd sock, int level, int optname, void* optval,
+                                          socklen_t *optlen));
     MOCK_CONST_METHOD5(setsockopt, Status(Fd sock, int level, int optname, const void* optval,
                                           socklen_t optlen));