diff --git a/common/route/awooter.cc b/common/route/awooter.cc
index f38144b0..d4882114 100644
--- a/common/route/awooter.cc
+++ b/common/route/awooter.cc
@@ -52,6 +52,13 @@ namespace {
     }
 }
 
+using DownhillIter = decltype(Context(ArchArgs()).getPipsDownhill(WireId()).begin());
+
+struct DownhillIterWrapper {
+    DownhillIter current;
+    DownhillIter end;
+};
+
 extern "C" {
     USING_NEXTPNR_NAMESPACE;
 
@@ -255,6 +262,18 @@ extern "C" {
     CellInfo* npnr_portref_cell(const PortRef *const port) { return port->cell; }
     Loc npnr_cellinfo_get_location(const CellInfo *const info) { return info->getLocation(); }
 
+    void npnr_inc_downhill_iter(DownhillIterWrapper *iter) {
+        ++iter->current;
+    }
+
+    uint64_t npnr_deref_downhill_iter(DownhillIterWrapper *iter) {
+        wrap(*iter->current);
+    }
+
+    bool npnr_is_downhill_iter_done(DownhillIterWrapper *iter) {
+        return !(iter->current != iter->end);
+    }
+
     extern bool npnr_router_awooter(Context *ctx);
 }
 
diff --git a/common/route/awooter/rust/src/npnr.rs b/common/route/awooter/rust/src/npnr.rs
index a255d652..30fd5d0f 100644
--- a/common/route/awooter/rust/src/npnr.rs
+++ b/common/route/awooter/rust/src/npnr.rs
@@ -1,5 +1,5 @@
 use core::slice;
-use std::{collections::HashMap, ffi::CStr, marker::PhantomData};
+use std::{collections::HashMap, ffi::CStr, marker::PhantomData, os::raw::c_void};
 
 use libc::c_char;
 
@@ -314,6 +314,10 @@ extern "C" {
 
     fn npnr_portref_cell(port: *const PortRef) -> *mut CellInfo;
     fn npnr_cellinfo_get_location(info: *const CellInfo) -> Loc;
+
+    fn npnr_inc_downhill_iter(iter: *mut RawDownhillIter);
+    fn npnr_deref_downhill_iter(iter: *mut RawDownhillIter) -> PipId;
+    fn npnr_is_downhill_iter_done(iter: *mut RawDownhillIter) -> bool;
 }
 
 /// Store for the nets of a context.
@@ -396,6 +400,29 @@ impl<'a> Iterator for NetSinkWireIter<'a> {
     }
 }
 
+#[repr(C)]
+struct RawDownhillIter {
+    content: [u8; 0],
+}
+
+struct DownhillPipsIter {
+    iter: *mut RawDownhillIter,
+}
+
+impl Iterator for DownhillPipsIter {
+    type Item = PipId;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        if unsafe { npnr_is_downhill_iter_done(self.iter) } {
+            None
+        } else {
+            let pip = unsafe { npnr_deref_downhill_iter(self.iter) };
+            unsafe { npnr_inc_downhill_iter(self.iter) };
+            Some(pip)
+        }
+    }
+}
+
 macro_rules! log_info {
     ($($t:tt)*) => {
         let s = std::ffi::CString::new(format!($($t)*)).unwrap();