mblk leak replace_headers (#158)

oxidecomputer · May 28, 2022 · 1245055 · 1245055
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commit 1245055
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diff --git a/illumos-ddi-dki/src/lib.rs b/illumos-ddi-dki/src/lib.rs
@@ -434,6 +434,7 @@ extern "C" {
     pub fn ddi_soft_state_fini(state_p: *mut *mut c_void);
     pub fn ddi_soft_state_zalloc(state: *mut c_void, item: c_int) -> c_int;
 
+    pub fn freeb(mp: *mut mblk_t);
     pub fn freemsg(mp: *mut mblk_t);
 
     pub fn gethrtime() -> hrtime_t;

diff --git a/opte/src/engine/packet.rs b/opte/src/engine/packet.rs
@@ -1279,6 +1279,9 @@ impl Packet<Parsed> {
             self.state.body.pkt_offset -= seg.len;
             self.state.body.seg_index -= 1;
             seg.nullify_cont();
+            // This segment has become an orphan and therefore must be
+            // freed manually.
+            PacketSeg::free(seg);
         }
 
         assert_eq!(self.state.body.seg_index, 0);
@@ -1644,6 +1647,18 @@ pub struct PacketSeg {
 }
 
 impl PacketSeg {
+    fn free(self) {
+        cfg_if! {
+            if #[cfg(all(not(feature = "std"), not(test)))] {
+                // Safety: We know the mblk wrapped by PacketSeg is legit
+                // and came from the system's allocb(9F).
+                unsafe { ddi::freeb(self.unwrap()) };
+            } else {
+                mock_freeb(self.unwrap());
+            }
+        }
+    }
+
     fn link(&mut self, seg: &PacketSeg) {
         unsafe { (*self.mp).b_cont = seg.mp };
     }