From 9608fd5caefa97e8c224db3b10b1147e9fe3275f Mon Sep 17 00:00:00 2001
From: Richard Patel <ripatel@jumptrading.com>
Date: Mon, 24 Aug 2026 04:01:27 +0000
Subject: [PATCH] ci: check build with old kernel headers

---
 .github/workflows/old_kernel_headers.yml | 26 ++++++++++++++++++++++++
 src/waltz/xdp/fd_xsk.c                   |  6 +++---
 src/waltz/xdp/fd_xsk.h                   | 23 ++++++++++++++++++++-
 3 files changed, 51 insertions(+), 4 deletions(-)
 create mode 100644 .github/workflows/old_kernel_headers.yml

diff --git a/.github/workflows/old_kernel_headers.yml b/.github/workflows/old_kernel_headers.yml
new file mode 100644
index 00000000000..9f411d7f02b
--- /dev/null
+++ b/.github/workflows/old_kernel_headers.yml
@@ -0,0 +1,26 @@
+name: Old Kernel Headers
+on:
+  pull_request:
+concurrency:
+  group: old-kernel-headers_${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: true
+jobs:
+  check:
+    timeout-minutes: 5
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v7
+
+      - name: Install old kernel headers
+        run: |
+          tmp="$(mktemp -d)"
+          trap 'rm -rf "$tmp"' EXIT
+          curl -sSfL --retry 3 -o "$tmp/libc-dev.deb" \
+            "https://archive.debian.org/debian/pool/main/l/linux/linux-libc-dev_4.19.249-2_amd64.deb"
+          ( cd "$tmp" && ar x libc-dev.deb && tar -xf data.tar.* )
+          rm -rf kernel-headers && mkdir kernel-headers
+          mv "$tmp/usr/include" kernel-headers/include
+          mv kernel-headers/include/x86_64-linux-gnu/asm kernel-headers/include/asm
+
+      - name: make check
+        run: make check -j EXTRA_CPPFLAGS="-isystem $PWD/kernel-headers/include"
diff --git a/src/waltz/xdp/fd_xsk.c b/src/waltz/xdp/fd_xsk.c
index 144e2957c99..649f597ec0e 100644
--- a/src/waltz/xdp/fd_xsk.c
+++ b/src/waltz/xdp/fd_xsk.c
@@ -60,7 +60,7 @@ fd_xsk_mmap_ring( fd_xdp_ring_t * ring,
                   long            map_off,
                   ulong           elem_sz,
                   ulong           depth,
-                  struct xdp_ring_offset const * ring_offset ) {
+                  fd_xdp_ring_offset_t const * ring_offset ) {
   /* TODO what is ring_offset->desc ? */
 
   /* sanity check */
@@ -140,7 +140,7 @@ fd_xsk_fini( fd_xsk_t * xsk ) {
 
   if( FD_LIKELY( xsk->xsk_fd>=0 ) ) {
     /* Clear XSK descriptors */
-    fd_memset( &xsk->offsets, 0, sizeof(struct xdp_mmap_offsets) );
+    fd_memset( &xsk->offsets, 0, sizeof(fd_xdp_mmap_offsets_t) );
     /* Close XSK */
     close( xsk->xsk_fd );
     xsk->xsk_fd = -1;
@@ -191,7 +191,7 @@ fd_xsk_setup_umem( fd_xsk_t *              xsk,
 # undef FD_SET_XSK_RING_DEPTH
 
   /* Request ring offsets */
-  socklen_t offsets_sz = sizeof(struct xdp_mmap_offsets);
+  socklen_t offsets_sz = sizeof(fd_xdp_mmap_offsets_t);
   res = getsockopt( xsk->xsk_fd, SOL_XDP, XDP_MMAP_OFFSETS,
                     &xsk->offsets, &offsets_sz );
   if( FD_UNLIKELY( res!=0 ) ) {
diff --git a/src/waltz/xdp/fd_xsk.h b/src/waltz/xdp/fd_xsk.h
index feb75362135..ed5c2ac49aa 100644
--- a/src/waltz/xdp/fd_xsk.h
+++ b/src/waltz/xdp/fd_xsk.h
@@ -107,6 +107,27 @@
 
 #include "../../util/fd_util_base.h"
 
+#ifndef XDP_USE_NEED_WAKEUP
+#define XDP_USE_NEED_WAKEUP (1<<3)
+#endif
+
+#ifndef XDP_RING_NEED_WAKEUP
+#define XDP_RING_NEED_WAKEUP (1u<<0)
+#endif
+
+struct fd_xdp_ring_offset {
+  ulong producer;
+  ulong consumer;
+  ulong desc;
+  ulong flags;
+};
+typedef struct fd_xdp_ring_offset fd_xdp_ring_offset_t;
+
+struct fd_xdp_mmap_offsets {
+  fd_xdp_ring_offset_t rx, tx, fr, cr;
+};
+typedef struct fd_xdp_mmap_offsets fd_xdp_mmap_offsets_t;
+
 /* FD_XSK_UMEM_ALIGN: byte alignment of UMEM area within fd_xsk_t.
    This requirement is set by the kernel as of Linux 4.18. */
 #define FD_XSK_UMEM_ALIGN (4096UL)
@@ -242,7 +263,7 @@ struct fd_xsk {
 
   /* Kernel descriptor of XSK rings in local address space
      returned by getsockopt(SOL_XDP, XDP_MMAP_OFFSETS) */
-  struct xdp_mmap_offsets offsets;
+  fd_xdp_mmap_offsets_t offsets;
 
   /* AF_XDP socket file descriptor */
   int xsk_fd;