diff --git a/compat.h b/compat.h
index cabdf3ad..0693cf06 100644
--- a/compat.h
+++ b/compat.h
@@ -334,6 +334,16 @@ char		*strndup(const char *, size_t);
 void		*memmem(const void *, size_t, const void *, size_t);
 #endif
 
+#ifndef HAVE_HTONLL
+/* htonll.c */
+uint64_t	 htonll(uint64_t);
+#endif
+
+#ifndef HAVE_NTOHLL
+/* ntohll.c */
+uint64_t	 ntohll(uint64_t);
+#endif
+
 #ifndef HAVE_GETPEEREID
 /* getpeereid.c */
 int		getpeereid(int, uid_t *, gid_t *);
diff --git a/compat/htonll.c b/compat/htonll.c
new file mode 100644
index 00000000..aef65983
--- /dev/null
+++ b/compat/htonll.c
@@ -0,0 +1,30 @@
+/*
+ * Copyright (c) 2024 Nicholas Marriott <nicholas.marriott@gmail.com>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER
+ * IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
+ * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/types.h>
+
+#include "compat.h"
+
+uint64_t
+htonll(uint64_t v)
+{
+    uint32_t b;
+    uint32_t t;
+
+    b = htonl (v & 0xffffffff);
+    t = htonl (v >> 32);
+    return ((uint64_t)b << 32 | t);
+}
diff --git a/compat/imsg-buffer.c b/compat/imsg-buffer.c
index ea236efd..9aed0ed3 100644
--- a/compat/imsg-buffer.c
+++ b/compat/imsg-buffer.c
@@ -20,6 +20,7 @@
 #include <sys/types.h>
 #include <sys/socket.h>
 #include <sys/uio.h>
+#include <arpa/inet.h>
 
 #include <limits.h>
 #include <errno.h>
@@ -31,11 +32,17 @@
 #include "compat.h"
 #include "imsg.h"
 
+#undef htobe16
 #define htobe16 htons
+#undef htobe32
 #define htobe32 htonl
+#undef htobe64
 #define htobe64 htonll
+#undef be16toh
 #define be16toh ntohs
+#undef be32toh
 #define be32toh ntohl
+#undef be64toh
 #define be64toh ntohll
 
 static int	ibuf_realloc(struct ibuf *, size_t);
diff --git a/compat/ntohll.c b/compat/ntohll.c
new file mode 100644
index 00000000..c2fe1bb7
--- /dev/null
+++ b/compat/ntohll.c
@@ -0,0 +1,30 @@
+/*
+ * Copyright (c) 2024 Nicholas Marriott <nicholas.marriott@gmail.com>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER
+ * IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
+ * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/types.h>
+
+#include "compat.h"
+
+uint64_t
+ntohll(uint64_t v)
+{
+    uint32_t b;
+    uint32_t t;
+
+    b = ntohl (v & 0xffffffff);
+    t = ntohl (v >> 32);
+    return ((uint64_t)b << 32 | t);
+}
diff --git a/configure.ac b/configure.ac
index 020f21e5..6699ae63 100644
--- a/configure.ac
+++ b/configure.ac
@@ -148,7 +148,7 @@ AC_CHECK_FUNCS([ \
 	prctl \
 	proc_pidinfo \
 	getpeerucred \
-	sysconf \
+	sysconf
 ])
 
 # Check for functions with a compatibility implementation.
@@ -165,7 +165,9 @@ AC_REPLACE_FUNCS([ \
 	getpeereid \
 	getline \
 	getprogname \
+	htonll \
 	memmem \
+	ntohll \
 	setenv \
 	setproctitle \
 	strcasestr \