diff --git a/compat/Makefile b/compat/Makefile
index 83f439c..57db3ea 100644
--- a/compat/Makefile
+++ b/compat/Makefile
@@ -8,6 +8,7 @@ DISTFILES =	Makefile \
 		imsg-buffer.c \
 		imsg.c \
 		imsg.h \
+		memmem.c \
 		queue.h \
 		reallocarray.c \
 		recallocarray.c \
diff --git a/compat/memmem.c b/compat/memmem.c
new file mode 100644
index 0000000..9b11960
--- /dev/null
+++ b/compat/memmem.c
@@ -0,0 +1,183 @@
+/*	$OpenBSD: memmem.c,v 1.5 2020/04/16 12:39:28 claudio Exp $ */
+
+/*
+ * Copyright (c) 2005-2020 Rich Felker, et al.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+ * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#include <string.h>
+#include <stdint.h>
+
+static char *
+twobyte_memmem(const unsigned char *h, size_t k, const unsigned char *n)
+{
+	uint16_t nw = n[0]<<8 | n[1], hw = h[0]<<8 | h[1];
+	for (h+=2, k-=2; k; k--, hw = hw<<8 | *h++)
+		if (hw == nw) return (char *)h-2;
+	return hw == nw ? (char *)h-2 : 0;
+}
+
+static char *
+threebyte_memmem(const unsigned char *h, size_t k, const unsigned char *n)
+{
+	uint32_t nw = n[0]<<24 | n[1]<<16 | n[2]<<8;
+	uint32_t hw = h[0]<<24 | h[1]<<16 | h[2]<<8;
+	for (h+=3, k-=3; k; k--, hw = (hw|*h++)<<8)
+		if (hw == nw) return (char *)h-3;
+	return hw == nw ? (char *)h-3 : 0;
+}
+
+static char *
+fourbyte_memmem(const unsigned char *h, size_t k, const unsigned char *n)
+{
+	uint32_t nw = n[0]<<24 | n[1]<<16 | n[2]<<8 | n[3];
+	uint32_t hw = h[0]<<24 | h[1]<<16 | h[2]<<8 | h[3];
+	for (h+=4, k-=4; k; k--, hw = hw<<8 | *h++)
+		if (hw == nw) return (char *)h-4;
+	return hw == nw ? (char *)h-4 : 0;
+}
+
+#define MAX(a,b) ((a)>(b)?(a):(b))
+#define MIN(a,b) ((a)<(b)?(a):(b))
+
+#define BITOP(a,b,op) \
+ ((a)[(size_t)(b)/(8*sizeof *(a))] op (size_t)1<<((size_t)(b)%(8*sizeof *(a))))
+
+/*
+ * Maxime Crochemore and Dominique Perrin, Two-way string-matching,
+ * Journal of the ACM, 38(3):651-675, July 1991.
+ */
+static char *
+twoway_memmem(const unsigned char *h, const unsigned char *z,
+    const unsigned char *n, size_t l)
+{
+	size_t i, ip, jp, k, p, ms, p0, mem, mem0;
+	size_t byteset[32 / sizeof(size_t)] = { 0 };
+	size_t shift[256];
+
+	/* Computing length of needle and fill shift table */
+	for (i=0; i<l; i++)
+		BITOP(byteset, n[i], |=), shift[n[i]] = i+1;
+
+	/* Compute maximal suffix */
+	ip = -1; jp = 0; k = p = 1;
+	while (jp+k<l) {
+		if (n[ip+k] == n[jp+k]) {
+			if (k == p) {
+				jp += p;
+				k = 1;
+			} else k++;
+		} else if (n[ip+k] > n[jp+k]) {
+			jp += k;
+			k = 1;
+			p = jp - ip;
+		} else {
+			ip = jp++;
+			k = p = 1;
+		}
+	}
+	ms = ip;
+	p0 = p;
+
+	/* And with the opposite comparison */
+	ip = -1; jp = 0; k = p = 1;
+	while (jp+k<l) {
+		if (n[ip+k] == n[jp+k]) {
+			if (k == p) {
+				jp += p;
+				k = 1;
+			} else k++;
+		} else if (n[ip+k] < n[jp+k]) {
+			jp += k;
+			k = 1;
+			p = jp - ip;
+		} else {
+			ip = jp++;
+			k = p = 1;
+		}
+	}
+	if (ip+1 > ms+1) ms = ip;
+	else p = p0;
+
+	/* Periodic needle? */
+	if (memcmp(n, n+p, ms+1)) {
+		mem0 = 0;
+		p = MAX(ms, l-ms-1) + 1;
+	} else mem0 = l-p;
+	mem = 0;
+
+	/* Search loop */
+	for (;;) {
+		/* If remainder of haystack is shorter than needle, done */
+		if (z-h < l) return 0;
+
+		/* Check last byte first; advance by shift on mismatch */
+		if (BITOP(byteset, h[l-1], &)) {
+			k = l-shift[h[l-1]];
+			if (k) {
+				if (k < mem) k = mem;
+				h += k;
+				mem = 0;
+				continue;
+			}
+		} else {
+			h += l;
+			mem = 0;
+			continue;
+		}
+
+		/* Compare right half */
+		for (k=MAX(ms+1,mem); k<l && n[k] == h[k]; k++);
+		if (k < l) {
+			h += k-ms;
+			mem = 0;
+			continue;
+		}
+		/* Compare left half */
+		for (k=ms+1; k>mem && n[k-1] == h[k-1]; k--);
+		if (k <= mem) return (char *)h;
+		h += p;
+		mem = mem0;
+	}
+}
+
+void *
+memmem(const void *h0, size_t k, const void *n0, size_t l)
+{
+	const unsigned char *h = h0, *n = n0;
+
+	/* Return immediately on empty needle */
+	if (!l) return (void *)h;
+
+	/* Return immediately when needle is longer than haystack */
+	if (k<l) return 0;
+
+	/* Use faster algorithms for short needles */
+	h = memchr(h0, *n, k);
+	if (!h || l==1) return (void *)h;
+	k -= h - (const unsigned char *)h0;
+	if (k<l) return 0;
+	if (l==2) return twobyte_memmem(h, k, n);
+	if (l==3) return threebyte_memmem(h, k, n);
+	if (l==4) return fourbyte_memmem(h, k, n);
+
+	return twoway_memmem(h, h+k, n, l);
+}
diff --git a/configure b/configure
index 82c78f2..03aaad8 100755
--- a/configure
+++ b/configure
@@ -250,6 +250,7 @@ runtest landlock	LANDLOCK	|| true
 runtest libevent	LIBEVENT	|| true
 runtest libevent2	LIBEVENT2	|| true
 runtest libtls		LIBTLS		|| true
+runtest memmem		MEMMEM		"" -D_GNU_SOURCE || true
 runtest openssl		OPENSSL		|| true
 runtest pr_set_name	PR_SET_NAME	|| true
 runtest program_invocation_short_name PROGRAM_INVOCATION_SHORT_NAME "" -D_GNU_SOURCE || true
@@ -390,6 +391,10 @@ fi
 if [ ${HAVE_IMSG} -eq 0 ]; then
 	COBJS="${COBJS} compat/imsg.o compat/imsg-buffer.o"
 fi
+if [ ${HAVE_MEMMEM} -eq 0 ]; then
+	echo "extern void *memmem(const void *, size_t, const void *, size_t);"
+	COBJS="${COBJS} compat/memmem.o"
+fi
 if [ ${HAVE_REALLOCARRAY} -eq 0 ]; then
 	echo "extern	void	*reallocarray(void*, size_t, size_t);"
 	COBJS="${COBJS} compat/reallocarray.o"
diff --git a/have/Makefile b/have/Makefile
index cdd0fec..4ac7158 100644
--- a/have/Makefile
+++ b/have/Makefile
@@ -10,6 +10,7 @@ DISTFILES =	Makefile \
 		libevent.c \
 		libevent2.c \
 		libtls.c \
+		memmem.c \
 		noop.c \
 		openssl.c \
 		pr_set_name.c \
diff --git a/have/memmem.c b/have/memmem.c
new file mode 100644
index 0000000..1171eb4
--- /dev/null
+++ b/have/memmem.c
@@ -0,0 +1,27 @@
+/*
+ * Copyright (c) 2022 Omar Polo <op@omarpolo.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 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 <string.h>
+
+int
+main(void)
+{
+	char		big[33], little[2];
+
+	memset(big, 0, sizeof(big));
+	memset(little, 0, sizeof(little));
+	return (memmem(big, sizeof(big), little, sizeof(little)) == NULL);
+}