Adding upstream version 5.6.0.upstream/5.6.0upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

41 files changed, 5520 insertions, 0 deletions

diff --git a/contrib/base32hex.c b/contrib/base32hex.c
new file mode 100644
index 0000000..b12718e
--- /dev/null
+++ b/contrib/base32hex.c
@@ -0,0 +1,277 @@
+/*  Copyright (C) CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+ *  SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+#include "base32hex.h"
+
+#include <stdlib.h>
+#include <stdint.h>
+
+/*! \brief Maximal length of binary input to Base32hex encoding. */
+#define MAX_BIN_DATA_LEN	((INT32_MAX / 8) * 5)
+
+/*! \brief Base32hex padding character. */
+static const uint8_t base32hex_pad = '=';
+/*! \brief Base32hex alphabet.  Beware: original code was upper-case. */
+static const uint8_t base32hex_enc[] = "0123456789abcdefghijklmnopqrstuv";
+
+/*! \brief Indicates bad Base32hex character. */
+#define KO	255
+/*! \brief Indicates Base32hex padding character. */
+#define PD	 32
+
+/*! \brief Transformation and validation table for decoding Base32hex. */
+static const uint8_t base32hex_dec[256] = {
+	[  0] = KO, [ 43] = KO, ['V'] = 31, [129] = KO, [172] = KO, [215] = KO,
+	[  1] = KO, [ 44] = KO, ['W'] = KO, [130] = KO, [173] = KO, [216] = KO,
+	[  2] = KO, [ 45] = KO, ['X'] = KO, [131] = KO, [174] = KO, [217] = KO,
+	[  3] = KO, [ 46] = KO, ['Y'] = KO, [132] = KO, [175] = KO, [218] = KO,
+	[  4] = KO, [ 47] = KO, ['Z'] = KO, [133] = KO, [176] = KO, [219] = KO,
+	[  5] = KO, ['0'] =  0, [ 91] = KO, [134] = KO, [177] = KO, [220] = KO,
+	[  6] = KO, ['1'] =  1, [ 92] = KO, [135] = KO, [178] = KO, [221] = KO,
+	[  7] = KO, ['2'] =  2, [ 93] = KO, [136] = KO, [179] = KO, [222] = KO,
+	[  8] = KO, ['3'] =  3, [ 94] = KO, [137] = KO, [180] = KO, [223] = KO,
+	[  9] = KO, ['4'] =  4, [ 95] = KO, [138] = KO, [181] = KO, [224] = KO,
+	[ 10] = KO, ['5'] =  5, [ 96] = KO, [139] = KO, [182] = KO, [225] = KO,
+	[ 11] = KO, ['6'] =  6, ['a'] = 10, [140] = KO, [183] = KO, [226] = KO,
+	[ 12] = KO, ['7'] =  7, ['b'] = 11, [141] = KO, [184] = KO, [227] = KO,
+	[ 13] = KO, ['8'] =  8, ['c'] = 12, [142] = KO, [185] = KO, [228] = KO,
+	[ 14] = KO, ['9'] =  9, ['d'] = 13, [143] = KO, [186] = KO, [229] = KO,
+	[ 15] = KO, [ 58] = KO, ['e'] = 14, [144] = KO, [187] = KO, [230] = KO,
+	[ 16] = KO, [ 59] = KO, ['f'] = 15, [145] = KO, [188] = KO, [231] = KO,
+	[ 17] = KO, [ 60] = KO, ['g'] = 16, [146] = KO, [189] = KO, [232] = KO,
+	[ 18] = KO, ['='] = PD, ['h'] = 17, [147] = KO, [190] = KO, [233] = KO,
+	[ 19] = KO, [ 62] = KO, ['i'] = 18, [148] = KO, [191] = KO, [234] = KO,
+	[ 20] = KO, [ 63] = KO, ['j'] = 19, [149] = KO, [192] = KO, [235] = KO,
+	[ 21] = KO, [ 64] = KO, ['k'] = 20, [150] = KO, [193] = KO, [236] = KO,
+	[ 22] = KO, ['A'] = 10, ['l'] = 21, [151] = KO, [194] = KO, [237] = KO,
+	[ 23] = KO, ['B'] = 11, ['m'] = 22, [152] = KO, [195] = KO, [238] = KO,
+	[ 24] = KO, ['C'] = 12, ['n'] = 23, [153] = KO, [196] = KO, [239] = KO,
+	[ 25] = KO, ['D'] = 13, ['o'] = 24, [154] = KO, [197] = KO, [240] = KO,
+	[ 26] = KO, ['E'] = 14, ['p'] = 25, [155] = KO, [198] = KO, [241] = KO,
+	[ 27] = KO, ['F'] = 15, ['q'] = 26, [156] = KO, [199] = KO, [242] = KO,
+	[ 28] = KO, ['G'] = 16, ['r'] = 27, [157] = KO, [200] = KO, [243] = KO,
+	[ 29] = KO, ['H'] = 17, ['s'] = 28, [158] = KO, [201] = KO, [244] = KO,
+	[ 30] = KO, ['I'] = 18, ['t'] = 29, [159] = KO, [202] = KO, [245] = KO,
+	[ 31] = KO, ['J'] = 19, ['u'] = 30, [160] = KO, [203] = KO, [246] = KO,
+	[ 32] = KO, ['K'] = 20, ['v'] = 31, [161] = KO, [204] = KO, [247] = KO,
+	[ 33] = KO, ['L'] = 21, ['w'] = KO, [162] = KO, [205] = KO, [248] = KO,
+	[ 34] = KO, ['M'] = 22, ['x'] = KO, [163] = KO, [206] = KO, [249] = KO,
+	[ 35] = KO, ['N'] = 23, ['y'] = KO, [164] = KO, [207] = KO, [250] = KO,
+	[ 36] = KO, ['O'] = 24, ['z'] = KO, [165] = KO, [208] = KO, [251] = KO,
+	[ 37] = KO, ['P'] = 25, [123] = KO, [166] = KO, [209] = KO, [252] = KO,
+	[ 38] = KO, ['Q'] = 26, [124] = KO, [167] = KO, [210] = KO, [253] = KO,
+	[ 39] = KO, ['R'] = 27, [125] = KO, [168] = KO, [211] = KO, [254] = KO,
+	[ 40] = KO, ['S'] = 28, [126] = KO, [169] = KO, [212] = KO, [255] = KO,
+	[ 41] = KO, ['T'] = 29, [127] = KO, [170] = KO, [213] = KO,
+	[ 42] = KO, ['U'] = 30, [128] = KO, [171] = KO, [214] = KO,
+};
+
+int32_t base32hex_decode(const uint8_t  *in,
+                         const uint32_t in_len,
+                         uint8_t        *out,
+                         const uint32_t out_len)
+{
+	// Checking inputs.
+	if (in == NULL || out == NULL) {
+		return -1;
+	}
+	if (in_len > INT32_MAX || out_len < ((in_len + 7) / 8) * 5) {
+		return -1;
+	}
+	if ((in_len % 8) != 0) {
+		return -1;
+	}
+
+	const uint8_t	*stop = in + in_len;
+	uint8_t		*bin = out;
+	uint8_t		pad_len = 0;
+	uint8_t		c1, c2, c3, c4, c5, c6, c7, c8;
+
+	// Decoding loop takes 8 characters and creates 5 bytes.
+	while (in < stop) {
+		// Filling and transforming 8 Base32hex chars.
+		c1 = base32hex_dec[in[0]];
+		c2 = base32hex_dec[in[1]];
+		c3 = base32hex_dec[in[2]];
+		c4 = base32hex_dec[in[3]];
+		c5 = base32hex_dec[in[4]];
+		c6 = base32hex_dec[in[5]];
+		c7 = base32hex_dec[in[6]];
+		c8 = base32hex_dec[in[7]];
+
+		// Check 8. char if is bad or padding.
+		if (c8 >= PD) {
+			if (c8 == PD && pad_len == 0) {
+				pad_len = 1;
+			} else {
+				return -1;
+			}
+		}
+
+		// Check 7. char if is bad or padding (if so, 6. must be too).
+		if (c7 >= PD) {
+			if (c7 == PD && c6 == PD && pad_len == 1) {
+				pad_len = 3;
+			} else {
+				return -1;
+			}
+		}
+
+		// Check 6. char if is bad or padding.
+		if (c6 >= PD) {
+			if (!(c6 == PD && pad_len == 3)) {
+				return -1;
+			}
+		}
+
+		// Check 5. char if is bad or padding.
+		if (c5 >= PD) {
+			if (c5 == PD && pad_len == 3) {
+				pad_len = 4;
+			} else {
+				return -1;
+			}
+		}
+
+		// Check 4. char if is bad or padding (if so, 3. must be too).
+		if (c4 >= PD) {
+			if (c4 == PD && c3 == PD && pad_len == 4) {
+				pad_len = 6;
+			} else {
+				return -1;
+			}
+		}
+
+		// Check 3. char if is bad or padding.
+		if (c3 >= PD) {
+			if (!(c3 == PD && pad_len == 6)) {
+				return -1;
+			}
+		}
+
+		// 1. and 2. chars must not be padding.
+		if (c2 >= PD || c1 >= PD) {
+			return -1;
+		}
+
+		// Computing of output data based on padding length.
+		switch (pad_len) {
+		case 0:
+			bin[4] = (c7 << 5) + c8;
+		case 1:
+			bin[3] = (c5 << 7) + (c6 << 2) + (c7 >> 3);
+		case 3:
+			bin[2] = (c4 << 4) + (c5 >> 1);
+		case 4:
+			bin[1] = (c2 << 6) + (c3 << 1) + (c4 >> 4);
+		case 6:
+			bin[0] = (c1 << 3) + (c2 >> 2);
+		}
+
+		// Update output end.
+		switch (pad_len) {
+		case 0:
+			bin += 5;
+			break;
+		case 1:
+			bin += 4;
+			break;
+		case 3:
+			bin += 3;
+			break;
+		case 4:
+			bin += 2;
+			break;
+		case 6:
+			bin += 1;
+			break;
+		}
+
+		in += 8;
+	}
+
+	return (bin - out);
+}
+
+int32_t base32hex_encode(const uint8_t  *in,
+                         const uint32_t in_len,
+                         uint8_t        *out,
+                         const uint32_t out_len)
+{
+	// Checking inputs.
+	if (in == NULL || out == NULL) {
+		return -1;
+	}
+	if (in_len > MAX_BIN_DATA_LEN || out_len < ((in_len + 4) / 5) * 8) {
+		return -1;
+	}
+
+	uint8_t		rest_len = in_len % 5;
+	const uint8_t	*stop = in + in_len - rest_len;
+	uint8_t		*text = out;
+
+	// Encoding loop takes 5 bytes and creates 8 characters.
+	while (in < stop) {
+		text[0] = base32hex_enc[in[0] >> 3];
+		text[1] = base32hex_enc[(in[0] & 0x07) << 2 | in[1] >> 6];
+		text[2] = base32hex_enc[(in[1] & 0x3E) >> 1];
+		text[3] = base32hex_enc[(in[1] & 0x01) << 4 | in[2] >> 4];
+		text[4] = base32hex_enc[(in[2] & 0x0F) << 1 | in[3] >> 7];
+		text[5] = base32hex_enc[(in[3] & 0x7C) >> 2];
+		text[6] = base32hex_enc[(in[3] & 0x03) << 3 | in[4] >> 5];
+		text[7] = base32hex_enc[in[4] & 0x1F];
+		text += 8;
+		in += 5;
+	}
+
+	// Processing of padding, if any.
+	switch (rest_len) {
+	case 4:
+		text[0] = base32hex_enc[in[0] >> 3];
+		text[1] = base32hex_enc[(in[0] & 0x07) << 2 | in[1] >> 6];
+		text[2] = base32hex_enc[(in[1] & 0x3E) >> 1];
+		text[3] = base32hex_enc[(in[1] & 0x01) << 4 | in[2] >> 4];
+		text[4] = base32hex_enc[(in[2] & 0x0F) << 1 | in[3] >> 7];
+		text[5] = base32hex_enc[(in[3] & 0x7C) >> 2];
+		text[6] = base32hex_enc[(in[3] & 0x03) << 3];
+		text[7] = base32hex_pad;
+		text += 8;
+		break;
+	case 3:
+		text[0] = base32hex_enc[in[0] >> 3];
+		text[1] = base32hex_enc[(in[0] & 0x07) << 2 | in[1] >> 6];
+		text[2] = base32hex_enc[(in[1] & 0x3E) >> 1];
+		text[3] = base32hex_enc[(in[1] & 0x01) << 4 | in[2] >> 4];
+		text[4] = base32hex_enc[(in[2] & 0x0F) << 1];
+		text[5] = base32hex_pad;
+		text[6] = base32hex_pad;
+		text[7] = base32hex_pad;
+		text += 8;
+		break;
+	case 2:
+		text[0] = base32hex_enc[in[0] >> 3];
+		text[1] = base32hex_enc[(in[0] & 0x07) << 2 | in[1] >> 6];
+		text[2] = base32hex_enc[(in[1] & 0x3E) >> 1];
+		text[3] = base32hex_enc[(in[1] & 0x01) << 4];
+		text[4] = base32hex_pad;
+		text[5] = base32hex_pad;
+		text[6] = base32hex_pad;
+		text[7] = base32hex_pad;
+		text += 8;
+		break;
+	case 1:
+		text[0] = base32hex_enc[in[0] >> 3];
+		text[1] = base32hex_enc[(in[0] & 0x07) << 2];
+		text[2] = base32hex_pad;
+		text[3] = base32hex_pad;
+		text[4] = base32hex_pad;
+		text[5] = base32hex_pad;
+		text[6] = base32hex_pad;
+		text[7] = base32hex_pad;
+		text += 8;
+		break;
+	}
+
+	return (text - out);
+}
diff --git a/contrib/base32hex.h b/contrib/base32hex.h
new file mode 100644
index 0000000..2416786
--- /dev/null
+++ b/contrib/base32hex.h
@@ -0,0 +1,60 @@
+/*  Copyright (C) CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+ *  SPDX-License-Identifier: GPL-3.0-or-later
+ */
+/*!
+ * \file
+ *
+ * \brief Base32hex implementation (RFC 4648).
+ *
+ * \note Input Base32hex string can contain a-v characters. These characters
+ *       are considered as A-V equivalent.
+ *
+ * \addtogroup contrib
+ * @{
+ */
+
+#pragma once
+
+#include <stdint.h>
+
+/*!
+ * \brief Decodes text data using Base32hex.
+ *
+ * \note Input data needn't be terminated with '\0'.
+ *
+ * \note Input data must be continuous Base32hex string!
+ *
+ * \param in		Input text data.
+ * \param in_len	Length of input string.
+ * \param out		Output data buffer.
+ * \param out_len	Size of output buffer.
+ *
+ * \retval >=0		length of output data.
+ * \retval KNOT_E*	if error.
+ */
+int32_t base32hex_decode(const uint8_t  *in,
+                         const uint32_t in_len,
+                         uint8_t        *out,
+                         const uint32_t out_len);
+
+
+/*!
+ * \brief Encodes binary data using Base32hex.  Lower case is used!
+ *
+ * \note Output data buffer contains Base32hex text string which isn't
+ *       terminated with '\0'!
+ *
+ * \param in		Input binary data.
+ * \param in_len	Length of input data.
+ * \param out		Output data buffer.
+ * \param out_len	Size of output buffer.
+ *
+ * \retval >=0		length of output string.
+ * \retval <0		if error.
+ */
+int32_t base32hex_encode(const uint8_t  *in,
+                         const uint32_t in_len,
+                         uint8_t        *out,
+                         const uint32_t out_len);
+
+/*! @} */
diff --git a/contrib/base32hex.spdx b/contrib/base32hex.spdx
new file mode 100644
index 0000000..7137645
--- /dev/null
+++ b/contrib/base32hex.spdx
@@ -0,0 +1,10 @@
+SPDXVersion: SPDX-2.1
+DataLicense: CC0-1.0
+SPDXID: SPDXRef-DOCUMENT
+DocumentName: knotdns-base32hex
+DocumentNamespace: http://spdx.org/spdxdocs/spdx-v2.1-4f29f08d-5fbf-4793-934c-9a6a2e6d5517
+
+PackageName: knotdns-base32hex
+PackageDownloadLocation: git+https://gitlab.nic.cz/knot/knot-dns.git@2b3c828a4cb8d9595318552483d4947345426c30#src/libknot/internal/base32hex.c
+PackageOriginator: Organization: Knot DNS contributors
+PackageLicenseDeclared: GPL-3.0-or-later
diff --git a/contrib/base64.c b/contrib/base64.c
new file mode 100644
index 0000000..e5c004e
--- /dev/null
+++ b/contrib/base64.c
@@ -0,0 +1,260 @@
+/*  Copyright (C) CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+ *  SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+#include "base64.h"
+#include "libknot/errcode.h"
+
+#include <stdlib.h>
+#include <stdint.h>
+
+/*! \brief Maximal length of binary input to Base64 encoding. */
+#define MAX_BIN_DATA_LEN	((INT32_MAX / 4) * 3)
+
+/*! \brief Base64 padding character. */
+static const uint8_t base64_pad = '=';
+/*! \brief Base64 alphabet. */
+static const uint8_t base64_enc[] =
+	"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+
+/*! \brief Indicates bad Base64 character. */
+#define KO	255
+/*! \brief Indicates Base64 padding character. */
+#define PD	 64
+
+/*! \brief Transformation and validation table for decoding Base64. */
+static const uint8_t base64_dec[256] = {
+	[  0] = KO, ['+'] = 62, ['V'] = 21, [129] = KO, [172] = KO, [215] = KO,
+	[  1] = KO, [ 44] = KO, ['W'] = 22, [130] = KO, [173] = KO, [216] = KO,
+	[  2] = KO, [ 45] = KO, ['X'] = 23, [131] = KO, [174] = KO, [217] = KO,
+	[  3] = KO, [ 46] = KO, ['Y'] = 24, [132] = KO, [175] = KO, [218] = KO,
+	[  4] = KO, ['/'] = 63, ['Z'] = 25, [133] = KO, [176] = KO, [219] = KO,
+	[  5] = KO, ['0'] = 52, [ 91] = KO, [134] = KO, [177] = KO, [220] = KO,
+	[  6] = KO, ['1'] = 53, [ 92] = KO, [135] = KO, [178] = KO, [221] = KO,
+	[  7] = KO, ['2'] = 54, [ 93] = KO, [136] = KO, [179] = KO, [222] = KO,
+	[  8] = KO, ['3'] = 55, [ 94] = KO, [137] = KO, [180] = KO, [223] = KO,
+	[  9] = KO, ['4'] = 56, [ 95] = KO, [138] = KO, [181] = KO, [224] = KO,
+	[ 10] = KO, ['5'] = 57, [ 96] = KO, [139] = KO, [182] = KO, [225] = KO,
+	[ 11] = KO, ['6'] = 58, ['a'] = 26, [140] = KO, [183] = KO, [226] = KO,
+	[ 12] = KO, ['7'] = 59, ['b'] = 27, [141] = KO, [184] = KO, [227] = KO,
+	[ 13] = KO, ['8'] = 60, ['c'] = 28, [142] = KO, [185] = KO, [228] = KO,
+	[ 14] = KO, ['9'] = 61, ['d'] = 29, [143] = KO, [186] = KO, [229] = KO,
+	[ 15] = KO, [ 58] = KO, ['e'] = 30, [144] = KO, [187] = KO, [230] = KO,
+	[ 16] = KO, [ 59] = KO, ['f'] = 31, [145] = KO, [188] = KO, [231] = KO,
+	[ 17] = KO, [ 60] = KO, ['g'] = 32, [146] = KO, [189] = KO, [232] = KO,
+	[ 18] = KO, ['='] = PD, ['h'] = 33, [147] = KO, [190] = KO, [233] = KO,
+	[ 19] = KO, [ 62] = KO, ['i'] = 34, [148] = KO, [191] = KO, [234] = KO,
+	[ 20] = KO, [ 63] = KO, ['j'] = 35, [149] = KO, [192] = KO, [235] = KO,
+	[ 21] = KO, [ 64] = KO, ['k'] = 36, [150] = KO, [193] = KO, [236] = KO,
+	[ 22] = KO, ['A'] =  0, ['l'] = 37, [151] = KO, [194] = KO, [237] = KO,
+	[ 23] = KO, ['B'] =  1, ['m'] = 38, [152] = KO, [195] = KO, [238] = KO,
+	[ 24] = KO, ['C'] =  2, ['n'] = 39, [153] = KO, [196] = KO, [239] = KO,
+	[ 25] = KO, ['D'] =  3, ['o'] = 40, [154] = KO, [197] = KO, [240] = KO,
+	[ 26] = KO, ['E'] =  4, ['p'] = 41, [155] = KO, [198] = KO, [241] = KO,
+	[ 27] = KO, ['F'] =  5, ['q'] = 42, [156] = KO, [199] = KO, [242] = KO,
+	[ 28] = KO, ['G'] =  6, ['r'] = 43, [157] = KO, [200] = KO, [243] = KO,
+	[ 29] = KO, ['H'] =  7, ['s'] = 44, [158] = KO, [201] = KO, [244] = KO,
+	[ 30] = KO, ['I'] =  8, ['t'] = 45, [159] = KO, [202] = KO, [245] = KO,
+	[ 31] = KO, ['J'] =  9, ['u'] = 46, [160] = KO, [203] = KO, [246] = KO,
+	[ 32] = KO, ['K'] = 10, ['v'] = 47, [161] = KO, [204] = KO, [247] = KO,
+	[ 33] = KO, ['L'] = 11, ['w'] = 48, [162] = KO, [205] = KO, [248] = KO,
+	[ 34] = KO, ['M'] = 12, ['x'] = 49, [163] = KO, [206] = KO, [249] = KO,
+	[ 35] = KO, ['N'] = 13, ['y'] = 50, [164] = KO, [207] = KO, [250] = KO,
+	[ 36] = KO, ['O'] = 14, ['z'] = 51, [165] = KO, [208] = KO, [251] = KO,
+	[ 37] = KO, ['P'] = 15, [123] = KO, [166] = KO, [209] = KO, [252] = KO,
+	[ 38] = KO, ['Q'] = 16, [124] = KO, [167] = KO, [210] = KO, [253] = KO,
+	[ 39] = KO, ['R'] = 17, [125] = KO, [168] = KO, [211] = KO, [254] = KO,
+	[ 40] = KO, ['S'] = 18, [126] = KO, [169] = KO, [212] = KO, [255] = KO,
+	[ 41] = KO, ['T'] = 19, [127] = KO, [170] = KO, [213] = KO,
+	[ 42] = KO, ['U'] = 20, [128] = KO, [171] = KO, [214] = KO,
+};
+
+int32_t kr_base64_encode(const uint8_t  *in,
+                      const uint32_t in_len,
+                      uint8_t        *out,
+                      const uint32_t out_len)
+{
+	// Checking inputs.
+	if (in == NULL || out == NULL) {
+		return KNOT_EINVAL;
+	}
+	if (in_len > MAX_BIN_DATA_LEN || out_len < ((in_len + 2) / 3) * 4) {
+		return KNOT_ERANGE;
+	}
+
+	uint8_t		rest_len = in_len % 3;
+	const uint8_t	*stop = in + in_len - rest_len;
+	uint8_t		*text = out;
+
+	// Encoding loop takes 3 bytes and creates 4 characters.
+	while (in < stop) {
+		text[0] = base64_enc[in[0] >> 2];
+		text[1] = base64_enc[(in[0] & 0x03) << 4 | in[1] >> 4];
+		text[2] = base64_enc[(in[1] & 0x0F) << 2 | in[2] >> 6];
+		text[3] = base64_enc[in[2] & 0x3F];
+		text += 4;
+		in += 3;
+	}
+
+	// Processing of padding, if any.
+	switch (rest_len) {
+	case 2:
+		text[0] = base64_enc[in[0] >> 2];
+		text[1] = base64_enc[(in[0] & 0x03) << 4 | in[1] >> 4];
+		text[2] = base64_enc[(in[1] & 0x0F) << 2];
+		text[3] = base64_pad;
+		text += 4;
+		break;
+	case 1:
+		text[0] = base64_enc[in[0] >> 2];
+		text[1] = base64_enc[(in[0] & 0x03) << 4];
+		text[2] = base64_pad;
+		text[3] = base64_pad;
+		text += 4;
+		break;
+	}
+
+	return (text - out);
+}
+
+int32_t kr_base64_encode_alloc(const uint8_t  *in,
+                            const uint32_t in_len,
+                            uint8_t        **out)
+{
+	// Checking inputs.
+	if (out == NULL) {
+		return KNOT_EINVAL;
+	}
+	if (in_len > MAX_BIN_DATA_LEN) {
+		return KNOT_ERANGE;
+	}
+
+	// Compute output buffer length.
+	uint32_t out_len = ((in_len + 2) / 3) * 4;
+
+	// Allocate output buffer.
+	*out = malloc(out_len);
+	if (*out == NULL) {
+		return KNOT_ENOMEM;
+	}
+
+	// Encode data.
+	int32_t ret = kr_base64_encode(in, in_len, *out, out_len);
+	if (ret < 0) {
+		free(*out);
+		*out = NULL;
+	}
+
+	return ret;
+}
+
+int32_t kr_base64_decode(const uint8_t  *in,
+                      const uint32_t in_len,
+                      uint8_t        *out,
+                      const uint32_t out_len)
+{
+	// Checking inputs.
+	if (in == NULL || out == NULL) {
+		return KNOT_EINVAL;
+	}
+	if (in_len > INT32_MAX || out_len < ((in_len + 3) / 4) * 3) {
+		return KNOT_ERANGE;
+	}
+	if ((in_len % 4) != 0) {
+		return KNOT_BASE64_ESIZE;
+	}
+
+	const uint8_t	*stop = in + in_len;
+	uint8_t		*bin = out;
+	uint8_t		pad_len = 0;
+	uint8_t		c1, c2, c3, c4;
+
+	// Decoding loop takes 4 characters and creates 3 bytes.
+	while (in < stop) {
+		// Filling and transforming 4 Base64 chars.
+		c1 = base64_dec[in[0]];
+		c2 = base64_dec[in[1]];
+		c3 = base64_dec[in[2]];
+		c4 = base64_dec[in[3]];
+
+		// Check 4. char if is bad or padding.
+		if (c4 >= PD) {
+			if (c4 == PD && pad_len == 0) {
+				pad_len = 1;
+			} else {
+				return KNOT_BASE64_ECHAR;
+			}
+		}
+
+		// Check 3. char if is bad or padding.
+		if (c3 >= PD) {
+			if (c3 == PD && pad_len == 1) {
+				pad_len = 2;
+			} else {
+				return KNOT_BASE64_ECHAR;
+			}
+		}
+
+		// Check 1. and 2. chars if are not padding.
+		if (c2 >= PD || c1 >= PD) {
+			return KNOT_BASE64_ECHAR;
+		}
+
+		// Computing of output data based on padding length.
+		switch (pad_len) {
+		case 0:
+			bin[2] = (c3 << 6) + c4;
+			// FALLTHROUGH
+		case 1:
+			bin[1] = (c2 << 4) + (c3 >> 2);
+			// FALLTHROUGH
+		case 2:
+			bin[0] = (c1 << 2) + (c2 >> 4);
+		}
+
+		// Update output end.
+		switch (pad_len) {
+		case 0:
+			bin += 3;
+			break;
+		case 1:
+			bin += 2;
+			break;
+		case 2:
+			bin += 1;
+			break;
+		}
+
+		in += 4;
+	}
+
+	return (bin - out);
+}
+
+int32_t kr_base64_decode_alloc(const uint8_t  *in,
+                            const uint32_t in_len,
+                            uint8_t        **out)
+{
+	// Checking inputs.
+	if (out == NULL) {
+		return KNOT_EINVAL;
+	}
+
+	// Compute output buffer length.
+	uint32_t out_len = ((in_len + 3) / 4) * 3;
+
+	// Allocate output buffer.
+	*out = malloc(out_len);
+	if (*out == NULL) {
+		return KNOT_ENOMEM;
+	}
+
+	// Decode data.
+	int32_t ret = kr_base64_decode(in, in_len, *out, out_len);
+	if (ret < 0) {
+		free(*out);
+		*out = NULL;
+	}
+
+	return ret;
+}
diff --git a/contrib/base64.h b/contrib/base64.h
new file mode 100644
index 0000000..153aa72
--- /dev/null
+++ b/contrib/base64.h
@@ -0,0 +1,95 @@
+/*  Copyright (C) CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+ *  SPDX-License-Identifier: GPL-3.0-or-later
+ */
+/*!
+ * \file
+ *
+ * \brief Base64 implementation (RFC 4648).
+ *
+ * \addtogroup contrib
+ * @{
+ */
+
+#pragma once
+
+#include <stdint.h>
+
+/*!
+ * \brief Encodes binary data using Base64.
+ *
+ * \note Output data buffer contains Base64 text string which isn't
+ *       terminated with '\0'!
+ *
+ * \param in		Input binary data.
+ * \param in_len	Length of input data.
+ * \param out		Output data buffer.
+ * \param out_len	Size of output buffer.
+ *
+ * \retval >=0		length of output string.
+ * \retval KNOT_E*	if error.
+ */
+int32_t kr_base64_encode(const uint8_t  *in,
+                      const uint32_t in_len,
+                      uint8_t        *out,
+                      const uint32_t out_len);
+
+/*!
+ * \brief Encodes binary data using Base64 and output stores to own buffer.
+ *
+ * \note Output data buffer contains Base64 text string which isn't
+ *       terminated with '\0'!
+ *
+ * \note Output buffer should be deallocated after use.
+ *
+ * \param in		Input binary data.
+ * \param in_len	Length of input data.
+ * \param out		Output data buffer.
+ *
+ * \retval >=0		length of output string.
+ * \retval KNOT_E*	if error.
+ */
+int32_t kr_base64_encode_alloc(const uint8_t  *in,
+                            const uint32_t in_len,
+                            uint8_t        **out);
+
+/*!
+ * \brief Decodes text data using Base64.
+ *
+ * \note Input data needn't be terminated with '\0'.
+ *
+ * \note Input data must be continuous Base64 string!
+ *
+ * \param in		Input text data.
+ * \param in_len	Length of input string.
+ * \param out		Output data buffer.
+ * \param out_len	Size of output buffer.
+ *
+ * \retval >=0		length of output data.
+ * \retval KNOT_E*	if error.
+ */
+int32_t kr_base64_decode(const uint8_t  *in,
+                      const uint32_t in_len,
+                      uint8_t        *out,
+                      const uint32_t out_len);
+
+/*!
+ * \brief Decodes text data using Base64 and output stores to own buffer.
+ *
+ * \note Input data needn't be terminated with '\0'.
+ *
+ * \note Input data must be continuous Base64 string!
+ *
+ * \note Output buffer should be deallocated after use.
+ *
+ * \param in		Input text data.
+ * \param in_len	Length of input string.
+ * \param out		Output data buffer.
+ *
+ * \retval >=0		length of output data.
+ * \retval KNOT_E*	if error.
+ */
+int32_t kr_base64_decode_alloc(const uint8_t  *in,
+                            const uint32_t in_len,
+                            uint8_t        **out);
+
+/*! @} */
diff --git a/contrib/base64.spdx b/contrib/base64.spdx
new file mode 100644
index 0000000..15ce10d
--- /dev/null
+++ b/contrib/base64.spdx
@@ -0,0 +1,10 @@
+SPDXVersion: SPDX-2.1
+DataLicense: CC0-1.0
+SPDXID: SPDXRef-DOCUMENT
+DocumentName: knotdns-base64
+DocumentNamespace: http://spdx.org/spdxdocs/spdx-v2.1-669dfa8c-3b50-425f-92fc-9b7ce18999f2
+
+PackageName: knotdns-base64
+PackageDownloadLocation: git+https://gitlab.nic.cz/knot/knot-dns.git@2b3c828a4cb8d9595318552483d4947345426c30#src/libknot/internal/base64.c
+PackageOriginator: Organization: Knot DNS contributors
+PackageLicenseDeclared: GPL-3.0-or-later
diff --git a/contrib/base64url.c b/contrib/base64url.c
new file mode 100644
index 0000000..b7c7d2b
--- /dev/null
+++ b/contrib/base64url.c
@@ -0,0 +1,287 @@
+/*  Copyright (C) CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include "contrib/base64url.h"
+#include "libknot/errcode.h"
+
+#include <stdlib.h>
+#include <stdint.h>
+#include <ctype.h>
+
+/*! \brief Maximal length of binary input to Base64url encoding. */
+#define MAX_BIN_DATA_LEN	((INT32_MAX / 4) * 3)
+
+/*! \brief Base64url padding character. */
+static const uint8_t base64url_pad = '\0';
+/*! \brief Base64 alphabet. */
+static const uint8_t base64url_enc[] =
+	"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";
+
+/*! \brief Indicates bad Base64 character. */
+#define KO	255
+/*! \brief Indicates Base64 padding character. */
+#define PD	 64
+
+/*! \brief Transformation and validation table for decoding Base64. */
+static const uint8_t base64url_dec[256] = {
+	[  0] = PD, [ 43] = KO, ['V'] = 21, [129] = KO, [172] = KO, [215] = KO,
+	[  1] = KO, [ 44] = KO, ['W'] = 22, [130] = KO, [173] = KO, [216] = KO,
+	[  2] = KO, ['-'] = 62, ['X'] = 23, [131] = KO, [174] = KO, [217] = KO,
+	[  3] = KO, [ 46] = KO, ['Y'] = 24, [132] = KO, [175] = KO, [218] = KO,
+	[  4] = KO, [ 47] = KO, ['Z'] = 25, [133] = KO, [176] = KO, [219] = KO,
+	[  5] = KO, ['0'] = 52, [ 91] = KO, [134] = KO, [177] = KO, [220] = KO,
+	[  6] = KO, ['1'] = 53, [ 92] = KO, [135] = KO, [178] = KO, [221] = KO,
+	[  7] = KO, ['2'] = 54, [ 93] = KO, [136] = KO, [179] = KO, [222] = KO,
+	[  8] = KO, ['3'] = 55, [ 94] = KO, [137] = KO, [180] = KO, [223] = KO,
+	[  9] = KO, ['4'] = 56, ['_'] = 63, [138] = KO, [181] = KO, [224] = KO,
+	[ 10] = KO, ['5'] = 57, [ 96] = KO, [139] = KO, [182] = KO, [225] = KO,
+	[ 11] = KO, ['6'] = 58, ['a'] = 26, [140] = KO, [183] = KO, [226] = KO,
+	[ 12] = KO, ['7'] = 59, ['b'] = 27, [141] = KO, [184] = KO, [227] = KO,
+	[ 13] = KO, ['8'] = 60, ['c'] = 28, [142] = KO, [185] = KO, [228] = KO,
+	[ 14] = KO, ['9'] = 61, ['d'] = 29, [143] = KO, [186] = KO, [229] = KO,
+	[ 15] = KO, [ 58] = KO, ['e'] = 30, [144] = KO, [187] = KO, [230] = KO,
+	[ 16] = KO, [ 59] = KO, ['f'] = 31, [145] = KO, [188] = KO, [231] = KO,
+	[ 17] = KO, [ 60] = KO, ['g'] = 32, [146] = KO, [189] = KO, [232] = KO,
+	[ 18] = KO, [ 61] = KO, ['h'] = 33, [147] = KO, [190] = KO, [233] = KO,
+	[ 19] = KO, [ 62] = KO, ['i'] = 34, [148] = KO, [191] = KO, [234] = KO,
+	[ 20] = KO, [ 63] = KO, ['j'] = 35, [149] = KO, [192] = KO, [235] = KO,
+	[ 21] = KO, [ 64] = KO, ['k'] = 36, [150] = KO, [193] = KO, [236] = KO,
+	[ 22] = KO, ['A'] =  0, ['l'] = 37, [151] = KO, [194] = KO, [237] = KO,
+	[ 23] = KO, ['B'] =  1, ['m'] = 38, [152] = KO, [195] = KO, [238] = KO,
+	[ 24] = KO, ['C'] =  2, ['n'] = 39, [153] = KO, [196] = KO, [239] = KO,
+	[ 25] = KO, ['D'] =  3, ['o'] = 40, [154] = KO, [197] = KO, [240] = KO,
+	[ 26] = KO, ['E'] =  4, ['p'] = 41, [155] = KO, [198] = KO, [241] = KO,
+	[ 27] = KO, ['F'] =  5, ['q'] = 42, [156] = KO, [199] = KO, [242] = KO,
+	[ 28] = KO, ['G'] =  6, ['r'] = 43, [157] = KO, [200] = KO, [243] = KO,
+	[ 29] = KO, ['H'] =  7, ['s'] = 44, [158] = KO, [201] = KO, [244] = KO,
+	[ 30] = KO, ['I'] =  8, ['t'] = 45, [159] = KO, [202] = KO, [245] = KO,
+	[ 31] = KO, ['J'] =  9, ['u'] = 46, [160] = KO, [203] = KO, [246] = KO,
+	[ 32] = KO, ['K'] = 10, ['v'] = 47, [161] = KO, [204] = KO, [247] = KO,
+	[ 33] = KO, ['L'] = 11, ['w'] = 48, [162] = KO, [205] = KO, [248] = KO,
+	[ 34] = KO, ['M'] = 12, ['x'] = 49, [163] = KO, [206] = KO, [249] = KO,
+	[ 35] = KO, ['N'] = 13, ['y'] = 50, [164] = KO, [207] = KO, [250] = KO,
+	[ 36] = KO, ['O'] = 14, ['z'] = 51, [165] = KO, [208] = KO, [251] = KO,
+	['%'] = KO, ['P'] = 15, [123] = KO, [166] = KO, [209] = KO, [252] = KO,
+	[ 38] = KO, ['Q'] = 16, [124] = KO, [167] = KO, [210] = KO, [253] = KO,
+	[ 39] = KO, ['R'] = 17, [125] = KO, [168] = KO, [211] = KO, [254] = KO,
+	[ 40] = KO, ['S'] = 18, [126] = KO, [169] = KO, [212] = KO, [255] = KO,
+	[ 41] = KO, ['T'] = 19, [127] = KO, [170] = KO, [213] = KO,
+	[ 42] = KO, ['U'] = 20, [128] = KO, [171] = KO, [214] = KO,
+};
+
+int32_t kr_base64url_encode(const uint8_t  *in,
+                      const uint32_t in_len,
+                      uint8_t        *out,
+                      const uint32_t out_len)
+{
+	// Checking inputs.
+	if (in == NULL || out == NULL) {
+		return KNOT_EINVAL;
+	}
+	if (in_len > MAX_BIN_DATA_LEN || out_len < ((in_len + 2) / 3) * 4) {
+		return KNOT_ERANGE;
+	}
+
+	uint8_t		rest_len = in_len % 3;
+	const uint8_t	*stop = in + in_len - rest_len;
+	uint8_t		*text = out;
+
+	// Encoding loop takes 3 bytes and creates 4 characters.
+	while (in < stop) {
+		text[0] = base64url_enc[in[0] >> 2];
+		text[1] = base64url_enc[(in[0] & 0x03) << 4 | in[1] >> 4];
+		text[2] = base64url_enc[(in[1] & 0x0F) << 2 | in[2] >> 6];
+		text[3] = base64url_enc[in[2] & 0x3F];
+		text += 4;
+		in += 3;
+	}
+
+	// Processing of padding, if any.
+	switch (rest_len) {
+	case 2:
+		text[0] = base64url_enc[in[0] >> 2];
+		text[1] = base64url_enc[(in[0] & 0x03) << 4 | in[1] >> 4];
+		text[2] = base64url_enc[(in[1] & 0x0F) << 2];
+		text[3] = base64url_pad;
+		text += 3;
+		break;
+	case 1:
+		text[0] = base64url_enc[in[0] >> 2];
+		text[1] = base64url_enc[(in[0] & 0x03) << 4];
+		text[2] = base64url_pad;
+		text[3] = base64url_pad;
+		text += 2;
+		break;
+	}
+	return (text - out);
+}
+
+int32_t kr_base64url_encode_alloc(const uint8_t  *in,
+                            const uint32_t in_len,
+                            uint8_t        **out)
+{
+	// Checking inputs.
+	if (out == NULL) {
+		return KNOT_EINVAL;
+	}
+	if (in_len > MAX_BIN_DATA_LEN) {
+		return KNOT_ERANGE;
+	}
+
+	// Compute output buffer length.
+	uint32_t out_len = ((in_len + 2) / 3) * 4;
+
+	// Allocate output buffer.
+	*out = malloc(out_len);
+	if (*out == NULL) {
+		return KNOT_ENOMEM;
+	}
+
+	// Encode data.
+	int32_t ret = kr_base64url_encode(in, in_len, *out, out_len);
+	if (ret < 0) {
+		free(*out);
+		*out = NULL;
+	}
+
+	return ret;
+}
+
+int32_t kr_base64url_decode(const uint8_t  *in,
+                      uint32_t in_len,
+                      uint8_t        *out,
+                      const uint32_t out_len)
+{
+	// Checking inputs.
+	if (in == NULL || out == NULL) {
+		return KNOT_EINVAL;
+	}
+
+	// cut up to two "%3d" from the end of input
+	int pad3d = 0;
+	const uint8_t *end = in + in_len;
+	char *perc3d = "d3%d3%", *stop3d = perc3d + 6;
+	while (end != in && perc3d != stop3d && tolower(*--end) == *perc3d) {
+		if (*perc3d++ == '%') {
+			in_len -= 3;
+			pad3d++;
+		}
+	}
+
+	if (in_len > INT32_MAX || out_len < ((in_len + 3) / 4) * 3) {
+		return KNOT_ERANGE;
+	}
+
+	const uint8_t	*stop = in + in_len;
+	uint8_t		*bin = out;
+	uint8_t		pad_len = 0;
+	uint8_t		c1, c2, c3, c4;
+
+	// Decoding loop takes 4 characters and creates 3 bytes.
+	while (in < stop) {
+		// Filling and transforming 4 Base64 chars.
+		c1 =                   base64url_dec[in[0]]     ;
+		c2 =                   base64url_dec[in[1]]     ;
+		c3 = (in + 2 < stop) ? base64url_dec[in[2]] : PD;
+		c4 = (in + 3 < stop) ? base64url_dec[in[3]] : PD;
+
+		// Check 1. and 2. chars if are not padding
+		if (c1 >= PD || c2 >= PD) {
+			return KNOT_BASE64_ECHAR;
+		}
+		// Check 3. char if is bad or padding.
+		else if (c3 >= PD) {
+			if (c3 == PD) {
+				pad_len = 2;
+			} else {
+				return KNOT_BASE64_ECHAR;
+			}
+		}
+		// Check 3. char if is bad or padding.
+		else if (c4 >= PD) {
+			if (c4 == PD) {
+				pad_len = 1;
+			} else {
+				return KNOT_BASE64_ECHAR;
+			}
+		}
+
+		if (pad_len > 0 && in <= stop - 4) {
+			return KNOT_BASE64_ECHAR;
+		}
+
+		// Computing of output data based on padding length.
+		switch (pad_len) {
+		case 0:
+			bin[2] = (c3 << 6) + c4;
+			// FALLTHROUGH
+		case 1:
+			bin[1] = (c2 << 4) + (c3 >> 2);
+			// FALLTHROUGH
+		case 2:
+			bin[0] = (c1 << 2) + (c2 >> 4);
+		}
+
+		// Update output end.
+		switch (pad_len) {
+		case 0:
+			bin += 3;
+			break;
+		case 1:
+			bin += 2;
+			goto end;
+		case 2:
+			bin += 1;
+			goto end;
+		}
+
+		in += 4;
+	}
+
+end:
+	if (pad3d > pad_len) {
+		return KNOT_BASE64_ECHAR;
+	}
+	return (bin - out);
+}
+
+int32_t kr_base64url_decode_alloc(const uint8_t  *in,
+                            const uint32_t in_len,
+                            uint8_t        **out)
+{
+	// Checking inputs.
+	if (out == NULL) {
+		return KNOT_EINVAL;
+	}
+
+	// Compute output buffer length.
+	uint32_t out_len = ((in_len + 3) / 4) * 3;
+
+	// Allocate output buffer.
+	*out = malloc(out_len);
+	if (*out == NULL) {
+		return KNOT_ENOMEM;
+	}
+
+	// Decode data.
+	int32_t ret = kr_base64url_decode(in, in_len, *out, out_len);
+	if (ret < 0) {
+		free(*out);
+		*out = NULL;
+	}
+
+	return ret;
+}
diff --git a/contrib/base64url.h b/contrib/base64url.h
new file mode 100644
index 0000000..ad7c6e9
--- /dev/null
+++ b/contrib/base64url.h
@@ -0,0 +1,103 @@
+/*  Copyright (C) CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+/*!
+ * \brief Base64url implementation (RFC 4648).
+ */
+
+#pragma once
+
+#include <stdint.h>
+
+/*!
+ * \brief Encodes binary data using Base64.
+ *
+ * \note Output data buffer contains Base64 text string which isn't
+ *       terminated with '\0'!
+ *
+ * \param in		Input binary data.
+ * \param in_len	Length of input data.
+ * \param out		Output data buffer.
+ * \param out_len	Size of output buffer.
+ *
+ * \retval >=0		length of output string.
+ * \retval KNOT_E*	if error.
+ */
+int32_t kr_base64url_encode(const uint8_t  *in,
+                      const uint32_t in_len,
+                      uint8_t        *out,
+                      const uint32_t out_len);
+
+/*!
+ * \brief Encodes binary data using Base64 and output stores to own buffer.
+ *
+ * \note Output data buffer contains Base64 text string which isn't
+ *       terminated with '\0'!
+ *
+ * \note Output buffer should be deallocated after use.
+ *
+ * \param in		Input binary data.
+ * \param in_len	Length of input data.
+ * \param out		Output data buffer.
+ *
+ * \retval >=0		length of output string.
+ * \retval KNOT_E*	if error.
+ */
+int32_t kr_base64url_encode_alloc(const uint8_t  *in,
+                            const uint32_t in_len,
+                            uint8_t        **out);
+
+/*!
+ * \brief Decodes text data using Base64.
+ *
+ * \note Input data needn't be terminated with '\0'.
+ *
+ * \note Input data must be continuous Base64 string!
+ *
+ * \param in		Input text data.
+ * \param in_len	Length of input string.
+ * \param out		Output data buffer.
+ * \param out_len	Size of output buffer.
+ *
+ * \retval >=0		length of output data.
+ * \retval KNOT_E*	if error.
+ */
+int32_t kr_base64url_decode(const uint8_t  *in,
+                      uint32_t       in_len,
+                      uint8_t        *out,
+                      const uint32_t out_len);
+
+/*!
+ * \brief Decodes text data using Base64 and output stores to own buffer.
+ *
+ * \note Input data needn't be terminated with '\0'.
+ *
+ * \note Input data must be continuous Base64 string!
+ *
+ * \note Output buffer should be deallocated after use.
+ *
+ * \param in		Input text data.
+ * \param in_len	Length of input string.
+ * \param out		Output data buffer.
+ *
+ * \retval >=0		length of output data.
+ * \retval KNOT_E*	if error.
+ */
+int32_t kr_base64url_decode_alloc(const uint8_t  *in,
+                            const uint32_t in_len,
+                            uint8_t        **out);
+
+/*! @} */
diff --git a/contrib/ccan/asprintf/LICENSE b/contrib/ccan/asprintf/LICENSE
new file mode 120000
index 0000000..2354d12
--- /dev/null
+++ b/contrib/ccan/asprintf/LICENSE
@@ -0,0 +1 @@
+../../licenses/BSD-MIT
\ No newline at end of file
diff --git a/contrib/ccan/asprintf/asprintf.c b/contrib/ccan/asprintf/asprintf.c
new file mode 100644
index 0000000..4077599
--- /dev/null
+++ b/contrib/ccan/asprintf/asprintf.c
@@ -0,0 +1,57 @@
+/* SPDX-License-Identifier: MIT
+ * Source: https://ccodearchive.net/info/asprintf.html */
+#include <ccan/asprintf/asprintf.h>
+#include <stdarg.h>
+#include <stdio.h>
+
+char *PRINTF_FMT(1, 2) afmt(const char *fmt, ...)
+{
+	va_list ap;
+	char *ptr;
+
+	va_start(ap, fmt);
+	/* The BSD version apparently sets ptr to NULL on fail.  GNU loses. */
+	if (vasprintf(&ptr, fmt, ap) < 0)
+		ptr = NULL;
+	va_end(ap);
+	return ptr;
+}
+
+#if !HAVE_ASPRINTF
+#include <stdarg.h>
+#include <stdlib.h>
+
+int vasprintf(char **strp, const char *fmt, va_list ap)
+{
+	int len;
+	va_list ap_copy;
+
+	/* We need to make a copy of ap, since it's a use-once. */
+	va_copy(ap_copy, ap);
+	len = vsnprintf(NULL, 0, fmt, ap_copy);
+	va_end(ap_copy);
+
+	/* Until version 2.0.6 glibc would return -1 on truncated output.
+	 * OTOH, they had asprintf. */
+	if (len < 0)
+		return -1;
+
+	*strp = malloc(len+1);
+	if (!*strp)
+		return -1;
+
+	return vsprintf(*strp, fmt, ap);
+}
+
+int asprintf(char **strp, const char *fmt, ...)
+{
+	va_list ap;
+	int len;
+
+	va_start(ap, fmt);
+	len = vasprintf(strp, fmt, ap);
+	va_end(ap);
+
+	return len;
+}
+#endif /* !HAVE_ASPRINTF */
diff --git a/contrib/ccan/asprintf/asprintf.h b/contrib/ccan/asprintf/asprintf.h
new file mode 100644
index 0000000..d4cc5ca
--- /dev/null
+++ b/contrib/ccan/asprintf/asprintf.h
@@ -0,0 +1,51 @@
+/* SPDX-License-Identifier: MIT
+ * Source: https://ccodearchive.net/info/asprintf.html */
+#ifndef CCAN_ASPRINTF_H
+#define CCAN_ASPRINTF_H
+#include "config.h"
+#include <ccan/compiler/compiler.h>
+
+/**
+ * afmt - allocate and populate a string with the given format.
+ * @fmt: printf-style format.
+ *
+ * This is a simplified asprintf interface.  Returns NULL on error.
+ */
+char *PRINTF_FMT(1, 2) afmt(const char *fmt, ...);
+
+#if HAVE_ASPRINTF
+#include <stdio.h>
+#else
+#include <stdarg.h>
+/**
+ * asprintf - printf to a dynamically-allocated string.
+ * @strp: pointer to the string to allocate.
+ * @fmt: printf-style format.
+ *
+ * Returns -1 (and leaves @strp undefined) on an error.  Otherwise returns
+ * number of bytes printed into @strp.
+ *
+ * Example:
+ *	static char *greeting(const char *name)
+ *	{
+ *		char *str;
+ *		int len = asprintf(&str, "Hello %s", name);
+ *		if (len < 0)
+ *			return NULL;
+ *		return str;
+ *	}
+ */
+int PRINTF_FMT(2, 3) asprintf(char **strp, const char *fmt, ...);
+
+/**
+ * vasprintf - vprintf to a dynamically-allocated string.
+ * @strp: pointer to the string to allocate.
+ * @fmt: printf-style format.
+ *
+ * Returns -1 (and leaves @strp undefined) on an error.  Otherwise returns
+ * number of bytes printed into @strp.
+ */
+int vasprintf(char **strp, const char *fmt, va_list ap);
+#endif
+
+#endif /* CCAN_ASPRINTF_H */
diff --git a/contrib/ccan/asprintf/asprintf.spdx b/contrib/ccan/asprintf/asprintf.spdx
new file mode 100644
index 0000000..175078a
--- /dev/null
+++ b/contrib/ccan/asprintf/asprintf.spdx
@@ -0,0 +1,10 @@
+SPDXVersion: SPDX-2.1
+DataLicense: CC0-1.0
+SPDXID: SPDXRef-DOCUMENT
+DocumentName: ccan-asprintf
+DocumentNamespace: http://spdx.org/spdxdocs/spdx-v2.1-40d4b71d-00e9-4e75-b6da-559203e6b815
+
+PackageName: asprintf
+PackageDownloadLocation: git+https://github.com/rustyrussell/ccan@fb1dfd092940905883ea6473162f5f6e36624da2#ccan/asprintf
+PackageOriginator: Person: Rusty Russell (rusty@rustcorp.com.au)
+PackageLicenseDeclared: MIT
diff --git a/contrib/ccan/compiler/LICENSE b/contrib/ccan/compiler/LICENSE
new file mode 120000
index 0000000..b7951da
--- /dev/null
+++ b/contrib/ccan/compiler/LICENSE
@@ -0,0 +1 @@
+../../licenses/CC0
\ No newline at end of file
diff --git a/contrib/ccan/compiler/compiler.h b/contrib/ccan/compiler/compiler.h
new file mode 100644
index 0000000..7c4f955
--- /dev/null
+++ b/contrib/ccan/compiler/compiler.h
@@ -0,0 +1,232 @@
+/* SPDX-License-Identifier: CC0-1.0
+ * Source: https://ccodearchive.net/info/compiler.html */
+#ifndef CCAN_COMPILER_H
+#define CCAN_COMPILER_H
+#include "config.h"
+
+#ifndef COLD
+#if HAVE_ATTRIBUTE_COLD
+/**
+ * COLD - a function is unlikely to be called.
+ *
+ * Used to mark an unlikely code path and optimize appropriately.
+ * It is usually used on logging or error routines.
+ *
+ * Example:
+ * static void COLD moan(const char *reason)
+ * {
+ *	fprintf(stderr, "Error: %s (%s)\n", reason, strerror(errno));
+ * }
+ */
+#define COLD __attribute__((__cold__))
+#else
+#define COLD
+#endif
+#endif
+
+#ifndef NORETURN
+#if HAVE_ATTRIBUTE_NORETURN
+/**
+ * NORETURN - a function does not return
+ *
+ * Used to mark a function which exits; useful for suppressing warnings.
+ *
+ * Example:
+ * static void NORETURN fail(const char *reason)
+ * {
+ *	fprintf(stderr, "Error: %s (%s)\n", reason, strerror(errno));
+ *	exit(1);
+ * }
+ */
+#define NORETURN __attribute__((__noreturn__))
+#else
+#define NORETURN
+#endif
+#endif
+
+#ifndef PRINTF_FMT
+#if HAVE_ATTRIBUTE_PRINTF
+/**
+ * PRINTF_FMT - a function takes printf-style arguments
+ * @nfmt: the 1-based number of the function's format argument.
+ * @narg: the 1-based number of the function's first variable argument.
+ *
+ * This allows the compiler to check your parameters as it does for printf().
+ *
+ * Example:
+ * void PRINTF_FMT(2,3) my_printf(const char *prefix, const char *fmt, ...);
+ */
+#define PRINTF_FMT(nfmt, narg) \
+	__attribute__((format(__printf__, nfmt, narg)))
+#else
+#define PRINTF_FMT(nfmt, narg)
+#endif
+#endif
+
+#ifndef CONST_FUNCTION
+#if HAVE_ATTRIBUTE_CONST
+/**
+ * CONST_FUNCTION - a function's return depends only on its argument
+ *
+ * This allows the compiler to assume that the function will return the exact
+ * same value for the exact same arguments.  This implies that the function
+ * must not use global variables, or dereference pointer arguments.
+ */
+#define CONST_FUNCTION __attribute__((__const__))
+#else
+#define CONST_FUNCTION
+#endif
+
+#ifndef PURE_FUNCTION
+#if HAVE_ATTRIBUTE_PURE
+/**
+ * PURE_FUNCTION - a function is pure
+ *
+ * A pure function is one that has no side effects other than it's return value
+ * and uses no inputs other than it's arguments and global variables.
+ */
+#define PURE_FUNCTION __attribute__((__pure__))
+#else
+#define PURE_FUNCTION
+#endif
+#endif
+#endif
+
+#if HAVE_ATTRIBUTE_UNUSED
+#ifndef UNNEEDED
+/**
+ * UNNEEDED - a variable/function may not be needed
+ *
+ * This suppresses warnings about unused variables or functions, but tells
+ * the compiler that if it is unused it need not emit it into the source code.
+ *
+ * Example:
+ * // With some preprocessor options, this is unnecessary.
+ * static UNNEEDED int counter;
+ *
+ * // With some preprocessor options, this is unnecessary.
+ * static UNNEEDED void add_to_counter(int add)
+ * {
+ *	counter += add;
+ * }
+ */
+#define UNNEEDED __attribute__((__unused__))
+#endif
+
+#ifndef NEEDED
+#if HAVE_ATTRIBUTE_USED
+/**
+ * NEEDED - a variable/function is needed
+ *
+ * This suppresses warnings about unused variables or functions, but tells
+ * the compiler that it must exist even if it (seems) unused.
+ *
+ * Example:
+ *	// Even if this is unused, these are vital for debugging.
+ *	static NEEDED int counter;
+ *	static NEEDED void dump_counter(void)
+ *	{
+ *		printf("Counter is %i\n", counter);
+ *	}
+ */
+#define NEEDED __attribute__((__used__))
+#else
+/* Before used, unused functions and vars were always emitted. */
+#define NEEDED __attribute__((__unused__))
+#endif
+#endif
+
+#ifndef UNUSED
+/**
+ * UNUSED - a parameter is unused
+ *
+ * Some compilers (eg. gcc with -W or -Wunused) warn about unused
+ * function parameters.  This suppresses such warnings and indicates
+ * to the reader that it's deliberate.
+ *
+ * Example:
+ *	// This is used as a callback, so needs to have this prototype.
+ *	static int some_callback(void *unused UNUSED)
+ *	{
+ *		return 0;
+ *	}
+ */
+#define UNUSED __attribute__((__unused__))
+#endif
+#else
+#ifndef UNNEEDED
+#define UNNEEDED
+#endif
+#ifndef NEEDED
+#define NEEDED
+#endif
+#ifndef UNUSED
+#define UNUSED
+#endif
+#endif
+
+#ifndef IS_COMPILE_CONSTANT
+#if HAVE_BUILTIN_CONSTANT_P
+/**
+ * IS_COMPILE_CONSTANT - does the compiler know the value of this expression?
+ * @expr: the expression to evaluate
+ *
+ * When an expression manipulation is complicated, it is usually better to
+ * implement it in a function.  However, if the expression being manipulated is
+ * known at compile time, it is better to have the compiler see the entire
+ * expression so it can simply substitute the result.
+ *
+ * This can be done using the IS_COMPILE_CONSTANT() macro.
+ *
+ * Example:
+ *	enum greek { ALPHA, BETA, GAMMA, DELTA, EPSILON };
+ *
+ *	// Out-of-line version.
+ *	const char *greek_name(enum greek greek);
+ *
+ *	// Inline version.
+ *	static inline const char *_greek_name(enum greek greek)
+ *	{
+ *		switch (greek) {
+ *		case ALPHA: return "alpha";
+ *		case BETA: return "beta";
+ *		case GAMMA: return "gamma";
+ *		case DELTA: return "delta";
+ *		case EPSILON: return "epsilon";
+ *		default: return "**INVALID**";
+ *		}
+ *	}
+ *
+ *	// Use inline if compiler knows answer.  Otherwise call function
+ *	// to avoid copies of the same code everywhere.
+ *	#define greek_name(g)						\
+ *		 (IS_COMPILE_CONSTANT(greek) ? _greek_name(g) : greek_name(g))
+ */
+#define IS_COMPILE_CONSTANT(expr) __builtin_constant_p(expr)
+#else
+/* If we don't know, assume it's not. */
+#define IS_COMPILE_CONSTANT(expr) 0
+#endif
+#endif
+
+#ifndef WARN_UNUSED_RESULT
+#if HAVE_WARN_UNUSED_RESULT
+/**
+ * WARN_UNUSED_RESULT - warn if a function return value is unused.
+ *
+ * Used to mark a function where it is extremely unlikely that the caller
+ * can ignore the result, eg realloc().
+ *
+ * Example:
+ * // buf param may be freed by this; need return value!
+ * static char *WARN_UNUSED_RESULT enlarge(char *buf, unsigned *size)
+ * {
+ *	return realloc(buf, (*size) *= 2);
+ * }
+ */
+#define WARN_UNUSED_RESULT __attribute__((__warn_unused_result__))
+#else
+#define WARN_UNUSED_RESULT
+#endif
+#endif
+#endif /* CCAN_COMPILER_H */
diff --git a/contrib/ccan/compiler/compiler.spdx b/contrib/ccan/compiler/compiler.spdx
new file mode 100644
index 0000000..45f19f4
--- /dev/null
+++ b/contrib/ccan/compiler/compiler.spdx
@@ -0,0 +1,10 @@
+SPDXVersion: SPDX-2.1
+DataLicense: CC0-1.0
+SPDXID: SPDXRef-DOCUMENT
+DocumentName: ccan-compiler
+DocumentNamespace: http://spdx.org/spdxdocs/spdx-v2.1-1569e849-880d-4ce7-ba3e-f4aaec8fce52
+
+PackageName: compiler
+PackageDownloadLocation: git+https://github.com/rustyrussell/ccan@23e96f89d54b8d5c4675284bbcd44fba68d8f826#ccan/compiler
+PackageOriginator: Person: Rusty Russell (rusty@rustcorp.com.au)
+PackageLicenseDeclared: CC0-1.0
diff --git a/contrib/ccan/json/LICENSE b/contrib/ccan/json/LICENSE
new file mode 120000
index 0000000..2354d12
--- /dev/null
+++ b/contrib/ccan/json/LICENSE
@@ -0,0 +1 @@
+../../licenses/BSD-MIT
\ No newline at end of file
diff --git a/contrib/ccan/json/json.c b/contrib/ccan/json/json.c
new file mode 100644
index 0000000..a86c4db
--- /dev/null
+++ b/contrib/ccan/json/json.c
@@ -0,0 +1,1362 @@
+/* SPDX-License-Identifier: MIT
+ * Source: https://ccodearchive.net/info/json.html
+ * Copyright (C) 2011 Joseph A. Adams (joeyadams3.14159@gmail.com) */
+
+#include "json.h"
+
+#include <assert.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define out_of_memory() do {                    \
+		fprintf(stderr, "Out of memory.\n");    \
+		exit(EXIT_FAILURE);                     \
+	} while (0)
+
+/* Sadly, strdup is not portable. */
+static char *json_strdup(const char *str)
+{
+	char *ret = (char*) malloc(strlen(str) + 1);
+	if (ret == NULL)
+		out_of_memory();
+	strcpy(ret, str);
+	return ret;
+}
+
+/* String buffer */
+
+typedef struct
+{
+	char *cur;
+	char *end;
+	char *start;
+} SB;
+
+static void sb_init(SB *sb)
+{
+	sb->start = (char*) malloc(17);
+	if (sb->start == NULL)
+		out_of_memory();
+	sb->cur = sb->start;
+	sb->end = sb->start + 16;
+}
+
+/* sb and need may be evaluated multiple times. */
+#define sb_need(sb, need) do {                  \
+		if ((sb)->end - (sb)->cur < (need))     \
+			sb_grow(sb, need);                  \
+	} while (0)
+
+static void sb_grow(SB *sb, int need)
+{
+	size_t length = sb->cur - sb->start;
+	size_t alloc = sb->end - sb->start;
+	
+	do {
+		alloc *= 2;
+	} while (alloc < length + need);
+	
+	sb->start = (char*) realloc(sb->start, alloc + 1);
+	if (sb->start == NULL)
+		out_of_memory();
+	sb->cur = sb->start + length;
+	sb->end = sb->start + alloc;
+}
+
+static void sb_put(SB *sb, const char *bytes, int count)
+{
+	sb_need(sb, count);
+	memcpy(sb->cur, bytes, count);
+	sb->cur += count;
+}
+
+#define sb_putc(sb, c) do {         \
+		if ((sb)->cur >= (sb)->end) \
+			sb_grow(sb, 1);         \
+		*(sb)->cur++ = (c);         \
+	} while (0)
+
+static void sb_puts(SB *sb, const char *str)
+{
+	sb_put(sb, str, strlen(str));
+}
+
+static char *sb_finish(SB *sb)
+{
+	*sb->cur = 0;
+	assert(sb->start <= sb->cur && strlen(sb->start) == (size_t)(sb->cur - sb->start));
+	return sb->start;
+}
+
+static void sb_free(SB *sb)
+{
+	free(sb->start);
+}
+
+/*
+ * Unicode helper functions
+ *
+ * These are taken from the ccan/charset module and customized a bit.
+ * Putting them here means the compiler can (choose to) inline them,
+ * and it keeps ccan/json from having a dependency.
+ */
+
+/*
+ * Type for Unicode codepoints.
+ * We need our own because wchar_t might be 16 bits.
+ */
+typedef uint32_t uchar_t;
+
+/*
+ * Validate a single UTF-8 character starting at @s.
+ * The string must be null-terminated.
+ *
+ * If it's valid, return its length (1 thru 4).
+ * If it's invalid or clipped, return 0.
+ *
+ * This function implements the syntax given in RFC3629, which is
+ * the same as that given in The Unicode Standard, Version 6.0.
+ *
+ * It has the following properties:
+ *
+ *  * All codepoints U+0000..U+10FFFF may be encoded,
+ *    except for U+D800..U+DFFF, which are reserved
+ *    for UTF-16 surrogate pair encoding.
+ *  * UTF-8 byte sequences longer than 4 bytes are not permitted,
+ *    as they exceed the range of Unicode.
+ *  * The sixty-six Unicode "non-characters" are permitted
+ *    (namely, U+FDD0..U+FDEF, U+xxFFFE, and U+xxFFFF).
+ */
+static int utf8_validate_cz(const char *s)
+{
+	unsigned char c = *s++;
+	
+	if (c <= 0x7F) {        /* 00..7F */
+		return 1;
+	} else if (c <= 0xC1) { /* 80..C1 */
+		/* Disallow overlong 2-byte sequence. */
+		return 0;
+	} else if (c <= 0xDF) { /* C2..DF */
+		/* Make sure subsequent byte is in the range 0x80..0xBF. */
+		if (((unsigned char)*s++ & 0xC0) != 0x80)
+			return 0;
+		
+		return 2;
+	} else if (c <= 0xEF) { /* E0..EF */
+		/* Disallow overlong 3-byte sequence. */
+		if (c == 0xE0 && (unsigned char)*s < 0xA0)
+			return 0;
+		
+		/* Disallow U+D800..U+DFFF. */
+		if (c == 0xED && (unsigned char)*s > 0x9F)
+			return 0;
+		
+		/* Make sure subsequent bytes are in the range 0x80..0xBF. */
+		if (((unsigned char)*s++ & 0xC0) != 0x80)
+			return 0;
+		if (((unsigned char)*s++ & 0xC0) != 0x80)
+			return 0;
+		
+		return 3;
+	} else if (c <= 0xF4) { /* F0..F4 */
+		/* Disallow overlong 4-byte sequence. */
+		if (c == 0xF0 && (unsigned char)*s < 0x90)
+			return 0;
+		
+		/* Disallow codepoints beyond U+10FFFF. */
+		if (c == 0xF4 && (unsigned char)*s > 0x8F)
+			return 0;
+		
+		/* Make sure subsequent bytes are in the range 0x80..0xBF. */
+		if (((unsigned char)*s++ & 0xC0) != 0x80)
+			return 0;
+		if (((unsigned char)*s++ & 0xC0) != 0x80)
+			return 0;
+		if (((unsigned char)*s++ & 0xC0) != 0x80)
+			return 0;
+		
+		return 4;
+	} else {                /* F5..FF */
+		return 0;
+	}
+}
+
+/* Validate a null-terminated UTF-8 string. */
+static bool utf8_validate(const char *s)
+{
+	int len;
+	
+	for (; *s != 0; s += len) {
+		len = utf8_validate_cz(s);
+		if (len == 0)
+			return false;
+	}
+	
+	return true;
+}
+
+/*
+ * Read a single UTF-8 character starting at @s,
+ * returning the length, in bytes, of the character read.
+ *
+ * This function assumes input is valid UTF-8,
+ * and that there are enough characters in front of @s.
+ */
+static int utf8_read_char(const char *s, uchar_t *out)
+{
+	const unsigned char *c = (const unsigned char*) s;
+	
+	assert(utf8_validate_cz(s));
+
+	if (c[0] <= 0x7F) {
+		/* 00..7F */
+		*out = c[0];
+		return 1;
+	} else if (c[0] <= 0xDF) {
+		/* C2..DF (unless input is invalid) */
+		*out = ((uchar_t)c[0] & 0x1F) << 6 |
+		       ((uchar_t)c[1] & 0x3F);
+		return 2;
+	} else if (c[0] <= 0xEF) {
+		/* E0..EF */
+		*out = ((uchar_t)c[0] &  0xF) << 12 |
+		       ((uchar_t)c[1] & 0x3F) << 6  |
+		       ((uchar_t)c[2] & 0x3F);
+		return 3;
+	} else {
+		/* F0..F4 (unless input is invalid) */
+		*out = ((uchar_t)c[0] &  0x7) << 18 |
+		       ((uchar_t)c[1] & 0x3F) << 12 |
+		       ((uchar_t)c[2] & 0x3F) << 6  |
+		       ((uchar_t)c[3] & 0x3F);
+		return 4;
+	}
+}
+
+/*
+ * Write a single UTF-8 character to @s,
+ * returning the length, in bytes, of the character written.
+ *
+ * @unicode must be U+0000..U+10FFFF, but not U+D800..U+DFFF.
+ *
+ * This function will write up to 4 bytes to @out.
+ */
+static int utf8_write_char(uchar_t unicode, char *out)
+{
+	unsigned char *o = (unsigned char*) out;
+	
+	assert(unicode <= 0x10FFFF && !(unicode >= 0xD800 && unicode <= 0xDFFF));
+
+	if (unicode <= 0x7F) {
+		/* U+0000..U+007F */
+		*o++ = unicode;
+		return 1;
+	} else if (unicode <= 0x7FF) {
+		/* U+0080..U+07FF */
+		*o++ = 0xC0 | unicode >> 6;
+		*o++ = 0x80 | (unicode & 0x3F);
+		return 2;
+	} else if (unicode <= 0xFFFF) {
+		/* U+0800..U+FFFF */
+		*o++ = 0xE0 | unicode >> 12;
+		*o++ = 0x80 | (unicode >> 6 & 0x3F);
+		*o++ = 0x80 | (unicode & 0x3F);
+		return 3;
+	} else {
+		/* U+10000..U+10FFFF */
+		*o++ = 0xF0 | unicode >> 18;
+		*o++ = 0x80 | (unicode >> 12 & 0x3F);
+		*o++ = 0x80 | (unicode >> 6 & 0x3F);
+		*o++ = 0x80 | (unicode & 0x3F);
+		return 4;
+	}
+}
+
+/*
+ * Compute the Unicode codepoint of a UTF-16 surrogate pair.
+ *
+ * @uc should be 0xD800..0xDBFF, and @lc should be 0xDC00..0xDFFF.
+ * If they aren't, this function returns false.
+ */
+static bool from_surrogate_pair(uint16_t uc, uint16_t lc, uchar_t *unicode)
+{
+	if (uc >= 0xD800 && uc <= 0xDBFF && lc >= 0xDC00 && lc <= 0xDFFF) {
+		*unicode = 0x10000 + ((((uchar_t)uc & 0x3FF) << 10) | (lc & 0x3FF));
+		return true;
+	} else {
+		return false;
+	}
+}
+
+/*
+ * Construct a UTF-16 surrogate pair given a Unicode codepoint.
+ *
+ * @unicode must be U+10000..U+10FFFF.
+ */
+static void to_surrogate_pair(uchar_t unicode, uint16_t *uc, uint16_t *lc)
+{
+	uchar_t n;
+	
+	assert(unicode >= 0x10000 && unicode <= 0x10FFFF);
+	
+	n = unicode - 0x10000;
+	*uc = ((n >> 10) & 0x3FF) | 0xD800;
+	*lc = (n & 0x3FF) | 0xDC00;
+}
+
+#define is_space(c) ((c) == '\t' || (c) == '\n' || (c) == '\r' || (c) == ' ')
+#define is_digit(c) ((c) >= '0' && (c) <= '9')
+
+static bool parse_value     (const char **sp, JsonNode        **out);
+static bool parse_string    (const char **sp, char            **out);
+static bool parse_number    (const char **sp, double           *out);
+static bool parse_array     (const char **sp, JsonNode        **out);
+static bool parse_object    (const char **sp, JsonNode        **out);
+static bool parse_hex16     (const char **sp, uint16_t         *out);
+
+static bool expect_literal  (const char **sp, const char *str);
+static void skip_space      (const char **sp);
+
+static void emit_value              (SB *out, const JsonNode *node);
+static void emit_value_indented     (SB *out, const JsonNode *node, const char *space, int indent_level);
+static void emit_string             (SB *out, const char *str);
+static void emit_number             (SB *out, double num);
+static void emit_array              (SB *out, const JsonNode *array);
+static void emit_array_indented     (SB *out, const JsonNode *array, const char *space, int indent_level);
+static void emit_object             (SB *out, const JsonNode *object);
+static void emit_object_indented    (SB *out, const JsonNode *object, const char *space, int indent_level);
+
+static int write_hex16(char *out, uint16_t val);
+
+static JsonNode *mknode(JsonTag tag);
+static void append_node(JsonNode *parent, JsonNode *child);
+static void prepend_node(JsonNode *parent, JsonNode *child);
+static void append_member(JsonNode *object, char *key, JsonNode *value);
+
+/* Assertion-friendly validity checks */
+static bool tag_is_valid(unsigned int tag);
+static bool number_is_valid(const char *num);
+
+JsonNode *json_decode(const char *json)
+{
+	const char *s = json;
+	JsonNode *ret;
+	
+	skip_space(&s);
+	if (!parse_value(&s, &ret))
+		return NULL;
+	
+	skip_space(&s);
+	if (*s != 0) {
+		json_delete(ret);
+		return NULL;
+	}
+	
+	return ret;
+}
+
+char *json_encode(const JsonNode *node)
+{
+	return json_stringify(node, NULL);
+}
+
+char *json_encode_string(const char *str)
+{
+	SB sb;
+	sb_init(&sb);
+	
+	emit_string(&sb, str);
+	
+	return sb_finish(&sb);
+}
+
+char *json_stringify(const JsonNode *node, const char *space)
+{
+	SB sb;
+	sb_init(&sb);
+	
+	if (space != NULL)
+		emit_value_indented(&sb, node, space, 0);
+	else
+		emit_value(&sb, node);
+	
+	return sb_finish(&sb);
+}
+
+void json_delete(JsonNode *node)
+{
+	if (node != NULL) {
+		json_remove_from_parent(node);
+		
+		switch (node->tag) {
+			case JSON_STRING:
+				free(node->string_);
+				break;
+			case JSON_ARRAY:
+			case JSON_OBJECT:
+			{
+				JsonNode *child, *next;
+				for (child = node->children.head; child != NULL; child = next) {
+					next = child->next;
+					json_delete(child);
+				}
+				break;
+			}
+			default:;
+		}
+		
+		free(node);
+	}
+}
+
+bool json_validate(const char *json)
+{
+	const char *s = json;
+	
+	skip_space(&s);
+	if (!parse_value(&s, NULL))
+		return false;
+	
+	skip_space(&s);
+	if (*s != 0)
+		return false;
+	
+	return true;
+}
+
+JsonNode *json_find_element(JsonNode *array, int index)
+{
+	JsonNode *element;
+	int i = 0;
+	
+	if (array == NULL || array->tag != JSON_ARRAY)
+		return NULL;
+	
+	json_foreach(element, array) {
+		if (i == index)
+			return element;
+		i++;
+	}
+	
+	return NULL;
+}
+
+JsonNode *json_find_member(JsonNode *object, const char *name)
+{
+	JsonNode *member;
+	
+	if (object == NULL || object->tag != JSON_OBJECT)
+		return NULL;
+	
+	json_foreach(member, object)
+		if (strcmp(member->key, name) == 0)
+			return member;
+	
+	return NULL;
+}
+
+JsonNode *json_first_child(const JsonNode *node)
+{
+	if (node != NULL && (node->tag == JSON_ARRAY || node->tag == JSON_OBJECT))
+		return node->children.head;
+	return NULL;
+}
+
+static JsonNode *mknode(JsonTag tag)
+{
+	JsonNode *ret = (JsonNode*) calloc(1, sizeof(JsonNode));
+	if (ret == NULL)
+		out_of_memory();
+	ret->tag = tag;
+	return ret;
+}
+
+JsonNode *json_mknull(void)
+{
+	return mknode(JSON_NULL);
+}
+
+JsonNode *json_mkbool(bool b)
+{
+	JsonNode *ret = mknode(JSON_BOOL);
+	ret->bool_ = b;
+	return ret;
+}
+
+static JsonNode *mkstring(char *s)
+{
+	JsonNode *ret = mknode(JSON_STRING);
+	ret->string_ = s;
+	return ret;
+}
+
+JsonNode *json_mkstring(const char *s)
+{
+	return mkstring(json_strdup(s));
+}
+
+JsonNode *json_mknumber(double n)
+{
+	JsonNode *node = mknode(JSON_NUMBER);
+	node->number_ = n;
+	return node;
+}
+
+JsonNode *json_mkarray(void)
+{
+	return mknode(JSON_ARRAY);
+}
+
+JsonNode *json_mkobject(void)
+{
+	return mknode(JSON_OBJECT);
+}
+
+static void append_node(JsonNode *parent, JsonNode *child)
+{
+	child->parent = parent;
+	child->prev = parent->children.tail;
+	child->next = NULL;
+	
+	if (parent->children.tail != NULL)
+		parent->children.tail->next = child;
+	else
+		parent->children.head = child;
+	parent->children.tail = child;
+}
+
+static void prepend_node(JsonNode *parent, JsonNode *child)
+{
+	child->parent = parent;
+	child->prev = NULL;
+	child->next = parent->children.head;
+	
+	if (parent->children.head != NULL)
+		parent->children.head->prev = child;
+	else
+		parent->children.tail = child;
+	parent->children.head = child;
+}
+
+static void append_member(JsonNode *object, char *key, JsonNode *value)
+{
+	value->key = key;
+	append_node(object, value);
+}
+
+void json_append_element(JsonNode *array, JsonNode *element)
+{
+	assert(array->tag == JSON_ARRAY);
+	assert(element->parent == NULL);
+	
+	append_node(array, element);
+}
+
+void json_prepend_element(JsonNode *array, JsonNode *element)
+{
+	assert(array->tag == JSON_ARRAY);
+	assert(element->parent == NULL);
+	
+	prepend_node(array, element);
+}
+
+void json_append_member(JsonNode *object, const char *key, JsonNode *value)
+{
+	assert(object->tag == JSON_OBJECT);
+	assert(value->parent == NULL);
+	
+	append_member(object, json_strdup(key), value);
+}
+
+void json_prepend_member(JsonNode *object, const char *key, JsonNode *value)
+{
+	assert(object->tag == JSON_OBJECT);
+	assert(value->parent == NULL);
+	
+	value->key = json_strdup(key);
+	prepend_node(object, value);
+}
+
+void json_remove_from_parent(JsonNode *node)
+{
+	JsonNode *parent = node->parent;
+	
+	if (parent != NULL) {
+		if (node->prev != NULL)
+			node->prev->next = node->next;
+		else
+			parent->children.head = node->next;
+		if (node->next != NULL)
+			node->next->prev = node->prev;
+		else
+			parent->children.tail = node->prev;
+		
+		free(node->key);
+		
+		node->parent = NULL;
+		node->prev = node->next = NULL;
+		node->key = NULL;
+	}
+}
+
+static bool parse_value(const char **sp, JsonNode **out)
+{
+	const char *s = *sp;
+	
+	switch (*s) {
+		case 'n':
+			if (expect_literal(&s, "null")) {
+				if (out)
+					*out = json_mknull();
+				*sp = s;
+				return true;
+			}
+			return false;
+		
+		case 'f':
+			if (expect_literal(&s, "false")) {
+				if (out)
+					*out = json_mkbool(false);
+				*sp = s;
+				return true;
+			}
+			return false;
+		
+		case 't':
+			if (expect_literal(&s, "true")) {
+				if (out)
+					*out = json_mkbool(true);
+				*sp = s;
+				return true;
+			}
+			return false;
+		
+		case '"': {
+			char *str;
+			if (parse_string(&s, out ? &str : NULL)) {
+				if (out)
+					*out = mkstring(str);
+				*sp = s;
+				return true;
+			}
+			return false;
+		}
+		
+		case '[':
+			if (parse_array(&s, out)) {
+				*sp = s;
+				return true;
+			}
+			return false;
+		
+		case '{':
+			if (parse_object(&s, out)) {
+				*sp = s;
+				return true;
+			}
+			return false;
+		
+		default: {
+			double num;
+			if (parse_number(&s, out ? &num : NULL)) {
+				if (out)
+					*out = json_mknumber(num);
+				*sp = s;
+				return true;
+			}
+			return false;
+		}
+	}
+}
+
+static bool parse_array(const char **sp, JsonNode **out)
+{
+	const char *s = *sp;
+	JsonNode *ret = out ? json_mkarray() : NULL;
+	JsonNode *element;
+	
+	if (*s++ != '[')
+		goto failure;
+	skip_space(&s);
+	
+	if (*s == ']') {
+		s++;
+		goto success;
+	}
+	
+	for (;;) {
+		if (!parse_value(&s, out ? &element : NULL))
+			goto failure;
+		skip_space(&s);
+		
+		if (out)
+			json_append_element(ret, element);
+		
+		if (*s == ']') {
+			s++;
+			goto success;
+		}
+		
+		if (*s++ != ',')
+			goto failure;
+		skip_space(&s);
+	}
+	
+success:
+	*sp = s;
+	if (out)
+		*out = ret;
+	return true;
+
+failure:
+	json_delete(ret);
+	return false;
+}
+
+static bool parse_object(const char **sp, JsonNode **out)
+{
+	const char *s = *sp;
+	JsonNode *ret = out ? json_mkobject() : NULL;
+	char *key;
+	JsonNode *value;
+	
+	if (*s++ != '{')
+		goto failure;
+	skip_space(&s);
+	
+	if (*s == '}') {
+		s++;
+		goto success;
+	}
+	
+	for (;;) {
+		if (!parse_string(&s, out ? &key : NULL))
+			goto failure;
+		skip_space(&s);
+		
+		if (*s++ != ':')
+			goto failure_free_key;
+		skip_space(&s);
+		
+		if (!parse_value(&s, out ? &value : NULL))
+			goto failure_free_key;
+		skip_space(&s);
+		
+		if (out)
+			append_member(ret, key, value);
+		
+		if (*s == '}') {
+			s++;
+			goto success;
+		}
+		
+		if (*s++ != ',')
+			goto failure;
+		skip_space(&s);
+	}
+	
+success:
+	*sp = s;
+	if (out)
+		*out = ret;
+	return true;
+
+failure_free_key:
+	if (out)
+		free(key);
+failure:
+	json_delete(ret);
+	return false;
+}
+
+bool parse_string(const char **sp, char **out)
+{
+	const char *s = *sp;
+	SB sb = { NULL, NULL, NULL };
+	char throwaway_buffer[4];
+		/* enough space for a UTF-8 character */
+	char *b;
+	
+	if (*s++ != '"')
+		return false;
+	
+	if (out) {
+		sb_init(&sb);
+		sb_need(&sb, 4);
+		b = sb.cur;
+	} else {
+		b = throwaway_buffer;
+	}
+	
+	while (*s != '"') {
+		unsigned char c = *s++;
+		
+		/* Parse next character, and write it to b. */
+		if (c == '\\') {
+			c = *s++;
+			switch (c) {
+				case '"':
+				case '\\':
+				case '/':
+					*b++ = c;
+					break;
+				case 'b':
+					*b++ = '\b';
+					break;
+				case 'f':
+					*b++ = '\f';
+					break;
+				case 'n':
+					*b++ = '\n';
+					break;
+				case 'r':
+					*b++ = '\r';
+					break;
+				case 't':
+					*b++ = '\t';
+					break;
+				case 'u':
+				{
+					uint16_t uc, lc;
+					uchar_t unicode;
+					
+					if (!parse_hex16(&s, &uc))
+						goto failed;
+					
+					if (uc >= 0xD800 && uc <= 0xDFFF) {
+						/* Handle UTF-16 surrogate pair. */
+						if (*s++ != '\\' || *s++ != 'u' || !parse_hex16(&s, &lc))
+							goto failed; /* Incomplete surrogate pair. */
+						if (!from_surrogate_pair(uc, lc, &unicode))
+							goto failed; /* Invalid surrogate pair. */
+					} else if (uc == 0) {
+						/* Disallow "\u0000". */
+						goto failed;
+					} else {
+						unicode = uc;
+					}
+					
+					b += utf8_write_char(unicode, b);
+					break;
+				}
+				default:
+					/* Invalid escape */
+					goto failed;
+			}
+		} else if (c <= 0x1F) {
+			/* Control characters are not allowed in string literals. */
+			goto failed;
+		} else {
+			/* Validate and echo a UTF-8 character. */
+			int len;
+			
+			s--;
+			len = utf8_validate_cz(s);
+			if (len == 0)
+				goto failed; /* Invalid UTF-8 character. */
+			
+			while (len--)
+				*b++ = *s++;
+		}
+		
+		/*
+		 * Update sb to know about the new bytes,
+		 * and set up b to write another character.
+		 */
+		if (out) {
+			sb.cur = b;
+			sb_need(&sb, 4);
+			b = sb.cur;
+		} else {
+			b = throwaway_buffer;
+		}
+	}
+	s++;
+	
+	if (out)
+		*out = sb_finish(&sb);
+	*sp = s;
+	return true;
+
+failed:
+	if (out)
+		sb_free(&sb);
+	return false;
+}
+
+/*
+ * The JSON spec says that a number shall follow this precise pattern
+ * (spaces and quotes added for readability):
+ *	 '-'? (0 | [1-9][0-9]*) ('.' [0-9]+)? ([Ee] [+-]? [0-9]+)?
+ *
+ * However, some JSON parsers are more liberal.  For instance, PHP accepts
+ * '.5' and '1.'.  JSON.parse accepts '+3'.
+ *
+ * This function takes the strict approach.
+ */
+bool parse_number(const char **sp, double *out)
+{
+	const char *s = *sp;
+
+	/* '-'? */
+	if (*s == '-')
+		s++;
+
+	/* (0 | [1-9][0-9]*) */
+	if (*s == '0') {
+		s++;
+	} else {
+		if (!is_digit(*s))
+			return false;
+		do {
+			s++;
+		} while (is_digit(*s));
+	}
+
+	/* ('.' [0-9]+)? */
+	if (*s == '.') {
+		s++;
+		if (!is_digit(*s))
+			return false;
+		do {
+			s++;
+		} while (is_digit(*s));
+	}
+
+	/* ([Ee] [+-]? [0-9]+)? */
+	if (*s == 'E' || *s == 'e') {
+		s++;
+		if (*s == '+' || *s == '-')
+			s++;
+		if (!is_digit(*s))
+			return false;
+		do {
+			s++;
+		} while (is_digit(*s));
+	}
+
+	if (out)
+		*out = strtod(*sp, NULL);
+
+	*sp = s;
+	return true;
+}
+
+static void skip_space(const char **sp)
+{
+	const char *s = *sp;
+	while (is_space(*s))
+		s++;
+	*sp = s;
+}
+
+static void emit_value(SB *out, const JsonNode *node)
+{
+	assert(tag_is_valid(node->tag));
+	switch (node->tag) {
+		case JSON_NULL:
+			sb_puts(out, "null");
+			break;
+		case JSON_BOOL:
+			sb_puts(out, node->bool_ ? "true" : "false");
+			break;
+		case JSON_STRING:
+			emit_string(out, node->string_);
+			break;
+		case JSON_NUMBER:
+			emit_number(out, node->number_);
+			break;
+		case JSON_ARRAY:
+			emit_array(out, node);
+			break;
+		case JSON_OBJECT:
+			emit_object(out, node);
+			break;
+		default:
+			assert(false);
+	}
+}
+
+void emit_value_indented(SB *out, const JsonNode *node, const char *space, int indent_level)
+{
+	assert(tag_is_valid(node->tag));
+	switch (node->tag) {
+		case JSON_NULL:
+			sb_puts(out, "null");
+			break;
+		case JSON_BOOL:
+			sb_puts(out, node->bool_ ? "true" : "false");
+			break;
+		case JSON_STRING:
+			emit_string(out, node->string_);
+			break;
+		case JSON_NUMBER:
+			emit_number(out, node->number_);
+			break;
+		case JSON_ARRAY:
+			emit_array_indented(out, node, space, indent_level);
+			break;
+		case JSON_OBJECT:
+			emit_object_indented(out, node, space, indent_level);
+			break;
+		default:
+			assert(false);
+	}
+}
+
+static void emit_array(SB *out, const JsonNode *array)
+{
+	const JsonNode *element;
+	
+	sb_putc(out, '[');
+	json_foreach(element, array) {
+		emit_value(out, element);
+		if (element->next != NULL)
+			sb_putc(out, ',');
+	}
+	sb_putc(out, ']');
+}
+
+static void emit_array_indented(SB *out, const JsonNode *array, const char *space, int indent_level)
+{
+	const JsonNode *element = array->children.head;
+	int i;
+	
+	if (element == NULL) {
+		sb_puts(out, "[]");
+		return;
+	}
+	
+	sb_puts(out, "[\n");
+	while (element != NULL) {
+		for (i = 0; i < indent_level + 1; i++)
+			sb_puts(out, space);
+		emit_value_indented(out, element, space, indent_level + 1);
+		
+		element = element->next;
+		sb_puts(out, element != NULL ? ",\n" : "\n");
+	}
+	for (i = 0; i < indent_level; i++)
+		sb_puts(out, space);
+	sb_putc(out, ']');
+}
+
+static void emit_object(SB *out, const JsonNode *object)
+{
+	const JsonNode *member;
+	
+	sb_putc(out, '{');
+	json_foreach(member, object) {
+		emit_string(out, member->key);
+		sb_putc(out, ':');
+		emit_value(out, member);
+		if (member->next != NULL)
+			sb_putc(out, ',');
+	}
+	sb_putc(out, '}');
+}
+
+static void emit_object_indented(SB *out, const JsonNode *object, const char *space, int indent_level)
+{
+	const JsonNode *member = object->children.head;
+	int i;
+	
+	if (member == NULL) {
+		sb_puts(out, "{}");
+		return;
+	}
+	
+	sb_puts(out, "{\n");
+	while (member != NULL) {
+		for (i = 0; i < indent_level + 1; i++)
+			sb_puts(out, space);
+		emit_string(out, member->key);
+		sb_puts(out, ": ");
+		emit_value_indented(out, member, space, indent_level + 1);
+		
+		member = member->next;
+		sb_puts(out, member != NULL ? ",\n" : "\n");
+	}
+	for (i = 0; i < indent_level; i++)
+		sb_puts(out, space);
+	sb_putc(out, '}');
+}
+
+void emit_string(SB *out, const char *str)
+{
+	bool escape_unicode = false;
+	const char *s = str;
+	char *b;
+	
+	assert(utf8_validate(str));
+	
+	/*
+	 * 14 bytes is enough space to write up to two
+	 * \uXXXX escapes and two quotation marks.
+	 */
+	sb_need(out, 14);
+	b = out->cur;
+	
+	*b++ = '"';
+	while (*s != 0) {
+		unsigned char c = *s++;
+		
+		/* Encode the next character, and write it to b. */
+		switch (c) {
+			case '"':
+				*b++ = '\\';
+				*b++ = '"';
+				break;
+			case '\\':
+				*b++ = '\\';
+				*b++ = '\\';
+				break;
+			case '\b':
+				*b++ = '\\';
+				*b++ = 'b';
+				break;
+			case '\f':
+				*b++ = '\\';
+				*b++ = 'f';
+				break;
+			case '\n':
+				*b++ = '\\';
+				*b++ = 'n';
+				break;
+			case '\r':
+				*b++ = '\\';
+				*b++ = 'r';
+				break;
+			case '\t':
+				*b++ = '\\';
+				*b++ = 't';
+				break;
+			default: {
+				int len;
+				
+				s--;
+				len = utf8_validate_cz(s);
+				
+				if (len == 0) {
+					/*
+					 * Handle invalid UTF-8 character gracefully in production
+					 * by writing a replacement character (U+FFFD)
+					 * and skipping a single byte.
+					 *
+					 * This should never happen when assertions are enabled
+					 * due to the assertion at the beginning of this function.
+					 */
+					assert(false);
+					if (escape_unicode) {
+						strcpy(b, "\\uFFFD");
+						b += 6;
+					} else {
+						*b++ = (char)0xEF;
+						*b++ = (char)0xBF;
+						*b++ = (char)0xBD;
+					}
+					s++;
+				} else if (c < 0x1F || (c >= 0x80 && escape_unicode)) {
+					/* Encode using \u.... */
+					uint32_t unicode;
+					
+					s += utf8_read_char(s, &unicode);
+					
+					if (unicode <= 0xFFFF) {
+						*b++ = '\\';
+						*b++ = 'u';
+						b += write_hex16(b, unicode);
+					} else {
+						/* Produce a surrogate pair. */
+						uint16_t uc, lc;
+						assert(unicode <= 0x10FFFF);
+						to_surrogate_pair(unicode, &uc, &lc);
+						*b++ = '\\';
+						*b++ = 'u';
+						b += write_hex16(b, uc);
+						*b++ = '\\';
+						*b++ = 'u';
+						b += write_hex16(b, lc);
+					}
+				} else {
+					/* Write the character directly. */
+					while (len--)
+						*b++ = *s++;
+				}
+				
+				break;
+			}
+		}
+	
+		/*
+		 * Update *out to know about the new bytes,
+		 * and set up b to write another encoded character.
+		 */
+		out->cur = b;
+		sb_need(out, 14);
+		b = out->cur;
+	}
+	*b++ = '"';
+	
+	out->cur = b;
+}
+
+static void emit_number(SB *out, double num)
+{
+	/*
+	 * This isn't exactly how JavaScript renders numbers,
+	 * but it should produce valid JSON for reasonable numbers
+	 * preserve precision well enough, and avoid some oddities
+	 * like 0.3 -> 0.299999999999999988898 .
+	 */
+	char buf[64];
+	sprintf(buf, "%.16g", num);
+	
+	if (number_is_valid(buf))
+		sb_puts(out, buf);
+	else
+		sb_puts(out, "null");
+}
+
+static bool tag_is_valid(unsigned int tag)
+{
+	return (/* tag >= JSON_NULL && */ tag <= JSON_OBJECT);
+}
+
+static bool number_is_valid(const char *num)
+{
+	return (parse_number(&num, NULL) && *num == '\0');
+}
+
+static bool expect_literal(const char **sp, const char *str)
+{
+	const char *s = *sp;
+	
+	while (*str != '\0')
+		if (*s++ != *str++)
+			return false;
+	
+	*sp = s;
+	return true;
+}
+
+/*
+ * Parses exactly 4 hex characters (capital or lowercase).
+ * Fails if any input chars are not [0-9A-Fa-f].
+ */
+static bool parse_hex16(const char **sp, uint16_t *out)
+{
+	const char *s = *sp;
+	uint16_t ret = 0;
+	uint16_t i;
+	uint16_t tmp;
+	char c;
+
+	for (i = 0; i < 4; i++) {
+		c = *s++;
+		if (c >= '0' && c <= '9')
+			tmp = c - '0';
+		else if (c >= 'A' && c <= 'F')
+			tmp = c - 'A' + 10;
+		else if (c >= 'a' && c <= 'f')
+			tmp = c - 'a' + 10;
+		else
+			return false;
+
+		ret <<= 4;
+		ret += tmp;
+	}
+	
+	if (out)
+		*out = ret;
+	*sp = s;
+	return true;
+}
+
+/*
+ * Encodes a 16-bit number into hexadecimal,
+ * writing exactly 4 hex chars.
+ */
+static int write_hex16(char *out, uint16_t val)
+{
+	const char *hex = "0123456789ABCDEF";
+	
+	*out++ = hex[(val >> 12) & 0xF];
+	*out++ = hex[(val >> 8)  & 0xF];
+	*out++ = hex[(val >> 4)  & 0xF];
+	*out++ = hex[ val        & 0xF];
+	
+	return 4;
+}
+
+bool json_check(const JsonNode *node, char errmsg[256])
+{
+	#define problem(...) do { \
+			if (errmsg != NULL) \
+				snprintf(errmsg, 256, __VA_ARGS__); \
+			return false; \
+		} while (0)
+	
+	if (node->key != NULL && !utf8_validate(node->key))
+		problem("key contains invalid UTF-8");
+	
+	if (!tag_is_valid(node->tag))
+		problem("tag is invalid (%u)", node->tag);
+	
+	if (node->tag == JSON_BOOL) {
+		if (node->bool_ != false && node->bool_ != true)
+			problem("bool_ is neither false (%d) nor true (%d)", (int)false, (int)true);
+	} else if (node->tag == JSON_STRING) {
+		if (node->string_ == NULL)
+			problem("string_ is NULL");
+		if (!utf8_validate(node->string_))
+			problem("string_ contains invalid UTF-8");
+	} else if (node->tag == JSON_ARRAY || node->tag == JSON_OBJECT) {
+		JsonNode *head = node->children.head;
+		JsonNode *tail = node->children.tail;
+		
+		if (head == NULL || tail == NULL) {
+			if (head != NULL)
+				problem("tail is NULL, but head is not");
+			if (tail != NULL)
+				problem("head is NULL, but tail is not");
+		} else {
+			JsonNode *child;
+			JsonNode *last = NULL;
+			
+			if (head->prev != NULL)
+				problem("First child's prev pointer is not NULL");
+			
+			for (child = head; child != NULL; last = child, child = child->next) {
+				if (child == node)
+					problem("node is its own child");
+				if (child->next == child)
+					problem("child->next == child (cycle)");
+				if (child->next == head)
+					problem("child->next == head (cycle)");
+				
+				if (child->parent != node)
+					problem("child does not point back to parent");
+				if (child->next != NULL && child->next->prev != child)
+					problem("child->next does not point back to child");
+				
+				if (node->tag == JSON_ARRAY && child->key != NULL)
+					problem("Array element's key is not NULL");
+				if (node->tag == JSON_OBJECT && child->key == NULL)
+					problem("Object member's key is NULL");
+				
+				if (!json_check(child, errmsg))
+					return false;
+			}
+			
+			if (last != tail)
+				problem("tail does not match pointer found by starting at head and following next links");
+		}
+	}
+	
+	return true;
+	
+	#undef problem
+}
diff --git a/contrib/ccan/json/json.h b/contrib/ccan/json/json.h
new file mode 100644
index 0000000..6eef48a
--- /dev/null
+++ b/contrib/ccan/json/json.h
@@ -0,0 +1,99 @@
+/* SPDX-License-Identifier: MIT
+ * Source: https://ccodearchive.net/info/json.html
+ * Copyright (C) 2011 Joseph A. Adams (joeyadams3.14159@gmail.com) */
+
+#ifndef CCAN_JSON_H
+#define CCAN_JSON_H
+
+#include <lib/defines.h>
+#include <stdbool.h>
+#include <stddef.h>
+
+typedef enum {
+	JSON_NULL,
+	JSON_BOOL,
+	JSON_STRING,
+	JSON_NUMBER,
+	JSON_ARRAY,
+	JSON_OBJECT,
+} JsonTag;
+
+typedef struct JsonNode JsonNode;
+
+struct JsonNode
+{
+	/* only if parent is an object or array (NULL otherwise) */
+	JsonNode *parent;
+	JsonNode *prev, *next;
+	
+	/* only if parent is an object (NULL otherwise) */
+	char *key; /* Must be valid UTF-8. */
+	
+	JsonTag tag;
+	union {
+		/* JSON_BOOL */
+		bool bool_;
+		
+		/* JSON_STRING */
+		char *string_; /* Must be valid UTF-8. */
+		
+		/* JSON_NUMBER */
+		double number_;
+		
+		/* JSON_ARRAY */
+		/* JSON_OBJECT */
+		struct {
+			JsonNode *head, *tail;
+		} children;
+	};
+};
+
+/*** Encoding, decoding, and validation ***/
+
+KR_EXPORT JsonNode   *json_decode         (const char *json);
+KR_EXPORT char       *json_encode         (const JsonNode *node);
+KR_EXPORT char       *json_encode_string  (const char *str);
+KR_EXPORT char       *json_stringify      (const JsonNode *node, const char *space);
+KR_EXPORT void        json_delete         (JsonNode *node);
+
+KR_EXPORT bool        json_validate       (const char *json);
+
+/*** Lookup and traversal ***/
+
+KR_EXPORT JsonNode   *json_find_element   (JsonNode *array, int index);
+KR_EXPORT JsonNode   *json_find_member    (JsonNode *object, const char *key);
+
+KR_EXPORT JsonNode   *json_first_child    (const JsonNode *node);
+
+#define json_foreach(i, object_or_array)            \
+	for ((i) = json_first_child(object_or_array);   \
+		 (i) != NULL;                               \
+		 (i) = (i)->next)
+
+/*** Construction and manipulation ***/
+
+KR_EXPORT JsonNode *json_mknull(void);
+KR_EXPORT JsonNode *json_mkbool(bool b);
+KR_EXPORT JsonNode *json_mkstring(const char *s);
+KR_EXPORT JsonNode *json_mknumber(double n);
+KR_EXPORT JsonNode *json_mkarray(void);
+KR_EXPORT JsonNode *json_mkobject(void);
+
+KR_EXPORT void json_append_element(JsonNode *array, JsonNode *element);
+KR_EXPORT void json_prepend_element(JsonNode *array, JsonNode *element);
+KR_EXPORT void json_append_member(JsonNode *object, const char *key, JsonNode *value);
+KR_EXPORT void json_prepend_member(JsonNode *object, const char *key, JsonNode *value);
+
+KR_EXPORT void json_remove_from_parent(JsonNode *node);
+
+/*** Debugging ***/
+
+/*
+ * Look for structure and encoding problems in a JsonNode or its descendents.
+ *
+ * If a problem is detected, return false, writing a description of the problem
+ * to errmsg (unless errmsg is NULL).
+ */
+KR_EXPORT bool json_check(const JsonNode *node, char errmsg[256]);
+
+#endif
diff --git a/contrib/ccan/json/json.spdx b/contrib/ccan/json/json.spdx
new file mode 100644
index 0000000..9943583
--- /dev/null
+++ b/contrib/ccan/json/json.spdx
@@ -0,0 +1,10 @@
+SPDXVersion: SPDX-2.1
+DataLicense: CC0-1.0
+SPDXID: SPDXRef-DOCUMENT
+DocumentName: ccan-json
+DocumentNamespace: http://spdx.org/spdxdocs/spdx-v2.1-d9b4db4c-062f-4add-89b6-f603224f5a2c
+
+PackageName: json
+PackageDownloadLocation: git+https://github.com/rustyrussell/ccan@f4eb3a18caf946ee6cc2cb57e2a0c6a6f115157f#ccan/json
+PackageOriginator: Person: Joseph A. Adams (joeyadams3.14159@gmail.com)
+PackageLicenseDeclared: MIT
diff --git a/contrib/cleanup.h b/contrib/cleanup.h
new file mode 100644
index 0000000..c9d170a
--- /dev/null
+++ b/contrib/cleanup.h
@@ -0,0 +1,25 @@
+/*  Copyright (C) CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+ *  SPDX-License-Identifier: GPL-3.0-or-later
+*/
+/**
+ * Cleanup attributes.
+ * @cond internal
+ */
+#pragma once
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+
+#define auto_free __attribute__((cleanup(_cleanup_free)))
+static inline void _cleanup_free(const void *p) {
+	free(*(char **)p);
+}
+#define auto_close __attribute__((cleanup(_cleanup_close)))
+static inline void _cleanup_close(int *p) {
+	if (*p != -1) close(*p);
+}
+#define auto_fclose __attribute__((cleanup(_cleanup_fclose)))
+static inline void _cleanup_fclose(FILE **p) {
+	if (*p) fclose(*p);
+}
+/* @endcond */
diff --git a/contrib/config.h b/contrib/config.h
new file mode 100644
index 0000000..336511f
--- /dev/null
+++ b/contrib/config.h
@@ -0,0 +1,7 @@
+/* Dummy file, no real configuration here
+ * SPDX-License-Identifier: GPL-3.0-or-later */
+#define HAVE_ATTRIBUTE_COLD 1
+#define HAVE_ATTRIBUTE_NORETURN 1
+#define HAVE_ATTRIBUTE_PURE 1
+#define HAVE_ATTRIBUTE_UNUSED 1
+#define HAVE_ATTRIBUTE_NONNULL 1
diff --git a/contrib/dynarray.h b/contrib/dynarray.h
new file mode 100644
index 0000000..7cbb686
--- /dev/null
+++ b/contrib/dynarray.h
@@ -0,0 +1,112 @@
+/*  Copyright (C) CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+ *  SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+/*!
+ * \brief Simple write-once allocation-optimal dynamic array.
+ *
+ * Include it into your .c file
+ *
+ * prefix - identifier prefix, e.g. ptr -> struct ptr_dynarray, ptr_dynarray_add(), ...
+ * ntype - data type to be stored. Let it be a number, pointer or small struct
+ * initial_capacity - how many data items will be allocated on stack and copied with assignment
+ *
+ * prefix_dynarray_add() - add a data item
+ * prefix_dynarray_fix() - call EVERYTIME the array is copied from some already invalid stack
+ * prefix_dynarray_free() - call EVERYTIME you dismiss all copies of the array
+ *
+ */
+
+#include <stdlib.h>
+#include <assert.h>
+
+#pragma once
+
+#define DYNARRAY_VISIBILITY_STATIC static
+#define DYNARRAY_VISIBILITY_PUBLIC
+#define DYNARRAY_VISIBILITY_LIBRARY __public__
+
+#define dynarray_declare(prefix, ntype, visibility, initial_capacity) \
+	typedef struct prefix ## _dynarray { \
+		ssize_t capacity; \
+		ssize_t size; \
+		ntype *(*arr)(struct prefix ## _dynarray *dynarray); \
+		ntype init[initial_capacity]; \
+		ntype *_arr; \
+	} prefix ## _dynarray_t; \
+	\
+	visibility ntype *prefix ## _dynarray_arr(prefix ## _dynarray_t *dynarray); \
+	visibility void prefix ## _dynarray_add(prefix ## _dynarray_t *dynarray, \
+	                                        ntype const *to_add); \
+	visibility void prefix ## _dynarray_free(prefix ## _dynarray_t *dynarray);
+
+#define dynarray_foreach(prefix, ntype, ptr, array) \
+	for (ntype *ptr = prefix ## _dynarray_arr(&(array)); \
+	     ptr < prefix ## _dynarray_arr(&(array)) + (array).size; ptr++)
+
+#define dynarray_define(prefix, ntype, visibility) \
+	\
+	static void prefix ## _dynarray_free__(struct prefix ## _dynarray *dynarray) \
+	{ \
+		if (dynarray->capacity > sizeof(dynarray->init) / sizeof(*dynarray->init)) { \
+			free(dynarray->_arr); \
+		} \
+	} \
+	\
+	__attribute__((unused)) \
+	visibility ntype *prefix ## _dynarray_arr(struct prefix ## _dynarray *dynarray) \
+	{ \
+		assert(dynarray->size <= dynarray->capacity); \
+		return (dynarray->capacity <= sizeof(dynarray->init) / sizeof(*dynarray->init) ? \
+			dynarray->init : dynarray->_arr); \
+	} \
+	\
+	static ntype *prefix ## _dynarray_arr_init__(struct prefix ## _dynarray *dynarray) \
+	{ \
+		assert(dynarray->capacity == sizeof(dynarray->init) / sizeof(*dynarray->init)); \
+		return dynarray->init; \
+	} \
+	\
+	static ntype *prefix ## _dynarray_arr_arr__(struct prefix ## _dynarray *dynarray) \
+	{ \
+		assert(dynarray->capacity > sizeof(dynarray->init) / sizeof(*dynarray->init)); \
+		return dynarray->_arr; \
+	} \
+	\
+	__attribute__((unused)) \
+	visibility void prefix ## _dynarray_add(struct prefix ## _dynarray *dynarray, \
+	                                        ntype const *to_add) \
+	{ \
+		if (dynarray->capacity < 0) { \
+			return; \
+		} \
+		if (dynarray->capacity == 0) { \
+			dynarray->capacity = sizeof(dynarray->init) / sizeof(*dynarray->init); \
+			dynarray->arr = prefix ## _dynarray_arr_init__; \
+		} \
+		if (dynarray->size >= dynarray->capacity) { \
+			ssize_t new_capacity = dynarray->capacity * 2 + 1; \
+			ntype *new_arr = calloc(new_capacity, sizeof(ntype)); \
+			if (new_arr == NULL) { \
+				prefix ## _dynarray_free__(dynarray); \
+				dynarray->capacity = dynarray->size = -1; \
+				return; \
+			} \
+			if (dynarray->capacity > 0) { \
+				memcpy(new_arr, prefix ## _dynarray_arr(dynarray), \
+				       dynarray->capacity * sizeof(ntype)); \
+			} \
+			prefix ## _dynarray_free__(dynarray); \
+			dynarray->_arr = new_arr; \
+			dynarray->capacity = new_capacity; \
+			dynarray->arr = prefix ## _dynarray_arr_arr__; \
+		} \
+		prefix ## _dynarray_arr(dynarray)[dynarray->size++] = *to_add; \
+	} \
+	\
+	__attribute__((unused)) \
+	visibility void prefix ## _dynarray_free(struct prefix ## _dynarray *dynarray) \
+	{ \
+		prefix ## _dynarray_free__(dynarray); \
+		memset(dynarray, 0, sizeof(*dynarray)); \
+	}
diff --git a/contrib/dynarray.spdx b/contrib/dynarray.spdx
new file mode 100644
index 0000000..02911c9
--- /dev/null
+++ b/contrib/dynarray.spdx
@@ -0,0 +1,10 @@
+SPDXVersion: SPDX-2.1
+DataLicense: CC0-1.0
+SPDXID: SPDXRef-DOCUMENT
+DocumentName: knotdns-dynarray
+DocumentNamespace: http://spdx.org/spdxdocs/spdx-v2.1-ce6423dd-ac6a-4e78-90c3-5cbdef1e252c
+
+PackageName: knotdns-dynarray
+PackageDownloadLocation: git+https://gitlab.nic.cz/knot/knot-dns.git@48c8b4f38cf5f7bf505c79b56adf7580688f6d3d#src/contrib/dynarray.h
+PackageOriginator: Organization: Knot DNS contributors
+PackageLicenseDeclared: GPL-3.0-or-later
diff --git a/contrib/licenses/BSD-MIT b/contrib/licenses/BSD-MIT
new file mode 100644
index 0000000..6e50b00
--- /dev/null
+++ b/contrib/licenses/BSD-MIT
@@ -0,0 +1,21 @@
+SPDX-License-Identifier: MIT
+SPDX-URL: https://spdx.org/licenses/MIT.html
+License-Text:
+
+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
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new file mode 100644
index 0000000..937f712
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diff --git a/contrib/licenses/LGPL2 b/contrib/licenses/LGPL2
new file mode 100644
index 0000000..682170d
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+
+  To apply these terms, attach the following notices to the library.  It is
+safest to attach them to the start of each source file to most effectively
+convey the exclusion of warranty; and each file should have at least the
+"copyright" line and a pointer to where the full notice is found.
+
+    <one line to give the library's name and a brief idea of what it does.>
+    Copyright (C) <year>  <name of author>
+
+    This library is free software; you can redistribute it and/or
+    modify it under the terms of the GNU Lesser General Public
+    License as published by the Free Software Foundation; either
+    version 2.1 of the License, or (at your option) any later version.
+
+    This library is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+    Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public
+    License along with this library; if not, write to the Free Software
+    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+
+Also add information on how to contact you by electronic and paper mail.
+
+You should also get your employer (if you work as a programmer) or your
+school, if any, to sign a "copyright disclaimer" for the library, if
+necessary.  Here is a sample; alter the names:
+
+  Yoyodyne, Inc., hereby disclaims all copyright interest in the
+  library `Frob' (a library for tweaking knobs) written by James Random Hacker.
+
+  <signature of Ty Coon>, 1 April 1990
+  Ty Coon, President of Vice
+
+That's all there is to it!
diff --git a/contrib/mempattern.c b/contrib/mempattern.c
new file mode 100644
index 0000000..6c237ea
--- /dev/null
+++ b/contrib/mempattern.c
@@ -0,0 +1,151 @@
+/*  Copyright (C) CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <stdlib.h>
+
+#include "contrib/mempattern.h"
+#include "contrib/ucw/mempool.h"
+
+static void mm_nofree(void *p)
+{
+	/* nop */
+}
+
+static void *mm_malloc(void *ctx, size_t n)
+{
+	(void)ctx;
+	return malloc(n);
+}
+
+void *mm_alloc(knot_mm_t *mm, size_t size)
+{
+	if (mm) {
+		return mm->alloc(mm->ctx, size);
+	} else {
+		return malloc(size);
+	}
+}
+
+void *mm_calloc(knot_mm_t *mm, size_t nmemb, size_t size)
+{
+	if (nmemb == 0 || size == 0) {
+		return NULL;
+	}
+	if (mm) {
+		size_t total_size = nmemb * size;
+		if (total_size / nmemb != size) { // Overflow check
+			return NULL;
+		}
+		void *mem = mm_alloc(mm, total_size);
+		if (mem == NULL) {
+			return NULL;
+		}
+		return memset(mem, 0, total_size);
+	} else {
+		return calloc(nmemb, size);
+	}
+}
+
+void *mm_realloc(knot_mm_t *mm, void *what, size_t size, size_t prev_size)
+{
+	if (mm) {
+		void *p = mm->alloc(mm->ctx, size);
+		if (p == NULL) {
+			return NULL;
+		} else {
+			if (what) {
+				memcpy(p, what,
+				       prev_size < size ? prev_size : size);
+			}
+			mm_free(mm, what);
+			return p;
+		}
+	} else {
+		return realloc(what, size);
+	}
+}
+
+char *mm_strdup(knot_mm_t *mm, const char *s)
+{
+	if (s == NULL) {
+		return NULL;
+	}
+	if (mm) {
+		size_t len = strlen(s) + 1;
+		void *mem = mm_alloc(mm, len);
+		if (mem == NULL) {
+			return NULL;
+		}
+		return memcpy(mem, s, len);
+	} else {
+		return strdup(s);
+	}
+}
+
+void mm_free(knot_mm_t *mm, void *what)
+{
+	if (mm) {
+		if (mm->free) {
+			mm->free(what);
+		}
+	} else {
+		free(what);
+	}
+}
+
+void mm_ctx_init(knot_mm_t *mm)
+{
+	mm->ctx = NULL;
+	mm->alloc = mm_malloc;
+	mm->free = free;
+}
+
+void mm_ctx_mempool(knot_mm_t *mm, size_t chunk_size)
+{
+	mm->ctx = mp_new(chunk_size);
+	mm->alloc = (knot_mm_alloc_t)mp_alloc;
+	mm->free = mm_nofree;
+}
+
+
+/* Code in addition to Knot's mempattern. */
+
+void *mm_malloc_aligned(void *ctx, size_t n)
+{
+	size_t alignment = (size_t)ctx;
+	void *res;
+	int err = posix_memalign(&res, alignment, n);
+	if (err == 0) {
+		return res;
+	} else {
+		assert(err == -1 && errno == ENOMEM);
+		return NULL;
+	}
+}
+
+knot_mm_t * mm_ctx_mempool2(size_t chunk_size)
+{
+	knot_mm_t pool_tmp;
+	mm_ctx_mempool(&pool_tmp, chunk_size);
+	knot_mm_t *pool = mm_alloc(&pool_tmp, sizeof(*pool));
+	if (!pool) {
+		mp_delete(pool_tmp.ctx);
+		return NULL;
+	}
+	memcpy(pool, &pool_tmp, sizeof(*pool));
+	return pool;
+}
+
diff --git a/contrib/mempattern.h b/contrib/mempattern.h
new file mode 100644
index 0000000..4db147a
--- /dev/null
+++ b/contrib/mempattern.h
@@ -0,0 +1,92 @@
+/*  Copyright (C) CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+/*!
+ * \brief Memory allocation related functions.
+ */
+
+#pragma once
+
+#include <libknot/mm_ctx.h>
+#include "contrib/ucw/mempool.h"
+#include "lib/defines.h"
+#include <assert.h>
+#include <stdint.h>
+
+/*! \brief Default memory block size. */
+#define MM_DEFAULT_BLKSIZE 4096
+
+/*! \brief Allocs using 'mm' if any, uses system malloc() otherwise. */
+KR_EXPORT
+void *mm_alloc(knot_mm_t *mm, size_t size);
+
+/*! \brief Callocs using 'mm' if any, uses system calloc() otherwise. */
+void *mm_calloc(knot_mm_t *mm, size_t nmemb, size_t size);
+
+/*! \brief Reallocs using 'mm' if any, uses system realloc() otherwise. */
+KR_EXPORT
+void *mm_realloc(knot_mm_t *mm, void *what, size_t size, size_t prev_size);
+
+/*! \brief Strdups using 'mm' if any, uses system strdup() otherwise. */
+char *mm_strdup(knot_mm_t *mm, const char *s);
+
+/*! \brief Free using 'mm' if any, uses system free() otherwise. */
+KR_EXPORT
+void mm_free(knot_mm_t *mm, void *what);
+
+/*! \brief Initialize default memory allocation context. */
+void mm_ctx_init(knot_mm_t *mm);
+
+/*! \brief Memory pool context. */
+void mm_ctx_mempool(knot_mm_t *mm, size_t chunk_size);
+
+
+/* API in addition to Knot's mempattern. */
+
+/*! \brief New memory pool context, allocated on itself. */
+KR_EXPORT knot_mm_t * mm_ctx_mempool2(size_t chunk_size);
+
+/*! \brief Delete a memory pool.  OK to call on a non-pool. */
+static inline void mm_ctx_delete(knot_mm_t *mm)
+{
+	/* The mp_alloc comparison bears a risk of missing the private symbol from knot. */
+	if (mm && mm->ctx && mm->alloc == (knot_mm_alloc_t)mp_alloc)
+		mp_delete(mm->ctx);
+}
+
+/*! \brief Readability: avoid const-casts in code. */
+static inline void free_const(const void *what)
+{
+	free((void *)what);
+}
+
+/*! \brief posix_memalign() wrapper. */
+void *mm_malloc_aligned(void *ctx, size_t n);
+
+/*! \brief Initialize mm with malloc+free with specified alignment (a power of two). */
+static inline void mm_ctx_init_aligned(knot_mm_t *mm, size_t alignment)
+{
+	assert(__builtin_popcount(alignment) == 1);
+	mm_ctx_init(mm);
+	mm->ctx = (uint8_t *)NULL + alignment; /*< roundabout to satisfy linters */
+	/* posix_memalign() doesn't allow alignment < sizeof(void*),
+	 * and there's no point in using it for small values anyway,
+	 * as plain malloc() guarantees at least max_align_t. */
+	if (alignment > sizeof(max_align_t)) {
+		mm->alloc = mm_malloc_aligned;
+	}
+}
+
diff --git a/contrib/meson.build b/contrib/meson.build
new file mode 100644
index 0000000..5d97e88
--- /dev/null
+++ b/contrib/meson.build
@@ -0,0 +1,28 @@
+# contrib
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+contrib_src = files([
+  'ccan/asprintf/asprintf.c',
+  'ccan/json/json.c',
+  'ucw/mempool.c',
+  'ucw/mempool-fmt.c',
+  'mempattern.c',
+  'murmurhash3/murmurhash3.c',
+  'base32hex.c',
+  'base64.c',
+  'base64url.c'
+])
+
+contrib_inc = include_directories('.', '..')
+
+contrib_lib = static_library(
+  'contrib',
+  contrib_src,
+  include_directories: contrib_inc,
+  dependencies: libknot,
+)
+
+contrib_dep = declare_dependency(
+  include_directories: contrib_inc,
+  link_with: contrib_lib,
+)
diff --git a/contrib/murmurhash3/LICENSE b/contrib/murmurhash3/LICENSE
new file mode 120000
index 0000000..fe25b01
--- /dev/null
+++ b/contrib/murmurhash3/LICENSE
@@ -0,0 +1 @@
+../licenses/CC0
\ No newline at end of file
diff --git a/contrib/murmurhash3/murmurhash3.c b/contrib/murmurhash3/murmurhash3.c
new file mode 100644
index 0000000..373c6ce
--- /dev/null
+++ b/contrib/murmurhash3/murmurhash3.c
@@ -0,0 +1,76 @@
+/* This is MurmurHash3. The original C++ code was placed in the public domain
+ * by its author, Austin Appleby.
+ *
+ * SPDX-License-Identifier: CC0-1.0
+ * Source: https://github.com/aappleby/smhasher/blob/master/src/MurmurHash3.cpp */
+
+#include "murmurhash3.h"
+#include "string.h"
+
+static inline uint32_t fmix(uint32_t h)
+{
+    h ^= h >> 16;
+    h *= 0x85ebca6b;
+    h ^= h >> 13;
+    h *= 0xc2b2ae35;
+    h ^= h >> 16;
+
+    return h;
+}
+
+static inline uint32_t rotl32(uint32_t x, int8_t r)
+{
+    return (x << r) | (x >> (32 - r));
+}
+
+uint32_t hash(const char* data, size_t len_)
+{
+    const int len = (int) len_;
+    const int nblocks = len / 4;
+
+    uint32_t h1 = 0xc062fb4a;
+
+    uint32_t c1 = 0xcc9e2d51;
+    uint32_t c2 = 0x1b873593;
+
+    //----------
+    // body
+
+    for(int i = 0; i < nblocks; ++i)
+    {
+        uint32_t k1;
+        memcpy(&k1, data + i * sizeof(k1), sizeof(k1));
+
+        k1 *= c1;
+        k1 = rotl32(k1, 15);
+        k1 *= c2;
+
+        h1 ^= k1;
+        h1 = rotl32(h1, 13);
+        h1 = h1*5+0xe6546b64;
+    }
+
+    //----------
+    // tail
+
+    const uint8_t * tail = (const uint8_t*)(data + nblocks*4);
+
+    uint32_t k1 = 0;
+
+    switch(len & 3)
+    {
+        case 3: k1 ^= tail[2] << 16;
+        case 2: k1 ^= tail[1] << 8;
+        case 1: k1 ^= tail[0];
+              k1 *= c1; k1 = rotl32(k1,15); k1 *= c2; h1 ^= k1;
+    }
+
+    //----------
+    // finalization
+
+    h1 ^= len;
+
+    h1 = fmix(h1);
+
+    return h1;
+}
diff --git a/contrib/murmurhash3/murmurhash3.h b/contrib/murmurhash3/murmurhash3.h
new file mode 100644
index 0000000..d849961
--- /dev/null
+++ b/contrib/murmurhash3/murmurhash3.h
@@ -0,0 +1,9 @@
+/* SPDX-License-Identifier: CC0-1.0
+ * Source: https://github.com/aappleby/smhasher/blob/master/src/MurmurHash3.cpp */
+
+#pragma once
+
+#include <stdlib.h>
+#include <stdint.h>
+
+uint32_t hash(const char* data, size_t len);
diff --git a/contrib/murmurhash3/murmurhash3.spdx b/contrib/murmurhash3/murmurhash3.spdx
new file mode 100644
index 0000000..7ce5a54
--- /dev/null
+++ b/contrib/murmurhash3/murmurhash3.spdx
@@ -0,0 +1,10 @@
+SPDXVersion: SPDX-2.1
+DataLicense: CC0-1.0
+SPDXID: SPDXRef-DOCUMENT
+DocumentName: ccan-json
+DocumentNamespace: http://spdx.org/spdxdocs/spdx-v2.1-d9b4db4c-062f-4add-89b6-f603224f5a2c
+
+PackageName: json
+PackageDownloadLocation: git+https://github.com/aappleby/smhasher.git@73e075b203d9c76cd1e20d6c8907c2983d653f33#MurmurHash3.cpp
+PackageOriginator: Person: Austin Appleby (aappleby@gmail.com)
+PackageLicenseDeclared: CC0-1.0
diff --git a/contrib/ucw/LICENSE b/contrib/ucw/LICENSE
new file mode 120000
index 0000000..0cb7f47
--- /dev/null
+++ b/contrib/ucw/LICENSE
@@ -0,0 +1 @@
+../licenses/LGPL2
\ No newline at end of file
diff --git a/contrib/ucw/alloc.h b/contrib/ucw/alloc.h
new file mode 100644
index 0000000..a6feadc
--- /dev/null
+++ b/contrib/ucw/alloc.h
@@ -0,0 +1,38 @@
+/*
+ *	UCW Library -- Generic allocators
+ *
+ *	(c) 2014 Martin Mares <mj@ucw.cz>
+ *	SPDX-License-Identifier: LGPL-2.1-or-later
+ *	Source: https://www.ucw.cz/libucw/
+ */
+
+#ifndef _UCW_ALLOC_H
+#define _UCW_ALLOC_H
+
+/**
+ * This structure describes a generic allocator. It provides pointers
+ * to three functions, which handle the actual (re)allocations.
+ **/
+struct ucw_allocator {
+  void * (*alloc)(struct ucw_allocator *alloc, size_t size);
+  void * (*realloc)(struct ucw_allocator *alloc, void *ptr, size_t old_size, size_t new_size);
+  void (*free)(struct ucw_allocator *alloc, void *ptr);
+};
+
+/* alloc-std.c */
+
+/**
+ * [[std]]
+ * This allocator uses <<basics:xmalloc()>>, <<basics:xrealloc()>> and <<basics:xfree()>>. The memory
+ * it allocates is left uninitialized.
+ **/
+extern struct ucw_allocator ucw_allocator_std;
+
+/**
+ * [[zeroing]]
+ * This allocator uses <<basics:xmalloc()>>, <<basics:xrealloc()>> and <<basics:xfree()>>. All memory
+ * is zeroed upon allocation.
+ **/
+extern struct ucw_allocator ucw_allocator_zeroed;
+
+#endif
diff --git a/contrib/ucw/config.h b/contrib/ucw/config.h
new file mode 100644
index 0000000..3c94104
--- /dev/null
+++ b/contrib/ucw/config.h
@@ -0,0 +1,58 @@
+/*
+ *	UCW Library -- Configuration-Dependent Definitions
+ *
+ *	(c) 1997--2012 Martin Mares <mj@ucw.cz>
+ *	(c) 2006 Robert Spalek <robert@ucw.cz>
+ *
+ *	SPDX-License-Identifier: LGPL-2.1-or-later
+ *	Source: https://www.ucw.cz/libucw/
+ */
+
+#ifndef _UCW_CONFIG_H
+#define _UCW_CONFIG_H
+
+/* Default page size and pointer alignment */
+#ifndef CPU_PAGE_SIZE
+#define CPU_PAGE_SIZE 4096
+#endif
+#define CPU_STRUCT_ALIGN sizeof(void *)
+
+/* Tell libc we're going to use all extensions available */
+
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+
+/* Types (based on standard C99 integers) */
+
+#include <stddef.h>
+#include <stdint.h>
+
+typedef uint8_t byte;			/** Exactly 8 bits, unsigned **/
+typedef uint8_t u8;			/** Exactly 8 bits, unsigned **/
+typedef int8_t s8;			/** Exactly 8 bits, signed **/
+typedef uint16_t u16;			/** Exactly 16 bits, unsigned **/
+typedef int16_t s16;			/** Exactly 16 bits, signed **/
+typedef uint32_t u32;			/** Exactly 32 bits, unsigned **/
+typedef int32_t s32;			/** Exactly 32 bits, signed **/
+typedef uint64_t u64;			/** Exactly 64 bits, unsigned **/
+typedef int64_t s64;			/** Exactly 64 bits, signed **/
+
+
+#ifndef uint /* Redefining typedef is a C11 feature. */
+typedef unsigned int uint;		/** A better pronounceable alias for `unsigned int` **/
+#define uint uint
+#endif
+
+typedef s64 timestamp_t;		/** Milliseconds since an unknown epoch **/
+
+// FIXME: This should be removed soon
+typedef uint uns;			/** Backwards compatible alias for `uint' ***/
+
+#ifdef CONFIG_UCW_LARGE_FILES
+typedef s64 ucw_off_t;			/** File position (either 32- or 64-bit, depending on `CONFIG_UCW_LARGE_FILES`). **/
+#else
+typedef s32 ucw_off_t;
+#endif
+
+#endif
diff --git a/contrib/ucw/lib.h b/contrib/ucw/lib.h
new file mode 100644
index 0000000..89b3a20
--- /dev/null
+++ b/contrib/ucw/lib.h
@@ -0,0 +1,125 @@
+/*
+ *	The UCW Library -- Miscellaneous Functions
+ *
+ *	(c) 1997--2014 Martin Mares <mj@ucw.cz>
+ *	(c) 2005--2014 Tomas Valla <tom@ucw.cz>
+ *	(c) 2006 Robert Spalek <robert@ucw.cz>
+ *	(c) 2007 Pavel Charvat <pchar@ucw.cz>
+ *
+ *	SPDX-License-Identifier: LGPL-2.1-or-later
+ *	Source: https://www.ucw.cz/libucw/
+ */
+
+#ifndef _UCW_LIB_H
+#define _UCW_LIB_H
+
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdlib.h>
+
+#ifdef CONFIG_UCW_CLEAN_ABI
+#define assert_failed ucw_assert_failed
+#define assert_failed_msg ucw_assert_failed_msg
+#define assert_failed_noinfo ucw_assert_failed_noinfo
+#define big_alloc ucw_big_alloc
+#define big_alloc_zero ucw_big_alloc_zero
+#define big_free ucw_big_free
+#define die ucw_die
+#define log_die_hook ucw_log_die_hook
+#define log_file ucw_log_file
+#define log_fork ucw_log_fork
+#define log_init ucw_log_init
+#define log_pid ucw_log_pid
+#define log_title ucw_log_title
+#define msg ucw_msg
+#define page_alloc ucw_page_alloc
+#define page_alloc_zero ucw_page_alloc_zero
+#define page_free ucw_page_free
+#define page_realloc ucw_page_realloc
+#define random_max ucw_random_max
+#define random_max_u64 ucw_random_max_u64
+#define random_u32 ucw_random_u32
+#define random_u64 ucw_random_u64
+#define vdie ucw_vdie
+#define vmsg ucw_vmsg
+#define xfree ucw_xfree
+#define xmalloc ucw_xmalloc
+#define xmalloc_zero ucw_xmalloc_zero
+#define xrealloc ucw_xrealloc
+#define xstrdup ucw_xstrdup
+#endif
+
+/*** === Macros for handling structures, offsets and alignment ***/
+
+#define CHECK_PTR_TYPE(x, type) ((x)-(type)(x) + (type)(x))		/** Check that a pointer @x is of type @type. Fail compilation if not. **/
+#define PTR_TO(s, i) &((s*)0)->i					/** Return OFFSETOF() in form of a pointer. **/
+#define OFFSETOF(s, i) ((uint)offsetof(s, i))				/** Offset of item @i from the start of structure @s **/
+#define SKIP_BACK(s, i, p) ((s *)((char *)p - OFFSETOF(s, i)))		/** Given a pointer @p to item @i of structure @s, return a pointer to the start of the struct. **/
+
+/** Align an integer @s to the nearest higher multiple of @a (which should be a power of two) **/
+#define ALIGN_TO(s, a) (((s)+a-1)&~(a-1))
+
+/** Align a pointer @p to the nearest higher multiple of @s. **/
+#define ALIGN_PTR(p, s) ((uintptr_t)(p) % (s) ? (typeof(p))((uintptr_t)(p) + (s) - (uintptr_t)(p) % (s)) : (p))
+
+#define UNALIGNED_PART(ptr, type) (((uintptr_t) (ptr)) % sizeof(type))
+
+/*** === Other utility macros ***/
+
+#define MIN(a,b) (((a)<(b))?(a):(b))			/** Minimum of two numbers **/
+#define MAX(a,b) (((a)>(b))?(a):(b))			/** Maximum of two numbers **/
+#define CLAMP(x,min,max) ({ typeof(x) _t=x; (_t < min) ? min : (_t > max) ? max : _t; })	/** Clip a number @x to interval [@min,@max] **/
+#define ABS(x) ((x) < 0 ? -(x) : (x))			/** Absolute value **/
+#define ARRAY_SIZE(a) (sizeof(a)/sizeof(*(a)))		/** The number of elements of an array **/
+#define STRINGIFY(x) #x					/** Convert macro parameter to a string **/
+#define STRINGIFY_EXPANDED(x) STRINGIFY(x)		/** Convert an expanded macro parameter to a string **/
+#define GLUE(x,y) x##y					/** Glue two tokens together **/
+#define GLUE_(x,y) x##_##y				/** Glue two tokens together, separating them by an underscore **/
+
+#define COMPARE(x,y) do { if ((x)<(y)) return -1; if ((x)>(y)) return 1; } while(0)		/** Numeric comparison function for qsort() **/
+#define REV_COMPARE(x,y) COMPARE(y,x)								/** Reverse numeric comparison **/
+#define COMPARE_LT(x,y) do { if ((x)<(y)) return 1; if ((x)>(y)) return 0; } while(0)
+#define COMPARE_GT(x,y) COMPARE_LT(y,x)
+
+#define	ROL(x, bits) (((x) << (bits)) | ((uint)(x) >> (sizeof(uint)*8 - (bits))))		/** Bitwise rotation of an unsigned int to the left **/
+#define	ROR(x, bits) (((uint)(x) >> (bits)) | ((x) << (sizeof(uint)*8 - (bits))))		/** Bitwise rotation of an unsigned int to the right **/
+
+/*** === Shortcuts for GCC Extensions ***/
+
+#ifdef __GNUC__
+
+#include "ccan/compiler/compiler.h"
+#define FORMAT_CHECK(x,y,z) __attribute__((format(x,y,z)))		/** Checking of printf-like format strings **/
+#define likely(x) __builtin_expect((x),1)				/** Use `if (likely(@x))` if @x is almost always true **/
+#define unlikely(x) __builtin_expect((x),0)				/** Use `if (unlikely(@x))` to hint that @x is almost always false **/
+
+#if __GNUC__ >= 4 || __GNUC__ == 3 && __GNUC_MINOR__ >= 3
+#define ALWAYS_INLINE inline __attribute__((always_inline))		/** Forcibly inline **/
+#define NO_INLINE __attribute__((noinline))				/** Forcibly uninline **/
+#else
+#define ALWAYS_INLINE inline
+#endif
+
+#if __GNUC__ >= 4
+#define LIKE_MALLOC __attribute__((malloc))				/** Function returns a "new" pointer **/
+#define SENTINEL_CHECK __attribute__((sentinel))			/** The last argument must be NULL **/
+#else
+#define LIKE_MALLOC
+#define SENTINEL_CHECK
+#endif
+
+#else
+#error This program requires the GNU C compiler.
+#endif
+
+/***
+ * [[logging]]
+ *
+ * === Basic logging functions (see <<log:,Logging>> and <ucw/log.h> for more)
+ ***/
+
+#define DBG(x, ...) do { } while(0)
+#define DBG_SPOT do { } while(0)
+#define ASSERT(x)
+
+#endif
diff --git a/contrib/ucw/libucw.spdx b/contrib/ucw/libucw.spdx
new file mode 100644
index 0000000..e18b2ea
--- /dev/null
+++ b/contrib/ucw/libucw.spdx
@@ -0,0 +1,10 @@
+SPDXVersion: SPDX-2.1
+DataLicense: CC0-1.0
+SPDXID: SPDXRef-DOCUMENT
+DocumentName: libucw
+DocumentNamespace: http://spdx.org/spdxdocs/spdx-v2.1-c3d39e26-6b71-46d4-88ea-e52750932ff3
+
+PackageName: libucw
+PackageDownloadLocation: git://git.ucw.cz/libucw.git@f1bde7104b04d5254d1d1d7dcc8de790a43a416f#ucw/
+PackageOriginator: Organization: United Computer Wizards
+PackageLicenseDeclared: LGPL-2.1-or-later
diff --git a/contrib/ucw/mempool-fmt.c b/contrib/ucw/mempool-fmt.c
new file mode 100644
index 0000000..22f3a50
--- /dev/null
+++ b/contrib/ucw/mempool-fmt.c
@@ -0,0 +1,99 @@
+/*
+ *  UCW Library -- Memory Pools (Formatting)
+ *
+ *  (c) 2005 Martin Mares <mj@ucw.cz>
+ *  (c) 2007 Pavel Charvat <pchar@ucw.cz>
+ *  SPDX-License-Identifier: LGPL-2.1-or-later
+ *  Source: https://www.ucw.cz/libucw/
+ */
+
+#include <ucw/lib.h>
+#include <ucw/mempool.h>
+
+#include <stdio.h>
+#include <string.h>
+
+/* FIXME: migrate to Knot DNS version of mempools. */
+#pragma GCC diagnostic ignored "-Wpointer-arith"
+
+static char *
+mp_vprintf_at(struct mempool *mp, size_t ofs, const char *fmt, va_list args)
+{
+  char *ret = mp_grow(mp, ofs + 1) + ofs;
+  va_list args2;
+  va_copy(args2, args);
+  int cnt = vsnprintf(ret, mp_avail(mp) - ofs, fmt, args2);
+  va_end(args2);
+  if (cnt < 0)
+    {
+      /* Our C library doesn't support C99 return value of vsnprintf, so we need to iterate */
+      do
+  {
+    ret = mp_expand(mp) + ofs;
+    va_copy(args2, args);
+    cnt = vsnprintf(ret, mp_avail(mp) - ofs, fmt, args2);
+    va_end(args2);
+  }
+      while (cnt < 0);
+    }
+  else if ((uint)cnt >= mp_avail(mp) - ofs)
+    {
+      ret = mp_grow(mp, ofs + cnt + 1) + ofs;
+      va_copy(args2, args);
+      vsnprintf(ret, cnt + 1, fmt, args2);
+      va_end(args2);
+    }
+  mp_end(mp, ret + cnt + 1);
+  return ret - ofs;
+}
+
+char *
+mp_vprintf(struct mempool *mp, const char *fmt, va_list args)
+{
+  mp_start(mp, 1);
+  return mp_vprintf_at(mp, 0, fmt, args);
+}
+
+char *
+mp_printf(struct mempool *p, const char *fmt, ...)
+{
+  va_list args;
+  va_start(args, fmt);
+  char *res = mp_vprintf(p, fmt, args);
+  va_end(args);
+  return res;
+}
+
+char *
+mp_vprintf_append(struct mempool *mp, char *ptr, const char *fmt, va_list args)
+{
+  size_t ofs = mp_open(mp, ptr);
+  ASSERT(ofs && !ptr[ofs - 1]);
+  return mp_vprintf_at(mp, ofs - 1, fmt, args);
+}
+
+char *
+mp_printf_append(struct mempool *mp, char *ptr, const char *fmt, ...)
+{
+  va_list args;
+  va_start(args, fmt);
+  char *res = mp_vprintf_append(mp, ptr, fmt, args);
+  va_end(args);
+  return res;
+}
+
+#ifdef TEST
+
+int main(void)
+{
+  struct mempool *mp = mp_new(64);
+  char *x = mp_printf(mp, "<Hello, %s!>", "World");
+  fputs(x, stdout);
+  x = mp_printf_append(mp, x, "<Appended>");
+  fputs(x, stdout);
+  x = mp_printf(mp, "<Hello, %50s!>\n", "World");
+  fputs(x, stdout);
+  return 0;
+}
+
+#endif
diff --git a/contrib/ucw/mempool.c b/contrib/ucw/mempool.c
new file mode 100644
index 0000000..314b58e
--- /dev/null
+++ b/contrib/ucw/mempool.c
@@ -0,0 +1,601 @@
+/*
+ *	UCW Library -- Memory Pools (One-Time Allocation)
+ *
+ *	(c) 1997--2014 Martin Mares <mj@ucw.cz>
+ *	(c) 2007--2015 Pavel Charvat <pchar@ucw.cz>
+ *
+ * 	SPDX-License-Identifier: LGPL-2.1-or-later
+ * 	Source: https://www.ucw.cz/libucw/
+ */
+
+#undef LOCAL_DEBUG
+
+#include <ucw/config.h>
+#include <ucw/lib.h>
+#include <ucw/alloc.h>
+#include <ucw/mempool.h>
+
+#include <string.h>
+#include <stdlib.h>
+
+/* FIXME: migrate to Knot DNS version of mempools. */
+#pragma GCC diagnostic ignored "-Wpointer-arith"
+
+#define MP_CHUNK_TAIL ALIGN_TO(sizeof(struct mempool_chunk), CPU_STRUCT_ALIGN)
+#define MP_SIZE_MAX (SIZE_MAX - MP_CHUNK_TAIL - CPU_PAGE_SIZE)
+
+struct mempool_chunk {
+#ifdef CONFIG_DEBUG
+  struct mempool *pool;		// Can be useful when analysing coredump for memory leaks
+#endif
+  struct mempool_chunk *next;
+  size_t size;
+};
+
+static size_t
+mp_align_size(size_t size)
+{
+#ifdef CONFIG_UCW_POOL_IS_MMAP
+  size = MAX(size, 64 + MP_CHUNK_TAIL);
+  return ALIGN_TO(size, CPU_PAGE_SIZE) - MP_CHUNK_TAIL;
+#else
+  return ALIGN_TO(size, CPU_STRUCT_ALIGN);
+#endif
+}
+
+static void *mp_allocator_alloc(struct ucw_allocator *a, size_t size)
+{
+  struct mempool *mp = (struct mempool *) a;
+  return mp_alloc_fast(mp, size);
+}
+
+static void *mp_allocator_realloc(struct ucw_allocator *a, void *ptr, size_t old_size, size_t new_size)
+{
+  if (new_size <= old_size)
+    return ptr;
+
+  /*
+   *  In the future, we might want to do something like mp_realloc(),
+   *  but we have to check that it is indeed the last block in the pool.
+   */
+  struct mempool *mp = (struct mempool *) a;
+  void *new = mp_alloc_fast(mp, new_size);
+  memcpy(new, ptr, old_size);
+  return new;
+}
+
+static void mp_allocator_free(struct ucw_allocator *a UNUSED, void *ptr UNUSED)
+{
+  // Does nothing
+}
+
+void
+mp_init(struct mempool *pool, size_t chunk_size)
+{
+  chunk_size = mp_align_size(MAX(sizeof(struct mempool), chunk_size));
+  *pool = (struct mempool) {
+    .allocator = {
+      .alloc = mp_allocator_alloc,
+      .realloc = mp_allocator_realloc,
+      .free = mp_allocator_free,
+    },
+    .chunk_size = chunk_size,
+    .threshold = chunk_size >> 1,
+    .last_big = &pool->last_big
+  };
+}
+
+static void *
+mp_new_big_chunk(struct mempool *pool, size_t size)
+{
+  struct mempool_chunk *chunk;
+  chunk = malloc(size + MP_CHUNK_TAIL);
+  if (!chunk)
+    return NULL;
+  chunk = (struct mempool_chunk *)((char *)chunk + size);
+  chunk->size = size;
+  if (pool)
+    pool->total_size += size + MP_CHUNK_TAIL;
+  return chunk;
+}
+
+static void
+mp_free_big_chunk(struct mempool *pool, struct mempool_chunk *chunk)
+{
+  pool->total_size -= chunk->size + MP_CHUNK_TAIL;
+  free((void *)chunk - chunk->size);
+}
+
+static void *
+mp_new_chunk(struct mempool *pool, size_t size)
+{
+#ifdef CONFIG_UCW_POOL_IS_MMAP
+  struct mempool_chunk *chunk;
+  chunk = page_alloc(size + MP_CHUNK_TAIL) + size;
+  chunk->size = size;
+  if (pool)
+    pool->total_size += size + MP_CHUNK_TAIL;
+  return chunk;
+#else
+  return mp_new_big_chunk(pool, size);
+#endif
+}
+
+static void
+mp_free_chunk(struct mempool *pool, struct mempool_chunk *chunk)
+{
+#ifdef CONFIG_UCW_POOL_IS_MMAP
+  pool->total_size -= chunk->size + MP_CHUNK_TAIL;
+  page_free((void *)chunk - chunk->size, chunk->size + MP_CHUNK_TAIL);
+#else
+  mp_free_big_chunk(pool, chunk);
+#endif
+}
+
+struct mempool *
+mp_new(size_t chunk_size)
+{
+  chunk_size = mp_align_size(MAX(sizeof(struct mempool), chunk_size));
+  struct mempool_chunk *chunk = mp_new_chunk(NULL, chunk_size);
+  struct mempool *pool = (void *)chunk - chunk_size;
+  DBG("Creating mempool %p with %u bytes long chunks", pool, chunk_size);
+  chunk->next = NULL;
+#ifdef CONFIG_DEBUG
+  chunk->pool = pool;
+#endif
+  *pool = (struct mempool) {
+    .allocator = {
+      .alloc = mp_allocator_alloc,
+      .realloc = mp_allocator_realloc,
+      .free = mp_allocator_free,
+    },
+    .state = { .free = { chunk_size - sizeof(*pool) }, .last = { chunk } },
+    .chunk_size = chunk_size,
+    .threshold = chunk_size >> 1,
+    .last_big = &pool->last_big,
+    .total_size = chunk->size + MP_CHUNK_TAIL,
+  };
+  return pool;
+}
+
+static void
+mp_free_chain(struct mempool *pool, struct mempool_chunk *chunk)
+{
+  while (chunk)
+    {
+      struct mempool_chunk *next = chunk->next;
+      mp_free_chunk(pool, chunk);
+      chunk = next;
+    }
+}
+
+static void
+mp_free_big_chain(struct mempool *pool, struct mempool_chunk *chunk)
+{
+  while (chunk)
+    {
+      struct mempool_chunk *next = chunk->next;
+      mp_free_big_chunk(pool, chunk);
+      chunk = next;
+    }
+}
+
+void
+mp_delete(struct mempool *pool)
+{
+  DBG("Deleting mempool %p", pool);
+  mp_free_big_chain(pool, pool->state.last[1]);
+  mp_free_chain(pool, pool->unused);
+  mp_free_chain(pool, pool->state.last[0]); // can contain the mempool structure
+}
+
+void
+mp_flush(struct mempool *pool)
+{
+  mp_free_big_chain(pool, pool->state.last[1]);
+  struct mempool_chunk *chunk, *next;
+  for (chunk = pool->state.last[0]; chunk && (void *)chunk - chunk->size != pool; chunk = next)
+    {
+      next = chunk->next;
+      chunk->next = pool->unused;
+      pool->unused = chunk;
+    }
+  pool->state.last[0] = chunk;
+  pool->state.free[0] = chunk ? chunk->size - sizeof(*pool) : 0;
+  pool->state.last[1] = NULL;
+  pool->state.free[1] = 0;
+  pool->state.next = NULL;
+  pool->last_big = &pool->last_big;
+}
+
+static void
+mp_stats_chain(struct mempool *pool, struct mempool_chunk *chunk, struct mempool_stats *stats, uint idx)
+{
+  while (chunk)
+    {
+      stats->chain_size[idx] += chunk->size + MP_CHUNK_TAIL;
+      stats->chain_count[idx]++;
+      if (idx < 2)
+	{
+	  stats->used_size += chunk->size;
+	  if ((byte *)pool == (byte *)chunk - chunk->size)
+	    stats->used_size -= sizeof(*pool);
+	}
+      chunk = chunk->next;
+    }
+  stats->total_size += stats->chain_size[idx];
+}
+
+void
+mp_stats(struct mempool *pool, struct mempool_stats *stats)
+{
+  bzero(stats, sizeof(*stats));
+  mp_stats_chain(pool, pool->state.last[0], stats, 0);
+  mp_stats_chain(pool, pool->state.last[1], stats, 1);
+  mp_stats_chain(pool, pool->unused, stats, 2);
+  stats->used_size -= pool->state.free[0] + pool->state.free[1];
+  ASSERT(stats->total_size == pool->total_size);
+  ASSERT(stats->used_size <= stats->total_size);
+}
+
+u64
+mp_total_size(struct mempool *pool)
+{
+  return pool->total_size;
+}
+
+void
+mp_shrink(struct mempool *pool, u64 min_total_size)
+{
+  while (1)
+    {
+      struct mempool_chunk *chunk = pool->unused;
+      if (!chunk || pool->total_size - (chunk->size + MP_CHUNK_TAIL) < min_total_size)
+	break;
+      pool->unused = chunk->next;
+      mp_free_chunk(pool, chunk);
+    }
+}
+
+void *
+mp_alloc_internal(struct mempool *pool, size_t size)
+{
+  struct mempool_chunk *chunk;
+  if (size <= pool->threshold)
+    {
+      pool->idx = 0;
+      if (pool->unused)
+        {
+	  chunk = pool->unused;
+	  pool->unused = chunk->next;
+	}
+      else
+	{
+	  chunk = mp_new_chunk(pool, pool->chunk_size);
+#ifdef CONFIG_DEBUG
+	  chunk->pool = pool;
+#endif
+	}
+      chunk->next = pool->state.last[0];
+      pool->state.last[0] = chunk;
+      pool->state.free[0] = pool->chunk_size - size;
+      return (void *)chunk - pool->chunk_size;
+    }
+  else if (likely(size <= MP_SIZE_MAX))
+    {
+      pool->idx = 1;
+      size_t aligned = ALIGN_TO(size, CPU_STRUCT_ALIGN);
+      chunk = mp_new_big_chunk(pool, aligned);
+      chunk->next = pool->state.last[1];
+#ifdef CONFIG_DEBUG
+      chunk->pool = pool;
+#endif
+      pool->state.last[1] = chunk;
+      pool->state.free[1] = aligned - size;
+      return pool->last_big = (void *)chunk - aligned;
+    }
+  else
+    return NULL;
+}
+
+void *
+mp_alloc(struct mempool *pool, size_t size)
+{
+  return mp_alloc_fast(pool, size);
+}
+
+void *
+mp_alloc_noalign(struct mempool *pool, size_t size)
+{
+  return mp_alloc_fast_noalign(pool, size);
+}
+
+void *
+mp_alloc_zero(struct mempool *pool, size_t size)
+{
+  void *ptr = mp_alloc_fast(pool, size);
+  bzero(ptr, size);
+  return ptr;
+}
+
+void *
+mp_start_internal(struct mempool *pool, size_t size)
+{
+  void *ptr = mp_alloc_internal(pool, size);
+  if (!ptr)
+    return NULL;
+  pool->state.free[pool->idx] += size;
+  return ptr;
+}
+
+void *
+mp_start(struct mempool *pool, size_t size)
+{
+  return mp_start_fast(pool, size);
+}
+
+void *
+mp_start_noalign(struct mempool *pool, size_t size)
+{
+  return mp_start_fast_noalign(pool, size);
+}
+
+void *
+mp_grow_internal(struct mempool *pool, size_t size)
+{
+  if (unlikely(size > MP_SIZE_MAX))
+    return NULL;
+  size_t avail = mp_avail(pool);
+  void *ptr = mp_ptr(pool);
+  if (pool->idx)
+    {
+      size_t amortized = likely(avail <= MP_SIZE_MAX / 2) ? avail * 2 : MP_SIZE_MAX;
+      amortized = MAX(amortized, size);
+      amortized = ALIGN_TO(amortized, CPU_STRUCT_ALIGN);
+      struct mempool_chunk *chunk = pool->state.last[1], *next = chunk->next;
+      pool->total_size = pool->total_size - chunk->size + amortized;
+      void *nptr = realloc(ptr, amortized + MP_CHUNK_TAIL);
+      if (!nptr)
+        return NULL;
+      ptr = nptr;
+      chunk = ptr + amortized;
+      chunk->next = next;
+      chunk->size = amortized;
+      pool->state.last[1] = chunk;
+      pool->state.free[1] = amortized;
+      pool->last_big = ptr;
+      return ptr;
+    }
+  else
+    {
+      void *p = mp_start_internal(pool, size);
+      memcpy(p, ptr, avail);
+      return p;
+    }
+}
+
+size_t
+mp_open(struct mempool *pool, void *ptr)
+{
+  return mp_open_fast(pool, ptr);
+}
+
+void *
+mp_realloc(struct mempool *pool, void *ptr, size_t size)
+{
+  return mp_realloc_fast(pool, ptr, size);
+}
+
+void *
+mp_realloc_zero(struct mempool *pool, void *ptr, size_t size)
+{
+  size_t old_size = mp_open_fast(pool, ptr);
+  ptr = mp_grow(pool, size);
+  if (size > old_size)
+    bzero(ptr + old_size, size - old_size);
+  mp_end(pool, ptr + size);
+  return ptr;
+}
+
+void *
+mp_spread_internal(struct mempool *pool, void *p, size_t size)
+{
+  void *old = mp_ptr(pool);
+  void *new = mp_grow_internal(pool, p-old+size);
+  if (!new) {
+    return NULL;
+  }
+  return p-old+new;
+}
+
+void
+mp_restore(struct mempool *pool, struct mempool_state *state)
+{
+  struct mempool_chunk *chunk, *next;
+  struct mempool_state s = *state;
+  for (chunk = pool->state.last[0]; chunk != s.last[0]; chunk = next)
+    {
+      next = chunk->next;
+      chunk->next = pool->unused;
+      pool->unused = chunk;
+    }
+  for (chunk = pool->state.last[1]; chunk != s.last[1]; chunk = next)
+    {
+      next = chunk->next;
+      mp_free_big_chunk(pool, chunk);
+    }
+  pool->state = s;
+  pool->last_big = &pool->last_big;
+}
+
+struct mempool_state *
+mp_push(struct mempool *pool)
+{
+  struct mempool_state state = pool->state;
+  struct mempool_state *p = mp_alloc_fast(pool, sizeof(*p));
+  *p = state;
+  pool->state.next = p;
+  return p;
+}
+
+void
+mp_pop(struct mempool *pool)
+{
+  ASSERT(pool->state.next);
+  mp_restore(pool, pool->state.next);
+}
+
+#ifdef TEST
+
+#include <ucw/getopt.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+
+static void
+fill(byte *ptr, uint len, uint magic)
+{
+  while (len--)
+    *ptr++ = (magic++ & 255);
+}
+
+static void
+check(byte *ptr, uint len, uint magic, uint align)
+{
+  ASSERT(!((uintptr_t)ptr & (align - 1)));
+  while (len--)
+    if (*ptr++ != (magic++ & 255))
+      ASSERT(0);
+}
+
+int main(int argc, char **argv)
+{
+  srand(time(NULL));
+  log_init(argv[0]);
+  cf_def_file = NULL;
+  if (cf_getopt(argc, argv, CF_SHORT_OPTS, CF_NO_LONG_OPTS, NULL) >= 0 || argc != optind)
+    die("Invalid usage");
+
+  uint max = 1000, n = 0, m = 0, can_realloc = 0;
+  void *ptr[max];
+  struct mempool_state *state[max];
+  uint len[max], num[max], align[max];
+  struct mempool *mp = mp_new(128), mp_static;
+
+  for (uint i = 0; i < 5000; i++)
+    {
+      for (uint j = 0; j < n; j++)
+	check(ptr[j], len[j], j, align[j]);
+#if 0
+      DBG("free_small=%u free_big=%u idx=%u chunk_size=%u last_big=%p", mp->state.free[0], mp->state.free[1], mp->idx, mp->chunk_size, mp->last_big);
+      for (struct mempool_chunk *ch = mp->state.last[0]; ch; ch = ch->next)
+	DBG("small %p %p %p %d", (byte *)ch - ch->size, ch, ch + 1, ch->size);
+      for (struct mempool_chunk *ch = mp->state.last[1]; ch; ch = ch->next)
+	DBG("big %p %p %p %d", (byte *)ch - ch->size, ch, ch + 1, ch->size);
+#endif
+      int r = random_max(100);
+      if ((r -= 1) < 0)
+        {
+	  DBG("flush");
+	  mp_flush(mp);
+	  n = m = 0;
+	}
+      else if ((r -= 1) < 0)
+        {
+	  DBG("delete & new");
+	  mp_delete(mp);
+	  if (random_max(2))
+	    mp = mp_new(random_max(0x1000) + 1);
+	  else
+	    mp = &mp_static, mp_init(mp, random_max(512) + 1);
+	  n = m = 0;
+	}
+      else if (n < max && (r -= 30) < 0)
+        {
+	  len[n] = random_max(0x2000);
+	  DBG("alloc(%u)", len[n]);
+	  align[n] = random_max(2) ? CPU_STRUCT_ALIGN : 1;
+	  ptr[n] = (align[n] == 1) ? mp_alloc_fast_noalign(mp, len[n]) : mp_alloc_fast(mp, len[n]);
+	  DBG(" -> (%p)", ptr[n]);
+	  fill(ptr[n], len[n], n);
+	  n++;
+	  can_realloc = 1;
+	}
+      else if (n < max && (r -= 20) < 0)
+        {
+	  len[n] = random_max(0x2000);
+	  DBG("start(%u)", len[n]);
+	  align[n] = random_max(2) ? CPU_STRUCT_ALIGN : 1;
+	  ptr[n] = (align[n] == 1) ? mp_start_fast_noalign(mp, len[n]) : mp_start_fast(mp, len[n]);
+	  DBG(" -> (%p)", ptr[n]);
+	  fill(ptr[n], len[n], n);
+	  n++;
+	  can_realloc = 1;
+	  goto grow;
+	}
+      else if (can_realloc && n && (r -= 10) < 0)
+        {
+	  if (mp_open(mp, ptr[n - 1]) != len[n - 1])
+	    ASSERT(0);
+grow:
+	  {
+	    uint k = n - 1;
+	    for (uint i = random_max(4); i--; )
+	      {
+	        uint l = len[k];
+	        len[k] = random_max(0x2000);
+	        DBG("grow(%u)", len[k]);
+	        ptr[k] = mp_grow(mp, len[k]);
+	        DBG(" -> (%p)", ptr[k]);
+	        check(ptr[k], MIN(l, len[k]), k, align[k]);
+	        fill(ptr[k], len[k], k);
+	      }
+	    mp_end(mp, ptr[k] + len[k]);
+	  }
+	}
+      else if (can_realloc && n && (r -= 20) < 0)
+        {
+	  uint i = n - 1, l = len[i];
+	  DBG("realloc(%p, %u)", ptr[i], len[i]);
+	  ptr[i] = mp_realloc(mp, ptr[i], len[i] = random_max(0x2000));
+	  DBG(" -> (%p, %u)", ptr[i], len[i]);
+	  check(ptr[i],  MIN(len[i], l), i, align[i]);
+	  fill(ptr[i], len[i], i);
+	}
+      else if (m < max && (r -= 5) < 0)
+        {
+	  DBG("push(%u)", m);
+	  num[m] = n;
+	  state[m++] = mp_push(mp);
+	  can_realloc = 0;
+	}
+      else if (m && (r -= 2) < 0)
+        {
+	  m--;
+	  DBG("pop(%u)", m);
+	  mp_pop(mp);
+	  n = num[m];
+	  can_realloc = 0;
+	}
+      else if (m && (r -= 1) < 0)
+        {
+	  uint i = random_max(m);
+	  DBG("restore(%u)", i);
+	  mp_restore(mp, state[i]);
+	  n = num[m = i];
+	  can_realloc = 0;
+	}
+      else if (can_realloc && n && (r -= 5) < 0)
+        ASSERT(mp_size(mp, ptr[n - 1]) == len[n - 1]);
+      else
+	{
+	  struct mempool_stats stats;
+	  mp_stats(mp, &stats);
+	}
+    }
+
+  mp_delete(mp);
+  return 0;
+}
+
+#endif
diff --git a/contrib/ucw/mempool.h b/contrib/ucw/mempool.h
new file mode 100644
index 0000000..0315138
--- /dev/null
+++ b/contrib/ucw/mempool.h
@@ -0,0 +1,572 @@
+/*
+ *	UCW Library -- Memory Pools
+ *
+ *	(c) 1997--2015 Martin Mares <mj@ucw.cz>
+ *	(c) 2007 Pavel Charvat <pchar@ucw.cz>
+ *	SPDX-License-Identifier: LGPL-2.1-or-later
+ *	Source: https://www.ucw.cz/libucw/
+ */
+
+#ifndef _UCW_POOLS_H
+#define _UCW_POOLS_H
+
+#include "lib/defines.h"
+#include <ucw/alloc.h>
+#include <ucw/config.h>
+#include <ucw/lib.h>
+#include <string.h>
+
+#ifdef CONFIG_UCW_CLEAN_ABI
+#define mp_alloc ucw_mp_alloc
+#define mp_alloc_internal ucw_mp_alloc_internal
+#define mp_alloc_noalign ucw_mp_alloc_noalign
+#define mp_alloc_zero ucw_mp_alloc_zero
+#define mp_delete ucw_mp_delete
+#define mp_flush ucw_mp_flush
+#define mp_grow_internal ucw_mp_grow_internal
+#define mp_init ucw_mp_init
+#define mp_memdup ucw_mp_memdup
+#define mp_multicat ucw_mp_multicat
+#define mp_new ucw_mp_new
+#define mp_open ucw_mp_open
+#define mp_pop ucw_mp_pop
+#define mp_printf ucw_mp_printf
+#define mp_printf_append ucw_mp_printf_append
+#define mp_push ucw_mp_push
+#define mp_realloc ucw_mp_realloc
+#define mp_realloc_zero ucw_mp_realloc_zero
+#define mp_restore ucw_mp_restore
+#define mp_shrink ucw_mp_shrink
+#define mp_spread_internal ucw_mp_spread_internal
+#define mp_start ucw_mp_start
+#define mp_start_internal ucw_mp_start_internal
+#define mp_start_noalign ucw_mp_start_noalign
+#define mp_stats ucw_mp_stats
+#define mp_str_from_mem ucw_mp_str_from_mem
+#define mp_strdup ucw_mp_strdup
+#define mp_strjoin ucw_mp_strjoin
+#define mp_total_size ucw_mp_total_size
+#define mp_vprintf ucw_mp_vprintf
+#define mp_vprintf_append ucw_mp_vprintf_append
+#endif
+
+/***
+ * [[defs]]
+ * Definitions
+ * -----------
+ ***/
+
+/**
+ * Memory pool state (see @mp_push(), ...).
+ * You should use this one as an opaque handle only, the insides are internal.
+ **/
+struct mempool_state {
+  size_t free[2];
+  void *last[2];
+  struct mempool_state *next;
+};
+
+/**
+ * Memory pool.
+ * You should use this one as an opaque handle only, the insides are internal.
+ **/
+struct mempool {
+  struct ucw_allocator allocator;	// This must be the first element
+  struct mempool_state state;
+  void *unused, *last_big;
+  size_t chunk_size, threshold;
+  uint idx;
+  u64 total_size;
+};
+
+struct mempool_stats {			/** Mempool statistics. See @mp_stats(). **/
+  u64 total_size;			/* Real allocated size in bytes */
+  u64 used_size;			/* Estimated size allocated from mempool to application */
+  uint chain_count[3];			/* Number of allocated chunks in small/big/unused chains */
+  u64 chain_size[3];			/* Size of allocated chunks in small/big/unused chains */
+};
+
+/***
+ * [[basic]]
+ * Basic manipulation
+ * ------------------
+ ***/
+
+/**
+ * Initialize a given mempool structure.
+ * @chunk_size must be in the interval `[1, SIZE_MAX / 2]`.
+ * It will allocate memory by this large chunks and take
+ * memory to satisfy requests from them.
+ *
+ * Memory pools can be treated as <<trans:respools,resources>>, see <<trans:res_mempool()>>.
+ **/
+KR_EXPORT
+void mp_init(struct mempool *pool, size_t chunk_size);
+
+/**
+ * Allocate and initialize a new memory pool.
+ * See @mp_init() for @chunk_size limitations.
+ *
+ * The new mempool structure is allocated on the new mempool.
+ *
+ * Memory pools can be treated as <<trans:respools,resources>>, see <<trans:res_mempool()>>.
+ **/
+KR_EXPORT
+struct mempool *mp_new(size_t chunk_size);
+
+/**
+ * Cleanup mempool initialized by mp_init or mp_new.
+ * Frees all the memory allocated by this mempool and,
+ * if created by @mp_new(), the @pool itself.
+ **/
+KR_EXPORT
+void mp_delete(struct mempool *pool);
+
+/**
+ * Frees all data on a memory pool, but leaves it working.
+ * It can keep some of the chunks allocated to serve
+ * further allocation requests. Leaves the @pool alive,
+ * even if it was created with @mp_new().
+ **/
+KR_EXPORT
+void mp_flush(struct mempool *pool);
+
+/**
+ * Compute some statistics for debug purposes.
+ * See the definition of the <<struct_mempool_stats,mempool_stats structure>>.
+ * This function scans the chunk list, so it can be slow. If you are interested
+ * in total memory consumption only, mp_total_size() is faster.
+ **/
+void mp_stats(struct mempool *pool, struct mempool_stats *stats);
+
+/**
+ * Return how many bytes were allocated by the pool, including unused parts
+ * of chunks. This function runs in constant time.
+ **/
+u64 mp_total_size(struct mempool *pool);
+
+/**
+ * Release unused chunks of memory reserved for further allocation
+ * requests, but stop if mp_total_size() would drop below @min_total_size.
+ **/
+void mp_shrink(struct mempool *pool, u64 min_total_size);
+
+/***
+ * [[alloc]]
+ * Allocation routines
+ * -------------------
+ ***/
+
+/* For internal use only, do not call directly */
+void *mp_alloc_internal(struct mempool *pool, size_t size) LIKE_MALLOC;
+
+/**
+ * The function allocates new @size bytes on a given memory pool.
+ * If the @size is zero, the resulting pointer is undefined,
+ * but it may be safely reallocated or used as the parameter
+ * to other functions below.
+ *
+ * The resulting pointer is always aligned to a multiple of
+ * `CPU_STRUCT_ALIGN` bytes and this condition remains true also
+ * after future reallocations.
+ **/
+KR_EXPORT
+void *mp_alloc(struct mempool *pool, size_t size);
+
+/**
+ * The same as @mp_alloc(), but the result may be unaligned.
+ **/
+void *mp_alloc_noalign(struct mempool *pool, size_t size);
+
+/**
+ * The same as @mp_alloc(), but fills the newly allocated memory with zeroes.
+ **/
+void *mp_alloc_zero(struct mempool *pool, size_t size);
+
+/**
+ * Inlined version of @mp_alloc().
+ **/
+static inline void *mp_alloc_fast(struct mempool *pool, size_t size)
+{
+  size_t avail = pool->state.free[0] & ~(size_t)(CPU_STRUCT_ALIGN - 1);
+  if (size <= avail)
+    {
+      pool->state.free[0] = avail - size;
+      return (byte *)pool->state.last[0] - avail;
+    }
+  else
+    return mp_alloc_internal(pool, size);
+}
+
+/**
+ * Inlined version of @mp_alloc_noalign().
+ **/
+static inline void *mp_alloc_fast_noalign(struct mempool *pool, size_t size)
+{
+  if (size <= pool->state.free[0])
+    {
+      void *ptr = (byte *)pool->state.last[0] - pool->state.free[0];
+      pool->state.free[0] -= size;
+      return ptr;
+    }
+  else
+    return mp_alloc_internal(pool, size);
+}
+
+/**
+ * Return a generic allocator representing the given mempool.
+ **/
+static inline struct ucw_allocator *mp_get_allocator(struct mempool *mp)
+{
+  return &mp->allocator;
+}
+
+/***
+ * [[gbuf]]
+ * Growing buffers
+ * ---------------
+ *
+ * You do not need to know, how a buffer will need to be large,
+ * you can grow it incrementally to needed size. You can grow only
+ * one buffer at a time on a given mempool.
+ *
+ * Similar functionality is provided by <<growbuf:,growing buffers>> module.
+ ***/
+
+/* For internal use only, do not call directly */
+void *mp_start_internal(struct mempool *pool, size_t size) LIKE_MALLOC;
+void *mp_grow_internal(struct mempool *pool, size_t size);
+void *mp_spread_internal(struct mempool *pool, void *p, size_t size);
+
+static inline uint mp_idx(struct mempool *pool, void *ptr)
+{
+  return ptr == pool->last_big;
+}
+
+/**
+ * Open a new growing buffer (at least @size bytes long).
+ * If the @size is zero, the resulting pointer is undefined,
+ * but it may be safely reallocated or used as the parameter
+ * to other functions below.
+ *
+ * The resulting pointer is always aligned to a multiple of
+ * `CPU_STRUCT_ALIGN` bytes and this condition remains true also
+ * after future reallocations. There is an unaligned version as well.
+ *
+ * Keep in mind that you can't make any other pool allocations
+ * before you "close" the growing buffer with @mp_end().
+ */
+void *mp_start(struct mempool *pool, size_t size);
+void *mp_start_noalign(struct mempool *pool, size_t size);
+
+/**
+ * Inlined version of @mp_start().
+ **/
+static inline void *mp_start_fast(struct mempool *pool, size_t size)
+{
+  size_t avail = pool->state.free[0] & ~(size_t)(CPU_STRUCT_ALIGN - 1);
+  if (size <= avail)
+    {
+      pool->idx = 0;
+      pool->state.free[0] = avail;
+      return (byte *)pool->state.last[0] - avail;
+    }
+  else
+    return mp_start_internal(pool, size);
+}
+
+/**
+ * Inlined version of @mp_start_noalign().
+ **/
+static inline void *mp_start_fast_noalign(struct mempool *pool, size_t size)
+{
+  if (size <= pool->state.free[0])
+    {
+      pool->idx = 0;
+      return (byte *)pool->state.last[0] - pool->state.free[0];
+    }
+  else
+    return mp_start_internal(pool, size);
+}
+
+/**
+ * Return start pointer of the growing buffer allocated by latest @mp_start() or a similar function.
+ **/
+static inline void *mp_ptr(struct mempool *pool)
+{
+  return (byte *)pool->state.last[pool->idx] - pool->state.free[pool->idx];
+}
+
+/**
+ * Return the number of bytes available for extending the growing buffer.
+ * (Before a reallocation will be needed).
+ **/
+static inline size_t mp_avail(struct mempool *pool)
+{
+  return pool->state.free[pool->idx];
+}
+
+/**
+ * Grow the buffer allocated by @mp_start() to be at least @size bytes long
+ * (@size may be less than @mp_avail(), even zero). Reallocated buffer may
+ * change its starting position. The content will be unchanged to the minimum
+ * of the old and new sizes; newly allocated memory will be uninitialized.
+ * Multiple calls to mp_grow() have amortized linear cost wrt. the maximum value of @size. */
+static inline void *mp_grow(struct mempool *pool, size_t size)
+{
+  return (size <= mp_avail(pool)) ? mp_ptr(pool) : mp_grow_internal(pool, size);
+}
+
+/**
+ * Grow the buffer by at least one byte -- equivalent to <<mp_grow(),`mp_grow`>>`(@pool, @mp_avail(pool) + 1)`.
+ **/
+static inline void *mp_expand(struct mempool *pool)
+{
+  return mp_grow_internal(pool, mp_avail(pool) + 1);
+}
+
+/**
+ * Ensure that there is at least @size bytes free after @p,
+ * if not, reallocate and adjust @p.
+ **/
+static inline void *mp_spread(struct mempool *pool, void *p, size_t size)
+{
+  return (((size_t)((byte *)pool->state.last[pool->idx] - (byte *)p) >= size) ? p : mp_spread_internal(pool, p, size));
+}
+
+/**
+ * Append a character to the growing buffer. Called with @p pointing after
+ * the last byte in the buffer, returns a pointer after the last byte
+ * of the new (possibly reallocated) buffer.
+ **/
+static inline char *mp_append_char(struct mempool *pool, char *p, uint c)
+{
+  p = mp_spread(pool, p, 1);
+  *p++ = c;
+  return p;
+}
+
+/**
+ * Append a memory block to the growing buffer. Called with @p pointing after
+ * the last byte in the buffer, returns a pointer after the last byte
+ * of the new (possibly reallocated) buffer.
+ **/
+static inline void *mp_append_block(struct mempool *pool, void *p, const void *block, size_t size)
+{
+  char *q = mp_spread(pool, p, size);
+  memcpy(q, block, size);
+  return q + size;
+}
+
+/**
+ * Append a string to the growing buffer. Called with @p pointing after
+ * the last byte in the buffer, returns a pointer after the last byte
+ * of the new (possibly reallocated) buffer.
+ **/
+static inline void *mp_append_string(struct mempool *pool, void *p, const char *str)
+{
+  return mp_append_block(pool, p, str, strlen(str));
+}
+
+/**
+ * Close the growing buffer. The @end must point just behind the data, you want to keep
+ * allocated (so it can be in the interval `[@mp_ptr(@pool), @mp_ptr(@pool) + @mp_avail(@pool)]`).
+ * Returns a pointer to the beginning of the just closed block.
+ **/
+static inline void *mp_end(struct mempool *pool, void *end)
+{
+  void *p = mp_ptr(pool);
+  pool->state.free[pool->idx] = (byte *)pool->state.last[pool->idx] - (byte *)end;
+  return p;
+}
+
+/**
+ * Close the growing buffer as a string. That is, append a zero byte and call mp_end().
+ **/
+static inline char *mp_end_string(struct mempool *pool, void *end)
+{
+  end = mp_append_char(pool, end, 0);
+  return mp_end(pool, end);
+}
+
+/**
+ * Return size in bytes of the last allocated memory block (with @mp_alloc() or @mp_end()).
+ **/
+static inline size_t mp_size(struct mempool *pool, void *ptr)
+{
+  uint idx = mp_idx(pool, ptr);
+  return ((byte *)pool->state.last[idx] - (byte *)ptr) - pool->state.free[idx];
+}
+
+/**
+ * Open the last memory block (allocated with @mp_alloc() or @mp_end())
+ * for growing and return its size in bytes. The contents and the start pointer
+ * remain unchanged. Do not forget to call @mp_end() to close it.
+ **/
+size_t mp_open(struct mempool *pool, void *ptr);
+
+/**
+ * Inlined version of @mp_open().
+ **/
+static inline size_t mp_open_fast(struct mempool *pool, void *ptr)
+{
+  pool->idx = mp_idx(pool, ptr);
+  size_t size = ((byte *)pool->state.last[pool->idx] - (byte *)ptr) - pool->state.free[pool->idx];
+  pool->state.free[pool->idx] += size;
+  return size;
+}
+
+/**
+ * Reallocate the last memory block (allocated with @mp_alloc() or @mp_end())
+ * to the new @size. Behavior is similar to @mp_grow(), but the resulting
+ * block is closed.
+ **/
+void *mp_realloc(struct mempool *pool, void *ptr, size_t size);
+
+/**
+ * The same as @mp_realloc(), but fills the additional bytes (if any) with zeroes.
+ **/
+void *mp_realloc_zero(struct mempool *pool, void *ptr, size_t size);
+
+/**
+ * Inlined version of @mp_realloc().
+ **/
+static inline void *mp_realloc_fast(struct mempool *pool, void *ptr, size_t size)
+{
+  mp_open_fast(pool, ptr);
+  ptr = mp_grow(pool, size);
+  mp_end(pool, (byte *)ptr + size);
+  return ptr;
+}
+
+/***
+ * [[store]]
+ * Storing and restoring state
+ * ---------------------------
+ *
+ * Mempools can remember history of what was allocated and return back
+ * in time.
+ ***/
+
+/**
+ * Save the current state of a memory pool.
+ * Do not call this function with an opened growing buffer.
+ **/
+static inline void mp_save(struct mempool *pool, struct mempool_state *state)
+{
+  *state = pool->state;
+  pool->state.next = state;
+}
+
+/**
+ * Save the current state to a newly allocated mempool_state structure.
+ * Do not call this function with an opened growing buffer.
+ **/
+struct mempool_state *mp_push(struct mempool *pool);
+
+/**
+ * Restore the state saved by @mp_save() or @mp_push() and free all
+ * data allocated after that point (including the state structure itself).
+ * You can't reallocate the last memory block from the saved state.
+ **/
+void mp_restore(struct mempool *pool, struct mempool_state *state);
+
+/**
+ * Inlined version of @mp_restore().
+ **/
+static inline void mp_restore_fast(struct mempool *pool, struct mempool_state *state)
+{
+  if (pool->state.last[0] != state->last[0] || pool->state.last[1] != state->last[1])
+    mp_restore(pool, state);
+  else
+    {
+      pool->state = *state;
+      pool->last_big = &pool->last_big;
+    }
+}
+
+/**
+ * Restore the state saved by the last call to @mp_push().
+ * @mp_pop() and @mp_push() works as a stack so you can push more states safely.
+ **/
+void mp_pop(struct mempool *pool);
+
+
+/***
+ * [[string]]
+ * String operations
+ * -----------------
+ ***/
+
+char *mp_strdup(struct mempool *, const char *) LIKE_MALLOC;		/** Makes a copy of a string on a mempool. Returns NULL for NULL string. **/
+void *mp_memdup(struct mempool *, const void *, size_t) LIKE_MALLOC;	/** Makes a copy of a memory block on a mempool. **/
+/**
+ * Concatenates all passed strings. The last parameter must be NULL.
+ * This will concatenate two strings:
+ *
+ *   char *message = mp_multicat(pool, "hello ", "world", NULL);
+ **/
+char *mp_multicat(struct mempool *, ...) LIKE_MALLOC SENTINEL_CHECK;
+/**
+ * Concatenates two strings and stores result on @mp.
+ */
+static inline char *LIKE_MALLOC mp_strcat(struct mempool *mp, const char *x, const char *y)
+{
+  return mp_multicat(mp, x, y, NULL);
+}
+/**
+ * Join strings and place @sep between each two neighboring.
+ * @p is the mempool to provide memory, @a is array of strings and @n
+ * tells how many there is of them.
+ **/
+char *mp_strjoin(struct mempool *p, char **a, uint n, uint sep) LIKE_MALLOC;
+/**
+ * Convert memory block to a string. Makes a copy of the given memory block
+ * in the mempool @p, adding an extra terminating zero byte at the end.
+ **/
+char *mp_str_from_mem(struct mempool *p, const void *mem, size_t len) LIKE_MALLOC;
+
+
+/***
+ * [[format]]
+ * Formatted output
+ * ---------------
+ ***/
+
+/**
+ * printf() into a in-memory string, allocated on the memory pool.
+ **/
+KR_EXPORT
+char *mp_printf(struct mempool *mp, const char *fmt, ...) FORMAT_CHECK(printf,2,3) LIKE_MALLOC;
+/**
+ * Like @mp_printf(), but uses `va_list` for parameters.
+ **/
+char *mp_vprintf(struct mempool *mp, const char *fmt, va_list args) LIKE_MALLOC;
+/**
+ * Like @mp_printf(), but it appends the data at the end of string
+ * pointed to by @ptr. The string is @mp_open()ed, so you have to
+ * provide something that can be.
+ *
+ * Returns pointer to the beginning of the string (the pointer may have
+ * changed due to reallocation).
+ *
+ * In some versions of LibUCW, this function was called mp_append_printf(). However,
+ * this name turned out to be confusing -- unlike other appending functions, this one is
+ * not called on an opened growing buffer. The old name will be preserved for backward
+ * compatibility for the time being.
+ **/
+KR_EXPORT
+char *mp_printf_append(struct mempool *mp, char *ptr, const char *fmt, ...) FORMAT_CHECK(printf,3,4);
+#define mp_append_printf mp_printf_append
+/**
+ * Like @mp_printf_append(), but uses `va_list` for parameters.
+ *
+ * In some versions of LibUCW, this function was called mp_append_vprintf(). However,
+ * this name turned out to be confusing -- unlike other appending functions, this one is
+ * not called on an opened growing buffer. The old name will be preserved for backward
+ * compatibility for the time being.
+ **/
+char *mp_vprintf_append(struct mempool *mp, char *ptr, const char *fmt, va_list args);
+#define mp_append_vprintf mp_vprintf_append
+
+#endif