diff --git a/contrib/ip6range/Makefile b/contrib/ip6range/Makefile
new file mode 100644
index 0000000..55849b6
--- /dev/null
+++ b/contrib/ip6range/Makefile
@@ -0,0 +1,13 @@
+CC       = gcc
+OPTIMIZE = -O3
+LDFLAGS  = -s
+
+OBJS     = ip6range
+
+all: $(OBJS)
+
+%: %.c
+	$(CC) $(LDFLAGS) $(OPTIMIZE) -o $@ $^
+
+clean:
+	rm -f $(OBJS) *.o *.a *~
diff --git a/contrib/ip6range/ip6range.c b/contrib/ip6range/ip6range.c
new file mode 100644
index 0000000..293e7d2
--- /dev/null
+++ b/contrib/ip6range/ip6range.c
@@ -0,0 +1,396 @@
+/*
+ * network range to IP+mask converter
+ *
+ * Copyright 2011-2012 Willy Tarreau <w@1wt.eu>
+ *
+ * This program reads lines starting by two IP addresses and outputs them with
+ * the two IP addresses replaced by a netmask covering the range between these
+ * IPs (inclusive). When multiple ranges are needed, as many lines are emitted.
+ * The IP addresses may be delimited by spaces, tabs or commas. Quotes are
+ * stripped, and lines beginning with a sharp character ('#') are ignored. The
+ * IP addresses may be either in the dotted format or represented as a 32-bit
+ * integer value in network byte order.
+ *
+ * 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
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <arpa/inet.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define MAXLINE 1024
+
+static inline void in6_bswap(struct in6_addr *a)
+{
+	a->in6_u.u6_addr32[0] = ntohl(a->in6_u.u6_addr32[0]);
+	a->in6_u.u6_addr32[1] = ntohl(a->in6_u.u6_addr32[1]);
+	a->in6_u.u6_addr32[2] = ntohl(a->in6_u.u6_addr32[2]);
+	a->in6_u.u6_addr32[3] = ntohl(a->in6_u.u6_addr32[3]);
+}
+
+/* returns a string version of an IPv6 address in host order */
+static const char *get_ipv6_addr(struct in6_addr *addr)
+{
+	struct in6_addr a;
+	static char out[INET6_ADDRSTRLEN + 1];
+
+	memcpy(&a, addr, sizeof(struct in6_addr));
+	in6_bswap(&a);
+	return inet_ntop(AF_INET6, &a, out, INET6_ADDRSTRLEN + 1);
+}
+
+static const char *get_addr(struct in6_addr *addr)
+{
+	static char out[50];
+	snprintf(out, 50, "%08x:%08x:%08x:%08x",
+	         addr->in6_u.u6_addr32[0],
+	         addr->in6_u.u6_addr32[1],
+	         addr->in6_u.u6_addr32[2],
+	         addr->in6_u.u6_addr32[3]);
+	return out;
+}
+
+/* a <= b */
+static inline int a_le_b(struct in6_addr *a, struct in6_addr *b)
+{
+	if (a->in6_u.u6_addr32[0] < b->in6_u.u6_addr32[0]) return 1;
+	if (a->in6_u.u6_addr32[0] > b->in6_u.u6_addr32[0]) return 0;
+	if (a->in6_u.u6_addr32[1] < b->in6_u.u6_addr32[1]) return 1;
+	if (a->in6_u.u6_addr32[1] > b->in6_u.u6_addr32[1]) return 0;
+	if (a->in6_u.u6_addr32[2] < b->in6_u.u6_addr32[2]) return 1;
+	if (a->in6_u.u6_addr32[2] > b->in6_u.u6_addr32[2]) return 0;
+	if (a->in6_u.u6_addr32[3] < b->in6_u.u6_addr32[3]) return 1;
+	if (a->in6_u.u6_addr32[3] > b->in6_u.u6_addr32[3]) return 0;
+	return 1;
+}
+
+/* a == b */
+static inline int a_eq_b(struct in6_addr *a, struct in6_addr *b)
+{
+	if (a->in6_u.u6_addr32[0] != b->in6_u.u6_addr32[0]) return 0;
+	if (a->in6_u.u6_addr32[1] != b->in6_u.u6_addr32[1]) return 0;
+	if (a->in6_u.u6_addr32[2] != b->in6_u.u6_addr32[2]) return 0;
+	if (a->in6_u.u6_addr32[3] != b->in6_u.u6_addr32[3]) return 0;
+	return 1;
+}
+
+/* a > b */
+static inline int a_gt_b(struct in6_addr *a, struct in6_addr *b)
+{
+	if (a->in6_u.u6_addr32[0] > b->in6_u.u6_addr32[0]) return 1;
+	if (a->in6_u.u6_addr32[0] < b->in6_u.u6_addr32[0]) return 0;
+	if (a->in6_u.u6_addr32[1] > b->in6_u.u6_addr32[1]) return 1;
+	if (a->in6_u.u6_addr32[1] < b->in6_u.u6_addr32[1]) return 0;
+	if (a->in6_u.u6_addr32[2] > b->in6_u.u6_addr32[2]) return 1;
+	if (a->in6_u.u6_addr32[2] < b->in6_u.u6_addr32[2]) return 0;
+	if (a->in6_u.u6_addr32[3] > b->in6_u.u6_addr32[3]) return 1;
+	if (a->in6_u.u6_addr32[3] < b->in6_u.u6_addr32[3]) return 0;
+	return 0;
+}
+
+/* ( 1 << m ) - 1 -> r */
+static inline struct in6_addr *hmask(unsigned int b, struct in6_addr *r)
+{
+
+	if (b < 32) {
+		r->in6_u.u6_addr32[3] = (1 << b) - 1;
+		r->in6_u.u6_addr32[2] = 0;
+		r->in6_u.u6_addr32[1] = 0;
+		r->in6_u.u6_addr32[0] = 0;
+	}
+	else if (b < 64) {
+		r->in6_u.u6_addr32[3] = 0xffffffff;
+		r->in6_u.u6_addr32[2] = (1 << (b - 32)) - 1;
+		r->in6_u.u6_addr32[1] = 0;
+		r->in6_u.u6_addr32[0] = 0;
+	}
+	else if (b < 96) {
+		r->in6_u.u6_addr32[3] = 0xffffffff;
+		r->in6_u.u6_addr32[2] = 0xffffffff;
+		r->in6_u.u6_addr32[1] = (1 << (b - 64)) - 1;
+		r->in6_u.u6_addr32[0] = 0;
+	}
+	else if (b < 128) {
+		r->in6_u.u6_addr32[3] = 0xffffffff;
+		r->in6_u.u6_addr32[2] = 0xffffffff;
+		r->in6_u.u6_addr32[1] = 0xffffffff;
+		r->in6_u.u6_addr32[0] = (1 << (b - 96)) - 1;
+	}
+	else {
+		r->in6_u.u6_addr32[3] = 0xffffffff;
+		r->in6_u.u6_addr32[2] = 0xffffffff;
+		r->in6_u.u6_addr32[1] = 0xffffffff;
+		r->in6_u.u6_addr32[0] = 0xffffffff;
+	}
+	return r;
+}
+
+/* 1 << b -> r */
+static inline struct in6_addr *one_ls_b(unsigned int b, struct in6_addr *r)
+{
+	if (b < 32) {
+		r->in6_u.u6_addr32[3] = 1 << b;
+		r->in6_u.u6_addr32[2] = 0;
+		r->in6_u.u6_addr32[1] = 0;
+		r->in6_u.u6_addr32[0] = 0;
+	}
+	else if (b < 64) {
+		r->in6_u.u6_addr32[3] = 0;
+		r->in6_u.u6_addr32[2] = 1 << (b - 32);
+		r->in6_u.u6_addr32[1] = 0;
+		r->in6_u.u6_addr32[0] = 0;
+	}
+	else if (b < 96) {
+		r->in6_u.u6_addr32[3] = 0;
+		r->in6_u.u6_addr32[2] = 0;
+		r->in6_u.u6_addr32[1] = 1 << (b - 64);
+		r->in6_u.u6_addr32[0] = 0;
+	}
+	else if (b < 128) {
+		r->in6_u.u6_addr32[3] = 0;
+		r->in6_u.u6_addr32[2] = 0;
+		r->in6_u.u6_addr32[1] = 0;
+		r->in6_u.u6_addr32[0] = 1 << (b - 96);
+	}
+	else {
+		r->in6_u.u6_addr32[3] = 0;
+		r->in6_u.u6_addr32[2] = 0;
+		r->in6_u.u6_addr32[1] = 0;
+		r->in6_u.u6_addr32[0] = 0;
+	}
+	return r;
+}
+
+/* a + b -> r */
+static inline struct in6_addr *a_plus_b(struct in6_addr *a, struct in6_addr *b, struct in6_addr *r)
+{
+	unsigned long long int c = 0;
+	int i;
+
+	for (i=3; i>=0; i--) {
+		c = (unsigned long long int)a->in6_u.u6_addr32[i] +
+		    (unsigned long long int)b->in6_u.u6_addr32[i] + c;
+		r->in6_u.u6_addr32[i] = c;
+		c >>= 32;
+	}
+
+	return r;
+}
+
+/* a - b -> r */
+static inline struct in6_addr *a_minus_b(struct in6_addr *a, struct in6_addr *b, struct in6_addr *r)
+{
+	signed long long int c = 0;
+	signed long long int d;
+	int i;
+
+	/* Check sign. Return 0xff..ff (-1) if the result is less than 0. */
+	if (a_gt_b(b, a)) {
+		r->in6_u.u6_addr32[3] = 0xffffffff;
+		r->in6_u.u6_addr32[2] = 0xffffffff;
+		r->in6_u.u6_addr32[1] = 0xffffffff;
+		r->in6_u.u6_addr32[0] = 0xffffffff;
+		return r;
+	}
+
+	for (i=3; i>=0; i--) {
+		d = (unsigned long long int)b->in6_u.u6_addr32[i] + c;
+		c = (unsigned long long int)a->in6_u.u6_addr32[i];
+		if (c < d)
+			c += 0x100000000ULL;
+		c -= d;
+		r->in6_u.u6_addr32[i] = c;
+		c >>= 32;
+	}
+
+	return r;
+}
+
+/* a & b -> r */
+static inline struct in6_addr *a_and_b(struct in6_addr *a, struct in6_addr *b, struct in6_addr *r)
+{
+	r->in6_u.u6_addr32[0] = a->in6_u.u6_addr32[0] & b->in6_u.u6_addr32[0];
+	r->in6_u.u6_addr32[1] = a->in6_u.u6_addr32[1] & b->in6_u.u6_addr32[1];
+	r->in6_u.u6_addr32[2] = a->in6_u.u6_addr32[2] & b->in6_u.u6_addr32[2];
+	r->in6_u.u6_addr32[3] = a->in6_u.u6_addr32[3] & b->in6_u.u6_addr32[3];
+	return r;
+}
+
+/* a != 0 */
+int is_set(struct in6_addr *a)
+{
+	return a->in6_u.u6_addr32[0] ||
+	       a->in6_u.u6_addr32[1] ||
+	       a->in6_u.u6_addr32[2] ||
+	       a->in6_u.u6_addr32[3];
+}
+
+/* 1 */
+static struct in6_addr one = { .in6_u.u6_addr32 = {0, 0, 0, 1} };
+
+/* print all networks present between address <low> and address <high> in
+ * cidr format, followed by <eol>.
+ */
+static void convert_range(struct in6_addr *low, struct in6_addr *high, const char *eol, const char *pfx)
+{
+	int bit;
+	struct in6_addr r0;
+	struct in6_addr r1;
+
+	if (a_eq_b(low, high)) {
+		/* single value */
+		printf("%s%s%s%s\n", pfx?pfx:"", pfx?" ":"", get_ipv6_addr(low), eol);
+		return;
+	}
+	else if (a_gt_b(low, high)) {
+		struct in6_addr *swap = low;
+		low = high;
+		high = swap;
+	}
+
+	if (a_eq_b(low, a_plus_b(high, &one, &r0))) {
+		/* full range */
+		printf("%s%s::/0%s\n", pfx?pfx:"", pfx?" ":"", eol);
+		return;
+	}
+	//printf("low=%08x high=%08x\n", low, high);
+
+	bit = 0;
+	while (bit < 128 && a_le_b(a_plus_b(low, hmask(bit, &r0), &r0), high)) {
+
+		/* enlarge mask */
+		if (is_set(a_and_b(low, one_ls_b(bit, &r0), &r0))) {
+			/* can't aggregate anymore, dump and retry from the same bit */
+			printf("%s%s%s/%d%s\n", pfx?pfx:"", pfx?" ":"", get_ipv6_addr(low), 128-bit, eol);
+			a_plus_b(low, one_ls_b(bit, &r0), low);
+		}
+		else {
+			/* try to enlarge the mask as much as possible first */
+			bit++;
+			//printf("  ++bit=%d\n", bit);
+		}
+	}
+	//printf("stopped 1 at low=%08x, bit=%d\n", low, bit);
+
+	bit = 127;
+	while (bit >= 0 && is_set(a_plus_b(a_minus_b(high, low, &r0), &one, &r0))) {
+
+		/* shrink mask */
+		if (is_set(a_and_b(a_plus_b(a_minus_b(high, low, &r0), &one, &r0), one_ls_b(bit, &r1), &r1))) {
+			/* large bit accepted, dump and go on from the same bit */
+			//printf("max: %08x/%d\n", low, 32-bit);
+			printf("%s%s%s/%d%s\n", pfx?pfx:"", pfx?" ":"", get_ipv6_addr(low), 128-bit, eol);
+			a_plus_b(low, one_ls_b(bit, &r0), low);
+		}
+		else {
+			bit--;
+			//printf("  --bit=%d, low=%08x\n", bit, low);
+		}
+	}
+	//printf("stopped at low=%08x\n", low);
+}
+
+static void usage(const char *argv0)
+{
+	fprintf(stderr,
+	        "Usage: %s [<addr> ...] < iplist.csv\n"
+	        "\n"
+	        "This program reads lines starting by two IP addresses and outputs them with\n"
+	        "the two IP addresses replaced by a netmask covering the range between these\n"
+	        "IPs (inclusive). When multiple ranges are needed, as many lines are emitted.\n"
+	        "The IP addresses may be delimited by spaces, tabs or commas. Quotes are\n"
+	        "stripped, and lines beginning with a sharp character ('#') are ignored. The\n"
+	        "IP addresses may be either in the dotted format or represented as a 32-bit\n"
+	        "integer value in network byte order.\n"
+		"\n"
+		"For each optional <addr> specified, only the network it belongs to is returned,\n"
+		"prefixed with the <addr> value.\n"
+		"\n", argv0);
+}
+
+main(int argc, char **argv)
+{
+	char line[MAXLINE];
+	int l, lnum;
+	char *lb, *le, *hb, *he, *err;
+	struct in6_addr sa, da, ta;
+
+	if (argc > 1 && *argv[1] == '-') {
+		usage(argv[0]);
+		exit(1);
+	}
+
+	lnum = 0;
+	while (fgets(line, sizeof(line), stdin) != NULL) {
+		l = strlen(line);
+		if (l && line[l - 1] == '\n')
+			line[--l] = '\0';
+
+		lnum++;
+		/* look for the first field which must be the low address of a range,
+		 * in dotted IPv4 format or as an integer. spaces and commas are
+		 * considered as delimiters, quotes are removed.
+		 */
+		for (lb = line; *lb == ' ' || *lb == '\t' || *lb == ',' || *lb == '"'; lb++);
+		if (!*lb || *lb == '#')
+			continue;
+		for (le = lb + 1; *le != ' ' && *le != '\t' && *le != ',' && *le != '"' && *le; le++);
+		if (!*le)
+			continue;
+		/* we have the low address between lb(included) and le(excluded) */
+		*(le++) = 0;
+
+		for (hb = le; *hb == ' ' || *hb == '\t' || *hb == ',' || *hb == '"'; hb++);
+		if (!*hb || *hb == '#')
+			continue;
+		for (he = hb + 1; *he != ' ' && *he != '\t' && *he != ',' && *he != '"' && *he; he++);
+		if (!*he)
+			continue;
+		/* we have the high address between hb(included) and he(excluded) */
+		*(he++) = 0;
+
+		/* we want to remove a possible ending quote and a possible comma,
+		 * not more.
+		 */
+		while (*he == '"')
+			*(he++) = ' ';
+		while (*he == ',' || *he == ' ' || *he == '\t')
+			*(he++) = ' ';
+
+		/* if the trailing string is not empty, prefix it with a space */
+		if (*(he-1) == ' ')
+			he--;
+
+		if (inet_pton(AF_INET6, lb, &sa) <= 0) {
+			fprintf(stderr, "Failed to parse source address <%s> at line %d, skipping line\n", lb, lnum);
+			continue;
+		}
+
+		if (inet_pton(AF_INET6, hb, &da) <= 0) {
+			fprintf(stderr, "Failed to parse destination address <%s> at line %d, skipping line\n", hb, lnum);
+			continue;
+		}
+
+		in6_bswap(&sa);
+		in6_bswap(&da);
+
+		if (argc > 1) {
+			for (l = 1; l < argc; l++) {
+				if (inet_pton(AF_INET6, argv[l], &da) <= 0)
+					continue;
+				in6_bswap(&ta);
+				if ((a_le_b(&sa, &ta) && a_le_b(&ta, &da)) || (a_le_b(&da, &ta) && a_le_b(&ta, &sa)))
+					convert_range(&sa, &da, he, argv[l]);
+			}
+		}
+		else {
+			convert_range(&sa, &da, he, NULL);
+		}
+	}
+}