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From 75d1640b9a77c2d5843a18774880aabf38d1062b Mon Sep 17 00:00:00 2001
From: Phil Sutter <psutter@redhat.com>
Date: Fri, 17 Mar 2017 13:19:41 +0100
Subject: [PATCH] make format_host non-reentrant by default

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1422629
Upstream Status: iproute2.git commit a418e451643e7
Conflicts:
* Parts applied manually due to big differences in changed code
  between upstream and RHEL.
* Two calls in misc/ss.c converted manually.
* Drop iproute_lwtunnel hunks as we don't support it

commit a418e451643e77fe36861e53359587ba8aa41873
Author: Phil Sutter <phil@nwl.cc>
Date:   Tue Mar 22 19:35:15 2016 +0100

    make format_host non-reentrant by default

    There are only three users which require it to be reentrant, the rest is
    fine without. Instead, provide a reentrant format_host_r() for users
    which need it.

    Signed-off-by: Phil Sutter <phil@nwl.cc>
---
 bridge/fdb.c          |  4 +---
 include/utils.h       |  3 ++-
 ip/ip6tunnel.c        |  2 +-
 ip/ipaddress.c        | 13 ++++---------
 ip/ipaddrlabel.c      |  4 +---
 ip/iplink_geneve.c    |  5 ++---
 ip/iplink_vxlan.c     | 13 ++++++-------
 ip/ipmaddr.c          |  5 +----
 ip/ipneigh.c          |  4 +---
 ip/iproute.c          | 12 ++++--------
 ip/iprule.c           |  9 +++------
 ip/iptoken.c          |  4 +---
 ip/iptunnel.c         |  6 +++---
 ip/link_gre.c         |  5 ++---
 ip/link_gre6.c        |  5 ++---
 ip/link_iptnl.c       |  7 +++----
 ip/link_vti.c         |  5 ++---
 ip/link_vti6.c        |  5 ++---
 ip/tcp_metrics.c      |  4 +---
 lib/utils.c           |  9 ++++++++-
 misc/ss.c             | 11 ++++-------
 tc/m_nat.c            |  4 ++--
 23 files changed, 57 insertions(+), 86 deletions(-)

diff --git a/bridge/fdb.c b/bridge/fdb.c
index d184f7e..4b536f9 100644
--- a/bridge/fdb.c
+++ b/bridge/fdb.c
@@ -110,7 +110,6 @@ int print_fdb(const struct sockaddr_nl *who, struct nlmsghdr *n, void *arg)
 		fprintf(fp, "dev %s ", ll_index_to_name(r->ndm_ifindex));
 
 	if (tb[NDA_DST]) {
-		SPRINT_BUF(abuf);
 		int family = AF_INET;
 
 		if (RTA_PAYLOAD(tb[NDA_DST]) == sizeof(struct in6_addr))
@@ -119,8 +118,7 @@ int print_fdb(const struct sockaddr_nl *who, struct nlmsghdr *n, void *arg)
 		fprintf(fp, "dst %s ",
 			format_host(family,
 				    RTA_PAYLOAD(tb[NDA_DST]),
-				    RTA_DATA(tb[NDA_DST]),
-				    abuf, sizeof(abuf)));
+				    RTA_DATA(tb[NDA_DST])));
 	}
 
 	if (vid)
diff --git a/include/utils.h b/include/utils.h
index 9839d9d..df6ce04 100644
--- a/include/utils.h
+++ b/include/utils.h
@@ -109,8 +109,9 @@ int get_be16(__be16 *val, const char *arg, int base);
 char *hexstring_n2a(const __u8 *str, int len, char *buf, int blen);
 __u8 *hexstring_a2n(const char *str, __u8 *buf, int blen, unsigned int *len);
 
-const char *format_host(int af, int len, const void *addr,
+const char *format_host_r(int af, int len, const void *addr,
 			       char *buf, int buflen);
+const char *format_host(int af, int lne, const void *addr);
 const char *rt_addr_n2a(int af, int len, const void *addr,
 			       char *buf, int buflen);
 
diff --git a/ip/ip6tunnel.c b/ip/ip6tunnel.c
index 97c99e2..ab8603d 100644
--- a/ip/ip6tunnel.c
+++ b/ip/ip6tunnel.c
@@ -78,7 +78,7 @@ static void print_tunnel(struct ip6_tnl_parm2 *p)
 	printf("%s: %s/ipv6 remote %s local %s",
 	       p->name,
 	       tnl_strproto(p->proto),
-	       format_host(AF_INET6, 16, &p->raddr, s1, sizeof(s1)),
+	       format_host_r(AF_INET6, 16, &p->raddr, s1, sizeof(s1)),
 	       rt_addr_n2a(AF_INET6, 16, &p->laddr, s2, sizeof(s2)));
 	if (p->link) {
 		const char *n = ll_index_to_name(p->link);
diff --git a/ip/ipaddress.c b/ip/ipaddress.c
index 147bcca..5f08cde 100644
--- a/ip/ipaddress.c
+++ b/ip/ipaddress.c
@@ -776,7 +776,6 @@ int print_addrinfo(const struct sockaddr_nl *who, struct nlmsghdr *n,
 	/* Use local copy of ifa_flags to not interfere with filtering code */
 	unsigned int ifa_flags;
 	struct rtattr * rta_tb[IFA_MAX+1];
-	char abuf[256];
 	SPRINT_BUF(b1);
 
 	if (n->nlmsg_type != RTM_NEWADDR && n->nlmsg_type != RTM_DELADDR)
@@ -866,8 +865,7 @@ int print_addrinfo(const struct sockaddr_nl *who, struct nlmsghdr *n,
 	if (rta_tb[IFA_LOCAL]) {
 		fprintf(fp, "%s", format_host(ifa->ifa_family,
 					      RTA_PAYLOAD(rta_tb[IFA_LOCAL]),
-					      RTA_DATA(rta_tb[IFA_LOCAL]),
-					      abuf, sizeof(abuf)));
+					      RTA_DATA(rta_tb[IFA_LOCAL])));
 
 		if (rta_tb[IFA_ADDRESS] == NULL ||
 		    memcmp(RTA_DATA(rta_tb[IFA_ADDRESS]), RTA_DATA(rta_tb[IFA_LOCAL]),
@@ -877,8 +875,7 @@ int print_addrinfo(const struct sockaddr_nl *who, struct nlmsghdr *n,
 			fprintf(fp, " peer %s/%d ",
 				format_host(ifa->ifa_family,
 					    RTA_PAYLOAD(rta_tb[IFA_ADDRESS]),
-					    RTA_DATA(rta_tb[IFA_ADDRESS]),
-					    abuf, sizeof(abuf)),
+					    RTA_DATA(rta_tb[IFA_ADDRESS])),
 				ifa->ifa_prefixlen);
 		}
 	}
@@ -887,15 +884,13 @@ int print_addrinfo(const struct sockaddr_nl *who, struct nlmsghdr *n,
 		fprintf(fp, "brd %s ",
 			format_host(ifa->ifa_family,
 				    RTA_PAYLOAD(rta_tb[IFA_BROADCAST]),
-				    RTA_DATA(rta_tb[IFA_BROADCAST]),
-				    abuf, sizeof(abuf)));
+				    RTA_DATA(rta_tb[IFA_BROADCAST])));
 	}
 	if (rta_tb[IFA_ANYCAST]) {
 		fprintf(fp, "any %s ",
 			format_host(ifa->ifa_family,
 				    RTA_PAYLOAD(rta_tb[IFA_ANYCAST]),
-				    RTA_DATA(rta_tb[IFA_ANYCAST]),
-				    abuf, sizeof(abuf)));
+				    RTA_DATA(rta_tb[IFA_ANYCAST])));
 	}
 	fprintf(fp, "scope %s ", rtnl_rtscope_n2a(ifa->ifa_scope, b1, sizeof(b1)));
 	if (ifa_flags & IFA_F_SECONDARY) {
diff --git a/ip/ipaddrlabel.c b/ip/ipaddrlabel.c
index a0b6e6f..e834a87 100644
--- a/ip/ipaddrlabel.c
+++ b/ip/ipaddrlabel.c
@@ -61,7 +61,6 @@ int print_addrlabel(const struct sockaddr_nl *who, struct nlmsghdr *n, void *arg
 	struct ifaddrlblmsg *ifal = NLMSG_DATA(n);
 	int len = n->nlmsg_len;
 	struct rtattr *tb[IFAL_MAX+1];
-	char abuf[256];
 
 	if (n->nlmsg_type != RTM_NEWADDRLABEL && n->nlmsg_type != RTM_DELADDRLABEL)
 		return 0;
@@ -79,8 +78,7 @@ int print_addrlabel(const struct sockaddr_nl *who, struct nlmsghdr *n, void *arg
 		fprintf(fp, "prefix %s/%u ",
 			format_host(ifal->ifal_family,
 				    RTA_PAYLOAD(tb[IFAL_ADDRESS]),
-				    RTA_DATA(tb[IFAL_ADDRESS]),
-				    abuf, sizeof(abuf)),
+				    RTA_DATA(tb[IFAL_ADDRESS])),
 			ifal->ifal_prefixlen);
 	}
 
diff --git a/ip/iplink_geneve.c b/ip/iplink_geneve.c
index 905c537..2e15a1d 100644
--- a/ip/iplink_geneve.c
+++ b/ip/iplink_geneve.c
@@ -181,7 +181,6 @@ static int geneve_parse_opt(struct link_util *lu, int argc, char **argv,
 static void geneve_print_opt(struct link_util *lu, FILE *f, struct rtattr *tb[])
 {
 	__u32 vni;
-	char s1[1024];
 	__u8 tos;
 
 	if (!tb)
@@ -198,14 +197,14 @@ static void geneve_print_opt(struct link_util *lu, FILE *f, struct rtattr *tb[])
 		__be32 addr = rta_getattr_u32(tb[IFLA_GENEVE_REMOTE]);
 		if (addr)
 			fprintf(f, "remote %s ",
-				format_host(AF_INET, 4, &addr, s1, sizeof(s1)));
+				format_host(AF_INET, 4, &addr));
 	} else if (tb[IFLA_GENEVE_REMOTE6]) {
 		struct in6_addr addr;
 		memcpy(&addr, RTA_DATA(tb[IFLA_GENEVE_REMOTE6]), sizeof(struct in6_addr));
 		if (memcmp(&addr, &in6addr_any, sizeof(addr)) != 0) {
 			if (!IN6_IS_ADDR_MULTICAST(&addr))
 				fprintf(f, "remote %s ",
-					format_host(AF_INET6, sizeof(struct in6_addr), &addr, s1, sizeof(s1)));
+					format_host(AF_INET6, sizeof(struct in6_addr), &addr));
 		}
 	}
 
diff --git a/ip/iplink_vxlan.c b/ip/iplink_vxlan.c
index 015d7d9..6cae35b 100644
--- a/ip/iplink_vxlan.c
+++ b/ip/iplink_vxlan.c
@@ -282,7 +282,6 @@ static void vxlan_print_opt(struct link_util *lu, FILE *f, struct rtattr *tb[])
 	unsigned link;
 	__u8 tos;
 	__u32 maxaddr;
-	char s1[1024];
 	char s2[64];
 
 	if (!tb)
@@ -300,10 +299,10 @@ static void vxlan_print_opt(struct link_util *lu, FILE *f, struct rtattr *tb[])
 		if (addr) {
 			if (IN_MULTICAST(ntohl(addr)))
 				fprintf(f, "group %s ",
-					format_host(AF_INET, 4, &addr, s1, sizeof(s1)));
+					format_host(AF_INET, 4, &addr));
 			else
 				fprintf(f, "remote %s ",
-					format_host(AF_INET, 4, &addr, s1, sizeof(s1)));
+					format_host(AF_INET, 4, &addr));
 		}
 	} else if (tb[IFLA_VXLAN_GROUP6]) {
 		struct in6_addr addr;
@@ -311,10 +310,10 @@ static void vxlan_print_opt(struct link_util *lu, FILE *f, struct rtattr *tb[])
 		if (memcmp(&addr, &in6addr_any, sizeof(addr)) != 0) {
 			if (IN6_IS_ADDR_MULTICAST(&addr))
 				fprintf(f, "group %s ",
-					format_host(AF_INET6, sizeof(struct in6_addr), &addr, s1, sizeof(s1)));
+					format_host(AF_INET6, sizeof(struct in6_addr), &addr));
 			else
 				fprintf(f, "remote %s ",
-					format_host(AF_INET6, sizeof(struct in6_addr), &addr, s1, sizeof(s1)));
+					format_host(AF_INET6, sizeof(struct in6_addr), &addr));
 		}
 	}
 
@@ -322,13 +321,13 @@ static void vxlan_print_opt(struct link_util *lu, FILE *f, struct rtattr *tb[])
 		__be32 addr = rta_getattr_u32(tb[IFLA_VXLAN_LOCAL]);
 		if (addr)
 			fprintf(f, "local %s ",
-				format_host(AF_INET, 4, &addr, s1, sizeof(s1)));
+				format_host(AF_INET, 4, &addr));
 	} else if (tb[IFLA_VXLAN_LOCAL6]) {
 		struct in6_addr addr;
 		memcpy(&addr, RTA_DATA(tb[IFLA_VXLAN_LOCAL6]), sizeof(struct in6_addr));
 		if (memcmp(&addr, &in6addr_any, sizeof(addr)) != 0)
 			fprintf(f, "local %s ",
-				format_host(AF_INET6, sizeof(struct in6_addr), &addr, s1, sizeof(s1)));
+				format_host(AF_INET6, sizeof(struct in6_addr), &addr));
 	}
 
 	if (tb[IFLA_VXLAN_LINK] &&
diff --git a/ip/ipmaddr.c b/ip/ipmaddr.c
index a77a18f..5c3dc28 100644
--- a/ip/ipmaddr.c
+++ b/ip/ipmaddr.c
@@ -204,7 +204,6 @@ static void print_maddr(FILE *fp, struct ma_info *list)
 						    list->addr.bytelen, 0,
 						    b1, sizeof(b1)));
 	} else {
-		char abuf[256];
 		switch(list->addr.family) {
 		case AF_INET:
 			fprintf(fp, "inet  ");
@@ -218,9 +217,7 @@ static void print_maddr(FILE *fp, struct ma_info *list)
 		}
 		fprintf(fp, "%s",
 			format_host(list->addr.family,
-				    -1,
-				    list->addr.data,
-				    abuf, sizeof(abuf)));
+				    -1, list->addr.data));
 	}
 	if (list->users != 1)
 		fprintf(fp, " users %d", list->users);
diff --git a/ip/ipneigh.c b/ip/ipneigh.c
index 472555d..b99a120 100644
--- a/ip/ipneigh.c
+++ b/ip/ipneigh.c
@@ -193,7 +193,6 @@ int print_neigh(const struct sockaddr_nl *who, struct nlmsghdr *n, void *arg)
 	struct ndmsg *r = NLMSG_DATA(n);
 	int len = n->nlmsg_len;
 	struct rtattr * tb[NDA_MAX+1];
-	char abuf[256];
 
 	if (n->nlmsg_type != RTM_NEWNEIGH && n->nlmsg_type != RTM_DELNEIGH &&
 	    n->nlmsg_type != RTM_GETNEIGH) {
@@ -264,8 +263,7 @@ int print_neigh(const struct sockaddr_nl *who, struct nlmsghdr *n, void *arg)
 		fprintf(fp, "%s ",
 			format_host(r->ndm_family,
 				    RTA_PAYLOAD(tb[NDA_DST]),
-				    RTA_DATA(tb[NDA_DST]),
-				    abuf, sizeof(abuf)));
+				    RTA_DATA(tb[NDA_DST])));
 	}
 	if (!filter.index && r->ndm_ifindex)
 		fprintf(fp, "dev %s ", ll_index_to_name(r->ndm_ifindex));
diff --git a/ip/iproute.c b/ip/iproute.c
index eb5d145..2bc2041 100644
--- a/ip/iproute.c
+++ b/ip/iproute.c
@@ -366,8 +366,7 @@ int print_route(const struct sockaddr_nl *who, struct nlmsghdr *n, void *arg)
 		} else {
 			fprintf(fp, "%s ", format_host(r->rtm_family,
 						       RTA_PAYLOAD(tb[RTA_DST]),
-						       RTA_DATA(tb[RTA_DST]),
-						       abuf, sizeof(abuf))
+						       RTA_DATA(tb[RTA_DST]))
 				);
 		}
 	} else if (r->rtm_dst_len) {
@@ -386,8 +385,7 @@ int print_route(const struct sockaddr_nl *who, struct nlmsghdr *n, void *arg)
 		} else {
 			fprintf(fp, "from %s ", format_host(r->rtm_family,
 						       RTA_PAYLOAD(tb[RTA_SRC]),
-						       RTA_DATA(tb[RTA_SRC]),
-						       abuf, sizeof(abuf))
+						       RTA_DATA(tb[RTA_SRC]))
 				);
 		}
 	} else if (r->rtm_src_len) {
@@ -406,8 +404,7 @@ int print_route(const struct sockaddr_nl *who, struct nlmsghdr *n, void *arg)
 		fprintf(fp, "via %s ",
 			format_host(r->rtm_family,
 				    RTA_PAYLOAD(tb[RTA_GATEWAY]),
-				    RTA_DATA(tb[RTA_GATEWAY]),
-				    abuf, sizeof(abuf)));
+				    RTA_DATA(tb[RTA_GATEWAY])));
 	}
 	if (tb[RTA_OIF] && filter.oifmask != -1)
 		fprintf(fp, "dev %s ", ll_index_to_name(*(int*)RTA_DATA(tb[RTA_OIF])));
@@ -629,8 +626,7 @@ int print_route(const struct sockaddr_nl *who, struct nlmsghdr *n, void *arg)
 					fprintf(fp, " via %s ",
 						format_host(r->rtm_family,
 							    RTA_PAYLOAD(tb[RTA_GATEWAY]),
-							    RTA_DATA(tb[RTA_GATEWAY]),
-							    abuf, sizeof(abuf)));
+							    RTA_DATA(tb[RTA_GATEWAY])));
 				}
 				if (tb[RTA_FLOW]) {
 					__u32 to = rta_getattr_u32(tb[RTA_FLOW]);
diff --git a/ip/iprule.c b/ip/iprule.c
index 63d7fcc..14eb852 100644
--- a/ip/iprule.c
+++ b/ip/iprule.c
@@ -96,8 +96,7 @@ int print_rule(const struct sockaddr_nl *who, struct nlmsghdr *n, void *arg)
 		} else {
 			fprintf(fp, "from %s ", format_host(r->rtm_family,
 						       RTA_PAYLOAD(tb[FRA_SRC]),
-						       RTA_DATA(tb[FRA_SRC]),
-						       abuf, sizeof(abuf))
+						       RTA_DATA(tb[FRA_SRC]))
 				);
 		}
 	} else if (r->rtm_src_len) {
@@ -117,8 +116,7 @@ int print_rule(const struct sockaddr_nl *who, struct nlmsghdr *n, void *arg)
 		} else {
 			fprintf(fp, "to %s ", format_host(r->rtm_family,
 						       RTA_PAYLOAD(tb[FRA_DST]),
-						       RTA_DATA(tb[FRA_DST]),
-						       abuf, sizeof(abuf)));
+						       RTA_DATA(tb[FRA_DST])));
 		}
 	} else if (r->rtm_dst_len) {
 		fprintf(fp, "to 0/%d ", r->rtm_dst_len);
@@ -175,8 +173,7 @@ int print_rule(const struct sockaddr_nl *who, struct nlmsghdr *n, void *arg)
 			fprintf(fp, "map-to %s ",
 				format_host(r->rtm_family,
 					    RTA_PAYLOAD(tb[RTA_GATEWAY]),
-					    RTA_DATA(tb[RTA_GATEWAY]),
-					    abuf, sizeof(abuf)));
+					    RTA_DATA(tb[RTA_GATEWAY])));
 		} else
 			fprintf(fp, "masquerade");
 	} else if (r->rtm_type == FR_ACT_GOTO) {
diff --git a/ip/iptoken.c b/ip/iptoken.c
index 0d265e6..b8b0df0 100644
--- a/ip/iptoken.c
+++ b/ip/iptoken.c
@@ -51,7 +51,6 @@ static int print_token(const struct sockaddr_nl *who, struct nlmsghdr *n, void *
 	int len = n->nlmsg_len;
 	struct rtattr *tb[IFLA_MAX + 1];
 	struct rtattr *ltb[IFLA_INET6_MAX + 1];
-	char abuf[256];
 
 	if (n->nlmsg_type != RTM_NEWLINK)
 		return -1;
@@ -82,8 +81,7 @@ static int print_token(const struct sockaddr_nl *who, struct nlmsghdr *n, void *
 	fprintf(fp, "token %s ",
 		format_host(ifi->ifi_family,
 			    RTA_PAYLOAD(ltb[IFLA_INET6_TOKEN]),
-			    RTA_DATA(ltb[IFLA_INET6_TOKEN]),
-			    abuf, sizeof(abuf)));
+			    RTA_DATA(ltb[IFLA_INET6_TOKEN])));
 	fprintf(fp, "dev %s ", ll_index_to_name(ifi->ifi_index));
 	fprintf(fp, "\n");
 	fflush(fp);
diff --git a/ip/iptunnel.c b/ip/iptunnel.c
index b9b24e8..17b377c 100644
--- a/ip/iptunnel.c
+++ b/ip/iptunnel.c
@@ -346,7 +346,7 @@ static void print_tunnel(struct ip_tunnel_parm *p)
 	printf("%s: %s/ip  remote %s  local %s ",
 	       p->name,
 	       tnl_strproto(p->iph.protocol),
-	       p->iph.daddr ? format_host(AF_INET, 4, &p->iph.daddr, s1, sizeof(s1))  : "any",
+	       p->iph.daddr ? format_host_r(AF_INET, 4, &p->iph.daddr, s1, sizeof(s1))  : "any",
 	       p->iph.saddr ? rt_addr_n2a(AF_INET, 4, &p->iph.saddr, s2, sizeof(s2)) : "any");
 
 	if (p->iph.protocol == IPPROTO_IPV6 && (p->i_flags & SIT_ISATAP)) {
@@ -363,7 +363,7 @@ static void print_tunnel(struct ip_tunnel_parm *p)
 			if (prl[i].addr != htonl(INADDR_ANY)) {
 				printf(" %s %s ",
 					(prl[i].flags & PRL_DEFAULT) ? "pdr" : "pr",
-					format_host(AF_INET, 4, &prl[i].addr, s1, sizeof(s1)));
+					format_host(AF_INET, 4, &prl[i].addr));
 			}
 		}
 	}
@@ -398,7 +398,7 @@ static void print_tunnel(struct ip_tunnel_parm *p)
 		       ip6rd.prefixlen);
 		if (ip6rd.relay_prefix) {
 			printf("6rd-relay_prefix %s/%u ",
-			       format_host(AF_INET, 4, &ip6rd.relay_prefix, s1, sizeof(s1)),
+			       format_host(AF_INET, 4, &ip6rd.relay_prefix),
 			       ip6rd.relay_prefixlen);
 		}
 	}
diff --git a/ip/link_gre.c b/ip/link_gre.c
index 62acf46..25a4047 100644
--- a/ip/link_gre.c
+++ b/ip/link_gre.c
@@ -276,7 +276,6 @@ get_failed:
 
 static void gre_print_opt(struct link_util *lu, FILE *f, struct rtattr *tb[])
 {
-	char s1[1024];
 	char s2[64];
 	const char *local = "any";
 	const char *remote = "any";
@@ -290,7 +289,7 @@ static void gre_print_opt(struct link_util *lu, FILE *f, struct rtattr *tb[])
 		unsigned addr = rta_getattr_u32(tb[IFLA_GRE_REMOTE]);
 
 		if (addr)
-			remote = format_host(AF_INET, 4, &addr, s1, sizeof(s1));
+			remote = format_host(AF_INET, 4, &addr);
 	}
 
 	fprintf(f, "remote %s ", remote);
@@ -299,7 +298,7 @@ static void gre_print_opt(struct link_util *lu, FILE *f, struct rtattr *tb[])
 		unsigned addr = rta_getattr_u32(tb[IFLA_GRE_LOCAL]);
 
 		if (addr)
-			local = format_host(AF_INET, 4, &addr, s1, sizeof(s1));
+			local = format_host(AF_INET, 4, &addr);
 	}
 
 	fprintf(f, "local %s ", local);
diff --git a/ip/link_gre6.c b/ip/link_gre6.c
index e00ea09..e07a0ad 100644
--- a/ip/link_gre6.c
+++ b/ip/link_gre6.c
@@ -297,7 +297,6 @@ get_failed:
 
 static void gre_print_opt(struct link_util *lu, FILE *f, struct rtattr *tb[])
 {
-	char s1[1024];
 	char s2[64];
 	const char *local = "any";
 	const char *remote = "any";
@@ -321,7 +320,7 @@ static void gre_print_opt(struct link_util *lu, FILE *f, struct rtattr *tb[])
 		memcpy(&addr, RTA_DATA(tb[IFLA_GRE_REMOTE]), sizeof(addr));
 
 		if (memcmp(&addr, &in6_addr_any, sizeof(addr)))
-			remote = format_host(AF_INET6, sizeof(addr), &addr, s1, sizeof(s1));
+			remote = format_host(AF_INET6, sizeof(addr), &addr);
 	}
 
 	fprintf(f, "remote %s ", remote);
@@ -331,7 +330,7 @@ static void gre_print_opt(struct link_util *lu, FILE *f, struct rtattr *tb[])
 		memcpy(&addr, RTA_DATA(tb[IFLA_GRE_LOCAL]), sizeof(addr));
 
 		if (memcmp(&addr, &in6_addr_any, sizeof(addr)))
-			local = format_host(AF_INET6, sizeof(addr), &addr, s1, sizeof(s1));
+			local = format_host(AF_INET6, sizeof(addr), &addr);
 	}
 
 	fprintf(f, "local %s ", local);
diff --git a/ip/link_iptnl.c b/ip/link_iptnl.c
index 4d5422b..0d83310 100644
--- a/ip/link_iptnl.c
+++ b/ip/link_iptnl.c
@@ -258,7 +258,7 @@ static void iptunnel_print_opt(struct link_util *lu, FILE *f, struct rtattr *tb[
 		unsigned addr = rta_getattr_u32(tb[IFLA_IPTUN_REMOTE]);
 
 		if (addr)
-			remote = format_host(AF_INET, 4, &addr, s1, sizeof(s1));
+			remote = format_host(AF_INET, 4, &addr);
 	}
 
 	fprintf(f, "remote %s ", remote);
@@ -267,7 +267,7 @@ static void iptunnel_print_opt(struct link_util *lu, FILE *f, struct rtattr *tb[
 		unsigned addr = rta_getattr_u32(tb[IFLA_IPTUN_LOCAL]);
 
 		if (addr)
-			local = format_host(AF_INET, 4, &addr, s1, sizeof(s1));
+			local = format_host(AF_INET, 4, &addr);
 	}
 
 	fprintf(f, "local %s ", local);
@@ -323,8 +323,7 @@ static void iptunnel_print_opt(struct link_util *lu, FILE *f, struct rtattr *tb[
 		       prefixlen);
 		if (relayprefix) {
 			printf("6rd-relay_prefix %s/%u ",
-			       format_host(AF_INET, 4, &relayprefix, s1,
-					   sizeof(s1)),
+			       format_host(AF_INET, 4, &relayprefix),
 			       relayprefixlen);
 		}
 	}
diff --git a/ip/link_vti.c b/ip/link_vti.c
index f3fea33..83d6187 100644
--- a/ip/link_vti.c
+++ b/ip/link_vti.c
@@ -198,7 +198,6 @@ get_failed:
 
 static void vti_print_opt(struct link_util *lu, FILE *f, struct rtattr *tb[])
 {
-	char s1[1024];
 	char s2[64];
 	const char *local = "any";
 	const char *remote = "any";
@@ -210,7 +209,7 @@ static void vti_print_opt(struct link_util *lu, FILE *f, struct rtattr *tb[])
 		unsigned addr = *(__u32 *)RTA_DATA(tb[IFLA_VTI_REMOTE]);
 
 		if (addr)
-			remote = format_host(AF_INET, 4, &addr, s1, sizeof(s1));
+			remote = format_host(AF_INET, 4, &addr);
 	}
 
 	fprintf(f, "remote %s ", remote);
@@ -219,7 +218,7 @@ static void vti_print_opt(struct link_util *lu, FILE *f, struct rtattr *tb[])
 		unsigned addr = *(__u32 *)RTA_DATA(tb[IFLA_VTI_LOCAL]);
 
 		if (addr)
-			local = format_host(AF_INET, 4, &addr, s1, sizeof(s1));
+			local = format_host(AF_INET, 4, &addr);
 	}
 
 	fprintf(f, "local %s ", local);
diff --git a/ip/link_vti6.c b/ip/link_vti6.c
index c146f79..699a6ab 100644
--- a/ip/link_vti6.c
+++ b/ip/link_vti6.c
@@ -195,7 +195,6 @@ get_failed:
 
 static void vti6_print_opt(struct link_util *lu, FILE *f, struct rtattr *tb[])
 {
-	char s1[1024];
 	char s2[64];
 	const char *local = "any";
 	const char *remote = "any";
@@ -208,7 +207,7 @@ static void vti6_print_opt(struct link_util *lu, FILE *f, struct rtattr *tb[])
 	if (tb[IFLA_VTI_REMOTE]) {
 		memcpy(&daddr, RTA_DATA(tb[IFLA_VTI_REMOTE]), sizeof(daddr));
 
-		remote = format_host(AF_INET6, 16, &daddr, s1, sizeof(s1));
+		remote = format_host(AF_INET6, 16, &daddr);
 	}
 
 	fprintf(f, "remote %s ", remote);
@@ -216,7 +215,7 @@ static void vti6_print_opt(struct link_util *lu, FILE *f, struct rtattr *tb[])
 	if (tb[IFLA_VTI_LOCAL]) {
 		memcpy(&saddr, RTA_DATA(tb[IFLA_VTI_LOCAL]), sizeof(saddr));
 
-		local = format_host(AF_INET6, 16, &saddr, s1, sizeof(s1));
+		local = format_host(AF_INET6, 16, &saddr);
 	}
 
 	fprintf(f, "local %s ", local);
diff --git a/ip/tcp_metrics.c b/ip/tcp_metrics.c
index 7e7cf27..c55d9ad 100644
--- a/ip/tcp_metrics.c
+++ b/ip/tcp_metrics.c
@@ -94,7 +94,6 @@ static int process_msg(const struct sockaddr_nl *who, struct nlmsghdr *n,
 	struct genlmsghdr *ghdr;
 	struct rtattr *attrs[TCP_METRICS_ATTR_MAX + 1], *a;
 	int len = n->nlmsg_len;
-	char abuf[256];
 	inet_prefix addr;
 	int family, i, atype;
 
@@ -161,8 +160,7 @@ static int process_msg(const struct sockaddr_nl *who, struct nlmsghdr *n,
 		fprintf(fp, "Deleted ");
 
 	fprintf(fp, "%s",
-		format_host(family, RTA_PAYLOAD(a), &addr.data,
-			    abuf, sizeof(abuf)));
+		format_host(family, RTA_PAYLOAD(a), &addr.data));
 
 	a = attrs[TCP_METRICS_ATTR_AGE];
 	if (a) {
diff --git a/lib/utils.c b/lib/utils.c
index d3ed875..9764d75 100644
--- a/lib/utils.c
+++ b/lib/utils.c
@@ -780,7 +780,7 @@ static const char *resolve_address(const void *addr, int len, int af)
 #endif
 
 
-const char *format_host(int af, int len, const void *addr,
+const char *format_host_r(int af, int len, const void *addr,
 			char *buf, int buflen)
 {
 #ifdef RESOLVE_HOSTNAMES
@@ -816,6 +816,13 @@ const char *format_host(int af, int len, const void *addr,
 	return rt_addr_n2a(af, len, addr, buf, buflen);
 }
 
+const char *format_host(int af, int len, const void *addr)
+{
+	static char buf[256];
+
+	return format_host_r(af, len, addr, buf, 256);
+}
+
 
 char *hexstring_n2a(const __u8 *str, int len, char *buf, int blen)
 {
diff --git a/misc/ss.c b/misc/ss.c
index d438428..46b0925 100644
--- a/misc/ss.c
+++ b/misc/ss.c
@@ -1074,10 +1074,10 @@ static void inet_addr_print(const inet_prefix *a, int port, unsigned int ifindex
 			buf[0] = '*';
 			buf[1] = 0;
 		} else {
-			ap = format_host(AF_INET, 4, a->data, buf, sizeof(buf));
+			ap = format_host(AF_INET, 4, a->data);
 		}
 	} else {
-		ap = format_host(a->family, 16, a->data, buf, sizeof(buf));
+		ap = format_host(a->family, 16, a->data);
 		est_len = strlen(ap);
 		if (est_len <= addr_width)
 			est_len = addr_width;
@@ -2119,7 +2119,6 @@ static void tcp_show_info(const struct nlmsghdr *nlh, struct inet_diag_msg *r,
 
 static const char *format_host_sa(struct sockaddr_storage *sa)
 {
-	char buf[1024];
 	union {
 		struct sockaddr_in sin;
 		struct sockaddr_in6 sin6;
@@ -2127,11 +2126,9 @@ static const char *format_host_sa(struct sockaddr_storage *sa)
 
 	switch (sa->ss_family) {
 	case AF_INET:
-		return format_host(AF_INET, 4, &saddr->sin.sin_addr,
-				   buf, sizeof(buf));
+		return format_host(AF_INET, 4, &saddr->sin.sin_addr);
 	case AF_INET6:
-		return format_host(AF_INET6, 16, &saddr->sin6.sin6_addr,
-				   buf, sizeof(buf));
+		return format_host(AF_INET6, 16, &saddr->sin6.sin6_addr);
 	default:
 		return "";
 	}
diff --git a/tc/m_nat.c b/tc/m_nat.c
index 01ec032..df5c911 100644
--- a/tc/m_nat.c
+++ b/tc/m_nat.c
@@ -190,9 +190,9 @@ print_nat(struct action_util *au,FILE * f, struct rtattr *arg)
 
 	fprintf(f, " nat %s %s/%d %s %s", sel->flags & TCA_NAT_FLAG_EGRESS ?
 					  "egress" : "ingress",
-		format_host(AF_INET, 4, &sel->old_addr, buf1, sizeof(buf1)),
+		format_host_r(AF_INET, 4, &sel->old_addr, buf1, sizeof(buf1)),
 		len,
-		format_host(AF_INET, 4, &sel->new_addr, buf2, sizeof(buf2)),
+		format_host_r(AF_INET, 4, &sel->new_addr, buf2, sizeof(buf2)),
 		action_n2a(sel->action, buf3, sizeof (buf3)));
 
 	if (show_stats) {
-- 
1.8.3.1