From 3d76c7eea3caaddcc0608ad35a9e6fab3df11f8e Mon Sep 17 00:00:00 2001

From: Hangbin Liu <haliu@redhat.com>

Date: Wed, 8 Nov 2017 14:39:13 +0800

Subject: [PATCH] lib/libnetlink: update rtnl_talk to support malloc buff at

 run time

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1380803

Upstream Status: iproute2.git net-next commit 86bf43c7c2fd

Conflicts:

- iplink_get@ip/iplink.c: no function open_json_object() due to missing

  e4a1216aeb2a ("ip: iplink.c: open/close json obj for ip -brief -json link

  show dev DEV"). Lack of last parameter for print_linkinfo_brief() due to

  missing 63891c70137f ("ip address: Change print_linkinfo_brief to take

  filter as an input")

- gre_parse_opt@ip/link_gre.c: context conflicts due to missing new

  flag IFLA_GRE_ERSPAN_INDEX.

- gre_parse_opt@ip/link_gre6.c: context conflicts due to missing new

  flag IFLA_GRE_FWMARK.

- ip6tunnel_parse_opt@ip/link_ip6tnl.c: context conflicts due to missing new

  flag IFLA_IPTUN_FWMARK.

- iptunnel_parse_opt@ip/link_iptnl.c: context conflicts due to missing new

  flag IFLA_IPTUN_FWMARK.

- vti_parse_opt@ip/link_vti.c: context conflicts due to missing new flag

  IFLA_VTI_FWMARK

- vti6_parse_opt@ip/link_vti6.c: context conflicts due to missing new flag

  IFLA_VTI_FWMARK

commit 86bf43c7c2fdc33d7c021b4a1add1c8facbca51c

Author: Hangbin Liu <liuhangbin@gmail.com>

Date:   Thu Oct 26 09:41:47 2017 +0800

    lib/libnetlink: update rtnl_talk to support malloc buff at run time

    This is an update for 460c03f3f3cc ("iplink: double the buffer size also in

    iplink_get()"). After update, we will not need to double the buffer size

    every time when VFs number increased.

    With call like rtnl_talk(&rth, &req.n, NULL, 0), we can simply remove the

    length parameter.

    With call like rtnl_talk(&rth, nlh, nlh, sizeof(req), I add a new variable

    answer to avoid overwrite data in nlh, because it may has more info after

    nlh. also this will avoid nlh buffer not enough issue.

    We need to free answer after using.

    Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>

    Signed-off-by: Phil Sutter <phil@nwl.cc>

Signed-off-by: Hangbin Liu <haliu@redhat.com>

---

 bridge/fdb.c         |  2 +-

 bridge/link.c        |  2 +-

 bridge/mdb.c         |  2 +-

 bridge/vlan.c        |  2 +-

 genl/ctrl.c          | 19 ++++++++++++-------

 include/libnetlink.h |  6 +++---

 ip/ipaddress.c       |  4 ++--

 ip/ipaddrlabel.c     |  4 ++--

 ip/ipfou.c           |  4 ++--

 ip/ipila.c           |  4 ++--

 ip/ipl2tp.c          |  8 ++++----

 ip/iplink.c          | 38 +++++++++++++++++++-------------------

 ip/iplink_vrf.c      | 44 ++++++++++++++++++++------------------------

 ip/ipmacsec.c        |  2 +-

 ip/ipneigh.c         |  2 +-

 ip/ipnetns.c         | 23 ++++++++++++++---------

 ip/ipntable.c        |  2 +-

 ip/iproute.c         | 26 +++++++++++++++++---------

 ip/iprule.c          |  6 +++---

 ip/iptoken.c         |  2 +-

 ip/link_gre.c        | 11 +++++++----

 ip/link_gre6.c       | 11 +++++++----

 ip/link_ip6tnl.c     | 11 +++++++----

 ip/link_iptnl.c      | 11 +++++++----

 ip/link_vti.c        | 11 +++++++----

 ip/link_vti6.c       | 11 +++++++----

 ip/tcp_metrics.c     |  8 +++++---

 ip/xfrm_policy.c     | 25 +++++++++++++------------

 ip/xfrm_state.c      | 30 ++++++++++++++++--------------

 lib/libgenl.c        |  9 +++++++--

 lib/libnetlink.c     | 24 +++++++++++-------------

 misc/ss.c            |  2 +-

 tc/m_action.c        | 12 ++++++------

 tc/tc_class.c        |  2 +-

 tc/tc_filter.c       |  8 +++++---

 tc/tc_qdisc.c        |  2 +-

 36 files changed, 216 insertions(+), 174 deletions(-)

diff --git a/bridge/fdb.c b/bridge/fdb.c

index a71a78f23b202..4859edb2473b7 100644

--- a/bridge/fdb.c

+++ b/bridge/fdb.c

@@ -529,7 +529,7 @@ static int fdb_modify(int cmd, int flags, int argc, char **argv)

 		return -1;

 	}

-	if (rtnl_talk(&rth, &req.n, NULL, 0) < 0)

+	if (rtnl_talk(&rth, &req.n, NULL) < 0)

 		return -1;

 	return 0;

diff --git a/bridge/link.c b/bridge/link.c

index 93472ad3699e3..cc29a2adb2e01 100644

--- a/bridge/link.c

+++ b/bridge/link.c

@@ -426,7 +426,7 @@ static int brlink_modify(int argc, char **argv)

 		addattr_nest_end(&req.n, nest);

 	}

-	if (rtnl_talk(&rth, &req.n, NULL, 0) < 0)

+	if (rtnl_talk(&rth, &req.n, NULL) < 0)

 		return -1;

 	return 0;

diff --git a/bridge/mdb.c b/bridge/mdb.c

index e60ff3ef3f485..fbd8184dacf85 100644

--- a/bridge/mdb.c

+++ b/bridge/mdb.c

@@ -298,7 +298,7 @@ static int mdb_modify(int cmd, int flags, int argc, char **argv)

 	entry.vid = vid;

 	addattr_l(&req.n, sizeof(req), MDBA_SET_ENTRY, &entry, sizeof(entry));

-	if (rtnl_talk(&rth, &req.n, NULL, 0) < 0)

+	if (rtnl_talk(&rth, &req.n, NULL) < 0)

 		return -1;

 	return 0;

diff --git a/bridge/vlan.c b/bridge/vlan.c

index ebcdacee309bc..5d683595e0e32 100644

--- a/bridge/vlan.c

+++ b/bridge/vlan.c

@@ -133,7 +133,7 @@ static int vlan_modify(int cmd, int argc, char **argv)

 	addattr_nest_end(&req.n, afspec);

-	if (rtnl_talk(&rth, &req.n, NULL, 0) < 0)

+	if (rtnl_talk(&rth, &req.n, NULL) < 0)

 		return -1;

 	return 0;

diff --git a/genl/ctrl.c b/genl/ctrl.c

index 6abd52582d0d3..21e857cfcfc25 100644

--- a/genl/ctrl.c

+++ b/genl/ctrl.c

@@ -55,6 +55,7 @@ int genl_ctrl_resolve_family(const char *family)

 	};

 	struct nlmsghdr *nlh = &req.n;

 	struct genlmsghdr *ghdr = &req.g;

+	struct nlmsghdr *answer = NULL;

 	if (rtnl_open_byproto(&rth, 0, NETLINK_GENERIC) < 0) {

 		fprintf(stderr, "Cannot open generic netlink socket\n");

@@ -63,19 +64,19 @@ int genl_ctrl_resolve_family(const char *family)

 	addattr_l(nlh, 128, CTRL_ATTR_FAMILY_NAME, family, strlen(family) + 1);

-	if (rtnl_talk(&rth, nlh, nlh, sizeof(req)) < 0) {

+	if (rtnl_talk(&rth, nlh, &answer) < 0) {

 		fprintf(stderr, "Error talking to the kernel\n");

 		goto errout;

 	}

 	{

 		struct rtattr *tb[CTRL_ATTR_MAX + 1];

-		int len = nlh->nlmsg_len;

+		int len = answer->nlmsg_len;

 		struct rtattr *attrs;

-		if (nlh->nlmsg_type !=  GENL_ID_CTRL) {

+		if (answer->nlmsg_type !=  GENL_ID_CTRL) {

 			fprintf(stderr, "Not a controller message, nlmsg_len=%d "

-				"nlmsg_type=0x%x\n", nlh->nlmsg_len, nlh->nlmsg_type);

+				"nlmsg_type=0x%x\n", answer->nlmsg_len, answer->nlmsg_type);

 			goto errout;

 		}

@@ -88,10 +89,11 @@ int genl_ctrl_resolve_family(const char *family)

 		if (len < 0) {

 			fprintf(stderr, "wrong controller message len %d\n", len);

+			free(answer);

 			return -1;

 		}

-		attrs = (struct rtattr *) ((char *) ghdr + GENL_HDRLEN);

+		attrs = (struct rtattr *) ((char *) answer + NLMSG_LENGTH(GENL_HDRLEN));

 		parse_rtattr(tb, CTRL_ATTR_MAX, attrs, len);

 		if (tb[CTRL_ATTR_FAMILY_ID] == NULL) {

@@ -103,6 +105,7 @@ int genl_ctrl_resolve_family(const char *family)

 	}

 errout:

+	free(answer);

 	rtnl_close(&rth);

 	return ret;

 }

@@ -299,6 +302,7 @@ static int ctrl_list(int cmd, int argc, char **argv)

 		.g.cmd = CTRL_CMD_GETFAMILY,

 	};

 	struct nlmsghdr *nlh = &req.n;

+	struct nlmsghdr *answer = NULL;

 	if (rtnl_open_byproto(&rth, 0, NETLINK_GENERIC) < 0) {

 		fprintf(stderr, "Cannot open generic netlink socket\n");

@@ -331,12 +335,12 @@ static int ctrl_list(int cmd, int argc, char **argv)

 			goto ctrl_done;

 		}

-		if (rtnl_talk(&rth, nlh, nlh, sizeof(req)) < 0) {

+		if (rtnl_talk(&rth, nlh, &answer) < 0) {

 			fprintf(stderr, "Error talking to the kernel\n");

 			goto ctrl_done;

 		}

-		if (print_ctrl2(NULL, nlh, (void *) stdout) < 0) {

+		if (print_ctrl2(NULL, answer, (void *) stdout) < 0) {

 			fprintf(stderr, "Dump terminated\n");

 			goto ctrl_done;

 		}

@@ -358,6 +362,7 @@ static int ctrl_list(int cmd, int argc, char **argv)

 	ret = 0;

 ctrl_done:

+	free(answer);

 	rtnl_close(&rth);

 	return ret;

 }

diff --git a/include/libnetlink.h b/include/libnetlink.h

index 654aebc0f7632..2136d2bdd0379 100644

--- a/include/libnetlink.h

+++ b/include/libnetlink.h

@@ -82,13 +82,13 @@ int rtnl_dump_filter_nc(struct rtnl_handle *rth,

 #define rtnl_dump_filter(rth, filter, arg) \

 	rtnl_dump_filter_nc(rth, filter, arg, 0)

 int rtnl_talk(struct rtnl_handle *rtnl, struct nlmsghdr *n,

-	      struct nlmsghdr *answer, size_t len)

+	      struct nlmsghdr **answer)

 	__attribute__((warn_unused_result));

 int rtnl_talk_extack(struct rtnl_handle *rtnl, struct nlmsghdr *n,

-	      struct nlmsghdr *answer, size_t len, nl_ext_ack_fn_t errfn)

+	      struct nlmsghdr **answer, nl_ext_ack_fn_t errfn)

 	__attribute__((warn_unused_result));

 int rtnl_talk_suppress_rtnl_errmsg(struct rtnl_handle *rtnl, struct nlmsghdr *n,

-				   struct nlmsghdr *answer, size_t len)

+				   struct nlmsghdr **answer)

 	__attribute__((warn_unused_result));

 int rtnl_send(struct rtnl_handle *rth, const void *buf, int)

 	__attribute__((warn_unused_result));

diff --git a/ip/ipaddress.c b/ip/ipaddress.c

index b8d9c7d917fe8..7492075687a9e 100644

--- a/ip/ipaddress.c

+++ b/ip/ipaddress.c

@@ -1356,7 +1356,7 @@ static int restore_handler(const struct sockaddr_nl *nl,

 	ll_init_map(&rth);

-	ret = rtnl_talk(&rth, n, n, sizeof(*n));

+	ret = rtnl_talk(&rth, n, NULL);

 	if ((ret < 0) && (errno == EEXIST))

 		ret = 0;

@@ -2064,7 +2064,7 @@ static int ipaddr_modify(int cmd, int flags, int argc, char **argv)

 		return -1;

 	}

-	if (rtnl_talk(&rth, &req.n, NULL, 0) < 0)

+	if (rtnl_talk(&rth, &req.n, NULL) < 0)

 		return -2;

 	return 0;

diff --git a/ip/ipaddrlabel.c b/ip/ipaddrlabel.c

index 1d324dac02119..6ea9bfffdd0d1 100644

--- a/ip/ipaddrlabel.c

+++ b/ip/ipaddrlabel.c

@@ -176,7 +176,7 @@ static int ipaddrlabel_modify(int cmd, int argc, char **argv)

 	if (req.ifal.ifal_family == AF_UNSPEC)

 		req.ifal.ifal_family = AF_INET6;

-	if (rtnl_talk(&rth, &req.n, NULL, 0) < 0)

+	if (rtnl_talk(&rth, &req.n, NULL) < 0)

 		return -2;

 	return 0;

@@ -203,7 +203,7 @@ static int flush_addrlabel(const struct sockaddr_nl *who, struct nlmsghdr *n, vo

 		if (rtnl_open(&rth2, 0) < 0)

 			return -1;

-		if (rtnl_talk(&rth2, n, NULL, 0) < 0)

+		if (rtnl_talk(&rth2, n, NULL) < 0)

 			return -2;

 		rtnl_close(&rth2;;

diff --git a/ip/ipfou.c b/ip/ipfou.c

index 00dbe150710d2..23000dc696d6a 100644

--- a/ip/ipfou.c

+++ b/ip/ipfou.c

@@ -116,7 +116,7 @@ static int do_add(int argc, char **argv)

 	fou_parse_opt(argc, argv, &req.n, true);

-	if (rtnl_talk(&genl_rth, &req.n, NULL, 0) < 0)

+	if (rtnl_talk(&genl_rth, &req.n, NULL) < 0)

 		return -2;

 	return 0;

@@ -128,7 +128,7 @@ static int do_del(int argc, char **argv)

 	fou_parse_opt(argc, argv, &req.n, false);

-	if (rtnl_talk(&genl_rth, &req.n, NULL, 0) < 0)

+	if (rtnl_talk(&genl_rth, &req.n, NULL) < 0)

 		return -2;

 	return 0;

diff --git a/ip/ipila.c b/ip/ipila.c

index 843cc1652589f..0403fc4238b9d 100644

--- a/ip/ipila.c

+++ b/ip/ipila.c

@@ -220,7 +220,7 @@ static int do_add(int argc, char **argv)

 	ila_parse_opt(argc, argv, &req.n, true);

-	if (rtnl_talk(&genl_rth, &req.n, NULL, 0) < 0)

+	if (rtnl_talk(&genl_rth, &req.n, NULL) < 0)

 		return -2;

 	return 0;

@@ -232,7 +232,7 @@ static int do_del(int argc, char **argv)

 	ila_parse_opt(argc, argv, &req.n, false);

-	if (rtnl_talk(&genl_rth, &req.n, NULL, 0) < 0)

+	if (rtnl_talk(&genl_rth, &req.n, NULL) < 0)

 		return -2;

 	return 0;

diff --git a/ip/ipl2tp.c b/ip/ipl2tp.c

index 88664c909e11f..742adbe4f9c3a 100644

--- a/ip/ipl2tp.c

+++ b/ip/ipl2tp.c

@@ -129,7 +129,7 @@ static int create_tunnel(struct l2tp_parm *p)

 			addattr(&req.n, 1024, L2TP_ATTR_UDP_ZERO_CSUM6_RX);

 	}

-	if (rtnl_talk(&genl_rth, &req.n, NULL, 0) < 0)

+	if (rtnl_talk(&genl_rth, &req.n, NULL) < 0)

 		return -2;

 	return 0;

@@ -142,7 +142,7 @@ static int delete_tunnel(struct l2tp_parm *p)

 	addattr32(&req.n, 128, L2TP_ATTR_CONN_ID, p->tunnel_id);

-	if (rtnl_talk(&genl_rth, &req.n, NULL, 0) < 0)

+	if (rtnl_talk(&genl_rth, &req.n, NULL) < 0)

 		return -2;

 	return 0;

@@ -185,7 +185,7 @@ static int create_session(struct l2tp_parm *p)

 	if (p->ifname && p->ifname[0])

 		addattrstrz(&req.n, 1024, L2TP_ATTR_IFNAME, p->ifname);

-	if (rtnl_talk(&genl_rth, &req.n, NULL, 0) < 0)

+	if (rtnl_talk(&genl_rth, &req.n, NULL) < 0)

 		return -2;

 	return 0;

@@ -198,7 +198,7 @@ static int delete_session(struct l2tp_parm *p)

 	addattr32(&req.n, 1024, L2TP_ATTR_CONN_ID, p->tunnel_id);

 	addattr32(&req.n, 1024, L2TP_ATTR_SESSION_ID, p->session_id);

-	if (rtnl_talk(&genl_rth, &req.n, NULL, 0) < 0)

+	if (rtnl_talk(&genl_rth, &req.n, NULL) < 0)

 		return -2;

 	return 0;

diff --git a/ip/iplink.c b/ip/iplink.c

index 5afbadf0ce383..b08d227d44bee 100644

--- a/ip/iplink.c

+++ b/ip/iplink.c

@@ -247,19 +247,26 @@ static int nl_get_ll_addr_len(unsigned int dev_index)

 			.ifi_index = dev_index,

 		}

 	};

+	struct nlmsghdr *answer;

 	struct rtattr *tb[IFLA_MAX+1];

-	if (rtnl_talk(&rth, &req.n, &req.n, sizeof(req)) < 0)

+	if (rtnl_talk(&rth, &req.n, &answer) < 0)

 		return -1;

-	len = req.n.nlmsg_len - NLMSG_LENGTH(sizeof(req.i));

-	if (len < 0)

+	len = answer->nlmsg_len - NLMSG_LENGTH(sizeof(struct ifinfomsg));

+	if (len < 0) {

+		free(answer);

 		return -1;

+	}

-	parse_rtattr_flags(tb, IFLA_MAX, IFLA_RTA(&req.i), len, NLA_F_NESTED);

-	if (!tb[IFLA_ADDRESS])

+	parse_rtattr_flags(tb, IFLA_MAX, IFLA_RTA(NLMSG_DATA(answer)),

+			   len, NLA_F_NESTED);

+	if (!tb[IFLA_ADDRESS]) {

+		free(answer);

 		return -1;

+	}

+	free(answer);

 	return RTA_PAYLOAD(tb[IFLA_ADDRESS]);

 }

@@ -903,7 +910,7 @@ static int iplink_modify(int cmd, unsigned int flags, int argc, char **argv)

 			req.i.ifi_index = 0;

 			addattr32(&req.n, sizeof(req), IFLA_GROUP, group);

-			if (rtnl_talk(&rth, &req.n, NULL, 0) < 0)

+			if (rtnl_talk(&rth, &req.n, NULL) < 0)

 				return -2;

 			return 0;

 		}

@@ -998,7 +1005,7 @@ static int iplink_modify(int cmd, unsigned int flags, int argc, char **argv)

 		return -1;

 	}

-	if (rtnl_talk(&rth, &req.n, NULL, 0) < 0)

+	if (rtnl_talk(&rth, &req.n, NULL) < 0)

 		return -2;

 	return 0;

@@ -1013,10 +1020,7 @@ int iplink_get(unsigned int flags, char *name, __u32 filt_mask)

 		.n.nlmsg_type = RTM_GETLINK,

 		.i.ifi_family = preferred_family,

 	};

-	struct {

-		struct nlmsghdr n;

-		char buf[32768];

-	} answer;

+	struct nlmsghdr *answer;

 	if (name) {

 		len = strlen(name) + 1;

@@ -1029,19 +1033,15 @@ int iplink_get(unsigned int flags, char *name, __u32 filt_mask)

 	}

 	addattr32(&req.n, sizeof(req), IFLA_EXT_MASK, filt_mask);

-	if (rtnl_talk(&rth, &req.n, &answer.n, sizeof(answer)) < 0)

-		return -2;

-	if (answer.n.nlmsg_len > sizeof(answer.buf)) {

-		fprintf(stderr, "Message truncated from %u to %lu\n",

-			answer.n.nlmsg_len, sizeof(answer.buf));

+	if (rtnl_talk(&rth, &req.n, &answer) < 0)

 		return -2;

-	}

 	if (brief)

-		print_linkinfo_brief(NULL, &answer.n, stdout);

+		print_linkinfo_brief(NULL, answer, stdout);

 	else

-		print_linkinfo(NULL, &answer.n, stdout);

+		print_linkinfo(NULL, answer, stdout);

+	free(answer);

 	return 0;

 }

diff --git a/ip/iplink_vrf.c b/ip/iplink_vrf.c

index 917630e853375..370bb86815a80 100644

--- a/ip/iplink_vrf.c

+++ b/ip/iplink_vrf.c

@@ -114,10 +114,7 @@ __u32 ipvrf_get_table(const char *name)

 			.ifi_family  = preferred_family,

 		},

 	};

-	struct {

-		struct nlmsghdr n;

-		char buf[8192];

-	} answer;

+	struct nlmsghdr *answer;

 	struct rtattr *tb[IFLA_MAX+1];

 	struct rtattr *li[IFLA_INFO_MAX+1];

 	struct rtattr *vrf_attr[IFLA_VRF_MAX + 1];

@@ -127,8 +124,7 @@ __u32 ipvrf_get_table(const char *name)

 	addattr_l(&req.n, sizeof(req), IFLA_IFNAME, name, strlen(name) + 1);

-	if (rtnl_talk_suppress_rtnl_errmsg(&rth, &req.n,

-					   &answer.n, sizeof(answer)) < 0) {

+	if (rtnl_talk_suppress_rtnl_errmsg(&rth, &req.n, &answer) < 0) {

 		/* special case "default" vrf to be the main table */

 		if (errno == ENODEV && !strcmp(name, "default"))

 			rtnl_rttable_a2n(&tb_id, "main");

@@ -136,25 +132,25 @@ __u32 ipvrf_get_table(const char *name)

 		return tb_id;

 	}

-	ifi = NLMSG_DATA(&answer.n);

-	len = answer.n.nlmsg_len - NLMSG_LENGTH(sizeof(*ifi));

+	ifi = NLMSG_DATA(answer);

+	len = answer->nlmsg_len - NLMSG_LENGTH(sizeof(*ifi));

 	if (len < 0) {

 		fprintf(stderr, "BUG: Invalid response to link query.\n");

-		return 0;

+		goto out;

 	}

 	parse_rtattr(tb, IFLA_MAX, IFLA_RTA(ifi), len);

 	if (!tb[IFLA_LINKINFO])

-		return 0;

+		goto out;

 	parse_rtattr_nested(li, IFLA_INFO_MAX, tb[IFLA_LINKINFO]);

 	if (!li[IFLA_INFO_KIND] || !li[IFLA_INFO_DATA])

-		return 0;

+		goto out;

 	if (strcmp(RTA_DATA(li[IFLA_INFO_KIND]), "vrf"))

-		return 0;

+		goto out;

 	parse_rtattr_nested(vrf_attr, IFLA_VRF_MAX, li[IFLA_INFO_DATA]);

 	if (vrf_attr[IFLA_VRF_TABLE])

@@ -163,6 +159,8 @@ __u32 ipvrf_get_table(const char *name)

 	if (!tb_id)

 		fprintf(stderr, "BUG: VRF %s is missing table id\n", name);

+out:

+	free(answer);

 	return tb_id;

 }

@@ -182,10 +180,7 @@ int name_is_vrf(const char *name)

 			.ifi_family  = preferred_family,

 		},

 	};

-	struct {

-		struct nlmsghdr n;

-		char buf[8192];

-	} answer;

+	struct nlmsghdr *answer;

 	struct rtattr *tb[IFLA_MAX+1];

 	struct rtattr *li[IFLA_INFO_MAX+1];

 	struct ifinfomsg *ifi;

@@ -193,29 +188,30 @@ int name_is_vrf(const char *name)

 	addattr_l(&req.n, sizeof(req), IFLA_IFNAME, name, strlen(name) + 1);

-	if (rtnl_talk_suppress_rtnl_errmsg(&rth, &req.n,

-					   &answer.n, sizeof(answer)) < 0)

+	if (rtnl_talk_suppress_rtnl_errmsg(&rth, &req.n, &answer) < 0)

 		return 0;

-	ifi = NLMSG_DATA(&answer.n);

-	len = answer.n.nlmsg_len - NLMSG_LENGTH(sizeof(*ifi));

+	ifi = NLMSG_DATA(answer);

+	len = answer->nlmsg_len - NLMSG_LENGTH(sizeof(*ifi));

 	if (len < 0) {

 		fprintf(stderr, "BUG: Invalid response to link query.\n");

-		return 0;

+		goto out;

 	}

 	parse_rtattr(tb, IFLA_MAX, IFLA_RTA(ifi), len);

 	if (!tb[IFLA_LINKINFO])

-		return 0;

+		goto out;

 	parse_rtattr_nested(li, IFLA_INFO_MAX, tb[IFLA_LINKINFO]);

 	if (!li[IFLA_INFO_KIND])

-		return 0;

+		goto out;

 	if (strcmp(RTA_DATA(li[IFLA_INFO_KIND]), "vrf"))

-		return 0;

+		goto out;

+out:

+	free(answer);

 	return ifi->ifi_index;

 }

diff --git a/ip/ipmacsec.c b/ip/ipmacsec.c

index aa89a00f5aad6..9a2d0ebf82091 100644

--- a/ip/ipmacsec.c

+++ b/ip/ipmacsec.c

@@ -421,7 +421,7 @@ static int do_modify_nl(enum cmd c, enum macsec_nl_commands cmd, int ifindex,

 	addattr_nest_end(&req.n, attr_sa);

 talk:

-	if (rtnl_talk(&genl_rth, &req.n, NULL, 0) < 0)

+	if (rtnl_talk(&genl_rth, &req.n, NULL) < 0)

 		return -2;

 	return 0;

diff --git a/ip/ipneigh.c b/ip/ipneigh.c

index 9c38a60ddf4fe..32f2d553c712f 100644

--- a/ip/ipneigh.c

+++ b/ip/ipneigh.c

@@ -184,7 +184,7 @@ static int ipneigh_modify(int cmd, int flags, int argc, char **argv)

 		return -1;

 	}

-	if (rtnl_talk(&rth, &req.n, NULL, 0) < 0)

+	if (rtnl_talk(&rth, &req.n, NULL) < 0)

 		exit(2);

 	return 0;

diff --git a/ip/ipnetns.c b/ip/ipnetns.c

index 4254994442ccd..1c0ade90dee5e 100644

--- a/ip/ipnetns.c

+++ b/ip/ipnetns.c

@@ -95,12 +95,13 @@ static int get_netnsid_from_name(const char *name)

 		struct nlmsghdr n;

 		struct rtgenmsg g;

 		char            buf[1024];

-	} answer, req = {

+	} req = {

 		.n.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtgenmsg)),

 		.n.nlmsg_flags = NLM_F_REQUEST,

 		.n.nlmsg_type = RTM_GETNSID,

 		.g.rtgen_family = AF_UNSPEC,

 	};

+	struct nlmsghdr *answer;

 	struct rtattr *tb[NETNSA_MAX + 1];

 	struct rtgenmsg *rthdr;

 	int len, fd;

@@ -110,26 +111,30 @@ static int get_netnsid_from_name(const char *name)

 		return fd;

 	addattr32(&req.n, 1024, NETNSA_FD, fd);

-	if (rtnl_talk(&rtnsh, &req.n, &answer.n, sizeof(answer)) < 0) {

+	if (rtnl_talk(&rtnsh, &req.n, &answer) < 0) {

 		close(fd);

 		return -2;

 	}

 	close(fd);

 	/* Validate message and parse attributes */

-	if (answer.n.nlmsg_type == NLMSG_ERROR)

-		return -1;

+	if (answer->nlmsg_type == NLMSG_ERROR)

+		goto err_out;

-	rthdr = NLMSG_DATA(&answer.n);

-	len = answer.n.nlmsg_len - NLMSG_SPACE(sizeof(*rthdr));

+	rthdr = NLMSG_DATA(answer);

+	len = answer->nlmsg_len - NLMSG_SPACE(sizeof(*rthdr));

 	if (len < 0)

-		return -1;

+		goto err_out;

 	parse_rtattr(tb, NETNSA_MAX, NETNS_RTA(rthdr), len);

-	if (tb[NETNSA_NSID])

+	if (tb[NETNSA_NSID]) {

+		free(answer);

 		return rta_getattr_u32(tb[NETNSA_NSID]);

+	}

+err_out:

+	free(answer);

 	return -1;

 }

@@ -690,7 +695,7 @@ static int set_netnsid_from_name(const char *name, int nsid)

 	addattr32(&req.n, 1024, NETNSA_FD, fd);

 	addattr32(&req.n, 1024, NETNSA_NSID, nsid);

-	if (rtnl_talk(&rth, &req.n, NULL, 0) < 0)

+	if (rtnl_talk(&rth, &req.n, NULL) < 0)

 		err = -2;

 	close(fd);

diff --git a/ip/ipntable.c b/ip/ipntable.c

index 879626ee4f491..65063321c85f8 100644

--- a/ip/ipntable.c

+++ b/ip/ipntable.c

@@ -306,7 +306,7 @@ static int ipntable_modify(int cmd, int flags, int argc, char **argv)

 			  RTA_PAYLOAD(parms_rta));

 	}

-	if (rtnl_talk(&rth, &req.n, NULL, 0) < 0)

+	if (rtnl_talk(&rth, &req.n, NULL) < 0)

 		exit(2);

 	return 0;

diff --git a/ip/iproute.c b/ip/iproute.c

index 5e23613dadbaf..35fdce8a64f35 100644

--- a/ip/iproute.c

+++ b/ip/iproute.c

@@ -1271,7 +1271,7 @@ static int iproute_modify(int cmd, unsigned int flags, int argc, char **argv)

 	if (!type_ok && req.r.rtm_family == AF_MPLS)

 		req.r.rtm_type = RTN_UNICAST;

-	if (rtnl_talk(&rth, &req.n, NULL, 0) < 0)

+	if (rtnl_talk(&rth, &req.n, NULL) < 0)

 		return -2;

 	return 0;

@@ -1649,6 +1649,7 @@ static int iproute_get(int argc, char **argv)

 	};

 	char  *idev = NULL;

 	char  *odev = NULL;

+	struct nlmsghdr *answer;

 	int connected = 0;

 	int from_ok = 0;

 	unsigned int mark = 0;

@@ -1753,26 +1754,29 @@ static int iproute_get(int argc, char **argv)

 	req.r.rtm_flags |= RTM_F_LOOKUP_TABLE;

-	if (rtnl_talk(&rth, &req.n, &req.n, sizeof(req)) < 0)

+	if (rtnl_talk(&rth, &req.n, &answer) < 0)