libnetlink: Add variant of rtnl_talk that does not display RTNETLINK answers error
iplink_vrf has 2 functions used to validate a user given device name is
a VRF device and to return the table id. If the user string is not a
device name ip commands with a vrf keyword show a confusing error
message: "RTNETLINK answers: No such device".
Add a variant of rtnl_talk that does not display the "RTNETLINK answers"
message and update iplink_vrf to use it.
Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
diff --git a/include/libnetlink.h b/include/libnetlink.h
index 751ebf1..bd0267d 100644
--- a/include/libnetlink.h
+++ b/include/libnetlink.h
@@ -81,6 +81,9 @@
int rtnl_talk(struct rtnl_handle *rtnl, struct nlmsghdr *n,
struct nlmsghdr *answer, size_t len)
__attribute__((warn_unused_result));
+int rtnl_talk_suppress_rtnl_errmsg(struct rtnl_handle *rtnl, struct nlmsghdr *n,
+ struct nlmsghdr *answer, size_t len)
+ __attribute__((warn_unused_result));
int rtnl_send(struct rtnl_handle *rth, const void *buf, int)
__attribute__((warn_unused_result));
int rtnl_send_check(struct rtnl_handle *rth, const void *buf, int)
diff --git a/ip/iplink_vrf.c b/ip/iplink_vrf.c
index c101ed7..917630e 100644
--- a/ip/iplink_vrf.c
+++ b/ip/iplink_vrf.c
@@ -13,6 +13,7 @@
#include <string.h>
#include <sys/socket.h>
#include <linux/if_link.h>
+#include <errno.h>
#include "rt_names.h"
#include "utils.h"
@@ -126,8 +127,14 @@
addattr_l(&req.n, sizeof(req), IFLA_IFNAME, name, strlen(name) + 1);
- if (rtnl_talk(&rth, &req.n, &answer.n, sizeof(answer)) < 0)
- return 0;
+ if (rtnl_talk_suppress_rtnl_errmsg(&rth, &req.n,
+ &answer.n, sizeof(answer)) < 0) {
+ /* special case "default" vrf to be the main table */
+ if (errno == ENODEV && !strcmp(name, "default"))
+ rtnl_rttable_a2n(&tb_id, "main");
+
+ return tb_id;
+ }
ifi = NLMSG_DATA(&answer.n);
len = answer.n.nlmsg_len - NLMSG_LENGTH(sizeof(*ifi));
@@ -186,7 +193,8 @@
addattr_l(&req.n, sizeof(req), IFLA_IFNAME, name, strlen(name) + 1);
- if (rtnl_talk(&rth, &req.n, &answer.n, sizeof(answer)) < 0)
+ if (rtnl_talk_suppress_rtnl_errmsg(&rth, &req.n,
+ &answer.n, sizeof(answer)) < 0)
return 0;
ifi = NLMSG_DATA(&answer.n);
diff --git a/lib/libnetlink.c b/lib/libnetlink.c
index a5db168..9d7e89a 100644
--- a/lib/libnetlink.c
+++ b/lib/libnetlink.c
@@ -12,6 +12,7 @@
#include <stdio.h>
#include <stdlib.h>
+#include <stdbool.h>
#include <unistd.h>
#include <syslog.h>
#include <fcntl.h>
@@ -397,8 +398,9 @@
return rtnl_dump_filter_l(rth, a);
}
-int rtnl_talk(struct rtnl_handle *rtnl, struct nlmsghdr *n,
- struct nlmsghdr *answer, size_t maxlen)
+static int __rtnl_talk(struct rtnl_handle *rtnl, struct nlmsghdr *n,
+ struct nlmsghdr *answer, size_t maxlen,
+ bool show_rtnl_err)
{
int status;
unsigned int seq;
@@ -485,7 +487,7 @@
return 0;
}
- if (rtnl->proto != NETLINK_SOCK_DIAG)
+ if (rtnl->proto != NETLINK_SOCK_DIAG && show_rtnl_err)
fprintf(stderr,
"RTNETLINK answers: %s\n",
strerror(-err->error));
@@ -517,6 +519,18 @@
}
}
+int rtnl_talk(struct rtnl_handle *rtnl, struct nlmsghdr *n,
+ struct nlmsghdr *answer, size_t maxlen)
+{
+ return __rtnl_talk(rtnl, n, answer, maxlen, true);
+}
+
+int rtnl_talk_suppress_rtnl_errmsg(struct rtnl_handle *rtnl, struct nlmsghdr *n,
+ struct nlmsghdr *answer, size_t maxlen)
+{
+ return __rtnl_talk(rtnl, n, answer, maxlen, false);
+}
+
int rtnl_listen_all_nsid(struct rtnl_handle *rth)
{
unsigned int on = 1;