Re: [PATCH iproute2 1/6] ip vrf: Add name_is_vrf

On 6/29/16 9:06 AM, Stephen Hemminger wrote:

On Mon, 27 Jun 2016 11:50:56 -0700
David Ahern [off-list ref] wrote:

quoted

diff --git a/ip/ip_common.h b/ip/ip_common.h
index e8da9e034b15..410eb135774a 100644
--- a/ip/ip_common.h
+++ b/ip/ip_common.h

@@ -90,6 +90,8 @@ struct link_util *get_link_slave_kind(const char *slave_kind);

 void br_dump_bridge_id(const struct ifla_bridge_id *id, char *buf, size_t len);

+bool name_is_vrf(char *name);
+
 #ifndef	INFINITY_LIFE_TIME
 #define     INFINITY_LIFE_TIME      0xFFFFFFFFU
 #endif

diff --git a/ip/iplink_vrf.c b/ip/iplink_vrf.c
index e3c7b4652da5..abd43c08423e 100644
--- a/ip/iplink_vrf.c
+++ b/ip/iplink_vrf.c

@@ -96,3 +96,56 @@ struct link_util vrf_slave_link_util = {
 	.print_opt	= vrf_slave_print_opt,
 	.slave          = true,
 };
+
+bool name_is_vrf(char *name)

Why not?
bool name_is_vrf(const char *name)

sure.

quoted

+{
+	struct {
+		struct nlmsghdr		n;
+		struct ifinfomsg	i;
+		char			buf[1024];
+	} req = {
+		.n = {
+			.nlmsg_len   = NLMSG_LENGTH(sizeof(struct ifinfomsg)),
+			.nlmsg_flags = NLM_F_REQUEST,
+			.nlmsg_type  = RTM_GETLINK,
+		},
+		.i = {
+			.ifi_family  = preferred_family,
+		},
+	};
+	struct {
+		struct nlmsghdr n;
+		char buf[8192];
+	} answer;
+	struct rtattr *tb[IFLA_MAX+1];
+	struct rtattr *li[IFLA_INFO_MAX+1];
+	struct ifinfomsg *ifi;
+	int len;
+
+	addattr_l(&req.n, sizeof(req), IFLA_IFNAME, name, strlen(name) + 1);
+
+	if (rtnl_talk(&rth, &req.n, &answer.n, sizeof(answer)) < 0)
+		goto err;

Just return false instead of all these goto's?
Also you might want to give some indication of error.

Any failure and the user gets the message "not a VRF". The reason can be the device is not a VRF or the device does not exist but that's the same thing in this case:

$ ./ip link show vrf foo
Error: argument "foo" is wrong: Not a valid VRF name

$ ./ip link show vrf eth1
Error: argument "eth1" is wrong: Not a valid VRF name