[PATCH v3 iproute2 5/6] ip vrf: Add ipvrf_get_table

[David Ahern]

Add ipvrf_get_table to lookup table id for device name. Returns 0
on any error or if name is not a VRF device.

Signed-off-by: David Ahern <d...@cumulusnetworks.com>
---
 ip/ip_common.h  |  1 +
 ip/iplink_vrf.c | 66 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 67 insertions(+)

diff --git a/ip/ip_common.h b/ip/ip_common.h
index b747ea47122d..8faed6174f06 100644
--- a/ip/ip_common.h
+++ b/ip/ip_common.h
@@ -90,6 +90,7 @@ 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);
 
+__u32 ipvrf_get_table(char *name);
 bool name_is_vrf(const char *name);
 
 #ifndef        INFINITY_LIFE_TIME
diff --git a/ip/iplink_vrf.c b/ip/iplink_vrf.c
index 166f566e6d77..b4013773537f 100644
--- a/ip/iplink_vrf.c
+++ b/ip/iplink_vrf.c
@@ -97,6 +97,72 @@ struct link_util vrf_slave_link_util = {
        .slave          = true,
 };
 
+/* returns table id if name is a VRF device */
+__u32 ipvrf_get_table(char *name)
+{
+       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 rtattr *vrf_attr[IFLA_VRF_MAX + 1];
+       struct ifinfomsg *ifi;
+       __u32 tb_id = 0;
+       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;
+
+       ifi = NLMSG_DATA(&answer.n);
+       len = answer.n.nlmsg_len - NLMSG_LENGTH(sizeof(*ifi));
+       if (len < 0) {
+               fprintf(stderr, "BUG: Invalid response to link query.\n");
+               goto err;
+       }
+
+       parse_rtattr(tb, IFLA_MAX, IFLA_RTA(ifi), len);
+
+       if (!tb[IFLA_LINKINFO])
+               goto err;
+
+       parse_rtattr_nested(li, IFLA_INFO_MAX, tb[IFLA_LINKINFO]);
+
+       if (!li[IFLA_INFO_KIND] || !li[IFLA_INFO_DATA])
+               goto err;
+
+       if (strcmp(RTA_DATA(li[IFLA_INFO_KIND]), "vrf"))
+               goto err;
+
+       parse_rtattr_nested(vrf_attr, IFLA_VRF_MAX, li[IFLA_INFO_DATA]);
+       if (vrf_attr[IFLA_VRF_TABLE])
+               tb_id = rta_getattr_u32(vrf_attr[IFLA_VRF_TABLE]);
+
+       if (!tb_id)
+               fprintf(stderr, "BUG: VRF %s is missing table id\n", name);
+
+       return tb_id;
+
+err:
+       return 0;
+}
+
 bool name_is_vrf(const char *name)
 {
        struct {
-- 
2.1.4