[PATCH iproute2-next v2 1/2] iplink: print warning for missing VF data

[Edwin Peer]

The kernel might truncate VF info in IFLA_VFINFO_LIST. Compare the
expected number of VFs in IFLA_NUM_VF to how many were found in the
list and warn accordingly.

Signed-off-by: Edwin Peer <edwin.p...@broadcom.com>
---
 ip/ipaddress.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/ip/ipaddress.c b/ip/ipaddress.c
index 571346b15cc3..0bbcee2b3bb2 100644
--- a/ip/ipaddress.c
+++ b/ip/ipaddress.c
@@ -922,6 +922,7 @@ int print_linkinfo(struct nlmsghdr *n, void *arg)
        const char *name;
        unsigned int m_flag = 0;
        SPRINT_BUF(b1);
+       bool truncated_vfs = false;
 
        if (n->nlmsg_type != RTM_NEWLINK && n->nlmsg_type != RTM_DELLINK)
                return 0;
@@ -1199,15 +1200,18 @@ int print_linkinfo(struct nlmsghdr *n, void *arg)
 
        if ((do_link || show_details) && tb[IFLA_VFINFO_LIST] && 
tb[IFLA_NUM_VF]) {
                struct rtattr *i, *vflist = tb[IFLA_VFINFO_LIST];
-               int rem = RTA_PAYLOAD(vflist);
+               int rem = RTA_PAYLOAD(vflist), count = 0;
 
                open_json_array(PRINT_JSON, "vfinfo_list");
                for (i = RTA_DATA(vflist); RTA_OK(i, rem); i = RTA_NEXT(i, 
rem)) {
                        open_json_object(NULL);
                        print_vfinfo(fp, ifi, i);
                        close_json_object();
+                       count++;
                }
                close_json_array(PRINT_JSON, NULL);
+               if (count != rta_getattr_u32(tb[IFLA_NUM_VF]))
+                       truncated_vfs = true;
        }
 
        if (tb[IFLA_PROP_LIST]) {
@@ -1228,6 +1232,9 @@ int print_linkinfo(struct nlmsghdr *n, void *arg)
 
        print_string(PRINT_FP, NULL, "%s", "\n");
        fflush(fp);
+       /* prettier here if stderr and stdout go to the same place */
+       if (truncated_vfs)
+               fprintf(stderr, "Truncated VF list: %s\n", name);
        return 1;
 }
 
-- 
2.30.0

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