NLM: Support IPv6 scope IDs in nlm_display_address()

Scope ID support is needed since the kernel's NSM implementation is
about to use these displayed addresses as a mon_name in some cases.

When nsm_use_hostnames is zero, without scope ID support NSM will fail
to handle peers that contact us via a link-local address.  Link-local
addresses do not work without an interface ID, which is stored in the
sockaddr's sin6_scope_id field.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

1 files changed, 9 insertions, 1 deletions

diff --git a/include/linux/lockd/lockd.h b/include/linux/lockd/lockd.h
index dae22cb4c38d..80a0a2cff2b8 100644
--- a/include/linux/lockd/lockd.h
+++ b/include/linux/lockd/lockd.h
@@ -68,6 +68,14 @@ struct nlm_host {
         char                    *h_addrbuf;     /* address eyecatcher */
 };
 
+/*
+ * The largest string sm_addrbuf should hold is a full-size IPv6 address
+ * (no "::" anywhere) with a scope ID.  The buffer size is computed to
+ * hold eight groups of colon-separated four-hex-digit numbers, a
+ * percent sign, a scope id (at most 32 bits, in decimal), and NUL.
+ */
+#define NSM_ADDRBUF             ((8 * 4 + 7) + (1 + 10) + 1)
+
 struct nsm_handle {
         struct list_head        sm_link;
         atomic_t                sm_count;
@@ -76,7 +84,7 @@ struct nsm_handle {
         size_t                  sm_addrlen;
         unsigned int            sm_monitored : 1,
                                 sm_sticky : 1;  /* don't unmonitor */
-        char                    sm_addrbuf[48]; /* address eyecatcher */
+        char                    sm_addrbuf[NSM_ADDRBUF];
 };
 
 /*