snmp: let handlers accept OID from a lesser prefix

Most table handlers do not expect to be given an OID whose prefix is
outside what they can handle. This is not a problem with the SMUX
implementation since it always correct the OID such that the prefix
matches. However, this is not the case for the AgentX
implementation. A new function, smux_header_table() is used to do this
normalization.

2 files changed, 22 insertions, 0 deletions

diff --git a/lib/smux.h b/lib/smux.h
index b29fdc72..72b4eaf0 100644
--- a/lib/smux.h
+++ b/lib/smux.h
@@ -75,6 +75,8 @@ extern void smux_register_mib(const char *, struct variable *,
                               size_t, int, oid [], size_t);
 extern int smux_header_generic (struct variable *, oid [], size_t *, 
                                 int, size_t *, WriteMethod **);
+extern int smux_header_table (struct variable *, oid *, size_t *, 
+			      int, size_t *, WriteMethod **);
 
 /* For traps, three OID are provided:
 
diff --git a/lib/snmp.c b/lib/snmp.c
index d7b1d953..79595a1e 100644
--- a/lib/snmp.c
+++ b/lib/snmp.c
@@ -110,4 +110,24 @@ smux_header_generic (struct variable *v, oid *name, size_t *length, int exact,
 
   return MATCH_SUCCEEDED;
 }
+
+int
+smux_header_table (struct variable *v, oid *name, size_t *length, int exact,
+		   size_t *var_len, WriteMethod **write_method)
+{
+  /* If the requested OID name is less than OID prefix we
+     handle, adjust it to our prefix. */
+  if ((oid_compare (name, *length, v->name, v->namelen)) < 0)
+    {
+      if (exact)
+	return MATCH_FAILED;
+      oid_copy(name, v->name, v->namelen);
+      *length = v->namelen;
+    }
+
+  *write_method = 0;
+  *var_len = sizeof(long);
+
+  return MATCH_SUCCEEDED;
+}
 #endif /* HAVE_SNMP */