smux: isolate SMUX implementation from SNMP implementation

lib/snmp.c gets OID related helper functions that can be used with
another SNMP interface. smux.h is cleaned of SMUX specific bits to
only expose functions that may be used by an alternative
implementation. We also do not redefine functions already present in
NetSNMP. Just use the appropriate headers.
diff --git a/lib/smux.c b/lib/smux.c
index 145ec90..a5d84a8 100644
--- a/lib/smux.c
+++ b/lib/smux.c
@@ -34,6 +34,45 @@
 #include "sockunion.h"
 #include "smux.h"
 
+#define SMUX_PORT_DEFAULT 199
+
+#define SMUXMAXPKTSIZE    1500
+#define SMUXMAXSTRLEN      256
+
+#define SMUX_OPEN       (ASN_APPLICATION | ASN_CONSTRUCTOR | 0)
+#define SMUX_CLOSE      (ASN_APPLICATION | ASN_PRIMITIVE | 1)
+#define SMUX_RREQ       (ASN_APPLICATION | ASN_CONSTRUCTOR | 2)
+#define SMUX_RRSP       (ASN_APPLICATION | ASN_PRIMITIVE | 3)
+#define SMUX_SOUT       (ASN_APPLICATION | ASN_PRIMITIVE | 4)
+
+#define SMUX_GET        (ASN_CONTEXT | ASN_CONSTRUCTOR | 0)
+#define SMUX_GETNEXT    (ASN_CONTEXT | ASN_CONSTRUCTOR | 1)
+#define SMUX_GETRSP     (ASN_CONTEXT | ASN_CONSTRUCTOR | 2)
+#define SMUX_SET	(ASN_CONTEXT | ASN_CONSTRUCTOR | 3)
+#define SMUX_TRAP	(ASN_CONTEXT | ASN_CONSTRUCTOR | 4)
+
+#define SMUX_MAX_FAILURE 3
+
+/* SNMP tree. */
+struct subtree
+{
+  /* Tree's oid. */
+  oid name[MAX_OID_LEN];
+  u_char name_len;
+
+  /* List of the variables. */
+  struct variable *variables;
+
+  /* Length of the variables list. */
+  int variables_num;
+
+  /* Width of the variables list. */
+  int variables_width;
+
+  /* Registered flag. */
+  int registered;
+};
+
 #define min(A,B) ((A) < (B) ? (A) : (B))
 
 enum smux_event {SMUX_SCHEDULE, SMUX_CONNECT, SMUX_READ};
@@ -76,62 +115,6 @@
 /* thread master */
 static struct thread_master *master;
 
-void *
-oid_copy (void *dest, const void *src, size_t size)
-{
-  return memcpy (dest, src, size * sizeof (oid));
-}
-
-void
-oid2in_addr (oid oid[], int len, struct in_addr *addr)
-{
-  int i;
-  u_char *pnt;
-  
-  if (len == 0)
-    return;
-
-  pnt = (u_char *) addr;
-
-  for (i = 0; i < len; i++)
-    *pnt++ = oid[i];
-}
-
-void
-oid_copy_addr (oid oid[], struct in_addr *addr, int len)
-{
-  int i;
-  u_char *pnt;
-  
-  if (len == 0)
-    return;
-
-  pnt = (u_char *) addr;
-
-  for (i = 0; i < len; i++)
-    oid[i] = *pnt++;
-}
-
-int
-oid_compare (oid *o1, int o1_len, oid *o2, int o2_len)
-{
-  int i;
-
-  for (i = 0; i < min (o1_len, o2_len); i++)
-    {
-      if (o1[i] < o2[i])
-	return -1;
-      else if (o1[i] > o2[i])
-	return 1;
-    }
-  if (o1_len < o2_len)
-    return -1;
-  if (o1_len > o2_len)
-    return 1;
-
-  return 0;
-}
-
 static int
 oid_compare_part (oid *o1, int o1_len, oid *o2, int o2_len)
 {
@@ -473,7 +456,7 @@
                   if (write_method)
                     {
                       return (*write_method)(action, val, val_type, val_len,
-					     statP, suffix, suffix_len, v);
+					     statP, suffix, suffix_len);
                     }
                   else
                     {
@@ -1354,32 +1337,6 @@
   return 0;
 }
 
-int
-smux_header_generic (struct variable *v, oid *name, size_t *length, int exact,
-		     size_t *var_len, WriteMethod **write_method)
-{
-  oid fulloid[MAX_OID_LEN];
-  int ret;
-
-  oid_copy (fulloid, v->name, v->namelen);
-  fulloid[v->namelen] = 0;
-  /* Check against full instance. */
-  ret = oid_compare (name, *length, fulloid, v->namelen + 1);
-
-  /* Check single instance. */
-  if ((exact && (ret != 0)) || (!exact && (ret >= 0)))
-	return MATCH_FAILED;
-
-  /* In case of getnext, fill in full instance. */
-  memcpy (name, fulloid, (v->namelen + 1) * sizeof (oid));
-  *length = v->namelen + 1;
-
-  *write_method = 0;
-  *var_len = sizeof(long);    /* default to 'long' results */
-
-  return MATCH_SUCCEEDED;
-}
-
 static int
 smux_peer_default (void)
 {