server/: Expose and enhance the bulk-key-derivation protocol.

[tripe] / server / tripe.h

diff --git a/server/tripe.h b/server/tripe.h
index e7c47ecdc44156afdf634407429071b64d9cae36..75ad2f1f5d1e357bfdca8d4e2f9728cfb8336ea4 100644 (file)
--- a/server/tripe.h
+++ b/server/tripe.h
@@ -181,6 +181,16 @@ enum {
   DHFMT_VAR                   /* Variable-width-format, mostly a bad idea */
 };
 
+typedef struct deriveargs {
+  const char *what;                    /* Operation name (hashed) */
+  unsigned f;                          /* Flags */
+#define DF_IN 1u                       /*   Make incoming key */
+#define DF_OUT 2u                      /*   Make outgoing key */
+  const gchash *hc;                    /* Hash class */
+  const octet *k;                      /* Pointer to contributions */
+  size_t x, y, z;                      /* Markers in contributions */
+} deriveargs;
+
 typedef struct bulkalgs {
   const struct bulkops *ops;
 } bulkalgs;
@@ -194,8 +204,6 @@ typedef struct bulkchal {
   size_t tagsz;
 } bulkchal;
 
-struct rawkey;
-
 typedef struct dhops {
   const char *name;
 
@@ -325,9 +333,17 @@ typedef struct bulkops {
         * after which the keys must no longer be used.
         */
 
-  bulkctx *(*genkeys)(const bulkalgs */*a*/, const struct rawkey */*rk*/);
+  bulkctx *(*genkeys)(const bulkalgs */*a*/, const deriveargs */*a*/);
        /* Generate session keys and construct and return an appropriate
-        * context for using them, by calling @ks_derive@.
+        * context for using them.  The offsets @a->x@, @a->y@ and @a->z@
+        * separate the key material into three parts.  Between @a->k@ and
+        * @a->k + a->x@ is `my' contribution to the key material; between
+        * @a->k + a->x@ and @a->k + a->y@ is `your' contribution; and
+        * between @a->k + a->y@ and @a->k + a->z@ is a shared value we made
+        * together.  These are used to construct (up to) two collections of
+        * symmetric keys: one for outgoing messages, the other for incoming
+        * messages.  If @a->x == 0@ (or @a->y == a->x@) then my (or your)
+        * contribution is omitted.
         */
 
   bulkchal *(*genchal)(const bulkalgs */*a*/);
@@ -741,7 +757,7 @@ struct admin {
 #define AF_NOTE 4u                     /* Catch notifications */
 #define AF_WARN 8u                     /* Catch warning messages */
 #ifndef NTRACE
-  #define AF_TRACE 16u                 /* Catch tracing */
+#  define AF_TRACE 16u                 /* Catch tracing */
 #endif
 #define AF_FOREGROUND 32u              /* Quit server when client closes */
 
@@ -939,52 +955,23 @@ extern int kx_init(keyexch */*kx*/, peer */*p*/,
 
 extern void ks_drop(keyset */*ks*/);
 
-/* --- @ks_derivekey@ --- *
- *
- * Arguments:  @octet *k@ = pointer to an output buffer of at least
- *                     @MAXHASHSZ@ bytes
- *             @size_t ksz@ = actual size wanted (for tracing)
- *             @const struct rawkey *rk@ = a raw key, as passed into
- *                     @genkeys@
- *             @int dir@ = direction for the key (@DIR_IN@ or @DIR_OUT@)
- *             @const char *what@ = label for the key (input to derivation)
- *
- * Returns:    ---
- *
- * Use:                Derives a session key, for use on incoming or outgoing data.
- *             This function is part of a private protocol between @ks_gen@
- *             and the bulk crypto transform @genkeys@ operation.
- */
-
-extern void ks_derivekey(octet */*k*/, size_t /*ksz*/,
-                        const struct rawkey */*rk*/,
-                        int /*dir*/, const char */*what*/);
-
 /* --- @ks_gen@ --- *
  *
- * Arguments:  @const void *k@ = pointer to key material
- *             @size_t x, y, z@ = offsets into key material (see below)
+ * Arguments:  @deriveargs *a@ = key derivation parameters (modified)
  *             @peer *p@ = pointer to peer information
  *
  * Returns:    A pointer to the new keyset.
  *
- * Use:                Derives a new keyset from the given key material.  The
- *             offsets @x@, @y@ and @z@ separate the key material into three
- *             parts.  Between the @k@ and @k + x@ is `my' contribution to
- *             the key material; between @k + x@ and @k + y@ is `your'
- *             contribution; and between @k + y@ and @k + z@ is a shared
- *             value we made together.  These are used to construct two
- *             collections of symmetric keys: one for outgoing messages, the
- *             other for incoming messages.
+ * Use:                Derives a new keyset from the given key material.  This will
+ *             set the @what@, @f@, and @hc@ members in @*a@; other members
+ *             must be filled in by the caller.
  *
  *             The new key is marked so that it won't be selected for output
  *             by @ksl_encrypt@.  You can still encrypt data with it by
  *             calling @ks_encrypt@ directly.
  */
 
-extern keyset *ks_gen(const void */*k*/,
-                     size_t /*x*/, size_t /*y*/, size_t /*z*/,
-                     peer */*p*/);
+extern keyset *ks_gen(deriveargs */*a*/, peer */*p*/);
 
 /* --- @ks_activate@ --- *
  *