Expose key generation functions in testcrypt.

They're not much use for 'real' key generation, since like all the
other randomness-using testcrypt functions, they need you to have
explicitly queued up some random data. But for generating keys for
test purposes, they have the great virtue that they deliver the key in
the internal format, where we can generate all the various public and
private blobs from it as well as the on-disk formats.

A minor change to one of the keygen functions itself: rsa_generate now
fills in the 'bits' and 'bytes' fields of the returned RSAKey, without
which it didn't actually work to try to generate a public blob from
it. (We'd never noticed before, because no previous client of
rsa_generate even tried that.)

testcrypt.c

@@ -920,6 +920,50 @@ mp_int *primegen_wrapper(
 }
 #define primegen primegen_wrapper
 
+RSAKey *rsa1_generate(int bits)
+{
+    RSAKey *rsakey = snew(RSAKey);
+    rsa_generate(rsakey, bits, no_progress, NULL);
+    rsakey->comment = NULL;
+    return rsakey;
+}
+
+ssh_key *rsa_generate_wrapper(int bits)
+{
+    return &rsa1_generate(bits)->sshk;
+}
+#define rsa_generate rsa_generate_wrapper
+
+ssh_key *dsa_generate_wrapper(int bits)
+{
+    struct dss_key *dsskey = snew(struct dss_key);
+    dsa_generate(dsskey, bits, no_progress, NULL);
+    return &dsskey->sshk;
+}
+#define dsa_generate dsa_generate_wrapper
+
+ssh_key *ecdsa_generate_wrapper(int bits)
+{
+    struct ecdsa_key *ek = snew(struct ecdsa_key);
+    if (!ecdsa_generate(ek, bits, no_progress, NULL)) {
+        sfree(ek);
+        return NULL;
+    }
+    return &ek->sshk;
+}
+#define ecdsa_generate ecdsa_generate_wrapper
+
+ssh_key *eddsa_generate_wrapper(int bits)
+{
+    struct eddsa_key *ek = snew(struct eddsa_key);
+    if (!eddsa_generate(ek, bits, no_progress, NULL)) {
+        sfree(ek);
+        return NULL;
+    }
+    return &ek->sshk;
+}
+#define eddsa_generate eddsa_generate_wrapper
+
 #define VALTYPE_TYPEDEF(n,t,f)                  \
     typedef t TD_val_##n;                       \
     typedef t *TD_out_val_##n;