Made the server DH asynchronous.

It still needs testing and cleanup, it was done with less
care than the client-side.
The socket listening and connexion is still synchronous

include/libssh/priv.h

@@ -245,6 +245,9 @@ int gettimeofday(struct timeval *__p, void *__t);
 char *dir_expand_dup(ssh_session session, const char *value, int allowsshdir);
 int ssh_options_set_algo(ssh_session session, int algo, const char *list);
 
+/* server.c */
+SSH_PACKET_CALLBACK(ssh_packet_kexdh_init);
+
 /** Free memory space */
 #define SAFE_FREE(x) do { if ((x) != NULL) {free(x); x=NULL;} } while(0)
 

include/libssh/session.h

@@ -43,6 +43,12 @@ enum ssh_session_state_e {
 	SSH_SESSION_STATE_ERROR
 };
 
+enum ssh_dh_state_e {
+  DH_STATE_INIT,
+  DH_STATE_INIT_SENT,
+  DH_STATE_NEWKEYS_SENT,
+  DH_STATE_FINISHED
+};
 
 struct ssh_session_struct {
     struct error_struct error;