RPKI: load SSH Library using dlopen function

lib/Modules

@@ -31,3 +31,5 @@ event.h
 checksum.c
 checksum.h
 alloca.h
+libssh.c
+libssh.h

lib/libssh.c

@@ -0,0 +1,126 @@
+/*
+ *	BIRD -- Mockup of SSH Library for loading LibSSH using dlopen
+ *
+ *	(c) 2015 CZ.NIC
+ *
+ *	This file was part of SSH Library: http://www.libssh.org/
+ *	(c) 2003-2009 by Aris Adamantiadis (SSH Library)
+ *
+ *	Can be freely distributed and used under the terms of the GNU GPL.
+ */
+
+#include <dlfcn.h>
+#include "nest/bird.h"
+#include "lib/libssh.h"
+
+#define FILENAME_OF_SHARED_OBJECT_LIBSSH "libssh.so"
+
+static void *libssh;
+
+/*
+ * @return NULL if success
+ * @return string with error if failed
+ */
+const char *
+load_libssh(void)
+{
+  char *err_buf;
+
+  libssh = dlopen(FILENAME_OF_SHARED_OBJECT_LIBSSH, RTLD_LAZY);
+  if (!libssh)
+  {
+    /* This would be probably often repeated problem */
+    char *help_msg = "You have to install libssh library.";
+    err_buf = mb_alloc(&root_pool, 512);
+    bsnprintf(err_buf, 512, "%s. %s", dlerror(), help_msg);
+    return err_buf;
+  }
+
+  dlerror(); /* Clear any existing error */
+
+  ssh_new = (ssh_session (*)(void)) dlsym(libssh, "ssh_new");
+  if ((err_buf = dlerror()) != NULL)
+    return err_buf;
+
+  ssh_set_blocking = (void (*)(ssh_session, int)) dlsym(libssh, "ssh_set_blocking");
+  if ((err_buf = dlerror()) != NULL)
+    return err_buf;
+
+  ssh_options_set = (int (*)(ssh_session, enum ssh_options_e, const void *)) dlsym(libssh, "ssh_options_set");
+  if ((err_buf = dlerror()) != NULL)
+    return err_buf;
+
+  ssh_connect = (int (*)(ssh_session)) dlsym(libssh, "ssh_connect");
+  if ((err_buf = dlerror()) != NULL)
+    return err_buf;
+
+  ssh_get_fd = (socket_t (*)(ssh_session)) dlsym(libssh, "ssh_get_fd");
+  if ((err_buf = dlerror()) != NULL)
+    return err_buf;
+
+  ssh_is_server_known = (int (*)(ssh_session)) dlsym(libssh, "ssh_is_server_known");
+  if ((err_buf = dlerror()) != NULL)
+    return err_buf;
+
+  ssh_userauth_publickey_auto = (int (*)(ssh_session, const char *, const char *)) dlsym(libssh, "ssh_userauth_publickey_auto");
+  if ((err_buf = dlerror()) != NULL)
+    return err_buf;
+
+  ssh_get_error = (const char * (*)(void *)) dlsym(libssh, "ssh_get_error");
+  if ((err_buf = dlerror()) != NULL)
+    return err_buf;
+
+  ssh_get_error_code = (int (*)(void *)) dlsym(libssh, "ssh_get_error_code");
+  if ((err_buf = dlerror()) != NULL)
+    return err_buf;
+
+  ssh_disconnect = (void (*)(ssh_session)) dlsym(libssh, "ssh_disconnect");
+  if ((err_buf = dlerror()) != NULL)
+    return err_buf;
+
+  ssh_free = (void (*)(ssh_session)) dlsym(libssh, "ssh_free");
+  if ((err_buf = dlerror()) != NULL)
+    return err_buf;
+
+  ssh_channel_new = (ssh_channel (*)(ssh_session)) dlsym(libssh, "ssh_channel_new");
+  if ((err_buf = dlerror()) != NULL)
+    return err_buf;
+
+  ssh_channel_is_open = (int (*)(ssh_channel)) dlsym(libssh, "ssh_channel_is_open");
+  if ((err_buf = dlerror()) != NULL)
+    return err_buf;
+
+  ssh_channel_close = (int (*)(ssh_channel)) dlsym(libssh, "ssh_channel_close");
+  if ((err_buf = dlerror()) != NULL)
+    return err_buf;
+
+  ssh_channel_free = (void (*)(ssh_channel)) dlsym(libssh, "ssh_channel_free");
+  if ((err_buf = dlerror()) != NULL)
+    return err_buf;
+
+  ssh_channel_open_session = (int (*)(ssh_channel)) dlsym(libssh, "ssh_channel_open_session");
+  if ((err_buf = dlerror()) != NULL)
+    return err_buf;
+
+  ssh_channel_request_subsystem = (int (*)(ssh_channel, const char *)) dlsym(libssh, "ssh_channel_request_subsystem");
+  if ((err_buf = dlerror()) != NULL)
+    return err_buf;
+
+  ssh_channel_read_nonblocking = (int (*)(ssh_channel, void *, uint32_t, int)) dlsym(libssh, "ssh_channel_read_nonblocking");
+  if ((err_buf = dlerror()) != NULL)
+    return err_buf;
+
+  ssh_channel_is_eof = (int (*)(ssh_channel)) dlsym(libssh, "ssh_channel_is_eof");
+  if ((err_buf = dlerror()) != NULL)
+    return err_buf;
+
+  ssh_channel_select = (int (*)(ssh_channel *, ssh_channel *, ssh_channel *, struct timeval *)) dlsym(libssh, "ssh_channel_select");
+  if ((err_buf = dlerror()) != NULL)
+    return err_buf;
+
+  ssh_channel_write = (int (*)(ssh_channel, const void *, uint32_t)) dlsym(libssh, "ssh_channel_write");
+  if ((err_buf = dlerror()) != NULL)
+    return err_buf;
+
+  return NULL;
+}

lib/libssh.h

@@ -0,0 +1,133 @@
+/*
+ *	BIRD -- Mockup headers of SSH Library for loading LibSSH using dlopen
+ *
+ *	(c) 2015 CZ.NIC
+ *
+ *	This file was part of SSH Library: http://www.libssh.org/
+ *	(c) 2003-2009 by Aris Adamantiadis (SSH Library)
+ *
+ *	Can be freely distributed and used under the terms of the GNU GPL.
+ */
+
+#ifndef _BIRD_LIBSSH_H_
+#define _BIRD_LIBSSH_H_
+
+#include <unistd.h>
+#include <inttypes.h>
+
+typedef struct ssh_session_struct* ssh_session;
+typedef struct ssh_channel_struct* ssh_channel;
+
+/* Error return codes */
+#define SSH_OK 0     /* No error */
+#define SSH_ERROR -1 /* Error of some kind */
+#define SSH_AGAIN -2 /* The nonblocking call must be repeated */
+#define SSH_EOF -127 /* We have already a eof */
+
+enum ssh_server_known_e {
+  SSH_SERVER_ERROR=-1,
+  SSH_SERVER_NOT_KNOWN=0,
+  SSH_SERVER_KNOWN_OK,
+  SSH_SERVER_KNOWN_CHANGED,
+  SSH_SERVER_FOUND_OTHER,
+  SSH_SERVER_FILE_NOT_FOUND
+};
+
+enum ssh_auth_e {
+  SSH_AUTH_SUCCESS=0,
+  SSH_AUTH_DENIED,
+  SSH_AUTH_PARTIAL,
+  SSH_AUTH_INFO,
+  SSH_AUTH_AGAIN,
+  SSH_AUTH_ERROR=-1
+};
+
+enum ssh_error_types_e {
+  SSH_NO_ERROR=0,
+  SSH_REQUEST_DENIED,
+  SSH_FATAL,
+  SSH_EINTR
+};
+
+enum ssh_options_e {
+  SSH_OPTIONS_HOST,
+  SSH_OPTIONS_PORT,
+  SSH_OPTIONS_PORT_STR,
+  SSH_OPTIONS_FD,
+  SSH_OPTIONS_USER,
+  SSH_OPTIONS_SSH_DIR,
+  SSH_OPTIONS_IDENTITY,
+  SSH_OPTIONS_ADD_IDENTITY,
+  SSH_OPTIONS_KNOWNHOSTS,
+  SSH_OPTIONS_TIMEOUT,
+  SSH_OPTIONS_TIMEOUT_USEC,
+  SSH_OPTIONS_SSH1,
+  SSH_OPTIONS_SSH2,
+  SSH_OPTIONS_LOG_VERBOSITY,
+  SSH_OPTIONS_LOG_VERBOSITY_STR,
+  SSH_OPTIONS_CIPHERS_C_S,
+  SSH_OPTIONS_CIPHERS_S_C,
+  SSH_OPTIONS_COMPRESSION_C_S,
+  SSH_OPTIONS_COMPRESSION_S_C,
+  SSH_OPTIONS_PROXYCOMMAND,
+  SSH_OPTIONS_BINDADDR,
+  SSH_OPTIONS_STRICTHOSTKEYCHECK,
+  SSH_OPTIONS_COMPRESSION,
+  SSH_OPTIONS_COMPRESSION_LEVEL,
+  SSH_OPTIONS_KEY_EXCHANGE,
+  SSH_OPTIONS_HOSTKEYS,
+  SSH_OPTIONS_GSSAPI_SERVER_IDENTITY,
+  SSH_OPTIONS_GSSAPI_CLIENT_IDENTITY,
+  SSH_OPTIONS_GSSAPI_DELEGATE_CREDENTIALS,
+  SSH_OPTIONS_HMAC_C_S,
+  SSH_OPTIONS_HMAC_S_C,
+};
+
+enum {
+  /** No logging at all
+   */
+  SSH_LOG_NOLOG=0,
+  /** Only warnings
+   */
+  SSH_LOG_WARNING,
+  /** High level protocol information
+   */
+  SSH_LOG_PROTOCOL,
+  /** Lower level protocol infomations, packet level
+   */
+  SSH_LOG_PACKET,
+  /** Every function path
+   */
+  SSH_LOG_FUNCTIONS
+};
+
+#ifndef socket_t
+typedef int socket_t;
+#endif
+
+ssh_session (*ssh_new)(void);
+void (*ssh_set_blocking)(ssh_session session, int blocking);
+int (*ssh_options_set)(ssh_session session, enum ssh_options_e type, const void *value);
+int (*ssh_connect)(ssh_session session);
+socket_t (*ssh_get_fd)(ssh_session session);
+int (*ssh_is_server_known)(ssh_session session);
+int (*ssh_userauth_publickey_auto)(ssh_session session, const char *username, const char *passphrase);
+const char * (*ssh_get_error)(void *error);
+int (*ssh_get_error_code)(void *error);
+void (*ssh_disconnect)(ssh_session session);
+void (*ssh_free)(ssh_session session);
+
+ssh_channel (*ssh_channel_new)(ssh_session session);
+int (*ssh_channel_is_open)(ssh_channel channel);
+int (*ssh_channel_close)(ssh_channel channel);
+void (*ssh_channel_free)(ssh_channel channel);
+int (*ssh_channel_open_session)(ssh_channel channel);
+int (*ssh_channel_request_subsystem)(ssh_channel channel, const char *subsystem);
+int (*ssh_channel_read_nonblocking)(ssh_channel channel, void *dest, uint32_t count, int is_stderr);
+int (*ssh_channel_is_eof)(ssh_channel channel);
+int (*ssh_channel_select)(ssh_channel *readchans, ssh_channel *writechans, ssh_channel *exceptchans, struct timeval * timeout);
+int (*ssh_channel_write)(ssh_channel channel, const void *data, uint32_t len);
+
+const char *load_libssh(void);
+
+#endif /* _BIRD_LIBSSH_H_ */

lib/socket.h

@@ -10,10 +10,10 @@
 #define _BIRD_SOCKET_H_
 
 #include <errno.h>
-#include <libssh/libssh.h>
 // #include <sys/socket.h>
 
 #include "lib/resource.h"
+#include "lib/libssh.h"
 
 struct ssh_sock {
     char *username;			/* (Required) SSH user name */

proto/rpki/rpki.c

@@ -15,6 +15,9 @@
  * is based on the RTRlib (http://rpki.realmv6.org/). The BIRD takes over
  * |packets.c|, |rtr.c|, |transport.c|, |tcp_transport.c| and |ssh_transport.c| files
  * from RTRlib.
+ *
+ * A SSH transport requires LibSSH library. LibSSH is loading dynamically using dlopen
+ * function.
  */
 
 #undef LOCAL_DEBUG

proto/rpki/ssh_transport.c

@@ -16,6 +16,7 @@
 #include <sys/time.h>
 #include "utils.h"
 #include "ssh_transport.h"
+#include "lib/libssh.h"
 
 #include "rpki.h"
 
@@ -30,6 +31,13 @@ int tr_ssh_open(void *socket)
   struct rpki_cache *cache = ssh_socket->cache;
   struct rpki_proto *p = cache->p;
 
+  const char *err_msg;
+  if((err_msg = load_libssh()) != NULL)
+  {
+    RPKI_ERROR(p, "%s", err_msg);
+    return TR_ERROR;
+  }
+
   sock *s = cache->sk;
   s->type = SK_SSH_ACTIVE;
   s->ssh = mb_allocz(s->pool, sizeof(struct ssh_sock));

proto/rpki/ssh_transport.h

@@ -25,7 +25,6 @@
 
 #ifndef SSH_TRANSPORT_H
 #define SSH_TRANSPORT_H
-#include <libssh/libssh.h>
 #include "transport.h"
 
 /**

sysdep/unix/io.c

@@ -27,7 +27,6 @@
 #include <netinet/tcp.h>
 #include <netinet/udp.h>
 #include <netinet/icmp6.h>
-#include <libssh/libssh.h>
 
 #include "nest/bird.h"
 #include "lib/lists.h"
@@ -36,6 +35,7 @@
 #include "lib/socket.h"
 #include "lib/event.h"
 #include "lib/string.h"
+#include "lib/libssh.h"
 #include "nest/iface.h"
 
 #include "lib/unix.h"