1 files changed, 175 insertions, 0 deletions

diff --git a/src/cipher.c b/src/cipher.c
new file mode 100644
index 0000000..02960e4
--- /dev/null
+++ b/src/cipher.c
@@ -0,0 +1,175 @@
+/*
+ *  ľAnytun
+ *
+ *  ľAnytun is a tiny implementation of SATP. Unlike Anytun which is a full
+ *  featured implementation ľAnytun has no support for multiple connections
+ *  or synchronisation. It is a small single threaded implementation intended
+ *  to act as a client on small platforms.
+ *  The secure anycast tunneling protocol (satp) defines a protocol used
+ *  for communication between any combination of unicast and anycast
+ *  tunnel endpoints.  It has less protocol overhead than IPSec in Tunnel
+ *  mode and allows tunneling of every ETHER TYPE protocol (e.g.
+ *  ethernet, ip, arp ...). satp directly includes cryptography and
+ *  message authentication based on the methodes used by SRTP.  It is
+ *  intended to deliver a generic, scaleable and secure solution for
+ *  tunneling and relaying of packets of any protocol.
+ *  
+ *
+ *  Copyright (C) 2007-2008 Christian Pointner <equinox@anytun.org>
+ *
+ *  This file is part of ľAnytun.
+ *
+ *  ľAnytun is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 3 as
+ *  published by the Free Software Foundation.
+ *
+ *  ľAnytun is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with ľAnytun. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "datatypes.h"
+
+#include "plain_packet.h"
+#include "encrypted_packet.h"
+
+#include "cipher.h"
+
+#include "log.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+void cipher_init(cipher_t** c, const char* type)
+{
+  if(!c) 
+    return;
+
+  *c = malloc(sizeof(cipher_t));
+  if(!*c)
+    return;
+
+  (*c)->type_ = unknown;
+  if(!strcmp(type, "null"))
+    (*c)->type_ = null;
+  else if(!strcmp(type, "aes-ctr"))
+    (*c)->type_ = aes_ctr;
+  else {
+    log_printf(ERR, "unknown cipher type");
+  }
+
+  (*c)->key_.buf_ = NULL;
+  (*c)->key_.length_ = 0;
+
+  (*c)->salt_.buf_ = NULL;
+  (*c)->salt_.length_ = 0;
+}
+
+void cipher_set_key(cipher_t* c, u_int8_t* key, u_int32_t len)
+{
+  if(!c) 
+    return;
+  if(c->type_ == null)
+    return;
+
+  if(c->key_.buf_)
+    free(c->key_.buf_);
+  c->key_.buf_ = malloc(len);
+  if(!c->key_.buf_)
+    return;
+  memcpy(c->key_.buf_, key, len);
+  c->key_.length_ = len;
+}
+
+void cipher_set_salt(cipher_t* c, u_int8_t* salt, u_int32_t len)
+{
+  if(!c) 
+    return;
+  if(c->type_ == null)
+    return;
+
+  if(c->salt_.buf_)
+    free(c->salt_.buf_);
+  c->salt_.buf_ = malloc(len);
+  if(!c->salt_.buf_)
+    return;
+  memcpy(c->salt_.buf_, salt, len);
+  c->salt_.length_ = len;
+}
+
+void cipher_close(cipher_t** c)
+{
+  if(!c || !(*c))
+    return;
+
+  if((*c)->key_.buf_)
+    free((*c)->key_.buf_);
+  if((*c)->salt_.buf_)
+    free((*c)->salt_.buf_);
+
+  free(*c);
+  *c = NULL;
+}
+
+void cipher_encrypt(cipher_t* c, plain_packet_t* in, encrypted_packet_t* out, seq_nr_t seq_nr, sender_id_t sender_id, mux_t mux)
+{
+  if(!c) 
+    return;
+
+	u_int32_t len;
+  if(c->type_ = null)
+    len = cipher_null_encrypt(plain_packet_get_packet(in), plain_packet_get_length(in), 
+                              encrypted_packet_get_payload(out), encrypted_packet_get_payload_length(out));
+  else if(c->type_ = aes_ctr)
+    len = cipher_aesctr_encrypt(plain_packet_get_packet(in), plain_packet_get_length(in), 
+                                encrypted_packet_get_payload(out), encrypted_packet_get_payload_length(out),
+                                seq_nr, sender_id, mux);
+  else {
+    log_printf(ERR, "unknown cipher type");
+    return;
+  }
+
+	encrypted_packet_set_sender_id(out, sender_id);
+  encrypted_packet_set_seq_nr(out, seq_nr);
+  encrypted_packet_set_mux(out, mux);
+
+  encrypted_packet_set_payload_length(out, len);
+}
+
+void cipher_decrypt(cipher_t* c, encrypted_packet_t* in, plain_packet_t* out)
+{
+  if(!c) 
+    return;
+
+	u_int32_t len;
+  if(c->type_ = null)
+    len = cipher_null_decrypt(encrypted_packet_get_payload(in), encrypted_packet_get_payload_length(in),
+                              plain_packet_get_packet(out), plain_packet_get_length(out));
+  else if(c->type_ = aes_ctr)
+    len = cipher_aesctr_decrypt(encrypted_packet_get_payload(in), encrypted_packet_get_payload_length(in),
+                                plain_packet_get_packet(out), plain_packet_get_length(out), 
+                                encrypted_packet_get_seq_nr(in), encrypted_packet_get_sender_id(in), 
+                                encrypted_packet_get_mux(in));
+  else {
+    log_printf(ERR, "unknown cipher type");
+    return;
+  }
+  
+	plain_packet_set_length(out, len);
+}
+
+u_int32_t cipher_null_encrypt(u_int8_t* in, u_int32_t ilen, u_int8_t* out, u_int32_t olen)
+{
+	memcpy(out, in, (ilen < olen) ? ilen : olen);
+  return (ilen < olen) ? ilen : olen;
+}
+
+u_int32_t cipher_null_decrypt(u_int8_t* in, u_int32_t ilen, u_int8_t* out, u_int32_t olen)
+{
+	memcpy(out, in, (ilen < olen) ? ilen : olen);
+  return (ilen < olen) ? ilen : olen;
+}