X-Git-Url: https://www.tinc-vpn.org/git/browse?p=tinc;a=blobdiff_plain;f=src%2Fprotocol.c;h=e9ee9665de3cdd39a600d40f2028c2ea89709a8e;hp=0b3563efd44d32fcd62e5630cd41a388f1e5eda3;hb=24a2c7e51a0b080c4bdb55f697b3f0458ebc3fb1;hpb=447a43d63960802a7a29201c512246be11eb9c94

diff --git a/src/protocol.c b/src/protocol.c
index 0b3563ef..e9ee9665 100644
--- a/src/protocol.c
+++ b/src/protocol.c
@@ -17,7 +17,7 @@
     along with this program; if not, write to the Free Software
     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 
-    $Id: protocol.c,v 1.28.4.75 2001/01/07 20:19:31 guus Exp $
+    $Id: protocol.c,v 1.28.4.106 2001/09/24 14:12:00 guus Exp $
 */
 
 #include "config.h"
@@ -31,6 +31,7 @@
 #include <unistd.h>
 #include <stdio.h>
 #include <stdarg.h>
+#include <errno.h>
 
 #include <utils.h>
 #include <xalloc.h>
@@ -39,25 +40,14 @@
 
 #include <netinet/in.h>
 
-#ifdef HAVE_OPENSSL_SHA_H
-# include <openssl/sha.h>
-#else
-# include <sha.h>
-#endif
-
-#ifdef HAVE_OPENSSL_RAND_H
-# include <openssl/rand.h>
-#else
-# include <rand.h>
-#endif
+#include <openssl/sha.h>
+#include <openssl/rand.h>
+#include <openssl/evp.h>
 
-#ifdef HAVE_OPENSSL_EVP_H
-# include <openssl/evp.h>
-#else
-# include <evp.h>
+#ifndef HAVE_RAND_PSEUDO_BYTES
+#define RAND_pseudo_bytes RAND_bytes
 #endif
 
-
 #include "conf.h"
 #include "net.h"
 #include "netutl.h"
@@ -67,6 +57,8 @@
 
 #include "system.h"
 
+int mykeyused = 0;
+
 int check_id(char *id)
 {
   int i;
@@ -103,11 +95,15 @@ cp
       return -1;
     }
 
-  len++;
-
   if(debug_lvl >= DEBUG_PROTOCOL)
-    syslog(LOG_DEBUG, _("Sending %s to %s (%s)"), request_name[request], cl->name, cl->hostname);
+    {
+      if(debug_lvl >= DEBUG_META)
+        syslog(LOG_DEBUG, _("Sending %s to %s (%s): %s"), request_name[request], cl->name, cl->hostname, buffer);
+      else
+        syslog(LOG_DEBUG, _("Sending %s to %s (%s)"), request_name[request], cl->name, cl->hostname);
+    }
 
+  buffer[len++] = '\n';
 cp
   return send_meta(cl, buffer, len);
 }
@@ -115,20 +111,31 @@ cp
 int receive_request(connection_t *cl)
 {
   int request;
-cp  
+cp
   if(sscanf(cl->buffer, "%d", &request) == 1)
     {
-      if((request < 0) || (request > 255) || (request_handlers[request] == NULL))
+      if((request < 0) || (request >= LAST) || (request_handlers[request] == NULL))
         {
-          syslog(LOG_ERR, _("Unknown request from %s (%s)"),
-		 cl->name, cl->hostname);
+          if(debug_lvl >= DEBUG_META)
+            syslog(LOG_DEBUG, _("Unknown request from %s (%s): %s"),
+	           cl->name, cl->hostname, cl->buffer);
+          else
+            syslog(LOG_ERR, _("Unknown request from %s (%s)"),
+                   cl->name, cl->hostname);
+                   
           return -1;
         }
       else
         {
           if(debug_lvl >= DEBUG_PROTOCOL)
-            syslog(LOG_DEBUG, _("Got %s from %s (%s)"),
-		   request_name[request], cl->name, cl->hostname);
+            {
+              if(debug_lvl >= DEBUG_META)
+                syslog(LOG_DEBUG, _("Got %s from %s (%s): %s"),
+	               request_name[request], cl->name, cl->hostname, cl->buffer);
+              else
+                syslog(LOG_DEBUG, _("Got %s from %s (%s)"),
+		       request_name[request], cl->name, cl->hostname);
+            }
 	}
 
       if((cl->allow_request != ALL) && (cl->allow_request != request))
@@ -155,51 +162,20 @@ cp
   return 0;
 }
 
-/* Connection protocol:
-
-   Client               Server
-   send_id(u)
-                        send_challenge(R)
-   send_chal_reply(H)
-                        send_id(u)
-   send_challenge(R)
-                        send_chal_reply(H)
-   ---------------------------------------
-   send_metakey(R)
-                        send_metakey(R)
-   ---------------------------------------
-   send_ack(u)
-                        send_ack(u)
-   ---------------------------------------
-   Other requests(E)...
-
-   (u) Unencrypted,
-   (R) RSA,
-   (H) SHA1,
-   (E) Encrypted with symmetric cipher.
-
-   Part of the challenge is directly used to set the symmetric cipher
-   key and the initial vector.  Since a man-in-the-middle cannot
-   decrypt the RSA challenges, this means that he cannot get or forge
-   the key for the symmetric cipher.
-*/
+/* The authentication protocol is described in detail in doc/SECURITY2,
+   the rest will be described in doc/PROTOCOL. */
 
 int send_id(connection_t *cl)
 {
-cp
-  cl->allow_request = CHALLENGE;
 cp
   return send_request(cl, "%d %s %d %lx %hd", ID, myself->name, myself->protocol_version, myself->options, myself->port);
 }
 
 int id_h(connection_t *cl)
 {
-  connection_t *old;
-  unsigned short int port;
   char name[MAX_STRING_SIZE];
-  avl_node_t *node;
 cp
-  if(sscanf(cl->buffer, "%*d "MAX_STRING" %d %lx %hd", name, &cl->protocol_version, &cl->options, &port) != 4)
+  if(sscanf(cl->buffer, "%*d "MAX_STRING" %d %lx %hd", name, &cl->protocol_version, &cl->options, &cl->port) != 4)
     {
        syslog(LOG_ERR, _("Got bad ID from %s"), cl->hostname);
        return -1;
@@ -224,6 +200,9 @@ cp
   
   /* Copy string to cl */
   
+  if(cl->name)
+    free(cl->name);
+    
   cl->name = xstrdup(name);
 
   /* Load information about peer */
@@ -234,41 +213,116 @@ cp
       return -1;
     }
 
-  /* First check if the host we connected to is already in our
-     connection list. If so, we are probably making a loop, which
-     is not desirable.
+  /* Read in the public key, so that we can send a metakey */
+
+  if(read_rsa_public_key(cl))
+    return -1;
+
+  cl->allow_request = METAKEY;
+cp
+  return send_metakey(cl);
+}
+
+int ack_h(connection_t *cl)
+{
+  config_t const *cfg;
+  connection_t *old, *p;
+  subnet_t *subnet;
+  avl_node_t *node, *node2;
+cp
+  /* Okay, before we active the connection, we check if there is another entry
+     in the connection list with the same name. If so, it presumably is an
+     old connection that has timed out but we don't know it yet.
    */
 
-  if(cl->status.outgoing)
+  if((old = lookup_id(cl->name)))
     {
-      if((old = lookup_id(cl->name)))
+      if(debug_lvl >= DEBUG_CONNECTIONS)
+        syslog(LOG_NOTICE, _("Removing old connection for %s at %s in favour of new connection at %s"),
+               old->name, old->hostname, cl->hostname);
+      if(old->status.outgoing)
         {
-          if(debug_lvl >= DEBUG_CONNECTIONS)
-            syslog(LOG_NOTICE, _("Uplink %s (%s) is already in our connection list"), cl->name, cl->hostname);
-          cl->status.outgoing = 0;
-          old->status.outgoing = 1;
-          terminate_connection(cl);
-          return 0;
+          cl->status.outgoing = 1;
+          old->status.outgoing = 0;
         }
+      terminate_connection(old, 0);
+      return 0;
     }
     
-  /* Now we can add the name to the id tree */
+  /* Also check if no other tinc daemon uses the same IP and port for UDP traffic */
   
-  id_add(cl);
+  old = avl_search(active_tree, cl);
+  if(old)
+  {
+    syslog(LOG_ERR, _("%s is listening on %s:%hd, which is already in use by %s!"),
+           cl->name, cl->hostname, cl->port, old->name);
+    return -1;
+  }
+    
+  /* Activate this connection */
+
+  cl->allow_request = ALL;
+  cl->nexthop = cl;
+  cl->lastbutonehop = myself;
+  cl->cipher_pkttype = EVP_bf_cbc();
+  cl->cipher_pktkeylength = cl->cipher_pkttype->key_len + cl->cipher_pkttype->iv_len;
+
+  active_add(cl);
 
-  /* And uhr... cl->port just changed so we have to unlink it from the connection tree and re-insert... */
+  if(debug_lvl >= DEBUG_CONNECTIONS)
+    syslog(LOG_NOTICE, _("Connection with %s (%s) activated"), cl->name, cl->hostname);
+
+  if(cl->status.outgoing)
+    seconds_till_retry = 5;	/* Reset retry timeout */
+cp
+  /* Check some options */
   
-  node = avl_unlink(connection_tree, cl);
-  cl->port = port;
-  avl_insert_node(connection_tree, node);
+  if((cfg = get_config_val(cl->config, config_indirectdata)))
+    {
+      if(cfg->data.val == stupid_true)
+        cl->options |= OPTION_INDIRECT;
+    }
 
-  /* Read in the public key, so that we can send a challenge */
+  if((cfg = get_config_val(cl->config, config_tcponly)))
+    {
+      if(cfg->data.val == stupid_true)
+        cl->options |= OPTION_TCPONLY;
+    }
 
-  if(read_rsa_public_key(cl))
-    return -1;
+  /* Send him our subnets */
+  
+  for(node = myself->subnet_tree->head; node; node = node->next)
+    {
+      subnet = (subnet_t *)node->data;
+      send_add_subnet(cl, subnet);
+    }
+
+  /* And send him all the hosts and their subnets we know... */
+  
+  for(node = active_tree->head; node; node = node->next)
+    {
+      p = (connection_t *)node->data;
+      
+      if(p != cl)
+        {
+          /* Notify others of this connection */
 
+          if(p->status.meta)
+            send_add_host(p, cl);
+
+          /* Notify new connection of everything we know */
+
+          send_add_host(cl, p);
+
+          for(node2 = p->subnet_tree->head; node2; node2 = node2->next)
+            {
+              subnet = (subnet_t *)node2->data;
+              send_add_subnet(cl, subnet);
+            }
+        }
+    }
 cp
-  return send_challenge(cl);
+  return 0;
 }
 
 int send_challenge(connection_t *cl)
@@ -276,6 +330,8 @@ int send_challenge(connection_t *cl)
   char *buffer;
   int len, x;
 cp
+  /* CHECKME: what is most reasonable value for len? */
+
   len = RSA_size(cl->rsa_key);
 
   /* Allocate buffers for the challenge */
@@ -291,32 +347,15 @@ cp
 
   RAND_bytes(cl->hischallenge, len);
 
-  cl->hischallenge[0] &= 0x7F;	/* Somehow if the first byte is more than 0xD0 or something like that, decryption fails... */
 cp
-  if(debug_lvl >= DEBUG_SCARY_THINGS)
-    {
-      bin2hex(cl->hischallenge, buffer, len);
-      buffer[len*2] = '\0';
-      syslog(LOG_DEBUG, _("Generated random challenge (unencrypted): %s"), buffer);
-    }
-
-  /* Encrypt the random data */
+  /* Convert to hex */
 
-  if(RSA_public_encrypt(len, cl->hischallenge, buffer, cl->rsa_key, RSA_NO_PADDING) != len)	/* NO_PADDING because the message size equals the RSA key size and it is totally random */
-    {
-      syslog(LOG_ERR, _("Error during encryption of challenge for %s (%s)"), cl->name, cl->hostname);
-      free(buffer);
-      return -1;
-    }
-cp
-  /* Convert the encrypted random data to a hexadecimal formatted string */
-
-  bin2hex(buffer, buffer, len);
+  bin2hex(cl->hischallenge, buffer, len);
   buffer[len*2] = '\0';
+
 cp
   /* Send the challenge */
 
-  cl->allow_request = CHAL_REPLY;
   x = send_request(cl, "%d %s", CHALLENGE, buffer);
   free(buffer);
 cp
@@ -351,22 +390,9 @@ cp
 
   /* Convert the challenge from hexadecimal back to binary */
 
-  hex2bin(buffer,buffer,len);
-
-  /* Decrypt the challenge */
-  
-  if(RSA_private_decrypt(len, buffer, cl->mychallenge, myself->rsa_key, RSA_NO_PADDING) != len)	/* See challenge() */
-    {
-      syslog(LOG_ERR, _("Error during encryption of challenge for %s (%s)"), cl->name, cl->hostname);
-      return -1;
-    }
+  hex2bin(buffer,cl->mychallenge,len);
 
-  if(debug_lvl >= DEBUG_SCARY_THINGS)
-    {
-      bin2hex(cl->mychallenge, buffer, len);
-      buffer[len*2] = '\0';
-      syslog(LOG_DEBUG, _("Received random challenge (unencrypted): %s"), buffer);
-    }
+  cl->allow_request = CHAL_REPLY;
 
   /* Rest is done by send_chal_reply() */
 cp
@@ -394,11 +420,6 @@ cp
 
   /* Send the reply */
 
-  if(cl->status.outgoing)
-    cl->allow_request = ID;
-  else
-    cl->allow_request = METAKEY;
-
 cp
   return send_request(cl, "%d %s", CHAL_REPLY, hash);
 }
@@ -444,16 +465,11 @@ cp
       return -1;
     }
 
-
   /* Identity has now been positively verified.
-     If we are accepting this new connection, then send our identity,
-     if we are making this connecting, acknowledge.
+     ack_h() handles the rest from now on.
    */
 cp
-  if(cl->status.outgoing)
-      return send_metakey(cl);
-  else
-      return send_id(cl);
+  return ack_h(cl);
 }
 
 int send_metakey(connection_t *cl)
@@ -477,8 +493,18 @@ cp
 
   RAND_bytes(cl->cipher_outkey, len);
 
-  cl->cipher_outkey[0] &= 0x7F;	/* FIXME: Somehow if the first byte is more than 0xD0 or something like that, decryption fails... */
-
+  /* The message we send must be smaller than the modulus of the RSA key.
+     By definition, for a key of k bits, the following formula holds:
+     
+       2^(k-1) <= modulus < 2^(k)
+     
+     Where ^ means "to the power of", not "xor".
+     This means that to be sure, we must choose our message < 2^(k-1).
+     This can be done by setting the most significant bit to zero.
+  */
+  
+  cl->cipher_outkey[0] &= 0x7F;
+  
   if(debug_lvl >= DEBUG_SCARY_THINGS)
     {
       bin2hex(cl->cipher_outkey, buffer, len);
@@ -486,9 +512,14 @@ cp
       syslog(LOG_DEBUG, _("Generated random meta key (unencrypted): %s"), buffer);
     }
 
-  /* Encrypt the random data */
+  /* Encrypt the random data
+  
+     We do not use one of the PKCS padding schemes here.
+     This is allowed, because we encrypt a totally random string
+     with a length equal to that of the modulus of the RSA key.
+  */
   
-  if(RSA_public_encrypt(len, cl->cipher_outkey, buffer, cl->rsa_key, RSA_NO_PADDING) != len)	/* NO_PADDING because the message size equals the RSA key size and it is totally random */
+  if(RSA_public_encrypt(len, cl->cipher_outkey, buffer, cl->rsa_key, RSA_NO_PADDING) != len)
     {
       syslog(LOG_ERR, _("Error during encryption of meta key for %s (%s)"), cl->name, cl->hostname);
       free(buffer);
@@ -502,15 +533,16 @@ cp
 
   /* Send the meta key */
 
-  if(cl->status.outgoing)
-    cl->allow_request = METAKEY;
-  else
-    cl->allow_request = ACK;
-    
   x = send_request(cl, "%d %s", METAKEY, buffer);
   free(buffer);
 
-  EVP_EncryptInit(cl->cipher_outctx, EVP_bf_cfb(), cl->cipher_outkey, cl->cipher_outkey + EVP_bf_cfb()->key_len);
+  /* Further outgoing requests are encrypted with the key we just generated */
+
+  EVP_EncryptInit(cl->cipher_outctx, EVP_bf_cfb(),
+                  cl->cipher_outkey + len - EVP_bf_cfb()->key_len,
+                  cl->cipher_outkey + len - EVP_bf_cfb()->key_len - EVP_bf_cfb()->iv_len);
+
+  cl->status.encryptout = 1;
 cp
   return x;
 }
@@ -563,112 +595,17 @@ cp
       syslog(LOG_DEBUG, _("Received random meta key (unencrypted): %s"), buffer);
     }
 
-  EVP_DecryptInit(cl->cipher_inctx, EVP_bf_cfb(), cl->cipher_inkey, cl->cipher_inkey + EVP_bf_cfb()->key_len);
-  
-cp
-  if(cl->status.outgoing)
-    return send_ack(cl);
-  else
-    return send_metakey(cl);
-}
-
-int send_ack(connection_t *cl)
-{
-  int x;
-cp
-  if(cl->status.outgoing)
-    cl->allow_request = ACK;
-
-  x = send_request(cl, "%d", ACK);
-  cl->status.encryptout = 1;
-cp
-  return x;
-}
-
-int ack_h(connection_t *cl)
-{
-  config_t const *cfg;
-  connection_t *old, *p;
-  subnet_t *subnet;
-  avl_node_t *node, *node2;
-cp
-  /* Okay, before we active the connection, we check if there is another entry
-     in the connection list with the same name. If so, it presumably is an
-     old connection that has timed out but we don't know it yet.
-   */
+  /* All incoming requests will now be encrypted. */
 
-  while((old = lookup_id(cl->name)))
-    {
-      if(debug_lvl >= DEBUG_CONNECTIONS)
-        syslog(LOG_NOTICE, _("Removing old entry for %s at %s in favour of new connection from %s"),
-        cl->name, old->hostname, cl->hostname);
-
-      terminate_connection(old);
-    }
-
-  /* Activate this connection */
-
-  cl->allow_request = ALL;
-  cl->status.active = 1;
-  cl->status.decryptin = 1;
-  cl->nexthop = cl;
-  cl->cipher_pkttype = EVP_bf_cfb();
-  cl->cipher_pktkeylength = cl->cipher_pkttype->key_len + cl->cipher_pkttype->iv_len;
-
-  if(debug_lvl >= DEBUG_CONNECTIONS)
-    syslog(LOG_NOTICE, _("Connection with %s (%s) activated"), cl->name, cl->hostname);
-
-cp
-  if(!cl->status.outgoing)
-    send_ack(cl);
-
-  /* Check some options */
+  EVP_DecryptInit(cl->cipher_inctx, EVP_bf_cfb(),
+                  cl->cipher_inkey + len - EVP_bf_cfb()->key_len,
+                  cl->cipher_inkey + len - EVP_bf_cfb()->key_len - EVP_bf_cfb()->iv_len);
   
-  if((cfg = get_config_val(cl->config, config_indirectdata)))
-    {
-      if(cfg->data.val == stupid_true)
-        cl->options |= OPTION_INDIRECT;
-    }
-
-  if((cfg = get_config_val(cl->config, config_tcponly)))
-    {
-      if(cfg->data.val == stupid_true)
-        cl->options |= OPTION_TCPONLY;
-    }
-
-  /* Send him our subnets */
-  
-  for(node = myself->subnet_tree->head; node; node = node->next)
-    {
-      subnet = (subnet_t *)node->data;
-      send_add_subnet(cl, subnet);
-    }
-  /* And send him all the hosts and their subnets we know... */
-  
-  for(node = connection_tree->head; node; node = node->next)
-    {
-      p = (connection_t *)node->data;
-      
-      if(p != cl && p->status.active)
-        {
-          /* Notify others of this connection */
-
-          if(p->status.meta)
-            send_add_host(p, cl);
-
-          /* Notify new connection of everything we know */
-
-          send_add_host(cl, p);
+  cl->status.decryptin = 1;
 
-          for(node2 = p->subnet_tree->head; node2; node2 = node2->next)
-            {
-              subnet = (subnet_t *)node2->data;
-              send_add_subnet(cl, subnet);
-            }
-        }
-    }  
+  cl->allow_request = CHALLENGE;
 cp
-  return 0;
+  return send_challenge(cl);
 }
 
 /* Address and subnet information exchange */
@@ -679,10 +616,7 @@ int send_add_subnet(connection_t *cl, subnet_t *subnet)
   char *netstr;
   char *owner;
 cp
-  if(cl->options & OPTION_INDIRECT)
-    owner = myself->name;
-  else
-    owner = subnet->owner->name;
+  owner = subnet->owner->name;
 
   x = send_request(cl, "%d %s %s", ADD_SUBNET,
                       owner, netstr = net2str(subnet));
@@ -749,7 +683,7 @@ cp
   for(node = connection_tree->head; node; node = node->next)
     {
       p = (connection_t *)node->data;
-      if(p->status.meta && p->status.active && p!= cl)
+      if(p->status.active && p!= cl)
         send_add_subnet(p, subnet);
     }
 cp
@@ -762,10 +696,7 @@ int send_del_subnet(connection_t *cl, subnet_t *subnet)
   char *netstr;
   char *owner;
 cp
-  if(cl->options & OPTION_INDIRECT)
-    owner = myself->name;
-  else
-    owner = subnet->owner->name;
+  owner = subnet->owner->name;
 
   x = send_request(cl, "%d %s %s", DEL_SUBNET, owner, netstr = net2str(subnet));
   free(netstr);
@@ -833,7 +764,7 @@ cp
   for(node = connection_tree->head; node; node = node->next)
     {
       p = (connection_t *)node->data;
-      if(p->status.meta && p->status.active && p!= cl)
+      if(p->status.active && p!= cl)
         send_del_subnet(p, subnet);
     }
 cp
@@ -845,20 +776,19 @@ cp
 int send_add_host(connection_t *cl, connection_t *other)
 {
 cp
-  if(!(cl->options & OPTION_INDIRECT))
-    return send_request(cl, "%d %s %lx:%d %lx", ADD_HOST,
-                      other->name, other->address, other->port, other->options);
+  return send_request(cl, "%d %s %lx:%d %lx %s", ADD_HOST,
+                      other->name, other->address, other->port, other->options, other->lastbutonehop->name);
 }
 
 int add_host_h(connection_t *cl)
 {
   connection_t *old, *new, *p;
-  char name[MAX_STRING_SIZE];
+  char name[MAX_STRING_SIZE], lastbutone[MAX_STRING_SIZE];
   avl_node_t *node;
 cp
   new = new_connection();
 
-  if(sscanf(cl->buffer, "%*d "MAX_STRING" %lx:%d %lx", name, &new->address, &new->port, &new->options) != 4)
+  if(sscanf(cl->buffer, "%*d "MAX_STRING" %lx:%hd %lx "MAX_STRING, name, &new->address, &new->port, &new->options, lastbutone) != 5)
     {
        syslog(LOG_ERR, _("Got bad ADD_HOST from %s (%s)"), cl->name, cl->hostname);
        return -1;
@@ -873,62 +803,75 @@ cp
       return -1;
     }
 
+  if(check_id(lastbutone))
+    {
+      syslog(LOG_ERR, _("Got bad ADD_HOST from %s (%s): invalid lastbutone name"), cl->name, cl->hostname);
+      free_connection(new);
+      return -1;
+    }
+
   /* Check if somebody tries to add ourself */
 
   if(!strcmp(name, myself->name))
     {
-      syslog(LOG_ERR, _("Warning: got ADD_HOST from %s (%s) for ourself, restarting"), cl->name, cl->hostname);
-      sighup = 1;
+      syslog(LOG_ERR, _("Got ADD_HOST from %s (%s) for ourself!"), cl->name, cl->hostname);
       free_connection(new);
-      return 0;
+      return -1;
     }
     
   /* Fill in more of the new connection structure */
 
   new->hostname = hostlookup(htonl(new->address));
 
+  new->lastbutonehop = lookup_id(lastbutone);
+  
+  if(!new->lastbutonehop)
+    {
+      syslog(LOG_ERR, _("Got bad ADD_HOST from %s (%s): unknown lastbutone"), cl->name, cl->hostname);
+      free_connection(new);
+      return -1;
+    }
+
   /* Check if the new host already exists in the connnection list */
 
   if((old = lookup_id(name)))
     {
-      if((new->address == old->address) && (new->port == old->port))
+      if((new->address == old->address) && (new->port == old->port) && (cl->nexthop == old->nexthop))
         {
           if(debug_lvl >= DEBUG_CONNECTIONS)
             syslog(LOG_NOTICE, _("Got duplicate ADD_HOST for %s (%s) from %s (%s)"),
-                   old->name, old->hostname, name, new->hostname);
+                   old->name, old->hostname, cl->name, cl->hostname);
           free_connection(new);
           return 0;
         }
       else
         {
           if(debug_lvl >= DEBUG_CONNECTIONS)
-            syslog(LOG_NOTICE, _("Removing old entry for %s (%s) in favour of new connection"),
-                   old->name, old->hostname);
+            syslog(LOG_NOTICE, _("Removing old entry for %s (%s) from %s in favour of new connection from %s"),
+                   old->name, old->hostname, old->nexthop->name, cl->nexthop->name);
 
-          terminate_connection(old);
+          terminate_connection(old, 0);
         }
     }
 
-  /* Hook it up into the connection */
+  /* Hook it up into the active tree */
 
   new->name = xstrdup(name);
-  connection_add(new);
-  id_add(new);
+  active_add(new);
 
   /* Tell the rest about the new host */
 
   for(node = connection_tree->head; node; node = node->next)
     {
       p = (connection_t *)node->data;
-      if(p->status.meta && p->status.active && p!=cl)
+      if(p->status.active && p!=cl)
         send_add_host(p, new);
     }
 
   /* Fill in rest of connection structure */
 
   new->nexthop = cl;
-  new->status.active = 1;
-  new->cipher_pkttype = EVP_bf_cfb();
+  new->cipher_pkttype = EVP_bf_cbc();
   new->cipher_pktkeylength = cl->cipher_pkttype->key_len + cl->cipher_pkttype->iv_len;
 cp
   return 0;
@@ -937,21 +880,20 @@ cp
 int send_del_host(connection_t *cl, connection_t *other)
 {
 cp
-  if(!(cl->options & OPTION_INDIRECT))
-    return send_request(cl, "%d %s %lx:%d %lx", DEL_HOST,
-                      other->name, other->address, other->port, other->options);
+  return send_request(cl, "%d %s %lx:%d %lx %s", DEL_HOST,
+                      other->name, other->address, other->port, other->options, other->lastbutonehop->name);
 }
 
 int del_host_h(connection_t *cl)
 {
-  char name[MAX_STRING_SIZE];
-  ip_t address;
+  char name[MAX_STRING_SIZE], lastbutone[MAX_STRING_SIZE];
+  ipv4_t address;
   port_t port;
   long int options;
   connection_t *old, *p;
   avl_node_t *node;
 cp
-  if(sscanf(cl->buffer, "%*d "MAX_STRING" %lx:%d %lx", name, &address, &port, &options) != 4)
+  if(sscanf(cl->buffer, "%*d "MAX_STRING" %lx:%hd %lx "MAX_STRING, name, &address, &port, &options, lastbutone) != 5)
     {
       syslog(LOG_ERR, _("Got bad DEL_HOST from %s (%s)"),
              cl->name, cl->hostname);
@@ -966,28 +908,33 @@ cp
       return -1;
     }
 
+  if(check_id(lastbutone))
+    {
+      syslog(LOG_ERR, _("Got bad DEL_HOST from %s (%s): invalid lastbutone name"), cl->name, cl->hostname);
+      return -1;
+    }
+
   /* Check if somebody tries to delete ourself */
 
   if(!strcmp(name, myself->name))
     {
-      syslog(LOG_ERR, _("Warning: got DEL_HOST from %s (%s) for ourself, restarting"),
+      syslog(LOG_ERR, _("Got DEL_HOST from %s (%s) for ourself!"),
              cl->name, cl->hostname);
-      sighup = 1;
-      return 0;
+      return -1;
     }
 
-  /* Check if the new host already exists in the connnection list */
+  /* Check if the deleted host already exists in the connnection list */
 
   if(!(old = lookup_id(name)))
     {
       syslog(LOG_ERR, _("Got DEL_HOST from %s (%s) for %s which is not in our connection list"),
-             name, cl->name, cl->hostname);
+             cl->name, cl->hostname, name);
       return -1;
     }
   
   /* Check if the rest matches */
   
-  if(address!=old->address || port!=old->port || options!=old->options || cl!=old->nexthop)
+  if(address!=old->address || port!=old->port || options!=old->options || cl!=old->nexthop || strcmp(lastbutone, old->lastbutonehop->name))
     {
       syslog(LOG_WARNING, _("Got DEL_HOST from %s (%s) for %s which doesn't match"), cl->name, cl->hostname, old->name);
       return 0;
@@ -995,15 +942,14 @@ cp
 
   /* Ok, since EVERYTHING seems to check out all right, delete it */
 
-  old->status.active = 0;
-  terminate_connection(old);
+  terminate_connection(old, 0);
 
-  /* Tell the rest about the new host */
+  /* Tell the rest about the deleted host */
 
   for(node = connection_tree->head; node; node = node->next)
     {
       p = (connection_t *)node->data;
-      if(p->status.meta && p->status.active && p!=cl)
+      if(p->status.active && p!=cl)
         send_del_host(p, old);
     }
 cp
@@ -1043,20 +989,20 @@ cp
   return 0;
 }
 
-int send_error(connection_t *cl, int errno, char *errstring)
+int send_error(connection_t *cl, int err, char *errstring)
 {
 cp
   if(!errstring)
-    errstring = strerror(errno);
-  return send_request(cl, "%d %d %s", ERROR, errno, errstring);
+    errstring = strerror(err);
+  return send_request(cl, "%d %d %s", ERROR, err, errstring);
 }
 
 int error_h(connection_t *cl)
 {
-  int errno;
+  int err;
   char errorstring[MAX_STRING_SIZE];
 cp
-  if(sscanf(cl->buffer, "%*d %d "MAX_STRING, &errno, errorstring) != 2)
+  if(sscanf(cl->buffer, "%*d %d "MAX_STRING, &err, errorstring) != 2)
     {
        syslog(LOG_ERR, _("Got bad ERROR from %s (%s)"),
               cl->name, cl->hostname);
@@ -1066,10 +1012,10 @@ cp
   if(debug_lvl >= DEBUG_ERROR)
     {
       syslog(LOG_NOTICE, _("Error message from %s (%s): %s: %s"),
-             cl->name, cl->hostname, strerror(errno), errorstring);
+             cl->name, cl->hostname, strerror(err), errorstring);
     }
 
-  terminate_connection(cl);
+  terminate_connection(cl, cl->status.meta);
 cp
   return 0;
 }
@@ -1083,18 +1029,22 @@ cp
 int termreq_h(connection_t *cl)
 {
 cp
-  terminate_connection(cl);
+  terminate_connection(cl, cl->status.meta);
 cp
   return 0;
 }
 
 int send_ping(connection_t *cl)
 {
+  char salt[SALTLEN*2+1];
 cp
   cl->status.pinged = 1;
   cl->last_ping_time = time(NULL);
+  RAND_pseudo_bytes(salt, SALTLEN);
+  bin2hex(salt, salt, SALTLEN);
+  salt[SALTLEN*2] = '\0';
 cp
-  return send_request(cl, "%d", PING);
+  return send_request(cl, "%d %s", PING, salt);
 }
 
 int ping_h(connection_t *cl)
@@ -1105,8 +1055,13 @@ cp
 
 int send_pong(connection_t *cl)
 {
+  char salt[SALTLEN*2+1];
 cp
-  return send_request(cl, "%d", PONG);
+  RAND_pseudo_bytes(salt, SALTLEN);
+  bin2hex(salt, salt, SALTLEN);
+  salt[SALTLEN*2] = '\0';
+cp
+  return send_request(cl, "%d %s", PONG, salt);
 }
 
 int pong_h(connection_t *cl)
@@ -1124,12 +1079,18 @@ int send_key_changed(connection_t *from, connection_t *cl)
   connection_t *p;
   avl_node_t *node;
 cp
+  /* Only send this message if some other daemon requested our key previously.
+     This reduces unnecessary key_changed broadcasts.
+  */
+
+  if(from==myself && !mykeyused)
+    return 0;
+
   for(node = connection_tree->head; node; node = node->next)
     {
       p = (connection_t *)node->data;
-      if(p != cl && p->status.meta && p->status.active)
-        if(!(cl->options & OPTION_INDIRECT) || from == myself)
-          send_request(p, "%d %s", KEY_CHANGED, from->name);
+      if(p != cl && p->status.active)
+        send_request(p, "%d %s", KEY_CHANGED, from->name);
     }
 cp
   return 0;
@@ -1192,11 +1153,12 @@ cp
 
   /* Check if this key request is for us */
 
-  if(!strcmp(to_id, myself->name))
+  if(!strcmp(to_id, myself->name))	/* Yes, send our own key back */
     {
       bin2hex(myself->cipher_pktkey, pktkey, myself->cipher_pktkeylength);
       pktkey[myself->cipher_pktkeylength*2] = '\0';
       send_ans_key(myself, from, pktkey);
+      mykeyused = 1;
     }
   else
     {
@@ -1295,52 +1257,38 @@ cp
 int send_tcppacket(connection_t *cl, vpn_packet_t *packet)
 {
   int x;
-  
+cp  
+  /* Evil hack. */
+
   x = send_request(cl->nexthop, "%d %hd", PACKET, packet->len);
 
   if(x)
     return x;
-  
-  return send_meta(cl->nexthop, packet->data, packet->len);  
+cp
+  return send_meta(cl, packet->data, packet->len);
 }
 
 int tcppacket_h(connection_t *cl)
 {
-  vpn_packet_t packet;
-  char *p;
-  int todo, x;
-  
-  if(sscanf(cl->buffer, "%*d %hd", packet.len) != 1)
+  short int len;
+cp  
+  if(sscanf(cl->buffer, "%*d %hd", &len) != 1)
     {
       syslog(LOG_ERR, _("Got bad PACKET from %s (%s)"), cl->name, cl->hostname);
       return -1;
     }
 
-  /* Evil hack. */
+  /* Set reqlen to len, this will tell receive_meta() that a tcppacket is coming. */
 
-  p = packet.data;
-  todo = packet.len;
-  
-  while(todo)
-    {
-      x = read(cl->meta_socket, p, todo);
-      if(x<0)
-        {
-          syslog(LOG_ERR, _("Error during reception of PACKET from %s (%s): %m"), cl->name, cl->hostname);
-          return -1;
-        }
-      
-      todo -= x;
-      p += x;
-    }
-
-  return receive_packet(cl, &packet);
+  cl->tcplen = len;
+cp
+  return 0;
 }
 
 /* Jumptable for the request handlers */
 
 int (*request_handlers[])(connection_t*) = {
-  id_h, challenge_h, chal_reply_h, metakey_h, ack_h,
+  id_h, metakey_h, challenge_h, chal_reply_h,
   status_h, error_h, termreq_h,
   ping_h, pong_h,
   add_host_h, del_host_h,
@@ -1352,7 +1300,7 @@ int (*request_handlers[])(connection_t*) = {
 /* Request names */
 
 char (*request_name[]) = {
-  "ID", "CHALLENGE", "CHAL_REPLY", "METAKEY", "ACK",
+  "ID", "METAKEY", "CHALLENGE", "CHAL_REPLY",
   "STATUS", "ERROR", "TERMREQ",
   "PING", "PONG",
   "ADD_HOST", "DEL_HOST",