Fixed failure handling.
[silc.git] / lib / silcske / silcske.c
index c0e8d7f153392b7a95b077defe7e538cbba654c3..c222e49b6a3b13b5dd1fab4fb2af2e5c772fd5c1 100644 (file)
@@ -4,7 +4,7 @@
 
   Author: Pekka Riikonen <priikone@silcnet.org>
 
-  Copyright (C) 2000 - 2005 Pekka Riikonen
+  Copyright (C) 2000 - 2006 Pekka Riikonen
 
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -31,22 +31,37 @@ struct SilcSKECallbacksStruct {
   void *context;
 };
 
-
 /************************ Static utility functions **************************/
 
-SilcSKEKeyMaterial
-silc_ske_process_key_material_data(unsigned char *data,
-                                  SilcUInt32 data_len,
-                                  SilcUInt32 req_iv_len,
-                                  SilcUInt32 req_enc_key_len,
-                                  SilcUInt32 req_hmac_key_len,
-                                  SilcHash hash);
+SILC_FSM_STATE(silc_ske_st_initiator_start);
+SILC_FSM_STATE(silc_ske_st_initiator_phase1);
+SILC_FSM_STATE(silc_ske_st_initiator_phase2);
+SILC_FSM_STATE(silc_ske_st_initiator_phase3);
+SILC_FSM_STATE(silc_ske_st_initiator_phase4);
+SILC_FSM_STATE(silc_ske_st_initiator_end);
+SILC_FSM_STATE(silc_ske_st_initiator_aborted);
+SILC_FSM_STATE(silc_ske_st_initiator_error);
+SILC_FSM_STATE(silc_ske_st_initiator_failure);
+SILC_FSM_STATE(silc_ske_st_responder_start);
+SILC_FSM_STATE(silc_ske_st_responder_phase1);
+SILC_FSM_STATE(silc_ske_st_responder_phase2);
+SILC_FSM_STATE(silc_ske_st_responder_phase4);
+SILC_FSM_STATE(silc_ske_st_responder_phase5);
+SILC_FSM_STATE(silc_ske_st_responder_end);
+SILC_FSM_STATE(silc_ske_st_responder_aborted);
+SILC_FSM_STATE(silc_ske_st_responder_failure);
+SILC_FSM_STATE(silc_ske_st_responder_error);
+
 SilcSKEKeyMaterial
 silc_ske_process_key_material(SilcSKE ske,
                              SilcUInt32 req_iv_len,
                              SilcUInt32 req_enc_key_len,
                              SilcUInt32 req_hmac_key_len);
-
+static SilcBool silc_ske_packet_send(SilcSKE ske,
+                                    SilcPacketType type,
+                                    SilcPacketFlags flags,
+                                    const unsigned char *data,
+                                    SilcUInt32 data_len);
 
 /* Packet callback */
 
@@ -85,17 +100,48 @@ static void silc_ske_pk_verified(SilcSKE ske, SilcSKEStatus status,
   SILC_FSM_CALL_CONTINUE(&ske->fsm);
 }
 
+/* SKR find callback */
+
+static void silc_ske_skr_callback(SilcSKR repository,
+                                 SilcSKRFind find,
+                                 SilcSKRStatus status,
+                                 SilcDList keys, void *context)
+{
+  SilcSKE ske = context;
+
+  silc_skr_find_free(find);
+
+  if (status != SILC_SKR_OK) {
+    if (ske->callbacks->verify_key) {
+      /* Verify from application */
+      ske->callbacks->verify_key(ske, ske->prop->public_key,
+                                ske->callbacks->context,
+                                silc_ske_pk_verified, NULL);
+      return;
+    }
+  }
+
+  if (keys)
+    silc_dlist_uninit(keys);
+
+  /* Continue */
+  ske->status = (status == SILC_SKR_OK ? SILC_SKE_STATUS_OK :
+                SILC_SKE_STATUS_UNSUPPORTED_PUBLIC_KEY);
+  SILC_FSM_CALL_CONTINUE(&ske->fsm);
+}
+
 /* Checks remote and local versions */
 
 static SilcSKEStatus silc_ske_check_version(SilcSKE ske)
 {
   SilcUInt32 l_protocol_version = 0, r_protocol_version = 0;
+  SilcUInt32 r_software_version = 0;
 
   if (!ske->remote_version || !ske->version)
     return SILC_SKE_STATUS_BAD_VERSION;
 
   if (!silc_parse_version_string(ske->remote_version, &r_protocol_version,
-                                NULL, NULL, NULL, NULL))
+                                NULL, &r_software_version, NULL, NULL))
     return SILC_SKE_STATUS_BAD_VERSION;
 
   if (!silc_parse_version_string(ske->version, &l_protocol_version,
@@ -106,19 +152,32 @@ static SilcSKEStatus silc_ske_check_version(SilcSKE ske)
   if (l_protocol_version < r_protocol_version)
     return SILC_SKE_STATUS_BAD_VERSION;
 
+  /* Backwards compatibility checks */
+
+  /* Old server versions requires "valid" looking Source ID in the SILC
+     packets during initial key exchange.  All version before 1.1.0. */
+  if (r_software_version < 110) {
+    SilcClientID id;
+    memset(&id, 0, sizeof(id));
+    id.ip.data_len = 4;
+    SILC_LOG_DEBUG(("Remote is old version, add dummy Source ID to packets"));
+    silc_packet_set_ids(ske->stream, SILC_ID_CLIENT, &id, 0, NULL);
+  }
+
   return SILC_SKE_STATUS_OK;
 }
 
 /* Selects the supported security properties from the initiator's Key
-   Exchange Start Payload. */
+   Exchange Start Payload.  A responder function.  Saves our reply
+   start payload to ske->start_payload. */
 
 static SilcSKEStatus
 silc_ske_select_security_properties(SilcSKE ske,
-                                   SilcSKEStartPayload payload,
-                                   SilcSKEStartPayload remote_payload)
+                                   SilcSKEStartPayload remote_payload,
+                                   SilcSKESecurityProperties *prop)
 {
   SilcSKEStatus status;
-  SilcSKEStartPayload rp;
+  SilcSKEStartPayload rp, payload;
   char *cp;
   int len;
 
@@ -126,6 +185,40 @@ silc_ske_select_security_properties(SilcSKE ske,
 
   rp = remote_payload;
 
+  /* Check for mandatory fields */
+  if (!rp->ke_grp_len) {
+    SILC_LOG_DEBUG(("KE group not defined in payload"));
+    return SILC_SKE_STATUS_BAD_PAYLOAD;
+  }
+  if (!rp->pkcs_alg_len) {
+    SILC_LOG_DEBUG(("PKCS alg not defined in payload"));
+    return SILC_SKE_STATUS_BAD_PAYLOAD;
+  }
+  if (!rp->enc_alg_len) {
+    SILC_LOG_DEBUG(("Encryption alg not defined in payload"));
+    return SILC_SKE_STATUS_BAD_PAYLOAD;
+  }
+  if (!rp->hash_alg_len) {
+    SILC_LOG_DEBUG(("Hash alg not defined in payload"));
+    return SILC_SKE_STATUS_BAD_PAYLOAD;
+  }
+  if (!rp->hmac_alg_len) {
+    SILC_LOG_DEBUG(("HMAC not defined in payload"));
+    return SILC_SKE_STATUS_BAD_PAYLOAD;
+  }
+
+  /* Allocate security properties */
+  *prop = silc_calloc(1, sizeof(**prop));
+  if (!(*prop))
+    return SILC_SKE_STATUS_OUT_OF_MEMORY;
+
+  /* Allocate our reply start payload */
+  payload = silc_calloc(1, sizeof(*payload));
+  if (!payload) {
+    silc_free(*prop);
+    return SILC_SKE_STATUS_OUT_OF_MEMORY;
+  }
+
   /* Check version string */
   ske->remote_version = silc_memdup(rp->version, rp->version_len);
   status = silc_ske_check_version(ske);
@@ -135,7 +228,7 @@ silc_ske_select_security_properties(SilcSKE ske,
   }
 
   /* Flags are returned unchanged. */
-  payload->flags = rp->flags;
+  (*prop)->flags = payload->flags = rp->flags;
 
   /* Take cookie, we must return it to sender unmodified. */
   payload->cookie = silc_calloc(SILC_SKE_COOKIE_LEN, sizeof(unsigned char));
@@ -146,6 +239,16 @@ silc_ske_select_security_properties(SilcSKE ske,
   payload->cookie_len = SILC_SKE_COOKIE_LEN;
   memcpy(payload->cookie, rp->cookie, SILC_SKE_COOKIE_LEN);
 
+  /* In case IV included flag and session port is set the first 16-bits of
+     cookie will include our session port. */
+  if (rp->flags & SILC_SKE_SP_FLAG_IV_INCLUDED && ske->session_port) {
+    /* Take remote port */
+    SILC_GET16_MSB((*prop)->remote_port, payload->cookie);
+
+    /* Put out port */
+    SILC_PUT16_MSB(ske->session_port, payload->cookie);
+  }
+
   /* Put our version to our reply */
   payload->version = strdup(ske->version);
   if (!payload->version) {
@@ -194,13 +297,6 @@ silc_ske_select_security_properties(SilcSKE ske,
       return SILC_SKE_STATUS_UNKNOWN_GROUP;
     }
   } else {
-
-    if (!rp->ke_grp_len) {
-      SILC_LOG_DEBUG(("KE group not defined in payload"));
-      silc_free(payload);
-      return SILC_SKE_STATUS_BAD_PAYLOAD;
-    }
-
     SILC_LOG_DEBUG(("Proposed KE group `%s'", rp->ke_grp_list));
     SILC_LOG_DEBUG(("Found KE group `%s'", rp->ke_grp_list));
 
@@ -208,6 +304,13 @@ silc_ske_select_security_properties(SilcSKE ske,
     payload->ke_grp_list = strdup(rp->ke_grp_list);
   }
 
+  /* Save group to security properties */
+  status = silc_ske_group_get_by_name(payload->ke_grp_list, &(*prop)->group);
+  if (status != SILC_SKE_STATUS_OK) {
+    silc_free(payload);
+    return SILC_SKE_STATUS_UNKNOWN_GROUP;
+  }
+
   /* Get supported PKCS algorithms */
   cp = rp->pkcs_alg_list;
   if (cp && strchr(cp, ',')) {
@@ -249,14 +352,6 @@ silc_ske_select_security_properties(SilcSKE ske,
       return SILC_SKE_STATUS_UNKNOWN_PKCS;
     }
   } else {
-
-    if (!rp->pkcs_alg_len) {
-      SILC_LOG_DEBUG(("PKCS alg not defined in payload"));
-      silc_free(payload->ke_grp_list);
-      silc_free(payload);
-      return SILC_SKE_STATUS_BAD_PAYLOAD;
-    }
-
     SILC_LOG_DEBUG(("Proposed PKCS alg `%s'", rp->pkcs_alg_list));
     SILC_LOG_DEBUG(("Found PKCS alg `%s'", rp->pkcs_alg_list));
 
@@ -306,15 +401,6 @@ silc_ske_select_security_properties(SilcSKE ske,
       return SILC_SKE_STATUS_UNKNOWN_CIPHER;
     }
   } else {
-
-    if (!rp->enc_alg_len) {
-      SILC_LOG_DEBUG(("Encryption alg not defined in payload"));
-      silc_free(payload->ke_grp_list);
-      silc_free(payload->pkcs_alg_list);
-      silc_free(payload);
-      return SILC_SKE_STATUS_BAD_PAYLOAD;
-    }
-
     SILC_LOG_DEBUG(("Proposed encryption alg `%s' and selected it",
                    rp->enc_alg_list));
 
@@ -322,6 +408,14 @@ silc_ske_select_security_properties(SilcSKE ske,
     payload->enc_alg_list = strdup(rp->enc_alg_list);
   }
 
+  /* Save selected cipher to security properties */
+  if (silc_cipher_alloc(payload->enc_alg_list, &(*prop)->cipher) == FALSE) {
+    silc_free(payload->ke_grp_list);
+    silc_free(payload->pkcs_alg_list);
+    silc_free(payload);
+    return SILC_SKE_STATUS_UNKNOWN_CIPHER;
+  }
+
   /* Get supported hash algorithms */
   cp = rp->hash_alg_list;
   if (cp && strchr(cp, ',')) {
@@ -365,16 +459,6 @@ silc_ske_select_security_properties(SilcSKE ske,
       return SILC_SKE_STATUS_UNKNOWN_HASH_FUNCTION;
     }
   } else {
-
-    if (!rp->hash_alg_len) {
-      SILC_LOG_DEBUG(("Hash alg not defined in payload"));
-      silc_free(payload->ke_grp_list);
-      silc_free(payload->pkcs_alg_list);
-      silc_free(payload->enc_alg_list);
-      silc_free(payload);
-      return SILC_SKE_STATUS_BAD_PAYLOAD;
-    }
-
     SILC_LOG_DEBUG(("Proposed hash alg `%s' and selected it",
                    rp->hash_alg_list));
 
@@ -382,6 +466,15 @@ silc_ske_select_security_properties(SilcSKE ske,
     payload->hash_alg_list = strdup(rp->hash_alg_list);
   }
 
+  /* Save selected hash algorithm to security properties */
+  if (silc_hash_alloc(payload->hash_alg_list, &(*prop)->hash) == FALSE) {
+    silc_free(payload->ke_grp_list);
+    silc_free(payload->pkcs_alg_list);
+    silc_free(payload->enc_alg_list);
+    silc_free(payload);
+    return SILC_SKE_STATUS_UNKNOWN_HASH_FUNCTION;
+  }
+
   /* Get supported HMACs */
   cp = rp->hmac_alg_list;
   if (cp && strchr(cp, ',')) {
@@ -426,17 +519,6 @@ silc_ske_select_security_properties(SilcSKE ske,
       return SILC_SKE_STATUS_UNKNOWN_HMAC;
     }
   } else {
-
-    if (!rp->hmac_alg_len) {
-      SILC_LOG_DEBUG(("HMAC not defined in payload"));
-      silc_free(payload->ke_grp_list);
-      silc_free(payload->pkcs_alg_list);
-      silc_free(payload->enc_alg_list);
-      silc_free(payload->hash_alg_list);
-      silc_free(payload);
-      return SILC_SKE_STATUS_BAD_PAYLOAD;
-    }
-
     SILC_LOG_DEBUG(("Proposed HMAC `%s' and selected it",
                    rp->hmac_alg_list));
 
@@ -444,6 +526,16 @@ silc_ske_select_security_properties(SilcSKE ske,
     payload->hmac_alg_list = strdup(rp->hmac_alg_list);
   }
 
+  /* Save selected HMACc to security properties */
+  if (silc_hmac_alloc(payload->hmac_alg_list, NULL, &(*prop)->hmac) == FALSE) {
+    silc_free(payload->ke_grp_list);
+    silc_free(payload->pkcs_alg_list);
+    silc_free(payload->enc_alg_list);
+    silc_free(payload->hash_alg_list);
+    silc_free(payload);
+    return SILC_SKE_STATUS_UNKNOWN_HMAC;
+  }
+
   /* Get supported compression algorithms */
   cp = rp->comp_alg_list;
   if (cp && strchr(cp, ',')) {
@@ -493,6 +585,9 @@ silc_ske_select_security_properties(SilcSKE ske,
     2 + payload->enc_alg_len + 2 + payload->hash_alg_len +
     2 + payload->hmac_alg_len + 2 + payload->comp_alg_len;
 
+  /* Save our reply payload */
+  ske->start_payload = payload;
+
   return SILC_SKE_STATUS_OK;
 }
 
@@ -657,14 +752,140 @@ static SilcSKEStatus silc_ske_make_hash(SilcSKE ske,
   return status;
 }
 
+/* Assembles security properties */
+
+static SilcSKEStartPayload
+silc_ske_assemble_security_properties(SilcSKE ske,
+                                     SilcSKESecurityPropertyFlag flags,
+                                     const char *version)
+{
+  SilcSKEStartPayload rp;
+  int i;
+
+  SILC_LOG_DEBUG(("Assembling KE Start Payload"));
+
+  rp = silc_calloc(1, sizeof(*rp));
+
+  /* Set flags */
+  rp->flags = (unsigned char)flags;
+
+  /* Set random cookie */
+  rp->cookie = silc_calloc(SILC_SKE_COOKIE_LEN, sizeof(*rp->cookie));
+  for (i = 0; i < SILC_SKE_COOKIE_LEN; i++)
+    rp->cookie[i] = silc_rng_get_byte_fast(ske->rng);
+  rp->cookie_len = SILC_SKE_COOKIE_LEN;
+
+  /* In case IV included flag and session port is set the first 16-bits of
+     cookie will include our session port. */
+  if (flags & SILC_SKE_SP_FLAG_IV_INCLUDED && ske->session_port)
+    SILC_PUT16_MSB(ske->session_port, rp->cookie);
+
+  /* Put version */
+  rp->version = strdup(version);
+  rp->version_len = strlen(version);
+
+  /* Get supported Key Exhange groups */
+  rp->ke_grp_list = silc_ske_get_supported_groups();
+  rp->ke_grp_len = strlen(rp->ke_grp_list);
+
+  /* Get supported PKCS algorithms */
+  rp->pkcs_alg_list = silc_pkcs_get_supported();
+  rp->pkcs_alg_len = strlen(rp->pkcs_alg_list);
+
+  /* Get supported encryption algorithms */
+  rp->enc_alg_list = silc_cipher_get_supported();
+  rp->enc_alg_len = strlen(rp->enc_alg_list);
+
+  /* Get supported hash algorithms */
+  rp->hash_alg_list = silc_hash_get_supported();
+  rp->hash_alg_len = strlen(rp->hash_alg_list);
+
+  /* Get supported HMACs */
+  rp->hmac_alg_list = silc_hmac_get_supported();
+  rp->hmac_alg_len = strlen(rp->hmac_alg_list);
+
+  /* XXX */
+  /* Get supported compression algorithms */
+  rp->comp_alg_list = strdup("none");
+  rp->comp_alg_len = strlen("none");
+
+  rp->len = 1 + 1 + 2 + SILC_SKE_COOKIE_LEN +
+    2 + rp->version_len +
+    2 + rp->ke_grp_len + 2 + rp->pkcs_alg_len +
+    2 + rp->enc_alg_len + 2 + rp->hash_alg_len +
+    2 + rp->hmac_alg_len + 2 + rp->comp_alg_len;
+
+  return rp;
+}
+
+/* Packet retransmission callback. */
+
+SILC_TASK_CALLBACK(silc_ske_packet_send_retry)
+{
+  SilcSKE ske = context;
+
+  if (ske->retry_count++ >= SILC_SKE_RETRY_COUNT ||
+      ske->aborted) {
+    SILC_LOG_DEBUG(("Retry limit reached, packet was lost"));
+    ske->retry_count = 0;
+    ske->retry_timer = SILC_SKE_RETRY_MIN;
+    silc_free(ske->retrans.data);
+    ske->retrans.data = NULL;
+    ske->status = SILC_SKE_STATUS_TIMEOUT;
+    if (ske->responder)
+      silc_fsm_next(&ske->fsm, silc_ske_st_responder_failure);
+    else
+      silc_fsm_next(&ske->fsm, silc_ske_st_initiator_failure);
+    silc_fsm_continue_sync(&ske->fsm);
+    return;
+  }
+
+  SILC_LOG_DEBUG(("Retransmitting packet"));
+  silc_ske_packet_send(ske, ske->retrans.type, ske->retrans.flags,
+                      ske->retrans.data, ske->retrans.data_len);
+}
+
+/* Sends SILC packet.  Handles retransmissions with UDP streams. */
+
+static SilcBool silc_ske_packet_send(SilcSKE ske,
+                                    SilcPacketType type,
+                                    SilcPacketFlags flags,
+                                    const unsigned char *data,
+                                    SilcUInt32 data_len)
+{
+  SilcBool ret;
+
+  /* Send the packet */
+  ret = silc_packet_send(ske->stream, type, flags, data, data_len);
+
+  if (silc_packet_stream_is_udp(ske->stream) &&
+      type != SILC_PACKET_FAILURE) {
+    silc_free(ske->retrans.data);
+    ske->retrans.type = type;
+    ske->retrans.flags = flags;
+    ske->retrans.data = silc_memdup(data, data_len);
+    ske->retrans.data_len = data_len;
+    if (ske->retrans.data) {
+      SILC_LOG_DEBUG(("Installing retransmission timer %d secs",
+                     ske->retry_timer));
+      silc_schedule_task_add_timeout(ske->schedule, silc_ske_packet_send_retry,
+                                    ske, ske->retry_timer, 0);
+    }
+    ske->retry_timer = ((ske->retry_timer * SILC_SKE_RETRY_MUL) +
+                       (silc_rng_get_rn16(ske->rng) % SILC_SKE_RETRY_RAND));
+  }
+
+  return ret;
+}
+
 
 /******************************* Protocol API *******************************/
 
 /* Allocates new SKE object. */
 
 SilcSKE silc_ske_alloc(SilcRng rng, SilcSchedule schedule,
-                      SilcPublicKey public_key, SilcPrivateKey private_key,
-                      void *context)
+                      SilcSKR repository, SilcPublicKey public_key,
+                      SilcPrivateKey private_key, void *context)
 {
   SilcSKE ske;
 
@@ -673,16 +894,22 @@ SilcSKE silc_ske_alloc(SilcRng rng, SilcSchedule schedule,
   if (!rng || !schedule)
     return NULL;
 
+  if (!public_key) {
+    SILC_LOG_ERROR(("Public key must be given to silc_ske_alloc"));
+    return NULL;
+  }
+
   ske = silc_calloc(1, sizeof(*ske));
   if (!ske)
     return NULL;
   ske->status = SILC_SKE_STATUS_OK;
   ske->rng = rng;
+  ske->repository = repository;
   ske->user_data = context;
   ske->schedule = schedule;
   ske->public_key = public_key;
   ske->private_key = private_key;
-  ske->pk_type = SILC_SKE_PK_TYPE_SILC;
+  ske->retry_timer = SILC_SKE_RETRY_MIN;
 
   return ske;
 }
@@ -693,46 +920,53 @@ void silc_ske_free(SilcSKE ske)
 {
   SILC_LOG_DEBUG(("Freeing Key Exchange object"));
 
-  if (ske) {
-    /* Free start payload */
-    if (ske->start_payload)
-      silc_ske_payload_start_free(ske->start_payload);
-
-    /* Free KE payload */
-    if (ske->ke1_payload)
-      silc_ske_payload_ke_free(ske->ke1_payload);
-    if (ske->ke2_payload)
-      silc_ske_payload_ke_free(ske->ke2_payload);
-    silc_free(ske->remote_version);
-
-    /* Free rest */
-    if (ske->prop) {
-      if (ske->prop->group)
-       silc_ske_group_free(ske->prop->group);
-      if (ske->prop->cipher)
-       silc_cipher_free(ske->prop->cipher);
-      if (ske->prop->hash)
-       silc_hash_free(ske->prop->hash);
-      if (ske->prop->hmac)
-       silc_hmac_free(ske->prop->hmac);
-      silc_free(ske->prop);
-    }
-    if (ske->start_payload_copy)
-      silc_buffer_free(ske->start_payload_copy);
-    if (ske->x) {
-      silc_mp_uninit(ske->x);
-      silc_free(ske->x);
-    }
-    if (ske->KEY) {
-      silc_mp_uninit(ske->KEY);
-      silc_free(ske->KEY);
-    }
-    silc_free(ske->hash);
-    silc_free(ske->callbacks);
+  if (!ske)
+    return;
 
-    memset(ske, 'F', sizeof(*ske));
-    silc_free(ske);
+  if (ske->running) {
+    ske->freed = TRUE;
+    return;
+  }
+
+  /* Free start payload */
+  if (ske->start_payload)
+    silc_ske_payload_start_free(ske->start_payload);
+
+  /* Free KE payload */
+  if (ske->ke1_payload)
+    silc_ske_payload_ke_free(ske->ke1_payload);
+  if (ske->ke2_payload)
+    silc_ske_payload_ke_free(ske->ke2_payload);
+  silc_free(ske->remote_version);
+
+  /* Free rest */
+  if (ske->prop) {
+    if (ske->prop->group)
+      silc_ske_group_free(ske->prop->group);
+    if (ske->prop->cipher)
+      silc_cipher_free(ske->prop->cipher);
+    if (ske->prop->hash)
+      silc_hash_free(ske->prop->hash);
+    if (ske->prop->hmac)
+      silc_hmac_free(ske->prop->hmac);
+      silc_free(ske->prop);
   }
+  if (ske->start_payload_copy)
+    silc_buffer_free(ske->start_payload_copy);
+  if (ske->x) {
+    silc_mp_uninit(ske->x);
+    silc_free(ske->x);
+  }
+  if (ske->KEY) {
+    silc_mp_uninit(ske->KEY);
+    silc_free(ske->KEY);
+  }
+  silc_free(ske->retrans.data);
+  silc_free(ske->hash);
+  silc_free(ske->callbacks);
+
+  memset(ske, 'F', sizeof(*ske));
+  silc_free(ske);
 }
 
 /* Return user context */
@@ -762,16 +996,6 @@ void silc_ske_set_callbacks(SilcSKE ske,
 
 /******************************** Initiator *********************************/
 
-/* Initiator state machine */
-SILC_FSM_STATE(silc_ske_st_initiator_start);
-SILC_FSM_STATE(silc_ske_st_initiator_phase1);
-SILC_FSM_STATE(silc_ske_st_initiator_phase2);
-SILC_FSM_STATE(silc_ske_st_initiator_phase3);
-SILC_FSM_STATE(silc_ske_st_initiator_phase4);
-SILC_FSM_STATE(silc_ske_st_initiator_end);
-SILC_FSM_STATE(silc_ske_st_initiator_aborted);
-SILC_FSM_STATE(silc_ske_st_initiator_error);
-
 /* Start protocol.  Send our proposal */
 
 SILC_FSM_STATE(silc_ske_st_initiator_start)
@@ -802,12 +1026,22 @@ SILC_FSM_STATE(silc_ske_st_initiator_start)
      compute the HASH value. */
   ske->start_payload_copy = payload_buf;
 
-  /* Send the packet */
-  /* XXX */
+  /* Send the packet. */
+  if (!silc_ske_packet_send(ske, SILC_PACKET_KEY_EXCHANGE, 0,
+                           silc_buffer_data(payload_buf),
+                           silc_buffer_len(payload_buf))) {
+    /** Error sending packet */
+    SILC_LOG_DEBUG(("Error sending packet"));
+    ske->status = SILC_SKE_STATUS_ERROR;
+    silc_fsm_next(fsm, silc_ske_st_initiator_error);
+    return SILC_FSM_CONTINUE;
+  }
+
+  /* XXX timeout */
 
   /** Wait for responder proposal */
   SILC_LOG_DEBUG(("Waiting for reponder proposal"));
-  silc_fsm_next(ske, silc_ske_st_initiator_phase1);
+  silc_fsm_next(fsm, silc_ske_st_initiator_phase1);
   return SILC_FSM_WAIT;
 }
 
@@ -819,31 +1053,77 @@ SILC_FSM_STATE(silc_ske_st_initiator_phase1)
   SilcSKEStatus status;
   SilcSKEStartPayload payload;
   SilcSKESecurityProperties prop;
-  SilcSKEDiffieHellmanGroup group;
+  SilcSKEDiffieHellmanGroup group = NULL;
   SilcBuffer packet_buf = &ske->packet->buffer;
+  SilcUInt16 remote_port = 0;
+  SilcID id;
+  int coff = 0;
 
   SILC_LOG_DEBUG(("Start"));
 
+  ske->retry_timer = SILC_SKE_RETRY_MIN;
+  silc_schedule_task_del_by_context(ske->schedule, ske);
+
   if (ske->aborted) {
     /** Aborted */
+    silc_packet_free(ske->packet);
+    ske->packet = NULL;
     silc_fsm_next(fsm, silc_ske_st_initiator_aborted);
     return SILC_FSM_CONTINUE;
   }
 
+  /* See if received failure from remote */
+  if (ske->packet->type == SILC_PACKET_FAILURE) {
+    silc_fsm_next(fsm, silc_ske_st_initiator_failure);
+    return SILC_FSM_CONTINUE;
+  }
+
+  if (ske->packet->type != SILC_PACKET_KEY_EXCHANGE) {
+    SILC_LOG_DEBUG(("Remote retransmitted an old packet"));
+    silc_packet_free(ske->packet);
+    ske->packet = NULL;
+    return SILC_FSM_WAIT;
+  }
+
   /* Decode the payload */
   status = silc_ske_payload_start_decode(ske, packet_buf, &payload);
   if (status != SILC_SKE_STATUS_OK) {
     /** Error decoding Start Payload */
+    silc_packet_free(ske->packet);
+    ske->packet = NULL;
     ske->status = status;
     silc_fsm_next(fsm, silc_ske_st_initiator_error);
     return SILC_FSM_CONTINUE;
   }
 
-  /* Check that the cookie is returned unmodified */
-  if (memcmp(ske->start_payload->cookie, payload->cookie,
-            ske->start_payload->cookie_len)) {
+  /* Get remote ID and set it to stream */
+  if (ske->packet->src_id_len) {
+    silc_id_str2id(ske->packet->src_id, ske->packet->src_id_len,
+                  ske->packet->src_id_type,
+                  (ske->packet->src_id_type == SILC_ID_SERVER ?
+                   (void *)&id.u.server_id : (void *)&id.u.client_id),
+                  (ske->packet->src_id_type == SILC_ID_SERVER ?
+                   sizeof(id.u.server_id) : sizeof(id.u.client_id)));
+    silc_packet_set_ids(ske->stream, 0, NULL, ske->packet->src_id_type,
+                       (ske->packet->src_id_type == SILC_ID_SERVER ?
+                        (void *)&id.u.server_id : (void *)&id.u.client_id));
+  }
+
+  silc_packet_free(ske->packet);
+  ske->packet = NULL;
+
+  /* Check that the cookie is returned unmodified.  In case IV included
+     flag and session port has been set, the first two bytes of cookie
+     are the session port and we ignore them in this check. */
+  if (payload->flags & SILC_SKE_SP_FLAG_IV_INCLUDED && ske->session_port) {
+    /* Take remote port */
+    SILC_GET16_MSB(remote_port, ske->start_payload->cookie);
+    coff = 2;
+  }
+  if (memcmp(ske->start_payload->cookie + coff, payload->cookie + coff,
+            SILC_SKE_COOKIE_LEN - coff)) {
     /** Invalid cookie */
-    SILC_LOG_ERROR(("Responder modified our cookie and it must not do it"));
+    SILC_LOG_ERROR(("Invalid cookie, modified or unsupported feature"));
     ske->status = SILC_SKE_STATUS_INVALID_COOKIE;
     silc_fsm_next(fsm, silc_ske_st_initiator_error);
     return SILC_FSM_CONTINUE;
@@ -875,6 +1155,7 @@ SILC_FSM_STATE(silc_ske_st_initiator_phase1)
     goto err;
 
   prop->group = group;
+  prop->remote_port = remote_port;
 
   if (silc_pkcs_find_algorithm(payload->pkcs_alg_list, NULL) == NULL) {
     status = SILC_SKE_STATUS_UNKNOWN_PKCS;
@@ -903,9 +1184,8 @@ SILC_FSM_STATE(silc_ske_st_initiator_phase1)
  err:
   if (payload)
     silc_ske_payload_start_free(payload);
-
-  silc_ske_group_free(group);
-
+  if (group)
+    silc_ske_group_free(group);
   if (prop->cipher)
     silc_cipher_free(prop->cipher);
   if (prop->hash)
@@ -980,22 +1260,20 @@ SILC_FSM_STATE(silc_ske_st_initiator_phase2)
                  &ske->prop->group->group);
 
   /* Get public key */
-  if (ske->public_key) {
-    payload->pk_data = silc_pkcs_public_key_encode(ske->public_key, &pk_len);
-    if (!payload->pk_data) {
-      /** Error encoding public key */
-      silc_mp_uninit(x);
-      silc_free(x);
-      silc_mp_uninit(&payload->x);
-      silc_free(payload);
-      ske->ke1_payload = NULL;
-      ske->status = SILC_SKE_STATUS_ERROR;
-      silc_fsm_next(fsm, silc_ske_st_initiator_error);
-      return SILC_FSM_CONTINUE;
-    }
-    payload->pk_len = pk_len;
+  payload->pk_data = silc_pkcs_public_key_encode(ske->public_key, &pk_len);
+  if (!payload->pk_data) {
+    /** Error encoding public key */
+    silc_mp_uninit(x);
+    silc_free(x);
+    silc_mp_uninit(&payload->x);
+    silc_free(payload);
+    ske->ke1_payload = NULL;
+    ske->status = SILC_SKE_STATUS_ERROR;
+    silc_fsm_next(fsm, silc_ske_st_initiator_error);
+    return SILC_FSM_CONTINUE;
   }
-  payload->pk_type = ske->pk_type;
+  payload->pk_len = pk_len;
+  payload->pk_type = silc_pkcs_get_type(ske->public_key);
 
   /* Compute signature data if we are doing mutual authentication */
   if (ske->private_key &&
@@ -1027,7 +1305,8 @@ SILC_FSM_STATE(silc_ske_st_initiator_phase2)
       return SILC_FSM_CONTINUE;
     }
     payload->sign_data = silc_memdup(sign, sign_len);
-    payload->sign_len = sign_len;
+    if (payload->sign_data)
+      payload->sign_len = sign_len;
     memset(sign, 0, sizeof(sign));
   }
 
@@ -1048,8 +1327,18 @@ SILC_FSM_STATE(silc_ske_st_initiator_phase2)
 
   ske->x = x;
 
+  /* Check for backwards compatibility */
+
   /* Send the packet. */
-  /* XXX */
+  if (!silc_ske_packet_send(ske, SILC_PACKET_KEY_EXCHANGE_1, 0,
+                           silc_buffer_data(payload_buf),
+                           silc_buffer_len(payload_buf))) {
+    /** Error sending packet */
+    SILC_LOG_DEBUG(("Error sending packet"));
+    ske->status = SILC_SKE_STATUS_ERROR;
+    silc_fsm_next(fsm, silc_ske_st_initiator_error);
+    return SILC_FSM_CONTINUE;
+  }
 
   silc_buffer_free(payload_buf);
 
@@ -1070,23 +1359,45 @@ SILC_FSM_STATE(silc_ske_st_initiator_phase3)
 
   SILC_LOG_DEBUG(("Start"));
 
+  ske->retry_timer = SILC_SKE_RETRY_MIN;
+  silc_schedule_task_del_by_context(ske->schedule, ske);
+
   if (ske->aborted) {
     /** Aborted */
+    silc_packet_free(ske->packet);
+    ske->packet = NULL;
     silc_fsm_next(fsm, silc_ske_st_initiator_aborted);
     return SILC_FSM_CONTINUE;
   }
 
+  /* See if received failure from remote */
+  if (ske->packet->type == SILC_PACKET_FAILURE) {
+    silc_fsm_next(fsm, silc_ske_st_initiator_failure);
+    return SILC_FSM_CONTINUE;
+  }
+
+  if (ske->packet->type != SILC_PACKET_KEY_EXCHANGE_2) {
+    SILC_LOG_DEBUG(("Remote retransmitted an old packet"));
+    silc_packet_free(ske->packet);
+    ske->packet = NULL;
+    return SILC_FSM_WAIT;
+  }
+
   /* Decode the payload */
   status = silc_ske_payload_ke_decode(ske, packet_buf, &payload);
   if (status != SILC_SKE_STATUS_OK) {
     /** Error decoding KE payload */
+    silc_packet_free(ske->packet);
+    ske->packet = NULL;
     ske->status = status;
     silc_fsm_next(fsm, silc_ske_st_initiator_error);
     return SILC_FSM_CONTINUE;
   }
+  silc_packet_free(ske->packet);
+  ske->packet = NULL;
   ske->ke2_payload = payload;
 
-  if (!payload->pk_data && ske->callbacks->verify_key) {
+  if (!payload->pk_data && (ske->callbacks->verify_key || ske->repository)) {
     SILC_LOG_DEBUG(("Remote end did not send its public key (or certificate), "
                    "even though we require it"));
     ske->status = SILC_SKE_STATUS_PUBLIC_KEY_NOT_PROVIDED;
@@ -1111,16 +1422,36 @@ SILC_FSM_STATE(silc_ske_st_initiator_phase3)
     goto err;
   }
 
-  if (ske->prop->public_key && ske->callbacks->verify_key) {
+  if (ske->prop->public_key && (ske->callbacks->verify_key ||
+                               ske->repository)) {
     SILC_LOG_DEBUG(("Verifying public key"));
 
     /** Waiting public key verification */
     silc_fsm_next(fsm, silc_ske_st_initiator_phase4);
-    SILC_FSM_CALL(ske->callbacks->verify_key(ske,
-                                            payload->pk_type,
-                                            ske->prop->public_key,
-                                            ske->callbacks->context,
-                                            silc_ske_pk_verified, NULL));
+
+    /* If repository is provided, verify the key from there. */
+    if (ske->repository) {
+      SilcSKRFind find;
+
+      find = silc_skr_find_alloc();
+      if (!find) {
+       status = SILC_SKE_STATUS_OUT_OF_MEMORY;
+       goto err;
+      }
+      silc_skr_find_set_pkcs_type(find,
+                                 silc_pkcs_get_type(ske->prop->public_key));
+      silc_skr_find_set_public_key(find, ske->prop->public_key);
+      silc_skr_find_set_usage(find, SILC_SKR_USAGE_KEY_AGREEMENT);
+
+      /* Find key from repository */
+      SILC_FSM_CALL(silc_skr_find(ske->repository, find,
+                                 silc_ske_skr_callback, ske));
+    } else {
+      /* Verify from application */
+      SILC_FSM_CALL(ske->callbacks->verify_key(ske, ske->prop->public_key,
+                                              ske->callbacks->context,
+                                              silc_ske_pk_verified, NULL));
+    }
     /* NOT REACHED */
   }
 
@@ -1180,14 +1511,11 @@ SILC_FSM_STATE(silc_ske_st_initiator_phase4)
     if (status != SILC_SKE_STATUS_OK)
       goto err;
 
-    ske->hash = silc_memdup(hash, hash_len);
-    ske->hash_len = hash_len;
-
     SILC_LOG_DEBUG(("Verifying signature (HASH)"));
 
     /* Verify signature */
     if (!silc_pkcs_verify(ske->prop->public_key, payload->sign_data,
-                        payload->sign_len, hash, hash_len, NULL)) {
+                         payload->sign_len, hash, hash_len, NULL)) {
       SILC_LOG_ERROR(("Signature verification failed, incorrect signature"));
       status = SILC_SKE_STATUS_INCORRECT_SIGNATURE;
       goto err;
@@ -1195,6 +1523,8 @@ SILC_FSM_STATE(silc_ske_st_initiator_phase4)
 
     SILC_LOG_DEBUG(("Signature is Ok"));
 
+    ske->hash = silc_memdup(hash, hash_len);
+    ske->hash_len = hash_len;
     memset(hash, 'F', hash_len);
   }
 
@@ -1213,7 +1543,14 @@ SILC_FSM_STATE(silc_ske_st_initiator_phase4)
   }
 
   /* Send SUCCESS packet */
-  /* XXX */
+  SILC_PUT32_MSB((SilcUInt32)SILC_SKE_STATUS_OK, hash);
+  if (!silc_ske_packet_send(ske, SILC_PACKET_SUCCESS, 0, hash, 4)) {
+    /** Error sending packet */
+    SILC_LOG_DEBUG(("Error sending packet"));
+    ske->status = SILC_SKE_STATUS_ERROR;
+    silc_fsm_next(fsm, silc_ske_st_initiator_error);
+    return SILC_FSM_CONTINUE;
+  }
 
   /** Waiting completion */
   silc_fsm_next(fsm, silc_ske_st_initiator_end);
@@ -1249,15 +1586,41 @@ SILC_FSM_STATE(silc_ske_st_initiator_end)
 {
   SilcSKE ske = fsm_context;
 
+  SILC_LOG_DEBUG(("Start"));
+
+  ske->retry_timer = SILC_SKE_RETRY_MIN;
+  silc_schedule_task_del_by_context(ske->schedule, ske);
+
   if (ske->aborted) {
     /** Aborted */
     silc_fsm_next(fsm, silc_ske_st_initiator_aborted);
     return SILC_FSM_CONTINUE;
   }
 
+  /* See if received failure from remote */
+  if (ske->packet->type == SILC_PACKET_FAILURE) {
+    silc_fsm_next(fsm, silc_ske_st_initiator_failure);
+    return SILC_FSM_CONTINUE;
+  }
+
+  if (ske->packet->type != SILC_PACKET_SUCCESS) {
+    SILC_LOG_DEBUG(("Remote retransmitted an old packet"));
+    silc_packet_free(ske->packet);
+    ske->packet = NULL;
+    return SILC_FSM_WAIT;
+  }
+
+  SILC_LOG_DEBUG(("Key exchange completed successfully"));
+
   /* Call the completion callback */
   if (ske->callbacks->completed)
-    ske->callbacks->completed(ske, ske->status, NULL, NULL, NULL, NULL);
+    ske->callbacks->completed(ske, ske->status, ske->prop, ske->keymat,
+                             ske->rekey, ske->callbacks->context);
+
+  silc_packet_free(ske->packet);
+  ske->packet = NULL;
+  silc_packet_stream_unlink(ske->stream, &silc_ske_stream_cbs, ske);
+  silc_schedule_task_del_by_context(ske->schedule, ske);
 
   return SILC_FSM_FINISH;
 }
@@ -1266,23 +1629,88 @@ SILC_FSM_STATE(silc_ske_st_initiator_end)
 
 SILC_FSM_STATE(silc_ske_st_initiator_aborted)
 {
+  SilcSKE ske = fsm_context;
+  unsigned char data[4];
+
+  SILC_LOG_DEBUG(("Aborted by caller"));
+
+  /* Send FAILURE packet */
+  SILC_PUT32_MSB(SILC_SKE_STATUS_ERROR, data);
+  silc_ske_packet_send(ske, SILC_PACKET_FAILURE, 0, data, 4);
+  silc_packet_stream_unlink(ske->stream, &silc_ske_stream_cbs, ske);
+  silc_schedule_task_del_by_context(ske->schedule, ske);
 
   return SILC_FSM_FINISH;
 }
 
-/* Error occurred */
+/* Error occurred.  Send error to remote host */
 
 SILC_FSM_STATE(silc_ske_st_initiator_error)
 {
+  SilcSKE ske = fsm_context;
+  SilcSKEStatus status;
+  unsigned char data[4];
+
+  SILC_LOG_DEBUG(("Error %s (%d) occurred during key exchange",
+                 silc_ske_map_status(ske->status), ske->status));
+
+  status = ske->status;
+  if (status > SILC_SKE_STATUS_INVALID_COOKIE)
+    status = SILC_SKE_STATUS_ERROR;
+
+  /* Send FAILURE packet */
+  SILC_PUT32_MSB((SilcUInt32)status, data);
+  silc_ske_packet_send(ske, SILC_PACKET_FAILURE, 0, data, 4);
+
+  /* Call the completion callback */
+  if (!ske->aborted && ske->callbacks->completed)
+    ske->callbacks->completed(ske, ske->status, NULL, NULL, NULL,
+                             ske->callbacks->context);
+
+  silc_packet_stream_unlink(ske->stream, &silc_ske_stream_cbs, ske);
+  silc_schedule_task_del_by_context(ske->schedule, ske);
+
+  return SILC_FSM_FINISH;
+}
+
+/* Failure received from remote */
+
+SILC_FSM_STATE(silc_ske_st_initiator_failure)
+{
+  SilcSKE ske = fsm_context;
+  SilcUInt32 error = SILC_SKE_STATUS_ERROR;
+
+  SILC_LOG_DEBUG(("Error %s (%d) received during key exchange",
+                 silc_ske_map_status(ske->status), ske->status));
+
+  if (ske->packet && silc_buffer_len(&ske->packet->buffer) == 4) {
+    SILC_GET32_MSB(error, ske->packet->buffer.data);
+    ske->status = error;
+    silc_packet_free(ske->packet);
+    ske->packet = NULL;
+  }
+
+  /* Call the completion callback */
+  if (!ske->aborted && ske->callbacks->completed)
+    ske->callbacks->completed(ske, ske->status, NULL, NULL, NULL,
+                             ske->callbacks->context);
+
+  silc_packet_stream_unlink(ske->stream, &silc_ske_stream_cbs, ske);
+  silc_schedule_task_del_by_context(ske->schedule, ske);
 
   return SILC_FSM_FINISH;
 }
 
+/* FSM destructor */
 
 static void silc_ske_initiator_finished(SilcFSM fsm, void *fsm_context,
                                        void *destructor_context)
 {
+  SilcSKE ske = fsm_context;
 
+  ske->running = FALSE;
+  if (ske->freed)
+    silc_ske_free(ske);
 }
 
 /* Starts the protocol as initiator */
@@ -1290,11 +1718,12 @@ static void silc_ske_initiator_finished(SilcFSM fsm, void *fsm_context,
 SilcAsyncOperation
 silc_ske_initiator(SilcSKE ske,
                   SilcPacketStream stream,
+                  SilcSKEParams params,
                   SilcSKEStartPayload start_payload)
 {
   SILC_LOG_DEBUG(("Start SKE as initiator"));
 
-  if (!ske || !stream || !start_payload)
+  if (!ske || !stream || !params || !params->version)
     return NULL;
 
   if (!silc_async_init(&ske->op, silc_ske_abort, NULL, ske))
@@ -1304,7 +1733,21 @@ silc_ske_initiator(SilcSKE ske,
                     ske->schedule))
     return NULL;
 
+  if (params->flags & SILC_SKE_SP_FLAG_IV_INCLUDED)
+    ske->session_port = params->session_port;
+
+  /* Generate security properties if not provided */
+  if (!start_payload) {
+    start_payload = silc_ske_assemble_security_properties(ske,
+                                                         params->flags,
+                                                         params->version);
+    if (!start_payload)
+      return NULL;
+  }
+
   ske->start_payload = start_payload;
+  ske->version = params->version;
+  ske->running = TRUE;
 
   /* Link to packet stream to get key exchange packets */
   ske->stream = stream;
@@ -1320,20 +1763,8 @@ silc_ske_initiator(SilcSKE ske,
   return &ske->op;
 }
 
-
 /******************************** Responder *********************************/
 
-SILC_FSM_STATE(silc_ske_st_responder_start);
-SILC_FSM_STATE(silc_ske_st_responder_phase1);
-SILC_FSM_STATE(silc_ske_st_responder_phase2);
-SILC_FSM_STATE(silc_ske_st_responder_phase3);
-SILC_FSM_STATE(silc_ske_st_responder_phase4);
-SILC_FSM_STATE(silc_ske_st_responder_phase5);
-SILC_FSM_STATE(silc_ske_st_responder_end);
-SILC_FSM_STATE(silc_ske_st_responder_aborted);
-SILC_FSM_STATE(silc_ske_st_responder_failure);
-SILC_FSM_STATE(silc_ske_st_responder_error);
-
 /* Start protocol as responder.  Wait initiator's start payload */
 
 SILC_FSM_STATE(silc_ske_st_responder_start)
@@ -1356,19 +1787,22 @@ SILC_FSM_STATE(silc_ske_st_responder_start)
   return SILC_FSM_WAIT;
 }
 
-/* Decode initiator's start payload */
+/* Decode initiator's start payload.  Select the security properties from
+   the initiator's start payload and send our reply start payload back. */
 
 SILC_FSM_STATE(silc_ske_st_responder_phase1)
 {
   SilcSKE ske = fsm_context;
   SilcSKEStatus status;
-  SilcSKEStartPayload remote_payload = NULL, payload = NULL;
+  SilcSKEStartPayload remote_payload = NULL;
   SilcBuffer packet_buf = &ske->packet->buffer;
 
   SILC_LOG_DEBUG(("Start"));
 
   if (ske->aborted) {
     /** Aborted */
+    silc_packet_free(ske->packet);
+    ske->packet = NULL;
     silc_fsm_next(fsm, silc_ske_st_responder_aborted);
     return SILC_FSM_CONTINUE;
   }
@@ -1384,6 +1818,7 @@ SILC_FSM_STATE(silc_ske_st_responder_phase1)
   if (status != SILC_SKE_STATUS_OK) {
     /** Error decoding Start Payload */
     silc_packet_free(ske->packet);
+    ske->packet = NULL;
     ske->status = status;
     silc_fsm_next(fsm, silc_ske_st_responder_error);
     return SILC_FSM_CONTINUE;
@@ -1394,6 +1829,7 @@ SILC_FSM_STATE(silc_ske_st_responder_phase1)
   ske->start_payload_copy = silc_buffer_copy(packet_buf);
 
   silc_packet_free(ske->packet);
+  ske->packet = NULL;
 
   /* Force the mutual authentication flag if we want to do it. */
   if (ske->flags & SILC_SKE_SP_FLAG_MUTUAL) {
@@ -1414,106 +1850,47 @@ SILC_FSM_STATE(silc_ske_st_responder_phase1)
     remote_payload->flags &= ~SILC_SKE_SP_FLAG_IV_INCLUDED;
   }
 
-  /* Parse and select the security properties from the payload */
-  payload = silc_calloc(1, sizeof(*payload));
-  status = silc_ske_select_security_properties(ske, payload, remote_payload);
+  /* Check and select security properties */
+  status = silc_ske_select_security_properties(ske, remote_payload,
+                                              &ske->prop);
   if (status != SILC_SKE_STATUS_OK) {
     /** Error selecting proposal */
-    if (remote_payload)
-      silc_ske_payload_start_free(remote_payload);
-    silc_free(payload);
+    silc_ske_payload_start_free(remote_payload);
     ske->status = status;
     silc_fsm_next(fsm, silc_ske_st_responder_error);
     return SILC_FSM_CONTINUE;
   }
 
-  ske->start_payload = payload;
-
   silc_ske_payload_start_free(remote_payload);
 
-  /** Send proposal to initiator */
-  silc_fsm_next(fsm, silc_ske_st_responder_phase2);
-  return SILC_FSM_CONTINUE;
-}
-
-/* Phase-2.  Send Start Payload */
-
-SILC_FSM_STATE(silc_ske_st_responder_phase2)
-{
-  SilcSKE ske = fsm_context;
-  SilcSKEStatus status;
-  SilcBuffer payload_buf;
-  SilcSKESecurityProperties prop;
-  SilcSKEDiffieHellmanGroup group = NULL;
-
-  SILC_LOG_DEBUG(("Start"));
-
-  /* Allocate security properties from the payload. These are allocated
-     only for this negotiation and will be free'd after KE is over. */
-  ske->prop = prop = silc_calloc(1, sizeof(*prop));
-  if (!ske->prop) {
-    status = SILC_SKE_STATUS_OUT_OF_MEMORY;
-    goto err;
-  }
-  prop->flags = ske->start_payload->flags;
-  status = silc_ske_group_get_by_name(ske->start_payload->ke_grp_list,
-                                     &group);
-  if (status != SILC_SKE_STATUS_OK)
-    goto err;
-
-  prop->group = group;
-
-  /* XXX these shouldn't be allocated before we know the remote's
-     public key type.  It's unnecessary to allocate these because the
-     select_security_properties has succeeded already. */
-  if (!silc_pkcs_find_algorithm(ske->start_payload->pkcs_alg_list, NULL)) {
-    status = SILC_SKE_STATUS_UNKNOWN_PKCS;
-    goto err;
-  }
-  if (silc_cipher_alloc(ske->start_payload->enc_alg_list,
-                       &prop->cipher) == FALSE) {
-    status = SILC_SKE_STATUS_UNKNOWN_CIPHER;
-    goto err;
-  }
-  if (silc_hash_alloc(ske->start_payload->hash_alg_list,
-                     &prop->hash) == FALSE) {
-    status = SILC_SKE_STATUS_UNKNOWN_HASH_FUNCTION;
-    goto err;
-  }
-  if (silc_hmac_alloc(ske->start_payload->hmac_alg_list, NULL,
-                     &prop->hmac) == FALSE) {
-    status = SILC_SKE_STATUS_UNKNOWN_HMAC;
-    goto err;
-  }
-
-  /* Encode the payload */
+  /* Encode our reply payload to send the selected security properties */
   status = silc_ske_payload_start_encode(ske, ske->start_payload,
-                                        &payload_buf);
+                                        &packet_buf);
   if (status != SILC_SKE_STATUS_OK)
     goto err;
 
   /* Send the packet. */
-  if (!silc_packet_send(ske->stream, SILC_PACKET_KEY_EXCHANGE, 0,
-                       payload_buf->data, silc_buffer_len(payload_buf)))
+  if (!silc_ske_packet_send(ske, SILC_PACKET_KEY_EXCHANGE, 0,
+                           silc_buffer_data(packet_buf),
+                           silc_buffer_len(packet_buf)))
     goto err;
 
-  silc_buffer_free(payload_buf);
+  silc_buffer_free(packet_buf);
 
   /** Waiting initiator's KE payload */
-  silc_fsm_next(fsm, silc_ske_st_responder_phase3);
+  silc_fsm_next(fsm, silc_ske_st_responder_phase2);
   return SILC_FSM_WAIT;
 
  err:
-  if (group)
-    silc_ske_group_free(group);
-
-  if (prop->cipher)
-    silc_cipher_free(prop->cipher);
-  if (prop->hash)
-    silc_hash_free(prop->hash);
-  if (prop->hmac)
-    silc_hmac_free(prop->hmac);
-  silc_free(prop);
+  if (ske->prop->group)
+    silc_ske_group_free(ske->prop->group);
+  if (ske->prop->cipher)
+    silc_cipher_free(ske->prop->cipher);
+  if (ske->prop->hash)
+    silc_hash_free(ske->prop->hash);
+  if (ske->prop->hmac)
+    silc_hmac_free(ske->prop->hmac);
+  silc_free(ske->prop);
   ske->prop = NULL;
 
   if (status == SILC_SKE_STATUS_OK)
@@ -1525,9 +1902,9 @@ SILC_FSM_STATE(silc_ske_st_responder_phase2)
   return SILC_FSM_CONTINUE;
 }
 
-/* Phase-3.  Decode initiator's KE payload */
+/* Phase-2.  Decode initiator's KE payload */
 
-SILC_FSM_STATE(silc_ske_st_responder_phase3)
+SILC_FSM_STATE(silc_ske_st_responder_phase2)
 {
   SilcSKE ske = fsm_context;
   SilcSKEStatus status;
@@ -1536,6 +1913,9 @@ SILC_FSM_STATE(silc_ske_st_responder_phase3)
 
   SILC_LOG_DEBUG(("Start"));
 
+  ske->retry_timer = SILC_SKE_RETRY_MIN;
+  silc_schedule_task_del_by_context(ske->schedule, ske);
+
   if (ske->aborted) {
     /** Aborted */
     silc_fsm_next(fsm, silc_ske_st_responder_aborted);
@@ -1548,11 +1928,19 @@ SILC_FSM_STATE(silc_ske_st_responder_phase3)
     return SILC_FSM_CONTINUE;
   }
 
+  if (ske->packet->type != SILC_PACKET_KEY_EXCHANGE_1) {
+    SILC_LOG_DEBUG(("Remote retransmitted an old packet"));
+    silc_packet_free(ske->packet);
+    ske->packet = NULL;
+    return SILC_FSM_WAIT;
+  }
+
   /* Decode Key Exchange Payload */
   status = silc_ske_payload_ke_decode(ske, packet_buf, &recv_payload);
   if (status != SILC_SKE_STATUS_OK) {
     /** Error decoding KE payload */
     silc_packet_free(ske->packet);
+    ske->packet = NULL;
     ske->status = status;
     silc_fsm_next(fsm, silc_ske_st_responder_error);
     return SILC_FSM_CONTINUE;
@@ -1561,6 +1949,7 @@ SILC_FSM_STATE(silc_ske_st_responder_phase3)
   ske->ke1_payload = recv_payload;
 
   silc_packet_free(ske->packet);
+  ske->packet = NULL;
 
   /* Verify the received public key and verify the signature if we are
      doing mutual authentication. */
@@ -1569,7 +1958,8 @@ SILC_FSM_STATE(silc_ske_st_responder_phase3)
 
     SILC_LOG_DEBUG(("We are doing mutual authentication"));
 
-    if (!recv_payload->pk_data && ske->callbacks->verify_key) {
+    if (!recv_payload->pk_data && (ske->callbacks->verify_key ||
+                                  ske->repository)) {
       /** Public key not provided */
       SILC_LOG_ERROR(("Remote end did not send its public key (or "
                      "certificate), even though we require it"));
@@ -1591,16 +1981,37 @@ SILC_FSM_STATE(silc_ske_st_responder_phase3)
       return SILC_FSM_CONTINUE;
     }
 
-    if (ske->prop->public_key && ske->callbacks->verify_key) {
+    if (ske->prop->public_key && (ske->callbacks->verify_key ||
+                                 ske->repository)) {
       SILC_LOG_DEBUG(("Verifying public key"));
 
       /** Waiting public key verification */
       silc_fsm_next(fsm, silc_ske_st_responder_phase4);
-      SILC_FSM_CALL(ske->callbacks->verify_key(ske,
-                                              recv_payload->pk_type,
-                                              ske->prop->public_key,
-                                              ske->callbacks->context,
-                                              silc_ske_pk_verified, NULL));
+
+      /* If repository is provided, verify the key from there. */
+      if (ske->repository) {
+       SilcSKRFind find;
+
+       find = silc_skr_find_alloc();
+       if (!find) {
+         ske->status = SILC_SKE_STATUS_OUT_OF_MEMORY;
+         silc_fsm_next(fsm, silc_ske_st_responder_error);
+         return SILC_FSM_CONTINUE;
+       }
+       silc_skr_find_set_pkcs_type(find,
+                                   silc_pkcs_get_type(ske->prop->public_key));
+       silc_skr_find_set_public_key(find, ske->prop->public_key);
+       silc_skr_find_set_usage(find, SILC_SKR_USAGE_KEY_AGREEMENT);
+
+       /* Find key from repository */
+       SILC_FSM_CALL(silc_skr_find(ske->repository, find,
+                                   silc_ske_skr_callback, ske));
+      } else {
+       /* Verify from application */
+       SILC_FSM_CALL(ske->callbacks->verify_key(ske, ske->prop->public_key,
+                                                ske->callbacks->context,
+                                                silc_ske_pk_verified, NULL));
+      }
       /* NOT REACHED */
     }
   }
@@ -1767,7 +2178,7 @@ SILC_FSM_STATE(silc_ske_st_responder_phase5)
     ske->ke2_payload->sign_len = sign_len;
     memset(sign, 0, sizeof(sign));
   }
-  ske->ke2_payload->pk_type = ske->pk_type;
+  ske->ke2_payload->pk_type = silc_pkcs_get_type(ske->public_key);
 
   /* Encode the Key Exchange Payload */
   status = silc_ske_payload_ke_encode(ske, ske->ke2_payload,
@@ -1780,8 +2191,9 @@ SILC_FSM_STATE(silc_ske_st_responder_phase5)
   }
 
   /* Send the packet. */
-  if (!silc_packet_send(ske->stream, SILC_PACKET_KEY_EXCHANGE_2, 0,
-                       payload_buf->data, silc_buffer_len(payload_buf))) {
+  if (!silc_ske_packet_send(ske, SILC_PACKET_KEY_EXCHANGE_2, 0,
+                           payload_buf->data, silc_buffer_len(payload_buf))) {
+    SILC_LOG_DEBUG(("Error sending packet"));
     ske->status = SILC_SKE_STATUS_ERROR;
     silc_fsm_next(fsm, silc_ske_st_responder_error);
     return SILC_FSM_CONTINUE;
@@ -1802,6 +2214,9 @@ SILC_FSM_STATE(silc_ske_st_responder_end)
   unsigned char tmp[4];
   SilcUInt32 hash_len, key_len, block_len;
 
+  ske->retry_timer = SILC_SKE_RETRY_MIN;
+  silc_schedule_task_del_by_context(ske->schedule, ske);
+
   if (ske->aborted) {
     /** Aborted */
     silc_fsm_next(fsm, silc_ske_st_responder_aborted);
@@ -1813,7 +2228,15 @@ SILC_FSM_STATE(silc_ske_st_responder_end)
     silc_fsm_next(fsm, silc_ske_st_responder_failure);
     return SILC_FSM_CONTINUE;
   }
+
+  if (ske->packet->type != SILC_PACKET_SUCCESS) {
+    SILC_LOG_DEBUG(("Remote retransmitted an old packet"));
+    silc_packet_free(ske->packet);
+    ske->packet = NULL;
+    return SILC_FSM_WAIT;
+  }
   silc_packet_free(ske->packet);
+  ske->packet = NULL;
 
   /* Process key material */
   key_len = silc_cipher_get_key_len(ske->prop->cipher);
@@ -1830,9 +2253,10 @@ SILC_FSM_STATE(silc_ske_st_responder_end)
 
   /* Send SUCCESS packet */
   SILC_PUT32_MSB(SILC_SKE_STATUS_OK, tmp);
-  silc_packet_send(ske->stream, SILC_PACKET_SUCCESS, 0, tmp, 4);
+  silc_ske_packet_send(ske, SILC_PACKET_SUCCESS, 0, tmp, 4);
 
   silc_packet_stream_unlink(ske->stream, &silc_ske_stream_cbs, ske);
+  silc_schedule_task_del_by_context(ske->schedule, ske);
 
   /* Call the completion callback */
   if (ske->callbacks->completed)
@@ -1853,9 +2277,10 @@ SILC_FSM_STATE(silc_ske_st_responder_aborted)
 
   /* Send FAILURE packet */
   SILC_PUT32_MSB(SILC_SKE_STATUS_ERROR, tmp);
-  silc_packet_send(ske->stream, SILC_PACKET_FAILURE, 0, tmp, 4);
+  silc_ske_packet_send(ske, SILC_PACKET_FAILURE, 0, tmp, 4);
 
   silc_packet_stream_unlink(ske->stream, &silc_ske_stream_cbs, ske);
+  silc_schedule_task_del_by_context(ske->schedule, ske);
 
   return SILC_FSM_FINISH;
 }
@@ -1869,17 +2294,20 @@ SILC_FSM_STATE(silc_ske_st_responder_failure)
 
   SILC_LOG_DEBUG(("Key exchange protocol failed"));
 
-  if (silc_buffer_len(&ske->packet->buffer) == 4)
+  if (ske->packet && silc_buffer_len(&ske->packet->buffer) == 4) {
     SILC_GET32_MSB(error, ske->packet->buffer.data);
-  ske->status = error;
+    ske->status = error;
+    silc_packet_free(ske->packet);
+    ske->packet = NULL;
+  }
 
   /* Call the completion callback */
-  if (ske->callbacks->completed)
+  if (!ske->aborted && ske->callbacks->completed)
     ske->callbacks->completed(ske, ske->status, NULL, NULL, NULL,
                              ske->callbacks->context);
 
-  silc_packet_free(ske->packet);
   silc_packet_stream_unlink(ske->stream, &silc_ske_stream_cbs, ske);
+  silc_schedule_task_del_by_context(ske->schedule, ske);
 
   return SILC_FSM_FINISH;
 }
@@ -1898,9 +2326,9 @@ SILC_FSM_STATE(silc_ske_st_responder_error)
   if (ske->status > SILC_SKE_STATUS_INVALID_COOKIE)
     ske->status = SILC_SKE_STATUS_BAD_PAYLOAD;
   SILC_PUT32_MSB(ske->status, tmp);
-  silc_packet_send(ske->stream, SILC_PACKET_FAILURE, 0, tmp, 4);
-
+  silc_ske_packet_send(ske, SILC_PACKET_FAILURE, 0, tmp, 4);
   silc_packet_stream_unlink(ske->stream, &silc_ske_stream_cbs, ske);
+  silc_schedule_task_del_by_context(ske->schedule, ske);
 
   return SILC_FSM_FINISH;
 }
@@ -1909,7 +2337,11 @@ SILC_FSM_STATE(silc_ske_st_responder_error)
 static void silc_ske_responder_finished(SilcFSM fsm, void *fsm_context,
                                        void *destructor_context)
 {
+  SilcSKE ske = fsm_context;
 
+  ske->running = FALSE;
+  if (ske->freed)
+    silc_ske_free(ske);
 }
 
 /* Starts the protocol as responder. */
@@ -1917,12 +2349,11 @@ static void silc_ske_responder_finished(SilcFSM fsm, void *fsm_context,
 SilcAsyncOperation
 silc_ske_responder(SilcSKE ske,
                   SilcPacketStream stream,
-                  const char *version,
-                  SilcSKESecurityPropertyFlag flags)
+                  SilcSKEParams params)
 {
   SILC_LOG_DEBUG(("Start SKE as responder"));
 
-  if (!ske || !stream || !version) {
+  if (!ske || !stream || !params || !params->version) {
     return NULL;
   }
 
@@ -1933,11 +2364,14 @@ silc_ske_responder(SilcSKE ske,
                     ske->schedule))
     return NULL;
 
-  ske->flags = flags;
-  ske->version = strdup(version);
+  ske->responder = TRUE;
+  ske->flags = params->flags;
+  if (ske->flags & SILC_SKE_SP_FLAG_IV_INCLUDED)
+    ske->session_port = params->session_port;
+  ske->version = strdup(params->version);
   if (!ske->version)
     return NULL;
-  ske->responder = TRUE;
+  ske->running = TRUE;
 
   /* Link to packet stream to get key exchange packets */
   ske->stream = stream;
@@ -2029,67 +2463,6 @@ silc_ske_rekey_responder(SilcSKE ske,
   return &ske->op;
 }
 
-/* Assembles security properties */
-
-SilcSKEStartPayload
-silc_ske_assemble_security_properties(SilcSKE ske,
-                                     SilcSKESecurityPropertyFlag flags,
-                                     const char *version)
-{
-  SilcSKEStartPayload rp;
-  int i;
-
-  SILC_LOG_DEBUG(("Assembling KE Start Payload"));
-
-  rp = silc_calloc(1, sizeof(*rp));
-
-  /* Set flags */
-  rp->flags = (unsigned char)flags;
-
-  /* Set random cookie */
-  rp->cookie = silc_calloc(SILC_SKE_COOKIE_LEN, sizeof(*rp->cookie));
-  for (i = 0; i < SILC_SKE_COOKIE_LEN; i++)
-    rp->cookie[i] = silc_rng_get_byte_fast(ske->rng);
-  rp->cookie_len = SILC_SKE_COOKIE_LEN;
-
-  /* Put version */
-  rp->version = strdup(version);
-  rp->version_len = strlen(version);
-
-  /* Get supported Key Exhange groups */
-  rp->ke_grp_list = silc_ske_get_supported_groups();
-  rp->ke_grp_len = strlen(rp->ke_grp_list);
-
-  /* Get supported PKCS algorithms */
-  rp->pkcs_alg_list = silc_pkcs_get_supported();
-  rp->pkcs_alg_len = strlen(rp->pkcs_alg_list);
-
-  /* Get supported encryption algorithms */
-  rp->enc_alg_list = silc_cipher_get_supported();
-  rp->enc_alg_len = strlen(rp->enc_alg_list);
-
-  /* Get supported hash algorithms */
-  rp->hash_alg_list = silc_hash_get_supported();
-  rp->hash_alg_len = strlen(rp->hash_alg_list);
-
-  /* Get supported HMACs */
-  rp->hmac_alg_list = silc_hmac_get_supported();
-  rp->hmac_alg_len = strlen(rp->hmac_alg_list);
-
-  /* XXX */
-  /* Get supported compression algorithms */
-  rp->comp_alg_list = strdup("none");
-  rp->comp_alg_len = strlen("none");
-
-  rp->len = 1 + 1 + 2 + SILC_SKE_COOKIE_LEN +
-    2 + rp->version_len +
-    2 + rp->ke_grp_len + 2 + rp->pkcs_alg_len +
-    2 + rp->enc_alg_len + 2 + rp->hash_alg_len +
-    2 + rp->hmac_alg_len + 2 + rp->comp_alg_len;
-
-  return rp;
-}
-
 /* Processes the provided key material `data' as the SILC protocol
    specification defines. */
 
@@ -2421,12 +2794,6 @@ SilcBool silc_ske_set_keys(SilcSKE ske,
       return FALSE;
   }
 
-  SILC_LOG_INFO(("Security properties: %s %s %s %s",
-                ret_send_key ? silc_cipher_get_name(*ret_send_key) : "??",
-                ret_hmac_send ? silc_hmac_get_name(*ret_hmac_send) : "??",
-                ret_hash ? silc_hash_get_name(*ret_hash) : "??",
-                ske->prop->flags & SILC_SKE_SP_FLAG_PFS ? "PFS" : ""));
-
   return TRUE;
 }
 
@@ -2486,3 +2853,17 @@ SilcBool silc_ske_parse_version(SilcSKE ske,
                                   software_version_string,
                                   vendor_version);
 }
+
+/* Get security properties */
+
+SilcSKESecurityProperties silc_ske_get_security_properties(SilcSKE ske)
+{
+  return ske->prop;
+}
+
+/* Get key material */
+
+SilcSKEKeyMaterial silc_ske_get_key_material(SilcSKE ske)
+{
+  return ske->keymat;
+}