Added preliminary Symbian support.
[silc.git] / lib / silccore / silcpacket.c
index 5f3c55d092ba0c94c75f41ba55c1d2488bc38fcd..6de9eb089a91860680de499226a1a3189e2077bd 100644 (file)
 
 /************************** Types and definitions ***************************/
 
+/* Per scheduler (which usually means per thread) data.  We put per scheduler
+   data here for accessing without locking.  SILC Schedule dictates that
+   tasks are dispatched in one thread, hence the per scheduler context. */
+typedef struct {
+  SilcSchedule schedule;                /* The scheduler */
+  SilcPacketEngine engine;              /* Packet engine */
+  SilcBufferStruct inbuf;               /* Data input buffer */
+  SilcUInt32 stream_count;              /* Number of streams using this */
+} *SilcPacketEngineContext;
+
 /* Packet engine */
 struct SilcPacketEngineStruct {
+  SilcMutex lock;                       /* Engine lock */
   SilcRng rng;                          /* RNG for engine */
+  SilcHashTable contexts;               /* Per scheduler contexts */
   SilcPacketCallbacks *callbacks;       /* Packet callbacks */
   void *callback_context;               /* Context for callbacks */
   SilcList streams;                     /* All streams in engine */
   SilcList packet_pool;                 /* Free list for received packets */
-  SilcMutex lock;                       /* Engine lock */
-  SilcBool local_is_router;
+  SilcHashTable udp_remote;             /* UDP remote streams, or NULL */
+  unsigned int local_is_router    : 1;
 };
 
-/* Packet procesor context */
+/* Packet processor context */
 typedef struct SilcPacketProcessStruct {
-  SilcInt32 priority;                   /* Priority */
   SilcPacketType *types;                /* Packets to process */
   SilcPacketCallbacks *callbacks;       /* Callbacks or NULL */
   void *callback_context;
+  SilcInt32 priority;                   /* Priority */
 } *SilcPacketProcess;
 
+/* UDP remote stream tuple */
+typedef struct {
+  char *remote_ip;                      /* Remote IP address */
+  SilcUInt16 remote_port;               /* Remote port */
+} *SilcPacketRemoteUDP;
+
 /* Packet stream */
 struct SilcPacketStreamStruct {
   struct SilcPacketStreamStruct *next;
-  SilcPacketEngine engine;              /* Packet engine */
+  SilcPacketEngineContext sc;           /* Per scheduler context */
   SilcStream stream;                    /* Underlaying stream */
   SilcMutex lock;                       /* Stream lock */
-  SilcDList process;                    /* Packet processors, it set */
-  SilcHashTable streamers;              /* Valid if streamers exist */
+  SilcDList process;                    /* Packet processors, or NULL */
+  SilcPacketRemoteUDP remote_udp;       /* UDP remote stream tuple, or NULL */
   void *stream_context;                         /* Stream context */
-  SilcBufferStruct inbuf;               /* In buffer */
   SilcBufferStruct outbuf;              /* Out buffer */
-  SilcUInt32 send_psn;                  /* Sending sequence */
-  SilcCipher send_key;                  /* Sending key */
-  SilcHmac send_hmac;                   /* Sending HMAC */
-  SilcUInt32 receive_psn;               /* Receiving sequence */
-  SilcCipher receive_key;               /* Receiving key */
-  SilcHmac receive_hmac;                /* Receiving HMAC */
+  SilcCipher send_key[2];               /* Sending key */
+  SilcHmac send_hmac[2];                /* Sending HMAC */
+  SilcCipher receive_key[2];            /* Receiving key */
+  SilcHmac receive_hmac[2];             /* Receiving HMAC */
   unsigned char *src_id;                /* Source ID */
   unsigned char *dst_id;                /* Destination ID */
+  SilcUInt32 send_psn;                  /* Sending sequence */
+  SilcUInt32 receive_psn;               /* Receiving sequence */
+  SilcAtomic8 refcnt;                   /* Reference counter */
+  SilcUInt8 sid;                        /* Security ID, set if IV included */
   unsigned int src_id_len  : 6;
   unsigned int src_id_type : 2;
   unsigned int dst_id_len  : 6;
   unsigned int dst_id_type : 2;
-  SilcUInt8 refcnt;                     /* Reference counter */
   unsigned int is_router   : 1;                 /* Set if router stream */
   unsigned int destroyed   : 1;                 /* Set if destroyed */
+  unsigned int iv_included : 1;          /* Set if IV included */
+  unsigned int udp         : 1;          /* UDP remote stream */
 };
 
 /* Initial size of stream buffers */
@@ -78,10 +98,9 @@ struct SilcPacketStreamStruct {
 /* Header length without source and destination ID's. */
 #define SILC_PACKET_HEADER_LEN 10
 
-/* Minimum length of SILC Packet Header. This much is decrypted always
-   when packet is received to be able to get all the relevant data out
-   from the header. */
+/* Minimum length of SILC Packet Header. */
 #define SILC_PACKET_MIN_HEADER_LEN 16
+#define SILC_PACKET_MIN_HEADER_LEN_IV 32 + 1
 
 /* Maximum padding length */
 #define SILC_PACKET_MAX_PADLEN 128
@@ -92,9 +111,6 @@ struct SilcPacketStreamStruct {
 /* Minimum packet length */
 #define SILC_PACKET_MIN_LEN (SILC_PACKET_HEADER_LEN + 1)
 
-
-/* Macros */
-
 /* Returns true length of the packet. */
 #define SILC_PACKET_LENGTH(__packetdata, __ret_truelen, __ret_paddedlen) \
 do {                                                                    \
@@ -132,127 +148,288 @@ do {                                                                       \
 /* EOS callback */
 #define SILC_PACKET_CALLBACK_EOS(s)                                    \
 do {                                                                   \
-  (s)->engine->callbacks->eos((s)->engine, s,                          \
-                             (s)->engine->callback_context,            \
-                             (s)->stream_context);                     \
+  (s)->sc->engine->callbacks->eos((s)->sc->engine, s,                  \
+                                 (s)->sc->engine->callback_context,    \
+                                 (s)->stream_context);                 \
 } while(0)
 
 /* Error callback */
 #define SILC_PACKET_CALLBACK_ERROR(s, err)                             \
 do {                                                                   \
-  (s)->engine->callbacks->error((s)->engine, s, err,                   \
-                               (s)->engine->callback_context,          \
-                               (s)->stream_context);                   \
+  (s)->sc->engine->callbacks->error((s)->sc->engine, s, err,           \
+                                   (s)->sc->engine->callback_context,  \
+                                   (s)->stream_context);               \
 } while(0)
 
+static SilcBool silc_packet_dispatch(SilcPacket packet);
+static void silc_packet_read_process(SilcPacketStream stream);
+static inline SilcBool silc_packet_send_raw(SilcPacketStream stream,
+                                           SilcPacketType type,
+                                           SilcPacketFlags flags,
+                                           SilcIdType src_id_type,
+                                           unsigned char *src_id,
+                                           SilcUInt32 src_id_len,
+                                           SilcIdType dst_id_type,
+                                           unsigned char *dst_id,
+                                           SilcUInt32 dst_id_len,
+                                           const unsigned char *data,
+                                           SilcUInt32 data_len,
+                                           SilcCipher cipher,
+                                           SilcHmac hmac);
 
 /************************ Static utility functions **************************/
 
-static void silc_packet_read_process(SilcPacketStream stream);
+/* Injects packet to new stream created with silc_packet_stream_add_remote. */
 
-/* Our stream IO notifier callback. */
+SILC_TASK_CALLBACK(silc_packet_stream_inject_packet)
+{
+  SilcPacket packet = context;
+  SilcPacketStream stream = packet->stream;
 
-static void silc_packet_stream_io(SilcStream stream, SilcStreamStatus status,
-                                 void *context)
+  SILC_LOG_DEBUG(("Injecting packet %p to stream %p", packet, packet->stream));
+
+  silc_mutex_lock(stream->lock);
+  if (!stream->destroyed)
+    silc_packet_dispatch(packet);
+  silc_mutex_unlock(stream->lock);
+  silc_packet_stream_unref(stream);
+}
+
+/* Write data to the stream.  Must be called with ps->lock locked.  Unlocks
+   the lock inside this function, unless no_unlock is TRUE.  Unlocks always
+   in case it returns FALSE. */
+
+static inline SilcBool silc_packet_stream_write(SilcPacketStream ps,
+                                               SilcBool no_unlock)
 {
-  SilcPacketStream ps = context;
-  int ret;
+  SilcStream stream;
+  SilcBool connected;
+  int i;
 
-  silc_mutex_lock(ps->lock);
+  if (ps->udp)
+    stream = ((SilcPacketStream)ps->stream)->stream;
+  else
+    stream = ps->stream;
+
+  if (ps->udp && silc_socket_stream_is_udp(stream, &connected)) {
+    if (!connected) {
+      /* Connectionless UDP stream */
+      while (silc_buffer_len(&ps->outbuf) > 0) {
+       i = silc_net_udp_send(stream, ps->remote_udp->remote_ip,
+                             ps->remote_udp->remote_port,
+                             ps->outbuf.data, silc_buffer_len(&ps->outbuf));
+       if (silc_unlikely(i == -2)) {
+         /* Error */
+         silc_buffer_reset(&ps->outbuf);
+         SILC_PACKET_CALLBACK_ERROR(ps, SILC_PACKET_ERR_WRITE);
+         return FALSE;
+       }
 
-  if (ps->destroyed) {
-    silc_mutex_unlock(ps->lock);
-    return;
+       if (silc_unlikely(i == -1)) {
+         /* Cannot write now, write later. */
+         if (!no_unlock)
+           silc_mutex_unlock(ps->lock);
+         return TRUE;
+       }
+
+       /* Wrote data */
+       silc_buffer_pull(&ps->outbuf, i);
+      }
+
+      silc_buffer_reset(&ps->outbuf);
+      if (!no_unlock)
+       silc_mutex_unlock(ps->lock);
+
+      return TRUE;
+    }
   }
 
-  switch (status) {
+  /* Write the data to the stream */
+  while (silc_buffer_len(&ps->outbuf) > 0) {
+    i = silc_stream_write(stream, ps->outbuf.data,
+                         silc_buffer_len(&ps->outbuf));
+    if (silc_unlikely(i == 0)) {
+      /* EOS */
+      silc_buffer_reset(&ps->outbuf);
+      silc_mutex_unlock(ps->lock);
+      SILC_PACKET_CALLBACK_EOS(ps);
+      return FALSE;
+    }
 
-  case SILC_STREAM_CAN_WRITE:
-    if (!silc_buffer_headlen(&ps->outbuf)) {
+    if (silc_unlikely(i == -2)) {
+      /* Error */
+      silc_buffer_reset(&ps->outbuf);
       silc_mutex_unlock(ps->lock);
-      return;
+      SILC_PACKET_CALLBACK_ERROR(ps, SILC_PACKET_ERR_WRITE);
+      return FALSE;
     }
 
-    SILC_LOG_DEBUG(("Writing pending data to stream"));
+    if (silc_unlikely(i == -1)) {
+      /* Cannot write now, write later. */
+      if (!no_unlock)
+       silc_mutex_unlock(ps->lock);
+      return TRUE;
+    }
 
-    /* Write pending data to stream */
-    while (silc_buffer_len(&ps->outbuf) > 0) {
-      ret = silc_stream_write(ps->stream, ps->outbuf.data,
-                             silc_buffer_len(&ps->outbuf));
-      if (ret == 0) {
-       /* EOS */
-       silc_buffer_reset(&ps->outbuf);
+    /* Wrote data */
+    silc_buffer_pull(&ps->outbuf, i);
+  }
+
+  silc_buffer_reset(&ps->outbuf);
+  if (!no_unlock)
+    silc_mutex_unlock(ps->lock);
+
+  return TRUE;
+}
+
+/* Reads data from stream.  Must be called with ps->lock locked.  If this
+   returns FALSE the lock has been unlocked.  If this returns packet stream
+   to `ret_ps' its lock has been acquired and `ps' lock has been unlocked.
+   It is returned if the stream is UDP and remote UDP stream exists for
+   the sender of the packet. */
+
+static inline SilcBool silc_packet_stream_read(SilcPacketStream ps,
+                                              SilcPacketStream *ret_ps)
+{
+  SilcStream stream;
+  SilcBuffer inbuf;
+  SilcBool connected;
+  int ret;
+
+  stream = ps->stream;
+  inbuf = &ps->sc->inbuf;
+
+  if (silc_socket_stream_is_udp(stream, &connected)) {
+    if (!connected) {
+      /* Connectionless UDP stream, read one UDP packet */
+      char remote_ip[64], tuple[64];
+      int remote_port;
+      SilcPacketStream remote;
+
+      ret = silc_net_udp_receive(stream, remote_ip, sizeof(remote_ip),
+                                &remote_port, inbuf->tail,
+                                silc_buffer_taillen(inbuf));
+
+      if (silc_unlikely(ret < 0)) {
        silc_mutex_unlock(ps->lock);
-       SILC_PACKET_CALLBACK_EOS(ps);
-       return;
-      }
+       if (ret == -1) {
+         /* Cannot read now, do it later. */
+         silc_buffer_pull(inbuf, silc_buffer_len(inbuf));
+         return FALSE;
+       }
 
-      if (ret == -2) {
        /* Error */
-       silc_buffer_reset(&ps->outbuf);
-       silc_mutex_unlock(ps->lock);
-       SILC_PACKET_CALLBACK_ERROR(ps, SILC_PACKET_ERR_WRITE);
-       return;
+       silc_buffer_reset(inbuf);
+       SILC_PACKET_CALLBACK_ERROR(ps, SILC_PACKET_ERR_READ);
+       return FALSE;
       }
 
-      if (ret == -1) {
-       /* Cannot write now, write later. */
+      /* See if remote packet stream exist for this sender */
+      silc_snprintf(tuple, sizeof(tuple), "%d%s", remote_port, remote_ip);
+      silc_mutex_lock(ps->sc->engine->lock);
+      if (silc_hash_table_find(ps->sc->engine->udp_remote, tuple, NULL,
+                              (void *)&remote)) {
+       silc_mutex_unlock(ps->sc->engine->lock);
+       SILC_LOG_DEBUG(("UDP packet from %s:%d for stream %p", remote_ip,
+                       remote_port, remote));
        silc_mutex_unlock(ps->lock);
-       return;
+       silc_mutex_lock(remote->lock);
+       *ret_ps = remote;
+       return TRUE;
+      }
+      silc_mutex_unlock(ps->sc->engine->lock);
+
+      /* Unknown sender */
+      if (!ps->remote_udp) {
+       ps->remote_udp = silc_calloc(1, sizeof(*ps->remote_udp));
+       if (silc_unlikely(!ps->remote_udp)) {
+         silc_mutex_unlock(ps->lock);
+         SILC_PACKET_CALLBACK_ERROR(ps, SILC_PACKET_ERR_NO_MEMORY);
+         return FALSE;
+       }
       }
 
-      /* Wrote data */
-      silc_buffer_pull(&ps->outbuf, ret);
-    }
+      /* Save sender IP and port */
+      silc_free(ps->remote_udp->remote_ip);
+      ps->remote_udp->remote_ip = strdup(remote_ip);
+      ps->remote_udp->remote_port = remote_port;
 
-    silc_buffer_reset(&ps->outbuf);
+      silc_buffer_pull_tail(inbuf, ret);
+      return TRUE;
+    }
+  }
 
+  /* Read data from the stream */
+  ret = silc_stream_read(stream, inbuf->tail, silc_buffer_taillen(inbuf));
+  if (silc_unlikely(ret <= 0)) {
     silc_mutex_unlock(ps->lock);
-    break;
+    if (ret == 0) {
+      /* EOS */
+      silc_buffer_reset(inbuf);
+      SILC_PACKET_CALLBACK_EOS(ps);
+      return FALSE;
+    }
 
-  case SILC_STREAM_CAN_READ:
-    /* Packet receiving can only happen in one thread for one SilcPacketStream,
-       so locking is not required in packet receiving procedure. */
+    if (ret == -1) {
+      /* Cannot read now, do it later. */
+      silc_buffer_pull(inbuf, silc_buffer_len(inbuf));
+      return FALSE;
+    }
+
+    /* Error */
+    silc_buffer_reset(inbuf);
+    SILC_PACKET_CALLBACK_ERROR(ps, SILC_PACKET_ERR_READ);
+    return FALSE;
+  }
+
+  silc_buffer_pull_tail(inbuf, ret);
+  return TRUE;
+}
+
+/* Our stream IO notifier callback. */
+
+static void silc_packet_stream_io(SilcStream stream, SilcStreamStatus status,
+                                 void *context)
+{
+  SilcPacketStream remote = NULL, ps = context;
+
+  silc_mutex_lock(ps->lock);
+
+  if (silc_unlikely(ps->destroyed)) {
     silc_mutex_unlock(ps->lock);
+    return;
+  }
 
+  switch (status) {
+  case SILC_STREAM_CAN_READ:
     SILC_LOG_DEBUG(("Reading data from stream"));
 
-    /* Make sure we have fair amount of free space in inbuf */
-    if (silc_buffer_taillen(&ps->inbuf) < SILC_PACKET_DEFAULT_SIZE)
-      if (!silc_buffer_realloc(&ps->inbuf, silc_buffer_truelen(&ps->inbuf) +
-                              SILC_PACKET_DEFAULT_SIZE * 2))
-       return;
-
     /* Read data from stream */
-    ret = silc_stream_read(ps->stream, ps->inbuf.tail,
-                          silc_buffer_taillen(&ps->inbuf));
-
-    if (ret == 0) {
-      /* EOS */
-      silc_buffer_reset(&ps->inbuf);
-      SILC_PACKET_CALLBACK_EOS(ps);
+    if (!silc_packet_stream_read(ps, &remote))
       return;
-    }
 
-    if (ret == -2) {
-      /* Error */
-      silc_buffer_reset(&ps->inbuf);
-      SILC_PACKET_CALLBACK_ERROR(ps, SILC_PACKET_ERR_READ);
-      return;
+    /* Now process the data */
+    silc_packet_stream_ref(ps);
+    if (!remote) {
+      silc_packet_read_process(ps);
+      silc_mutex_unlock(ps->lock);
+    } else {
+      silc_packet_read_process(remote);
+      silc_mutex_unlock(remote->lock);
     }
+    silc_packet_stream_unref(ps);
+    break;
 
-    if (ret == -1) {
-      /* Cannot read now, do it later. */
-      silc_buffer_pull(&ps->inbuf, silc_buffer_len(&ps->inbuf));
+  case SILC_STREAM_CAN_WRITE:
+    SILC_LOG_DEBUG(("Writing pending data to stream"));
+
+    if (silc_unlikely(!silc_buffer_headlen(&ps->outbuf))) {
+      silc_mutex_unlock(ps->lock);
       return;
     }
 
-    /* Read some data */
-    silc_buffer_pull_tail(&ps->inbuf, ret);
-
-    /* Now process the data */
-    silc_packet_read_process(ps);
-
+    /* Write pending data to stream */
+    silc_packet_stream_write(ps, FALSE);
     break;
 
   default:
@@ -280,13 +457,13 @@ static SilcPacket silc_packet_alloc(SilcPacketEngine engine)
     silc_mutex_unlock(engine->lock);
 
     packet = silc_calloc(1, sizeof(*packet));
-    if (!packet)
+    if (silc_unlikely(!packet))
       return NULL;
 
     SILC_LOG_DEBUG(("Allocating new packet %p", packet));
 
     tmp = silc_malloc(SILC_PACKET_DEFAULT_SIZE);
-    if (!tmp) {
+    if (silc_unlikely(!tmp)) {
       silc_free(packet);
       return NULL;
     }
@@ -306,6 +483,25 @@ static SilcPacket silc_packet_alloc(SilcPacketEngine engine)
   return packet;
 }
 
+/* UDP remote stream hash table destructor */
+
+static void silc_packet_engine_hash_destr(void *key, void *context,
+                                         void *user_context)
+{
+  silc_free(key);
+}
+
+/* Per scheduler context hash table destructor */
+
+static void silc_packet_engine_context_destr(void *key, void *context,
+                                            void *user_context)
+{
+  SilcPacketEngineContext sc = context;
+  silc_buffer_clear(&sc->inbuf);
+  silc_buffer_purge(&sc->inbuf);
+  silc_free(sc);
+}
+
 
 /******************************** Packet API ********************************/
 
@@ -332,6 +528,14 @@ silc_packet_engine_start(SilcRng rng, SilcBool router,
   if (!engine)
     return NULL;
 
+  engine->contexts = silc_hash_table_alloc(0, silc_hash_ptr, NULL, NULL, NULL,
+                                          silc_packet_engine_context_destr,
+                                          engine, TRUE);
+  if (!engine->contexts) {
+    silc_free(engine);
+    return NULL;
+  }
+
   engine->rng = rng;
   engine->local_is_router = router;
   engine->callbacks = callbacks;
@@ -343,12 +547,16 @@ silc_packet_engine_start(SilcRng rng, SilcBool router,
   silc_list_init(engine->packet_pool, struct SilcPacketStruct, next);
   for (i = 0; i < 5; i++) {
     packet = silc_calloc(1, sizeof(*packet));
-    if (!packet)
+    if (!packet) {
+      silc_packet_engine_stop(engine);
       return NULL;
+    }
 
     tmp = silc_malloc(SILC_PACKET_DEFAULT_SIZE);
-    if (!tmp)
+    if (!tmp) {
+      silc_packet_engine_stop(engine);
       return NULL;
+    }
     silc_buffer_set(&packet->buffer, tmp, SILC_PACKET_DEFAULT_SIZE);
     silc_buffer_reset(&packet->buffer);
 
@@ -392,35 +600,165 @@ SilcPacketStream silc_packet_stream_create(SilcPacketEngine engine,
   if (!ps)
     return NULL;
 
-  ps->engine = engine;
   ps->stream = stream;
-  ps->refcnt++;
+  silc_atomic_init8(&ps->refcnt, 1);
+  silc_mutex_alloc(&ps->lock);
 
-  /* Allocate buffers */
-  tmp = silc_malloc(SILC_PACKET_DEFAULT_SIZE);
-  if (!tmp)
-    return NULL;
-  silc_buffer_set(&ps->inbuf, tmp, SILC_PACKET_DEFAULT_SIZE);
-  silc_buffer_reset(&ps->inbuf);
+  /* Allocate out buffer */
   tmp = silc_malloc(SILC_PACKET_DEFAULT_SIZE);
-  if (!tmp)
+  if (!tmp) {
+    silc_packet_stream_destroy(ps);
     return NULL;
+  }
   silc_buffer_set(&ps->outbuf, tmp, SILC_PACKET_DEFAULT_SIZE);
   silc_buffer_reset(&ps->outbuf);
 
   /* Initialize packet procesors list */
   ps->process = silc_dlist_init();
+  if (!ps->process) {
+    silc_packet_stream_destroy(ps);
+    return NULL;
+  }
 
-  /* Set IO notifier callback */
+  silc_mutex_lock(engine->lock);
+
+  /* Add per scheduler context */
+  if (!silc_hash_table_find(engine->contexts, schedule, NULL,
+                           (void *)&ps->sc)) {
+    ps->sc = silc_calloc(1, sizeof(*ps->sc));
+    if (!ps->sc) {
+      silc_packet_stream_destroy(ps);
+      silc_mutex_unlock(engine->lock);
+      return NULL;
+    }
+    ps->sc->engine = engine;
+    ps->sc->schedule = schedule;
+
+    /* Allocate data input buffer */
+    tmp = silc_malloc(SILC_PACKET_DEFAULT_SIZE * 31);
+    if (!tmp) {
+      silc_free(ps->sc);
+      ps->sc = NULL;
+      silc_packet_stream_destroy(ps);
+      silc_mutex_unlock(engine->lock);
+      return NULL;
+    }
+    silc_buffer_set(&ps->sc->inbuf, tmp, SILC_PACKET_DEFAULT_SIZE * 31);
+    silc_buffer_reset(&ps->sc->inbuf);
+
+    /* Add to per scheduler context hash table */
+    if (!silc_hash_table_add(engine->contexts, schedule, ps->sc)) {
+      silc_buffer_purge(&ps->sc->inbuf);
+      silc_free(ps->sc);
+      ps->sc = NULL;
+      silc_packet_stream_destroy(ps);
+      silc_mutex_unlock(engine->lock);
+      return NULL;
+    }
+  }
+  ps->sc->stream_count++;
+
+  /* Add the packet stream to engine */
+  silc_list_add(engine->streams, ps);
+
+  /* If this is UDP stream, allocate UDP remote stream hash table */
+  if (!engine->udp_remote && silc_socket_stream_is_udp(stream, NULL))
+    engine->udp_remote = silc_hash_table_alloc(0, silc_hash_string, NULL,
+                                              silc_hash_string_compare, NULL,
+                                              silc_packet_engine_hash_destr,
+                                              NULL, TRUE);
+  silc_mutex_unlock(engine->lock);
+
+  /* Set IO notifier callback.  This schedules this stream for I/O. */
   silc_stream_set_notifier(ps->stream, schedule, silc_packet_stream_io, ps);
 
+  return ps;
+}
+
+/* Add new remote packet stream for UDP packet streams */
+
+SilcPacketStream silc_packet_stream_add_remote(SilcPacketStream stream,
+                                              const char *remote_ip,
+                                              SilcUInt16 remote_port,
+                                              SilcPacket packet)
+{
+  SilcPacketEngine engine = stream->sc->engine;
+  SilcPacketStream ps;
+  char *tuple;
+  void *tmp;
+
+  SILC_LOG_DEBUG(("Adding UDP remote %s:%d to packet stream %p",
+                 remote_ip, remote_port, stream));
+
+  if (!stream || !remote_ip || !remote_port)
+    return NULL;
+
+  if (!silc_socket_stream_is_udp(stream->stream, NULL)) {
+    SILC_LOG_ERROR(("Stream is not UDP stream, cannot add remote IP"));
+    return NULL;
+  }
+
+  ps = silc_calloc(1, sizeof(*ps));
+  if (!ps)
+    return NULL;
+  ps->sc = stream->sc;
+
+  silc_atomic_init8(&ps->refcnt, 1);
   silc_mutex_alloc(&ps->lock);
 
-  /* Add to engine */
+  /* Set the UDP packet stream as underlaying stream */
+  silc_packet_stream_ref(stream);
+  ps->stream = (SilcStream)stream;
+  ps->udp = TRUE;
+
+  /* Allocate out buffer */
+  tmp = silc_malloc(SILC_PACKET_DEFAULT_SIZE);
+  if (!tmp) {
+    silc_packet_stream_destroy(ps);
+    return NULL;
+  }
+  silc_buffer_set(&ps->outbuf, tmp, SILC_PACKET_DEFAULT_SIZE);
+  silc_buffer_reset(&ps->outbuf);
+
+  /* Initialize packet procesors list */
+  ps->process = silc_dlist_init();
+  if (!ps->process) {
+    silc_packet_stream_destroy(ps);
+    return NULL;
+  }
+
+  /* Add to engine with this IP and port pair */
+  tuple = silc_format("%d%s", remote_port, remote_ip);
   silc_mutex_lock(engine->lock);
-  silc_list_add(engine->streams, ps);
+  if (!tuple || !silc_hash_table_add(engine->udp_remote, tuple, ps)) {
+    silc_mutex_unlock(engine->lock);
+    silc_packet_stream_destroy(ps);
+    return NULL;
+  }
   silc_mutex_unlock(engine->lock);
 
+  /* Save remote IP and port pair */
+  ps->remote_udp = silc_calloc(1, sizeof(*ps->remote_udp));
+  if (!ps->remote_udp) {
+    silc_packet_stream_destroy(ps);
+    return NULL;
+  }
+  ps->remote_udp->remote_port = remote_port;
+  ps->remote_udp->remote_ip = strdup(remote_ip);
+  if (!ps->remote_udp->remote_ip) {
+    silc_packet_stream_destroy(ps);
+    return NULL;
+  }
+
+  if (packet) {
+    /* Inject packet to the new stream */
+    packet->stream = ps;
+    silc_packet_stream_ref(ps);
+    silc_schedule_task_add_timeout(silc_stream_get_schedule(stream->stream),
+                                  silc_packet_stream_inject_packet, packet,
+                                  0, 0);
+  }
+
   return ps;
 }
 
@@ -431,28 +769,65 @@ void silc_packet_stream_destroy(SilcPacketStream stream)
   if (!stream)
     return;
 
-  if (stream->refcnt > 1) {
+  if (silc_atomic_get_int8(&stream->refcnt) > 1) {
     stream->destroyed = TRUE;
     return;
   }
 
   SILC_LOG_DEBUG(("Destroying packet stream %p", stream));
 
-  /* Delete from engine */
-  silc_mutex_lock(stream->engine->lock);
-  silc_list_del(stream->engine->streams, stream);
-  silc_mutex_unlock(stream->engine->lock);
+  if (!stream->udp) {
+    /* Delete from engine */
+    silc_mutex_lock(stream->sc->engine->lock);
+    silc_list_del(stream->sc->engine->streams, stream);
+
+    /* Remove per scheduler context, if it is not used anymore */
+    if (stream->sc) {
+      stream->sc->stream_count--;
+      if (!stream->sc->stream_count)
+       silc_hash_table_del(stream->sc->engine->contexts,
+                           stream->sc->schedule);
+    }
+    silc_mutex_unlock(stream->sc->engine->lock);
+
+    /* Destroy the underlaying stream */
+    if (stream->stream)
+      silc_stream_destroy(stream->stream);
+  } else {
+    /* Delete from UDP remote hash table */
+    char tuple[64];
+    silc_snprintf(tuple, sizeof(tuple), "%d%s", stream->remote_udp->remote_port,
+            stream->remote_udp->remote_ip);
+    silc_mutex_lock(stream->sc->engine->lock);
+    silc_hash_table_del(stream->sc->engine->udp_remote, tuple);
+    silc_mutex_unlock(stream->sc->engine->lock);
+
+    silc_free(stream->remote_udp->remote_ip);
+    silc_free(stream->remote_udp);
+
+    /* Unreference the underlaying packet stream */
+    silc_packet_stream_unref((SilcPacketStream)stream->stream);
+  }
 
   /* Clear and free buffers */
-  silc_buffer_clear(&stream->inbuf);
   silc_buffer_clear(&stream->outbuf);
-  silc_free(silc_buffer_steal(&stream->inbuf, NULL));
-  silc_free(silc_buffer_steal(&stream->outbuf, NULL));
+  silc_buffer_purge(&stream->outbuf);
 
-  silc_dlist_uninit(stream->process);
+  if (stream->process) {
+    SilcPacketProcess p;
+    silc_dlist_start(stream->process);
+    while ((p = silc_dlist_get(stream->process))) {
+      silc_free(p->types);
+      silc_free(p);
+      silc_dlist_del(stream->process, p);
+    }
+    silc_dlist_uninit(stream->process);
+  }
 
   /* XXX */
 
+  silc_atomic_uninit8(&stream->refcnt);
+  silc_mutex_free(stream->lock);
   silc_free(stream);
 }
 
@@ -463,6 +838,12 @@ void silc_packet_stream_set_router(SilcPacketStream stream)
   stream->is_router = TRUE;
 }
 
+/* Mark to include IV in ciphertext */
+
+void silc_packet_stream_set_iv_included(SilcPacketStream stream)
+{
+  stream->iv_included = TRUE;
+}
 
 /* Links `callbacks' to `stream' for specified packet types */
 
@@ -494,8 +875,10 @@ static SilcBool silc_packet_stream_link_va(SilcPacketStream stream,
 
   if (!stream->process) {
     stream->process = silc_dlist_init();
-    if (!stream->process)
+    if (!stream->process) {
+      silc_mutex_unlock(stream->lock);
       return FALSE;
+    }
   }
 
   /* According to priority set the procesor to correct position.  First
@@ -576,6 +959,7 @@ void silc_packet_stream_unlink(SilcPacketStream stream,
     if (p->callbacks == callbacks &&
        p->callback_context == callback_context) {
       silc_dlist_del(stream->process, p);
+      silc_free(p->types);
       silc_free(p);
       break;
     }
@@ -590,23 +974,40 @@ void silc_packet_stream_unlink(SilcPacketStream stream,
   silc_packet_stream_unref(stream);
 }
 
+/* Returns TRUE if stream is UDP stream */
+
+SilcBool silc_packet_stream_is_udp(SilcPacketStream stream)
+{
+  return stream->udp || silc_socket_stream_is_udp(stream->stream, NULL);
+}
+
+/* Return packet sender IP and port for UDP packet stream */
+
+SilcBool silc_packet_get_sender(SilcPacket packet,
+                               const char **sender_ip,
+                               SilcUInt16 *sender_port)
+{
+  if (!packet->stream->remote_udp)
+    return FALSE;
+
+  *sender_ip = packet->stream->remote_udp->remote_ip;
+  *sender_port = packet->stream->remote_udp->remote_port;
+
+  return TRUE;
+}
+
 /* Reference packet stream */
 
 void silc_packet_stream_ref(SilcPacketStream stream)
 {
-  silc_mutex_lock(stream->lock);
-  stream->refcnt++;
-  silc_mutex_unlock(stream->lock);
+  silc_atomic_add_int8(&stream->refcnt, 1);
 }
 
 /* Unreference packet stream */
 
 void silc_packet_stream_unref(SilcPacketStream stream)
 {
-  silc_mutex_lock(stream->lock);
-  stream->refcnt--;
-  silc_mutex_unlock(stream->lock);
-  if (stream->refcnt == 0)
+  if (silc_atomic_sub_int8(&stream->refcnt, 1) == 0)
     silc_packet_stream_destroy(stream);
 }
 
@@ -614,21 +1015,39 @@ void silc_packet_stream_unref(SilcPacketStream stream)
 
 SilcPacketEngine silc_packet_get_engine(SilcPacketStream stream)
 {
-  return stream->engine;
+  return stream->sc->engine;
 }
 
 /* Set application context for packet stream */
 
 void silc_packet_set_context(SilcPacketStream stream, void *stream_context)
 {
+  silc_mutex_lock(stream->lock);
   stream->stream_context = stream_context;
+  silc_mutex_unlock(stream->lock);
 }
 
 /* Return application context from packet stream */
 
 void *silc_packet_get_context(SilcPacketStream stream)
 {
-  return stream->stream_context;
+  void *context;
+  silc_mutex_lock(stream->lock);
+  context = stream->stream_context;
+  silc_mutex_unlock(stream->lock);
+  return context;
+}
+
+/* Change underlaying stream */
+
+void silc_packet_stream_set_stream(SilcPacketStream ps,
+                                  SilcStream stream)
+{
+  if (ps->stream)
+    silc_stream_set_notifier(ps->stream, ps->sc->schedule, NULL, NULL);
+  ps->stream = stream;
+  silc_stream_set_notifier(ps->stream, ps->sc->schedule, silc_packet_stream_io,
+                          ps);
 }
 
 /* Return underlaying stream */
@@ -638,54 +1057,99 @@ SilcStream silc_packet_stream_get_stream(SilcPacketStream stream)
   return stream->stream;
 }
 
-/* Set ciphers for packet stream */
+/* Set keys. */
 
-void silc_packet_set_ciphers(SilcPacketStream stream, SilcCipher send,
-                            SilcCipher receive)
+SilcBool silc_packet_set_keys(SilcPacketStream stream, SilcCipher send_key,
+                              SilcCipher receive_key, SilcHmac send_hmac,
+                              SilcHmac receive_hmac, SilcBool rekey)
 {
-  SILC_LOG_DEBUG(("Setting new ciphers to packet stream"));
-  stream->send_key = send;
-  stream->receive_key = receive;
-}
+  SILC_LOG_DEBUG(("Setting new keys to packet stream %p", stream));
+
+  /* If doing rekey, send REKEY_DONE packet */
+  if (rekey) {
+    /* This will take stream lock. */
+    if (!silc_packet_send_raw(stream, SILC_PACKET_REKEY_DONE, 0,
+                             stream->src_id_type, stream->src_id,
+                             stream->src_id_len, stream->dst_id_type,
+                             stream->dst_id, stream->dst_id_len,
+                             NULL, 0, stream->send_key[0],
+                             stream->send_hmac[0]))
+      return FALSE;
 
-/* Return current ciphers from packet stream */
+    /* Write the packet to the stream */
+    if (!silc_packet_stream_write(stream, TRUE))
+      return FALSE;
+  } else {
+    silc_mutex_lock(stream->lock);
+  }
 
-SilcBool silc_packet_get_ciphers(SilcPacketStream stream, SilcCipher *send,
-                                SilcCipher *receive)
-{
-  if (!stream->send_key && !stream->receive_key)
-    return FALSE;
+  /* In case IV Included is set, save the old keys */
+  if (stream->iv_included) {
+    if (stream->send_key[1] && send_key) {
+      silc_cipher_free(stream->send_key[1]);
+      stream->send_key[1] = stream->send_key[0];
+    }
+    if (stream->receive_key[1] && receive_key) {
+      silc_cipher_free(stream->receive_key[1]);
+      stream->receive_key[1] = stream->receive_key[0];
+    }
+    if (stream->send_hmac[1] && send_hmac) {
+      silc_hmac_free(stream->send_hmac[1]);
+      stream->send_hmac[1] = stream->send_hmac[0];
+    }
+    if (stream->receive_hmac[1] && receive_hmac) {
+      silc_hmac_free(stream->receive_hmac[1]);
+      stream->receive_hmac[1] = stream->receive_hmac[0];
+    }
+  } else {
+    if (stream->send_key[0] && send_key)
+      silc_cipher_free(stream->send_key[0]);
+    if (stream->send_key[1] && receive_key)
+      silc_cipher_free(stream->receive_key[0]);
+    if (stream->send_hmac[0] && send_hmac)
+      silc_hmac_free(stream->send_hmac[0]);
+    if (stream->receive_hmac[0] && receive_hmac)
+      silc_hmac_free(stream->receive_hmac[0]);
+  }
 
-  if (send)
-    *send = stream->send_key;
-  if (receive)
-    *receive = stream->receive_key;
+  /* Set keys */
+  if (send_key)
+    stream->send_key[0] = send_key;
+  if (receive_key)
+    stream->receive_key[0] = receive_key;
+  if (send_hmac)
+    stream->send_hmac[0] = send_hmac;
+  if (receive_hmac)
+    stream->receive_hmac[0] = receive_hmac;
 
+  silc_mutex_unlock(stream->lock);
   return TRUE;
 }
 
-/* Set HMACs for packet stream */
+/* Return current ciphers from packet stream */
 
-void silc_packet_set_hmacs(SilcPacketStream stream, SilcHmac send,
-                          SilcHmac receive)
+SilcBool silc_packet_get_keys(SilcPacketStream stream,
+                             SilcCipher *send_key,
+                             SilcCipher *receive_key,
+                             SilcHmac *send_hmac,
+                             SilcHmac *receive_hmac)
 {
-  SILC_LOG_DEBUG(("Setting new HMACs to packet stream"));
-  stream->send_hmac = send;
-  stream->receive_hmac = receive;
-}
+  if (!stream->send_key[0] && !stream->receive_key[0] &&
+      !stream->send_hmac[0] && !stream->receive_hmac[0])
+    return FALSE;
 
-/* Return current HMACs from packet stream */
+  silc_mutex_lock(stream->lock);
 
-SilcBool silc_packet_get_hmacs(SilcPacketStream stream, SilcHmac *send,
-                              SilcHmac *receive)
-{
-  if (!stream->send_hmac && !stream->receive_hmac)
-    return FALSE;
+  if (send_key)
+    *send_key = stream->send_key[0];
+  if (receive_key)
+    *receive_key = stream->receive_key[0];
+  if (send_hmac)
+    *send_hmac = stream->send_hmac[0];
+  if (receive_hmac)
+    *receive_hmac = stream->receive_hmac[0];
 
-  if (send)
-    *send = stream->send_hmac;
-  if (receive)
-    *receive = stream->receive_hmac;
+  silc_mutex_unlock(stream->lock);
 
   return TRUE;
 }
@@ -704,28 +1168,53 @@ SilcBool silc_packet_set_ids(SilcPacketStream stream,
 
   SILC_LOG_DEBUG(("Setting new IDs to packet stream"));
 
+  silc_mutex_lock(stream->lock);
+
   if (src_id) {
     silc_free(stream->src_id);
-    if (!silc_id_id2str(src_id, src_id_type, tmp, sizeof(tmp), &len))
+    if (!silc_id_id2str(src_id, src_id_type, tmp, sizeof(tmp), &len)) {
+      silc_mutex_unlock(stream->lock);
       return FALSE;
+    }
     stream->src_id = silc_memdup(tmp, len);
-    if (!stream->src_id)
+    if (!stream->src_id) {
+      silc_mutex_unlock(stream->lock);
       return FALSE;
+    }
     stream->src_id_type = src_id_type;
     stream->src_id_len = len;
   }
 
   if (dst_id) {
     silc_free(stream->dst_id);
-    if (!silc_id_id2str(dst_id, dst_id_type, tmp, sizeof(tmp), &len))
+    if (!silc_id_id2str(dst_id, dst_id_type, tmp, sizeof(tmp), &len)) {
+      silc_mutex_unlock(stream->lock);
       return FALSE;
+    }
     stream->dst_id = silc_memdup(tmp, len);
-    if (!stream->dst_id)
+    if (!stream->dst_id) {
+      silc_mutex_unlock(stream->lock);
       return FALSE;
+    }
     stream->dst_id_type = dst_id_type;
     stream->dst_id_len = len;
   }
 
+  silc_mutex_unlock(stream->lock);
+
+  return TRUE;
+}
+
+/* Adds Security ID (SID) */
+
+SilcBool silc_packet_set_sid(SilcPacketStream stream, SilcUInt8 sid)
+{
+  if (!stream->iv_included)
+    return FALSE;
+
+  SILC_LOG_DEBUG(("Set packet stream %p SID to %d", stream, sid));
+
+  stream->sid = sid;
   return TRUE;
 }
 
@@ -737,50 +1226,32 @@ void silc_packet_free(SilcPacket packet)
 
   SILC_LOG_DEBUG(("Freeing packet %p", packet));
 
-#if defined(SILC_DEBUG)
   /* Check for double free */
-  assert(packet->stream != NULL);
-#endif /* SILC_DEBUG */
-
-  silc_mutex_lock(stream->engine->lock);
+  SILC_ASSERT(packet->stream != NULL);
 
   packet->stream = NULL;
   packet->src_id = packet->dst_id = NULL;
   silc_buffer_reset(&packet->buffer);
 
-  /* Put the packet back to freelist */
-  silc_list_add(stream->engine->packet_pool, packet);
+  silc_mutex_lock(stream->sc->engine->lock);
 
-  silc_mutex_unlock(stream->engine->lock);
-}
-
-/* Creates streamer */
-
-SilcStream silc_packet_streamer_create(SilcPacketStream stream,
-                                      SilcPacketType packet_type,
-                                      SilcPacketFlags packet_flags)
-{
-  /* XXX TODO */
-  return NULL;
-}
-
-/* Destroyes streamer */
-
-void silc_packet_streamer_destroy(SilcStream stream)
-{
+  /* Put the packet back to freelist */
+  silc_list_add(stream->sc->engine->packet_pool, packet);
+  if (silc_list_count(stream->sc->engine->packet_pool) == 1)
+    silc_list_start(stream->sc->engine->packet_pool);
 
+  silc_mutex_unlock(stream->sc->engine->lock);
 }
 
-
 /****************************** Packet Sending ******************************/
 
 /* Prepare outgoing data buffer for packet sending.  Returns the
    pointer to that buffer into the `packet'. */
 
-static SilcBool silc_packet_send_prepare(SilcPacketStream stream,
-                                        SilcUInt32 totlen,
-                                        SilcHmac hmac,
-                                        SilcBuffer packet)
+static inline SilcBool silc_packet_send_prepare(SilcPacketStream stream,
+                                               SilcUInt32 totlen,
+                                               SilcHmac hmac,
+                                               SilcBuffer packet)
 {
   unsigned char *oldptr;
   unsigned int mac_len = hmac ? silc_hmac_len(hmac) : 0;
@@ -788,7 +1259,7 @@ static SilcBool silc_packet_send_prepare(SilcPacketStream stream,
   totlen += mac_len;
 
   /* Allocate more space if needed */
-  if (silc_buffer_taillen(&stream->outbuf) < totlen) {
+  if (silc_unlikely(silc_buffer_taillen(&stream->outbuf) < totlen)) {
     if (!silc_buffer_realloc(&stream->outbuf,
                             silc_buffer_truelen(&stream->outbuf) + totlen))
       return FALSE;
@@ -804,28 +1275,65 @@ static SilcBool silc_packet_send_prepare(SilcPacketStream stream,
   return TRUE;
 }
 
-/* Internal routine to send packet */
-
-static SilcBool silc_packet_send_raw(SilcPacketStream stream,
-                                    SilcPacketType type,
-                                    SilcPacketFlags flags,
-                                    SilcIdType src_id_type,
-                                    unsigned char *src_id,
-                                    SilcUInt32 src_id_len,
-                                    SilcIdType dst_id_type,
-                                    unsigned char *dst_id,
-                                    SilcUInt32 dst_id_len,
-                                    const unsigned char *data,
-                                    SilcUInt32 data_len,
-                                    SilcCipher cipher,
-                                    SilcHmac hmac)
+/* Increments counter when encrypting in counter mode. */
+
+static inline void silc_packet_send_ctr_increment(SilcPacketStream stream,
+                                                 SilcCipher cipher,
+                                                 unsigned char *ret_iv)
 {
-  unsigned char tmppad[SILC_PACKET_MAX_PADLEN];
+  unsigned char *iv = silc_cipher_get_iv(cipher);
+  SilcUInt32 pc;
+
+  /* Increment packet counter */
+  SILC_GET32_MSB(pc, iv + 8);
+  pc++;
+  SILC_PUT32_MSB(pc, iv + 8);
+
+  /* Reset block counter */
+  memset(iv + 12, 0, 4);
+
+  /* If IV Included flag, return the 64-bit IV for inclusion in packet */
+  if (stream->iv_included) {
+    /* Get new nonce */
+    ret_iv[0] = silc_rng_get_byte_fast(stream->sc->engine->rng);
+    ret_iv[1] = ret_iv[0] + iv[4];
+    ret_iv[2] = ret_iv[0] ^ ret_iv[1];
+    ret_iv[3] = ret_iv[0] + ret_iv[2];
+    SILC_PUT32_MSB(pc, ret_iv + 4);
+    SILC_LOG_HEXDUMP(("IV"), ret_iv, 8);
+
+    /* Set new nonce to counter block */
+    memcpy(iv + 4, ret_iv, 4);
+  }
+
+  SILC_LOG_HEXDUMP(("Counter Block"), iv, 16);
+}
+
+/* Internal routine to assemble outgoing packet.  Assembles and encryptes
+   the packet.  The silc_packet_stream_write needs to be called to send it
+   after this returns TRUE. */
+
+static inline SilcBool silc_packet_send_raw(SilcPacketStream stream,
+                                           SilcPacketType type,
+                                           SilcPacketFlags flags,
+                                           SilcIdType src_id_type,
+                                           unsigned char *src_id,
+                                           SilcUInt32 src_id_len,
+                                           SilcIdType dst_id_type,
+                                           unsigned char *dst_id,
+                                           SilcUInt32 dst_id_len,
+                                           const unsigned char *data,
+                                           SilcUInt32 data_len,
+                                           SilcCipher cipher,
+                                           SilcHmac hmac)
+{
+  unsigned char tmppad[SILC_PACKET_MAX_PADLEN], iv[33], psn[4];
   int block_len = (cipher ? silc_cipher_get_block_len(cipher) : 0);
-  int i, enclen, truelen, padlen;
+  int i, enclen, truelen, padlen = 0, ivlen = 0, psnlen = 0;
+  SilcBool ctr;
   SilcBufferStruct packet;
 
-  SILC_LOG_DEBUG(("Sending packet %s (%d) flags %d, src %d dst %d,"
+  SILC_LOG_DEBUG(("Sending packet %s (%d) flags %d, src %d dst %d, "
                  "data len %d", silc_get_packet_name(type), stream->send_psn,
                  flags, src_id_type, dst_id_type, data_len));
 
@@ -837,6 +1345,27 @@ static SilcBool silc_packet_send_raw(SilcPacketStream stream,
   enclen = truelen = (data_len + SILC_PACKET_HEADER_LEN +
                      src_id_len + dst_id_len);
 
+  /* If using CTR mode, increment the counter */
+  ctr = (cipher && silc_cipher_get_mode(cipher) == SILC_CIPHER_MODE_CTR);
+  if (ctr) {
+    silc_packet_send_ctr_increment(stream, cipher, iv + 1);
+
+    /* If IV is included, the SID, IV and sequence number is added to packet */
+    if (stream->iv_included && cipher) {
+      psnlen = sizeof(psn);
+      ivlen = 8 + 1;
+      iv[0] = stream->sid;
+    }
+  } else {
+    /* If IV is included, the SID, IV and sequence number is added to packet */
+    if (stream->iv_included && cipher) {
+      psnlen = sizeof(psn);
+      ivlen = block_len + 1;
+      iv[0] = stream->sid;
+      memcpy(iv + 1, silc_cipher_get_iv(cipher), block_len);
+    }
+  }
+
   /* We automatically figure out the packet structure from the packet
      type and flags, and calculate correct length.  Private messages with
      private keys and channel messages are special packets as their
@@ -846,21 +1375,22 @@ static SilcBool silc_packet_send_raw(SilcPacketStream stream,
       type == SILC_PACKET_CHANNEL_MESSAGE) {
 
     /* Padding is calculated from header + IDs */
-    SILC_PACKET_PADLEN((SILC_PACKET_HEADER_LEN +
-                       src_id_len +
-                       dst_id_len), block_len, padlen);
+    if (!ctr)
+      SILC_PACKET_PADLEN((SILC_PACKET_HEADER_LEN + src_id_len + dst_id_len +
+                         psnlen), block_len, padlen);
 
     /* Length to encrypt, header + IDs + padding. */
-    enclen = SILC_PACKET_HEADER_LEN + src_id_len + dst_id_len + padlen;
+    enclen = (SILC_PACKET_HEADER_LEN + src_id_len + dst_id_len +
+             padlen + psnlen);
   } else {
 
     /* Padding is calculated from true length of the packet */
     if (flags & SILC_PACKET_FLAG_LONG_PAD)
-      SILC_PACKET_PADLEN_MAX(truelen, block_len, padlen);
-    else
-      SILC_PACKET_PADLEN(truelen, block_len, padlen);
+      SILC_PACKET_PADLEN_MAX(truelen + psnlen, block_len, padlen);
+    else if (!ctr)
+      SILC_PACKET_PADLEN(truelen + psnlen, block_len, padlen);
 
-    enclen += padlen;
+    enclen += padlen + psnlen;
   }
 
   /* Remove implementation specific flags */
@@ -868,19 +1398,24 @@ static SilcBool silc_packet_send_raw(SilcPacketStream stream,
 
   /* Get random padding */
   for (i = 0; i < padlen; i++) tmppad[i] =
-                                silc_rng_get_byte_fast(stream->engine->rng);
+    silc_rng_get_byte_fast(stream->sc->engine->rng);
 
   silc_mutex_lock(stream->lock);
 
   /* Get packet pointer from the outgoing buffer */
-  if (!silc_packet_send_prepare(stream, truelen + padlen, hmac, &packet)) {
+  if (silc_unlikely(!silc_packet_send_prepare(stream, truelen + padlen + ivlen
+                                             + psnlen, hmac, &packet))) {
     silc_mutex_unlock(stream->lock);
     return FALSE;
   }
 
+  SILC_PUT32_MSB(stream->send_psn, psn);
+
   /* Create the packet.  This creates the SILC header, adds padding, and
      the actual packet data. */
   i = silc_buffer_format(&packet,
+                        SILC_STR_DATA(iv, ivlen),
+                        SILC_STR_DATA(psn, psnlen),
                         SILC_STR_UI_SHORT(truelen),
                         SILC_STR_UI_CHAR(flags),
                         SILC_STR_UI_CHAR(type),
@@ -889,25 +1424,26 @@ static SilcBool silc_packet_send_raw(SilcPacketStream stream,
                         SILC_STR_UI_CHAR(src_id_len),
                         SILC_STR_UI_CHAR(dst_id_len),
                         SILC_STR_UI_CHAR(src_id_type),
-                        SILC_STR_UI_XNSTRING(src_id, src_id_len),
+                        SILC_STR_DATA(src_id, src_id_len),
                         SILC_STR_UI_CHAR(dst_id_type),
-                        SILC_STR_UI_XNSTRING(dst_id, dst_id_len),
-                        SILC_STR_UI_XNSTRING(tmppad, padlen),
-                        SILC_STR_UI_XNSTRING(data, data_len),
+                        SILC_STR_DATA(dst_id, dst_id_len),
+                        SILC_STR_DATA(tmppad, padlen),
+                        SILC_STR_DATA(data, data_len),
                         SILC_STR_END);
-  if (i < 0) {
+  if (silc_unlikely(i < 0)) {
     silc_mutex_unlock(stream->lock);
     return FALSE;
   }
 
   SILC_LOG_HEXDUMP(("Assembled packet, len %d", silc_buffer_len(&packet)),
-                  packet.data, silc_buffer_len(&packet));
+                  silc_buffer_data(&packet), silc_buffer_len(&packet));
 
   /* Encrypt the packet */
-  if (cipher) {
+  if (silc_likely(cipher)) {
     SILC_LOG_DEBUG(("Encrypting packet"));
-    if (!silc_cipher_encrypt(cipher, packet.data, packet.data,
-                            enclen, NULL)) {
+    if (silc_unlikely(!silc_cipher_encrypt(cipher, packet.data + ivlen,
+                                          packet.data + ivlen, enclen,
+                                          NULL))) {
       SILC_LOG_ERROR(("Packet encryption failed"));
       silc_mutex_unlock(stream->lock);
       return FALSE;
@@ -915,53 +1451,19 @@ static SilcBool silc_packet_send_raw(SilcPacketStream stream,
   }
 
   /* Compute HMAC */
-  if (hmac) {
-    unsigned char psn[4];
+  if (silc_likely(hmac)) {
     SilcUInt32 mac_len;
 
     /* MAC is computed from the entire encrypted packet data, and put
        to the end of the packet. */
     silc_hmac_init(hmac);
-    SILC_PUT32_MSB(stream->send_psn, psn);
-    silc_hmac_update(hmac, psn, 4);
+    silc_hmac_update(hmac, psn, sizeof(psn));
     silc_hmac_update(hmac, packet.data, silc_buffer_len(&packet));
     silc_hmac_final(hmac, packet.tail, &mac_len);
     silc_buffer_pull_tail(&packet, mac_len);
     stream->send_psn++;
   }
 
-  /* Write the packet to the stream */
-  while (silc_buffer_len(&stream->outbuf) > 0) {
-    i = silc_stream_write(stream->stream, stream->outbuf.data,
-                         silc_buffer_len(&stream->outbuf));
-    if (i == 0) {
-      /* EOS */
-      silc_buffer_reset(&stream->outbuf);
-      silc_mutex_unlock(stream->lock);
-      SILC_PACKET_CALLBACK_EOS(stream);
-      return FALSE;
-    }
-
-    if (i == -2) {
-      /* Error */
-      silc_buffer_reset(&stream->outbuf);
-      silc_mutex_unlock(stream->lock);
-      SILC_PACKET_CALLBACK_ERROR(stream, SILC_PACKET_ERR_WRITE);
-      return FALSE;
-    }
-
-    if (i == -1) {
-      /* Cannot write now, write later. */
-      silc_mutex_unlock(stream->lock);
-      return TRUE;
-    }
-
-    /* Wrote data */
-    silc_buffer_pull(&stream->outbuf, i);
-  }
-  silc_buffer_reset(&stream->outbuf);
-
-  silc_mutex_unlock(stream->lock);
   return TRUE;
 }
 
@@ -971,16 +1473,21 @@ SilcBool silc_packet_send(SilcPacketStream stream,
                          SilcPacketType type, SilcPacketFlags flags,
                          const unsigned char *data, SilcUInt32 data_len)
 {
-  return silc_packet_send_raw(stream, type, flags,
-                             stream->src_id_type,
-                             stream->src_id,
-                             stream->src_id_len,
-                             stream->dst_id_type,
-                             stream->dst_id,
-                             stream->dst_id_len,
-                             data, data_len,
-                             stream->send_key,
-                             stream->send_hmac);
+  SilcBool ret;
+
+  ret = silc_packet_send_raw(stream, type, flags,
+                            stream->src_id_type,
+                            stream->src_id,
+                            stream->src_id_len,
+                            stream->dst_id_type,
+                            stream->dst_id,
+                            stream->dst_id_len,
+                            data, data_len,
+                            stream->send_key[0],
+                            stream->send_hmac[0]);
+
+  /* Write the packet to the stream */
+  return ret ? silc_packet_stream_write(stream, FALSE) : FALSE;
 }
 
 /* Sends a packet, extended routine */
@@ -994,6 +1501,7 @@ SilcBool silc_packet_send_ext(SilcPacketStream stream,
 {
   unsigned char src_id_data[32], dst_id_data[32];
   SilcUInt32 src_id_len, dst_id_len;
+  SilcBool ret;
 
   if (src_id)
     if (!silc_id_id2str(src_id, src_id_type, src_id_data,
@@ -1004,31 +1512,90 @@ SilcBool silc_packet_send_ext(SilcPacketStream stream,
                        sizeof(dst_id_data), &dst_id_len))
       return FALSE;
 
-  return silc_packet_send_raw(stream, type, flags,
-                             src_id_type,
-                             src_id_data,
-                             src_id_len,
-                             dst_id_type,
-                             dst_id_data,
-                             dst_id_len,
-                             data, data_len,
-                             cipher,
-                             hmac);
+  ret = silc_packet_send_raw(stream, type, flags,
+                            src_id ? src_id_type : stream->src_id_type,
+                            src_id ? src_id_data : stream->src_id,
+                            src_id ? src_id_len : stream->src_id_len,
+                            dst_id ? dst_id_type : stream->dst_id_type,
+                            dst_id ? dst_id_data : stream->dst_id,
+                            dst_id ? dst_id_len : stream->dst_id_len,
+                            data, data_len,
+                            cipher ? cipher : stream->send_key[0],
+                            hmac ? hmac : stream->send_hmac[0]);
+
+  /* Write the packet to the stream */
+  return ret ? silc_packet_stream_write(stream, FALSE) : FALSE;
 }
 
+/* Sends packet after formatting the arguments to buffer */
+
+SilcBool silc_packet_send_va(SilcPacketStream stream,
+                            SilcPacketType type, SilcPacketFlags flags, ...)
+{
+  SilcBufferStruct buf;
+  SilcBool ret;
+  va_list va;
+
+  va_start(va, flags);
+
+  memset(&buf, 0, sizeof(buf));
+  if (silc_buffer_format_vp(&buf, va) < 0) {
+    va_end(va);
+    return FALSE;
+  }
+
+  ret = silc_packet_send(stream, type, flags, silc_buffer_data(&buf),
+                        silc_buffer_len(&buf));
+
+  silc_buffer_purge(&buf);
+  va_end(va);
+
+  return ret;
+}
+
+/* Sends packet after formatting the arguments to buffer, extended routine */
+
+SilcBool silc_packet_send_va_ext(SilcPacketStream stream,
+                                SilcPacketType type, SilcPacketFlags flags,
+                                SilcIdType src_id_type, void *src_id,
+                                SilcIdType dst_id_type, void *dst_id,
+                                SilcCipher cipher, SilcHmac hmac, ...)
+{
+  SilcBufferStruct buf;
+  SilcBool ret;
+  va_list va;
+
+  va_start(va, hmac);
+
+  memset(&buf, 0, sizeof(buf));
+  if (silc_buffer_format_vp(&buf, va) < 0) {
+    va_end(va);
+    return FALSE;
+  }
+
+  ret = silc_packet_send_ext(stream, type, flags, src_id_type, src_id,
+                            dst_id_type, dst_id, silc_buffer_data(&buf),
+                            silc_buffer_len(&buf), cipher, hmac);
+
+  silc_buffer_purge(&buf);
+  va_end(va);
+
+  return TRUE;
+}
 
 /***************************** Packet Receiving *****************************/
 
 /* Checks MAC in the packet. Returns TRUE if MAC is Ok. */
 
-static SilcBool silc_packet_check_mac(SilcHmac hmac,
-                                     const unsigned char *data,
-                                     SilcUInt32 data_len,
-                                     const unsigned char *packet_mac,
-                                     SilcUInt32 sequence)
+static inline SilcBool silc_packet_check_mac(SilcHmac hmac,
+                                            const unsigned char *data,
+                                            SilcUInt32 data_len,
+                                            const unsigned char *packet_mac,
+                                            const unsigned char *packet_seq,
+                                            SilcUInt32 sequence)
 {
   /* Check MAC */
-  if (hmac) {
+  if (silc_likely(hmac)) {
     unsigned char mac[32], psn[4];
     SilcUInt32 mac_len;
 
@@ -1036,13 +1603,18 @@ static SilcBool silc_packet_check_mac(SilcHmac hmac,
 
     /* Compute HMAC of packet */
     silc_hmac_init(hmac);
-    SILC_PUT32_MSB(sequence, psn);
-    silc_hmac_update(hmac, psn, 4);
+
+    if (!packet_seq) {
+      SILC_PUT32_MSB(sequence, psn);
+      silc_hmac_update(hmac, psn, 4);
+    } else
+      silc_hmac_update(hmac, packet_seq, 4);
+
     silc_hmac_update(hmac, data, data_len);
     silc_hmac_final(hmac, mac, &mac_len);
 
     /* Compare the MAC's */
-    if (memcmp(packet_mac, mac, mac_len)) {
+    if (silc_unlikely(memcmp(packet_mac, mac, mac_len))) {
       SILC_LOG_DEBUG(("MAC failed"));
       return FALSE;
     }
@@ -1053,26 +1625,51 @@ static SilcBool silc_packet_check_mac(SilcHmac hmac,
   return TRUE;
 }
 
+/* Increments/sets counter when decrypting in counter mode. */
+
+static inline void silc_packet_receive_ctr_increment(SilcPacketStream stream,
+                                                    unsigned char *iv,
+                                                    unsigned char *packet_iv)
+{
+  SilcUInt32 pc;
+
+  /* If IV Included flag, set the IV from packet to block counter. */
+  if (stream->iv_included) {
+    memcpy(iv + 4, packet_iv, 8);
+  } else {
+    /* Increment packet counter */
+    SILC_GET32_MSB(pc, iv + 8);
+    pc++;
+    SILC_PUT32_MSB(pc, iv + 8);
+  }
+
+  /* Reset block counter */
+  memset(iv + 12, 0, 4);
+
+  SILC_LOG_HEXDUMP(("Counter Block"), iv, 16);
+}
+
 /* Decrypts SILC packet.  Handles both normal and special packet decryption.
    Return 0 when packet is normal and 1 when it it special, -1 on error. */
 
-static int silc_packet_decrypt(SilcCipher cipher, SilcHmac hmac,
-                              SilcUInt32 sequence, SilcBuffer buffer,
-                              SilcBool normal)
+static inline int silc_packet_decrypt(SilcCipher cipher, SilcHmac hmac,
+                                     SilcUInt32 sequence, SilcBuffer buffer,
+                                     SilcBool normal)
 {
   if (normal == TRUE) {
-    if (cipher) {
+    if (silc_likely(cipher)) {
       /* Decrypt rest of the packet */
       SILC_LOG_DEBUG(("Decrypting the packet"));
-      if (!silc_cipher_decrypt(cipher, buffer->data, buffer->data,
-                              silc_buffer_len(buffer), NULL))
+      if (silc_unlikely(!silc_cipher_decrypt(cipher, buffer->data,
+                                            buffer->data,
+                                            silc_buffer_len(buffer), NULL)))
        return -1;
     }
     return 0;
 
   } else {
     /* Decrypt rest of the header plus padding */
-    if (cipher) {
+    if (silc_likely(cipher)) {
       SilcUInt16 len;
       SilcUInt32 block_len = silc_cipher_get_block_len(cipher);
 
@@ -1086,13 +1683,13 @@ static int silc_packet_decrypt(SilcCipher cipher, SilcHmac hmac,
             block_len);
       silc_buffer_pull(buffer, block_len);
 
-      if (len > silc_buffer_len(buffer)) {
+      if (silc_unlikely(len > silc_buffer_len(buffer))) {
        SILC_LOG_ERROR(("Garbage in header of packet, bad packet length, "
                        "packet dropped"));
        return -1;
       }
-      if (!silc_cipher_decrypt(cipher, buffer->data, buffer->data,
-                              len, NULL))
+      if (silc_unlikely(!silc_cipher_decrypt(cipher, buffer->data,
+                                            buffer->data, len, NULL)))
        return -1;
     }
 
@@ -1104,52 +1701,59 @@ static int silc_packet_decrypt(SilcCipher cipher, SilcHmac hmac,
    parsed. The buffer sent must be already decrypted before calling this
    function. */
 
-static SilcBool silc_packet_parse(SilcPacket packet)
+static inline SilcBool silc_packet_parse(SilcPacket packet)
 {
   SilcBuffer buffer = &packet->buffer;
   SilcUInt8 padlen = (SilcUInt8)buffer->data[4];
   SilcUInt8 src_id_len, dst_id_len, src_id_type, dst_id_type;
-  int len, ret;
+  int ret;
 
   SILC_LOG_DEBUG(("Parsing incoming packet"));
 
   /* Parse the buffer.  This parses the SILC header of the packet. */
-  len = silc_buffer_unformat(buffer,
+  ret = silc_buffer_unformat(buffer,
+                            SILC_STR_ADVANCE,
                             SILC_STR_OFFSET(6),
                             SILC_STR_UI_CHAR(&src_id_len),
                             SILC_STR_UI_CHAR(&dst_id_len),
                             SILC_STR_UI_CHAR(&src_id_type),
                             SILC_STR_END);
-  if (len == -1) {
-    SILC_LOG_ERROR(("Malformed packet header, packet dropped"));
+  if (silc_unlikely(ret == -1)) {
+    if (!packet->stream->udp &&
+       !silc_socket_stream_is_udp(packet->stream->stream, NULL))
+      SILC_LOG_ERROR(("Malformed packet header, packet dropped"));
     return FALSE;
   }
 
-  if (src_id_len > SILC_PACKET_MAX_ID_LEN ||
-      dst_id_len > SILC_PACKET_MAX_ID_LEN) {
-    SILC_LOG_ERROR(("Bad ID lengths in packet (%d and %d)",
-                   packet->src_id_len, packet->dst_id_len));
+  if (silc_unlikely(src_id_len > SILC_PACKET_MAX_ID_LEN ||
+                   dst_id_len > SILC_PACKET_MAX_ID_LEN)) {
+    if (!packet->stream->udp &&
+       !silc_socket_stream_is_udp(packet->stream->stream, NULL))
+      SILC_LOG_ERROR(("Bad ID lengths in packet (%d and %d)",
+                     packet->src_id_len, packet->dst_id_len));
     return FALSE;
   }
 
   ret = silc_buffer_unformat(buffer,
-                            SILC_STR_OFFSET(len),
-                            SILC_STR_UI_XNSTRING(&packet->src_id,
-                                                 src_id_len),
+                            SILC_STR_ADVANCE,
+                            SILC_STR_DATA(&packet->src_id, src_id_len),
                             SILC_STR_UI_CHAR(&dst_id_type),
-                            SILC_STR_UI_XNSTRING(&packet->dst_id,
-                                                 dst_id_len),
+                            SILC_STR_DATA(&packet->dst_id, dst_id_len),
                             SILC_STR_OFFSET(padlen),
                             SILC_STR_END);
-  if (ret == -1) {
-    SILC_LOG_ERROR(("Malformed packet header, packet dropped"));
+  if (silc_unlikely(ret == -1)) {
+    if (!packet->stream->udp &&
+       !silc_socket_stream_is_udp(packet->stream->stream, NULL))
+      SILC_LOG_ERROR(("Malformed packet header, packet dropped"));
     return FALSE;
   }
 
-  if (src_id_type > SILC_ID_CHANNEL ||
-      dst_id_type > SILC_ID_CHANNEL) {
-    SILC_LOG_ERROR(("Bad ID types in packet (%d and %d)",
-                   src_id_type, dst_id_type));
+  if (silc_unlikely(src_id_type > SILC_ID_CHANNEL ||
+                   dst_id_type > SILC_ID_CHANNEL)) {
+    if (!packet->stream->udp &&
+       !silc_socket_stream_is_udp(packet->stream->stream, NULL))
+      SILC_LOG_ERROR(("Bad ID types in packet (%d and %d)",
+                     src_id_type, dst_id_type));
     return FALSE;
   }
 
@@ -1158,12 +1762,9 @@ static SilcBool silc_packet_parse(SilcPacket packet)
   packet->src_id_type = src_id_type;
   packet->dst_id_type = dst_id_type;
 
-  SILC_LOG_HEXDUMP(("Parsed packet, len %d", silc_buffer_len(buffer)),
-                  buffer->data, silc_buffer_len(buffer));
-
-  /* Pull SILC header and padding from packet to get the data payload */
-  silc_buffer_pull(buffer, SILC_PACKET_HEADER_LEN +
-                  packet->src_id_len + packet->dst_id_len + padlen);
+  SILC_LOG_HEXDUMP(("Parsed packet, len %d", silc_buffer_headlen(buffer) +
+                  silc_buffer_len(buffer)), buffer->head,
+                  silc_buffer_headlen(buffer) + silc_buffer_len(buffer));
 
   SILC_LOG_DEBUG(("Incoming packet type: %d (%s)", packet->type,
                  silc_get_packet_name(packet->type)));
@@ -1171,33 +1772,29 @@ static SilcBool silc_packet_parse(SilcPacket packet)
   return TRUE;
 }
 
-/* Dispatch packet to application */
+/* Dispatch packet to application.  Called with stream->lock locked.
+   Returns FALSE if the stream was destroyed while dispatching a packet. */
 
-static void silc_packet_dispatch(SilcPacket packet)
+static SilcBool silc_packet_dispatch(SilcPacket packet)
 {
   SilcPacketStream stream = packet->stream;
   SilcPacketProcess p;
   SilcBool default_sent = FALSE;
   SilcPacketType *pt;
 
-  /* Parse the packet */
-  if (!silc_packet_parse(packet)) {
-    SILC_PACKET_CALLBACK_ERROR(stream, SILC_PACKET_ERR_MALFORMED);
-    silc_packet_free(packet);
-    return;
-  }
-
   /* Dispatch packet to all packet processors that want it */
 
-  if (!stream->process) {
+  if (silc_likely(!stream->process)) {
     /* Send to default processor as no others exist */
     SILC_LOG_DEBUG(("Dispatching packet to default callbacks"));
-    if (!stream->engine->callbacks->
-       packet_receive(stream->engine, stream, packet,
-                      stream->engine->callback_context,
-                      stream->stream_context))
+    silc_mutex_unlock(stream->lock);
+    if (silc_unlikely(!stream->sc->engine->callbacks->
+                     packet_receive(stream->sc->engine, stream, packet,
+                                    stream->sc->engine->callback_context,
+                                    stream->stream_context)))
       silc_packet_free(packet);
-    return;
+    silc_mutex_lock(stream->lock);
+    return stream->destroyed == FALSE;
   }
 
   silc_dlist_start(stream->process);
@@ -1208,137 +1805,225 @@ static void silc_packet_dispatch(SilcPacket packet)
     if (!default_sent && p->priority <= 0) {
       SILC_LOG_DEBUG(("Dispatching packet to default callbacks"));
       default_sent = TRUE;
-      if (stream->engine->callbacks->
-         packet_receive(stream->engine, stream, packet,
-                        stream->engine->callback_context,
+      silc_mutex_unlock(stream->lock);
+      if (stream->sc->engine->callbacks->
+         packet_receive(stream->sc->engine, stream, packet,
+                        stream->sc->engine->callback_context,
                         stream->stream_context)) {
-       return;
+       silc_mutex_lock(stream->lock);
+       return stream->destroyed == FALSE;
       }
+      silc_mutex_lock(stream->lock);
     }
 
     /* Send to processor */
     if (!p->types) {
       /* Send all packet types */
       SILC_LOG_DEBUG(("Dispatching packet to %p callbacks", p->callbacks));
-      if (p->callbacks->packet_receive(stream->engine, stream, packet,
+      silc_mutex_unlock(stream->lock);
+      if (p->callbacks->packet_receive(stream->sc->engine, stream, packet,
                                       p->callback_context,
-                                      stream->stream_context))
-       return;
+                                      stream->stream_context)) {
+       silc_mutex_lock(stream->lock);
+       return stream->destroyed == FALSE;
+      }
+      silc_mutex_lock(stream->lock);
     } else {
       /* Send specific types */
-      for (pt = p->types; *pt; pt++)
-       if (*pt == packet->type) {
-         SILC_LOG_DEBUG(("Dispatching packet to %p callbacks",
-                         p->callbacks));
-         if (p->callbacks->packet_receive(stream->engine, stream, packet,
-                                          p->callback_context,
-                                          stream->stream_context))
-           return;
-         break;
+      for (pt = p->types; *pt; pt++) {
+       if (*pt != packet->type)
+         continue;
+       SILC_LOG_DEBUG(("Dispatching packet to %p callbacks", p->callbacks));
+       silc_mutex_unlock(stream->lock);
+       if (p->callbacks->packet_receive(stream->sc->engine, stream, packet,
+                                        p->callback_context,
+                                        stream->stream_context)) {
+         silc_mutex_lock(stream->lock);
+         return stream->destroyed == FALSE;
        }
+       silc_mutex_lock(stream->lock);
+       break;
+      }
     }
   }
 
   if (!default_sent) {
     /* Send to default processor as it has not been sent yet */
     SILC_LOG_DEBUG(("Dispatching packet to default callbacks"));
-    if (stream->engine->callbacks->
-       packet_receive(stream->engine, stream, packet,
-                      stream->engine->callback_context,
-                      stream->stream_context))
-      return;
+    silc_mutex_unlock(stream->lock);
+    if (stream->sc->engine->callbacks->
+       packet_receive(stream->sc->engine, stream, packet,
+                      stream->sc->engine->callback_context,
+                      stream->stream_context)) {
+      silc_mutex_lock(stream->lock);
+      return stream->destroyed == FALSE;
+    }
+    silc_mutex_lock(stream->lock);
   }
 
   /* If we got here, no one wanted the packet, so drop it */
   silc_packet_free(packet);
+  return stream->destroyed == FALSE;
 }
 
-/* Process incoming data and parse packets. */
+/* Process incoming data and parse packets.  Called with stream->lock
+   locked. */
 
 static void silc_packet_read_process(SilcPacketStream stream)
 {
+  SilcBuffer inbuf = &stream->sc->inbuf;
+  SilcCipher cipher;
+  SilcHmac hmac;
   SilcPacket packet;
+  SilcUInt8 sid;
   SilcUInt16 packetlen;
-  SilcUInt32 paddedlen, mac_len, block_len;
+  SilcUInt32 paddedlen, mac_len, block_len, ivlen, psnlen;
   unsigned char tmp[SILC_PACKET_MIN_HEADER_LEN], *header;
-  unsigned char iv[SILC_CIPHER_MAX_IV_SIZE];
-  SilcBool normal = TRUE;
+  unsigned char iv[SILC_CIPHER_MAX_IV_SIZE], *packet_seq = NULL;
+  SilcBool normal;
   int ret;
 
   /* Parse the packets from the data */
-  while (silc_buffer_len(&stream->inbuf) > 0) {
-
-    if (silc_buffer_len(&stream->inbuf) < SILC_PACKET_MIN_HEADER_LEN) {
+  while (silc_buffer_len(inbuf) > 0) {
+    ivlen = psnlen = 0;
+    cipher = stream->receive_key[0];
+    hmac = stream->receive_hmac[0];
+    normal = FALSE;
+
+    if (silc_unlikely(silc_buffer_len(inbuf) <
+                     (stream->iv_included ? SILC_PACKET_MIN_HEADER_LEN_IV :
+                      SILC_PACKET_MIN_HEADER_LEN))) {
       SILC_LOG_DEBUG(("Partial packet in queue, waiting for the rest"));
       return;
     }
 
-    if (stream->receive_hmac)
-      mac_len = silc_hmac_len(stream->receive_hmac);
+    if (silc_likely(hmac))
+      mac_len = silc_hmac_len(hmac);
     else
       mac_len = 0;
 
     /* Decrypt first block of the packet to get the length field out */
-    if (stream->receive_key) {
-      block_len = silc_cipher_get_block_len(stream->receive_key);
-      memcpy(iv, silc_cipher_get_iv(stream->receive_key), block_len);
-      silc_cipher_decrypt(stream->receive_key, stream->inbuf.data,
-                         tmp, block_len, iv);
+    if (silc_likely(cipher)) {
+      block_len = silc_cipher_get_block_len(cipher);
+
+      if (stream->iv_included) {
+       /* SID, IV and sequence number is included in the ciphertext */
+       sid = (SilcUInt8)inbuf->data[0];
+
+       if (silc_cipher_get_mode(cipher) == SILC_CIPHER_MODE_CTR) {
+         /* Set the CTR mode IV from packet to counter block */
+         memcpy(iv, silc_cipher_get_iv(cipher), block_len);
+         silc_packet_receive_ctr_increment(stream, iv, inbuf->data + 1);
+         ivlen = 8 + 1;
+       } else {
+         /* Get IV from packet */
+         memcpy(iv, inbuf->data + 1, block_len);
+         ivlen = block_len + 1;
+       }
+       psnlen = 4;
+
+       /* Check SID, and get correct decryption key */
+       if (sid != stream->sid) {
+         /* If SID is recent get the previous key and use it */
+         if (sid > 0 && stream->sid > 0 && stream->sid - 1 == sid &&
+             stream->receive_key[1] && !stream->receive_hmac[1]) {
+           cipher = stream->receive_key[1];
+           hmac = stream->receive_hmac[1];
+         } else {
+           /* The SID is unknown, drop rest of the data in buffer */
+           SILC_LOG_DEBUG(("Unknown Security ID %d in packet, expected %d",
+                           sid, stream->sid));
+           silc_mutex_unlock(stream->lock);
+           SILC_PACKET_CALLBACK_ERROR(stream, SILC_PACKET_ERR_UNKNOWN_SID);
+           silc_mutex_lock(stream->lock);
+           silc_buffer_reset(inbuf);
+           return;
+         }
+       }
+      } else {
+       memcpy(iv, silc_cipher_get_iv(cipher), block_len);
+
+       /* If using CTR mode, increment the counter */
+       if (silc_cipher_get_mode(cipher) == SILC_CIPHER_MODE_CTR)
+         silc_packet_receive_ctr_increment(stream, iv, NULL);
+      }
+
+      silc_cipher_decrypt(cipher, inbuf->data + ivlen, tmp,
+                         block_len, iv);
+
       header = tmp;
+      if (stream->iv_included) {
+       /* Take sequence number from packet */
+       packet_seq = header;
+       header += 4;
+      }
     } else {
+      /* Unencrypted packet */
       block_len = SILC_PACKET_MIN_HEADER_LEN;
-      header = stream->inbuf.data;
+      header = inbuf->data;
     }
 
     /* Get packet length and full packet length with padding */
     SILC_PACKET_LENGTH(header, packetlen, paddedlen);
 
     /* Sanity checks */
-    if (packetlen < SILC_PACKET_MIN_LEN) {
-      SILC_LOG_ERROR(("Received too short packet"));
+    if (silc_unlikely(packetlen < SILC_PACKET_MIN_LEN)) {
+      if (!stream->udp && !silc_socket_stream_is_udp(stream->stream, NULL))
+       SILC_LOG_ERROR(("Received too short packet"));
+      silc_mutex_unlock(stream->lock);
       SILC_PACKET_CALLBACK_ERROR(stream, SILC_PACKET_ERR_MALFORMED);
+      silc_mutex_lock(stream->lock);
       memset(tmp, 0, sizeof(tmp));
-      silc_buffer_reset(&stream->inbuf);
+      silc_buffer_reset(inbuf);
       return;
     }
 
-    if (silc_buffer_len(&stream->inbuf) < paddedlen + mac_len) {
+    if (silc_buffer_len(inbuf) < paddedlen + ivlen + mac_len) {
       SILC_LOG_DEBUG(("Received partial packet, waiting for the rest "
                      "(%d bytes)",
-                     paddedlen + mac_len - silc_buffer_len(&stream->inbuf)));
+                     paddedlen + mac_len - silc_buffer_len(inbuf)));
       memset(tmp, 0, sizeof(tmp));
       return;
     }
 
     /* Check MAC of the packet */
-    if (!silc_packet_check_mac(stream->receive_hmac, stream->inbuf.data,
-                              paddedlen, stream->inbuf.data + paddedlen,
-                              stream->receive_psn)) {
+    if (silc_unlikely(!silc_packet_check_mac(hmac, inbuf->data,
+                                            paddedlen + ivlen,
+                                            inbuf->data + ivlen +
+                                            paddedlen, packet_seq,
+                                            stream->receive_psn))) {
+      silc_mutex_unlock(stream->lock);
       SILC_PACKET_CALLBACK_ERROR(stream, SILC_PACKET_ERR_MAC_FAILED);
+      silc_mutex_lock(stream->lock);
       memset(tmp, 0, sizeof(tmp));
-      silc_buffer_reset(&stream->inbuf);
+      silc_buffer_reset(inbuf);
       return;
     }
 
     /* Get packet */
-    packet = silc_packet_alloc(stream->engine);
-    if (!packet) {
+    packet = silc_packet_alloc(stream->sc->engine);
+    if (silc_unlikely(!packet)) {
+      silc_mutex_unlock(stream->lock);
       SILC_PACKET_CALLBACK_ERROR(stream, SILC_PACKET_ERR_NO_MEMORY);
+      silc_mutex_lock(stream->lock);
       memset(tmp, 0, sizeof(tmp));
-      silc_buffer_reset(&stream->inbuf);
+      silc_buffer_reset(inbuf);
       return;
     }
+    packet->stream = stream;
 
     /* Allocate more space to packet buffer, if needed */
-    if (silc_buffer_truelen(&packet->buffer) < paddedlen) {
+    if (silc_unlikely(silc_buffer_truelen(&packet->buffer) < paddedlen)) {
       if (!silc_buffer_realloc(&packet->buffer,
                               silc_buffer_truelen(&packet->buffer) +
                               (paddedlen -
                                silc_buffer_truelen(&packet->buffer)))) {
+       silc_mutex_unlock(stream->lock);
        SILC_PACKET_CALLBACK_ERROR(stream, SILC_PACKET_ERR_NO_MEMORY);
+       silc_mutex_lock(stream->lock);
        silc_packet_free(packet);
        memset(tmp, 0, sizeof(tmp));
-       silc_buffer_reset(&stream->inbuf);
+       silc_buffer_reset(inbuf);
        return;
       }
     }
@@ -1347,7 +2032,7 @@ static void silc_packet_read_process(SilcPacketStream stream)
     packet->flags = (SilcPacketFlags)header[2];
     packet->type = (SilcPacketType)header[3];
 
-    if (stream->engine->local_is_router) {
+    if (stream->sc->engine->local_is_router) {
       if (packet->type == SILC_PACKET_PRIVATE_MESSAGE &&
          (packet->flags & SILC_PACKET_FLAG_PRIVMSG_KEY))
        normal = FALSE;
@@ -1364,21 +2049,24 @@ static void silc_packet_read_process(SilcPacketStream stream)
     }
 
     SILC_LOG_HEXDUMP(("Incoming packet (%d) len %d",
-                     stream->receive_psn, paddedlen + mac_len),
-                    stream->inbuf.data, paddedlen + mac_len);
+                     stream->receive_psn, paddedlen + ivlen + mac_len),
+                    inbuf->data, paddedlen + ivlen + mac_len);
 
     /* Put the decrypted part, and rest of the encrypted data, and decrypt */
     silc_buffer_pull_tail(&packet->buffer, paddedlen);
-    silc_buffer_put(&packet->buffer, header, block_len);
-    silc_buffer_pull(&packet->buffer, block_len);
-    silc_buffer_put(&packet->buffer, stream->inbuf.data + block_len,
-                   paddedlen - block_len);
-    if (stream->receive_key) {
-      silc_cipher_set_iv(stream->receive_key, iv);
-      ret = silc_packet_decrypt(stream->receive_key, stream->receive_hmac,
-                               stream->receive_psn, &packet->buffer, normal);
-      if (ret < 0) {
+    silc_buffer_put(&packet->buffer, header, block_len - psnlen);
+    silc_buffer_pull(&packet->buffer, block_len - psnlen);
+    silc_buffer_put(&packet->buffer, (inbuf->data + ivlen +
+                                     psnlen + (block_len - psnlen)),
+                   paddedlen - ivlen - psnlen - (block_len - psnlen));
+    if (silc_likely(cipher)) {
+      silc_cipher_set_iv(cipher, iv);
+      ret = silc_packet_decrypt(cipher, hmac, stream->receive_psn,
+                               &packet->buffer, normal);
+      if (silc_unlikely(ret < 0)) {
+       silc_mutex_unlock(stream->lock);
        SILC_PACKET_CALLBACK_ERROR(stream, SILC_PACKET_ERR_DECRYPTION_FAILED);
+       silc_mutex_lock(stream->lock);
        silc_packet_free(packet);
        memset(tmp, 0, sizeof(tmp));
        return;
@@ -1389,14 +2077,24 @@ static void silc_packet_read_process(SilcPacketStream stream)
     silc_buffer_push(&packet->buffer, block_len);
 
     /* Pull the packet from inbuf thus we'll get the next one in the inbuf. */
-    silc_buffer_pull(&stream->inbuf, paddedlen + mac_len);
+    silc_buffer_pull(inbuf, paddedlen + mac_len);
+
+    /* Parse the packet */
+    if (silc_unlikely(!silc_packet_parse(packet))) {
+      silc_mutex_unlock(stream->lock);
+      SILC_PACKET_CALLBACK_ERROR(stream, SILC_PACKET_ERR_MALFORMED);
+      silc_mutex_lock(stream->lock);
+      silc_packet_free(packet);
+      memset(tmp, 0, sizeof(tmp));
+      return;
+    }
 
     /* Dispatch the packet to application */
-    packet->stream = stream;
-    silc_packet_dispatch(packet);
+    if (!silc_packet_dispatch(packet))
+      break;
   }
 
-  silc_buffer_reset(&stream->inbuf);
+  silc_buffer_reset(inbuf);
 }
 
 
@@ -1421,7 +2119,7 @@ typedef struct {
   SilcMutex wait_lock;
   SilcCond wait_cond;
   SilcList packet_queue;
-  SilcBool waiting;
+  unsigned int stopped     : 1;
 } *SilcPacketWait;
 
 /* Packet wait receive callback */
@@ -1438,7 +2136,7 @@ silc_packet_wait_packet_receive(SilcPacketEngine engine,
   /* Signal the waiting thread for a new packet */
   silc_mutex_lock(pw->wait_lock);
 
-  if (!pw->waiting) {
+  if (silc_unlikely(pw->stopped)) {
     silc_mutex_unlock(pw->wait_lock);
     return FALSE;
   }
@@ -1494,11 +2192,18 @@ void *silc_packet_wait_init(SilcPacketStream stream, ...)
 
 /* Uninitialize packet waiting */
 
-void silc_packet_wait_uninit(void *context, SilcPacketStream stream)
+void silc_packet_wait_uninit(void *waiter, SilcPacketStream stream)
 {
-  SilcPacketWait pw = context;
+  SilcPacketWait pw = waiter;
   SilcPacket packet;
 
+  /* Signal any threads to stop waiting */
+  silc_mutex_lock(pw->wait_lock);
+  pw->stopped = TRUE;
+  silc_cond_broadcast(pw->wait_cond);
+  silc_mutex_unlock(pw->wait_lock);
+
+  /* Re-acquire lock and free resources */
   silc_mutex_lock(pw->wait_lock);
   silc_packet_stream_unlink(stream, &silc_packet_wait_cbs, pw);
 
@@ -1508,7 +2213,6 @@ void silc_packet_wait_uninit(void *context, SilcPacketStream stream)
     silc_packet_free(packet);
 
   silc_mutex_unlock(pw->wait_lock);
-
   silc_cond_free(pw->wait_cond);
   silc_mutex_free(pw->wait_lock);
   silc_free(pw);
@@ -1516,17 +2220,21 @@ void silc_packet_wait_uninit(void *context, SilcPacketStream stream)
 
 /* Blocks thread until a packet has been received. */
 
-int silc_packet_wait(void *context, int timeout, SilcPacket *return_packet)
+int silc_packet_wait(void *waiter, int timeout, SilcPacket *return_packet)
 {
-  SilcPacketWait pw = context;
+  SilcPacketWait pw = waiter;
   SilcBool ret = FALSE;
 
   silc_mutex_lock(pw->wait_lock);
 
   /* Wait here until packet has arrived */
-  pw->waiting = TRUE;
-  while (silc_list_count(pw->packet_queue) == 0)
+  while (silc_list_count(pw->packet_queue) == 0) {
+    if (silc_unlikely(pw->stopped)) {
+      silc_mutex_unlock(pw->wait_lock);
+      return -1;
+    }
     ret = silc_cond_timedwait(pw->wait_cond, pw->wait_lock, timeout);
+  }
 
   /* Return packet */
   silc_list_start(pw->packet_queue);