- andreas@cvs.openbsd.org 2009/05/27 06:31:25
     [canohost.h canohost.c]
     Add clear_cached_addr(), needed for upcoming changes allowing the peer
     address to change.
     ok markus@
diff --git a/packet.c b/packet.c
index 5afc84c..fdc6488 100644
--- a/packet.c
+++ b/packet.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: packet.c,v 1.160 2009/02/13 11:50:21 markus Exp $ */
+/* $OpenBSD: packet.c,v 1.161 2009/05/25 06:48:01 andreas Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -86,92 +86,117 @@
 
 #define PACKET_MAX_SIZE (256 * 1024)
 
-/*
- * This variable contains the file descriptors used for communicating with
- * the other side.  connection_in is used for reading; connection_out for
- * writing.  These can be the same descriptor, in which case it is assumed to
- * be a socket.
- */
-static int connection_in = -1;
-static int connection_out = -1;
-
-/* Protocol flags for the remote side. */
-static u_int remote_protocol_flags = 0;
-
-/* Encryption context for receiving data.  This is only used for decryption. */
-static CipherContext receive_context;
-
-/* Encryption context for sending data.  This is only used for encryption. */
-static CipherContext send_context;
-
-/* Buffer for raw input data from the socket. */
-Buffer input;
-
-/* Buffer for raw output data going to the socket. */
-Buffer output;
-
-/* Buffer for the partial outgoing packet being constructed. */
-static Buffer outgoing_packet;
-
-/* Buffer for the incoming packet currently being processed. */
-static Buffer incoming_packet;
-
-/* Scratch buffer for packet compression/decompression. */
-static Buffer compression_buffer;
-static int compression_buffer_ready = 0;
-
-/* Flag indicating whether packet compression/decompression is enabled. */
-static int packet_compression = 0;
-
-/* default maximum packet size */
-u_int max_packet_size = 32768;
-
-/* Flag indicating whether this module has been initialized. */
-static int initialized = 0;
-
-/* Set to true if the connection is interactive. */
-static int interactive_mode = 0;
-
-/* Set to true if we are the server side. */
-static int server_side = 0;
-
-/* Set to true if we are authenticated. */
-static int after_authentication = 0;
-
-int keep_alive_timeouts = 0;
-
-/* Set to the maximum time that we will wait to send or receive a packet */
-static int packet_timeout_ms = -1;
-
-/* Session key information for Encryption and MAC */
-Newkeys *newkeys[MODE_MAX];
-static struct packet_state {
+struct packet_state {
 	u_int32_t seqnr;
 	u_int32_t packets;
 	u_int64_t blocks;
 	u_int64_t bytes;
-} p_read, p_send;
-
-static u_int64_t max_blocks_in, max_blocks_out;
-static u_int32_t rekey_limit;
-
-/* Session key for protocol v1 */
-static u_char ssh1_key[SSH_SESSION_KEY_LENGTH];
-static u_int ssh1_keylen;
-
-/* roundup current message to extra_pad bytes */
-static u_char extra_pad = 0;
-
-/* XXX discard incoming data after MAC error */
-static u_int packet_discard = 0;
-static Mac *packet_discard_mac = NULL;
+};
 
 struct packet {
 	TAILQ_ENTRY(packet) next;
 	u_char type;
 	Buffer payload;
 };
-TAILQ_HEAD(, packet) outgoing;
+
+struct session_state {
+	/*
+	 * This variable contains the file descriptors used for
+	 * communicating with the other side.  connection_in is used for
+	 * reading; connection_out for writing.  These can be the same
+	 * descriptor, in which case it is assumed to be a socket.
+	 */
+	int connection_in;
+	int connection_out;
+
+	/* Protocol flags for the remote side. */
+	u_int remote_protocol_flags;
+
+	/* Encryption context for receiving data.  Only used for decryption. */
+	CipherContext receive_context;
+
+	/* Encryption context for sending data.  Only used for encryption. */
+	CipherContext send_context;
+
+	/* Buffer for raw input data from the socket. */
+	Buffer input;
+
+	/* Buffer for raw output data going to the socket. */
+	Buffer output;
+
+	/* Buffer for the partial outgoing packet being constructed. */
+	Buffer outgoing_packet;
+
+	/* Buffer for the incoming packet currently being processed. */
+	Buffer incoming_packet;
+
+	/* Scratch buffer for packet compression/decompression. */
+	Buffer compression_buffer;
+	int compression_buffer_ready;
+
+	/*
+	 * Flag indicating whether packet compression/decompression is
+	 * enabled.
+	 */
+	int packet_compression;
+
+	/* default maximum packet size */
+	u_int max_packet_size;
+
+	/* Flag indicating whether this module has been initialized. */
+	int initialized;
+
+	/* Set to true if the connection is interactive. */
+	int interactive_mode;
+
+	/* Set to true if we are the server side. */
+	int server_side;
+
+	/* Set to true if we are authenticated. */
+	int after_authentication;
+
+	int keep_alive_timeouts;
+
+	/* The maximum time that we will wait to send or receive a packet */
+	int packet_timeout_ms;
+
+	/* Session key information for Encryption and MAC */
+	Newkeys *newkeys[MODE_MAX];
+	struct packet_state p_read, p_send;
+
+	u_int64_t max_blocks_in, max_blocks_out;
+	u_int32_t rekey_limit;
+
+	/* Session key for protocol v1 */
+	u_char ssh1_key[SSH_SESSION_KEY_LENGTH];
+	u_int ssh1_keylen;
+
+	/* roundup current message to extra_pad bytes */
+	u_char extra_pad;
+
+	/* XXX discard incoming data after MAC error */
+	u_int packet_discard;
+	Mac *packet_discard_mac;
+
+	/* Used in packet_read_poll2() */
+	u_int packlen;
+
+	TAILQ_HEAD(, packet) outgoing;
+};
+
+static struct session_state *active_state;
+
+static struct session_state *
+alloc_session_state()
+{
+    struct session_state *s = xcalloc(1, sizeof(*s));
+
+    s->connection_in = -1;
+    s->connection_out = -1;
+    s->max_packet_size = 32768;
+    s->packet_timeout_ms = -1;
+    return s;
+}
 
 /*
  * Sets the descriptors used for communication.  Disables encryption until
@@ -184,21 +209,23 @@
 
 	if (none == NULL)
 		fatal("packet_set_connection: cannot load cipher 'none'");
-	connection_in = fd_in;
-	connection_out = fd_out;
-	cipher_init(&send_context, none, (const u_char *)"",
+	if (active_state == NULL)
+		active_state = alloc_session_state();
+	active_state->connection_in = fd_in;
+	active_state->connection_out = fd_out;
+	cipher_init(&active_state->send_context, none, (const u_char *)"",
 	    0, NULL, 0, CIPHER_ENCRYPT);
-	cipher_init(&receive_context, none, (const u_char *)"",
+	cipher_init(&active_state->receive_context, none, (const u_char *)"",
 	    0, NULL, 0, CIPHER_DECRYPT);
-	newkeys[MODE_IN] = newkeys[MODE_OUT] = NULL;
-	if (!initialized) {
-		initialized = 1;
-		buffer_init(&input);
-		buffer_init(&output);
-		buffer_init(&outgoing_packet);
-		buffer_init(&incoming_packet);
-		TAILQ_INIT(&outgoing);
-		p_send.packets = p_read.packets = 0;
+	active_state->newkeys[MODE_IN] = active_state->newkeys[MODE_OUT] = NULL;
+	if (!active_state->initialized) {
+		active_state->initialized = 1;
+		buffer_init(&active_state->input);
+		buffer_init(&active_state->output);
+		buffer_init(&active_state->outgoing_packet);
+		buffer_init(&active_state->incoming_packet);
+		TAILQ_INIT(&active_state->outgoing);
+		active_state->p_send.packets = active_state->p_read.packets = 0;
 	}
 }
 
@@ -206,27 +233,29 @@
 packet_set_timeout(int timeout, int count)
 {
 	if (timeout == 0 || count == 0) {
-		packet_timeout_ms = -1;
+		active_state->packet_timeout_ms = -1;
 		return;
 	}
 	if ((INT_MAX / 1000) / count < timeout)
-		packet_timeout_ms = INT_MAX;
+		active_state->packet_timeout_ms = INT_MAX;
 	else
-		packet_timeout_ms = timeout * count * 1000;
+		active_state->packet_timeout_ms = timeout * count * 1000;
 }
 
 static void
 packet_stop_discard(void)
 {
-	if (packet_discard_mac) {
+	if (active_state->packet_discard_mac) {
 		char buf[1024];
 		
 		memset(buf, 'a', sizeof(buf));
-		while (buffer_len(&incoming_packet) < PACKET_MAX_SIZE)
-			buffer_append(&incoming_packet, buf, sizeof(buf));
-		(void) mac_compute(packet_discard_mac,
-		    p_read.seqnr,
-		    buffer_ptr(&incoming_packet),
+		while (buffer_len(&active_state->incoming_packet) <
+		    PACKET_MAX_SIZE)
+			buffer_append(&active_state->incoming_packet, buf,
+			    sizeof(buf));
+		(void) mac_compute(active_state->packet_discard_mac,
+		    active_state->p_read.seqnr,
+		    buffer_ptr(&active_state->incoming_packet),
 		    PACKET_MAX_SIZE);
 	}
 	logit("Finished discarding for %.200s", get_remote_ipaddr());
@@ -239,10 +268,11 @@
 	if (enc == NULL || !cipher_is_cbc(enc->cipher))
 		packet_disconnect("Packet corrupt");
 	if (packet_length != PACKET_MAX_SIZE && mac && mac->enabled)
-		packet_discard_mac = mac;
-	if (buffer_len(&input) >= discard)
+		active_state->packet_discard_mac = mac;
+	if (buffer_len(&active_state->input) >= discard)
 		packet_stop_discard();
-	packet_discard = discard - buffer_len(&input);
+	active_state->packet_discard = discard -
+	    buffer_len(&active_state->input);
 }
 
 /* Returns 1 if remote host is connected via socket, 0 if not. */
@@ -254,15 +284,17 @@
 	socklen_t fromlen, tolen;
 
 	/* filedescriptors in and out are the same, so it's a socket */
-	if (connection_in == connection_out)
+	if (active_state->connection_in == active_state->connection_out)
 		return 1;
 	fromlen = sizeof(from);
 	memset(&from, 0, sizeof(from));
-	if (getpeername(connection_in, (struct sockaddr *)&from, &fromlen) < 0)
+	if (getpeername(active_state->connection_in, (struct sockaddr *)&from,
+	    &fromlen) < 0)
 		return 0;
 	tolen = sizeof(to);
 	memset(&to, 0, sizeof(to));
-	if (getpeername(connection_out, (struct sockaddr *)&to, &tolen) < 0)
+	if (getpeername(active_state->connection_out, (struct sockaddr *)&to,
+	    &tolen) < 0)
 		return 0;
 	if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0)
 		return 0;
@@ -283,9 +315,9 @@
 	CipherContext *cc;
 
 	if (mode == MODE_OUT)
-		cc = &send_context;
+		cc = &active_state->send_context;
 	else
-		cc = &receive_context;
+		cc = &active_state->receive_context;
 
 	cipher_get_keyiv(cc, iv, len);
 }
@@ -296,9 +328,9 @@
 	CipherContext *cc;
 
 	if (mode == MODE_OUT)
-		cc = &send_context;
+		cc = &active_state->send_context;
 	else
-		cc = &receive_context;
+		cc = &active_state->receive_context;
 
 	return (cipher_get_keycontext(cc, dat));
 }
@@ -309,9 +341,9 @@
 	CipherContext *cc;
 
 	if (mode == MODE_OUT)
-		cc = &send_context;
+		cc = &active_state->send_context;
 	else
-		cc = &receive_context;
+		cc = &active_state->receive_context;
 
 	cipher_set_keycontext(cc, dat);
 }
@@ -322,9 +354,9 @@
 	CipherContext *cc;
 
 	if (mode == MODE_OUT)
-		cc = &send_context;
+		cc = &active_state->send_context;
 	else
-		cc = &receive_context;
+		cc = &active_state->receive_context;
 
 	return (cipher_get_keyiv_len(cc));
 }
@@ -335,9 +367,9 @@
 	CipherContext *cc;
 
 	if (mode == MODE_OUT)
-		cc = &send_context;
+		cc = &active_state->send_context;
 	else
-		cc = &receive_context;
+		cc = &active_state->receive_context;
 
 	cipher_set_keyiv(cc, dat);
 }
@@ -345,7 +377,7 @@
 int
 packet_get_ssh1_cipher(void)
 {
-	return (cipher_get_number(receive_context.cipher));
+	return (cipher_get_number(active_state->receive_context.cipher));
 }
 
 void
@@ -354,7 +386,8 @@
 {
 	struct packet_state *state;
 
-	state = (mode == MODE_IN) ? &p_read : &p_send;
+	state = (mode == MODE_IN) ?
+	    &active_state->p_read : &active_state->p_send;
 	if (seqnr)
 		*seqnr = state->seqnr;
 	if (blocks)
@@ -371,7 +404,8 @@
 {
 	struct packet_state *state;
 
-	state = (mode == MODE_IN) ? &p_read : &p_send;
+	state = (mode == MODE_IN) ?
+	    &active_state->p_read : &active_state->p_send;
 	state->seqnr = seqnr;
 	state->blocks = blocks;
 	state->packets = packets;
@@ -387,7 +421,8 @@
 	socklen_t tolen = sizeof(to);
 
 	memset(&to, 0, sizeof(to));
-	if (getsockname(connection_out, (struct sockaddr *)&to, &tolen) < 0)
+	if (getsockname(active_state->connection_out, (struct sockaddr *)&to,
+	    &tolen) < 0)
 		return 0;
 	if (to.ss_family == AF_INET)
 		return 1;
@@ -405,10 +440,10 @@
 packet_set_nonblocking(void)
 {
 	/* Set the socket into non-blocking mode. */
-	set_nonblock(connection_in);
+	set_nonblock(active_state->connection_in);
 
-	if (connection_out != connection_in)
-		set_nonblock(connection_out);
+	if (active_state->connection_out != active_state->connection_in)
+		set_nonblock(active_state->connection_out);
 }
 
 /* Returns the socket used for reading. */
@@ -416,7 +451,7 @@
 int
 packet_get_connection_in(void)
 {
-	return connection_in;
+	return active_state->connection_in;
 }
 
 /* Returns the descriptor used for writing. */
@@ -424,7 +459,7 @@
 int
 packet_get_connection_out(void)
 {
-	return connection_out;
+	return active_state->connection_out;
 }
 
 /* Closes the connection and clears and frees internal data structures. */
@@ -432,26 +467,26 @@
 void
 packet_close(void)
 {
-	if (!initialized)
+	if (!active_state->initialized)
 		return;
-	initialized = 0;
-	if (connection_in == connection_out) {
-		shutdown(connection_out, SHUT_RDWR);
-		close(connection_out);
+	active_state->initialized = 0;
+	if (active_state->connection_in == active_state->connection_out) {
+		shutdown(active_state->connection_out, SHUT_RDWR);
+		close(active_state->connection_out);
 	} else {
-		close(connection_in);
-		close(connection_out);
+		close(active_state->connection_in);
+		close(active_state->connection_out);
 	}
-	buffer_free(&input);
-	buffer_free(&output);
-	buffer_free(&outgoing_packet);
-	buffer_free(&incoming_packet);
-	if (compression_buffer_ready) {
-		buffer_free(&compression_buffer);
+	buffer_free(&active_state->input);
+	buffer_free(&active_state->output);
+	buffer_free(&active_state->outgoing_packet);
+	buffer_free(&active_state->incoming_packet);
+	if (active_state->compression_buffer_ready) {
+		buffer_free(&active_state->compression_buffer);
 		buffer_compress_uninit();
 	}
-	cipher_cleanup(&send_context);
-	cipher_cleanup(&receive_context);
+	cipher_cleanup(&active_state->send_context);
+	cipher_cleanup(&active_state->receive_context);
 }
 
 /* Sets remote side protocol flags. */
@@ -459,7 +494,7 @@
 void
 packet_set_protocol_flags(u_int protocol_flags)
 {
-	remote_protocol_flags = protocol_flags;
+	active_state->remote_protocol_flags = protocol_flags;
 }
 
 /* Returns the remote protocol flags set earlier by the above function. */
@@ -467,7 +502,7 @@
 u_int
 packet_get_protocol_flags(void)
 {
-	return remote_protocol_flags;
+	return active_state->remote_protocol_flags;
 }
 
 /*
@@ -478,18 +513,18 @@
 static void
 packet_init_compression(void)
 {
-	if (compression_buffer_ready == 1)
+	if (active_state->compression_buffer_ready == 1)
 		return;
-	compression_buffer_ready = 1;
-	buffer_init(&compression_buffer);
+	active_state->compression_buffer_ready = 1;
+	buffer_init(&active_state->compression_buffer);
 }
 
 void
 packet_start_compression(int level)
 {
-	if (packet_compression && !compat20)
+	if (active_state->packet_compression && !compat20)
 		fatal("Compression already enabled.");
-	packet_compression = 1;
+	active_state->packet_compression = 1;
 	packet_init_compression();
 	buffer_compress_init_send(level);
 	buffer_compress_init_recv();
@@ -513,19 +548,21 @@
 		fatal("packet_set_encryption_key: keylen too small: %d", keylen);
 	if (keylen > SSH_SESSION_KEY_LENGTH)
 		fatal("packet_set_encryption_key: keylen too big: %d", keylen);
-	memcpy(ssh1_key, key, keylen);
-	ssh1_keylen = keylen;
-	cipher_init(&send_context, cipher, key, keylen, NULL, 0, CIPHER_ENCRYPT);
-	cipher_init(&receive_context, cipher, key, keylen, NULL, 0, CIPHER_DECRYPT);
+	memcpy(active_state->ssh1_key, key, keylen);
+	active_state->ssh1_keylen = keylen;
+	cipher_init(&active_state->send_context, cipher, key, keylen, NULL,
+	    0, CIPHER_ENCRYPT);
+	cipher_init(&active_state->receive_context, cipher, key, keylen, NULL,
+	    0, CIPHER_DECRYPT);
 }
 
 u_int
 packet_get_encryption_key(u_char *key)
 {
 	if (key == NULL)
-		return (ssh1_keylen);
-	memcpy(key, ssh1_key, ssh1_keylen);
-	return (ssh1_keylen);
+		return (active_state->ssh1_keylen);
+	memcpy(key, active_state->ssh1_key, active_state->ssh1_keylen);
+	return (active_state->ssh1_keylen);
 }
 
 /* Start constructing a packet to send. */
@@ -539,8 +576,8 @@
 	len = compat20 ? 6 : 9;
 	memset(buf, 0, len - 1);
 	buf[len - 1] = type;
-	buffer_clear(&outgoing_packet);
-	buffer_append(&outgoing_packet, buf, len);
+	buffer_clear(&active_state->outgoing_packet);
+	buffer_append(&active_state->outgoing_packet, buf, len);
 }
 
 /* Append payload. */
@@ -549,43 +586,43 @@
 {
 	char ch = value;
 
-	buffer_append(&outgoing_packet, &ch, 1);
+	buffer_append(&active_state->outgoing_packet, &ch, 1);
 }
 
 void
 packet_put_int(u_int value)
 {
-	buffer_put_int(&outgoing_packet, value);
+	buffer_put_int(&active_state->outgoing_packet, value);
 }
 
 void
 packet_put_string(const void *buf, u_int len)
 {
-	buffer_put_string(&outgoing_packet, buf, len);
+	buffer_put_string(&active_state->outgoing_packet, buf, len);
 }
 
 void
 packet_put_cstring(const char *str)
 {
-	buffer_put_cstring(&outgoing_packet, str);
+	buffer_put_cstring(&active_state->outgoing_packet, str);
 }
 
 void
 packet_put_raw(const void *buf, u_int len)
 {
-	buffer_append(&outgoing_packet, buf, len);
+	buffer_append(&active_state->outgoing_packet, buf, len);
 }
 
 void
 packet_put_bignum(BIGNUM * value)
 {
-	buffer_put_bignum(&outgoing_packet, value);
+	buffer_put_bignum(&active_state->outgoing_packet, value);
 }
 
 void
 packet_put_bignum2(BIGNUM * value)
 {
-	buffer_put_bignum2(&outgoing_packet, value);
+	buffer_put_bignum2(&active_state->outgoing_packet, value);
 }
 
 /*
@@ -605,24 +642,27 @@
 	 * If using packet compression, compress the payload of the outgoing
 	 * packet.
 	 */
-	if (packet_compression) {
-		buffer_clear(&compression_buffer);
+	if (active_state->packet_compression) {
+		buffer_clear(&active_state->compression_buffer);
 		/* Skip padding. */
-		buffer_consume(&outgoing_packet, 8);
+		buffer_consume(&active_state->outgoing_packet, 8);
 		/* padding */
-		buffer_append(&compression_buffer, "\0\0\0\0\0\0\0\0", 8);
-		buffer_compress(&outgoing_packet, &compression_buffer);
-		buffer_clear(&outgoing_packet);
-		buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer),
-		    buffer_len(&compression_buffer));
+		buffer_append(&active_state->compression_buffer,
+		    "\0\0\0\0\0\0\0\0", 8);
+		buffer_compress(&active_state->outgoing_packet,
+		    &active_state->compression_buffer);
+		buffer_clear(&active_state->outgoing_packet);
+		buffer_append(&active_state->outgoing_packet,
+		    buffer_ptr(&active_state->compression_buffer),
+		    buffer_len(&active_state->compression_buffer));
 	}
 	/* Compute packet length without padding (add checksum, remove padding). */
-	len = buffer_len(&outgoing_packet) + 4 - 8;
+	len = buffer_len(&active_state->outgoing_packet) + 4 - 8;
 
 	/* Insert padding. Initialized to zero in packet_start1() */
 	padding = 8 - len % 8;
-	if (!send_context.plaintext) {
-		cp = buffer_ptr(&outgoing_packet);
+	if (!active_state->send_context.plaintext) {
+		cp = buffer_ptr(&active_state->outgoing_packet);
 		for (i = 0; i < padding; i++) {
 			if (i % 4 == 0)
 				rnd = arc4random();
@@ -630,33 +670,36 @@
 			rnd >>= 8;
 		}
 	}
-	buffer_consume(&outgoing_packet, 8 - padding);
+	buffer_consume(&active_state->outgoing_packet, 8 - padding);
 
 	/* Add check bytes. */
-	checksum = ssh_crc32(buffer_ptr(&outgoing_packet),
-	    buffer_len(&outgoing_packet));
+	checksum = ssh_crc32(buffer_ptr(&active_state->outgoing_packet),
+	    buffer_len(&active_state->outgoing_packet));
 	put_u32(buf, checksum);
-	buffer_append(&outgoing_packet, buf, 4);
+	buffer_append(&active_state->outgoing_packet, buf, 4);
 
 #ifdef PACKET_DEBUG
 	fprintf(stderr, "packet_send plain: ");
-	buffer_dump(&outgoing_packet);
+	buffer_dump(&active_state->outgoing_packet);
 #endif
 
 	/* Append to output. */
 	put_u32(buf, len);
-	buffer_append(&output, buf, 4);
-	cp = buffer_append_space(&output, buffer_len(&outgoing_packet));
-	cipher_crypt(&send_context, cp, buffer_ptr(&outgoing_packet),
-	    buffer_len(&outgoing_packet));
+	buffer_append(&active_state->output, buf, 4);
+	cp = buffer_append_space(&active_state->output,
+	    buffer_len(&active_state->outgoing_packet));
+	cipher_crypt(&active_state->send_context, cp,
+	    buffer_ptr(&active_state->outgoing_packet),
+	    buffer_len(&active_state->outgoing_packet));
 
 #ifdef PACKET_DEBUG
 	fprintf(stderr, "encrypted: ");
-	buffer_dump(&output);
+	buffer_dump(&active_state->output);
 #endif
-	p_send.packets++;
-	p_send.bytes += len + buffer_len(&outgoing_packet);
-	buffer_clear(&outgoing_packet);
+	active_state->p_send.packets++;
+	active_state->p_send.bytes += len +
+	    buffer_len(&active_state->outgoing_packet);
+	buffer_clear(&active_state->outgoing_packet);
 
 	/*
 	 * Note that the packet is now only buffered in output.  It won't be
@@ -678,22 +721,22 @@
 	debug2("set_newkeys: mode %d", mode);
 
 	if (mode == MODE_OUT) {
-		cc = &send_context;
+		cc = &active_state->send_context;
 		crypt_type = CIPHER_ENCRYPT;
-		p_send.packets = p_send.blocks = 0;
-		max_blocks = &max_blocks_out;
+		active_state->p_send.packets = active_state->p_send.blocks = 0;
+		max_blocks = &active_state->max_blocks_out;
 	} else {
-		cc = &receive_context;
+		cc = &active_state->receive_context;
 		crypt_type = CIPHER_DECRYPT;
-		p_read.packets = p_read.blocks = 0;
-		max_blocks = &max_blocks_in;
+		active_state->p_read.packets = active_state->p_read.blocks = 0;
+		max_blocks = &active_state->max_blocks_in;
 	}
-	if (newkeys[mode] != NULL) {
+	if (active_state->newkeys[mode] != NULL) {
 		debug("set_newkeys: rekeying");
 		cipher_cleanup(cc);
-		enc  = &newkeys[mode]->enc;
-		mac  = &newkeys[mode]->mac;
-		comp = &newkeys[mode]->comp;
+		enc  = &active_state->newkeys[mode]->enc;
+		mac  = &active_state->newkeys[mode]->mac;
+		comp = &active_state->newkeys[mode]->comp;
 		mac_clear(mac);
 		xfree(enc->name);
 		xfree(enc->iv);
@@ -701,14 +744,14 @@
 		xfree(mac->name);
 		xfree(mac->key);
 		xfree(comp->name);
-		xfree(newkeys[mode]);
+		xfree(active_state->newkeys[mode]);
 	}
-	newkeys[mode] = kex_get_newkeys(mode);
-	if (newkeys[mode] == NULL)
+	active_state->newkeys[mode] = kex_get_newkeys(mode);
+	if (active_state->newkeys[mode] == NULL)
 		fatal("newkeys: no keys for mode %d", mode);
-	enc  = &newkeys[mode]->enc;
-	mac  = &newkeys[mode]->mac;
-	comp = &newkeys[mode]->comp;
+	enc  = &active_state->newkeys[mode]->enc;
+	mac  = &active_state->newkeys[mode]->mac;
+	comp = &active_state->newkeys[mode]->comp;
 	if (mac_init(mac) == 0)
 		mac->enabled = 1;
 	DBG(debug("cipher_init_context: %d", mode));
@@ -719,8 +762,8 @@
 	   memset(enc->key, 0, enc->key_len);
 	   memset(mac->key, 0, mac->key_len); */
 	if ((comp->type == COMP_ZLIB ||
-	    (comp->type == COMP_DELAYED && after_authentication)) &&
-	    comp->enabled == 0) {
+	    (comp->type == COMP_DELAYED &&
+	     active_state->after_authentication)) && comp->enabled == 0) {
 		packet_init_compression();
 		if (mode == MODE_OUT)
 			buffer_compress_init_send(6);
@@ -736,8 +779,9 @@
 		*max_blocks = (u_int64_t)1 << (enc->block_size*2);
 	else
 		*max_blocks = ((u_int64_t)1 << 30) / enc->block_size;
-	if (rekey_limit)
-		*max_blocks = MIN(*max_blocks, rekey_limit / enc->block_size);
+	if (active_state->rekey_limit)
+		*max_blocks = MIN(*max_blocks,
+		    active_state->rekey_limit / enc->block_size);
 }
 
 /*
@@ -755,12 +799,12 @@
 	 * Remember that we are past the authentication step, so rekeying
 	 * with COMP_DELAYED will turn on compression immediately.
 	 */
-	after_authentication = 1;
+	active_state->after_authentication = 1;
 	for (mode = 0; mode < MODE_MAX; mode++) {
 		/* protocol error: USERAUTH_SUCCESS received before NEWKEYS */
-		if (newkeys[mode] == NULL)
+		if (active_state->newkeys[mode] == NULL)
 			continue;
-		comp = &newkeys[mode]->comp;
+		comp = &active_state->newkeys[mode]->comp;
 		if (comp && !comp->enabled && comp->type == COMP_DELAYED) {
 			packet_init_compression();
 			if (mode == MODE_OUT)
@@ -788,37 +832,39 @@
 	Comp *comp = NULL;
 	int block_size;
 
-	if (newkeys[MODE_OUT] != NULL) {
-		enc  = &newkeys[MODE_OUT]->enc;
-		mac  = &newkeys[MODE_OUT]->mac;
-		comp = &newkeys[MODE_OUT]->comp;
+	if (active_state->newkeys[MODE_OUT] != NULL) {
+		enc  = &active_state->newkeys[MODE_OUT]->enc;
+		mac  = &active_state->newkeys[MODE_OUT]->mac;
+		comp = &active_state->newkeys[MODE_OUT]->comp;
 	}
 	block_size = enc ? enc->block_size : 8;
 
-	cp = buffer_ptr(&outgoing_packet);
+	cp = buffer_ptr(&active_state->outgoing_packet);
 	type = cp[5];
 
 #ifdef PACKET_DEBUG
 	fprintf(stderr, "plain:     ");
-	buffer_dump(&outgoing_packet);
+	buffer_dump(&active_state->outgoing_packet);
 #endif
 
 	if (comp && comp->enabled) {
-		len = buffer_len(&outgoing_packet);
+		len = buffer_len(&active_state->outgoing_packet);
 		/* skip header, compress only payload */
-		buffer_consume(&outgoing_packet, 5);
-		buffer_clear(&compression_buffer);
-		buffer_compress(&outgoing_packet, &compression_buffer);
-		buffer_clear(&outgoing_packet);
-		buffer_append(&outgoing_packet, "\0\0\0\0\0", 5);
-		buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer),
-		    buffer_len(&compression_buffer));
+		buffer_consume(&active_state->outgoing_packet, 5);
+		buffer_clear(&active_state->compression_buffer);
+		buffer_compress(&active_state->outgoing_packet,
+		    &active_state->compression_buffer);
+		buffer_clear(&active_state->outgoing_packet);
+		buffer_append(&active_state->outgoing_packet, "\0\0\0\0\0", 5);
+		buffer_append(&active_state->outgoing_packet,
+		    buffer_ptr(&active_state->compression_buffer),
+		    buffer_len(&active_state->compression_buffer));
 		DBG(debug("compression: raw %d compressed %d", len,
-		    buffer_len(&outgoing_packet)));
+		    buffer_len(&active_state->outgoing_packet)));
 	}
 
 	/* sizeof (packet_len + pad_len + payload) */
-	len = buffer_len(&outgoing_packet);
+	len = buffer_len(&active_state->outgoing_packet);
 
 	/*
 	 * calc size of padding, alloc space, get random data,
@@ -827,17 +873,19 @@
 	padlen = block_size - (len % block_size);
 	if (padlen < 4)
 		padlen += block_size;
-	if (extra_pad) {
+	if (active_state->extra_pad) {
 		/* will wrap if extra_pad+padlen > 255 */
-		extra_pad  = roundup(extra_pad, block_size);
-		pad = extra_pad - ((len + padlen) % extra_pad);
+		active_state->extra_pad =
+		    roundup(active_state->extra_pad, block_size);
+		pad = active_state->extra_pad -
+		    ((len + padlen) % active_state->extra_pad);
 		debug3("packet_send2: adding %d (len %d padlen %d extra_pad %d)",
-		    pad, len, padlen, extra_pad);
+		    pad, len, padlen, active_state->extra_pad);
 		padlen += pad;
-		extra_pad = 0;
+		active_state->extra_pad = 0;
 	}
-	cp = buffer_append_space(&outgoing_packet, padlen);
-	if (enc && !send_context.plaintext) {
+	cp = buffer_append_space(&active_state->outgoing_packet, padlen);
+	if (enc && !active_state->send_context.plaintext) {
 		/* random padding */
 		for (i = 0; i < padlen; i++) {
 			if (i % 4 == 0)
@@ -850,43 +898,45 @@
 		memset(cp, 0, padlen);
 	}
 	/* packet_length includes payload, padding and padding length field */
-	packet_length = buffer_len(&outgoing_packet) - 4;
-	cp = buffer_ptr(&outgoing_packet);
+	packet_length = buffer_len(&active_state->outgoing_packet) - 4;
+	cp = buffer_ptr(&active_state->outgoing_packet);
 	put_u32(cp, packet_length);
 	cp[4] = padlen;
 	DBG(debug("send: len %d (includes padlen %d)", packet_length+4, padlen));
 
 	/* compute MAC over seqnr and packet(length fields, payload, padding) */
 	if (mac && mac->enabled) {
-		macbuf = mac_compute(mac, p_send.seqnr,
-		    buffer_ptr(&outgoing_packet),
-		    buffer_len(&outgoing_packet));
-		DBG(debug("done calc MAC out #%d", p_send.seqnr));
+		macbuf = mac_compute(mac, active_state->p_send.seqnr,
+		    buffer_ptr(&active_state->outgoing_packet),
+		    buffer_len(&active_state->outgoing_packet));
+		DBG(debug("done calc MAC out #%d", active_state->p_send.seqnr));
 	}
 	/* encrypt packet and append to output buffer. */
-	cp = buffer_append_space(&output, buffer_len(&outgoing_packet));
-	cipher_crypt(&send_context, cp, buffer_ptr(&outgoing_packet),
-	    buffer_len(&outgoing_packet));
+	cp = buffer_append_space(&active_state->output,
+	    buffer_len(&active_state->outgoing_packet));
+	cipher_crypt(&active_state->send_context, cp,
+	    buffer_ptr(&active_state->outgoing_packet),
+	    buffer_len(&active_state->outgoing_packet));
 	/* append unencrypted MAC */
 	if (mac && mac->enabled)
-		buffer_append(&output, macbuf, mac->mac_len);
+		buffer_append(&active_state->output, macbuf, mac->mac_len);
 #ifdef PACKET_DEBUG
 	fprintf(stderr, "encrypted: ");
-	buffer_dump(&output);
+	buffer_dump(&active_state->output);
 #endif
 	/* increment sequence number for outgoing packets */
-	if (++p_send.seqnr == 0)
+	if (++active_state->p_send.seqnr == 0)
 		logit("outgoing seqnr wraps around");
-	if (++p_send.packets == 0)
+	if (++active_state->p_send.packets == 0)
 		if (!(datafellows & SSH_BUG_NOREKEY))
 			fatal("XXX too many packets with same key");
-	p_send.blocks += (packet_length + 4) / block_size;
-	p_send.bytes += packet_length + 4;
-	buffer_clear(&outgoing_packet);
+	active_state->p_send.blocks += (packet_length + 4) / block_size;
+	active_state->p_send.bytes += packet_length + 4;
+	buffer_clear(&active_state->outgoing_packet);
 
 	if (type == SSH2_MSG_NEWKEYS)
 		set_newkeys(MODE_OUT);
-	else if (type == SSH2_MSG_USERAUTH_SUCCESS && server_side)
+	else if (type == SSH2_MSG_USERAUTH_SUCCESS && active_state->server_side)
 		packet_enable_delayed_compress();
 }
 
@@ -897,7 +947,7 @@
 	struct packet *p;
 	u_char type, *cp;
 
-	cp = buffer_ptr(&outgoing_packet);
+	cp = buffer_ptr(&active_state->outgoing_packet);
 	type = cp[5];
 
 	/* during rekeying we can only send key exchange messages */
@@ -907,9 +957,10 @@
 			debug("enqueue packet: %u", type);
 			p = xmalloc(sizeof(*p));
 			p->type = type;
-			memcpy(&p->payload, &outgoing_packet, sizeof(Buffer));
-			buffer_init(&outgoing_packet);
-			TAILQ_INSERT_TAIL(&outgoing, p, next);
+			memcpy(&p->payload, &active_state->outgoing_packet,
+			    sizeof(Buffer));
+			buffer_init(&active_state->outgoing_packet);
+			TAILQ_INSERT_TAIL(&active_state->outgoing, p, next);
 			return;
 		}
 	}
@@ -923,13 +974,13 @@
 	/* after a NEWKEYS message we can send the complete queue */
 	if (type == SSH2_MSG_NEWKEYS) {
 		rekeying = 0;
-		while ((p = TAILQ_FIRST(&outgoing))) {
+		while ((p = TAILQ_FIRST(&active_state->outgoing))) {
 			type = p->type;
 			debug("dequeue packet: %u", type);
-			buffer_free(&outgoing_packet);
-			memcpy(&outgoing_packet, &p->payload,
+			buffer_free(&active_state->outgoing_packet);
+			memcpy(&active_state->outgoing_packet, &p->payload,
 			    sizeof(Buffer));
-			TAILQ_REMOVE(&outgoing, p, next);
+			TAILQ_REMOVE(&active_state->outgoing, p, next);
 			xfree(p);
 			packet_send2_wrapped();
 		}
@@ -962,8 +1013,8 @@
 
 	DBG(debug("packet_read()"));
 
-	setp = (fd_set *)xcalloc(howmany(connection_in+1, NFDBITS),
-	    sizeof(fd_mask));
+	setp = (fd_set *)xcalloc(howmany(active_state->connection_in + 1,
+	    NFDBITS), sizeof(fd_mask));
 
 	/* Since we are blocking, ensure that all written packets have been sent. */
 	packet_write_wait();
@@ -987,27 +1038,27 @@
 		 * Otherwise, wait for some data to arrive, add it to the
 		 * buffer, and try again.
 		 */
-		memset(setp, 0, howmany(connection_in + 1, NFDBITS) *
-		    sizeof(fd_mask));
-		FD_SET(connection_in, setp);
+		memset(setp, 0, howmany(active_state->connection_in + 1,
+		    NFDBITS) * sizeof(fd_mask));
+		FD_SET(active_state->connection_in, setp);
 
-		if (packet_timeout_ms > 0) {
-			ms_remain = packet_timeout_ms;
+		if (active_state->packet_timeout_ms > 0) {
+			ms_remain = active_state->packet_timeout_ms;
 			timeoutp = &timeout;
 		}
 		/* Wait for some data to arrive. */
 		for (;;) {
-			if (packet_timeout_ms != -1) {
+			if (active_state->packet_timeout_ms != -1) {
 				ms_to_timeval(&timeout, ms_remain);
 				gettimeofday(&start, NULL);
 			}
-			if ((ret = select(connection_in + 1, setp, NULL,
-			    NULL, timeoutp)) >= 0)
+			if ((ret = select(active_state->connection_in + 1, setp,
+			    NULL, NULL, timeoutp)) >= 0)
 				break;
-		   	if (errno != EAGAIN && errno != EINTR &&
+			if (errno != EAGAIN && errno != EINTR &&
 			    errno != EWOULDBLOCK)
 				break;
-			if (packet_timeout_ms == -1)
+			if (active_state->packet_timeout_ms == -1)
 				continue;
 			ms_subtract_diff(&start, &ms_remain);
 			if (ms_remain <= 0) {
@@ -1021,7 +1072,7 @@
 			cleanup_exit(255);
 		}
 		/* Read data from the socket. */
-		len = read(connection_in, buf, sizeof(buf));
+		len = read(active_state->connection_in, buf, sizeof(buf));
 		if (len == 0) {
 			logit("Connection closed by %.200s", get_remote_ipaddr());
 			cleanup_exit(255);
@@ -1073,31 +1124,32 @@
 	u_int checksum, stored_checksum;
 
 	/* Check if input size is less than minimum packet size. */
-	if (buffer_len(&input) < 4 + 8)
+	if (buffer_len(&active_state->input) < 4 + 8)
 		return SSH_MSG_NONE;
 	/* Get length of incoming packet. */
-	cp = buffer_ptr(&input);
+	cp = buffer_ptr(&active_state->input);
 	len = get_u32(cp);
 	if (len < 1 + 2 + 2 || len > 256 * 1024)
 		packet_disconnect("Bad packet length %u.", len);
 	padded_len = (len + 8) & ~7;
 
 	/* Check if the packet has been entirely received. */
-	if (buffer_len(&input) < 4 + padded_len)
+	if (buffer_len(&active_state->input) < 4 + padded_len)
 		return SSH_MSG_NONE;
 
 	/* The entire packet is in buffer. */
 
 	/* Consume packet length. */
-	buffer_consume(&input, 4);
+	buffer_consume(&active_state->input, 4);
 
 	/*
 	 * Cryptographic attack detector for ssh
 	 * (C)1998 CORE-SDI, Buenos Aires Argentina
 	 * Ariel Futoransky(futo@core-sdi.com)
 	 */
-	if (!receive_context.plaintext) {
-		switch (detect_attack(buffer_ptr(&input), padded_len)) {
+	if (!active_state->receive_context.plaintext) {
+		switch (detect_attack(buffer_ptr(&active_state->input),
+		    padded_len)) {
 		case DEATTACK_DETECTED:
 			packet_disconnect("crc32 compensation attack: "
 			    "network attack detected");
@@ -1108,45 +1160,48 @@
 	}
 
 	/* Decrypt data to incoming_packet. */
-	buffer_clear(&incoming_packet);
-	cp = buffer_append_space(&incoming_packet, padded_len);
-	cipher_crypt(&receive_context, cp, buffer_ptr(&input), padded_len);
+	buffer_clear(&active_state->incoming_packet);
+	cp = buffer_append_space(&active_state->incoming_packet, padded_len);
+	cipher_crypt(&active_state->receive_context, cp,
+	    buffer_ptr(&active_state->input), padded_len);
 
-	buffer_consume(&input, padded_len);
+	buffer_consume(&active_state->input, padded_len);
 
 #ifdef PACKET_DEBUG
 	fprintf(stderr, "read_poll plain: ");
-	buffer_dump(&incoming_packet);
+	buffer_dump(&active_state->incoming_packet);
 #endif
 
 	/* Compute packet checksum. */
-	checksum = ssh_crc32(buffer_ptr(&incoming_packet),
-	    buffer_len(&incoming_packet) - 4);
+	checksum = ssh_crc32(buffer_ptr(&active_state->incoming_packet),
+	    buffer_len(&active_state->incoming_packet) - 4);
 
 	/* Skip padding. */
-	buffer_consume(&incoming_packet, 8 - len % 8);
+	buffer_consume(&active_state->incoming_packet, 8 - len % 8);
 
 	/* Test check bytes. */
-	if (len != buffer_len(&incoming_packet))
+	if (len != buffer_len(&active_state->incoming_packet))
 		packet_disconnect("packet_read_poll1: len %d != buffer_len %d.",
-		    len, buffer_len(&incoming_packet));
+		    len, buffer_len(&active_state->incoming_packet));
 
-	cp = (u_char *)buffer_ptr(&incoming_packet) + len - 4;
+	cp = (u_char *)buffer_ptr(&active_state->incoming_packet) + len - 4;
 	stored_checksum = get_u32(cp);
 	if (checksum != stored_checksum)
 		packet_disconnect("Corrupted check bytes on input.");
-	buffer_consume_end(&incoming_packet, 4);
+	buffer_consume_end(&active_state->incoming_packet, 4);
 
-	if (packet_compression) {
-		buffer_clear(&compression_buffer);
-		buffer_uncompress(&incoming_packet, &compression_buffer);
-		buffer_clear(&incoming_packet);
-		buffer_append(&incoming_packet, buffer_ptr(&compression_buffer),
-		    buffer_len(&compression_buffer));
+	if (active_state->packet_compression) {
+		buffer_clear(&active_state->compression_buffer);
+		buffer_uncompress(&active_state->incoming_packet,
+		    &active_state->compression_buffer);
+		buffer_clear(&active_state->incoming_packet);
+		buffer_append(&active_state->incoming_packet,
+		    buffer_ptr(&active_state->compression_buffer),
+		    buffer_len(&active_state->compression_buffer));
 	}
-	p_read.packets++;
-	p_read.bytes += padded_len + 4;
-	type = buffer_get_char(&incoming_packet);
+	active_state->p_read.packets++;
+	active_state->p_read.bytes += padded_len + 4;
+	type = buffer_get_char(&active_state->incoming_packet);
 	if (type < SSH_MSG_MIN || type > SSH_MSG_MAX)
 		packet_disconnect("Invalid ssh1 packet type: %d", type);
 	return type;
@@ -1155,7 +1210,6 @@
 static int
 packet_read_poll2(u_int32_t *seqnr_p)
 {
-	static u_int packet_length = 0;
 	u_int padlen, need;
 	u_char *macbuf, *cp, type;
 	u_int maclen, block_size;
@@ -1163,50 +1217,52 @@
 	Mac *mac   = NULL;
 	Comp *comp = NULL;
 
-	if (packet_discard)
+	if (active_state->packet_discard)
 		return SSH_MSG_NONE;
 
-	if (newkeys[MODE_IN] != NULL) {
-		enc  = &newkeys[MODE_IN]->enc;
-		mac  = &newkeys[MODE_IN]->mac;
-		comp = &newkeys[MODE_IN]->comp;
+	if (active_state->newkeys[MODE_IN] != NULL) {
+		enc  = &active_state->newkeys[MODE_IN]->enc;
+		mac  = &active_state->newkeys[MODE_IN]->mac;
+		comp = &active_state->newkeys[MODE_IN]->comp;
 	}
 	maclen = mac && mac->enabled ? mac->mac_len : 0;
 	block_size = enc ? enc->block_size : 8;
 
-	if (packet_length == 0) {
+	if (active_state->packlen == 0) {
 		/*
 		 * check if input size is less than the cipher block size,
 		 * decrypt first block and extract length of incoming packet
 		 */
-		if (buffer_len(&input) < block_size)
+		if (buffer_len(&active_state->input) < block_size)
 			return SSH_MSG_NONE;
-		buffer_clear(&incoming_packet);
-		cp = buffer_append_space(&incoming_packet, block_size);
-		cipher_crypt(&receive_context, cp, buffer_ptr(&input),
+		buffer_clear(&active_state->incoming_packet);
+		cp = buffer_append_space(&active_state->incoming_packet,
 		    block_size);
-		cp = buffer_ptr(&incoming_packet);
-		packet_length = get_u32(cp);
-		if (packet_length < 1 + 4 || packet_length > PACKET_MAX_SIZE) {
+		cipher_crypt(&active_state->receive_context, cp,
+		    buffer_ptr(&active_state->input), block_size);
+		cp = buffer_ptr(&active_state->incoming_packet);
+		active_state->packlen = get_u32(cp);
+		if (active_state->packlen < 1 + 4 ||
+		    active_state->packlen > PACKET_MAX_SIZE) {
 #ifdef PACKET_DEBUG
-			buffer_dump(&incoming_packet);
+			buffer_dump(&active_state->incoming_packet);
 #endif
-			logit("Bad packet length %u.", packet_length);
-			packet_start_discard(enc, mac, packet_length,
+			logit("Bad packet length %u.", active_state->packlen);
+			packet_start_discard(enc, mac, active_state->packlen,
 			    PACKET_MAX_SIZE);
 			return SSH_MSG_NONE;
 		}
-		DBG(debug("input: packet len %u", packet_length+4));
-		buffer_consume(&input, block_size);
+		DBG(debug("input: packet len %u", active_state->packlen+4));
+		buffer_consume(&active_state->input, block_size);
 	}
 	/* we have a partial packet of block_size bytes */
-	need = 4 + packet_length - block_size;
+	need = 4 + active_state->packlen - block_size;
 	DBG(debug("partial packet %d, need %d, maclen %d", block_size,
 	    need, maclen));
 	if (need % block_size != 0) {
 		logit("padding error: need %d block %d mod %d",
 		    need, block_size, need % block_size);
-		packet_start_discard(enc, mac, packet_length,
+		packet_start_discard(enc, mac, active_state->packlen,
 		    PACKET_MAX_SIZE - block_size);
 		return SSH_MSG_NONE;
 	}
@@ -1214,84 +1270,90 @@
 	 * check if the entire packet has been received and
 	 * decrypt into incoming_packet
 	 */
-	if (buffer_len(&input) < need + maclen)
+	if (buffer_len(&active_state->input) < need + maclen)
 		return SSH_MSG_NONE;
 #ifdef PACKET_DEBUG
 	fprintf(stderr, "read_poll enc/full: ");
-	buffer_dump(&input);
+	buffer_dump(&active_state->input);
 #endif
-	cp = buffer_append_space(&incoming_packet, need);
-	cipher_crypt(&receive_context, cp, buffer_ptr(&input), need);
-	buffer_consume(&input, need);
+	cp = buffer_append_space(&active_state->incoming_packet, need);
+	cipher_crypt(&active_state->receive_context, cp,
+	    buffer_ptr(&active_state->input), need);
+	buffer_consume(&active_state->input, need);
 	/*
 	 * compute MAC over seqnr and packet,
 	 * increment sequence number for incoming packet
 	 */
 	if (mac && mac->enabled) {
-		macbuf = mac_compute(mac, p_read.seqnr,
-		    buffer_ptr(&incoming_packet),
-		    buffer_len(&incoming_packet));
-		if (memcmp(macbuf, buffer_ptr(&input), mac->mac_len) != 0) {
+		macbuf = mac_compute(mac, active_state->p_read.seqnr,
+		    buffer_ptr(&active_state->incoming_packet),
+		    buffer_len(&active_state->incoming_packet));
+		if (memcmp(macbuf, buffer_ptr(&active_state->input),
+		    mac->mac_len) != 0) {
 			logit("Corrupted MAC on input.");
 			if (need > PACKET_MAX_SIZE)
 				fatal("internal error need %d", need);
-			packet_start_discard(enc, mac, packet_length,
+			packet_start_discard(enc, mac, active_state->packlen,
 			    PACKET_MAX_SIZE - need);
 			return SSH_MSG_NONE;
 		}
 				
-		DBG(debug("MAC #%d ok", p_read.seqnr));
-		buffer_consume(&input, mac->mac_len);
+		DBG(debug("MAC #%d ok", active_state->p_read.seqnr));
+		buffer_consume(&active_state->input, mac->mac_len);
 	}
 	/* XXX now it's safe to use fatal/packet_disconnect */
 	if (seqnr_p != NULL)
-		*seqnr_p = p_read.seqnr;
-	if (++p_read.seqnr == 0)
+		*seqnr_p = active_state->p_read.seqnr;
+	if (++active_state->p_read.seqnr == 0)
 		logit("incoming seqnr wraps around");
-	if (++p_read.packets == 0)
+	if (++active_state->p_read.packets == 0)
 		if (!(datafellows & SSH_BUG_NOREKEY))
 			fatal("XXX too many packets with same key");
-	p_read.blocks += (packet_length + 4) / block_size;
-	p_read.bytes += packet_length + 4;
+	active_state->p_read.blocks += (active_state->packlen + 4) / block_size;
+	active_state->p_read.bytes += active_state->packlen + 4;
 
 	/* get padlen */
-	cp = buffer_ptr(&incoming_packet);
+	cp = buffer_ptr(&active_state->incoming_packet);
 	padlen = cp[4];
 	DBG(debug("input: padlen %d", padlen));
 	if (padlen < 4)
 		packet_disconnect("Corrupted padlen %d on input.", padlen);
 
 	/* skip packet size + padlen, discard padding */
-	buffer_consume(&incoming_packet, 4 + 1);
-	buffer_consume_end(&incoming_packet, padlen);
+	buffer_consume(&active_state->incoming_packet, 4 + 1);
+	buffer_consume_end(&active_state->incoming_packet, padlen);
 
-	DBG(debug("input: len before de-compress %d", buffer_len(&incoming_packet)));
+	DBG(debug("input: len before de-compress %d",
+	    buffer_len(&active_state->incoming_packet)));
 	if (comp && comp->enabled) {
-		buffer_clear(&compression_buffer);
-		buffer_uncompress(&incoming_packet, &compression_buffer);
-		buffer_clear(&incoming_packet);
-		buffer_append(&incoming_packet, buffer_ptr(&compression_buffer),
-		    buffer_len(&compression_buffer));
+		buffer_clear(&active_state->compression_buffer);
+		buffer_uncompress(&active_state->incoming_packet,
+		    &active_state->compression_buffer);
+		buffer_clear(&active_state->incoming_packet);
+		buffer_append(&active_state->incoming_packet,
+		    buffer_ptr(&active_state->compression_buffer),
+		    buffer_len(&active_state->compression_buffer));
 		DBG(debug("input: len after de-compress %d",
-		    buffer_len(&incoming_packet)));
+		    buffer_len(&active_state->incoming_packet)));
 	}
 	/*
 	 * get packet type, implies consume.
 	 * return length of payload (without type field)
 	 */
-	type = buffer_get_char(&incoming_packet);
+	type = buffer_get_char(&active_state->incoming_packet);
 	if (type < SSH2_MSG_MIN || type >= SSH2_MSG_LOCAL_MIN)
 		packet_disconnect("Invalid ssh2 packet type: %d", type);
 	if (type == SSH2_MSG_NEWKEYS)
 		set_newkeys(MODE_IN);
-	else if (type == SSH2_MSG_USERAUTH_SUCCESS && !server_side)
+	else if (type == SSH2_MSG_USERAUTH_SUCCESS &&
+	    !active_state->server_side)
 		packet_enable_delayed_compress();
 #ifdef PACKET_DEBUG
 	fprintf(stderr, "read/plain[%d]:\r\n", type);
-	buffer_dump(&incoming_packet);
+	buffer_dump(&active_state->incoming_packet);
 #endif
 	/* reset for next packet */
-	packet_length = 0;
+	active_state->packlen = 0;
 	return type;
 }
 
@@ -1306,7 +1368,7 @@
 		if (compat20) {
 			type = packet_read_poll2(seqnr_p);
 			if (type) {
-				keep_alive_timeouts = 0;
+				active_state->keep_alive_timeouts = 0;
 				DBG(debug("received packet type %d", type));
 			}
 			switch (type) {
@@ -1376,14 +1438,14 @@
 void
 packet_process_incoming(const char *buf, u_int len)
 {
-	if (packet_discard) {
-		keep_alive_timeouts = 0; /* ?? */
-		if (len >= packet_discard)
+	if (active_state->packet_discard) {
+		active_state->keep_alive_timeouts = 0; /* ?? */
+		if (len >= active_state->packet_discard)
 			packet_stop_discard();
-		packet_discard -= len;
+		active_state->packet_discard -= len;
 		return;
 	}
-	buffer_append(&input, buf, len);
+	buffer_append(&active_state->input, buf, len);
 }
 
 /* Returns a character from the packet. */
@@ -1393,7 +1455,7 @@
 {
 	char ch;
 
-	buffer_get(&incoming_packet, &ch, 1);
+	buffer_get(&active_state->incoming_packet, &ch, 1);
 	return (u_char) ch;
 }
 
@@ -1402,7 +1464,7 @@
 u_int
 packet_get_int(void)
 {
-	return buffer_get_int(&incoming_packet);
+	return buffer_get_int(&active_state->incoming_packet);
 }
 
 /*
@@ -1413,29 +1475,29 @@
 void
 packet_get_bignum(BIGNUM * value)
 {
-	buffer_get_bignum(&incoming_packet, value);
+	buffer_get_bignum(&active_state->incoming_packet, value);
 }
 
 void
 packet_get_bignum2(BIGNUM * value)
 {
-	buffer_get_bignum2(&incoming_packet, value);
+	buffer_get_bignum2(&active_state->incoming_packet, value);
 }
 
 void *
 packet_get_raw(u_int *length_ptr)
 {
-	u_int bytes = buffer_len(&incoming_packet);
+	u_int bytes = buffer_len(&active_state->incoming_packet);
 
 	if (length_ptr != NULL)
 		*length_ptr = bytes;
-	return buffer_ptr(&incoming_packet);
+	return buffer_ptr(&active_state->incoming_packet);
 }
 
 int
 packet_remaining(void)
 {
-	return buffer_len(&incoming_packet);
+	return buffer_len(&active_state->incoming_packet);
 }
 
 /*
@@ -1448,13 +1510,13 @@
 void *
 packet_get_string(u_int *length_ptr)
 {
-	return buffer_get_string(&incoming_packet, length_ptr);
+	return buffer_get_string(&active_state->incoming_packet, length_ptr);
 }
 
 void *
 packet_get_string_ptr(u_int *length_ptr)
 {
-	return buffer_get_string_ptr(&incoming_packet, length_ptr);
+	return buffer_get_string_ptr(&active_state->incoming_packet, length_ptr);
 }
 
 /*
@@ -1547,10 +1609,11 @@
 void
 packet_write_poll(void)
 {
-	int len = buffer_len(&output);
+	int len = buffer_len(&active_state->output);
 
 	if (len > 0) {
-		len = write(connection_out, buffer_ptr(&output), len);
+		len = write(active_state->connection_out,
+		    buffer_ptr(&active_state->output), len);
 		if (len == -1) {
 			if (errno == EINTR || errno == EAGAIN ||
 			    errno == EWOULDBLOCK)
@@ -1559,7 +1622,7 @@
 		}
 		if (len == 0)
 			fatal("Write connection closed");
-		buffer_consume(&output, len);
+		buffer_consume(&active_state->output, len);
 	}
 }
 
@@ -1576,30 +1639,30 @@
 	int ret, ms_remain;
 	struct timeval start, timeout, *timeoutp = NULL;
 
-	setp = (fd_set *)xcalloc(howmany(connection_out + 1, NFDBITS),
-	    sizeof(fd_mask));
+	setp = (fd_set *)xcalloc(howmany(active_state->connection_out + 1,
+	    NFDBITS), sizeof(fd_mask));
 	packet_write_poll();
 	while (packet_have_data_to_write()) {
-		memset(setp, 0, howmany(connection_out + 1, NFDBITS) *
-		    sizeof(fd_mask));
-		FD_SET(connection_out, setp);
+		memset(setp, 0, howmany(active_state->connection_out + 1,
+		    NFDBITS) * sizeof(fd_mask));
+		FD_SET(active_state->connection_out, setp);
 
-		if (packet_timeout_ms > 0) {
-			ms_remain = packet_timeout_ms;
+		if (active_state->packet_timeout_ms > 0) {
+			ms_remain = active_state->packet_timeout_ms;
 			timeoutp = &timeout;
 		}
 		for (;;) {
-			if (packet_timeout_ms != -1) {
+			if (active_state->packet_timeout_ms != -1) {
 				ms_to_timeval(&timeout, ms_remain);
 				gettimeofday(&start, NULL);
 			}
-			if ((ret = select(connection_out + 1, NULL, setp,
-			    NULL, timeoutp)) >= 0)
+			if ((ret = select(active_state->connection_out + 1,
+			    NULL, setp, NULL, timeoutp)) >= 0)
 				break;
-		   	if (errno != EAGAIN && errno != EINTR &&
+			if (errno != EAGAIN && errno != EINTR &&
 			    errno != EWOULDBLOCK)
 				break;
-			if (packet_timeout_ms == -1)
+			if (active_state->packet_timeout_ms == -1)
 				continue;
 			ms_subtract_diff(&start, &ms_remain);
 			if (ms_remain <= 0) {
@@ -1622,7 +1685,7 @@
 int
 packet_have_data_to_write(void)
 {
-	return buffer_len(&output) != 0;
+	return buffer_len(&active_state->output) != 0;
 }
 
 /* Returns true if there is not too much data to write to the connection. */
@@ -1630,10 +1693,10 @@
 int
 packet_not_very_much_data_to_write(void)
 {
-	if (interactive_mode)
-		return buffer_len(&output) < 16384;
+	if (active_state->interactive_mode)
+		return buffer_len(&active_state->output) < 16384;
 	else
-		return buffer_len(&output) < 128 * 1024;
+		return buffer_len(&active_state->output) < 128 * 1024;
 }
 
 
@@ -1646,7 +1709,7 @@
 	if (!packet_connection_is_on_socket() ||
 	    !packet_connection_is_ipv4())
 		return;
-	if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, &tos,
+	if (setsockopt(active_state->connection_in, IPPROTO_IP, IP_TOS, &tos,
 	    sizeof(tos)) < 0)
 		error("setsockopt IP_TOS %d: %.100s:",
 		    tos, strerror(errno));
@@ -1665,12 +1728,12 @@
 	called = 1;
 
 	/* Record that we are in interactive mode. */
-	interactive_mode = interactive;
+	active_state->interactive_mode = interactive;
 
 	/* Only set socket options if using a socket.  */
 	if (!packet_connection_is_on_socket())
 		return;
-	set_nodelay(connection_in);
+	set_nodelay(active_state->connection_in);
 	packet_set_tos(interactive);
 }
 
@@ -1679,7 +1742,7 @@
 int
 packet_is_interactive(void)
 {
-	return interactive_mode;
+	return active_state->interactive_mode;
 }
 
 int
@@ -1689,7 +1752,7 @@
 
 	if (called) {
 		logit("packet_set_maxsize: called twice: old %d new %d",
-		    max_packet_size, s);
+		    active_state->max_packet_size, s);
 		return -1;
 	}
 	if (s < 4 * 1024 || s > 1024 * 1024) {
@@ -1698,15 +1761,33 @@
 	}
 	called = 1;
 	debug("packet_set_maxsize: setting to %d", s);
-	max_packet_size = s;
+	active_state->max_packet_size = s;
 	return s;
 }
 
+int
+packet_inc_alive_timeouts(void)
+{
+	return ++active_state->keep_alive_timeouts;
+}
+
+void
+packet_set_alive_timeouts(int ka)
+{
+	active_state->keep_alive_timeouts = ka;
+}
+
+u_int
+packet_get_maxsize(void)
+{
+	return active_state->max_packet_size;
+}
+
 /* roundup current message to pad bytes */
 void
 packet_add_padding(u_char pad)
 {
-	extra_pad = pad;
+	active_state->extra_pad = pad;
 }
 
 /*
@@ -1743,26 +1824,46 @@
 	if (datafellows & SSH_BUG_NOREKEY)
 		return 0;
 	return
-	    (p_send.packets > MAX_PACKETS) ||
-	    (p_read.packets > MAX_PACKETS) ||
-	    (max_blocks_out && (p_send.blocks > max_blocks_out)) ||
-	    (max_blocks_in  && (p_read.blocks > max_blocks_in));
+	    (active_state->p_send.packets > MAX_PACKETS) ||
+	    (active_state->p_read.packets > MAX_PACKETS) ||
+	    (active_state->max_blocks_out &&
+	        (active_state->p_send.blocks > active_state->max_blocks_out)) ||
+	    (active_state->max_blocks_in &&
+	        (active_state->p_read.blocks > active_state->max_blocks_in));
 }
 
 void
 packet_set_rekey_limit(u_int32_t bytes)
 {
-	rekey_limit = bytes;
+	active_state->rekey_limit = bytes;
 }
 
 void
 packet_set_server(void)
 {
-	server_side = 1;
+	active_state->server_side = 1;
 }
 
 void
 packet_set_authenticated(void)
 {
-	after_authentication = 1;
+	active_state->after_authentication = 1;
+}
+
+void *
+packet_get_input(void)
+{
+	return (void *)&active_state->input;
+}
+
+void *
+packet_get_output(void)
+{
+	return (void *)&active_state->output;
+}
+
+void *
+packet_get_newkeys(int mode)
+{
+	return (void *)active_state->newkeys[mode];
 }