Adding upstream version 1:7.9p1.upstream/1%7.9p1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2682 insertions, 0 deletions

diff --git a/packet.c b/packet.c
new file mode 100644
index 0000000..dcf35e6
--- /dev/null
+++ b/packet.c
@@ -0,0 +1,2682 @@
+/* $OpenBSD: packet.c,v 1.277 2018/07/16 03:09:13 djm Exp $ */
+/*
+ * Author: Tatu Ylonen <ylo@cs.hut.fi>
+ * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
+ *                    All rights reserved
+ * This file contains code implementing the packet protocol and communication
+ * with the other side.  This same code is used both on client and server side.
+ *
+ * As far as I am concerned, the code I have written for this software
+ * can be used freely for any purpose.  Any derived versions of this
+ * software must be clearly marked as such, and if the derived work is
+ * incompatible with the protocol description in the RFC file, it must be
+ * called by a name other than "ssh" or "Secure Shell".
+ *
+ *
+ * SSH2 packet format added by Markus Friedl.
+ * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "includes.h"
+
+#include <sys/types.h>
+#include "openbsd-compat/sys-queue.h"
+#include <sys/socket.h>
+#ifdef HAVE_SYS_TIME_H
+# include <sys/time.h>
+#endif
+
+#include <netinet/in.h>
+#include <netinet/ip.h>
+#include <arpa/inet.h>
+
+#include <errno.h>
+#include <netdb.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <limits.h>
+#include <signal.h>
+#include <time.h>
+
+/*
+ * Explicitly include OpenSSL before zlib as some versions of OpenSSL have
+ * "free_func" in their headers, which zlib typedefs.
+ */
+#ifdef WITH_OPENSSL
+# include <openssl/bn.h>
+# include <openssl/evp.h>
+# ifdef OPENSSL_HAS_ECC
+#  include <openssl/ec.h>
+# endif
+#endif
+
+#include <zlib.h>
+
+#include "xmalloc.h"
+#include "crc32.h"
+#include "compat.h"
+#include "ssh2.h"
+#include "cipher.h"
+#include "sshkey.h"
+#include "kex.h"
+#include "digest.h"
+#include "mac.h"
+#include "log.h"
+#include "canohost.h"
+#include "misc.h"
+#include "channels.h"
+#include "ssh.h"
+#include "packet.h"
+#include "ssherr.h"
+#include "sshbuf.h"
+
+#ifdef PACKET_DEBUG
+#define DBG(x) x
+#else
+#define DBG(x)
+#endif
+
+#define PACKET_MAX_SIZE (256 * 1024)
+
+struct packet_state {
+	u_int32_t seqnr;
+	u_int32_t packets;
+	u_int64_t blocks;
+	u_int64_t bytes;
+};
+
+struct packet {
+	TAILQ_ENTRY(packet) next;
+	u_char type;
+	struct sshbuf *payload;
+};
+
+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. */
+	struct sshcipher_ctx *receive_context;
+
+	/* Encryption context for sending data.  Only used for encryption. */
+	struct sshcipher_ctx *send_context;
+
+	/* Buffer for raw input data from the socket. */
+	struct sshbuf *input;
+
+	/* Buffer for raw output data going to the socket. */
+	struct sshbuf *output;
+
+	/* Buffer for the partial outgoing packet being constructed. */
+	struct sshbuf *outgoing_packet;
+
+	/* Buffer for the incoming packet currently being processed. */
+	struct sshbuf *incoming_packet;
+
+	/* Scratch buffer for packet compression/decompression. */
+	struct sshbuf *compression_buffer;
+
+	/* Incoming/outgoing compression dictionaries */
+	z_stream compression_in_stream;
+	z_stream compression_out_stream;
+	int compression_in_started;
+	int compression_out_started;
+	int compression_in_failures;
+	int compression_out_failures;
+
+	/* 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 */
+	struct newkeys *newkeys[MODE_MAX];
+	struct packet_state p_read, p_send;
+
+	/* Volume-based rekeying */
+	u_int64_t max_blocks_in, max_blocks_out, rekey_limit;
+
+	/* Time-based rekeying */
+	u_int32_t rekey_interval;	/* how often in seconds */
+	time_t rekey_time;	/* time of last rekeying */
+
+	/* roundup current message to extra_pad bytes */
+	u_char extra_pad;
+
+	/* XXX discard incoming data after MAC error */
+	u_int packet_discard;
+	size_t packet_discard_mac_already;
+	struct sshmac *packet_discard_mac;
+
+	/* Used in packet_read_poll2() */
+	u_int packlen;
+
+	/* Used in packet_send2 */
+	int rekeying;
+
+	/* Used in ssh_packet_send_mux() */
+	int mux;
+
+	/* Used in packet_set_interactive */
+	int set_interactive_called;
+
+	/* Used in packet_set_maxsize */
+	int set_maxsize_called;
+
+	/* One-off warning about weak ciphers */
+	int cipher_warning_done;
+
+	/* Hook for fuzzing inbound packets */
+	ssh_packet_hook_fn *hook_in;
+	void *hook_in_ctx;
+
+	TAILQ_HEAD(, packet) outgoing;
+};
+
+struct ssh *
+ssh_alloc_session_state(void)
+{
+	struct ssh *ssh = NULL;
+	struct session_state *state = NULL;
+
+	if ((ssh = calloc(1, sizeof(*ssh))) == NULL ||
+	    (state = calloc(1, sizeof(*state))) == NULL ||
+	    (state->input = sshbuf_new()) == NULL ||
+	    (state->output = sshbuf_new()) == NULL ||
+	    (state->outgoing_packet = sshbuf_new()) == NULL ||
+	    (state->incoming_packet = sshbuf_new()) == NULL)
+		goto fail;
+	TAILQ_INIT(&state->outgoing);
+	TAILQ_INIT(&ssh->private_keys);
+	TAILQ_INIT(&ssh->public_keys);
+	state->connection_in = -1;
+	state->connection_out = -1;
+	state->max_packet_size = 32768;
+	state->packet_timeout_ms = -1;
+	state->p_send.packets = state->p_read.packets = 0;
+	state->initialized = 1;
+	/*
+	 * ssh_packet_send2() needs to queue packets until
+	 * we've done the initial key exchange.
+	 */
+	state->rekeying = 1;
+	ssh->state = state;
+	return ssh;
+ fail:
+	if (state) {
+		sshbuf_free(state->input);
+		sshbuf_free(state->output);
+		sshbuf_free(state->incoming_packet);
+		sshbuf_free(state->outgoing_packet);
+		free(state);
+	}
+	free(ssh);
+	return NULL;
+}
+
+void
+ssh_packet_set_input_hook(struct ssh *ssh, ssh_packet_hook_fn *hook, void *ctx)
+{
+	ssh->state->hook_in = hook;
+	ssh->state->hook_in_ctx = ctx;
+}
+
+/* Returns nonzero if rekeying is in progress */
+int
+ssh_packet_is_rekeying(struct ssh *ssh)
+{
+	return ssh->state->rekeying ||
+	    (ssh->kex != NULL && ssh->kex->done == 0);
+}
+
+/*
+ * Sets the descriptors used for communication.
+ */
+struct ssh *
+ssh_packet_set_connection(struct ssh *ssh, int fd_in, int fd_out)
+{
+	struct session_state *state;
+	const struct sshcipher *none = cipher_by_name("none");
+	int r;
+
+	if (none == NULL) {
+		error("%s: cannot load cipher 'none'", __func__);
+		return NULL;
+	}
+	if (ssh == NULL)
+		ssh = ssh_alloc_session_state();
+	if (ssh == NULL) {
+		error("%s: cound not allocate state", __func__);
+		return NULL;
+	}
+	state = ssh->state;
+	state->connection_in = fd_in;
+	state->connection_out = fd_out;
+	if ((r = cipher_init(&state->send_context, none,
+	    (const u_char *)"", 0, NULL, 0, CIPHER_ENCRYPT)) != 0 ||
+	    (r = cipher_init(&state->receive_context, none,
+	    (const u_char *)"", 0, NULL, 0, CIPHER_DECRYPT)) != 0) {
+		error("%s: cipher_init failed: %s", __func__, ssh_err(r));
+		free(ssh); /* XXX need ssh_free_session_state? */
+		return NULL;
+	}
+	state->newkeys[MODE_IN] = state->newkeys[MODE_OUT] = NULL;
+	/*
+	 * Cache the IP address of the remote connection for use in error
+	 * messages that might be generated after the connection has closed.
+	 */
+	(void)ssh_remote_ipaddr(ssh);
+	return ssh;
+}
+
+void
+ssh_packet_set_timeout(struct ssh *ssh, int timeout, int count)
+{
+	struct session_state *state = ssh->state;
+
+	if (timeout <= 0 || count <= 0) {
+		state->packet_timeout_ms = -1;
+		return;
+	}
+	if ((INT_MAX / 1000) / count < timeout)
+		state->packet_timeout_ms = INT_MAX;
+	else
+		state->packet_timeout_ms = timeout * count * 1000;
+}
+
+void
+ssh_packet_set_mux(struct ssh *ssh)
+{
+	ssh->state->mux = 1;
+	ssh->state->rekeying = 0;
+}
+
+int
+ssh_packet_get_mux(struct ssh *ssh)
+{
+	return ssh->state->mux;
+}
+
+int
+ssh_packet_set_log_preamble(struct ssh *ssh, const char *fmt, ...)
+{
+	va_list args;
+	int r;
+
+	free(ssh->log_preamble);
+	if (fmt == NULL)
+		ssh->log_preamble = NULL;
+	else {
+		va_start(args, fmt);
+		r = vasprintf(&ssh->log_preamble, fmt, args);
+		va_end(args);
+		if (r < 0 || ssh->log_preamble == NULL)
+			return SSH_ERR_ALLOC_FAIL;
+	}
+	return 0;
+}
+
+int
+ssh_packet_stop_discard(struct ssh *ssh)
+{
+	struct session_state *state = ssh->state;
+	int r;
+
+	if (state->packet_discard_mac) {
+		char buf[1024];
+		size_t dlen = PACKET_MAX_SIZE;
+
+		if (dlen > state->packet_discard_mac_already)
+			dlen -= state->packet_discard_mac_already;
+		memset(buf, 'a', sizeof(buf));
+		while (sshbuf_len(state->incoming_packet) < dlen)
+			if ((r = sshbuf_put(state->incoming_packet, buf,
+			    sizeof(buf))) != 0)
+				return r;
+		(void) mac_compute(state->packet_discard_mac,
+		    state->p_read.seqnr,
+		    sshbuf_ptr(state->incoming_packet), dlen,
+		    NULL, 0);
+	}
+	logit("Finished discarding for %.200s port %d",
+	    ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
+	return SSH_ERR_MAC_INVALID;
+}
+
+static int
+ssh_packet_start_discard(struct ssh *ssh, struct sshenc *enc,
+    struct sshmac *mac, size_t mac_already, u_int discard)
+{
+	struct session_state *state = ssh->state;
+	int r;
+
+	if (enc == NULL || !cipher_is_cbc(enc->cipher) || (mac && mac->etm)) {
+		if ((r = sshpkt_disconnect(ssh, "Packet corrupt")) != 0)
+			return r;
+		return SSH_ERR_MAC_INVALID;
+	}
+	/*
+	 * Record number of bytes over which the mac has already
+	 * been computed in order to minimize timing attacks.
+	 */
+	if (mac && mac->enabled) {
+		state->packet_discard_mac = mac;
+		state->packet_discard_mac_already = mac_already;
+	}
+	if (sshbuf_len(state->input) >= discard)
+		return ssh_packet_stop_discard(ssh);
+	state->packet_discard = discard - sshbuf_len(state->input);
+	return 0;
+}
+
+/* Returns 1 if remote host is connected via socket, 0 if not. */
+
+int
+ssh_packet_connection_is_on_socket(struct ssh *ssh)
+{
+	struct session_state *state;
+	struct sockaddr_storage from, to;
+	socklen_t fromlen, tolen;
+
+	if (ssh == NULL || ssh->state == NULL)
+		return 0;
+
+	state = ssh->state;
+	if (state->connection_in == -1 || state->connection_out == -1)
+		return 0;
+	/* filedescriptors in and out are the same, so it's a socket */
+	if (state->connection_in == state->connection_out)
+		return 1;
+	fromlen = sizeof(from);
+	memset(&from, 0, sizeof(from));
+	if (getpeername(state->connection_in, (struct sockaddr *)&from,
+	    &fromlen) < 0)
+		return 0;
+	tolen = sizeof(to);
+	memset(&to, 0, sizeof(to));
+	if (getpeername(state->connection_out, (struct sockaddr *)&to,
+	    &tolen) < 0)
+		return 0;
+	if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0)
+		return 0;
+	if (from.ss_family != AF_INET && from.ss_family != AF_INET6)
+		return 0;
+	return 1;
+}
+
+void
+ssh_packet_get_bytes(struct ssh *ssh, u_int64_t *ibytes, u_int64_t *obytes)
+{
+	if (ibytes)
+		*ibytes = ssh->state->p_read.bytes;
+	if (obytes)
+		*obytes = ssh->state->p_send.bytes;
+}
+
+int
+ssh_packet_connection_af(struct ssh *ssh)
+{
+	struct sockaddr_storage to;
+	socklen_t tolen = sizeof(to);
+
+	memset(&to, 0, sizeof(to));
+	if (getsockname(ssh->state->connection_out, (struct sockaddr *)&to,
+	    &tolen) < 0)
+		return 0;
+#ifdef IPV4_IN_IPV6
+	if (to.ss_family == AF_INET6 &&
+	    IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)&to)->sin6_addr))
+		return AF_INET;
+#endif
+	return to.ss_family;
+}
+
+/* Sets the connection into non-blocking mode. */
+
+void
+ssh_packet_set_nonblocking(struct ssh *ssh)
+{
+	/* Set the socket into non-blocking mode. */
+	set_nonblock(ssh->state->connection_in);
+
+	if (ssh->state->connection_out != ssh->state->connection_in)
+		set_nonblock(ssh->state->connection_out);
+}
+
+/* Returns the socket used for reading. */
+
+int
+ssh_packet_get_connection_in(struct ssh *ssh)
+{
+	return ssh->state->connection_in;
+}
+
+/* Returns the descriptor used for writing. */
+
+int
+ssh_packet_get_connection_out(struct ssh *ssh)
+{
+	return ssh->state->connection_out;
+}
+
+/*
+ * Returns the IP-address of the remote host as a string.  The returned
+ * string must not be freed.
+ */
+
+const char *
+ssh_remote_ipaddr(struct ssh *ssh)
+{
+	int sock;
+
+	/* Check whether we have cached the ipaddr. */
+	if (ssh->remote_ipaddr == NULL) {
+		if (ssh_packet_connection_is_on_socket(ssh)) {
+			sock = ssh->state->connection_in;
+			ssh->remote_ipaddr = get_peer_ipaddr(sock);
+			ssh->remote_port = get_peer_port(sock);
+			ssh->local_ipaddr = get_local_ipaddr(sock);
+			ssh->local_port = get_local_port(sock);
+		} else {
+			ssh->remote_ipaddr = strdup("UNKNOWN");
+			ssh->remote_port = 65535;
+			ssh->local_ipaddr = strdup("UNKNOWN");
+			ssh->local_port = 65535;
+		}
+	}
+	return ssh->remote_ipaddr;
+}
+
+/* Returns the port number of the remote host. */
+
+int
+ssh_remote_port(struct ssh *ssh)
+{
+	(void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */
+	return ssh->remote_port;
+}
+
+/*
+ * Returns the IP-address of the local host as a string.  The returned
+ * string must not be freed.
+ */
+
+const char *
+ssh_local_ipaddr(struct ssh *ssh)
+{
+	(void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */
+	return ssh->local_ipaddr;
+}
+
+/* Returns the port number of the local host. */
+
+int
+ssh_local_port(struct ssh *ssh)
+{
+	(void)ssh_remote_ipaddr(ssh); /* Will lookup and cache. */
+	return ssh->local_port;
+}
+
+/* Returns the routing domain of the input socket, or NULL if unavailable */
+const char *
+ssh_packet_rdomain_in(struct ssh *ssh)
+{
+	if (ssh->rdomain_in != NULL)
+		return ssh->rdomain_in;
+	if (!ssh_packet_connection_is_on_socket(ssh))
+		return NULL;
+	ssh->rdomain_in = get_rdomain(ssh->state->connection_in);
+	return ssh->rdomain_in;
+}
+
+/* Closes the connection and clears and frees internal data structures. */
+
+static void
+ssh_packet_close_internal(struct ssh *ssh, int do_close)
+{
+	struct session_state *state = ssh->state;
+	u_int mode;
+
+	if (!state->initialized)
+		return;
+	state->initialized = 0;
+	if (do_close) {
+		if (state->connection_in == state->connection_out) {
+			close(state->connection_out);
+		} else {
+			close(state->connection_in);
+			close(state->connection_out);
+		}
+	}
+	sshbuf_free(state->input);
+	sshbuf_free(state->output);
+	sshbuf_free(state->outgoing_packet);
+	sshbuf_free(state->incoming_packet);
+	for (mode = 0; mode < MODE_MAX; mode++) {
+		kex_free_newkeys(state->newkeys[mode]);	/* current keys */
+		state->newkeys[mode] = NULL;
+		ssh_clear_newkeys(ssh, mode);		/* next keys */
+	}
+	/* compression state is in shared mem, so we can only release it once */
+	if (do_close && state->compression_buffer) {
+		sshbuf_free(state->compression_buffer);
+		if (state->compression_out_started) {
+			z_streamp stream = &state->compression_out_stream;
+			debug("compress outgoing: "
+			    "raw data %llu, compressed %llu, factor %.2f",
+				(unsigned long long)stream->total_in,
+				(unsigned long long)stream->total_out,
+				stream->total_in == 0 ? 0.0 :
+				(double) stream->total_out / stream->total_in);
+			if (state->compression_out_failures == 0)
+				deflateEnd(stream);
+		}
+		if (state->compression_in_started) {
+			z_streamp stream = &state->compression_in_stream;
+			debug("compress incoming: "
+			    "raw data %llu, compressed %llu, factor %.2f",
+			    (unsigned long long)stream->total_out,
+			    (unsigned long long)stream->total_in,
+			    stream->total_out == 0 ? 0.0 :
+			    (double) stream->total_in / stream->total_out);
+			if (state->compression_in_failures == 0)
+				inflateEnd(stream);
+		}
+	}
+	cipher_free(state->send_context);
+	cipher_free(state->receive_context);
+	state->send_context = state->receive_context = NULL;
+	if (do_close) {
+		free(ssh->local_ipaddr);
+		ssh->local_ipaddr = NULL;
+		free(ssh->remote_ipaddr);
+		ssh->remote_ipaddr = NULL;
+		free(ssh->state);
+		ssh->state = NULL;
+	}
+}
+
+void
+ssh_packet_close(struct ssh *ssh)
+{
+	ssh_packet_close_internal(ssh, 1);
+}
+
+void
+ssh_packet_clear_keys(struct ssh *ssh)
+{
+	ssh_packet_close_internal(ssh, 0);
+}
+
+/* Sets remote side protocol flags. */
+
+void
+ssh_packet_set_protocol_flags(struct ssh *ssh, u_int protocol_flags)
+{
+	ssh->state->remote_protocol_flags = protocol_flags;
+}
+
+/* Returns the remote protocol flags set earlier by the above function. */
+
+u_int
+ssh_packet_get_protocol_flags(struct ssh *ssh)
+{
+	return ssh->state->remote_protocol_flags;
+}
+
+/*
+ * Starts packet compression from the next packet on in both directions.
+ * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip.
+ */
+
+static int
+ssh_packet_init_compression(struct ssh *ssh)
+{
+	if (!ssh->state->compression_buffer &&
+	   ((ssh->state->compression_buffer = sshbuf_new()) == NULL))
+		return SSH_ERR_ALLOC_FAIL;
+	return 0;
+}
+
+static int
+start_compression_out(struct ssh *ssh, int level)
+{
+	if (level < 1 || level > 9)
+		return SSH_ERR_INVALID_ARGUMENT;
+	debug("Enabling compression at level %d.", level);
+	if (ssh->state->compression_out_started == 1)
+		deflateEnd(&ssh->state->compression_out_stream);
+	switch (deflateInit(&ssh->state->compression_out_stream, level)) {
+	case Z_OK:
+		ssh->state->compression_out_started = 1;
+		break;
+	case Z_MEM_ERROR:
+		return SSH_ERR_ALLOC_FAIL;
+	default:
+		return SSH_ERR_INTERNAL_ERROR;
+	}
+	return 0;
+}
+
+static int
+start_compression_in(struct ssh *ssh)
+{
+	if (ssh->state->compression_in_started == 1)
+		inflateEnd(&ssh->state->compression_in_stream);
+	switch (inflateInit(&ssh->state->compression_in_stream)) {
+	case Z_OK:
+		ssh->state->compression_in_started = 1;
+		break;
+	case Z_MEM_ERROR:
+		return SSH_ERR_ALLOC_FAIL;
+	default:
+		return SSH_ERR_INTERNAL_ERROR;
+	}
+	return 0;
+}
+
+/* XXX remove need for separate compression buffer */
+static int
+compress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out)
+{
+	u_char buf[4096];
+	int r, status;
+
+	if (ssh->state->compression_out_started != 1)
+		return SSH_ERR_INTERNAL_ERROR;
+
+	/* This case is not handled below. */
+	if (sshbuf_len(in) == 0)
+		return 0;
+
+	/* Input is the contents of the input buffer. */
+	if ((ssh->state->compression_out_stream.next_in =
+	    sshbuf_mutable_ptr(in)) == NULL)
+		return SSH_ERR_INTERNAL_ERROR;
+	ssh->state->compression_out_stream.avail_in = sshbuf_len(in);
+
+	/* Loop compressing until deflate() returns with avail_out != 0. */
+	do {
+		/* Set up fixed-size output buffer. */
+		ssh->state->compression_out_stream.next_out = buf;
+		ssh->state->compression_out_stream.avail_out = sizeof(buf);
+
+		/* Compress as much data into the buffer as possible. */
+		status = deflate(&ssh->state->compression_out_stream,
+		    Z_PARTIAL_FLUSH);
+		switch (status) {
+		case Z_MEM_ERROR:
+			return SSH_ERR_ALLOC_FAIL;
+		case Z_OK:
+			/* Append compressed data to output_buffer. */
+			if ((r = sshbuf_put(out, buf, sizeof(buf) -
+			    ssh->state->compression_out_stream.avail_out)) != 0)
+				return r;
+			break;
+		case Z_STREAM_ERROR:
+		default:
+			ssh->state->compression_out_failures++;
+			return SSH_ERR_INVALID_FORMAT;
+		}
+	} while (ssh->state->compression_out_stream.avail_out == 0);
+	return 0;
+}
+
+static int
+uncompress_buffer(struct ssh *ssh, struct sshbuf *in, struct sshbuf *out)
+{
+	u_char buf[4096];
+	int r, status;
+
+	if (ssh->state->compression_in_started != 1)
+		return SSH_ERR_INTERNAL_ERROR;
+
+	if ((ssh->state->compression_in_stream.next_in =
+	    sshbuf_mutable_ptr(in)) == NULL)
+		return SSH_ERR_INTERNAL_ERROR;
+	ssh->state->compression_in_stream.avail_in = sshbuf_len(in);
+
+	for (;;) {
+		/* Set up fixed-size output buffer. */
+		ssh->state->compression_in_stream.next_out = buf;
+		ssh->state->compression_in_stream.avail_out = sizeof(buf);
+
+		status = inflate(&ssh->state->compression_in_stream,
+		    Z_PARTIAL_FLUSH);
+		switch (status) {
+		case Z_OK:
+			if ((r = sshbuf_put(out, buf, sizeof(buf) -
+			    ssh->state->compression_in_stream.avail_out)) != 0)
+				return r;
+			break;
+		case Z_BUF_ERROR:
+			/*
+			 * Comments in zlib.h say that we should keep calling
+			 * inflate() until we get an error.  This appears to
+			 * be the error that we get.
+			 */
+			return 0;
+		case Z_DATA_ERROR:
+			return SSH_ERR_INVALID_FORMAT;
+		case Z_MEM_ERROR:
+			return SSH_ERR_ALLOC_FAIL;
+		case Z_STREAM_ERROR:
+		default:
+			ssh->state->compression_in_failures++;
+			return SSH_ERR_INTERNAL_ERROR;
+		}
+	}
+	/* NOTREACHED */
+}
+
+void
+ssh_clear_newkeys(struct ssh *ssh, int mode)
+{
+	if (ssh->kex && ssh->kex->newkeys[mode]) {
+		kex_free_newkeys(ssh->kex->newkeys[mode]);
+		ssh->kex->newkeys[mode] = NULL;
+	}
+}
+
+int
+ssh_set_newkeys(struct ssh *ssh, int mode)
+{
+	struct session_state *state = ssh->state;
+	struct sshenc *enc;
+	struct sshmac *mac;
+	struct sshcomp *comp;
+	struct sshcipher_ctx **ccp;
+	struct packet_state *ps;
+	u_int64_t *max_blocks;
+	const char *wmsg;
+	int r, crypt_type;
+
+	debug2("set_newkeys: mode %d", mode);
+
+	if (mode == MODE_OUT) {
+		ccp = &state->send_context;
+		crypt_type = CIPHER_ENCRYPT;
+		ps = &state->p_send;
+		max_blocks = &state->max_blocks_out;
+	} else {
+		ccp = &state->receive_context;
+		crypt_type = CIPHER_DECRYPT;
+		ps = &state->p_read;
+		max_blocks = &state->max_blocks_in;
+	}
+	if (state->newkeys[mode] != NULL) {
+		debug("set_newkeys: rekeying, input %llu bytes %llu blocks, "
+		   "output %llu bytes %llu blocks",
+		   (unsigned long long)state->p_read.bytes,
+		   (unsigned long long)state->p_read.blocks,
+		   (unsigned long long)state->p_send.bytes,
+		   (unsigned long long)state->p_send.blocks);
+		cipher_free(*ccp);
+		*ccp = NULL;
+		kex_free_newkeys(state->newkeys[mode]);
+		state->newkeys[mode] = NULL;
+	}
+	/* note that both bytes and the seqnr are not reset */
+	ps->packets = ps->blocks = 0;
+	/* move newkeys from kex to state */
+	if ((state->newkeys[mode] = ssh->kex->newkeys[mode]) == NULL)
+		return SSH_ERR_INTERNAL_ERROR;
+	ssh->kex->newkeys[mode] = NULL;
+	enc  = &state->newkeys[mode]->enc;
+	mac  = &state->newkeys[mode]->mac;
+	comp = &state->newkeys[mode]->comp;
+	if (cipher_authlen(enc->cipher) == 0) {
+		if ((r = mac_init(mac)) != 0)
+			return r;
+	}
+	mac->enabled = 1;
+	DBG(debug("cipher_init_context: %d", mode));
+	if ((r = cipher_init(ccp, enc->cipher, enc->key, enc->key_len,
+	    enc->iv, enc->iv_len, crypt_type)) != 0)
+		return r;
+	if (!state->cipher_warning_done &&
+	    (wmsg = cipher_warning_message(*ccp)) != NULL) {
+		error("Warning: %s", wmsg);
+		state->cipher_warning_done = 1;
+	}
+	/* Deleting the keys does not gain extra security */
+	/* explicit_bzero(enc->iv,  enc->block_size);
+	   explicit_bzero(enc->key, enc->key_len);
+	   explicit_bzero(mac->key, mac->key_len); */
+	if ((comp->type == COMP_ZLIB ||
+	    (comp->type == COMP_DELAYED &&
+	     state->after_authentication)) && comp->enabled == 0) {
+		if ((r = ssh_packet_init_compression(ssh)) < 0)
+			return r;
+		if (mode == MODE_OUT) {
+			if ((r = start_compression_out(ssh, 6)) != 0)
+				return r;
+		} else {
+			if ((r = start_compression_in(ssh)) != 0)
+				return r;
+		}
+		comp->enabled = 1;
+	}
+	/*
+	 * The 2^(blocksize*2) limit is too expensive for 3DES,
+	 * so enforce a 1GB limit for small blocksizes.
+	 * See RFC4344 section 3.2.
+	 */
+	if (enc->block_size >= 16)
+		*max_blocks = (u_int64_t)1 << (enc->block_size*2);
+	else
+		*max_blocks = ((u_int64_t)1 << 30) / enc->block_size;
+	if (state->rekey_limit)
+		*max_blocks = MINIMUM(*max_blocks,
+		    state->rekey_limit / enc->block_size);
+	debug("rekey after %llu blocks", (unsigned long long)*max_blocks);
+	return 0;
+}
+
+#define MAX_PACKETS	(1U<<31)
+static int
+ssh_packet_need_rekeying(struct ssh *ssh, u_int outbound_packet_len)
+{
+	struct session_state *state = ssh->state;
+	u_int32_t out_blocks;
+
+	/* XXX client can't cope with rekeying pre-auth */
+	if (!state->after_authentication)
+		return 0;
+
+	/* Haven't keyed yet or KEX in progress. */
+	if (ssh->kex == NULL || ssh_packet_is_rekeying(ssh))
+		return 0;
+
+	/* Peer can't rekey */
+	if (ssh->compat & SSH_BUG_NOREKEY)
+		return 0;
+
+	/*
+	 * Permit one packet in or out per rekey - this allows us to
+	 * make progress when rekey limits are very small.
+	 */
+	if (state->p_send.packets == 0 && state->p_read.packets == 0)
+		return 0;
+
+	/* Time-based rekeying */
+	if (state->rekey_interval != 0 &&
+	    (int64_t)state->rekey_time + state->rekey_interval <= monotime())
+		return 1;
+
+	/*
+	 * Always rekey when MAX_PACKETS sent in either direction 
+	 * As per RFC4344 section 3.1 we do this after 2^31 packets.
+	 */
+	if (state->p_send.packets > MAX_PACKETS ||
+	    state->p_read.packets > MAX_PACKETS)
+		return 1;
+
+	/* Rekey after (cipher-specific) maximum blocks */
+	out_blocks = ROUNDUP(outbound_packet_len,
+	    state->newkeys[MODE_OUT]->enc.block_size);
+	return (state->max_blocks_out &&
+	    (state->p_send.blocks + out_blocks > state->max_blocks_out)) ||
+	    (state->max_blocks_in &&
+	    (state->p_read.blocks > state->max_blocks_in));
+}
+
+/*
+ * Delayed compression for SSH2 is enabled after authentication:
+ * This happens on the server side after a SSH2_MSG_USERAUTH_SUCCESS is sent,
+ * and on the client side after a SSH2_MSG_USERAUTH_SUCCESS is received.
+ */
+static int
+ssh_packet_enable_delayed_compress(struct ssh *ssh)
+{
+	struct session_state *state = ssh->state;
+	struct sshcomp *comp = NULL;
+	int r, mode;
+
+	/*
+	 * Remember that we are past the authentication step, so rekeying
+	 * with COMP_DELAYED will turn on compression immediately.
+	 */
+	state->after_authentication = 1;
+	for (mode = 0; mode < MODE_MAX; mode++) {
+		/* protocol error: USERAUTH_SUCCESS received before NEWKEYS */
+		if (state->newkeys[mode] == NULL)
+			continue;
+		comp = &state->newkeys[mode]->comp;
+		if (comp && !comp->enabled && comp->type == COMP_DELAYED) {
+			if ((r = ssh_packet_init_compression(ssh)) != 0)
+				return r;
+			if (mode == MODE_OUT) {
+				if ((r = start_compression_out(ssh, 6)) != 0)
+					return r;
+			} else {
+				if ((r = start_compression_in(ssh)) != 0)
+					return r;
+			}
+			comp->enabled = 1;
+		}
+	}
+	return 0;
+}
+
+/* Used to mute debug logging for noisy packet types */
+int
+ssh_packet_log_type(u_char type)
+{
+	switch (type) {
+	case SSH2_MSG_CHANNEL_DATA:
+	case SSH2_MSG_CHANNEL_EXTENDED_DATA:
+	case SSH2_MSG_CHANNEL_WINDOW_ADJUST:
+		return 0;
+	default:
+		return 1;
+	}
+}
+
+/*
+ * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue)
+ */
+int
+ssh_packet_send2_wrapped(struct ssh *ssh)
+{
+	struct session_state *state = ssh->state;
+	u_char type, *cp, macbuf[SSH_DIGEST_MAX_LENGTH];
+	u_char tmp, padlen, pad = 0;
+	u_int authlen = 0, aadlen = 0;
+	u_int len;
+	struct sshenc *enc   = NULL;
+	struct sshmac *mac   = NULL;
+	struct sshcomp *comp = NULL;
+	int r, block_size;
+
+	if (state->newkeys[MODE_OUT] != NULL) {
+		enc  = &state->newkeys[MODE_OUT]->enc;
+		mac  = &state->newkeys[MODE_OUT]->mac;
+		comp = &state->newkeys[MODE_OUT]->comp;
+		/* disable mac for authenticated encryption */
+		if ((authlen = cipher_authlen(enc->cipher)) != 0)
+			mac = NULL;
+	}
+	block_size = enc ? enc->block_size : 8;
+	aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0;
+
+	type = (sshbuf_ptr(state->outgoing_packet))[5];
+	if (ssh_packet_log_type(type))
+		debug3("send packet: type %u", type);
+#ifdef PACKET_DEBUG
+	fprintf(stderr, "plain:     ");
+	sshbuf_dump(state->outgoing_packet, stderr);
+#endif
+
+	if (comp && comp->enabled) {
+		len = sshbuf_len(state->outgoing_packet);
+		/* skip header, compress only payload */
+		if ((r = sshbuf_consume(state->outgoing_packet, 5)) != 0)
+			goto out;
+		sshbuf_reset(state->compression_buffer);
+		if ((r = compress_buffer(ssh, state->outgoing_packet,
+		    state->compression_buffer)) != 0)
+			goto out;
+		sshbuf_reset(state->outgoing_packet);
+		if ((r = sshbuf_put(state->outgoing_packet,
+		    "\0\0\0\0\0", 5)) != 0 ||
+		    (r = sshbuf_putb(state->outgoing_packet,
+		    state->compression_buffer)) != 0)
+			goto out;
+		DBG(debug("compression: raw %d compressed %zd", len,
+		    sshbuf_len(state->outgoing_packet)));
+	}
+
+	/* sizeof (packet_len + pad_len + payload) */
+	len = sshbuf_len(state->outgoing_packet);
+
+	/*
+	 * calc size of padding, alloc space, get random data,
+	 * minimum padding is 4 bytes
+	 */
+	len -= aadlen; /* packet length is not encrypted for EtM modes */
+	padlen = block_size - (len % block_size);
+	if (padlen < 4)
+		padlen += block_size;
+	if (state->extra_pad) {
+		tmp = state->extra_pad;
+		state->extra_pad =
+		    ROUNDUP(state->extra_pad, block_size);
+		/* check if roundup overflowed */
+		if (state->extra_pad < tmp)
+			return SSH_ERR_INVALID_ARGUMENT;
+		tmp = (len + padlen) % state->extra_pad;
+		/* Check whether pad calculation below will underflow */
+		if (tmp > state->extra_pad)
+			return SSH_ERR_INVALID_ARGUMENT;
+		pad = state->extra_pad - tmp;
+		DBG(debug3("%s: adding %d (len %d padlen %d extra_pad %d)",
+		    __func__, pad, len, padlen, state->extra_pad));
+		tmp = padlen;
+		padlen += pad;
+		/* Check whether padlen calculation overflowed */
+		if (padlen < tmp)
+			return SSH_ERR_INVALID_ARGUMENT; /* overflow */
+		state->extra_pad = 0;
+	}
+	if ((r = sshbuf_reserve(state->outgoing_packet, padlen, &cp)) != 0)
+		goto out;
+	if (enc && !cipher_ctx_is_plaintext(state->send_context)) {
+		/* random padding */
+		arc4random_buf(cp, padlen);
+	} else {
+		/* clear padding */
+		explicit_bzero(cp, padlen);
+	}
+	/* sizeof (packet_len + pad_len + payload + padding) */
+	len = sshbuf_len(state->outgoing_packet);
+	cp = sshbuf_mutable_ptr(state->outgoing_packet);
+	if (cp == NULL) {
+		r = SSH_ERR_INTERNAL_ERROR;
+		goto out;
+	}
+	/* packet_length includes payload, padding and padding length field */
+	POKE_U32(cp, len - 4);
+	cp[4] = padlen;
+	DBG(debug("send: len %d (includes padlen %d, aadlen %d)",
+	    len, padlen, aadlen));
+
+	/* compute MAC over seqnr and packet(length fields, payload, padding) */
+	if (mac && mac->enabled && !mac->etm) {
+		if ((r = mac_compute(mac, state->p_send.seqnr,
+		    sshbuf_ptr(state->outgoing_packet), len,
+		    macbuf, sizeof(macbuf))) != 0)
+			goto out;
+		DBG(debug("done calc MAC out #%d", state->p_send.seqnr));
+	}
+	/* encrypt packet and append to output buffer. */
+	if ((r = sshbuf_reserve(state->output,
+	    sshbuf_len(state->outgoing_packet) + authlen, &cp)) != 0)
+		goto out;
+	if ((r = cipher_crypt(state->send_context, state->p_send.seqnr, cp,
+	    sshbuf_ptr(state->outgoing_packet),
+	    len - aadlen, aadlen, authlen)) != 0)
+		goto out;
+	/* append unencrypted MAC */
+	if (mac && mac->enabled) {
+		if (mac->etm) {
+			/* EtM: compute mac over aadlen + cipher text */
+			if ((r = mac_compute(mac, state->p_send.seqnr,
+			    cp, len, macbuf, sizeof(macbuf))) != 0)
+				goto out;
+			DBG(debug("done calc MAC(EtM) out #%d",
+			    state->p_send.seqnr));
+		}
+		if ((r = sshbuf_put(state->output, macbuf, mac->mac_len)) != 0)
+			goto out;
+	}
+#ifdef PACKET_DEBUG
+	fprintf(stderr, "encrypted: ");
+	sshbuf_dump(state->output, stderr);
+#endif
+	/* increment sequence number for outgoing packets */
+	if (++state->p_send.seqnr == 0)
+		logit("outgoing seqnr wraps around");
+	if (++state->p_send.packets == 0)
+		if (!(ssh->compat & SSH_BUG_NOREKEY))
+			return SSH_ERR_NEED_REKEY;
+	state->p_send.blocks += len / block_size;
+	state->p_send.bytes += len;
+	sshbuf_reset(state->outgoing_packet);
+
+	if (type == SSH2_MSG_NEWKEYS)
+		r = ssh_set_newkeys(ssh, MODE_OUT);
+	else if (type == SSH2_MSG_USERAUTH_SUCCESS && state->server_side)
+		r = ssh_packet_enable_delayed_compress(ssh);
+	else
+		r = 0;
+ out:
+	return r;
+}
+
+/* returns non-zero if the specified packet type is usec by KEX */
+static int
+ssh_packet_type_is_kex(u_char type)
+{
+	return
+	    type >= SSH2_MSG_TRANSPORT_MIN &&
+	    type <= SSH2_MSG_TRANSPORT_MAX &&
+	    type != SSH2_MSG_SERVICE_REQUEST &&
+	    type != SSH2_MSG_SERVICE_ACCEPT &&
+	    type != SSH2_MSG_EXT_INFO;
+}
+
+int
+ssh_packet_send2(struct ssh *ssh)
+{
+	struct session_state *state = ssh->state;
+	struct packet *p;
+	u_char type;
+	int r, need_rekey;
+
+	if (sshbuf_len(state->outgoing_packet) < 6)
+		return SSH_ERR_INTERNAL_ERROR;
+	type = sshbuf_ptr(state->outgoing_packet)[5];
+	need_rekey = !ssh_packet_type_is_kex(type) &&
+	    ssh_packet_need_rekeying(ssh, sshbuf_len(state->outgoing_packet));
+
+	/*
+	 * During rekeying we can only send key exchange messages.
+	 * Queue everything else.
+	 */
+	if ((need_rekey || state->rekeying) && !ssh_packet_type_is_kex(type)) {
+		if (need_rekey)
+			debug3("%s: rekex triggered", __func__);
+		debug("enqueue packet: %u", type);
+		p = calloc(1, sizeof(*p));
+		if (p == NULL)
+			return SSH_ERR_ALLOC_FAIL;
+		p->type = type;
+		p->payload = state->outgoing_packet;
+		TAILQ_INSERT_TAIL(&state->outgoing, p, next);
+		state->outgoing_packet = sshbuf_new();
+		if (state->outgoing_packet == NULL)
+			return SSH_ERR_ALLOC_FAIL;
+		if (need_rekey) {
+			/*
+			 * This packet triggered a rekey, so send the
+			 * KEXINIT now.
+			 * NB. reenters this function via kex_start_rekex().
+			 */
+			return kex_start_rekex(ssh);
+		}
+		return 0;
+	}
+
+	/* rekeying starts with sending KEXINIT */
+	if (type == SSH2_MSG_KEXINIT)
+		state->rekeying = 1;
+
+	if ((r = ssh_packet_send2_wrapped(ssh)) != 0)
+		return r;
+
+	/* after a NEWKEYS message we can send the complete queue */
+	if (type == SSH2_MSG_NEWKEYS) {
+		state->rekeying = 0;
+		state->rekey_time = monotime();
+		while ((p = TAILQ_FIRST(&state->outgoing))) {
+			type = p->type;
+			/*
+			 * If this packet triggers a rekex, then skip the
+			 * remaining packets in the queue for now.
+			 * NB. re-enters this function via kex_start_rekex.
+			 */
+			if (ssh_packet_need_rekeying(ssh,
+			    sshbuf_len(p->payload))) {
+				debug3("%s: queued packet triggered rekex",
+				    __func__);
+				return kex_start_rekex(ssh);
+			}
+			debug("dequeue packet: %u", type);
+			sshbuf_free(state->outgoing_packet);
+			state->outgoing_packet = p->payload;
+			TAILQ_REMOVE(&state->outgoing, p, next);
+			memset(p, 0, sizeof(*p));
+			free(p);
+			if ((r = ssh_packet_send2_wrapped(ssh)) != 0)
+				return r;
+		}
+	}
+	return 0;
+}
+
+/*
+ * Waits until a packet has been received, and returns its type.  Note that
+ * no other data is processed until this returns, so this function should not
+ * be used during the interactive session.
+ */
+
+int
+ssh_packet_read_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
+{
+	struct session_state *state = ssh->state;
+	int len, r, ms_remain;
+	fd_set *setp;
+	char buf[8192];
+	struct timeval timeout, start, *timeoutp = NULL;
+
+	DBG(debug("packet_read()"));
+
+	setp = calloc(howmany(state->connection_in + 1,
+	    NFDBITS), sizeof(fd_mask));
+	if (setp == NULL)
+		return SSH_ERR_ALLOC_FAIL;
+
+	/*
+	 * Since we are blocking, ensure that all written packets have
+	 * been sent.
+	 */
+	if ((r = ssh_packet_write_wait(ssh)) != 0)
+		goto out;
+
+	/* Stay in the loop until we have received a complete packet. */
+	for (;;) {
+		/* Try to read a packet from the buffer. */
+		r = ssh_packet_read_poll_seqnr(ssh, typep, seqnr_p);
+		if (r != 0)
+			break;
+		/* If we got a packet, return it. */
+		if (*typep != SSH_MSG_NONE)
+			break;
+		/*
+		 * Otherwise, wait for some data to arrive, add it to the
+		 * buffer, and try again.
+		 */
+		memset(setp, 0, howmany(state->connection_in + 1,
+		    NFDBITS) * sizeof(fd_mask));
+		FD_SET(state->connection_in, setp);
+
+		if (state->packet_timeout_ms > 0) {
+			ms_remain = state->packet_timeout_ms;
+			timeoutp = &timeout;
+		}
+		/* Wait for some data to arrive. */
+		for (;;) {
+			if (state->packet_timeout_ms != -1) {
+				ms_to_timeval(&timeout, ms_remain);
+				monotime_tv(&start);
+			}
+			if ((r = select(state->connection_in + 1, setp,
+			    NULL, NULL, timeoutp)) >= 0)
+				break;
+			if (errno != EAGAIN && errno != EINTR &&
+			    errno != EWOULDBLOCK) {
+				r = SSH_ERR_SYSTEM_ERROR;
+				goto out;
+			}
+			if (state->packet_timeout_ms == -1)
+				continue;
+			ms_subtract_diff(&start, &ms_remain);
+			if (ms_remain <= 0) {
+				r = 0;
+				break;
+			}
+		}
+		if (r == 0) {
+			r = SSH_ERR_CONN_TIMEOUT;
+			goto out;
+		}
+		/* Read data from the socket. */
+		len = read(state->connection_in, buf, sizeof(buf));
+		if (len == 0) {
+			r = SSH_ERR_CONN_CLOSED;
+			goto out;
+		}
+		if (len < 0) {
+			r = SSH_ERR_SYSTEM_ERROR;
+			goto out;
+		}
+
+		/* Append it to the buffer. */
+		if ((r = ssh_packet_process_incoming(ssh, buf, len)) != 0)
+			goto out;
+	}
+ out:
+	free(setp);
+	return r;
+}
+
+int
+ssh_packet_read(struct ssh *ssh)
+{
+	u_char type;
+	int r;
+
+	if ((r = ssh_packet_read_seqnr(ssh, &type, NULL)) != 0)
+		fatal("%s: %s", __func__, ssh_err(r));
+	return type;
+}
+
+/*
+ * Waits until a packet has been received, verifies that its type matches
+ * that given, and gives a fatal error and exits if there is a mismatch.
+ */
+
+int
+ssh_packet_read_expect(struct ssh *ssh, u_int expected_type)
+{
+	int r;
+	u_char type;
+
+	if ((r = ssh_packet_read_seqnr(ssh, &type, NULL)) != 0)
+		return r;
+	if (type != expected_type) {
+		if ((r = sshpkt_disconnect(ssh,
+		    "Protocol error: expected packet type %d, got %d",
+		    expected_type, type)) != 0)
+			return r;
+		return SSH_ERR_PROTOCOL_ERROR;
+	}
+	return 0;
+}
+
+static int
+ssh_packet_read_poll2_mux(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
+{
+	struct session_state *state = ssh->state;
+	const u_char *cp;
+	size_t need;
+	int r;
+
+	if (ssh->kex)
+		return SSH_ERR_INTERNAL_ERROR;
+	*typep = SSH_MSG_NONE;
+	cp = sshbuf_ptr(state->input);
+	if (state->packlen == 0) {
+		if (sshbuf_len(state->input) < 4 + 1)
+			return 0; /* packet is incomplete */
+		state->packlen = PEEK_U32(cp);
+		if (state->packlen < 4 + 1 ||
+		    state->packlen > PACKET_MAX_SIZE)
+			return SSH_ERR_MESSAGE_INCOMPLETE;
+	}
+	need = state->packlen + 4;
+	if (sshbuf_len(state->input) < need)
+		return 0; /* packet is incomplete */
+	sshbuf_reset(state->incoming_packet);
+	if ((r = sshbuf_put(state->incoming_packet, cp + 4,
+	    state->packlen)) != 0 ||
+	    (r = sshbuf_consume(state->input, need)) != 0 ||
+	    (r = sshbuf_get_u8(state->incoming_packet, NULL)) != 0 ||
+	    (r = sshbuf_get_u8(state->incoming_packet, typep)) != 0)
+		return r;
+	if (ssh_packet_log_type(*typep))
+		debug3("%s: type %u", __func__, *typep);
+	/* sshbuf_dump(state->incoming_packet, stderr); */
+	/* reset for next packet */
+	state->packlen = 0;
+	return r;
+}
+
+int
+ssh_packet_read_poll2(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
+{
+	struct session_state *state = ssh->state;
+	u_int padlen, need;
+	u_char *cp;
+	u_int maclen, aadlen = 0, authlen = 0, block_size;
+	struct sshenc *enc   = NULL;
+	struct sshmac *mac   = NULL;
+	struct sshcomp *comp = NULL;
+	int r;
+
+	if (state->mux)
+		return ssh_packet_read_poll2_mux(ssh, typep, seqnr_p);
+
+	*typep = SSH_MSG_NONE;
+
+	if (state->packet_discard)
+		return 0;
+
+	if (state->newkeys[MODE_IN] != NULL) {
+		enc  = &state->newkeys[MODE_IN]->enc;
+		mac  = &state->newkeys[MODE_IN]->mac;
+		comp = &state->newkeys[MODE_IN]->comp;
+		/* disable mac for authenticated encryption */
+		if ((authlen = cipher_authlen(enc->cipher)) != 0)
+			mac = NULL;
+	}
+	maclen = mac && mac->enabled ? mac->mac_len : 0;
+	block_size = enc ? enc->block_size : 8;
+	aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0;
+
+	if (aadlen && state->packlen == 0) {
+		if (cipher_get_length(state->receive_context,
+		    &state->packlen, state->p_read.seqnr,
+		    sshbuf_ptr(state->input), sshbuf_len(state->input)) != 0)
+			return 0;
+		if (state->packlen < 1 + 4 ||
+		    state->packlen > PACKET_MAX_SIZE) {
+#ifdef PACKET_DEBUG
+			sshbuf_dump(state->input, stderr);
+#endif
+			logit("Bad packet length %u.", state->packlen);
+			if ((r = sshpkt_disconnect(ssh, "Packet corrupt")) != 0)
+				return r;
+			return SSH_ERR_CONN_CORRUPT;
+		}
+		sshbuf_reset(state->incoming_packet);
+	} else if (state->packlen == 0) {
+		/*
+		 * check if input size is less than the cipher block size,
+		 * decrypt first block and extract length of incoming packet
+		 */
+		if (sshbuf_len(state->input) < block_size)
+			return 0;
+		sshbuf_reset(state->incoming_packet);
+		if ((r = sshbuf_reserve(state->incoming_packet, block_size,
+		    &cp)) != 0)
+			goto out;
+		if ((r = cipher_crypt(state->receive_context,
+		    state->p_send.seqnr, cp, sshbuf_ptr(state->input),
+		    block_size, 0, 0)) != 0)
+			goto out;
+		state->packlen = PEEK_U32(sshbuf_ptr(state->incoming_packet));
+		if (state->packlen < 1 + 4 ||
+		    state->packlen > PACKET_MAX_SIZE) {
+#ifdef PACKET_DEBUG
+			fprintf(stderr, "input: \n");
+			sshbuf_dump(state->input, stderr);
+			fprintf(stderr, "incoming_packet: \n");
+			sshbuf_dump(state->incoming_packet, stderr);
+#endif
+			logit("Bad packet length %u.", state->packlen);
+			return ssh_packet_start_discard(ssh, enc, mac, 0,
+			    PACKET_MAX_SIZE);
+		}
+		if ((r = sshbuf_consume(state->input, block_size)) != 0)
+			goto out;
+	}
+	DBG(debug("input: packet len %u", state->packlen+4));
+
+	if (aadlen) {
+		/* only the payload is encrypted */
+		need = state->packlen;
+	} else {
+		/*
+		 * the payload size and the payload are encrypted, but we
+		 * have a partial packet of block_size bytes
+		 */
+		need = 4 + state->packlen - block_size;
+	}
+	DBG(debug("partial packet: block %d, need %d, maclen %d, authlen %d,"
+	    " aadlen %d", block_size, need, maclen, authlen, aadlen));
+	if (need % block_size != 0) {
+		logit("padding error: need %d block %d mod %d",
+		    need, block_size, need % block_size);
+		return ssh_packet_start_discard(ssh, enc, mac, 0,
+		    PACKET_MAX_SIZE - block_size);
+	}
+	/*
+	 * check if the entire packet has been received and
+	 * decrypt into incoming_packet:
+	 * 'aadlen' bytes are unencrypted, but authenticated.
+	 * 'need' bytes are encrypted, followed by either
+	 * 'authlen' bytes of authentication tag or
+	 * 'maclen' bytes of message authentication code.
+	 */
+	if (sshbuf_len(state->input) < aadlen + need + authlen + maclen)
+		return 0; /* packet is incomplete */
+#ifdef PACKET_DEBUG
+	fprintf(stderr, "read_poll enc/full: ");
+	sshbuf_dump(state->input, stderr);
+#endif
+	/* EtM: check mac over encrypted input */
+	if (mac && mac->enabled && mac->etm) {
+		if ((r = mac_check(mac, state->p_read.seqnr,
+		    sshbuf_ptr(state->input), aadlen + need,
+		    sshbuf_ptr(state->input) + aadlen + need + authlen,
+		    maclen)) != 0) {
+			if (r == SSH_ERR_MAC_INVALID)
+				logit("Corrupted MAC on input.");
+			goto out;
+		}
+	}
+	if ((r = sshbuf_reserve(state->incoming_packet, aadlen + need,
+	    &cp)) != 0)
+		goto out;
+	if ((r = cipher_crypt(state->receive_context, state->p_read.seqnr, cp,
+	    sshbuf_ptr(state->input), need, aadlen, authlen)) != 0)
+		goto out;
+	if ((r = sshbuf_consume(state->input, aadlen + need + authlen)) != 0)
+		goto out;
+	if (mac && mac->enabled) {
+		/* Not EtM: check MAC over cleartext */
+		if (!mac->etm && (r = mac_check(mac, state->p_read.seqnr,
+		    sshbuf_ptr(state->incoming_packet),
+		    sshbuf_len(state->incoming_packet),
+		    sshbuf_ptr(state->input), maclen)) != 0) {
+			if (r != SSH_ERR_MAC_INVALID)
+				goto out;
+			logit("Corrupted MAC on input.");
+			if (need + block_size > PACKET_MAX_SIZE)
+				return SSH_ERR_INTERNAL_ERROR;
+			return ssh_packet_start_discard(ssh, enc, mac,
+			    sshbuf_len(state->incoming_packet),
+			    PACKET_MAX_SIZE - need - block_size);
+		}
+		/* Remove MAC from input buffer */
+		DBG(debug("MAC #%d ok", state->p_read.seqnr));
+		if ((r = sshbuf_consume(state->input, mac->mac_len)) != 0)
+			goto out;
+	}
+	if (seqnr_p != NULL)
+		*seqnr_p = state->p_read.seqnr;
+	if (++state->p_read.seqnr == 0)
+		logit("incoming seqnr wraps around");
+	if (++state->p_read.packets == 0)
+		if (!(ssh->compat & SSH_BUG_NOREKEY))
+			return SSH_ERR_NEED_REKEY;
+	state->p_read.blocks += (state->packlen + 4) / block_size;
+	state->p_read.bytes += state->packlen + 4;
+
+	/* get padlen */
+	padlen = sshbuf_ptr(state->incoming_packet)[4];
+	DBG(debug("input: padlen %d", padlen));
+	if (padlen < 4)	{
+		if ((r = sshpkt_disconnect(ssh,
+		    "Corrupted padlen %d on input.", padlen)) != 0 ||
+		    (r = ssh_packet_write_wait(ssh)) != 0)
+			return r;
+		return SSH_ERR_CONN_CORRUPT;
+	}
+
+	/* skip packet size + padlen, discard padding */
+	if ((r = sshbuf_consume(state->incoming_packet, 4 + 1)) != 0 ||
+	    ((r = sshbuf_consume_end(state->incoming_packet, padlen)) != 0))
+		goto out;
+
+	DBG(debug("input: len before de-compress %zd",
+	    sshbuf_len(state->incoming_packet)));
+	if (comp && comp->enabled) {
+		sshbuf_reset(state->compression_buffer);
+		if ((r = uncompress_buffer(ssh, state->incoming_packet,
+		    state->compression_buffer)) != 0)
+			goto out;
+		sshbuf_reset(state->incoming_packet);
+		if ((r = sshbuf_putb(state->incoming_packet,
+		    state->compression_buffer)) != 0)
+			goto out;
+		DBG(debug("input: len after de-compress %zd",
+		    sshbuf_len(state->incoming_packet)));
+	}
+	/*
+	 * get packet type, implies consume.
+	 * return length of payload (without type field)
+	 */
+	if ((r = sshbuf_get_u8(state->incoming_packet, typep)) != 0)
+		goto out;
+	if (ssh_packet_log_type(*typep))
+		debug3("receive packet: type %u", *typep);
+	if (*typep < SSH2_MSG_MIN || *typep >= SSH2_MSG_LOCAL_MIN) {
+		if ((r = sshpkt_disconnect(ssh,
+		    "Invalid ssh2 packet type: %d", *typep)) != 0 ||
+		    (r = ssh_packet_write_wait(ssh)) != 0)
+			return r;
+		return SSH_ERR_PROTOCOL_ERROR;
+	}
+	if (state->hook_in != NULL &&
+	    (r = state->hook_in(ssh, state->incoming_packet, typep,
+	    state->hook_in_ctx)) != 0)
+		return r;
+	if (*typep == SSH2_MSG_USERAUTH_SUCCESS && !state->server_side)
+		r = ssh_packet_enable_delayed_compress(ssh);
+	else
+		r = 0;
+#ifdef PACKET_DEBUG
+	fprintf(stderr, "read/plain[%d]:\r\n", *typep);
+	sshbuf_dump(state->incoming_packet, stderr);
+#endif
+	/* reset for next packet */
+	state->packlen = 0;
+
+	/* do we need to rekey? */
+	if (ssh_packet_need_rekeying(ssh, 0)) {
+		debug3("%s: rekex triggered", __func__);
+		if ((r = kex_start_rekex(ssh)) != 0)
+			return r;
+	}
+ out:
+	return r;
+}
+
+int
+ssh_packet_read_poll_seqnr(struct ssh *ssh, u_char *typep, u_int32_t *seqnr_p)
+{
+	struct session_state *state = ssh->state;
+	u_int reason, seqnr;
+	int r;
+	u_char *msg;
+
+	for (;;) {
+		msg = NULL;
+		r = ssh_packet_read_poll2(ssh, typep, seqnr_p);
+		if (r != 0)
+			return r;
+		if (*typep) {
+			state->keep_alive_timeouts = 0;
+			DBG(debug("received packet type %d", *typep));
+		}
+		switch (*typep) {
+		case SSH2_MSG_IGNORE:
+			debug3("Received SSH2_MSG_IGNORE");
+			break;
+		case SSH2_MSG_DEBUG:
+			if ((r = sshpkt_get_u8(ssh, NULL)) != 0 ||
+			    (r = sshpkt_get_string(ssh, &msg, NULL)) != 0 ||
+			    (r = sshpkt_get_string(ssh, NULL, NULL)) != 0) {
+				free(msg);
+				return r;
+			}
+			debug("Remote: %.900s", msg);
+			free(msg);
+			break;
+		case SSH2_MSG_DISCONNECT:
+			if ((r = sshpkt_get_u32(ssh, &reason)) != 0 ||
+			    (r = sshpkt_get_string(ssh, &msg, NULL)) != 0)
+				return r;
+			/* Ignore normal client exit notifications */
+			do_log2(ssh->state->server_side &&
+			    reason == SSH2_DISCONNECT_BY_APPLICATION ?
+			    SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_ERROR,
+			    "Received disconnect from %s port %d:"
+			    "%u: %.400s", ssh_remote_ipaddr(ssh),
+			    ssh_remote_port(ssh), reason, msg);
+			free(msg);
+			return SSH_ERR_DISCONNECTED;
+		case SSH2_MSG_UNIMPLEMENTED:
+			if ((r = sshpkt_get_u32(ssh, &seqnr)) != 0)
+				return r;
+			debug("Received SSH2_MSG_UNIMPLEMENTED for %u",
+			    seqnr);
+			break;
+		default:
+			return 0;
+		}
+	}
+}
+
+/*
+ * Buffers the given amount of input characters.  This is intended to be used
+ * together with packet_read_poll.
+ */
+
+int
+ssh_packet_process_incoming(struct ssh *ssh, const char *buf, u_int len)
+{
+	struct session_state *state = ssh->state;
+	int r;
+
+	if (state->packet_discard) {
+		state->keep_alive_timeouts = 0; /* ?? */
+		if (len >= state->packet_discard) {
+			if ((r = ssh_packet_stop_discard(ssh)) != 0)
+				return r;
+		}
+		state->packet_discard -= len;
+		return 0;
+	}
+	if ((r = sshbuf_put(ssh->state->input, buf, len)) != 0)
+		return r;
+
+	return 0;
+}
+
+int
+ssh_packet_remaining(struct ssh *ssh)
+{
+	return sshbuf_len(ssh->state->incoming_packet);
+}
+
+/*
+ * Sends a diagnostic message from the server to the client.  This message
+ * can be sent at any time (but not while constructing another message). The
+ * message is printed immediately, but only if the client is being executed
+ * in verbose mode.  These messages are primarily intended to ease debugging
+ * authentication problems.   The length of the formatted message must not
+ * exceed 1024 bytes.  This will automatically call ssh_packet_write_wait.
+ */
+void
+ssh_packet_send_debug(struct ssh *ssh, const char *fmt,...)
+{
+	char buf[1024];
+	va_list args;
+	int r;
+
+	if ((ssh->compat & SSH_BUG_DEBUG))
+		return;
+
+	va_start(args, fmt);
+	vsnprintf(buf, sizeof(buf), fmt, args);
+	va_end(args);
+
+	debug3("sending debug message: %s", buf);
+
+	if ((r = sshpkt_start(ssh, SSH2_MSG_DEBUG)) != 0 ||
+	    (r = sshpkt_put_u8(ssh, 0)) != 0 || /* always display */
+	    (r = sshpkt_put_cstring(ssh, buf)) != 0 ||
+	    (r = sshpkt_put_cstring(ssh, "")) != 0 ||
+	    (r = sshpkt_send(ssh)) != 0 ||
+	    (r = ssh_packet_write_wait(ssh)) != 0)
+		fatal("%s: %s", __func__, ssh_err(r));
+}
+
+void
+sshpkt_fmt_connection_id(struct ssh *ssh, char *s, size_t l)
+{
+	snprintf(s, l, "%.200s%s%s port %d",
+	    ssh->log_preamble ? ssh->log_preamble : "",
+	    ssh->log_preamble ? " " : "",
+	    ssh_remote_ipaddr(ssh), ssh_remote_port(ssh));
+}
+
+/*
+ * Pretty-print connection-terminating errors and exit.
+ */
+void
+sshpkt_fatal(struct ssh *ssh, const char *tag, int r)
+{
+	char remote_id[512];
+
+	sshpkt_fmt_connection_id(ssh, remote_id, sizeof(remote_id));
+
+	switch (r) {
+	case SSH_ERR_CONN_CLOSED:
+		ssh_packet_clear_keys(ssh);
+		logdie("Connection closed by %s", remote_id);
+	case SSH_ERR_CONN_TIMEOUT:
+		ssh_packet_clear_keys(ssh);
+		logdie("Connection %s %s timed out",
+		    ssh->state->server_side ? "from" : "to", remote_id);
+	case SSH_ERR_DISCONNECTED:
+		ssh_packet_clear_keys(ssh);
+		logdie("Disconnected from %s", remote_id);
+	case SSH_ERR_SYSTEM_ERROR:
+		if (errno == ECONNRESET) {
+			ssh_packet_clear_keys(ssh);
+			logdie("Connection reset by %s", remote_id);
+		}
+		/* FALLTHROUGH */
+	case SSH_ERR_NO_CIPHER_ALG_MATCH:
+	case SSH_ERR_NO_MAC_ALG_MATCH:
+	case SSH_ERR_NO_COMPRESS_ALG_MATCH:
+	case SSH_ERR_NO_KEX_ALG_MATCH:
+	case SSH_ERR_NO_HOSTKEY_ALG_MATCH:
+		if (ssh && ssh->kex && ssh->kex->failed_choice) {
+			ssh_packet_clear_keys(ssh);
+			logdie("Unable to negotiate with %s: %s. "
+			    "Their offer: %s", remote_id, ssh_err(r),
+			    ssh->kex->failed_choice);
+		}
+		/* FALLTHROUGH */
+	default:
+		ssh_packet_clear_keys(ssh);
+		logdie("%s%sConnection %s %s: %s",
+		    tag != NULL ? tag : "", tag != NULL ? ": " : "",
+		    ssh->state->server_side ? "from" : "to",
+		    remote_id, ssh_err(r));
+	}
+}
+
+/*
+ * Logs the error plus constructs and sends a disconnect packet, closes the
+ * connection, and exits.  This function never returns. The error message
+ * should not contain a newline.  The length of the formatted message must
+ * not exceed 1024 bytes.
+ */
+void
+ssh_packet_disconnect(struct ssh *ssh, const char *fmt,...)
+{
+	char buf[1024], remote_id[512];
+	va_list args;
+	static int disconnecting = 0;
+	int r;
+
+	if (disconnecting)	/* Guard against recursive invocations. */
+		fatal("packet_disconnect called recursively.");
+	disconnecting = 1;
+
+	/*
+	 * Format the message.  Note that the caller must make sure the
+	 * message is of limited size.
+	 */
+	sshpkt_fmt_connection_id(ssh, remote_id, sizeof(remote_id));
+	va_start(args, fmt);
+	vsnprintf(buf, sizeof(buf), fmt, args);
+	va_end(args);
+
+	/* Display the error locally */
+	logit("Disconnecting %s: %.100s", remote_id, buf);
+
+	/*
+	 * Send the disconnect message to the other side, and wait
+	 * for it to get sent.
+	 */
+	if ((r = sshpkt_disconnect(ssh, "%s", buf)) != 0)
+		sshpkt_fatal(ssh, __func__, r);
+
+	if ((r = ssh_packet_write_wait(ssh)) != 0)
+		sshpkt_fatal(ssh, __func__, r);
+
+	/* Close the connection. */
+	ssh_packet_close(ssh);
+	cleanup_exit(255);
+}
+
+/*
+ * Checks if there is any buffered output, and tries to write some of
+ * the output.
+ */
+int
+ssh_packet_write_poll(struct ssh *ssh)
+{
+	struct session_state *state = ssh->state;
+	int len = sshbuf_len(state->output);
+	int r;
+
+	if (len > 0) {
+		len = write(state->connection_out,
+		    sshbuf_ptr(state->output), len);
+		if (len == -1) {
+			if (errno == EINTR || errno == EAGAIN ||
+			    errno == EWOULDBLOCK)
+				return 0;
+			return SSH_ERR_SYSTEM_ERROR;
+		}
+		if (len == 0)
+			return SSH_ERR_CONN_CLOSED;
+		if ((r = sshbuf_consume(state->output, len)) != 0)
+			return r;
+	}
+	return 0;
+}
+
+/*
+ * Calls packet_write_poll repeatedly until all pending output data has been
+ * written.
+ */
+int
+ssh_packet_write_wait(struct ssh *ssh)
+{
+	fd_set *setp;
+	int ret, r, ms_remain = 0;
+	struct timeval start, timeout, *timeoutp = NULL;
+	struct session_state *state = ssh->state;
+
+	setp = calloc(howmany(state->connection_out + 1,
+	    NFDBITS), sizeof(fd_mask));
+	if (setp == NULL)
+		return SSH_ERR_ALLOC_FAIL;
+	if ((r = ssh_packet_write_poll(ssh)) != 0) {
+		free(setp);
+		return r;
+	}
+	while (ssh_packet_have_data_to_write(ssh)) {
+		memset(setp, 0, howmany(state->connection_out + 1,
+		    NFDBITS) * sizeof(fd_mask));
+		FD_SET(state->connection_out, setp);
+
+		if (state->packet_timeout_ms > 0) {
+			ms_remain = state->packet_timeout_ms;
+			timeoutp = &timeout;
+		}
+		for (;;) {
+			if (state->packet_timeout_ms != -1) {
+				ms_to_timeval(&timeout, ms_remain);
+				monotime_tv(&start);
+			}
+			if ((ret = select(state->connection_out + 1,
+			    NULL, setp, NULL, timeoutp)) >= 0)
+				break;
+			if (errno != EAGAIN && errno != EINTR &&
+			    errno != EWOULDBLOCK)
+				break;
+			if (state->packet_timeout_ms == -1)
+				continue;
+			ms_subtract_diff(&start, &ms_remain);
+			if (ms_remain <= 0) {
+				ret = 0;
+				break;
+			}
+		}
+		if (ret == 0) {
+			free(setp);
+			return SSH_ERR_CONN_TIMEOUT;
+		}
+		if ((r = ssh_packet_write_poll(ssh)) != 0) {
+			free(setp);
+			return r;
+		}
+	}
+	free(setp);
+	return 0;
+}
+
+/* Returns true if there is buffered data to write to the connection. */
+
+int
+ssh_packet_have_data_to_write(struct ssh *ssh)
+{
+	return sshbuf_len(ssh->state->output) != 0;
+}
+
+/* Returns true if there is not too much data to write to the connection. */
+
+int
+ssh_packet_not_very_much_data_to_write(struct ssh *ssh)
+{
+	if (ssh->state->interactive_mode)
+		return sshbuf_len(ssh->state->output) < 16384;
+	else
+		return sshbuf_len(ssh->state->output) < 128 * 1024;
+}
+
+void
+ssh_packet_set_tos(struct ssh *ssh, int tos)
+{
+#ifndef IP_TOS_IS_BROKEN
+	if (!ssh_packet_connection_is_on_socket(ssh) || tos == INT_MAX)
+		return;
+	switch (ssh_packet_connection_af(ssh)) {
+# ifdef IP_TOS
+	case AF_INET:
+		debug3("%s: set IP_TOS 0x%02x", __func__, tos);
+		if (setsockopt(ssh->state->connection_in,
+		    IPPROTO_IP, IP_TOS, &tos, sizeof(tos)) < 0)
+			error("setsockopt IP_TOS %d: %.100s:",
+			    tos, strerror(errno));
+		break;
+# endif /* IP_TOS */
+# ifdef IPV6_TCLASS
+	case AF_INET6:
+		debug3("%s: set IPV6_TCLASS 0x%02x", __func__, tos);
+		if (setsockopt(ssh->state->connection_in,
+		    IPPROTO_IPV6, IPV6_TCLASS, &tos, sizeof(tos)) < 0)
+			error("setsockopt IPV6_TCLASS %d: %.100s:",
+			    tos, strerror(errno));
+		break;
+# endif /* IPV6_TCLASS */
+	}
+#endif /* IP_TOS_IS_BROKEN */
+}
+
+/* Informs that the current session is interactive.  Sets IP flags for that. */
+
+void
+ssh_packet_set_interactive(struct ssh *ssh, int interactive, int qos_interactive, int qos_bulk)
+{
+	struct session_state *state = ssh->state;
+
+	if (state->set_interactive_called)
+		return;
+	state->set_interactive_called = 1;
+
+	/* Record that we are in interactive mode. */
+	state->interactive_mode = interactive;
+
+	/* Only set socket options if using a socket.  */
+	if (!ssh_packet_connection_is_on_socket(ssh))
+		return;
+	set_nodelay(state->connection_in);
+	ssh_packet_set_tos(ssh, interactive ? qos_interactive :
+	    qos_bulk);
+}
+
+/* Returns true if the current connection is interactive. */
+
+int
+ssh_packet_is_interactive(struct ssh *ssh)
+{
+	return ssh->state->interactive_mode;
+}
+
+int
+ssh_packet_set_maxsize(struct ssh *ssh, u_int s)
+{
+	struct session_state *state = ssh->state;
+
+	if (state->set_maxsize_called) {
+		logit("packet_set_maxsize: called twice: old %d new %d",
+		    state->max_packet_size, s);
+		return -1;
+	}
+	if (s < 4 * 1024 || s > 1024 * 1024) {
+		logit("packet_set_maxsize: bad size %d", s);
+		return -1;
+	}
+	state->set_maxsize_called = 1;
+	debug("packet_set_maxsize: setting to %d", s);
+	state->max_packet_size = s;
+	return s;
+}
+
+int
+ssh_packet_inc_alive_timeouts(struct ssh *ssh)
+{
+	return ++ssh->state->keep_alive_timeouts;
+}
+
+void
+ssh_packet_set_alive_timeouts(struct ssh *ssh, int ka)
+{
+	ssh->state->keep_alive_timeouts = ka;
+}
+
+u_int
+ssh_packet_get_maxsize(struct ssh *ssh)
+{
+	return ssh->state->max_packet_size;
+}
+
+void
+ssh_packet_set_rekey_limits(struct ssh *ssh, u_int64_t bytes, u_int32_t seconds)
+{
+	debug3("rekey after %llu bytes, %u seconds", (unsigned long long)bytes,
+	    (unsigned int)seconds);
+	ssh->state->rekey_limit = bytes;
+	ssh->state->rekey_interval = seconds;
+}
+
+time_t
+ssh_packet_get_rekey_timeout(struct ssh *ssh)
+{
+	time_t seconds;
+
+	seconds = ssh->state->rekey_time + ssh->state->rekey_interval -
+	    monotime();
+	return (seconds <= 0 ? 1 : seconds);
+}
+
+void
+ssh_packet_set_server(struct ssh *ssh)
+{
+	ssh->state->server_side = 1;
+}
+
+void
+ssh_packet_set_authenticated(struct ssh *ssh)
+{
+	ssh->state->after_authentication = 1;
+}
+
+void *
+ssh_packet_get_input(struct ssh *ssh)
+{
+	return (void *)ssh->state->input;
+}
+
+void *
+ssh_packet_get_output(struct ssh *ssh)
+{
+	return (void *)ssh->state->output;
+}
+
+/* Reset after_authentication and reset compression in post-auth privsep */
+static int
+ssh_packet_set_postauth(struct ssh *ssh)
+{
+	int r;
+
+	debug("%s: called", __func__);
+	/* This was set in net child, but is not visible in user child */
+	ssh->state->after_authentication = 1;
+	ssh->state->rekeying = 0;
+	if ((r = ssh_packet_enable_delayed_compress(ssh)) != 0)
+		return r;
+	return 0;
+}
+
+/* Packet state (de-)serialization for privsep */
+
+/* turn kex into a blob for packet state serialization */
+static int
+kex_to_blob(struct sshbuf *m, struct kex *kex)
+{
+	int r;
+
+	if ((r = sshbuf_put_string(m, kex->session_id,
+	    kex->session_id_len)) != 0 ||
+	    (r = sshbuf_put_u32(m, kex->we_need)) != 0 ||
+	    (r = sshbuf_put_cstring(m, kex->hostkey_alg)) != 0 ||
+	    (r = sshbuf_put_u32(m, kex->hostkey_type)) != 0 ||
+	    (r = sshbuf_put_u32(m, kex->hostkey_nid)) != 0 ||
+	    (r = sshbuf_put_u32(m, kex->kex_type)) != 0 ||
+	    (r = sshbuf_put_stringb(m, kex->my)) != 0 ||
+	    (r = sshbuf_put_stringb(m, kex->peer)) != 0 ||
+	    (r = sshbuf_put_u32(m, kex->flags)) != 0 ||
+	    (r = sshbuf_put_cstring(m, kex->client_version_string)) != 0 ||
+	    (r = sshbuf_put_cstring(m, kex->server_version_string)) != 0)
+		return r;
+	return 0;
+}
+
+/* turn key exchange results into a blob for packet state serialization */
+static int
+newkeys_to_blob(struct sshbuf *m, struct ssh *ssh, int mode)
+{
+	struct sshbuf *b;
+	struct sshcipher_ctx *cc;
+	struct sshcomp *comp;
+	struct sshenc *enc;
+	struct sshmac *mac;
+	struct newkeys *newkey;
+	int r;
+
+	if ((newkey = ssh->state->newkeys[mode]) == NULL)
+		return SSH_ERR_INTERNAL_ERROR;
+	enc = &newkey->enc;
+	mac = &newkey->mac;
+	comp = &newkey->comp;
+	cc = (mode == MODE_OUT) ? ssh->state->send_context :
+	    ssh->state->receive_context;
+	if ((r = cipher_get_keyiv(cc, enc->iv, enc->iv_len)) != 0)
+		return r;
+	if ((b = sshbuf_new()) == NULL)
+		return SSH_ERR_ALLOC_FAIL;
+	if ((r = sshbuf_put_cstring(b, enc->name)) != 0 ||
+	    (r = sshbuf_put_u32(b, enc->enabled)) != 0 ||
+	    (r = sshbuf_put_u32(b, enc->block_size)) != 0 ||
+	    (r = sshbuf_put_string(b, enc->key, enc->key_len)) != 0 ||
+	    (r = sshbuf_put_string(b, enc->iv, enc->iv_len)) != 0)
+		goto out;
+	if (cipher_authlen(enc->cipher) == 0) {
+		if ((r = sshbuf_put_cstring(b, mac->name)) != 0 ||
+		    (r = sshbuf_put_u32(b, mac->enabled)) != 0 ||
+		    (r = sshbuf_put_string(b, mac->key, mac->key_len)) != 0)
+			goto out;
+	}
+	if ((r = sshbuf_put_u32(b, comp->type)) != 0 ||
+	    (r = sshbuf_put_cstring(b, comp->name)) != 0)
+		goto out;
+	r = sshbuf_put_stringb(m, b);
+ out:
+	sshbuf_free(b);
+	return r;
+}
+
+/* serialize packet state into a blob */
+int
+ssh_packet_get_state(struct ssh *ssh, struct sshbuf *m)
+{
+	struct session_state *state = ssh->state;
+	int r;
+
+	if ((r = kex_to_blob(m, ssh->kex)) != 0 ||
+	    (r = newkeys_to_blob(m, ssh, MODE_OUT)) != 0 ||
+	    (r = newkeys_to_blob(m, ssh, MODE_IN)) != 0 ||
+	    (r = sshbuf_put_u64(m, state->rekey_limit)) != 0 ||
+	    (r = sshbuf_put_u32(m, state->rekey_interval)) != 0 ||
+	    (r = sshbuf_put_u32(m, state->p_send.seqnr)) != 0 ||
+	    (r = sshbuf_put_u64(m, state->p_send.blocks)) != 0 ||
+	    (r = sshbuf_put_u32(m, state->p_send.packets)) != 0 ||
+	    (r = sshbuf_put_u64(m, state->p_send.bytes)) != 0 ||
+	    (r = sshbuf_put_u32(m, state->p_read.seqnr)) != 0 ||
+	    (r = sshbuf_put_u64(m, state->p_read.blocks)) != 0 ||
+	    (r = sshbuf_put_u32(m, state->p_read.packets)) != 0 ||
+	    (r = sshbuf_put_u64(m, state->p_read.bytes)) != 0 ||
+	    (r = sshbuf_put_stringb(m, state->input)) != 0 ||
+	    (r = sshbuf_put_stringb(m, state->output)) != 0)
+		return r;
+
+	return 0;
+}
+
+/* restore key exchange results from blob for packet state de-serialization */
+static int
+newkeys_from_blob(struct sshbuf *m, struct ssh *ssh, int mode)
+{
+	struct sshbuf *b = NULL;
+	struct sshcomp *comp;
+	struct sshenc *enc;
+	struct sshmac *mac;
+	struct newkeys *newkey = NULL;
+	size_t keylen, ivlen, maclen;
+	int r;
+
+	if ((newkey = calloc(1, sizeof(*newkey))) == NULL) {
+		r = SSH_ERR_ALLOC_FAIL;
+		goto out;
+	}
+	if ((r = sshbuf_froms(m, &b)) != 0)
+		goto out;
+#ifdef DEBUG_PK
+	sshbuf_dump(b, stderr);
+#endif
+	enc = &newkey->enc;
+	mac = &newkey->mac;
+	comp = &newkey->comp;
+
+	if ((r = sshbuf_get_cstring(b, &enc->name, NULL)) != 0 ||
+	    (r = sshbuf_get_u32(b, (u_int *)&enc->enabled)) != 0 ||
+	    (r = sshbuf_get_u32(b, &enc->block_size)) != 0 ||
+	    (r = sshbuf_get_string(b, &enc->key, &keylen)) != 0 ||
+	    (r = sshbuf_get_string(b, &enc->iv, &ivlen)) != 0)
+		goto out;
+	if ((enc->cipher = cipher_by_name(enc->name)) == NULL) {
+		r = SSH_ERR_INVALID_FORMAT;
+		goto out;
+	}
+	if (cipher_authlen(enc->cipher) == 0) {
+		if ((r = sshbuf_get_cstring(b, &mac->name, NULL)) != 0)
+			goto out;
+		if ((r = mac_setup(mac, mac->name)) != 0)
+			goto out;
+		if ((r = sshbuf_get_u32(b, (u_int *)&mac->enabled)) != 0 ||
+		    (r = sshbuf_get_string(b, &mac->key, &maclen)) != 0)
+			goto out;
+		if (maclen > mac->key_len) {
+			r = SSH_ERR_INVALID_FORMAT;
+			goto out;
+		}
+		mac->key_len = maclen;
+	}
+	if ((r = sshbuf_get_u32(b, &comp->type)) != 0 ||
+	    (r = sshbuf_get_cstring(b, &comp->name, NULL)) != 0)
+		goto out;
+	if (sshbuf_len(b) != 0) {
+		r = SSH_ERR_INVALID_FORMAT;
+		goto out;
+	}
+	enc->key_len = keylen;
+	enc->iv_len = ivlen;
+	ssh->kex->newkeys[mode] = newkey;
+	newkey = NULL;
+	r = 0;
+ out:
+	free(newkey);
+	sshbuf_free(b);
+	return r;
+}
+
+/* restore kex from blob for packet state de-serialization */
+static int
+kex_from_blob(struct sshbuf *m, struct kex **kexp)
+{
+	struct kex *kex;
+	int r;
+
+	if ((kex = calloc(1, sizeof(struct kex))) == NULL ||
+	    (kex->my = sshbuf_new()) == NULL ||
+	    (kex->peer = sshbuf_new()) == NULL) {
+		r = SSH_ERR_ALLOC_FAIL;
+		goto out;
+	}
+	if ((r = sshbuf_get_string(m, &kex->session_id, &kex->session_id_len)) != 0 ||
+	    (r = sshbuf_get_u32(m, &kex->we_need)) != 0 ||
+	    (r = sshbuf_get_cstring(m, &kex->hostkey_alg, NULL)) != 0 ||
+	    (r = sshbuf_get_u32(m, (u_int *)&kex->hostkey_type)) != 0 ||
+	    (r = sshbuf_get_u32(m, (u_int *)&kex->hostkey_nid)) != 0 ||
+	    (r = sshbuf_get_u32(m, &kex->kex_type)) != 0 ||
+	    (r = sshbuf_get_stringb(m, kex->my)) != 0 ||
+	    (r = sshbuf_get_stringb(m, kex->peer)) != 0 ||
+	    (r = sshbuf_get_u32(m, &kex->flags)) != 0 ||
+	    (r = sshbuf_get_cstring(m, &kex->client_version_string, NULL)) != 0 ||
+	    (r = sshbuf_get_cstring(m, &kex->server_version_string, NULL)) != 0)
+		goto out;
+	kex->server = 1;
+	kex->done = 1;
+	r = 0;
+ out:
+	if (r != 0 || kexp == NULL) {
+		if (kex != NULL) {
+			sshbuf_free(kex->my);
+			sshbuf_free(kex->peer);
+			free(kex);
+		}
+		if (kexp != NULL)
+			*kexp = NULL;
+	} else {
+		*kexp = kex;
+	}
+	return r;
+}
+
+/*
+ * Restore packet state from content of blob 'm' (de-serialization).
+ * Note that 'm' will be partially consumed on parsing or any other errors.
+ */
+int
+ssh_packet_set_state(struct ssh *ssh, struct sshbuf *m)
+{
+	struct session_state *state = ssh->state;
+	const u_char *input, *output;
+	size_t ilen, olen;
+	int r;
+
+	if ((r = kex_from_blob(m, &ssh->kex)) != 0 ||
+	    (r = newkeys_from_blob(m, ssh, MODE_OUT)) != 0 ||
+	    (r = newkeys_from_blob(m, ssh, MODE_IN)) != 0 ||
+	    (r = sshbuf_get_u64(m, &state->rekey_limit)) != 0 ||
+	    (r = sshbuf_get_u32(m, &state->rekey_interval)) != 0 ||
+	    (r = sshbuf_get_u32(m, &state->p_send.seqnr)) != 0 ||
+	    (r = sshbuf_get_u64(m, &state->p_send.blocks)) != 0 ||
+	    (r = sshbuf_get_u32(m, &state->p_send.packets)) != 0 ||
+	    (r = sshbuf_get_u64(m, &state->p_send.bytes)) != 0 ||
+	    (r = sshbuf_get_u32(m, &state->p_read.seqnr)) != 0 ||
+	    (r = sshbuf_get_u64(m, &state->p_read.blocks)) != 0 ||
+	    (r = sshbuf_get_u32(m, &state->p_read.packets)) != 0 ||
+	    (r = sshbuf_get_u64(m, &state->p_read.bytes)) != 0)
+		return r;
+	/*
+	 * We set the time here so that in post-auth privsep slave we
+	 * count from the completion of the authentication.
+	 */
+	state->rekey_time = monotime();
+	/* XXX ssh_set_newkeys overrides p_read.packets? XXX */
+	if ((r = ssh_set_newkeys(ssh, MODE_IN)) != 0 ||
+	    (r = ssh_set_newkeys(ssh, MODE_OUT)) != 0)
+		return r;
+
+	if ((r = ssh_packet_set_postauth(ssh)) != 0)
+		return r;
+
+	sshbuf_reset(state->input);
+	sshbuf_reset(state->output);
+	if ((r = sshbuf_get_string_direct(m, &input, &ilen)) != 0 ||
+	    (r = sshbuf_get_string_direct(m, &output, &olen)) != 0 ||
+	    (r = sshbuf_put(state->input, input, ilen)) != 0 ||
+	    (r = sshbuf_put(state->output, output, olen)) != 0)
+		return r;
+
+	if (sshbuf_len(m))
+		return SSH_ERR_INVALID_FORMAT;
+	debug3("%s: done", __func__);
+	return 0;
+}
+
+/* NEW API */
+
+/* put data to the outgoing packet */
+
+int
+sshpkt_put(struct ssh *ssh, const void *v, size_t len)
+{
+	return sshbuf_put(ssh->state->outgoing_packet, v, len);
+}
+
+int
+sshpkt_putb(struct ssh *ssh, const struct sshbuf *b)
+{
+	return sshbuf_putb(ssh->state->outgoing_packet, b);
+}
+
+int
+sshpkt_put_u8(struct ssh *ssh, u_char val)
+{
+	return sshbuf_put_u8(ssh->state->outgoing_packet, val);
+}
+
+int
+sshpkt_put_u32(struct ssh *ssh, u_int32_t val)
+{
+	return sshbuf_put_u32(ssh->state->outgoing_packet, val);
+}
+
+int
+sshpkt_put_u64(struct ssh *ssh, u_int64_t val)
+{
+	return sshbuf_put_u64(ssh->state->outgoing_packet, val);
+}
+
+int
+sshpkt_put_string(struct ssh *ssh, const void *v, size_t len)
+{
+	return sshbuf_put_string(ssh->state->outgoing_packet, v, len);
+}
+
+int
+sshpkt_put_cstring(struct ssh *ssh, const void *v)
+{
+	return sshbuf_put_cstring(ssh->state->outgoing_packet, v);
+}
+
+int
+sshpkt_put_stringb(struct ssh *ssh, const struct sshbuf *v)
+{
+	return sshbuf_put_stringb(ssh->state->outgoing_packet, v);
+}
+
+#ifdef WITH_OPENSSL
+#ifdef OPENSSL_HAS_ECC
+int
+sshpkt_put_ec(struct ssh *ssh, const EC_POINT *v, const EC_GROUP *g)
+{
+	return sshbuf_put_ec(ssh->state->outgoing_packet, v, g);
+}
+#endif /* OPENSSL_HAS_ECC */
+
+
+int
+sshpkt_put_bignum2(struct ssh *ssh, const BIGNUM *v)
+{
+	return sshbuf_put_bignum2(ssh->state->outgoing_packet, v);
+}
+#endif /* WITH_OPENSSL */
+
+/* fetch data from the incoming packet */
+
+int
+sshpkt_get(struct ssh *ssh, void *valp, size_t len)
+{
+	return sshbuf_get(ssh->state->incoming_packet, valp, len);
+}
+
+int
+sshpkt_get_u8(struct ssh *ssh, u_char *valp)
+{
+	return sshbuf_get_u8(ssh->state->incoming_packet, valp);
+}
+
+int
+sshpkt_get_u32(struct ssh *ssh, u_int32_t *valp)
+{
+	return sshbuf_get_u32(ssh->state->incoming_packet, valp);
+}
+
+int
+sshpkt_get_u64(struct ssh *ssh, u_int64_t *valp)
+{
+	return sshbuf_get_u64(ssh->state->incoming_packet, valp);
+}
+
+int
+sshpkt_get_string(struct ssh *ssh, u_char **valp, size_t *lenp)
+{
+	return sshbuf_get_string(ssh->state->incoming_packet, valp, lenp);
+}
+
+int
+sshpkt_get_string_direct(struct ssh *ssh, const u_char **valp, size_t *lenp)
+{
+	return sshbuf_get_string_direct(ssh->state->incoming_packet, valp, lenp);
+}
+
+int
+sshpkt_peek_string_direct(struct ssh *ssh, const u_char **valp, size_t *lenp)
+{
+	return sshbuf_peek_string_direct(ssh->state->incoming_packet, valp, lenp);
+}
+
+int
+sshpkt_get_cstring(struct ssh *ssh, char **valp, size_t *lenp)
+{
+	return sshbuf_get_cstring(ssh->state->incoming_packet, valp, lenp);
+}
+
+#ifdef WITH_OPENSSL
+#ifdef OPENSSL_HAS_ECC
+int
+sshpkt_get_ec(struct ssh *ssh, EC_POINT *v, const EC_GROUP *g)
+{
+	return sshbuf_get_ec(ssh->state->incoming_packet, v, g);
+}
+#endif /* OPENSSL_HAS_ECC */
+
+
+int
+sshpkt_get_bignum2(struct ssh *ssh, BIGNUM *v)
+{
+	return sshbuf_get_bignum2(ssh->state->incoming_packet, v);
+}
+#endif /* WITH_OPENSSL */
+
+int
+sshpkt_get_end(struct ssh *ssh)
+{
+	if (sshbuf_len(ssh->state->incoming_packet) > 0)
+		return SSH_ERR_UNEXPECTED_TRAILING_DATA;
+	return 0;
+}
+
+const u_char *
+sshpkt_ptr(struct ssh *ssh, size_t *lenp)
+{
+	if (lenp != NULL)
+		*lenp = sshbuf_len(ssh->state->incoming_packet);
+	return sshbuf_ptr(ssh->state->incoming_packet);
+}
+
+/* start a new packet */
+
+int
+sshpkt_start(struct ssh *ssh, u_char type)
+{
+	u_char buf[6]; /* u32 packet length, u8 pad len, u8 type */
+
+	DBG(debug("packet_start[%d]", type));
+	memset(buf, 0, sizeof(buf));
+	buf[sizeof(buf) - 1] = type;
+	sshbuf_reset(ssh->state->outgoing_packet);
+	return sshbuf_put(ssh->state->outgoing_packet, buf, sizeof(buf));
+}
+
+static int
+ssh_packet_send_mux(struct ssh *ssh)
+{
+	struct session_state *state = ssh->state;
+	u_char type, *cp;
+	size_t len;
+	int r;
+
+	if (ssh->kex)
+		return SSH_ERR_INTERNAL_ERROR;
+	len = sshbuf_len(state->outgoing_packet);
+	if (len < 6)
+		return SSH_ERR_INTERNAL_ERROR;
+	cp = sshbuf_mutable_ptr(state->outgoing_packet);
+	type = cp[5];
+	if (ssh_packet_log_type(type))
+		debug3("%s: type %u", __func__, type);
+	/* drop everything, but the connection protocol */
+	if (type >= SSH2_MSG_CONNECTION_MIN &&
+	    type <= SSH2_MSG_CONNECTION_MAX) {
+		POKE_U32(cp, len - 4);
+		if ((r = sshbuf_putb(state->output,
+		    state->outgoing_packet)) != 0)
+			return r;
+		/* sshbuf_dump(state->output, stderr); */
+	}
+	sshbuf_reset(state->outgoing_packet);
+	return 0;
+}
+
+/*
+ * 9.2.  Ignored Data Message
+ *
+ *   byte      SSH_MSG_IGNORE
+ *   string    data
+ *
+ * All implementations MUST understand (and ignore) this message at any
+ * time (after receiving the protocol version). No implementation is
+ * required to send them. This message can be used as an additional
+ * protection measure against advanced traffic analysis techniques.
+ */
+int
+sshpkt_msg_ignore(struct ssh *ssh, u_int nbytes)
+{
+	u_int32_t rnd = 0;
+	int r;
+	u_int i;
+
+	if ((r = sshpkt_start(ssh, SSH2_MSG_IGNORE)) != 0 ||
+	    (r = sshpkt_put_u32(ssh, nbytes)) != 0)
+		return r;
+	for (i = 0; i < nbytes; i++) {
+		if (i % 4 == 0)
+			rnd = arc4random();
+		if ((r = sshpkt_put_u8(ssh, (u_char)rnd & 0xff)) != 0)
+			return r;
+		rnd >>= 8;
+	}
+	return 0;
+}
+
+/* send it */
+
+int
+sshpkt_send(struct ssh *ssh)
+{
+	if (ssh->state && ssh->state->mux)
+		return ssh_packet_send_mux(ssh);
+	return ssh_packet_send2(ssh);
+}
+
+int
+sshpkt_disconnect(struct ssh *ssh, const char *fmt,...)
+{
+	char buf[1024];
+	va_list args;
+	int r;
+
+	va_start(args, fmt);
+	vsnprintf(buf, sizeof(buf), fmt, args);
+	va_end(args);
+
+	if ((r = sshpkt_start(ssh, SSH2_MSG_DISCONNECT)) != 0 ||
+	    (r = sshpkt_put_u32(ssh, SSH2_DISCONNECT_PROTOCOL_ERROR)) != 0 ||
+	    (r = sshpkt_put_cstring(ssh, buf)) != 0 ||
+	    (r = sshpkt_put_cstring(ssh, "")) != 0 ||
+	    (r = sshpkt_send(ssh)) != 0)
+		return r;
+	return 0;
+}
+
+/* roundup current message to pad bytes */
+int
+sshpkt_add_padding(struct ssh *ssh, u_char pad)
+{
+	ssh->state->extra_pad = pad;
+	return 0;
+}