[tor/master] Merge branch 'maint-0.2.9' into maint-0.3.5 - tor-commits

6 Nov 2019

commit 1bde356bf645f3c3d3b0a6e70c03e2baf9f89d26
Merge: 4abfcb799 0650bf369
Author: teor teor@torproject.org
Date:   Wed Nov 6 11:19:30 2019 +1000
Merge branch 'maint-0.2.9' into maint-0.3.5
changes/bug31107         |  4 ++++
 src/core/or/channeltls.c | 10 +++++++++-
 2 files changed, 13 insertions(+), 1 deletion(-)
diff --cc src/core/or/channeltls.c
index 91a424728,000000000..4db283d20
mode 100644,000000..100644

--- a/src/core/or/channeltls.c
+++ b/src/core/or/channeltls.c
@@@ -1,2477 -1,0 +1,2485 @@@
 +/* * Copyright (c) 2012-2019, The Tor Project, Inc. */
 +/* See LICENSE for licensing information */
 +
 +/**
 + * \file channeltls.c
 + *
 + * \brief A concrete subclass of channel_t using or_connection_t to transfer
 + * cells between Tor instances.
 + *
 + * This module fills in the various function pointers in channel_t, to
 + * implement the channel_tls_t channels as used in Tor today.  These channels
 + * are created from channel_tls_connect() and
 + * channel_tls_handle_incoming(). Each corresponds 1:1 to or_connection_t
 + * object, as implemented in connection_or.c.  These channels transmit cells
 + * to the underlying or_connection_t by calling
 + * connection_or_write_*_cell_to_buf(), and receive cells from the underlying
 + * or_connection_t when connection_or_process_cells_from_inbuf() calls
 + * channel_tls_handle_*_cell().
 + *
 + * Here we also implement the server (responder) side of the v3+ Tor link
 + * handshake, which uses CERTS and AUTHENTICATE cell to negotiate versions,
 + * exchange expected and observed IP and time information, and bootstrap a
 + * level of authentication higher than we have gotten on the raw TLS
 + * handshake.
 + *
 + * NOTE: Since there is currently only one type of channel, there are probably
 + * more than a few cases where functionality that is currently in
 + * channeltls.c, connection_or.c, and channel.c ought to be divided up
 + * differently.  The right time to do this is probably whenever we introduce
 + * our next channel type.
 + **/
 +
 +/*
 + * Define this so channel.h gives us things only channel_t subclasses
 + * should touch.
 + */
 +#define TOR_CHANNEL_INTERNAL_
 +
 +#define CHANNELTLS_PRIVATE
 +
 +#include "core/or/or.h"
 +#include "core/or/channel.h"
 +#include "core/or/channeltls.h"
 +#include "core/or/circuitmux.h"
 +#include "core/or/circuitmux_ewma.h"
 +#include "core/or/command.h"
 +#include "app/config/config.h"
 +#include "core/mainloop/connection.h"
 +#include "core/or/connection_or.h"
 +#include "feature/control/control.h"
 +#include "feature/client/entrynodes.h"
 +#include "trunnel/link_handshake.h"
 +#include "core/or/relay.h"
 +#include "feature/stats/rephist.h"
 +#include "feature/relay/router.h"
 +#include "feature/relay/routermode.h"
 +#include "feature/nodelist/dirlist.h"
 +#include "core/or/scheduler.h"
 +#include "feature/nodelist/torcert.h"
 +#include "feature/nodelist/networkstatus.h"
 +#include "trunnel/channelpadding_negotiation.h"
 +#include "core/or/channelpadding.h"
 +
 +#include "core/or/cell_st.h"
 +#include "core/or/cell_queue_st.h"
 +#include "core/or/extend_info_st.h"
 +#include "core/or/or_connection_st.h"
 +#include "core/or/or_handshake_certs_st.h"
 +#include "core/or/or_handshake_state_st.h"
 +#include "feature/nodelist/routerinfo_st.h"
 +#include "core/or/var_cell_st.h"
 +
 +#include "lib/tls/tortls.h"
 +#include "lib/tls/x509.h"
 +
 +/** How many CELL_PADDING cells have we received, ever? */
 +uint64_t stats_n_padding_cells_processed = 0;
 +/** How many CELL_VERSIONS cells have we received, ever? */
 +uint64_t stats_n_versions_cells_processed = 0;
 +/** How many CELL_NETINFO cells have we received, ever? */
 +uint64_t stats_n_netinfo_cells_processed = 0;
 +/** How many CELL_VPADDING cells have we received, ever? */
 +uint64_t stats_n_vpadding_cells_processed = 0;
 +/** How many CELL_CERTS cells have we received, ever? */
 +uint64_t stats_n_certs_cells_processed = 0;
 +/** How many CELL_AUTH_CHALLENGE cells have we received, ever? */
 +uint64_t stats_n_auth_challenge_cells_processed = 0;
 +/** How many CELL_AUTHENTICATE cells have we received, ever? */
 +uint64_t stats_n_authenticate_cells_processed = 0;
 +/** How many CELL_AUTHORIZE cells have we received, ever? */
 +uint64_t stats_n_authorize_cells_processed = 0;
 +
 +/** Active listener, if any */
 +static channel_listener_t *channel_tls_listener = NULL;
 +
 +/* channel_tls_t method declarations */
 +
 +static void channel_tls_close_method(channel_t *chan);
 +static const char * channel_tls_describe_transport_method(channel_t *chan);
 +static void channel_tls_free_method(channel_t *chan);
 +static double channel_tls_get_overhead_estimate_method(channel_t *chan);
 +static int
 +channel_tls_get_remote_addr_method(channel_t *chan, tor_addr_t *addr_out);
 +static int
 +channel_tls_get_transport_name_method(channel_t *chan, char **transport_out);
 +static const char *
 +channel_tls_get_remote_descr_method(channel_t *chan, int flags);
 +static int channel_tls_has_queued_writes_method(channel_t *chan);
 +static int channel_tls_is_canonical_method(channel_t *chan, int req);
 +static int
 +channel_tls_matches_extend_info_method(channel_t *chan,
 +                                       extend_info_t *extend_info);
 +static int channel_tls_matches_target_method(channel_t *chan,
 +                                             const tor_addr_t *target);
 +static int channel_tls_num_cells_writeable_method(channel_t *chan);
 +static size_t channel_tls_num_bytes_queued_method(channel_t *chan);
 +static int channel_tls_write_cell_method(channel_t *chan,
 +                                         cell_t *cell);
 +static int channel_tls_write_packed_cell_method(channel_t *chan,
 +                                                packed_cell_t *packed_cell);
 +static int channel_tls_write_var_cell_method(channel_t *chan,
 +                                             var_cell_t *var_cell);
 +
 +/* channel_listener_tls_t method declarations */
 +
 +static void channel_tls_listener_close_method(channel_listener_t *chan_l);
 +static const char *
 +channel_tls_listener_describe_transport_method(channel_listener_t *chan_l);
 +
 +/** Handle incoming cells for the handshake stuff here rather than
 + * passing them on up. */
 +
 +static void channel_tls_process_versions_cell(var_cell_t *cell,
 +                                              channel_tls_t *tlschan);
 +static void channel_tls_process_netinfo_cell(cell_t *cell,
 +                                             channel_tls_t *tlschan);
 +static int command_allowed_before_handshake(uint8_t command);
 +static int enter_v3_handshake_with_cell(var_cell_t *cell,
 +                                        channel_tls_t *tlschan);
 +static void channel_tls_process_padding_negotiate_cell(cell_t *cell,
 +                                                       channel_tls_t *chan);
 +
 +/**
 + * Do parts of channel_tls_t initialization common to channel_tls_connect()
 + * and channel_tls_handle_incoming().
 + */
 +STATIC void
 +channel_tls_common_init(channel_tls_t *tlschan)
 +{
 +  channel_t *chan;
 +
 +  tor_assert(tlschan);
 +
 +  chan = &(tlschan->base_);
 +  channel_init(chan);
 +  chan->magic = TLS_CHAN_MAGIC;
 +  chan->state = CHANNEL_STATE_OPENING;
 +  chan->close = channel_tls_close_method;
 +  chan->describe_transport = channel_tls_describe_transport_method;
 +  chan->free_fn = channel_tls_free_method;
 +  chan->get_overhead_estimate = channel_tls_get_overhead_estimate_method;
 +  chan->get_remote_addr = channel_tls_get_remote_addr_method;
 +  chan->get_remote_descr = channel_tls_get_remote_descr_method;
 +  chan->get_transport_name = channel_tls_get_transport_name_method;
 +  chan->has_queued_writes = channel_tls_has_queued_writes_method;
 +  chan->is_canonical = channel_tls_is_canonical_method;
 +  chan->matches_extend_info = channel_tls_matches_extend_info_method;
 +  chan->matches_target = channel_tls_matches_target_method;
 +  chan->num_bytes_queued = channel_tls_num_bytes_queued_method;
 +  chan->num_cells_writeable = channel_tls_num_cells_writeable_method;
 +  chan->write_cell = channel_tls_write_cell_method;
 +  chan->write_packed_cell = channel_tls_write_packed_cell_method;
 +  chan->write_var_cell = channel_tls_write_var_cell_method;
 +
 +  chan->cmux = circuitmux_alloc();
 +  /* We only have one policy for now so always set it to EWMA. */
 +  circuitmux_set_policy(chan->cmux, &ewma_policy);
 +}
 +
 +/**
 + * Start a new TLS channel.
 + *
 + * Launch a new OR connection to <b>addr</b>:<b>port</b> and expect to
 + * handshake with an OR with identity digest <b>id_digest</b>, and wrap
 + * it in a channel_tls_t.
 + */
 +channel_t *
 +channel_tls_connect(const tor_addr_t *addr, uint16_t port,
 +                    const char *id_digest,
 +                    const ed25519_public_key_t *ed_id)
 +{
 +  channel_tls_t *tlschan = tor_malloc_zero(sizeof(*tlschan));
 +  channel_t *chan = &(tlschan->base_);
 +
 +  channel_tls_common_init(tlschan);
 +
 +  log_debug(LD_CHANNEL,
 +            "In channel_tls_connect() for channel %p "
 +            "(global id %"PRIu64 ")",
 +            tlschan,
 +            (chan->global_identifier));
 +
 +  if (is_local_addr(addr)) {
 +    log_debug(LD_CHANNEL,
 +              "Marking new outgoing channel %"PRIu64 " at %p as local",
 +              (chan->global_identifier), chan);
 +    channel_mark_local(chan);
 +  } else {
 +    log_debug(LD_CHANNEL,
 +              "Marking new outgoing channel %"PRIu64 " at %p as remote",
 +              (chan->global_identifier), chan);
 +    channel_mark_remote(chan);
 +  }
 +
 +  channel_mark_outgoing(chan);
 +
 +  /* Set up or_connection stuff */
 +  tlschan->conn = connection_or_connect(addr, port, id_digest, ed_id, tlschan);
 +  /* connection_or_connect() will fill in tlschan->conn */
 +  if (!(tlschan->conn)) {
 +    chan->reason_for_closing = CHANNEL_CLOSE_FOR_ERROR;
 +    channel_change_state(chan, CHANNEL_STATE_ERROR);
 +    goto err;
 +  }
 +
 +  log_debug(LD_CHANNEL,
 +            "Got orconn %p for channel with global id %"PRIu64,
 +            tlschan->conn, (chan->global_identifier));
 +
 +  goto done;
 +
 + err:
 +  circuitmux_free(chan->cmux);
 +  tor_free(tlschan);
 +  chan = NULL;
 +
 + done:
 +  /* If we got one, we should register it */
 +  if (chan) channel_register(chan);
 +
 +  return chan;
 +}
 +
 +/**
 + * Return the current channel_tls_t listener.
 + *
 + * Returns the current channel listener for incoming TLS connections, or
 + * NULL if none has been established
 + */
 +channel_listener_t *
 +channel_tls_get_listener(void)
 +{
 +  return channel_tls_listener;
 +}
 +
 +/**
 + * Start a channel_tls_t listener if necessary.
 + *
 + * Return the current channel_tls_t listener, or start one if we haven't yet,
 + * and return that.
 + */
 +channel_listener_t *
 +channel_tls_start_listener(void)
 +{
 +  channel_listener_t *listener;
 +
 +  if (!channel_tls_listener) {
 +    listener = tor_malloc_zero(sizeof(*listener));
 +    channel_init_listener(listener);
 +    listener->state = CHANNEL_LISTENER_STATE_LISTENING;
 +    listener->close = channel_tls_listener_close_method;
 +    listener->describe_transport =
 +      channel_tls_listener_describe_transport_method;
 +
 +    channel_tls_listener = listener;
 +
 +    log_debug(LD_CHANNEL,
 +              "Starting TLS channel listener %p with global id %"PRIu64,
 +              listener, (listener->global_identifier));
 +
 +    channel_listener_register(listener);
 +  } else listener = channel_tls_listener;
 +
 +  return listener;
 +}
 +
 +/**
 + * Free everything on shutdown.
 + *
 + * Not much to do here, since channel_free_all() takes care of a lot, but let's
 + * get rid of the listener.
 + */
 +void
 +channel_tls_free_all(void)
 +{
 +  channel_listener_t *old_listener = NULL;
 +
 +  log_debug(LD_CHANNEL,
 +            "Shutting down TLS channels...");
 +
 +  if (channel_tls_listener) {
 +    /*
 +     * When we close it, channel_tls_listener will get nulled out, so save
 +     * a pointer so we can free it.
 +     */
 +    old_listener = channel_tls_listener;
 +    log_debug(LD_CHANNEL,
 +              "Closing channel_tls_listener with ID %"PRIu64
 +              " at %p.",
 +              (old_listener->global_identifier),
 +              old_listener);
 +    channel_listener_unregister(old_listener);
 +    channel_listener_mark_for_close(old_listener);
 +    channel_listener_free(old_listener);
 +    tor_assert(channel_tls_listener == NULL);
 +  }
 +
 +  log_debug(LD_CHANNEL,
 +            "Done shutting down TLS channels");
 +}
 +
 +/**
 + * Create a new channel around an incoming or_connection_t.
 + */
 +channel_t *
 +channel_tls_handle_incoming(or_connection_t *orconn)
 +{
 +  channel_tls_t *tlschan = tor_malloc_zero(sizeof(*tlschan));
 +  channel_t *chan = &(tlschan->base_);
 +
 +  tor_assert(orconn);
 +  tor_assert(!(orconn->chan));
 +
 +  channel_tls_common_init(tlschan);
 +
 +  /* Link the channel and orconn to each other */
 +  tlschan->conn = orconn;
 +  orconn->chan = tlschan;
 +
 +  if (is_local_addr(&(TO_CONN(orconn)->addr))) {
 +    log_debug(LD_CHANNEL,
 +              "Marking new incoming channel %"PRIu64 " at %p as local",
 +              (chan->global_identifier), chan);
 +    channel_mark_local(chan);
 +  } else {
 +    log_debug(LD_CHANNEL,
 +              "Marking new incoming channel %"PRIu64 " at %p as remote",
 +              (chan->global_identifier), chan);
 +    channel_mark_remote(chan);
 +  }
 +
 +  channel_mark_incoming(chan);
 +
 +  /* Register it */
 +  channel_register(chan);
 +
 +  return chan;
 +}
 +
 +/*********
 + * Casts *
 + ********/
 +
 +/**
 + * Cast a channel_tls_t to a channel_t.
 + */
 +channel_t *
 +channel_tls_to_base(channel_tls_t *tlschan)
 +{
 +  if (!tlschan) return NULL;
 +
 +  return &(tlschan->base_);
 +}
 +
 +/**
 + * Cast a channel_t to a channel_tls_t, with appropriate type-checking
 + * asserts.
 + */
 +channel_tls_t *
 +channel_tls_from_base(channel_t *chan)
 +{
 +  if (!chan) return NULL;
 +
 +  tor_assert(chan->magic == TLS_CHAN_MAGIC);
 +
 +  return (channel_tls_t *)(chan);
 +}
 +
 +/********************************************
 + * Method implementations for channel_tls_t *
 + *******************************************/
 +
 +/**
 + * Close a channel_tls_t.
 + *
 + * This implements the close method for channel_tls_t.
 + */
 +static void
 +channel_tls_close_method(channel_t *chan)
 +{
 +  channel_tls_t *tlschan = BASE_CHAN_TO_TLS(chan);
 +
 +  tor_assert(tlschan);
 +
 +  if (tlschan->conn) connection_or_close_normally(tlschan->conn, 1);
 +  else {
 +    /* Weird - we'll have to change the state ourselves, I guess */
 +    log_info(LD_CHANNEL,
 +             "Tried to close channel_tls_t %p with NULL conn",
 +             tlschan);
 +    channel_change_state(chan, CHANNEL_STATE_ERROR);
 +  }
 +}
 +
 +/**
 + * Describe the transport for a channel_tls_t.
 + *
 + * This returns the string "TLS channel on connection <id>" to the upper
 + * layer.
 + */
 +static const char *
 +channel_tls_describe_transport_method(channel_t *chan)
 +{
 +  static char *buf = NULL;
 +  uint64_t id;
 +  channel_tls_t *tlschan;
 +  const char *rv = NULL;
 +
 +  tor_assert(chan);
 +
 +  tlschan = BASE_CHAN_TO_TLS(chan);
 +
 +  if (tlschan->conn) {
 +    id = TO_CONN(tlschan->conn)->global_identifier;
 +
 +    if (buf) tor_free(buf);
 +    tor_asprintf(&buf,
 +                 "TLS channel (connection %"PRIu64 ")",
 +                 (id));
 +
 +    rv = buf;
 +  } else {
 +    rv = "TLS channel (no connection)";
 +  }
 +
 +  return rv;
 +}
 +
 +/**
 + * Free a channel_tls_t.
 + *
 + * This is called by the generic channel layer when freeing a channel_tls_t;
 + * this happens either on a channel which has already reached
 + * CHANNEL_STATE_CLOSED or CHANNEL_STATE_ERROR from channel_run_cleanup() or
 + * on shutdown from channel_free_all().  In the latter case we might still
 + * have an orconn active (which connection_free_all() will get to later),
 + * so we should null out its channel pointer now.
 + */
 +static void
 +channel_tls_free_method(channel_t *chan)
 +{
 +  channel_tls_t *tlschan = BASE_CHAN_TO_TLS(chan);
 +
 +  tor_assert(tlschan);
 +
 +  if (tlschan->conn) {
 +    tlschan->conn->chan = NULL;
 +    tlschan->conn = NULL;
 +  }
 +}
 +
 +/**
 + * Get an estimate of the average TLS overhead for the upper layer.
 + */
 +static double
 +channel_tls_get_overhead_estimate_method(channel_t *chan)
 +{
 +  double overhead = 1.0;
 +  channel_tls_t *tlschan = BASE_CHAN_TO_TLS(chan);
 +
 +  tor_assert(tlschan);
 +  tor_assert(tlschan->conn);
 +
 +  /* Just return 1.0f if we don't have sensible data */
 +  if (tlschan->conn->bytes_xmitted > 0 &&
 +      tlschan->conn->bytes_xmitted_by_tls >=
 +      tlschan->conn->bytes_xmitted) {
 +    overhead = ((double)(tlschan->conn->bytes_xmitted_by_tls)) /
 +      ((double)(tlschan->conn->bytes_xmitted));
 +
 +    /*
 +     * Never estimate more than 2.0; otherwise we get silly large estimates
 +     * at the very start of a new TLS connection.
 +     */
 +    if (overhead > 2.0)
 +      overhead = 2.0;
 +  }
 +
 +  log_debug(LD_CHANNEL,
 +            "Estimated overhead ratio for TLS chan %"PRIu64 " is %f",
 +            (chan->global_identifier), overhead);
 +
 +  return overhead;
 +}
 +
 +/**
 + * Get the remote address of a channel_tls_t.
 + *
 + * This implements the get_remote_addr method for channel_tls_t; copy the
 + * remote endpoint of the channel to addr_out and return 1 (always
 + * succeeds for this transport).
 + */
 +static int
 +channel_tls_get_remote_addr_method(channel_t *chan, tor_addr_t *addr_out)
 +{
 +  int rv = 0;
 +  channel_tls_t *tlschan = BASE_CHAN_TO_TLS(chan);
 +
 +  tor_assert(tlschan);
 +  tor_assert(addr_out);
 +
 +  if (tlschan->conn) {
 +    tor_addr_copy(addr_out, &(tlschan->conn->real_addr));
 +    rv = 1;
 +  } else tor_addr_make_unspec(addr_out);
 +
 +  return rv;
 +}
 +
 +/**
 + * Get the name of the pluggable transport used by a channel_tls_t.
 + *
 + * This implements the get_transport_name for channel_tls_t. If the
 + * channel uses a pluggable transport, copy its name to
 + * <b>transport_out</b> and return 0. If the channel did not use a
 + * pluggable transport, return -1.
 + */
 +static int
 +channel_tls_get_transport_name_method(channel_t *chan, char **transport_out)
 +{
 +  channel_tls_t *tlschan = BASE_CHAN_TO_TLS(chan);
 +
 +  tor_assert(tlschan);
 +  tor_assert(transport_out);
 +  tor_assert(tlschan->conn);
 +
 +  if (!tlschan->conn->ext_or_transport)
 +    return -1;
 +
 +  *transport_out = tor_strdup(tlschan->conn->ext_or_transport);
 +  return 0;
 +}
 +
 +/**
 + * Get endpoint description of a channel_tls_t.
 + *
 + * This implements the get_remote_descr method for channel_tls_t; it returns
 + * a text description of the remote endpoint of the channel suitable for use
 + * in log messages. The req parameter is 0 for the canonical address or 1 for
 + * the actual address seen.
 + */
 +static const char *
 +channel_tls_get_remote_descr_method(channel_t *chan, int flags)
 +{
 +#define MAX_DESCR_LEN 32
 +
 +  static char buf[MAX_DESCR_LEN + 1];
 +  channel_tls_t *tlschan = BASE_CHAN_TO_TLS(chan);
 +  connection_t *conn;
 +  const char *answer = NULL;
 +  char *addr_str;
 +
 +  tor_assert(tlschan);
 +
 +  if (tlschan->conn) {
 +    conn = TO_CONN(tlschan->conn);
 +    switch (flags) {
 +      case 0:
 +        /* Canonical address with port*/
 +        tor_snprintf(buf, MAX_DESCR_LEN + 1,
 +                     "%s:%u", conn->address, conn->port);
 +        answer = buf;
 +        break;
 +      case GRD_FLAG_ORIGINAL:
 +        /* Actual address with port */
 +        addr_str = tor_addr_to_str_dup(&(tlschan->conn->real_addr));
 +        tor_snprintf(buf, MAX_DESCR_LEN + 1,
 +                     "%s:%u", addr_str, conn->port);
 +        tor_free(addr_str);
 +        answer = buf;
 +        break;
 +      case GRD_FLAG_ADDR_ONLY:
 +        /* Canonical address, no port */
 +        strlcpy(buf, conn->address, sizeof(buf));
 +        answer = buf;
 +        break;
 +      case GRD_FLAG_ORIGINAL|GRD_FLAG_ADDR_ONLY:
 +        /* Actual address, no port */
 +        addr_str = tor_addr_to_str_dup(&(tlschan->conn->real_addr));
 +        strlcpy(buf, addr_str, sizeof(buf));
 +        tor_free(addr_str);
 +        answer = buf;
 +        break;
 +      default:
 +        /* Something's broken in channel.c */
 +        tor_assert_nonfatal_unreached_once();
 +    }
 +  } else {
 +    strlcpy(buf, "(No connection)", sizeof(buf));
 +    answer = buf;
 +  }
 +
 +  return answer;
 +}
 +
 +/**
 + * Tell the upper layer if we have queued writes.
 + *
 + * This implements the has_queued_writes method for channel_tls t_; it returns
 + * 1 iff we have queued writes on the outbuf of the underlying or_connection_t.
 + */
 +static int
 +channel_tls_has_queued_writes_method(channel_t *chan)
 +{
 +  size_t outbuf_len;
 +  channel_tls_t *tlschan = BASE_CHAN_TO_TLS(chan);
 +
 +  tor_assert(tlschan);
 +  if (!(tlschan->conn)) {
 +    log_info(LD_CHANNEL,
 +             "something called has_queued_writes on a tlschan "
 +             "(%p with ID %"PRIu64 " but no conn",
 +             chan, (chan->global_identifier));
 +  }
 +
 +  outbuf_len = (tlschan->conn != NULL) ?
 +    connection_get_outbuf_len(TO_CONN(tlschan->conn)) :
 +    0;
 +
 +  return (outbuf_len > 0);
 +}
 +
 +/**
 + * Tell the upper layer if we're canonical.
 + *
 + * This implements the is_canonical method for channel_tls_t; if req is zero,
 + * it returns whether this is a canonical channel, and if it is one it returns
 + * whether that can be relied upon.
 + */
 +static int
 +channel_tls_is_canonical_method(channel_t *chan, int req)
 +{
 +  int answer = 0;
 +  channel_tls_t *tlschan = BASE_CHAN_TO_TLS(chan);
 +
 +  tor_assert(tlschan);
 +
 +  if (tlschan->conn) {
 +    switch (req) {
 +      case 0:
 +        answer = tlschan->conn->is_canonical;
 +        break;
 +      case 1:
 +        /*
 +         * Is the is_canonical bit reliable?  In protocols version 2 and up
 +         * we get the canonical address from a NETINFO cell, but in older
 +         * versions it might be based on an obsolete descriptor.
 +         */
 +        answer = (tlschan->conn->link_proto >= 2);
 +        break;
 +      default:
 +        /* This shouldn't happen; channel.c is broken if it does */
 +        tor_assert_nonfatal_unreached_once();
 +    }
 +  }
 +  /* else return 0 for tlschan->conn == NULL */
 +
 +  return answer;
 +}
 +
 +/**
 + * Check if we match an extend_info_t.
 + *
 + * This implements the matches_extend_info method for channel_tls_t; the upper
 + * layer wants to know if this channel matches an extend_info_t.
 + */
 +static int
 +channel_tls_matches_extend_info_method(channel_t *chan,
 +                                       extend_info_t *extend_info)
 +{
 +  channel_tls_t *tlschan = BASE_CHAN_TO_TLS(chan);
 +
 +  tor_assert(tlschan);
 +  tor_assert(extend_info);
 +
 +  /* Never match if we have no conn */
 +  if (!(tlschan->conn)) {
 +    log_info(LD_CHANNEL,
 +             "something called matches_extend_info on a tlschan "
 +             "(%p with ID %"PRIu64 " but no conn",
 +             chan, (chan->global_identifier));
 +    return 0;
 +  }
 +
 +  return (tor_addr_eq(&(extend_info->addr),
 +                      &(TO_CONN(tlschan->conn)->addr)) &&
 +         (extend_info->port == TO_CONN(tlschan->conn)->port));
 +}
 +
 +/**
 + * Check if we match a target address; return true iff we do.
 + *
 + * This implements the matches_target method for channel_tls t_; the upper
 + * layer wants to know if this channel matches a target address when extending
 + * a circuit.
 + */
 +static int
 +channel_tls_matches_target_method(channel_t *chan,
 +                                  const tor_addr_t *target)
 +{
 +  channel_tls_t *tlschan = BASE_CHAN_TO_TLS(chan);
 +
 +  tor_assert(tlschan);
 +  tor_assert(target);
 +
 +  /* Never match if we have no conn */
 +  if (!(tlschan->conn)) {
 +    log_info(LD_CHANNEL,
 +             "something called matches_target on a tlschan "
 +             "(%p with ID %"PRIu64 " but no conn",
 +             chan, (chan->global_identifier));
 +    return 0;
 +  }
 +
 +  /* real_addr is the address this connection came from.
 +   * base_.addr is updated by connection_or_init_conn_from_address()
 +   * to be the address in the descriptor. It may be tempting to
 +   * allow either address to be allowed, but if we did so, it would
 +   * enable someone who steals a relay's keys to impersonate/MITM it
 +   * from anywhere on the Internet! (Because they could make long-lived
 +   * TLS connections from anywhere to all relays, and wait for them to
 +   * be used for extends).
 +   */
 +  return tor_addr_eq(&(tlschan->conn->real_addr), target);
 +}
 +
 +/**
 + * Tell the upper layer how many bytes we have queued and not yet
 + * sent.
 + */
 +static size_t
 +channel_tls_num_bytes_queued_method(channel_t *chan)
 +{
 +  channel_tls_t *tlschan = BASE_CHAN_TO_TLS(chan);
 +
 +  tor_assert(tlschan);
 +  tor_assert(tlschan->conn);
 +
 +  return connection_get_outbuf_len(TO_CONN(tlschan->conn));
 +}
 +
 +/**
 + * Tell the upper layer how many cells we can accept to write.
 + *
 + * This implements the num_cells_writeable method for channel_tls_t; it
 + * returns an estimate of the number of cells we can accept with
 + * channel_tls_write_*_cell().
 + */
 +static int
 +channel_tls_num_cells_writeable_method(channel_t *chan)
 +{
 +  size_t outbuf_len;
 +  ssize_t n;
 +  channel_tls_t *tlschan = BASE_CHAN_TO_TLS(chan);
 +  size_t cell_network_size;
 +
 +  tor_assert(tlschan);
 +  tor_assert(tlschan->conn);
 +
 +  cell_network_size = get_cell_network_size(tlschan->conn->wide_circ_ids);
 +  outbuf_len = connection_get_outbuf_len(TO_CONN(tlschan->conn));
 +  /* Get the number of cells */
 +  n = CEIL_DIV(OR_CONN_HIGHWATER - outbuf_len, cell_network_size);
 +  if (n < 0) n = 0;
 +#if SIZEOF_SIZE_T > SIZEOF_INT
 +  if (n > INT_MAX) n = INT_MAX;
 +#endif
 +
 +  return (int)n;
 +}
 +
 +/**
 + * Write a cell to a channel_tls_t.
 + *
 + * This implements the write_cell method for channel_tls_t; given a
 + * channel_tls_t and a cell_t, transmit the cell_t.
 + */
 +static int
 +channel_tls_write_cell_method(channel_t *chan, cell_t *cell)
 +{
 +  channel_tls_t *tlschan = BASE_CHAN_TO_TLS(chan);
 +  int written = 0;
 +
 +  tor_assert(tlschan);
 +  tor_assert(cell);
 +
 +  if (tlschan->conn) {
 +    connection_or_write_cell_to_buf(cell, tlschan->conn);
 +    ++written;
 +  } else {
 +    log_info(LD_CHANNEL,
 +             "something called write_cell on a tlschan "
 +             "(%p with ID %"PRIu64 " but no conn",
 +             chan, (chan->global_identifier));
 +  }
 +
 +  return written;
 +}
 +
 +/**
 + * Write a packed cell to a channel_tls_t.
 + *
 + * This implements the write_packed_cell method for channel_tls_t; given a
 + * channel_tls_t and a packed_cell_t, transmit the packed_cell_t.
 + *
 + * Return 0 on success or negative value on error. The caller must free the
 + * packed cell.
 + */
 +static int
 +channel_tls_write_packed_cell_method(channel_t *chan,
 +                                     packed_cell_t *packed_cell)
 +{
 +  tor_assert(chan);
 +  channel_tls_t *tlschan = BASE_CHAN_TO_TLS(chan);
 +  size_t cell_network_size = get_cell_network_size(chan->wide_circ_ids);
 +
 +  tor_assert(tlschan);
 +  tor_assert(packed_cell);
 +
 +  if (tlschan->conn) {
 +    connection_buf_add(packed_cell->body, cell_network_size,
 +                            TO_CONN(tlschan->conn));
 +  } else {
 +    log_info(LD_CHANNEL,
 +             "something called write_packed_cell on a tlschan "
 +             "(%p with ID %"PRIu64 " but no conn",
 +             chan, (chan->global_identifier));
 +    return -1;
 +  }
 +
 +  return 0;
 +}
 +
 +/**
 + * Write a variable-length cell to a channel_tls_t.
 + *
 + * This implements the write_var_cell method for channel_tls_t; given a
 + * channel_tls_t and a var_cell_t, transmit the var_cell_t.
 + */
 +static int
 +channel_tls_write_var_cell_method(channel_t *chan, var_cell_t *var_cell)
 +{
 +  channel_tls_t *tlschan = BASE_CHAN_TO_TLS(chan);
 +  int written = 0;
 +
 +  tor_assert(tlschan);
 +  tor_assert(var_cell);
 +
 +  if (tlschan->conn) {
 +    connection_or_write_var_cell_to_buf(var_cell, tlschan->conn);
 +    ++written;
 +  } else {
 +    log_info(LD_CHANNEL,
 +             "something called write_var_cell on a tlschan "
 +             "(%p with ID %"PRIu64 " but no conn",
 +             chan, (chan->global_identifier));
 +  }
 +
 +  return written;
 +}
 +
 +/*************************************************
 + * Method implementations for channel_listener_t *
 + ************************************************/
 +
 +/**
 + * Close a channel_listener_t.
 + *
 + * This implements the close method for channel_listener_t.
 + */
 +static void
 +channel_tls_listener_close_method(channel_listener_t *chan_l)
 +{
 +  tor_assert(chan_l);
 +
 +  /*
 +   * Listeners we just go ahead and change state through to CLOSED, but
 +   * make sure to check if they're channel_tls_listener to NULL it out.
 +   */
 +  if (chan_l == channel_tls_listener)
 +    channel_tls_listener = NULL;
 +
 +  if (!(chan_l->state == CHANNEL_LISTENER_STATE_CLOSING ||
 +        chan_l->state == CHANNEL_LISTENER_STATE_CLOSED ||
 +        chan_l->state == CHANNEL_LISTENER_STATE_ERROR)) {
 +    channel_listener_change_state(chan_l, CHANNEL_LISTENER_STATE_CLOSING);
 +  }
 +
 +  if (chan_l->incoming_list) {
 +    SMARTLIST_FOREACH_BEGIN(chan_l->incoming_list,
 +                            channel_t *, ichan) {
 +      channel_mark_for_close(ichan);
 +    } SMARTLIST_FOREACH_END(ichan);
 +
 +    smartlist_free(chan_l->incoming_list);
 +    chan_l->incoming_list = NULL;
 +  }
 +
 +  if (!(chan_l->state == CHANNEL_LISTENER_STATE_CLOSED ||
 +        chan_l->state == CHANNEL_LISTENER_STATE_ERROR)) {
 +    channel_listener_change_state(chan_l, CHANNEL_LISTENER_STATE_CLOSED);
 +  }
 +}
 +
 +/**
 + * Describe the transport for a channel_listener_t.
 + *
 + * This returns the string "TLS channel (listening)" to the upper
 + * layer.
 + */
 +static const char *
 +channel_tls_listener_describe_transport_method(channel_listener_t *chan_l)
 +{
 +  tor_assert(chan_l);
 +
 +  return "TLS channel (listening)";
 +}
 +
 +/*******************************************************
 + * Functions for handling events on an or_connection_t *
 + ******************************************************/
 +
 +/**
 + * Handle an orconn state change.
 + *
 + * This function will be called by connection_or.c when the or_connection_t
 + * associated with this channel_tls_t changes state.
 + */
 +void
 +channel_tls_handle_state_change_on_orconn(channel_tls_t *chan,
 +                                          or_connection_t *conn,
 +                                          uint8_t old_state,
 +                                          uint8_t state)
 +{
 +  channel_t *base_chan;
 +
 +  tor_assert(chan);
 +  tor_assert(conn);
 +  tor_assert(conn->chan == chan);
 +  tor_assert(chan->conn == conn);
 +  /* Shut the compiler up without triggering -Wtautological-compare */
 +  (void)old_state;
 +
 +  base_chan = TLS_CHAN_TO_BASE(chan);
 +
 +  /* Make sure the base connection state makes sense - shouldn't be error
 +   * or closed. */
 +
 +  tor_assert(CHANNEL_IS_OPENING(base_chan) ||
 +             CHANNEL_IS_OPEN(base_chan) ||
 +             CHANNEL_IS_MAINT(base_chan) ||
 +             CHANNEL_IS_CLOSING(base_chan));
 +
 +  /* Did we just go to state open? */
 +  if (state == OR_CONN_STATE_OPEN) {
 +    /*
 +     * We can go to CHANNEL_STATE_OPEN from CHANNEL_STATE_OPENING or
 +     * CHANNEL_STATE_MAINT on this.
 +     */
 +    channel_change_state_open(base_chan);
 +    /* We might have just become writeable; check and tell the scheduler */
 +    if (connection_or_num_cells_writeable(conn) > 0) {
 +      scheduler_channel_wants_writes(base_chan);
 +    }
 +  } else {
 +    /*
 +     * Not open, so from CHANNEL_STATE_OPEN we go to CHANNEL_STATE_MAINT,
 +     * otherwise no change.
 +     */
 +    if (CHANNEL_IS_OPEN(base_chan)) {
 +      channel_change_state(base_chan, CHANNEL_STATE_MAINT);
 +    }
 +  }
 +}
 +
 +#ifdef KEEP_TIMING_STATS
 +
 +/**
 + * Timing states wrapper.
 + *
 + * This is a wrapper function around the actual function that processes the
 + * <b>cell</b> that just arrived on <b>chan</b>. Increment <b>*time</b>
 + * by the number of microseconds used by the call to <b>*func(cell, chan)</b>.
 + */
 +static void
 +channel_tls_time_process_cell(cell_t *cell, channel_tls_t *chan, int *time,
 +                              void (*func)(cell_t *, channel_tls_t *))
 +{
 +  struct timeval start, end;
 +  long time_passed;
 +
 +  tor_gettimeofday(&start);
 +
 +  (*func)(cell, chan);
 +
 +  tor_gettimeofday(&end);
 +  time_passed = tv_udiff(&start, &end) ;
 +
 +  if (time_passed > 10000) { /* more than 10ms */
 +    log_debug(LD_OR,"That call just took %ld ms.",time_passed/1000);
 +  }
 +
 +  if (time_passed < 0) {
 +    log_info(LD_GENERAL,"That call took us back in time!");
 +    time_passed = 0;
 +  }
 +
 +  *time += time_passed;
 +}
 +#endif /* defined(KEEP_TIMING_STATS) */
 +
 +/**
 + * Handle an incoming cell on a channel_tls_t.
 + *
 + * This is called from connection_or.c to handle an arriving cell; it checks
 + * for cell types specific to the handshake for this transport protocol and
 + * handles them, and queues all other cells to the channel_t layer, which
 + * eventually will hand them off to command.c.
 + *
 + * The channel layer itself decides whether the cell should be queued or
 + * can be handed off immediately to the upper-layer code.  It is responsible
 + * for copying in the case that it queues; we merely pass pointers through
 + * which we get from connection_or_process_cells_from_inbuf().
 + */
 +void
 +channel_tls_handle_cell(cell_t *cell, or_connection_t *conn)
 +{
 +  channel_tls_t *chan;
 +  int handshaking;
 +
 +#ifdef KEEP_TIMING_STATS
 +#define PROCESS_CELL(tp, cl, cn) STMT_BEGIN {                   \
 +    ++num ## tp;                                                \
 +    channel_tls_time_process_cell(cl, cn, & tp ## time ,            \
 +                             channel_tls_process_ ## tp ## _cell);  \
 +    } STMT_END
 +#else /* !(defined(KEEP_TIMING_STATS)) */
 +#define PROCESS_CELL(tp, cl, cn) channel_tls_process_ ## tp ## _cell(cl, cn)
 +#endif /* defined(KEEP_TIMING_STATS) */
 +
 +  tor_assert(cell);
 +  tor_assert(conn);
 +
 +  chan = conn->chan;
 +
 + if (!chan) {
 +   log_warn(LD_CHANNEL,
 +            "Got a cell_t on an OR connection with no channel");
 +   return;
 +  }
 +
 +  handshaking = (TO_CONN(conn)->state != OR_CONN_STATE_OPEN);
 +
 +  if (conn->base_.marked_for_close)
 +    return;
 +
 +  /* Reject all but VERSIONS and NETINFO when handshaking. */
 +  /* (VERSIONS should actually be impossible; it's variable-length.) */
 +  if (handshaking && cell->command != CELL_VERSIONS &&
 +      cell->command != CELL_NETINFO) {
 +    log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
 +           "Received unexpected cell command %d in chan state %s / "
 +           "conn state %s; closing the connection.",
 +           (int)cell->command,
 +           channel_state_to_string(TLS_CHAN_TO_BASE(chan)->state),
 +           conn_state_to_string(CONN_TYPE_OR, TO_CONN(conn)->state));
 +    connection_or_close_for_error(conn, 0);
 +    return;
 +  }
 +
 +  if (conn->base_.state == OR_CONN_STATE_OR_HANDSHAKING_V3)
 +    or_handshake_state_record_cell(conn, conn->handshake_state, cell, 1);
 +
 +  /* We note that we're on the internet whenever we read a cell. This is
 +   * a fast operation. */
 +  entry_guards_note_internet_connectivity(get_guard_selection_info());
 +  rep_hist_padding_count_read(PADDING_TYPE_TOTAL);
 +
 +  if (TLS_CHAN_TO_BASE(chan)->currently_padding)
 +    rep_hist_padding_count_read(PADDING_TYPE_ENABLED_TOTAL);
 +
 +  switch (cell->command) {
 +    case CELL_PADDING:
 +      rep_hist_padding_count_read(PADDING_TYPE_CELL);
 +      if (TLS_CHAN_TO_BASE(chan)->currently_padding)
 +        rep_hist_padding_count_read(PADDING_TYPE_ENABLED_CELL);
 +      ++stats_n_padding_cells_processed;
 +      /* do nothing */
 +      break;
 +    case CELL_VERSIONS:
-       tor_fragile_assert();
++      /* A VERSIONS cell should always be a variable-length cell, and
++       * so should never reach this function (which handles constant-sized
++       * cells). But if the connection is using the (obsolete) v1 link
++       * protocol, all cells will be treated as constant-sized, and so
++       * it's possible we'll reach this code.
++       */
++      log_fn(LOG_PROTOCOL_WARN, LD_CHANNEL,
++             "Received unexpected VERSIONS cell on a channel using link "
++             "protocol %d; ignoring.", conn->link_proto);
 +      break;
 +    case CELL_NETINFO:
 +      ++stats_n_netinfo_cells_processed;
 +      PROCESS_CELL(netinfo, cell, chan);
 +      break;
 +    case CELL_PADDING_NEGOTIATE:
 +      ++stats_n_netinfo_cells_processed;
 +      PROCESS_CELL(padding_negotiate, cell, chan);
 +      break;
 +    case CELL_CREATE:
 +    case CELL_CREATE_FAST:
 +    case CELL_CREATED:
 +    case CELL_CREATED_FAST:
 +    case CELL_RELAY:
 +    case CELL_RELAY_EARLY:
 +    case CELL_DESTROY:
 +    case CELL_CREATE2:
 +    case CELL_CREATED2:
 +      /*
 +       * These are all transport independent and we pass them up through the
 +       * channel_t mechanism.  They are ultimately handled in command.c.
 +       */
 +      channel_process_cell(TLS_CHAN_TO_BASE(chan), cell);
 +      break;
 +    default:
 +      log_fn(LOG_INFO, LD_PROTOCOL,
 +             "Cell of unknown type (%d) received in channeltls.c.  "
 +             "Dropping.",
 +             cell->command);
 +             break;
 +  }
 +}
 +
 +/**
 + * Handle an incoming variable-length cell on a channel_tls_t.
 + *
 + * Process a <b>var_cell</b> that was just received on <b>conn</b>. Keep
 + * internal statistics about how many of each cell we've processed so far
 + * this second, and the total number of microseconds it took to
 + * process each type of cell.  All the var_cell commands are handshake-
 + * related and live below the channel_t layer, so no variable-length
 + * cells ever get delivered in the current implementation, but I've left
 + * the mechanism in place for future use.
 + *
 + * If we were handing them off to the upper layer, the channel_t queueing
 + * code would be responsible for memory management, and we'd just be passing
 + * pointers through from connection_or_process_cells_from_inbuf().  That
 + * caller always frees them after this function returns, so this function
 + * should never free var_cell.
 + */
 +void
 +channel_tls_handle_var_cell(var_cell_t *var_cell, or_connection_t *conn)
 +{
 +  channel_tls_t *chan;
 +
 +#ifdef KEEP_TIMING_STATS
 +  /* how many of each cell have we seen so far this second? needs better
 +   * name. */
 +  static int num_versions = 0, num_certs = 0;
 +  static time_t current_second = 0; /* from previous calls to time */
 +  time_t now = time(NULL);
 +
 +  if (current_second == 0) current_second = now;
 +  if (now > current_second) { /* the second has rolled over */
 +    /* print stats */
 +    log_info(LD_OR,
 +             "At end of second: %d versions (%d ms), %d certs (%d ms)",
 +             num_versions, versions_time / ((now - current_second) * 1000),
 +             num_certs, certs_time / ((now - current_second) * 1000));
 +
 +    num_versions = num_certs = 0;
 +    versions_time = certs_time = 0;
 +
 +    /* remember which second it is, for next time */
 +    current_second = now;
 +  }
 +#endif /* defined(KEEP_TIMING_STATS) */
 +
 +  tor_assert(var_cell);
 +  tor_assert(conn);
 +
 +  chan = conn->chan;
 +
 +  if (!chan) {
 +    log_warn(LD_CHANNEL,
 +             "Got a var_cell_t on an OR connection with no channel");
 +    return;
 +  }
 +
 +  if (TO_CONN(conn)->marked_for_close)
 +    return;
 +
 +  switch (TO_CONN(conn)->state) {
 +    case OR_CONN_STATE_OR_HANDSHAKING_V2:
 +      if (var_cell->command != CELL_VERSIONS) {
 +        log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
 +               "Received a cell with command %d in unexpected "
 +               "orconn state "%s" [%d], channel state "%s" [%d]; "
 +               "closing the connection.",
 +               (int)(var_cell->command),
 +               conn_state_to_string(CONN_TYPE_OR, TO_CONN(conn)->state),
 +               TO_CONN(conn)->state,
 +               channel_state_to_string(TLS_CHAN_TO_BASE(chan)->state),
 +               (int)(TLS_CHAN_TO_BASE(chan)->state));
 +        /*
 +         * The code in connection_or.c will tell channel_t to close for
 +         * error; it will go to CHANNEL_STATE_CLOSING, and then to
 +         * CHANNEL_STATE_ERROR when conn is closed.
 +         */
 +        connection_or_close_for_error(conn, 0);
 +        return;
 +      }
 +      break;
 +    case OR_CONN_STATE_TLS_HANDSHAKING:
 +      /* If we're using bufferevents, it's entirely possible for us to
 +       * notice "hey, data arrived!" before we notice "hey, the handshake
 +       * finished!" And we need to be accepting both at once to handle both
 +       * the v2 and v3 handshakes. */
 +      /* But that should be happening any longer've disabled bufferevents. */
 +      tor_assert_nonfatal_unreached_once();
 +
 +      /* fall through */
 +    case OR_CONN_STATE_TLS_SERVER_RENEGOTIATING:
 +      if (!(command_allowed_before_handshake(var_cell->command))) {
 +        log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
 +               "Received a cell with command %d in unexpected "
 +               "orconn state "%s" [%d], channel state "%s" [%d]; "
 +               "closing the connection.",
 +               (int)(var_cell->command),
 +               conn_state_to_string(CONN_TYPE_OR, TO_CONN(conn)->state),
 +               (int)(TO_CONN(conn)->state),
 +               channel_state_to_string(TLS_CHAN_TO_BASE(chan)->state),
 +               (int)(TLS_CHAN_TO_BASE(chan)->state));
 +        /* see above comment about CHANNEL_STATE_ERROR */
 +        connection_or_close_for_error(conn, 0);
 +        return;
 +      } else {
 +        if (enter_v3_handshake_with_cell(var_cell, chan) < 0)
 +          return;
 +      }
 +      break;
 +    case OR_CONN_STATE_OR_HANDSHAKING_V3:
 +      if (var_cell->command != CELL_AUTHENTICATE)
 +        or_handshake_state_record_var_cell(conn, conn->handshake_state,
 +                                           var_cell, 1);
 +      break; /* Everything is allowed */
 +    case OR_CONN_STATE_OPEN:
 +      if (conn->link_proto < 3) {
 +        log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
 +               "Received a variable-length cell with command %d in orconn "
 +               "state %s [%d], channel state %s [%d] with link protocol %d; "
 +               "ignoring it.",
 +               (int)(var_cell->command),
 +               conn_state_to_string(CONN_TYPE_OR, TO_CONN(conn)->state),
 +               (int)(TO_CONN(conn)->state),
 +               channel_state_to_string(TLS_CHAN_TO_BASE(chan)->state),
 +               (int)(TLS_CHAN_TO_BASE(chan)->state),
 +               (int)(conn->link_proto));
 +        return;
 +      }
 +      break;
 +    default:
 +      log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
 +             "Received var-length cell with command %d in unexpected "
 +             "orconn state "%s" [%d], channel state "%s" [%d]; "
 +             "ignoring it.",
 +             (int)(var_cell->command),
 +             conn_state_to_string(CONN_TYPE_OR, TO_CONN(conn)->state),
 +             (int)(TO_CONN(conn)->state),
 +             channel_state_to_string(TLS_CHAN_TO_BASE(chan)->state),
 +             (int)(TLS_CHAN_TO_BASE(chan)->state));
 +      return;
 +  }
 +
 +  /* We note that we're on the internet whenever we read a cell. This is
 +   * a fast operation. */
 +  entry_guards_note_internet_connectivity(get_guard_selection_info());
 +
 +  /* Now handle the cell */
 +
 +  switch (var_cell->command) {
 +    case CELL_VERSIONS:
 +      ++stats_n_versions_cells_processed;
 +      PROCESS_CELL(versions, var_cell, chan);
 +      break;
 +    case CELL_VPADDING:
 +      ++stats_n_vpadding_cells_processed;
 +      /* Do nothing */
 +      break;
 +    case CELL_CERTS:
 +      ++stats_n_certs_cells_processed;
 +      PROCESS_CELL(certs, var_cell, chan);
 +      break;
 +    case CELL_AUTH_CHALLENGE:
 +      ++stats_n_auth_challenge_cells_processed;
 +      PROCESS_CELL(auth_challenge, var_cell, chan);
 +      break;
 +    case CELL_AUTHENTICATE:
 +      ++stats_n_authenticate_cells_processed;
 +      PROCESS_CELL(authenticate, var_cell, chan);
 +      break;
 +    case CELL_AUTHORIZE:
 +      ++stats_n_authorize_cells_processed;
 +      /* Ignored so far. */
 +      break;
 +    default:
 +      log_fn(LOG_INFO, LD_PROTOCOL,
 +             "Variable-length cell of unknown type (%d) received.",
 +             (int)(var_cell->command));
 +      break;
 +  }
 +}
 +
 +/**
 + * Update channel marks after connection_or.c has changed an address.
 + *
 + * This is called from connection_or_init_conn_from_address() after the
 + * connection's _base.addr or real_addr fields have potentially been changed
 + * so we can recalculate the local mark.  Notably, this happens when incoming
 + * connections are reverse-proxied and we only learn the real address of the
 + * remote router by looking it up in the consensus after we finish the
 + * handshake and know an authenticated identity digest.
 + */
 +void
 +channel_tls_update_marks(or_connection_t *conn)
 +{
 +  channel_t *chan = NULL;
 +
 +  tor_assert(conn);
 +  tor_assert(conn->chan);
 +
 +  chan = TLS_CHAN_TO_BASE(conn->chan);
 +
 +  if (is_local_addr(&(TO_CONN(conn)->addr))) {
 +    if (!channel_is_local(chan)) {
 +      log_debug(LD_CHANNEL,
 +                "Marking channel %"PRIu64 " at %p as local",
 +                (chan->global_identifier), chan);
 +      channel_mark_local(chan);
 +    }
 +  } else {
 +    if (channel_is_local(chan)) {
 +      log_debug(LD_CHANNEL,
 +                "Marking channel %"PRIu64 " at %p as remote",
 +                (chan->global_identifier), chan);
 +      channel_mark_remote(chan);
 +    }
 +  }
 +}
 +
 +/**
 + * Check if this cell type is allowed before the handshake is finished.
 + *
 + * Return true if <b>command</b> is a cell command that's allowed to start a
 + * V3 handshake.
 + */
 +static int
 +command_allowed_before_handshake(uint8_t command)
 +{
 +  switch (command) {
 +    case CELL_VERSIONS:
 +    case CELL_VPADDING:
 +    case CELL_AUTHORIZE:
 +      return 1;
 +    default:
 +      return 0;
 +  }
 +}
 +
 +/**
 + * Start a V3 handshake on an incoming connection.
 + *
 + * Called when we as a server receive an appropriate cell while waiting
 + * either for a cell or a TLS handshake.  Set the connection's state to
 + * "handshaking_v3', initializes the or_handshake_state field as needed,
 + * and add the cell to the hash of incoming cells.)
 + */
 +static int
 +enter_v3_handshake_with_cell(var_cell_t *cell, channel_tls_t *chan)
 +{
 +  int started_here = 0;
 +
 +  tor_assert(cell);
 +  tor_assert(chan);
 +  tor_assert(chan->conn);
 +
 +  started_here = connection_or_nonopen_was_started_here(chan->conn);
 +
 +  tor_assert(TO_CONN(chan->conn)->state == OR_CONN_STATE_TLS_HANDSHAKING ||
 +             TO_CONN(chan->conn)->state ==
 +               OR_CONN_STATE_TLS_SERVER_RENEGOTIATING);
 +
 +  if (started_here) {
 +    log_fn(LOG_PROTOCOL_WARN, LD_OR,
 +           "Received a cell while TLS-handshaking, not in "
 +           "OR_HANDSHAKING_V3, on a connection we originated.");
 +  }
 +  connection_or_block_renegotiation(chan->conn);
 +  chan->conn->base_.state = OR_CONN_STATE_OR_HANDSHAKING_V3;
 +  if (connection_init_or_handshake_state(chan->conn, started_here) < 0) {
 +    connection_or_close_for_error(chan->conn, 0);
 +    return -1;
 +  }
 +  or_handshake_state_record_var_cell(chan->conn,
 +                                     chan->conn->handshake_state, cell, 1);
 +  return 0;
 +}
 +
 +/**
 + * Process a 'versions' cell.
 + *
 + * This function is called to handle an incoming VERSIONS cell; the current
 + * link protocol version must be 0 to indicate that no version has yet been
 + * negotiated.  We compare the versions in the cell to the list of versions
 + * we support, pick the highest version we have in common, and continue the
 + * negotiation from there.
 + */
 +static void
 +channel_tls_process_versions_cell(var_cell_t *cell, channel_tls_t *chan)
 +{
 +  int highest_supported_version = 0;
 +  int started_here = 0;
 +
 +  tor_assert(cell);
 +  tor_assert(chan);
 +  tor_assert(chan->conn);
 +
 +  if ((cell->payload_len % 2) == 1) {
 +    log_fn(LOG_PROTOCOL_WARN, LD_OR,
 +           "Received a VERSION cell with odd payload length %d; "
 +           "closing connection.",cell->payload_len);
 +    connection_or_close_for_error(chan->conn, 0);
 +    return;
 +  }
 +
 +  started_here = connection_or_nonopen_was_started_here(chan->conn);
 +
 +  if (chan->conn->link_proto != 0 ||
 +      (chan->conn->handshake_state &&
 +       chan->conn->handshake_state->received_versions)) {
 +    log_fn(LOG_PROTOCOL_WARN, LD_OR,
 +           "Received a VERSIONS cell on a connection with its version "
 +           "already set to %d; dropping",
 +           (int)(chan->conn->link_proto));
 +    return;
 +  }
 +  switch (chan->conn->base_.state)
 +    {
 +    case OR_CONN_STATE_OR_HANDSHAKING_V2:
 +    case OR_CONN_STATE_OR_HANDSHAKING_V3:
 +      break;
 +    case OR_CONN_STATE_TLS_HANDSHAKING:
 +    case OR_CONN_STATE_TLS_SERVER_RENEGOTIATING:
 +    default:
 +      log_fn(LOG_PROTOCOL_WARN, LD_OR,
 +             "VERSIONS cell while in unexpected state");
 +      return;
 +  }
 +
 +  tor_assert(chan->conn->handshake_state);
 +
 +  {
 +    int i;
 +    const uint8_t *cp = cell->payload;
 +    for (i = 0; i < cell->payload_len / 2; ++i, cp += 2) {
 +      uint16_t v = ntohs(get_uint16(cp));
 +      if (is_or_protocol_version_known(v) && v > highest_supported_version)
 +        highest_supported_version = v;
 +    }
 +  }
 +  if (!highest_supported_version) {
 +    log_fn(LOG_PROTOCOL_WARN, LD_OR,
 +           "Couldn't find a version in common between my version list and the "
 +           "list in the VERSIONS cell; closing connection.");
 +    connection_or_close_for_error(chan->conn, 0);
 +    return;
 +  } else if (highest_supported_version == 1) {
 +    /* Negotiating version 1 makes no sense, since version 1 has no VERSIONS
 +     * cells. */
 +    log_fn(LOG_PROTOCOL_WARN, LD_OR,
 +           "Used version negotiation protocol to negotiate a v1 connection. "
 +           "That's crazily non-compliant. Closing connection.");
 +    connection_or_close_for_error(chan->conn, 0);
 +    return;
 +  } else if (highest_supported_version < 3 &&
 +             chan->conn->base_.state == OR_CONN_STATE_OR_HANDSHAKING_V3) {
 +    log_fn(LOG_PROTOCOL_WARN, LD_OR,
 +           "Negotiated link protocol 2 or lower after doing a v3 TLS "
 +           "handshake. Closing connection.");
 +    connection_or_close_for_error(chan->conn, 0);
 +    return;
 +  } else if (highest_supported_version != 2 &&
 +             chan->conn->base_.state == OR_CONN_STATE_OR_HANDSHAKING_V2) {
 +    /* XXXX This should eventually be a log_protocol_warn */
 +    log_fn(LOG_WARN, LD_OR,
 +           "Negotiated link with non-2 protocol after doing a v2 TLS "
 +           "handshake with %s. Closing connection.",
 +           fmt_addr(&chan->conn->base_.addr));
 +    connection_or_close_for_error(chan->conn, 0);
 +    return;
 +  }
 +
 +  rep_hist_note_negotiated_link_proto(highest_supported_version, started_here);
 +
 +  chan->conn->link_proto = highest_supported_version;
 +  chan->conn->handshake_state->received_versions = 1;
 +
 +  if (chan->conn->link_proto == 2) {
 +    log_info(LD_OR,
 +             "Negotiated version %d with %s:%d; sending NETINFO.",
 +             highest_supported_version,
 +             safe_str_client(chan->conn->base_.address),
 +             chan->conn->base_.port);
 +
 +    if (connection_or_send_netinfo(chan->conn) < 0) {
 +      connection_or_close_for_error(chan->conn, 0);
 +      return;
 +    }
 +  } else {
 +    const int send_versions = !started_here;
 +    /* If we want to authenticate, send a CERTS cell */
 +    const int send_certs = !started_here || public_server_mode(get_options());
 +    /* If we're a host that got a connection, ask for authentication. */
 +    const int send_chall = !started_here;
 +    /* If our certs cell will authenticate us, we can send a netinfo cell
 +     * right now. */
 +    const int send_netinfo = !started_here;
 +    const int send_any =
 +      send_versions || send_certs || send_chall || send_netinfo;
 +    tor_assert(chan->conn->link_proto >= 3);
 +
 +    log_info(LD_OR,
 +             "Negotiated version %d with %s:%d; %s%s%s%s%s",
 +             highest_supported_version,
 +             safe_str_client(chan->conn->base_.address),
 +             chan->conn->base_.port,
 +             send_any ? "Sending cells:" : "Waiting for CERTS cell",
 +             send_versions ? " VERSIONS" : "",
 +             send_certs ? " CERTS" : "",
 +             send_chall ? " AUTH_CHALLENGE" : "",
 +             send_netinfo ? " NETINFO" : "");
 +
 +#ifdef DISABLE_V3_LINKPROTO_SERVERSIDE
 +    if (1) {
 +      connection_or_close_normally(chan->conn, 1);
 +      return;
 +    }
 +#endif /* defined(DISABLE_V3_LINKPROTO_SERVERSIDE) */
 +
 +    if (send_versions) {
 +      if (connection_or_send_versions(chan->conn, 1) < 0) {
 +        log_warn(LD_OR, "Couldn't send versions cell");
 +        connection_or_close_for_error(chan->conn, 0);
 +        return;
 +      }
 +    }
 +
 +    /* We set this after sending the versions cell. */
 +    /*XXXXX symbolic const.*/
 +    TLS_CHAN_TO_BASE(chan)->wide_circ_ids =
 +      chan->conn->link_proto >= MIN_LINK_PROTO_FOR_WIDE_CIRC_IDS;
 +    chan->conn->wide_circ_ids = TLS_CHAN_TO_BASE(chan)->wide_circ_ids;
 +
 +    TLS_CHAN_TO_BASE(chan)->padding_enabled =
 +      chan->conn->link_proto >= MIN_LINK_PROTO_FOR_CHANNEL_PADDING;
 +
 +    if (send_certs) {
 +      if (connection_or_send_certs_cell(chan->conn) < 0) {
 +        log_warn(LD_OR, "Couldn't send certs cell");
 +        connection_or_close_for_error(chan->conn, 0);
 +        return;
 +      }
 +    }
 +    if (send_chall) {
 +      if (connection_or_send_auth_challenge_cell(chan->conn) < 0) {
 +        log_warn(LD_OR, "Couldn't send auth_challenge cell");
 +        connection_or_close_for_error(chan->conn, 0);
 +        return;
 +      }
 +    }
 +    if (send_netinfo) {
 +      if (connection_or_send_netinfo(chan->conn) < 0) {
 +        log_warn(LD_OR, "Couldn't send netinfo cell");
 +        connection_or_close_for_error(chan->conn, 0);
 +        return;
 +      }
 +    }
 +  }
 +}
 +
 +/**
 + * Process a 'padding_negotiate' cell.
 + *
 + * This function is called to handle an incoming PADDING_NEGOTIATE cell;
 + * enable or disable padding accordingly, and read and act on its timeout
 + * value contents.
 + */
 +static void
 +channel_tls_process_padding_negotiate_cell(cell_t *cell, channel_tls_t *chan)
 +{
 +  channelpadding_negotiate_t *negotiation;
 +  tor_assert(cell);
 +  tor_assert(chan);
 +  tor_assert(chan->conn);
 +
 +  if (chan->conn->link_proto < MIN_LINK_PROTO_FOR_CHANNEL_PADDING) {
 +    log_fn(LOG_PROTOCOL_WARN, LD_OR,
 +           "Received a PADDING_NEGOTIATE cell on v%d connection; dropping.",
 +           chan->conn->link_proto);
 +    return;
 +  }
 +
 +  if (channelpadding_negotiate_parse(&negotiation, cell->payload,
 +                                     CELL_PAYLOAD_SIZE) < 0) {
 +    log_fn(LOG_PROTOCOL_WARN, LD_OR,
 +          "Received malformed PADDING_NEGOTIATE cell on v%d connection; "
 +          "dropping.", chan->conn->link_proto);
 +
 +    return;
 +  }
 +
 +  channelpadding_update_padding_for_channel(TLS_CHAN_TO_BASE(chan),
 +                                            negotiation);
 +
 +  channelpadding_negotiate_free(negotiation);
 +}
 +
 +/**
 + * Helper: compute the absolute value of a time_t.
 + *
 + * (we need this because labs() doesn't always work for time_t, since
 + * long can be shorter than time_t.)
 + */
 +static inline time_t
 +time_abs(time_t val)
 +{
 +  return (val < 0) ? -val : val;
 +}
 +
 +/**
 + * Process a 'netinfo' cell
 + *
 + * This function is called to handle an incoming NETINFO cell; read and act
 + * on its contents, and set the connection state to "open".
 + */
 +static void
 +channel_tls_process_netinfo_cell(cell_t *cell, channel_tls_t *chan)
 +{
 +  time_t timestamp;
 +  uint8_t my_addr_type;
 +  uint8_t my_addr_len;
 +  const uint8_t *my_addr_ptr;
 +  const uint8_t *cp, *end;
 +  uint8_t n_other_addrs;
 +  time_t now = time(NULL);
 +  const routerinfo_t *me = router_get_my_routerinfo();
 +
 +  time_t apparent_skew = 0;
 +  tor_addr_t my_apparent_addr = TOR_ADDR_NULL;
 +  int started_here = 0;
 +  const char *identity_digest = NULL;
 +
 +  tor_assert(cell);
 +  tor_assert(chan);
 +  tor_assert(chan->conn);
 +
 +  if (chan->conn->link_proto < 2) {
 +    log_fn(LOG_PROTOCOL_WARN, LD_OR,
 +           "Received a NETINFO cell on %s connection; dropping.",
 +           chan->conn->link_proto == 0 ? "non-versioned" : "a v1");
 +    return;
 +  }
 +  if (chan->conn->base_.state != OR_CONN_STATE_OR_HANDSHAKING_V2 &&
 +      chan->conn->base_.state != OR_CONN_STATE_OR_HANDSHAKING_V3) {
 +    log_fn(LOG_PROTOCOL_WARN, LD_OR,
 +           "Received a NETINFO cell on non-handshaking connection; dropping.");
 +    return;
 +  }
 +  tor_assert(chan->conn->handshake_state &&
 +             chan->conn->handshake_state->received_versions);
 +  started_here = connection_or_nonopen_was_started_here(chan->conn);
 +  identity_digest = chan->conn->identity_digest;
 +
 +  if (chan->conn->base_.state == OR_CONN_STATE_OR_HANDSHAKING_V3) {
 +    tor_assert(chan->conn->link_proto >= 3);
 +    if (started_here) {
 +      if (!(chan->conn->handshake_state->authenticated)) {
 +        log_fn(LOG_PROTOCOL_WARN, LD_OR,
 +               "Got a NETINFO cell from server, "
 +               "but no authentication.  Closing the connection.");
 +        connection_or_close_for_error(chan->conn, 0);
 +        return;
 +      }
 +    } else {
 +      /* we're the server.  If the client never authenticated, we have
 +         some housekeeping to do.*/
 +      if (!(chan->conn->handshake_state->authenticated)) {
 +        tor_assert(tor_digest_is_zero(
 +                  (const char*)(chan->conn->handshake_state->
 +                      authenticated_rsa_peer_id)));
 +        tor_assert(tor_mem_is_zero(
 +                  (const char*)(chan->conn->handshake_state->
 +                                authenticated_ed25519_peer_id.pubkey), 32));
 +        /* If the client never authenticated, it's a tor client or bridge
 +         * relay, and we must not use it for EXTEND requests (nor could we, as
 +         * there are no authenticated peer IDs) */
 +        channel_mark_client(TLS_CHAN_TO_BASE(chan));
 +        channel_set_circid_type(TLS_CHAN_TO_BASE(chan), NULL,
 +               chan->conn->link_proto < MIN_LINK_PROTO_FOR_WIDE_CIRC_IDS);
 +
 +        connection_or_init_conn_from_address(chan->conn,
 +                  &(chan->conn->base_.addr),
 +                  chan->conn->base_.port,
 +                  /* zero, checked above */
 +                  (const char*)(chan->conn->handshake_state->
 +                                authenticated_rsa_peer_id),
 +                  NULL, /* Ed25519 ID: Also checked as zero */
 +                  0);
 +      }
 +    }
 +  }
 +
 +  /* Decode the cell. */
 +  timestamp = ntohl(get_uint32(cell->payload));
 +  const time_t sent_versions_at =
 +    chan->conn->handshake_state->sent_versions_at;
 +  if (now > sent_versions_at && (now - sent_versions_at) < 180) {
 +    /* If we have gotten the NETINFO cell reasonably soon after having
 +     * sent our VERSIONS cell, maybe we can learn skew information from it. */
 +    apparent_skew = now - timestamp;
 +  }
 +
 +  my_addr_type = (uint8_t) cell->payload[4];
 +  my_addr_len = (uint8_t) cell->payload[5];
 +  my_addr_ptr = (uint8_t*) cell->payload + 6;
 +  end = cell->payload + CELL_PAYLOAD_SIZE;
 +  cp = cell->payload + 6 + my_addr_len;
 +
 +  /* We used to check:
 +   *    if (my_addr_len >= CELL_PAYLOAD_SIZE - 6) {
 +   *
 +   * This is actually never going to happen, since my_addr_len is at most 255,
 +   * and CELL_PAYLOAD_LEN - 6 is 503.  So we know that cp is < end. */
 +
 +  if (my_addr_type == RESOLVED_TYPE_IPV4 && my_addr_len == 4) {
 +    tor_addr_from_ipv4n(&my_apparent_addr, get_uint32(my_addr_ptr));
 +
 +    if (!get_options()->BridgeRelay && me &&
 +        get_uint32(my_addr_ptr) == htonl(me->addr)) {
 +      TLS_CHAN_TO_BASE(chan)->is_canonical_to_peer = 1;
 +    }
 +
 +  } else if (my_addr_type == RESOLVED_TYPE_IPV6 && my_addr_len == 16) {
 +    tor_addr_from_ipv6_bytes(&my_apparent_addr, (const char *) my_addr_ptr);
 +
 +    if (!get_options()->BridgeRelay && me &&
 +        !tor_addr_is_null(&me->ipv6_addr) &&
 +        tor_addr_eq(&my_apparent_addr, &me->ipv6_addr)) {
 +      TLS_CHAN_TO_BASE(chan)->is_canonical_to_peer = 1;
 +    }
 +  }
 +
 +  n_other_addrs = (uint8_t) *cp++;
 +  while (n_other_addrs && cp < end-2) {
 +    /* Consider all the other addresses; if any matches, this connection is
 +     * "canonical." */
 +    tor_addr_t addr;
 +    const uint8_t *next =
 +      decode_address_from_payload(&addr, cp, (int)(end-cp));
 +    if (next == NULL) {
 +      log_fn(LOG_PROTOCOL_WARN,  LD_OR,
 +             "Bad address in netinfo cell; closing connection.");
 +      connection_or_close_for_error(chan->conn, 0);
 +      return;
 +    }
 +    /* A relay can connect from anywhere and be canonical, so
 +     * long as it tells you from where it came. This may sound a bit
 +     * concerning... but that's what "canonical" means: that the
 +     * address is one that the relay itself has claimed.  The relay
 +     * might be doing something funny, but nobody else is doing a MITM
 +     * on the relay's TCP.
 +     */
 +    if (tor_addr_eq(&addr, &(chan->conn->real_addr))) {
 +      connection_or_set_canonical(chan->conn, 1);
 +      break;
 +    }
 +    cp = next;
 +    --n_other_addrs;
 +  }
 +
 +  if (me && !TLS_CHAN_TO_BASE(chan)->is_canonical_to_peer &&
 +      channel_is_canonical(TLS_CHAN_TO_BASE(chan))) {
 +    const char *descr =
 +      TLS_CHAN_TO_BASE(chan)->get_remote_descr(TLS_CHAN_TO_BASE(chan), 0);
 +    log_info(LD_OR,
 +             "We made a connection to a relay at %s (fp=%s) but we think "
 +             "they will not consider this connection canonical. They "
 +             "think we are at %s, but we think its %s.",
 +             safe_str(descr),
 +             safe_str(hex_str(identity_digest, DIGEST_LEN)),
 +             safe_str(tor_addr_is_null(&my_apparent_addr) ?
 +             "<none>" : fmt_and_decorate_addr(&my_apparent_addr)),
 +             safe_str(fmt_addr32(me->addr)));
 +  }
 +
 +  /* Act on apparent skew. */
 +  /** Warn when we get a netinfo skew with at least this value. */
 +#define NETINFO_NOTICE_SKEW 3600
 +  if (time_abs(apparent_skew) > NETINFO_NOTICE_SKEW &&
 +      (started_here ||
 +       connection_or_digest_is_known_relay(chan->conn->identity_digest))) {
 +    int trusted = router_digest_is_trusted_dir(chan->conn->identity_digest);
 +    clock_skew_warning(TO_CONN(chan->conn), apparent_skew, trusted, LD_GENERAL,
 +                       "NETINFO cell", "OR");
 +  }
 +
 +  /* XXX maybe act on my_apparent_addr, if the source is sufficiently
 +   * trustworthy. */
 +
 +  if (! chan->conn->handshake_state->sent_netinfo) {
 +    /* If we were prepared to authenticate, but we never got an AUTH_CHALLENGE
 +     * cell, then we would not previously have sent a NETINFO cell. Do so
 +     * now. */
 +    if (connection_or_send_netinfo(chan->conn) < 0) {
 +      connection_or_close_for_error(chan->conn, 0);
 +      return;
 +    }
 +  }
 +
 +  if (connection_or_set_state_open(chan->conn) < 0) {
 +    log_fn(LOG_PROTOCOL_WARN, LD_OR,
 +           "Got good NETINFO cell from %s:%d; but "
 +           "was unable to make the OR connection become open.",
 +           safe_str_client(chan->conn->base_.address),
 +           chan->conn->base_.port);
 +    connection_or_close_for_error(chan->conn, 0);
 +  } else {
 +    log_info(LD_OR,
 +             "Got good NETINFO cell from %s:%d; OR connection is now "
 +             "open, using protocol version %d. Its ID digest is %s. "
 +             "Our address is apparently %s.",
 +             safe_str_client(chan->conn->base_.address),
 +             chan->conn->base_.port,
 +             (int)(chan->conn->link_proto),
 +             hex_str(identity_digest, DIGEST_LEN),
 +             tor_addr_is_null(&my_apparent_addr) ?
 +               "<none>" :
 +               safe_str_client(fmt_and_decorate_addr(&my_apparent_addr)));
 +  }
 +  assert_connection_ok(TO_CONN(chan->conn),time(NULL));
 +}
 +
 +/** Types of certificates that we know how to parse from CERTS cells.  Each
 + * type corresponds to a different encoding format. */
 +typedef enum cert_encoding_t {
 +  CERT_ENCODING_UNKNOWN, /**< We don't recognize this. */
 +  CERT_ENCODING_X509, /**< It's an RSA key, signed with RSA, encoded in x509.
 +                   * (Actually, it might not be RSA. We test that later.) */
 +  CERT_ENCODING_ED25519, /**< It's something signed with an Ed25519 key,
 +                      * encoded asa a tor_cert_t.*/
 +  CERT_ENCODING_RSA_CROSSCERT, /**< It's an Ed key signed with an RSA key. */
 +} cert_encoding_t;
 +
 +/**
 + * Given one of the certificate type codes used in a CERTS cell,
 + * return the corresponding cert_encoding_t that we should use to parse
 + * the certificate.
 + */
 +static cert_encoding_t
 +certs_cell_typenum_to_cert_type(int typenum)
 +{
 +  switch (typenum) {
 +  case CERTTYPE_RSA1024_ID_LINK:
 +  case CERTTYPE_RSA1024_ID_ID:
 +  case CERTTYPE_RSA1024_ID_AUTH:
 +    return CERT_ENCODING_X509;
 +  case CERTTYPE_ED_ID_SIGN:
 +  case CERTTYPE_ED_SIGN_LINK:
 +  case CERTTYPE_ED_SIGN_AUTH:
 +    return CERT_ENCODING_ED25519;
 +  case CERTTYPE_RSA1024_ID_EDID:
 +    return CERT_ENCODING_RSA_CROSSCERT;
 +  default:
 +    return CERT_ENCODING_UNKNOWN;
 +  }
 +}
 +
 +/**
 + * Process a CERTS cell from a channel.
 + *
 + * This function is called to process an incoming CERTS cell on a
 + * channel_tls_t:
 + *
 + * If the other side should not have sent us a CERTS cell, or the cell is
 + * malformed, or it is supposed to authenticate the TLS key but it doesn't,
 + * then mark the connection.
 + *
 + * If the cell has a good cert chain and we're doing a v3 handshake, then
 + * store the certificates in or_handshake_state.  If this is the client side
 + * of the connection, we then authenticate the server or mark the connection.
 + * If it's the server side, wait for an AUTHENTICATE cell.
 + */
 +STATIC void
 +channel_tls_process_certs_cell(var_cell_t *cell, channel_tls_t *chan)
 +{
 +#define MAX_CERT_TYPE_WANTED CERTTYPE_RSA1024_ID_EDID
 +  /* These arrays will be sparse, since a cert type can be at most one
 +   * of ed/x509 */
 +  tor_x509_cert_t *x509_certs[MAX_CERT_TYPE_WANTED + 1];
 +  tor_cert_t *ed_certs[MAX_CERT_TYPE_WANTED + 1];
 +  uint8_t *rsa_ed_cc_cert = NULL;
 +  size_t rsa_ed_cc_cert_len = 0;
 +
 +  int n_certs, i;
 +  certs_cell_t *cc = NULL;
 +
 +  int send_netinfo = 0, started_here = 0;
 +
 +  memset(x509_certs, 0, sizeof(x509_certs));
 +  memset(ed_certs, 0, sizeof(ed_certs));
 +  tor_assert(cell);
 +  tor_assert(chan);
 +  tor_assert(chan->conn);
 +
 +#define ERR(s)                                                  \
 +  do {                                                          \
 +    log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,                      \
 +           "Received a bad CERTS cell from %s:%d: %s",          \
 +           safe_str(chan->conn->base_.address),                 \
 +           chan->conn->base_.port, (s));                        \
 +    connection_or_close_for_error(chan->conn, 0);               \
 +    goto err;                                                   \
 +  } while (0)
 +
 +  /* Can't use connection_or_nonopen_was_started_here(); its conn->tls
 +   * check looks like it breaks
 +   * test_link_handshake_recv_certs_ok_server().  */
 +  started_here = chan->conn->handshake_state->started_here;
 +
 +  if (chan->conn->base_.state != OR_CONN_STATE_OR_HANDSHAKING_V3)
 +    ERR("We're not doing a v3 handshake!");
 +  if (chan->conn->link_proto < 3)
 +    ERR("We're not using link protocol >= 3");
 +  if (chan->conn->handshake_state->received_certs_cell)
 +    ERR("We already got one");
 +  if (chan->conn->handshake_state->authenticated) {
 +    /* Should be unreachable, but let's make sure. */
 +    ERR("We're already authenticated!");
 +  }
 +  if (cell->payload_len < 1)
 +    ERR("It had no body");
 +  if (cell->circ_id)
 +    ERR("It had a nonzero circuit ID");
 +
 +  if (certs_cell_parse(&cc, cell->payload, cell->payload_len) < 0)
 +    ERR("It couldn't be parsed.");
 +
 +  n_certs = cc->n_certs;
 +
 +  for (i = 0; i < n_certs; ++i) {
 +    certs_cell_cert_t *c = certs_cell_get_certs(cc, i);
 +
 +    uint16_t cert_type = c->cert_type;
 +    uint16_t cert_len = c->cert_len;
 +    uint8_t *cert_body = certs_cell_cert_getarray_body(c);
 +
 +    if (cert_type > MAX_CERT_TYPE_WANTED)
 +      continue;
 +    const cert_encoding_t ct = certs_cell_typenum_to_cert_type(cert_type);
 +    switch (ct) {
 +      default:
 +      case CERT_ENCODING_UNKNOWN:
 +        break;
 +      case CERT_ENCODING_X509: {
 +        tor_x509_cert_t *x509_cert = tor_x509_cert_decode(cert_body, cert_len);
 +        if (!x509_cert) {
 +          log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
 +                 "Received undecodable certificate in CERTS cell from %s:%d",
 +                 safe_str(chan->conn->base_.address),
 +               chan->conn->base_.port);
 +        } else {
 +          if (x509_certs[cert_type]) {
 +            tor_x509_cert_free(x509_cert);
 +            ERR("Duplicate x509 certificate");
 +          } else {
 +            x509_certs[cert_type] = x509_cert;
 +          }
 +        }
 +        break;
 +      }
 +      case CERT_ENCODING_ED25519: {
 +        tor_cert_t *ed_cert = tor_cert_parse(cert_body, cert_len);
 +        if (!ed_cert) {
 +          log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
 +                 "Received undecodable Ed certificate "
 +                 "in CERTS cell from %s:%d",
 +                 safe_str(chan->conn->base_.address),
 +               chan->conn->base_.port);
 +        } else {
 +          if (ed_certs[cert_type]) {
 +            tor_cert_free(ed_cert);
 +            ERR("Duplicate Ed25519 certificate");
 +          } else {
 +            ed_certs[cert_type] = ed_cert;
 +          }
 +        }
 +        break;
 +      }
 +
 +     case CERT_ENCODING_RSA_CROSSCERT: {
 +        if (rsa_ed_cc_cert) {
 +          ERR("Duplicate RSA->Ed25519 crosscert");
 +        } else {
 +          rsa_ed_cc_cert = tor_memdup(cert_body, cert_len);
 +          rsa_ed_cc_cert_len = cert_len;
 +        }
 +        break;
 +      }
 +    }
 +  }
 +
 +  /* Move the certificates we (might) want into the handshake_state->certs
 +   * structure. */
 +  tor_x509_cert_t *id_cert = x509_certs[CERTTYPE_RSA1024_ID_ID];
 +  tor_x509_cert_t *auth_cert = x509_certs[CERTTYPE_RSA1024_ID_AUTH];
 +  tor_x509_cert_t *link_cert = x509_certs[CERTTYPE_RSA1024_ID_LINK];
 +  chan->conn->handshake_state->certs->auth_cert = auth_cert;
 +  chan->conn->handshake_state->certs->link_cert = link_cert;
 +  chan->conn->handshake_state->certs->id_cert = id_cert;
 +  x509_certs[CERTTYPE_RSA1024_ID_ID] =
 +    x509_certs[CERTTYPE_RSA1024_ID_AUTH] =
 +    x509_certs[CERTTYPE_RSA1024_ID_LINK] = NULL;
 +
 +  tor_cert_t *ed_id_sign = ed_certs[CERTTYPE_ED_ID_SIGN];
 +  tor_cert_t *ed_sign_link = ed_certs[CERTTYPE_ED_SIGN_LINK];
 +  tor_cert_t *ed_sign_auth = ed_certs[CERTTYPE_ED_SIGN_AUTH];
 +  chan->conn->handshake_state->certs->ed_id_sign = ed_id_sign;
 +  chan->conn->handshake_state->certs->ed_sign_link = ed_sign_link;
 +  chan->conn->handshake_state->certs->ed_sign_auth = ed_sign_auth;
 +  ed_certs[CERTTYPE_ED_ID_SIGN] =
 +    ed_certs[CERTTYPE_ED_SIGN_LINK] =
 +    ed_certs[CERTTYPE_ED_SIGN_AUTH] = NULL;
 +
 +  chan->conn->handshake_state->certs->ed_rsa_crosscert = rsa_ed_cc_cert;
 +  chan->conn->handshake_state->certs->ed_rsa_crosscert_len =
 +    rsa_ed_cc_cert_len;
 +  rsa_ed_cc_cert = NULL;
 +
 +  int severity;
 +  /* Note that this warns more loudly about time and validity if we were
 +   * _trying_ to connect to an authority, not necessarily if we _did_ connect
 +   * to one. */
 +  if (started_here &&
 +      router_digest_is_trusted_dir(TLS_CHAN_TO_BASE(chan)->identity_digest))
 +    severity = LOG_WARN;
 +  else
 +    severity = LOG_PROTOCOL_WARN;
 +
 +  const ed25519_public_key_t *checked_ed_id = NULL;
 +  const common_digests_t *checked_rsa_id = NULL;
 +  or_handshake_certs_check_both(severity,
 +                                chan->conn->handshake_state->certs,
 +                                chan->conn->tls,
 +                                time(NULL),
 +                                &checked_ed_id,
 +                                &checked_rsa_id);
 +
 +  if (!checked_rsa_id)
 +    ERR("Invalid certificate chain!");
 +
 +  if (started_here) {
 +    /* No more information is needed. */
 +
 +    chan->conn->handshake_state->authenticated = 1;
 +    chan->conn->handshake_state->authenticated_rsa = 1;
 +    {
 +      const common_digests_t *id_digests = checked_rsa_id;
 +      crypto_pk_t *identity_rcvd;
 +      if (!id_digests)
 +        ERR("Couldn't compute digests for key in ID cert");
 +
 +      identity_rcvd = tor_tls_cert_get_key(id_cert);
 +      if (!identity_rcvd) {
 +        ERR("Couldn't get RSA key from ID cert.");
 +      }
 +      memcpy(chan->conn->handshake_state->authenticated_rsa_peer_id,
 +             id_digests->d[DIGEST_SHA1], DIGEST_LEN);
 +      channel_set_circid_type(TLS_CHAN_TO_BASE(chan), identity_rcvd,
 +                chan->conn->link_proto < MIN_LINK_PROTO_FOR_WIDE_CIRC_IDS);
 +      crypto_pk_free(identity_rcvd);
 +    }
 +
 +    if (checked_ed_id) {
 +      chan->conn->handshake_state->authenticated_ed25519 = 1;
 +      memcpy(&chan->conn->handshake_state->authenticated_ed25519_peer_id,
 +             checked_ed_id, sizeof(ed25519_public_key_t));
 +    }
 +
 +    log_debug(LD_HANDSHAKE, "calling client_learned_peer_id from "
 +              "process_certs_cell");
 +
 +    if (connection_or_client_learned_peer_id(chan->conn,
 +                  chan->conn->handshake_state->authenticated_rsa_peer_id,
 +                  checked_ed_id) < 0)
 +      ERR("Problem setting or checking peer id");
 +
 +    log_info(LD_HANDSHAKE,
 +             "Got some good certificates from %s:%d: Authenticated it with "
 +             "RSA%s",
 +             safe_str(chan->conn->base_.address), chan->conn->base_.port,
 +             checked_ed_id ? " and Ed25519" : "");
 +
 +    if (!public_server_mode(get_options())) {
 +      /* If we initiated the connection and we are not a public server, we
 +       * aren't planning to authenticate at all.  At this point we know who we
 +       * are talking to, so we can just send a netinfo now. */
 +      send_netinfo = 1;
 +    }
 +  } else {
 +    /* We can't call it authenticated till we see an AUTHENTICATE cell. */
 +    log_info(LD_OR,
 +             "Got some good RSA%s certificates from %s:%d. "
 +             "Waiting for AUTHENTICATE.",
 +             checked_ed_id ? " and Ed25519" : "",
 +             safe_str(chan->conn->base_.address),
 +             chan->conn->base_.port);
 +    /* XXXX check more stuff? */
 +  }
 +
 +  chan->conn->handshake_state->received_certs_cell = 1;
 +
 +  if (send_netinfo) {
 +    if (connection_or_send_netinfo(chan->conn) < 0) {
 +      log_warn(LD_OR, "Couldn't send netinfo cell");
 +      connection_or_close_for_error(chan->conn, 0);
 +      goto err;
 +    }
 +  }
 +
 + err:
 +  for (unsigned u = 0; u < ARRAY_LENGTH(x509_certs); ++u) {
 +    tor_x509_cert_free(x509_certs[u]);
 +  }
 +  for (unsigned u = 0; u < ARRAY_LENGTH(ed_certs); ++u) {
 +    tor_cert_free(ed_certs[u]);
 +  }
 +  tor_free(rsa_ed_cc_cert);
 +  certs_cell_free(cc);
 +#undef ERR
 +}
 +
 +/**
 + * Process an AUTH_CHALLENGE cell from a channel_tls_t.
 + *
 + * This function is called to handle an incoming AUTH_CHALLENGE cell on a
 + * channel_tls_t; if we weren't supposed to get one (for example, because we're
 + * not the originator of the channel), or it's ill-formed, or we aren't doing
 + * a v3 handshake, mark the channel.  If the cell is well-formed but we don't
 + * want to authenticate, just drop it.  If the cell is well-formed *and* we
 + * want to authenticate, send an AUTHENTICATE cell and then a NETINFO cell.
 + */
 +STATIC void
 +channel_tls_process_auth_challenge_cell(var_cell_t *cell, channel_tls_t *chan)
 +{
 +  int n_types, i, use_type = -1;
 +  auth_challenge_cell_t *ac = NULL;
 +
 +  tor_assert(cell);
 +  tor_assert(chan);
 +  tor_assert(chan->conn);
 +
 +#define ERR(s)                                                  \
 +  do {                                                          \
 +    log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,                      \
 +           "Received a bad AUTH_CHALLENGE cell from %s:%d: %s", \
 +           safe_str(chan->conn->base_.address),                 \
 +           chan->conn->base_.port, (s));                        \
 +    connection_or_close_for_error(chan->conn, 0);               \
 +    goto done;                                                  \
 +  } while (0)
 +
 +  if (chan->conn->base_.state != OR_CONN_STATE_OR_HANDSHAKING_V3)
 +    ERR("We're not currently doing a v3 handshake");
 +  if (chan->conn->link_proto < 3)
 +    ERR("We're not using link protocol >= 3");
 +  if (!(chan->conn->handshake_state->started_here))
 +    ERR("We didn't originate this connection");
 +  if (chan->conn->handshake_state->received_auth_challenge)
 +    ERR("We already received one");
 +  if (!(chan->conn->handshake_state->received_certs_cell))
 +    ERR("We haven't gotten a CERTS cell yet");
 +  if (cell->circ_id)
 +    ERR("It had a nonzero circuit ID");
 +
 +  if (auth_challenge_cell_parse(&ac, cell->payload, cell->payload_len) < 0)
 +    ERR("It was not well-formed.");
 +
 +  n_types = ac->n_methods;
 +
 +  /* Now see if there is an authentication type we can use */
 +  for (i = 0; i < n_types; ++i) {
 +    uint16_t authtype = auth_challenge_cell_get_methods(ac, i);
 +    if (authchallenge_type_is_supported(authtype)) {
 +      if (use_type == -1 ||
 +          authchallenge_type_is_better(authtype, use_type)) {
 +        use_type = authtype;
 +      }
 +    }
 +  }
 +
 +  chan->conn->handshake_state->received_auth_challenge = 1;
 +
 +  if (! public_server_mode(get_options())) {
 +    /* If we're not a public server then we don't want to authenticate on a
 +       connection we originated, and we already sent a NETINFO cell when we
 +       got the CERTS cell. We have nothing more to do. */
 +    goto done;
 +  }
 +
 +  if (use_type >= 0) {
 +    log_info(LD_OR,
 +             "Got an AUTH_CHALLENGE cell from %s:%d: Sending "
 +             "authentication type %d",
 +             safe_str(chan->conn->base_.address),
 +             chan->conn->base_.port,
 +             use_type);
 +
 +    if (connection_or_send_authenticate_cell(chan->conn, use_type) < 0) {
 +      log_warn(LD_OR,
 +               "Couldn't send authenticate cell");
 +      connection_or_close_for_error(chan->conn, 0);
 +      goto done;
 +    }
 +  } else {
 +    log_info(LD_OR,
 +             "Got an AUTH_CHALLENGE cell from %s:%d, but we don't "
 +             "know any of its authentication types. Not authenticating.",
 +             safe_str(chan->conn->base_.address),
 +             chan->conn->base_.port);
 +  }
 +
 +  if (connection_or_send_netinfo(chan->conn) < 0) {
 +    log_warn(LD_OR, "Couldn't send netinfo cell");
 +    connection_or_close_for_error(chan->conn, 0);
 +    goto done;
 +  }
 +
 + done:
 +  auth_challenge_cell_free(ac);
 +
 +#undef ERR
 +}
 +
 +/**
 + * Process an AUTHENTICATE cell from a channel_tls_t.
 + *
 + * If it's ill-formed or we weren't supposed to get one or we're not doing a
 + * v3 handshake, then mark the connection.  If it does not authenticate the
 + * other side of the connection successfully (because it isn't signed right,
 + * we didn't get a CERTS cell, etc) mark the connection.  Otherwise, accept
 + * the identity of the router on the other side of the connection.
 + */
 +STATIC void
 +channel_tls_process_authenticate_cell(var_cell_t *cell, channel_tls_t *chan)
 +{
 +  var_cell_t *expected_cell = NULL;
 +  const uint8_t *auth;
 +  int authlen;
 +  int authtype;
 +  int bodylen;
 +
 +  tor_assert(cell);
 +  tor_assert(chan);
 +  tor_assert(chan->conn);
 +
 +#define ERR(s)                                                  \
 +  do {                                                          \
 +    log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,                      \
 +           "Received a bad AUTHENTICATE cell from %s:%d: %s",   \
 +           safe_str(chan->conn->base_.address),                 \
 +           chan->conn->base_.port, (s));                        \
 +    connection_or_close_for_error(chan->conn, 0);               \
 +    var_cell_free(expected_cell);                               \
 +    return;                                                     \
 +  } while (0)
 +
 +  if (chan->conn->base_.state != OR_CONN_STATE_OR_HANDSHAKING_V3)
 +    ERR("We're not doing a v3 handshake");
 +  if (chan->conn->link_proto < 3)
 +    ERR("We're not using link protocol >= 3");
 +  if (chan->conn->handshake_state->started_here)
 +    ERR("We originated this connection");
 +  if (chan->conn->handshake_state->received_authenticate)
 +    ERR("We already got one!");
 +  if (chan->conn->handshake_state->authenticated) {
 +    /* Should be impossible given other checks */
 +    ERR("The peer is already authenticated");
 +  }
 +  if (!(chan->conn->handshake_state->received_certs_cell))
 +    ERR("We never got a certs cell");
 +  if (chan->conn->handshake_state->certs->id_cert == NULL)
 +    ERR("We never got an identity certificate");
 +  if (cell->payload_len < 4)
 +    ERR("Cell was way too short");
 +
 +  auth = cell->payload;
 +  {
 +    uint16_t type = ntohs(get_uint16(auth));
 +    uint16_t len = ntohs(get_uint16(auth+2));
 +    if (4 + len > cell->payload_len)
 +      ERR("Authenticator was truncated");
 +
 +    if (! authchallenge_type_is_supported(type))
 +      ERR("Authenticator type was not recognized");
 +    authtype = type;
 +
 +    auth += 4;
 +    authlen = len;
 +  }
 +
 +  if (authlen < V3_AUTH_BODY_LEN + 1)
 +    ERR("Authenticator was too short");
 +
 +  expected_cell = connection_or_compute_authenticate_cell_body(
 +                chan->conn, authtype, NULL, NULL, 1);
 +  if (! expected_cell)
 +    ERR("Couldn't compute expected AUTHENTICATE cell body");
 +
 +  int sig_is_rsa;
 +  if (authtype == AUTHTYPE_RSA_SHA256_TLSSECRET ||
 +      authtype == AUTHTYPE_RSA_SHA256_RFC5705) {
 +    bodylen = V3_AUTH_BODY_LEN;
 +    sig_is_rsa = 1;
 +  } else {
 +    tor_assert(authtype == AUTHTYPE_ED25519_SHA256_RFC5705);
 +    /* Our earlier check had better have made sure we had room
 +     * for an ed25519 sig (inadvertently) */
 +    tor_assert(V3_AUTH_BODY_LEN > ED25519_SIG_LEN);
 +    bodylen = authlen - ED25519_SIG_LEN;
 +    sig_is_rsa = 0;
 +  }
 +  if (expected_cell->payload_len != bodylen+4) {
 +    ERR("Expected AUTHENTICATE cell body len not as expected.");
 +  }
 +
 +  /* Length of random part. */
 +  if (BUG(bodylen < 24)) {
 +    // LCOV_EXCL_START
 +    ERR("Bodylen is somehow less than 24, which should really be impossible");
 +    // LCOV_EXCL_STOP
 +  }
 +
 +  if (tor_memneq(expected_cell->payload+4, auth, bodylen-24))
 +    ERR("Some field in the AUTHENTICATE cell body was not as expected");
 +
 +  if (sig_is_rsa) {
 +    if (chan->conn->handshake_state->certs->ed_id_sign != NULL)
 +      ERR("RSA-signed AUTHENTICATE response provided with an ED25519 cert");
 +
 +    if (chan->conn->handshake_state->certs->auth_cert == NULL)
 +      ERR("We never got an RSA authentication certificate");
 +
 +    crypto_pk_t *pk = tor_tls_cert_get_key(
 +                             chan->conn->handshake_state->certs->auth_cert);
 +    char d[DIGEST256_LEN];
 +    char *signed_data;
 +    size_t keysize;
 +    int signed_len;
 +
 +    if (! pk) {
 +      ERR("Couldn't get RSA key from AUTH cert.");
 +    }
 +    crypto_digest256(d, (char*)auth, V3_AUTH_BODY_LEN, DIGEST_SHA256);
 +
 +    keysize = crypto_pk_keysize(pk);
 +    signed_data = tor_malloc(keysize);
 +    signed_len = crypto_pk_public_checksig(pk, signed_data, keysize,
 +                                           (char*)auth + V3_AUTH_BODY_LEN,
 +                                           authlen - V3_AUTH_BODY_LEN);
 +    crypto_pk_free(pk);
 +    if (signed_len < 0) {
 +      tor_free(signed_data);
 +      ERR("RSA signature wasn't valid");
 +    }
 +    if (signed_len < DIGEST256_LEN) {
 +      tor_free(signed_data);
 +      ERR("Not enough data was signed");
 +    }
 +    /* Note that we deliberately allow *more* than DIGEST256_LEN bytes here,
 +     * in case they're later used to hold a SHA3 digest or something. */
 +    if (tor_memneq(signed_data, d, DIGEST256_LEN)) {
 +      tor_free(signed_data);
 +      ERR("Signature did not match data to be signed.");
 +    }
 +    tor_free(signed_data);
 +  } else {
 +    if (chan->conn->handshake_state->certs->ed_id_sign == NULL)
 +      ERR("We never got an Ed25519 identity certificate.");
 +    if (chan->conn->handshake_state->certs->ed_sign_auth == NULL)
 +      ERR("We never got an Ed25519 authentication certificate.");
 +
 +    const ed25519_public_key_t *authkey =
 +      &chan->conn->handshake_state->certs->ed_sign_auth->signed_key;
 +    ed25519_signature_t sig;
 +    tor_assert(authlen > ED25519_SIG_LEN);
 +    memcpy(&sig.sig, auth + authlen - ED25519_SIG_LEN, ED25519_SIG_LEN);
 +    if (ed25519_checksig(&sig, auth, authlen - ED25519_SIG_LEN, authkey)<0) {
 +      ERR("Ed25519 signature wasn't valid.");
 +    }
 +  }
 +
 +  /* Okay, we are authenticated. */
 +  chan->conn->handshake_state->received_authenticate = 1;
 +  chan->conn->handshake_state->authenticated = 1;
 +  chan->conn->handshake_state->authenticated_rsa = 1;
 +  chan->conn->handshake_state->digest_received_data = 0;
 +  {
 +    tor_x509_cert_t *id_cert = chan->conn->handshake_state->certs->id_cert;
 +    crypto_pk_t *identity_rcvd = tor_tls_cert_get_key(id_cert);
 +    const common_digests_t *id_digests = tor_x509_cert_get_id_digests(id_cert);
 +    const ed25519_public_key_t *ed_identity_received = NULL;
 +
 +    if (! sig_is_rsa) {
 +      chan->conn->handshake_state->authenticated_ed25519 = 1;
 +      ed_identity_received =
 +        &chan->conn->handshake_state->certs->ed_id_sign->signing_key;
 +      memcpy(&chan->conn->handshake_state->authenticated_ed25519_peer_id,
 +             ed_identity_received, sizeof(ed25519_public_key_t));
 +    }
 +
 +    /* This must exist; we checked key type when reading the cert. */
 +    tor_assert(id_digests);
 +
 +    memcpy(chan->conn->handshake_state->authenticated_rsa_peer_id,
 +           id_digests->d[DIGEST_SHA1], DIGEST_LEN);
 +
 +    channel_set_circid_type(TLS_CHAN_TO_BASE(chan), identity_rcvd,
 +               chan->conn->link_proto < MIN_LINK_PROTO_FOR_WIDE_CIRC_IDS);
 +    crypto_pk_free(identity_rcvd);
 +
 +    log_debug(LD_HANDSHAKE,
 +              "Calling connection_or_init_conn_from_address for %s "
 +              " from %s, with%s ed25519 id.",
 +              safe_str(chan->conn->base_.address),
 +              __func__,
 +              ed_identity_received ? "" : "out");
 +
 +    connection_or_init_conn_from_address(chan->conn,
 +                  &(chan->conn->base_.addr),
 +                  chan->conn->base_.port,
 +                  (const char*)(chan->conn->handshake_state->
 +                    authenticated_rsa_peer_id),
 +                  ed_identity_received,
 +                  0);
 +
 +    log_debug(LD_HANDSHAKE,
 +             "Got an AUTHENTICATE cell from %s:%d, type %d: Looks good.",
 +             safe_str(chan->conn->base_.address),
 +             chan->conn->base_.port,
 +             authtype);
 +  }
 +
 +  var_cell_free(expected_cell);
 +
 +#undef ERR
 +}

    