tor

btrack_orconn_maps.c (5607B)

---

/* Copyright (c) 2007-2021, The Tor Project, Inc. */
/* See LICENSE for licensing information */

/**
* \file btrack_orconn_maps.c
* \brief Hash map implementation for btrack_orconn.c
*
* These functions manipulate the hash maps that contain bt_orconn
* objects.
**/

#include <stdbool.h>

#include "core/or/or.h"

#include "ht.h"
#include "siphash.h"

#define BTRACK_ORCONN_PRIVATE

#include "feature/control/btrack_orconn.h"
#include "feature/control/btrack_orconn_maps.h"
#include "lib/log/log.h"

static inline unsigned int
bto_gid_hash_(bt_orconn_t *elm)
{
 return (unsigned)siphash24g(&elm->gid, sizeof(elm->gid));
}

static inline int
bto_gid_eq_(bt_orconn_t *a, bt_orconn_t *b)
{
 return a->gid == b->gid;
}

static inline unsigned int
bto_chan_hash_(bt_orconn_t *elm)
{
 return (unsigned)siphash24g(&elm->chan, sizeof(elm->chan));
}

static inline int
bto_chan_eq_(bt_orconn_t *a, bt_orconn_t *b)
{
 return a->chan == b->chan;
}

HT_HEAD(bto_gid_ht, bt_orconn_t);
HT_PROTOTYPE(bto_gid_ht, bt_orconn_t, node, bto_gid_hash_, bto_gid_eq_);
HT_GENERATE2(bto_gid_ht, bt_orconn_t, node,
            bto_gid_hash_, bto_gid_eq_, 0.6,
            tor_reallocarray_, tor_free_);
static struct bto_gid_ht *bto_gid_map;

HT_HEAD(bto_chan_ht, bt_orconn_t);
HT_PROTOTYPE(bto_chan_ht, bt_orconn_t, chan_node, bto_chan_hash_,
            bto_chan_eq_);
HT_GENERATE2(bto_chan_ht, bt_orconn_t, chan_node,
            bto_chan_hash_, bto_chan_eq_, 0.6,
            tor_reallocarray_, tor_free_);
static struct bto_chan_ht *bto_chan_map;

/** Clear the GID hash map, freeing any bt_orconn_t objects that become
* unreferenced */
static void
bto_gid_clear_map(void)
{
 bt_orconn_t **elt, **next, *c;

 for (elt = HT_START(bto_gid_ht, bto_gid_map);
      elt;
      elt = next) {
   c = *elt;
   next = HT_NEXT_RMV(bto_gid_ht, bto_gid_map, elt);

   c->gid = 0;
   /* Don't delete if chan ID isn't zero: it's still in the chan hash map */
   if (!c->chan)
     tor_free(c);
 }
 HT_CLEAR(bto_gid_ht, bto_gid_map);
 tor_free(bto_gid_map);
}

/** Clear the chan ID hash map, freeing any bt_orconn_t objects that
* become unreferenced */
static void
bto_chan_clear_map(void)
{
 bt_orconn_t **elt, **next, *c;

 for (elt = HT_START(bto_chan_ht, bto_chan_map);
      elt;
      elt = next) {
   c = *elt;
   next = HT_NEXT_RMV(bto_chan_ht, bto_chan_map, elt);

   c->chan = 0;
   /* Don't delete if GID isn't zero, it's still in the GID hash map */
   if (!c->gid)
     tor_free(c);
 }
 HT_CLEAR(bto_chan_ht, bto_chan_map);
 tor_free(bto_chan_map);
}

/** Delete a bt_orconn from the hash maps by GID */
void
bto_delete(uint64_t gid)
{
 bt_orconn_t key, *bto;

 key.gid = gid;
 key.chan = 0;
 bto = HT_FIND(bto_gid_ht, bto_gid_map, &key);
 if (!bto) {
   /* The orconn might be unregistered because it's an EXT_OR_CONN? */
   log_debug(LD_BTRACK, "tried to delete unregistered ORCONN gid=%"PRIu64,
             gid);
   return;
 }
 HT_REMOVE(bto_gid_ht, bto_gid_map, &key);
 if (bto->chan) {
   key.chan = bto->chan;
   HT_REMOVE(bto_chan_ht, bto_chan_map, &key);
 }
 tor_free(bto);
}

/**
* Helper for bto_find_or_new().
*
* Update GID and chan ID of an existing bt_orconn object if needed,
* given a search key previously used within bto_find_or_new().
**/
static bt_orconn_t *
bto_update(bt_orconn_t *bto, const bt_orconn_t *key)
{
 /* ORCONN GIDs shouldn't change once assigned */
 tor_assert(!bto->gid || !key->gid || bto->gid == key->gid);
 if (!bto->gid && key->gid) {
   /* Got a gid when we didn't already have one; insert into gid map */
   log_debug(LD_BTRACK, "ORCONN chan=%"PRIu64" newgid=%"PRIu64, key->chan,
             key->gid);
   bto->gid = key->gid;
   HT_INSERT(bto_gid_ht, bto_gid_map, bto);
 }
 /* association of ORCONN with channel shouldn't change */
 tor_assert(!bto->chan || !key->chan || bto->chan == key->chan);
 if (!bto->chan && key->chan) {
   /* Got a chan when we didn't already have one; insert into chan map */
   log_debug(LD_BTRACK, "ORCONN gid=%"PRIu64" newchan=%"PRIu64,
             bto->gid, key->chan);
   bto->chan = key->chan;
   HT_INSERT(bto_chan_ht, bto_chan_map, bto);
 }
 return bto;
}

/** Helper for bto_find_or_new() */
static bt_orconn_t *
bto_new(const bt_orconn_t *key)
{
 struct bt_orconn_t *bto = tor_malloc(sizeof(*bto));

 bto->gid = key->gid;
 bto->chan = key->chan;
 bto->state = 0;
 bto->proxy_type = 0;
 bto->is_orig = false;
 bto->is_onehop = true;

 if (bto->gid)
   HT_INSERT(bto_gid_ht, bto_gid_map, bto);
 if (bto->chan)
   HT_INSERT(bto_chan_ht, bto_chan_map, bto);

 return bto;
}

/**
* Insert a new bt_orconn with the given GID and chan ID, or update
* the GID and chan ID if one already exists.
*
* Return the found or allocated bt_orconn.
**/
bt_orconn_t *
bto_find_or_new(uint64_t gid, uint64_t chan)
{
 bt_orconn_t key, *bto = NULL;

 tor_assert(gid || chan);
 key.gid = gid;
 key.chan = chan;
 if (key.gid)
   bto = HT_FIND(bto_gid_ht, bto_gid_map, &key);
 if (!bto && key.chan) {
   /* Not found by GID; look up by chan ID */
   bto = HT_FIND(bto_chan_ht, bto_chan_map, &key);
 }
 if (bto)
   return bto_update(bto, &key);
 else
   return bto_new(&key);
}

/** Initialize the hash maps  */
void
bto_init_maps(void)
{
 bto_gid_map = tor_malloc(sizeof(*bto_gid_map));
 HT_INIT(bto_gid_ht, bto_gid_map);
 bto_chan_map = tor_malloc(sizeof(*bto_chan_map));
 HT_INIT(bto_chan_ht, bto_chan_map);
}

/** Clear the hash maps, freeing all associated storage */
void
bto_clear_maps(void)
{
 bto_gid_clear_map();
 bto_chan_clear_map();
}