1 files changed, 328 insertions, 0 deletions

diff --git a/src/or/nodelist.c b/src/or/nodelist.c
new file mode 100644
index 0000000000..9c8714c354
--- /dev/null
+++ b/src/or/nodelist.c
@@ -0,0 +1,328 @@
+/* Copyright (c) 2001 Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2010, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+#include "or.h"
+#include "nodelist.h"
+#include "microdesc.h"
+#include "networkstatus.h"
+#include "routerlist.h"
+
+#include <string.h>
+
+static void nodelist_drop_node(node_t *node);
+static void node_free(node_t *node);
+
+/** A nodelist_t holds a node_t object for every router we're "willing to use
+ * for something".  Specifically, it should hold a node_t for every node that
+ * is currently in the routerlist, or currently in the consensus we're using.
+ */
+typedef struct nodelist_t {
+  /* A list of all the nodes. */
+  smartlist_t *nodes;
+  /* Hash table to map from node ID digest to node. */
+  HT_HEAD(nodelist_map, node_t) nodes_by_id;
+} nodelist_t;
+
+static INLINE unsigned int
+node_id_hash(const node_t *node)
+{
+#if SIZEOF_INT == 4
+  const uint32_t *p = (const uint32_t*)node->identity;
+  return p[0] ^ p[1] ^ p[2] ^ p[3] ^ p[4];
+#elif SIZEOF_INT == 8
+  const uint64_t *p = (const uint32_t*)node->identity;
+  const uint32_t *p32 = (const uint32_t*)node->identity;
+  return p[0] ^ p[1] ^ p32[4];
+#endif
+}
+
+static INLINE unsigned int
+node_id_eq(const node_t *node1, const node_t *node2)
+{
+  return 0 == memcmp(node1->identity, node2->identity, DIGEST_LEN);
+}
+
+HT_PROTOTYPE(nodelist_map, node_t, ht_ent, node_id_hash, node_id_eq);
+HT_GENERATE(nodelist_map, node_t, ht_ent, node_id_hash, node_id_eq,
+            0.6, malloc, realloc, free);
+
+/** The global nodelist. */
+static nodelist_t *the_nodelist=NULL;
+
+/** Create an empty nodelist if we haven't done so already. */
+static void
+init_nodelist(void)
+{
+  if (PREDICT_UNLIKELY(the_nodelist == NULL)) {
+    the_nodelist = tor_malloc_zero(sizeof(nodelist_t));
+    HT_INIT(nodelist_map, &the_nodelist->nodes_by_id);
+    the_nodelist->nodes = smartlist_create();
+  }
+}
+
+/** Return the node_t whose identity is <b>identity_digest</b>, or NULL
+ * if no such node exists. */
+node_t *
+node_get_by_id(const char *identity_digest)
+{
+  node_t search, *node;
+  if (PREDICT_UNLIKELY(the_nodelist == NULL))
+    return NULL;
+
+  memcpy(&search.identity, identity_digest, DIGEST_LEN);
+  node = HT_FIND(nodelist_map, &the_nodelist->nodes_by_id, &search);
+  return node;
+}
+
+/** Internal: return the node_t whose identity_digest is
+ * <b>identity_digest</b>.  If none exists, create a new one, add it to the
+ * nodelist, and return it.
+ *
+ * Requires that the nodelist be initialized.
+ */
+static node_t *
+node_get_or_create(const char *identity_digest)
+{
+  node_t *node;
+
+  if ((node = node_get_by_id(identity_digest)))
+    return node;
+
+  node = tor_malloc_zero(sizeof(node_t));
+  memcpy(node->identity, identity_digest, DIGEST_LEN);
+  HT_INSERT(nodelist_map, &the_nodelist->nodes_by_id, node);
+
+  smartlist_add(the_nodelist->nodes, node);
+  node->nodelist_idx = smartlist_len(the_nodelist->nodes) - 1;
+
+  return node;
+}
+
+/** Add <b>ri</b> to the nodelist. */
+node_t *
+nodelist_add_routerinfo(routerinfo_t *ri)
+{
+  node_t *node;
+  init_nodelist();
+  node = node_get_or_create(ri->cache_info.identity_digest);
+  node->ri = ri;
+  return node;
+}
+
+/** Set the appropriate node_t to use <b>md</b> as its microdescriptor.
+ *
+ * Called when a new microdesc has arrived and the usable consensus flavor
+ * is "microdesc".
+ **/
+node_t *
+nodelist_add_microdesc(microdesc_t *md)
+{
+  networkstatus_t *ns =
+    networkstatus_get_latest_consensus_by_flavor(FLAV_MICRODESC);
+  routerstatus_t *rs;
+  node_t *node;
+  if (ns == NULL)
+    return NULL;
+  init_nodelist();
+
+  /* Microdescriptors don't carry an identity digest, so we need to figure
+   * it out by looking up the routerstatus. */
+  rs = router_get_consensus_status_by_descriptor_digest(ns, md->digest);
+  if (rs == NULL)
+    return NULL;
+  node = node_get_by_id(rs->identity_digest);
+  if (node)
+    node->md = md;
+  return node;
+}
+
+/** Tell the nodelist that the current usable consensus to <b>ns</b>.
+ * This makes the nodelist change all of the routerstatus entries for
+ * the nodes, drop nodes that no longer have enough info to get used,
+ * and grab microdescriptors into nodes as appropriate.
+ */
+void
+nodelist_set_consensus(networkstatus_t *ns)
+{
+  init_nodelist();
+
+  SMARTLIST_FOREACH(the_nodelist->nodes, node_t *, node,
+                    node->rs = NULL);
+
+  SMARTLIST_FOREACH_BEGIN(ns->routerstatus_list, routerstatus_t *, rs) {
+    node_t *node = node_get_or_create(rs->identity_digest);
+    node->rs = rs;
+    if (ns->flavor == FLAV_MICRODESC) {
+      if (node->md == NULL ||
+          0!=memcmp(node->md->digest,rs->descriptor_digest,DIGEST256_LEN)) {
+        node->md = microdesc_cache_lookup_by_digest256(NULL,
+                                                       rs->descriptor_digest);
+      }
+    }
+  } SMARTLIST_FOREACH_END(rs);
+  nodelist_purge();
+}
+
+/** Helper: return true iff a node has a usable amount of information*/
+static INLINE int
+node_is_usable(const node_t *node)
+{
+  return (node->rs) || (node->ri);
+}
+
+/** Tell the nodelist that <b>md</b> is no longer a microdescriptor for the
+ * node with <b>identity_digest</b>. */
+void
+nodelist_remove_microdesc(const char *identity_digest, microdesc_t *md)
+{
+  node_t *node = node_get_by_id(identity_digest);
+  if (node && node->md == md)
+    node->md = NULL;
+}
+
+/** Tell the nodelist that <b>ri</b> is no longer in the routerlist. */
+void
+nodelist_remove_routerinfo(routerinfo_t *ri)
+{
+  node_t *node = node_get_by_id(ri->cache_info.identity_digest);
+  if (node && node->ri == ri) {
+    node->ri = NULL;
+    if (! node_is_usable(node)) {
+      nodelist_drop_node(node);
+      node_free(node);
+    }
+  }
+}
+
+/** Remove <b>node</b> from the nodelist.  (Asserts that it was there to begin
+ * with.) */
+static void
+nodelist_drop_node(node_t *node)
+{
+  node_t *tmp;
+  int idx;
+  tmp = HT_REMOVE(nodelist_map, &the_nodelist->nodes_by_id, node);
+  tor_assert(tmp == node);
+
+  idx = node->nodelist_idx;
+  tor_assert(idx >= 0);
+
+  tor_assert(node == smartlist_get(the_nodelist->nodes, idx));
+  smartlist_del(the_nodelist->nodes, idx);
+  if (idx < smartlist_len(the_nodelist->nodes)) {
+    tmp = smartlist_get(the_nodelist->nodes, idx);
+    tmp->nodelist_idx = idx;
+  }
+  node->nodelist_idx = -1;
+}
+
+/** Release storage held by <b>node</b>  */
+static void
+node_free(node_t *node)
+{
+  if (!node)
+    return;
+  tor_assert(node->nodelist_idx == -1);
+  tor_free(node);
+}
+
+/** Remove all entries from the nodelist that don't have enough info to be
+ * usable for anything. */
+void
+nodelist_purge(void)
+{
+  node_t **iter;
+  if (PREDICT_UNLIKELY(the_nodelist == NULL))
+    return;
+
+  for (iter = HT_START(nodelist_map, &the_nodelist->nodes_by_id); iter; ) {
+    node_t *node = *iter;
+
+    if (node_is_usable(node)) {
+      iter = HT_NEXT(nodelist_map, &the_nodelist->nodes_by_id, iter);
+    } else {
+      iter = HT_NEXT_RMV(nodelist_map, &the_nodelist->nodes_by_id, iter);
+      nodelist_drop_node(node);
+      node_free(node);
+    }
+  }
+
+}
+
+/** Release all storage held by the nodelist. */
+void
+nodelist_free_all(void)
+{
+  if (PREDICT_UNLIKELY(the_nodelist == NULL))
+    return;
+
+  HT_CLEAR(nodelist_map, &the_nodelist->nodes_by_id);
+  SMARTLIST_FOREACH_BEGIN(the_nodelist->nodes, node_t *, node) {
+    node->nodelist_idx = -1;
+    node_free(node);
+  } SMARTLIST_FOREACH_END(node);
+
+  smartlist_free(the_nodelist->nodes);
+
+  tor_free(the_nodelist);
+}
+
+/** Check that the nodelist is internally consistent, and consistent with
+ * the directory info it's derived from.
+ */
+void
+nodelist_assert_ok(void)
+{
+  routerlist_t *rl = router_get_routerlist();
+  networkstatus_t *ns = networkstatus_get_latest_consensus();
+  digestmap_t *dm = digestmap_new();
+
+  if (!the_nodelist)
+    return;
+
+  /* every routerinfo in rl->routers should be in the nodelist. */
+  if (rl) {
+    SMARTLIST_FOREACH_BEGIN(rl->routers, routerinfo_t *, ri) {
+      node_t *node = node_get_by_id(ri->cache_info.identity_digest);
+      tor_assert(node && node->ri == ri);
+      tor_assert(0 == memcmp(ri->cache_info.identity_digest,
+                             node->identity, DIGEST_LEN));
+      tor_assert(! digestmap_get(dm, node->identity));
+      digestmap_set(dm, node->identity, node);
+    } SMARTLIST_FOREACH_END(ri);
+  }
+
+  /* every routerstatus in ns should be in the nodelist */
+  if (ns) {
+    SMARTLIST_FOREACH_BEGIN(ns->routerstatus_list, routerstatus_t *, rs) {
+      node_t *node = node_get_by_id(rs->identity_digest);
+      tor_assert(node && node->rs == rs);
+      tor_assert(0 == memcmp(rs->identity_digest, node->identity, DIGEST_LEN));
+      digestmap_set(dm, node->identity, node);
+      if (ns->flavor == FLAV_MICRODESC) {
+        /* If it's a microdesc consensus, every entry that has a microdescriptor
+         * should be in the nodelist.
+         */
+        microdesc_t *md =
+          microdesc_cache_lookup_by_digest256(NULL, rs->descriptor_digest);
+        tor_assert(md == node->md);
+      }
+    } SMARTLIST_FOREACH_END(rs);
+  }
+
+  /* The nodelist should have no other entries, and its entries should be
+   * well-formed. */
+  SMARTLIST_FOREACH_BEGIN(the_nodelist->nodes, node_t *, node) {
+    tor_assert(digestmap_get(dm, node->identity) != NULL);
+    tor_assert(node_sl_idx == node->nodelist_idx);
+  } SMARTLIST_FOREACH_END(node);
+
+  tor_assert((long)smartlist_len(the_nodelist->nodes) ==
+             (long)HT_SIZE(&the_nodelist->nodes_by_id));
+
+  digestmap_free(dm, NULL);
+}
+