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[tor-commits] [tor/release-0.4.5] node: Move reentry set to use a digestmap_t
commit bd4a3f64a1f6802c97a7976ff9f80495ef3ba57d
Author: David Goulet <dgoulet@xxxxxxxxxxxxxx>
Date: Mon Feb 1 12:20:39 2021 -0500
node: Move reentry set to use a digestmap_t
Any lookup now will be certain and not probabilistic as the bloomfilter.
Closes #40269
Signed-off-by: David Goulet <dgoulet@xxxxxxxxxxxxxx>
---
src/core/or/connection_edge.c | 2 +-
src/feature/nodelist/nodelist.c | 63 ++++++++++++++++++++++++++++++++---------
src/feature/nodelist/nodelist.h | 3 +-
src/test/test_address_set.c | 12 ++++----
4 files changed, 57 insertions(+), 23 deletions(-)
diff --git a/src/core/or/connection_edge.c b/src/core/or/connection_edge.c
index da5431c47e..27a616fa24 100644
--- a/src/core/or/connection_edge.c
+++ b/src/core/or/connection_edge.c
@@ -4290,7 +4290,7 @@ connection_exit_connect(edge_connection_t *edge_conn)
* case of an attack so this is a small price to pay. */
if (!connection_edge_is_rendezvous_stream(edge_conn) &&
!network_reentry_is_allowed() &&
- nodelist_reentry_probably_contains(&conn->addr, conn->port)) {
+ nodelist_reentry_contains(&conn->addr, conn->port)) {
log_info(LD_EXIT, "%s tried to connect back to a known relay address. "
"Closing.", connection_describe(conn));
connection_edge_end(edge_conn, END_STREAM_REASON_TORPROTOCOL);
diff --git a/src/feature/nodelist/nodelist.c b/src/feature/nodelist/nodelist.c
index 6a6f277849..03b158e68d 100644
--- a/src/feature/nodelist/nodelist.c
+++ b/src/feature/nodelist/nodelist.c
@@ -137,7 +137,7 @@ typedef struct nodelist_t {
/* Set of addresses + port that belong to nodes we know and that we don't
* allow network re-entry towards them. */
- addr_port_set_t *reentry_set;
+ digestmap_t *reentry_set;
/* The valid-after time of the last live consensus that initialized the
* nodelist. We use this to detect outdated nodelists that need to be
@@ -485,6 +485,42 @@ node_add_to_address_set(const node_t *node)
}
}
+/** Build a construction for the reentry set consisting of an address and port
+ * pair.
+ *
+ * If the given address is _not_ AF_INET or AF_INET6, then the item is an
+ * array of 0s.
+ *
+ * Return a pointer to a static buffer containing the item. Next call to this
+ * function invalidates its previous content. */
+static char *
+build_addr_port_item(const tor_addr_t *addr, const uint16_t port)
+{
+ /* At most 16 bytes are put in this (IPv6) and then 2 bytes for the port
+ * which is within the maximum of 20 bytes (DIGEST_LEN). */
+ static char data[DIGEST_LEN];
+
+ memset(data, 0, sizeof(data));
+ switch (tor_addr_family(addr)) {
+ case AF_INET:
+ memcpy(data, &addr->addr.in_addr.s_addr, 4);
+ break;
+ case AF_INET6:
+ memcpy(data, &addr->addr.in6_addr.s6_addr, 16);
+ break;
+ case AF_UNSPEC:
+ /* Leave the 0. */
+ break;
+ default:
+ /* LCOV_EXCL_START */
+ tor_fragile_assert();
+ /* LCOV_EXCL_STOP */
+ }
+
+ memcpy(data + 16, &port, sizeof(port));
+ return data;
+}
+
/** Add the given address into the nodelist address set. */
void
nodelist_add_addr_to_address_set(const tor_addr_t *addr,
@@ -498,10 +534,12 @@ nodelist_add_addr_to_address_set(const tor_addr_t *addr,
}
address_set_add(the_nodelist->node_addrs, addr);
if (or_port != 0) {
- addr_port_set_add(the_nodelist->reentry_set, addr, or_port);
+ digestmap_set(the_nodelist->reentry_set,
+ build_addr_port_item(addr, or_port), (void*) 1);
}
if (dir_port != 0) {
- addr_port_set_add(the_nodelist->reentry_set, addr, dir_port);
+ digestmap_set(the_nodelist->reentry_set,
+ build_addr_port_item(addr, dir_port), (void*) 1);
}
}
@@ -522,7 +560,7 @@ nodelist_probably_contains_address(const tor_addr_t *addr)
/** Return true if <b>addr</b> is the address of some node in the nodelist and
* corresponds also to the given port. If not, probably return false. */
bool
-nodelist_reentry_probably_contains(const tor_addr_t *addr, uint16_t port)
+nodelist_reentry_contains(const tor_addr_t *addr, uint16_t port)
{
if (BUG(!addr) || BUG(!port))
return false;
@@ -530,8 +568,8 @@ nodelist_reentry_probably_contains(const tor_addr_t *addr, uint16_t port)
if (!the_nodelist || !the_nodelist->reentry_set)
return false;
- return addr_port_set_probably_contains(the_nodelist->reentry_set,
- addr, port);
+ return digestmap_get(the_nodelist->reentry_set,
+ build_addr_port_item(addr, port)) != NULL;
}
/** Add <b>ri</b> to an appropriate node in the nodelist. If we replace an
@@ -667,15 +705,12 @@ nodelist_set_consensus(const networkstatus_t *ns)
get_estimated_address_per_node();
estimated_addresses += (get_n_authorities(V3_DIRINFO | BRIDGE_DIRINFO) *
get_estimated_address_per_node());
+ /* Clear our sets because we will repopulate them with what this new
+ * consensus contains. */
address_set_free(the_nodelist->node_addrs);
- addr_port_set_free(the_nodelist->reentry_set);
the_nodelist->node_addrs = address_set_new(estimated_addresses);
- /* Times two here is for both the ORPort and DirPort. We double it again in
- * order to minimize as much as possible the false positive when looking up
- * this set. Reason is that Exit streams that are legitimate but end up a
- * false positive against this set will thus be considered reentry and be
- * rejected which means a bad UX. */
- the_nodelist->reentry_set = addr_port_set_new(estimated_addresses * 2 * 2);
+ digestmap_free(the_nodelist->reentry_set, NULL);
+ the_nodelist->reentry_set = digestmap_new();
SMARTLIST_FOREACH_BEGIN(ns->routerstatus_list, routerstatus_t *, rs) {
node_t *node = node_get_or_create(rs->identity_digest);
@@ -902,7 +937,7 @@ nodelist_free_all(void)
address_set_free(the_nodelist->node_addrs);
the_nodelist->node_addrs = NULL;
- addr_port_set_free(the_nodelist->reentry_set);
+ digestmap_free(the_nodelist->reentry_set, NULL);
the_nodelist->reentry_set = NULL;
tor_free(the_nodelist);
diff --git a/src/feature/nodelist/nodelist.h b/src/feature/nodelist/nodelist.h
index ada0a640a1..44b8918b06 100644
--- a/src/feature/nodelist/nodelist.h
+++ b/src/feature/nodelist/nodelist.h
@@ -35,8 +35,7 @@ node_t *nodelist_add_microdesc(microdesc_t *md);
void nodelist_set_consensus(const networkstatus_t *ns);
void nodelist_ensure_freshness(const networkstatus_t *ns);
int nodelist_probably_contains_address(const tor_addr_t *addr);
-bool nodelist_reentry_probably_contains(const tor_addr_t *addr,
- uint16_t port);
+bool nodelist_reentry_contains(const tor_addr_t *addr, uint16_t port);
void nodelist_add_addr_to_address_set(const tor_addr_t *addr,
uint16_t or_port, uint16_t dir_port);
diff --git a/src/test/test_address_set.c b/src/test/test_address_set.c
index 55a0b106d2..a73fbab76a 100644
--- a/src/test/test_address_set.c
+++ b/src/test/test_address_set.c
@@ -215,8 +215,8 @@ test_exit_no_reentry(void *arg)
nodelist_set_consensus(dummy_ns);
/* The address set is empty. Try it anyway */
- tt_assert(!nodelist_reentry_probably_contains(&addr_v4, 244));
- tt_assert(!nodelist_reentry_probably_contains(&addr_v6, 244));
+ tt_assert(!nodelist_reentry_contains(&addr_v4, 244));
+ tt_assert(!nodelist_reentry_contains(&addr_v6, 244));
/* Now let's populate the network */
md = tor_malloc_zero(sizeof(*md));
@@ -243,12 +243,12 @@ test_exit_no_reentry(void *arg)
/* First let's try an address that is on the no-reentry list, but with a
different port */
- tt_assert(!nodelist_reentry_probably_contains(&addr_v4, 666));
- tt_assert(!nodelist_reentry_probably_contains(&addr_v6, 444));
+ tt_assert(!nodelist_reentry_contains(&addr_v4, 666));
+ tt_assert(!nodelist_reentry_contains(&addr_v6, 444));
/* OK now let's try with the right address and right port */
- tt_assert(nodelist_reentry_probably_contains(&addr_v4, 444));
- tt_assert(nodelist_reentry_probably_contains(&addr_v6, 666));
+ tt_assert(nodelist_reentry_contains(&addr_v4, 444));
+ tt_assert(nodelist_reentry_contains(&addr_v6, 666));
done:
routerstatus_free(rs); routerinfo_free(ri); microdesc_free(md);
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