commit e46c3d95f4257fd1292c721a5d737af0f74f2f83 Author: teor teor@riseup.net Date: Wed May 13 13:23:39 2020 +1000

circuitbuild: Do node checks when counting nodes

Use the node check function to check that there are enough nodes to select a circuit path.

Adds these checks, which are implied by other code: * supports EXTEND2 cells, * does not allow single-hop exits,

Adds these extra checks: * has a general-purpose routerinfo, * if it is a direct connection, check reachable addresses. These checks reduce the node count, but they will never under-count nodes.

Bridge nodes aren't handled correctly, we'll fix that in the next commit.

Part of 34200. --- src/core/or/circuitbuild.c | 29 ++++++++++++----------------- 1 file changed, 12 insertions(+), 17 deletions(-)

diff --git a/src/core/or/circuitbuild.c b/src/core/or/circuitbuild.c index bac82eb9f..233ea9bd0 100644 --- a/src/core/or/circuitbuild.c +++ b/src/core/or/circuitbuild.c @@ -2103,32 +2103,27 @@ circuit_extend_to_new_exit(origin_circuit_t *circ, extend_info_t *exit_ei) return 0; }

-/** Return the number of routers in <b>routers</b> that are currently up - * and available for building circuits through. +/** Return the number of routers in <b>nodes</b> that are currently up and + * available for building circuits through. * - * (Note that this function may overcount or undercount, if we have - * descriptors that are not the type we would prefer to use for some - * particular router. See bug #25885.) + * If <b>direct</b> is true, only count nodes that are suitable for direct + * connections. Counts nodes regardless of whether their addresses are + * preferred. */ MOCK_IMPL(STATIC int, count_acceptable_nodes, (const smartlist_t *nodes, int direct)) { int num=0; + int flags = CRN_NEED_DESC; + + if (direct) + flags |= CRN_DIRECT_CONN;

SMARTLIST_FOREACH_BEGIN(nodes, const node_t *, node) { // log_debug(LD_CIRC, -// "Contemplating whether router %d (%s) is a new option.", -// i, r->nickname); - if (! node->is_running) -// log_debug(LD_CIRC,"Nope, the directory says %d is not running.",i); - continue; - if (! node->is_valid) -// log_debug(LD_CIRC,"Nope, the directory says %d is not valid.",i); - continue; - if (! node_has_preferred_descriptor(node, direct)) - continue; - /* The node has a descriptor, so we can just check the ntor key directly */ - if (!node_has_curve25519_onion_key(node)) + // "Contemplating whether router %d (%s) is a new option.", + // i, r->nickname); + if (!router_can_choose_node(node, flags)) continue; ++num; } SMARTLIST_FOREACH_END(node);