commit 1c1faf586ab7083221e02da4315679c5cf13d151 Author: teor teor@riseup.net Date: Mon May 11 17:00:25 2020 +1000

routerlist: Choose nodes that can initiate IPv6 extends

Part of 33226. --- src/core/or/circuitbuild.c | 17 ++++++++----- src/feature/nodelist/node_select.c | 49 ++++++++++++++++++++++---------------- src/feature/nodelist/node_select.h | 2 ++ src/feature/nodelist/routerlist.c | 9 ++++--- src/feature/nodelist/routerlist.h | 3 ++- 5 files changed, 50 insertions(+), 30 deletions(-)

diff --git a/src/core/or/circuitbuild.c b/src/core/or/circuitbuild.c index ba70c4753..1cf9e588f 100644 --- a/src/core/or/circuitbuild.c +++ b/src/core/or/circuitbuild.c @@ -1796,12 +1796,13 @@ pick_restricted_middle_node(router_crn_flags_t flags,

/* Add all running nodes to all_live_nodes */ router_add_running_nodes_to_smartlist(all_live_nodes, - (flags & CRN_NEED_UPTIME) != 0, - (flags & CRN_NEED_CAPACITY) != 0, - (flags & CRN_NEED_GUARD) != 0, - (flags & CRN_NEED_DESC) != 0, - (flags & CRN_PREF_ADDR) != 0, - (flags & CRN_DIRECT_CONN) != 0); + (flags & CRN_NEED_UPTIME) != 0, + (flags & CRN_NEED_CAPACITY) != 0, + (flags & CRN_NEED_GUARD) != 0, + (flags & CRN_NEED_DESC) != 0, + (flags & CRN_PREF_ADDR) != 0, + (flags & CRN_DIRECT_CONN) != 0, + (flags & CRN_INITIATE_IPV6_EXTEND) != 0);

/* Filter all_live_nodes to only add live *and* whitelisted middles * to the list whitelisted_live_middles. */ @@ -2306,6 +2307,10 @@ choose_good_middle_server(uint8_t purpose, flags |= CRN_NEED_UPTIME; if (state->need_capacity) flags |= CRN_NEED_CAPACITY; + /* Picking the second-last node. (The last node is the relay doing the + * self-test.) */ + if (state->is_ipv6_selftest && cur_len == state->desired_path_len - 2) + flags |= CRN_INITIATE_IPV6_EXTEND;

/** If a hidden service circuit wants a specific middle node, pin it. */ if (middle_node_must_be_vanguard(options, purpose, cur_len)) { diff --git a/src/feature/nodelist/node_select.c b/src/feature/nodelist/node_select.c index 40d0f2a5b..8e7da1ae2 100644 --- a/src/feature/nodelist/node_select.c +++ b/src/feature/nodelist/node_select.c @@ -930,25 +930,33 @@ nodelist_subtract(smartlist_t *sl, const smartlist_t *excluded) bitarray_free(excluded_idx); }

-/** Return a random running node from the nodelist. Never - * pick a node that is in - * <b>excludedsmartlist</b>, or which matches <b>excludedset</b>, - * even if they are the only nodes available. - * If <b>CRN_NEED_UPTIME</b> is set in flags and any router has more than - * a minimum uptime, return one of those. - * If <b>CRN_NEED_CAPACITY</b> is set in flags, weight your choice by the - * advertised capacity of each router. - * If <b>CRN_NEED_GUARD</b> is set in flags, consider only Guard routers. - * If <b>CRN_WEIGHT_AS_EXIT</b> is set in flags, we weight bandwidths as if - * picking an exit node, otherwise we weight bandwidths for picking a relay - * node (that is, possibly discounting exit nodes). - * If <b>CRN_NEED_DESC</b> is set in flags, we only consider nodes that - * have a routerinfo or microdescriptor -- that is, enough info to be - * used to build a circuit. - * If <b>CRN_PREF_ADDR</b> is set in flags, we only consider nodes that - * have an address that is preferred by the ClientPreferIPv6ORPort setting - * (regardless of this flag, we exclude nodes that aren't allowed by the - * firewall, including ClientUseIPv4 0 and fascist_firewall_use_ipv6() == 0). +/** Return a random running node from the nodelist. Never pick a node that is + * in <b>excludedsmartlist</b>, or which matches <b>excludedset</b>, even if + * they are the only nodes available. + * + * If the following <b>flags</b> are set: + * - <b>CRN_NEED_UPTIME</b>: if any router has more than a minimum uptime, + * return one of those; + * - <b>CRN_NEED_CAPACITY</b>: weight your choice by the advertised capacity + * of each router; + * - <b>CRN_NEED_GUARD</b>: only consider Guard routers; + * - <b>CRN_WEIGHT_AS_EXIT</b>: we weight bandwidths as if picking an exit + * node, otherwise we weight bandwidths for + * picking a relay node (that is, possibly + * discounting exit nodes); + * - <b>CRN_NEED_DESC</b>: only consider nodes that have a routerinfo or + * microdescriptor -- that is, enough info to be + * used to build a circuit; + * - <b>CRN_DIRECT_CONN</b>: only consider nodes that are suitable for direct + * connections. Check ReachableAddresses, + * ClientUseIPv4 0, and + * fascist_firewall_use_ipv6() == 0); + * - <b>CRN_PREF_ADDR</b>: only consider nodes that have an address that is + * preferred by the ClientPreferIPv6ORPort setting. + * - <b>CRN_RENDEZVOUS_V3</b>: only consider nodes that can become v3 onion + * service rendezvous points. + * - <b>CRN_INITIATE_IPV6_EXTEND</b>: only consider routers than can initiate + * IPv6 extends. */ const node_t * router_choose_random_node(smartlist_t *excludedsmartlist, @@ -963,6 +971,7 @@ router_choose_random_node(smartlist_t *excludedsmartlist, const int pref_addr = (flags & CRN_PREF_ADDR) != 0; const int direct_conn = (flags & CRN_DIRECT_CONN) != 0; const int rendezvous_v3 = (flags & CRN_RENDEZVOUS_V3) != 0; + const bool initiate_ipv6_extend = (flags & CRN_INITIATE_IPV6_EXTEND) != 0;

const smartlist_t *node_list = nodelist_get_list(); smartlist_t *sl=smartlist_new(), @@ -997,7 +1006,7 @@ router_choose_random_node(smartlist_t *excludedsmartlist,

router_add_running_nodes_to_smartlist(sl, need_uptime, need_capacity, need_guard, need_desc, pref_addr, - direct_conn); + direct_conn, initiate_ipv6_extend); log_debug(LD_CIRC, "We found %d running nodes.", smartlist_len(sl)); diff --git a/src/feature/nodelist/node_select.h b/src/feature/nodelist/node_select.h index 2e67f990f..29b6e6f2c 100644 --- a/src/feature/nodelist/node_select.h +++ b/src/feature/nodelist/node_select.h @@ -28,6 +28,8 @@ typedef enum router_crn_flags_t { /* On clients, only provide nodes with HSRend >= 2 protocol version which * is required for hidden service version >= 3. */ CRN_RENDEZVOUS_V3 = 1<<9, + /* On clients, only provide nodes that can initiate IPv6 extends. */ + CRN_INITIATE_IPV6_EXTEND = 1<<10, } router_crn_flags_t;

/** Possible ways to weight routers when choosing one randomly. See diff --git a/src/feature/nodelist/routerlist.c b/src/feature/nodelist/routerlist.c index e51125626..0d3d1bea3 100644 --- a/src/feature/nodelist/routerlist.c +++ b/src/feature/nodelist/routerlist.c @@ -512,13 +512,15 @@ routers_have_same_or_addrs(const routerinfo_t *r1, const routerinfo_t *r2) }

/** Add every suitable node from our nodelist to <b>sl</b>, so that - * we can pick a node for a circuit. + * we can pick a node for a circuit. See router_choose_random_node() + * for details. */ void router_add_running_nodes_to_smartlist(smartlist_t *sl, int need_uptime, int need_capacity, int need_guard, int need_desc, int pref_addr, - int direct_conn) + int direct_conn, + bool initiate_ipv6_extend) { const int check_reach = !router_or_conn_should_skip_reachable_address_check( get_options(), @@ -545,7 +547,8 @@ router_add_running_nodes_to_smartlist(smartlist_t *sl, int need_uptime, FIREWALL_OR_CONNECTION, pref_addr)) continue; - + if (initiate_ipv6_extend && !node_supports_initiating_ipv6_extends(node)) + continue; smartlist_add(sl, (void *)node); } SMARTLIST_FOREACH_END(node); } diff --git a/src/feature/nodelist/routerlist.h b/src/feature/nodelist/routerlist.h index 401ce5e35..1297bb4b6 100644 --- a/src/feature/nodelist/routerlist.h +++ b/src/feature/nodelist/routerlist.h @@ -61,7 +61,8 @@ int routers_have_same_or_addrs(const routerinfo_t *r1, const routerinfo_t *r2); void router_add_running_nodes_to_smartlist(smartlist_t *sl, int need_uptime, int need_capacity, int need_guard, int need_desc, int pref_addr, - int direct_conn); + int direct_conn, + bool initiate_ipv6_extend);

const routerinfo_t *routerlist_find_my_routerinfo(void); uint32_t router_get_advertised_bandwidth(const routerinfo_t *router);