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Prop#329 Pool: Avoid sharing Guards and Middles between circuits.
Conflux must not use the same Guard for each leg; nor the same middle for each leg.
This commit is contained in:
parent
336a24754d
commit
46e473f43e
@ -45,6 +45,7 @@
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#include "core/or/command.h"
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#include "core/or/connection_edge.h"
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#include "core/or/connection_or.h"
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#include "core/or/conflux_pool.h"
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#include "core/or/extendinfo.h"
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#include "core/or/onion.h"
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#include "core/or/ocirc_event.h"
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@ -89,7 +90,8 @@ static int circuit_send_first_onion_skin(origin_circuit_t *circ);
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static int circuit_build_no_more_hops(origin_circuit_t *circ);
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static int circuit_send_intermediate_onion_skin(origin_circuit_t *circ,
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crypt_path_t *hop);
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static const node_t *choose_good_middle_server(uint8_t purpose,
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static const node_t *choose_good_middle_server(const origin_circuit_t *,
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uint8_t purpose,
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cpath_build_state_t *state,
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crypt_path_t *head,
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int cur_len);
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@ -2313,7 +2315,8 @@ build_vanguard_middle_exclude_list(uint8_t purpose,
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* hop, based on already chosen nodes.
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*/
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static smartlist_t *
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build_middle_exclude_list(uint8_t purpose,
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build_middle_exclude_list(const origin_circuit_t *circ,
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uint8_t purpose,
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cpath_build_state_t *state,
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crypt_path_t *head,
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int cur_len)
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@ -2330,6 +2333,9 @@ build_middle_exclude_list(uint8_t purpose,
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excluded = smartlist_new();
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// Exclude other middles on pending and built conflux circs
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conflux_add_middles_to_exclude_list(circ, excluded);
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/* For non-vanguard circuits, add the exit and its family to the exclude list
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* (note that the exit/last hop is always chosen first in
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* circuit_establish_circuit()). */
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@ -2423,7 +2429,8 @@ pick_vanguard_middle_node(const or_options_t *options,
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* family, and make sure we don't duplicate any previous nodes or their
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* families. */
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static const node_t *
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choose_good_middle_server(uint8_t purpose,
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choose_good_middle_server(const origin_circuit_t * circ,
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uint8_t purpose,
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cpath_build_state_t *state,
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crypt_path_t *head,
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int cur_len)
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@ -2438,7 +2445,7 @@ choose_good_middle_server(uint8_t purpose,
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log_debug(LD_CIRC, "Contemplating intermediate hop #%d: random choice.",
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cur_len+1);
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excluded = build_middle_exclude_list(purpose, state, head, cur_len);
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excluded = build_middle_exclude_list(circ, purpose, state, head, cur_len);
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flags |= cpath_build_state_to_crn_flags(state);
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flags |= cpath_build_state_to_crn_ipv6_extend_flag(state, cur_len);
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@ -2483,7 +2490,8 @@ choose_good_middle_server(uint8_t purpose,
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* guard worked or not.
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*/
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const node_t *
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choose_good_entry_server(uint8_t purpose, cpath_build_state_t *state,
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choose_good_entry_server(const origin_circuit_t *circ,
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uint8_t purpose, cpath_build_state_t *state,
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circuit_guard_state_t **guard_state_out)
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{
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const node_t *choice;
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@ -2505,7 +2513,7 @@ choose_good_entry_server(uint8_t purpose, cpath_build_state_t *state,
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/* This request is for an entry server to use for a regular circuit,
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* and we use entry guard nodes. Just return one of the guard nodes. */
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tor_assert(guard_state_out);
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return guards_choose_guard(state, purpose, guard_state_out);
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return guards_choose_guard(circ, state, purpose, guard_state_out);
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}
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excluded = smartlist_new();
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@ -2551,7 +2559,7 @@ onion_extend_cpath(origin_circuit_t *circ)
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if (cur_len == state->desired_path_len - 1) { /* Picking last node */
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info = extend_info_dup(state->chosen_exit);
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} else if (cur_len == 0) { /* picking first node */
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const node_t *r = choose_good_entry_server(purpose, state,
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const node_t *r = choose_good_entry_server(circ, purpose, state,
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&circ->guard_state);
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if (r) {
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/* If we're a client, use the preferred address rather than the
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@ -2564,7 +2572,7 @@ onion_extend_cpath(origin_circuit_t *circ)
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}
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} else {
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const node_t *r =
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choose_good_middle_server(purpose, state, circ->cpath, cur_len);
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choose_good_middle_server(circ, purpose, state, circ->cpath, cur_len);
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if (r) {
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info = extend_info_from_node(r, 0, false);
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}
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@ -57,7 +57,8 @@ const char *build_state_get_exit_nickname(cpath_build_state_t *state);
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struct circuit_guard_state_t;
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const node_t *choose_good_entry_server(uint8_t purpose,
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const node_t *choose_good_entry_server(const origin_circuit_t *circ,
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uint8_t purpose,
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cpath_build_state_t *state,
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struct circuit_guard_state_t **guard_state_out);
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void circuit_upgrade_circuits_from_guard_wait(void);
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@ -31,6 +31,8 @@
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#include "core/or/crypt_path_st.h"
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#include "core/or/or_circuit_st.h"
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#include "core/or/origin_circuit_st.h"
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#include "core/or/extend_info_st.h"
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#include "core/or/conflux_st.h"
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#include "feature/nodelist/nodelist.h"
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@ -1092,6 +1094,127 @@ conflux_launch_leg(const uint8_t *nonce)
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return false;
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}
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/**
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* Add the identity digest of the guard nodes of all legs of the conflux
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* circuit.
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*
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* This function checks both pending and linked conflux circuits.
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*/
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void
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conflux_add_guards_to_exclude_list(const origin_circuit_t *orig_circ,
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smartlist_t *excluded)
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{
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tor_assert(orig_circ);
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tor_assert(excluded);
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/* Ease our lives. */
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const circuit_t *circ = TO_CIRCUIT(orig_circ);
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/* Ignore if this is not conflux related. */
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if (!CIRCUIT_IS_CONFLUX(circ)) {
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return;
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}
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/* When building a circuit, we should not have a conflux object
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* ourselves (though one may exist elsewhere). */
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tor_assert(!circ->conflux);
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/* Getting here without a nonce is a code flow issue. */
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if (BUG(!circ->conflux_pending_nonce)) {
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return;
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}
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/* A linked set exists, use it. */
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const conflux_t *cfx = linked_pool_get(circ->conflux_pending_nonce, true);
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if (cfx) {
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CONFLUX_FOR_EACH_LEG_BEGIN(cfx, leg) {
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const origin_circuit_t *ocirc = CONST_TO_ORIGIN_CIRCUIT(leg->circ);
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smartlist_add(excluded,
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tor_memdup(ocirc->cpath->extend_info->identity_digest,
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DIGEST_LEN));
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} CONFLUX_FOR_EACH_LEG_END(leg);
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}
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/* An unlinked set might exist for this nonce, if so, add the second hop of
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* the existing legs to the exclusion list. */
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unlinked_circuits_t *unlinked =
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unlinked_pool_get(circ->conflux_pending_nonce, true);
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if (unlinked) {
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tor_assert(unlinked->is_client);
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SMARTLIST_FOREACH_BEGIN(unlinked->legs, leg_t *, leg) {
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/* Convert to origin circ and get cpath */
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const origin_circuit_t *ocirc = CONST_TO_ORIGIN_CIRCUIT(leg->circ);
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smartlist_add(excluded,
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tor_memdup(ocirc->cpath->extend_info->identity_digest,
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DIGEST_LEN));
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} SMARTLIST_FOREACH_END(leg);
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}
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}
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/**
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* Add the identity digest of the middle nodes of all legs of the conflux
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* circuit.
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*
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* This function checks both pending and linked conflux circuits.
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*
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* XXX: The add guard and middle could be merged since it is the exact same
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* code except for the cpath position and the identity digest vs node_t in
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* the list. We could use an extra param indicating guard or middle. */
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void
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conflux_add_middles_to_exclude_list(const origin_circuit_t *orig_circ,
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smartlist_t *excluded)
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{
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tor_assert(orig_circ);
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tor_assert(excluded);
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/* Ease our lives. */
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const circuit_t *circ = TO_CIRCUIT(orig_circ);
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/* Ignore if this is not conflux related. */
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if (!CIRCUIT_IS_CONFLUX(circ)) {
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return;
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}
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/* When building a circuit, we should not have a conflux object
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* ourselves (though one may exist elsewhere). */
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tor_assert(!circ->conflux);
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/* Getting here without a nonce is a code flow issue. */
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if (BUG(!circ->conflux_pending_nonce)) {
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return;
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}
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/* A linked set exists, use it. */
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const conflux_t *cfx = linked_pool_get(circ->conflux_pending_nonce, true);
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if (cfx) {
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CONFLUX_FOR_EACH_LEG_BEGIN(cfx, leg) {
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const origin_circuit_t *ocirc = CONST_TO_ORIGIN_CIRCUIT(leg->circ);
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node_t *node = node_get_mutable_by_id(
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ocirc->cpath->next->extend_info->identity_digest);
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if (node) {
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smartlist_add(excluded, node);
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}
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} CONFLUX_FOR_EACH_LEG_END(leg);
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}
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/* An unlinked set might exist for this nonce, if so, add the second hop of
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* the existing legs to the exclusion list. */
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unlinked_circuits_t *unlinked =
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unlinked_pool_get(circ->conflux_pending_nonce, true);
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if (unlinked) {
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tor_assert(unlinked->is_client);
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SMARTLIST_FOREACH_BEGIN(unlinked->legs, leg_t *, leg) {
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/* Convert to origin circ and get cpath */
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const origin_circuit_t *ocirc = CONST_TO_ORIGIN_CIRCUIT(leg->circ);
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node_t *node = node_get_mutable_by_id(
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ocirc->cpath->next->extend_info->identity_digest);
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if (node) {
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smartlist_add(excluded, node);
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}
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} SMARTLIST_FOREACH_END(leg);
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}
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}
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/** The given circuit is conflux pending and has closed. This deletes the leg
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* from the set, attempt to finalize it and relaunch a new leg. If the set is
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* empty after removing this leg, it is deleted. */
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@ -21,6 +21,11 @@ void conflux_predict_new(time_t now);
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bool conflux_launch_leg(const uint8_t *nonce);
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void conflux_add_guards_to_exclude_list(const origin_circuit_t *circ,
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smartlist_t *excluded);
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void conflux_add_middles_to_exclude_list(const origin_circuit_t *circ,
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smartlist_t *excluded);
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void conflux_circuit_has_closed(circuit_t *circ);
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void conflux_circuit_has_opened(origin_circuit_t *orig_circ);
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void conflux_circuit_about_to_free(circuit_t *circ);
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@ -126,6 +126,7 @@
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#include "core/or/circuitlist.h"
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#include "core/or/circuitstats.h"
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#include "core/or/circuituse.h"
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#include "core/or/conflux_pool.h"
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#include "core/or/policies.h"
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#include "feature/client/bridges.h"
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#include "feature/client/circpathbias.h"
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@ -151,6 +152,8 @@
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#include "core/or/origin_circuit_st.h"
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#include "app/config/or_state_st.h"
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#include "core/or/conflux_util.h"
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/** A list of existing guard selection contexts. */
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static smartlist_t *guard_contexts = NULL;
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/** The currently enabled guard selection context. */
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@ -1588,6 +1591,19 @@ guard_create_exit_restriction(const uint8_t *exit_id)
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return rst;
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}
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/* Allocate and return a new exit guard restriction that excludes all current
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* and pending conflux guards */
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STATIC entry_guard_restriction_t *
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guard_create_conflux_restriction(const origin_circuit_t *circ)
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{
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entry_guard_restriction_t *rst = NULL;
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rst = tor_malloc_zero(sizeof(entry_guard_restriction_t));
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rst->type = RST_EXCL_LIST;
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rst->excluded = smartlist_new();
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conflux_add_guards_to_exclude_list(circ, rst->excluded);
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return rst;
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}
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/** If we have fewer than this many possible usable guards, don't set
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* MD-availability-based restrictions: we might denylist all of them. */
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#define MIN_GUARDS_FOR_MD_RESTRICTION 10
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@ -1680,6 +1696,8 @@ entry_guard_obeys_restriction(const entry_guard_t *guard,
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return guard_obeys_exit_restriction(guard, rst);
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} else if (rst->type == RST_OUTDATED_MD_DIRSERVER) {
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return guard_obeys_md_dirserver_restriction(guard);
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} else if (rst->type == RST_EXCL_LIST) {
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return !smartlist_contains_digest(rst->excluded, guard->identity);
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}
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tor_assert_nonfatal_unreached();
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@ -2427,6 +2445,11 @@ entry_guard_has_higher_priority(entry_guard_t *a, entry_guard_t *b)
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STATIC void
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entry_guard_restriction_free_(entry_guard_restriction_t *rst)
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{
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if (rst && rst->excluded) {
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SMARTLIST_FOREACH(rst->excluded, void *, g,
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tor_free(g));
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smartlist_free(rst->excluded);
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}
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tor_free(rst);
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}
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@ -3780,7 +3803,8 @@ guards_update_all(void)
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/** Helper: pick a guard for a circuit, with whatever algorithm is
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used. */
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const node_t *
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guards_choose_guard(cpath_build_state_t *state,
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guards_choose_guard(const origin_circuit_t *circ,
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cpath_build_state_t *state,
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uint8_t purpose,
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circuit_guard_state_t **guard_state_out)
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{
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@ -3788,14 +3812,18 @@ guards_choose_guard(cpath_build_state_t *state,
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const uint8_t *exit_id = NULL;
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entry_guard_restriction_t *rst = NULL;
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/* Only apply restrictions if we have a specific exit node in mind, and only
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* if we are not doing vanguard circuits: we don't want to apply guard
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* restrictions to vanguard circuits. */
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if (state && !circuit_should_use_vanguards(purpose) &&
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/* If we this is a conflux circuit, build an exclusion list for it. */
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if (CIRCUIT_IS_CONFLUX(TO_CIRCUIT(circ))) {
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rst = guard_create_conflux_restriction(circ);
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/* Don't allow connecting back to the exit if there is one */
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if (state && (exit_id = build_state_get_exit_rsa_id(state))) {
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/* add the exit_id to the excluded list */
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smartlist_add(rst->excluded, tor_memdup(exit_id, DIGEST_LEN));
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}
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} else if (state && !circuit_should_use_vanguards(purpose) &&
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(exit_id = build_state_get_exit_rsa_id(state))) {
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/* We're building to a targeted exit node, so that node can't be
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* chosen as our guard for this circuit. Remember that fact in a
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* restriction. */
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* chosen as our guard for this circuit, unless we're vanguards. */
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rst = guard_create_exit_restriction(exit_id);
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tor_assert(rst);
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}
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@ -294,7 +294,9 @@ typedef enum guard_restriction_type_t {
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/* Don't pick the same guard node as our exit node (or its family) */
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RST_EXIT_NODE = 0,
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/* Don't pick dirguards that have previously shown to be outdated */
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RST_OUTDATED_MD_DIRSERVER = 1
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RST_OUTDATED_MD_DIRSERVER = 1,
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/* Don't pick guards if they are in the exclusion list */
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RST_EXCL_LIST = 2,
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} guard_restriction_type_t;
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/**
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@ -312,6 +314,10 @@ struct entry_guard_restriction_t {
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* digest must not equal this; and it must not be in the same family as any
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* node with this digest. */
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uint8_t exclude_id[DIGEST_LEN];
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/* In the case of RST_EXCL_LIST, any identity digests in this list
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* must not be used. */
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smartlist_t *excluded;
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};
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/**
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@ -337,7 +343,8 @@ struct circuit_guard_state_t {
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/* Common entry points for old and new guard code */
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int guards_update_all(void);
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const node_t *guards_choose_guard(cpath_build_state_t *state,
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const node_t *guards_choose_guard(const origin_circuit_t *circ,
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cpath_build_state_t *state,
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uint8_t purpose,
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circuit_guard_state_t **guard_state_out);
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const node_t *guards_choose_dirguard(uint8_t dir_purpose,
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@ -597,6 +604,9 @@ STATIC entry_guard_restriction_t *guard_create_exit_restriction(
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STATIC entry_guard_restriction_t *guard_create_dirserver_md_restriction(void);
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STATIC entry_guard_restriction_t * guard_create_conflux_restriction(
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const origin_circuit_t *circ);
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STATIC void entry_guard_restriction_free_(entry_guard_restriction_t *rst);
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#define entry_guard_restriction_free(rst) \
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FREE_AND_NULL(entry_guard_restriction_t, \
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