circuitbuild: Refactor IPv6 extend node selection

Move this complex check into its own function.

Part of 33222.
This commit is contained in:
teor 2020-05-14 22:06:14 +10:00
parent 2e41d82cc5
commit 5f577b0f25
2 changed files with 24 additions and 4 deletions

View File

@ -1999,6 +1999,26 @@ cpath_build_state_to_crn_flags(const cpath_build_state_t *state)
return flags;
}
/* Return the CRN_INITIATE_IPV6_EXTEND flag, based on <b>state</b> and
* <b>cur_len</b>.
*
* Only called for middle nodes (for now). Must not be called on single-hop
* circuits. */
STATIC int
cpath_build_state_to_crn_ipv6_extend_flag(const cpath_build_state_t *state,
int cur_len)
{
IF_BUG_ONCE(state->desired_path_len < 2)
return 0;
/* The last node is the relay doing the self-test. So we want to extend over
* IPv6 from the second-last node. */
if (state->is_ipv6_selftest && cur_len == state->desired_path_len - 2)
return CRN_INITIATE_IPV6_EXTEND;
else
return 0;
}
/** Decide a suitable length for circ's cpath, and pick an exit
* router (or use <b>exit</b> if provided). Store these in the
* cpath.
@ -2320,10 +2340,7 @@ choose_good_middle_server(uint8_t purpose,
excluded = build_middle_exclude_list(purpose, state, head, cur_len);
flags |= cpath_build_state_to_crn_flags(state);
/* 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;
flags |= cpath_build_state_to_crn_ipv6_extend_flag(state, cur_len);
/** If a hidden service circuit wants a specific middle node, pin it. */
if (middle_node_must_be_vanguard(options, purpose, cur_len)) {

View File

@ -98,6 +98,9 @@ STATIC int
onion_pick_cpath_exit(origin_circuit_t *circ, extend_info_t *exit_ei,
int is_hs_v3_rp_circuit);
STATIC int cpath_build_state_to_crn_flags(const cpath_build_state_t *state);
STATIC int cpath_build_state_to_crn_ipv6_extend_flag(
const cpath_build_state_t *state,
int cur_len);
#endif /* defined(CIRCUITBUILD_PRIVATE) */