commit 89c4a3a0b6f824841ab03d39ca59acc73a80b728 Author: rl1987 <rl1987@sdf.lonestar.org> Date: Mon Oct 15 16:13:22 2018 +0300 Write a comment to explain may_need_rebind condition --- src/core/mainloop/connection.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/src/core/mainloop/connection.c b/src/core/mainloop/connection.c index 5ebfac6be..5c0799fbe 100644 --- a/src/core/mainloop/connection.c +++ b/src/core/mainloop/connection.c @@ -2797,6 +2797,15 @@ retry_listener_ports(smartlist_t *old_conns, break; } #ifdef ENABLE_LISTENER_REBIND + /* Rebinding may be needed if all of the following are true: + * 1) Address family is the same in old and new listeners. + * 2) Port number matches exactly (numeric value is the same). + * 3) *One* of listeners (either old one or new one) has a + * wildcard IP address (0.0.0.0 or [::]). + * + * These are the exact conditions for a first bind() syscall + * to fail with EADDRINUSE. + */ const int may_need_rebind = tor_addr_family(&wanted->addr) == tor_addr_family(&conn->addr) && port_matches_exact && bool_neq(tor_addr_is_null(&wanted->addr),