From 4a07ea4a8c41c55ef4d8341ddf67601d3f09711a Mon Sep 17 00:00:00 2001 From: Nick Mathewson Date: Sun, 25 Nov 2012 17:19:25 -0500 Subject: Drop the maximum attempts to get a virtual address to 1000. This is good enough to give P_success >= 999,999,999/1,000,000,000 so long as the address space is less than 97.95 full. It'd be ridiculous for that to happen for IPv6, and usome reasonable assumptions, it would also be pretty silly for IPv4. --- src/or/addressmap.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) (limited to 'src/or') diff --git a/src/or/addressmap.c b/src/or/addressmap.c index e1efbf4bfd..f4c31295a8 100644 --- a/src/or/addressmap.c +++ b/src/or/addressmap.c @@ -863,9 +863,13 @@ addressmap_get_virtual_address(int type) const virtual_addr_conf_t *conf = ipv6 ? &virtaddr_conf_ipv6 : &virtaddr_conf_ipv4; - // This is an imperfect estimate of how many addresses are available, but - // that's ok. We also don't try every one. - uint32_t attempts = ipv6 ? UINT32_MAX : (1u << (32- conf->bits)); + /* Don't try more than 1000 times. This gives us P < 1e-9 for + * failing to get a good address so long as the address space is + * less than ~97.95% full. That's always going to be true under + * sensible circumstances for an IPv6 /10, and it's going to be + * true for an IPv4 /10 as long as we've handed out less than + * 4.08 million addresses. */ + uint32_t attempts = 1000; tor_addr_t addr; -- cgit v1.2.3-54-g00ecf