On Fri, Feb 19, 2010 at 3:38 PM, Gert Doering <g...@greenie.muc.de> wrote: > Hi, > > On Fri, Feb 19, 2010 at 03:21:34PM +0100, JuanJo Ciarlante wrote: >> > JJO's patch does more than that, he does DNS lookups to print the >> > DNS name for the IPv6 address in question. >> >> Wrong. >> From getaddrinfo(3): >> """ >> If hints.ai_flags contains the AI_NUMERICHOST flag then the node >> parameter must be a numerical network address. >> The AI_NUMERICHOST flag suppresses any potentially lengthy >> network host address lookups. >> """ > > Ah! Learned something new today. So what's the specific advantage of > using getnameinfo() instead of inet_ntop() instead? > > (I've only ever used getnameinfo() if I really wanted to do DNS lookups). > >> > Now we enter religious >> > territory - *I* think that this is not a good thing. >> >> I can't more eagerly _agree_ on tossing out any reverse >> DNS lookups at this level. > > OK, good. Glad that this was just a misreading of the code. > > >> > The existing >> > code doesn't do reverse DNS lookups for IPv4 mroute printing, and so >> > the IPv6 code should behave similar to the IPv4 code, and not do DNS >> > either (also, depending on DNS lookup in this place might lead to >> > weird delays in unexpected situations). But this is partly religious, >> > partly "follow the coding style of the existing code" stuff. >> >> IMO we should void using inet_ntop() and friends, personally >> I don't like locking around their lack of multi-threading. > > Mmmh, ok. I wasn't aware that inet_ntop() is not thread-safe. (Looking > at the FreeBSD implementation, at least that one *is* thread-safe - no > static buffers, etc.).
And now I learned something new, by *actually* closely looking inet_ntop() manpage, heh (had a totally wrong braino on it using static buffers). Please just ignore this non MT-safe state from me. > > If it is not thread-safe, it won't break anything in my code, though > (lucky me :-) ) - my use of it in print_in6_addr() is mutex-locked anyway, > due to the use of a static buffer there. > > Is getnameinfo() *guaranteed* to be thread-safe? > > Do you have a reference that documents that inet_ntop() and inet_pton() > are unsave to be used in a threaded context? > > gert > -- > USENET is *not* the non-clickable part of WWW! > //www.muc.de/~gert/ > Gert Doering - Munich, Germany g...@greenie.muc.de > fax: +49-89-35655025 g...@net.informatik.tu-muenchen.de > -- --JuanJo ; echo j...@gomosglep.com | sed 's/[SPAM]//g'
