From 1cd417bdf10366d63cc875e285c6418709a58c17 Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Thu, 25 Jul 2013 03:20:02 -0400 Subject: [PATCH] make inet_ntop format v4-mapped ipv6 addresses properly based on a patch by orc. POSIX actually fails to specify the format of the ntop conversion; presumably, any output that will correctly round-trip back via the (well-specified) pton operation is acceptable. the new behavior is much more convenient than the old, however. this patch also affects getnameinfo, which is implemented in terms of inet_ntop and which is the preferred interface for performing this conversion. I've also removed some inexplicable cruft (filling the buffer with 'x' before doing anything) whose origin I was unable to track down. --- src/network/inet_ntop.c | 22 ++++++++++++++-------- 1 file changed, 14 insertions(+), 8 deletions(-) diff --git a/src/network/inet_ntop.c b/src/network/inet_ntop.c index 76ae556c..e9e2823f 100644 --- a/src/network/inet_ntop.c +++ b/src/network/inet_ntop.c @@ -18,14 +18,20 @@ const char *inet_ntop(int af, const void *restrict a0, char *restrict s, socklen return s; break; case AF_INET6: - memset(buf, 'x', sizeof buf); - buf[sizeof buf-1]=0; - snprintf(buf, sizeof buf, - "%x:%x:%x:%x:%x:%x:%x:%x", - 256*a[0]+a[1],256*a[2]+a[3], - 256*a[4]+a[5],256*a[6]+a[7], - 256*a[8]+a[9],256*a[10]+a[11], - 256*a[12]+a[13],256*a[14]+a[15]); + if (memcmp(a, "\0\0\0\0\0\0\0\0\0\0\377\377", 12)) + snprintf(buf, sizeof buf, + "%x:%x:%x:%x:%x:%x:%x:%x", + 256*a[0]+a[1],256*a[2]+a[3], + 256*a[4]+a[5],256*a[6]+a[7], + 256*a[8]+a[9],256*a[10]+a[11], + 256*a[12]+a[13],256*a[14]+a[15]); + else + snprintf(buf, sizeof buf, + "%x:%x:%x:%x:%x:%x:%d.%d.%d.%d", + 256*a[0]+a[1],256*a[2]+a[3], + 256*a[4]+a[5],256*a[6]+a[7], + 256*a[8]+a[9],256*a[10]+a[11], + a[12],a[13],a[14],a[15]); /* Replace longest /(^0|:)[:0]{2,}/ with "::" */ for (i=best=0, max=2; buf[i]; i++) { if (i && buf[i] != ':') continue; -- 2.25.1