From: Michael Stapelberg <michael@stapelberg.de>
Date: Fri, 28 Sep 2012 22:08:56 +0000 (+0200)
Subject: Save the DNS lookup for K.root-servers.net (Thanks barfoos)
X-Git-Tag: 2.6~2
X-Git-Url: https://git.sur5r.net/?p=i3%2Fi3status;a=commitdiff_plain;h=5c615f70749811acdb64a6821d8143c61d65a583

Save the DNS lookup for K.root-servers.net (Thanks barfoos)

This avoids running into a timeout when there is no connectivity on
i3status startup.
---

diff --git a/src/print_ipv6_addr.c b/src/print_ipv6_addr.c
index abf4508..8b11e1f 100644
--- a/src/print_ipv6_addr.c
+++ b/src/print_ipv6_addr.c
@@ -78,10 +78,13 @@ static char *get_ipv6_addr(void) {
         hints.ai_family = AF_INET6;
         hints.ai_socktype = SOCK_DGRAM;
 
-        /* We resolve the K root server to get a public IPv6 address. You can
-         * replace this with any other host which has an AAAA record, but the
-         * K root server is a pretty safe bet. */
-        if (getaddrinfo("k.root-servers.net", "domain", &hints, &result) != 0) {
+        /* We use the public IPv6 of the K root server here. It doesn’t matter
+         * which IPv6 address we use (we don’t even send any packets), as long
+         * as it’s considered global by the kernel.
+         * NB: We don’t use a hostname since that would trigger a DNS lookup.
+         * By using an IPv6 address, getaddrinfo() will *not* do a DNS lookup,
+         * but return the address in the appropriate struct. */
+        if (getaddrinfo("2001:7fd::1", "domain", &hints, &result) != 0) {
                 /* We don’t display the error here because most
                  * likely, there just is no connectivity.
                  * Thus, don’t spam the user’s console. */