Update copyright notice

[empserver] / src / lib / gen / tcp_listen.c

diff --git a/src/lib/gen/tcp_listen.c b/src/lib/gen/tcp_listen.c
index f2ec86d090ed692f70f3ed666036eae1d09ad1d9..a3ef26cc590628b75d59a75576e1601df0d1c669 100644 (file)
--- a/src/lib/gen/tcp_listen.c
+++ b/src/lib/gen/tcp_listen.c
@@ -1,6 +1,6 @@
 /*
  *  Empire - A multi-player, client/server Internet based war game.
- *  Copyright (C) 1986-2013, Dave Pare, Jeff Bailey, Thomas Ruschak,
+ *  Copyright (C) 1986-2015, Dave Pare, Jeff Bailey, Thomas Ruschak,
  *                Ken Stevens, Steve McClure, Markus Armbruster
  *
  *  Empire is free software: you can redistribute it and/or modify
@@ -27,7 +27,7 @@
  *  tcp_listen.c: Create a socket and listen on it
  *
  *  Known contributors to this file:
- *     Markus Armbruster, 2005-2010
+ *     Markus Armbruster, 2005-2013
  */
 
 #include <config.h>
@@ -66,6 +66,8 @@ tcp_listen(char *host, char *serv, size_t *addrlenp)
      */
     int err;
     struct addrinfo hints, *first_ai, *ai;
+    /* Crap necessary for OpenBSD, see below */
+    int try_v6only_off = 1, v6only_stuck = 0;
 
     memset(&hints, 0, sizeof(struct addrinfo));
     hints.ai_flags = AI_PASSIVE | AI_ADDRCONFIG;
@@ -76,17 +78,32 @@ tcp_listen(char *host, char *serv, size_t *addrlenp)
        cant_listen(host, serv, gai_strerror(err));
     assert(first_ai);
 
+again:
     for (ai = first_ai; ai; ai = ai->ai_next) {
        fd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
        if (fd < 0)
            continue;           /* error, try next one */
 
 #ifdef IPV6_V6ONLY
-       if (ai->ai_family == AF_INET6) {
+       if (ai->ai_family == AF_INET6 && try_v6only_off) {
            int off = 0;
 
-           setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, &off, sizeof(off));
+           if (setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY,
+                          &off, sizeof(off)) < 0) {
+               /*
+                * IPV6_V6ONLY is stuck on, violating RFC 3493 (gee,
+                * thanks, OpenBSD!).  Address is good only for IPv6,
+                * not for IPv4.  Means we can't have both on this
+                * system.  Continue looking for one that's good for
+                * IPv4.
+                */
+               v6only_stuck = 1;
+               close(fd);
+               continue;
+           }
        }
+#else
+       (void)try_v6only_off;
 #endif
 
        setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));
@@ -96,6 +113,17 @@ tcp_listen(char *host, char *serv, size_t *addrlenp)
        close(fd);              /* error, close and try next one */
     }
 
+    /* More crap for OpenBSD */
+    if (ai == NULL && v6only_stuck) {
+       /*
+        * No go.  But we skipped IPv6 addresses that don't work for
+        * IPv4, but could for IPv6.  Try again without skipping
+        * these.
+        */
+       try_v6only_off = 0;
+       goto again;
+    }
+
     if (ai == NULL)         /* errno from final socket() or bind() */
        cant_listen(host, serv, strerror(errno));