+char *
+bestmx_map_lookup(map, name, av, statp)
+ MAP *map;
+ char *name;
+ char **av;
+ int *statp;
+{
+ int nmx;
+ auto int rcode;
+ int saveopts = _res.options;
+ char *mxhosts[MAXMXHOSTS + 1];
+
+ _res.options &= ~(RES_DNSRCH|RES_DEFNAMES);
+ nmx = getmxrr(name, mxhosts, FALSE, &rcode);
+ _res.options = saveopts;
+ if (nmx <= 0)
+ return NULL;
+ if (bitset(MF_MATCHONLY, map->map_mflags))
+ return map_rewrite(map, name, strlen(name), NULL);
+ else
+ return map_rewrite(map, mxhosts[0], strlen(mxhosts[0]), av);
+}
+\f/*
+** DNS_GETCANONNAME -- get the canonical name for named host using DNS
+**
+** This algorithm tries to be smart about wildcard MX records.
+** This is hard to do because DNS doesn't tell is if we matched
+** against a wildcard or a specific MX.
+**
+** We always prefer A & CNAME records, since these are presumed
+** to be specific.
+**
+** If we match an MX in one pass and lose it in the next, we use
+** the old one. For example, consider an MX matching *.FOO.BAR.COM.
+** A hostname bletch.foo.bar.com will match against this MX, but
+** will stop matching when we try bletch.bar.com -- so we know
+** that bletch.foo.bar.com must have been right. This fails if
+** there was also an MX record matching *.BAR.COM, but there are
+** some things that just can't be fixed.
+**
+** Parameters:
+** host -- a buffer containing the name of the host.
+** This is a value-result parameter.
+** hbsize -- the size of the host buffer.
+** trymx -- if set, try MX records as well as A and CNAME.
+** statp -- pointer to place to store status.
+**
+** Returns:
+** TRUE -- if the host matched.
+** FALSE -- otherwise.
+*/
+
+bool
+dns_getcanonname(host, hbsize, trymx, statp)
projects / unix-history / blobdiff