Add DNS API.

Missing functional tests. I'm not sure how to do tests because I don't want
to rely on the fact that users have an internet connection.

LICENSE

@@ -22,6 +22,10 @@ are:
   - The SCONS build system, located at tools/scons. Copyrighted by the SCONS
     Foundation.  Released under an MIT license.
 
+  - UDNS, an asynchronous DNS client, located at deps/udns. Copyrighted by
+    Michael Tokarev <mjt@corpit.ru>. Released under the GNU Lesser General
+    Public License version 2.1.
+
 Additionally deps/http_parser is based on Zed Shaw's Mongrel.  Mongrel is
 copyrighted by Zed Shaw and distributed under GPL2 or a permissive open
 licence. See deps/http_parser/LICENCE for more information.

deps/udns/.cvsignore

@@ -0,0 +1,14 @@
+udns*.tar.gz
+udns_codes.c
+udns.3.html
+*.lo
+*_s
+libudns.so.*
+dnsget
+ex-rdns
+rblcheck
+Makefile
+config.h
+config.status
+config.log
+build-stamp

deps/udns/Makefile.in

@@ -0,0 +1,196 @@
+#! /usr/bin/make -rf
+# $Id: Makefile.in,v 1.11 2007/01/15 21:19:08 mjt Exp $
+# libudns Makefile
+#
+# Copyright (C) 2005  Michael Tokarev <mjt@corpit.ru>
+# This file is part of UDNS library, an async DNS stub resolver.
+#
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+#
+# This library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this library, in file named COPYING.LGPL; if not,
+# write to the Free Software Foundation, Inc., 59 Temple Place,
+# Suite 330, Boston, MA  02111-1307  USA
+
+NAME   = udns
+VERS   = 0.0.9
+SRCS   = udns_dn.c udns_dntosp.c udns_parse.c udns_resolver.c udns_init.c \
+	udns_misc.c udns_XtoX.c \
+	udns_rr_a.c udns_rr_ptr.c udns_rr_mx.c udns_rr_txt.c udns_bl.c \
+	udns_rr_srv.c udns_rr_naptr.c udns_codes.c
+USRCS  = dnsget.c rblcheck.c ex-rdns.c
+DEB    = debian/copyright debian/changelog debian/control debian/rules
+DIST   = COPYING.LGPL udns.h udns.3 dnsget.1 rblcheck.1 $(SRCS) $(USRCS) \
+	 NEWS TODO NOTES Makefile.in configure configure.lib \
+	 inet_XtoX.c getopt.c
+
+OBJS   = $(SRCS:.c=.o) $(GEN:.c=.o)
+LIB    = lib$(NAME).a
+LIBFL  = -L. -l$(NAME)
+
+SOVER  = 0
+SOBJS  = $(OBJS:.o=.lo)
+SOLIB  = lib$(NAME)_s.so
+SOLIBV = lib$(NAME).so.$(SOVER)
+SOLIBFL= -L. -l$(NAME)_s
+
+LIBS   = $(LIB) $(SOLIBV)
+
+UTILS   = $(USRCS:.c=)
+UOBJS   = $(USRCS:.c=.o)
+SOUTILS = $(USRCS:.c=_s)
+
+NAMEPFX = $(NAME)-$(VERS)
+
+CC = @CC@
+CFLAGS = @CFLAGS@
+CDEFS = @CDEFS@
+PICFLAGS = -fPIC
+AWK = awk
+
+all: static
+
+.SUFFIXES: .c .o .lo
+
+static: $(LIB) $(UTILS)
+staticlib: $(LIB)
+$(LIB): $(OBJS)
+	-rm -f $@
+	$(AR) rv $@ $(OBJS)
+.c.o:
+	$(CC) $(CFLAGS) $(CDEFS) -c $<
+
+shared: $(SOLIBV) $(SOUTILS)
+sharedlib: $(SOLIBV)
+
+$(SOLIBV): $(SOBJS)
+	$(CC) -shared -Wl,--soname,$(SOLIBV) -o $@ $(SOBJS)
+$(SOLIB): $(SOLIBV)
+	rm -f $@
+	ln -s $(SOLIBV) $@
+.c.lo:
+	$(CC) $(CFLAGS) $(PICFLAGS) $(CDEFS) -o $@ -c $<
+
+# udns_codes.c is generated from udns.h
+udns_codes.c: udns.h
+	@echo Generating $@
+	@set -e; exec >$@.tmp; \
+	set T type C class R rcode; \
+	echo "/* Automatically generated. */"; \
+	echo "#include \"udns.h\""; \
+	while [ "$$1" ]; do \
+	 echo; \
+	 echo "const struct dns_nameval dns_$${2}tab[] = {"; \
+	 $(AWK) "/^  DNS_$${1}_[A-Z0-9_]+[ 	]*=/ \
+	  { printf \" {%s,\\\"%s\\\"},\\n\", \$$1, substr(\$$1,7) }" \
+	  udns.h ; \
+	 echo " {0,0}};"; \
+	 echo "const char *dns_$${2}name(enum dns_$${2} code) {"; \
+	 echo " static char nm[20];"; \
+	 echo " switch(code) {"; \
+	 $(AWK) "BEGIN{i=0} \
+	   /^  DNS_$${1}_[A-Z0-9_]+[ 	]*=/ \
+	   {printf \" case %s: return dns_$${2}tab[%d].name;\\n\",\$$1,i++}\
+	   " udns.h ; \
+	 echo " }"; \
+	 echo " return _dns_format_code(nm,\"$$2\",code);"; \
+	 echo "}"; \
+	 shift 2; \
+	done
+	@mv $@.tmp $@
+
+udns.3.html: udns.3
+	groff -man -Thtml udns.3 > $@.tmp
+	mv $@.tmp $@
+
+dist: $(NAMEPFX).tar.gz
+$(NAMEPFX).tar.gz: $(DIST) $(DEB)
+	mkdir $(NAMEPFX) $(NAMEPFX)/debian
+	ln $(DIST) $(NAMEPFX)
+	ln $(DEB) $(NAMEPFX)/debian
+	tar cvfz $@ $(NAMEPFX)
+	rm -rf $(NAMEPFX)
+subdist:
+	cp -p $(DIST) $(TARGET)/
+
+clean:
+	rm -f $(OBJS)
+	rm -f $(SOBJS)
+	rm -f $(UOBJS)
+	rm -f build-stamp config.log
+distclean: clean
+	rm -f $(LIBS) $(SOLIB) udns.3.html
+	rm -f $(UTILS) $(SOUTILS)
+	rm -f config.status config.h Makefile
+
+
+Makefile: configure configure.lib Makefile.in
+	./configure
+	@echo
+	@echo Please rerun make >&2
+	@exit 1
+
+.PHONY: all static staticlib shared sharedlib dist clean distclean subdist \
+  depend dep deps
+
+depend dep deps: $(SRCS) $(USRC)
+	@echo Generating deps for:
+	@echo \ $(SRCS)
+	@echo \ $(USRCS)
+	@sed '/^# depend/q' Makefile.in > Makefile.tmp
+	@set -e; \
+	for f in $(SRCS) $(USRCS); do \
+	 echo $${f%.c}.o $${f%.c}.lo: $$f \
+	  `sed -n 's/^#[ 	]*include[ 	]*"\(.*\)".*/\1/p' $$f`; \
+	done >> Makefile.tmp; \
+	for f in $(USRCS:.c=.o); do \
+	 echo "$${f%.?}: $$f \$$(LIB)"; \
+	 echo "	\$$(CC) \$$(CFLAGS) -o \$$@ $$f \$$(LIBFL)"; \
+	 echo "$${f%.?}_s: $$f \$$(SOLIB)"; \
+	 echo "	\$$(CC) \$$(CFLAGS) -o \$$@ $$f \$$(SOLIBFL)"; \
+	done >> Makefile.tmp ; \
+	if cmp Makefile.tmp Makefile.in >/dev/null 2>&1 ; then \
+	 echo Makefile.in unchanged; rm -f Makefile.tmp; \
+	else \
+	 echo Updating Makfile.in; mv -f Makefile.tmp Makefile.in ; \
+	fi
+
+# depend
+udns_dn.o udns_dn.lo: udns_dn.c udns.h
+udns_dntosp.o udns_dntosp.lo: udns_dntosp.c udns.h
+udns_parse.o udns_parse.lo: udns_parse.c udns.h
+udns_resolver.o udns_resolver.lo: udns_resolver.c config.h udns.h
+udns_init.o udns_init.lo: udns_init.c config.h udns.h
+udns_misc.o udns_misc.lo: udns_misc.c udns.h
+udns_XtoX.o udns_XtoX.lo: udns_XtoX.c config.h udns.h inet_XtoX.c
+udns_rr_a.o udns_rr_a.lo: udns_rr_a.c udns.h
+udns_rr_ptr.o udns_rr_ptr.lo: udns_rr_ptr.c udns.h
+udns_rr_mx.o udns_rr_mx.lo: udns_rr_mx.c udns.h
+udns_rr_txt.o udns_rr_txt.lo: udns_rr_txt.c udns.h
+udns_bl.o udns_bl.lo: udns_bl.c udns.h
+udns_rr_srv.o udns_rr_srv.lo: udns_rr_srv.c udns.h
+udns_rr_naptr.o udns_rr_naptr.lo: udns_rr_naptr.c udns.h
+udns_codes.o udns_codes.lo: udns_codes.c udns.h
+dnsget.o dnsget.lo: dnsget.c config.h udns.h getopt.c
+rblcheck.o rblcheck.lo: rblcheck.c udns.h getopt.c
+ex-rdns.o ex-rdns.lo: ex-rdns.c udns.h
+dnsget: dnsget.o $(LIB)
+	$(CC) $(CFLAGS) -o $@ dnsget.o $(LIBFL)
+dnsget_s: dnsget.o $(SOLIB)
+	$(CC) $(CFLAGS) -o $@ dnsget.o $(SOLIBFL)
+rblcheck: rblcheck.o $(LIB)
+	$(CC) $(CFLAGS) -o $@ rblcheck.o $(LIBFL)
+rblcheck_s: rblcheck.o $(SOLIB)
+	$(CC) $(CFLAGS) -o $@ rblcheck.o $(SOLIBFL)
+ex-rdns: ex-rdns.o $(LIB)
+	$(CC) $(CFLAGS) -o $@ ex-rdns.o $(LIBFL)
+ex-rdns_s: ex-rdns.o $(SOLIB)
+	$(CC) $(CFLAGS) -o $@ ex-rdns.o $(SOLIBFL)

deps/udns/NEWS

@@ -0,0 +1,85 @@
+$Id: NEWS,v 1.11 2007/01/15 21:19:08 mjt Exp $
+
+User-visible changes in udns library.  Recent changes on top.
+
+0.0.9 (16 Jan 2007)
+
+ - incompat: minor API changes in dns_init() &friends.  dns_init()
+   now requires extra `struct dns_ctx *' argument.  Not bumped
+   soversion yet - I only expect one "release" with this change,
+   0.1 will have more changes and will increment so version
+
+ - many small bugfixes, here and there
+
+ - more robust FORMERR replies handling - not only such replies are now
+   recognized, but udns retries queries without EDNS0 extensions if tried
+   with, but server reported FORMERR
+
+ - portability changes, udns now includes getopt() implementation fo
+   the systems lacking it (mostly windows), and dns_ntop()&dns_pton(),
+   which are either just wrappers for system functions or reimplementations.
+
+ - build is now based on autoconf-like configuration
+
+ - NAPTR (RFC3403) RR decoding support
+
+ - new file NOTES which complements TODO somewhat, and includes some
+   important shortcomings
+
+ - many internal cleanups, including some preparations for better error
+   recovery, security and robustness (and thus API changes)
+
+ - removed some #defines which are now unused (like DNS_MAXSRCH)
+
+ - changed WIN32 to WINDOWS everywhere in preprocessor tests,
+   to be able to build it on win64 as well
+
+0.0.8 (12 Sep 2005)
+
+ - added SRV records (rfc2782) parsing,
+   thanks to Thadeu Lima de Souza Cascardo for implementation.
+
+ - bugfixes:
+   o use uninitialized value when no reply, library died with assertion:
+     assert((status < 0 && result == 0) || (status >= 0 && result != 0)).
+   o on some OSes, struct sockaddr_in has additional fields, so
+     memcmp'ing two sockaddresses does not work.
+
+ - rblcheck(.1)
+
+0.0.7 (20 Apr 2005)
+
+ - dnsget.1 manpage and several enhancements to dnsget.
+
+ - allow nameserver names for -n option of dnsget.
+
+ - API change: all dns_submit*() routines now does not expect
+   last `now' argument, since requests aren't sent immediately
+   anymore.
+
+ - API change: different application timer callback mechanism.
+   Udns now uses single per-context timer instead of per-query.
+
+ - don't assume DNS replies only contain backward DN pointers,
+   allow forward pointers too.  Change parsing API.
+
+ - debianize
+
+0.0.6 (08 Apr 2005)
+
+ - use double sorted list for requests (sorted by deadline).
+   This should significantly speed up timeout processing for
+   large number of requests.
+
+ - changed debugging interface, so it is finally useable
+   (still not documented).
+
+ - dnsget routine is now Officially Useable, and sometimes
+   even more useable than `host' from BIND distribution
+   (and sometimes not - dnsget does not have -C option
+   and TCP mode)
+
+ - Debian packaging in debian/ -- udns is now maintained as a
+   native Debian package.
+
+ - alot (and I really mean alot) of code cleanups all over.