ref: f0f00c4644ec29bc528c2b47e9ec4e284f72cccc
parent: ff204601124da81b70dfa97f3072eee8eebb99bb
author: Ori Bernstein <[email protected]>
date: Tue Oct 29 07:50:11 EDT 2013
Add start of DNS resolver.
Broken, but at least it compiles.
--- a/libstd/Makefile
+++ b/libstd/Makefile
@@ -16,6 +16,7 @@
option.myr \
optparse.myr \
rand.myr \
+ resolve.myr \
slappend.myr \
slcp.myr \
sldup.myr \
--- /dev/null
+++ b/libstd/resolve.myr
@@ -1,0 +1,102 @@
+use "alloc.use"
+use "endian.use"
+use "error.use"
+use "fmt.use"
+use "sys.use"
+use "types.use"
+
+pkg std =
+ type resolveerr = union
+ `Badhost
+ `Badsrv
+ `Badquery
+ ;;
+
+ type hostinfo = struct
+ flags : uint32
+ fam : sockfam
+ stype : socktype
+ proto : uint32
+ addr : sockaddr[:]
+ canon : byte[:]
+ next : hostinfo#
+ ;;
+
+ const resolve : (host : byte[:] -> hostinfo#)
+;;
+
+const resolve = {host : byte[:]+ var hinf
+
+ hinf = zalloc()
+ dnsresolve(host)
+ -> hinf
+}
+
+const dnsresolve = {host : byte[:]+ /*var hosts*/
+ var nsrv
+
+ if !valid(host)
+ -> `Failure (`Badhost)
+ ;;
+ if (nsrv = dnsconnect()) < 0
+ -> `Failure (`Badsrv)
+ ;;
+ if !dnsquery(nsrv, host)
+ -> `Failure (`Badquery)
+ ;;
+ -> `Success true
+}
+
+const dnsconnect = {+ var sa : sockaddr_in
+ var s
+ var status
+
+ s = socket(Afinet, Sockstream, 0)
+ if s < 0
+ put("Warning: Failed to open socket: %l\n", s)+ -> -1
+ ;;
+ /* hardcode Google DNS for now */
+ sa.port = hosttonet(53)
+ sa.addr = 0x08080808
+ status = connect(s, (&sa) castto(sockaddr#), sizeof(sockaddr_in))
+ if status < 0
+ put("Warning: Failed to connect to server: %l\n", s)+ -> -1
+ ;;
+ -> s
+}
+
+const dnsquery = {srv, host+ put("Unimplemented query: srv=%z, host=%s\n", srv, host)+ -> false
+}
+
+const valid = {host : byte[:]+ var i
+ var seglen
+
+ /* maximum length: 255 chars */
+ if host.len > 255
+ -> false
+ ;;
+
+ seglen = 0
+ for i = 0; i < host.len; i++
+ if host[i] == ('.' castto(byte))+ seglen = 0
+ ;;
+ if seglen > 63
+ -> false
+ ;;
+ if host[i] & 0x80
+ -> false
+ ;;
+ ;;
+
+ -> true
+
+}