ref: 3b6a42aaa1dfb75db06e9bf8cb7953cecefc647f
parent: 41046c6382017e0297f8e07a7493c2cd779b8f0b
author: Frank Smit <frank@61924.nl>
date: Fri Sep 18 13:21:29 EDT 2020
Query nameservers in parallel.
--- a/lib/std/resolve+posixy.myr
+++ b/lib/std/resolve+posixy.myr
@@ -22,8 +22,6 @@
use "types"
use "utf"
-use "fmt"
-
pkg std =
type rectype = union
`DnsA /* host address */
@@ -61,6 +59,8 @@
const resolve : (host : byte[:] -> result(hostinfo[:], resolveerr))
const resolvemx : (host : byte[:] -> result(hostinfo[:], resolveerr))
const resolverec : (host : byte[:], t : rectype[:] -> result(hostinfo[:], resolveerr))
+
+ const maxns = 5
;;
const Hostfile = "/etc/hosts"
@@ -152,7 +152,7 @@
invalid addresses are ignored: we don't want to break stuff
with invalid or unsupported addresses
*/
-
+
;;
| `None:
;;
@@ -222,7 +222,7 @@
match word(rest)
| `Some (name, _):
match ipparse(name)
- | `Some addr:
+ | `Some addr:
slpush(&nameservers, addr)
| `None:
/* nothing */
@@ -247,23 +247,32 @@
;;
}
-
const dnsresolve = {host, rt- var nsrv, r
+ var srv : sys.pollfd[maxns]
+ var cutoff
+ var ret
if !valid(host)
-> `Err (`Badhost)
;;
- /* FIXME: Assumption: nameservers is not modified by other threads */
- for ns : nameservers
- nsrv = dnsconnect(ns)
- if nsrv >= 0
- r = dnsquery(nsrv, host, rt)
- sys.close(nsrv)
- -> r
- ;;
+
+ cutoff = std.min(maxns, nameservers.len)
+
+ for var i = 0; i < cutoff; i++
+ srv[i] = [
+ .fd=dnsconnect(nameservers[i]),
+ .events=sys.Pollout,
+ .revents=0,
+ ]
;;
- -> `Err (`Badsrv)
+
+ ret = dnsquery(srv[:cutoff], host, rt)
+
+ for s : srv[:cutoff]
+ sys.close(s.fd)
+ ;;
+
+ -> ret
}
const dnsconnect = {ns@@ -295,10 +304,55 @@
}
const dnsquery = {srv, host, t- var id
+ var pkt : byte[512] /* big enough */
+ var id : uint16[maxns]
+ var query
+ var fail
+ var giveup
- id = tquery(srv, host, t)
- -> rquery(srv, host, id)
+ fail = 0
+ giveup = now() + 1000*Timeout
+
+ while true
+ /* all failed */
+ if fail == srv.len
+ break
+ ;;
+
+ var r = sys.poll(srv, (giveup - std.now() : int)/1000)
+ if r < 0
+ -> `Err `Badconn
+ elif r == 0
+ -> `Err `Timeout
+ ;;
+
+ for var i = 0; i < srv.len; i++
+ var s = &srv[i]
+
+ if (s.revents & sys.Pollout) != 0
+ (id[i], query) = mkquery(host, t)
+ sys.write(s.fd, query)
+ s.events = sys.Pollin
+ elif (s.revents & sys.Pollin) != 0
+ var n = sys.read(s.fd, pkt[:])
+ if n < 0
+ -> `Err `Badconn
+ ;;
+
+ var inf = hosts(pkt[:n], host, id[i])
+ match inf
+ | `std.Err `Badresp:
+ /* continue polling */
+ | _:
+ -> inf
+ ;;
+ else
+ fail++
+ ;;
+ ;;
+ ;;
+
+ -> `Err (`Badsrv)
}
const Qr : uint16 = 1 << 0
@@ -308,7 +362,7 @@
const Ra : uint16 = 1 << 8
var nextid : uint16 = 42
-const tquery = {srv, host, t+const mkquery = {host, tvar pkt : byte[512] /* big enough */
var off : size
@@ -327,39 +381,7 @@
off += pack16(pkt[:], off, (t : uint16)) /* qtype: a record */
off += pack16(pkt[:], off, 0x1) /* qclass: inet4 */
- sys.write(srv, pkt[:off])
- -> nextid
-}
-
-const rquery = {srv, host, id- var pktbuf : byte[1024]
- var pkt, pfd, giveup
- var r, n, inf
-
- giveup = std.now() + 1000*Timeout
-:again
- pfd = [
- [.fd=srv, .events=sys.Pollin, .revents=0]
- ][:]
- r = sys.poll(pfd[:], (giveup - std.now() : int)/1000)
- if r < 0
- -> `Err `Badconn
- elif r == 0
- -> `Err `Timeout
- else
- n = sys.read(srv, pktbuf[:])
- if n < 0
- -> `Err `Badconn
- ;;
- pkt = pktbuf[:n]
- inf = hosts(pkt, host, id)
- match inf
- | `std.Err `Badresp:
- goto again
- | _:
- -> inf
- ;;
- ;;
+ -> (nextid, pkt[:off])
}
const hosts = {pkt, host, id