ref: d916a4c3823f55227ffae35738c2497256e307b5
dir: /appl/cmd/ip/bootpd.b/
implement Bootpd;
#
# to do:
# DHCP
#
include "sys.m";
sys: Sys;
include "draw.m";
include "bufio.m";
bufio: Bufio;
Iobuf: import bufio;
include "attrdb.m";
attrdb: Attrdb;
Attr, Db, Dbentry, Tuples: import attrdb;
include "dial.m";
dial: Dial;
include "ip.m";
ip: IP;
IPaddr, Udphdr: import ip;
include "ipattr.m";
ipattr: IPattr;
include "ether.m";
ether: Ether;
include "arg.m";
Bootpd: module
{
init: fn(nil: ref Draw->Context, argv: list of string);
};
stderr: ref Sys->FD;
debug: int;
sniff: int;
verbose: int;
siaddr: IPaddr;
netmask: IPaddr;
myname: string;
progname := "bootpd";
net := "/net";
ndb: ref Db;
ndbfile := "/lib/ndb/local";
mtime := 0;
testing := 0;
Udphdrsize: con IP->Udphdrlen;
init(nil: ref Draw->Context, args: list of string)
{
sys = load Sys Sys->PATH;
stderr = sys->fildes(2);
bufio = load Bufio Bufio->PATH;
if(bufio == nil)
loadfail(Bufio->PATH);
attrdb = load Attrdb Attrdb->PATH;
if(attrdb == nil)
loadfail(Attrdb->PATH);
attrdb->init();
dial = load Dial Dial->PATH;
if(dial == nil)
loadfail(Dial->PATH);
ip = load IP IP->PATH;
if(ip == nil)
loadfail(IP->PATH);
ip->init();
ipattr = load IPattr IPattr->PATH;
if(ipattr == nil)
loadfail(IPattr->PATH);
ipattr->init(attrdb, ip);
ether = load Ether Ether->PATH;
if(ether == nil)
loadfail(Ether->PATH);
ether->init();
verbose = 1;
sniff = 0;
debug = 0;
arg := load Arg Arg->PATH;
if(arg == nil)
raise "fail: load Arg";
arg->init(args);
arg->setusage("bootpd [-dsqv] [-f file] [-x network]");
progname = arg->progname();
while((o := arg->opt()) != 0)
case o {
'd' => debug++;
's' => sniff = 1; debug = 255;
'q' => verbose = 0;
'v' => verbose = 1;
'x' => net = arg->earg();
'f' => ndbfile = arg->earg();
't' => testing = 1; debug = 1; verbose = 1;
* => arg->usage();
}
args = arg->argv();
if(args != nil)
arg->usage();
arg = nil;
sys->pctl(Sys->FORKFD|Sys->FORKNS, nil);
if(!sniff && (err := dbread()) != nil)
error(err);
myname = sysname();
if(myname == nil)
error("system name not set");
(siaddr, err) = csquery(myname);
if(err != nil)
error(sys->sprint("can't find IP address for %s: %s", myname, err));
if(debug)
sys->fprint(stderr, "bootpd: local IP address is %s\n", siaddr.text());
addr := net+"/udp!*!67";
if(testing)
addr = net+"/udp!*!499";
if(debug)
sys->fprint(stderr, "bootpd: announcing %s\n", addr);
c := dial->announce(addr);
if(c == nil)
error(sys->sprint("can't announce %s: %r", addr));
if(sys->fprint(c.cfd, "headers") < 0)
error(sys->sprint("can't set headers mode: %r"));
if(debug)
sys->fprint(stderr, "bootpd: opening %s/data\n", c.dir);
c.dfd = sys->open(c.dir+"/data", sys->ORDWR);
if(c.dfd == nil)
error(sys->sprint("can't open %s/data: %r", c.dir));
spawn server(c);
}
loadfail(s: string)
{
error(sys->sprint("can't load %s: %r", s));
}
error(s: string)
{
sys->fprint(stderr, "bootpd: %s\n", s);
raise "fail:error";
}
server(c: ref Sys->Connection)
{
buf := array[2048] of byte;
badread := 0;
for(;;) {
n := sys->read(c.dfd, buf, len buf);
if(n <0) {
if (badread++ > 10)
break;
continue;
}
badread = 0;
if(n < Udphdrsize) {
if(debug)
sys->fprint(stderr, "bootpd: short Udphdr: %d bytes\n", n);
continue;
}
hdr := Udphdr.unpack(buf, Udphdrsize);
if(debug)
sys->fprint(stderr, "bootpd: received request from udp!%s!%d\n", hdr.raddr.text(), hdr.rport);
if(n < Udphdrsize+300) {
if(debug)
sys->fprint(stderr, "bootpd: short request of %d bytes\n", n - Udphdrsize);
continue;
}
(bootp, err) := Bootp.unpack(buf[Udphdrsize:]);
if(err != nil) {
if(debug)
sys->fprint(stderr, "bootpd: can't unpack packet: %s\n", err);
continue;
}
if(debug >= 2)
sys->fprint(stderr, "bootpd: recvd {%s}\n", bootp.text());
if(sniff)
continue;
if(bootp.htype != 1 || bootp.hlen != 6) {
# if it isn't ether, we don't do it
if(debug)
sys->fprint(stderr, "bootpd: hardware type not ether; ignoring.\n");
continue;
}
if((err = dbread()) != nil) {
sys->fprint(stderr, "bootpd: getreply: dbread failed: %s\n", err);
continue;
}
rec := lookup(bootp);
if(rec == nil) {
# we can't answer this request
if(debug)
sys->fprint(stderr, "bootpd: cannot answer request.\n");
continue;
}
if(debug)
sys->fprint(stderr, "bootpd: found a matching entry: {%s}\n", rec.text());
mkreply(bootp, rec);
if(verbose)
sys->print("bootpd: %s -> %s %s\n", ether->text(rec.ha), rec.hostname, rec.ip.text());
if(debug)
sys->fprint(stderr, "bootpd: reply {%s}\n", bootp.text());
repl := bootp.pack();
if(!testing)
arpenter(rec.ip.text(), ether->text(rec.ha));
send(hdr, repl);
}
sys->fprint(stderr, "bootpd: %d read errors: %r\n", badread);
}
arpenter(ip, ha: string)
{
if(debug)
sys->fprint(stderr, "bootpd: arp: %s -> %s\n", ip, ha);
fd := sys->open(net+"/arp", Sys->OWRITE);
if(fd == nil) {
if(debug)
sys->fprint(stderr, "bootpd: arp open failed: %r\n");
return;
}
if(sys->fprint(fd, "add %s %s", ip, ha) < 0){
if(debug)
sys->fprint(stderr, "bootpd: error writing arp: %r\n");
}
}
sysname(): string
{
t := rf("/dev/sysname");
if(t != nil)
return t;
return rf("#e/sysname");
}
rf(name: string): string
{
fd := sys->open(name, Sys->OREAD);
buf := array[Sys->NAMEMAX] of byte;
n := sys->read(fd, buf, len buf);
if(n <= 0)
return nil;
return string buf[0:n];
}
csquery(name: string): (IPaddr, string)
{
siaddr = ip->noaddr;
# get a local IP address by translating our sysname with cs(8)
csfile := net+"/cs";
fd := sys->open(net+"/cs", Sys->ORDWR);
if(fd == nil)
return (ip->noaddr, sys->sprint("can't open %s/cs: %r", csfile));
if(sys->fprint(fd, "net!%s!0", name) < 0)
return (ip->noaddr, sys->sprint("can't translate net!%s!0: %r", name));
sys->seek(fd, big 0, 0);
a := array[1024] of byte;
n := sys->read(fd, a, len a);
if(n <= 0)
return (ip->noaddr, "no result from "+csfile);
reply := string a[0:n];
(l, addr):= sys->tokenize(reply, " ");
if(l != 2)
return (ip->noaddr, "bad cs reply format");
(l, addr) = sys->tokenize(hd tl addr, "!");
if(l < 2)
return (ip->noaddr, "bad cs reply format");
(ok, ipa) := IPaddr.parse(hd addr);
if(ok < 0 || !ipok(siaddr))
return (ip->noaddr, "can't parse address: "+hd addr);
return (ipa, nil);
}
Hostinfo: adt {
hostname: string;
ha: array of byte; # hardware addr
ip: IPaddr; # client IP addr
bootf: string; # boot file path
netmask: IPaddr; # subnet mask
ipgw: IPaddr; # gateway IP addr
fs: IPaddr; # file server IP addr
auth: IPaddr; # authentication server IP addr
text: fn(inf: self ref Hostinfo): string;
};
send(hdr: ref Udphdr, msg: array of byte)
{
replyaddr := net+"/udp!255.255.255.255!68"; # TO DO: gateway
if(testing)
replyaddr = sys->sprint("udp!%s!%d", hdr.raddr.text(), hdr.rport);
lport := "67";
if(testing)
lport = "499";
c := dial->dial(replyaddr, lport);
if(c == nil) {
sys->fprint(stderr, "bootpd: can't dial %s for reply: %r\n", replyaddr);
return;
}
n := sys->write(c.dfd, msg, len msg);
if(n != len msg)
sys->fprint(stderr, "bootpd: udp write error: %r\n");
}
mkreply(bootp: ref Bootp, rec: ref Hostinfo)
{
bootp.op = 2; # boot reply
bootp.yiaddr = rec.ip;
bootp.siaddr = siaddr;
bootp.giaddr = ip->noaddr;
bootp.sname = myname;
bootp.file = string rec.bootf;
bootp.vend = array of byte sys->sprint("p9 %s %s %s %s", rec.netmask.text(), rec.fs.text(), rec.auth.text(), rec.ipgw.text());
}
dbread(): string
{
if(ndb == nil){
ndb = Db.open(ndbfile);
if(ndb == nil)
return sys->sprint("cannot open %s: %r", ndbfile);
}else if(ndb.changed())
ndb.reopen();
return nil;
}
ipok(a: IPaddr): int
{
return a.isv4() && !(a.eq(ip->v4noaddr) || a.eq(ip->noaddr) || a.ismulticast());
}
lookup(bootp: ref Bootp): ref Hostinfo
{
if(ndb == nil)
return nil;
inf: ref Hostinfo;
hwaddr := ether->text(bootp.chaddr);
if(ipok(bootp.ciaddr)){
# client thinks it knows address; check match with MAC address
ipaddr := bootp.ciaddr.text();
ptr: ref Attrdb->Dbptr;
for(;;){
e: ref Dbentry;
(e, ptr) = ndb.findbyattr(ptr, "ip", ipaddr, "ether");
if(e == nil)
break;
# TO DO: check result
inf = matchandfill(e, "ip", ipaddr, "ether", hwaddr);
if(inf != nil)
return inf;
}
}
# look up an ip address associated with given MAC address
ptr: ref Attrdb->Dbptr;
for(;;){
e: ref Dbentry;
(e, ptr) = ndb.findbyattr(ptr, "ether", hwaddr, "ip");
if(e == nil)
break;
# TO DO: check right net etc.
inf = matchandfill(e, "ether", hwaddr, "ip", nil);
if(inf != nil)
return inf;
}
return nil;
}
matchandfill(e: ref Dbentry, attr: string, val: string, rattr: string, rval: string): ref Hostinfo
{
matches := e.findbyattr(attr, val, rattr);
for(; matches != nil; matches = tl matches){
(line, attrs) := hd matches;
for(; attrs != nil; attrs = tl attrs){
if(rval == nil || (hd attrs).val == rval){
inf := fillup(line, e);
if(inf != nil)
return inf;
break;
}
}
}
return nil;
}
fillup(line: ref Tuples, e: ref Dbentry): ref Hostinfo
{
ok: int;
inf := ref Hostinfo;
inf.netmask = ip->noaddr;
inf.ipgw = ip->noaddr;
inf.fs = ip->v4noaddr;
inf.auth = ip->v4noaddr;
inf.hostname = find(line, e, "sys");
s := find(line, e, "ether");
if(s != nil)
inf.ha = ether->parse(s);
s = find(line, e, "ip");
if(s == nil)
return nil;
(ok, inf.ip) = IPaddr.parse(s);
if(ok < 0)
return nil;
(results, err) := ipattr->findnetattrs(ndb, "ip", s, list of{"ipmask", "ipgw", "fs", "FILESERVER", "SIGNER", "auth", "bootf"});
if(err != nil)
return nil;
for(; results != nil; results = tl results){
(a, nattrs) := hd results;
if(!a.eq(inf.ip))
continue; # different network
for(; nattrs != nil; nattrs = tl nattrs){
na := hd nattrs;
case na.name {
"ipmask" =>
inf.netmask = takeipmask(na.pairs, inf.netmask);
"ipgw" =>
inf.ipgw = takeipattr(na.pairs, inf.ipgw);
"fs" or "FILESERVER" =>
inf.fs = takeipattr(na.pairs, inf.fs);
"auth" or "SIGNER" =>
inf.auth = takeipattr(na.pairs, inf.auth);
"bootf" =>
inf.bootf = takeattr(na.pairs, inf.bootf);
}
}
}
return inf;
}
takeattr(pairs: list of ref Attr, s: string): string
{
if(s != nil || pairs == nil)
return s;
return (hd pairs).val;
}
takeipattr(pairs: list of ref Attr, a: IPaddr): IPaddr
{
if(pairs == nil || !(a.eq(ip->noaddr) || a.eq(ip->v4noaddr)))
return a;
(ok, na) := parseip((hd pairs).val);
if(ok < 0)
return a;
return na;
}
takeipmask(pairs: list of ref Attr, a: IPaddr): IPaddr
{
if(pairs == nil || !(a.eq(ip->noaddr) || a.eq(ip->v4noaddr)))
return a;
(ok, na) := IPaddr.parsemask((hd pairs).val);
if(ok < 0)
return a;
return na;
}
findip(line: ref Tuples, e: ref Dbentry, attr: string): (int, IPaddr)
{
s := find(line, e, attr);
if(s == nil)
return (-1, ip->noaddr);
return parseip(s);
}
parseip(s: string): (int, IPaddr)
{
(ok, a) := IPaddr.parse(s);
if(ok < 0){
# look it up if it's a system name
s = findbyattr("sys", s, "ip");
(ok, a) = IPaddr.parse(s);
}
return (ok, a);
}
find(line: ref Tuples, e: ref Dbentry, attr: string): string
{
if(line != nil){
a := line.find(attr);
if(a != nil)
return (hd a).val;
}
if(e != nil){
for(matches := e.find(attr); matches != nil; matches = tl matches){
(nil, a) := hd matches;
if(a != nil)
return (hd a).val;
}
}
return nil;
}
findbyattr(attr: string, val: string, rattr: string): string
{
ptr: ref Attrdb->Dbptr;
for(;;){
e: ref Dbentry;
(e, ptr) = ndb.findbyattr(ptr, attr, val, rattr);
if(e == nil)
break;
rvl := e.find(rattr);
if(rvl != nil){
(nil, al) := hd rvl;
return (hd al).val;
}
}
return nil;
}
missing(rec: ref Hostinfo): string
{
s := "";
if(rec.ha == nil)
s += " hardware address";
if(rec.ip.eq(ip->noaddr))
s += " IP address";
if(rec.bootf == nil)
s += " bootfile";
if(rec.netmask.eq(ip->noaddr))
s += " subnet mask";
if(rec.ipgw.eq(ip->noaddr))
s += " gateway";
if(rec.fs.eq(ip->noaddr))
s += " file server";
if(rec.auth.eq(ip->noaddr))
s += " authentication server";
if(s != "")
return s[1:];
return nil;
}
dtoa(data: array of byte): string
{
if(data == nil)
return nil;
result: string;
for(i:=0; i < len data; i++)
result += sys->sprint(".%d", int data[i]);
return result[1:];
}
magic(cookie: array of byte): string
{
if(eqa(cookie, array[] of { byte 'p', byte '9', byte ' ', byte ' ' }))
return "plan9";
if(eqa(cookie, array[] of { byte 99, byte 130, byte 83, byte 99 }))
return "rfc1048";
if(eqa(cookie, array[] of { byte 'C', byte 'M', byte 'U', byte 0 }))
return "cmu";
return dtoa(cookie);
}
eqa(a1: array of byte, a2: array of byte): int
{
if(len a1 != len a2)
return 0;
for(i := 0; i < len a1; i++)
if(a1[i] != a2[i])
return 0;
return 1;
}
Hostinfo.text(rec: self ref Hostinfo): string
{
return sys->sprint("ha=%s ip=%s bf=%s sm=%s gw=%s fs=%s au=%s",
ether->text(rec.ha), rec.ip.text(), rec.bootf, rec.netmask.masktext(), rec.ipgw.text(), rec.fs.text(), rec.auth.text());
}
Bootp: adt
{
op: int; # opcode [1]
htype: int; # hardware type[1]
hlen: int; # hardware address length [1]
hops: int; # gateway hops [1]
xid: int; # random number [4]
secs: int; # seconds elapsed since client started booting [2]
flags: int; # flags[2]
ciaddr: IPaddr; # client ip address (client->server)[4]
yiaddr: IPaddr; # your ip address (server->client)[4]
siaddr: IPaddr; # server's ip address [4]
giaddr: IPaddr; # gateway ip address [4]
chaddr: array of byte; # client hardware (mac) address [16]
sname: string; # server host name [64]
file: string; # boot file name [128]
vend: array of byte; # vendor-specific [128]
unpack: fn(a: array of byte): (ref Bootp, string);
pack: fn(bp: self ref Bootp): array of byte;
text: fn(bp: self ref Bootp): string;
};
Bootp.unpack(data: array of byte): (ref Bootp, string)
{
if(len data < 300)
return (nil, "too short");
bp := ref Bootp;
bp.op = int data[0];
bp.htype = int data[1];
bp.hlen = int data[2];
if(bp.hlen > 16)
return (nil, "length error");
bp.hops = int data[3];
bp.xid = ip->get4(data, 4);
bp.secs = ip->get2(data, 8);
bp.flags = ip->get2(data, 10);
bp.ciaddr = IPaddr.newv4(data[12:16]);
bp.yiaddr = IPaddr.newv4(data[16:20]);
bp.siaddr = IPaddr.newv4(data[20:24]);
bp.giaddr = IPaddr.newv4(data[24:28]);
bp.chaddr = data[28:28+bp.hlen];
bp.sname = ctostr(data[44:108]);
bp.file = ctostr(data[108:236]);
bp.vend = data[236:300];
return (bp, nil);
}
Bootp.pack(bp: self ref Bootp): array of byte
{
data := array[364] of { * => byte 0 };
data[0] = byte bp.op;
data[1] = byte bp.htype;
data[2] = byte bp.hlen;
data[3] = byte bp.hops;
ip->put4(data, 4, bp.xid);
ip->put2(data, 8, bp.secs);
ip->put2(data, 10, bp.flags);
data[12:] = bp.ciaddr.v4();
data[16:] = bp.yiaddr.v4();
data[20:] = bp.siaddr.v4();
data[24:] = bp.giaddr.v4();
data[28:] = bp.chaddr;
data[44:] = array of byte bp.sname;
data[108:] = array of byte bp.file;
data[236:] = bp.vend;
return data;
}
ctostr(cstr: array of byte): string
{
for(i:=0; i<len cstr; i++)
if(cstr[i] == byte 0)
break;
return string cstr[0:i];
}
Bootp.text(bp: self ref Bootp): string
{
s := sys->sprint("op=%d htype=%d hlen=%d hops=%d xid=%ud secs=%ud ciaddr=%s yiaddr=%s",
int bp.op, bp.htype, bp.hlen, bp.hops, bp.xid, bp.secs, bp.ciaddr.text(), bp.yiaddr.text());
s += sys->sprint(" server=%s gateway=%s hwaddr=%q host=%q file=%q magic=%q",
bp.siaddr.text(), bp.giaddr.text(), ether->text(bp.chaddr), bp.sname, bp.file, magic(bp.vend[0:4]));
if(magic(bp.vend[0:4]) == "plan9")
s += "("+ctostr(bp.vend)+")";
return s;
}