[9fans] Small patch to tftpd; command line announce strings.

[9fans] Small patch to tftpd; command line announce strings.

[Dan Cross]

My new setup (which is still not on the Internet just yet, and probably
won't be for a few weeks at this point) is a little...weird.  I have
two interfaces bound to a single IP stack, one exposed to the net, one
not.  For a variety of reasons, this is more convenient than using
multiple stacks (in particular, I want to run services on both
interfaces, and listen doesn't seem to have a ``-x'' option, I don't
want to start everything twice, and I want to try and play some routing
tricks later where the internal interface will also answer requests
[from internal clients] for the external interface).  I'm running a
DHCP and tftpd server for internal clients, but I don't want any fool
with a tftp client to start downloading kernels from me.  DHCP I don't
care about since ip/dhcpd only answers for clients it knows about by
default, and the immediate subnet is pretty trustworthy.  The upshot
of all this is that I modified tftpd to add a ``-A'' option which takes
an announce string, so one can specify an interface to announce on.
E.g., ``ip/tftpd -A 'udp!192.168.1.4!69' '' sort of thing.  A diff in
diff -e format is below.  Are there any objections for adding this to
the distribution?

	- Dan C.

term% diff -e /n/sources/plan9/sys/src/cmd/ip/tftpd.c tftpd.c
102c
	sprint(buf, "%s/%s", net, a);
.
60a
	case 'A':
		a = ARGF();
		break;
.
58a
	a = "udp!*!69";
.
57c
	char *p, *a;
.
term% 

Re: [9fans] Small patch to tftpd; command line announce strings.

[geoff]

Listen doesn't need a -x; its last argument is the network directory
to use:

	aux/listen -t /bin/service.auth -d /bin/service.alt /net.alt/tcp

Initialising additional interfaces isn't conveniently packaged up, so
I wrote `ifup', which does the job.  I use it like this in cpurc:

# network services
aux/listen -q -t /bin/service.auth -d /bin/service tcp
ip/tftpd
ip/dhcpd
# alternate interfaces & their services
switch ($sysname) {
case cpu
	ifup alt 1 $sysname	external service.alt
	ifup gig 2 $sysname-gig	local	 service
	timesync /net.alt/udp!^((ntp1 ntp2)^.mainecoon.com openbsd)
case cpub
	ifup alt 1 $sysname external service.alt
case cpuc
	ifup gig 1 $sysname-gig local service
}

The first interface (/net) is handled specially; it often is already
configured when cpurc starts.

This is ifup:
---
#!/bin/rc
# ifup mtsfx etherno sysnm ndbfile svcdir - configure /net.$mtsfx
# TODO: share a protocol stack between ether0 and gig ether
#	and just add a route to the other gig host
if (! ~ $#* 5) {
	echo usage: $0 mtsfx etherno sysnm ndbfile svcdir
	exit usage
}
rfork e
mtsfx=$1	etherno=$2	sysnm=$3	ndbfile=$4	svcdir=$5
mtpt=/net.^$mtsfx
ndbf=/lib/ndb/^$ndbfile

# merge protocol stack and ethernet interface at mount point
bind -b '#l'^$etherno $mtpt
bind -b '#I'^$etherno $mtpt

# figure out ip, ipgw & ipmask
ipgw=dummy			# in case ndb doesn't list one
for (attr in ip ipgw ipmask)
	eval `{ndb/ipquery -f $ndbf sys $sysnm $attr | tr ' ' '\12' | sed 1q}

# configure interface and set up out-calling machinery
# first arg can be "ether" or "gbe" iff it can handle jumbo packets
ip/ipconfig -x .$mtsfx -g $ipgw ether $mtpt/ether$etherno $ip $ipmask
ndb/cs -x $mtpt -f $ndbf
if (! ~ $mtsfx gig)
 	ndb/dns -sx $mtpt -f $ndbf

# start up listeners
aux/listen -t /bin/service.auth -d /bin/^$svcdir $mtpt^/tcp
if (! ~ $mtsfx gig) {
	ip/dhcpd -x $mtpt -f $ndbf	# for the printer
	ip/rip -x $mtpt
}
if (~ $mtsfx alt)
	auth/secstored -x $mtpt
---