ref: d916a4c3823f55227ffae35738c2497256e307b5
dir: /appl/cmd/ip/ppp/modem.b/
implement Modem;
include "sys.m";
sys: Sys;
include "lock.m";
lock: Lock;
Semaphore: import lock;
include "draw.m";
include "modem.m";
hangupcmd := "ATH0"; # was ATZH0 but some modem versions on Umec hung on ATZ (BUG: should be in modeminfo)
# modem return codes
Ok, Success, Failure, Abort, Noise, Found: con iota;
maxspeed: con 115200;
#
# modem return messages
#
Msg: adt {
text: string;
code: int;
};
msgs: array of Msg = array [] of {
("OK", Ok),
("NO CARRIER", Failure),
("ERROR", Failure),
("NO DIALTONE", Failure),
("BUSY", Failure),
("NO ANSWER", Failure),
("CONNECT", Success),
};
kill(pid: int)
{
fd := sys->open("#p/"+string pid+"/ctl", Sys->OWRITE);
if(fd == nil || sys->fprint(fd, "kill") < 0)
sys->print("modem: can't kill %d: %r\n", pid);
}
#
# prepare a modem port
#
openserial(d: ref Device)
{
if (d==nil) {
raise "fail: device not initialized";
return;
}
d.data = nil;
d.ctl = nil;
d.data = sys->open(d.local, Sys->ORDWR);
if(d.data == nil) {
raise "fail: can't open "+d.local;
return;
}
d.ctl = sys->open(d.local+"ctl", Sys->ORDWR);
if(d.ctl == nil) {
raise "can't open "+d.local+"ctl";
return;
}
d.speed = maxspeed;
d.avail = nil;
}
#
# shut down the monitor (if any) and return the connection
#
close(m: ref Device): ref Sys->Connection
{
if(m == nil)
return nil;
if(m.pid != 0){
kill(m.pid);
m.pid = 0;
}
if(m.data == nil)
return nil;
mc := ref sys->Connection(m.data, m.ctl, nil);
m.ctl = nil;
m.data = nil;
return mc;
}
#
# Send a string to the modem
#
send(d: ref Device, x: string): int
{
if (d == nil)
return -1;
a := array of byte x;
f := sys->write(d.data, a, len a);
if (f < 0) {
# let's attempt to close & reopen the modem
close(d);
openserial(d);
f = sys->write(d.data,a, len a);
}
sys->print("->%s\n",x);
return f;
}
#
# apply a string of commands to modem & look for a response
#
apply(d: ref Device, s: string, substr: string, secs: int): int
{
m := Ok;
buf := "";
for(i := 0; i < len s; i++){
c := s[i];
buf[len buf] = c; # assume no Unicode
if(c == '\r' || i == (len s -1)){
if(c != '\r')
buf[len buf] = '\r';
if(send(d, buf) < 0)
return Abort;
(m, nil) = readmsg(d, secs, substr);
buf = "";
}
}
return m;
}
#
# get modem into command mode if it isn't already
#
GUARDTIME: con 1100; # usual default for S12=50 in units of 1/50 sec; allow 100ms fuzz
attention(d: ref Device): int
{
for(i := 0; i < 3; i++){
if(apply(d, hangupcmd, nil, 2) == Ok)
return Ok;
sys->sleep(GUARDTIME);
if(send(d, "+++") < 0)
return Abort;
sys->sleep(GUARDTIME);
(nil, msg) := readmsg(d, 0, nil);
if(msg != nil)
sys->print("status: %s\n", msg);
}
return Failure;
}
#
# apply a command type
#
applyspecial(d: ref Device, cmd: string): int
{
if(cmd == nil)
return Failure;
return apply(d, cmd, nil, 2);
}
#
# hang up any connections in progress and close the device
#
onhook(d: ref Device)
{
if(d == nil)
return;
# hang up the modem
monitoring(d);
if(attention(d) != Ok)
sys->print("modem: no attention\n");
# hangup the stream (eg, for ppp) and toggle the lines to the modem
if(d.ctl != nil) {
sys->fprint(d.ctl,"d0\n");
sys->fprint(d.ctl,"r0\n");
sys->fprint(d.ctl, "h\n"); # hangup on native serial
sys->sleep(250);
sys->fprint(d.ctl,"r1\n");
sys->fprint(d.ctl,"d1\n");
}
close(d);
}
#
# does string s contain t anywhere?
#
contains(s, t: string): int
{
if(t == nil)
return 1;
if(s == nil)
return 0;
n := len t;
for(i := 0; i+n <= len s; i++)
if(s[i:i+n] == t)
return 1;
return 0;
}
#
# read till we see a message or we time out
#
readmsg(d: ref Device, secs: int, substr: string): (int, string)
{
if (d == nil)
return (Abort, "device not initialized");
found := 0;
secs *= 1000;
limit := 1000; # pretty arbitrary
s := "";
for(start := sys->millisec(); sys->millisec() <= start+secs;){
a := getinput(d,1);
if(len a == 0){
if(limit){
sys->sleep(1);
continue;
}
break;
}
if(a[0] == byte '\n' || a[0] == byte '\r' || limit == 0){
if (len s) {
if (s[(len s)-1] == '\r')
s[(len s)-1] = '\n';
sys->print("<-%s\n",s);
}
if(substr != nil && contains(s, substr))
found = 1;
for(k := 0; k < len msgs; k++)
if(len s >= len msgs[k].text &&
s[0:len msgs[k].text] == msgs[k].text){
if(found)
return (Found, s);
return (msgs[k].code, s);
}
start = sys->millisec();
s = "";
continue;
}
s[len s] = int a[0];
limit--;
}
s = "No response from modem";
if(found)
return (Found, s);
return (Noise, s);
}
#
# get baud rate from a connect message
#
getspeed(msg: string, speed: int): int
{
p := msg[7:]; # skip "CONNECT"
while(p[0] == ' ' || p[0] == '\t')
p = p[1:];
s := int p;
if(s <= 0)
return speed;
else
return s;
}
#
# set speed and RTS/CTS modem flow control
#
setspeed(d: ref Device, baud: int)
{
if(d != nil && d.ctl != nil){
sys->fprint(d.ctl, "b%d", baud);
sys->fprint(d.ctl, "m1");
}
}
dumpa(a: array of byte): string
{
s := "";
for(i:=0; i<len a; i++){
b := int a[i];
if(b >= ' ' && b < 16r7f)
s[len s] = b;
else
s += sys->sprint("\\%.2x", b);
}
return s;
}
monitoring(d: ref Device)
{
# if no monitor then spawn one
if(d.pid == 0) {
pidc := chan of int;
spawn monitor(d, pidc);
d.pid = <-pidc;
}
}
#
# a process to read input from a modem.
#
monitor(d: ref Device, pidc: chan of int)
{
openserial(d);
pidc <-= sys->pctl(0, nil); # pidc can be written once only.
a := array[Sys->ATOMICIO] of byte;
for(;;) {
d.lock.obtain();
d.status = "Idle";
d.remote = "";
setspeed(d, d.speed);
d.lock.release();
# shuttle bytes
while((n := sys->read(d.data, a, len a)) > 0){
d.lock.obtain();
if (len d.avail < Sys->ATOMICIO) {
na := array[len d.avail + n] of byte;
na[0:] = d.avail[0:];
na[len d.avail:] = a[0:n];
d.avail = na;
}
d.lock.release();
}
# on an error, try reopening the device
d.data = nil;
d.ctl = nil;
openserial(d);
}
}
#
# return up to n bytes read from the modem by monitor()
#
getinput(d: ref Device, n: int): array of byte
{
if(d==nil || n <= 0)
return nil;
a: array of byte;
d.lock.obtain();
if(len d.avail != 0){
if(n > len d.avail)
n = len d.avail;
a = d.avail[0:n];
d.avail = d.avail[n:];
}
d.lock.release();
return a;
}
getc(m: ref Device, timo: int): int
{
start := sys->millisec();
while((b := getinput(m, 1)) == nil) {
if (timo && sys->millisec() > start+timo)
return 0;
sys->sleep(1);
}
return int b[0];
}
init(modeminfo: ref ModemInfo): ref Device
{
if (sys == nil) {
sys = load Sys Sys->PATH;
lock = load Lock Lock->PATH;
if (lock == nil) {
raise "fail: Couldn't load lock module";
return nil;
}
lock->init();
}
newdev := ref Device;
newdev.lock = Semaphore.new();
newdev.local = modeminfo.path;
newdev.pid = 0;
newdev.t = modeminfo;
return newdev;
}
#
# dial a number
#
dial(d: ref Device, number: string)
{
if (d==nil) {
raise "fail: Device not initialized";
return;
}
monitoring(d);
# modem type should already be established, but just in case
sys->print("Attention\n");
x := attention(d);
if (x != Ok)
sys->print("Attention failed\n");
#
# extended Hayes commands, meaning depends on modem (VGA all over again)
#
sys->print("Init\n");
if(d.t.country != nil)
applyspecial(d, d.t.country);
if(d.t.init != nil)
applyspecial(d, d.t.init);
if(d.t.other != nil)
applyspecial(d, d.t.other);
applyspecial(d, d.t.errorcorrection);
compress := Abort;
if(d.t.mnponly != nil)
compress = applyspecial(d, d.t.mnponly);
if(d.t.compression != nil)
compress = applyspecial(d, d.t.compression);
rateadjust := Abort;
if(compress != Ok)
rateadjust = applyspecial(d, d.t.rateadjust);
applyspecial(d, d.t.flowctl);
# finally, dialout
sys->print("Dialing\n");
if((dt := d.t.dialtype) == nil)
dt = "ATDT";
if(send(d, sys->sprint("%s%s\r", dt, number)) < 0) {
raise "can't dial "+number;
return;
}
(i, msg) := readmsg(d, 120, nil);
if(i != Success) {
raise "fail: "+msg;
return;
}
connectspeed := getspeed(msg, d.speed);
# change line rate if not compressing
if(rateadjust == Ok)
setspeed(d, connectspeed);
if(d.ctl != nil){
if(d != nil)
sys->fprint(d.ctl, "s%d", connectspeed); # set DCE speed (if device implements it)
sys->fprint(d.ctl, "c1"); # enable CD monitoring
}
}