ref: dc593372bfc4224c6cf91d2031d0ad0aeadaddfe
dir: /sys/src/cmd/aan.c/
#include <u.h>
#include <libc.h>
#include <auth.h>
#include <fcall.h>
#include <thread.h>
#define NS(x) ((vlong)x)
#define US(x) (NS(x) * 1000LL)
#define MS(x) (US(x) * 1000LL)
#define S(x) (MS(x) * 1000LL)
enum {
Synctime = S(8),
Nbuf = 10,
K = 1024,
Bufsize = 8 * K,
Stacksize = 8 * K,
Timer = 0, // Alt channels.
Unsent = 1,
Maxto = 24 * 3600, // A full day to reconnect.
Hdrsz = 3*4,
};
typedef struct {
uchar nb[4]; // Number of data bytes in this message
uchar msg[4]; // Message number
uchar acked[4]; // Number of messages acked
} Hdr;
typedef struct {
Hdr hdr;
uchar buf[Bufsize];
} Buf;
static Channel *unsent;
static Channel *unacked;
static Channel *empty;
static int netfd;
static ulong inmsg;
static ulong outmsg;
static char *devdir;
static int debug;
static int done;
static char *dialstring;
static int maxto = Maxto;
static char *Logname = "aan";
static int client;
static int reader = -1;
static int lostsync;
static Alt a[] = {
/* c v op */
{ nil, nil, CHANRCV }, // timer
{ nil, nil, CHANRCV }, // unsent
{ nil, nil, CHANEND },
};
static void fromnet(void*);
static void fromclient(void*);
static int reconnect(int);
static void synchronize(void);
static int writen(int, uchar *, int);
static void timerproc(void *);
static void
usage(void)
{
fprint(2, "usage: %s [-cd] [-m maxto] dialstring|netdir\n", argv0);
exits("usage");
}
static int
catch(void *, char *s)
{
if (!strcmp(s, "alarm")) {
syslog(0, Logname, "Timed out while waiting for reconnect, exiting...");
threadexitsall(nil);
}
return 0;
}
static void*
emalloc(int n)
{
uintptr pc;
void *v;
pc = getcallerpc(&n);
v = malloc(n);
if(v == nil)
sysfatal("Cannot allocate memory; pc=%#p", pc);
setmalloctag(v, pc);
return v;
}
void
threadmain(int argc, char **argv)
{
vlong synctime;
int i, n, failed;
Channel *timer;
Hdr hdr;
Buf *b;
ARGBEGIN {
case 'c':
client++;
break;
case 'd':
debug++;
break;
case 'm':
maxto = (int)strtol(EARGF(usage()), nil, 0);
break;
default:
usage();
} ARGEND;
if (argc != 1)
usage();
if (!client) {
char *p;
devdir = argv[0];
if ((p = strstr(devdir, "/local")) != nil)
*p = '\0';
}
else
dialstring = argv[0];
if (debug > 0) {
int fd = open("#c/cons", OWRITE|OCEXEC);
dup(fd, 2);
}
atnotify(catch, 1);
/*
* Set up initial connection. use short timeout
* of 60 seconds so we wont hang arround for too
* long if there is some general connection problem
* (like NAT).
*/
netfd = reconnect(60);
unsent = chancreate(sizeof(Buf *), Nbuf);
unacked = chancreate(sizeof(Buf *), Nbuf);
empty = chancreate(sizeof(Buf *), Nbuf);
timer = chancreate(sizeof(uchar *), 1);
if(unsent == nil || unacked == nil || empty == nil || timer == nil)
sysfatal("Cannot allocate channels");
for (i = 0; i < Nbuf; i++)
sendp(empty, emalloc(sizeof(Buf)));
reader = proccreate(fromnet, nil, Stacksize);
if (reader < 0)
sysfatal("Cannot start fromnet; %r");
if (proccreate(fromclient, nil, Stacksize) < 0)
sysfatal("Cannot start fromclient; %r");
if (proccreate(timerproc, timer, Stacksize) < 0)
sysfatal("Cannot start timerproc; %r");
a[Timer].c = timer;
a[Unsent].c = unsent;
a[Unsent].v = &b;
Restart:
synctime = nsec() + Synctime;
failed = 0;
lostsync = 0;
while (!done) {
if (netfd < 0 || failed) {
// Wait for the netreader to die.
while (netfd >= 0) {
if(debug) fprint(2, "main; waiting for netreader to die\n");
threadint(reader);
sleep(1000);
}
// the reader died; reestablish the world.
netfd = reconnect(maxto);
synchronize();
goto Restart;
}
switch (alt(a)) {
case Timer:
if (netfd < 0 || nsec() < synctime)
break;
PBIT32(hdr.nb, 0);
PBIT32(hdr.acked, inmsg);
PBIT32(hdr.msg, -1);
if (writen(netfd, (uchar *)&hdr, Hdrsz) < 0) {
failed = 1;
continue;
}
if(++lostsync > 2){
syslog(0, Logname, "connection seems hung up...");
failed = 1;
continue;
}
synctime = nsec() + Synctime;
break;
case Unsent:
sendp(unacked, b);
if (netfd < 0)
break;
PBIT32(b->hdr.acked, inmsg);
if (writen(netfd, (uchar *)&b->hdr, Hdrsz) < 0)
failed = 1;
else {
n = GBIT32(b->hdr.nb);
if (writen(netfd, b->buf, n) < 0)
failed = 1;
if (n == 0)
done = 1;
}
break;
}
}
syslog(0, Logname, "exiting...");
threadexitsall(nil);
}
static void
fromclient(void*)
{
int n;
Buf *b;
threadsetname("fromclient");
do {
b = recvp(empty);
n = read(0, b->buf, Bufsize);
if (n < 0)
n = 0;
PBIT32(b->hdr.nb, n);
PBIT32(b->hdr.msg, outmsg);
sendp(unsent, b);
outmsg++;
} while(n > 0);
}
static void
fromnet(void*)
{
extern void _threadnote(void *, char *);
ulong m, acked, lastacked = 0;
int n, len;
Buf *b;
notify(_threadnote);
threadsetname("fromnet");
b = emalloc(sizeof(Buf));
while (!done) {
while (netfd < 0) {
if(done)
return;
if(debug) fprint(2, "fromnet; waiting for connection... (inmsg %lud)\n", inmsg);
sleep(1000);
}
// Read the header.
len = readn(netfd, (uchar *)&b->hdr, Hdrsz);
if (len <= 0) {
if (debug) {
if (len < 0)
fprint(2, "fromnet; (hdr) network failure; %r\n");
else
fprint(2, "fromnet; (hdr) network closed\n");
}
close(netfd);
netfd = -1;
continue;
}
lostsync = 0; // reset timeout
n = GBIT32(b->hdr.nb);
m = GBIT32(b->hdr.msg);
acked = GBIT32(b->hdr.acked);
if (n == 0) {
if (m == (ulong)-1)
continue;
if(debug) fprint(2, "fromnet; network closed\n");
break;
} else if (n < 0 || n > Bufsize) {
if(debug) fprint(2, "fromnet; message too big %d > %d\n", n, Bufsize);
break;
}
len = readn(netfd, b->buf, n);
if (len <= 0 || len != n) {
if (len == 0)
if(debug) fprint(2, "fromnet; network closed\n");
else
if(debug) fprint(2, "fromnet; network failure; %r\n");
close(netfd);
netfd = -1;
continue;
}
if (m != inmsg) {
if(debug) fprint(2, "fromnet; skipping message %lud, currently at %lud\n", m, inmsg);
continue;
}
inmsg++;
// Process the acked list.
while((long)(acked - lastacked) > 0) {
Buf *rb;
if((rb = recvp(unacked)) == nil)
break;
m = GBIT32(rb->hdr.msg);
if (m != lastacked) {
if(debug) fprint(2, "fromnet; rb %p, msg %lud, lastacked %lud\n", rb, m, lastacked);
sysfatal("fromnet; bug");
}
PBIT32(rb->hdr.msg, -1);
sendp(empty, rb);
lastacked++;
}
if (writen(1, b->buf, len) < 0)
sysfatal("fromnet; cannot write to client; %r");
}
done = 1;
}
static int
reconnect(int secs)
{
NetConnInfo *nci;
char ldir[40];
int lcfd, fd;
if (dialstring) {
syslog(0, Logname, "dialing %s", dialstring);
alarm(secs*1000);
while ((fd = dial(dialstring, nil, ldir, nil)) < 0) {
char err[32];
err[0] = '\0';
errstr(err, sizeof err);
if (strstr(err, "connection refused")) {
if(debug) fprint(2, "reconnect; server died...\n");
threadexitsall("server died...");
}
if(debug) fprint(2, "reconnect: dialed %s; %s\n", dialstring, err);
sleep(1000);
}
alarm(0);
syslog(0, Logname, "reconnected to %s", dialstring);
}
else {
syslog(0, Logname, "waiting for connection on %s", devdir);
alarm(secs*1000);
if ((lcfd = listen(devdir, ldir)) < 0)
sysfatal("reconnect; cannot listen; %r");
if ((fd = accept(lcfd, ldir)) < 0)
sysfatal("reconnect; cannot accept; %r");
alarm(0);
close(lcfd);
}
if(nci = getnetconninfo(ldir, fd)){
syslog(0, Logname, "connected from %s", nci->rsys);
threadsetname(client? "client %s %s" : "server %s %s", ldir, nci->rsys);
freenetconninfo(nci);
} else
syslog(0, Logname, "connected");
return fd;
}
static void
synchronize(void)
{
Channel *tmp;
Buf *b;
int n;
// Ignore network errors here. If we fail during
// synchronization, the next alarm will pick up
// the error.
tmp = chancreate(sizeof(Buf *), Nbuf);
while ((b = nbrecvp(unacked)) != nil) {
n = GBIT32(b->hdr.nb);
writen(netfd, (uchar *)&b->hdr, Hdrsz);
writen(netfd, b->buf, n);
sendp(tmp, b);
}
chanfree(unacked);
unacked = tmp;
}
static int
writen(int fd, uchar *buf, int nb)
{
int len = nb;
while (nb > 0) {
int n;
if (fd < 0)
return -1;
if ((n = write(fd, buf, nb)) < 0) {
if(debug) fprint(2, "writen; Write failed; %r\n");
return -1;
}
buf += n;
nb -= n;
}
return len;
}
static void
timerproc(void *x)
{
Channel *timer = x;
threadsetname("timer");
while (!done) {
sleep((Synctime / MS(1)) >> 1);
sendp(timer, "timer");
}
}