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#include <u.h>
#include <libc.h>
#include <fcall.h>
enum {
Hdrsz = 3*4,
Bufsize = 8*1024,
};
typedef struct Hdr Hdr;
typedef struct Buf Buf;
typedef struct Client Client;
struct Hdr {
uchar nb[4]; // Number of data bytes in this message
uchar msg[4]; // Message number
uchar acked[4]; // Number of messages acked
};
struct Buf {
Hdr hdr;
uchar buf[Bufsize];
Buf *next;
};
struct Client {
QLock lk;
char *addr;
int netfd;
int pipefd;
int timeout;
int reader;
int writer;
int syncer;
ulong inmsg;
ulong outmsg;
Buf *unackedhead;
Buf **unackedtail;
};
static void
reconnect(Client *c)
{
Buf *b;
int n;
ulong to;
qlock(&c->lk);
to = (ulong)time(0) + c->timeout;
Again:
for(;;){
if(c->netfd >= 0){
close(c->netfd);
c->netfd = -1;
}
if((c->netfd = dial(c->addr,nil,nil,nil)) >= 0)
break;
if((ulong)time(0) >= to)
sysfatal("dial timed out: %r");
sleep(1000);
}
for(b = c->unackedhead; b != nil; b = b->next){
n = GBIT32(b->hdr.nb);
PBIT32(b->hdr.acked, c->inmsg);
if(write(c->netfd, &b->hdr, Hdrsz) != Hdrsz
|| write(c->netfd, b->buf, n) != n){
print("write error: %r\n");
goto Again;
}
}
qunlock(&c->lk);
}
static void
aanwriter(void *arg)
{
Client *c = (Client*)arg;
Buf *b;
int n;
ulong m;
for(;;){
b = malloc(sizeof(Buf));
if(b == nil)
break;
if((n = read(c->pipefd, b->buf, Bufsize)) < 0){
free(b);
break;
}
qlock(&c->lk);
m = c->outmsg++;
PBIT32(b->hdr.nb, n);
PBIT32(b->hdr.msg, m);
PBIT32(b->hdr.acked, c->inmsg);
b->next = nil;
if(c->unackedhead == nil)
c->unackedtail = &c->unackedhead;
*c->unackedtail = b;
c->unackedtail = &b->next;
if(c->netfd < 0
|| write(c->netfd, &b->hdr, Hdrsz) != Hdrsz
|| write(c->netfd, b->buf, n) != n){
qunlock(&c->lk);
continue;
}
qunlock(&c->lk);
if(n == 0)
break;
}
close(c->pipefd);
c->pipefd = -1;
}
static void
aansyncer(void *arg)
{
Client *c = (Client*)arg;
Hdr hdr;
for(;;){
sleep(4000);
qlock(&c->lk);
if(c->netfd >= 0){
PBIT32(hdr.nb, 0);
PBIT32(hdr.acked, c->inmsg);
PBIT32(hdr.msg, -1);
write(c->netfd, &hdr, Hdrsz);
}
qunlock(&c->lk);
}
}
static void
aanreader(void *arg)
{
Client *c = (Client*)arg;
ulong a, m, lastacked = 0;
Buf *b, *x;
int n;
Restart:
b = mallocz(sizeof(Buf), 1);
for(;;){
if(readn(c->netfd, &b->hdr, Hdrsz) != Hdrsz)
break;
a = GBIT32(b->hdr.acked);
m = GBIT32(b->hdr.msg);
n = GBIT32(b->hdr.nb);
if(n == 0){
if(m == (ulong)-1)
continue;
goto Closed;
} else if(n < 0 || n > Bufsize)
goto Closed;
if(readn(c->netfd, b->buf, n) != n)
break;
if(m != c->inmsg)
continue;
c->inmsg++;
if((long)(a - lastacked) > 0){
qlock(&c->lk);
while((x = c->unackedhead) != nil){
assert(GBIT32(x->hdr.msg) == lastacked);
c->unackedhead = x->next;
free(x);
if(++lastacked == a)
break;
}
qunlock(&c->lk);
}
if(c->pipefd < 0)
goto Closed;
write(c->pipefd, b->buf, n);
}
free(b);
reconnect(c);
goto Restart;
Closed:
free(b);
if(c->pipefd >= 0)
write(c->pipefd, "", 0);
}
int
aanclient(char *addr, int timeout)
{
Client *c;
int pfd[2];
if(pipe(pfd) < 0)
sysfatal("pipe: %r");
c = mallocz(sizeof(Client), 1);
c->addr = addr;
c->netfd = -1;
c->pipefd = pfd[1];
c->inmsg = 0;
c->outmsg = 0;
c->timeout = 60;
reconnect(c);
c->timeout = timeout;
c->writer = kproc("aanwriter", aanwriter, c);
c->reader = kproc("aanreader", aanreader, c);
c->syncer = kproc("aansyncer", aansyncer, c);
return pfd[0];
}
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