From: "Russ Cox" <rsc@plan9.bell-labs.com>
To: 9fans@cse.psu.edu
Subject: Re: [9fans] fs error msg: didn't like (1460 274) byte message
Date: Tue, 24 Sep 2002 19:42:24 -0400 [thread overview]
Message-ID: <b725e9c5d41e55c4280f3e5db5bb3bd3@plan9.bell-labs.com> (raw)
Oops. I wonder why we never noticed that before.
The problem is that TCP lost the race, and a 1734 byte
message got turned into a 1460 and a 2764. Since IL
preserves message delimiters, the file server choked
on the two halves. Here's a new aux/trampoline. Run
aux/trampoline -9 and it should do the right thing
as far as putting the 9P messages back together before
passing them along.
Let me know if it works, and I'll put it on sources.
Russ
#include <u.h>
#include <libc.h>
#include <bio.h>
#include <ndb.h>
#include <fcall.h>
enum
{
Maxpath= 128,
};
typedef struct Endpoints Endpoints;
struct Endpoints
{
char *net;
char *lsys;
char *lserv;
char *rsys;
char *rserv;
};
void xfer(int, int);
void xfer9p(int, int);
Endpoints* getendpoints(char*);
void freeendpoints(Endpoints*);
char* iptomac(char*, char*);
int macok(char*);
void
main(int argc, char **argv)
{
int fd;
int checkmac = 0;
Endpoints *ep;
char *mac;
void (*x)(int, int);
x = xfer;
ARGBEGIN{
case 'm':
checkmac = 1;
break;
case '9':
x = xfer9p;
break;
}ARGEND;
if(argc < 1){
fprint(2, "usage: %s dialstring\n", argv0);
exits("usage");
}
if(checkmac && argc > 1){
ep = getendpoints(argv[1]);
mac = iptomac(ep->rsys, ep->net);
if(!macok(mac)){
syslog(0, "trampoline", "badmac %s from %s!%s for %s!%s on %s",
mac, ep->rsys, ep->rserv, ep->lsys, ep->lserv, ep->net);
exits("bad mac");
}
}
fd = dial(argv[0], 0, 0, 0);
if(fd < 0){
fprint(2, "%s: dialing %s: %r\n", argv0, argv[0]);
exits("dial");
}
rfork(RFNOTEG);
switch(fork()){
case -1:
fprint(2, "%s: fork: %r\n", argv0);
exits("dial");
case 0:
(*x)(0, fd);
break;
default:
(*x)(fd, 1);
break;
}
postnote(PNGROUP, getpid(), "die yankee pig dog");
exits(0);
}
void
xfer(int from, int to)
{
char buf[12*1024];
int n;
while((n = read(from, buf, sizeof buf)) > 0)
if(write(to, buf, n) < 0)
break;
}
void
xfer9p(int from, int to)
{
char *buf;
uint nbuf;
int n;
nbuf = 256;
buf = malloc(nbuf);
if(buf == nil)
sysfatal("xfer: malloc %ud: %r", nbuf);
for(;;){
if(readn(from, buf, 4) != 4)
break;
n = GBIT32(buf);
if(4+n > nbuf){
nbuf = 4+n+8192;
buf = realloc(buf, nbuf);
if(buf == nil)
sysfatal("xfer: realloc %ud: %r", nbuf);
}
if(readn(from, buf+4, n) != n)
break;
if(write(to, buf, 4+n) != 4+n)
break;
}
}
void
getendpoint(char *dir, char *file, char **sysp, char **servp)
{
int fd, n;
char buf[Maxpath];
char *sys, *serv;
sys = serv = 0;
snprint(buf, sizeof buf, "%s/%s", dir, file);
fd = open(buf, OREAD);
if(fd >= 0){
n = read(fd, buf, sizeof(buf)-1);
if(n>0){
buf[n-1] = 0;
serv = strchr(buf, '!');
if(serv){
*serv++ = 0;
serv = strdup(serv);
}
sys = strdup(buf);
}
close(fd);
}
if(serv == 0)
serv = strdup("unknown");
if(sys == 0)
sys = strdup("unknown");
*servp = serv;
*sysp = sys;
}
Endpoints *
getendpoints(char *dir)
{
Endpoints *ep;
char *p;
ep = malloc(sizeof(*ep));
ep->net = strdup(dir);
p = strchr(ep->net+1, '/');
if(p == nil){
free(ep->net);
ep->net = "/net";
} else
*p = 0;
getendpoint(dir, "local", &ep->lsys, &ep->lserv);
getendpoint(dir, "remote", &ep->rsys, &ep->rserv);
return ep;
}
void
freeendpoints(Endpoints *ep)
{
free(ep->lsys);
free(ep->rsys);
free(ep->lserv);
free(ep->rserv);
free(ep);
}
char*
iptomac(char *ip, char *net)
{
char file[Maxpath];
Biobuf *b;
char *p;
char *f[5];
snprint(file, sizeof(file), "%s/arp", net);
b = Bopen(file, OREAD);
if(b == nil)
return nil;
while((p = Brdline(b, '\n')) != nil){
p[Blinelen(b)-1] = 0;
if(tokenize(p, f, nelem(f)) < 4)
continue;
if(strcmp(f[1], "OK") == 0
&& strcmp(f[2], ip) == 0){
p = strdup(f[3]);
Bterm(b);
return p;
}
}
Bterm(b);
return nil;
}
int
macok(char *mac)
{
Ndbtuple *tp;
char buf[Ndbvlen];
if(mac == nil)
return 0;
tp = csgetval("/net", "ether", mac, "trampok", buf);
if(tp == nil)
return 0;
ndbfree(tp);
return 1;
}
next reply other threads:[~2002-09-24 23:42 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-09-24 23:42 Russ Cox [this message]
2002-09-25 11:45 ` Axel Belinfante
2002-09-25 18:19 ` Axel Belinfante
-- strict thread matches above, loose matches on Subject: below --
2002-09-25 21:30 Russ Cox
2002-09-26 8:49 ` Axel Belinfante
2002-09-25 21:21 Russ Cox
2002-09-25 18:24 Russ Cox
2002-09-25 18:44 ` Axel Belinfante
2002-09-25 21:12 ` Axel Belinfante
2002-09-24 23:25 Axel Belinfante
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