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ip/torrent: avoid requesting same chunks

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instead of always just requesting the missing range
of the current piece, remember the workpiece offset
and request sequential chunks from the workpiece.

this avoids double requests of the same ranges when
the peer does not respond with the data immidiately.
This commit is contained in:
cinap_lenrek 2017-05-01 00:01:14 +02:00
parent c00c60d327
commit 2713779ee6
1 changed files with 26 additions and 21 deletions
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47
sys/src/cmd/ip/torrent.c
View file

@ -55,7 +55,7 @@ int port = 6881;
char *deftrack = "http://exodus.desync.com/announce";
char *mntweb = "/mnt/web";
char *useragent = "torrent";
uchar infohash[20];
uchar infohash[SHA1dlen];
uchar peerid[20];
int blocksize;
@ -212,9 +212,9 @@ rwpiece(int wr, int index, uchar *data, int len, int poff)
}
int
havepiece(int x)
havepiece(int x, char *from)
{
uchar *p, m, hash[20];
uchar *p, m, hash[SHA1dlen];
int n;
m = 0x80>>(x&7);
@ -228,8 +228,11 @@ havepiece(int x)
}
sha1(p, n, hash, nil);
free(p);
if(memcmp(hash, pieces[x].hash, 20))
if(memcmp(hash, pieces[x].hash, sizeof(hash))){
if(debug && from != nil)
fprint(2, "peer %s: damaged piece %d\n", from, x);
return 0;
}
lock(&stats);
if((havemap[x>>3] & m) == 0){
havemap[x>>3] |= m;
@ -237,6 +240,8 @@ havepiece(int x)
stats.left -= pieces[x].len;
}
unlock(&stats);
if(debug && from != nil)
fprint(2, "peer %s: completed piece %d\n", from, x);
return 1;
}
@ -382,7 +387,7 @@ peer(int fd, int incoming, char *addr)
uchar buf[64+MAXIO], *map, *told, *p, m;
int mechoking, hechoking;
int mewant, hewant;
int workpiece;
int workpiece, workoffset;
int i, o, l, x, n;
if(debug) fprint(2, "peer %s: %s connected\n", addr, incoming ? "incoming" : "outgoing");
@ -419,6 +424,8 @@ peer(int fd, int incoming, char *addr)
mewant = 0;
hewant = 0;
workpiece = -1;
workoffset = 0;
map = mallocz(nhavemap, 1);
told = malloc(nhavemap);
@ -451,18 +458,15 @@ peer(int fd, int incoming, char *addr)
}
if(!hechoking && mewant){
x = workpiece;
if(x < 0 || (havemap[x>>3]&(0x80>>(x&7))) != 0)
if(x < 0 || (havemap[x>>3]&(0x80>>(x&7))) != 0 || workoffset >= pieces[x].len)
x = pickpiece(map);
if(x >= 0){
workpiece = x;
o = pieces[x].brk;
if(o < 0 || o >= pieces[x].len){
pieces[x].brk = 0;
o = 0;
}
o = workpiece != x ? pieces[x].brk : workoffset;
l = pieces[x].len - o;
if(l > MAXIO)
l = MAXIO;
workpiece = x;
workoffset = o + l;
if(debug) fprint(2, "peer %s: -> request %d %d %d\n", addr, x, o, l);
n = pack(buf, sizeof(buf), "lblll", 1+4+4+4, 0x06, x, o, l);
if(write(fd, buf, n) != n)
@ -566,7 +570,8 @@ peer(int fd, int incoming, char *addr)
if(n <= 0)
continue;
pieces[x].brk = o+n;
if(o+n >= pieces[x].len && !havepiece(x)){
if(o+n >= pieces[x].len && !havepiece(x, addr)){
pieces[x].brk = 0;
/* backoff from this piece for a while */
if(x == workpiece)
workpiece = -1;
@ -797,7 +802,7 @@ Error:
o += m;
n -= m;
p = 0;
if(havepiece(x++))
if(havepiece(x++, w->str))
continue;
if(++err > 10){
close(fd);
@ -806,8 +811,8 @@ Error:
}
}
}
havepiece(off / blocksize);
havepiece(f->off / blocksize);
havepiece(off / blocksize, w->str);
havepiece(f->off / blocksize, w->str);
close(fd);
exits(0);
}
@ -1033,7 +1038,7 @@ Hfmt(Fmt *f)
int
mktorrent(int fd, Dict *alist, Dict *wlist)
{
uchar *b, h[20];
uchar *b, h[SHA1dlen];
Dir *d;
int n;
@ -1321,14 +1326,14 @@ main(int argc, char *argv[])
if((blocksize = atoi(s)) <= 0)
sysfatal("bogus piece length in meta info");
d = dlook(info, "pieces");
if(d == nil || d->typ != 's' || d->len <= 0 || d->len % 20)
if(d == nil || d->typ != 's' || d->len <= 0 || d->len % SHA1dlen)
sysfatal("bad or no pices in meta info");
npieces = d->len / 20;
npieces = d->len / SHA1dlen;
pieces = mallocz(sizeof(Piece) * npieces, 1);
nhavemap = (npieces+7) / 8;
havemap = mallocz(nhavemap, 1);
for(i = 0; i<npieces; i++){
pieces[i].hash = (uchar*)d->str + i*20;
pieces[i].hash = (uchar*)d->str + i*SHA1dlen;
if(len < blocksize)
pieces[i].len = len;
else
@ -1345,7 +1350,7 @@ main(int argc, char *argv[])
sysfatal("fork: %r");
case 0:
for(; i<npieces; i+=nproc)
havepiece(i);
havepiece(i, nil);
exits(0);
}
}