/* Generate a peer id : "-TRxyzb-" + 12 random alphanumeric
characters, where x is the major version number, y is the
minor version number, z is the maintenance number, and b
designates beta (Azureus-style) */
uint8_t*
tr_peerIdNew( void )
{
int i;
int val;
int total = 0;
uint8_t * buf = tr_new( uint8_t, 21 );
const char * pool = "0123456789abcdefghijklmnopqrstuvwxyz";
const int base = 36;
memcpy( buf, PEERID_PREFIX, 8 );
for( i = 8; i < 19; ++i )
{
val = tr_cryptoRandInt( base );
total += val;
buf[i] = pool[val];
}
val = total % base ? base - ( total % base ) : 0;
buf[19] = pool[val];
buf[20] = '\0';
return buf;
}
static int
readYa( tr_handshake * handshake,
struct evbuffer * inbuf )
{
uint8_t ya[KEY_LEN];
uint8_t * walk, outbuf[KEY_LEN + PadB_MAXLEN];
const uint8_t *myKey, *secret;
int len;
dbgmsg( handshake, "in readYa... need %d, have %zu",
KEY_LEN, evbuffer_get_length( inbuf ) );
if( evbuffer_get_length( inbuf ) < KEY_LEN )
return READ_LATER;
/* read the incoming peer's public key */
evbuffer_remove( inbuf, ya, KEY_LEN );
secret = tr_cryptoComputeSecret( handshake->crypto, ya );
memcpy( handshake->mySecret, secret, KEY_LEN );
tr_sha1( handshake->myReq1, "req1", 4, secret, KEY_LEN, NULL );
dbgmsg( handshake, "sending B->A: Diffie Hellman Yb, PadB" );
/* send our public key to the peer */
walk = outbuf;
myKey = tr_cryptoGetMyPublicKey( handshake->crypto, &len );
memcpy( walk, myKey, len );
walk += len;
len = tr_cryptoRandInt( PadB_MAXLEN );
tr_cryptoRandBuf( walk, len );
walk += len;
setReadState( handshake, AWAITING_PAD_A );
tr_peerIoWriteBytes( handshake->io, outbuf, walk - outbuf, FALSE );
return READ_NOW;
}
static int
test_cryptoRand( void )
{
int i;
/* test that tr_cryptoRandInt() stays in-bounds */
for( i = 0; i < 100000; ++i )
{
const int val = tr_cryptoRandInt( 100 );
check( val >= 0 );
check( val < 100 );
}
return 0;
}
/* 1 A->B: Diffie Hellman Ya, PadA */
static void
sendYa( tr_handshake * handshake )
{
int len;
const uint8_t * public_key;
char outbuf[ KEY_LEN + PadA_MAXLEN ], *walk=outbuf;
/* add our public key (Ya) */
public_key = tr_cryptoGetMyPublicKey( handshake->crypto, &len );
assert( len == KEY_LEN );
assert( public_key );
memcpy( walk, public_key, len );
walk += len;
/* add some bullshit padding */
len = tr_cryptoRandInt( PadA_MAXLEN );
tr_cryptoRandBuf( walk, len );
walk += len;
/* send it */
setReadState( handshake, AWAITING_YB );
tr_peerIoWriteBytes( handshake->io, outbuf, walk - outbuf, FALSE );
}