Mercurial > dropbear
view libtommath/bn_mp_sub.c @ 296:6b41e2cbf071 dbclient-netcat-alike
A hack to make dbclient to tcp forwarding netcat style.
eg
./dbclient -i testkey -L 1234:remotehost:remoteport tunnelhost
will ssh to tunnelhost (using testkey, there's no way to ask for a password)
and then tcpfwd to remotehost:remoteport on stdin/stdout.
There's no way to give a cmdline password, so -i for a keyfile will have to do.
Yet another reason for agent forwarding.
The 1234 is a dummy var, I think it has to be a valid portnumber though.
author | Matt Johnston <matt@ucc.asn.au> |
---|---|
date | Tue, 21 Mar 2006 16:16:41 +0000 |
parents | eed26cff980b |
children | 5ff8218bcee9 |
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#include <tommath.h> #ifdef BN_MP_SUB_C /* LibTomMath, multiple-precision integer library -- Tom St Denis * * LibTomMath is a library that provides multiple-precision * integer arithmetic as well as number theoretic functionality. * * The library was designed directly after the MPI library by * Michael Fromberger but has been written from scratch with * additional optimizations in place. * * The library is free for all purposes without any express * guarantee it works. * * Tom St Denis, [email protected], http://math.libtomcrypt.org */ /* high level subtraction (handles signs) */ int mp_sub (mp_int * a, mp_int * b, mp_int * c) { int sa, sb, res; sa = a->sign; sb = b->sign; if (sa != sb) { /* subtract a negative from a positive, OR */ /* subtract a positive from a negative. */ /* In either case, ADD their magnitudes, */ /* and use the sign of the first number. */ c->sign = sa; res = s_mp_add (a, b, c); } else { /* subtract a positive from a positive, OR */ /* subtract a negative from a negative. */ /* First, take the difference between their */ /* magnitudes, then... */ if (mp_cmp_mag (a, b) != MP_LT) { /* Copy the sign from the first */ c->sign = sa; /* The first has a larger or equal magnitude */ res = s_mp_sub (a, b, c); } else { /* The result has the *opposite* sign from */ /* the first number. */ c->sign = (sa == MP_ZPOS) ? MP_NEG : MP_ZPOS; /* The second has a larger magnitude */ res = s_mp_sub (b, a, c); } } return res; } #endif