/*
* Mausezahn - A fast versatile traffic generator
* Copyright (C) 2008-2010 Herbert Haas
*
* This program is free software; you can redistribute it and/or modify it under
* the terms of the GNU General Public License version 2 as published by the
* Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
* details.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, see http://www.gnu.org/licenses/gpl-2.0.html
*
*/
#include "mz.h"
#include "mops.h"
// Assigns MPLS tag at position i (starting at zero!) with values:
//
// m ... total number of tags (important to set BoS in last tag)
// Label ... label value
// Exp ... EXP field (typically CoS)
// TTL ... Time To Live
//
// NOTE: Two usage possibilities!
//
// 1.) When called from for-loop to add all tags the total size mpls_s
// is updated continuously and the BoS is set in the last tag.
// Therefore set m = total number of tags!
//
// 2.) But when changing a particular tag within an existing MPLS stack
// the total number of tags does not change, therefore use m=0.
//
// RETURN VALUE: 0 upon success, 1 upon failure
//
int mops_mpls(struct mops *mp, int i, int m, u_int32_t Label, u_int8_t Exp, u_int8_t TTL)
{
u_int8_t *ptr;
if ((m) && (i>=m)) return 1; // label index greater than number of labels!
if (Label > 1048575) return 1;
if (Exp > 7) return 1;
// Create binary tag: Label(20) EXP(3) BoS(1) TTL(8)
Label <<= 4;
ptr = (u_int8_t *) &Label;
mp->mpls[4*i+0] = *(ptr+2);
mp->mpls[4*i+1] = *(ptr+1);
mp->mpls[4*i+2] = *(ptr+0);
Exp <<= 1;
mp->mpls[4*i+2] |= Exp;
mp->mpls[4*i+3] = TTL;
if ((m) && (i==(m-1))) // reached last tag!
{
mp->mpls[4*i+2] |= 0x01; // set BoS in last tag
mp->mpls_s =4*m;
mp->use_MPLS = 1;
if ( (mp->eth_type != 0x8847) && (mp->eth_type != 0x8848) )
{
mp->eth_type_backup = mp->eth_type;
}
mp->eth_type = 0x8847;
}
return 0;
}
// Remove MPLS tags from packet mp
//
// j indicates which tag to be removed (1..n)
// j=0 means: remove all tags!
//
// RETURN VALUE: 1 upon failure, 0 upon success
int mops_mpls_remove (struct mops *mp, int j)
{
int a, b, k;
if (j==0) // remove all tags
{
if (mp->use_MPLS)
{
mp->mpls_s=0;
mp->use_MPLS=0;
mp->eth_type = mp->eth_type_backup; // restore original ethertype
return 0;
}
else
return 1;
}
k = mp->mpls_s/4;
if (j>k) return 1; // The packet only consists of k tag(s)
if (k==1) // only delete the single tag
{
mp->mpls_s=0;
mp->use_MPLS=0;
mp->eth_type = mp->eth_type_backup; // restore original ethertype
return 0;
}
// if we got here we have more than one tag:
if (j==k) // remove last tag (of several)
{
mp->mpls_s -=4;
return 0;
}
// remove some non-ending tag: 0, 1, 2, 3
a = (j-1)*4; // target
b = j*4; // source (what should be copied)
memcpy(&mp->mpls[a], &mp->mpls[b], (k-j)*4);
mp->mpls_s -=4;
return 0;
}
// Set BOS in tag k where k=1..n
int mops_mpls_bos (struct mops *mp, int k)
{
int n;
n = mp->mpls_s/4; // n = total number of tags
if (k>n) return 1;
mp->mpls[(k-1)*4+2] |= 0x01;
return 0;
}
// Unset BOS in tag k where k=1..n
int mops_mpls_nobos (struct mops *mp, int k)
{
int n;
n = mp->mpls_s/4; // n = total number of tags
if (k>n) return 1;
mp->mpls[(k-1)*4+2] &= 0xfe;
return 0;
}
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