Subversion Repositories planix.SVN

#include "os.h"
#include <libsec.h>

/* rfc2104 */
DigestState*
hmac_x(uchar *p, ulong len, uchar *key, ulong klen, uchar *digest, DigestState *s,
        DigestState*(*x)(uchar*, ulong, uchar*, DigestState*), int xlen)
{
        int i;
        uchar pad[Hmacblksz+1], innerdigest[256];

        if(xlen > sizeof(innerdigest))
                return nil;
        if(klen > Hmacblksz){
                if(xlen > Hmacblksz)
                        return nil;
                (*x)(key, klen, innerdigest, nil);
                key = innerdigest;
                klen = xlen;
        }

        /* first time through */
        if(s == nil || s->seeded == 0){
                memset(pad, 0x36, Hmacblksz);
                pad[Hmacblksz] = 0;
                for(i = 0; i < klen; i++)
                        pad[i] ^= key[i];
                s = (*x)(pad, Hmacblksz, nil, s);
                if(s == nil)
                        return nil;
        }

        s = (*x)(p, len, nil, s);
        if(digest == nil)
                return s;

        /* last time through */
        memset(pad, 0x5c, Hmacblksz);
        pad[Hmacblksz] = 0;
        for(i = 0; i < klen; i++)
                pad[i] ^= key[i];
        (*x)(nil, 0, innerdigest, s);
        s = (*x)(pad, Hmacblksz, nil, nil);
        (*x)(innerdigest, xlen, digest, s);
        return nil;
}