auc3g: officially wrap IND around IND_bitlen space
To determine distinct IND pools for each connected VLR, we need to pick ever increasing values for any new peer showing up. Each subscriber's individual IND_bitlen is then required to modulo the least significant N of bits that fit in its IND_bitlen to effectively round-robin in the available IND pool space. So far we did that but issued a warning message. This is actually exactly what we want and it doesn't need to be treated like it weren't so. Change-Id: I716d8a8a249235c8093d7a6a78b3535d893d867e
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src/db_auc.c
17
src/db_auc.c
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@ -200,15 +200,16 @@ int db_get_auc(struct db_context *dbc, const char *imsi,
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if (rc)
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return rc;
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/* modulo by the IND bitlen value range. For example, ind_bitlen == 5 would modulo 32:
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* 1 << 5 == 0b0100000 == 32
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* - 1 == 0b0011111 == bitmask of 5 lowest bits
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* x &= 0b0011111 == modulo 32
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* Why do this? osmo-hlr cannot possibly choose individual VLR INDs always matching all subscribers' IND_bitlen,
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* which might vary wildly. Instead, let hlr.c pass in an arbitrarily high number here, and the modulo does a
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* round-robin if the IND pools that this subscriber has available. */
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auc_3g_ind &= (1U << aud3g.u.umts.ind_bitlen) - 1;
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aud3g.u.umts.ind = auc_3g_ind;
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if (aud3g.type == OSMO_AUTH_TYPE_UMTS
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&& aud3g.u.umts.ind >= (1U << aud3g.u.umts.ind_bitlen)) {
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LOGAUC(imsi, LOGL_NOTICE, "3G auth: SQN's IND bitlen %u is"
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" too small to hold an index of %u. Truncating. This"
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" may cause numerous additional AUTS resyncing.\n",
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aud3g.u.umts.ind_bitlen, aud3g.u.umts.ind);
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aud3g.u.umts.ind &= (1U << aud3g.u.umts.ind_bitlen) - 1;
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}
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/* the first bit (bit0) cannot be used as AMF anymore, but has been
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* re-appropriated as the separation bit. See 3GPP TS 33.102 Annex H
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* together with 3GPP TS 33.401 / 33.402 / 33.501 */
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