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Oops! We actually want the *lower* 6 bits of the crc32 of the multicast

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address to generate the multicast filter bit index, not the upper 6.

Should address kern/8268.
This commit is contained in:
thorpej 2000-05-12 16:57:30 +00:00
parent 6e4b4f6954
commit f0481f14ab
1 changed files with 6 additions and 9 deletions
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15
sys/dev/ic/smc83c170.c
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@ -1,4 +1,4 @@
/* $NetBSD: smc83c170.c,v 1.30 2000/05/12 16:45:43 thorpej Exp $ */ /* $NetBSD: smc83c170.c,v 1.31 2000/05/12 16:57:30 thorpej Exp $ */
/*- /*-
* Copyright (c) 1998, 1999 The NetBSD Foundation, Inc. * Copyright (c) 1998, 1999 The NetBSD Foundation, Inc.
@ -1319,14 +1319,14 @@ epic_set_mchash(sc)
struct ifnet *ifp = &sc->sc_ethercom.ec_if; struct ifnet *ifp = &sc->sc_ethercom.ec_if;
struct ether_multi *enm; struct ether_multi *enm;
struct ether_multistep step; struct ether_multistep step;
u_int32_t crc, mchash[4]; u_int32_t hash, mchash[4];
/* /*
* Set up the multicast address filter by passing all multicast * Set up the multicast address filter by passing all multicast
* addresses through a CRC generator, and then using the high-order * addresses through a CRC generator, and then using the low-order
* 6 bits as an index into the 64 bit multicast hash table (only * 6 bits as an index into the 64 bit multicast hash table (only
* the lower 16 bits of each 32 bit multicast hash register are * the lower 16 bits of each 32 bit multicast hash register are
* valid). The high order bit selects the register, while the * valid). The high order bits select the register, while the
* rest of the bits select the bit within the register. * rest of the bits select the bit within the register.
*/ */
@ -1354,13 +1354,10 @@ epic_set_mchash(sc)
goto allmulti; goto allmulti;
} }
crc = ether_crc32_le(enm->enm_addrlo, ETHER_ADDR_LEN); hash = ether_crc32_le(enm->enm_addrlo, ETHER_ADDR_LEN) & 0x3f;
/* Just want the 6 most significant bits. */
crc >>= 26;
/* Set the corresponding bit in the hash table. */ /* Set the corresponding bit in the hash table. */
mchash[crc >> 4] |= 1 << (crc & 0xf); mchash[hash >> 4] |= 1 << (hash & 0xf);
ETHER_NEXT_MULTI(step, enm); ETHER_NEXT_MULTI(step, enm);
} }