The next API function is the AddrMulticastRemove() function used to remove an (IP-to-Ethernet) multicast hardware address from a device.
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Every device driver’s net_dev.c
Prototype
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static void NetDev_AddrMulticastRemove (NET_IF *p_if,
CPU_INT08U *p_addr_hw,
CPU_INT08U addr_hw_len,
NET_ERR *p_err); |
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Required Configuration
Necessary only if if NET_MCAST_CFG_IPv4_RX_EN or NET_IPMCAST_CFG_MULTICAST_SELIPv4_TX_EN is configured for transmit and receive multicasting (see NET_IP_CFG_MULTICAST_SEL).
Notes / Warnings
Use same exact code as in NetDev_AddrMulticastAdd() to calculate the device’s CRC hash (see NetDev_MgmtDemux()), but remove a multicast address by decrementing the device’s hash bit reference counters and clearing the appropriate bits in the device’s multicast registers.
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/* ---------- CALCULATE HASH CODE ---------- */
/* Use NetDev_AddrMulticastAdd()'s algorithm to calculate CRC hash. */
/* - REMOVE MULTICAST ADDRESS FROM DEVICE -- */
paddr_hash_ctrs = &pdev_data->MulticastAddrHashBitCtr[hash];
if (*paddr_hash_ctrs > 1u) { /* If multiple multicast addresses hashed, ..*/
(*paddr_hash_ctrs)--; /* .. decrement hash bit reference counter ..*/
*perr = NET_DEV_ERR_NONE; /* .. but do NOT unconfigure hash register. */
return;
}
*paddr_hash_ctrs = 0u; /* Clear hash bit reference counter. */
if (hash <= 31u) { /* Clear multicast hash register bit. */
pdev->MCAST_REG_LO &= ~(1u << reg_bit); /* (Substitute 'MCAST_REG_LO/HI' with .. */
} else { /* .. device's actual multicast registers.) */
pdev->MCAST_REG_HI &= ~(1u << reg_bit);
} |
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