Re: [PATCH] iscsi_ibft: Print correct IPv6 netmask

Christoph Hellwig
2014-07-16T17:34:23Z

On Wed, Jul 16, 2014 at 04:31:29PM +0200, Hannes Reinecke wrote:
> The iBFT table only specifies a prefix length, so we need to
> check the given IP address to figure out whether the netmask
> should be printed in IPv4 or IPv6 style.

Ccing netdev - maybe someone over there might be able to think of a
helper function that makes this look a little less arcane..

>
> Cc: Mike Christie <michaelc@cs.wisc.edu>
> Cc: Peter Jones <pjones@redhat.com>
> Cc: Konrad Rzeszutek Wilk <konrad@kernel.org>
> Signed-off-by: Hannes Reinecke <hare@suse.de>
> ---
> drivers/firmware/iscsi_ibft.c | 35 ++++++++++++++++++++++++++++++++---
> 1 file changed, 32 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/firmware/iscsi_ibft.c b/drivers/firmware/iscsi_ibft.c
> index 071c2c9..7fddab9 100644
> --- a/drivers/firmware/iscsi_ibft.c
> +++ b/drivers/firmware/iscsi_ibft.c
> @@ -212,6 +212,36 @@ static ssize_t sprintf_ipaddr(char *buf, u8 *ip)
> return str - buf;
> }
>
> +static ssize_t sprintf_netmask(char *buf, u8 *ip, unsigned int prefix_len)
> +{
> + char *str = buf;
> +
> + if (ip[0] == 0 && ip[1] == 0 && ip[2] == 0 && ip[3] == 0 &&
> + ip[4] == 0 && ip[5] == 0 && ip[6] == 0 && ip[7] == 0 &&
> + ip[8] == 0 && ip[9] == 0 && ip[10] == 0xff && ip[11] == 0xff) {
> + __be32 val;
> + /*
> + * IPV4
> + */
> + val = cpu_to_be32(~((1 << (32-prefix_len))-1));
> + str += sprintf(str, "%pI4", &val);
> + } else {
> + u8 netmask[16];
> + int o = prefix_len >> 3,
> + b = prefix_len & 0x7;
> + /*
> + * IPv6
> + */
> + memset(netmask, 0, 16);
> + memset(netmask, 0xff, o);
> + if (b != 0)
> + netmask[o] = 0xff & (0xff00 >> b);
> + str += sprintf(buf, "%pI6", netmask);
> + }
> + str += sprintf(str, "\n");
> + return str - buf;
> +}
> +
> static ssize_t sprintf_string(char *str, int len, char *buf)
> {
> return sprintf(str, "%.*s\n", len, buf);
> @@ -288,7 +318,6 @@ static ssize_t ibft_attr_show_nic(void *data, int type, char *buf)
> struct ibft_nic *nic = entry->nic;
> void *ibft_loc = entry->header;
> char *str = buf;
> - __be32 val;
>
> if (!nic)
> return 0;
> @@ -304,8 +333,8 @@ static ssize_t ibft_attr_show_nic(void *data, int type, char *buf)
> str += sprintf_ipaddr(str, nic->ip_addr);
> break;
> case ISCSI_BOOT_ETH_SUBNET_MASK:
> - val = cpu_to_be32(~((1 << (32-nic->subnet_mask_prefix))-1));
> - str += sprintf(str, "%pI4", &val);
> + str += sprintf_netmask(str, nic->ip_addr,
> + nic->subnet_mask_prefix);
> break;
> case ISCSI_BOOT_ETH_ORIGIN:
> str += sprintf(str, "%d\n", nic->origin);
> --
> 1.7.12.4
>
> --
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