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bootp: export next server IP as environment variable

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Network boot autoconfiguration sets default server to next server IP
(siaddr) from BOOTP/DHCP reply, but manual configuration using net_bootp
exports only server name. Unfortunately semantic of server name is not
clearly defined. BOOTP RFC 951 defines it only for client request, and
DHCP RFC 1541 only mentions it, without any implied usage. It looks like
this field is mostly empty in server replies.

Export next server IP as net_<interface>_next_server variable. This allows
grub configuration script to set $root/$prefix based on information obtained
by net_bootp.

Reported and tested by: Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>
Cc: nikunj@linux.vnet.ibm.com

v2: change variable name to net_<interface>_next_server as discussed on the list
This commit is contained in:
Andrei Borzenkov 2016-11-22 20:42:23 +03:00
parent 0af7539bd2
commit f8c3af3b61
2 changed files with 25 additions and 10 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

11
docs/grub.texi
View file

@ -2446,6 +2446,10 @@ The boot file name provided by DHCP. Read-only.
The name of the DHCP server responsible for these boot parameters.
Read-only.
@item net_@var{<interface>}_next_server
The IP address of the next (usually, TFTP) server provided by DHCP.
Read-only.
@item net_default_interface
Initially set to name of network interface that was used to load grub.
Read-write, although setting it affects only interpretation of
@ -3062,6 +3066,7 @@ These variables have special meaning to GRUB.
* net_@var{<interface>}_hostname::
* net_@var{<interface>}_ip::
* net_@var{<interface>}_mac::
* net_@var{<interface>}_next_server::
* net_@var{<interface>}_rootpath::
* net_default_interface::
* net_default_ip::
@ -3422,6 +3427,12 @@ The default is the value of @samp{color_normal} (@pxref{color_normal}).
@xref{Network}.
@node net_@var{<interface>}_next_server
@subsection net_@var{<interface>}_next_server
@xref{Network}.
@node net_@var{<interface>}_rootpath
@subsection net_@var{<interface>}_rootpath

24
grub-core/net/bootp.c
View file

@ -142,6 +142,7 @@ grub_net_configure_by_dhcp_ack (const char *name,
grub_net_link_level_address_t hwaddr;
struct grub_net_network_level_interface *inter;
int mask = -1;
char server_ip[sizeof ("xxx.xxx.xxx.xxx")];
addr.type = GRUB_NET_NETWORK_LEVEL_PROTOCOL_IPV4;
addr.ipv4 = bp->your_ip;
@ -192,15 +193,22 @@ grub_net_configure_by_dhcp_ack (const char *name,
if (size > OFFSET_OF (boot_file, bp))
grub_env_set_net_property (name, "boot_file", bp->boot_file,
sizeof (bp->boot_file));
if (bp->server_ip)
{
grub_snprintf (server_ip, sizeof (server_ip), "%d.%d.%d.%d",
((grub_uint8_t *) &bp->server_ip)[0],
((grub_uint8_t *) &bp->server_ip)[1],
((grub_uint8_t *) &bp->server_ip)[2],
((grub_uint8_t *) &bp->server_ip)[3]);
grub_env_set_net_property (name, "next_server", server_ip, sizeof (server_ip));
grub_print_error ();
}
if (is_def)
grub_net_default_server = 0;
if (is_def && !grub_net_default_server && bp->server_ip)
{
grub_net_default_server = grub_xasprintf ("%d.%d.%d.%d",
((grub_uint8_t *) &bp->server_ip)[0],
((grub_uint8_t *) &bp->server_ip)[1],
((grub_uint8_t *) &bp->server_ip)[2],
((grub_uint8_t *) &bp->server_ip)[3]);
grub_net_default_server = grub_strdup (server_ip);
grub_print_error ();
}
@ -212,11 +220,7 @@ grub_net_configure_by_dhcp_ack (const char *name,
if (device && !*device && bp->server_ip)
{
*device = grub_xasprintf ("tftp,%d.%d.%d.%d",
((grub_uint8_t *) &bp->server_ip)[0],
((grub_uint8_t *) &bp->server_ip)[1],
((grub_uint8_t *) &bp->server_ip)[2],
((grub_uint8_t *) &bp->server_ip)[3]);
*device = grub_xasprintf ("tftp,%s", server_ip);
grub_print_error ();
}
if (size > OFFSET_OF (server_name, bp)