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[PATCH v3 07/10] net: dhcp: use DHCP options for name and bootfile
From: |
Andre Przywara |
Subject: |
[PATCH v3 07/10] net: dhcp: use DHCP options for name and bootfile |
Date: |
Thu, 7 Mar 2019 15:14:13 +0000 |
From: Andrei Borzenkov <address@hidden>
The BOOTP RFC describes the boot file name and the server name as being
part of the integral BOOTP data structure, with some limits on the size
of them.
DHCP extends this by allowing them to be separate DHCP options, which is
more flexible.
Teach the code dealing with those fields to check for those DHCP options
first and use this information, if provided. We fall back to using the
BOOTP information if those options are not used.
Signed-off-by: Andre Przywara <address@hidden>
---
grub-core/net/bootp.c | 72 +++++++++++++++++++++++++++++++------------
include/grub/net.h | 2 ++
2 files changed, 54 insertions(+), 20 deletions(-)
diff --git a/grub-core/net/bootp.c b/grub-core/net/bootp.c
index 2fb79d162..bfde6ef10 100644
--- a/grub-core/net/bootp.c
+++ b/grub-core/net/bootp.c
@@ -168,7 +168,9 @@ grub_net_configure_by_dhcp_ack (const char *name,
int mask = -1;
char server_ip[sizeof ("xxx.xxx.xxx.xxx")];
const grub_uint8_t *opt;
- grub_uint8_t opt_len;
+ grub_uint8_t opt_len, overload = 0;
+ const char *boot_file = 0, *server_name = 0;
+ grub_size_t boot_file_len, server_name_len;
addr.type = GRUB_NET_NETWORK_LEVEL_PROTOCOL_IPV4;
addr.ipv4 = bp->your_ip;
@@ -187,9 +189,36 @@ grub_net_configure_by_dhcp_ack (const char *name,
if (!inter)
return 0;
- if (size > OFFSET_OF (boot_file, bp))
- grub_env_set_net_property (name, "boot_file", bp->boot_file,
- sizeof (bp->boot_file));
+ opt = find_dhcp_option (bp, size, GRUB_NET_DHCP_OVERLOAD, &opt_len);
+ if (opt && opt_len == 1)
+ overload = *opt;
+
+ opt = find_dhcp_option (bp, size, GRUB_NET_DHCP_TFTP_SERVER_NAME, &opt_len);
+ if (opt && opt_len)
+ {
+ server_name = (const char *) opt;
+ server_name_len = opt_len;
+ }
+ else if (size > OFFSET_OF (server_name, bp) && !(overload &
GRUB_DHCP_OPT_OVERLOAD_SNAME) &&
+ bp->server_name[0])
+ {
+ server_name = bp->server_name;
+ server_name_len = sizeof (bp->server_name);
+ }
+
+ opt = find_dhcp_option (bp, size, GRUB_NET_DHCP_BOOTFILE_NAME, &opt_len);
+ if (opt && opt_len)
+ {
+ boot_file = (const char *) opt;
+ boot_file_len = opt_len;
+ }
+ else if (size > OFFSET_OF (boot_file, bp) && !(overload &&
GRUB_DHCP_OPT_OVERLOAD_FILE) &&
+ bp->boot_file[0])
+ {
+ boot_file = bp->boot_file;
+ boot_file_len = sizeof (bp->boot_file);
+ }
+
if (bp->server_ip)
{
grub_snprintf (server_ip, sizeof (server_ip), "%d.%d.%d.%d",
@@ -220,35 +249,38 @@ grub_net_configure_by_dhcp_ack (const char *name,
*device = grub_xasprintf ("tftp,%s", server_ip);
grub_print_error ();
}
- if (size > OFFSET_OF (server_name, bp)
- && bp->server_name[0])
+
+ if (server_name)
{
- grub_env_set_net_property (name, "dhcp_server_name", bp->server_name,
- sizeof (bp->server_name));
+ grub_env_set_net_property (name, "dhcp_server_name", server_name,
server_name_len);
if (is_def && !grub_net_default_server)
{
- grub_net_default_server = grub_strdup (bp->server_name);
+ grub_net_default_server = grub_strdup (server_name);
grub_print_error ();
}
if (device && !*device)
{
- *device = grub_xasprintf ("tftp,%s", bp->server_name);
+ *device = grub_xasprintf ("tftp,%s", server_name);
grub_print_error ();
}
}
- if (size > OFFSET_OF (boot_file, bp) && path)
+ if (boot_file)
{
- *path = grub_strndup (bp->boot_file, sizeof (bp->boot_file));
- grub_print_error ();
- if (*path)
+ grub_env_set_net_property (name, "boot_file", boot_file, boot_file_len);
+ if (path)
{
- char *slash;
- slash = grub_strrchr (*path, '/');
- if (slash)
- *slash = 0;
- else
- **path = 0;
+ *path = grub_strndup (boot_file, boot_file_len);
+ grub_print_error ();
+ if (*path)
+ {
+ char *slash;
+ slash = grub_strrchr (*path, '/');
+ if (slash)
+ *slash = 0;
+ else
+ **path = 0;
+ }
}
}
diff --git a/include/grub/net.h b/include/grub/net.h
index a1138f5d4..f7b546446 100644
--- a/include/grub/net.h
+++ b/include/grub/net.h
@@ -460,6 +460,8 @@ enum
GRUB_NET_BOOTP_ROOT_PATH = 0x11,
GRUB_NET_BOOTP_EXTENSIONS_PATH = 0x12,
GRUB_NET_DHCP_OVERLOAD = 52,
+ GRUB_NET_DHCP_TFTP_SERVER_NAME = 66,
+ GRUB_NET_DHCP_BOOTFILE_NAME = 67,
GRUB_NET_BOOTP_END = 0xff
};
--
2.17.1
[PATCH v3 09/10] net: dhcp: actually send out DHCPv4 DISCOVER and REQUEST messages, Andre Przywara, 2019/03/07
[PATCH v3 06/10] net: dhcp: introduce per-interface timeout, Andre Przywara, 2019/03/07
[PATCH v3 10/10] net: dhcp: add explicit net_dhcp command, Andre Przywara, 2019/03/07
Re: [PATCH v3 00/10] net: bootp: add native DHCPv4 support, Daniel Kiper, 2019/03/08