[PATCH v3 1/3] net: Get pxe config file from dhcp option 209

seanedmond
2023-11-04T01:02:49Z

Allow dhcp server pass pxe config file full path by using option 209
as specified in RFC5071.

Signed-off-by: Sean Edmond <seanedmond@microsoft.com>
---
cmd/Kconfig | 4 ++++
cmd/pxe.c | 10 ++++++++++
net/bootp.c | 21 +++++++++++++++++++++
net/bootp.h | 2 ++
4 files changed, 37 insertions(+)

diff --git a/cmd/Kconfig b/cmd/Kconfig
index fd16c3a48e5..df6d71c103f 100644
--- a/cmd/Kconfig
+++ b/cmd/Kconfig
@@ -1840,6 +1840,10 @@ config BOOTP_PXE_CLIENTARCH
default 0x15 if ARM
default 0x0 if X86

+config BOOTP_PXE_DHCP_OPTION
+ bool "Request & store 'pxe_configfile' from BOOTP/DHCP server"
+ depends on BOOTP_PXE
+
config BOOTP_VCI_STRING
string
depends on CMD_BOOTP
diff --git a/cmd/pxe.c b/cmd/pxe.c
index 704589702f2..9404f445187 100644
--- a/cmd/pxe.c
+++ b/cmd/pxe.c
@@ -65,6 +65,8 @@ static int pxe_dhcp_option_path(struct pxe_context *ctx, unsigned long pxefile_a
int ret = get_pxe_file(ctx, pxelinux_configfile, pxefile_addr_r);

free(pxelinux_configfile);
+ /* set to NULL to avoid double-free if DHCP is tried again */
+ pxelinux_configfile = NULL;

return ret;
}
@@ -141,6 +143,14 @@ int pxe_get(ulong pxefile_addr_r, char **bootdirp, ulong *sizep, bool use_ipv6)
env_get("bootfile"), use_ipv6))
return -ENOMEM;

+ if (IS_ENABLED(CONFIG_BOOTP_PXE_DHCP_OPTION) &&
+ pxelinux_configfile && !use_ipv6) {
+ if (pxe_dhcp_option_path(&ctx, pxefile_addr_r) > 0)
+ goto done;
+
+ goto error_exit;
+ }
+
if (IS_ENABLED(CONFIG_DHCP6_PXE_DHCP_OPTION) &&
pxelinux_configfile && use_ipv6) {
if (pxe_dhcp_option_path(&ctx, pxefile_addr_r) > 0)
diff --git a/net/bootp.c b/net/bootp.c
index 7b0f45e18a9..24547cf7bfd 100644
--- a/net/bootp.c
+++ b/net/bootp.c
@@ -26,6 +26,7 @@
#ifdef CONFIG_BOOTP_RANDOM_DELAY
#include "net_rand.h"
#endif
+#include <malloc.h>

#define BOOTP_VENDOR_MAGIC 0x63825363 /* RFC1048 Magic Cookie */

@@ -601,6 +602,10 @@ static int dhcp_extended(u8 *e, int message_type, struct in_addr server_ip,
*e++ = 42;
*cnt += 1;
#endif
+ if (IS_ENABLED(CONFIG_BOOTP_PXE_DHCP_OPTION)) {
+ *e++ = DHCP_OPTION_PXE_CONFIG_FILE; /* PXELINUX Config File */
+ *cnt += 1;
+ }
/* no options, so back up to avoid sending an empty request list */
if (*cnt == 0)
e -= 2;
@@ -909,6 +914,22 @@ static void dhcp_process_options(uchar *popt, uchar *end)
net_boot_file_name[size] = 0;
}
break;
+ case DHCP_OPTION_PXE_CONFIG_FILE: /* PXELINUX Config File */
+ if (IS_ENABLED(CONFIG_BOOTP_PXE_DHCP_OPTION)) {
+ /* In case it has already been allocated when get DHCP Offer packet,
+ * free first to avoid memory leak.
+ */
+ if (pxelinux_configfile)
+ free(pxelinux_configfile);
+
+ pxelinux_configfile = (char *)malloc((oplen + 1) * sizeof(char));
+
+ if (pxelinux_configfile)
+ strlcpy(pxelinux_configfile, popt + 2, oplen + 1);
+ else
+ printf("Error: Failed to allocate pxelinux_configfile\n");
+ }
+ break;
default:
#if defined(CONFIG_BOOTP_VENDOREX)
if (dhcp_vendorex_proc(popt))
diff --git a/net/bootp.h b/net/bootp.h
index 4e32b19d424..24b32c73f62 100644
--- a/net/bootp.h
+++ b/net/bootp.h
@@ -91,6 +91,8 @@ typedef enum { INIT,
#define DHCP_NAK 6
#define DHCP_RELEASE 7

+#define DHCP_OPTION_PXE_CONFIG_FILE 209 /* "ConfigFile" option according to rfc5071 */
+
/**********************************************************************/

#endif /* __BOOTP_H__ */
--
2.42.0