[PATCH v2 1/3] net: Get pxe config file from dhcp option 209

[seanedmond]

From: Sean Edmond <seanedm...@microsoft.com>

Allow dhcp server pass pxe config file full path by using option 209

Signed-off-by: Sean Edmond <seanedm...@microsoft.com>
---
 cmd/Kconfig |  4 ++++
 cmd/pxe.c   | 10 ++++++++++
 net/bootp.c | 21 +++++++++++++++++++++
 3 files changed, 35 insertions(+)

diff --git a/cmd/Kconfig b/cmd/Kconfig
index 5bc0a92d57..adbb1a6187 100644
--- a/cmd/Kconfig
+++ b/cmd/Kconfig
@@ -1826,6 +1826,10 @@ 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 704589702f..9404f44518 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 7b0f45e18a..6800290963 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++ = 209;     /* 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 209:       /* 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))
-- 
2.40.0