From: Michael Chang <mchang@suse.com>
Date: Tue, 25 Apr 2023 11:05:18 -0400
Subject: bootp: Process DHCPACK packet during HTTP Boot

The vendor class identifier with the string "HTTPClient" is used to
denote the packet as responding to HTTP boot request.  In DHCP4 config,
the filename for HTTP boot is the URL of the boot file, while for PXE
boot it is the path to the boot file.  As a consequence, the next-server
becomes obselete because the HTTP URL already contains the server
address for the boot file.  For DHCP6 config, there's no difference
definition in existing config as dhcp6.bootfile-url can be used to
specify URL for both HTTP and PXE boot file.

Add processing for "HTTPClient" vendor class identifier in DHCPACK
packet by treating it as HTTP format, not as the PXE format.

Signed-off-by: Michael Chang <mchang@suse.com>
Signed-off-by: Ken Lin <ken.lin@hpe.com>
Signed-off-by: Robbie Harwood <rharwood@redhat.com>
---
 grub-core/net/bootp.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++
 include/grub/net.h    |  1 +
 2 files changed, 56 insertions(+)

diff --git a/grub-core/net/bootp.c b/grub-core/net/bootp.c
index 12996a7..563d333 100644
--- a/grub-core/net/bootp.c
+++ b/grub-core/net/bootp.c
@@ -20,6 +20,7 @@
 #include <grub/env.h>
 #include <grub/i18n.h>
 #include <grub/command.h>
+#include <grub/net.h>
 #include <grub/net/ip.h>
 #include <grub/net/netbuff.h>
 #include <grub/net/udp.h>
@@ -506,6 +507,60 @@ grub_net_configure_by_dhcp_ack (const char *name,
   if (opt && opt_len)
     grub_env_set_net_property (name, "rootpath", (const char *) opt, opt_len);
 
+  opt = find_dhcp_option (bp, size, GRUB_NET_BOOTP_VENDOR_CLASS_IDENTIFIER, &opt_len);
+  if (opt && opt_len)
+    {
+      grub_env_set_net_property (name, "vendor_class_identifier", (const char *) opt, opt_len);
+      if (opt && grub_strcmp ((const char *) opt, "HTTPClient") == 0)
+        {
+          char *proto, *ip, *pa;
+
+          if (!dissect_url (bp->boot_file, &proto, &ip, &pa))
+            return inter;
+
+          grub_env_set_net_property (name, "boot_file", pa, grub_strlen (pa));
+          if (is_def)
+            {
+              grub_net_default_server = grub_strdup (ip);
+              grub_env_set ("net_default_interface", name);
+              grub_env_export ("net_default_interface");
+            }
+          if (device && !*device)
+            {
+              *device = grub_xasprintf ("%s,%s", proto, ip);
+              grub_print_error ();
+            }
+          if (path)
+            {
+              *path = grub_strdup (pa);
+              grub_print_error ();
+              if (*path)
+                {
+                  char *slash;
+                  slash = grub_strrchr (*path, '/');
+                  if (slash)
+                    *slash = 0;
+                  else
+                    **path = 0;
+                }
+            }
+          grub_net_add_ipv4_local (inter, mask);
+          inter->dhcp_ack = grub_malloc (size);
+          if (inter->dhcp_ack)
+            {
+              grub_memcpy (inter->dhcp_ack, bp, size);
+              inter->dhcp_acklen = size;
+            }
+          else
+            grub_errno = GRUB_ERR_NONE;
+
+          grub_free (proto);
+          grub_free (ip);
+          grub_free (pa);
+          return inter;
+        }
+    }
+
   opt = find_dhcp_option (bp, size, GRUB_NET_BOOTP_EXTENSIONS_PATH, &opt_len);
   if (opt && opt_len)
     grub_env_set_net_property (name, "extensionspath", (const char *) opt, opt_len);
diff --git a/include/grub/net.h b/include/grub/net.h
index 3e2704e..e7d75b9 100644
--- a/include/grub/net.h
+++ b/include/grub/net.h
@@ -530,6 +530,7 @@ enum
     GRUB_NET_DHCP_MESSAGE_TYPE = 53,
     GRUB_NET_DHCP_SERVER_IDENTIFIER = 54,
     GRUB_NET_DHCP_PARAMETER_REQUEST_LIST = 55,
+    GRUB_NET_BOOTP_VENDOR_CLASS_IDENTIFIER = 60,
     GRUB_NET_BOOTP_CLIENT_ID = 61,
     GRUB_NET_DHCP_TFTP_SERVER_NAME = 66,
     GRUB_NET_DHCP_BOOTFILE_NAME = 67,