From: Michael Chang <mchang@suse.com>
Date: Tue, 25 Apr 2023 11:05:20 -0400
Subject: efinet: set DNS server from UEFI protocol

In the URI device path node, any name rather than address can be used
for looking up the resources so that DNS service become needed to get
answer of the name's address.  Unfortunately, DNS is not defined in any
of the device path nodes so that we use the EFI_IP4_CONFIG2_PROTOCOL and
EFI_IP6_CONFIG_PROTOCOL to obtain it.

These two protcols are defined the sections of UEFI specification.

    27.5 EFI IPv4 Configuration II Protocol
    27.7 EFI IPv6 Configuration Protocol

include/grub/efi/api.h:
Add new structure and protocol UUID of EFI_IP4_CONFIG2_PROTOCOL and
EFI_IP6_CONFIG_PROTOCOL.

grub-core/net/drivers/efi/efinet.c:
Use the EFI_IP4_CONFIG2_PROTOCOL and EFI_IP6_CONFIG_PROTOCOL to obtain
the list of DNS server address for IPv4 and IPv6 respectively.  The
address of DNS servers is structured into DHCPACK packet and feed into
the same DHCP packet processing functions to ensure the network
interface is setting up the same way it used to be.

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>
Signed-off-by: Julian Andres Klode <julian.klode@canonical.com>
(rebased against 2.12)
---
 grub-core/net/drivers/efi/efinet.c | 160 +++++++++++++++++++++++++++++++++++++
 include/grub/efi/api.h             |  77 ++++++++++++++++++
 2 files changed, 237 insertions(+)

diff --git a/grub-core/net/drivers/efi/efinet.c b/grub-core/net/drivers/efi/efinet.c
index 3dbe880..3a4a92f 100644
--- a/grub-core/net/drivers/efi/efinet.c
+++ b/grub-core/net/drivers/efi/efinet.c
@@ -33,6 +33,8 @@ GRUB_MOD_LICENSE ("GPLv3+");
 /* GUID.  */
 static grub_guid_t net_io_guid = GRUB_EFI_SIMPLE_NETWORK_GUID;
 static grub_guid_t pxe_io_guid = GRUB_EFI_PXE_GUID;
+static grub_guid_t ip4_config_guid = GRUB_EFI_IP4_CONFIG2_PROTOCOL_GUID;
+static grub_guid_t ip6_config_guid = GRUB_EFI_IP6_CONFIG_PROTOCOL_GUID;
 
 static grub_err_t
 send_card_buffer (struct grub_net_card *dev,
@@ -345,6 +347,122 @@ grub_efinet_findcards (void)
   grub_free (handles);
 }
 
+static grub_efi_handle_t
+grub_efi_locate_device_path (grub_guid_t *protocol, grub_efi_device_path_t *device_path,
+			    grub_efi_device_path_t **r_device_path)
+{
+  grub_efi_handle_t handle;
+  grub_efi_status_t status;
+
+  status = grub_efi_system_table->boot_services->locate_device_path(
+                       protocol, &device_path, &handle);
+
+  if (status != GRUB_EFI_SUCCESS)
+    return 0;
+
+  if (r_device_path)
+    *r_device_path = device_path;
+
+  return handle;
+}
+
+static grub_efi_ipv4_address_t *
+grub_dns_server_ip4_address (grub_efi_device_path_t *dp, grub_efi_uintn_t *num_dns)
+{
+  grub_efi_handle_t hnd;
+  grub_efi_status_t status;
+  grub_efi_ip4_config2_protocol_t *conf;
+  grub_efi_ipv4_address_t *addrs;
+  grub_efi_uintn_t data_size = 1 * sizeof (grub_efi_ipv4_address_t);
+
+  hnd = grub_efi_locate_device_path (&ip4_config_guid, dp, NULL);
+  if (!hnd)
+    return 0;
+
+  conf = grub_efi_open_protocol (hnd, &ip4_config_guid,
+                                 GRUB_EFI_OPEN_PROTOCOL_GET_PROTOCOL);
+  if (!conf)
+    return 0;
+
+  addrs  = grub_malloc (data_size);
+  if (!addrs)
+    return 0;
+
+  status = conf->get_data(conf,
+                       GRUB_EFI_IP4_CONFIG2_DATA_TYPE_DNSSERVER,
+                       &data_size, addrs);
+
+  if (status == GRUB_EFI_BUFFER_TOO_SMALL)
+    {
+      grub_free (addrs);
+      addrs = grub_malloc (data_size);
+      if (!addrs)
+	return 0;
+
+      status = conf->get_data(conf,
+                           GRUB_EFI_IP4_CONFIG2_DATA_TYPE_DNSSERVER,
+                           &data_size, addrs);
+    }
+
+  if (status != GRUB_EFI_SUCCESS)
+    {
+      grub_free (addrs);
+      return 0;
+    }
+
+  *num_dns = data_size / sizeof (grub_efi_ipv4_address_t);
+  return addrs;
+}
+
+static grub_efi_ipv6_address_t *
+grub_dns_server_ip6_address (grub_efi_device_path_t *dp, grub_efi_uintn_t *num_dns)
+{
+  grub_efi_handle_t hnd;
+  grub_efi_status_t status;
+  grub_efi_ip6_config_protocol_t *conf;
+  grub_efi_ipv6_address_t *addrs;
+  grub_efi_uintn_t data_size = 1 * sizeof (grub_efi_ipv6_address_t);
+
+  hnd = grub_efi_locate_device_path (&ip6_config_guid, dp, NULL);
+  if (!hnd)
+    return 0;
+
+  conf = grub_efi_open_protocol (hnd, &ip6_config_guid,
+                                 GRUB_EFI_OPEN_PROTOCOL_GET_PROTOCOL);
+
+  if (!conf)
+    return 0;
+
+  addrs = grub_malloc (data_size);
+  if (!addrs)
+    return 0;
+
+  status = conf->get_data(conf,
+                       GRUB_EFI_IP6_CONFIG_DATA_TYPE_DNSSERVER,
+                       &data_size, addrs);
+
+  if (status == GRUB_EFI_BUFFER_TOO_SMALL)
+    {
+      grub_free (addrs);
+      addrs = grub_malloc (data_size);
+      if (!addrs)
+	return 0;
+
+      status = conf->get_data(conf,
+                           GRUB_EFI_IP6_CONFIG_DATA_TYPE_DNSSERVER,
+                           &data_size, addrs);
+    }
+
+  if (status != GRUB_EFI_SUCCESS)
+    {
+      grub_free (addrs);
+      return 0;
+    }
+
+  *num_dns = data_size / sizeof (grub_efi_ipv6_address_t);
+  return addrs;
+}
+
 static struct grub_net_buff *
 grub_efinet_create_dhcp_ack_from_device_path (grub_efi_device_path_t *dp, int *use_ipv6)
 {
@@ -401,6 +519,8 @@ grub_efinet_create_dhcp_ack_from_device_path (grub_efi_device_path_t *dp, int *u
       grub_efi_ipv4_device_path_t *ipv4 = (grub_efi_ipv4_device_path_t *) ldp;
       struct grub_net_bootp_packet *bp;
       grub_uint8_t *ptr;
+      grub_efi_ipv4_address_t *dns;
+      grub_efi_uintn_t num_dns;
 
       bp = (struct grub_net_bootp_packet *) nb->tail;
       err = grub_netbuff_put (nb, sizeof (*bp) + 4);
@@ -462,6 +582,25 @@ grub_efinet_create_dhcp_ack_from_device_path (grub_efi_device_path_t *dp, int *u
       *ptr++ = sizeof ("HTTPClient") - 1;
       grub_memcpy (ptr, "HTTPClient", sizeof ("HTTPClient") - 1);
 
+      dns = grub_dns_server_ip4_address (dp, &num_dns);
+      if (dns)
+	{
+	  grub_efi_uintn_t size_dns = sizeof (*dns) * num_dns;
+
+	  ptr = nb->tail;
+	  err = grub_netbuff_put (nb, size_dns + 2);
+	  if (err)
+	    {
+	      grub_free (ddp);
+	      grub_netbuff_free (nb);
+	      return NULL;
+	    }
+	  *ptr++ = GRUB_NET_BOOTP_DNS;
+	  *ptr++ = size_dns;
+	  grub_memcpy (ptr, dns, size_dns);
+	  grub_free (dns);
+	}
+
       ptr = nb->tail;
       err = grub_netbuff_put (nb, 1);
       if (err)
@@ -494,6 +633,8 @@ grub_efinet_create_dhcp_ack_from_device_path (grub_efi_device_path_t *dp, int *u
       struct grub_net_dhcp6_option *opt;
       struct grub_net_dhcp6_option_iana *iana;
       struct grub_net_dhcp6_option_iaaddr *iaaddr;
+      grub_efi_ipv6_address_t *dns;
+      grub_efi_uintn_t num_dns;
 
       d6p = (struct grub_net_dhcp6_packet *)nb->tail;
       err = grub_netbuff_put (nb, sizeof(*d6p));
@@ -557,6 +698,25 @@ grub_efinet_create_dhcp_ack_from_device_path (grub_efi_device_path_t *dp, int *u
       opt->len = grub_cpu_to_be16 (uri_len);
       grub_memcpy (opt->data, uri_dp->uri, uri_len);
 
+      dns = grub_dns_server_ip6_address (dp, &num_dns);
+      if (dns)
+	{
+	  grub_efi_uintn_t size_dns = sizeof (*dns) * num_dns;
+
+	  opt = (struct grub_net_dhcp6_option *) nb->tail;
+	  err = grub_netbuff_put (nb, sizeof (*opt) + size_dns);
+	  if (err)
+            {
+              grub_free (ddp);
+              grub_netbuff_free (nb);
+              return NULL;
+            }
+	  opt->code = grub_cpu_to_be16_compile_time (GRUB_NET_DHCP6_OPTION_DNS_SERVERS);
+	  opt->len = grub_cpu_to_be16 (size_dns);
+	  grub_memcpy (opt->data, dns, size_dns);
+	  grub_free (dns);
+	}
+
       *use_ipv6 = 1;
     }
 
diff --git a/include/grub/efi/api.h b/include/grub/efi/api.h
index 9515d56..b64fd49 100644
--- a/include/grub/efi/api.h
+++ b/include/grub/efi/api.h
@@ -367,6 +367,15 @@
 #define GRUB_EFI_RNG_PROTOCOL_GUID \
   { 0x3152bca5, 0xeade, 0x433d, \
     { 0x86, 0x2e, 0xc0, 0x1c, 0xdc, 0x29, 0x1f, 0x44 } \
+
+#define GRUB_EFI_IP4_CONFIG2_PROTOCOL_GUID \
+  { 0x5b446ed1, 0xe30b, 0x4faa, \
+      { 0x87, 0x1a, 0x36, 0x54, 0xec, 0xa3, 0x60, 0x80 } \
+  }
+
+#define GRUB_EFI_IP6_CONFIG_PROTOCOL_GUID \
+  { 0x937fe521, 0x95ae, 0x4d1a, \
+      { 0x89, 0x29, 0x48, 0xbc, 0xd9, 0x0a, 0xd3, 0x1a } \
   }
 
 #define LINUX_EFI_INITRD_MEDIA_GUID  \
@@ -1944,6 +1953,74 @@ struct grub_efi_rng_protocol
 };
 typedef struct grub_efi_rng_protocol grub_efi_rng_protocol_t;
 
+enum grub_efi_ip4_config2_data_type
+  {
+    GRUB_EFI_IP4_CONFIG2_DATA_TYPE_INTERFACEINFO,
+    GRUB_EFI_IP4_CONFIG2_DATA_TYPE_POLICY,
+    GRUB_EFI_IP4_CONFIG2_DATA_TYPE_MANUAL_ADDRESS,
+    GRUB_EFI_IP4_CONFIG2_DATA_TYPE_GATEWAY,
+    GRUB_EFI_IP4_CONFIG2_DATA_TYPE_DNSSERVER,
+    GRUB_EFI_IP4_CONFIG2_DATA_TYPE_MAXIMUM,
+  };
+typedef enum grub_efi_ip4_config2_data_type grub_efi_ip4_config2_data_type_t;
+
+struct grub_efi_ip4_config2_protocol
+{
+  grub_efi_status_t (__grub_efi_api *set_data) (struct grub_efi_ip4_config2_protocol *this,
+				 grub_efi_ip4_config2_data_type_t data_type,
+				 grub_efi_uintn_t data_size,
+				 void *data);
+
+  grub_efi_status_t (__grub_efi_api *get_data) (struct grub_efi_ip4_config2_protocol *this,
+				 grub_efi_ip4_config2_data_type_t data_type,
+				 grub_efi_uintn_t *data_size,
+				 void *data);
+
+  grub_efi_status_t (__grub_efi_api *register_data_notify) (struct grub_efi_ip4_config2_protocol *this,
+					     grub_efi_ip4_config2_data_type_t data_type,
+					     grub_efi_event_t event);
+
+  grub_efi_status_t (__grub_efi_api *unregister_datanotify) (struct grub_efi_ip4_config2_protocol *this,
+					     grub_efi_ip4_config2_data_type_t data_type,
+					     grub_efi_event_t event);
+};
+typedef struct grub_efi_ip4_config2_protocol grub_efi_ip4_config2_protocol_t;
+
+enum grub_efi_ip6_config_data_type
+  {
+    GRUB_EFI_IP6_CONFIG_DATA_TYPE_INTERFACEINFO,
+    GRUB_EFI_IP6_CONFIG_DATA_TYPE_ALT_INTERFACEID,
+    GRUB_EFI_IP6_CONFIG_DATA_TYPE_POLICY,
+    GRUB_EFI_IP6_CONFIG_DATA_TYPE_DUP_ADDR_DETECT_TRANSMITS,
+    GRUB_EFI_IP6_CONFIG_DATA_TYPE_MANUAL_ADDRESS,
+    GRUB_EFI_IP6_CONFIG_DATA_TYPE_GATEWAY,
+    GRUB_EFI_IP6_CONFIG_DATA_TYPE_DNSSERVER,
+    GRUB_EFI_IP6_CONFIG_DATA_TYPE_MAXIMUM,
+  };
+typedef enum grub_efi_ip6_config_data_type grub_efi_ip6_config_data_type_t;
+
+struct grub_efi_ip6_config_protocol
+{
+  grub_efi_status_t (__grub_efi_api *set_data) (struct grub_efi_ip6_config_protocol *this,
+				 grub_efi_ip6_config_data_type_t data_type,
+				 grub_efi_uintn_t data_size,
+				 void *data);
+
+  grub_efi_status_t (__grub_efi_api *get_data) (struct grub_efi_ip6_config_protocol *this,
+				 grub_efi_ip6_config_data_type_t data_type,
+				 grub_efi_uintn_t *data_size,
+				 void *data);
+
+  grub_efi_status_t (__grub_efi_api *register_data_notify) (struct grub_efi_ip6_config_protocol *this,
+					     grub_efi_ip6_config_data_type_t data_type,
+					     grub_efi_event_t event);
+
+  grub_efi_status_t (__grub_efi_api *unregister_datanotify) (struct grub_efi_ip6_config_protocol *this,
+					     grub_efi_ip6_config_data_type_t data_type,
+					     grub_efi_event_t event);
+};
+typedef struct grub_efi_ip6_config_protocol grub_efi_ip6_config_protocol_t;
+
 struct grub_efi_load_file2
 {
   grub_efi_status_t (__grub_efi_api *load_file)(struct grub_efi_load_file2 *this,