[CHERRY-PICK] NetworkPkg/HttpBootDxe: Wait for IPv6 DAD before issuing DHCPv6 requests

Align HTTP Boot behavior with PXE by inserting a delay to wait for IPv6 Duplicate Address Detection (DAD) to complete before issuing DHCPv6 requests. This avoids EFI_NO_MAPPING errors caused by early DHCP attempts before a valid IPv6 address is ready.

Problem:
On some platforms, HTTP boot over IPv6 fails with EFI_NO_MAPPING during initial DHCPv6 attempts. The failure is due to the system trying to send Solicit messages before IPv6 DAD finishes, resulting in no usable IP address at that time.

Solution:
Insert a retry mechanism to poll DAD completion when the initial call to Dhcp6->Start() fails with EFI_NO_MAPPING. This behavior mirrors PXE's handling, where it waits for a valid IPv6 address to be assigned before retrying the DHCPv6 flow.

Signed-off-by: Sam Tsai [Wiwynn] <[email protected]>
(cherry picked from commit 11f1d28)

Author: samtsai0121

NetworkPkg/HttpBootDxe/HttpBootDhcp6.c

@@ -930,6 +930,82 @@ HttpBootSetIp6Address (
   return Status;
 }
 
+/**
+  Retry DHCPv6 when EFI_NO_MAPPING is returned, by waiting for Duplicate Address
+  Detection (DAD) to complete and restarting the DHCPv6 process.
+
+  This function stops the current DHCP6 session and waits for DAD to complete
+  based on the value returned by Ip6Config->GetData(), then retries Dhcp6->Start().
+
+  @param[in]  Dhcp6     The pointer to the EFI_DHCP6_PROTOCOL instance.
+  @param[in]  Ip6Cfg    The pointer to the EFI_IP6_CONFIG_PROTOCOL instance.
+
+  @retval EFI_SUCCESS           DHCPv6 process restarted successfully after DAD.
+  @retval EFI_DEVICE_ERROR      Failed during DAD timer wait or DHCP restart.
+  @retval EFI_OUT_OF_RESOURCES  Failed to allocate timer resources.
+  @retval Others                Underlying protocol errors.
+
+**/
+EFI_STATUS
+HandleDhcp6NoMappingRetry (
+  IN EFI_DHCP6_PROTOCOL       *Dhcp6,
+  IN EFI_IP6_CONFIG_PROTOCOL  *Ip6Cfg
+  )
+{
+  EFI_STATUS                                Status;
+  EFI_STATUS                                TimerStatus;
+  EFI_EVENT                                 Timer = NULL;
+  UINT64                                    GetMappingTimeOut;
+  UINTN                                     DataSize;
+  EFI_IP6_CONFIG_DUP_ADDR_DETECT_TRANSMITS  DadXmits;
+
+  //
+  // IP6 Linklocal address is not available for use, so stop current Dhcp process
+  // and wait for duplicate address detection to finish.
+  //
+  Dhcp6->Stop (Dhcp6);
+
+  //
+  // Get Duplicate Address Detection Transmits count.
+  //
+  DataSize = sizeof (EFI_IP6_CONFIG_DUP_ADDR_DETECT_TRANSMITS);
+  Status   = Ip6Cfg->GetData (
+                       Ip6Cfg,
+                       Ip6ConfigDataTypeDupAddrDetectTransmits,
+                       &DataSize,
+                       &DadXmits
+                       );
+  if (EFI_ERROR (Status)) {
+    Dhcp6->Configure (Dhcp6, NULL);
+    return Status;
+  }
+
+  Status = gBS->CreateEvent (EVT_TIMER, TPL_CALLBACK, NULL, NULL, &Timer);
+  if (EFI_ERROR (Status)) {
+    Dhcp6->Configure (Dhcp6, NULL);
+    return Status;
+  }
+
+  GetMappingTimeOut = TICKS_PER_SECOND * DadXmits.DupAddrDetectTransmits + HTTP_BOOT_DAD_ADDITIONAL_DELAY;
+  Status            = gBS->SetTimer (Timer, TimerRelative, GetMappingTimeOut);
+  if (EFI_ERROR (Status)) {
+    gBS->CloseEvent (Timer);
+    Dhcp6->Configure (Dhcp6, NULL);
+    return Status;
+  }
+
+  do {
+    TimerStatus = gBS->CheckEvent (Timer);
+    if (!EFI_ERROR (TimerStatus)) {
+      Status = Dhcp6->Start (Dhcp6);
+    }
+  } while (TimerStatus == EFI_NOT_READY);
+
+  gBS->CloseEvent (Timer);
+
+  return Status;
+}
+
 /**
   Start the S.A.R.R DHCPv6 process to acquire the IPv6 address and other Http boot information.
 
@@ -953,10 +1029,14 @@ HttpBootDhcp6Sarr (
   UINT8                     Buffer[HTTP_BOOT_DHCP6_OPTION_MAX_SIZE];
   EFI_STATUS                Status;
   UINT32                    Random;
+  EFI_IP6_CONFIG_PROTOCOL   *Ip6Cfg;
 
   Dhcp6 = Private->Dhcp6;
   ASSERT (Dhcp6 != NULL);
 
+  ASSERT (Private->UsingIpv6);
+  Ip6Cfg = Private->Ip6Config;
+
   //
   // Build options list for the request packet.
   //
@@ -1013,6 +1093,10 @@ HttpBootDhcp6Sarr (
   // Start DHCPv6 S.A.R.R. process to acquire IPv6 address.
   //
   Status = Dhcp6->Start (Dhcp6);
+  if (Status == EFI_NO_MAPPING) {
+    Status = HandleDhcp6NoMappingRetry (Dhcp6, Ip6Cfg);
+  }
+
   if (EFI_ERROR (Status)) {
     goto ON_EXIT;
   }

NetworkPkg/HttpBootDxe/HttpBootDhcp6.h

@@ -16,6 +16,7 @@ SPDX-License-Identifier: BSD-2-Clause-Patent
 #define HTTP_BOOT_IP6_ROUTE_TABLE_TIMEOUT  10
 #define HTTP_BOOT_DEFAULT_HOPLIMIT         64
 #define HTTP_BOOT_DEFAULT_LIFETIME         50000
+#define HTTP_BOOT_DAD_ADDITIONAL_DELAY     30000000   // 3 seconds
 
 #define HTTP_BOOT_DHCP6_ENTERPRISE_NUM      343     // TODO: IANA TBD: temporarily using Intel's
 #define HTTP_BOOT_DHCP6_MAX_BOOT_FILE_SIZE  65535   //   It's a limitation of bit length, 65535*512 bytes.