From dcad73ca5ad3e1fe011c52a24036f67ad69fadc1 Mon Sep 17 00:00:00 2001
From: Michael Brown
Date: Fri, 22 Mar 2024 15:30:45 +0000
Subject: [efi] Add support for driving EFI_MANAGED_NETWORK_PROTOCOL devices

We want exclusive access to the network device, both for performance
reasons and because we perform operations such as EAPoL that affect
the entire link.  We currently drive the network card via either a
native hardware driver or via the SNP or NII/UNDI interfaces, both of
which grant us this exclusive access.

Add an alternative driver that drives the network card non-exclusively
via the EFI_MANAGED_NETWORK_PROTOCOL interface.  This can function as
a fallback for situations where neither SNP nor NII/UNDI interfaces
are functional, and also opens up the possibility of non-destructively
installing a temporary network device over which to download the
autoexec.ipxe script.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
---
 src/drivers/net/efi/snp.c | 54 ++---------------------------------------------
 1 file changed, 2 insertions(+), 52 deletions(-)

(limited to 'src/drivers/net/efi/snp.c')

diff --git a/src/drivers/net/efi/snp.c b/src/drivers/net/efi/snp.c
index 1920cdbc..cac8b38e 100644
--- a/src/drivers/net/efi/snp.c
+++ b/src/drivers/net/efi/snp.c
@@ -23,11 +23,8 @@
 
 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 
-#include <errno.h>
 #include <ipxe/efi/efi.h>
 #include <ipxe/efi/efi_driver.h>
-#include <ipxe/efi/efi_snp.h>
-#include <ipxe/efi/efi_utils.h>
 #include "snpnet.h"
 #include "nii.h"
 
@@ -37,53 +34,6 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
  *
  */
 
-/**
- * Check to see if driver supports a device
- *
- * @v device		EFI device handle
- * @v protocol		Protocol GUID
- * @ret rc		Return status code
- */
-static int snp_nii_supported ( EFI_HANDLE device, EFI_GUID *protocol ) {
-	EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
-	EFI_HANDLE parent;
-	EFI_STATUS efirc;
-	int rc;
-
-	/* Check that this is not a device we are providing ourselves */
-	if ( find_snpdev ( device ) != NULL ) {
-		DBGCP ( device, "HANDLE %s is provided by this binary\n",
-			efi_handle_name ( device ) );
-		return -ENOTTY;
-	}
-
-	/* Test for presence of protocol */
-	if ( ( efirc = bs->OpenProtocol ( device, protocol,
-					  NULL, efi_image_handle, device,
-					  EFI_OPEN_PROTOCOL_TEST_PROTOCOL))!=0){
-		DBGCP ( device, "HANDLE %s is not a %s device\n",
-			efi_handle_name ( device ),
-			efi_guid_ntoa ( protocol ) );
-		return -EEFI ( efirc );
-	}
-
-	/* Check that there are no instances of this protocol further
-	 * up this device path.
-	 */
-	if ( ( rc = efi_locate_device ( device, protocol,
-					&parent, 1 ) ) == 0 ) {
-		DBGC2 ( device, "HANDLE %s has %s-supporting parent ",
-			efi_handle_name ( device ),
-			efi_guid_ntoa ( protocol ) );
-		DBGC2 ( device, "%s\n", efi_handle_name ( parent ) );
-		return -ENOTTY;
-	}
-
-	DBGC ( device, "HANDLE %s is a %s device\n",
-	       efi_handle_name ( device ), efi_guid_ntoa ( protocol ) );
-	return 0;
-}
-
 /**
  * Check to see if driver supports a device
  *
@@ -92,7 +42,7 @@ static int snp_nii_supported ( EFI_HANDLE device, EFI_GUID *protocol ) {
  */
 static int snp_supported ( EFI_HANDLE device ) {
 
-	return snp_nii_supported ( device, &efi_simple_network_protocol_guid );
+	return snpnet_supported ( device, &efi_simple_network_protocol_guid );
 }
 
 /**
@@ -103,7 +53,7 @@ static int snp_supported ( EFI_HANDLE device ) {
  */
 static int nii_supported ( EFI_HANDLE device ) {
 
-	return snp_nii_supported ( device, &efi_nii31_protocol_guid );
+	return snpnet_supported ( device, &efi_nii31_protocol_guid );
 }
 
 /** EFI SNP driver */
-- 
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