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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Peter Jones <pjones@redhat.com>
Date: Fri, 11 Sep 2015 17:30:49 -0400
Subject: [PATCH] Be more aggro about actually using the *configured* network
 device.

Right now we use any SNP device with the same mac+IP block, but when
it's discovered there will be more than one of them.  We need to pick
the same one we were loaded with, so that  it'll be configured the same
way as it was before, and won't be re-used by the system firmware later.

Resolves: rhbz#1257475

Signed-off-by: Peter Jones <example@example.com>
---
 grub-core/net/drivers/efi/efinet.c | 124 +++++++++++++++++++++++++++++--------
 include/grub/efi/api.h             |   4 ++
 2 files changed, 102 insertions(+), 26 deletions(-)

diff --git a/grub-core/net/drivers/efi/efinet.c b/grub-core/net/drivers/efi/efinet.c
index 3f112438a93..a3ce4c67cce 100644
--- a/grub-core/net/drivers/efi/efinet.c
+++ b/grub-core/net/drivers/efi/efinet.c
@@ -239,46 +239,85 @@ grub_efinet_get_device_handle (struct grub_net_card *card)
   return card->efi_handle;
 }
 
-static void
-grub_efinet_findcards (void)
+static int
+grub_efinet_find_snp_cards (int preferred_only, grub_efi_handle_t preferred,
+			    int *i)
 {
-  grub_efi_uintn_t num_handles;
-  grub_efi_handle_t *handles;
+  grub_efi_uintn_t num_handles = 0;
+  grub_efi_handle_t *handles = NULL;
   grub_efi_handle_t *handle;
-  int i = 0;
+  grub_efi_device_path_t *pdp = NULL, *pp = NULL, *pc = NULL;
+  int ret = 0;
 
-  /* Find handles which support the disk io interface.  */
+  if (preferred)
+    {
+      grub_efi_device_path_t *pdpc;
+      pdpc = pdp = grub_efi_get_device_path (preferred);
+      if (pdp == NULL)
+	{
+	  grub_print_error ();
+	  return -1;
+	}
+
+      for (; ! GRUB_EFI_END_ENTIRE_DEVICE_PATH (pdpc);
+	   pdpc = GRUB_EFI_NEXT_DEVICE_PATH (pdpc))
+	{
+	  pp = pc;
+	  pc = pdpc;
+	}
+    }
+
+  /* Find handles which support the SNP interface.  */
   handles = grub_efi_locate_handle (GRUB_EFI_BY_PROTOCOL, &net_io_guid,
 				    0, &num_handles);
-  if (! handles)
-    return;
-  for (handle = handles; num_handles--; handle++)
+
+  for (handle = handles; handle && num_handles--; handle++)
     {
       grub_efi_simple_network_t *net;
       struct grub_net_card *card;
       grub_efi_device_path_t *dp, *parent = NULL, *child = NULL;
 
-      /* EDK2 UEFI PXE driver creates IPv4 and IPv6 messaging devices as
-	 children of main MAC messaging device. We only need one device with
-	 bound SNP per physical card, otherwise they compete with each other
-	 when polling for incoming packets.
-       */
+      /* if we're looking for only the preferred handle, skip anything that
+	 isn't it. */
+      if (preferred_only && preferred != NULL && *handle != preferred)
+	continue;
+
+      /* if we're not looking for the preferred handle, skip it if it's
+	 found. */
+      if (!preferred_only && *handle == preferred)
+	continue;
+
       dp = grub_efi_get_device_path (*handle);
       if (!dp)
 	continue;
-      for (; ! GRUB_EFI_END_ENTIRE_DEVICE_PATH (dp); dp = GRUB_EFI_NEXT_DEVICE_PATH (dp))
+
+      for (; ! GRUB_EFI_END_ENTIRE_DEVICE_PATH (dp);
+	   dp = GRUB_EFI_NEXT_DEVICE_PATH (dp))
 	{
 	  parent = child;
 	  child = dp;
 	}
-      if (child
-	  && GRUB_EFI_DEVICE_PATH_TYPE (child) == GRUB_EFI_MESSAGING_DEVICE_PATH_TYPE
-	  && (GRUB_EFI_DEVICE_PATH_SUBTYPE (child) == GRUB_EFI_IPV4_DEVICE_PATH_SUBTYPE
-	      || GRUB_EFI_DEVICE_PATH_SUBTYPE (child) == GRUB_EFI_IPV6_DEVICE_PATH_SUBTYPE)
-	  && parent
-	  && GRUB_EFI_DEVICE_PATH_TYPE (parent) == GRUB_EFI_MESSAGING_DEVICE_PATH_TYPE
-	  && GRUB_EFI_DEVICE_PATH_SUBTYPE (parent) == GRUB_EFI_MAC_ADDRESS_DEVICE_PATH_SUBTYPE)
-	continue;
+
+      if (!preferred_only)
+	{
+	  if (pp && pc
+	      && grub_efi_compare_device_paths (pp, parent) == 0
+	      && grub_efi_compare_device_paths (pc, child) == 0)
+	    continue;
+
+	  if (child
+	      && (GRUB_EFI_DEVICE_PATH_IS_TYPE(child,
+					  GRUB_EFI_MESSAGING_DEVICE_PATH_TYPE,
+					  GRUB_EFI_IPV6_DEVICE_PATH_SUBTYPE) ||
+		  GRUB_EFI_DEVICE_PATH_IS_TYPE(child,
+					  GRUB_EFI_MESSAGING_DEVICE_PATH_TYPE,
+					  GRUB_EFI_IPV4_DEVICE_PATH_SUBTYPE))
+	      && parent
+	      && (GRUB_EFI_DEVICE_PATH_IS_TYPE(parent,
+				    GRUB_EFI_MESSAGING_DEVICE_PATH_TYPE,
+				    GRUB_EFI_MAC_ADDRESS_DEVICE_PATH_SUBTYPE)))
+	    continue;
+	}
 
       net = grub_efi_open_protocol (*handle, &net_io_guid,
 				    GRUB_EFI_OPEN_PROTOCOL_GET_PROTOCOL);
@@ -302,7 +341,7 @@ grub_efinet_findcards (void)
 	{
 	  grub_print_error ();
 	  grub_free (handles);
-	  return;
+	  return -1;
 	}
 
       card->mtu = net->mode->max_packet_size;
@@ -313,13 +352,14 @@ grub_efinet_findcards (void)
 	  grub_print_error ();
 	  grub_free (handles);
 	  grub_free (card);
-	  return;
+	  return -1;
 	}
       card->txbusy = 0;
 
       card->rcvbufsize = ALIGN_UP (card->mtu, 64) + 256;
 
-      card->name = grub_xasprintf ("efinet%d", i++);
+      card->name = grub_xasprintf ("efinet%d", *i);
+      *i = (*i)+1;
       card->driver = &efidriver;
       card->flags = 0;
       card->default_address.type = GRUB_NET_LINK_LEVEL_PROTOCOL_ETHERNET;
@@ -330,8 +370,38 @@ grub_efinet_findcards (void)
       card->efi_handle = *handle;
 
       grub_net_card_register (card);
+      ret++;
     }
   grub_free (handles);
+
+  return ret;
+}
+
+static void
+grub_efinet_findcards (void)
+{
+  grub_efi_loaded_image_t *image = NULL;
+  int rc;
+  int efinet_number = 0;
+
+  image = grub_efi_get_loaded_image (grub_efi_image_handle);
+
+  if (image && image->device_handle)
+    {
+      rc = grub_efinet_find_snp_cards (1, image->device_handle, &efinet_number);
+      if (rc < 0)
+	return;
+
+      rc = grub_efinet_find_snp_cards (0, image->device_handle, &efinet_number);
+      if (rc < 0)
+	return;
+    }
+  else
+    {
+      rc = grub_efinet_find_snp_cards (0, NULL, &efinet_number);
+      if (rc < 0)
+	return;
+    }
 }
 
 static void
@@ -352,6 +422,8 @@ grub_efi_net_config_real (grub_efi_handle_t hnd, char **device,
     struct grub_efi_pxe_mode *pxe_mode;
     if (card->driver != &efidriver)
       continue;
+    if (hnd != card->efi_handle)
+      continue;
     cdp = grub_efi_get_device_path (card->efi_handle);
     if (! cdp)
       continue;
diff --git a/include/grub/efi/api.h b/include/grub/efi/api.h
index c7c9f0e1db1..97b9aa7a4d7 100644
--- a/include/grub/efi/api.h
+++ b/include/grub/efi/api.h
@@ -622,6 +622,10 @@ typedef struct grub_efi_device_path grub_efi_device_path_t;
    It seems to be identical to EFI_DEVICE_PATH.  */
 typedef struct grub_efi_device_path grub_efi_device_path_protocol_t;
 
+#define GRUB_EFI_DEVICE_PATH_IS_TYPE(dp, type, subtype) \
+	((GRUB_EFI_DEVICE_PATH_TYPE(dp) == (type)) && \
+	 (GRUB_EFI_DEVICE_PATH_SUBTYPE(dp) == (subtype)))
+
 #define GRUB_EFI_DEVICE_PATH_TYPE(dp)		((dp)->type & 0x7f)
 #define GRUB_EFI_DEVICE_PATH_SUBTYPE(dp)	((dp)->subtype)
 #define GRUB_EFI_DEVICE_PATH_LENGTH(dp)		((dp)->length)