efi_loader: implement MCastIPtoMAC

Implement the MCastIPtoMAC service of the simple network protocol.
It converts an multicast IPv4 (or IPv6) address to a multicast Ethernet
address.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>

diff --git a/lib/efi_loader/efi_net.c b/lib/efi_loader/efi_net.c
index 66c1898940fce92e881a15ce026e820cd834b373..cff6332a68654c9d031042539d225eee8eef4799 100644 (file)
--- a/lib/efi_loader/efi_net.c
+++ b/lib/efi_loader/efi_net.c
@@ -332,7 +332,7 @@ static efi_status_t EFIAPI efi_net_statistics(struct efi_simple_network *this,
 /*
  * efi_net_mcastiptomac() - translate multicast IP address to MAC address
  *
- * This function implements the Statistics service of the
+ * This function implements the MCastIPtoMAC service of the
  * EFI_SIMPLE_NETWORK_PROTOCOL. See the Unified Extensible Firmware Interface
  * (UEFI) specification for details.
  *
@@ -347,9 +347,49 @@ static efi_status_t EFIAPI efi_net_mcastiptomac(struct efi_simple_network *this,
                                                struct efi_ip_address *ip,
                                                struct efi_mac_address *mac)
 {
+       efi_status_t ret = EFI_SUCCESS;
+
        EFI_ENTRY("%p, %x, %p, %p", this, ipv6, ip, mac);
 
-       return EFI_EXIT(EFI_INVALID_PARAMETER);
+       if (!this || !ip || !mac) {
+               ret = EFI_INVALID_PARAMETER;
+               goto out;
+       }
+
+       if (ipv6) {
+               ret = EFI_UNSUPPORTED;
+               goto out;
+       }
+
+       /* Multi-cast addresses are in the range 224.0.0.0 - 239.255.255.255 */
+       if ((ip->ip_addr[0] & 0xf0) != 0xe0) {
+               ret = EFI_INVALID_PARAMETER;
+               goto out;
+       };
+
+       switch (this->mode->state) {
+       case EFI_NETWORK_INITIALIZED:
+       case EFI_NETWORK_STARTED:
+               break;
+       default:
+               ret = EFI_NOT_STARTED;
+               goto out;
+       }
+
+       memset(mac, 0, sizeof(struct efi_mac_address));
+
+       /*
+        * Copy lower 23 bits of IPv4 multi-cast address
+        * RFC 1112, RFC 7042 2.1.1.
+        */
+       mac->mac_addr[0] = 0x01;
+       mac->mac_addr[1] = 0x00;
+       mac->mac_addr[2] = 0x5E;
+       mac->mac_addr[3] = ip->ip_addr[1] & 0x7F;
+       mac->mac_addr[4] = ip->ip_addr[2];
+       mac->mac_addr[5] = ip->ip_addr[3];
+out:
+       return EFI_EXIT(ret);
 }
 
 /**