From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Andrzej Kacprowski <andrzej.kacprowski@intel.com>
Date: Fri, 21 Apr 2017 10:06:20 +0200
Subject: [PATCH] Add support for non-Ethernet network cards

This patch replaces fixed 6-byte link layer address with
up to 32-byte variable sized address.
This allows supporting Infiniband and Omni-Path fabric
which use 20-byte address, but other network card types
can also take advantage of this change.
The network card driver is responsible for replacing L2
header provided by grub2 if needed.
This approach is compatible with UEFI network stack which
also allows up to 32-byte variable size link address.

The BOOTP/DHCP packet format is limited to 16 byte client
hardware address, if link address is more that 16-bytes
then chaddr field in BOOTP it will be set to 0 as per rfc4390.

Resolves: rhbz#1370642

Signed-off-by: Andrzej Kacprowski <andrzej.kacprowski@intel.com>

Conflicts:
	grub-core/net/ip.c
---
 grub-core/net/arp.c                    | 155 ++++++++++++++++++++++-----------
 grub-core/net/bootp.c                  |  14 ++-
 grub-core/net/drivers/efi/efinet.c     |   8 +-
 grub-core/net/drivers/emu/emunet.c     |   1 +
 grub-core/net/drivers/i386/pc/pxe.c    |  13 +--
 grub-core/net/drivers/ieee1275/ofnet.c |   2 +
 grub-core/net/drivers/uboot/ubootnet.c |   1 +
 grub-core/net/ethernet.c               |  88 +++++++++----------
 grub-core/net/icmp6.c                  |  15 ++--
 grub-core/net/ip.c                     |   4 +-
 grub-core/net/net.c                    |  48 +++++-----
 include/grub/net.h                     |  19 ++--
 12 files changed, 216 insertions(+), 152 deletions(-)

diff --git a/grub-core/net/arp.c b/grub-core/net/arp.c
index 54306e3b1..67b409a8a 100644
--- a/grub-core/net/arp.c
+++ b/grub-core/net/arp.c
@@ -31,22 +31,12 @@ enum
     ARP_REPLY = 2
   };
 
-enum
-  {
-    /* IANA ARP constant to define hardware type as ethernet. */
-    GRUB_NET_ARPHRD_ETHERNET = 1
-  };
-
-struct arppkt {
+struct arphdr {
   grub_uint16_t hrd;
   grub_uint16_t pro;
   grub_uint8_t hln;
   grub_uint8_t pln;
   grub_uint16_t op;
-  grub_uint8_t sender_mac[6];
-  grub_uint32_t sender_ip;
-  grub_uint8_t recv_mac[6];
-  grub_uint32_t recv_ip;
 } GRUB_PACKED;
 
 static int have_pending;
@@ -57,12 +47,16 @@ grub_net_arp_send_request (struct grub_net_network_level_interface *inf,
 			   const grub_net_network_level_address_t *proto_addr)
 {
   struct grub_net_buff nb;
-  struct arppkt *arp_packet;
+  struct arphdr *arp_header;
   grub_net_link_level_address_t target_mac_addr;
   grub_err_t err;
   int i;
   grub_uint8_t *nbd;
   grub_uint8_t arp_data[128];
+  grub_uint8_t hln;
+  grub_uint8_t pln;
+  grub_uint8_t arp_packet_len;
+  grub_uint8_t *tmp_ptr;
 
   if (proto_addr->type != GRUB_NET_NETWORK_LEVEL_PROTOCOL_IPV4)
     return grub_error (GRUB_ERR_BUG, "unsupported address family");
@@ -73,23 +67,39 @@ grub_net_arp_send_request (struct grub_net_network_level_interface *inf,
   grub_netbuff_clear (&nb);
   grub_netbuff_reserve (&nb, 128);
 
-  err = grub_netbuff_push (&nb, sizeof (*arp_packet));
+  hln = inf->card->default_address.len;
+  pln = sizeof (proto_addr->ipv4);
+  arp_packet_len = sizeof (*arp_header) + 2 * (hln + pln);
+
+  err = grub_netbuff_push (&nb, arp_packet_len);
   if (err)
     return err;
 
-  arp_packet = (struct arppkt *) nb.data;
-  arp_packet->hrd = grub_cpu_to_be16_compile_time (GRUB_NET_ARPHRD_ETHERNET);
-  arp_packet->hln = 6;
-  arp_packet->pro = grub_cpu_to_be16_compile_time (GRUB_NET_ETHERTYPE_IP);
-  arp_packet->pln = 4;
-  arp_packet->op = grub_cpu_to_be16_compile_time (ARP_REQUEST);
-  /* Sender hardware address.  */
-  grub_memcpy (arp_packet->sender_mac, &inf->hwaddress.mac, 6);
-  arp_packet->sender_ip = inf->address.ipv4;
-  grub_memset (arp_packet->recv_mac, 0, 6);
-  arp_packet->recv_ip = proto_addr->ipv4;
-  /* Target protocol address */
-  grub_memset (&target_mac_addr.mac, 0xff, 6);
+  arp_header = (struct arphdr *) nb.data;
+  arp_header->hrd = grub_cpu_to_be16 (inf->card->default_address.type);
+  arp_header->hln = hln;
+  arp_header->pro = grub_cpu_to_be16_compile_time (GRUB_NET_ETHERTYPE_IP);
+  arp_header->pln = pln;
+  arp_header->op = grub_cpu_to_be16_compile_time (ARP_REQUEST);
+  tmp_ptr = nb.data + sizeof (*arp_header);
+
+  /* The source hardware address. */
+  grub_memcpy (tmp_ptr, inf->hwaddress.mac, hln);
+  tmp_ptr += hln;
+
+  /* The source protocol address. */
+  grub_memcpy (tmp_ptr, &inf->address.ipv4, pln);
+  tmp_ptr += pln;
+
+  /* The target hardware address. */
+  grub_memset (tmp_ptr, 0, hln);
+  tmp_ptr += hln;
+
+  /* The target protocol address */
+  grub_memcpy (tmp_ptr, &proto_addr->ipv4, pln);
+  tmp_ptr += pln;
+
+  grub_memset (&target_mac_addr.mac, 0xff, hln);
 
   nbd = nb.data;
   send_ethernet_packet (inf, &nb, target_mac_addr, GRUB_NET_ETHERTYPE_ARP);
@@ -114,28 +124,53 @@ grub_err_t
 grub_net_arp_receive (struct grub_net_buff *nb, struct grub_net_card *card,
                       grub_uint16_t *vlantag)
 {
-  struct arppkt *arp_packet = (struct arppkt *) nb->data;
+  struct arphdr *arp_header = (struct arphdr *) nb->data;
   grub_net_network_level_address_t sender_addr, target_addr;
   grub_net_link_level_address_t sender_mac_addr;
   struct grub_net_network_level_interface *inf;
+  grub_uint16_t hw_type;
+  grub_uint8_t hln;
+  grub_uint8_t pln;
+  grub_uint8_t arp_packet_len;
+  grub_uint8_t *tmp_ptr;
 
-  if (arp_packet->pro != grub_cpu_to_be16_compile_time (GRUB_NET_ETHERTYPE_IP)
-      || arp_packet->pln != 4 || arp_packet->hln != 6
-      || nb->tail - nb->data < (int) sizeof (*arp_packet))
+  hw_type = card->default_address.type;
+  hln = card->default_address.len;
+  pln = sizeof(sender_addr.ipv4);
+  arp_packet_len = sizeof (*arp_header) + 2 * (pln + hln);
+
+  if (arp_header->pro != grub_cpu_to_be16_compile_time (GRUB_NET_ETHERTYPE_IP)
+      || arp_header->hrd != grub_cpu_to_be16 (hw_type)
+      || arp_header->hln != hln || arp_header->pln != pln
+      || nb->tail - nb->data < (int) arp_packet_len) {
     return GRUB_ERR_NONE;
+  }
 
+  tmp_ptr =  nb->data + sizeof (*arp_header);
+
+  /* The source hardware address. */
+  sender_mac_addr.type = hw_type;
+  sender_mac_addr.len = hln;
+  grub_memcpy (sender_mac_addr.mac, tmp_ptr, hln);
+  tmp_ptr += hln;
+
+  /* The source protocol address. */
   sender_addr.type = GRUB_NET_NETWORK_LEVEL_PROTOCOL_IPV4;
+  grub_memcpy(&sender_addr.ipv4, tmp_ptr, pln);
+  tmp_ptr += pln;
+
+  grub_net_link_layer_add_address (card, &sender_addr, &sender_mac_addr, 1);
+
+  /* The target hardware address. */
+  tmp_ptr += hln;
+
+  /* The target protocol address. */
   target_addr.type = GRUB_NET_NETWORK_LEVEL_PROTOCOL_IPV4;
-  sender_addr.ipv4 = arp_packet->sender_ip;
-  target_addr.ipv4 = arp_packet->recv_ip;
-  if (arp_packet->sender_ip == pending_req)
+  grub_memcpy(&target_addr.ipv4, tmp_ptr, pln);
+
+  if (sender_addr.ipv4 == pending_req)
     have_pending = 1;
 
-  sender_mac_addr.type = GRUB_NET_LINK_LEVEL_PROTOCOL_ETHERNET;
-  grub_memcpy (sender_mac_addr.mac, arp_packet->sender_mac,
-	       sizeof (sender_mac_addr.mac));
-  grub_net_link_layer_add_address (card, &sender_addr, &sender_mac_addr, 1);
-
   FOR_NET_NETWORK_LEVEL_INTERFACES (inf)
   {
     /* Verify vlantag id */
@@ -148,11 +183,11 @@ grub_net_arp_receive (struct grub_net_buff *nb, struct grub_net_card *card,
 
     /* Am I the protocol address target? */
     if (grub_net_addr_cmp (&inf->address, &target_addr) == 0
-	&& arp_packet->op == grub_cpu_to_be16_compile_time (ARP_REQUEST))
+	&& arp_header->op == grub_cpu_to_be16_compile_time (ARP_REQUEST))
       {
 	grub_net_link_level_address_t target;
 	struct grub_net_buff nb_reply;
-	struct arppkt *arp_reply;
+	struct arphdr *arp_reply;
 	grub_uint8_t arp_data[128];
 	grub_err_t err;
 
@@ -161,25 +196,39 @@ grub_net_arp_receive (struct grub_net_buff *nb, struct grub_net_card *card,
 	grub_netbuff_clear (&nb_reply);
 	grub_netbuff_reserve (&nb_reply, 128);
 
-	err = grub_netbuff_push (&nb_reply, sizeof (*arp_packet));
+	err = grub_netbuff_push (&nb_reply, arp_packet_len);
 	if (err)
 	  return err;
 
-	arp_reply = (struct arppkt *) nb_reply.data;
+	arp_reply = (struct arphdr *) nb_reply.data;
 
-	arp_reply->hrd = grub_cpu_to_be16_compile_time (GRUB_NET_ARPHRD_ETHERNET);
+	arp_reply->hrd = grub_cpu_to_be16 (hw_type);
 	arp_reply->pro = grub_cpu_to_be16_compile_time (GRUB_NET_ETHERTYPE_IP);
-	arp_reply->pln = 4;
-	arp_reply->hln = 6;
+	arp_reply->pln = pln;
+	arp_reply->hln = hln;
 	arp_reply->op = grub_cpu_to_be16_compile_time (ARP_REPLY);
-	arp_reply->sender_ip = arp_packet->recv_ip;
-	arp_reply->recv_ip = arp_packet->sender_ip;
-	arp_reply->hln = 6;
-
-	target.type = GRUB_NET_LINK_LEVEL_PROTOCOL_ETHERNET;
-	grub_memcpy (target.mac, arp_packet->sender_mac, 6);
-	grub_memcpy (arp_reply->sender_mac, inf->hwaddress.mac, 6);
-	grub_memcpy (arp_reply->recv_mac, arp_packet->sender_mac, 6);
+
+	tmp_ptr = nb_reply.data + sizeof (*arp_reply);
+
+	/* The source hardware address. */
+	grub_memcpy (tmp_ptr, inf->hwaddress.mac, hln);
+	tmp_ptr += hln;
+
+	/* The source protocol address. */
+	grub_memcpy (tmp_ptr, &target_addr.ipv4, pln);
+	tmp_ptr += pln;
+
+	/* The target hardware address. */
+	grub_memcpy (tmp_ptr, sender_mac_addr.mac, hln);
+	tmp_ptr += hln;
+
+	/* The target protocol address */
+	grub_memcpy (tmp_ptr, &sender_addr.ipv4, pln);
+	tmp_ptr += pln;
+
+	target.type = hw_type;
+	target.len = hln;
+	grub_memcpy (target.mac, sender_mac_addr.mac, hln);
 
 	/* Change operation to REPLY and send packet */
 	send_ethernet_packet (inf, &nb_reply, target, GRUB_NET_ETHERTYPE_ARP);
diff --git a/grub-core/net/bootp.c b/grub-core/net/bootp.c
index 2869482fe..4e55adc55 100644
--- a/grub-core/net/bootp.c
+++ b/grub-core/net/bootp.c
@@ -219,7 +219,6 @@ grub_net_configure_by_dhcp_ack (const char *name,
 				int is_def, char **device, char **path)
 {
   grub_net_network_level_address_t addr;
-  grub_net_link_level_address_t hwaddr;
   struct grub_net_network_level_interface *inter;
   int mask = -1;
   char server_ip[sizeof ("xxx.xxx.xxx.xxx")];
@@ -232,12 +231,8 @@ grub_net_configure_by_dhcp_ack (const char *name,
   if (path)
     *path = 0;
 
-  grub_memcpy (hwaddr.mac, bp->mac_addr,
-	       bp->hw_len < sizeof (hwaddr.mac) ? bp->hw_len
-	       : sizeof (hwaddr.mac));
-  hwaddr.type = GRUB_NET_LINK_LEVEL_PROTOCOL_ETHERNET;
-
-  inter = grub_net_add_addr (name, card, &addr, &hwaddr, flags);
+  grub_dprintf("dhcp", "configuring dhcp for %s\n", name);
+  inter = grub_net_add_addr (name, card, &addr, &card->default_address, flags);
   if (!inter)
     return 0;
 
@@ -770,7 +765,8 @@ grub_cmd_bootp (struct grub_command *cmd __attribute__ ((unused)),
 	  grub_memset (pack, 0, sizeof (*pack) + 64);
 	  pack->opcode = 1;
 	  pack->hw_type = 1;
-	  pack->hw_len = 6;
+	  pack->hw_len = ifaces[j].hwaddress.len > 16 ? 0
+						      : ifaces[j].hwaddress.len;
 	  err = grub_get_datetime (&date);
 	  if (err || !grub_datetime2unixtime (&date, &t))
 	    {
@@ -781,7 +777,7 @@ grub_cmd_bootp (struct grub_command *cmd __attribute__ ((unused)),
 	  ifaces[j].dhcp_xid = pack->xid;
 	  pack->seconds = grub_cpu_to_be16 (t);
 
-	  grub_memcpy (&pack->mac_addr, &ifaces[j].hwaddress.mac, 6); 
+	  grub_memcpy (&pack->mac_addr, &ifaces[j].hwaddress.mac, pack->hw_len);
 
 	  grub_netbuff_push (nb, sizeof (*udph));
 
diff --git a/grub-core/net/drivers/efi/efinet.c b/grub-core/net/drivers/efi/efinet.c
index a4daaa460..cd6dba79f 100644
--- a/grub-core/net/drivers/efi/efinet.c
+++ b/grub-core/net/drivers/efi/efinet.c
@@ -280,6 +280,9 @@ grub_efinet_findcards (void)
 	/* This should not happen... Why?  */
 	continue;
 
+      if (net->mode->hwaddr_size > GRUB_NET_MAX_LINK_ADDRESS_SIZE)
+	continue;
+
       if (net->mode->state == GRUB_EFI_NETWORK_STOPPED
 	  && efi_call_1 (net->start, net) != GRUB_EFI_SUCCESS)
 	continue;
@@ -316,10 +319,11 @@ grub_efinet_findcards (void)
       card->name = grub_xasprintf ("efinet%d", i++);
       card->driver = &efidriver;
       card->flags = 0;
-      card->default_address.type = GRUB_NET_LINK_LEVEL_PROTOCOL_ETHERNET;
+      card->default_address.type = net->mode->if_type;
+      card->default_address.len = net->mode->hwaddr_size;
       grub_memcpy (card->default_address.mac,
 		   net->mode->current_address,
-		   sizeof (card->default_address.mac));
+		   net->mode->hwaddr_size);
       card->efi_net = net;
       card->efi_handle = *handle;
 
diff --git a/grub-core/net/drivers/emu/emunet.c b/grub-core/net/drivers/emu/emunet.c
index b19492086..5b6c5e16a 100644
--- a/grub-core/net/drivers/emu/emunet.c
+++ b/grub-core/net/drivers/emu/emunet.c
@@ -46,6 +46,7 @@ static struct grub_net_card emucard =
     .mtu = 1500,
     .default_address = {
 			 .type = GRUB_NET_LINK_LEVEL_PROTOCOL_ETHERNET,
+			 . len = 6,
 			 {.mac = {0, 1, 2, 3, 4, 5}}
 		       },
     .flags = 0
diff --git a/grub-core/net/drivers/i386/pc/pxe.c b/grub-core/net/drivers/i386/pc/pxe.c
index 3f4152d03..9f8fb4b6d 100644
--- a/grub-core/net/drivers/i386/pc/pxe.c
+++ b/grub-core/net/drivers/i386/pc/pxe.c
@@ -386,20 +386,21 @@ GRUB_MOD_INIT(pxe)
   grub_memset (ui, 0, sizeof (*ui));
   grub_pxe_call (GRUB_PXENV_UNDI_GET_INFORMATION, ui, pxe_rm_entry);
 
+  grub_pxe_card.default_address.len = 6;
   grub_memcpy (grub_pxe_card.default_address.mac, ui->current_addr,
-	       sizeof (grub_pxe_card.default_address.mac));
-  for (i = 0; i < sizeof (grub_pxe_card.default_address.mac); i++)
+	       grub_pxe_card.default_address.len);
+  for (i = 0; i < grub_pxe_card.default_address.len; i++)
     if (grub_pxe_card.default_address.mac[i] != 0)
       break;
-  if (i != sizeof (grub_pxe_card.default_address.mac))
+  if (i != grub_pxe_card.default_address.len)
     {
-      for (i = 0; i < sizeof (grub_pxe_card.default_address.mac); i++)
+      for (i = 0; i < grub_pxe_card.default_address.len; i++)
 	if (grub_pxe_card.default_address.mac[i] != 0xff)
 	  break;
     }
-  if (i == sizeof (grub_pxe_card.default_address.mac))
+  if (i == grub_pxe_card.default_address.len)
     grub_memcpy (grub_pxe_card.default_address.mac, ui->permanent_addr,
-		 sizeof (grub_pxe_card.default_address.mac));
+		 grub_pxe_card.default_address.len);
   grub_pxe_card.mtu = ui->mtu;
 
   grub_pxe_card.default_address.type = GRUB_NET_LINK_LEVEL_PROTOCOL_ETHERNET;
diff --git a/grub-core/net/drivers/ieee1275/ofnet.c b/grub-core/net/drivers/ieee1275/ofnet.c
index 3df75357a..ba50415f5 100644
--- a/grub-core/net/drivers/ieee1275/ofnet.c
+++ b/grub-core/net/drivers/ieee1275/ofnet.c
@@ -160,6 +160,7 @@ grub_ieee1275_parse_bootpath (const char *devpath, char *bootpath,
   grub_uint16_t vlantag = 0;
 
   hw_addr.type = GRUB_NET_LINK_LEVEL_PROTOCOL_ETHERNET;
+  hw_addr.len = 6;
 
   args = bootpath + grub_strlen (devpath) + 1;
   do
@@ -503,6 +504,7 @@ search_net_devices (struct grub_ieee1275_devalias *alias)
     grub_memcpy (&lla.mac, pprop, 6);
 
   lla.type = GRUB_NET_LINK_LEVEL_PROTOCOL_ETHERNET;
+  lla.len = 6;
   card->default_address = lla;
 
   card->txbufsize = ALIGN_UP (card->mtu, 64) + 256;
diff --git a/grub-core/net/drivers/uboot/ubootnet.c b/grub-core/net/drivers/uboot/ubootnet.c
index 056052e40..22ebcbf21 100644
--- a/grub-core/net/drivers/uboot/ubootnet.c
+++ b/grub-core/net/drivers/uboot/ubootnet.c
@@ -131,6 +131,7 @@ GRUB_MOD_INIT (ubootnet)
 
       grub_memcpy (&(card->default_address.mac), &devinfo->di_net.hwaddr, 6);
       card->default_address.type = GRUB_NET_LINK_LEVEL_PROTOCOL_ETHERNET;
+      card->default_address.len = 6;
 
       card->txbufsize = ALIGN_UP (card->mtu, 64) + 256;
       card->txbuf = grub_zalloc (card->txbufsize);
diff --git a/grub-core/net/ethernet.c b/grub-core/net/ethernet.c
index 4d7ceed6f..9aae83a5e 100644
--- a/grub-core/net/ethernet.c
+++ b/grub-core/net/ethernet.c
@@ -29,13 +29,6 @@
 
 #define LLCADDRMASK 0x7f
 
-struct etherhdr
-{
-  grub_uint8_t dst[6];
-  grub_uint8_t src[6];
-  grub_uint16_t type;
-} GRUB_PACKED;
-
 struct llchdr
 {
   grub_uint8_t dsap;
@@ -55,13 +48,15 @@ send_ethernet_packet (struct grub_net_network_level_interface *inf,
 		      grub_net_link_level_address_t target_addr,
 		      grub_net_ethertype_t ethertype)
 {
-  struct etherhdr *eth;
+  grub_uint8_t *eth;
   grub_err_t err;
-  grub_uint8_t etherhdr_size;
-  grub_uint16_t vlantag_id = VLANTAG_IDENTIFIER;
+  grub_uint32_t vlantag = 0;
+  grub_uint8_t hw_addr_len = inf->card->default_address.len;
+  grub_uint8_t etherhdr_size = 2 * hw_addr_len + 2;
 
-  etherhdr_size = sizeof (*eth);
-  COMPILE_TIME_ASSERT (sizeof (*eth) + 4 < GRUB_NET_MAX_LINK_HEADER_SIZE);
+  /* Source and destination link addresses + ethertype + vlan tag */
+  COMPILE_TIME_ASSERT ((GRUB_NET_MAX_LINK_ADDRESS_SIZE * 2 + 2 + 4) <
+		       GRUB_NET_MAX_LINK_HEADER_SIZE);
 
   /* Increase ethernet header in case of vlantag */
   if (inf->vlantag != 0)
@@ -70,11 +65,22 @@ send_ethernet_packet (struct grub_net_network_level_interface *inf,
   err = grub_netbuff_push (nb, etherhdr_size);
   if (err)
     return err;
-  eth = (struct etherhdr *) nb->data;
-  grub_memcpy (eth->dst, target_addr.mac, 6);
-  grub_memcpy (eth->src, inf->hwaddress.mac, 6);
+  eth = nb->data;
+  grub_memcpy (eth, target_addr.mac, hw_addr_len);
+  eth += hw_addr_len;
+  grub_memcpy (eth, inf->hwaddress.mac, hw_addr_len);
+  eth += hw_addr_len;
+
+  /* Check if a vlan-tag is present. */
+  if (vlantag != 0)
+    {
+      *((grub_uint32_t *)eth) = grub_cpu_to_be32 (vlantag);
+      eth += sizeof (vlantag);
+    }
+
+  /* Write ethertype */
+  *((grub_uint16_t*) eth) = grub_cpu_to_be16 (ethertype);
 
-  eth->type = grub_cpu_to_be16 (ethertype);
   if (!inf->card->opened)
     {
       err = GRUB_ERR_NONE;
@@ -85,18 +91,6 @@ send_ethernet_packet (struct grub_net_network_level_interface *inf,
       inf->card->opened = 1;
     }
 
-  /* Check and add a vlan-tag if needed. */
-  if (inf->vlantag != 0)
-    {
-      /* Move eth type to the right */
-      grub_memcpy ((char *) nb->data + etherhdr_size - 2,
-                   (char *) nb->data + etherhdr_size - 6, 2);
-
-      /* Add the tag in the middle */
-      grub_memcpy ((char *) nb->data + etherhdr_size - 6, &vlantag_id, 2);
-      grub_memcpy ((char *) nb->data + etherhdr_size - 4, (char *) &(inf->vlantag), 2);
-    }
-
   return inf->card->driver->send (inf->card, nb);
 }
 
@@ -104,31 +98,40 @@ grub_err_t
 grub_net_recv_ethernet_packet (struct grub_net_buff *nb,
 			       struct grub_net_card *card)
 {
-  struct etherhdr *eth;
+  grub_uint8_t *eth;
   struct llchdr *llch;
   struct snaphdr *snaph;
   grub_net_ethertype_t type;
   grub_net_link_level_address_t hwaddress;
   grub_net_link_level_address_t src_hwaddress;
   grub_err_t err;
-  grub_uint8_t etherhdr_size = sizeof (*eth);
+  grub_uint8_t hw_addr_len = card->default_address.len;
+  grub_uint8_t etherhdr_size = 2 * hw_addr_len + 2;
   grub_uint16_t vlantag = 0;
 
+  eth = nb->data;
 
-  /* Check if a vlan-tag is present. If so, the ethernet header is 4 bytes */
-  /* longer than the original one. The vlantag id is extracted and the header */
-  /* is reseted to the original size. */
-  if (grub_get_unaligned16 (nb->data + etherhdr_size - 2) == VLANTAG_IDENTIFIER)
+  hwaddress.type = card->default_address.type;
+  hwaddress.len = hw_addr_len;
+  grub_memcpy (hwaddress.mac, eth, hw_addr_len);
+  eth += hw_addr_len;
+
+  src_hwaddress.type = card->default_address.type;
+  src_hwaddress.len = hw_addr_len;
+  grub_memcpy (src_hwaddress.mac, eth, hw_addr_len);
+  eth += hw_addr_len;
+
+  type = grub_be_to_cpu16 (*(grub_uint16_t*)(eth));
+  if (type == VLANTAG_IDENTIFIER)
     {
-      vlantag = grub_get_unaligned16 (nb->data + etherhdr_size);
+      /* Skip vlan tag */
+      eth += 2;
+      vlantag = grub_be_to_cpu16 (*(grub_uint16_t*)(eth));
       etherhdr_size += 4;
-      /* Move eth type to the original position */
-      grub_memcpy((char *) nb->data + etherhdr_size - 6,
-                  (char *) nb->data + etherhdr_size - 2, 2);
+      eth += 2;
+      type = grub_be_to_cpu16 (*(grub_uint16_t*)(eth));
     }
 
-  eth = (struct etherhdr *) nb->data;
-  type = grub_be_to_cpu16 (eth->type);
   err = grub_netbuff_pull (nb, etherhdr_size);
   if (err)
     return err;
@@ -148,11 +151,6 @@ grub_net_recv_ethernet_packet (struct grub_net_buff *nb,
 	}
     }
 
-  hwaddress.type = GRUB_NET_LINK_LEVEL_PROTOCOL_ETHERNET;
-  grub_memcpy (hwaddress.mac, eth->dst, sizeof (hwaddress.mac));
-  src_hwaddress.type = GRUB_NET_LINK_LEVEL_PROTOCOL_ETHERNET;
-  grub_memcpy (src_hwaddress.mac, eth->src, sizeof (src_hwaddress.mac));
-
   switch (type)
     {
       /* ARP packet. */
diff --git a/grub-core/net/icmp6.c b/grub-core/net/icmp6.c
index 2cbd95dce..56a3ec5c8 100644
--- a/grub-core/net/icmp6.c
+++ b/grub-core/net/icmp6.c
@@ -231,8 +231,9 @@ grub_net_recv_icmp6_packet (struct grub_net_buff *nb,
 		&& ohdr->len == 1)
 	      {
 		grub_net_link_level_address_t ll_address;
-		ll_address.type = GRUB_NET_LINK_LEVEL_PROTOCOL_ETHERNET;
-		grub_memcpy (ll_address.mac, ohdr + 1, sizeof (ll_address.mac));
+		ll_address.type = card->default_address.type;
+		ll_address.len = card->default_address.len;
+		grub_memcpy (ll_address.mac, ohdr + 1, ll_address.len);
 		grub_net_link_layer_add_address (card, source, &ll_address, 0);
 	      }
 	  }
@@ -335,8 +336,9 @@ grub_net_recv_icmp6_packet (struct grub_net_buff *nb,
 		&& ohdr->len == 1)
 	      {
 		grub_net_link_level_address_t ll_address;
-		ll_address.type = GRUB_NET_LINK_LEVEL_PROTOCOL_ETHERNET;
-		grub_memcpy (ll_address.mac, ohdr + 1, sizeof (ll_address.mac));
+		ll_address.type = card->default_address.type;
+		ll_address.len = card->default_address.len;
+		grub_memcpy (ll_address.mac, ohdr + 1, ll_address.len);
 		grub_net_link_layer_add_address (card, source, &ll_address, 0);
 	      }
 	  }
@@ -384,8 +386,9 @@ grub_net_recv_icmp6_packet (struct grub_net_buff *nb,
 		&& ohdr->len == 1)
 	      {
 		grub_net_link_level_address_t ll_address;
-		ll_address.type = GRUB_NET_LINK_LEVEL_PROTOCOL_ETHERNET;
-		grub_memcpy (ll_address.mac, ohdr + 1, sizeof (ll_address.mac));
+		ll_address.type = card->default_address.type;
+		ll_address.len = card->default_address.len;
+		grub_memcpy (ll_address.mac, ohdr + 1, ll_address.len);
 		grub_net_link_layer_add_address (card, source, &ll_address, 0);
 	      }
 	    if (ohdr->type == OPTION_PREFIX && ohdr->len == 4)
diff --git a/grub-core/net/ip.c b/grub-core/net/ip.c
index 8411e0ecc..b2ca74b6e 100644
--- a/grub-core/net/ip.c
+++ b/grub-core/net/ip.c
@@ -277,8 +277,8 @@ handle_dgram (struct grub_net_buff *nb,
 	      && inf->address.type == GRUB_NET_NETWORK_LEVEL_PROTOCOL_DHCP_RECV
 	      && inf->dhcp_xid == bootp->xid
 	      && inf->hwaddress.type == GRUB_NET_LINK_LEVEL_PROTOCOL_ETHERNET
-	      && grub_memcmp (inf->hwaddress.mac, &bootp->mac_addr,
-			      sizeof (inf->hwaddress.mac)) == 0)
+	      && (grub_memcmp (inf->hwaddress.mac, &bootp->mac_addr,
+			       bootp->hw_len) == 0 || bootp->hw_len == 0))
 	    {
 	      grub_net_process_dhcp (nb, inf->card);
 	      grub_netbuff_free (nb);
diff --git a/grub-core/net/net.c b/grub-core/net/net.c
index fa3e29126..9b8944292 100644
--- a/grub-core/net/net.c
+++ b/grub-core/net/net.c
@@ -128,8 +128,9 @@ grub_net_link_layer_resolve (struct grub_net_network_level_interface *inf,
 								   << 48)
 	  && proto_addr->ipv6[1] == (grub_be_to_cpu64_compile_time (1))))
     {
-      hw_addr->type = GRUB_NET_LINK_LEVEL_PROTOCOL_ETHERNET;
-      grub_memset (hw_addr->mac, -1, 6);
+      hw_addr->type = inf->card->default_address.type;
+      hw_addr->len = inf->card->default_address.len;
+      grub_memset (hw_addr->mac, -1, hw_addr->len);
       return GRUB_ERR_NONE;
     }
 
@@ -137,6 +138,7 @@ grub_net_link_layer_resolve (struct grub_net_network_level_interface *inf,
       && ((grub_be_to_cpu64 (proto_addr->ipv6[0]) >> 56) == 0xff))
     {
       hw_addr->type = GRUB_NET_LINK_LEVEL_PROTOCOL_ETHERNET;
+      hw_addr->len = inf->card->default_address.len;
       hw_addr->mac[0] = 0x33;
       hw_addr->mac[1] = 0x33;
       hw_addr->mac[2] = ((grub_be_to_cpu64 (proto_addr->ipv6[1]) >> 24) & 0xff);
@@ -757,23 +759,21 @@ grub_net_addr_to_str (const grub_net_network_level_address_t *target, char *buf)
 void
 grub_net_hwaddr_to_str (const grub_net_link_level_address_t *addr, char *str)
 {
-  str[0] = 0;
-  switch (addr->type)
+  char *ptr;
+  unsigned i;
+
+  if (addr->len > GRUB_NET_MAX_LINK_ADDRESS_SIZE)
     {
-    case GRUB_NET_LINK_LEVEL_PROTOCOL_ETHERNET:
-      {
-	char *ptr;
-	unsigned i;
-	for (ptr = str, i = 0; i < ARRAY_SIZE (addr->mac); i++)
-	  {
-	    grub_snprintf (ptr, GRUB_NET_MAX_STR_HWADDR_LEN - (ptr - str),
-			   "%02x:", addr->mac[i] & 0xff);
-	    ptr += (sizeof ("XX:") - 1);
-	  }
-      return;
-      }
+       str[0] = 0;
+       grub_printf (_("Unsupported hw address type %d len %d\n"),
+		    addr->type, addr->len);
+       return;
+    }
+  for (ptr = str, i = 0; i < addr->len; i++)
+    {
+      ptr += grub_snprintf (ptr, GRUB_NET_MAX_STR_HWADDR_LEN - (ptr - str),
+		     "%02x:", addr->mac[i] & 0xff);
     }
-  grub_printf (_("Unsupported hw address type %d\n"), addr->type);
 }
 
 int
@@ -784,13 +784,17 @@ grub_net_hwaddr_cmp (const grub_net_link_level_address_t *a,
     return -1;
   if (a->type > b->type)
     return +1;
-  switch (a->type)
+  if (a->len < b->len)
+    return -1;
+  if (a->len > b->len)
+    return +1;
+  if (a->len > GRUB_NET_MAX_LINK_ADDRESS_SIZE)
     {
-    case GRUB_NET_LINK_LEVEL_PROTOCOL_ETHERNET:
-      return grub_memcmp (a->mac, b->mac, sizeof (a->mac));
+      grub_printf (_("Unsupported hw address type %d len %d\n"),
+		   a->type, a->len);
+      return + 1;
     }
-  grub_printf (_("Unsupported hw address type %d\n"), a->type);
-  return 1;
+  return grub_memcmp (a->mac, b->mac, a->len);
 }
 
 int
diff --git a/include/grub/net.h b/include/grub/net.h
index de51894cb..e9ebc6a1b 100644
--- a/include/grub/net.h
+++ b/include/grub/net.h
@@ -29,7 +29,8 @@
 
 enum
   {
-    GRUB_NET_MAX_LINK_HEADER_SIZE = 64,
+    GRUB_NET_MAX_LINK_HEADER_SIZE = 96,
+    GRUB_NET_MAX_LINK_ADDRESS_SIZE = 32,
     GRUB_NET_UDP_HEADER_SIZE = 8,
     GRUB_NET_TCP_HEADER_SIZE = 20,
     GRUB_NET_OUR_IPV4_HEADER_SIZE = 20,
@@ -42,15 +43,17 @@ enum
 
 typedef enum grub_link_level_protocol_id 
 {
-  GRUB_NET_LINK_LEVEL_PROTOCOL_ETHERNET
+  /* IANA ARP constant to define hardware type. */
+  GRUB_NET_LINK_LEVEL_PROTOCOL_ETHERNET = 1,
 } grub_link_level_protocol_id_t;
 
 typedef struct grub_net_link_level_address
 {
   grub_link_level_protocol_id_t type;
+  grub_uint8_t len;
   union
   {
-    grub_uint8_t mac[6];
+    grub_uint8_t mac[GRUB_NET_MAX_LINK_ADDRESS_SIZE];
   };
 } grub_net_link_level_address_t;
 
@@ -555,11 +558,13 @@ grub_net_addr_cmp (const grub_net_network_level_address_t *a,
 #define GRUB_NET_MAX_STR_ADDR_LEN sizeof ("XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX:XXXX")
 
 /*
-  Currently suppoerted adresses:
-  ethernet:   XX:XX:XX:XX:XX:XX
+  Up to 32 byte hardware address supported, see GRUB_NET_MAX_LINK_ADDRESS_SIZE
  */
-
-#define GRUB_NET_MAX_STR_HWADDR_LEN (sizeof ("XX:XX:XX:XX:XX:XX"))
+#define GRUB_NET_MAX_STR_HWADDR_LEN (sizeof (\
+	"XX:XX:XX:XX:XX:XX:XX:XX:"\
+	"XX:XX:XX:XX:XX:XX:XX:XX:"\
+	"XX:XX:XX:XX:XX:XX:XX:XX:"\
+	"XX:XX:XX:XX:XX:XX:XX:XX"))
 
 void
 grub_net_addr_to_str (const grub_net_network_level_address_t *target,
