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net/ethernet: Fix VLAN networking on little-endian systems

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VLAN configuration seems to have never worked on little-endian systems.
This is likely because VLANTAG_IDENTIFIER is not byte-swapped before
copying into the net buffer, nor is inf->vlantag. We can resolve this by
using grub_cpu_to_be16{_compile_time}() and its inverse when copying
VLAN info to/from the net buffer.

Signed-off-by: Chad Kimes <chkimes@github.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This commit is contained in:
Chad Kimes 2022-03-02 14:21:22 -05:00 committed by Daniel Kiper
parent 8b7a0e262a
commit c216df4036
1 changed files with 5 additions and 4 deletions
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9
grub-core/net/ethernet.c
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@ -58,7 +58,7 @@ send_ethernet_packet (struct grub_net_network_level_interface *inf,
struct etherhdr *eth;
grub_err_t err;
grub_uint8_t etherhdr_size;
grub_uint16_t vlantag_id = VLANTAG_IDENTIFIER;
grub_uint16_t vlantag_id = grub_cpu_to_be16_compile_time (VLANTAG_IDENTIFIER);
etherhdr_size = sizeof (*eth);
COMPILE_TIME_ASSERT (sizeof (*eth) + 4 < GRUB_NET_MAX_LINK_HEADER_SIZE);
@ -93,8 +93,9 @@ send_ethernet_packet (struct grub_net_network_level_interface *inf,
(char *) nb->data + etherhdr_size - 6, 2);
/* Add the tag in the middle */
grub_uint16_t vlan = grub_cpu_to_be16 (inf->vlantag);
grub_memcpy ((char *) nb->data + etherhdr_size - 6, &vlantag_id, 2);
grub_memcpy ((char *) nb->data + etherhdr_size - 4, (char *) &(inf->vlantag), 2);
grub_memcpy ((char *) nb->data + etherhdr_size - 4, &vlan, 2);
}
return inf->card->driver->send (inf->card, nb);
@ -118,9 +119,9 @@ grub_net_recv_ethernet_packet (struct grub_net_buff *nb,
/* 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)
if (grub_get_unaligned16 (nb->data + etherhdr_size - 2) == grub_cpu_to_be16_compile_time (VLANTAG_IDENTIFIER))
{
vlantag = grub_get_unaligned16 (nb->data + etherhdr_size);
vlantag = grub_be_to_cpu16 (grub_get_unaligned16 (nb->data + etherhdr_size));
etherhdr_size += 4;
/* Move eth type to the original position */
grub_memcpy((char *) nb->data + etherhdr_size - 6,