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9bootpxe: continues the war against random DHCPv6 DUIDs

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Some UEFI implementations use random UUID based DUID instead of
ethernet address, but use ethernet derived link-local addresses.
So extract the MAC from our IPv6 address.
This commit is contained in:
cinap_lenrek 2020-04-08 23:37:38 +02:00
parent fed50d79d3
commit abc5a66c56
1 changed files with 25 additions and 1 deletions
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26
sys/src/boot/efi/pxe.c
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@ -367,6 +367,7 @@ parsedhcp(EFI_PXE_BASE_CODE_DHCPV4_PACKET *dhcp)
char *x;
int opt;
int len;
uint type;
memset(mymac, 0, sizeof(mymac));
memset(serverip, 0, sizeof(serverip));
@ -389,7 +390,15 @@ parsedhcp(EFI_PXE_BASE_CODE_DHCPV4_PACKET *dhcp)
break;
switch(opt){
case 1: /* Client DUID */
memmove(mymac, p+len-6, 6);
if(len < 4+6)
break;
type = p[0]<<24 | p[1]<<16 | p[2]<<8 | p[3];
switch(type){
case 0x00010001:
case 0x00030001:
memmove(mymac, p+len-6, 6);
break;
}
break;
case 59: /* Boot File URL */
for(x = (char*)p; x < (char*)p+len; x++){
@ -402,6 +411,21 @@ parsedhcp(EFI_PXE_BASE_CODE_DHCPV4_PACKET *dhcp)
}
p += len;
}
/*
* some UEFI implementations use random UUID based DUID instead of
* ethernet address, but use ethernet derived link-local addresses.
* so extract the MAC from our IPv6 address.
*/
if((mymac[0]|mymac[1]|mymac[2]|mymac[3]|mymac[4]|mymac[5]) == 0){
p = pxe->Mode->StationIp;
mymac[0] = p[8] ^ 2;
mymac[1] = p[9];
mymac[2] = p[10];
mymac[3] = p[13];
mymac[4] = p[14];
mymac[5] = p[15];
}
}
int