CVSROOT: /cvs
Module name: src
Changes by: d...@cvs.openbsd.org 2016/10/09 20:44:17
Modified files:
sys/net : if_ethersubr.c if_vlan.c
Log message:
ensure prepended ethernet headers are placed on ETHER_ALIGN boundaries,
even if m_prepend allocates a new mbuf in front of the current one.
this is done by asking M_PREPEND for ETHER_HDR_LEN + ETHER_ALIGN bytes,
and then calling m_adj(ETHER_ALIGN) after.
in the case M_PREPEND does not allocate a new mbuf and ends up with the
same layout as before.
in the allocation case, the requested length is provided on a long
boundary. an ETHER_HDR_LEN request would therefore be 6 bytes
allocated on a long boundary, when we want it to be at ETHER_ALIGN.
by asking for ETHER_HDR_LEN plus ETHER_ALIGN, we can m_adj ETHER_ALIGN
off to get us to the ETHER_ALIGN offset.
ok yasuoka@ mikeb@
