tcp, udp: Pad batched frames for vhost-user modes to 60 bytes (802.3 minimum)

For both TCP and UDP, instead of just expecting the first provided
buffer to be large enough to contain the headers we need (from 42
bytes for UDP data over IPv4 to 82 bytes for TCP with options over
IPv6), change that assumption to make sure that buffers are anyway
at least ETH_ZLEN-sized buffers (60 bytes).

This looks reasonable because there are no known vhost-user
hypervisor implementations that would give us smaller buffers than
that, and we would anyway hit an assertion failure with IPv6 if we
ever had less than 60 bytes per buffer.

At this point, all we need to do is to pad the first (and only)
buffer, should data and headers use less than that.

Link: https://bugs.passt.top/show_bug.cgi?id=166
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

0 files changed, 0 insertions, 0 deletions