svn commit: r308748 - head/sys/netgraph
Gleb Smirnoff
glebius at FreeBSD.org
Fri Nov 18 00:01:03 UTC 2016
On Thu, Nov 17, 2016 at 03:56:57PM -0800, Gleb Smirnoff wrote:
T> On Thu, Nov 17, 2016 at 10:44:12PM +0800, Sepherosa Ziehau wrote:
T> S> On Thu, Nov 17, 2016 at 10:03 PM, Bjoern A. Zeeb <bz at freebsd.org> wrote:
T> S> > Author: bz
T> S> > Date: Thu Nov 17 14:03:44 2016
T> S> > New Revision: 308748
T> S> > URL: https://svnweb.freebsd.org/changeset/base/308748
T> S> >
T> S> > Log:
T> S> > Writing out the L2TP control packet requires 12 bytes of
T> S> > contiguous memory but in one path we did not always guarantee this,
T> S> > thus do a m_pullup() there.
T> S> >
T> S> > PR: 214385
T> S> > Submitted by: Joe Jones (joeknockando googlemail.com)
T> S> > MFC after: 3 days
T> S> >
T> S> > Modified:
T> S> > head/sys/netgraph/ng_l2tp.c
T> S> >
T> S> > Modified: head/sys/netgraph/ng_l2tp.c
T> S> > ==============================================================================
T> S> > --- head/sys/netgraph/ng_l2tp.c Thu Nov 17 11:48:07 2016 (r308747)
T> S> > +++ head/sys/netgraph/ng_l2tp.c Thu Nov 17 14:03:44 2016 (r308748)
T> S> > @@ -1544,6 +1544,16 @@ ng_l2tp_xmit_ctrl(priv_p priv, struct mb
T> S> > priv->stats.memoryFailures++;
T> S> > return (ENOBUFS);
T> S> > }
T> S> > +
T> S> > + /*
T> S> > + * The below requires 12 contiguous bytes for the L2TP header
T> S> > + * to be written into.
T> S> > + */
T> S> > + m = m_pullup(m, 12);
T> S> > + if (m == NULL) {
T> S> > + priv->stats.memoryFailures++;
T> S> > + return (ENOBUFS);
T> S> > + }
T> S>
T> S> Would it be better that we do a (m->m_len < 12) test before doing the
T> S> m_pullup()?
T>
T> Yes, and a line like:
T>
T> if (m->m_len < 12 && (m = m_pullup(m, 12)) == NULL)
T>
T> will also match the style of the rest of the code in the function.
I think the whole block can be shortened to:
- prepend 10
- pullup 12
- read session_id at offset 10
The first pullup can be removed.
--
Totus tuus, Glebius.
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