Date: Fri, 20 Mar 2015 11:18:58 -0400 From: Karim Fodil-Lemelin <fodillemlinkarim@gmail.com> To: freebsd-net <freebsd-net@freebsd.org> Subject: Another fragment question / patch Message-ID: <550C3A62.3080403@gmail.com>
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Hi, While reading through a previous comment on this list about fragments I've noticed that mbuf tags aren't being copied from the leading fragment (header) to the subsequent fragment packets. In other words, one would expect that all fragments of a packet are carrying the same tags that were set on the original packet. I have built a simple test were I use ipfw with ALTQ and sent large packet (bigger then MTU) off that BSD machine. I have observed that the leading fragment (m0) packet is going through the right class although the next fragments are hitting the default class for unclassified packets. Here is a patch that makes things works as expected (all fragments carry the ALTQ tag): diff --git a/freebsd/sys/netinet/ip_output.c b/freebsd/sys/netinet/ip_output.c index d650949..7d8f041 100644 --- a/freebsd/sys/netinet/ip_output.c +++ b/freebsd/sys/netinet/ip_output.c @@ -1184,7 +1184,10 @@ smart_frag_failure: ipstat.ips_odropped++; goto done; } - m->m_flags |= (m0->m_flags & M_MCAST) | M_FRAG; + + m->m_flags |= (m0->m_flags & M_COPYFLAGS) | M_FRAG; + m_tag_copy_chain(m, m0, M_NOWAIT); + /* * In the first mbuf, leave room for the link header, then * copy the original IP header including options. The payload diff --git a/freebsd/sys/sys/mbuf.h b/freebsd/sys/sys/mbuf.h index 2efff38..6ad8439 100644 --- a/freebsd/sys/sys/mbuf.h I hope this helps, Karim.
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