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Extend fixes made in r278103 and r38754 by copying the complete packet

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header and not only partial flags and fields. Firewalls can attach
classification tags to the outgoing mbufs which should be copied to
all the new fragments. Else only the first fragment will be let
through by the firewall. This can easily be tested by sending a large
ping packet through a firewall. It was also discovered that VLAN
related flags and fields should be copied for packets traversing
through VLANs. This is all handled by "m_dup_pkthdr()".

Regarding the MAC policy check in ip_fragment(), the tag provided by
the originating mbuf is copied instead of using the default one
provided by m_gethdr().

Tested by:		Karim Fodil-Lemelin <fodillemlinkarim at gmail.com>
MFC after:		2 weeks
Sponsored by:		Mellanox Technologies
PR:			7802
This commit is contained in:
Hans Petter Selasky 2015-04-02 15:47:37 +00:00
parent 033749179f
commit c4c4346f5f
1 changed files with 13 additions and 7 deletions
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20
sys/netinet/ip_output.c
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@ -774,11 +774,19 @@ ip_fragment(struct ip *ip, struct mbuf **m_frag, int mtu,
IPSTAT_INC(ips_odropped);
goto done;
}
/* make sure the flowid is the same for the fragmented mbufs */
M_HASHTYPE_SET(m, M_HASHTYPE_GET(m0));
m->m_pkthdr.flowid = m0->m_pkthdr.flowid;
/* copy multicast flag, if any */
m->m_flags |= (m0->m_flags & M_MCAST);
/*
* Make sure the complete packet header gets copied
* from the originating mbuf to the newly created
* mbuf. This also ensures that existing firewall
* classification(s), VLAN tags and so on get copied
* to the resulting fragmented packet(s):
*/
if (m_dup_pkthdr(m, m0, M_NOWAIT) == 0) {
m_free(m);
error = ENOBUFS;
IPSTAT_INC(ips_odropped);
goto done;
}
/*
* In the first mbuf, leave room for the link header, then
* copy the original IP header including options. The payload
@ -808,11 +816,9 @@ ip_fragment(struct ip *ip, struct mbuf **m_frag, int mtu,
goto done;
}
m->m_pkthdr.len = mhlen + len;
m->m_pkthdr.rcvif = NULL;
#ifdef MAC
mac_netinet_fragment(m0, m);
#endif
m->m_pkthdr.csum_flags = m0->m_pkthdr.csum_flags;
mhip->ip_off = htons(mhip->ip_off);
mhip->ip_sum = 0;
if (m->m_pkthdr.csum_flags & CSUM_IP & ~if_hwassist_flags) {