[dpdk-users] IP Reassembly with more 4 packets crash

[Abhijeet Baruah]

I had been making a mistake. My code was of format -

if (rte_ipv4_frag_pkt_is_fragmented(ipv4_header))
{
  rte_mbuf* assembled_msg = rte_ipv4_frag_reassemble_packet();
  if (assembled_msg != nullptr)
  {
    rte_ip_frag_free_death_row();
  }
}

The rte_ip_frag_free_death_row was NOT getting called when reassembly was
failing, as it was in my case of > 4 IP fragments. The fix is to call
rte_ip_frag_free_death_row irrespective of reassembly status.

On Tue, Aug 13, 2019 at 8:59 AM Stephen Hemminger <
stephen at networkplumber.org> wrote:

> On Tue, 13 Aug 2019 08:37:09 +0530
> Abhijeet Baruah <abhijeet080808 at gmail.com> wrote:
>
> > Hi,
> >
> > I have looked at previous mails on this mailing list and also elsewhere
> on
> > Google and could not find any information related to this.
> >
> > Whenever I have to reassemble a valid IP packet with more than 4
> fragments,
> > I see a crash. Stack trace below. I assume the number 4 comes
> > from RTE_LIBRTE_IP_FRAG_MAX_FRAG.
> >
> > (gdb) bt
> > #0  ip_frag_lookup (tbl=tbl at entry=0x7fff7a32ce80, key=key at entry
> =0x7ffff6eeee10,
> > tms=tms at entry=2602613353715115, free=free at entry=0x7ffff6eeedb8,
> >     stale=stale at entry=0x7ffff6eeedc0) at
> >
> /usr/src/debug/dpdk-17.11.2-6.fc30.x86_64/lib/librte_ip_frag/ip_frag_internal.c:379
> > #1  0x00007ffff7c021f6 in ip_frag_find (tbl=tbl at entry=0x7fff7a32ce80,
> > dr=dr at entry=0x7fff7a32c900, key=key at entry=0x7ffff6eeee10,
> > tms=2602613353715115)
> >     at
> >
> /usr/src/debug/dpdk-17.11.2-6.fc30.x86_64/lib/librte_ip_frag/ip_frag_internal.c:286
> > #2  0x00007ffff7c00280 in rte_ipv4_frag_reassemble_packet
> > (tbl=0x7fff7a32ce80, dr=0x7fff7a32c900, mb=0x7fff8b71b480, tms=<optimized
> > out>,
> >     ip_hdr=<optimized out>) at
> >
> /usr/src/debug/dpdk-17.11.2-6.fc30.x86_64/lib/librte_ip_frag/rte_ipv4_reassembly.c:160
> >
> > (gdb) f 0
> > #0  ip_frag_lookup (tbl=tbl at entry=0x7fff7a32ce80, key=key at entry
> =0x7ffff6eeee10,
> > tms=tms at entry=2602613353715115, free=free at entry=0x7ffff6eeedb8,
> >     stale=stale at entry=0x7ffff6eeedc0) at
> >
> /usr/src/debug/dpdk-17.11.2-6.fc30.x86_64/lib/librte_ip_frag/ip_frag_internal.c:379
> > 379 if (ip_frag_key_cmp(key, &p1[i].key) == 0)
> >
> > (gdb) f 1
> > #1  0x00007ffff7c021f6 in ip_frag_find (tbl=tbl at entry=0x7fff7a32ce80,
> > dr=dr at entry=0x7fff7a32c900, key=key at entry=0x7ffff6eeee10,
> > tms=2602613353715115)
> >     at
> >
> /usr/src/debug/dpdk-17.11.2-6.fc30.x86_64/lib/librte_ip_frag/ip_frag_internal.c:286
> > 286 if ((pkt = ip_frag_lookup(tbl, key, tms, &free, &stale)) == NULL) {
> >
> > (gdb) f 2
> > #2  0x00007ffff7c00280 in rte_ipv4_frag_reassemble_packet
> > (tbl=0x7fff7a32ce80, dr=0x7fff7a32c900, mb=0x7fff8b71b480, tms=<optimized
> > out>,
> >     ip_hdr=<optimized out>) at
> >
> /usr/src/debug/dpdk-17.11.2-6.fc30.x86_64/lib/librte_ip_frag/rte_ipv4_reassembly.c:160
> > 160 if ((fp = ip_frag_find(tbl, dr, &key, tms)) == NULL) {
> >
> > Is this a known issue? Are there any workaround?
> >
> > Regards,
> > Abhijeet
>
> Please try and reproduce with latest DPDK 19.08.
>