lpm6: fix buffer overflow
lpm6: fix buffer overflow

This patch fixes buffer overflow reported by ASAN,
please reference https://bugs.dpdk.org/show_bug.cgi?id=819

The rte_lpm6 keeps routing information for control plane purpose
inside the rte_hash table which uses rte_jhash() as a hash function.
From the rte_jhash() documentation: If input key is not aligned to
four byte boundaries or a multiple of four bytes in length,
the memory region just after may be read (but not used in the
computation).
rte_lpm6 uses 17 bytes keys consisting of IPv6 address (16 bytes) +
depth (1 byte).

This patch increases the size of the depth field up to uint32_t
and sets the alignment to 4 bytes.

Bugzilla ID: 819
Fixes: 86b3b21952a8 ("lpm6: store rules in hash table")
Cc: stable@dpdk.org

Signed-off-by: Vladimir Medvedkin <085731b4c6f11a88aba42f72e5e495cf937bde5a@intel.com>
Acked-by: Bruce Richardson <66b9e8e8fbd5e9f41f91b0af050876182ce9d0e4@intel.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk