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ip_frag: use key length for key comparison

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Right now reassembly code relies on src_dst[] being all zeroes to
determine is it  free/occupied entry in the fragments table.
This is suboptimal and error prone - user can crash DPDK ip_reassembly
app by something like the following scapy script:
x=Ether(src=...,dst=...)/IP(dst='0.0.0.0',src='0.0.0.0',id=0)/('X'*1000)
frags=fragment(x, fragsize=500)
sendp(frags, iface=...)
To overcome that issue and reduce overhead of
'key invalidate'  and 'key is empty' operations -
add key_len into keys comparision procedure.

Fixes: 4f1a8f633862 ("ip_frag: add IPv6 reassembly")
Cc: stable@dpdk.org

Reported-by: Ryan E Hall <ryan.e.hall@intel.com>
Reported-by: Alexander V Gutkin <alexander.v.gutkin@intel.com>
Signed-off-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
This commit is contained in:
Konstantin Ananyev 2018-11-05 12:18:58 +00:00 committed by Thomas Monjalon
parent 7f0983ee33
commit b8d5dfd4a5
2 changed files with 15 additions and 13 deletions
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14
lib/librte_ip_frag/ip_frag_common.h
View File

@ -58,20 +58,14 @@ struct rte_mbuf *ipv6_frag_reassemble(struct ip_frag_pkt *fp);
static inline int
ip_frag_key_is_empty(const struct ip_frag_key * key)
{
uint32_t i;
for (i = 0; i < RTE_MIN(key->key_len, RTE_DIM(key->src_dst)); i++)
if (key->src_dst[i] != 0)
return 0;
return 1;
return (key->key_len == 0);
}
/* empty the key */
/* invalidate the key */
static inline void
ip_frag_key_invalidate(struct ip_frag_key * key)
{
uint32_t i;
for (i = 0; i < key->key_len; i++)
key->src_dst[i] = 0;
key->key_len = 0;
}
/* compare two keys */
@ -80,7 +74,7 @@ ip_frag_key_cmp(const struct ip_frag_key * k1, const struct ip_frag_key * k2)
{
uint32_t i;
uint64_t val;
val = k1->id ^ k2->id;
val = k1->id_key_len ^ k2->id_key_len;
for (i = 0; i < k1->key_len; i++)
val |= k1->src_dst[i] ^ k2->src_dst[i];
return val;

14
lib/librte_ip_frag/rte_ip_frag.h
View File

@ -44,9 +44,17 @@ struct ip_frag {
/** @internal <src addr, dst_addr, id> to uniquely identify fragmented datagram. */
struct ip_frag_key {
uint64_t src_dst[4]; /**< src address, first 8 bytes used for IPv4 */
uint32_t id; /**< dst address */
uint32_t key_len; /**< src/dst key length */
uint64_t src_dst[4];
/**< src and dst address, only first 8 bytes used for IPv4 */
RTE_STD_C11
union {
uint64_t id_key_len; /**< combined for easy fetch */
__extension__
struct {
uint32_t id; /**< packet id */
uint32_t key_len; /**< src/dst key length */
};
};
};
/**