On Wed, 27 May 2020 15:31:41 +0100
Andrew Rybchenko <arybche...@solarflare.com> wrote:
> SW VLAN insertion relies on Ethernet addresses location in contigous
> memory (do not split across mbuf segments). There is no any formal
> requirements on data location and mbuf structure which guarantee it.
> So, check it explicitly to avoid corrupted packets if the condition
> is violated. Typically software VLAN insertion is done on Tx prepare
> stage and application will get indication that the packet is invalid
> and cannot be transmitted.
>
> Signed-off-by: Andrew Rybchenko <arybche...@solarflare.com>
> ---
> lib/librte_net/rte_ether.h | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/lib/librte_net/rte_ether.h b/lib/librte_net/rte_ether.h
> index 0ae4e75b6c..d7c076bba8 100644
> --- a/lib/librte_net/rte_ether.h
> +++ b/lib/librte_net/rte_ether.h
> @@ -357,6 +357,10 @@ static inline int rte_vlan_insert(struct rte_mbuf **m)
> if (!RTE_MBUF_DIRECT(*m) || rte_mbuf_refcnt_read(*m) > 1)
> return -EINVAL;
>
> + /* Can't insert header if the first segment is too short */
> + if (rte_pktmbuf_data_len(*m) < 2 * RTE_ETHER_ADDR_LEN)
> + return -EINVAL;
Looks good, but you could also make it handle the fragment case with:
diff --git a/lib/librte_net/rte_ether.h b/lib/librte_net/rte_ether.h
index 0ae4e75b6c58..4d0e310a4fac 100644
--- a/lib/librte_net/rte_ether.h
+++ b/lib/librte_net/rte_ether.h
@@ -350,14 +350,18 @@ static inline int rte_vlan_strip(struct rte_mbuf *m)
*/
static inline int rte_vlan_insert(struct rte_mbuf **m)
{
- struct rte_ether_hdr *oh, *nh;
+ struct rte_ether_hdr *nh, tmp;
+ const struct rte_ether_hdr *oh;
struct rte_vlan_hdr *vh;
/* Can't insert header if mbuf is shared */
if (!RTE_MBUF_DIRECT(*m) || rte_mbuf_refcnt_read(*m) > 1)
return -EINVAL;
- oh = rte_pktmbuf_mtod(*m, struct rte_ether_hdr *);
+ oh = rte_pktmbuf_read(*m, 0, sizeof(*oh), &tmp);
+ if (unlikely(oh == NULL))
+ return -EINVAL;
+
nh = (struct rte_ether_hdr *)
rte_pktmbuf_prepend(*m, sizeof(struct rte_vlan_hdr));
if (nh == NULL)
