net: mctp: copy skb ext data when fragmenting

If we're fragmenting on local output, the original packet may contain
ext data for the MCTP flows. We'll want this in the resulting fragment
skbs too.

So, do a skb_ext_copy() in the fragmentation path, and implement the
MCTP-specific parts of an ext copy operation.

Fixes: 67737c457281 ("mctp: Pass flow data & flow release events to drivers")
Reported-by: Jian Zhang <zhangjian.3032@bytedance.com>
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index b9de3ee65ae6439725237f07e0d05c02e7c90cb4..1f918e602bc4f61fc09aa7308f9c47e8cacae47b 100644 (file)
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -6849,6 +6849,14 @@ static struct skb_ext *skb_ext_maybe_cow(struct skb_ext *old,
                for (i = 0; i < sp->len; i++)
                        xfrm_state_hold(sp->xvec[i]);
        }
+#endif
+#ifdef CONFIG_MCTP_FLOWS
+       if (old_active & (1 << SKB_EXT_MCTP)) {
+               struct mctp_flow *flow = skb_ext_get_ptr(old, SKB_EXT_MCTP);
+
+               if (flow->key)
+                       refcount_inc(&flow->key->refs);
+       }
 #endif
        __skb_ext_put(old);
        return new;

diff --git a/net/mctp/route.c b/net/mctp/route.c
index 28648a7ec866664bfe35a28c51d34026bb6201cf..34e5131135093d65f7c6dd495542a56b5a62206f 100644 (file)
--- a/net/mctp/route.c
+++ b/net/mctp/route.c
@@ -905,6 +905,9 @@ static int mctp_do_fragment_route(struct mctp_route *rt, struct sk_buff *skb,
                /* copy message payload */
                skb_copy_bits(skb, pos, skb_transport_header(skb2), size);
 
+               /* we need to copy the extensions, for MCTP flow data */
+               skb_ext_copy(skb2, skb);
+
                /* do route */
                rc = rt->output(rt, skb2);
                if (rc)