This patch is RFC and would be applied after "flow_dissector:
Protocol specific flow dissector offload"
In order to maitain uAPI in flower, the FLOW_DISSECTOR_F_FLOWER flag
is added to indicate to flow_dissector that the caller is flower.
As new funtionality is addes to flow_dissector that would break
the flower uAPI, the code can be wrapped in "if (!(flags &
FLOW_DISSECTOR_F_FLOWER)).
In this patch the conditional is use around protocol specific
dissection (e.g. DPI into VXLAN) as well as the code that
enforces a depth of parsing to prevent DPI. The latter was a
recent patch that would introduce a parsing limit to flower that
did not exist before (i.e. would break uAPI).
Signed-off-by: Tom Herbert <t...@quantonium.net>
---
include/net/flow_dissector.h | 1 +
net/core/flow_dissector.c | 17 +++++++++++------
net/sched/cls_flow.c | 3 ++-
3 files changed, 14 insertions(+), 7 deletions(-)
diff --git a/include/net/flow_dissector.h b/include/net/flow_dissector.h
index ad75bbfd1c9c..ca315107d147 100644
--- a/include/net/flow_dissector.h
+++ b/include/net/flow_dissector.h
@@ -214,6 +214,7 @@ enum flow_dissector_key_id {
#define FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL BIT(2)
#define FLOW_DISSECTOR_F_STOP_AT_ENCAP BIT(3)
#define FLOW_DISSECTOR_F_STOP_AT_L4 BIT(4)
+#define FLOW_DISSECTOR_F_FLOWER BIT(5)
struct flow_dissector_key {
enum flow_dissector_key_id key_id;
diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index 84b8eb1f6664..a4d5843ec34e 100644
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -383,8 +383,11 @@ __skb_flow_dissect_ipv6(const struct sk_buff *skb,
*/
#define MAX_FLOW_DISSECT_HDRS 15
-static bool skb_flow_dissect_allowed(int *num_hdrs)
+static bool skb_flow_dissect_allowed(int *num_hdrs, unsigned int flags)
{
+ if (flags & FLOW_DISSECTOR_F_FLOWER)
+ return true;
+
++*num_hdrs;
return (*num_hdrs <= MAX_FLOW_DISSECT_HDRS);
@@ -722,7 +725,8 @@ bool __skb_flow_dissect(struct sk_buff *skb,
break;
default:
- fdret = flow_dissect_by_type(skb, proto, key_control,
+ if (!(flags & FLOW_DISSECTOR_F_FLOWER))
+ fdret = flow_dissect_by_type(skb, proto, key_control,
flow_dissector,
target_container,
data, &proto, &ip_proto, &nhoff,
@@ -735,7 +739,7 @@ bool __skb_flow_dissect(struct sk_buff *skb,
case FLOW_DISSECT_RET_OUT_GOOD:
goto out_good;
case FLOW_DISSECT_RET_PROTO_AGAIN:
- if (skb_flow_dissect_allowed(&num_hdrs))
+ if (skb_flow_dissect_allowed(&num_hdrs, flags))
goto proto_again;
goto out_good;
case FLOW_DISSECT_RET_CONTINUE:
@@ -843,7 +847,8 @@ bool __skb_flow_dissect(struct sk_buff *skb,
break;
default:
- fdret = flow_dissect_by_type_proto(skb, proto,
+ if (!(flags & FLOW_DISSECTOR_F_FLOWER))
+ fdret = flow_dissect_by_type_proto(skb, proto,
ip_proto, key_control,
flow_dissector,
target_container,
@@ -872,11 +877,11 @@ bool __skb_flow_dissect(struct sk_buff *skb,
/* Process result of IP proto processing */
switch (fdret) {
case FLOW_DISSECT_RET_PROTO_AGAIN:
- if (skb_flow_dissect_allowed(&num_hdrs))
+ if (skb_flow_dissect_allowed(&num_hdrs, flags))
goto proto_again;
break;
case FLOW_DISSECT_RET_IPPROTO_AGAIN:
- if (skb_flow_dissect_allowed(&num_hdrs))
+ if (skb_flow_dissect_allowed(&num_hdrs, flags))
goto ip_proto_again;
break;
case FLOW_DISSECT_RET_OUT_GOOD:
diff --git a/net/sched/cls_flow.c b/net/sched/cls_flow.c
index 2a3a60ec5b86..ad4ac503697e 100644
--- a/net/sched/cls_flow.c
+++ b/net/sched/cls_flow.c
@@ -315,7 +315,8 @@ static int flow_classify(struct sk_buff *skb, const struct
tcf_proto *tp,
keymask = f->keymask;
if (keymask & FLOW_KEYS_NEEDED)
- skb_flow_dissect_flow_keys(skb, &flow_keys, 0);
+ skb_flow_dissect_flow_keys(skb, &flow_keys,
+ FLOW_DISSECTOR_F_FLOWER);
for (n = 0; n < f->nkeys; n++) {
key = ffs(keymask) - 1;
--
2.11.0
