diff mbox

[dpdk-dev,05/12] mbuf: add new Rx checksum mbuf flags

Message ID 1469088510-7552-6-git-send-email-olivier.matz@6wind.com (mailing list archive)
State Superseded, archived
Delegated to: Thomas Monjalon
Headers

Commit Message

Olivier Matz July 21, 2016, 8:08 a.m. UTC 
  Following discussions in [1] and [2], introduce a new bit to
describe the Rx checksum status in mbuf.

Before this patch, only one flag was available:
  PKT_RX_L4_CKSUM_BAD: L4 cksum of RX pkt. is not OK.

And same for L3:
  PKT_RX_IP_CKSUM_BAD: IP cksum of RX pkt. is not OK.

This had 2 issues:
- it was not possible to differentiate "checksum good" from
  "checksum unknown".
- it was not possible for a virtual driver to say "the checksum
  in packet may be wrong, but data integrity is valid".

This patch tries to solve this issue by having 4 states (2 bits)
for the IP and L4 Rx checksums. New values are:

 - PKT_RX_L4_CKSUM_UNKNOWN: no information about the RX L4 checksum
   -> the application should verify the checksum by sw
 - PKT_RX_L4_CKSUM_BAD: the L4 checksum in the packet is wrong
   -> the application can drop the packet without additional check
 - PKT_RX_L4_CKSUM_GOOD: the L4 checksum in the packet is valid
   -> the application can accept the packet without verifying the
      checksum by sw
 - PKT_RX_L4_CKSUM_NONE: the L4 checksum is not correct in the packet
   data, but the integrity of the L4 data is verified.
   -> the application can process the packet but must not verify the
      checksum by sw. It has to take care to recalculate the cksum
      if the packet is transmitted (either by sw or using tx offload)

  And same for L3 (replace L4 by IP in description above).

This commit tries to be compatible with existing applications that
only check the existing flag (CKSUM_BAD).

[1] http://dpdk.org/ml/archives/dev/2016-May/039920.html
[2] http://dpdk.org/ml/archives/dev/2016-June/040007.html

Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
---
 doc/guides/rel_notes/release_16_11.rst |  6 ++++
 lib/librte_mbuf/rte_mbuf.c             | 16 +++++++++--
 lib/librte_mbuf/rte_mbuf.h             | 51 ++++++++++++++++++++++++++++++++--
 3 files changed, 68 insertions(+), 5 deletions(-)

Comments

Stephen Hemminger July 21, 2016, 9:22 p.m. UTC | #1 
On Thu, 21 Jul 2016 10:08:23 +0200
Olivier Matz <olivier.matz@6wind.com> wrote:

> +/**
> + * Deprecated.
> + * Checking this flag alone is deprecated: check the 2 bits of
> + * PKT_RX_L4_CKSUM_MASK.
> + * This flag was set when the L4 checksum of a packet was detected as
> + * wrong by the hardware.
> + */
> +#define PKT_RX_L4_CKSUM_BAD  (1ULL << 3)
> +
> +/**
> + * Deprecated.
> + * Checking this flag alone is deprecated: check the 2 bits of
> + * PKT_RX_IP_CKSUM_MASK.
> + * This flag was set when the IP checksum of a packet was detected as
> + * wrong by the hardware.
> + */
> +#define PKT_RX_IP_CKSUM_BAD  (1ULL << 4)

I think you should use the GCC deprecated attribute, not sure how though
Olivier Matz July 22, 2016, 8:03 a.m. UTC | #2 
Hi Stephen,

On 07/21/2016 11:22 PM, Stephen Hemminger wrote:
> On Thu, 21 Jul 2016 10:08:23 +0200
> Olivier Matz <olivier.matz@6wind.com> wrote:
> 
>> +/**
>> + * Deprecated.
>> + * Checking this flag alone is deprecated: check the 2 bits of
>> + * PKT_RX_L4_CKSUM_MASK.
>> + * This flag was set when the L4 checksum of a packet was detected as
>> + * wrong by the hardware.
>> + */
>> +#define PKT_RX_L4_CKSUM_BAD  (1ULL << 3)
>> +
>> +/**
>> + * Deprecated.
>> + * Checking this flag alone is deprecated: check the 2 bits of
>> + * PKT_RX_IP_CKSUM_MASK.
>> + * This flag was set when the IP checksum of a packet was detected as
>> + * wrong by the hardware.
>> + */
>> +#define PKT_RX_IP_CKSUM_BAD  (1ULL << 4)
> 
> I think you should use the GCC deprecated attribute, not sure how though
> 

The reason why I did not use a macro poisoning here is because this flag
is still valid when used with the mask. Actually, checking this flag
alone still works and does the same as before but I wanted to highlight
that it should now be used with the mask.

Your comment makes me think that maybe the new flags could have
different names to avoid to keep old-style tests on this flag. On the
other hand, I think the name is already the good one, and doing this
would break the API and affect large pieces of code in dpdk.

Opinions are welcome here :)

Thanks for commenting
Olivier
diff mbox

Patch

diff --git a/doc/guides/rel_notes/release_16_11.rst b/doc/guides/rel_notes/release_16_11.rst
index da70f3b..8f4f24b 100644
--- a/doc/guides/rel_notes/release_16_11.rst
+++ b/doc/guides/rel_notes/release_16_11.rst
@@ -58,6 +58,12 @@  New Features
   Added a new function ``rte_pktmbuf_cksum()`` to process the checksum of
   data embedded in an mbuf chain.
 
+* **Added new Rx checksum mbuf flags.**
+
+  Added new Rx checksum flags in mbufs to described more states: unknown,
+  good, bad, or not present (useful for virtual drivers). This modification
+  was done for IP and L4.
+
 Resolved Issues
 ---------------
 
diff --git a/lib/librte_mbuf/rte_mbuf.c b/lib/librte_mbuf/rte_mbuf.c
index 0304245..c40b926 100644
--- a/lib/librte_mbuf/rte_mbuf.c
+++ b/lib/librte_mbuf/rte_mbuf.c
@@ -309,7 +309,11 @@  const char *rte_get_rx_ol_flag_name(uint64_t mask)
 	case PKT_RX_RSS_HASH: return "PKT_RX_RSS_HASH";
 	case PKT_RX_FDIR: return "PKT_RX_FDIR";
 	case PKT_RX_L4_CKSUM_BAD: return "PKT_RX_L4_CKSUM_BAD";
+	case PKT_RX_L4_CKSUM_GOOD: return "PKT_RX_L4_CKSUM_GOOD";
+	case PKT_RX_L4_CKSUM_NONE: return "PKT_RX_L4_CKSUM_NONE";
 	case PKT_RX_IP_CKSUM_BAD: return "PKT_RX_IP_CKSUM_BAD";
+	case PKT_RX_IP_CKSUM_GOOD: return "PKT_RX_IP_CKSUM_GOOD";
+	case PKT_RX_IP_CKSUM_NONE: return "PKT_RX_IP_CKSUM_NONE";
 	case PKT_RX_EIP_CKSUM_BAD: return "PKT_RX_EIP_CKSUM_BAD";
 	case PKT_RX_VLAN_STRIPPED: return "PKT_RX_VLAN_STRIPPED";
 	case PKT_RX_IEEE1588_PTP: return "PKT_RX_IEEE1588_PTP";
@@ -332,8 +336,16 @@  int rte_get_rx_ol_flag_list(uint64_t mask, char *buf, size_t buflen)
 		{ PKT_RX_VLAN_PKT, PKT_RX_VLAN_PKT, NULL },
 		{ PKT_RX_RSS_HASH, PKT_RX_RSS_HASH, NULL },
 		{ PKT_RX_FDIR, PKT_RX_FDIR, NULL },
-		{ PKT_RX_L4_CKSUM_BAD, PKT_RX_L4_CKSUM_BAD, NULL },
-		{ PKT_RX_IP_CKSUM_BAD, PKT_RX_IP_CKSUM_BAD, NULL },
+		{ PKT_RX_L4_CKSUM_BAD, PKT_RX_L4_CKSUM_MASK, NULL },
+		{ PKT_RX_L4_CKSUM_GOOD, PKT_RX_L4_CKSUM_MASK, NULL },
+		{ PKT_RX_L4_CKSUM_NONE, PKT_RX_L4_CKSUM_MASK, NULL },
+		{ PKT_RX_L4_CKSUM_UNKNOWN, PKT_RX_L4_CKSUM_MASK,
+		  "PKT_RX_L4_CKSUM_UNKNOWN" },
+		{ PKT_RX_IP_CKSUM_BAD, PKT_RX_IP_CKSUM_MASK, NULL },
+		{ PKT_RX_IP_CKSUM_GOOD, PKT_RX_IP_CKSUM_MASK, NULL },
+		{ PKT_RX_IP_CKSUM_NONE, PKT_RX_IP_CKSUM_MASK, NULL },
+		{ PKT_RX_IP_CKSUM_UNKNOWN, PKT_RX_IP_CKSUM_MASK,
+		  "PKT_RX_IP_CKSUM_UNKNOWN" },
 		{ PKT_RX_EIP_CKSUM_BAD, PKT_RX_EIP_CKSUM_BAD, NULL },
 		{ PKT_RX_VLAN_STRIPPED, PKT_RX_VLAN_STRIPPED, NULL },
 		{ PKT_RX_IEEE1588_PTP, PKT_RX_IEEE1588_PTP, NULL },
diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
index 7bbe096..841326d 100644
--- a/lib/librte_mbuf/rte_mbuf.h
+++ b/lib/librte_mbuf/rte_mbuf.h
@@ -91,8 +91,25 @@  extern "C" {
 
 #define PKT_RX_RSS_HASH      (1ULL << 1)  /**< RX packet with RSS hash result. */
 #define PKT_RX_FDIR          (1ULL << 2)  /**< RX packet with FDIR match indicate. */
-#define PKT_RX_L4_CKSUM_BAD  (1ULL << 3)  /**< L4 cksum of RX pkt. is not OK. */
-#define PKT_RX_IP_CKSUM_BAD  (1ULL << 4)  /**< IP cksum of RX pkt. is not OK. */
+
+/**
+ * Deprecated.
+ * Checking this flag alone is deprecated: check the 2 bits of
+ * PKT_RX_L4_CKSUM_MASK.
+ * This flag was set when the L4 checksum of a packet was detected as
+ * wrong by the hardware.
+ */
+#define PKT_RX_L4_CKSUM_BAD  (1ULL << 3)
+
+/**
+ * Deprecated.
+ * Checking this flag alone is deprecated: check the 2 bits of
+ * PKT_RX_IP_CKSUM_MASK.
+ * This flag was set when the IP checksum of a packet was detected as
+ * wrong by the hardware.
+ */
+#define PKT_RX_IP_CKSUM_BAD  (1ULL << 4)
+
 #define PKT_RX_EIP_CKSUM_BAD (1ULL << 5)  /**< External IP header checksum error. */
 
 /**
@@ -102,7 +119,35 @@  extern "C" {
  */
 #define PKT_RX_VLAN_STRIPPED (1ULL << 6)
 
-/* hole, some bits can be reused here  */
+/**
+ * Mask of bits used to determine the status of RX IP checksum.
+ * - PKT_RX_IP_CKSUM_UNKNOWN: no information about the RX IP checksum
+ * - PKT_RX_IP_CKSUM_BAD: the IP checksum in the packet is wrong
+ * - PKT_RX_IP_CKSUM_GOOD: the IP checksum in the packet is valid
+ * - PKT_RX_IP_CKSUM_NONE: the IP checksum is not correct in the packet
+ *   data, but the integrity of the IP header is verified.
+ */
+#define PKT_RX_IP_CKSUM_MASK ((1ULL << 4) | (1ULL << 7))
+
+#define PKT_RX_IP_CKSUM_UNKNOWN 0
+#define PKT_RX_IP_CKSUM_BAD     (1ULL << 4)
+#define PKT_RX_IP_CKSUM_GOOD    (1ULL << 7)
+#define PKT_RX_IP_CKSUM_NONE    ((1ULL << 4) | (1ULL << 7))
+
+/**
+ * Mask of bits used to determine the status of RX L4 checksum.
+ * - PKT_RX_L4_CKSUM_UNKNOWN: no information about the RX L4 checksum
+ * - PKT_RX_L4_CKSUM_BAD: the L4 checksum in the packet is wrong
+ * - PKT_RX_L4_CKSUM_GOOD: the L4 checksum in the packet is valid
+ * - PKT_RX_L4_CKSUM_NONE: the L4 checksum is not correct in the packet
+ *   data, but the integrity of the L4 data is verified.
+ */
+#define PKT_RX_L4_CKSUM_MASK ((1ULL << 3) | (1ULL << 8))
+
+#define PKT_RX_L4_CKSUM_UNKNOWN 0
+#define PKT_RX_L4_CKSUM_BAD     (1ULL << 3)
+#define PKT_RX_L4_CKSUM_GOOD    (1ULL << 8)
+#define PKT_RX_L4_CKSUM_NONE    ((1ULL << 3) | (1ULL << 8))
 
 #define PKT_RX_IEEE1588_PTP  (1ULL << 9)  /**< RX IEEE1588 L2 Ethernet PT Packet. */
 #define PKT_RX_IEEE1588_TMST (1ULL << 10) /**< RX IEEE1588 L2/L4 timestamped packet.*/