On 1/4/2022 9:10 PM, Li, Xiaoyun wrote:
Hi
-----Original Message-----
From: Li, Xiaoyun<xiaoyun...@intel.com>
Sent: Tuesday, January 4, 2022 15:19
To: Singh, Aman Deep<aman.deep.si...@intel.com>; Yigit, Ferruh
<ferruh.yi...@intel.com>;olivier.m...@6wind.com;
m...@smartsharesystems.com; Ananyev, Konstantin
<konstantin.anan...@intel.com>;step...@networkplumber.org;
Medvedkin, Vladimir<vladimir.medved...@intel.com>
Cc:dev@dpdk.org
Subject: RE: [PATCH v4 1/2] net: add functions to calculate UDP/TCP cksum in
mbuf
Hi
-----Original Message-----
From: Singh, Aman Deep<aman.deep.si...@intel.com>
Sent: Wednesday, December 15, 2021 11:34
To: Li, Xiaoyun<xiaoyun...@intel.com>; Yigit, Ferruh
<ferruh.yi...@intel.com>;olivier.m...@6wind.com;
m...@smartsharesystems.com; Ananyev, Konstantin
<konstantin.anan...@intel.com>;step...@networkplumber.org;
Medvedkin,
Vladimir<vladimir.medved...@intel.com>
Cc:dev@dpdk.org
Subject: Re: [PATCH v4 1/2] net: add functions to calculate UDP/TCP
cksum in mbuf
On 12/3/2021 5:08 PM, Xiaoyun Li wrote:
Add functions to call rte_raw_cksum_mbuf() to calculate IPv4/6
UDP/TCP checksum in mbuf which can be over multi-segments.
Signed-off-by: Xiaoyun Li<xiaoyun...@intel.com>
Acked-by: Aman Singh <aman.deep.si...@intel.com>
---
doc/guides/rel_notes/release_22_03.rst | 10 ++
lib/net/rte_ip.h | 186 +++++++++++++++++++++++++
lib/net/version.map | 10 ++
3 files changed, 206 insertions(+)
diff --git a/doc/guides/rel_notes/release_22_03.rst
b/doc/guides/rel_notes/release_22_03.rst
index 6d99d1eaa9..7a082c4427 100644
--- a/doc/guides/rel_notes/release_22_03.rst
+++ b/doc/guides/rel_notes/release_22_03.rst
@@ -55,6 +55,13 @@ New Features
Also, make sure to start the actual text at the margin.
=======================================================
+* **Added functions to calculate UDP/TCP checksum in mbuf.**
+ * Added the following functions to calculate UDP/TCP checksum of
packets
+ which can be over multi-segments:
+ - ``rte_ipv4_udptcp_cksum_mbuf()``
+ - ``rte_ipv4_udptcp_cksum_mbuf_verify()``
+ - ``rte_ipv6_udptcp_cksum_mbuf()``
+ - ``rte_ipv6_udptcp_cksum_mbuf_verify()``
Removed Items
-------------
@@ -84,6 +91,9 @@ API Changes
Also, make sure to start the actual text at the margin.
=======================================================
+* net: added experimental functions
+``rte_ipv4_udptcp_cksum_mbuf()``,
+ ``rte_ipv4_udptcp_cksum_mbuf_verify()``,
+``rte_ipv6_udptcp_cksum_mbuf()``,
+ ``rte_ipv6_udptcp_cksum_mbuf_verify()``
ABI Changes
-----------
diff --git a/lib/net/rte_ip.h b/lib/net/rte_ip.h index
c575250852..534f401d26 100644
--- a/lib/net/rte_ip.h
+++ b/lib/net/rte_ip.h
@@ -400,6 +400,65 @@ rte_ipv4_udptcp_cksum(const struct
rte_ipv4_hdr
*ipv4_hdr, const void *l4_hdr)
return cksum;
}
+/**
+ * @internal Calculate the non-complemented IPv4 L4 checksum of a
+packet */ static inline uint16_t
+__rte_ipv4_udptcp_cksum_mbuf(const
+struct rte_mbuf *m,
+ const struct rte_ipv4_hdr *ipv4_hdr,
+ uint16_t l4_off)
+{
+ uint16_t raw_cksum;
+ uint32_t cksum;
+
+ if (l4_off > m->pkt_len)
+ return 0;
+
+ if (rte_raw_cksum_mbuf(m, l4_off, m->pkt_len - l4_off,
&raw_cksum))
+ return 0;
+
+ cksum = raw_cksum + rte_ipv4_phdr_cksum(ipv4_hdr, 0);
+
+ cksum = ((cksum & 0xffff0000) >> 16) + (cksum & 0xffff);
At times, even after above operation "cksum" might stay above 16-bits,
ex "cksum = 0x1FFFF" to start with.
Can we consider using "return __rte_raw_cksum_reduce(cksum);"
Will use it in next version. Thanks.
Also, not related to this patch. It means that __rte_ipv4_udptcp_cksum and
__rte_ipv6_udptcp_cksum have the same issue, right?
Should anyone fix that?
Forgot the intent here.
rte_raw_cksum_mbuf() already calls __rte_raw_cksum_reduce().
So actually, it's a result of uint16_t + uint16_t. So it's impossible of your
case. There's no need to call __rte_raw_cksum_reduce().
Got it, Thanks. With u16 + u16, max 1-bit overflow only possible. So
effective operation here reduces to-
cksum = ((cksum & 0x10000) >> 16) + (cksum & 0xffff);
+
+ return (uint16_t)cksum;
+}
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice.
+ *
+ * Compute the IPv4 UDP/TCP checksum of a packet.
+ *
+ * @param m
+ * The pointer to the mbuf.
+ * @param ipv4_hdr
+ * The pointer to the contiguous IPv4 header.
+ * @param l4_off
+ * The offset in bytes to start L4 checksum.
+ * @return
+ * The complemented checksum to set in the L4 header.
+ */
+__rte_experimental
+static inline uint16_t
+rte_ipv4_udptcp_cksum_mbuf(const struct rte_mbuf *m,
+ const struct rte_ipv4_hdr *ipv4_hdr, uint16_t l4_off)
{
+ uint16_t cksum = __rte_ipv4_udptcp_cksum_mbuf(m, ipv4_hdr,
l4_off);
+
+ cksum = ~cksum;
+
+ /*
+ * Per RFC 768: If the computed checksum is zero for UDP,
+ * it is transmitted as all ones
+ * (the equivalent in one's complement arithmetic).
+ */
+ if (cksum == 0 && ipv4_hdr->next_proto_id == IPPROTO_UDP)
+ cksum = 0xffff;
+
+ return cksum;
+}
+
/**
* Validate the IPv4 UDP or TCP checksum.
*
@@ -426,6 +485,38 @@ rte_ipv4_udptcp_cksum_verify(const struct
rte_ipv4_hdr *ipv4_hdr,
return 0;
}
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice.
+ *
+ * Verify the IPv4 UDP/TCP checksum of a packet.
+ *
+ * In case of UDP, the caller must first check if
+udp_hdr->dgram_cksum is 0
+ * (i.e. no checksum).
+ *
+ * @param m
+ * The pointer to the mbuf.
+ * @param ipv4_hdr
+ * The pointer to the contiguous IPv4 header.
+ * @param l4_off
+ * The offset in bytes to start L4 checksum.
+ * @return
+ * Return 0 if the checksum is correct, else -1.
+ */
+__rte_experimental
+static inline uint16_t
+rte_ipv4_udptcp_cksum_mbuf_verify(const struct rte_mbuf *m,
+ const struct rte_ipv4_hdr *ipv4_hdr,
+ uint16_t l4_off)
+{
+ uint16_t cksum = __rte_ipv4_udptcp_cksum_mbuf(m, ipv4_hdr,
l4_off);
+
+ if (cksum != 0xffff)
+ return -1;
cksum other than 0xffff, should return error. Is that the intent or I
am missing something obvious.
This is the intent. This function is to verify if the cksum in the packet is
correct.
It's different from calling rte_ipv4/6_udptcp_cksum_mbuf(). When calling
rte_ipv4/6_udptcp_cksum_mbuf(), you need to set the cksum in udp/tcp
header as 0. Then calculate the cksum.
But here, user should directly call this function with the original packet. Then
if the udp/tcp cksum is correct, after the calculation (please note that, this
is
calling __rte_ipv4_udptcp_cksum_mbuf(), so the result needs to be ~), it
should be 0xffff, namely, ~cksum = 0 which means cksum is correct. You can
see rte_ipv4/6_udptcp_cksum_verify() is doing the same.
+
+ return 0;
+}
+
/**
* IPv6 Header
*/
@@ -538,6 +629,68 @@ rte_ipv6_udptcp_cksum(const struct
rte_ipv6_hdr
*ipv6_hdr, const void *l4_hdr)
return cksum;
}
+/**
+ * @internal Calculate the non-complemented IPv6 L4 checksum of a
+packet */ static inline uint16_t
+__rte_ipv6_udptcp_cksum_mbuf(const
+struct rte_mbuf *m,
+ const struct rte_ipv6_hdr *ipv6_hdr,
+ uint16_t l4_off)
+{
+ uint16_t raw_cksum;
+ uint32_t cksum;
+
+ if (l4_off > m->pkt_len)
+ return 0;
+
+ if (rte_raw_cksum_mbuf(m, l4_off, m->pkt_len - l4_off,
&raw_cksum))
+ return 0;
+
+ cksum = raw_cksum + rte_ipv6_phdr_cksum(ipv6_hdr, 0);
+
+ cksum = ((cksum & 0xffff0000) >> 16) + (cksum & 0xffff);
Same, please check if we can opt for __rte_raw_cksum_reduce(cksum)
+
+ return (uint16_t)cksum;
+}
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice.
+ *
+ * Process the IPv6 UDP or TCP checksum of a packet.
+ *
+ * The IPv6 header must not be followed by extension headers. The
+layer 4
+ * checksum must be set to 0 in the L4 header by the caller.
+ *
+ * @param m
+ * The pointer to the mbuf.
+ * @param ipv6_hdr
+ * The pointer to the contiguous IPv6 header.
+ * @param l4_off
+ * The offset in bytes to start L4 checksum.
+ * @return
+ * The complemented checksum to set in the L4 header.
+ */
+__rte_experimental
+static inline uint16_t
+rte_ipv6_udptcp_cksum_mbuf(const struct rte_mbuf *m,
+ const struct rte_ipv6_hdr *ipv6_hdr, uint16_t l4_off)
{
+ uint16_t cksum = __rte_ipv6_udptcp_cksum_mbuf(m, ipv6_hdr,
l4_off);
+
+ cksum = ~cksum;
+
+ /*
+ * Per RFC 768: If the computed checksum is zero for UDP,
+ * it is transmitted as all ones
+ * (the equivalent in one's complement arithmetic).
+ */
+ if (cksum == 0 && ipv6_hdr->proto == IPPROTO_UDP)
+ cksum = 0xffff;
+
+ return cksum;
+}
+
/**
* Validate the IPv6 UDP or TCP checksum.
*
@@ -565,6 +718,39 @@ rte_ipv6_udptcp_cksum_verify(const struct
rte_ipv6_hdr *ipv6_hdr,
return 0;
}
+/**
+ * @warning
+ * @b EXPERIMENTAL: this API may change without prior notice.
+ *
+ * Validate the IPv6 UDP or TCP checksum of a packet.
+ *
+ * In case of UDP, the caller must first check if udp_hdr->dgram_cksum is
0:
+ * this is either invalid or means no checksum in some situations.
+See 8.1
+ * (Upper-Layer Checksums) in RFC 8200.
+ *
+ * @param m
+ * The pointer to the mbuf.
+ * @param ipv6_hdr
+ * The pointer to the contiguous IPv6 header.
+ * @param l4_off
+ * The offset in bytes to start L4 checksum.
+ * @return
+ * Return 0 if the checksum is correct, else -1.
+ */
+__rte_experimental
+static inline int
+rte_ipv6_udptcp_cksum_mbuf_verify(const struct rte_mbuf *m,
+ const struct rte_ipv6_hdr *ipv6_hdr,
+ uint16_t l4_off)
+{
+ uint16_t cksum = __rte_ipv6_udptcp_cksum_mbuf(m, ipv6_hdr,
l4_off);
+
+ if (cksum != 0xffff)
+ return -1;
+
+ return 0;
+}
+
/** IPv6 fragment extension header. */
#define RTE_IPV6_EHDR_MF_SHIFT 0
#define RTE_IPV6_EHDR_MF_MASK 1
diff --git a/lib/net/version.map b/lib/net/version.map index
4f4330d1c4..0f2aacdef8 100644
--- a/lib/net/version.map
+++ b/lib/net/version.map
@@ -12,3 +12,13 @@ DPDK_22 {
local: *;
};
+
+EXPERIMENTAL {
+ global:
+
+ # added in 22.03
+ rte_ipv4_udptcp_cksum_mbuf;
+ rte_ipv4_udptcp_cksum_mbuf_verify;
+ rte_ipv6_udptcp_cksum_mbuf;
+ rte_ipv6_udptcp_cksum_mbuf_verify;
+};
