Hi-----Original Message----- From: Li, Xiaoyun <xiaoyun.li@intel.com> Sent: Tuesday, January 4, 2022 15:19 To: Singh, Aman Deep <aman.deep.singh@intel.com>; Yigit, Ferruh <ferruh.yigit@intel.com>; olivier.matz@6wind.com; mb@smartsharesystems.com; Ananyev, Konstantin <konstantin.ananyev@intel.com>; stephen@networkplumber.org; Medvedkin, Vladimir <vladimir.medvedkin@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.singh@intel.com> Sent: Wednesday, December 15, 2021 11:34 To: Li, Xiaoyun <xiaoyun.li@intel.com>; Yigit, Ferruh <ferruh.yigit@intel.com>; olivier.matz@6wind.com; mb@smartsharesystems.com; Ananyev, Konstantin <konstantin.ananyev@intel.com>; stephen@networkplumber.org;Medvedkin,Vladimir <vladimir.medvedkin@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.li@intel.com>
Acked-by: Aman Singh <aman.deep.singh@intel.com>
Got it, Thanks. With u16 + u16, max 1-bit overflow only possible. So effective operation here reduces to---- 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 ofpackets+ 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 structrte_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().
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 structrte_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 structrte_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 structrte_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 is0:+ * 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; +};