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[62.23.145.78]) by smtp.gmail.com with ESMTPSA id h9sm21072213wmb.35.2021.04.27.06.58.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 27 Apr 2021 06:58:24 -0700 (PDT) From: Olivier Matz To: dev@dpdk.org Cc: Keith Wiles , Hongzhi Guo , =?utf-8?q?Morten_Br=C3=B8rup?= , Thomas Monjalon Date: Tue, 27 Apr 2021 15:57:54 +0200 Message-Id: <20210427135755.927-4-olivier.matz@6wind.com> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20210427135755.927-1-olivier.matz@6wind.com> References: <20210427135755.927-1-olivier.matz@6wind.com> MIME-Version: 1.0 Subject: [dpdk-dev] [PATCH 3/4] net: introduce functions to verify L4 checksums X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" Since commit d5df2ae0428a ("net: fix unneeded replacement of TCP checksum 0"), the functions rte_ipv4_udptcp_cksum() and rte_ipv6_udptcp_cksum() can return either 0x0000 or 0xffff when used to verify a packet containing a valid checksum. Since these functions should be used to calculate the checksum to set in a packet, introduce 2 new helpers for checksum verification. They return 0 if the checksum is valid in the packet. Use this new helper in net/tap driver. Signed-off-by: Olivier Matz Acked-by: Morten Brørup Reviewed-by: Morten Brørup Acked-by: Morten Brørup Reviewed-by: Morten Brørup --- drivers/net/tap/rte_eth_tap.c | 7 +- lib/net/rte_ip.h | 124 +++++++++++++++++++++++++++------- 2 files changed, 104 insertions(+), 27 deletions(-) diff --git a/drivers/net/tap/rte_eth_tap.c b/drivers/net/tap/rte_eth_tap.c index 71282e8065..b14d5a1d55 100644 --- a/drivers/net/tap/rte_eth_tap.c +++ b/drivers/net/tap/rte_eth_tap.c @@ -365,11 +365,12 @@ tap_verify_csum(struct rte_mbuf *mbuf) return; } } - cksum = rte_ipv4_udptcp_cksum(l3_hdr, l4_hdr); + cksum_ok = !rte_ipv4_udptcp_cksum_verify(l3_hdr, + l4_hdr); } else { /* l3 == RTE_PTYPE_L3_IPV6, checked above */ - cksum = rte_ipv6_udptcp_cksum(l3_hdr, l4_hdr); + cksum_ok = !rte_ipv6_udptcp_cksum_verify(l3_hdr, + l4_hdr); } - cksum_ok = (cksum == 0) || (cksum == 0xffff); mbuf->ol_flags |= cksum_ok ? PKT_RX_L4_CKSUM_GOOD : PKT_RX_L4_CKSUM_BAD; } diff --git a/lib/net/rte_ip.h b/lib/net/rte_ip.h index 8c189009b0..ef84bcc5bf 100644 --- a/lib/net/rte_ip.h +++ b/lib/net/rte_ip.h @@ -344,20 +344,10 @@ rte_ipv4_phdr_cksum(const struct rte_ipv4_hdr *ipv4_hdr, uint64_t ol_flags) } /** - * Process the IPv4 UDP or TCP checksum. - * - * The IP and layer 4 checksum must be set to 0 in the packet by - * the caller. - * - * @param ipv4_hdr - * The pointer to the contiguous IPv4 header. - * @param l4_hdr - * The pointer to the beginning of the L4 header. - * @return - * The complemented checksum to set in the IP packet. + * @internal Calculate the non-complemented IPv4 L4 checksum */ static inline uint16_t -rte_ipv4_udptcp_cksum(const struct rte_ipv4_hdr *ipv4_hdr, const void *l4_hdr) +__rte_ipv4_udptcp_cksum(const struct rte_ipv4_hdr *ipv4_hdr, const void *l4_hdr) { uint32_t cksum; uint32_t l3_len, l4_len; @@ -374,16 +364,62 @@ rte_ipv4_udptcp_cksum(const struct rte_ipv4_hdr *ipv4_hdr, const void *l4_hdr) cksum += rte_ipv4_phdr_cksum(ipv4_hdr, 0); cksum = ((cksum & 0xffff0000) >> 16) + (cksum & 0xffff); - cksum = (~cksum) & 0xffff; + + return (uint16_t)cksum; +} + +/** + * Process the IPv4 UDP or TCP checksum. + * + * The IP and layer 4 checksum must be set to 0 in the packet by + * the caller. + * + * @param ipv4_hdr + * The pointer to the contiguous IPv4 header. + * @param l4_hdr + * The pointer to the beginning of the L4 header. + * @return + * The complemented checksum to set in the IP packet. + */ +static inline uint16_t +rte_ipv4_udptcp_cksum(const struct rte_ipv4_hdr *ipv4_hdr, const void *l4_hdr) +{ + uint16_t cksum = __rte_ipv4_udptcp_cksum(ipv4_hdr, l4_hdr); + + cksum = ~cksum; + /* - * Per RFC 768:If the computed checksum is zero for UDP, + * 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 (uint16_t)cksum; + return cksum; +} + +/** + * Validate the IPv4 UDP or TCP checksum. + * + * @param ipv4_hdr + * The pointer to the contiguous IPv4 header. + * @param l4_hdr + * The pointer to the beginning of the L4 header. + * @return + * Return 0 if the checksum is correct, else -1. + */ +__rte_experimental +static inline int +rte_ipv4_udptcp_cksum_verify(const struct rte_ipv4_hdr *ipv4_hdr, + const void *l4_hdr) +{ + uint16_t cksum = __rte_ipv4_udptcp_cksum(ipv4_hdr, l4_hdr); + + if (cksum != 0xffff) + return -1; + + return 0; } /** @@ -448,6 +484,25 @@ rte_ipv6_phdr_cksum(const struct rte_ipv6_hdr *ipv6_hdr, uint64_t ol_flags) return __rte_raw_cksum_reduce(sum); } +/** + * @internal Calculate the non-complemented IPv4 L4 checksum + */ +static inline uint16_t +__rte_ipv6_udptcp_cksum(const struct rte_ipv6_hdr *ipv6_hdr, const void *l4_hdr) +{ + uint32_t cksum; + uint32_t l4_len; + + l4_len = rte_be_to_cpu_16(ipv6_hdr->payload_len); + + cksum = rte_raw_cksum(l4_hdr, l4_len); + cksum += rte_ipv6_phdr_cksum(ipv6_hdr, 0); + + cksum = ((cksum & 0xffff0000) >> 16) + (cksum & 0xffff); + + return (uint16_t)cksum; +} + /** * Process the IPv6 UDP or TCP checksum. * @@ -464,16 +519,10 @@ rte_ipv6_phdr_cksum(const struct rte_ipv6_hdr *ipv6_hdr, uint64_t ol_flags) static inline uint16_t rte_ipv6_udptcp_cksum(const struct rte_ipv6_hdr *ipv6_hdr, const void *l4_hdr) { - uint32_t cksum; - uint32_t l4_len; - - l4_len = rte_be_to_cpu_16(ipv6_hdr->payload_len); + uint16_t cksum = __rte_ipv6_udptcp_cksum(ipv6_hdr, l4_hdr); - cksum = rte_raw_cksum(l4_hdr, l4_len); - cksum += rte_ipv6_phdr_cksum(ipv6_hdr, 0); + cksum = ~cksum; - cksum = ((cksum & 0xffff0000) >> 16) + (cksum & 0xffff); - cksum = (~cksum) & 0xffff; /* * Per RFC 768: If the computed checksum is zero for UDP, * it is transmitted as all ones @@ -482,7 +531,34 @@ rte_ipv6_udptcp_cksum(const struct rte_ipv6_hdr *ipv6_hdr, const void *l4_hdr) if (cksum == 0 && ipv6_hdr->proto == IPPROTO_UDP) cksum = 0xffff; - return (uint16_t)cksum; + return cksum; +} + +/** + * Validate the IPv6 UDP or TCP checksum. + * + * The function accepts a 0 checksum, since it can exceptionally happen. See 8.1 + * (Upper-Layer Checksums) in RFC 8200. + * + * @param ipv6_hdr + * The pointer to the contiguous IPv6 header. + * @param l4_hdr + * The pointer to the beginning of the L4 header. + * @return + * Return 0 if the checksum is correct, else -1. + */ +__rte_experimental +static inline int +rte_ipv6_udptcp_cksum_verify(const struct rte_ipv6_hdr *ipv6_hdr, + const void *l4_hdr) +{ + uint16_t cksum; + + cksum = __rte_ipv6_udptcp_cksum(ipv6_hdr, l4_hdr); + if (cksum != 0xffff) + return -1; + + return 0; } /** IPv6 fragment extension header. */