From 67151090bc349d9eec5a0b303d0cb3347b755251 Mon Sep 17 00:00:00 2001 From: David Gibson Date: Wed, 27 Nov 2024 14:54:05 +1100 Subject: [PATCH] iov, checksum: Replace csum_iov() with csum_iov_tail() We usually want to checksum only the tail part of a frame, excluding at least some headers. csum_iov() does that for a frame represented as an IO vector, not actually summing the entire IO vector. We now have struct iov_tail to explicitly represent this construct, so replace csum_iov() with csum_iov_tail() taking that representation rather than 3 parameters. We propagate the same change to csum_udp4() and csum_udp6() which take similar parameters. This slightly simplifies the code, and will allow some further simplifications as struct iov_tail is more widely used. Signed-off-by: David Gibson Signed-off-by: Stefano Brivio --- checksum.c | 56 +++++++++++++++++++++--------------------------------- checksum.h | 8 ++++---- iov.c | 1 - tap.c | 6 ++++-- tcp.c | 6 ++++-- udp.c | 7 ++++--- udp_vu.c | 9 +++++---- 7 files changed, 43 insertions(+), 50 deletions(-) diff --git a/checksum.c b/checksum.c index c673993..1c4354d 100644 --- a/checksum.c +++ b/checksum.c @@ -166,24 +166,22 @@ uint32_t proto_ipv4_header_psum(uint16_t l4len, uint8_t protocol, * @udp4hr: UDP header, initialised apart from checksum * @saddr: IPv4 source address * @daddr: IPv4 destination address - * @iov: Pointer to the array of IO vectors - * @iov_cnt: Length of the array - * @offset: UDP payload offset in the iovec array + * @data: UDP payload (as IO vector tail) */ void csum_udp4(struct udphdr *udp4hr, struct in_addr saddr, struct in_addr daddr, - const struct iovec *iov, int iov_cnt, size_t offset) + struct iov_tail *data) { /* UDP checksums are optional, so don't bother */ udp4hr->check = 0; if (UDP4_REAL_CHECKSUMS) { - uint16_t l4len = iov_size(iov, iov_cnt) - offset + - sizeof(struct udphdr); + uint16_t l4len = iov_tail_size(data) + sizeof(struct udphdr); uint32_t psum = proto_ipv4_header_psum(l4len, IPPROTO_UDP, saddr, daddr); + psum = csum_unfolded(udp4hr, sizeof(struct udphdr), psum); - udp4hr->check = csum_iov(iov, iov_cnt, offset, psum); + udp4hr->check = csum_iov_tail(data, psum); } } @@ -231,22 +229,20 @@ uint32_t proto_ipv6_header_psum(uint16_t payload_len, uint8_t protocol, * @udp6hr: UDP header, initialised apart from checksum * @saddr: Source address * @daddr: Destination address - * @iov: Pointer to the array of IO vectors - * @iov_cnt: Length of the array - * @offset: UDP payload offset in the iovec array + * @data: UDP payload (as IO vector tail) */ void csum_udp6(struct udphdr *udp6hr, const struct in6_addr *saddr, const struct in6_addr *daddr, - const struct iovec *iov, int iov_cnt, size_t offset) + struct iov_tail *data) { - uint16_t l4len = iov_size(iov, iov_cnt) - offset + - sizeof(struct udphdr); + uint16_t l4len = iov_tail_size(data) + sizeof(struct udphdr); uint32_t psum = proto_ipv6_header_psum(l4len, IPPROTO_UDP, saddr, daddr); + udp6hr->check = 0; psum = csum_unfolded(udp6hr, sizeof(struct udphdr), psum); - udp6hr->check = csum_iov(iov, iov_cnt, offset, psum); + udp6hr->check = csum_iov_tail(data, psum); } /** @@ -501,31 +497,23 @@ uint16_t csum(const void *buf, size_t len, uint32_t init) } /** - * csum_iov() - Calculates the unfolded checksum over an array of IO vectors - * - * @iov Pointer to the array of IO vectors - * @n Length of the array - * @offset: Offset of the data to checksum within the full data length + * csum_iov_tail() - Calculate unfolded checksum for the tail of an IO vector + * @tail: IO vector tail to checksum * @init Initial 32-bit checksum, 0 for no pre-computed checksum * * Return: 16-bit folded, complemented checksum */ -uint16_t csum_iov(const struct iovec *iov, size_t n, size_t offset, - uint32_t init) +uint16_t csum_iov_tail(struct iov_tail *tail, uint32_t init) { - unsigned int i; - size_t first; - - i = iov_skip_bytes(iov, n, offset, &first); - if (i >= n) - return (uint16_t)~csum_fold(init); - - init = csum_unfolded((char *)iov[i].iov_base + first, - iov[i].iov_len - first, init); - i++; - - for (; i < n; i++) - init = csum_unfolded(iov[i].iov_base, iov[i].iov_len, init); + if (iov_tail_prune(tail)) { + size_t i; + init = csum_unfolded((char *)tail->iov[0].iov_base + tail->off, + tail->iov[0].iov_len - tail->off, init); + for (i = 1; i < tail->cnt; i++) { + const struct iovec *iov = &tail->iov[i]; + init = csum_unfolded(iov->iov_base, iov->iov_len, init); + } + } return (uint16_t)~csum_fold(init); } diff --git a/checksum.h b/checksum.h index 31ba322..e243c97 100644 --- a/checksum.h +++ b/checksum.h @@ -9,6 +9,7 @@ struct udphdr; struct icmphdr; struct icmp6hdr; +struct iov_tail; uint32_t sum_16b(const void *buf, size_t len); uint16_t csum_fold(uint32_t sum); @@ -19,20 +20,19 @@ uint32_t proto_ipv4_header_psum(uint16_t l4len, uint8_t protocol, struct in_addr saddr, struct in_addr daddr); void csum_udp4(struct udphdr *udp4hr, struct in_addr saddr, struct in_addr daddr, - const struct iovec *iov, int iov_cnt, size_t offset); + struct iov_tail *data); void csum_icmp4(struct icmphdr *icmp4hr, const void *payload, size_t dlen); uint32_t proto_ipv6_header_psum(uint16_t payload_len, uint8_t protocol, const struct in6_addr *saddr, const struct in6_addr *daddr); void csum_udp6(struct udphdr *udp6hr, const struct in6_addr *saddr, const struct in6_addr *daddr, - const struct iovec *iov, int iov_cnt, size_t offset); + struct iov_tail *data); void csum_icmp6(struct icmp6hdr *icmp6hr, const struct in6_addr *saddr, const struct in6_addr *daddr, const void *payload, size_t dlen); uint32_t csum_unfolded(const void *buf, size_t len, uint32_t init); uint16_t csum(const void *buf, size_t len, uint32_t init); -uint16_t csum_iov(const struct iovec *iov, size_t n, size_t offset, - uint32_t init); +uint16_t csum_iov_tail(struct iov_tail *tail, uint32_t init); #endif /* CHECKSUM_H */ diff --git a/iov.c b/iov.c index 4c6416c..2f7be15 100644 --- a/iov.c +++ b/iov.c @@ -185,7 +185,6 @@ bool iov_tail_prune(struct iov_tail *tail) * * Returns: The total size in bytes. */ -/* cppcheck-suppress unusedFunction */ size_t iov_tail_size(struct iov_tail *tail) { iov_tail_prune(tail); diff --git a/tap.c b/tap.c index cde1719..c418064 100644 --- a/tap.c +++ b/tap.c @@ -184,11 +184,12 @@ void tap_udp4_send(const struct ctx *c, struct in_addr src, in_port_t sport, .iov_base = (void *)in, .iov_len = dlen }; + struct iov_tail payload = IOV_TAIL(&iov, 1, 0); uh->source = htons(sport); uh->dest = htons(dport); uh->len = htons(l4len); - csum_udp4(uh, src, dst, &iov, 1, 0); + csum_udp4(uh, src, dst, &payload); memcpy(data, in, dlen); tap_send_single(c, buf, dlen + (data - buf)); @@ -271,11 +272,12 @@ void tap_udp6_send(const struct ctx *c, .iov_base = in, .iov_len = dlen }; + struct iov_tail payload = IOV_TAIL(&iov, 1, 0); uh->source = htons(sport); uh->dest = htons(dport); uh->len = htons(l4len); - csum_udp6(uh, src, dst, &iov, 1, 0); + csum_udp6(uh, src, dst, &payload); memcpy(data, in, dlen); tap_send_single(c, buf, dlen + (data - buf)); diff --git a/tcp.c b/tcp.c index 61c12a5..f334ca5 100644 --- a/tcp.c +++ b/tcp.c @@ -764,6 +764,7 @@ void tcp_update_check_tcp4(const struct iphdr *iph, size_t l4offset) { uint16_t l4len = ntohs(iph->tot_len) - sizeof(struct iphdr); + struct iov_tail l4 = IOV_TAIL(iov, iov_cnt, l4offset); struct in_addr saddr = { .s_addr = iph->saddr }; struct in_addr daddr = { .s_addr = iph->daddr }; size_t check_ofs; @@ -801,7 +802,7 @@ void tcp_update_check_tcp4(const struct iphdr *iph, check = (uint16_t *)ptr; *check = 0; - *check = csum_iov(iov, iov_cnt, l4offset, sum); + *check = csum_iov_tail(&l4, sum); } /** @@ -815,6 +816,7 @@ void tcp_update_check_tcp6(const struct ipv6hdr *ip6h, const struct iovec *iov, int iov_cnt, size_t l4offset) { + struct iov_tail l4 = IOV_TAIL(iov, iov_cnt, l4offset); uint16_t l4len = ntohs(ip6h->payload_len); size_t check_ofs; uint16_t *check; @@ -852,7 +854,7 @@ void tcp_update_check_tcp6(const struct ipv6hdr *ip6h, check = (uint16_t *)ptr; *check = 0; - *check = csum_iov(iov, iov_cnt, l4offset, sum); + *check = csum_iov_tail(&l4, sum); } /** diff --git a/udp.c b/udp.c index 5b0093a..c89f031 100644 --- a/udp.c +++ b/udp.c @@ -316,7 +316,8 @@ size_t udp_update_hdr4(struct iphdr *ip4h, struct udp_payload_t *bp, .iov_base = bp->data, .iov_len = dlen }; - csum_udp4(&bp->uh, *src, *dst, &iov, 1, 0); + struct iov_tail data = IOV_TAIL(&iov, 1, 0); + csum_udp4(&bp->uh, *src, *dst, &data); } return l4len; @@ -360,8 +361,8 @@ size_t udp_update_hdr6(struct ipv6hdr *ip6h, struct udp_payload_t *bp, .iov_base = bp->data, .iov_len = dlen }; - csum_udp6(&bp->uh, &toside->oaddr.a6, &toside->eaddr.a6, - &iov, 1, 0); + struct iov_tail data = IOV_TAIL(&iov, 1, 0); + csum_udp6(&bp->uh, &toside->oaddr.a6, &toside->eaddr.a6, &data); } return l4len; diff --git a/udp_vu.c b/udp_vu.c index c911022..9c697f3 100644 --- a/udp_vu.c +++ b/udp_vu.c @@ -199,15 +199,16 @@ static void udp_vu_csum(const struct flowside *toside, int iov_used) const struct in_addr *dst4 = inany_v4(&toside->eaddr); char *base = iov_vu[0].iov_base; struct udp_payload_t *bp; + struct iov_tail data; if (src4 && dst4) { bp = vu_payloadv4(base); - csum_udp4(&bp->uh, *src4, *dst4, iov_vu, iov_used, - (char *)&bp->data - base); + data = IOV_TAIL(iov_vu, iov_used, (char *)&bp->data - base); + csum_udp4(&bp->uh, *src4, *dst4, &data); } else { bp = vu_payloadv6(base); - csum_udp6(&bp->uh, &toside->oaddr.a6, &toside->eaddr.a6, - iov_vu, iov_used, (char *)&bp->data - base); + data = IOV_TAIL(iov_vu, iov_used, (char *)&bp->data - base); + csum_udp6(&bp->uh, &toside->oaddr.a6, &toside->eaddr.a6, &data); } }