From feb4900c25deabaf9b54760e40aea5e65499e987 Mon Sep 17 00:00:00 2001 From: Laurent Vivier Date: Wed, 6 Mar 2024 16:58:35 +1100 Subject: checksum: use csum_ip4_header() in udp.c and tcp.c We can find the same function to compute the IPv4 header checksum in tcp.c, udp.c and tap.c Use the function defined for tap.c, csum_ip4_header(), but with the code used in tcp.c and udp.c as it doesn't need a fully initialiazed IPv4 header, only protocol, tot_len, saddr and daddr. Signed-off-by: Laurent Vivier Reviewed-by: David Gibson Message-ID: <20240303135114.1023026-7-lvivier@redhat.com> [dwg: Fix weird cppcheck regression; it appears to be a problem in pre-existing code, but somehow this patch is exposing it] Signed-off-by: David Gibson Signed-off-by: Stefano Brivio --- checksum.c | 24 +++++++++++++++++++----- 1 file changed, 19 insertions(+), 5 deletions(-) (limited to 'checksum.c') diff --git a/checksum.c b/checksum.c index 643957b..1ac7975 100644 --- a/checksum.c +++ b/checksum.c @@ -57,6 +57,7 @@ #include #include "util.h" +#include "ip.h" #include "checksum.h" /* Checksums are optional for UDP over IPv4, so we usually just set @@ -114,13 +115,26 @@ uint16_t csum_fold(uint32_t sum) } /** - * csum_ip4_header() - Calculate and set IPv4 header checksum - * @ip4h: IPv4 header + * csum_ip4_header() - Calculate IPv4 header checksum + * @tot_len: IPv4 payload length (data + IP header, network order) + * @protocol: Protocol number (network order) + * @saddr: IPv4 source address (network order) + * @daddr: IPv4 destination address (network order) + * + * Return: 16-bit folded sum of the IPv4 header */ -void csum_ip4_header(struct iphdr *ip4h) +uint16_t csum_ip4_header(uint16_t tot_len, uint8_t protocol, + struct in_addr saddr, struct in_addr daddr) { - ip4h->check = 0; - ip4h->check = csum(ip4h, (size_t)ip4h->ihl * 4, 0); + uint32_t sum = L2_BUF_IP4_PSUM(protocol); + + sum += tot_len; + sum += (saddr.s_addr >> 16) & 0xffff; + sum += saddr.s_addr & 0xffff; + sum += (daddr.s_addr >> 16) & 0xffff; + sum += daddr.s_addr & 0xffff; + + return ~csum_fold(sum); } /** -- cgit v1.2.3