From 6905ac75ec6643fbc93963ad9ded4903e8eeebf0 Mon Sep 17 00:00:00 2001 From: David Gibson Date: Wed, 19 Oct 2022 11:43:46 +1100 Subject: Add csum_udp6() helper for calculating UDP over IPv6 checksums Add a helper for calculating UDP checksums when used over IPv6 For future flexibility, the new helper takes parameters for the fields in the IPv6 pseudo-header, so an IPv6 header or pseudo-header doesn't need to be explicitly constructed. It also allows the UDP header and payload to be in separate buffers, although we don't use this yet. Signed-off-by: David Gibson Signed-off-by: Stefano Brivio --- checksum.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) (limited to 'checksum.c') diff --git a/checksum.c b/checksum.c index f35c948..175381d 100644 --- a/checksum.c +++ b/checksum.c @@ -52,6 +52,7 @@ #include #include +#include #include #include @@ -123,6 +124,27 @@ void csum_icmp4(struct icmphdr *icmp4hr, const void *payload, size_t len) icmp4hr->checksum = csum_unaligned(payload, len, psum); } +/** + * csum_udp6() - Calculate and set checksum for a UDP over IPv6 packet + * @udp6hr: UDP header, initialised apart from checksum + * @payload: UDP packet payload + * @len: Length of @payload (not including UDP header) + */ +void csum_udp6(struct udphdr *udp6hr, + const struct in6_addr *saddr, const struct in6_addr *daddr, + const void *payload, size_t len) +{ + /* Partial checksum for the pseudo-IPv6 header */ + uint32_t psum = sum_16b(saddr, sizeof(*saddr)) + + sum_16b(daddr, sizeof(*daddr)) + + htons(len + sizeof(*udp6hr)) + htons(IPPROTO_UDP); + + udp6hr->check = 0; + /* Add in partial checksum for the UDP header alone */ + psum += sum_16b(udp6hr, sizeof(*udp6hr)); + udp6hr->check = csum_unaligned(payload, len, psum); +} + /** * csum_icmp6() - Calculate and set checksum for an ICMPv6 packet * @icmp6hr: ICMPv6 header, initialised apart from checksum -- cgit v1.2.3