Add csum_icmp4() helper for calculating ICMP checksums

Although tap_ip_send() is currently the only place calculating ICMP
checksums, create a helper function for symmetry with ICMPv6.  For
future flexibility it allows the ICMPv6 header and payload to be in
separate buffers.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/checksum.h b/checksum.h
index d7daabf..bf0620f 100644
--- a/checksum.h
+++ b/checksum.h
@@ -6,11 +6,13 @@
 #ifndef CHECKSUM_H
 #define CHECKSUM_H
 
+struct icmphdr;
 struct icmp6hdr;
 
 uint32_t sum_16b(const void *buf, size_t len);
 uint16_t csum_fold(uint32_t sum);
 uint16_t csum_unaligned(const void *buf, size_t len, uint32_t init);
+void csum_icmp4(struct icmphdr *ih, const void *payload, size_t len);
 void csum_icmp6(struct icmp6hdr *icmp6hr,
 		const struct in6_addr *saddr, const struct in6_addr *daddr,
 		const void *payload, size_t len);