/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _NF_REJECT_H
#define _NF_REJECT_H

#include <linux/types.h>
#include <uapi/linux/in.h>

static inline bool nf_reject_verify_csum(struct sk_buff *skb, int dataoff,
                                          __u8 proto)
{
        /* Skip protocols that don't use 16-bit one's complement checksum
         * of the entire payload.
         */
        switch (proto) {
                /* Protocols with optional checksums. */
                case IPPROTO_UDP: {
                        const struct udphdr *udp_hdr;
                        struct udphdr _udp_hdr;

                        udp_hdr = skb_header_pointer(skb, dataoff,
                                                     sizeof(_udp_hdr),
                                                     &_udp_hdr);
                        if (!udp_hdr || udp_hdr->check)
                                return true;

                        return false;
                }
                case IPPROTO_GRE:

                /* Protocols with other integrity checks. */
                case IPPROTO_AH:
                case IPPROTO_ESP:
                case IPPROTO_SCTP:

                /* Protocols with partial checksums. */
                case IPPROTO_UDPLITE:
                        return false;
        }
        return true;
}

#endif /* _NF_REJECT_H */