netfilter/nf_reject.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _NF_REJECT_H
   3 #define _NF_REJECT_H
   4
   5 #include <linux/types.h>
   6 #include <uapi/linux/in.h>
   7
   8 static inline bool nf_reject_verify_csum(struct sk_buff *skb, int dataoff,
   9                                           __u8 proto)
  10 {
  11         /* Skip protocols that don't use 16-bit one's complement checksum
  12          * of the entire payload.
  13          */
  14         switch (proto) {
  15                 /* Protocols with optional checksums. */
  16                 case IPPROTO_UDP: {
  17                         const struct udphdr *udp_hdr;
  18                         struct udphdr _udp_hdr;
  19
  20                         udp_hdr = skb_header_pointer(skb, dataoff,
  21                                                      sizeof(_udp_hdr),
  22                                                      &_udp_hdr);
  23                         if (!udp_hdr || udp_hdr->check)
  24                                 return true;
  25
  26                         return false;
  27                 }
  28                 case IPPROTO_GRE:
  29
  30                 /* Protocols with other integrity checks. */
  31                 case IPPROTO_AH:
  32                 case IPPROTO_ESP:
  33                 case IPPROTO_SCTP:
  34
  35                 /* Protocols with partial checksums. */
  36                 case IPPROTO_UDPLITE:
  37                 case IPPROTO_DCCP:
  38                         return false;
  39         }
  40         return true;
  41 }
  42
  43 #endif /* _NF_REJECT_H */