include/net/netfilter/nf_tables_ipv4.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _NF_TABLES_IPV4_H_
   3 #define _NF_TABLES_IPV4_H_
   4
   5 #include <net/netfilter/nf_tables.h>
   6 #include <net/ip.h>
   7
   8 static inline void
   9 nft_set_pktinfo_ipv4(struct nft_pktinfo *pkt,
  10                      struct sk_buff *skb,
  11                      const struct nf_hook_state *state)
  12 {
  13         struct iphdr *ip;
  14
  15         nft_set_pktinfo(pkt, skb, state);
  16
  17         ip = ip_hdr(pkt->skb);
  18         pkt->tprot_set = true;
  19         pkt->tprot = ip->protocol;
  20         pkt->xt.thoff = ip_hdrlen(pkt->skb);
  21         pkt->xt.fragoff = ntohs(ip->frag_off) & IP_OFFSET;
  22 }
  23
  24 static inline int
  25 __nft_set_pktinfo_ipv4_validate(struct nft_pktinfo *pkt,
  26                                 struct sk_buff *skb,
  27                                 const struct nf_hook_state *state)
  28 {
  29         struct iphdr *iph, _iph;
  30         u32 len, thoff;
  31
  32         iph = skb_header_pointer(skb, skb_network_offset(skb), sizeof(*iph),
  33                                  &_iph);
  34         if (!iph)
  35                 return -1;
  36
  37         if (iph->ihl < 5 || iph->version != 4)
  38                 return -1;
  39
  40         len = ntohs(iph->tot_len);
  41         thoff = iph->ihl * 4;
  42         if (skb->len < len)
  43                 return -1;
  44         else if (len < thoff)
  45                 return -1;
  46
  47         pkt->tprot_set = true;
  48         pkt->tprot = iph->protocol;
  49         pkt->xt.thoff = thoff;
  50         pkt->xt.fragoff = ntohs(iph->frag_off) & IP_OFFSET;
  51
  52         return 0;
  53 }
  54
  55 static inline void
  56 nft_set_pktinfo_ipv4_validate(struct nft_pktinfo *pkt,
  57                               struct sk_buff *skb,
  58                               const struct nf_hook_state *state)
  59 {
  60         nft_set_pktinfo(pkt, skb, state);
  61         if (__nft_set_pktinfo_ipv4_validate(pkt, skb, state) < 0)
  62                 nft_set_pktinfo_proto_unspec(pkt, skb);
  63 }
  64
  65 extern struct nft_af_info nft_af_ipv4;
  66
  67 #endif