include/net/inet_ecn.h

   1 #ifndef _INET_ECN_H_
   2 #define _INET_ECN_H_
   3
   4 #include <linux/ip.h>
   5 #include <linux/skbuff.h>
   6
   7 #include <net/inet_sock.h>
   8 #include <net/dsfield.h>
   9
  10 enum {
  11         INET_ECN_NOT_ECT = 0,
  12         INET_ECN_ECT_1 = 1,
  13         INET_ECN_ECT_0 = 2,
  14         INET_ECN_CE = 3,
  15         INET_ECN_MASK = 3,
  16 };
  17
  18 static inline int INET_ECN_is_ce(__u8 dsfield)
  19 {
  20         return (dsfield & INET_ECN_MASK) == INET_ECN_CE;
  21 }
  22
  23 static inline int INET_ECN_is_not_ect(__u8 dsfield)
  24 {
  25         return (dsfield & INET_ECN_MASK) == INET_ECN_NOT_ECT;
  26 }
  27
  28 static inline int INET_ECN_is_capable(__u8 dsfield)
  29 {
  30         return (dsfield & INET_ECN_ECT_0);
  31 }
  32
  33 static inline __u8 INET_ECN_encapsulate(__u8 outer, __u8 inner)
  34 {
  35         outer &= ~INET_ECN_MASK;
  36         outer |= !INET_ECN_is_ce(inner) ? (inner & INET_ECN_MASK) :
  37                                           INET_ECN_ECT_0;
  38         return outer;
  39 }
  40
  41 #define INET_ECN_xmit(sk) do { inet_sk(sk)->tos |= INET_ECN_ECT_0; } while (0)
  42 #define INET_ECN_dontxmit(sk) \
  43         do { inet_sk(sk)->tos &= ~INET_ECN_MASK; } while (0)
  44
  45 #define IP6_ECN_flow_init(label) do {           \
  46       (label) &= ~htonl(INET_ECN_MASK << 20);   \
  47     } while (0)
  48
  49 #define IP6_ECN_flow_xmit(sk, label) do {                               \
  50         if (INET_ECN_is_capable(inet_sk(sk)->tos))                      \
  51                 (label) |= htonl(INET_ECN_ECT_0 << 20);                 \
  52     } while (0)
  53
  54 static inline int IP_ECN_set_ce(struct iphdr *iph)
  55 {
  56         u32 check = (__force u32)iph->check;
  57         u32 ecn = (iph->tos + 1) & INET_ECN_MASK;
  58
  59         /*
  60          * After the last operation we have (in binary):
  61          * INET_ECN_NOT_ECT => 01
  62          * INET_ECN_ECT_1   => 10
  63          * INET_ECN_ECT_0   => 11
  64          * INET_ECN_CE      => 00
  65          */
  66         if (!(ecn & 2))
  67                 return !ecn;
  68
  69         /*
  70          * The following gives us:
  71          * INET_ECN_ECT_1 => check += htons(0xFFFD)
  72          * INET_ECN_ECT_0 => check += htons(0xFFFE)
  73          */
  74         check += (__force u16)htons(0xFFFB) + (__force u16)htons(ecn);
  75
  76         iph->check = (__force __sum16)(check + (check>=0xFFFF));
  77         iph->tos |= INET_ECN_CE;
  78         return 1;
  79 }
  80
  81 static inline void IP_ECN_clear(struct iphdr *iph)
  82 {
  83         iph->tos &= ~INET_ECN_MASK;
  84 }
  85
  86 static inline void ipv4_copy_dscp(struct iphdr *outer, struct iphdr *inner)
  87 {
  88         u32 dscp = ipv4_get_dsfield(outer) & ~INET_ECN_MASK;
  89         ipv4_change_dsfield(inner, INET_ECN_MASK, dscp);
  90 }
  91
  92 struct ipv6hdr;
  93
  94 static inline int IP6_ECN_set_ce(struct ipv6hdr *iph)
  95 {
  96         if (INET_ECN_is_not_ect(ipv6_get_dsfield(iph)))
  97                 return 0;
  98         *(__be32*)iph |= htonl(INET_ECN_CE << 20);
  99         return 1;
 100 }
 101
 102 static inline void IP6_ECN_clear(struct ipv6hdr *iph)
 103 {
 104         *(__be32*)iph &= ~htonl(INET_ECN_MASK << 20);
 105 }
 106
 107 static inline void ipv6_copy_dscp(struct ipv6hdr *outer, struct ipv6hdr *inner)
 108 {
 109         u32 dscp = ipv6_get_dsfield(outer) & ~INET_ECN_MASK;
 110         ipv6_change_dsfield(inner, INET_ECN_MASK, dscp);
 111 }
 112
 113 static inline int INET_ECN_set_ce(struct sk_buff *skb)
 114 {
 115         switch (skb->protocol) {
 116         case __constant_htons(ETH_P_IP):
 117                 if (skb_network_header(skb) + sizeof(struct iphdr) <=
 118                     skb->tail)
 119                         return IP_ECN_set_ce(ip_hdr(skb));
 120                 break;
 121
 122         case __constant_htons(ETH_P_IPV6):
 123                 if (skb_network_header(skb) + sizeof(struct ipv6hdr) <=
 124                     skb->tail)
 125                         return IP6_ECN_set_ce(ipv6_hdr(skb));
 126                 break;
 127         }
 128
 129         return 0;
 130 }
 131
 132 #endif