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 #include <net/dsfield.h>
   7
   8 enum {
   9         INET_ECN_NOT_ECT = 0,
  10         INET_ECN_ECT_1 = 1,
  11         INET_ECN_ECT_0 = 2,
  12         INET_ECN_CE = 3,
  13         INET_ECN_MASK = 3,
  14 };
  15
  16 static inline int INET_ECN_is_ce(__u8 dsfield)
  17 {
  18         return (dsfield & INET_ECN_MASK) == INET_ECN_CE;
  19 }
  20
  21 static inline int INET_ECN_is_not_ect(__u8 dsfield)
  22 {
  23         return (dsfield & INET_ECN_MASK) == INET_ECN_NOT_ECT;
  24 }
  25
  26 static inline int INET_ECN_is_capable(__u8 dsfield)
  27 {
  28         return (dsfield & INET_ECN_ECT_0);
  29 }
  30
  31 static inline __u8 INET_ECN_encapsulate(__u8 outer, __u8 inner)
  32 {
  33         outer &= ~INET_ECN_MASK;
  34         outer |= !INET_ECN_is_ce(inner) ? (inner & INET_ECN_MASK) :
  35                                           INET_ECN_ECT_0;
  36         return outer;
  37 }
  38
  39 #define INET_ECN_xmit(sk) do { inet_sk(sk)->tos |= INET_ECN_ECT_0; } while (0)
  40 #define INET_ECN_dontxmit(sk) \
  41         do { inet_sk(sk)->tos &= ~INET_ECN_MASK; } while (0)
  42
  43 #define IP6_ECN_flow_init(label) do {           \
  44       (label) &= ~htonl(INET_ECN_MASK << 20);   \
  45     } while (0)
  46
  47 #define IP6_ECN_flow_xmit(sk, label) do {                               \
  48         if (INET_ECN_is_capable(inet_sk(sk)->tos))                      \
  49                 (label) |= __constant_htons(INET_ECN_ECT_0 << 4);       \
  50     } while (0)
  51
  52 static inline int IP_ECN_set_ce(struct iphdr *iph)
  53 {
  54         u32 check = iph->check;
  55         u32 ecn = (iph->tos + 1) & INET_ECN_MASK;
  56
  57         /*
  58          * After the last operation we have (in binary):
  59          * INET_ECN_NOT_ECT => 01
  60          * INET_ECN_ECT_1   => 10
  61          * INET_ECN_ECT_0   => 11
  62          * INET_ECN_CE      => 00
  63          */
  64         if (!(ecn & 2))
  65                 return !ecn;
  66
  67         /*
  68          * The following gives us:
  69          * INET_ECN_ECT_1 => check += htons(0xFFFD)
  70          * INET_ECN_ECT_0 => check += htons(0xFFFE)
  71          */
  72         check += htons(0xFFFB) + htons(ecn);
  73
  74         iph->check = check + (check>=0xFFFF);
  75         iph->tos |= INET_ECN_CE;
  76         return 1;
  77 }
  78
  79 static inline void IP_ECN_clear(struct iphdr *iph)
  80 {
  81         iph->tos &= ~INET_ECN_MASK;
  82 }
  83
  84 static inline void ipv4_copy_dscp(struct iphdr *outer, struct iphdr *inner)
  85 {
  86         u32 dscp = ipv4_get_dsfield(outer) & ~INET_ECN_MASK;
  87         ipv4_change_dsfield(inner, INET_ECN_MASK, dscp);
  88 }
  89
  90 struct ipv6hdr;
  91
  92 static inline int IP6_ECN_set_ce(struct ipv6hdr *iph)
  93 {
  94         if (INET_ECN_is_not_ect(ipv6_get_dsfield(iph)))
  95                 return 0;
  96         *(u32*)iph |= htonl(INET_ECN_CE << 20);
  97         return 1;
  98 }
  99
 100 static inline void IP6_ECN_clear(struct ipv6hdr *iph)
 101 {
 102         *(u32*)iph &= ~htonl(INET_ECN_MASK << 20);
 103 }
 104
 105 static inline void ipv6_copy_dscp(struct ipv6hdr *outer, struct ipv6hdr *inner)
 106 {
 107         u32 dscp = ipv6_get_dsfield(outer) & ~INET_ECN_MASK;
 108         ipv6_change_dsfield(inner, INET_ECN_MASK, dscp);
 109 }
 110
 111 static inline int INET_ECN_set_ce(struct sk_buff *skb)
 112 {
 113         switch (skb->protocol) {
 114         case __constant_htons(ETH_P_IP):
 115                 if (skb->nh.raw + sizeof(struct iphdr) <= skb->tail)
 116                         return IP_ECN_set_ce(skb->nh.iph);
 117                 break;
 118
 119         case __constant_htons(ETH_P_IPV6):
 120                 if (skb->nh.raw + sizeof(struct ipv6hdr) <= skb->tail)
 121                         return IP6_ECN_set_ce(skb->nh.ipv6h);
 122                 break;
 123         }
 124
 125         return 0;
 126 }
 127
 128 #endif