include/net/inet_ecn.h

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