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 static inline void INET_ECN_xmit(struct sock *sk)
  42 {
  43         inet_sk(sk)->tos |= INET_ECN_ECT_0;
  44         if (inet6_sk(sk) != NULL)
  45                 inet6_sk(sk)->tclass |= INET_ECN_ECT_0;
  46 }
  47
  48 static inline void INET_ECN_dontxmit(struct sock *sk)
  49 {
  50         inet_sk(sk)->tos &= ~INET_ECN_MASK;
  51         if (inet6_sk(sk) != NULL)
  52                 inet6_sk(sk)->tclass &= ~INET_ECN_MASK;
  53 }
  54
  55 #define IP6_ECN_flow_init(label) do {           \
  56       (label) &= ~htonl(INET_ECN_MASK << 20);   \
  57     } while (0)
  58
  59 #define IP6_ECN_flow_xmit(sk, label) do {                               \
  60         if (INET_ECN_is_capable(inet6_sk(sk)->tclass))                  \
  61                 (label) |= htonl(INET_ECN_ECT_0 << 20);                 \
  62     } while (0)
  63
  64 static inline int IP_ECN_set_ce(struct iphdr *iph)
  65 {
  66         u32 check = (__force u32)iph->check;
  67         u32 ecn = (iph->tos + 1) & INET_ECN_MASK;
  68
  69         /*
  70          * After the last operation we have (in binary):
  71          * INET_ECN_NOT_ECT => 01
  72          * INET_ECN_ECT_1   => 10
  73          * INET_ECN_ECT_0   => 11
  74          * INET_ECN_CE      => 00
  75          */
  76         if (!(ecn & 2))
  77                 return !ecn;
  78
  79         /*
  80          * The following gives us:
  81          * INET_ECN_ECT_1 => check += htons(0xFFFD)
  82          * INET_ECN_ECT_0 => check += htons(0xFFFE)
  83          */
  84         check += (__force u16)htons(0xFFFB) + (__force u16)htons(ecn);
  85
  86         iph->check = (__force __sum16)(check + (check>=0xFFFF));
  87         iph->tos |= INET_ECN_CE;
  88         return 1;
  89 }
  90
  91 static inline void IP_ECN_clear(struct iphdr *iph)
  92 {
  93         iph->tos &= ~INET_ECN_MASK;
  94 }
  95
  96 static inline void ipv4_copy_dscp(unsigned int dscp, struct iphdr *inner)
  97 {
  98         dscp &= ~INET_ECN_MASK;
  99         ipv4_change_dsfield(inner, INET_ECN_MASK, dscp);
 100 }
 101
 102 struct ipv6hdr;
 103
 104 static inline int IP6_ECN_set_ce(struct ipv6hdr *iph)
 105 {
 106         if (INET_ECN_is_not_ect(ipv6_get_dsfield(iph)))
 107                 return 0;
 108         *(__be32*)iph |= htonl(INET_ECN_CE << 20);
 109         return 1;
 110 }
 111
 112 static inline void IP6_ECN_clear(struct ipv6hdr *iph)
 113 {
 114         *(__be32*)iph &= ~htonl(INET_ECN_MASK << 20);
 115 }
 116
 117 static inline void ipv6_copy_dscp(unsigned int dscp, struct ipv6hdr *inner)
 118 {
 119         dscp &= ~INET_ECN_MASK;
 120         ipv6_change_dsfield(inner, INET_ECN_MASK, dscp);
 121 }
 122
 123 static inline int INET_ECN_set_ce(struct sk_buff *skb)
 124 {
 125         switch (skb->protocol) {
 126         case cpu_to_be16(ETH_P_IP):
 127                 if (skb->network_header + sizeof(struct iphdr) <= skb->tail)
 128                         return IP_ECN_set_ce(ip_hdr(skb));
 129                 break;
 130
 131         case cpu_to_be16(ETH_P_IPV6):
 132                 if (skb->network_header + sizeof(struct ipv6hdr) <= skb->tail)
 133                         return IP6_ECN_set_ce(ipv6_hdr(skb));
 134                 break;
 135         }
 136
 137         return 0;
 138 }
 139
 140 #endif