include/net/tcp_ecn.h

   1 #ifndef _NET_TCP_ECN_H_
   2 #define _NET_TCP_ECN_H_ 1
   3
   4 #include <net/inet_ecn.h>
   5 #include <net/request_sock.h>
   6
   7 #define TCP_HP_BITS (~(TCP_RESERVED_BITS|TCP_FLAG_PSH))
   8
   9 #define TCP_ECN_OK              1
  10 #define TCP_ECN_QUEUE_CWR       2
  11 #define TCP_ECN_DEMAND_CWR      4
  12
  13 static inline void TCP_ECN_queue_cwr(struct tcp_sock *tp)
  14 {
  15         if (tp->ecn_flags&TCP_ECN_OK)
  16                 tp->ecn_flags |= TCP_ECN_QUEUE_CWR;
  17 }
  18
  19
  20 /* Output functions */
  21
  22 static inline void TCP_ECN_send_synack(struct tcp_sock *tp,
  23                                        struct sk_buff *skb)
  24 {
  25         TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_CWR;
  26         if (!(tp->ecn_flags&TCP_ECN_OK))
  27                 TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_ECE;
  28 }
  29
  30 static inline void TCP_ECN_send_syn(struct sock *sk, struct tcp_sock *tp,
  31                                     struct sk_buff *skb)
  32 {
  33         tp->ecn_flags = 0;
  34         if (sysctl_tcp_ecn) {
  35                 TCP_SKB_CB(skb)->flags |= TCPCB_FLAG_ECE|TCPCB_FLAG_CWR;
  36                 tp->ecn_flags = TCP_ECN_OK;
  37         }
  38 }
  39
  40 static __inline__ void
  41 TCP_ECN_make_synack(struct request_sock *req, struct tcphdr *th)
  42 {
  43         if (inet_rsk(req)->ecn_ok)
  44                 th->ece = 1;
  45 }
  46
  47 static inline void TCP_ECN_send(struct sock *sk, struct tcp_sock *tp,
  48                                 struct sk_buff *skb, int tcp_header_len)
  49 {
  50         if (tp->ecn_flags & TCP_ECN_OK) {
  51                 /* Not-retransmitted data segment: set ECT and inject CWR. */
  52                 if (skb->len != tcp_header_len &&
  53                     !before(TCP_SKB_CB(skb)->seq, tp->snd_nxt)) {
  54                         INET_ECN_xmit(sk);
  55                         if (tp->ecn_flags&TCP_ECN_QUEUE_CWR) {
  56                                 tp->ecn_flags &= ~TCP_ECN_QUEUE_CWR;
  57                                 skb->h.th->cwr = 1;
  58                                 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
  59                         }
  60                 } else {
  61                         /* ACK or retransmitted segment: clear ECT|CE */
  62                         INET_ECN_dontxmit(sk);
  63                 }
  64                 if (tp->ecn_flags & TCP_ECN_DEMAND_CWR)
  65                         skb->h.th->ece = 1;
  66         }
  67 }
  68
  69 /* Input functions */
  70
  71 static inline void TCP_ECN_accept_cwr(struct tcp_sock *tp, struct sk_buff *skb)
  72 {
  73         if (skb->h.th->cwr)
  74                 tp->ecn_flags &= ~TCP_ECN_DEMAND_CWR;
  75 }
  76
  77 static inline void TCP_ECN_withdraw_cwr(struct tcp_sock *tp)
  78 {
  79         tp->ecn_flags &= ~TCP_ECN_DEMAND_CWR;
  80 }
  81
  82 static inline void TCP_ECN_check_ce(struct tcp_sock *tp, struct sk_buff *skb)
  83 {
  84         if (tp->ecn_flags&TCP_ECN_OK) {
  85                 if (INET_ECN_is_ce(TCP_SKB_CB(skb)->flags))
  86                         tp->ecn_flags |= TCP_ECN_DEMAND_CWR;
  87                 /* Funny extension: if ECT is not set on a segment,
  88                  * it is surely retransmit. It is not in ECN RFC,
  89                  * but Linux follows this rule. */
  90                 else if (INET_ECN_is_not_ect((TCP_SKB_CB(skb)->flags)))
  91                         tcp_enter_quickack_mode((struct sock *)tp);
  92         }
  93 }
  94
  95 static inline void TCP_ECN_rcv_synack(struct tcp_sock *tp, struct tcphdr *th)
  96 {
  97         if ((tp->ecn_flags&TCP_ECN_OK) && (!th->ece || th->cwr))
  98                 tp->ecn_flags &= ~TCP_ECN_OK;
  99 }
 100
 101 static inline void TCP_ECN_rcv_syn(struct tcp_sock *tp, struct tcphdr *th)
 102 {
 103         if ((tp->ecn_flags&TCP_ECN_OK) && (!th->ece || !th->cwr))
 104                 tp->ecn_flags &= ~TCP_ECN_OK;
 105 }
 106
 107 static inline int TCP_ECN_rcv_ecn_echo(struct tcp_sock *tp, struct tcphdr *th)
 108 {
 109         if (th->ece && !th->syn && (tp->ecn_flags&TCP_ECN_OK))
 110                 return 1;
 111         return 0;
 112 }
 113
 114 static inline void TCP_ECN_openreq_child(struct tcp_sock *tp,
 115                                          struct request_sock *req)
 116 {
 117         tp->ecn_flags = inet_rsk(req)->ecn_ok ? TCP_ECN_OK : 0;
 118 }
 119
 120 static __inline__ void
 121 TCP_ECN_create_request(struct request_sock *req, struct tcphdr *th)
 122 {
 123         if (sysctl_tcp_ecn && th->ece && th->cwr)
 124                 inet_rsk(req)->ecn_ok = 1;
 125 }
 126
 127 #endif