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