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
  13 TCP_ECN_queue_cwr(struct tcp_opt *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
  23 TCP_ECN_send_synack(struct tcp_opt *tp, 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
  31 TCP_ECN_send_syn(struct sock *sk, struct tcp_opt *tp, struct sk_buff *skb)
  32 {
  33         tp->ecn_flags = 0;
  34         if (sysctl_tcp_ecn && !(sk->sk_route_caps & NETIF_F_TSO)) {
  35                 TCP_SKB_CB(skb)->flags |= TCPCB_FLAG_ECE|TCPCB_FLAG_CWR;
  36                 tp->ecn_flags = TCP_ECN_OK;
  37                 sk->sk_no_largesend = 1;
  38         }
  39 }
  40
  41 static __inline__ void
  42 TCP_ECN_make_synack(struct open_request *req, struct tcphdr *th)
  43 {
  44         if (req->ecn_ok)
  45                 th->ece = 1;
  46 }
  47
  48 static __inline__ void
  49 TCP_ECN_send(struct sock *sk, struct tcp_opt *tp, struct sk_buff *skb, int tcp_header_len)
  50 {
  51         if (tp->ecn_flags & TCP_ECN_OK) {
  52                 /* Not-retransmitted data segment: set ECT and inject CWR. */
  53                 if (skb->len != tcp_header_len &&
  54                     !before(TCP_SKB_CB(skb)->seq, tp->snd_nxt)) {
  55                         INET_ECN_xmit(sk);
  56                         if (tp->ecn_flags&TCP_ECN_QUEUE_CWR) {
  57                                 tp->ecn_flags &= ~TCP_ECN_QUEUE_CWR;
  58                                 skb->h.th->cwr = 1;
  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
  72 TCP_ECN_accept_cwr(struct tcp_opt *tp, struct sk_buff *skb)
  73 {
  74         if (skb->h.th->cwr)
  75                 tp->ecn_flags &= ~TCP_ECN_DEMAND_CWR;
  76 }
  77
  78 static __inline__ void
  79 TCP_ECN_withdraw_cwr(struct tcp_opt *tp)
  80 {
  81         tp->ecn_flags &= ~TCP_ECN_DEMAND_CWR;
  82 }
  83
  84 static __inline__ void
  85 TCP_ECN_check_ce(struct tcp_opt *tp, struct sk_buff *skb)
  86 {
  87         if (tp->ecn_flags&TCP_ECN_OK) {
  88                 if (INET_ECN_is_ce(TCP_SKB_CB(skb)->flags))
  89                         tp->ecn_flags |= TCP_ECN_DEMAND_CWR;
  90                 /* Funny extension: if ECT is not set on a segment,
  91                  * it is surely retransmit. It is not in ECN RFC,
  92                  * but Linux follows this rule. */
  93                 else if (INET_ECN_is_not_ect((TCP_SKB_CB(skb)->flags)))
  94                         tcp_enter_quickack_mode(tp);
  95         }
  96 }
  97
  98 static __inline__ void
  99 TCP_ECN_rcv_synack(struct tcp_opt *tp, struct tcphdr *th)
 100 {
 101         if ((tp->ecn_flags&TCP_ECN_OK) && (!th->ece || th->cwr))
 102                 tp->ecn_flags &= ~TCP_ECN_OK;
 103 }
 104
 105 static __inline__ void
 106 TCP_ECN_rcv_syn(struct tcp_opt *tp, struct tcphdr *th)
 107 {
 108         if ((tp->ecn_flags&TCP_ECN_OK) && (!th->ece || !th->cwr))
 109                 tp->ecn_flags &= ~TCP_ECN_OK;
 110 }
 111
 112 static __inline__ int
 113 TCP_ECN_rcv_ecn_echo(struct tcp_opt *tp, struct tcphdr *th)
 114 {
 115         if (th->ece && !th->syn && (tp->ecn_flags&TCP_ECN_OK))
 116                 return 1;
 117         return 0;
 118 }
 119
 120 static __inline__ void
 121 TCP_ECN_openreq_child(struct tcp_opt *tp, struct open_request *req)
 122 {
 123         tp->ecn_flags = req->ecn_ok ? TCP_ECN_OK : 0;
 124 }
 125
 126 static __inline__ void
 127 TCP_ECN_create_request(struct open_request *req, struct tcphdr *th)
 128 {
 129         if (sysctl_tcp_ecn && th->ece && th->cwr)
 130                 req->ecn_ok = 1;
 131 }
 132
 133 #endif