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 sk_buff *skb)
  31 {
  32         struct tcp_sock *tp = tcp_sk(sk);
  33
  34         tp->ecn_flags = 0;
  35         if (sysctl_tcp_ecn) {
  36                 TCP_SKB_CB(skb)->flags |= TCPCB_FLAG_ECE|TCPCB_FLAG_CWR;
  37                 tp->ecn_flags = TCP_ECN_OK;
  38         }
  39 }
  40
  41 static __inline__ void
  42 TCP_ECN_make_synack(struct request_sock *req, struct tcphdr *th)
  43 {
  44         if (inet_rsk(req)->ecn_ok)
  45                 th->ece = 1;
  46 }
  47
  48 static inline void TCP_ECN_send(struct sock *sk, struct sk_buff *skb,
  49                                 int tcp_header_len)
  50 {
  51         struct tcp_sock *tp = tcp_sk(sk);
  52
  53         if (tp->ecn_flags & TCP_ECN_OK) {
  54                 /* Not-retransmitted data segment: set ECT and inject CWR. */
  55                 if (skb->len != tcp_header_len &&
  56                     !before(TCP_SKB_CB(skb)->seq, tp->snd_nxt)) {
  57                         INET_ECN_xmit(sk);
  58                         if (tp->ecn_flags&TCP_ECN_QUEUE_CWR) {
  59                                 tp->ecn_flags &= ~TCP_ECN_QUEUE_CWR;
  60                                 tcp_hdr(skb)->cwr = 1;
  61                                 skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
  62                         }
  63                 } else {
  64                         /* ACK or retransmitted segment: clear ECT|CE */
  65                         INET_ECN_dontxmit(sk);
  66                 }
  67                 if (tp->ecn_flags & TCP_ECN_DEMAND_CWR)
  68                         tcp_hdr(skb)->ece = 1;
  69         }
  70 }
  71
  72 /* Input functions */
  73
  74 static inline void TCP_ECN_accept_cwr(struct tcp_sock *tp, struct sk_buff *skb)
  75 {
  76         if (tcp_hdr(skb)->cwr)
  77                 tp->ecn_flags &= ~TCP_ECN_DEMAND_CWR;
  78 }
  79
  80 static inline void TCP_ECN_withdraw_cwr(struct tcp_sock *tp)
  81 {
  82         tp->ecn_flags &= ~TCP_ECN_DEMAND_CWR;
  83 }
  84
  85 static inline void TCP_ECN_check_ce(struct tcp_sock *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((struct sock *)tp);
  95         }
  96 }
  97
  98 static inline void TCP_ECN_rcv_synack(struct tcp_sock *tp, struct tcphdr *th)
  99 {
 100         if ((tp->ecn_flags&TCP_ECN_OK) && (!th->ece || th->cwr))
 101                 tp->ecn_flags &= ~TCP_ECN_OK;
 102 }
 103
 104 static inline void TCP_ECN_rcv_syn(struct tcp_sock *tp, struct tcphdr *th)
 105 {
 106         if ((tp->ecn_flags&TCP_ECN_OK) && (!th->ece || !th->cwr))
 107                 tp->ecn_flags &= ~TCP_ECN_OK;
 108 }
 109
 110 static inline int TCP_ECN_rcv_ecn_echo(struct tcp_sock *tp, struct tcphdr *th)
 111 {
 112         if (th->ece && !th->syn && (tp->ecn_flags&TCP_ECN_OK))
 113                 return 1;
 114         return 0;
 115 }
 116
 117 static inline void TCP_ECN_openreq_child(struct tcp_sock *tp,
 118                                          struct request_sock *req)
 119 {
 120         tp->ecn_flags = inet_rsk(req)->ecn_ok ? TCP_ECN_OK : 0;
 121 }
 122
 123 static __inline__ void
 124 TCP_ECN_create_request(struct request_sock *req, struct tcphdr *th)
 125 {
 126         if (sysctl_tcp_ecn && th->ece && th->cwr)
 127                 inet_rsk(req)->ecn_ok = 1;
 128 }
 129
 130 #endif