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_opt * tp)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
TCP_ECN_send_synack(struct tcp_opt * tp,struct sk_buff * skb)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
TCP_ECN_send_syn(struct tcp_opt * tp,struct sk_buff * skb)31 TCP_ECN_send_syn(struct tcp_opt *tp, 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
TCP_ECN_make_synack(struct open_request * req,struct tcphdr * th)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_opt * tp,struct sk_buff * skb,int tcp_header_len)48 TCP_ECN_send(struct sock *sk, struct tcp_opt *tp, 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_opt * tp,struct sk_buff * skb)71 TCP_ECN_accept_cwr(struct tcp_opt *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_opt * tp)78 TCP_ECN_withdraw_cwr(struct tcp_opt *tp)
79 {
80 tp->ecn_flags &= ~TCP_ECN_DEMAND_CWR;
81 }
82
83 static __inline__ void
TCP_ECN_check_ce(struct tcp_opt * tp,struct sk_buff * skb)84 TCP_ECN_check_ce(struct tcp_opt *tp, struct sk_buff *skb)
85 {
86 if (tp->ecn_flags&TCP_ECN_OK) {
87 if (INET_ECN_is_ce(TCP_SKB_CB(skb)->flags))
88 tp->ecn_flags |= TCP_ECN_DEMAND_CWR;
89 /* Funny extension: if ECT is not set on a segment,
90 * it is surely retransmit. It is not in ECN RFC,
91 * but Linux follows this rule. */
92 else if (!INET_ECN_is_capable((TCP_SKB_CB(skb)->flags)))
93 tcp_enter_quickack_mode(tp);
94 }
95 }
96
97 static __inline__ void
TCP_ECN_rcv_synack(struct tcp_opt * tp,struct tcphdr * th)98 TCP_ECN_rcv_synack(struct tcp_opt *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_opt * tp,struct tcphdr * th)105 TCP_ECN_rcv_syn(struct tcp_opt *tp, struct tcphdr *th)
106 {
107 if ((tp->ecn_flags&TCP_ECN_OK) && (!th->ece || !th->cwr))
108 tp->ecn_flags &= ~TCP_ECN_OK;
109 }
110
111 static __inline__ int
TCP_ECN_rcv_ecn_echo(struct tcp_opt * tp,struct tcphdr * th)112 TCP_ECN_rcv_ecn_echo(struct tcp_opt *tp, struct tcphdr *th)
113 {
114 if (th->ece && !th->syn && (tp->ecn_flags&TCP_ECN_OK))
115 return 1;
116 return 0;
117 }
118
119 static __inline__ void
TCP_ECN_openreq_child(struct tcp_opt * tp,struct open_request * req)120 TCP_ECN_openreq_child(struct tcp_opt *tp, struct open_request *req)
121 {
122 tp->ecn_flags = req->ecn_ok ? TCP_ECN_OK : 0;
123 }
124
125 static __inline__ void
TCP_ECN_create_request(struct open_request * req,struct tcphdr * th)126 TCP_ECN_create_request(struct open_request *req, struct tcphdr *th)
127 {
128 if (sysctl_tcp_ecn && th->ece && th->cwr)
129 req->ecn_ok = 1;
130 }
131
132 #endif
133