syncookies.c (73ed8e03388d16c12fc577e5c700b58a29045a15) syncookies.c (003e07a1e48e9423647d2fef1c86b4caab3a94be)
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Syncookies implementation for the Linux kernel
4 *
5 * Copyright (C) 1997 Andi Kleen
6 * Based on ideas by D.J.Bernstein and Eric Schenk.
7 */
8

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46 u32 count, int c)
47{
48 net_get_random_once(syncookie_secret, sizeof(syncookie_secret));
49 return siphash_4u32((__force u32)saddr, (__force u32)daddr,
50 (__force u32)sport << 16 | (__force u32)dport,
51 count, &syncookie_secret[c]);
52}
53
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Syncookies implementation for the Linux kernel
4 *
5 * Copyright (C) 1997 Andi Kleen
6 * Based on ideas by D.J.Bernstein and Eric Schenk.
7 */
8

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46 u32 count, int c)
47{
48 net_get_random_once(syncookie_secret, sizeof(syncookie_secret));
49 return siphash_4u32((__force u32)saddr, (__force u32)daddr,
50 (__force u32)sport << 16 | (__force u32)dport,
51 count, &syncookie_secret[c]);
52}
53
54/* Convert one nsec 64bit timestamp to ts (ms or usec resolution) */
55static u64 tcp_ns_to_ts(bool usec_ts, u64 val)
56{
57 if (usec_ts)
58 return div_u64(val, NSEC_PER_USEC);
54
59
60 return div_u64(val, NSEC_PER_MSEC);
61}
62
55/*
56 * when syncookies are in effect and tcp timestamps are enabled we encode
57 * tcp options in the lower bits of the timestamp value that will be
58 * sent in the syn-ack.
59 * Since subsequent timestamps use the normal tcp_time_stamp value, we
60 * must make sure that the resulting initial timestamp is <= tcp_time_stamp.
61 */
62u64 cookie_init_timestamp(struct request_sock *req, u64 now)
63{
64 const struct inet_request_sock *ireq = inet_rsk(req);
63/*
64 * when syncookies are in effect and tcp timestamps are enabled we encode
65 * tcp options in the lower bits of the timestamp value that will be
66 * sent in the syn-ack.
67 * Since subsequent timestamps use the normal tcp_time_stamp value, we
68 * must make sure that the resulting initial timestamp is <= tcp_time_stamp.
69 */
70u64 cookie_init_timestamp(struct request_sock *req, u64 now)
71{
72 const struct inet_request_sock *ireq = inet_rsk(req);
65 u64 ts, ts_now = tcp_ns_to_ts(now);
73 u64 ts, ts_now = tcp_ns_to_ts(false, now);
66 u32 options = 0;
67
68 options = ireq->wscale_ok ? ireq->snd_wscale : TS_OPT_WSCALE_MASK;
69 if (ireq->sack_ok)
70 options |= TS_OPT_SACK;
71 if (ireq->ecn_ok)
72 options |= TS_OPT_ECN;
73

--- 376 unchanged lines hidden --- 		74 u32 options = 0;
75
76 options = ireq->wscale_ok ? ireq->snd_wscale : TS_OPT_WSCALE_MASK;
77 if (ireq->sack_ok)
78 options |= TS_OPT_SACK;
79 if (ireq->ecn_ok)
80 options |= TS_OPT_ECN;
81

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