1 /* $OpenBSD: tcp_subr.c,v 1.98 2007/06/25 12:17:43 markus Exp $ */ 2 /* $NetBSD: tcp_rndiss.c,v 1.4 2011/12/17 20:05:39 tls Exp $ */ 3 4 /* 5 * Copyright (c) 1982, 1986, 1988, 1990, 1993 6 * The Regents of the University of California. All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 * 32 * @(#)COPYRIGHT 1.1 (NRL) 17 January 1995 33 * 34 * NRL grants permission for redistribution and use in source and binary 35 * forms, with or without modification, of the software and documentation 36 * created at NRL provided that the following conditions are met: 37 * 38 * 1. Redistributions of source code must retain the above copyright 39 * notice, this list of conditions and the following disclaimer. 40 * 2. Redistributions in binary form must reproduce the above copyright 41 * notice, this list of conditions and the following disclaimer in the 42 * documentation and/or other materials provided with the distribution. 43 * 3. All advertising materials mentioning features or use of this software 44 * must display the following acknowledgements: 45 * This product includes software developed by the University of 46 * California, Berkeley and its contributors. 47 * This product includes software developed at the Information 48 * Technology Division, US Naval Research Laboratory. 49 * 4. Neither the name of the NRL nor the names of its contributors 50 * may be used to endorse or promote products derived from this software 51 * without specific prior written permission. 52 * 53 * THE SOFTWARE PROVIDED BY NRL IS PROVIDED BY NRL AND CONTRIBUTORS ``AS 54 * IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 55 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A 56 * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL NRL OR 57 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 58 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 59 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 60 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 61 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 62 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 63 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 64 * 65 * The views and conclusions contained in the software and documentation 66 * are those of the authors and should not be interpreted as representing 67 * official policies, either expressed or implied, of the US Naval 68 * Research Laboratory (NRL). 69 */ 70 71 #include <sys/cdefs.h> 72 __KERNEL_RCSID(0, "$NetBSD: tcp_rndiss.c,v 1.4 2011/12/17 20:05:39 tls Exp $"); 73 74 #include <sys/param.h> 75 #include <sys/cprng.h> 76 77 #include <netinet/tcp.h> 78 #include <netinet/tcp_seq.h> 79 #include <netinet/tcp_rndiss.h> 80 81 #define TCP_RNDISS_ROUNDS 16 82 #define TCP_RNDISS_OUT 7200 83 #define TCP_RNDISS_MAX 30000 84 85 u_int8_t tcp_rndiss_sbox[128]; 86 u_int16_t tcp_rndiss_msb; 87 u_int16_t tcp_rndiss_cnt; 88 long tcp_rndiss_reseed; 89 90 u_int16_t 91 tcp_rndiss_encrypt(u_int16_t val) 92 { 93 u_int16_t sum = 0, i; 94 95 for (i = 0; i < TCP_RNDISS_ROUNDS; i++) { 96 sum += 0x79b9; 97 val ^= ((u_int16_t)tcp_rndiss_sbox[(val^sum) & 0x7f]) << 7; 98 val = ((val & 0xff) << 7) | (val >> 8); 99 } 100 101 return val; 102 } 103 104 void 105 tcp_rndiss_init(void) 106 { 107 cprng_strong(kern_cprng, tcp_rndiss_sbox, sizeof(tcp_rndiss_sbox), 0); 108 109 tcp_rndiss_reseed = time_second + TCP_RNDISS_OUT; 110 tcp_rndiss_msb = tcp_rndiss_msb == 0x8000 ? 0 : 0x8000; 111 tcp_rndiss_cnt = 0; 112 } 113 114 tcp_seq 115 tcp_rndiss_next(void) 116 { 117 if (tcp_rndiss_cnt >= TCP_RNDISS_MAX || 118 time_second > tcp_rndiss_reseed) 119 tcp_rndiss_init(); 120 121 /* (arc4random() & 0x7fff) ensures a 32768 byte gap between ISS */ 122 return ((tcp_rndiss_encrypt(tcp_rndiss_cnt++) | tcp_rndiss_msb) <<16) | 123 (cprng_fast32() & 0x7fff); 124 } 125
Indexes created Sat Sep 20 22:09:52 GMT 2025