| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * Various handy server-only utilities |
| 4 | * |
| 5 | * (c) 2001 Straylight/Edgeware |
| 6 | */ |
| 7 | |
| 8 | /*----- Licensing notice --------------------------------------------------* |
| 9 | * |
| 10 | * This file is part of Trivial IP Encryption (TrIPE). |
| 11 | * |
| 12 | * TrIPE is free software: you can redistribute it and/or modify it under |
| 13 | * the terms of the GNU General Public License as published by the Free |
| 14 | * Software Foundation; either version 3 of the License, or (at your |
| 15 | * option) any later version. |
| 16 | * |
| 17 | * TrIPE is distributed in the hope that it will be useful, but WITHOUT |
| 18 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 19 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 20 | * for more details. |
| 21 | * |
| 22 | * You should have received a copy of the GNU General Public License |
| 23 | * along with TrIPE. If not, see <https://www.gnu.org/licenses/>. |
| 24 | */ |
| 25 | |
| 26 | /*----- Header files ------------------------------------------------------*/ |
| 27 | |
| 28 | #include "tripe.h" |
| 29 | |
| 30 | /*----- Global variables --------------------------------------------------*/ |
| 31 | |
| 32 | octet buf_i[PKBUFSZ], buf_o[PKBUFSZ], buf_t[PKBUFSZ], buf_u[PKBUFSZ]; |
| 33 | |
| 34 | /*----- Sequence numbers --------------------------------------------------*/ |
| 35 | |
| 36 | /* --- @seq_reset@ --- * |
| 37 | * |
| 38 | * Arguments: @seqwin *s@ = sequence-checking window |
| 39 | * |
| 40 | * Returns: --- |
| 41 | * |
| 42 | * Use: Resets a sequence number window. |
| 43 | */ |
| 44 | |
| 45 | void seq_reset(seqwin *s) { s->seq = 0; s->win = 0; } |
| 46 | |
| 47 | /* --- @seq_check@ --- * |
| 48 | * |
| 49 | * Arguments: @seqwin *s@ = sequence-checking window |
| 50 | * @uint32 q@ = sequence number to check |
| 51 | * @const char *service@ = service to report message from |
| 52 | * |
| 53 | * Returns: Zero on success, nonzero if the sequence number was bad. |
| 54 | * |
| 55 | * Use: Checks a sequence number against the window, updating things |
| 56 | * as necessary. |
| 57 | */ |
| 58 | |
| 59 | int seq_check(seqwin *s, uint32 q, const char *service) |
| 60 | { |
| 61 | uint32 qbit; |
| 62 | uint32 n; |
| 63 | |
| 64 | if (q < s->seq) { |
| 65 | a_warn(service, "replay", "old-sequence", A_END); |
| 66 | return (-1); |
| 67 | } |
| 68 | if (q >= s->seq + SEQ_WINSZ) { |
| 69 | n = q - (s->seq + SEQ_WINSZ - 1); |
| 70 | if (n < SEQ_WINSZ) |
| 71 | s->win >>= n; |
| 72 | else |
| 73 | s->win = 0; |
| 74 | s->seq += n; |
| 75 | } |
| 76 | qbit = 1 << (q - s->seq); |
| 77 | if (s->win & qbit) { |
| 78 | a_warn(service, "replay", "duplicated-sequence", A_END); |
| 79 | return (-1); |
| 80 | } |
| 81 | s->win |= qbit; |
| 82 | return (0); |
| 83 | } |
| 84 | |
| 85 | /*----- Rate limiting -----------------------------------------------------*/ |
| 86 | |
| 87 | /* --- @ratelim_init@ --- * |
| 88 | * |
| 89 | * Arguments: @ratelim *r@ = rate-limiting state to fill in |
| 90 | * @unsigned persec@ = credit to accumulate per second |
| 91 | * @unsigned max@ = maximum credit to retain |
| 92 | * |
| 93 | * Returns: --- |
| 94 | * |
| 95 | * Use: Initialize a rate-limiting state. |
| 96 | */ |
| 97 | |
| 98 | void ratelim_init(ratelim *r, unsigned persec, unsigned max) |
| 99 | { |
| 100 | r->n = r->max = max; |
| 101 | r->persec = persec; |
| 102 | gettimeofday(&r->when, 0); |
| 103 | } |
| 104 | |
| 105 | /* --- @ratelim_withdraw@ --- * |
| 106 | * |
| 107 | * Arguments: @ratelim *r@ = rate-limiting state |
| 108 | * @unsigned n@ = credit to withdraw |
| 109 | * |
| 110 | * Returns: Zero if successful; @-1@ if there is unsufficient credit |
| 111 | * |
| 112 | * Use: Updates the state with any accumulated credit. Then, if |
| 113 | * there there are more than @n@ credits available, withdraw @n@ |
| 114 | * and return successfully; otherwise, report failure. |
| 115 | */ |
| 116 | |
| 117 | int ratelim_withdraw(ratelim *r, unsigned n) |
| 118 | { |
| 119 | struct timeval now, delta; |
| 120 | unsigned long d; |
| 121 | |
| 122 | gettimeofday(&now, 0); |
| 123 | TV_SUB(&delta, &now, &r->when); |
| 124 | d = (unsigned long)r->persec*delta.tv_sec + |
| 125 | (unsigned long)r->persec*delta.tv_usec/MILLION; |
| 126 | if (d < r->max - r->n) r->n += d; |
| 127 | else r->n = r->max; |
| 128 | r->when = now; |
| 129 | |
| 130 | if (n > r->n) return (-1); |
| 131 | else { r->n -= n; return (0); } |
| 132 | } |
| 133 | |
| 134 | /*----- Random odds and sods ----------------------------------------------*/ |
| 135 | |
| 136 | /* --- @timestr@ --- * |
| 137 | * |
| 138 | * Arguments: @time_t t@ = a time to convert |
| 139 | * |
| 140 | * Returns: A pointer to a textual representation of the time. |
| 141 | * |
| 142 | * Use: Converts a time to a textual representation. Corrupts |
| 143 | * @buf_u@. |
| 144 | */ |
| 145 | |
| 146 | const char *timestr(time_t t) |
| 147 | { |
| 148 | struct tm *tm; |
| 149 | if (!t) |
| 150 | return ("NEVER"); |
| 151 | tm = localtime(&t); |
| 152 | strftime((char *)buf_u, sizeof(buf_u), "%Y-%m-%dT%H:%M:%S", tm); |
| 153 | return ((const char *)buf_u); |
| 154 | } |
| 155 | |
| 156 | /* --- @mystrieq@ --- * |
| 157 | * |
| 158 | * Arguments: @const char *x, *y@ = two strings |
| 159 | * |
| 160 | * Returns: True if @x@ and @y are equal, up to case. |
| 161 | */ |
| 162 | |
| 163 | int mystrieq(const char *x, const char *y) |
| 164 | { |
| 165 | for (;;) { |
| 166 | if (!*x && !*y) return (1); |
| 167 | if (tolower((unsigned char)*x) != tolower((unsigned char)*y)) |
| 168 | return (0); |
| 169 | x++; y++; |
| 170 | } |
| 171 | } |
| 172 | |
| 173 | /* --- @addrsz@ --- * |
| 174 | * |
| 175 | * Arguments: @const addr *a@ = a network address |
| 176 | * |
| 177 | * Returns: The size of the address, for passing into the sockets API. |
| 178 | */ |
| 179 | |
| 180 | socklen_t addrsz(const addr *a) |
| 181 | { |
| 182 | switch (a->sa.sa_family) { |
| 183 | case AF_INET: return (sizeof(a->sin)); |
| 184 | default: abort(); |
| 185 | } |
| 186 | } |
| 187 | |
| 188 | /*----- That's all, folks -------------------------------------------------*/ |