| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * Hashtables keyed by network addresses |
| 4 | * |
| 5 | * (c) 2007 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 | #define AM_LOAD(n) (((n) * 3)/2) |
| 31 | |
| 32 | /*----- Main code ---------------------------------------------------------*/ |
| 33 | |
| 34 | /* --- @am_create@ --- * |
| 35 | * |
| 36 | * Arguments: @addrmap *m@ = pointer to map |
| 37 | * |
| 38 | * Returns: --- |
| 39 | * |
| 40 | * Use: Create an address map, properly set up. |
| 41 | */ |
| 42 | |
| 43 | void am_create(addrmap *m) |
| 44 | { |
| 45 | hash_create(&m->t, 16); |
| 46 | m->load = AM_LOAD(m->t.mask + 1); |
| 47 | } |
| 48 | |
| 49 | /* --- @am_destroy@ --- * |
| 50 | * |
| 51 | * Arguments: @addrmap *m@ = pointer to map |
| 52 | * |
| 53 | * Returns: --- |
| 54 | * |
| 55 | * Use: Destroy an address map, throwing away all the entries. |
| 56 | */ |
| 57 | |
| 58 | void am_destroy(addrmap *m) |
| 59 | { |
| 60 | hash_base *p; |
| 61 | hash_iter i; |
| 62 | |
| 63 | for (hash_mkiter(&i, &m->t); (p = hash_next(&i)) != 0; ) |
| 64 | x_free(m->t.a, p); |
| 65 | hash_destroy(&m->t); |
| 66 | } |
| 67 | |
| 68 | /* --- @hash@ --- * |
| 69 | * |
| 70 | * Arguments: @const addr *a@ = pointer to address |
| 71 | * |
| 72 | * Returns: The hash of the address. |
| 73 | */ |
| 74 | |
| 75 | static uint32 hash(const addr *a) |
| 76 | { |
| 77 | switch (a->sa.sa_family) { |
| 78 | case AF_INET: |
| 79 | return (U32((AF_INET * 0x4eaac1b7ul) + |
| 80 | (a->sin.sin_addr.s_addr * 0xa5dbc837) + |
| 81 | (a->sin.sin_port * 0x3b049e83))); |
| 82 | default: |
| 83 | abort(); |
| 84 | } |
| 85 | } |
| 86 | |
| 87 | /* --- @addreq@ --- * |
| 88 | * |
| 89 | * Arguments: @const addr *a, *b@ = pointer to addresses |
| 90 | * |
| 91 | * Returns: Nonzero if the addresses are equal. |
| 92 | */ |
| 93 | |
| 94 | static int addreq(const addr *a, const addr *b) |
| 95 | { |
| 96 | if (a->sa.sa_family != b->sa.sa_family) |
| 97 | return (0); |
| 98 | switch (a->sa.sa_family) { |
| 99 | case AF_INET: |
| 100 | return (a->sin.sin_addr.s_addr == b->sin.sin_addr.s_addr && |
| 101 | a->sin.sin_port == b->sin.sin_port); |
| 102 | default: |
| 103 | abort(); |
| 104 | } |
| 105 | } |
| 106 | |
| 107 | /* --- @am_find@ --- * |
| 108 | * |
| 109 | * Arguments: @addrmap *m@ = pointer to map |
| 110 | * @const addr *a@ = address to look up |
| 111 | * @size_t sz@ = size of block to allocate |
| 112 | * @unsigned *f@ = where to store flags |
| 113 | * |
| 114 | * Returns: Pointer to found item, or null. |
| 115 | * |
| 116 | * Use: Finds a record with the given IP address, set @*f@ nonzero |
| 117 | * and returns it. If @sz@ is zero, and no match was found, |
| 118 | * return null; otherwise allocate a new block of @sz@ bytes, |
| 119 | * clear @*f@ to zero and return the block pointer. |
| 120 | */ |
| 121 | |
| 122 | void *am_find(addrmap *m, const addr *a, size_t sz, unsigned *f) |
| 123 | { |
| 124 | uint32 h = hash(a); |
| 125 | hash_base **b, **bb; |
| 126 | addrmap_base *i; |
| 127 | |
| 128 | bb = HASH_BIN(&m->t, h); |
| 129 | for (b = bb; *b; b = &(*b)->next) { |
| 130 | i = (addrmap_base *)*b; |
| 131 | if (i->b.hash == h && addreq(a, &i->a)) { |
| 132 | *b = i->b.next; |
| 133 | i->b.next = *bb; |
| 134 | *bb = &i->b; |
| 135 | if (f) *f = 1; |
| 136 | return (i); |
| 137 | } |
| 138 | } |
| 139 | |
| 140 | if (f) *f = 0; |
| 141 | if (!sz) return (0); |
| 142 | i = x_alloc(m->t.a, sz); |
| 143 | i->b.hash = h; |
| 144 | i->b.next = *bb; |
| 145 | *bb = &i->b; |
| 146 | i->a = *a; |
| 147 | |
| 148 | if (m->load) |
| 149 | m->load--; |
| 150 | if (!m->load && hash_extend(&m->t)) |
| 151 | m->load = AM_LOAD(m->t.mask + 1); |
| 152 | return (i); |
| 153 | } |
| 154 | |
| 155 | /* --- @am_remove@ --- * |
| 156 | * |
| 157 | * Arguments: @addrmap *m@ = pointer to map |
| 158 | * @void *i@ = pointer to the item |
| 159 | * |
| 160 | * Returns: --- |
| 161 | * |
| 162 | * Use: Removes an item from the map. |
| 163 | */ |
| 164 | |
| 165 | void am_remove(addrmap *m, void *i) |
| 166 | { |
| 167 | hash_remove(&m->t, i); |
| 168 | x_free(m->t.a, i); |
| 169 | } |
| 170 | |
| 171 | /*----- That's all, folks -------------------------------------------------*/ |