| 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 |
| 13 | * it under the terms of the GNU General Public License as published by |
| 14 | * the Free Software Foundation; either version 2 of the License, or |
| 15 | * (at your option) any later version. |
| 16 | * |
| 17 | * TrIPE is distributed in the hope that it will be useful, |
| 18 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 20 | * GNU General Public License for more details. |
| 21 | * |
| 22 | * You should have received a copy of the GNU General Public License |
| 23 | * along with TrIPE; if not, write to the Free Software Foundation, |
| 24 | * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
| 25 | */ |
| 26 | |
| 27 | /*----- Header files ------------------------------------------------------*/ |
| 28 | |
| 29 | #include "tripe.h" |
| 30 | |
| 31 | #define AM_LOAD(n) (((n) * 3)/2) |
| 32 | |
| 33 | /*----- Main code ---------------------------------------------------------*/ |
| 34 | |
| 35 | /* --- @am_create@ --- * |
| 36 | * |
| 37 | * Arguments: @addrmap *m@ = pointer to map |
| 38 | * |
| 39 | * Returns: --- |
| 40 | * |
| 41 | * Use: Create an address map, properly set up. |
| 42 | */ |
| 43 | |
| 44 | void am_create(addrmap *m) |
| 45 | { |
| 46 | hash_create(&m->t, 16); |
| 47 | m->load = AM_LOAD(m->t.mask + 1); |
| 48 | } |
| 49 | |
| 50 | /* --- @am_destroy@ --- * |
| 51 | * |
| 52 | * Arguments: @addrmap *m@ = pointer to map |
| 53 | * |
| 54 | * Returns: --- |
| 55 | * |
| 56 | * Use: Destroy an address map, throwing away all the entries. |
| 57 | */ |
| 58 | |
| 59 | void am_destroy(addrmap *m) |
| 60 | { |
| 61 | hash_base *p; |
| 62 | hash_iter i; |
| 63 | |
| 64 | for (hash_mkiter(&i, &m->t); (p = hash_next(&i)) != 0; ) |
| 65 | x_free(m->t.a, p); |
| 66 | hash_destroy(&m->t); |
| 67 | } |
| 68 | |
| 69 | /* --- @hash@ --- * |
| 70 | * |
| 71 | * Arguments: @const addr *a@ = pointer to address |
| 72 | * |
| 73 | * Returns: The hash of the address. |
| 74 | */ |
| 75 | |
| 76 | uint32 hash(const addr *a) |
| 77 | { |
| 78 | switch (a->sa.sa_family) { |
| 79 | case AF_INET: |
| 80 | return (U32((AF_INET * 0x4eaac1b7ul) + |
| 81 | (a->sin.sin_addr.s_addr * 0xa5dbc837) + |
| 82 | (a->sin.sin_port * 0x3b049e83))); |
| 83 | default: |
| 84 | abort(); |
| 85 | } |
| 86 | } |
| 87 | |
| 88 | /* --- @addreq@ --- * |
| 89 | * |
| 90 | * Arguments: @const addr *a, *b@ = pointer to addresses |
| 91 | * |
| 92 | * Returns: Nonzero if the addresses are equal. |
| 93 | */ |
| 94 | |
| 95 | int addreq(const addr *a, const addr *b) |
| 96 | { |
| 97 | if (a->sa.sa_family != b->sa.sa_family) |
| 98 | return (0); |
| 99 | switch (a->sa.sa_family) { |
| 100 | case AF_INET: |
| 101 | return (a->sin.sin_addr.s_addr == b->sin.sin_addr.s_addr && |
| 102 | a->sin.sin_port == b->sin.sin_port); |
| 103 | default: |
| 104 | abort(); |
| 105 | } |
| 106 | } |
| 107 | |
| 108 | /* --- @am_find@ --- * |
| 109 | * |
| 110 | * Arguments: @addrmap *m@ = pointer to map |
| 111 | * @const addr *a@ = address to look up |
| 112 | * @size_t sz@ = size of block to allocate |
| 113 | * @unsigned *f@ = where to store flags |
| 114 | * |
| 115 | * Returns: Pointer to found item, or null. |
| 116 | * |
| 117 | * Use: Finds a record with the given IP address, set @*f@ nonzero |
| 118 | * and returns it. If @sz@ is zero, and no match was found, |
| 119 | * return null; otherwise allocate a new block of @sz@ bytes, |
| 120 | * clear @*f@ to zero and return the block pointer. |
| 121 | */ |
| 122 | |
| 123 | void *am_find(addrmap *m, const addr *a, size_t sz, unsigned *f) |
| 124 | { |
| 125 | uint32 h = hash(a); |
| 126 | hash_base **b, **bb; |
| 127 | addrmap_base *i; |
| 128 | |
| 129 | bb = HASH_BIN(&m->t, h); |
| 130 | for (b = bb; *b; b = &(*b)->next) { |
| 131 | i = (addrmap_base *)*b; |
| 132 | if (i->b.hash == h && addreq(a, &i->a)) { |
| 133 | *b = i->b.next; |
| 134 | i->b.next = *bb; |
| 135 | *bb = &i->b; |
| 136 | if (f) *f = 1; |
| 137 | return (i); |
| 138 | } |
| 139 | } |
| 140 | |
| 141 | if (f) *f = 0; |
| 142 | if (!sz) return (0); |
| 143 | i = x_alloc(m->t.a, sz); |
| 144 | i->b.hash = h; |
| 145 | i->b.next = *bb; |
| 146 | *bb = &i->b; |
| 147 | i->a = *a; |
| 148 | |
| 149 | if (m->load) |
| 150 | m->load--; |
| 151 | if (!m->load && hash_extend(&m->t)) |
| 152 | m->load = AM_LOAD(m->t.mask + 1); |
| 153 | return (i); |
| 154 | } |
| 155 | |
| 156 | /* --- @am_remove@ --- * |
| 157 | * |
| 158 | * Arguments: @addrmap *m@ = pointer to map |
| 159 | * @void *i@ = pointer to the item |
| 160 | * |
| 161 | * Returns: --- |
| 162 | * |
| 163 | * Use: Removes an item from the map. |
| 164 | */ |
| 165 | |
| 166 | void am_remove(addrmap *m, void *i) |
| 167 | { |
| 168 | hash_remove(&m->t, i); |
| 169 | x_free(m->t.a, i); |
| 170 | } |
| 171 | |
| 172 | /*----- That's all, folks -------------------------------------------------*/ |