babeld/source.c

   1 /*
   2 Copyright (c) 2007, 2008 by Juliusz Chroboczek
   3
   4 Permission is hereby granted, free of charge, to any person obtaining a copy
   5 of this software and associated documentation files (the "Software"), to deal
   6 in the Software without restriction, including without limitation the rights
   7 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   8 copies of the Software, and to permit persons to whom the Software is
   9 furnished to do so, subject to the following conditions:
  10
  11 The above copyright notice and this permission notice shall be included in
  12 all copies or substantial portions of the Software.
  13
  14 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  15 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  16 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
  17 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  18 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  19 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  20 THE SOFTWARE.
  21 */
  22
  23 #include <stdlib.h>
  24 #include <stdio.h>
  25 #include <string.h>
  26 #include <sys/time.h>
  27
  28 #include "babel_main.h"
  29 #include "babeld.h"
  30 #include "util.h"
  31 #include "source.h"
  32 #include "babel_interface.h"
  33 #include "route.h"
  34 #include "babel_errors.h"
  35
  36 struct source *srcs = NULL;
  37
  38 struct source*
  39 find_source(const unsigned char *id, const unsigned char *p, unsigned char plen,
  40             int create, unsigned short seqno)
  41 {
  42     struct source *src;
  43
  44     for(src = srcs; src; src = src->next) {
  45         /* This should really be a hash table.  For now, check the
  46            last byte first. */
  47         if(src->id[7] != id[7])
  48             continue;
  49         if(memcmp(src->id, id, 8) != 0)
  50             continue;
  51         if(src->plen != plen)
  52             continue;
  53         if(memcmp(src->prefix, p, 16) == 0)
  54             return src;
  55     }
  56
  57     if(!create)
  58         return NULL;
  59
  60     src = malloc(sizeof(struct source));
  61     if(src == NULL) {
  62         flog_err(BABEL_ERR_MEMORY, "malloc(source): %s", safe_strerror(errno));
  63         return NULL;
  64     }
  65
  66     memcpy(src->id, id, 8);
  67     memcpy(src->prefix, p, 16);
  68     src->plen = plen;
  69     src->seqno = seqno;
  70     src->metric = INFINITY;
  71     src->time = babel_now.tv_sec;
  72     src->route_count = 0;
  73     src->next = srcs;
  74     srcs = src;
  75     return src;
  76 }
  77
  78 struct source *
  79 retain_source(struct source *src)
  80 {
  81     assert(src->route_count < 0xffff);
  82     src->route_count++;
  83     return src;
  84 }
  85
  86 void
  87 release_source(struct source *src)
  88 {
  89     assert(src->route_count > 0);
  90     src->route_count--;
  91 }
  92
  93 int
  94 flush_source(struct source *src)
  95 {
  96     if(src->route_count > 0)
  97         /* The source is in use by a route. */
  98         return 0;
  99
 100     if(srcs == src) {
 101         srcs = src->next;
 102     } else {
 103         struct source *previous = srcs;
 104         while(previous->next != src)
 105             previous = previous->next;
 106         previous->next = src->next;
 107     }
 108
 109     free(src);
 110     return 1;
 111 }
 112
 113 void
 114 update_source(struct source *src,
 115               unsigned short seqno, unsigned short metric)
 116 {
 117     if(metric >= INFINITY)
 118         return;
 119
 120     /* If a source is expired, pretend that it doesn't exist and update
 121        it unconditionally.  This makes ensures that old data will
 122        eventually be overridden, and prevents us from getting stuck if
 123        a router loses its sequence number. */
 124     if(src->time < babel_now.tv_sec - SOURCE_GC_TIME ||
 125        seqno_compare(src->seqno, seqno) < 0 ||
 126        (src->seqno == seqno && src->metric > metric)) {
 127         src->seqno = seqno;
 128         src->metric = metric;
 129     }
 130     src->time = babel_now.tv_sec;
 131 }
 132
 133 void
 134 expire_sources()
 135 {
 136     struct source *src;
 137
 138     src = srcs;
 139     while(src) {
 140         if(src->time > babel_now.tv_sec)
 141             /* clock stepped */
 142             src->time = babel_now.tv_sec;
 143         if(src->time < babel_now.tv_sec - SOURCE_GC_TIME) {
 144             struct source *old = src;
 145             src = src->next;
 146             flush_source(old);
 147             continue;
 148         }
 149         src = src->next;
 150     }
 151 }
 152
 153 void
 154 check_sources_released(void)
 155 {
 156     struct source *src;
 157
 158     for(src = srcs; src; src = src->next) {
 159         if(src->route_count != 0)
 160             fprintf(stderr, "Warning: source %s %s has refcount %d.\n",
 161                     format_eui64(src->id),
 162                     format_prefix(src->prefix, src->plen),
 163                     (int)src->route_count);
 164     }
 165 }