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
  35 struct source *srcs = NULL;
  36
  37 struct source*
  38 find_source(const unsigned char *id, const unsigned char *p, unsigned char plen,
  39             int create, unsigned short seqno)
  40 {
  41     struct source *src;
  42
  43     for(src = srcs; src; src = src->next) {
  44         /* This should really be a hash table.  For now, check the
  45            last byte first. */
  46         if(src->id[7] != id[7])
  47             continue;
  48         if(memcmp(src->id, id, 8) != 0)
  49             continue;
  50         if(src->plen != plen)
  51             continue;
  52         if(memcmp(src->prefix, p, 16) == 0)
  53             return src;
  54     }
  55
  56     if(!create)
  57         return NULL;
  58
  59     src = malloc(sizeof(struct source));
  60     if(src == NULL) {
  61         zlog_err("malloc(source): %s", safe_strerror(errno));
  62         return NULL;
  63     }
  64
  65     memcpy(src->id, id, 8);
  66     memcpy(src->prefix, p, 16);
  67     src->plen = plen;
  68     src->seqno = seqno;
  69     src->metric = INFINITY;
  70     src->time = babel_now.tv_sec;
  71     src->route_count = 0;
  72     src->next = srcs;
  73     srcs = src;
  74     return src;
  75 }
  76
  77 struct source *
  78 retain_source(struct source *src)
  79 {
  80     assert(src->route_count < 0xffff);
  81     src->route_count++;
  82     return src;
  83 }
  84
  85 void
  86 release_source(struct source *src)
  87 {
  88     assert(src->route_count > 0);
  89     src->route_count--;
  90 }
  91
  92 int
  93 flush_source(struct source *src)
  94 {
  95     if(src->route_count > 0)
  96         /* The source is in use by a route. */
  97         return 0;
  98
  99     if(srcs == src) {
 100         srcs = src->next;
 101     } else {
 102         struct source *previous = srcs;
 103         while(previous->next != src)
 104             previous = previous->next;
 105         previous->next = src->next;
 106     }
 107
 108     free(src);
 109     return 1;
 110 }
 111
 112 void
 113 update_source(struct source *src,
 114               unsigned short seqno, unsigned short metric)
 115 {
 116     if(metric >= INFINITY)
 117         return;
 118
 119     /* If a source is expired, pretend that it doesn't exist and update
 120        it unconditionally.  This makes ensures that old data will
 121        eventually be overridden, and prevents us from getting stuck if
 122        a router loses its sequence number. */
 123     if(src->time < babel_now.tv_sec - SOURCE_GC_TIME ||
 124        seqno_compare(src->seqno, seqno) < 0 ||
 125        (src->seqno == seqno && src->metric > metric)) {
 126         src->seqno = seqno;
 127         src->metric = metric;
 128     }
 129     src->time = babel_now.tv_sec;
 130 }
 131
 132 void
 133 expire_sources()
 134 {
 135     struct source *src;
 136
 137     src = srcs;
 138     while(src) {
 139         if(src->time > babel_now.tv_sec)
 140             /* clock stepped */
 141             src->time = babel_now.tv_sec;
 142         if(src->time < babel_now.tv_sec - SOURCE_GC_TIME) {
 143             struct source *old = src;
 144             src = src->next;
 145             flush_source(old);
 146             continue;
 147         }
 148         src = src->next;
 149     }
 150 }
 151
 152 void
 153 check_sources_released(void)
 154 {
 155     struct source *src;
 156
 157     for(src = srcs; src; src = src->next) {
 158         if(src->route_count != 0)
 159             fprintf(stderr, "Warning: source %s %s has refcount %d.\n",
 160                     format_eui64(src->id),
 161                     format_prefix(src->prefix, src->plen),
 162                     (int)src->route_count);
 163     }
 164 }