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 #ifdef HAVE_CONFIG_H
  24 #include "config.h"
  25 #endif
  26
  27 #include <stdlib.h>
  28 #include <stdio.h>
  29 #include <string.h>
  30 #include <sys/time.h>
  31
  32 #include "babel_main.h"
  33 #include "babeld.h"
  34 #include "util.h"
  35 #include "source.h"
  36 #include "babel_interface.h"
  37 #include "route.h"
  38 #include "babel_errors.h"
  39
  40 struct source *srcs = NULL;
  41
  42 struct source*
  43 find_source(const unsigned char *id, const unsigned char *p, unsigned char plen,
  44             int create, unsigned short seqno)
  45 {
  46     struct source *src;
  47
  48     for(src = srcs; src; src = src->next) {
  49         /* This should really be a hash table.  For now, check the
  50            last byte first. */
  51         if(src->id[7] != id[7])
  52             continue;
  53         if(memcmp(src->id, id, 8) != 0)
  54             continue;
  55         if(src->plen != plen)
  56             continue;
  57         if(memcmp(src->prefix, p, 16) == 0)
  58             return src;
  59     }
  60
  61     if(!create)
  62         return NULL;
  63
  64     src = malloc(sizeof(struct source));
  65     if(src == NULL) {
  66         flog_err(EC_BABEL_MEMORY, "malloc(source): %s", safe_strerror(errno));
  67         return NULL;
  68     }
  69
  70     memcpy(src->id, id, 8);
  71     memcpy(src->prefix, p, 16);
  72     src->plen = plen;
  73     src->seqno = seqno;
  74     src->metric = INFINITY;
  75     src->time = babel_now.tv_sec;
  76     src->route_count = 0;
  77     src->next = srcs;
  78     srcs = src;
  79     return src;
  80 }
  81
  82 struct source *
  83 retain_source(struct source *src)
  84 {
  85     assert(src->route_count < 0xffff);
  86     src->route_count++;
  87     return src;
  88 }
  89
  90 void
  91 release_source(struct source *src)
  92 {
  93     assert(src->route_count > 0);
  94     src->route_count--;
  95 }
  96
  97 int
  98 flush_source(struct source *src)
  99 {
 100     if(src->route_count > 0)
 101         /* The source is in use by a route. */
 102         return 0;
 103
 104     if(srcs == src) {
 105         srcs = src->next;
 106     } else {
 107         struct source *previous = srcs;
 108         while(previous->next != src)
 109             previous = previous->next;
 110         previous->next = src->next;
 111     }
 112
 113     free(src);
 114     return 1;
 115 }
 116
 117 void
 118 update_source(struct source *src,
 119               unsigned short seqno, unsigned short metric)
 120 {
 121     if(metric >= INFINITY)
 122         return;
 123
 124     /* If a source is expired, pretend that it doesn't exist and update
 125        it unconditionally.  This makes ensures that old data will
 126        eventually be overridden, and prevents us from getting stuck if
 127        a router loses its sequence number. */
 128     if(src->time < babel_now.tv_sec - SOURCE_GC_TIME ||
 129        seqno_compare(src->seqno, seqno) < 0 ||
 130        (src->seqno == seqno && src->metric > metric)) {
 131         src->seqno = seqno;
 132         src->metric = metric;
 133     }
 134     src->time = babel_now.tv_sec;
 135 }
 136
 137 void
 138 expire_sources(void)
 139 {
 140     struct source *src;
 141
 142     src = srcs;
 143     while(src) {
 144         if(src->time > babel_now.tv_sec)
 145             /* clock stepped */
 146             src->time = babel_now.tv_sec;
 147         if(src->time < babel_now.tv_sec - SOURCE_GC_TIME) {
 148             struct source *old = src;
 149             src = src->next;
 150             flush_source(old);
 151             continue;
 152         }
 153         src = src->next;
 154     }
 155 }
 156
 157 void
 158 check_sources_released(void)
 159 {
 160     struct source *src;
 161
 162     for(src = srcs; src; src = src->next) {
 163         if(src->route_count != 0)
 164             fprintf(stderr, "Warning: source %s %s has refcount %d.\n",
 165                     format_eui64(src->id),
 166                     format_prefix(src->prefix, src->plen),
 167                     (int)src->route_count);
 168     }
 169 }