babeld/source.c

   1 // SPDX-License-Identifier: MIT
   2 /*
   3 Copyright (c) 2007, 2008 by Juliusz Chroboczek
   4 */
   5
   6 #ifdef HAVE_CONFIG_H
   7 #include "config.h"
   8 #endif
   9
  10 #include <stdlib.h>
  11 #include <stdio.h>
  12 #include <string.h>
  13 #include <sys/time.h>
  14
  15 #include "babel_main.h"
  16 #include "babeld.h"
  17 #include "util.h"
  18 #include "source.h"
  19 #include "babel_interface.h"
  20 #include "route.h"
  21 #include "babel_errors.h"
  22
  23 struct source *srcs = NULL;
  24
  25 struct source*
  26 find_source(const unsigned char *id, const unsigned char *p, unsigned char plen,
  27             int create, unsigned short seqno)
  28 {
  29     struct source *src;
  30
  31     for(src = srcs; src; src = src->next) {
  32         /* This should really be a hash table.  For now, check the
  33            last byte first. */
  34         if(src->id[7] != id[7])
  35             continue;
  36         if(memcmp(src->id, id, 8) != 0)
  37             continue;
  38         if(src->plen != plen)
  39             continue;
  40         if(memcmp(src->prefix, p, 16) == 0)
  41             return src;
  42     }
  43
  44     if(!create)
  45         return NULL;
  46
  47     src = malloc(sizeof(struct source));
  48     if(src == NULL) {
  49         flog_err(EC_BABEL_MEMORY, "malloc(source): %s", safe_strerror(errno));
  50         return NULL;
  51     }
  52
  53     memcpy(src->id, id, 8);
  54     memcpy(src->prefix, p, 16);
  55     src->plen = plen;
  56     src->seqno = seqno;
  57     src->metric = INFINITY;
  58     src->time = babel_now.tv_sec;
  59     src->route_count = 0;
  60     src->next = srcs;
  61     srcs = src;
  62     return src;
  63 }
  64
  65 struct source *
  66 retain_source(struct source *src)
  67 {
  68     assert(src->route_count < 0xffff);
  69     src->route_count++;
  70     return src;
  71 }
  72
  73 void
  74 release_source(struct source *src)
  75 {
  76     assert(src->route_count > 0);
  77     src->route_count--;
  78 }
  79
  80 int
  81 flush_source(struct source *src)
  82 {
  83     if(src->route_count > 0)
  84         /* The source is in use by a route. */
  85         return 0;
  86
  87     if(srcs == src) {
  88         srcs = src->next;
  89     } else {
  90         struct source *previous = srcs;
  91         while(previous->next != src)
  92             previous = previous->next;
  93         previous->next = src->next;
  94     }
  95
  96     free(src);
  97     return 1;
  98 }
  99
 100 void
 101 update_source(struct source *src,
 102               unsigned short seqno, unsigned short metric)
 103 {
 104     if(metric >= INFINITY)
 105         return;
 106
 107     /* If a source is expired, pretend that it doesn't exist and update
 108        it unconditionally.  This makes ensures that old data will
 109        eventually be overridden, and prevents us from getting stuck if
 110        a router loses its sequence number. */
 111     if(src->time < babel_now.tv_sec - SOURCE_GC_TIME ||
 112        seqno_compare(src->seqno, seqno) < 0 ||
 113        (src->seqno == seqno && src->metric > metric)) {
 114         src->seqno = seqno;
 115         src->metric = metric;
 116     }
 117     src->time = babel_now.tv_sec;
 118 }
 119
 120 void
 121 expire_sources(void)
 122 {
 123     struct source *src;
 124
 125     src = srcs;
 126     while(src) {
 127         if(src->time > babel_now.tv_sec)
 128             /* clock stepped */
 129             src->time = babel_now.tv_sec;
 130         if(src->time < babel_now.tv_sec - SOURCE_GC_TIME) {
 131             struct source *old = src;
 132             src = src->next;
 133             flush_source(old);
 134             continue;
 135         }
 136         src = src->next;
 137     }
 138 }
 139
 140 void
 141 check_sources_released(void)
 142 {
 143     struct source *src;
 144
 145     for(src = srcs; src; src = src->next) {
 146         if(src->route_count != 0)
 147             fprintf(stderr, "Warning: source %s %s has refcount %d.\n",
 148                     format_eui64(src->id),
 149                     format_prefix(src->prefix, src->plen),
 150                     (int)src->route_count);
 151     }
 152 }