If not, my proposal:
I set an incomplete (prefix) lxc.network.hwaddr in default conf.
lxc-create complete it randomly and write it to the container's
config.
Does it make sense?
I think so. Just 'xx' in place of real numbers?
I do not/can't code in C, but perhaps I should try ...
Guillaume ZITTA
Please be kind, it's the second time I do "C" of my life :)
Note about randinit():
that kind of util can be used in network.c/lxc_mkifname() and
lxccontainer.c/new_hwaddr()
It works for me, I did 1000 destroy/create (with fake template) in 43
sec without mac duplicate.
If I'm not completely doing wrong, I'll provide patch for manpage and
HAVE_RAND_R ifdef.
please comment.
diff --git a/src/lxc/confile.c b/src/lxc/confile.c
index c5ec4f3..5721e05 100644
--- a/src/lxc/confile.c
+++ b/src/lxc/confile.c
@@ -509,6 +509,24 @@ static int macvlan_mode(int *valuep, const char
*value)
return -1;
}
+char *rand_complete_hwaddr(const char *hwaddr)
+{
+ const char hex[] = "0123456789abcdef";
+ char *retval=NULL;
+ retval = strdup(hwaddr);
+ char *curs = retval;
+
+ randinit();
+
+ while (*curs != '\0')
+ {
+ if ( *curs == 'x' || *curs == 'X' )
+ *curs = hex[rand() & 0x0F];
+ curs++;
+ }
+ return retval;
+}
+
static int config_network_flags(const char *key, const char *value,
struct lxc_conf *lxc_conf)
{
@@ -576,11 +594,13 @@ static int config_network_hwaddr(const char *key,
const char *value,
{
struct lxc_netdev *netdev;
- netdev = network_netdev(key, value, &lxc_conf->network);
+ const char *newval = rand_complete_hwaddr(value);
+
+ netdev = network_netdev(key, newval, &lxc_conf->network);
if (!netdev)
return -1;
- return config_string_item(&netdev->hwaddr, value);
+ return config_string_item(&netdev->hwaddr, newval);
}
static int config_network_vlan_id(const char *key, const char *value,
diff --git a/src/lxc/utils.c b/src/lxc/utils.c
index 785f3e6..204179e 100644
--- a/src/lxc/utils.c
+++ b/src/lxc/utils.c
@@ -1126,3 +1126,25 @@ void **lxc_append_null_to_array(void **array,
size_t count)
}
return array;
}
+
+void randinit(void)
+{
+ /*
+ srand pre-seed function based on /dev/urandom
+ */
+ FILE *f;
+ process_lock();
+ f = fopen("/dev/urandom", "r");
+ process_unlock();
+ if (f) {
+ unsigned int seed;
+ int ret = fread(&seed, sizeof(seed), 1, f);
+ if (ret != 1)
+ seed = time(NULL);
+ process_lock();
+ fclose(f);
+ process_unlock();
+ srand(seed);
+ } else
+ srand(time(NULL));
+}
\ No newline at end of file
diff --git a/src/lxc/utils.h b/src/lxc/utils.h
index 945f1de..f20339b 100644
--- a/src/lxc/utils.h
+++ b/src/lxc/utils.h
@@ -270,4 +270,7 @@ extern void **lxc_dup_array(void **array, lxc_dup_fn
element_dup_fn, lxc_free_fn
extern void **lxc_append_null_to_array(void **array, size_t count);
extern void dump_stacktrace(void);
+
+//initialize rand with urandom
+extern void randinit(void);
#endif
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