Author: glebius
Date: Sat Mar 28 16:06:46 2015
New Revision: 280787
URL: https://svnweb.freebsd.org/changeset/base/280787
Log:
Initialize random IP ID engine via SYSINIT() instead of doing that on
first packet. This allow to use M_WAITOK and cut down some error handling.
Sponsored by: Nginx, Inc.
Modified:
head/sys/netinet/ip_id.c
Modified: head/sys/netinet/ip_id.c
==============================================================================
--- head/sys/netinet/ip_id.c Sat Mar 28 15:07:19 2015 (r280786)
+++ head/sys/netinet/ip_id.c Sat Mar 28 16:06:46 2015 (r280787)
@@ -91,18 +91,17 @@ __FBSDID("$FreeBSD$");
static MALLOC_DEFINE(M_IPID, "ipid", "randomized ip id state");
-static u_int16_t *id_array = NULL;
-static bitstr_t *id_bits = NULL;
-static int array_ptr = 0;
-static int array_size = 8192;
-static int random_id_collisions = 0;
-static int random_id_total = 0;
+static uint16_t *id_array;
+static bitstr_t *id_bits;
+static int array_ptr;
+static int array_size;
+static int random_id_collisions;
+static int random_id_total;
static struct mtx ip_id_mtx;
-static void ip_initid(void);
+static void ip_initid(int);
static int sysctl_ip_id_change(SYSCTL_HANDLER_ARGS);
-
-MTX_SYSINIT(ip_id_mtx, &ip_id_mtx, "ip_id_mtx", MTX_DEF);
+static void ip_sysinitid(void);
SYSCTL_DECL(_net_inet_ip);
SYSCTL_PROC(_net_inet_ip, OID_AUTO, random_id_period, CTLTYPE_INT|CTLFLAG_RW,
@@ -120,73 +119,44 @@ sysctl_ip_id_change(SYSCTL_HANDLER_ARGS)
new = array_size;
error = sysctl_handle_int(oidp, &new, 0, req);
if (error == 0 && req->newptr) {
- if (new >= 512 && new <= 32768) {
- mtx_lock(&ip_id_mtx);
- array_size = new;
- ip_initid();
- mtx_unlock(&ip_id_mtx);
- } else
+ if (new >= 512 && new <= 32768)
+ ip_initid(new);
+ else
error = EINVAL;
}
return (error);
}
-/*
- * ip_initid() runs with a mutex held and may execute in a network context.
- * As a result, it uses M_NOWAIT. Ideally, we would always do this
- * allocation from the sysctl contact and have it be an invariant that if
- * this random ID allocation mode is selected, the buffers are present. This
- * would also avoid potential network context failures of IP ID generation.
- */
static void
-ip_initid(void)
+ip_initid(int new_size)
{
+ uint16_t *new_array;
+ bitstr_t *new_bits;
- mtx_assert(&ip_id_mtx, MA_OWNED);
+ new_array = malloc(new_size * sizeof(uint16_t), M_IPID,
+ M_WAITOK | M_ZERO);
+ new_bits = malloc(bitstr_size(65536), M_IPID, M_WAITOK | M_ZERO);
+ mtx_lock(&ip_id_mtx);
if (id_array != NULL) {
free(id_array, M_IPID);
free(id_bits, M_IPID);
}
+ id_array = new_array;
+ id_bits = new_bits;
+ array_size = new_size;
+ array_ptr = 0;
random_id_collisions = 0;
random_id_total = 0;
- array_ptr = 0;
- id_array = (u_int16_t *) malloc(array_size * sizeof(u_int16_t),
- M_IPID, M_NOWAIT | M_ZERO);
- id_bits = (bitstr_t *) malloc(bitstr_size(65536), M_IPID,
- M_NOWAIT | M_ZERO);
- if (id_array == NULL || id_bits == NULL) {
- /* Neither or both. */
- if (id_array != NULL) {
- free(id_array, M_IPID);
- id_array = NULL;
- }
- if (id_bits != NULL) {
- free(id_bits, M_IPID);
- id_bits = NULL;
- }
- }
+ mtx_unlock(&ip_id_mtx);
}
-u_int16_t
+uint16_t
ip_randomid(void)
{
- u_int16_t new_id;
+ uint16_t new_id;
mtx_lock(&ip_id_mtx);
- if (id_array == NULL)
- ip_initid();
-
- /*
- * Fail gracefully; return a fixed id if memory allocation failed;
- * ideally we wouldn't do allocation in this context in order to
- * avoid the possibility of this failure mode.
- */
- if (id_array == NULL) {
- mtx_unlock(&ip_id_mtx);
- return (1);
- }
-
/*
* To avoid a conflict with the zeros that the array is initially
* filled with, we never hand out an id of zero.
@@ -207,3 +177,12 @@ ip_randomid(void)
mtx_unlock(&ip_id_mtx);
return (new_id);
}
+
+static void
+ip_sysinitid(void)
+{
+
+ mtx_init(&ip_id_mtx, "ip_id_mtx", NULL, MTX_DEF);
+ ip_initid(8192);
+}
+SYSINIT(ip_id, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, ip_sysinitid, NULL);
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