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VNETalize random IP ID engine.

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Sponsored by:	Nginx, Inc.
This commit is contained in:
Gleb Smirnoff 2015-03-28 16:59:57 +00:00
parent 1f08c9479f
commit 513635bfaa
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=280788
1 changed files with 64 additions and 41 deletions
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105
sys/netinet/ip_id.c
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@ -85,38 +85,51 @@ __FBSDID("$FreeBSD$");
#include <sys/random.h>
#include <sys/systm.h>
#include <sys/sysctl.h>
#include <sys/bitstring.h>
#include <net/vnet.h>
#include <netinet/in.h>
#include <netinet/ip_var.h>
#include <sys/bitstring.h>
static MALLOC_DEFINE(M_IPID, "ipid", "randomized ip id state");
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 VNET_DEFINE(uint16_t *, id_array);
static VNET_DEFINE(bitstr_t *, id_bits);
static VNET_DEFINE(int, array_ptr);
static VNET_DEFINE(int, array_size);
static VNET_DEFINE(int, random_id_collisions);
static VNET_DEFINE(int, random_id_total);
static VNET_DEFINE(struct mtx, ip_id_mtx);
#define V_id_array VNET(id_array)
#define V_id_bits VNET(id_bits)
#define V_array_ptr VNET(array_ptr)
#define V_array_size VNET(array_size)
#define V_random_id_collisions VNET(random_id_collisions)
#define V_random_id_total VNET(random_id_total)
#define V_ip_id_mtx VNET(ip_id_mtx)
static void ip_initid(int);
static int sysctl_ip_id_change(SYSCTL_HANDLER_ARGS);
static void ip_sysinitid(void);
static void ipid_sysinit(void);
static void ipid_sysuninit(void);
SYSCTL_DECL(_net_inet_ip);
SYSCTL_PROC(_net_inet_ip, OID_AUTO, random_id_period, CTLTYPE_INT|CTLFLAG_RW,
&array_size, 0, sysctl_ip_id_change, "IU", "IP ID Array size");
SYSCTL_INT(_net_inet_ip, OID_AUTO, random_id_collisions, CTLFLAG_RD,
&random_id_collisions, 0, "Count of IP ID collisions");
SYSCTL_INT(_net_inet_ip, OID_AUTO, random_id_total, CTLFLAG_RD,
&random_id_total, 0, "Count of IP IDs created");
SYSCTL_PROC(_net_inet_ip, OID_AUTO, random_id_period,
CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_VNET,
&VNET_NAME(array_size), 0, sysctl_ip_id_change, "IU", "IP ID Array size");
SYSCTL_INT(_net_inet_ip, OID_AUTO, random_id_collisions,
CTLFLAG_RD | CTLFLAG_VNET,
&VNET_NAME(random_id_collisions), 0, "Count of IP ID collisions");
SYSCTL_INT(_net_inet_ip, OID_AUTO, random_id_total, CTLFLAG_RD | CTLFLAG_VNET,
&VNET_NAME(random_id_total), 0, "Count of IP IDs created");
static int
sysctl_ip_id_change(SYSCTL_HANDLER_ARGS)
{
int error, new;
new = array_size;
new = V_array_size;
error = sysctl_handle_int(oidp, &new, 0, req);
if (error == 0 && req->newptr) {
if (new >= 512 && new <= 32768)
@ -137,18 +150,18 @@ ip_initid(int new_size)
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);
mtx_lock(&V_ip_id_mtx);
if (V_id_array != NULL) {
free(V_id_array, M_IPID);
free(V_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;
mtx_unlock(&ip_id_mtx);
V_id_array = new_array;
V_id_bits = new_bits;
V_array_size = new_size;
V_array_ptr = 0;
V_random_id_collisions = 0;
V_random_id_total = 0;
mtx_unlock(&V_ip_id_mtx);
}
uint16_t
@ -156,7 +169,7 @@ ip_randomid(void)
{
uint16_t new_id;
mtx_lock(&ip_id_mtx);
mtx_lock(&V_ip_id_mtx);
/*
* To avoid a conflict with the zeros that the array is initially
* filled with, we never hand out an id of zero.
@ -164,25 +177,35 @@ ip_randomid(void)
new_id = 0;
do {
if (new_id != 0)
random_id_collisions++;
V_random_id_collisions++;
arc4rand(&new_id, sizeof(new_id), 0);
} while (bit_test(id_bits, new_id) || new_id == 0);
bit_clear(id_bits, id_array[array_ptr]);
bit_set(id_bits, new_id);
id_array[array_ptr] = new_id;
array_ptr++;
if (array_ptr == array_size)
array_ptr = 0;
random_id_total++;
mtx_unlock(&ip_id_mtx);
} while (bit_test(V_id_bits, new_id) || new_id == 0);
bit_clear(V_id_bits, V_id_array[V_array_ptr]);
bit_set(V_id_bits, new_id);
V_id_array[V_array_ptr] = new_id;
V_array_ptr++;
if (V_array_ptr == V_array_size)
V_array_ptr = 0;
V_random_id_total++;
mtx_unlock(&V_ip_id_mtx);
return (new_id);
}
static void
ip_sysinitid(void)
ipid_sysinit(void)
{
mtx_init(&ip_id_mtx, "ip_id_mtx", NULL, MTX_DEF);
mtx_init(&V_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);
VNET_SYSINIT(ip_id, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, ipid_sysinit, NULL);
static void
ipid_sysuninit(void)
{
mtx_destroy(&V_ip_id_mtx);
free(V_id_array, M_IPID);
free(V_id_bits, M_IPID);
}
VNET_SYSUNINIT(ip_id, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, ipid_sysuninit, NULL);