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.
This commit is contained in:
parent
a04d412295
commit
1f08c9479f
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=280787
@ -91,18 +91,17 @@ __FBSDID("$FreeBSD$");
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static MALLOC_DEFINE(M_IPID, "ipid", "randomized ip id state");
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static u_int16_t *id_array = NULL;
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static bitstr_t *id_bits = NULL;
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static int array_ptr = 0;
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static int array_size = 8192;
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static int random_id_collisions = 0;
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static int random_id_total = 0;
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static uint16_t *id_array;
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static bitstr_t *id_bits;
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static int array_ptr;
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static int array_size;
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static int random_id_collisions;
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static int random_id_total;
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static struct mtx ip_id_mtx;
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static void ip_initid(void);
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static void ip_initid(int);
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static int sysctl_ip_id_change(SYSCTL_HANDLER_ARGS);
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MTX_SYSINIT(ip_id_mtx, &ip_id_mtx, "ip_id_mtx", MTX_DEF);
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static void ip_sysinitid(void);
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SYSCTL_DECL(_net_inet_ip);
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SYSCTL_PROC(_net_inet_ip, OID_AUTO, random_id_period, CTLTYPE_INT|CTLFLAG_RW,
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@ -120,73 +119,44 @@ sysctl_ip_id_change(SYSCTL_HANDLER_ARGS)
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new = array_size;
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error = sysctl_handle_int(oidp, &new, 0, req);
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if (error == 0 && req->newptr) {
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if (new >= 512 && new <= 32768) {
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mtx_lock(&ip_id_mtx);
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array_size = new;
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ip_initid();
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mtx_unlock(&ip_id_mtx);
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} else
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if (new >= 512 && new <= 32768)
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ip_initid(new);
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else
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error = EINVAL;
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}
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return (error);
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}
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/*
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* ip_initid() runs with a mutex held and may execute in a network context.
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* As a result, it uses M_NOWAIT. Ideally, we would always do this
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* allocation from the sysctl contact and have it be an invariant that if
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* this random ID allocation mode is selected, the buffers are present. This
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* would also avoid potential network context failures of IP ID generation.
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*/
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static void
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ip_initid(void)
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ip_initid(int new_size)
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{
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uint16_t *new_array;
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bitstr_t *new_bits;
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mtx_assert(&ip_id_mtx, MA_OWNED);
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new_array = malloc(new_size * sizeof(uint16_t), M_IPID,
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M_WAITOK | M_ZERO);
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new_bits = malloc(bitstr_size(65536), M_IPID, M_WAITOK | M_ZERO);
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mtx_lock(&ip_id_mtx);
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if (id_array != NULL) {
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free(id_array, M_IPID);
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free(id_bits, M_IPID);
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}
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id_array = new_array;
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id_bits = new_bits;
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array_size = new_size;
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array_ptr = 0;
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random_id_collisions = 0;
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random_id_total = 0;
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array_ptr = 0;
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id_array = (u_int16_t *) malloc(array_size * sizeof(u_int16_t),
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M_IPID, M_NOWAIT | M_ZERO);
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id_bits = (bitstr_t *) malloc(bitstr_size(65536), M_IPID,
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M_NOWAIT | M_ZERO);
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if (id_array == NULL || id_bits == NULL) {
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/* Neither or both. */
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if (id_array != NULL) {
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free(id_array, M_IPID);
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id_array = NULL;
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}
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if (id_bits != NULL) {
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free(id_bits, M_IPID);
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id_bits = NULL;
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}
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}
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mtx_unlock(&ip_id_mtx);
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}
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u_int16_t
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uint16_t
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ip_randomid(void)
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{
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u_int16_t new_id;
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uint16_t new_id;
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mtx_lock(&ip_id_mtx);
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if (id_array == NULL)
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ip_initid();
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/*
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* Fail gracefully; return a fixed id if memory allocation failed;
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* ideally we wouldn't do allocation in this context in order to
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* avoid the possibility of this failure mode.
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*/
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if (id_array == NULL) {
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mtx_unlock(&ip_id_mtx);
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return (1);
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}
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/*
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* To avoid a conflict with the zeros that the array is initially
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* filled with, we never hand out an id of zero.
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@ -207,3 +177,12 @@ ip_randomid(void)
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mtx_unlock(&ip_id_mtx);
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return (new_id);
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}
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static void
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ip_sysinitid(void)
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{
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mtx_init(&ip_id_mtx, "ip_id_mtx", NULL, MTX_DEF);
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ip_initid(8192);
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}
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SYSINIT(ip_id, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, ip_sysinitid, NULL);
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