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ipc: cache windows lookups to avoid O(n^2) with nested lookups

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Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
This commit is contained in:
Jason A. Donenfeld 2021-06-24 13:35:48 +02:00
parent f65c82456d
commit d58df7ed10
3 changed files with 136 additions and 4 deletions
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20
src/ipc-uapi-windows.h
View File

@ -10,6 +10,7 @@
#include <stdio.h>
#include <stdbool.h>
#include <fcntl.h>
#include <hashtable.h>
static FILE *userspace_interface_file(const char *iface)
{
@ -113,6 +114,9 @@ err:
return NULL;
}
static bool have_cached_interfaces;
static struct hashtable cached_interfaces;
static bool userspace_has_wireguard_interface(const char *iface)
{
char fname[MAX_PATH];
@ -120,10 +124,13 @@ static bool userspace_has_wireguard_interface(const char *iface)
HANDLE find_handle;
bool ret = false;
if (have_cached_interfaces)
return hashtable_find_entry(&cached_interfaces, iface) != NULL;
snprintf(fname, sizeof(fname), "ProtectedPrefix\\Administrators\\WireGuard\\%s", iface);
find_handle = FindFirstFile("\\\\.\\pipe\\*", &find_data);
if (find_handle == INVALID_HANDLE_VALUE)
return -GetLastError();
return -EIO;
do {
if (!strcmp(fname, find_data.cFileName)) {
ret = true;
@ -139,18 +146,25 @@ static int userspace_get_wireguard_interfaces(struct string_list *list)
static const char prefix[] = "ProtectedPrefix\\Administrators\\WireGuard\\";
WIN32_FIND_DATA find_data;
HANDLE find_handle;
char *iface;
int ret = 0;
find_handle = FindFirstFile("\\\\.\\pipe\\*", &find_data);
if (find_handle == INVALID_HANDLE_VALUE)
return -GetLastError();
return -EIO;
do {
if (strncmp(prefix, find_data.cFileName, strlen(prefix)))
continue;
ret = string_list_add(list, find_data.cFileName + strlen(prefix));
iface = find_data.cFileName + strlen(prefix);
ret = string_list_add(list, iface);
if (ret < 0)
goto out;
if (!hashtable_find_or_insert_entry(&cached_interfaces, iface)) {
ret = -errno;
goto out;
}
} while (FindNextFile(find_handle, &find_data));
have_cached_interfaces = true;
out:
FindClose(find_handle);

59
src/ipc-windows.h
View File

@ -13,12 +13,17 @@
#include <ddk/ndisguid.h>
#include <nci.h>
#include <wireguard.h>
#include <hashtable.h>
#define IPC_SUPPORTS_KERNEL_INTERFACE
static bool have_cached_kernel_interfaces;
static struct hashtable cached_kernel_interfaces;
static int kernel_get_wireguard_interfaces(struct string_list *list)
{
HDEVINFO dev_info = SetupDiGetClassDevsExW(&GUID_DEVCLASS_NET, NULL, NULL, DIGCF_PRESENT, NULL, NULL, NULL);
bool will_have_cached_kernel_interfaces = true;
if (dev_info == INVALID_HANDLE_VALUE) {
errno = EACCES;
@ -33,6 +38,7 @@ static int kernel_get_wireguard_interfaces(struct string_list *list)
HKEY key;
GUID instance_id;
char *interface_name;
struct hashtable_entry *entry;
if (!SetupDiEnumDeviceInfo(dev_info, i, &dev_info_data)) {
if (GetLastError() == ERROR_NO_MORE_ITEMS)
@ -105,7 +111,25 @@ static int kernel_get_wireguard_interfaces(struct string_list *list)
}
string_list_add(list, interface_name);
entry = hashtable_find_or_insert_entry(&cached_kernel_interfaces, interface_name);
free(interface_name);
if (!entry)
goto cleanup_entry;
if (SetupDiGetDeviceInstanceIdW(dev_info, &dev_info_data, NULL, 0, &buf_len) || GetLastError() != ERROR_INSUFFICIENT_BUFFER)
goto cleanup_entry;
entry->value = calloc(sizeof(WCHAR), buf_len);
if (!entry->value)
goto cleanup_entry;
if (!SetupDiGetDeviceInstanceIdW(dev_info, &dev_info_data, entry->value, buf_len, &buf_len)) {
free(entry->value);
entry->value = NULL;
goto cleanup_entry;
}
cleanup_entry:
will_have_cached_kernel_interfaces |= entry != NULL && entry->value != NULL;
cleanup_buf:
free(buf);
cleanup_key:
@ -113,15 +137,48 @@ cleanup_key:
skip:;
}
SetupDiDestroyDeviceInfoList(dev_info);
have_cached_kernel_interfaces = will_have_cached_kernel_interfaces;
return 0;
}
static HANDLE kernel_interface_handle(const char *iface)
{
HDEVINFO dev_info = SetupDiGetClassDevsExW(&GUID_DEVCLASS_NET, NULL, NULL, DIGCF_PRESENT, NULL, NULL, NULL);
HDEVINFO dev_info;
WCHAR *interfaces = NULL;
HANDLE handle;
if (have_cached_kernel_interfaces) {
struct hashtable_entry *entry = hashtable_find_entry(&cached_kernel_interfaces, iface);
if (entry) {
DWORD buf_len;
if (CM_Get_Device_Interface_List_SizeW(
&buf_len, (GUID *)&GUID_DEVINTERFACE_NET, (DEVINSTID_W)entry->value,
CM_GET_DEVICE_INTERFACE_LIST_PRESENT) != CR_SUCCESS)
goto err_hash;
interfaces = calloc(buf_len, sizeof(*interfaces));
if (!interfaces)
goto err_hash;
if (CM_Get_Device_Interface_ListW(
(GUID *)&GUID_DEVINTERFACE_NET, (DEVINSTID_W)entry->value, interfaces, buf_len,
CM_GET_DEVICE_INTERFACE_LIST_PRESENT) != CR_SUCCESS || !interfaces[0]) {
free(interfaces);
interfaces = NULL;
goto err_hash;
}
handle = CreateFileW(interfaces, GENERIC_READ | GENERIC_WRITE,
FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE, NULL,
OPEN_EXISTING, 0, NULL);
free(interfaces);
if (handle == INVALID_HANDLE_VALUE)
goto err_hash;
return handle;
err_hash:
errno = EACCES;
return NULL;
}
}
dev_info = SetupDiGetClassDevsExW(&GUID_DEVCLASS_NET, NULL, NULL, DIGCF_PRESENT, NULL, NULL, NULL);
if (dev_info == INVALID_HANDLE_VALUE)
return NULL;

61
src/wincompat/include/hashtable.h Normal file
View File

@ -0,0 +1,61 @@
/* SPDX-License-Identifier: GPL-2.0
*
* Copyright (C) 2018-2021 WireGuard LLC. All Rights Reserved.
*/
#ifndef _HASHTABLE_H
#define _HASHTABLE_H
#include <string.h>
enum { HASHTABLE_ENTRY_BUCKETS_POW2 = 1 << 10 };
struct hashtable_entry {
char *key;
void *value;
struct hashtable_entry *next;
};
struct hashtable {
struct hashtable_entry *entry_buckets[HASHTABLE_ENTRY_BUCKETS_POW2];
};
static unsigned int hashtable_bucket(const char *str)
{
unsigned long hash = 5381;
char c;
while ((c = *str++))
hash = ((hash << 5) + hash) ^ c;
return hash & (HASHTABLE_ENTRY_BUCKETS_POW2 - 1);
}
static struct hashtable_entry *hashtable_find_entry(struct hashtable *hashtable, const char *key)
{
struct hashtable_entry *entry;
for (entry = hashtable->entry_buckets[hashtable_bucket(key)]; entry; entry = entry->next) {
if (!strcmp(entry->key, key))
return entry;
}
return NULL;
}
static struct hashtable_entry *hashtable_find_or_insert_entry(struct hashtable *hashtable, const char *key)
{
struct hashtable_entry **entry;
for (entry = &hashtable->entry_buckets[hashtable_bucket(key)]; *entry; entry = &(*entry)->next) {
if (!strcmp((*entry)->key, key))
return *entry;
}
*entry = calloc(1, sizeof(**entry));
if (!*entry)
return NULL;
(*entry)->key = strdup(key);
if (!(*entry)->key) {
free(*entry);
*entry = NULL;
return NULL;
}
return *entry;
}
#endif