BadVPN – Rev 1
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/**
* @file net_dns.c
* @author Ambroz Bizjak <ambrop7@gmail.com>
*
* @section LICENSE
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the author nor the
* names of its contributors may be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* @section DESCRIPTION
*
* DNS servers module.
*
* Synopsis: net.dns(list(string) servers, string priority)
* Synopsis: net.dns.resolvconf(list({string type, string value}) lines, string priority)
*/
#include <stdlib.h>
#include <string.h>
#include <limits.h>
#include <misc/offset.h>
#include <misc/bsort.h>
#include <misc/balloc.h>
#include <misc/compare.h>
#include <misc/concat_strings.h>
#include <misc/expstring.h>
#include <misc/ipaddr.h>
#include <structure/LinkedList1.h>
#include <ncd/extra/NCDIfConfig.h>
#include <ncd/module_common.h>
#include <generated/blog_channel_ncd_net_dns.h>
struct instance {
NCDModuleInst *i;
LinkedList1 entries;
LinkedList1Node instances_node; // node in instances
};
struct dns_entry {
LinkedList1Node list_node; // node in instance.entries
char *line;
int priority;
};
struct global {
LinkedList1 instances;
};
static struct dns_entry * add_dns_entry (struct instance *o, const char *type, const char *value, int priority)
{
// allocate entry
struct dns_entry *entry = malloc(sizeof(*entry));
if (!entry) {
goto fail0;
}
// generate line
entry->line = concat_strings(4, type, " ", value, "\n");
if (!entry->line) {
goto fail1;
}
// set info
entry->priority = priority;
// add to list
LinkedList1_Append(&o->entries, &entry->list_node);
return entry;
fail1:
free(entry);
fail0:
return NULL;
}
static void remove_dns_entry (struct instance *o, struct dns_entry *entry)
{
// remove from list
LinkedList1_Remove(&o->entries, &entry->list_node);
// free line
free(entry->line);
// free entry
free(entry);
}
static void remove_entries (struct instance *o)
{
LinkedList1Node *n;
while (n = LinkedList1_GetFirst(&o->entries)) {
struct dns_entry *e = UPPER_OBJECT(n, struct dns_entry, list_node);
remove_dns_entry(o, e);
}
}
static size_t count_entries (struct global *g)
{
size_t c = 0;
for (LinkedList1Node *n = LinkedList1_GetFirst(&g->instances); n; n = LinkedList1Node_Next(n)) {
struct instance *o = UPPER_OBJECT(n, struct instance, instances_node);
for (LinkedList1Node *en = LinkedList1_GetFirst(&o->entries); en; en = LinkedList1Node_Next(en)) {
c++;
}
}
return c;
}
struct dns_sort_entry {
char *line;
int priority;
};
static int dns_sort_comparator (const void *v1, const void *v2)
{
const struct dns_sort_entry *e1 = v1;
const struct dns_sort_entry *e2 = v2;
return B_COMPARE(e1->priority, e2->priority);
}
static int set_servers (struct global *g)
{
int ret = 0;
// count servers
size_t num_entries = count_entries(g);
// allocate sort array
struct dns_sort_entry *sort_entries = BAllocArray(num_entries, sizeof(sort_entries[0]));
if (!sort_entries) {
goto fail0;
}
// fill sort array
num_entries = 0;
for (LinkedList1Node *n = LinkedList1_GetFirst(&g->instances); n; n = LinkedList1Node_Next(n)) {
struct instance *o = UPPER_OBJECT(n, struct instance, instances_node);
for (LinkedList1Node *en = LinkedList1_GetFirst(&o->entries); en; en = LinkedList1Node_Next(en)) {
struct dns_entry *e = UPPER_OBJECT(en, struct dns_entry, list_node);
sort_entries[num_entries].line = e->line;
sort_entries[num_entries].priority= e->priority;
num_entries++;
}
}
// sort by priority
// use a custom insertion sort instead of qsort() because we want a stable sort
struct dns_sort_entry temp;
BInsertionSort(sort_entries, num_entries, sizeof(sort_entries[0]), dns_sort_comparator, &temp);
ExpString estr;
if (!ExpString_Init(&estr)) {
goto fail1;
}
for (size_t i = 0; i < num_entries; i++) {
if (!ExpString_Append(&estr, sort_entries[i].line)) {
goto fail2;
}
}
// set servers
if (!NCDIfConfig_set_resolv_conf(ExpString_Get(&estr), ExpString_Length(&estr))) {
goto fail2;
}
ret = 1;
fail2:
ExpString_Free(&estr);
fail1:
BFree(sort_entries);
fail0:
return ret;
}
static int func_globalinit (struct NCDInterpModuleGroup *group, const struct NCDModuleInst_iparams *params)
{
// allocate global state structure
struct global *g = BAlloc(sizeof(*g));
if (!g) {
BLog(BLOG_ERROR, "BAlloc failed");
return 0;
}
// set group state pointer
group->group_state = g;
// init instances list
LinkedList1_Init(&g->instances);
return 1;
}
static void func_globalfree (struct NCDInterpModuleGroup *group)
{
struct global *g = group->group_state;
ASSERT(LinkedList1_IsEmpty(&g->instances))
// free global state structure
BFree(g);
}
static void func_new (void *vo, NCDModuleInst *i, const struct NCDModuleInst_new_params *params)
{
struct global *g = ModuleGlobal(i);
struct instance *o = vo;
o->i = i;
// init servers list
LinkedList1_Init(&o->entries);
// get arguments
NCDValRef servers_arg;
NCDValRef priority_arg;
if (!NCDVal_ListRead(params->args, 2, &servers_arg, &priority_arg)) {
ModuleLog(o->i, BLOG_ERROR, "wrong arity");
goto fail1;
}
if (!NCDVal_IsList(servers_arg)) {
ModuleLog(o->i, BLOG_ERROR, "wrong type");
goto fail1;
}
uintmax_t priority;
if (!ncd_read_uintmax(priority_arg, &priority) || priority > INT_MAX) {
ModuleLog(o->i, BLOG_ERROR, "wrong priority");
goto fail1;
}
// read servers
size_t count = NCDVal_ListCount(servers_arg);
for (size_t j = 0; j < count; j++) {
NCDValRef server_arg = NCDVal_ListGet(servers_arg, j);
if (!NCDVal_IsString(server_arg)) {
ModuleLog(o->i, BLOG_ERROR, "wrong type");
goto fail1;
}
uint32_t addr;
if (!ipaddr_parse_ipv4_addr(NCDVal_StringMemRef(server_arg), &addr)) {
ModuleLog(o->i, BLOG_ERROR, "wrong addr");
goto fail1;
}
char addr_str[IPADDR_PRINT_MAX];
ipaddr_print_addr(addr, addr_str);
if (!add_dns_entry(o, "nameserver", addr_str, priority)) {
ModuleLog(o->i, BLOG_ERROR, "failed to add dns entry");
goto fail1;
}
}
// add to instances
LinkedList1_Append(&g->instances, &o->instances_node);
// set servers
if (!set_servers(g)) {
ModuleLog(o->i, BLOG_ERROR, "failed to set DNS servers");
goto fail2;
}
// signal up
NCDModuleInst_Backend_Up(o->i);
return;
fail2:
LinkedList1_Remove(&g->instances, &o->instances_node);
fail1:
remove_entries(o);
NCDModuleInst_Backend_DeadError(i);
}
static void func_new_resolvconf (void *vo, NCDModuleInst *i, const struct NCDModuleInst_new_params *params)
{
struct global *g = ModuleGlobal(i);
struct instance *o = vo;
o->i = i;
// init servers list
LinkedList1_Init(&o->entries);
// get arguments
NCDValRef lines_arg;
NCDValRef priority_arg;
if (!NCDVal_ListRead(params->args, 2, &lines_arg, &priority_arg)) {
ModuleLog(o->i, BLOG_ERROR, "wrong arity");
goto fail1;
}
if (!NCDVal_IsList(lines_arg)) {
ModuleLog(o->i, BLOG_ERROR, "wrong type");
goto fail1;
}
uintmax_t priority;
if (!ncd_read_uintmax(priority_arg, &priority) || priority > INT_MAX) {
ModuleLog(o->i, BLOG_ERROR, "wrong priority");
goto fail1;
}
// read lines
size_t count = NCDVal_ListCount(lines_arg);
for (size_t j = 0; j < count; j++) {
int loop_failed = 1;
NCDValRef line = NCDVal_ListGet(lines_arg, j);
if (!NCDVal_IsList(line) || NCDVal_ListCount(line) != 2) {
ModuleLog(o->i, BLOG_ERROR, "lines element is not a list with two elements");
goto loop_fail0;
}
NCDValRef type = NCDVal_ListGet(line, 0);
NCDValRef value = NCDVal_ListGet(line, 1);
if (!NCDVal_IsStringNoNulls(type) || !NCDVal_IsStringNoNulls(value)) {
ModuleLog(o->i, BLOG_ERROR, "wrong type of type or value");
goto loop_fail0;
}
NCDValNullTermString type_nts;
if (!NCDVal_StringNullTerminate(type, &type_nts)) {
ModuleLog(o->i, BLOG_ERROR, "NCDVal_StringNullTerminate failed");
goto loop_fail0;
}
NCDValNullTermString value_nts;
if (!NCDVal_StringNullTerminate(value, &value_nts)) {
ModuleLog(o->i, BLOG_ERROR, "NCDVal_StringNullTerminate failed");
goto loop_fail1;
}
if (!add_dns_entry(o, type_nts.data, value_nts.data, priority)) {
ModuleLog(o->i, BLOG_ERROR, "failed to add dns entry");
goto loop_fail2;
}
loop_failed = 0;
loop_fail2:
NCDValNullTermString_Free(&value_nts);
loop_fail1:
NCDValNullTermString_Free(&type_nts);
loop_fail0:
if (loop_failed) {
goto fail1;
}
}
// add to instances
LinkedList1_Append(&g->instances, &o->instances_node);
// set servers
if (!set_servers(g)) {
ModuleLog(o->i, BLOG_ERROR, "failed to set DNS servers");
goto fail2;
}
// signal up
NCDModuleInst_Backend_Up(o->i);
return;
fail2:
LinkedList1_Remove(&g->instances, &o->instances_node);
fail1:
remove_entries(o);
NCDModuleInst_Backend_DeadError(i);
}
static void func_die (void *vo)
{
struct instance *o = vo;
struct global *g = ModuleGlobal(o->i);
// remove from instances
LinkedList1_Remove(&g->instances, &o->instances_node);
// set servers
set_servers(g);
// free servers
remove_entries(o);
NCDModuleInst_Backend_Dead(o->i);
}
static struct NCDModule modules[] = {
{
.type = "net.dns",
.func_new2 = func_new,
.func_die = func_die,
.alloc_size = sizeof(struct instance)
}, {
.type = "net.dns.resolvconf",
.func_new2 = func_new_resolvconf,
.func_die = func_die,
.alloc_size = sizeof(struct instance)
}, {
.type = NULL
}
};
const struct NCDModuleGroup ncdmodule_net_dns = {
.func_globalinit = func_globalinit,
.func_globalfree = func_globalfree,
.modules = modules
};