BadVPN – Rev 1
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/**
* @file net_ipv4_dhcp.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
*
* DHCP client module.
*
* Synopsis:
* net.ipv4.dhcp(string ifname [, list opts])
*
* Description:
* Runs a DHCP client on a network interface. When an address is obtained,
* transitions up (but does not assign anything). If the lease times out,
* transitions down.
* The interface must already be up.
* Supported options (in the opts argument):
* - "hostname", (string value): send this hostname to the DHCP server
* - "vendorclassid", (string value): send this vendor class identifier
* - "auto_clientid": send a client identifier generated from the MAC address
*
* Variables:
* string addr - assigned IP address ("A.B.C.D")
* string prefix - address prefix length ("N")
* string cidr_addr - address and prefix in CIDR notation ("A.B.C.D/N")
* string gateway - router address ("A.B.C.D"), or "none" if not provided
* list(string) dns_servers - DNS server addresses ("A.B.C.D" ...)
* string server_mac - MAC address of the DHCP server (6 two-digit caps hexadecimal values
* separated with colons, e.g."AB:CD:EF:01:02:03")
*/
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <misc/debug.h>
#include <misc/ipaddr.h>
#include <dhcpclient/BDHCPClient.h>
#include <ncd/module_common.h>
#include <generated/blog_channel_ncd_net_ipv4_dhcp.h>
struct instance {
NCDModuleInst *i;
BDHCPClient dhcp;
int up;
};
static void instance_free (struct instance *o, int is_error);
static void dhcp_handler (struct instance *o, int event)
{
switch (event) {
case BDHCPCLIENT_EVENT_UP: {
ASSERT(!o->up)
o->up = 1;
NCDModuleInst_Backend_Up(o->i);
} break;
case BDHCPCLIENT_EVENT_DOWN: {
ASSERT(o->up)
o->up = 0;
NCDModuleInst_Backend_Down(o->i);
} break;
case BDHCPCLIENT_EVENT_ERROR: {
instance_free(o, 1);
return;
} break;
default: ASSERT(0);
}
}
static void func_new (void *vo, NCDModuleInst *i, const struct NCDModuleInst_new_params *params)
{
struct instance *o = vo;
o->i = i;
// check arguments
NCDValRef ifname_arg;
NCDValRef opts_arg = NCDVal_NewInvalid();
if (!NCDVal_ListRead(params->args, 1, &ifname_arg) && !NCDVal_ListRead(params->args, 2, &ifname_arg, &opts_arg)) {
ModuleLog(o->i, BLOG_ERROR, "wrong arity");
goto fail0;
}
if (!NCDVal_IsStringNoNulls(ifname_arg) || (!NCDVal_IsInvalid(opts_arg) && !NCDVal_IsList(opts_arg))) {
ModuleLog(o->i, BLOG_ERROR, "wrong type");
goto fail0;
}
NCDValNullTermString hostname_nts = NCDValNullTermString_NewDummy();
NCDValNullTermString vendorclassid_nts = NCDValNullTermString_NewDummy();
struct BDHCPClient_opts opts = {};
// read options
size_t count = NCDVal_IsInvalid(opts_arg) ? 0 : NCDVal_ListCount(opts_arg);
for (size_t j = 0; j < count; j++) {
NCDValRef opt = NCDVal_ListGet(opts_arg, j);
// read name
if (!NCDVal_IsString(opt)) {
ModuleLog(o->i, BLOG_ERROR, "wrong option name type");
goto fail1;
}
if (NCDVal_StringEquals(opt, "hostname") || NCDVal_StringEquals(opt, "vendorclassid")) {
int is_hostname = NCDVal_StringEquals(opt, "hostname");
// read value
if (j == count) {
ModuleLog(o->i, BLOG_ERROR, "option value missing");
goto fail1;
}
NCDValRef val = NCDVal_ListGet(opts_arg, j + 1);
if (!NCDVal_IsStringNoNulls(val)) {
ModuleLog(o->i, BLOG_ERROR, "wrong option value type");
goto fail1;
}
// null terminate
NCDValNullTermString nts;
if (!NCDVal_StringNullTerminate(val, &nts)) {
ModuleLog(o->i, BLOG_ERROR, "NCDVal_StringNullTerminate failed");
goto fail1;
}
NCDValNullTermString *nts_ptr = (is_hostname ? &hostname_nts : &vendorclassid_nts);
NCDValNullTermString_Free(nts_ptr);
*nts_ptr = nts;
if (is_hostname) {
opts.hostname = nts.data;
} else {
opts.vendorclassid = nts.data;
}
j++;
}
else if (NCDVal_StringEquals(opt, "auto_clientid")) {
opts.auto_clientid = 1;
}
else {
ModuleLog(o->i, BLOG_ERROR, "unknown option name");
goto fail1;
}
}
// null terminate ifname
NCDValNullTermString ifname_nts;
if (!NCDVal_StringNullTerminate(ifname_arg, &ifname_nts)) {
ModuleLog(i, BLOG_ERROR, "NCDVal_StringNullTerminate failed");
goto fail1;
}
// init DHCP
int res = BDHCPClient_Init(&o->dhcp, ifname_nts.data, opts, o->i->params->iparams->reactor, o->i->params->iparams->random2, (BDHCPClient_handler)dhcp_handler, o);
NCDValNullTermString_Free(&ifname_nts);
if (!res) {
ModuleLog(o->i, BLOG_ERROR, "BDHCPClient_Init failed");
goto fail1;
}
// set not up
o->up = 0;
// free options nts's
NCDValNullTermString_Free(&hostname_nts);
NCDValNullTermString_Free(&vendorclassid_nts);
return;
fail1:
NCDValNullTermString_Free(&hostname_nts);
NCDValNullTermString_Free(&vendorclassid_nts);
fail0:
NCDModuleInst_Backend_DeadError(i);
}
static void instance_free (struct instance *o, int is_error)
{
// free DHCP
BDHCPClient_Free(&o->dhcp);
if (is_error) {
NCDModuleInst_Backend_DeadError(o->i);
} else {
NCDModuleInst_Backend_Dead(o->i);
}
}
static void func_die (void *vo)
{
struct instance *o = vo;
instance_free(o, 0);
}
static int func_getvar (void *vo, const char *name, NCDValMem *mem, NCDValRef *out)
{
struct instance *o = vo;
ASSERT(o->up)
if (!strcmp(name, "addr")) {
uint32_t addr;
BDHCPClient_GetClientIP(&o->dhcp, &addr);
char str[IPADDR_PRINT_MAX];
ipaddr_print_addr(addr, str);
*out = NCDVal_NewString(mem, str);
return 1;
}
if (!strcmp(name, "prefix")) {
uint32_t addr;
BDHCPClient_GetClientIP(&o->dhcp, &addr);
uint32_t mask;
BDHCPClient_GetClientMask(&o->dhcp, &mask);
struct ipv4_ifaddr ifaddr;
if (!ipaddr_ipv4_ifaddr_from_addr_mask(addr, mask, &ifaddr)) {
ModuleLog(o->i, BLOG_ERROR, "bad netmask");
return 0;
}
char str[10];
sprintf(str, "%d", ifaddr.prefix);
*out = NCDVal_NewString(mem, str);
return 1;
}
if (!strcmp(name, "cidr_addr")) {
uint32_t addr;
BDHCPClient_GetClientIP(&o->dhcp, &addr);
uint32_t mask;
BDHCPClient_GetClientMask(&o->dhcp, &mask);
struct ipv4_ifaddr ifaddr;
if (!ipaddr_ipv4_ifaddr_from_addr_mask(addr, mask, &ifaddr)) {
ModuleLog(o->i, BLOG_ERROR, "bad netmask");
return 0;
}
char str[IPADDR_PRINT_MAX];
ipaddr_print_ifaddr(ifaddr, str);
*out = NCDVal_NewString(mem, str);
return 1;
}
if (!strcmp(name, "gateway")) {
char str[IPADDR_PRINT_MAX];
uint32_t addr;
if (!BDHCPClient_GetRouter(&o->dhcp, &addr)) {
strcpy(str, "none");
} else {
ipaddr_print_addr(addr, str);
}
*out = NCDVal_NewString(mem, str);
return 1;
}
if (!strcmp(name, "dns_servers")) {
uint32_t servers[BDHCPCLIENT_MAX_DOMAIN_NAME_SERVERS];
int num_servers = BDHCPClient_GetDNS(&o->dhcp, servers, BDHCPCLIENT_MAX_DOMAIN_NAME_SERVERS);
*out = NCDVal_NewList(mem, num_servers);
if (NCDVal_IsInvalid(*out)) {
goto fail;
}
for (int i = 0; i < num_servers; i++) {
char str[IPADDR_PRINT_MAX];
ipaddr_print_addr(servers[i], str);
NCDValRef server = NCDVal_NewString(mem, str);
if (NCDVal_IsInvalid(server)) {
goto fail;
}
if (!NCDVal_ListAppend(*out, server)) {
goto fail;
}
}
return 1;
}
if (!strcmp(name, "server_mac")) {
uint8_t mac[6];
BDHCPClient_GetServerMAC(&o->dhcp, mac);
char str[18];
sprintf(str, "%02"PRIX8":%02"PRIX8":%02"PRIX8":%02"PRIX8":%02"PRIX8":%02"PRIX8,
mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]);
*out = NCDVal_NewString(mem, str);
return 1;
}
return 0;
fail:
*out = NCDVal_NewInvalid();
return 1;
}
static struct NCDModule modules[] = {
{
.type = "net.ipv4.dhcp",
.func_new2 = func_new,
.func_die = func_die,
.func_getvar = func_getvar,
.alloc_size = sizeof(struct instance)
}, {
.type = NULL
}
};
const struct NCDModuleGroup ncdmodule_net_ipv4_dhcp = {
.modules = modules
};