/*
* libwebsockets - small server side websockets and web server implementation
*
* Copyright (C) 2010 - 2019 Andy Green <andy@warmcat.com>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to
* deal in the Software without restriction, including without limitation the
* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*/
#include "private-lib-core.h"
#include "private-lib-system-dhcpclient.h"
typedef enum {
LDHC_INIT_REBOOT,
LDHC_REBOOTING, /* jitterwait */
LDHC_INIT, /* issue DHCPDISCOVER */
LDHC_SELECTING,
LDHC_REQUESTING,
LDHC_REBINDING,
LDHC_BOUND,
LDHC_RENEWING
} lws_dhcpc_state_t;
enum {
LWSDHCPDISCOVER = 1,
LWSDHCPOFFER,
LWSDHCPREQUEST,
LWSDHCPDECLINE,
LWSDHCPACK,
LWSDHCPNACK,
LWSDHCPRELEASE,
IPV4_PROPOSED = 0,
IPV4_SERVER,
IPV4_ROUTER,
IPV4_SUBNET_MASK,
IPV4_BROADCAST,
IPV4_TIME_SERVER,
IPV4_DNS_SRV_1,
IPV4_DNS_SRV_2,
IPV4_DNS_SRV_3,
IPV4_DNS_SRV_4,
IPV4_LEASE_SECS,
IPV4_REBINDING_SECS,
IPV4_RENEWAL_SECS,
_IPV4_COUNT,
LWSDHCPOPT_PAD = 0,
LWSDHCPOPT_SUBNET_MASK = 1,
LWSDHCPOPT_TIME_OFFSET = 2,
LWSDHCPOPT_ROUTER = 3,
LWSDHCPOPT_TIME_SERVER = 4,
LWSDHCPOPT_NAME_SERVER = 5,
LWSDHCPOPT_DNSERVER = 6,
LWSDHCPOPT_LOG_SERVER = 7,
LWSDHCPOPT_COOKIE_SERVER = 8,
LWSDHCPOPT_LPR_SERVER = 9,
LWSDHCPOPT_IMPRESS_SERVER = 10,
LWSDHCPOPT_RESLOC_SERVER = 11,
LWSDHCPOPT_HOST_NAME = 12,
LWSDHCPOPT_BOOTFILE_SIZE = 13,
LWSDHCPOPT_MERIT_DUMP_FILE = 14,
LWSDHCPOPT_DOMAIN_NAME = 15,
LWSDHCPOPT_SWAP_SERVER = 16,
LWSDHCPOPT_ROOT_PATH = 17,
LWSDHCPOPT_EXTENSIONS_PATH = 18,
LWSDHCPOPT_BROADCAST_ADS = 28,
LWSDHCPOPT_REQUESTED_ADS = 50,
LWSDHCPOPT_LEASE_TIME = 51,
LWSDHCPOPT_OPTION_OVERLOAD = 52,
LWSDHCPOPT_MESSAGE_TYPE = 53,
LWSDHCPOPT_SERVER_ID = 54,
LWSDHCPOPT_PARAM_REQ_LIST = 55,
LWSDHCPOPT_MESSAGE = 56,
LWSDHCPOPT_MAX_DHCP_MSG_SIZE = 57,
LWSDHCPOPT_RENEWAL_TIME = 58, /* AKA T1 */
LWSDHCPOPT_REBINDING_TIME = 59, /* AKA T2 */
LWSDHCPOPT_VENDOR_CLASS_ID = 60,
LWSDHCPOPT_CLIENT_ID = 61,
LWSDHCPOPT_END_OPTIONS = 255
};
typedef struct lws_dhcpc_req {
lws_dll2_t list;
char domain[64];
struct lws_context *context;
lws_sorted_usec_list_t sul_conn;
lws_sorted_usec_list_t sul_write;
dhcpc_cb_t cb; /* cb on completion / failure */
void *opaque; /* ignored by lws, give to cb */
/* these are separated so we can close the bcast one asynchronously */
struct lws *wsi_raw; /* for broadcast */
lws_dhcpc_state_t state;
uint32_t ipv4[_IPV4_COUNT];
uint16_t retry_count_conn;
uint16_t retry_count_write;
uint8_t mac[6];
uint8_t xid[4];
uint8_t af; /* address family */
} lws_dhcpc_req_t;
/* interface name is overallocated here */
static const uint32_t botable2[] = { 1500, 1750, 5000 /* in case dog slow */ };
static const lws_retry_bo_t bo2 = {
botable2, LWS_ARRAY_SIZE(botable2), LWS_RETRY_CONCEAL_ALWAYS, 0, 0, 20 };
static const uint8_t rawdisc[] = {
0x45, 0x00, 0, 0, 0, 0, 0x40, 0, 0x2e, IPPROTO_UDP,
0, 0, 0, 0, 0, 0, 0xff, 0xff, 0xff, 0xff,
0, 68, 0, 67, 0, 0, 0, 0
};
#define LDHC_OP_BOOTREQUEST 1
#define LDHC_OP_BOOTREPLY 2
/*
* IPv4... max total 576
*
* 0 1 2 3
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | op (1) | htype (1) | hlen (1) | hops (1) |
* +---------------+---------------+---------------+---------------+
* | +04 xid (4) |
* +-------------------------------+-------------------------------+
* | +08 secs (2) | +0a flags (2) |
* +-------------------------------+-------------------------------+
* | +0C ciaddr (4) client IP |
* +---------------------------------------------------------------+
* | +10 yiaddr (4) your IP |
* +---------------------------------------------------------------+
* | +14 siaddr (4) server IP |
* +---------------------------------------------------------------+
* | +18 giaddr (4) gateway IP |
* +---------------------------------------------------------------+
* | |
* | +1C chaddr (16) client HWADDR |
* +---------------------------------------------------------------+
* | |
* | +2C sname (64) |
* +---------------------------------------------------------------+
* | |
* | +6C file (128) |
* +---------------------------------------------------------------+
* | |
* | +EC options (variable) |
* +---------------------------------------------------------------+
*/
static const char *dhcp_entry_names[] = {
"proposed ip",
"dhcp server",
"router",
"subnet mask",
"broadcast",
"time server",
"dns1",
"dns2",
"dns3",
"dns4",
"lease secs",
"rebinding secs",
"renewal secs",
};
static void
lws_dhcpc_retry_conn(struct lws_sorted_usec_list *sul)
{
lws_dhcpc_req_t *r = lws_container_of(sul, lws_dhcpc_req_t, sul_conn);
if (r->wsi_raw || !lws_dll2_is_detached(&r->sul_conn.list))
return;
/* create the UDP socket aimed at the server */
r->retry_count_write = 0;
r->wsi_raw = lws_create_adopt_udp(r->context->vhost_system, "0.0.0.0",
68, LWS_CAUDP_PF_PACKET |
LWS_CAUDP_BROADCAST,
"lws-dhcpclient", (const char *)&r[1],
NULL, NULL, &bo2);
lwsl_debug("%s: created wsi_raw: %p\n", __func__, r->wsi_raw);
if (!r->wsi_raw) {
lwsl_err("%s: unable to create udp skt\n", __func__);
lws_retry_sul_schedule(r->context, 0, &r->sul_conn, &bo2,
lws_dhcpc_retry_conn,
&r->retry_count_conn);
return;
}
/* force the network if up */
lws_plat_if_up((const char *)&r[1], r->wsi_raw->desc.sockfd, 0);
lws_plat_if_up((const char *)&r[1], r->wsi_raw->desc.sockfd, 1);
r->wsi_raw->user_space = r;
r->wsi_raw->user_space_externally_allocated = 1;
lws_get_random(r->wsi_raw->context, r->xid, 4);
}
static void
lws_dhcpc_retry_write(struct lws_sorted_usec_list *sul)
{
lws_dhcpc_req_t *r = lws_container_of(sul, lws_dhcpc_req_t, sul_write);
lwsl_debug("%s\n", __func__);
if (r && r->wsi_raw)
lws_callback_on_writable(r->wsi_raw);
}
#if 0
static int
lws_sys_dhcpc_notify_cb(lws_state_manager_t *mgr, lws_state_notify_link_t *l,
int current, int target)
{
lws_dhcpc_req_t *r = lws_container_of(l, lws_dhcpc_req_t, notify_link);
if (target != LWS_SYSTATE_TIME_VALID || v->set_time)
return 0;
/* it's trying to do it ever since the protocol / vhost was set up */
return 1;
}
#endif
static int
lws_dhcpc_prep(uint8_t *start, int bufsiz, lws_dhcpc_req_t *r, int op)
{
uint8_t *p = start;
memset(start, 0, bufsiz);
*p++ = 1;
*p++ = 1;
*p++ = 6; /* sizeof ethernet MAC */
memcpy(p + 1, r->xid, 4);
// p[7] = 0x80; /* broadcast flag */
p += 0x1c - 3;
if (lws_plat_ifname_to_hwaddr(r->wsi_raw->desc.sockfd,
(const char *)&r[1], r->mac, 6) < 0)
return -1;
memcpy(p, r->mac, 6);
p += 16 + 64 + 128;
*p++ = 0x63; /* RFC2132 Magic Cookie indicates start of options */
*p++ = 0x82;
*p++ = 0x53;
*p++ = 0x63;
*p++ = LWSDHCPOPT_MESSAGE_TYPE;
*p++ = 1; /* length */
*p++ = op;
switch (op) {
case LWSDHCPDISCOVER:
*p++ = LWSDHCPOPT_PARAM_REQ_LIST;
*p++ = 4; /* length */
*p++ = 1; /* subnet mask */
*p++ = 3; /* router */
*p++ = 15; /* domain name */
*p++ = 6; /* DNServer */
break;
case LWSDHCPREQUEST:
*p++ = LWSDHCPOPT_REQUESTED_ADS;
*p++ = 4; /* length */
lws_ser_wu32be(p, r->ipv4[IPV4_PROPOSED]);
p += 4;
*p++ = LWSDHCPOPT_SERVER_ID;
*p++ = 4; /* length */
lws_ser_wu32be(p, r->ipv4[IPV4_SERVER]);
p += 4;
break;
}
*p++ = LWSDHCPOPT_END_OPTIONS;
return lws_ptr_diff(p, start);
}
static int
callback_dhcpc(struct lws *wsi, enum lws_callback_reasons reason, void *user,
void *in, size_t len)
{
lws_dhcpc_req_t *r = (lws_dhcpc_req_t *)user;
uint8_t pkt[LWS_PRE + 576], *p = pkt + LWS_PRE, *end;
int n, m;
switch (reason) {
case LWS_CALLBACK_RAW_ADOPT:
lwsl_debug("%s: LWS_CALLBACK_RAW_ADOPT\n", __func__);
lws_callback_on_writable(wsi);
break;
case LWS_CALLBACK_CLIENT_CONNECTION_ERROR:
lwsl_err("%s: udp conn failed\n", __func__);
/* fallthru */
case LWS_CALLBACK_RAW_CLOSE:
lwsl_debug("%s: LWS_CALLBACK_RAW_CLOSE\n", __func__);
if (!r)
break;
r->wsi_raw = NULL;
lws_sul_schedule(r->context, 0, &r->sul_write, NULL,
LWS_SET_TIMER_USEC_CANCEL);
if (r->state != LDHC_BOUND) {
r->state = LDHC_INIT;
lws_retry_sul_schedule(r->context, 0, &r->sul_conn, &bo2,
lws_dhcpc_retry_conn,
&r->retry_count_conn);
}
break;
case LWS_CALLBACK_RAW_RX:
switch (r->state) {
case LDHC_INIT: /* expect DHCPOFFER */
case LDHC_REQUESTING: /* expect DHCPACK */
/*
* We should check carefully if we like what we were
* sent... anything can spam us with crafted replies
*/
if (len < 0x100)
break;
p = (uint8_t *)in + 28; /* skip to UDP payload */
if (p[0] != 2 || p[1] != 1 || p[2] != 6)
break;
if (memcmp(&p[4], r->xid, 4)) /* must be our xid */
break;
if (memcmp(&p[0x1c], r->mac, 6)) /* our netif mac? */
break;
/* the DHCP magic cookie must be in place */
if (lws_ser_ru32be(&p[0xec]) != 0x63825363)
break;
r->ipv4[IPV4_PROPOSED] = lws_ser_ru32be(&p[0x10]);
r->ipv4[IPV4_SERVER] = lws_ser_ru32be(&p[0x14]);
/* it looks legit so far... look at the options */
end = (uint8_t *)in + len;
p += 0xec + 4;
while (p < end) {
uint8_t c = *p++;
uint8_t l = 0;
if (c && c != 0xff) {
/* pad 0 and EOT 0xff have no length */
l = *p++;
if (!l) {
lwsl_err("%s: zero length\n",
__func__);
goto broken;
}
if (p + l > end) {
/* ...nice try... */
lwsl_err("%s: bad len\n",
__func__);
goto broken;
}
}
if (c == 0xff) /* end of options */
break;
m = 0;
switch (c) {
case LWSDHCPOPT_SUBNET_MASK:
n = IPV4_SUBNET_MASK;
goto get_ipv4;
case LWSDHCPOPT_ROUTER:
n = IPV4_ROUTER;
goto get_ipv4;
case LWSDHCPOPT_TIME_SERVER:
n = IPV4_TIME_SERVER;
goto get_ipv4;
case LWSDHCPOPT_BROADCAST_ADS:
n = IPV4_BROADCAST;
goto get_ipv4;
case LWSDHCPOPT_LEASE_TIME:
n = IPV4_LEASE_SECS;
goto get_ipv4;
case LWSDHCPOPT_RENEWAL_TIME: /* AKA T1 */
n = IPV4_RENEWAL_SECS;
goto get_ipv4;
case LWSDHCPOPT_REBINDING_TIME: /* AKA T2 */
n = IPV4_REBINDING_SECS;
goto get_ipv4;
case LWSDHCPOPT_DNSERVER:
if (l & 3)
break;
m = IPV4_DNS_SRV_1;
while (l && m - IPV4_DNS_SRV_1 < 4) {
r->ipv4[m++] = lws_ser_ru32be(p);
l -= 4;
p += 4;
}
break;
case LWSDHCPOPT_DOMAIN_NAME:
m = l;
if (m > (int)sizeof(r->domain) - 1)
m = sizeof(r->domain) - 1;
memcpy(r->domain, p, m);
r->domain[m] = '\0';
break;
case LWSDHCPOPT_MESSAGE_TYPE:
/*
* Confirm this is the right message
* for the state of the negotiation
*/
if (r->state == LDHC_INIT &&
*p != LWSDHCPOFFER)
goto broken;
if (r->state == LDHC_REQUESTING &&
*p != LWSDHCPACK)
goto broken;
break;
default:
break;
}
p += l;
continue;
get_ipv4:
if (l >= 4)
r->ipv4[n] = lws_ser_ru32be(p);
p += l;
continue;
broken:
memset(r->ipv4, 0, sizeof(r->ipv4));
break;
}
#if defined(_DEBUG)
/* dump what we have parsed out */
for (n = 0; n < (int)LWS_ARRAY_SIZE(dhcp_entry_names); n++)
if (n >= IPV4_LEASE_SECS)
lwsl_info("%s: %s: %ds\n", __func__,
dhcp_entry_names[n],
r->ipv4[n]);
else {
m = ntohl(r->ipv4[n]);
lws_write_numeric_address((uint8_t *)&m,
4,(char *)pkt, 20);
lwsl_info("%s: %s: %s\n", __func__,
dhcp_entry_names[n],
pkt);
}
#endif
/*
* Having seen everything in there... do we really feel
* we could use it? Everything critical is there?
*/
if (!r->ipv4[IPV4_PROPOSED] ||
!r->ipv4[IPV4_SERVER] ||
!r->ipv4[IPV4_ROUTER] ||
!r->ipv4[IPV4_SUBNET_MASK] ||
!r->ipv4[IPV4_LEASE_SECS] ||
!r->ipv4[IPV4_DNS_SRV_1]) {
memset(r->ipv4, 0, sizeof(r->ipv4));
break;
}
/*
* Network layout has to be internally consistent...
* DHCP server has to be reachable by broadcast and
* default route has to be on same subnet
*/
if ((r->ipv4[IPV4_PROPOSED] & r->ipv4[IPV4_SUBNET_MASK]) !=
(r->ipv4[IPV4_SERVER] & r->ipv4[IPV4_SUBNET_MASK]))
break;
if ((r->ipv4[IPV4_PROPOSED] & r->ipv4[IPV4_SUBNET_MASK]) !=
(r->ipv4[IPV4_ROUTER] & r->ipv4[IPV4_SUBNET_MASK]))
break;
if (r->state == LDHC_INIT) {
lwsl_info("%s: moving to REQ\n", __func__);
r->state = LDHC_REQUESTING;
lws_callback_on_writable(r->wsi_raw);
break;
}
/*
* that's it... commit to the configuration
*/
/* set up our network interface as offered */
if (lws_plat_ifconfig_ip((const char *)&r[1],
r->wsi_raw->desc.sockfd,
(uint8_t *)&r->ipv4[IPV4_PROPOSED],
(uint8_t *)&r->ipv4[IPV4_SUBNET_MASK],
(uint8_t *)&r->ipv4[IPV4_ROUTER])) {
/*
* Problem setting the IP... maybe something
* transient like racing with NetworkManager?
* Since the sul retries are still around it
* will retry
*/
return -1;
}
/* clear timeouts related to the broadcast socket */
lws_sul_schedule(r->context, 0, &r->sul_write, NULL,
LWS_SET_TIMER_USEC_CANCEL);
lws_sul_schedule(r->context, 0, &r->sul_conn, NULL,
LWS_SET_TIMER_USEC_CANCEL);
lwsl_notice("%s: DHCP configured %s\n", __func__,
(const char *)&r[1]);
r->state = LDHC_BOUND;
lws_state_transition_steps(&wsi->context->mgr_system,
LWS_SYSTATE_OPERATIONAL);
r->cb(r->opaque, r->af,
(uint8_t *)&r->ipv4[IPV4_PROPOSED], 4);
r->wsi_raw = NULL;
return -1; /* close the broadcast wsi */
default:
break;
}
break;
case LWS_CALLBACK_RAW_WRITEABLE:
if (!r)
break;
/*
* UDP is not reliable, it can be locally dropped, or dropped
* by any intermediary or the remote peer. So even though we
* will do the write in a moment, we schedule another request
* for rewrite according to the wsi retry policy.
*
* If the result came before, we'll cancel it in the close flow.
*
* If we have already reached the end of our concealed retries
* in the policy, just close without another write.
*/
if (lws_dll2_is_detached(&r->sul_write.list) &&
lws_retry_sul_schedule_retry_wsi(wsi, &r->sul_write,
lws_dhcpc_retry_write,
&r->retry_count_write)) {
/* we have reached the end of our concealed retries */
lwsl_warn("%s: concealed retries done, failing\n",
__func__);
goto retry_conn;
}
switch (r->state) {
case LDHC_INIT:
n = LWSDHCPDISCOVER;
goto bcast;
case LDHC_REQUESTING:
n = LWSDHCPREQUEST;
/* fallthru */
bcast:
n = lws_dhcpc_prep(p + 28, sizeof(pkt) - LWS_PRE - 28,
r, n);
if (n < 0) {
lwsl_err("%s: failed to prep\n", __func__);
break;
}
m = lws_plat_rawudp_broadcast(p, rawdisc,
LWS_ARRAY_SIZE(rawdisc),
n + 28,
r->wsi_raw->desc.sockfd,
(const char *)&r[1]);
if (m < 0)
lwsl_err("%s: Failed to write dhcp client req: "
"%d %d, errno %d\n", __func__,
n, m, LWS_ERRNO);
break;
default:
break;
}
return 0;
retry_conn:
lws_retry_sul_schedule(wsi->context, 0, &r->sul_conn, &bo2,
lws_dhcpc_retry_conn,
&r->retry_count_conn);
return -1;
default:
break;
}
return 0;
#if 0
cancel_conn_timer:
lws_sul_schedule(r->context, 0, &r->sul_conn, NULL,
LWS_SET_TIMER_USEC_CANCEL);
return 0;
#endif
}
struct lws_protocols lws_system_protocol_dhcpc =
{ "lws-dhcpclient", callback_dhcpc, 0, 128, };
static void
lws_dhcpc_destroy(lws_dhcpc_req_t **pr)
{
lws_dhcpc_req_t *r = *pr;
lws_sul_schedule(r->context, 0, &r->sul_conn, NULL,
LWS_SET_TIMER_USEC_CANCEL);
lws_sul_schedule(r->context, 0, &r->sul_write, NULL,
LWS_SET_TIMER_USEC_CANCEL);
if (r->wsi_raw)
lws_set_timeout(r->wsi_raw, 1, LWS_TO_KILL_ASYNC);
lws_dll2_remove(&r->list);
lws_free_set_NULL(r);
}
int
lws_dhcpc_status(struct lws_context *context, lws_sockaddr46 *sa46)
{
lws_dhcpc_req_t *r;
lws_start_foreach_dll(struct lws_dll2 *, p, context->dhcpc_owner.head) {
r = (lws_dhcpc_req_t *)p;
if (r->state == LDHC_BOUND) {
if (sa46) {
memset(sa46, 0, sizeof(*sa46));
sa46->sa4.sin_family = AF_INET;
sa46->sa4.sin_addr.s_addr = r->ipv4[IPV4_DNS_SRV_1];
}
return 1;
}
} lws_end_foreach_dll(p);
return 0;
}
static lws_dhcpc_req_t *
lws_dhcpc_find(struct lws_context *context, const char *iface, int af)
{
lws_dhcpc_req_t *r;
/* see if we are already looking after this af / iface combination */
lws_start_foreach_dll(struct lws_dll2 *, p, context->dhcpc_owner.head) {
r = (lws_dhcpc_req_t *)p;
if (!strcmp((const char *)&r[1], iface) && af == r->af)
return r; /* yes... */
} lws_end_foreach_dll(p);
return NULL;
}
/*
* Create a persistent dhcp client entry for network interface "iface" and AF
* type "af"
*/
int
lws_dhcpc_request(struct lws_context *context, const char *iface, int af,
dhcpc_cb_t cb, void *opaque)
{
lws_dhcpc_req_t *r = lws_dhcpc_find(context, iface, af);
int n;
/* see if we are already looking after this af / iface combination */
if (r)
return 0;
/* nope... let's create a request object as he asks */
n = strlen(iface);
r = lws_zalloc(sizeof(*r) + n + 1, __func__);
if (!r)
return 1;
memcpy(&r[1], iface, n + 1);
r->af = af;
r->cb = cb;
r->opaque = opaque;
r->context = context;
r->state = LDHC_INIT;
lws_dll2_add_head(&r->list, &context->dhcpc_owner); /* add him to list */
lws_dhcpc_retry_conn(&r->sul_conn);
return 0;
}
/*
* Destroy every DHCP client object related to interface "iface"
*/
static int
_remove_if(struct lws_dll2 *d, void *opaque)
{
lws_dhcpc_req_t *r = lws_container_of(d, lws_dhcpc_req_t, list);
if (!opaque || !strcmp((const char *)&r[1], (const char *)opaque))
lws_dhcpc_destroy(&r);
return 0;
}
int
lws_dhcpc_remove(struct lws_context *context, const char *iface)
{
lws_dll2_foreach_safe(&context->dhcpc_owner, (void *)iface, _remove_if);
return 0;
}