/*
* dhcpcd - DHCP client daemon
* Copyright (c) 2006-2015 Roy Marples <roy@marples.name>
* All rights reserved
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 OR CONTRIBUTORS 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.
*/
#include <sys/param.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <arpa/inet.h>
#include <net/if.h>
#include <net/route.h>
#include <netinet/if_ether.h>
#include <netinet/in_systm.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#define __FAVOR_BSD /* Nasty glibc hack so we can use BSD semantics for UDP */
#include <netinet/udp.h>
#undef __FAVOR_BSD
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <inttypes.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#define ELOOP_QUEUE 2
#include "config.h"
#include "arp.h"
#include "common.h"
#include "dhcp.h"
#include "dhcpcd.h"
#include "dhcp-common.h"
#include "duid.h"
#include "eloop.h"
#include "if.h"
#include "ipv4.h"
#include "ipv4ll.h"
#include "rpc-interface.h"
#include "script.h"
#define DAD "Duplicate address detected"
#define DHCP_MIN_LEASE 20
#define IPV4A ADDRIPV4 | ARRAY
#define IPV4R ADDRIPV4 | REQUEST
/* We should define a maximum for the NAK exponential backoff */
#define NAKOFF_MAX 60
/* Wait N nanoseconds between sending a RELEASE and dropping the address.
* This gives the kernel enough time to actually send it. */
#define RELEASE_DELAY_S 0
#define RELEASE_DELAY_NS 10000000
#ifndef IPDEFTTL
#define IPDEFTTL 64 /* RFC1340 */
#endif
struct dhcp_op {
uint8_t value;
const char *name;
};
static const struct dhcp_op dhcp_ops[] = {
{ DHCP_DISCOVER, "DISCOVER" },
{ DHCP_OFFER, "OFFER" },
{ DHCP_REQUEST, "REQUEST" },
{ DHCP_DECLINE, "DECLINE" },
{ DHCP_ACK, "ACK" },
{ DHCP_NAK, "NAK" },
{ DHCP_RELEASE, "RELEASE" },
{ DHCP_INFORM, "INFORM" },
{ DHCP_FORCERENEW, "DHCP_FORCERENEW"},
{ 0, NULL }
};
static const char * const dhcp_params[] = {
"ip_address",
"subnet_cidr",
"network_number",
"filename",
"server_name",
NULL
};
struct udp_dhcp_packet
{
struct ip ip;
struct udphdr udp;
struct dhcp_message dhcp;
};
static const size_t udp_dhcp_len = sizeof(struct udp_dhcp_packet);
static int dhcp_open(struct interface *ifp);
void
dhcp_printoptions(const struct dhcpcd_ctx *ctx,
const struct dhcp_opt *opts, size_t opts_len)
{
const char * const *p;
size_t i, j;
const struct dhcp_opt *opt, *opt2;
int cols;
for (p = dhcp_params; *p; p++)
printf(" %s\n", *p);
for (i = 0, opt = ctx->dhcp_opts; i < ctx->dhcp_opts_len; i++, opt++) {
for (j = 0, opt2 = opts; j < opts_len; j++, opt2++)
if (opt->option == opt2->option)
break;
if (j == opts_len) {
cols = printf("%03d %s", opt->option, opt->var);
dhcp_print_option_encoding(opt, cols);
}
}
for (i = 0, opt = opts; i < opts_len; i++, opt++) {
cols = printf("%03d %s", opt->option, opt->var);
dhcp_print_option_encoding(opt, cols);
}
}
#define get_option_raw(ctx, dhcp, opt) get_option(ctx, dhcp, opt, NULL)
static const uint8_t *
get_option(struct dhcpcd_ctx *ctx,
const struct dhcp_message *dhcp, unsigned int opt, size_t *len)
{
const uint8_t *p = dhcp->options;
const uint8_t *e = p + sizeof(dhcp->options);
uint8_t l, ol = 0;
uint8_t o = 0;
uint8_t overl = 0;
uint8_t *bp = NULL;
const uint8_t *op = NULL;
size_t bl = 0;
/* Check we have the magic cookie */
if (dhcp->cookie != htonl(MAGIC_COOKIE)) {
errno = ENOTSUP;
return NULL;
}
/* DHCP options are in TLV format with T and L each being a single
* bytes. In general, here we have p -> T, ol=p+1 -> L, op -> V.
* We must make sure there is enough room to read both T and L.
*/
while (p + 1 < e) {
o = *p++;
if (o == opt) {
if (op) {
if (!ctx->opt_buffer) {
ctx->opt_buffer =
malloc(DHCP_OPTION_LEN +
BOOTFILE_LEN + SERVERNAME_LEN);
if (ctx->opt_buffer == NULL)
return NULL;
}
if (!bp)
bp = ctx->opt_buffer;
memcpy(bp, op, ol);
bp += ol;
}
ol = (p + *p < e) ? *p : e - (p + 1);
if (p + ol > e) {
errno = EINVAL;
return NULL;
}
op = p + 1;
bl += ol;
}
switch (o) {
case DHO_PAD:
continue;
case DHO_END:
if (overl & 1) {
/* bit 1 set means parse boot file */
overl = (uint8_t)(overl & ~1);
p = dhcp->bootfile;
e = p + sizeof(dhcp->bootfile);
} else if (overl & 2) {
/* bit 2 set means parse server name */
overl = (uint8_t)(overl & ~2);
p = dhcp->servername;
e = p + sizeof(dhcp->servername);
} else
goto exit;
break;
case DHO_OPTIONSOVERLOADED:
/* Ensure we only get this option once by setting
* the last bit as well as the value.
* This is valid because only the first two bits
* actually mean anything in RFC2132 Section 9.3 */
if (!overl)
overl = 0x80 | p[1];
break;
}
l = *p++;
p += l;
}
exit:
if (len)
*len = bl;
if (bp) {
memcpy(bp, op, ol);
return (const uint8_t *)ctx->opt_buffer;
}
if (op)
return op;
errno = ENOENT;
return NULL;
}
int
get_option_addr(struct dhcpcd_ctx *ctx,
struct in_addr *a, const struct dhcp_message *dhcp,
uint8_t option)
{
const uint8_t *p;
size_t len;
p = get_option(ctx, dhcp, option, &len);
if (!p || len < (ssize_t)sizeof(a->s_addr))
return -1;
memcpy(&a->s_addr, p, sizeof(a->s_addr));
return 0;
}
static int
get_option_uint32(struct dhcpcd_ctx *ctx,
uint32_t *i, const struct dhcp_message *dhcp, uint8_t option)
{
const uint8_t *p;
size_t len;
uint32_t d;
p = get_option(ctx, dhcp, option, &len);
if (!p || len < (ssize_t)sizeof(d))
return -1;
memcpy(&d, p, sizeof(d));
if (i)
*i = ntohl(d);
return 0;
}
static int
get_option_uint8(struct dhcpcd_ctx *ctx,
uint8_t *i, const struct dhcp_message *dhcp, uint8_t option)
{
const uint8_t *p;
size_t len;
p = get_option(ctx, dhcp, option, &len);
if (!p || len < (ssize_t)sizeof(*p))
return -1;
if (i)
*i = *(p);
return 0;
}
ssize_t
decode_rfc3442(char *out, size_t len, const uint8_t *p, size_t pl)
{
const uint8_t *e;
size_t bytes = 0, ocets;
int b;
uint8_t cidr;
struct in_addr addr;
char *o = out;
/* Minimum is 5 -first is CIDR and a router length of 4 */
if (pl < 5) {
errno = EINVAL;
return -1;
}
e = p + pl;
while (p < e) {
cidr = *p++;
if (cidr > 32) {
errno = EINVAL;
return -1;
}
ocets = (size_t)(cidr + 7) / NBBY;
if (p + 4 + ocets > e) {
errno = ERANGE;
return -1;
}
if (!out) {
p += 4 + ocets;
bytes += ((4 * 4) * 2) + 4;
continue;
}
if ((((4 * 4) * 2) + 4) > len) {
errno = ENOBUFS;
return -1;
}
if (o != out) {
*o++ = ' ';
len--;
}
/* If we have ocets then we have a destination and netmask */
if (ocets > 0) {
addr.s_addr = 0;
memcpy(&addr.s_addr, p, ocets);
b = snprintf(o, len, "%s/%d", inet_ntoa(addr), cidr);
p += ocets;
} else
b = snprintf(o, len, "0.0.0.0/0");
o += b;
len -= (size_t)b;
/* Finally, snag the router */
memcpy(&addr.s_addr, p, 4);
p += 4;
b = snprintf(o, len, " %s", inet_ntoa(addr));
o += b;
len -= (size_t)b;
}
if (out)
return o - out;
return (ssize_t)bytes;
}
static struct rt_head *
decode_rfc3442_rt(struct dhcpcd_ctx *ctx, const uint8_t *data, size_t dl)
{
const uint8_t *p = data;
const uint8_t *e;
uint8_t cidr;
size_t ocets;
struct rt_head *routes;
struct rt *rt = NULL;
/* Minimum is 5 -first is CIDR and a router length of 4 */
if (dl < 5)
return NULL;
routes = malloc(sizeof(*routes));
TAILQ_INIT(routes);
e = p + dl;
while (p < e) {
cidr = *p++;
if (cidr > 32) {
ipv4_freeroutes(routes);
errno = EINVAL;
return NULL;
}
ocets = (size_t)(cidr + 7) / NBBY;
if (p + 4 + ocets > e) {
ipv4_freeroutes(routes);
errno = ERANGE;
return NULL;
}
rt = calloc(1, sizeof(*rt));
if (rt == NULL) {
logger(ctx, LOG_ERR, "%s: %m", __func__);
ipv4_freeroutes(routes);
return NULL;
}
TAILQ_INSERT_TAIL(routes, rt, next);
/* If we have ocets then we have a destination and netmask */
if (ocets > 0) {
memcpy(&rt->dest.s_addr, p, ocets);
p += ocets;
rt->net.s_addr = htonl(~0U << (32 - cidr));
}
/* Finally, snag the router */
memcpy(&rt->gate.s_addr, p, 4);
p += 4;
}
return routes;
}
char *
decode_rfc3361(const uint8_t *data, size_t dl)
{
uint8_t enc;
size_t l;
ssize_t r;
char *sip = NULL;
struct in_addr addr;
char *p;
if (dl < 2) {
errno = EINVAL;
return 0;
}
enc = *data++;
dl--;
switch (enc) {
case 0:
if ((r = decode_rfc3397(NULL, 0, data, dl)) > 0) {
l = (size_t)r;
sip = malloc(l);
if (sip == NULL)
return 0;
decode_rfc3397(sip, l, data, dl);
}
break;
case 1:
if (dl == 0 || dl % 4 != 0) {
errno = EINVAL;
break;
}
addr.s_addr = INADDR_BROADCAST;
l = ((dl / sizeof(addr.s_addr)) * ((4 * 4) + 1)) + 1;
sip = p = malloc(l);
if (sip == NULL)
return 0;
while (dl != 0) {
memcpy(&addr.s_addr, data, sizeof(addr.s_addr));
data += sizeof(addr.s_addr);
p += snprintf(p, l - (size_t)(p - sip),
"%s ", inet_ntoa(addr));
dl -= sizeof(addr.s_addr);
}
*--p = '\0';
break;
default:
errno = EINVAL;
return 0;
}
return sip;
}
/* Decode an RFC5969 6rd order option into a space
* separated string. Returns length of string (including
* terminating zero) or zero on error. */
ssize_t
decode_rfc5969(char *out, size_t len, const uint8_t *p, size_t pl)
{
uint8_t ipv4masklen, ipv6prefixlen;
uint8_t ipv6prefix[16];
uint8_t br[4];
int i;
ssize_t b, bytes = 0;
if (pl < 22) {
errno = EINVAL;
return 0;
}
ipv4masklen = *p++;
pl--;
ipv6prefixlen = *p++;
pl--;
for (i = 0; i < 16; i++) {
ipv6prefix[i] = *p++;
pl--;
}
if (out) {
b= snprintf(out, len,
"%d %d "
"%02x%02x:%02x%02x:"
"%02x%02x:%02x%02x:"
"%02x%02x:%02x%02x:"
"%02x%02x:%02x%02x",
ipv4masklen, ipv6prefixlen,
ipv6prefix[0], ipv6prefix[1], ipv6prefix[2], ipv6prefix[3],
ipv6prefix[4], ipv6prefix[5], ipv6prefix[6], ipv6prefix[7],
ipv6prefix[8], ipv6prefix[9], ipv6prefix[10],ipv6prefix[11],
ipv6prefix[12],ipv6prefix[13],ipv6prefix[14], ipv6prefix[15]
);
len -= (size_t)b;
out += b;
bytes += b;
} else {
bytes += 16 * 2 + 8 + 2 + 1 + 2;
}
while (pl >= 4) {
br[0] = *p++;
br[1] = *p++;
br[2] = *p++;
br[3] = *p++;
pl -= 4;
if (out) {
b= snprintf(out, len, " %d.%d.%d.%d",
br[0], br[1], br[2], br[3]);
len -= (size_t)b;
out += b;
bytes += b;
} else {
bytes += (4 * 4);
}
}
return bytes;
}
static char *
get_option_string(struct dhcpcd_ctx *ctx,
const struct dhcp_message *dhcp, uint8_t option)
{
size_t len;
const uint8_t *p;
char *s;
p = get_option(ctx, dhcp, option, &len);
if (!p || len == 0 || *p == '\0')
return NULL;
s = malloc(sizeof(char) * (len + 1));
if (s) {
memcpy(s, p, len);
s[len] = '\0';
}
return s;
}
/* This calculates the netmask that we should use for static routes.
* This IS different from the calculation used to calculate the netmask
* for an interface address. */
static uint32_t
route_netmask(uint32_t ip_in)
{
/* used to be unsigned long - check if error */
uint32_t p = ntohl(ip_in);
uint32_t t;
if (IN_CLASSA(p))
t = ~IN_CLASSA_NET;
else {
if (IN_CLASSB(p))
t = ~IN_CLASSB_NET;
else {
if (IN_CLASSC(p))
t = ~IN_CLASSC_NET;
else
t = 0;
}
}
while (t & p)
t >>= 1;
return (htonl(~t));
}
/* We need to obey routing options.
* If we have a CSR then we only use that.
* Otherwise we add static routes and then routers. */
struct rt_head *
get_option_routes(struct interface *ifp, const struct dhcp_message *dhcp)
{
struct if_options *ifo = ifp->options;
const uint8_t *p;
const uint8_t *e;
struct rt_head *routes = NULL;
struct rt *route = NULL;
size_t len;
const char *csr = "";
/* If we have CSR's then we MUST use these only */
if (!has_option_mask(ifo->nomask, DHO_CSR))
p = get_option(ifp->ctx, dhcp, DHO_CSR, &len);
else
p = NULL;
/* Check for crappy MS option */
if (!p && !has_option_mask(ifo->nomask, DHO_MSCSR)) {
p = get_option(ifp->ctx, dhcp, DHO_MSCSR, &len);
if (p)
csr = "MS ";
}
if (p) {
routes = decode_rfc3442_rt(ifp->ctx, p, len);
if (routes) {
const struct dhcp_state *state;
state = D_CSTATE(ifp);
if (!(ifo->options & DHCPCD_CSR_WARNED) &&
!(state->added & STATE_FAKE))
{
logger(ifp->ctx, LOG_DEBUG,
"%s: using %sClassless Static Routes",
ifp->name, csr);
ifo->options |= DHCPCD_CSR_WARNED;
}
return routes;
}
}
/* OK, get our static routes first. */
routes = malloc(sizeof(*routes));
if (routes == NULL) {
logger(ifp->ctx, LOG_ERR, "%s: %m", __func__);
return NULL;
}
TAILQ_INIT(routes);
if (!has_option_mask(ifo->nomask, DHO_STATICROUTE))
p = get_option(ifp->ctx, dhcp, DHO_STATICROUTE, &len);
else
p = NULL;
/* RFC 2131 Section 5.8 states length MUST be in multiples of 8 */
if (p && len % 8 == 0) {
e = p + len;
while (p < e) {
if ((route = calloc(1, sizeof(*route))) == NULL) {
logger(ifp->ctx, LOG_ERR, "%s: %m", __func__);
ipv4_freeroutes(routes);
return NULL;
}
memcpy(&route->dest.s_addr, p, 4);
p += 4;
memcpy(&route->gate.s_addr, p, 4);
p += 4;
/* RFC 2131 Section 5.8 states default route is
* illegal */
if (route->dest.s_addr == htonl(INADDR_ANY)) {
errno = EINVAL;
free(route);
continue;
}
route->net.s_addr = route_netmask(route->dest.s_addr);
TAILQ_INSERT_TAIL(routes, route, next);
}
}
/* Now grab our routers */
if (!has_option_mask(ifo->nomask, DHO_ROUTER))
p = get_option(ifp->ctx, dhcp, DHO_ROUTER, &len);
else
p = NULL;
if (p) {
e = p + len;
while (p < e) {
if ((route = calloc(1, sizeof(*route))) == NULL) {
logger(ifp->ctx, LOG_ERR, "%s: %m", __func__);
ipv4_freeroutes(routes);
return NULL;
}
memcpy(&route->gate.s_addr, p, 4);
p += 4;
TAILQ_INSERT_TAIL(routes, route, next);
}
}
return routes;
}
#define PUTADDR(_type, _val) \
{ \
*p++ = _type; \
*p++ = 4; \
memcpy(p, &_val.s_addr, 4); \
p += 4; \
}
int
dhcp_message_add_addr(struct dhcp_message *dhcp,
uint8_t type, struct in_addr addr)
{
uint8_t *p;
size_t len;
p = dhcp->options;
while (*p != DHO_END) {
p++;
p += *p + 1;
}
len = (size_t)(p - (uint8_t *)dhcp);
if (len + 6 > sizeof(*dhcp)) {
errno = ENOMEM;
return -1;
}
PUTADDR(type, addr);
*p = DHO_END;
return 0;
}
ssize_t
make_message(struct dhcp_message **message,
const struct interface *ifp,
uint8_t type)
{
struct dhcp_message *dhcp;
uint8_t *m, *lp, *p, *auth;
uint8_t *n_params = NULL, auth_len;
uint32_t ul;
uint16_t sz;
size_t len, i;
const struct dhcp_opt *opt;
struct if_options *ifo = ifp->options;
const struct dhcp_state *state = D_CSTATE(ifp);
const struct dhcp_lease *lease = &state->lease;
time_t up = uptime() - state->start_uptime;
char hbuf[HOSTNAME_MAX_LEN + 1];
const char *hostname;
const struct vivco *vivco;
dhcp = calloc(1, sizeof (*dhcp));
if (dhcp == NULL)
return -1;
m = (uint8_t *)dhcp;
p = dhcp->options;
if ((type == DHCP_INFORM || type == DHCP_RELEASE ||
(type == DHCP_REQUEST &&
state->net.s_addr == lease->net.s_addr &&
(state->new == NULL ||
state->new->cookie == htonl(MAGIC_COOKIE)))))
{
dhcp->ciaddr = state->addr.s_addr;
/* In-case we haven't actually configured the address yet */
if (type == DHCP_INFORM && state->addr.s_addr == 0)
dhcp->ciaddr = lease->addr.s_addr;
}
dhcp->op = DHCP_BOOTREQUEST;
dhcp->hwtype = (uint8_t)ifp->family;
switch (ifp->family) {
case ARPHRD_ETHER:
case ARPHRD_IEEE802:
dhcp->hwlen = (uint8_t)ifp->hwlen;
memcpy(&dhcp->chaddr, &ifp->hwaddr, ifp->hwlen);
break;
}
if (ifo->options & DHCPCD_BROADCAST &&
dhcp->ciaddr == 0 &&
type != DHCP_DECLINE &&
type != DHCP_RELEASE)
dhcp->flags = htons(BROADCAST_FLAG);
if (type != DHCP_DECLINE && type != DHCP_RELEASE) {
if (up < 0 || up > (time_t)UINT16_MAX)
dhcp->secs = htons((uint16_t)UINT16_MAX);
else
dhcp->secs = htons((uint16_t)up);
}
dhcp->xid = htonl(state->xid);
dhcp->cookie = htonl(MAGIC_COOKIE);
if (!(ifo->options & DHCPCD_BOOTP)) {
*p++ = DHO_MESSAGETYPE;
*p++ = 1;
*p++ = type;
}
if (state->clientid) {
*p++ = DHO_CLIENTID;
memcpy(p, state->clientid, (size_t)state->clientid[0] + 1);
p += state->clientid[0] + 1;
}
if (lease->addr.s_addr && lease->cookie == htonl(MAGIC_COOKIE)) {
if (type == DHCP_DECLINE ||
(type == DHCP_REQUEST &&
lease->addr.s_addr != state->addr.s_addr))
{
PUTADDR(DHO_IPADDRESS, lease->addr);
if (lease->server.s_addr)
PUTADDR(DHO_SERVERID, lease->server);
}
if (type == DHCP_RELEASE) {
if (lease->server.s_addr)
PUTADDR(DHO_SERVERID, lease->server);
}
}
if (type == DHCP_DECLINE) {
*p++ = DHO_MESSAGE;
len = strlen(DAD);
*p++ = (uint8_t)len;
memcpy(p, DAD, len);
p += len;
}
if (type == DHCP_DISCOVER &&
!(ifp->ctx->options & DHCPCD_TEST) &&
has_option_mask(ifo->requestmask, DHO_RAPIDCOMMIT))
{
/* RFC 4039 Section 3 */
*p++ = DHO_RAPIDCOMMIT;
*p++ = 0;
}
if (type == DHCP_DISCOVER && ifo->options & DHCPCD_REQUEST)
PUTADDR(DHO_IPADDRESS, ifo->req_addr);
/* RFC 2563 Auto Configure */
if (type == DHCP_DISCOVER && ifo->options & DHCPCD_IPV4LL) {
*p++ = DHO_AUTOCONFIGURE;
*p++ = 1;
*p++ = 1;
}
if (type == DHCP_DISCOVER ||
type == DHCP_INFORM ||
type == DHCP_REQUEST)
{
if (!(ifo->options & DHCPCD_BOOTP)) {
int mtu;
*p++ = DHO_MAXMESSAGESIZE;
*p++ = 2;
mtu = if_getmtu(ifp->name);
if (mtu < MTU_MIN) {
if (if_setmtu(ifp->name, MTU_MIN) == 0)
sz = MTU_MIN;
} else if (mtu > MTU_MAX) {
/* Even though our MTU could be greater than
* MTU_MAX (1500) dhcpcd does not presently
* handle DHCP packets any bigger. */
mtu = MTU_MAX;
}
sz = htons((uint16_t)mtu);
memcpy(p, &sz, 2);
p += 2;
}
if (ifo->userclass[0]) {
*p++ = DHO_USERCLASS;
memcpy(p, ifo->userclass,
(size_t)ifo->userclass[0] + 1);
p += ifo->userclass[0] + 1;
}
if (ifo->vendorclassid[0]) {
*p++ = DHO_VENDORCLASSID;
memcpy(p, ifo->vendorclassid,
(size_t)ifo->vendorclassid[0] + 1);
p += ifo->vendorclassid[0] + 1;
}
if (type != DHCP_INFORM) {
if (ifo->leasetime != 0) {
*p++ = DHO_LEASETIME;
*p++ = 4;
ul = htonl(ifo->leasetime);
memcpy(p, &ul, 4);
p += 4;
}
}
if (ifo->hostname[0] == '\0')
hostname = get_hostname(hbuf, sizeof(hbuf),
ifo->options & DHCPCD_HOSTNAME_SHORT ? 1 : 0);
else
hostname = ifo->hostname;
/*
* RFC4702 3.1 States that if we send the Client FQDN option
* then we MUST NOT also send the Host Name option.
* Technically we could, but that is not RFC conformant and
* also seems to break some DHCP server implemetations such as
* Windows. On the other hand, ISC dhcpd is just as non RFC
* conformant by not accepting a partially qualified FQDN.
*/
if (ifo->fqdn != FQDN_DISABLE) {
/* IETF DHC-FQDN option (81), RFC4702 */
*p++ = DHO_FQDN;
lp = p;
*p++ = 3;
/*
* Flags: 0000NEOS
* S: 1 => Client requests Server to update
* a RR in DNS as well as PTR
* O: 1 => Server indicates to client that
* DNS has been updated
* E: 1 => Name data is DNS format
* N: 1 => Client requests Server to not
* update DNS
*/
if (hostname)
*p++ = (uint8_t)((ifo->fqdn & 0x09) | 0x04);
else
*p++ = (FQDN_NONE & 0x09) | 0x04;
*p++ = 0; /* from server for PTR RR */
*p++ = 0; /* from server for A RR if S=1 */
if (hostname) {
i = encode_rfc1035(hostname, p);
*lp = (uint8_t)(*lp + i);
p += i;
}
} else if (ifo->options & DHCPCD_HOSTNAME && hostname) {
*p++ = DHO_HOSTNAME;
len = strlen(hostname);
*p++ = (uint8_t)len;
memcpy(p, hostname, len);
p += len;
}
/* vendor is already encoded correctly, so just add it */
if (ifo->vendor[0]) {
*p++ = DHO_VENDOR;
memcpy(p, ifo->vendor, (size_t)ifo->vendor[0] + 1);
p += ifo->vendor[0] + 1;
}
if ((ifo->auth.options & DHCPCD_AUTH_SENDREQUIRE) !=
DHCPCD_AUTH_SENDREQUIRE)
{
/* We support HMAC-MD5 */
*p++ = DHO_FORCERENEW_NONCE;
*p++ = 1;
*p++ = AUTH_ALG_HMAC_MD5;
}
if (ifo->vivco_len) {
*p++ = DHO_VIVCO;
lp = p++;
*lp = sizeof(ul);
ul = htonl(ifo->vivco_en);
memcpy(p, &ul, sizeof(ul));
p += sizeof(ul);
for (i = 0, vivco = ifo->vivco;
i < ifo->vivco_len;
i++, vivco++)
{
len = (size_t)(p - m) + vivco->len + 1;
if (len > sizeof(*dhcp))
goto toobig;
if (vivco->len + 2 + *lp > 255) {
logger(ifp->ctx, LOG_ERR,
"%s: VIVCO option too big",
ifp->name);
free(dhcp);
return -1;
}
*p++ = (uint8_t)vivco->len;
memcpy(p, vivco->data, vivco->len);
p += vivco->len;
*lp = (uint8_t)(*lp + vivco->len + 1);
}
}
len = (size_t)((p - m) + 3);
if (len > sizeof(*dhcp))
goto toobig;
*p++ = DHO_PARAMETERREQUESTLIST;
n_params = p;
*p++ = 0;
for (i = 0, opt = ifp->ctx->dhcp_opts;
i < ifp->ctx->dhcp_opts_len;
i++, opt++)
{
if (!(opt->type & REQUEST ||
has_option_mask(ifo->requestmask, opt->option)))
continue;
if (opt->type & NOREQ)
continue;
if (type == DHCP_INFORM &&
(opt->option == DHO_RENEWALTIME ||
opt->option == DHO_REBINDTIME))
continue;
len = (size_t)((p - m) + 2);
if (len > sizeof(*dhcp))
goto toobig;
*p++ = (uint8_t)opt->option;
}
for (i = 0, opt = ifo->dhcp_override;
i < ifo->dhcp_override_len;
i++, opt++)
{
/* Check if added above */
for (lp = n_params + 1; lp < p; lp++)
if (*lp == (uint8_t)opt->option)
break;
if (lp < p)
continue;
if (!(opt->type & REQUEST ||
has_option_mask(ifo->requestmask, opt->option)))
continue;
if (opt->type & NOREQ)
continue;
if (type == DHCP_INFORM &&
(opt->option == DHO_RENEWALTIME ||
opt->option == DHO_REBINDTIME))
continue;
len = (size_t)((p - m) + 2);
if (len > sizeof(*dhcp))
goto toobig;
*p++ = (uint8_t)opt->option;
}
*n_params = (uint8_t)(p - n_params - 1);
}
/* silence GCC */
auth_len = 0;
auth = NULL;
if (ifo->auth.options & DHCPCD_AUTH_SEND) {
ssize_t alen = dhcp_auth_encode(&ifo->auth,
state->auth.token,
NULL, 0, 4, type, NULL, 0);
if (alen != -1 && alen > UINT8_MAX) {
errno = ERANGE;
alen = -1;
}
if (alen == -1)
logger(ifp->ctx, LOG_ERR,
"%s: dhcp_auth_encode: %m", ifp->name);
else if (alen != 0) {
auth_len = (uint8_t)alen;
len = (size_t)((p + alen) - m);
if (len > sizeof(*dhcp))
goto toobig;
*p++ = DHO_AUTHENTICATION;
*p++ = auth_len;
auth = p;
p += auth_len;
}
}
*p++ = DHO_END;
/* Pad out to the BOOTP minimum message length.
* Some DHCP servers incorrectly require this. */
while (p - m < BOOTP_MESSAGE_LENTH_MIN)
*p++ = DHO_PAD;
len = (size_t)(p - m);
if (ifo->auth.options & DHCPCD_AUTH_SEND && auth_len != 0)
dhcp_auth_encode(&ifo->auth, state->auth.token,
m, len, 4, type, auth, auth_len);
*message = dhcp;
return (ssize_t)len;
toobig:
logger(ifp->ctx, LOG_ERR, "%s: DHCP messge too big", ifp->name);
free(dhcp);
return -1;
}
static ssize_t
write_lease(const struct interface *ifp, const struct dhcp_message *dhcp)
{
int fd;
size_t len;
ssize_t bytes;
const uint8_t *e, *p;
uint8_t l;
uint8_t o = 0;
const struct dhcp_state *state = D_CSTATE(ifp);
uint8_t write_buffer[sizeof(*dhcp) + sizeof(state->server_info) + 1];
uint8_t *w;
/* We don't write BOOTP leases */
if (IS_BOOTP(ifp, dhcp)) {
unlink(state->leasefile);
return 0;
}
logger(ifp->ctx, LOG_DEBUG, "%s: writing lease `%s'",
ifp->name, state->leasefile);
fd = open(state->leasefile, O_WRONLY | O_CREAT | O_TRUNC, 0600);
if (fd == -1)
return -1;
/* Only write as much as we need */
p = dhcp->options;
e = p + sizeof(dhcp->options);
len = sizeof(*dhcp);
while (p < e) {
o = *p;
if (o == DHO_END) {
len = (size_t)(p - (const uint8_t *)dhcp);
break;
}
p++;
if (o != DHO_PAD) {
l = *p++;
p += l;
}
}
memcpy(write_buffer, dhcp, len);
w = write_buffer + len;
/* Copy in server info if this is available. */
if (state->server_info.gw_hwlen != 0) {
*w++ = DHO_END;
memcpy(w, &state->server_info, sizeof(state->server_info));
len += sizeof(state->server_info) + 1;
}
bytes = write(fd, write_buffer, len);
close(fd);
return bytes;
}
static struct dhcp_message *
read_lease(struct interface *ifp)
{
int fd;
struct dhcp_message *dhcp;
struct dhcp_state *state = D_STATE(ifp);
uint8_t read_buffer[sizeof(*dhcp) + sizeof(state->server_info) + 1];
const uint8_t *options_startp =
read_buffer + offsetof(struct dhcp_message, options);
const uint8_t *options_endp = options_startp + sizeof(dhcp->options);
uint8_t option_len;
uint8_t option_type = 0;
ssize_t bytes;
const uint8_t *auth;
uint8_t type;
size_t auth_len;
memset(&state->server_info, 0, sizeof(state->server_info));
fd = open(state->leasefile, O_RDONLY);
if (fd == -1) {
if (errno != ENOENT)
logger(ifp->ctx, LOG_ERR, "%s: open `%s': %m",
ifp->name, state->leasefile);
return NULL;
}
logger(ifp->ctx, LOG_DEBUG, "%s: reading lease `%s'",
ifp->name, state->leasefile);
bytes = read(fd, read_buffer, sizeof(read_buffer));
close(fd);
/* Lease file should at minimum contain all fields before options. */
if (read_buffer + bytes < options_startp)
return NULL;
dhcp = calloc(1, sizeof(*dhcp));
if (dhcp == NULL) {
return NULL;
}
if (options_endp > read_buffer + bytes)
options_endp = read_buffer + bytes;
while (options_startp < options_endp) {
option_type = *options_startp++;
if (option_type == DHO_END)
break;
if (option_type != DHO_PAD) {
option_len = *options_startp++;
options_startp += option_len;
}
}
memcpy(dhcp, read_buffer, options_startp - read_buffer);
/* We may have found a BOOTP server */
if (get_option_uint8(ifp->ctx, &type, dhcp, DHO_MESSAGETYPE) == -1)
type = 0;
/* Authenticate the message */
auth = get_option(ifp->ctx, dhcp, DHO_AUTHENTICATION, &auth_len);
if (auth) {
if (dhcp_auth_validate(&state->auth, &ifp->options->auth,
(uint8_t *)dhcp, sizeof(*dhcp), 4, type,
auth, auth_len) == NULL)
{
logger(ifp->ctx, LOG_DEBUG,
"%s: dhcp_auth_validate: %m", ifp->name);
free(dhcp);
return NULL;
}
if (state->auth.token)
logger(ifp->ctx, LOG_DEBUG,
"%s: validated using 0x%08" PRIu32,
ifp->name, state->auth.token->secretid);
else
logger(ifp->ctx, LOG_DEBUG,
"%s: accepted reconfigure key", ifp->name);
}
/*
* DHCP server information is stored after the DHO_END character
* in the lease file. The first byte of the server information
* is the length of the gateway hardware address.
*/
options_endp = read_buffer + bytes;
if (options_startp >= options_endp ||
options_startp + sizeof(state->server_info) > options_endp)
return dhcp;
logger(ifp->ctx, LOG_DEBUG, "%s: found server info in lease '%s'",
ifp->name, state->leasefile);
memcpy(&state->server_info, options_startp, sizeof(state->server_info));
if (state->server_info.gw_hwlen != ifp->hwlen) {
logger(ifp->ctx, LOG_ERR, "%s: lease file %s has incompatible"
"MAC address length %d (expected %zd)",
ifp->name, state->leasefile,
state->server_info.gw_hwlen, ifp->hwlen);
memset(&state->server_info, 0, sizeof(state->server_info));
}
return dhcp;
}
static const struct dhcp_opt *
dhcp_getoverride(const struct if_options *ifo, unsigned int o)
{
size_t i;
const struct dhcp_opt *opt;
for (i = 0, opt = ifo->dhcp_override;
i < ifo->dhcp_override_len;
i++, opt++)
{
if (opt->option == o)
return opt;
}
return NULL;
}
static const uint8_t *
dhcp_getoption(struct dhcpcd_ctx *ctx,
size_t *os, unsigned int *code, size_t *len,
const uint8_t *od, size_t ol, struct dhcp_opt **oopt)
{
size_t i;
struct dhcp_opt *opt;
if (od) {
if (ol < 2) {
errno = EINVAL;
return NULL;
}
*os = 2; /* code + len */
*code = (unsigned int)*od++;
*len = (size_t)*od++;
if (*len > ol - *os) {
errno = EINVAL;
return NULL;
}
}
*oopt = NULL;
for (i = 0, opt = ctx->dhcp_opts; i < ctx->dhcp_opts_len; i++, opt++) {
if (opt->option == *code) {
*oopt = opt;
break;
}
}
return od;
}
ssize_t
dhcp_env(char **env, const char *prefix, const struct dhcp_message *dhcp,
const struct interface *ifp)
{
const struct if_options *ifo;
const uint8_t *p;
struct in_addr addr;
struct in_addr net;
struct in_addr brd;
struct dhcp_opt *opt, *vo;
size_t e, i, pl;
char **ep;
char cidr[4], safe[(BOOTFILE_LEN * 4) + 1];
uint8_t overl = 0;
uint32_t en;
e = 0;
ifo = ifp->options;
get_option_uint8(ifp->ctx, &overl, dhcp, DHO_OPTIONSOVERLOADED);
if (env == NULL) {
if (dhcp->yiaddr || dhcp->ciaddr)
e += 5;
if (*dhcp->bootfile && !(overl & 1))
e++;
if (*dhcp->servername && !(overl & 2))
e++;
for (i = 0, opt = ifp->ctx->dhcp_opts;
i < ifp->ctx->dhcp_opts_len;
i++, opt++)
{
if (has_option_mask(ifo->nomask, opt->option))
continue;
if (dhcp_getoverride(ifo, opt->option))
continue;
p = get_option(ifp->ctx, dhcp, opt->option, &pl);
if (!p)
continue;
e += dhcp_envoption(ifp->ctx, NULL, NULL, ifp->name,
opt, dhcp_getoption, p, pl);
}
for (i = 0, opt = ifo->dhcp_override;
i < ifo->dhcp_override_len;
i++, opt++)
{
if (has_option_mask(ifo->nomask, opt->option))
continue;
p = get_option(ifp->ctx, dhcp, opt->option, &pl);
if (!p)
continue;
e += dhcp_envoption(ifp->ctx, NULL, NULL, ifp->name,
opt, dhcp_getoption, p, pl);
}
return (ssize_t)e;
}
ep = env;
if (dhcp->yiaddr || dhcp->ciaddr) {
/* Set some useful variables that we derive from the DHCP
* message but are not necessarily in the options */
addr.s_addr = dhcp->yiaddr ? dhcp->yiaddr : dhcp->ciaddr;
setvar(ifp->ctx, &ep, prefix, "ip_address", inet_ntoa(addr));
if (get_option_addr(ifp->ctx, &net,
dhcp, DHO_SUBNETMASK) == -1) {
net.s_addr = ipv4_getnetmask(addr.s_addr);
setvar(ifp->ctx, &ep, prefix,
"subnet_mask", inet_ntoa(net));
}
snprintf(cidr, sizeof(cidr), "%d", inet_ntocidr(net));
setvar(ifp->ctx, &ep, prefix, "subnet_cidr", cidr);
if (get_option_addr(ifp->ctx, &brd,
dhcp, DHO_BROADCAST) == -1) {
brd.s_addr = addr.s_addr | ~net.s_addr;
setvar(ifp->ctx, &ep, prefix,
"broadcast_address", inet_ntoa(brd));
}
addr.s_addr = dhcp->yiaddr & net.s_addr;
setvar(ifp->ctx, &ep, prefix,
"network_number", inet_ntoa(addr));
}
if (*dhcp->bootfile && !(overl & 1)) {
print_string(safe, sizeof(safe), STRING,
dhcp->bootfile, sizeof(dhcp->bootfile));
setvar(ifp->ctx, &ep, prefix, "filename", safe);
}
if (*dhcp->servername && !(overl & 2)) {
print_string(safe, sizeof(safe), STRING | DOMAIN,
dhcp->servername, sizeof(dhcp->servername));
setvar(ifp->ctx, &ep, prefix, "server_name", safe);
}
/* Zero our indexes */
if (env) {
for (i = 0, opt = ifp->ctx->dhcp_opts;
i < ifp->ctx->dhcp_opts_len;
i++, opt++)
dhcp_zero_index(opt);
for (i = 0, opt = ifp->options->dhcp_override;
i < ifp->options->dhcp_override_len;
i++, opt++)
dhcp_zero_index(opt);
for (i = 0, opt = ifp->ctx->vivso;
i < ifp->ctx->vivso_len;
i++, opt++)
dhcp_zero_index(opt);
}
for (i = 0, opt = ifp->ctx->dhcp_opts;
i < ifp->ctx->dhcp_opts_len;
i++, opt++)
{
if (has_option_mask(ifo->nomask, opt->option))
continue;
if (dhcp_getoverride(ifo, opt->option))
continue;
if ((p = get_option(ifp->ctx, dhcp, opt->option, &pl))) {
ep += dhcp_envoption(ifp->ctx, ep, prefix, ifp->name,
opt, dhcp_getoption, p, pl);
if (opt->option == DHO_VIVSO &&
pl > (int)sizeof(uint32_t))
{
memcpy(&en, p, sizeof(en));
en = ntohl(en);
vo = vivso_find(en, ifp);
if (vo) {
/* Skip over en + total size */
p += sizeof(en) + 1;
pl -= sizeof(en) + 1;
ep += dhcp_envoption(ifp->ctx,
ep, prefix, ifp->name,
vo, dhcp_getoption, p, pl);
}
}
}
}
for (i = 0, opt = ifo->dhcp_override;
i < ifo->dhcp_override_len;
i++, opt++)
{
if (has_option_mask(ifo->nomask, opt->option))
continue;
if ((p = get_option(ifp->ctx, dhcp, opt->option, &pl)))
ep += dhcp_envoption(ifp->ctx, ep, prefix, ifp->name,
opt, dhcp_getoption, p, pl);
}
return ep - env;
}
static void
get_lease(struct dhcpcd_ctx *ctx,
struct dhcp_lease *lease, const struct dhcp_message *dhcp)
{
lease->cookie = dhcp->cookie;
/* BOOTP does not set yiaddr for replies when ciaddr is set. */
if (dhcp->yiaddr)
lease->addr.s_addr = dhcp->yiaddr;
else
lease->addr.s_addr = dhcp->ciaddr;
if (get_option_addr(ctx, &lease->net, dhcp, DHO_SUBNETMASK) == -1)
lease->net.s_addr = ipv4_getnetmask(lease->addr.s_addr);
if (get_option_addr(ctx, &lease->brd, dhcp, DHO_BROADCAST) == -1)
lease->brd.s_addr = lease->addr.s_addr | ~lease->net.s_addr;
if (get_option_uint32(ctx, &lease->leasetime, dhcp, DHO_LEASETIME) != 0)
lease->leasetime = ~0U; /* Default to infinite lease */
if (get_option_uint32(ctx, &lease->renewaltime,
dhcp, DHO_RENEWALTIME) != 0)
lease->renewaltime = 0;
if (get_option_uint32(ctx, &lease->rebindtime,
dhcp, DHO_REBINDTIME) != 0)
lease->rebindtime = 0;
if (get_option_addr(ctx, &lease->server, dhcp, DHO_SERVERID) != 0)
lease->server.s_addr = INADDR_ANY;
}
static const char *
get_dhcp_op(uint8_t type)
{
const struct dhcp_op *d;
for (d = dhcp_ops; d->name; d++)
if (d->value == type)
return d->name;
return NULL;
}
static void
dhcp_fallback(void *arg)
{
struct interface *iface;
iface = (struct interface *)arg;
dhcpcd_selectprofile(iface, iface->options->fallback);
dhcpcd_startinterface(iface);
}
uint32_t
dhcp_xid(const struct interface *ifp)
{
uint32_t xid;
if (ifp->options->options & DHCPCD_XID_HWADDR &&
ifp->hwlen >= sizeof(xid))
/* The lower bits are probably more unique on the network */
memcpy(&xid, (ifp->hwaddr + ifp->hwlen) - sizeof(xid),
sizeof(xid));
else
xid = arc4random();
return xid;
}
void
dhcp_close(struct interface *ifp)
{
struct dhcp_state *state = D_STATE(ifp);
if (state == NULL)
return;
if (state->raw_fd != -1) {
eloop_event_delete(ifp->ctx->eloop, state->raw_fd, 0);
close(state->raw_fd);
state->raw_fd = -1;
}
state->interval = 0;
}
static int
dhcp_openudp(struct interface *ifp)
{
int s;
struct sockaddr_in sin;
int n;
struct dhcp_state *state;
#ifdef SO_BINDTODEVICE
struct ifreq ifr;
char *p;
#endif
#ifdef SOCK_CLOEXEC
if ((s = socket(PF_INET, SOCK_DGRAM | SOCK_CLOEXEC, IPPROTO_UDP)) == -1)
return -1;
#else
if ((s = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP)) == -1)
return -1;
if ((n = fcntl(s, F_GETFD, 0)) == -1 ||
fcntl(s, F_SETFD, n | FD_CLOEXEC) == -1)
{
close(s);
return -1;
}
#endif
n = 1;
if (setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &n, sizeof(n)) == -1)
goto eexit;
#ifdef SO_BINDTODEVICE
if (ifp) {
memset(&ifr, 0, sizeof(ifr));
strlcpy(ifr.ifr_name, ifp->name, sizeof(ifr.ifr_name));
/* We can only bind to the real device */
p = strchr(ifr.ifr_name, ':');
if (p)
*p = '\0';
if (setsockopt(s, SOL_SOCKET, SO_BINDTODEVICE, &ifr,
sizeof(ifr)) == -1)
goto eexit;
}
#endif
memset(&sin, 0, sizeof(sin));
sin.sin_family = AF_INET;
sin.sin_port = htons(DHCP_CLIENT_PORT);
if (ifp) {
state = D_STATE(ifp);
sin.sin_addr.s_addr = state->addr.s_addr;
} else
state = NULL; /* appease gcc */
if (bind(s, (struct sockaddr *)&sin, sizeof(sin)) == -1)
goto eexit;
return s;
eexit:
close(s);
return -1;
}
static uint16_t
checksum(const void *data, unsigned int len)
{
const uint8_t *addr = data;
uint32_t sum = 0;
while (len > 1) {
sum += (uint32_t)(addr[0] * 256 + addr[1]);
addr += 2;
len -= 2;
}
if (len == 1)
sum += (uint32_t)(*addr * 256);
sum = (sum >> 16) + (sum & 0xffff);
sum += (sum >> 16);
return (uint16_t)~htons((uint16_t)sum);
}
static struct udp_dhcp_packet *
dhcp_makeudppacket(size_t *sz, const uint8_t *data, size_t length,
struct in_addr source, struct in_addr dest)
{
struct udp_dhcp_packet *udpp;
struct ip *ip;
struct udphdr *udp;
udpp = calloc(1, sizeof(*udpp));
if (udpp == NULL)
return NULL;
ip = &udpp->ip;
udp = &udpp->udp;
/* OK, this is important :)
* We copy the data to our packet and then create a small part of the
* ip structure and an invalid ip_len (basically udp length).
* We then fill the udp structure and put the checksum
* of the whole packet into the udp checksum.
* Finally we complete the ip structure and ip checksum.
* If we don't do the ordering like so then the udp checksum will be
* broken, so find another way of doing it! */
memcpy(&udpp->dhcp, data, length);
ip->ip_p = IPPROTO_UDP;
ip->ip_src.s_addr = source.s_addr;
if (dest.s_addr == 0)
ip->ip_dst.s_addr = INADDR_BROADCAST;
else
ip->ip_dst.s_addr = dest.s_addr;
udp->uh_sport = htons(DHCP_CLIENT_PORT);
udp->uh_dport = htons(DHCP_SERVER_PORT);
udp->uh_ulen = htons((uint16_t)(sizeof(*udp) + length));
ip->ip_len = udp->uh_ulen;
udp->uh_sum = checksum(udpp, sizeof(*udpp));
ip->ip_v = IPVERSION;
ip->ip_hl = sizeof(*ip) >> 2;
ip->ip_id = (uint16_t)arc4random_uniform(UINT16_MAX);
ip->ip_ttl = IPDEFTTL;
ip->ip_len = htons((uint16_t)(sizeof(*ip) + sizeof(*udp) + length));
ip->ip_sum = checksum(ip, sizeof(*ip));
*sz = sizeof(*ip) + sizeof(*udp) + length;
return udpp;
}
static void
send_message(struct interface *ifp, uint8_t type,
void (*callback)(void *))
{
struct dhcp_state *state = D_STATE(ifp);
struct if_options *ifo = ifp->options;
struct dhcp_message *dhcp;
struct udp_dhcp_packet *udp;
size_t len;
ssize_t r;
struct in_addr from, to;
in_addr_t a = INADDR_ANY;
struct timespec tv;
int s;
#ifdef IN_IFF_NOTUSEABLE
struct ipv4_addr *ia;
#endif
if (!callback)
logger(ifp->ctx, LOG_INFO, "%s: sending %s with xid 0x%x",
ifp->name,
ifo->options & DHCPCD_BOOTP ? "BOOTP" : get_dhcp_op(type),
state->xid);
else {
if (state->interval == 0)
state->interval = DHCP_BASE;
else {
state->interval *= 2;
if (state->interval > DHCP_MAX)
state->interval = DHCP_MAX;
}
tv.tv_sec = state->interval + DHCP_RAND_MIN;
tv.tv_nsec = (suseconds_t)arc4random_uniform(
(DHCP_RAND_MAX - DHCP_RAND_MIN) * NSEC_PER_SEC);
timespecnorm(&tv);
logger(ifp->ctx, LOG_INFO,
"%s: sending %s (xid 0x%x), next in %0.1f seconds",
ifp->name,
ifo->options & DHCPCD_BOOTP ? "BOOTP" : get_dhcp_op(type),
state->xid,
timespec_to_double(&tv));
}
if (dhcp_open(ifp) == -1)
return;
if (state->added && !(state->added & STATE_FAKE) &&
state->addr.s_addr != INADDR_ANY &&
state->new != NULL &&
#ifdef IN_IFF_NOTUSEABLE
((ia = ipv4_iffindaddr(ifp, &state->addr, NULL)) &&
!(ia->addr_flags & IN_IFF_NOTUSEABLE)) &&
#endif
(state->new->cookie == htonl(MAGIC_COOKIE) ||
ifp->options->options & DHCPCD_INFORM))
{
s = dhcp_openudp(ifp);
if (s == -1 && errno != EADDRINUSE)
logger(ifp->ctx, LOG_ERR,
"%s: dhcp_openudp: %m", ifp->name);
} else
s = -1;
/* If we couldn't open a UDP port for our IP address
* then we cannot renew.
* This could happen if our IP was pulled out from underneath us.
* Also, we should not unicast from a BOOTP lease. */
if (s == -1 ||
(!(ifo->options & DHCPCD_INFORM) &&
IS_BOOTP(ifp, state->new)))
{
a = state->addr.s_addr;
state->addr.s_addr = INADDR_ANY;
}
r = make_message(&dhcp, ifp, type);
if (r == -1)
goto fail;
len = (size_t)r;
if (a)
state->addr.s_addr = a;
from.s_addr = dhcp->ciaddr;
if (from.s_addr)
to.s_addr = state->lease.server.s_addr;
else
to.s_addr = INADDR_ANY;
if (to.s_addr && to.s_addr != INADDR_BROADCAST) {
struct sockaddr_in sin;
memset(&sin, 0, sizeof(sin));
sin.sin_family = AF_INET;
sin.sin_addr.s_addr = to.s_addr;
sin.sin_port = htons(DHCP_SERVER_PORT);
r = sendto(s, (uint8_t *)dhcp, len, 0,
(struct sockaddr *)&sin, sizeof(sin));
if (r == -1)
logger(ifp->ctx, LOG_ERR,
"%s: dhcp_sendpacket: %m", ifp->name);
} else {
size_t ulen;
r = 0;
udp = dhcp_makeudppacket(&ulen, (uint8_t *)dhcp, len, from, to);
if (udp == NULL) {
logger(ifp->ctx, LOG_ERR, "dhcp_makeudppacket: %m");
} else {
r = if_sendrawpacket(ifp, ETHERTYPE_IP,
(uint8_t *)udp, ulen, NULL);
free(udp);
}
/* If we failed to send a raw packet this normally means
* we don't have the ability to work beneath the IP layer
* for this interface.
* As such we remove it from consideration without actually
* stopping the interface. */
if (r == -1) {
logger(ifp->ctx, LOG_ERR,
"%s: if_sendrawpacket: %m", ifp->name);
switch(errno) {
case ENETDOWN:
case ENETRESET:
case ENETUNREACH:
break;
default:
if (!(ifp->ctx->options & DHCPCD_TEST))
dhcp_drop(ifp, "FAIL");
dhcp_free(ifp);
eloop_timeout_delete(ifp->ctx->eloop,
NULL, ifp);
callback = NULL;
}
}
}
free(dhcp);
fail:
if (s != -1)
close(s);
/* Even if we fail to send a packet we should continue as we are
* as our failure timeouts will change out codepath when needed. */
if (callback)
eloop_timeout_add_tv(ifp->ctx->eloop, &tv, callback, ifp);
}
static void
send_inform(void *arg)
{
send_message((struct interface *)arg, DHCP_INFORM, send_inform);
}
static void
send_discover(void *arg)
{
send_message((struct interface *)arg, DHCP_DISCOVER, send_discover);
}
static void
send_request(void *arg)
{
send_message((struct interface *)arg, DHCP_REQUEST, send_request);
}
static void
send_renew(void *arg)
{
send_message((struct interface *)arg, DHCP_REQUEST, send_renew);
}
static void
send_rebind(void *arg)
{
send_message((struct interface *)arg, DHCP_REQUEST, send_rebind);
}
void
dhcp_discover(void *arg)
{
struct interface *ifp = arg;
struct dhcp_state *state = D_STATE(ifp);
struct if_options *ifo = ifp->options;
rpc_signal_status("Discover");
state->state = DHS_DISCOVER;
state->xid = dhcp_xid(ifp);
state->nak_receive_count = 0;
state->failed_address_offer_count = 0;
eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp);
if (ifo->fallback)
eloop_timeout_add_sec(ifp->ctx->eloop,
ifo->reboot, dhcp_fallback, ifp);
else if (ifo->options & DHCPCD_IPV4LL &&
!IN_LINKLOCAL(htonl(state->addr.s_addr)))
eloop_timeout_add_sec(ifp->ctx->eloop,
ifo->reboot, ipv4ll_start, ifp);
if (ifo->options & DHCPCD_REQUEST)
logger(ifp->ctx, LOG_INFO,
"%s: soliciting a DHCP lease (requesting %s)",
ifp->name, inet_ntoa(ifo->req_addr));
else
logger(ifp->ctx, LOG_INFO,
"%s: soliciting a %s lease",
ifp->name, ifo->options & DHCPCD_BOOTP ? "BOOTP" : "DHCP");
send_discover(ifp);
}
static void
dhcp_request(void *arg)
{
struct interface *ifp = arg;
struct dhcp_state *state = D_STATE(ifp);
logger(ifp->ctx, LOG_INFO, "%s: requesting lease of %s",
ifp->name, inet_ntoa(state->lease.addr));
rpc_signal_status("Request");
state->state = DHS_REQUEST;
state->nak_receive_count = 0;
send_request(ifp);
}
static void
dhcp_expire(void *arg)
{
struct interface *ifp = arg;
struct dhcp_state *state = D_STATE(ifp);
logger(ifp->ctx, LOG_ERR, "%s: DHCP lease expired", ifp->name);
eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp);
dhcp_drop(ifp, "EXPIRE");
unlink(state->leasefile);
state->interval = 0;
dhcp_discover(ifp);
}
static void
dhcp_decline(struct interface *ifp)
{
send_message(ifp, DHCP_DECLINE, NULL);
}
static void
dhcp_renew(void *arg)
{
struct interface *ifp = arg;
struct dhcp_state *state = D_STATE(ifp);
struct dhcp_lease *lease = &state->lease;
rpc_signal_status("Renew");
logger(ifp->ctx, LOG_INFO, "%s: renewing lease of %s",
ifp->name, inet_ntoa(lease->addr));
logger(ifp->ctx, LOG_DEBUG, "%s: rebind in %"PRIu32" seconds,"
" expire in %"PRIu32" seconds",
ifp->name, lease->rebindtime - lease->renewaltime,
lease->leasetime - lease->renewaltime);
state->state = DHS_RENEW;
state->xid = dhcp_xid(ifp);
state->nak_receive_count = 0;
send_renew(ifp);
}
#ifndef IN_IFF_TENTATIVE
static void
dhcp_arp_announced(struct arp_state *astate)
{
arp_close(astate->iface);
}
#endif
static void
dhcp_rebind(void *arg)
{
struct interface *ifp = arg;
struct dhcp_state *state = D_STATE(ifp);
struct dhcp_lease *lease = &state->lease;
rpc_signal_status("Rebind");
logger(ifp->ctx, LOG_WARNING,
"%s: failed to renew DHCP, rebinding", ifp->name);
logger(ifp->ctx, LOG_DEBUG, "%s: expire in %"PRIu32" seconds",
ifp->name, lease->leasetime - lease->rebindtime);
state->state = DHS_REBIND;
eloop_timeout_delete(ifp->ctx->eloop, send_renew, ifp);
state->lease.server.s_addr = 0;
state->nak_receive_count = 0;
ifp->options->options &= ~(DHCPCD_CSR_WARNED |
DHCPCD_ROUTER_HOST_ROUTE_WARNED);
send_rebind(ifp);
}
static void
init_option_iterator(const struct dhcp_message *message,
struct dhcp_option_iterator *iterator)
{
iterator->message = message;
iterator->ptr = message->options;
iterator->end = iterator->ptr + sizeof(message->options);
iterator->extra_option_locations = 0;
iterator->extra_option_locations_set = 0;
}
static int
iterate_next_option(struct dhcp_option_iterator *iterator,
uint8_t *option, uint8_t *length, const uint8_t **value)
{
uint8_t option_code;
uint8_t option_len;
/* Process special DHO_PAD and DHO_END opcodes. */
while (iterator->ptr < iterator->end) {
if (*iterator->ptr == DHO_PAD) {
iterator->ptr++;
continue;
}
if (*iterator->ptr != DHO_END)
break;
if (iterator->extra_option_locations &
OPTION_OVERLOADED_BOOT_FILE) {
iterator->extra_option_locations &=
~OPTION_OVERLOADED_BOOT_FILE;
iterator->ptr = iterator->message->bootfile;
iterator->end = iterator->ptr +
sizeof(iterator->message->bootfile);
} else if (iterator->extra_option_locations &
OPTION_OVERLOADED_SERVER_NAME) {
iterator->extra_option_locations &=
~OPTION_OVERLOADED_SERVER_NAME;
iterator->ptr = iterator->message->servername;
iterator->end = iterator->ptr +
sizeof(iterator->message->servername);
} else
return 0;
}
if (iterator->ptr + 2 > iterator->end)
return 0;
option_code = *iterator->ptr++;
option_len = *iterator->ptr++;
if (iterator->ptr + option_len > iterator->end)
return 0;
if (option_code == DHO_OPTIONSOVERLOADED && option_len > 0 &&
!iterator->extra_option_locations_set) {
iterator->extra_option_locations = *iterator->ptr;
iterator->extra_option_locations_set = 1;
}
if (option)
*option = option_code;
if (length)
*length = option_len;
if (value)
*value = iterator->ptr;
iterator->ptr += option_len;
return 1;
}
static void
merge_option_values(const struct dhcp_message *src,
struct dhcp_message *dst, uint8_t *copy_options)
{
uint8_t supplied_options[OPTION_MASK_SIZE];
struct dhcp_option_iterator dst_iterator;
struct dhcp_option_iterator src_iterator;
uint8_t option;
const uint8_t *option_value;
uint8_t option_length;
uint8_t *out;
const uint8_t *out_end;
int added_options = 0;
/* Traverse the destination message for options already supplied. */
memset(&supplied_options, 0, sizeof(supplied_options));
init_option_iterator(dst, &dst_iterator);
while (iterate_next_option(&dst_iterator, &option, NULL, NULL)) {
add_option_mask(supplied_options, option);
}
/* We will start merging options at the end of the last block
* the iterator traversed to. The const cast below is safe since
* this points to data within the (non-const) dst message. */
out = (uint8_t *) dst_iterator.ptr;
out_end = dst_iterator.end;
init_option_iterator(src, &src_iterator);
while (iterate_next_option(&src_iterator, &option, &option_length,
&option_value)) {
if (has_option_mask(supplied_options, option) ||
!has_option_mask(copy_options, option))
continue;
/* We need space for this option, plus a trailing DHO_END. */
if (out + option_length + 3 > out_end) {
syslog(LOG_ERR,
"%s: unable to fit option %d (length %d)",
__func__, option, option_length);
continue;
}
*out++ = option;
*out++ = option_length;
memcpy(out, option_value, option_length);
out += option_length;
added_options++;
}
if (added_options) {
*out++ = DHO_END;
syslog(LOG_INFO, "carrying over %d options from original offer",
added_options);
}
}
void
dhcp_bind(struct interface *ifp, struct arp_state *astate)
{
struct dhcp_state *state = D_STATE(ifp);
struct if_options *ifo = ifp->options;
struct dhcp_lease *lease = &state->lease;
uint8_t ipv4ll = 0;
if (state->state == DHS_BOUND)
goto applyaddr;
state->reason = NULL;
free(state->old);
state->old = state->new;
state->new = state->offer;
state->offer = NULL;
get_lease(ifp->ctx, lease, state->new);
if (ifo->options & DHCPCD_STATIC) {
logger(ifp->ctx, LOG_INFO, "%s: using static address %s/%d",
ifp->name, inet_ntoa(lease->addr),
inet_ntocidr(lease->net));
lease->leasetime = ~0U;
state->reason = "STATIC";
} else if (state->new->cookie != htonl(MAGIC_COOKIE)) {
logger(ifp->ctx, LOG_INFO, "%s: using IPv4LL address %s",
ifp->name, inet_ntoa(lease->addr));
lease->leasetime = ~0U;
state->reason = "IPV4LL";
ipv4ll = 1;
} else if (ifo->options & DHCPCD_INFORM) {
if (ifo->req_addr.s_addr != 0)
lease->addr.s_addr = ifo->req_addr.s_addr;
else
lease->addr.s_addr = state->addr.s_addr;
logger(ifp->ctx, LOG_INFO, "%s: received approval for %s",
ifp->name, inet_ntoa(lease->addr));
lease->leasetime = ~0U;
state->reason = "INFORM";
} else {
if (lease->frominfo)
state->reason = "TIMEOUT";
if (lease->leasetime == ~0U) {
lease->renewaltime =
lease->rebindtime =
lease->leasetime;
logger(ifp->ctx, LOG_INFO, "%s: leased %s for infinity",
ifp->name, inet_ntoa(lease->addr));
} else {
if (lease->leasetime < DHCP_MIN_LEASE) {
logger(ifp->ctx, LOG_WARNING,
"%s: minimum lease is %d seconds",
ifp->name, DHCP_MIN_LEASE);
lease->leasetime = DHCP_MIN_LEASE;
}
if (lease->rebindtime == 0)
lease->rebindtime =
(uint32_t)(lease->leasetime * T2);
else if (lease->rebindtime >= lease->leasetime) {
lease->rebindtime =
(uint32_t)(lease->leasetime * T2);
logger(ifp->ctx, LOG_WARNING,
"%s: rebind time greater than lease "
"time, forcing to %"PRIu32" seconds",
ifp->name, lease->rebindtime);
}
if (lease->renewaltime == 0)
lease->renewaltime =
(uint32_t)(lease->leasetime * T1);
else if (lease->renewaltime > lease->rebindtime) {
lease->renewaltime =
(uint32_t)(lease->leasetime * T1);
logger(ifp->ctx, LOG_WARNING,
"%s: renewal time greater than rebind "
"time, forcing to %"PRIu32" seconds",
ifp->name, lease->renewaltime);
}
logger(ifp->ctx,
lease->addr.s_addr == state->addr.s_addr &&
!(state->added & STATE_FAKE) ?
LOG_DEBUG : LOG_INFO,
"%s: leased %s for %"PRIu32" seconds", ifp->name,
inet_ntoa(lease->addr), lease->leasetime);
}
}
if (ifp->ctx->options & DHCPCD_TEST) {
state->reason = "TEST";
script_runreason(ifp, state->reason);
eloop_exit(ifp->ctx->eloop, EXIT_SUCCESS);
return;
}
if (state->reason == NULL) {
if (state->old && !(state->added & STATE_FAKE)) {
if (state->old->yiaddr == state->new->yiaddr &&
lease->server.s_addr)
state->reason = "RENEW";
else
state->reason = "REBIND";
} else if (state->state == DHS_REBOOT)
state->reason = "REBOOT";
else
state->reason = "BOUND";
}
if (state->old && state->old->yiaddr == state->new->yiaddr &&
(state->state == DHS_REBOOT || state->state == DHS_RENEW ||
state->state == DHS_REBIND)) {
/* Some DHCP servers respond to REQUEST with a subset
* of the original requested parameters. If they were not
* supplied in the response to a renewal, we should assume
* that it's reasonable to transfer them forward from the
* original offer. */
merge_option_values(state->old, state->new, ifo->requestmask);
}
if (lease->leasetime == ~0U)
lease->renewaltime = lease->rebindtime = lease->leasetime;
else {
eloop_timeout_add_sec(ifp->ctx->eloop,
(time_t)lease->renewaltime, dhcp_renew, ifp);
eloop_timeout_add_sec(ifp->ctx->eloop,
(time_t)lease->rebindtime, dhcp_rebind, ifp);
eloop_timeout_add_sec(ifp->ctx->eloop,
(time_t)lease->leasetime, dhcp_expire, ifp);
logger(ifp->ctx, LOG_DEBUG,
"%s: renew in %"PRIu32" seconds, rebind in %"PRIu32
" seconds",
ifp->name, lease->renewaltime, lease->rebindtime);
}
if (!(ifo->options & DHCPCD_STATIC) &&
state->new->cookie != htonl(MAGIC_COOKIE))
state->state = DHS_IPV4LL_BOUND;
else
state->state = DHS_BOUND;
if (!state->lease.frominfo &&
!(ifo->options & (DHCPCD_INFORM | DHCPCD_STATIC)))
if (write_lease(ifp, state->new) == -1)
logger(ifp->ctx, LOG_ERR,
"%s: write_lease: %m", __func__);
applyaddr:
ipv4_applyaddr(ifp);
if (ifo->options & DHCPCD_ARP &&
!(ifp->ctx->options & DHCPCD_FORKED))
{
#ifdef IN_IFF_TENTATIVE
if (astate)
arp_free_but(astate);
else if (!ipv4ll)
arp_close(ifp);
#else
if (state->added) {
if (astate == NULL) {
astate = arp_new(ifp, &state->addr);
astate->announced_cb =
dhcp_arp_announced;
}
if (astate) {
arp_announce(astate);
if (!ipv4ll)
arp_free_but(astate);
}
} else if (!ipv4ll)
arp_close(ifp);
#endif
}
}
static void
dhcp_timeout(void *arg)
{
struct interface *ifp = arg;
struct dhcp_state *state = D_STATE(ifp);
dhcp_bind(ifp, NULL);
state->interval = 0;
dhcp_discover(ifp);
}
struct dhcp_message *
dhcp_message_new(const struct in_addr *addr, const struct in_addr *mask)
{
struct dhcp_message *dhcp;
uint8_t *p;
dhcp = calloc(1, sizeof(*dhcp));
if (dhcp == NULL)
return NULL;
dhcp->yiaddr = addr->s_addr;
p = dhcp->options;
if (mask && mask->s_addr != INADDR_ANY) {
*p++ = DHO_SUBNETMASK;
*p++ = sizeof(mask->s_addr);
memcpy(p, &mask->s_addr, sizeof(mask->s_addr));
p+= sizeof(mask->s_addr);
}
*p++ = DHO_END;
return dhcp;
}
static void
dhcp_static(struct interface *ifp)
{
struct if_options *ifo;
struct dhcp_state *state;
state = D_STATE(ifp);
ifo = ifp->options;
if (ifo->req_addr.s_addr == INADDR_ANY) {
logger(ifp->ctx, LOG_INFO,
"%s: waiting for 3rd party to "
"configure IP address",
ifp->name);
state->reason = "3RDPARTY";
script_runreason(ifp, state->reason);
return;
}
state->offer = dhcp_message_new(&ifo->req_addr, &ifo->req_mask);
if (state->offer) {
eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp);
dhcp_bind(ifp, NULL);
}
}
void
dhcp_inform(struct interface *ifp)
{
struct dhcp_state *state;
struct if_options *ifo;
struct ipv4_addr *ap;
state = D_STATE(ifp);
ifo = ifp->options;
logger(ifp->ctx, LOG_INFO, "%s: informing peers of local address",
ifp->name);
if (ifp->ctx->options & DHCPCD_TEST) {
state->addr.s_addr = ifo->req_addr.s_addr;
state->net.s_addr = ifo->req_mask.s_addr;
} else {
if (ifo->req_addr.s_addr == INADDR_ANY) {
state = D_STATE(ifp);
ap = ipv4_iffindaddr(ifp, NULL, NULL);
if (ap == NULL) {
logger(ifp->ctx, LOG_INFO,
"%s: waiting for 3rd party to "
"configure IP address",
ifp->name);
state->reason = "3RDPARTY";
script_runreason(ifp, state->reason);
return;
}
state->offer =
dhcp_message_new(&ap->addr, &ap->net);
} else
state->offer =
dhcp_message_new(&ifo->req_addr, &ifo->req_mask);
if (state->offer) {
ifo->options |= DHCPCD_STATIC;
dhcp_bind(ifp, NULL);
ifo->options &= ~DHCPCD_STATIC;
}
}
rpc_signal_status("Inform");
state->state = DHS_INFORM;
state->xid = dhcp_xid(ifp);
send_inform(ifp);
}
void
dhcp_reboot_newopts(struct interface *ifp, unsigned long long oldopts)
{
struct if_options *ifo;
struct dhcp_state *state = D_STATE(ifp);
if (state == NULL)
return;
ifo = ifp->options;
if ((ifo->options & (DHCPCD_INFORM | DHCPCD_STATIC) &&
state->addr.s_addr != ifo->req_addr.s_addr) ||
(oldopts & (DHCPCD_INFORM | DHCPCD_STATIC) &&
!(ifo->options & (DHCPCD_INFORM | DHCPCD_STATIC))))
{
dhcp_drop(ifp, "EXPIRE");
}
}
static void start_unicast_arp(struct interface *ifp);
static void
dhcp_reboot(struct interface *ifp)
{
struct if_options *ifo;
struct dhcp_state *state = D_STATE(ifp);
if (state == NULL)
return;
rpc_signal_status("Reboot");
ifo = ifp->options;
state->state = DHS_REBOOT;
state->interval = 0;
if (ifo->options & DHCPCD_LINK && ifp->carrier == LINK_DOWN) {
logger(ifp->ctx, LOG_INFO,
"%s: waiting for carrier", ifp->name);
return;
}
if (ifo->options & DHCPCD_STATIC) {
dhcp_static(ifp);
return;
}
if (ifo->options & DHCPCD_UNICAST_ARP) {
start_unicast_arp(ifp);
}
if (ifo->options & DHCPCD_INFORM) {
logger(ifp->ctx, LOG_INFO, "%s: informing address of %s",
ifp->name, inet_ntoa(state->lease.addr));
dhcp_inform(ifp);
return;
}
if (ifo->reboot == 0 || state->offer == NULL) {
dhcp_discover(ifp);
return;
}
if (state->offer->cookie == 0)
return;
logger(ifp->ctx, LOG_INFO, "%s: rebinding lease of %s",
ifp->name, inet_ntoa(state->lease.addr));
state->xid = dhcp_xid(ifp);
state->lease.server.s_addr = 0;
eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp);
/* Need to add this before dhcp_expire and friends. */
if (!ifo->fallback && ifo->options & DHCPCD_IPV4LL &&
!IN_LINKLOCAL(htonl(state->addr.s_addr)))
eloop_timeout_add_sec(ifp->ctx->eloop,
ifo->reboot, ipv4ll_start, ifp);
if (ifo->options & DHCPCD_LASTLEASE && state->lease.frominfo)
eloop_timeout_add_sec(ifp->ctx->eloop,
ifo->reboot, dhcp_timeout, ifp);
else if (!(ifo->options & DHCPCD_INFORM))
eloop_timeout_add_sec(ifp->ctx->eloop,
ifo->reboot, dhcp_expire, ifp);
/* Don't bother ARP checking as the server could NAK us first.
* Don't call dhcp_request as that would change the state */
send_request(ifp);
}
void
dhcp_drop(struct interface *ifp, const char *reason)
{
struct dhcp_state *state;
#ifdef RELEASE_SLOW
struct timespec ts;
#endif
state = D_STATE(ifp);
/* dhcp_start may just have been called and we don't yet have a state
* but we do have a timeout, so punt it. */
if (state == NULL) {
eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp);
return;
}
/* Don't reset DHCP state if we have an IPv4LL address and link is up,
* unless the interface is departing. */
if (state->state != DHS_IPV4LL_BOUND ||
ifp->carrier != LINK_UP ||
ifp->options->options & DHCPCD_DEPARTED)
{
eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp);
dhcp_auth_reset(&state->auth);
dhcp_close(ifp);
}
if (ifp->options->options & DHCPCD_RELEASE ||
strcmp(reason, "RELEASE") == 0) {
unlink(state->leasefile);
if (ifp->carrier != LINK_DOWN &&
state->new != NULL &&
state->new->cookie == htonl(MAGIC_COOKIE))
{
logger(ifp->ctx, LOG_INFO, "%s: releasing lease of %s",
ifp->name, inet_ntoa(state->lease.addr));
state->xid = dhcp_xid(ifp);
send_message(ifp, DHCP_RELEASE, NULL);
#ifdef RELEASE_SLOW
/* Give the packet a chance to go */
ts.tv_sec = RELEASE_DELAY_S;
ts.tv_nsec = RELEASE_DELAY_NS;
nanosleep(&ts, NULL);
#endif
}
}
free(state->old);
state->old = state->new;
state->new = NULL;
state->reason = reason;
ipv4_applyaddr(ifp);
free(state->old);
state->old = NULL;
state->lease.addr.s_addr = 0;
ifp->options->options &= ~(DHCPCD_CSR_WARNED |
DHCPCD_ROUTER_HOST_ROUTE_WARNED);
}
static void
log_dhcp1(int lvl, const char *msg,
const struct interface *ifp, const struct dhcp_message *dhcp,
const struct in_addr *from, int ad)
{
const char *tfrom;
char *a, sname[sizeof(dhcp->servername) * 4];
struct in_addr addr;
int r;
if (strcmp(msg, "NAK:") == 0) {
a = get_option_string(ifp->ctx, dhcp, DHO_MESSAGE);
if (a) {
char *tmp;
size_t al, tmpl;
al = strlen(a);
tmpl = (al * 4) + 1;
tmp = malloc(tmpl);
if (tmp == NULL) {
logger(ifp->ctx, LOG_ERR, "%s: %m", __func__);
free(a);
return;
}
print_string(tmp, tmpl, STRING, (uint8_t *)a, al);
free(a);
a = tmp;
}
} else if (ad && dhcp->yiaddr != 0) {
addr.s_addr = dhcp->yiaddr;
a = strdup(inet_ntoa(addr));
if (a == NULL) {
logger(ifp->ctx, LOG_ERR, "%s: %m", __func__);
return;
}
} else
a = NULL;
tfrom = "from";
r = get_option_addr(ifp->ctx, &addr, dhcp, DHO_SERVERID);
if (dhcp->servername[0] && r == 0) {
print_string(sname, sizeof(sname), STRING,
dhcp->servername, strlen((const char *)dhcp->servername));
if (a == NULL)
logger(ifp->ctx, lvl, "%s: %s %s %s `%s'",
ifp->name, msg, tfrom, inet_ntoa(addr), sname);
else
logger(ifp->ctx, lvl, "%s: %s %s %s %s `%s'",
ifp->name, msg, a, tfrom, inet_ntoa(addr), sname);
} else {
if (r != 0) {
tfrom = "via";
addr = *from;
}
if (a == NULL)
logger(ifp->ctx, lvl, "%s: %s %s %s",
ifp->name, msg, tfrom, inet_ntoa(addr));
else
logger(ifp->ctx, lvl, "%s: %s %s %s %s",
ifp->name, msg, a, tfrom, inet_ntoa(addr));
}
free(a);
}
static void
log_dhcp(int lvl, const char *msg,
const struct interface *ifp, const struct dhcp_message *dhcp,
const struct in_addr *from)
{
log_dhcp1(lvl, msg, ifp, dhcp, from, 1);
}
static int
blacklisted_ip(const struct if_options *ifo, in_addr_t addr)
{
size_t i;
for (i = 0; i < ifo->blacklist_len; i += 2)
if (ifo->blacklist[i] == (addr & ifo->blacklist[i + 1]))
return 1;
return 0;
}
static int
whitelisted_ip(const struct if_options *ifo, in_addr_t addr)
{
size_t i;
if (ifo->whitelist_len == 0)
return -1;
for (i = 0; i < ifo->whitelist_len; i += 2)
if (ifo->whitelist[i] == (addr & ifo->whitelist[i + 1]))
return 1;
return 0;
}
static void
save_gateway_addr(struct interface *ifp, const uint8_t *gw_hwaddr)
{
struct dhcp_state *state = D_STATE(ifp);
memcpy(state->server_info.gw_hwaddr, gw_hwaddr, ifp->hwlen);
state->server_info.gw_hwlen = ifp->hwlen;
}
static void
dhcp_probe_gw_timeout(struct arp_state *astate)
{
struct dhcp_state *state = D_STATE(astate->iface);
/* Ignore unicast ARP failures. */
if (astate->dest_hwlen)
return;
/* Probegw failure, allow ourselves to fail only once this way */
logger(astate->iface->ctx, LOG_ERR,
"%s: Probe gateway %s timed out ",
astate->iface->name, inet_ntoa(astate->addr));
astate->iface->options->options &= ~DHCPCD_ARPGW;
unlink(state->leasefile);
if (!state->lease.frominfo)
dhcp_decline(astate->iface);
#ifdef IN_IFF_DUPLICATED
ia = ipv4_iffindaddr(astate->iface, &astate->addr, NULL);
if (ia)
ipv4_deladdr(astate->iface, &ia->addr, &ia->net);
#endif
eloop_timeout_delete(astate->iface->ctx->eloop, NULL,
astate->iface);
eloop_timeout_add_sec(astate->iface->ctx->eloop,
DHCP_RAND_MAX, dhcp_discover, astate->iface);
}
static void
dhcp_probe_gw_response(struct arp_state *astate, const struct arp_msg *amsg)
{
/* Verify this is a response for the gateway probe. */
if (astate->src_addr.s_addr != 0 &&
amsg &&
amsg->tip.s_addr == astate->src_addr.s_addr &&
amsg->sip.s_addr == astate->addr.s_addr) {
if (astate->dest_hwlen) {
/* Response to unicast ARP. */
rpc_notify_unicast_arp(astate->iface);
} else {
/* Response to arpgw request. */
save_gateway_addr(astate->iface, amsg->sha);
dhcp_close(astate->iface);
eloop_timeout_delete(astate->iface->ctx->eloop,
NULL, astate->iface);
#ifdef IN_IFF_TENTATIVE
ipv4_finaliseaddr(astate->iface);
#else
dhcp_bind(astate->iface, NULL);
#endif
}
arp_close(astate->iface);
}
}
static int
dhcp_probe_gw(struct interface *ifp)
{
struct dhcp_state *state = D_STATE(ifp);
struct arp_state *astate;
struct in_addr gateway_addr;
if (get_option_addr(ifp->ctx, &gateway_addr,
state->offer, DHO_ROUTER) == 0) {
astate = arp_new(ifp, &gateway_addr);
if (astate) {
astate->src_addr.s_addr = state->offer->yiaddr;
astate->probed_cb = dhcp_probe_gw_timeout;
astate->conflicted_cb = dhcp_probe_gw_response;
arp_probe(astate);
return 1;
}
}
return 0;
}
static void
start_unicast_arp(struct interface *ifp)
{
struct dhcp_state *state = D_STATE(ifp);
struct in_addr gwa;
struct in_addr src_addr;
struct arp_state *astate;
if (!state->offer)
return;
if (!state->lease.frominfo)
return;
if (state->server_info.gw_hwlen != ifp->hwlen)
return;
if (get_option_addr(ifp->ctx, &gwa, state->offer, DHO_ROUTER))
return;
astate = arp_new(ifp, &gwa);
if (!astate)
return;
if (state->offer->yiaddr)
astate->src_addr.s_addr = state->offer->yiaddr;
else
astate->src_addr.s_addr = state->offer->ciaddr;
astate->probed_cb = dhcp_probe_gw_timeout;
astate->conflicted_cb = dhcp_probe_gw_response;
astate->dest_hwlen = state->server_info.gw_hwlen;
memcpy(astate->dest_hwaddr, state->server_info.gw_hwaddr,
state->server_info.gw_hwlen);
arp_probe(astate);
/* Invalidate our gateway address until the next successful PROBEGW. */
state->server_info.gw_hwlen = 0;
}
static void
dhcp_arp_probed(struct arp_state *astate)
{
struct dhcp_state *state;
struct if_options *ifo;
/* We didn't find a profile for this
* address or hwaddr, so move to the next
* arping profile */
state = D_STATE(astate->iface);
ifo = astate->iface->options;
if (state->arping_index < ifo->arping_len) {
if (++state->arping_index < ifo->arping_len) {
astate->addr.s_addr =
ifo->arping[state->arping_index - 1];
arp_probe(astate);
}
dhcpcd_startinterface(astate->iface);
return;
}
/* Probe the gateway specified in the lease offer. */
if ((ifo->options & DHCPCD_ARPGW) && (dhcp_probe_gw(astate->iface))) {
return;
}
dhcp_close(astate->iface);
eloop_timeout_delete(astate->iface->ctx->eloop, NULL, astate->iface);
#ifdef IN_IFF_TENTATIVE
ipv4_finaliseaddr(astate->iface);
arp_close(astate->iface);
#else
dhcp_bind(astate->iface, astate);
#endif
}
static void
dhcp_arp_conflicted(struct arp_state *astate, const struct arp_msg *amsg)
{
struct dhcp_state *state;
struct if_options *ifo;
state = D_STATE(astate->iface);
ifo = astate->iface->options;
if (state->arping_index &&
state->arping_index <= ifo->arping_len &&
amsg &&
(amsg->sip.s_addr == ifo->arping[state->arping_index - 1] ||
(amsg->sip.s_addr == 0 &&
amsg->tip.s_addr == ifo->arping[state->arping_index - 1])))
{
char buf[HWADDR_LEN * 3];
astate->failed.s_addr = ifo->arping[state->arping_index - 1];
arp_report_conflicted(astate, amsg);
hwaddr_ntoa(amsg->sha, astate->iface->hwlen, buf, sizeof(buf));
if (dhcpcd_selectprofile(astate->iface, buf) == -1 &&
dhcpcd_selectprofile(astate->iface,
inet_ntoa(astate->failed)) == -1)
{
/* We didn't find a profile for this
* address or hwaddr, so move to the next
* arping profile */
dhcp_arp_probed(astate);
return;
}
dhcp_close(astate->iface);
arp_close(astate->iface);
eloop_timeout_delete(astate->iface->ctx->eloop, NULL,
astate->iface);
dhcpcd_startinterface(astate->iface);
}
/* RFC 2131 3.1.5, Client-server interaction
* NULL amsg means IN_IFF_DUPLICATED */
if (amsg == NULL || (state->offer &&
(amsg->sip.s_addr == state->offer->yiaddr ||
(amsg->sip.s_addr == 0 &&
amsg->tip.s_addr == state->offer->yiaddr))))
{
#ifdef IN_IFF_DUPLICATED
struct ipv4_addr *ia;
#endif
if (amsg) {
astate->failed.s_addr = state->offer->yiaddr;
state->failed.s_addr = state->offer->yiaddr;
} else {
astate->failed = astate->addr;
state->failed = astate->addr;
}
arp_report_conflicted(astate, amsg);
unlink(state->leasefile);
if (!state->lease.frominfo)
dhcp_decline(astate->iface);
#ifdef IN_IFF_DUPLICATED
ia = ipv4_iffindaddr(astate->iface, &astate->addr, NULL);
if (ia)
ipv4_deladdr(astate->iface, &ia->addr, &ia->net);
#endif
arp_close(astate->iface);
eloop_timeout_delete(astate->iface->ctx->eloop, NULL,
astate->iface);
eloop_timeout_add_sec(astate->iface->ctx->eloop,
DHCP_RAND_MAX, dhcp_discover, astate->iface);
}
}
static void
handle_nak(void *arg)
{
struct interface *ifp = arg;
struct dhcp_state *state = D_STATE(ifp);
logger(ifp->ctx, LOG_INFO, "%s: Handling deferred NAK", ifp->name);
if (!(ifp->ctx->options & DHCPCD_TEST)) {
dhcp_drop(ifp, "NAK");
unlink(state->leasefile);
}
/* If we constantly get NAKS then we should slowly back off */
eloop_timeout_add_sec(ifp->ctx->eloop,
state->nakoff, dhcp_discover, ifp);
if (state->nakoff == 0)
state->nakoff = 1;
else {
state->nakoff *= 2;
if (state->nakoff > NAKOFF_MAX)
state->nakoff = NAKOFF_MAX;
}
}
static void
dhcp_handledhcp(struct interface *ifp, struct dhcp_message **dhcpp,
const struct in_addr *from)
{
struct dhcp_state *state = D_STATE(ifp);
struct if_options *ifo = ifp->options;
struct dhcp_message *dhcp = *dhcpp;
struct dhcp_lease *lease = &state->lease;
uint8_t type, tmp;
const uint8_t *auth;
struct in_addr addr;
unsigned int i;
size_t auth_len;
char *msg;
struct arp_state *astate;
struct ipv4_addr *ia;
/* We may have found a BOOTP server */
if (get_option_uint8(ifp->ctx, &type, dhcp, DHO_MESSAGETYPE) == -1)
type = 0;
else if (ifo->options & DHCPCD_BOOTP) {
logger(ifp->ctx, LOG_DEBUG,
"%s: ignoring DHCP reply (excpecting BOOTP)",
ifp->name);
return;
}
logger(ifp->ctx, LOG_INFO, "%s: received %s with xid 0x%x",
ifp->name, get_dhcp_op(type), state->xid);
/* Authenticate the message */
auth = get_option(ifp->ctx, dhcp, DHO_AUTHENTICATION, &auth_len);
if (auth) {
if (dhcp_auth_validate(&state->auth, &ifo->auth,
(uint8_t *)*dhcpp, sizeof(**dhcpp), 4, type,
auth, auth_len) == NULL)
{
logger(ifp->ctx, LOG_DEBUG,
"%s: dhcp_auth_validate: %m", ifp->name);
log_dhcp1(LOG_ERR, "authentication failed",
ifp, dhcp, from, 0);
return;
}
if (state->auth.token)
logger(ifp->ctx, LOG_DEBUG,
"%s: validated using 0x%08" PRIu32,
ifp->name, state->auth.token->secretid);
else
logger(ifp->ctx, LOG_DEBUG,
"%s: accepted reconfigure key", ifp->name);
} else if (ifo->auth.options & DHCPCD_AUTH_REQUIRE) {
log_dhcp1(LOG_ERR, "no authentication", ifp, dhcp, from, 0);
return;
} else if (ifo->auth.options & DHCPCD_AUTH_SEND)
log_dhcp1(LOG_WARNING, "no authentication",
ifp, dhcp, from, 0);
/* RFC 3203 */
if (type == DHCP_FORCERENEW) {
if (from->s_addr == INADDR_ANY ||
from->s_addr == INADDR_BROADCAST)
{
log_dhcp(LOG_ERR, "discarding Force Renew",
ifp, dhcp, from);
return;
}
if (auth == NULL) {
log_dhcp(LOG_ERR, "unauthenticated Force Renew",
ifp, dhcp, from);
return;
}
if (state->state != DHS_BOUND && state->state != DHS_INFORM) {
log_dhcp(LOG_DEBUG, "not bound, ignoring Force Renew",
ifp, dhcp, from);
return;
}
log_dhcp(LOG_ERR, "Force Renew from", ifp, dhcp, from);
/* The rebind and expire timings are still the same, we just
* enter the renew state early */
if (state->state == DHS_BOUND) {
eloop_timeout_delete(ifp->ctx->eloop,
dhcp_renew, ifp);
dhcp_renew(ifp);
} else {
eloop_timeout_delete(ifp->ctx->eloop,
send_inform, ifp);
dhcp_inform(ifp);
}
return;
}
if (state->state == DHS_BOUND) {
/* Before we supported FORCERENEW we closed off the raw
* port so we effectively ignored all messages.
* As such we'll not log by default here. */
//log_dhcp(LOG_DEBUG, "bound, ignoring", iface, dhcp, from);
return;
}
/* Ensure it's the right transaction */
if (state->xid != ntohl(dhcp->xid)) {
logger(ifp->ctx, LOG_DEBUG,
"%s: wrong xid 0x%x (expecting 0x%x) from %s",
ifp->name, ntohl(dhcp->xid), state->xid,
inet_ntoa(*from));
return;
}
/* reset the message counter */
state->interval = 0;
/* Ensure that no reject options are present */
for (i = 1; i < 255; i++) {
if (has_option_mask(ifo->rejectmask, i) &&
get_option_uint8(ifp->ctx, &tmp, dhcp, (uint8_t)i) == 0)
{
log_dhcp(LOG_WARNING, "reject DHCP", ifp, dhcp, from);
return;
}
}
if (type == DHCP_NAK) {
if ((msg = get_option_string(ifp->ctx, dhcp, DHO_MESSAGE))) {
logger(ifp->ctx, LOG_WARNING, "%s: message: %s",
ifp->name, msg);
free(msg);
}
if (state->state == DHS_INFORM) /* INFORM should not be NAKed */
return;
log_dhcp(LOG_WARNING, "NAK (deferred):", ifp, dhcp, from);
rpc_signal_status("NakDefer");
if (state->nak_receive_count == 0)
eloop_timeout_add_sec(ifp->ctx->eloop,
DHCP_BASE, handle_nak, ifp);
state->nak_receive_count++;
return;
}
/* Ensure that all required options are present */
for (i = 1; i < 255; i++) {
if (has_option_mask(ifo->requiremask, i) &&
get_option_uint8(ifp->ctx, &tmp, dhcp, (uint8_t)i) != 0)
{
/* If we are BOOTP, then ignore the need for serverid.
* To ignore BOOTP, require dhcp_message_type.
* However, nothing really stops BOOTP from providing
* DHCP style options as well so the above isn't
* always true. */
if (type == 0 && i == DHO_SERVERID)
continue;
log_dhcp(LOG_WARNING, "reject DHCP", ifp, dhcp, from);
return;
}
}
/* DHCP Auto-Configure, RFC 2563 */
if (type == DHCP_OFFER && dhcp->yiaddr == 0) {
log_dhcp(LOG_WARNING, "no address given", ifp, dhcp, from);
if ((msg = get_option_string(ifp->ctx, dhcp, DHO_MESSAGE))) {
logger(ifp->ctx, LOG_WARNING,
"%s: message: %s", ifp->name, msg);
free(msg);
}
if ((state->state == DHS_DISCOVER ||
state->state == DHS_IPV4LL_BOUND) &&
get_option_uint8(ifp->ctx, &tmp, dhcp,
DHO_AUTOCONFIGURE) == 0)
{
switch (tmp) {
case 0:
log_dhcp(LOG_WARNING, "IPv4LL disabled from",
ifp, dhcp, from);
dhcp_drop(ifp, "EXPIRE");
arp_close(ifp);
eloop_timeout_delete(ifp->ctx->eloop,
NULL, ifp);
eloop_timeout_add_sec(ifp->ctx->eloop,
DHCP_MAX, dhcp_discover,
ifp);
break;
case 1:
log_dhcp(LOG_WARNING, "IPv4LL enabled from",
ifp, dhcp, from);
eloop_timeout_delete(ifp->ctx->eloop,
NULL, ifp);
if (IN_LINKLOCAL(htonl(state->addr.s_addr)))
eloop_timeout_add_sec(ifp->ctx->eloop,
DHCP_MAX, dhcp_discover, ifp);
else
ipv4ll_start(ifp);
break;
default:
logger(ifp->ctx, LOG_ERR,
"%s: unknown auto configuration option %d",
ifp->name, tmp);
break;
}
}
return;
}
/* Ensure that the address offered is valid */
if ((type == 0 || type == DHCP_OFFER || type == DHCP_ACK) &&
(dhcp->ciaddr == INADDR_ANY || dhcp->ciaddr == INADDR_BROADCAST) &&
(dhcp->yiaddr == INADDR_ANY || dhcp->yiaddr == INADDR_BROADCAST))
{
rpc_signal_status("IgnoreInvalidOffer");
log_dhcp(LOG_WARNING, "reject invalid address",
ifp, dhcp, from);
return;
}
#ifdef IN_IFF_DUPLICATED
ia = ipv4_iffindaddr(ifp, &lease->addr, NULL);
if (ia && ia->addr_flags & IN_IFF_DUPLICATED) {
log_dhcp(LOG_WARNING, "declined duplicate address",
ifp, dhcp, from);
if (type)
dhcp_decline(ifp);
ipv4_deladdr(ifp, &ia->addr, &ia->net);
eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp);
eloop_timeout_add_sec(ifp->ctx->eloop,
DHCP_RAND_MAX, dhcp_discover, ifp);
return;
}
#endif
if ((type == 0 || type == DHCP_OFFER) &&
(state->state == DHS_DISCOVER || state->state == DHS_IPV4LL_BOUND))
{
if (dhcp->yiaddr == state->failed.s_addr &&
state->failed_address_offer_count == 0) {
log_dhcp(LOG_WARNING,
"reject previously declined address",
ifp, dhcp, from);
rpc_signal_status("IgnoreFailedOffer");
state->failed_address_offer_count++;
return;
}
lease->frominfo = 0;
lease->addr.s_addr = dhcp->yiaddr;
lease->cookie = dhcp->cookie;
if (type == 0 ||
get_option_addr(ifp->ctx,
&lease->server, dhcp, DHO_SERVERID) != 0)
lease->server.s_addr = INADDR_ANY;
log_dhcp(LOG_INFO, "offered", ifp, dhcp, from);
free(state->offer);
state->offer = dhcp;
*dhcpp = NULL;
if (ifp->ctx->options & DHCPCD_TEST) {
free(state->old);
state->old = state->new;
state->new = state->offer;
state->offer = NULL;
state->reason = "TEST";
script_runreason(ifp, state->reason);
eloop_exit(ifp->ctx->eloop, EXIT_SUCCESS);
return;
}
eloop_timeout_delete(ifp->ctx->eloop, send_discover, ifp);
eloop_timeout_delete(ifp->ctx->eloop, handle_nak, ifp);
/* We don't request BOOTP addresses */
if (type) {
/* We used to ARP check here, but that seems to be in
* violation of RFC2131 where it only describes
* DECLINE after REQUEST.
* It also seems that some MS DHCP servers actually
* ignore DECLINE if no REQUEST, ie we decline a
* DISCOVER. */
dhcp_request(ifp);
return;
}
}
if (type) {
if (type == DHCP_OFFER) {
log_dhcp(LOG_WARNING, "ignoring offer of",
ifp, dhcp, from);
rpc_signal_status("IgnoreAdditionalOffer");
return;
}
/* We should only be dealing with acks */
if (type != DHCP_ACK) {
log_dhcp(LOG_ERR, "not ACK or OFFER",
ifp, dhcp, from);
rpc_signal_status("IgnoreNonOffer");
return;
}
if (!(ifo->options & DHCPCD_INFORM))
log_dhcp(LOG_INFO, "acknowledged", ifp, dhcp, from);
else
ifo->options &= ~DHCPCD_STATIC;
}
/* No NAK, so reset the backoff
* We don't reset on an OFFER message because the server could
* potentially NAK the REQUEST. */
state->nakoff = 0;
/* BOOTP could have already assigned this above, so check we still
* have a pointer. */
if (*dhcpp) {
free(state->offer);
state->offer = dhcp;
*dhcpp = NULL;
}
lease->frominfo = 0;
eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp);
astate = NULL;
#ifdef IN_IFF_TENTATIVE
addr.s_addr = state->offer->yiaddr;
astate = arp_new(ifp, &addr);
if (astate) {
astate->probed_cb = dhcp_arp_probed;
astate->conflicted_cb = dhcp_arp_conflicted;
/* No need to start the probe as we'll
* listen to the kernel stating DAD or not and
* that action look look for our ARP state for
* what to do. */
}
#else
if ((ifo->options & DHCPCD_ARP || state->nak_receive_count > 0 ||
dhcp->yiaddr == state->failed.s_addr)
&& state->addr.s_addr != state->offer->yiaddr)
{
addr.s_addr = state->offer->yiaddr;
/* If the interface already has the address configured
* then we can't ARP for duplicate detection. */
ia = ipv4_findaddr(ifp->ctx, &addr);
if (ia == NULL) {
astate = arp_new(ifp, &addr);
if (astate) {
astate->probed_cb = dhcp_arp_probed;
astate->conflicted_cb = dhcp_arp_conflicted;
arp_probe(astate);
rpc_signal_status("ArpSelf");
}
return;
}
}
#endif
if ((ifo->options & DHCPCD_ARPGW) && (dhcp_probe_gw(ifp))) {
rpc_signal_status("ArpGateway");
return;
}
dhcp_bind(ifp, astate);
}
static size_t
get_udp_data(const uint8_t **data, const uint8_t *udp)
{
struct udp_dhcp_packet p;
memcpy(&p, udp, sizeof(p));
*data = udp + offsetof(struct udp_dhcp_packet, dhcp);
return ntohs(p.ip.ip_len) - sizeof(p.ip) - sizeof(p.udp);
}
static int
valid_udp_packet(const uint8_t *data, size_t data_len, struct in_addr *from,
int noudpcsum)
{
struct udp_dhcp_packet p;
uint16_t bytes, udpsum;
if (data_len < sizeof(p.ip)) {
syslog(LOG_WARNING, "packet short than an ip header "
"(len=%zd)", data_len);
if (from)
from->s_addr = INADDR_ANY;
errno = EINVAL;
return -1;
}
memcpy(&p, data, MIN(data_len, sizeof(p)));
if (from)
from->s_addr = p.ip.ip_src.s_addr;
if (data_len > sizeof(p)) {
syslog(LOG_WARNING, "packet too long (%zd bytes)", data_len);
errno = EINVAL;
return -1;
}
if (checksum(&p.ip, sizeof(p.ip)) != 0) {
syslog(LOG_WARNING, "packet failed ip header checksum");
errno = EINVAL;
return -1;
}
bytes = ntohs(p.ip.ip_len);
if (data_len < bytes) {
syslog(LOG_WARNING, "packet appears truncated "
"(len=%zd, ip_len=%zd)", data_len, bytes);
errno = EINVAL;
return -1;
}
if (noudpcsum == 0) {
udpsum = p.udp.uh_sum;
p.udp.uh_sum = 0;
p.ip.ip_hl = 0;
p.ip.ip_v = 0;
p.ip.ip_tos = 0;
p.ip.ip_len = p.udp.uh_ulen;
p.ip.ip_id = 0;
p.ip.ip_off = 0;
p.ip.ip_ttl = 0;
p.ip.ip_sum = 0;
if (udpsum && checksum(&p, bytes) != udpsum) {
syslog(LOG_WARNING, "packet failed udp checksum");
errno = EINVAL;
return -1;
}
}
return 0;
}
static void
dhcp_handlepacket(void *arg)
{
struct interface *ifp = arg;
struct dhcp_message *dhcp = NULL;
const uint8_t *pp;
size_t bytes;
struct in_addr from;
int i, flags;
const struct dhcp_state *state = D_CSTATE(ifp);
/* Need this API due to BPF */
flags = 0;
while (!(flags & RAW_EOF)) {
bytes = (size_t)if_readrawpacket(ifp, ETHERTYPE_IP,
ifp->ctx->packet, udp_dhcp_len, &flags);
if ((ssize_t)bytes == -1) {
logger(ifp->ctx, LOG_ERR,
"%s: dhcp if_readrawpacket: %m", ifp->name);
dhcp_close(ifp);
arp_close(ifp);
break;
}
if (valid_udp_packet(ifp->ctx->packet, bytes,
&from, flags & RAW_PARTIALCSUM) == -1)
{
logger(ifp->ctx, LOG_ERR,
"%s: invalid UDP packet from %s",
ifp->name, inet_ntoa(from));
continue;
}
i = whitelisted_ip(ifp->options, from.s_addr);
if (i == 0) {
logger(ifp->ctx, LOG_WARNING,
"%s: non whitelisted DHCP packet from %s",
ifp->name, inet_ntoa(from));
continue;
} else if (i != 1 &&
blacklisted_ip(ifp->options, from.s_addr) == 1)
{
logger(ifp->ctx, LOG_WARNING,
"%s: blacklisted DHCP packet from %s",
ifp->name, inet_ntoa(from));
continue;
}
if (ifp->flags & IFF_POINTOPOINT &&
state->dst.s_addr != from.s_addr)
{
logger(ifp->ctx, LOG_WARNING,
"%s: server %s is not destination",
ifp->name, inet_ntoa(from));
}
bytes = get_udp_data(&pp, ifp->ctx->packet);
if (bytes > sizeof(*dhcp)) {
logger(ifp->ctx, LOG_ERR,
"%s: packet greater than DHCP size from %s",
ifp->name, inet_ntoa(from));
continue;
}
if (dhcp == NULL) {
dhcp = calloc(1, sizeof(*dhcp));
if (dhcp == NULL) {
logger(ifp->ctx, LOG_ERR,
"%s: calloc: %m", __func__);
break;
}
}
memcpy(dhcp, pp, bytes);
if (dhcp->cookie != htonl(MAGIC_COOKIE)) {
logger(ifp->ctx, LOG_DEBUG, "%s: bogus cookie from %s",
ifp->name, inet_ntoa(from));
continue;
}
/* Ensure packet is for us */
if (ifp->hwlen <= sizeof(dhcp->chaddr) &&
memcmp(dhcp->chaddr, ifp->hwaddr, ifp->hwlen))
{
char buf[sizeof(dhcp->chaddr) * 3];
logger(ifp->ctx, LOG_DEBUG,
"%s: xid 0x%x is for hwaddr %s",
ifp->name, ntohl(dhcp->xid),
hwaddr_ntoa(dhcp->chaddr, sizeof(dhcp->chaddr),
buf, sizeof(buf)));
continue;
}
dhcp_handledhcp(ifp, &dhcp, &from);
if (state->raw_fd == -1)
break;
}
free(dhcp);
}
static void
dhcp_handleudp(void *arg)
{
struct dhcpcd_ctx *ctx;
uint8_t buffer[sizeof(struct dhcp_message)];
ctx = arg;
/* Just read what's in the UDP fd and discard it as we always read
* from the raw fd */
if (read(ctx->udp_fd, buffer, sizeof(buffer)) == -1) {
logger(ctx, LOG_ERR, "%s: %m", __func__);
eloop_event_delete(ctx->eloop, ctx->udp_fd, 0);
close(ctx->udp_fd);
ctx->udp_fd = -1;
}
}
static int
dhcp_open(struct interface *ifp)
{
struct dhcp_state *state;
if (ifp->ctx->packet == NULL) {
ifp->ctx->packet = malloc(udp_dhcp_len);
if (ifp->ctx->packet == NULL) {
logger(ifp->ctx, LOG_ERR, "%s: %m", __func__);
return -1;
}
}
state = D_STATE(ifp);
if (state->raw_fd == -1) {
state->raw_fd = if_openrawsocket(ifp, ETHERTYPE_IP);
if (state->raw_fd == -1) {
if (errno == ENOENT) {
logger(ifp->ctx, LOG_ERR,
"%s not found", if_pfname);
/* May as well disable IPv4 entirely at
* this point as we really need it. */
ifp->options->options &= ~DHCPCD_IPV4;
} else
logger(ifp->ctx, LOG_ERR, "%s: %s: %m",
__func__, ifp->name);
return -1;
}
eloop_event_add(ifp->ctx->eloop,
state->raw_fd, dhcp_handlepacket, ifp, NULL, NULL);
}
return 0;
}
int
dhcp_dump(struct interface *ifp)
{
struct dhcp_state *state;
ifp->if_data[IF_DATA_DHCP] = state = calloc(1, sizeof(*state));
if (state == NULL)
goto eexit;
state->raw_fd = state->arp_fd = -1;
TAILQ_INIT(&state->arp_states);
dhcp_set_leasefile(state->leasefile, sizeof(state->leasefile),
AF_INET, ifp, "");
state->new = read_lease(ifp);
if (state->new == NULL) {
logger(ifp->ctx, LOG_ERR, "%s: %s: %m",
*ifp->name ? ifp->name : state->leasefile, __func__);
return -1;
}
state->reason = "DUMP";
return script_runreason(ifp, state->reason);
eexit:
logger(ifp->ctx, LOG_ERR, "%s: %m", __func__);
return -1;
}
void
dhcp_free(struct interface *ifp)
{
struct dhcp_state *state = D_STATE(ifp);
struct dhcpcd_ctx *ctx;
dhcp_close(ifp);
arp_close(ifp);
if (state) {
free(state->old);
free(state->new);
free(state->offer);
free(state->buffer);
free(state->clientid);
free(state);
ifp->if_data[IF_DATA_DHCP] = NULL;
}
ctx = ifp->ctx;
/* If we don't have any more DHCP enabled interfaces,
* close the global socket and release resources */
if (ctx->ifaces) {
TAILQ_FOREACH(ifp, ctx->ifaces, next) {
if (D_STATE(ifp))
break;
}
}
if (ifp == NULL) {
if (ctx->udp_fd != -1) {
eloop_event_delete(ctx->eloop, ctx->udp_fd, 0);
close(ctx->udp_fd);
ctx->udp_fd = -1;
}
free(ctx->packet);
free(ctx->opt_buffer);
ctx->packet = NULL;
ctx->opt_buffer = NULL;
}
}
static int
dhcp_init(struct interface *ifp)
{
struct dhcp_state *state;
const struct if_options *ifo;
uint8_t len;
char buf[(sizeof(ifo->clientid) - 1) * 3];
state = D_STATE(ifp);
if (state == NULL) {
ifp->if_data[IF_DATA_DHCP] = calloc(1, sizeof(*state));
state = D_STATE(ifp);
if (state == NULL)
return -1;
/* 0 is a valid fd, so init to -1 */
state->raw_fd = state->arp_fd = -1;
TAILQ_INIT(&state->arp_states);
/* Now is a good time to find IPv4 routes */
if_initrt(ifp);
}
state->state = DHS_INIT;
state->reason = "PREINIT";
state->nakoff = 0;
dhcp_set_leasefile(state->leasefile, sizeof(state->leasefile),
AF_INET, ifp, "");
ifo = ifp->options;
/* We need to drop the leasefile so that dhcp_start
* doesn't load it. */
if (ifo->options & DHCPCD_REQUEST)
unlink(state->leasefile);
free(state->clientid);
state->clientid = NULL;
if (*ifo->clientid) {
state->clientid = malloc((size_t)(ifo->clientid[0] + 1));
if (state->clientid == NULL)
goto eexit;
memcpy(state->clientid, ifo->clientid,
(size_t)(ifo->clientid[0]) + 1);
} else if (ifo->options & DHCPCD_CLIENTID) {
if (ifo->options & DHCPCD_DUID) {
state->clientid = malloc(ifp->ctx->duid_len + 6);
if (state->clientid == NULL)
goto eexit;
state->clientid[0] =(uint8_t)(ifp->ctx->duid_len + 5);
state->clientid[1] = 255; /* RFC 4361 */
memcpy(state->clientid + 2, ifo->iaid, 4);
memcpy(state->clientid + 6, ifp->ctx->duid,
ifp->ctx->duid_len);
} else {
len = (uint8_t)(ifp->hwlen + 1);
state->clientid = malloc((size_t)len + 1);
if (state->clientid == NULL)
goto eexit;
state->clientid[0] = len;
state->clientid[1] = (uint8_t)ifp->family;
memcpy(state->clientid + 2, ifp->hwaddr,
ifp->hwlen);
}
}
if (ifo->options & DHCPCD_DUID)
/* Don't bother logging as DUID and IAID are reported
* at device start. */
return 0;
if (ifo->options & DHCPCD_CLIENTID)
logger(ifp->ctx, LOG_DEBUG, "%s: using ClientID %s", ifp->name,
hwaddr_ntoa(state->clientid + 1, state->clientid[0],
buf, sizeof(buf)));
else if (ifp->hwlen)
logger(ifp->ctx, LOG_DEBUG, "%s: using hwaddr %s", ifp->name,
hwaddr_ntoa(ifp->hwaddr, ifp->hwlen, buf, sizeof(buf)));
return 0;
eexit:
logger(ifp->ctx, LOG_ERR, "%s: error making ClientID: %m", __func__);
return -1;
}
static void
dhcp_start1(void *arg)
{
struct interface *ifp = arg;
struct if_options *ifo = ifp->options;
struct dhcp_state *state;
struct stat st;
uint32_t l;
int nolease;
if (!(ifo->options & DHCPCD_IPV4))
return;
/* Listen on *.*.*.*:bootpc so that the kernel never sends an
* ICMP port unreachable message back to the DHCP server */
if (ifp->ctx->udp_fd == -1) {
ifp->ctx->udp_fd = dhcp_openudp(NULL);
if (ifp->ctx->udp_fd == -1) {
/* Don't log an error if some other process
* is handling this. */
if (errno != EADDRINUSE)
logger(ifp->ctx, LOG_ERR,
"%s: dhcp_openudp: %m", __func__);
} else
eloop_event_add(ifp->ctx->eloop,
ifp->ctx->udp_fd, dhcp_handleudp,
ifp->ctx, NULL, NULL);
}
if (dhcp_init(ifp) == -1) {
logger(ifp->ctx, LOG_ERR, "%s: dhcp_init: %m", ifp->name);
return;
}
state = D_STATE(ifp);
state->start_uptime = uptime();
free(state->offer);
state->offer = NULL;
if (state->arping_index < ifo->arping_len) {
struct arp_state *astate;
astate = arp_new(ifp, NULL);
if (astate) {
astate->probed_cb = dhcp_arp_probed;
astate->conflicted_cb = dhcp_arp_conflicted;
dhcp_arp_probed(astate);
}
return;
}
if (ifo->options & DHCPCD_STATIC) {
dhcp_static(ifp);
return;
}
if (ifo->options & DHCPCD_DHCP && dhcp_open(ifp) == -1)
return;
if (ifo->options & DHCPCD_INFORM) {
dhcp_inform(ifp);
return;
}
if (ifp->hwlen == 0 && ifo->clientid[0] == '\0') {
logger(ifp->ctx, LOG_WARNING,
"%s: needs a clientid to configure", ifp->name);
dhcp_drop(ifp, "FAIL");
eloop_timeout_delete(ifp->ctx->eloop, NULL, ifp);
return;
}
/* We don't want to read the old lease if we NAK an old test */
nolease = state->offer && ifp->ctx->options & DHCPCD_TEST;
if (!nolease) {
state->offer = read_lease(ifp);
/* Check the saved lease matches the type we want */
if (state->offer) {
#ifdef IN_IFF_DUPLICATED
struct in_addr addr;
struct ipv4_addr *ia;
addr.s_addr = state->offer->yiaddr;
ia = ipv4_iffindaddr(ifp, &addr, NULL);
#endif
if ((IS_BOOTP(ifp, state->offer) &&
!(ifo->options & DHCPCD_BOOTP)) ||
#ifdef IN_IFF_DUPLICATED
(ia && ia->addr_flags & IN_IFF_DUPLICATED) ||
#endif
(!IS_BOOTP(ifp, state->offer) &&
ifo->options & DHCPCD_BOOTP))
{
free(state->offer);
state->offer = NULL;
}
}
}
if (state->offer) {
get_lease(ifp->ctx, &state->lease, state->offer);
state->lease.frominfo = 1;
if (state->new == NULL &&
ipv4_iffindaddr(ifp, &state->lease.addr, &state->lease.net))
{
/* We still have the IP address from the last lease.
* Fake add the address and routes from it so the lease
* can be cleaned up. */
state->new = malloc(sizeof(*state->new));
if (state->new) {
memcpy(state->new, state->offer,
sizeof(*state->new));
state->addr = state->lease.addr;
state->net = state->lease.net;
state->added |= STATE_ADDED | STATE_FAKE;
ipv4_buildroutes(ifp->ctx);
} else
logger(ifp->ctx, LOG_ERR, "%s: %m", __func__);
}
if (state->offer->cookie == 0) {
if (state->offer->yiaddr == state->addr.s_addr) {
free(state->offer);
state->offer = NULL;
}
} else if (state->lease.leasetime != ~0U &&
stat(state->leasefile, &st) == 0)
{
time_t now;
/* Offset lease times and check expiry */
now = time(NULL);
if (now == -1 ||
(time_t)state->lease.leasetime < now - st.st_mtime)
{
logger(ifp->ctx, LOG_DEBUG,
"%s: discarding expired lease", ifp->name);
free(state->offer);
state->offer = NULL;
state->lease.addr.s_addr = 0;
/* Technically we should discard the lease
* as it's expired, just as DHCPv6 addresses
* would be by the kernel.
* However, this may violate POLA so
* we currently leave it be.
* If we get a totally different lease from
* the DHCP server we'll drop it anyway, as
* we will on any other event which would
* trigger a lease drop.
* This should only happen if dhcpcd stops
* running and the lease expires before
* dhcpcd starts again. */
#if 0
if (state->new)
dhcp_drop(ifp, "EXPIRE");
#endif
} else {
l = (uint32_t)(now - st.st_mtime);
state->lease.leasetime -= l;
state->lease.renewaltime -= l;
state->lease.rebindtime -= l;
}
}
}
if (!(ifo->options & DHCPCD_DHCP)) {
if (ifo->options & DHCPCD_IPV4LL) {
if (state->offer && state->offer->cookie != 0) {
free(state->offer);
state->offer = NULL;
}
ipv4ll_start(ifp);
}
return;
}
if (state->offer == NULL || state->offer->cookie == 0)
dhcp_discover(ifp);
else
dhcp_reboot(ifp);
}
void
dhcp_start(struct interface *ifp)
{
struct timespec tv;
if (!(ifp->options->options & DHCPCD_IPV4))
return;
/* No point in delaying a static configuration */
tv.tv_sec = DHCP_MIN_DELAY;
tv.tv_nsec = (suseconds_t)arc4random_uniform(
(DHCP_MAX_DELAY - DHCP_MIN_DELAY) * NSEC_PER_SEC);
timespecnorm(&tv);
logger(ifp->ctx, LOG_DEBUG,
"%s: delaying IPv4 for %0.1f seconds",
ifp->name, timespec_to_double(&tv));
eloop_timeout_add_tv(ifp->ctx->eloop, &tv, dhcp_start1, ifp);
}
void
dhcp_handleifa(int cmd, struct interface *ifp,
const struct in_addr *addr,
const struct in_addr *net,
const struct in_addr *dst,
__unused int flags)
{
struct dhcp_state *state;
struct if_options *ifo;
uint8_t i;
state = D_STATE(ifp);
if (state == NULL)
return;
if (cmd == RTM_DELADDR) {
if (state->addr.s_addr == addr->s_addr &&
state->net.s_addr == net->s_addr)
{
logger(ifp->ctx, LOG_INFO,
"%s: removing IP address %s/%d",
ifp->name, inet_ntoa(state->addr),
inet_ntocidr(state->net));
dhcp_drop(ifp, "EXPIRE");
}
return;
}
if (cmd != RTM_NEWADDR)
return;
ifo = ifp->options;
if (ifo->options & DHCPCD_INFORM) {
if (state->state != DHS_INFORM)
dhcp_inform(ifp);
return;
}
if (!(ifo->options & DHCPCD_STATIC))
return;
if (ifo->req_addr.s_addr != INADDR_ANY)
return;
free(state->old);
state->old = state->new;
state->new = dhcp_message_new(addr, net);
if (state->new == NULL)
return;
state->dst.s_addr = dst ? dst->s_addr : INADDR_ANY;
if (dst) {
for (i = 1; i < 255; i++)
if (i != DHO_ROUTER && has_option_mask(ifo->dstmask,i))
dhcp_message_add_addr(state->new, i, *dst);
}
state->reason = "STATIC";
ipv4_buildroutes(ifp->ctx);
script_runreason(ifp, state->reason);
if (ifo->options & DHCPCD_INFORM) {
state->state = DHS_INFORM;
state->xid = dhcp_xid(ifp);
state->lease.server.s_addr = dst ? dst->s_addr : INADDR_ANY;
state->addr = *addr;
state->net = *net;
dhcp_inform(ifp);
}
}