/* 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 *
get_option_routes(const struct dhcp_message *dhcp)
{
const uint8_t *p;
const uint8_t *e;
struct rt *routes = NULL;
struct rt *route = NULL;
int len;
/* If we have CSR's then we MUST use these only */
p = get_option(dhcp, DHO_CSR, &len, NULL);
/* Check for crappy MS option */
if (!p)
p = get_option(dhcp, DHO_MSCSR, &len, NULL);
if (p) {
routes = decode_rfc3442_rt(len, p);
if (routes)
return routes;
}
/* OK, get our static routes first. */
p = get_option(dhcp, DHO_STATICROUTE, &len, NULL);
if (p) {
e = p + len;
while (p < e) {
if (route) {
route->next = xmalloc(sizeof(*route));
route = route->next;
} else
routes = route = xmalloc(sizeof(*routes));
route->next = NULL;
memcpy(&route->dest.s_addr, p, 4);
p += 4;
memcpy(&route->gate.s_addr, p, 4);
p += 4;
route->net.s_addr = route_netmask(route->dest.s_addr);
}
}
/* Now grab our routers */
p = get_option(dhcp, DHO_ROUTER, &len, NULL);
if (p) {
e = p + len;
while (p < e) {
if (route) {
route->next = xzalloc(sizeof(*route));
route = route->next;
} else
routes = route = xzalloc(sizeof(*route));
memcpy(&route->gate.s_addr, p, 4);
p += 4;
}
}
return routes;
}
int parse_dhcpmessage (dhcp_t *dhcp, const dhcpmessage_t *message)
{
const unsigned char *p = message->options;
const unsigned char *end = p; /* Add size later for gcc-3 issue */
unsigned char option;
unsigned char length;
unsigned int len = 0;
int i;
int retval = -1;
struct timeval tv;
route_t *routers = NULL;
route_t *routersp = NULL;
route_t *static_routes = NULL;
route_t *static_routesp = NULL;
route_t *csr = NULL;
bool in_overload = false;
bool parse_sname = false;
bool parse_file = false;
end += sizeof (message->options);
if (gettimeofday (&tv, NULL) == -1) {
logger (LOG_ERR, "gettimeofday: %s", strerror (errno));
return (-1);
}
dhcp->address.s_addr = message->yiaddr;
dhcp->leasedfrom = tv.tv_sec;
dhcp->frominfo = false;
dhcp->address.s_addr = message->yiaddr;
strlcpy (dhcp->servername, (char *) message->servername,
sizeof (dhcp->servername));
#define LEN_ERR \
{ \
logger (LOG_ERR, "invalid length %d for option %d", length, option); \
p += length; \
continue; \
}
parse_start:
while (p < end) {
option = *p++;
if (! option)
continue;
if (option == DHCP_END)
goto eexit;
length = *p++;
if (option != DHCP_PAD && length == 0) {
logger (LOG_ERR, "option %d has zero length", option);
retval = -1;
goto eexit;
}
if (p + length >= end) {
logger (LOG_ERR, "dhcp option exceeds message length");
retval = -1;
goto eexit;
}
switch (option) {
case DHCP_MESSAGETYPE:
retval = (int) *p;
p += length;
continue;
default:
if (length == 0) {
logger (LOG_DEBUG, "option %d has zero length, skipping",
option);
continue;
}
}
#define LENGTH(_length) \
if (length != _length) \
LEN_ERR;
#define MIN_LENGTH(_length) \
if (length < _length) \
LEN_ERR;
#define MULT_LENGTH(_mult) \
if (length % _mult != 0) \
LEN_ERR;
#define GET_UINT8(_val) \
LENGTH (sizeof (uint8_t)); \
memcpy (&_val, p, sizeof (uint8_t));
#define GET_UINT16(_val) \
LENGTH (sizeof (uint16_t)); \
memcpy (&_val, p, sizeof (uint16_t));
#define GET_UINT32(_val) \
LENGTH (sizeof (uint32_t)); \
memcpy (&_val, p, sizeof (uint32_t));
#define GET_UINT16_H(_val) \
GET_UINT16 (_val); \
_val = ntohs (_val);
#define GET_UINT32_H(_val) \
GET_UINT32 (_val); \
_val = ntohl (_val);
switch (option) {
case DHCP_ADDRESS:
GET_UINT32 (dhcp->address.s_addr);
break;
case DHCP_NETMASK:
GET_UINT32 (dhcp->netmask.s_addr);
break;
case DHCP_BROADCAST:
GET_UINT32 (dhcp->broadcast.s_addr);
break;
case DHCP_SERVERIDENTIFIER:
GET_UINT32 (dhcp->serveraddress.s_addr);
break;
case DHCP_LEASETIME:
GET_UINT32_H (dhcp->leasetime);
break;
case DHCP_RENEWALTIME:
GET_UINT32_H (dhcp->renewaltime);
break;
case DHCP_REBINDTIME:
GET_UINT32_H (dhcp->rebindtime);
break;
case DHCP_MTU:
GET_UINT16_H (dhcp->mtu);
/* Minimum legal mtu is 68 accoridng to RFC 2132.
In practise it's 576 (minimum maximum message size) */
if (dhcp->mtu < MTU_MIN) {
logger (LOG_DEBUG, "MTU %d is too low, minimum is %d; ignoring", dhcp->mtu, MTU_MIN);
dhcp->mtu = 0;
}
break;
#undef GET_UINT32_H
#undef GET_UINT32
#undef GET_UINT16_H
#undef GET_UINT16
#undef GET_UINT8
#define GETSTR(_var) \
MIN_LENGTH (sizeof (char)); \
if (_var) free (_var); \
_var = xmalloc (length + 1); \
memcpy (_var, p, length); \
memset (_var + length, 0, 1);
case DHCP_HOSTNAME:
GETSTR (dhcp->hostname);
break;
case DHCP_DNSDOMAIN:
GETSTR (dhcp->dnsdomain);
break;
case DHCP_MESSAGE:
GETSTR (dhcp->message);
break;
case DHCP_ROOTPATH:
GETSTR (dhcp->rootpath);
break;
case DHCP_NISDOMAIN:
GETSTR (dhcp->nisdomain);
break;
#undef GETSTR
#define GETADDR(_var) \
MULT_LENGTH (4); \
if (! dhcp_add_address (&_var, p, length)) \
{ \
retval = -1; \
goto eexit; \
}
case DHCP_DNSSERVER:
GETADDR (dhcp->dnsservers);
break;
case DHCP_NTPSERVER:
GETADDR (dhcp->ntpservers);
break;
case DHCP_NISSERVER:
GETADDR (dhcp->nisservers);
break;
#undef GETADDR
case DHCP_DNSSEARCH:
MIN_LENGTH (1);
free (dhcp->dnssearch);
if ((len = decode_search (p, length, NULL)) > 0) {
dhcp->dnssearch = xmalloc (len);
decode_search (p, length, dhcp->dnssearch);
}
break;
case DHCP_CSR:
MIN_LENGTH (5);
free_route (csr);
csr = decode_CSR (p, length);
break;
case DHCP_SIPSERVER:
free (dhcp->sipservers);
dhcp->sipservers = decode_sipservers (p, length);
break;
case DHCP_STATICROUTE:
MULT_LENGTH (8);
for (i = 0; i < length; i += 8) {
if (static_routesp) {
static_routesp->next = xmalloc (sizeof (route_t));
static_routesp = static_routesp->next;
} else
static_routesp = static_routes = xmalloc (sizeof (route_t));
memset (static_routesp, 0, sizeof (route_t));
memcpy (&static_routesp->destination.s_addr, p + i, 4);
memcpy (&static_routesp->gateway.s_addr, p + i + 4, 4);
static_routesp->netmask.s_addr =
route_netmask (static_routesp->destination.s_addr);
}
break;
case DHCP_ROUTERS:
MULT_LENGTH (4);
for (i = 0; i < length; i += 4)
{
if (routersp) {
routersp->next = xmalloc (sizeof (route_t));
routersp = routersp->next;
} else
routersp = routers = xmalloc (sizeof (route_t));
memset (routersp, 0, sizeof (route_t));
memcpy (&routersp->gateway.s_addr, p + i, 4);
}
break;
case DHCP_OPTIONSOVERLOADED:
LENGTH (1);
/* The overloaded option in an overloaded option
* should be ignored, overwise we may get an infinite loop */
if (! in_overload) {
if (*p & 1)
parse_file = true;
if (*p & 2)
parse_sname = true;
}
break;
#undef LENGTH
#undef MIN_LENGTH
#undef MULT_LENGTH
default:
logger (LOG_DEBUG, "no facility to parse DHCP code %u", option);
break;
}
p += length;
}
eexit:
/* We may have options overloaded, so go back and grab them */
if (parse_file) {
parse_file = false;
p = message->bootfile;
end = p + sizeof (message->bootfile);
in_overload = true;
goto parse_start;
} else if (parse_sname) {
parse_sname = false;
p = message->servername;
end = p + sizeof (message->servername);
memset (dhcp->servername, 0, sizeof (dhcp->servername));
in_overload = true;
goto parse_start;
}
/* Fill in any missing fields */
if (! dhcp->netmask.s_addr)
dhcp->netmask.s_addr = get_netmask (dhcp->address.s_addr);
if (! dhcp->broadcast.s_addr)
dhcp->broadcast.s_addr = dhcp->address.s_addr | ~dhcp->netmask.s_addr;
/* If we have classess static routes then we discard
static routes and routers according to RFC 3442 */
if (csr) {
dhcp->routes = csr;
free_route (routers);
free_route (static_routes);
} else {
/* Ensure that we apply static routes before routers */
if (static_routes)
{
dhcp->routes = static_routes;
static_routesp->next = routers;
} else
dhcp->routes = routers;
}
return retval;
}
