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/*
* dhcp.c Functions to send/receive dhcp packets.
*
* Version: $Id$
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
*
* Copyright 2008 The FreeRADIUS server project
* Copyright 2008 Alan DeKok <aland@deployingradius.com>
*/
#include <freeradius-devel/ident.h>
RCSID("$Id$")
#include <freeradius-devel/libradius.h>
#include <freeradius-devel/udpfromto.h>
#include <freeradius-devel/dhcp.h>
#ifdef WITH_DHCP
#define DHCP_CHADDR_LEN (16)
#define DHCP_SNAME_LEN (64)
#define DHCP_FILE_LEN (128)
#define DHCP_VEND_LEN (308)
#define DHCP_OPTION_MAGIC_NUMBER (0x63825363)
#ifndef INADDR_BROADCAST
#define INADDR_BROADCAST INADDR_NONE
#endif
typedef struct dhcp_packet_t {
uint8_t opcode;
uint8_t htype;
uint8_t hlen;
uint8_t hops;
uint32_t xid; /* 4 */
uint16_t secs; /* 8 */
uint16_t flags;
uint32_t ciaddr; /* 12 */
uint32_t yiaddr; /* 16 */
uint32_t siaddr; /* 20 */
uint32_t giaddr; /* 24 */
uint8_t chaddr[DHCP_CHADDR_LEN]; /* 28 */
uint8_t sname[DHCP_SNAME_LEN]; /* 44 */
uint8_t file[DHCP_FILE_LEN]; /* 108 */
uint32_t option_format; /* 236 */
uint8_t options[DHCP_VEND_LEN];
} dhcp_packet_t;
typedef struct dhcp_option_t {
uint8_t code;
uint8_t length;
} dhcp_option_t;
/*
* INADDR_ANY : 68 -> INADDR_BROADCAST : 67 DISCOVER
* INADDR_BROADCAST : 68 <- SERVER_IP : 67 OFFER
* INADDR_ANY : 68 -> INADDR_BROADCAST : 67 REQUEST
* INADDR_BROADCAST : 68 <- SERVER_IP : 67 ACK
*/
static const char *dhcp_header_names[] = {
"DHCP-Opcode",
"DHCP-Hardware-Type",
"DHCP-Hardware-Address-Length",
"DHCP-Hop-Count",
"DHCP-Transaction-Id",
"DHCP-Number-of-Seconds",
"DHCP-Flags",
"DHCP-Client-IP-Address",
"DHCP-Your-IP-Address",
"DHCP-Server-IP-Address",
"DHCP-Gateway-IP-Address",
"DHCP-Client-Hardware-Address",
"DHCP-Server-Host-Name",
"DHCP-Boot-Filename",
NULL
};
static const char *dhcp_message_types[] = {
"invalid",
"DHCP-Discover",
"DHCP-Offer",
"DHCP-Request",
"DHCP-Decline",
"DHCP-Ack",
"DHCP-NAK",
"DHCP-Release",
"DHCP-Inform",
"DHCP-Force-Renew",
};
static int dhcp_header_sizes[] = {
1, 1, 1, 1,
4, 2, 2, 4,
4, 4, 4,
DHCP_CHADDR_LEN,
DHCP_SNAME_LEN,
DHCP_FILE_LEN
};
/*
* Some clients silently ignore responses less than 300 bytes.
*/
#define MIN_PACKET_SIZE (244)
#define DEFAULT_PACKET_SIZE (300)
#define MAX_PACKET_SIZE (1500 - 40)
#define DHCP_OPTION_FIELD (0)
#define DHCP_FILE_FIELD (1)
#define DHCP_SNAME_FIELD (2)
static uint8_t *dhcp_get_option(dhcp_packet_t *packet, size_t packet_size,
unsigned int option)
{
int overload = 0;
int field = DHCP_OPTION_FIELD;
size_t where, size;
uint8_t *data = packet->options;
where = 0;
size = packet_size - offsetof(dhcp_packet_t, options);
data = &packet->options[where];
while (where < size) {
if (data[0] == 0) { /* padding */
where++;
continue;
}
if (data[0] == 255) { /* end of options */
if ((field == DHCP_OPTION_FIELD) &&
(overload & DHCP_FILE_FIELD)) {
data = packet->file;
where = 0;
size = sizeof(packet->file);
field = DHCP_FILE_FIELD;
continue;
} else if ((field == DHCP_FILE_FIELD) &&
(overload && DHCP_SNAME_FIELD)) {
data = packet->sname;
where = 0;
size = sizeof(packet->sname);
field = DHCP_SNAME_FIELD;
continue;
}
return NULL;
}
/*
* We MUST have a real option here.
*/
if ((where + 2) > size) {
fr_strerror_printf("Options overflow field at %u",
(unsigned int) (data - (uint8_t *) packet));
return NULL;
}
if ((where + 2 + data[1]) > size) {
fr_strerror_printf("Option length overflows field at %u",
(unsigned int) (data - (uint8_t *) packet));
return NULL;
}
if (data[0] == option) return data;
if (data[0] == 52) { /* overload sname and/or file */
overload = data[3];
}
where += data[1] + 2;
data += data[1] + 2;
}
return NULL;
}
/*
* DHCPv4 is only for IPv4. Broadcast only works if udpfromto is
* defined.
*/
RADIUS_PACKET *fr_dhcp_recv(int sockfd)
{
uint32_t magic;
struct sockaddr_storage src;
struct sockaddr_storage dst;
socklen_t sizeof_src;
socklen_t sizeof_dst;
RADIUS_PACKET *packet;
int port;
uint8_t *code;
packet = rad_alloc(0);
if (!packet) {
fr_strerror_printf("Failed allocating packet");
return NULL;
}
memset(packet, 0, sizeof(packet));
packet->data = malloc(MAX_PACKET_SIZE);
if (!packet->data) {
fr_strerror_printf("Failed in malloc");
rad_free(&packet);
return NULL;
}
packet->sockfd = sockfd;
sizeof_src = sizeof(src);
#ifdef WITH_UDPFROMTO
sizeof_dst = sizeof(dst);
packet->data_len = recvfromto(sockfd, packet->data, MAX_PACKET_SIZE, 0,
(struct sockaddr *)&src, &sizeof_src,
(struct sockaddr *)&dst, &sizeof_dst);
#else
packet->data_len = recvfrom(sockfd, packet->data, MAX_PACKET_SIZE, 0,
(struct sockaddr *)&src, &sizeof_src);
#endif
if (packet->data_len <= 0) {
fr_strerror_printf("Failed reading DHCP socket: %s", strerror(errno));
rad_free(&packet);
return NULL;
}
if (packet->data_len < MIN_PACKET_SIZE) {
fr_strerror_printf("DHCP packet is too small (%d < %d)",
packet->data_len, MIN_PACKET_SIZE);
rad_free(&packet);
return NULL;
}
if (packet->data[1] != 1) {
fr_strerror_printf("DHCP can only receive ethernet requests, not type %02x",
packet->data[1]);
rad_free(&packet);
return NULL;
}
if (packet->data[2] != 6) {
fr_strerror_printf("Ethernet HW length is wrong length %d",
packet->data[2]);
rad_free(&packet);
return NULL;
}
memcpy(&magic, packet->data + 236, 4);
magic = ntohl(magic);
if (magic != DHCP_OPTION_MAGIC_NUMBER) {
fr_strerror_printf("Cannot do BOOTP");
rad_free(&packet);
return NULL;
}
/*
* Create unique keys for the packet.
*/
memcpy(&magic, packet->data + 4, 4);
packet->id = ntohl(magic);
code = dhcp_get_option((dhcp_packet_t *) packet->data,
packet->data_len, 53);
if (!code) {
fr_strerror_printf("No message-type option was found in the packet");
rad_free(&packet);
return NULL;
}
if ((code[1] < 1) || (code[2] == 0) || (code[2] > 8)) {
fr_strerror_printf("Unknown value for message-type option");
rad_free(&packet);
return NULL;
}
packet->code = code[2] | PW_DHCP_OFFSET;
/*
* Create a unique vector from the MAC address and the
* DHCP opcode. This is a hack for the RADIUS
* infrastructure in the rest of the server.
*
* Note: packet->data[2] == 6, which is smaller than
* sizeof(packet->vector)
*
* FIXME: Look for client-identifier in packet,
* and use that, too?
*/
memset(packet->vector, 0, sizeof(packet->vector));
memcpy(packet->vector, packet->data + 28, packet->data[2]);
packet->vector[packet->data[2]] = packet->code & 0xff;
/*
* FIXME: for DISCOVER / REQUEST: src_port == dst_port + 1
* FIXME: for OFFER / ACK : src_port = dst_port - 1
*/
/*
* Unique keys are xid, client mac, and client ID?
*/
/*
* FIXME: More checks, like DHCP packet type?
*/
sizeof_dst = sizeof(dst);
#ifndef WITH_UDPFROMTO
/*
* This should never fail...
*/
getsockname(sockfd, (struct sockaddr *) &dst, &sizeof_dst);
#endif
fr_sockaddr2ipaddr(&dst, sizeof_dst, &packet->dst_ipaddr, &port);
packet->dst_port = port;
fr_sockaddr2ipaddr(&src, sizeof_src, &packet->src_ipaddr, &port);
packet->src_port = port;
if (fr_debug_flag > 1) {
char type_buf[64];
const char *name = type_buf;
char src_ip_buf[256], dst_ip_buf[256];
if ((packet->code >= PW_DHCP_DISCOVER) &&
(packet->code <= PW_DHCP_INFORM)) {
name = dhcp_message_types[packet->code - PW_DHCP_OFFSET];
} else {
snprintf(type_buf, sizeof(type_buf), "%d",
packet->code - PW_DHCP_OFFSET);
}
DEBUG("Received %s of id %08x from %s:%d to %s:%d",
name, (unsigned int) packet->id,
inet_ntop(packet->src_ipaddr.af,
&packet->src_ipaddr.ipaddr,
src_ip_buf, sizeof(src_ip_buf)),
packet->src_port,
inet_ntop(packet->dst_ipaddr.af,
&packet->dst_ipaddr.ipaddr,
dst_ip_buf, sizeof(dst_ip_buf)),
packet->dst_port);
}
return packet;
}
/*
* Send a DHCP packet.
*/
int fr_dhcp_send(RADIUS_PACKET *packet)
{
struct sockaddr_storage dst;
socklen_t sizeof_dst;
#ifdef WITH_UDPFROMTO
struct sockaddr_storage src;
socklen_t sizeof_src;
#endif
fr_ipaddr2sockaddr(&packet->dst_ipaddr, packet->dst_port,
&dst, &sizeof_dst);
#ifndef WITH_UDPFROMTO
/*
* Assume that the packet is encoded before sending it.
*/
return sendto(packet->sockfd, packet->data, packet->data_len, 0,
(struct sockaddr *)&dst, sizeof_dst);
#else
fr_ipaddr2sockaddr(&packet->src_ipaddr, packet->src_port,
&src, &sizeof_src);
return sendfromto(packet->sockfd,
packet->data, packet->data_len, 0,
(struct sockaddr *)&src, sizeof_src,
(struct sockaddr *)&dst, sizeof_dst);
#endif
}
static int fr_dhcp_attr2vp(VALUE_PAIR *vp, const uint8_t *p, size_t alen);
static int decode_tlv(VALUE_PAIR *tlv, const uint8_t *data, size_t data_len)
{
const uint8_t *p;
VALUE_PAIR *head, **tail, *vp;
/*
* Take a pass at parsing it.
*/
p = data;
while (p < (data + data_len)) {
if ((p + 2) > (data + data_len)) goto make_tlv;
if ((p + p[1] + 2) > (data + data_len)) goto make_tlv;
p += 2 + p[1];
}
/*
* Got here... must be well formed.
*/
head = NULL;
tail = &head;
p = data;
while (p < (data + data_len)) {
vp = paircreate(tlv->attribute | (p[0] << 8), PW_TYPE_OCTETS);
if (!vp) {
pairfree(&head);
goto make_tlv;
}
if (fr_dhcp_attr2vp(vp, p + 2, p[1]) < 0) {
pairfree(&head);
goto make_tlv;
}
*tail = vp;
tail = &(vp->next);
p += 2 + p[1];
}
/*
* The caller allocated TLV, so we need to copy the FIRST
* attribute over top of that.
*/
memcpy(tlv, head, sizeof(*tlv));
head->next = NULL;
pairfree(&head);
return 0;
make_tlv:
tlv->vp_tlv = malloc(data_len);
if (!tlv->vp_tlv) {
fr_strerror_printf("No memory");
return -1;
}
memcpy(tlv->vp_tlv, data, data_len);
tlv->length = data_len;
return 0;
}
/*
* Decode ONE value into a VP
*/
static int fr_dhcp_attr2vp(VALUE_PAIR *vp, const uint8_t *p, size_t alen)
{
switch (vp->type) {
case PW_TYPE_BYTE:
if (alen != 1) goto raw;
vp->vp_integer = p[0];
break;
case PW_TYPE_SHORT:
if (alen != 2) goto raw;
vp->vp_integer = (p[0] << 8) | p[1];
break;
case PW_TYPE_INTEGER:
if (alen != 4) goto raw;
memcpy(&vp->vp_integer, p, 4);
vp->vp_integer = ntohl(vp->vp_integer);
break;
case PW_TYPE_IPADDR:
if (alen != 4) goto raw;
memcpy(&vp->vp_ipaddr, p , 4);
vp->length = 4;
break;
case PW_TYPE_STRING:
if (alen > 253) return -1;
memcpy(vp->vp_strvalue, p , alen);
vp->vp_strvalue[alen] = '\0';
break;
raw:
vp->type = PW_TYPE_OCTETS;
case PW_TYPE_OCTETS:
if (alen > 253) return -1;
memcpy(vp->vp_octets, p, alen);
break;
case PW_TYPE_TLV:
return decode_tlv(vp, p, alen);
default:
fr_strerror_printf("Internal sanity check %d %d", vp->type, __LINE__);
break;
} /* switch over type */
vp->length = alen;
return 0;
}
int fr_dhcp_decode(RADIUS_PACKET *packet)
{
int i;
uint8_t *p, *next;
uint32_t giaddr;
VALUE_PAIR *head, *vp, **tail;
VALUE_PAIR *maxms, *mtu;
char buffer[2048];
head = NULL;
tail = &head;
p = packet->data;
if ((fr_debug_flag > 2) && fr_log_fp) {
for (i = 0; i < packet->data_len; i++) {
if ((i & 0x0f) == 0x00) fr_strerror_printf("%d: ", i);
fprintf(fr_log_fp, "%02x ", packet->data[i]);
if ((i & 0x0f) == 0x0f) fprintf(fr_log_fp, "\n");
}
fprintf(fr_log_fp, "\n");
}
if (packet->data[1] != 1) {
fr_strerror_printf("Packet is not Ethernet: %u",
packet->data[1]);
return -1;
}
/*
* Decode the header.
*/
for (i = 0; i < 14; i++) {
vp = pairmake(dhcp_header_names[i], NULL, T_OP_EQ);
if (!vp) {
fr_strerror_printf("Parse error %s", fr_strerror());
pairfree(&head);
return -1;
}
if ((i == 11) &&
(packet->data[1] == 1) &&
(packet->data[2] == 6)) {
vp->type = PW_TYPE_ETHERNET;
}
switch (vp->type) {
case PW_TYPE_BYTE:
vp->vp_integer = p[0];
vp->length = 1;
break;
case PW_TYPE_SHORT:
vp->vp_integer = (p[0] << 8) | p[1];
vp->length = 2;
break;
case PW_TYPE_INTEGER:
memcpy(&vp->vp_integer, p, 4);
vp->vp_integer = ntohl(vp->vp_integer);
vp->length = 4;
break;
case PW_TYPE_IPADDR:
memcpy(&vp->vp_ipaddr, p, 4);
vp->length = 4;
break;
case PW_TYPE_STRING:
memcpy(vp->vp_strvalue, p, dhcp_header_sizes[i]);
vp->vp_strvalue[dhcp_header_sizes[i]] = '\0';
vp->length = strlen(vp->vp_strvalue);
if (vp->length == 0) {
pairfree(&vp);
}
break;
case PW_TYPE_OCTETS:
memcpy(vp->vp_octets, p, packet->data[2]);
vp->length = packet->data[2];
break;
case PW_TYPE_ETHERNET:
memcpy(vp->vp_ether, p, sizeof(vp->vp_ether));
vp->length = sizeof(vp->vp_ether);
break;
default:
fr_strerror_printf("BAD TYPE %d", vp->type);
pairfree(&vp);
break;
}
p += dhcp_header_sizes[i];
if (!vp) continue;
if (fr_debug_flag > 1) {
vp_prints(buffer, sizeof(buffer), vp);
fr_strerror_printf("\t%s", buffer);
}
*tail = vp;
tail = &vp->next;
}
/*
* Loop over the options.
*/
next = packet->data + 240;
/*
* FIXME: This should also check sname && file fields.
* See the dhcp_get_option() function above.
*/
while (next < (packet->data + packet->data_len)) {
int num_entries, alen;
DICT_ATTR *da;
p = next;
if (*p == 0) break;
if (*p == 255) break; /* end of options signifier */
if ((p + 2) > (packet->data + packet->data_len)) break;
next = p + 2 + p[1];
if (p[1] >= 253) {
fr_strerror_printf("Attribute too long %u %u",
p[0], p[1]);
continue;
}
da = dict_attrbyvalue(DHCP2ATTR(p[0]));
if (!da) {
fr_strerror_printf("Attribute not in our dictionary: %u",
p[0]);
continue;
}
vp = NULL;
num_entries = 1;
alen = p[1];
p += 2;
/*
* Could be an array of bytes, integers, etc.
*/
if (da->flags.array) {
switch (da->type) {
case PW_TYPE_BYTE:
num_entries = alen;
alen = 1;
break;
case PW_TYPE_SHORT: /* ignore any trailing data */
num_entries = alen >> 1;
alen = 2;
break;
case PW_TYPE_IPADDR:
case PW_TYPE_INTEGER:
case PW_TYPE_DATE: /* ignore any trailing data */
num_entries = alen >> 2;
alen = 4;
break;
default:
break; /* really an internal sanity failure */
}
}
/*
* Loop over all of the entries, building VPs
*/
for (i = 0; i < num_entries; i++) {
vp = pairmake(da->name, NULL, T_OP_EQ);
if (!vp) {
fr_strerror_printf("Cannot build attribute %s",
fr_strerror());
pairfree(&head);
return -1;
}
/*
* Hack for ease of use.
*/
if ((da->attr == DHCP2ATTR(0x3d)) &&
!da->flags.array &&
(alen == 7) && (*p == 1) && (num_entries == 1)) {
vp->type = PW_TYPE_ETHERNET;
memcpy(vp->vp_octets, p + 1, 6);
vp->length = alen;
} else if (fr_dhcp_attr2vp(vp, p, alen) < 0) {
pairfree(&vp);
pairfree(&head);
return -1;
}
if (fr_debug_flag > 1) {
vp_prints(buffer, sizeof(buffer), vp);
fr_strerror_printf("\t%s", buffer);
}
*tail = vp;
while (*tail) tail = &(*tail)->next;
p += alen;
} /* loop over array entries */
} /* loop over the entire packet */
/*
* If DHCP request, set ciaddr to zero.
*/
/*
* Set broadcast flag for broken vendors, but only if
* giaddr isn't set.
*/
memcpy(&giaddr, packet->data + 24, sizeof(giaddr));
if (giaddr == htonl(INADDR_ANY)) {
/*
* DHCP Opcode is request
*/
vp = pairfind(head, DHCP2ATTR(256));
if (vp && vp->lvalue == 3) {
/*
* Vendor is "MSFT 98"
*/
vp = pairfind(head, DHCP2ATTR(63));
if (vp && (strcmp(vp->vp_strvalue, "MSFT 98") == 0)) {
vp = pairfind(head, DHCP2ATTR(262));
/*
* Reply should be broadcast.
*/
if (vp) vp->lvalue |= 0x8000;
packet->data[10] |= 0x80;
}
}
}
/*
* FIXME: Nuke attributes that aren't used in the normal
* header for discover/requests.
*/
packet->vps = head;
/*
* Client can request a LARGER size, but not a smaller
* one. They also cannot request a size larger than MTU.
*/
maxms = pairfind(packet->vps, DHCP2ATTR(57));
mtu = pairfind(packet->vps, DHCP2ATTR(26));
if (mtu && (mtu->vp_integer < DEFAULT_PACKET_SIZE)) {
fr_strerror_printf("DHCP Fatal: Client says MTU is smaller than minimum permitted by the specification.");
return -1;
}
if (maxms && (maxms->vp_integer < DEFAULT_PACKET_SIZE)) {
fr_strerror_printf("DHCP WARNING: Client says maximum message size is smaller than minimum permitted by the specification: fixing it");
maxms->vp_integer = DEFAULT_PACKET_SIZE;
}
if (maxms && mtu && (maxms->vp_integer > mtu->vp_integer)) {
fr_strerror_printf("DHCP WARNING: Client says MTU is smaller than maximum message size: fixing it");
maxms->vp_integer = mtu->vp_integer;
}
if (fr_debug_flag) fflush(stdout);
return 0;
}
static int attr_cmp(const void *one, const void *two)
{
const VALUE_PAIR * const *a = one;
const VALUE_PAIR * const *b = two;
/*
* DHCP-Message-Type is first, for simplicity.
*/
if (((*a)->attribute == DHCP2ATTR(53)) &&
(*b)->attribute != DHCP2ATTR(53)) return -1;
/*
* Relay-Agent is last
*/
if (((*a)->attribute == DHCP2ATTR(82)) &&
(*b)->attribute != DHCP2ATTR(82)) return +1;
return ((*a)->attribute - (*b)->attribute);
}
static size_t fr_dhcp_vp2attr(VALUE_PAIR *vp, uint8_t *p, size_t room)
{
size_t length;
uint32_t lvalue;
/*
* FIXME: Check room!
*/
room = room; /* -Wunused */
/*
* Search for all attributes of the same
* type, and pack them into the same
* attribute.
*/
switch (vp->type) {
case PW_TYPE_BYTE:
length = 1;
*p = vp->vp_integer & 0xff;
break;
case PW_TYPE_SHORT:
length = 2;
p[0] = (vp->vp_integer >> 8) & 0xff;
p[1] = vp->vp_integer & 0xff;
break;
case PW_TYPE_INTEGER:
length = 4;
lvalue = htonl(vp->vp_integer);
memcpy(p, &lvalue, 4);
break;
case PW_TYPE_IPADDR:
length = 4;
memcpy(p, &vp->vp_ipaddr, 4);
break;
case PW_TYPE_ETHERNET:
length = 6;
memcpy(p, &vp->vp_ether, 6);
break;
case PW_TYPE_STRING:
memcpy(p, vp->vp_strvalue, vp->length);
length = vp->length;
break;
case PW_TYPE_TLV: /* FIXME: split it on 255? */
memcpy(p, vp->vp_tlv, vp->length);
length = vp->length;
break;
case PW_TYPE_OCTETS:
memcpy(p, vp->vp_octets, vp->length);
length = vp->length;
break;
default:
fr_strerror_printf("BAD TYPE2 %d", vp->type);
length = 0;
break;
}
return length;
}
static VALUE_PAIR *fr_dhcp_vp2suboption(VALUE_PAIR *vps)
{
int length;
unsigned int attribute;
uint8_t *ptr;
VALUE_PAIR *vp, *tlv;
attribute = vps->attribute & 0xffff00ff;
tlv = paircreate(attribute, PW_TYPE_TLV);
if (!tlv) return NULL;
tlv->length = 0;
for (vp = vps; vp != NULL; vp = vp->next) {
/*
* Group the attributes ONLY until we see a
* non-TLV attribute.
*/
if (!vp->flags.is_tlv ||
vp->flags.encoded ||
((vp->attribute & 0xffff00ff) != attribute)) {
break;
}
tlv->length += vp->length + 2;
}
if (!tlv->length) {
pairfree(&tlv);
return NULL;
}
tlv->vp_tlv = malloc(tlv->length);
if (!tlv->vp_tlv) {
pairfree(&tlv);
return NULL;
}
ptr = tlv->vp_tlv;
for (vp = vps; vp != NULL; vp = vp->next) {
if (!vp->flags.is_tlv ||
vp->flags.encoded ||
((vp->attribute & 0xffff00ff) != attribute)) {
break;
}
length = fr_dhcp_vp2attr(vp, ptr + 2,
tlv->vp_tlv + tlv->length - ptr);
if (length > 255) return NULL;
/*
* Pack the attribute.
*/
ptr[0] = (vp->attribute & 0xff00) >> 8;
ptr[1] = length;
ptr += length + 2;
vp->flags.encoded = 1;
}
return tlv;
}
int fr_dhcp_encode(RADIUS_PACKET *packet, RADIUS_PACKET *original)
{
int i, num_vps;
uint8_t *p;
VALUE_PAIR *vp;
uint32_t lvalue, mms;
size_t dhcp_size, length;
dhcp_packet_t *dhcp;
char buffer[1024];
if (packet->data) return 0;
packet->data = malloc(MAX_PACKET_SIZE);
if (!packet->data) return -1;
packet->data_len = MAX_PACKET_SIZE;
if (packet->code == 0) packet->code = PW_DHCP_NAK;
/*
* If there's a request, use it as a template.
* Otherwise, assume that the caller has set up
* everything appropriately.
*/
if (original) {
packet->dst_ipaddr.af = AF_INET;
packet->src_ipaddr.af = AF_INET;
packet->dst_port = original->src_port;
packet->src_port = original->dst_port;
/*
* Note that for DHCP, we NEVER send the response
* to the source IP address of the request. It
* may have traversed multiple relays, and we
* need to send the request to the relay closest
* to the client.
*
* if giaddr, send to giaddr.
* if NAK, send broadcast packet
* if ciaddr, unicast to ciaddr
* if flags & 0x8000, broadcast (client request)
* if sent from 0.0.0.0, broadcast response
* unicast to client yiaddr
*/
/*
* FIXME: alignment issues. We likely don't want to
* de-reference the packet structure directly..
*/
dhcp = (dhcp_packet_t *) original->data;
if (dhcp->giaddr != htonl(INADDR_ANY)) {
packet->dst_ipaddr.ipaddr.ip4addr.s_addr = dhcp->giaddr;
if (dhcp->giaddr != htonl(INADDR_LOOPBACK)) {
packet->dst_port = original->dst_port;
} else {
packet->dst_port = original->src_port; /* debugging */
}
} else if (packet->code == PW_DHCP_NAK) {
packet->dst_ipaddr.ipaddr.ip4addr.s_addr = htonl(INADDR_BROADCAST);
} else if (dhcp->ciaddr != htonl(INADDR_ANY)) {
packet->dst_ipaddr.ipaddr.ip4addr.s_addr = dhcp->ciaddr;
} else if ((dhcp->flags & 0x8000) != 0) {
packet->dst_ipaddr.ipaddr.ip4addr.s_addr = htonl(INADDR_BROADCAST);
} else if (packet->dst_ipaddr.ipaddr.ip4addr.s_addr == htonl(INADDR_ANY)) {
packet->dst_ipaddr.ipaddr.ip4addr.s_addr = htonl(INADDR_BROADCAST);
} else if (dhcp->yiaddr != htonl(INADDR_ANY)) {
packet->dst_ipaddr.ipaddr.ip4addr.s_addr = dhcp->yiaddr;
} else {
/* leave destination IP alone. */
}
/*
* Rewrite the source IP to be our own, if we know it.
*/
if (packet->src_ipaddr.ipaddr.ip4addr.s_addr == htonl(INADDR_BROADCAST)) {
packet->src_ipaddr.ipaddr.ip4addr.s_addr = htonl(INADDR_ANY);
}
} else {
memset(packet->data, 0, packet->data_len);
}
if (fr_debug_flag > 1) {
char type_buf[64];
const char *name = type_buf;
char src_ip_buf[256], dst_ip_buf[256];
if ((packet->code >= PW_DHCP_DISCOVER) &&
(packet->code <= PW_DHCP_INFORM)) {
name = dhcp_message_types[packet->code - PW_DHCP_OFFSET];
} else {
snprintf(type_buf, sizeof(type_buf), "%d",
packet->code - PW_DHCP_OFFSET);
}
DEBUG("Sending %s of id %08x from %s:%d to %s:%d",
name, (unsigned int) packet->id,
inet_ntop(packet->src_ipaddr.af,
&packet->src_ipaddr.ipaddr,
src_ip_buf, sizeof(src_ip_buf)),
packet->src_port,
inet_ntop(packet->dst_ipaddr.af,
&packet->dst_ipaddr.ipaddr,
dst_ip_buf, sizeof(dst_ip_buf)),
packet->dst_port);
}
p = packet->data;
mms = DEFAULT_PACKET_SIZE; /* maximum message size */
if (original) {
/*
* Clients can request a LARGER size, but not a
* smaller one. They also cannot request a size
* larger than MTU.
*/
vp = pairfind(original->vps, DHCP2ATTR(57));
if (vp && (vp->vp_integer > mms)) {
mms = vp->vp_integer;
if (mms > MAX_PACKET_SIZE) mms = MAX_PACKET_SIZE;
}
}
/*
* RFC 3118: Authentication option.
*/
vp = pairfind(packet->vps, DHCP2ATTR(90));
if (vp) {
if (vp->length < 2) {
memset(vp->vp_octets + vp->length, 0,
2 - vp->length);
vp->length = 2;
}
if (vp->length < 3) {
struct timeval tv;
gettimeofday(&tv, NULL);
vp->vp_octets[2] = 0;
timeval2ntp(&tv, vp->vp_octets + 3);
vp->length = 3 + 8;
}
/*
* Configuration token (clear-text token)
*/
if (vp->vp_octets[0] == 0) {
VALUE_PAIR *pass;
vp->vp_octets[1] = 0;
pass = pairfind(packet->vps, PW_CLEARTEXT_PASSWORD);
if (pass) {
length = pass->length;
if ((length + 11) > sizeof(vp->vp_octets)) {
length -= ((length + 11) - sizeof(vp->vp_octets));
}
memcpy(vp->vp_octets + 11, pass->vp_strvalue,
length);
vp->length = length + 11;
} else {
vp->length = 11 + 8;
memset(vp->vp_octets + 11, 0, 8);
vp->length = 11 + 8;
}
} else { /* we don't support this type! */
fr_strerror_printf("DHCP-Authentication %d unsupported",
vp->vp_octets[0]);
}
}
if (!original) {
*p++ = 1; /* client message */
} else {
*p++ = 2; /* server message */
}
*p++ = 1; /* hardware type = ethernet */
*p++ = 6; /* 6 bytes of ethernet */
*p++ = 0; /* hops */
if (original) { /* Xid */
memcpy(p, original->data + 4, 4);
} else {
lvalue = fr_rand();
memcpy(p, &lvalue, 4);
}
p += 4;
memset(p, 0, 2); /* secs are zero */
p += 2;
if (original) {
memcpy(p, original->data + 10, 6); /* copy flags && ciaddr */
}
/*
* Allow the admin to set the broadcast flag.
*/
vp = pairfind(packet->vps, DHCP2ATTR(262));
if (vp) {
p[0] |= (vp->vp_integer & 0xff00) >> 8;
p[1] |= (vp->vp_integer & 0xff);
}
p += 6;
/*
* Set client IP address.
*/
vp = pairfind(packet->vps, DHCP2ATTR(264)); /* Your IP address */
if (vp) {
lvalue = vp->vp_ipaddr;
} else {
lvalue = htonl(INADDR_ANY);
}
memcpy(p, &lvalue, 4); /* your IP address */
p += 4;
vp = pairfind(packet->vps, DHCP2ATTR(265)); /* server IP address */
if (!vp) vp = pairfind(packet->vps, DHCP2ATTR(54)); /* identifier */
if (vp) {
lvalue = vp->vp_ipaddr;
} else {
lvalue = htonl(INADDR_ANY);
}
memcpy(p, &lvalue, 4); /* Server IP address */
p += 4;
if (original) {
memcpy(p, original->data + 24, 4); /* copy gateway IP address */
} else {
vp = pairfind(packet->vps, DHCP2ATTR(266));
if (vp) {
lvalue = vp->vp_ipaddr;
} else {
lvalue = htonl(INADDR_NONE);
}
memcpy(p, &lvalue, 4);
}
p += 4;
if (original) {
memcpy(p, original->data + 28, DHCP_CHADDR_LEN);
} else {
vp = pairfind(packet->vps, DHCP2ATTR(267));
if (vp) {
if (vp->length > DHCP_CHADDR_LEN) {
memcpy(p, vp->vp_octets, DHCP_CHADDR_LEN);
} else {
memcpy(p, vp->vp_octets, vp->length);
}
}
}
p += DHCP_CHADDR_LEN;
memset(p, 0, 192); /* bootp legacy */
p += 192;
lvalue = htonl(DHCP_OPTION_MAGIC_NUMBER); /* DHCP magic number */
memcpy(p, &lvalue, 4);
p += 4;
/*
* Print the header.
*/
if (fr_debug_flag > 1) {
uint8_t *pp = p;
p = packet->data;
for (i = 0; i < 14; i++) {
vp = pairmake(dhcp_header_names[i], NULL, T_OP_EQ);
if (!vp) {
fr_strerror_printf("Parse error %s", fr_strerror());
return -1;
}
switch (vp->type) {
case PW_TYPE_BYTE:
vp->vp_integer = p[0];
vp->length = 1;
break;
case PW_TYPE_SHORT:
vp->vp_integer = (p[0] << 8) | p[1];
vp->length = 2;
break;
case PW_TYPE_INTEGER:
memcpy(&vp->vp_integer, p, 4);
vp->vp_integer = ntohl(vp->vp_integer);
vp->length = 4;
break;
case PW_TYPE_IPADDR:
memcpy(&vp->vp_ipaddr, p, 4);
vp->length = 4;
break;
case PW_TYPE_STRING:
memcpy(vp->vp_strvalue, p, dhcp_header_sizes[i]);
vp->vp_strvalue[dhcp_header_sizes[i]] = '\0';
vp->length = strlen(vp->vp_strvalue);
break;
case PW_TYPE_OCTETS: /* only for Client HW Address */
memcpy(vp->vp_octets, p, packet->data[2]);
vp->length = packet->data[2];
break;
case PW_TYPE_ETHERNET: /* only for Client HW Address */
memcpy(vp->vp_ether, p, sizeof(vp->vp_ether));
vp->length = sizeof(vp->vp_ether);
break;
default:
fr_strerror_printf("Internal sanity check failed %d %d", vp->type, __LINE__);
pairfree(&vp);
break;
}
p += dhcp_header_sizes[i];
vp_prints(buffer, sizeof(buffer), vp);
fr_strerror_printf("\t%s", buffer);
pairfree(&vp);
}
/*
* Jump over DHCP magic number, response, etc.
*/
p = pp;
}
/*
* Before packing the attributes, re-order them so that
* the array ones are all contiguous. This simplifies
* the later code.
*/
num_vps = 0;
for (vp = packet->vps; vp != NULL; vp = vp->next) {
num_vps++;
}
if (num_vps > 1) {
VALUE_PAIR **array, **last;
array = malloc(num_vps * sizeof(VALUE_PAIR *));
i = 0;
for (vp = packet->vps; vp != NULL; vp = vp->next) {
array[i++] = vp;
}
/*
* Sort the attributes.
*/
qsort(array, (size_t) num_vps, sizeof(VALUE_PAIR *),
attr_cmp);
last = &packet->vps;
for (i = 0; i < num_vps; i++) {
*last = array[i];
array[i]->next = NULL;
last = &(array[i]->next);
}
free(array);
}
p[0] = 0x35; /* DHCP-Message-Type */
p[1] = 1;
p[2] = packet->code - PW_DHCP_OFFSET;
p += 3;
/*
* Pack in the attributes.
*/
vp = packet->vps;
while (vp) {
int num_entries = 1;
VALUE_PAIR *same;
uint8_t *plength, *pattr;
if (!IS_DHCP_ATTR(vp)) goto next;
if (vp->attribute == DHCP2ATTR(53)) goto next; /* already done */
if (((vp->attribute & 0xffff) > 255) &&
(DHCP_BASE_ATTR(vp->attribute) != PW_DHCP_OPTION_82)) goto next;
length = vp->length;
for (same = vp->next; same != NULL; same = same->next) {
if (same->attribute != vp->attribute) break;
num_entries++;
}
/*
* For client-identifier
*/
if ((vp->type == PW_TYPE_ETHERNET) &&
(vp->length == 6) &&
(num_entries == 1)) {
vp->type = PW_TYPE_OCTETS;
memmove(vp->vp_octets + 1, vp->vp_octets, 6);
vp->vp_octets[0] = 1;
}
pattr = p;
*(p++) = vp->attribute & 0xff;
plength = p;
*(p++) = 0; /* header isn't included in attr length */
for (i = 0; i < num_entries; i++) {
if (fr_debug_flag > 1) {
vp_prints(buffer, sizeof(buffer), vp);
fr_strerror_printf("\t%s", buffer);
}
if (vp->flags.is_tlv) {
VALUE_PAIR *tlv = fr_dhcp_vp2suboption(vp);
if (vp) {
tlv->next = vp->next;
vp->next = tlv;
}
/*
* The encoded flag MUST be set in the vp!
*/
vp = vp->next;
}
length = fr_dhcp_vp2attr(vp, p, 0);
/*
* This will never happen due to FreeRADIUS
* limitations: sizeof(vp->vp_octets) < 255
*/
if (length > 255) {
fr_strerror_printf("WARNING Ignoring too long attribute %s!", vp->name);
break;
}
/*
* More than one attribute of the same type
* in a row: they are packed together
* into the same TLV. If we overflow,
* go bananas!
*/
if ((*plength + length) > 255) {
fr_strerror_printf("WARNING Ignoring too long attribute %s!", vp->name);
break;
}
*plength += length;
p += length;
if (vp->next &&
(vp->next->attribute == vp->attribute))
vp = vp->next;
} /* loop over num_entries */
next:
vp = vp->next;
}
p[0] = 0xff; /* end of option option */
p[1] = 0x00;
p += 2;
dhcp_size = p - packet->data;
/*
* FIXME: if (dhcp_size > mms),
* then we put the extra options into the "sname" and "file"
* fields, AND set the "end option option" in the "options"
* field. We also set the "overload option",
* and put options into the "file" field, followed by
* the "sname" field. Where each option is completely
* enclosed in the "file" and/or "sname" field, AND
* followed by the "end of option", and MUST be followed
* by padding option.
*
* Yuck. That sucks...
*/
packet->data_len = dhcp_size;
if (original) {
/*
* FIXME: This may set it to broadcast, which we don't
* want. Instead, set it to the real address of the
* socket.
*/
packet->src_ipaddr = original->dst_ipaddr;
packet->sockfd = original->sockfd;
}
if (packet->data_len < DEFAULT_PACKET_SIZE) {
memset(packet->data + packet->data_len, 0,
DEFAULT_PACKET_SIZE - packet->data_len);
packet->data_len = DEFAULT_PACKET_SIZE;
}
if ((fr_debug_flag > 2) && fr_log_fp) {
for (i = 0; i < packet->data_len; i++) {
if ((i & 0x0f) == 0x00) fprintf(fr_log_fp, "%d: ", i);
fprintf(fr_log_fp, "%02x ", packet->data[i]);
if ((i & 0x0f) == 0x0f) fprintf(fr_log_fp, "\n");
}
fprintf(fr_log_fp, "\n");
}
return 0;
}
#endif /* WITH_DHCP */
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