/
dhcp.c
1597 lines (1346 loc) · 35.7 KB
/
dhcp.c
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/*
* dhcp.c Functions to send/receive dhcp packets.
*
* Version: $Id$
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; 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>
*/
RCSID("$Id$")
#include <freeradius-devel/libradius.h>
#include <freeradius-devel/udpfromto.h>
#include <freeradius-devel/dhcp.h>
#ifndef __MINGW32__
#include <sys/ioctl.h>
#endif
#ifdef HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#ifndef __MINGW32__
#include <net/if_arp.h>
#endif
#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
/* @todo: this is a hack */
# define DEBUG if (fr_debug_flag && fr_log_fp) fr_printf_log
void fr_strerror_printf(char const *fmt, ...);
# define debug_pair(vp) do { if (fr_debug_flag && fr_log_fp) { \
vp_print(fr_log_fp, vp); \
} \
} while(0)
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 char const *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 char const *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;
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;
ssize_t data_len;
packet = rad_alloc(NULL, 0);
if (!packet) {
fr_strerror_printf("Failed allocating packet");
return NULL;
}
packet->data = talloc_zero_array(packet, uint8_t, MAX_PACKET_SIZE);
if (!packet->data) {
fr_strerror_printf("Out of memory");
rad_free(&packet);
return NULL;
}
packet->sockfd = sockfd;
sizeof_src = sizeof(src);
#ifdef WITH_UDPFROMTO
sizeof_dst = sizeof(dst);
data_len = recvfromto(sockfd, packet->data, MAX_PACKET_SIZE, 0,
(struct sockaddr *)&src, &sizeof_src,
(struct sockaddr *)&dst, &sizeof_dst);
#else
data_len = recvfrom(sockfd, packet->data, MAX_PACKET_SIZE, 0,
(struct sockaddr *)&src, &sizeof_src);
#endif
if (data_len <= 0) {
fr_strerror_printf("Failed reading DHCP socket: %s", fr_syserror(errno));
rad_free(&packet);
return NULL;
}
packet->data_len = data_len;
if (packet->data_len < MIN_PACKET_SIZE) {
fr_strerror_printf("DHCP packet is too small (%zu < %d)",
packet->data_len, MIN_PACKET_SIZE);
rad_free(&packet);
return NULL;
}
if (packet->data_len > MAX_PACKET_SIZE) {
fr_strerror_printf("DHCP packet is too large (%zx > %d)",
packet->data_len, MAX_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...
*/
if (getsockname(sockfd, (struct sockaddr *) &dst, &sizeof_dst) < 0) {
fr_strerror_printf("getsockname failed: %s", fr_syserror(errno));
rad_free(&packet);
return NULL;
}
#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];
char const *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\n",
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;
fr_ipaddr2sockaddr(&packet->src_ipaddr, packet->src_port,
&src, &sizeof_src);
#endif
fr_ipaddr2sockaddr(&packet->dst_ipaddr, packet->dst_port,
&dst, &sizeof_dst);
if (packet->data_len == 0) {
fr_strerror_printf("No data to send");
return -1;
}
if (fr_debug_flag > 1) {
char type_buf[64];
char const *name = type_buf;
#ifdef WITH_UDPFROMTO
char src_ip_buf[INET6_ADDRSTRLEN];
#endif
char dst_ip_buf[INET6_ADDRSTRLEN];
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(
#ifdef WITH_UDPFROMTO
"Sending %s of id %08x from %s:%d to %s:%d\n",
#else
"Sending %s of id %08x to %s:%d\n",
#endif
name, (unsigned int) packet->id,
#ifdef WITH_UDPFROMTO
inet_ntop(packet->src_ipaddr.af, &packet->src_ipaddr.ipaddr, src_ip_buf, sizeof(src_ip_buf)),
packet->src_port,
#endif
inet_ntop(packet->dst_ipaddr.af, &packet->dst_ipaddr.ipaddr, dst_ip_buf, sizeof(dst_ip_buf)),
packet->dst_port);
}
#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
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(RADIUS_PACKET *packet, VALUE_PAIR *vp, uint8_t const *p, size_t alen);
static int decode_tlv(RADIUS_PACKET *packet, VALUE_PAIR *tlv, uint8_t const *data, size_t data_len)
{
uint8_t const *p;
VALUE_PAIR *head, *vp;
vp_cursor_t cursor;
/*
* 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;
paircursor(&cursor, &head);
p = data;
while (p < (data + data_len)) {
vp = paircreate(packet, tlv->da->attr | (p[0] << 8), DHCP_MAGIC_VENDOR);
if (!vp) {
pairfree(&head);
goto make_tlv;
}
if (fr_dhcp_attr2vp(packet, vp, p + 2, p[1]) < 0) {
pairfree(&head);
goto make_tlv;
}
pairinsert(&cursor, vp);
p += 2 + p[1];
}
/*
* The caller allocated TLV, so we need to copy the FIRST
* attribute over top of that.
*
* This is a pretty awful hack, but we should be able to
* clean it up when we get nested VPs so lets leave it for
* now.
*/
if (head) {
/* Cleanup any old TLV data */
talloc_free(tlv->vp_tlv);
/* @fixme fragile */
memcpy(tlv, head, sizeof(*tlv));
/* If the VP has a talloced value we need to reparent it to the original TLV attribute */
switch (head->da->type) {
case PW_TYPE_STRING:
case PW_TYPE_OCTETS:
case PW_TYPE_TLV:
talloc_steal(tlv, head->data.ptr);
default:
break;
}
tlv->next = head->next;
talloc_free(head);
}
return 0;
make_tlv:
tlv->vp_tlv = talloc_array(tlv, uint8_t, 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(RADIUS_PACKET *packet, VALUE_PAIR *vp, uint8_t const *p, size_t alen)
{
char *q;
switch (vp->da->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;
memcpy(&vp->vp_integer, p, 2);
vp->vp_integer = ntohs(vp->vp_integer);
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;
/*
* Keep value in Network Order!
*/
memcpy(&vp->vp_ipaddr, p , 4);
vp->length = 4;
break;
case PW_TYPE_STRING:
vp->vp_strvalue = q = talloc_array(vp, char, alen + 1);
vp->type = VT_DATA;
memcpy(q, p , alen);
q[alen] = '\0';
break;
case PW_TYPE_ETHERNET:
memcpy(vp->vp_ether, p, sizeof(vp->vp_ether));
vp->length = sizeof(vp->vp_ether);
break;
/*
* Value doesn't match up with attribute type, overwrite the
* vp's original DICT_ATTR with an unknown one.
*/
raw:
if (pair2unknown(vp) < 0) return -1;
case PW_TYPE_OCTETS:
if (alen > 253) return -1;
pairmemcpy(vp, p, alen);
break;
case PW_TYPE_TLV:
return decode_tlv(packet, vp, p, alen);
default:
fr_strerror_printf("Internal sanity check %d %d", vp->da->type, __LINE__);
return -1;
} /* switch over type */
vp->length = alen;
return 0;
}
ssize_t fr_dhcp_decode_options(RADIUS_PACKET *packet,
uint8_t const *data, size_t len, VALUE_PAIR **head)
{
int i;
VALUE_PAIR *vp;
vp_cursor_t cursor;
uint8_t const *p, *next;
next = data;
*head = NULL;
paircursor(&cursor, head);
/*
* FIXME: This should also check sname && file fields.
* See the dhcp_get_option() function above.
*/
while (next < (data + len)) {
int num_entries, alen;
DICT_ATTR const *da;
p = next;
if (*p == 0) break;
if (*p == 255) break; /* end of options signifier */
if ((p + 2) > (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(p[0], DHCP_MAGIC_VENDOR);
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(packet, NULL, da->name, NULL, T_OP_ADD);
if (!vp) {
fr_strerror_printf("Cannot build attribute %s",
fr_strerror());
pairfree(head);
return -1;
}
/*
* Hack for ease of use.
*/
if ((da->vendor == DHCP_MAGIC_VENDOR) &&
(da->attr == 61) && !da->flags.array &&
(alen == 7) && (*p == 1) && (num_entries == 1)) {
pairmemcpy(vp, p + 1, 6);
} else if (fr_dhcp_attr2vp(packet, vp, p, alen) < 0) {
pairfree(&vp);
pairfree(head);
return -1;
}
pairinsert(&cursor, vp);
for (vp = paircurrent(&cursor);
vp;
vp = pairnext(&cursor)) {
debug_pair(vp);
}
p += alen;
} /* loop over array entries */
} /* loop over the entire packet */
return next - data;
}
int fr_dhcp_decode(RADIUS_PACKET *packet)
{
size_t i;
uint8_t *p;
uint32_t giaddr;
vp_cursor_t cursor;
VALUE_PAIR *head = NULL, *vp;
VALUE_PAIR *maxms, *mtu;
paircursor(&cursor, &head);
p = packet->data;
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: ", (int) 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++) {
char *q;
vp = pairmake(packet, NULL, dhcp_header_names[i], NULL, T_OP_EQ);
if (!vp) {
char buffer[256];
strlcpy(buffer, fr_strerror(), sizeof(buffer));
fr_strerror_printf("Cannot decode packet due to internal error: %s", buffer);
pairfree(&head);
return -1;
}
/*
* If chaddr does != 6 bytes it's probably not ethernet, and we should store
* it as an opaque type (octets).
*/
if ((i == 11) && (packet->data[1] == 1) && (packet->data[2] != sizeof(vp->vp_ether))) {
DICT_ATTR const *da = dict_attrunknown(vp->da->attr, vp->da->vendor, true);
if (!da) {
return -1;
}
vp->da = da;
}
switch (vp->da->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:
vp->vp_strvalue = q = talloc_array(vp, char, dhcp_header_sizes[i] + 1);
vp->type = VT_DATA;
memcpy(q, p, dhcp_header_sizes[i]);
q[dhcp_header_sizes[i]] = '\0';
vp->length = strlen(vp->vp_strvalue);
if (vp->length == 0) {
pairfree(&vp);
}
break;
case PW_TYPE_OCTETS:
pairmemcpy(vp, p, 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->da->type);
pairfree(&vp);
break;
}
p += dhcp_header_sizes[i];
if (!vp) continue;
debug_pair(vp);
pairinsert(&cursor, vp);
}
/*
* Loop over the options.
*/
/*
* Nothing uses tail after this call, if it does in the future
* it'll need to find the new tail...
*/
{
VALUE_PAIR *options = NULL;
if (fr_dhcp_decode_options(packet,
packet->data + 240, packet->data_len - 240,
&options) < 0) {
return -1;
}
if (options) {
pairinsert(&cursor, options);
}
}
/*
* 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, 256, DHCP_MAGIC_VENDOR, TAG_ANY);
if (vp && vp->vp_integer == 3) {
/*
* Vendor is "MSFT 98"
*/
vp = pairfind(head, 63, DHCP_MAGIC_VENDOR, TAG_ANY);
if (vp && (strcmp(vp->vp_strvalue, "MSFT 98") == 0)) {
vp = pairfind(head, 262, DHCP_MAGIC_VENDOR, TAG_ANY);
/*
* Reply should be broadcast.
*/
if (vp) vp->vp_integer |= 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, 57, DHCP_MAGIC_VENDOR, TAG_ANY);
mtu = pairfind(packet->vps, 26, DHCP_MAGIC_VENDOR, TAG_ANY);
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(void const *one, void const *two)
{
VALUE_PAIR const * const *a = one;
VALUE_PAIR const * const *b = two;
/*
* DHCP-Message-Type is first, for simplicity.
*/
if (((*a)->da->attr == 53) &&
(*b)->da->attr != 53) return -1;
/*
* Relay-Agent is last
*/
if (((*a)->da->attr == 82) &&
(*b)->da->attr != 82) return 1;
return ((*a)->da->attr - (*b)->da->attr);
}
/*
* @todo Check room!
*/
static size_t fr_dhcp_vp2attr(VALUE_PAIR *vp, uint8_t *p, UNUSED size_t room)
{
size_t length;
uint32_t lvalue;
/*
* Search for all attributes of the same
* type, and pack them into the same
* attribute.
*/
switch (vp->da->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);