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-rw-r--r--src/modules/proto_dhcp/dhcp.c2268
1 files changed, 2268 insertions, 0 deletions
diff --git a/src/modules/proto_dhcp/dhcp.c b/src/modules/proto_dhcp/dhcp.c
new file mode 100644
index 0000000..f922d63
--- /dev/null
+++ b/src/modules/proto_dhcp/dhcp.c
@@ -0,0 +1,2268 @@
+/*
+ * 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>
+#include <freeradius-devel/net.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_lvl && fr_log_fp) fr_printf_log
+# define debug_pair(vp) do { if (fr_debug_lvl && fr_log_fp) { \
+ vp_print(fr_log_fp, vp); \
+ } \
+ } while(0)
+
+#ifdef HAVE_LINUX_IF_PACKET_H
+#define ETH_HDR_SIZE 14
+#define IP_HDR_SIZE 20
+#define UDP_HDR_SIZE 8
+#define ETH_ADDR_LEN 6
+#define ETH_TYPE_IP 0x0800
+#define ETH_P_ALL 0x0003
+
+static uint8_t eth_bcast[ETH_ADDR_LEN] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
+
+/* Discard raw packets which we are not interested in. Allow to trace why we discard. */
+#define DISCARD_RP(...) { \
+ if (fr_debug_lvl > 2) { \
+ fprintf(stdout, "dhcpclient: discarding received packet: "); \
+ fprintf(stdout, ## __VA_ARGS__); \
+ fprintf(stdout, "\n"); \
+ } \
+ rad_free(&packet); \
+ return NULL; \
+}
+#endif
+
+#define VENDORPEC_ADSL 3561
+
+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",
+ "DHCP-Lease-Query",
+ "DHCP-Lease-Unassigned",
+ "DHCP-Lease-Unknown",
+ "DHCP-Lease-Active",
+ "DHCP-Bulk-Lease-Query",
+ "DHCP-Lease-Query-Done"
+};
+
+#define DHCP_MAX_MESSAGE_TYPE (sizeof(dhcp_message_types) / sizeof(dhcp_message_types[0]))
+
+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;
+ uint16_t port;
+ uint8_t *code;
+ ssize_t data_len;
+
+ packet = rad_alloc(NULL, false);
+ 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] != 0) && (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, PW_DHCP_MESSAGE_TYPE);
+ 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] >= DHCP_MAX_MESSAGE_TYPE)) {
+ fr_strerror_printf("Unknown value %d for message-type option", code[2]);
+ rad_free(&packet);
+ return NULL;
+ }
+
+ packet->code = code[2] | PW_DHCP_OFFSET;
+
+ /*
+ * Create a unique vector from the xid and the client
+ * hardware address. This is a hack for the RADIUS
+ * infrastructure in the rest of the server.
+ * It is also used for de-duplicating DHCP packets
+ */
+ memcpy(packet->vector, packet->data + 4, 4); /* xid */
+ memcpy(packet->vector + 4, packet->data + 24, 4); /* giaddr */
+ packet->vector[8] = packet->code & 0xff; /* message type */
+ memcpy(packet->vector + 9, packet->data + 28, 6); /* chaddr is always 6 for us */
+
+ /*
+ * FIXME: for DISCOVER / REQUEST: src_port == dst_port + 1
+ * FIXME: for OFFER / ACK : src_port = dst_port - 1
+ */
+
+ 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_lvl > 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 < (1024 + DHCP_MAX_MESSAGE_TYPE))) {
+ 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_lvl > 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 < (1024 + DHCP_MAX_MESSAGE_TYPE))) {
+ 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 Id %08x from %s:%d to %s:%d\n",
+#else
+ "Sending %s 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(TALLOC_CTX *ctx, VALUE_PAIR **vp_p, uint8_t const *p, size_t alen);
+
+/** Returns the number of array members for arrays with fixed element sizes
+ *
+ */
+static int fr_dhcp_array_members(size_t *len, DICT_ATTR const *da)
+{
+ int num_entries = 1;
+
+ if (!len || !da) return -1;
+
+ /*
+ * Could be an array of bytes, integers, etc.
+ */
+ if (da->flags.array) switch (da->type) {
+ case PW_TYPE_BYTE:
+ num_entries = *len;
+ *len = 1;
+ break;
+
+ case PW_TYPE_SHORT: /* ignore any trailing data */
+ num_entries = *len >> 1;
+ *len = 2;
+ break;
+
+ case PW_TYPE_IPV4_ADDR:
+ case PW_TYPE_INTEGER:
+ case PW_TYPE_DATE: /* ignore any trailing data */
+ num_entries = *len >> 2;
+ *len = 4;
+ break;
+
+ case PW_TYPE_IPV6_ADDR:
+ num_entries = *len >> 4;
+ *len = 16;
+ break;
+
+ default:
+ break;
+ }
+
+ return num_entries;
+}
+
+/** RFC 4243 Vendor Specific Suboptions
+ *
+ * Vendor specific suboptions are in the format.
+ @verbatim
+ 0 1 2 3
+ 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ | Enterprise Number 0 |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ | Len 0 | /
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ / Suboption Data 0 /
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ | Enterprise Number n |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ | Len n | /
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ / Suboption Data n /
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ @endverbatim
+ *
+ * So although the vendor is identified, the format of the data isn't
+ * specified so we can't actually resolve the suboption to an
+ * attribute. For now, we just convert it to an attribute of
+ * DHCP-Vendor-Specific-Information with raw octets contents.
+ */
+
+
+/** Decode DHCP suboptions
+ *
+ * @param[in,out] tlv to decode. *tlv will be set to the head of the list of suboptions and original will be freed.
+ * @param[in] ctx context to alloc new attributes in.
+ * @param[in] data to parse.
+ * @param[in] len length of data to parse.
+ */
+static int fr_dhcp_decode_suboption(TALLOC_CTX *ctx, VALUE_PAIR **tlv, uint8_t const *data, size_t len)
+{
+ uint8_t const *p, *q;
+ VALUE_PAIR *head, *vp;
+ vp_cursor_t cursor;
+
+ /*
+ * TLV must already point to a VALUE_PAIR.
+ */
+ VERIFY_VP(*tlv);
+
+ /*
+ * Take a pass at parsing it.
+ */
+ p = data;
+ q = data + len;
+ while (p < q) {
+ /*
+ * RFC 3046 is very specific about not allowing termination
+ * with a 255 sub-option. But it's required for decoding
+ * option 43, and vendors will probably screw it up
+ * anyway.
+ */
+ if (*p == 0) {
+ p++;
+ continue;
+ }
+ if (*p == 255) {
+ q--;
+ break;
+ }
+
+ /*
+ * Check if reading length would take us past the end of the buffer
+ */
+ if (++p >= q) goto malformed;
+ p += p[0];
+
+ /*
+ * Check if length > the length of the buffer we have left
+ */
+ if (p >= q) goto malformed;
+ p++;
+ }
+
+ /*
+ * Got here... must be well formed.
+ */
+ head = NULL;
+ fr_cursor_init(&cursor, &head);
+
+ p = data;
+ while (p < q) {
+ uint8_t const *a_p;
+ size_t a_len;
+ int num_entries, i;
+
+ DICT_ATTR const *da;
+ uint32_t attr;
+
+ /*
+ * Not enough room for the option header, it's a
+ * bad packet.
+ */
+ if ((p + 2) > (data + len)) {
+ fr_pair_list_free(&head);
+ return -1;
+ }
+
+ /*
+ * Not enough room for the option header + data,
+ * it's a bad packet.
+ */
+ if ((p + 2 + p[1]) > (data + len)) {
+ fr_pair_list_free(&head);
+ return -1;
+ }
+
+ /*
+ * The initial OID string looks like:
+ * <iana>.0
+ *
+ * If <iana>.0 is type TLV then we attempt to decode its contents as more
+ * DHCP suboptions, which gives us:
+ * <iana>.<attr>
+ *
+ * If <iana>.0 is not defined in the dictionary or is type octets, we leave
+ * the attribute as is.
+ */
+ attr = (*tlv)->da->attr ? ((*tlv)->da->attr | (p[0] << 8)) : p[0];
+
+ /*
+ * Use the vendor of the parent TLV which is not necessarily
+ * DHCP_MAGIC_VENDOR.
+ *
+ * Note: This does not deal with dictionary numbering clashes. If
+ * the vendor uses different numbers for DHCP suboptions and RADIUS
+ * attributes then it's time to break out %{hex:} and regular
+ * expressions.
+ */
+ da = dict_attrbyvalue(attr, (*tlv)->da->vendor);
+ if (!da) {
+ da = dict_unknown_afrom_fields(ctx, attr, (*tlv)->da->vendor);
+ if (!da) {
+ fr_pair_list_free(&head);
+ return -1;
+ }
+ }
+
+ a_len = p[1];
+ a_p = p + 2;
+ num_entries = fr_dhcp_array_members(&a_len, da);
+ for (i = 0; i < num_entries; i++) {
+ vp = fr_pair_afrom_da(ctx, da);
+ if (!vp) {
+ fr_pair_list_free(&head);
+ return -1;
+ }
+ vp->op = T_OP_EQ;
+ fr_pair_steal(ctx, vp); /* for unknown attributes hack */
+
+ if (fr_dhcp_attr2vp(ctx, &vp, a_p, a_len) < 0) {
+ dict_attr_free(&da);
+ fr_pair_list_free(&head);
+ goto malformed;
+ }
+ fr_cursor_merge(&cursor, vp);
+
+ a_p += a_len;
+ }
+
+ dict_attr_free(&da); /* for unknown attributes hack */
+
+ p += 2 + p[1]; /* code (1) + len (1) + suboption len (n)*/
+ }
+
+ /*
+ * The caller allocated a TLV, if decoding it generated
+ * additional attributes, we now need to free it, and write
+ * the HEAD of our new list of attributes in its place.
+ */
+ if (head) {
+ vp_cursor_t tlv_cursor;
+
+ /*
+ * Free the old TLV attribute
+ */
+ TALLOC_FREE(*tlv);
+
+ /*
+ * Cursor not necessary but means we don't have to set
+ * ->next directly.
+ */
+ fr_cursor_init(&tlv_cursor, tlv);
+ fr_cursor_merge(&tlv_cursor, head);
+ }
+
+ return 0;
+
+malformed:
+ fr_pair_to_unknown(*tlv);
+ fr_pair_value_memcpy(*tlv, data, len);
+
+ return 0;
+}
+
+/*
+ * Decode ONE value into a VP
+ */
+static int fr_dhcp_attr2vp(TALLOC_CTX *ctx, VALUE_PAIR **vp_p, uint8_t const *data, size_t len)
+{
+ VALUE_PAIR *vp = *vp_p;
+ VERIFY_VP(vp);
+
+ switch (vp->da->type) {
+ case PW_TYPE_BYTE:
+ if (len != 1) goto raw;
+ vp->vp_byte = data[0];
+ break;
+
+ case PW_TYPE_SHORT:
+ if (len != 2) goto raw;
+ memcpy(&vp->vp_short, data, 2);
+ vp->vp_short = ntohs(vp->vp_short);
+ break;
+
+ case PW_TYPE_INTEGER:
+ if (len != 4) goto raw;
+ memcpy(&vp->vp_integer, data, 4);
+ vp->vp_integer = ntohl(vp->vp_integer);
+ break;
+
+ case PW_TYPE_IPV4_ADDR:
+ if (len != 4) goto raw;
+ /*
+ * Keep value in Network Order!
+ */
+ memcpy(&vp->vp_ipaddr, data, 4);
+ vp->vp_length = 4;
+ break;
+
+ /*
+ * In DHCPv4, string options which can also be arrays,
+ * have their values '\0' delimited.
+ */
+ case PW_TYPE_STRING:
+ {
+ uint8_t const *p;
+ uint8_t const *q, *end;
+ vp_cursor_t cursor;
+
+ p = data;
+ q = end = data + len;
+
+ if (!vp->da->flags.array) {
+ fr_pair_value_bstrncpy(vp, (char const *)p, q - p);
+ break;
+ }
+
+ /*
+ * Initialise the cursor as we may be inserting
+ * multiple additional VPs
+ */
+ fr_cursor_init(&cursor, vp_p);
+ while (p < end) {
+ q = memchr(p, '\0', end - p);
+ /* Malformed but recoverable */
+ if (!q) q = end;
+
+ fr_pair_value_bstrncpy(vp, (char const *)p, q - p);
+ p = q + 1;
+
+ if (p >= end) break;
+
+ /* Need another VP for the next round */
+ vp = fr_pair_afrom_da(ctx, vp->da);
+ if (!vp) {
+ fr_pair_list_free(vp_p);
+ return -1;
+ }
+ fr_cursor_insert(&cursor, vp);
+ }
+ }
+ break;
+
+ case PW_TYPE_ETHERNET:
+ memcpy(vp->vp_ether, data, sizeof(vp->vp_ether));
+ vp->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 (fr_pair_to_unknown(vp) < 0) return -1;
+ /* FALL-THROUGH */
+
+ case PW_TYPE_OCTETS:
+ if (len > 255) return -1;
+ fr_pair_value_memcpy(vp, data, len);
+ break;
+
+ /*
+ * For option 82 et al...
+ */
+ case PW_TYPE_TLV:
+ return fr_dhcp_decode_suboption(ctx, vp_p, data, len);
+
+ default:
+ fr_strerror_printf("Internal sanity check %d %d", vp->da->type, __LINE__);
+ return -1;
+ } /* switch over type */
+
+ vp->vp_length = len;
+ return 0;
+}
+
+/** Decode DHCP options
+ *
+ * @param[in,out] out Where to write the decoded options.
+ * @param[in] ctx context to alloc new attributes in.
+ * @param[in] data to parse.
+ * @param[in] len of data to parse.
+ */
+ssize_t fr_dhcp_decode_options(TALLOC_CTX *ctx, VALUE_PAIR **out, uint8_t const *data, size_t len)
+{
+ VALUE_PAIR *vp;
+ vp_cursor_t cursor;
+ uint8_t const *p, *q;
+
+ *out = NULL;
+ fr_cursor_init(&cursor, out);
+
+ /*
+ * FIXME: This should also check sname && file fields.
+ * See the dhcp_get_option() function above.
+ */
+ p = data;
+ q = data + len;
+ while (p < q) {
+ uint8_t const *a_p;
+ size_t a_len;
+ int num_entries, i;
+
+ DICT_ATTR const *da;
+
+ if (*p == 0) { /* 0x00 - Padding option */
+ p++;
+ continue;
+ }
+
+ if (*p == 255) { /* 0xff - End of options signifier */
+ break;
+ }
+
+ if ((p + 2) > q) break;
+
+ a_len = p[1];
+ a_p = p + 2;
+
+ /*
+ * Ensure we've not been given a bad length value
+ */
+ if ((a_p + a_len) > q) {
+ fr_strerror_printf("Length field value of option %u is incorrect. "
+ "Got %u bytes, expected <= %zu bytes", p[0], p[1], q - a_p);
+ fr_pair_list_free(out);
+ return -1;
+ }
+
+ /*
+ * Unknown attribute, create an octets type
+ * attribute with the contents of the sub-option.
+ */
+ da = dict_attrbyvalue(p[0], DHCP_MAGIC_VENDOR);
+ if (!da) {
+ da = dict_unknown_afrom_fields(ctx, p[0], DHCP_MAGIC_VENDOR);
+ if (!da) {
+ fr_pair_list_free(out);
+ return -1;
+ }
+ vp = fr_pair_afrom_da(ctx, da);
+ if (!vp) {
+ fr_pair_list_free(out);
+ return -1;
+ }
+ fr_pair_value_memcpy(vp, a_p, a_len);
+ fr_cursor_insert(&cursor, vp);
+
+ goto next;
+ }
+
+ /*
+ * Decode ADSL Forum vendor-specific options.
+ */
+ if ((p[0] == 125) && (p[1] > 6) && (p[2] == 0) && (p[3] == 0) && (p[4] == 0x0d) && (p[5] == 0xe9) &&
+ (p[6] + 5 == p[1])) {
+ da = dict_attrbyvalue(255, VENDORPEC_ADSL);
+ if (!da) goto normal;
+
+ vp = fr_pair_afrom_da(ctx, da);
+ if (!vp) {
+ fr_pair_list_free(out);
+ return -1;
+ }
+
+ (void) fr_dhcp_decode_suboption(ctx, &vp, p + 7, p[6]);
+ if (vp) fr_cursor_merge(&cursor, vp);
+ goto next;
+ }
+
+ normal:
+ /*
+ * Array type sub-option create a new VALUE_PAIR
+ * for each array element.
+ */
+ num_entries = fr_dhcp_array_members(&a_len, da);
+ for (i = 0; i < num_entries; i++) {
+ vp = fr_pair_afrom_da(ctx, da);
+ if (!vp) {
+ fr_pair_list_free(out);
+ return -1;
+ }
+ vp->op = T_OP_EQ;
+
+ if (fr_dhcp_attr2vp(ctx, &vp, a_p, a_len) < 0) {
+ fr_pair_list_free(&vp);
+ fr_pair_list_free(out);
+ return -1;
+ }
+ fr_cursor_merge(&cursor, vp);
+ a_p += a_len;
+ } /* loop over array entries */
+ next:
+ p += 2 + p[1]; /* code (1) + len (1) + option len (n)*/
+ } /* loop over the entire packet */
+
+ return p - 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, *netaddr;
+
+ fr_cursor_init(&cursor, &head);
+ p = packet->data;
+
+ if ((fr_debug_lvl > 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++) {
+
+ vp = fr_pair_afrom_num(packet, 256 + i, DHCP_MAGIC_VENDOR);
+ if (!vp) {
+ char buffer[256];
+ strlcpy(buffer, fr_strerror(), sizeof(buffer));
+ fr_strerror_printf("Cannot decode packet due to internal error: %s", buffer);
+ fr_pair_list_free(&head);
+ return -1;
+ }
+
+ /*
+ * If chaddr != 6 bytes it's probably not ethernet, and we should store
+ * it as an opaque type (octets).
+ */
+ if (i == 11) {
+ /*
+ * Skip chaddr if it doesn't exist.
+ */
+ if ((packet->data[1] == 0) || (packet->data[2] == 0)) continue;
+
+ if ((packet->data[1] == 1) && (packet->data[2] != sizeof(vp->vp_ether))) {
+ DICT_ATTR const *da = dict_unknown_afrom_fields(packet, vp->da->attr, vp->da->vendor);
+ if (!da) {
+ return -1;
+ }
+ vp->da = da;
+ }
+ }
+
+ switch (vp->da->type) {
+ case PW_TYPE_BYTE:
+ vp->vp_byte = p[0];
+ vp->vp_length = 1;
+ break;
+
+ case PW_TYPE_SHORT:
+ vp->vp_short = (p[0] << 8) | p[1];
+ vp->vp_length = 2;
+ break;
+
+ case PW_TYPE_INTEGER:
+ memcpy(&vp->vp_integer, p, 4);
+ vp->vp_integer = ntohl(vp->vp_integer);
+ vp->vp_length = 4;
+ break;
+
+ case PW_TYPE_IPV4_ADDR:
+ memcpy(&vp->vp_ipaddr, p, 4);
+ vp->vp_length = 4;
+ break;
+
+ case PW_TYPE_STRING:
+ /*
+ * According to RFC 2131, these are null terminated strings.
+ * We don't trust everyone to abide by the RFC, though.
+ */
+ if (*p != '\0') {
+ uint8_t *end;
+ int len;
+ end = memchr(p, '\0', dhcp_header_sizes[i]);
+ len = end ? end - p : dhcp_header_sizes[i];
+ fr_pair_value_bstrncpy(vp, p, len);
+ }
+ if (vp->vp_length == 0) fr_pair_list_free(&vp);
+ break;
+
+ case PW_TYPE_OCTETS:
+ if (packet->data[2] == 0) break;
+
+ fr_pair_value_memcpy(vp, p, packet->data[2]);
+ break;
+
+ case PW_TYPE_ETHERNET:
+ memcpy(vp->vp_ether, p, sizeof(vp->vp_ether));
+ vp->vp_length = sizeof(vp->vp_ether);
+ break;
+
+ default:
+ fr_strerror_printf("BAD TYPE %d", vp->da->type);
+ fr_pair_list_free(&vp);
+ break;
+ }
+ p += dhcp_header_sizes[i];
+
+ if (!vp) continue;
+
+ debug_pair(vp);
+ fr_cursor_insert(&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;
+ vp_cursor_t options_cursor;
+
+ if (fr_dhcp_decode_options(packet, &options, packet->data + 240, packet->data_len - 240) < 0) {
+ return -1;
+ }
+
+ if (options) {
+ for (vp = fr_cursor_init(&options_cursor, &options);
+ vp;
+ vp = fr_cursor_next(&options_cursor)) {
+ debug_pair(vp);
+ }
+ fr_cursor_merge(&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-Message-Type is request
+ */
+ vp = fr_pair_find_by_num(head, 53, DHCP_MAGIC_VENDOR, TAG_ANY);
+ if (vp && vp->vp_byte == 3) {
+ /*
+ * Vendor is "MSFT 98"
+ */
+ vp = fr_pair_find_by_num(head, 60, DHCP_MAGIC_VENDOR, TAG_ANY);
+ if (vp && (vp->vp_length >= 7) && (memcmp(vp->vp_octets, "MSFT 98", 7) == 0)) {
+ vp = fr_pair_find_by_num(head, 262, DHCP_MAGIC_VENDOR, TAG_ANY);
+
+ /*
+ * Reply should be broadcast.
+ */
+ if (vp) vp->vp_short |= 0x8000;
+ packet->data[10] |= 0x80;
+ }
+ }
+ }
+
+ /*
+ * Determine the address to use in looking up which subnet the
+ * client belongs to based on packet data. The sequence here
+ * is based on ISC DHCP behaviour and RFCs 3527 and 3011. We
+ * store the found address in an internal attribute of 274 -
+ * DHCP-Network-Subnet. This is stored as an IPv4 prefix
+ * with a /32 netmask allowing "closest containing subnet"
+ * matching in rlm_files
+ */
+ vp = fr_pair_afrom_num(packet, 274, DHCP_MAGIC_VENDOR);
+ /*
+ * First look for Relay-Link-Selection - option 82, suboption 5
+ */
+ netaddr = fr_pair_find_by_num(head, (82 | (5 << 8)), DHCP_MAGIC_VENDOR, TAG_ANY);
+ if (!netaddr) {
+ /*
+ * Next try Subnet-Selection-Option - option 118
+ */
+ netaddr = fr_pair_find_by_num(head, 118, DHCP_MAGIC_VENDOR, TAG_ANY);
+ }
+ if (!netaddr) {
+ if (giaddr != htonl(INADDR_ANY)) {
+ /*
+ * Gateway address is set - use that one
+ */
+ memcpy(&vp->vp_ipv4prefix[2], packet->data + 24, 4);
+ } else {
+ /*
+ * else, store client address whatever it is
+ */
+ memcpy(&vp->vp_ipv4prefix[2], packet->data + 12, 4);
+ }
+ } else {
+ /*
+ * Store whichever address we've found from options
+ */
+ memcpy(&vp->vp_ipv4prefix[2], &netaddr->vp_ipaddr, 4);
+ }
+ /*
+ * Set the netmask to /32
+ */
+ vp->vp_ipv4prefix[0] = 0;
+ vp->vp_ipv4prefix[1] = 32;
+
+ debug_pair(vp);
+ fr_cursor_insert(&cursor, vp);
+
+ /*
+ * 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 = fr_pair_find_by_num(packet->vps, 57, DHCP_MAGIC_VENDOR, TAG_ANY);
+ mtu = fr_pair_find_by_num(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_lvl) fflush(stdout);
+
+ return 0;
+}
+
+
+int8_t fr_dhcp_attr_cmp(void const *a, void const *b)
+{
+ VALUE_PAIR const *my_a = a;
+ VALUE_PAIR const *my_b = b;
+
+ VERIFY_VP(my_a);
+ VERIFY_VP(my_b);
+
+ /*
+ * ADSL Forum vendor-specific options after others to remain grouped
+ */
+ if ((my_a->da->vendor == VENDORPEC_ADSL) && (my_b->da->vendor != VENDORPEC_ADSL)) return +1;
+ if ((my_a->da->vendor != VENDORPEC_ADSL) && (my_b->da->vendor == VENDORPEC_ADSL)) return -1;
+
+ /*
+ * DHCP-Message-Type is first, for simplicity.
+ */
+ if ((my_a->da->attr == PW_DHCP_MESSAGE_TYPE) && (my_b->da->attr != PW_DHCP_MESSAGE_TYPE)) return -1;
+ if ((my_a->da->attr != PW_DHCP_MESSAGE_TYPE) && (my_b->da->attr == PW_DHCP_MESSAGE_TYPE)) return +1;
+
+ /*
+ * Relay-Agent is last
+ */
+ if ((my_a->da->attr == PW_DHCP_OPTION_82) && (my_b->da->attr != PW_DHCP_OPTION_82)) return +1;
+ if ((my_a->da->attr != PW_DHCP_OPTION_82) && (my_b->da->attr == PW_DHCP_OPTION_82)) return -1;
+
+ if (my_a->da->attr < my_b->da->attr) return -1;
+ if (my_a->da->attr > my_b->da->attr) return 1;
+
+ return 0;
+}
+
+/** Write DHCP option value into buffer
+ *
+ * Does not include DHCP option length or number.
+ *
+ * @param out where to write the DHCP option.
+ * @param outlen length of output buffer.
+ * @param vp option to encode.
+ * @return the length of data writen, -1 if out of buffer, -2 if unsupported type.
+ */
+static ssize_t fr_dhcp_vp2data(uint8_t *out, size_t outlen, VALUE_PAIR *vp)
+{
+ uint32_t lvalue;
+ uint8_t *p = out;
+
+ if (outlen < vp->vp_length) {
+ return -1;
+ }
+
+ switch (vp->da->type) {
+ case PW_TYPE_BYTE:
+ *p = vp->vp_byte;
+ break;
+
+ case PW_TYPE_SHORT:
+ p[0] = (vp->vp_short >> 8) & 0xff;
+ p[1] = vp->vp_short & 0xff;
+ break;
+
+ case PW_TYPE_INTEGER:
+ lvalue = htonl(vp->vp_integer);
+ memcpy(p, &lvalue, 4);
+ break;
+
+ case PW_TYPE_IPV4_ADDR:
+ memcpy(p, &vp->vp_ipaddr, 4);
+ break;
+
+ case PW_TYPE_ETHERNET:
+ memcpy(p, vp->vp_ether, 6);
+ break;
+
+ case PW_TYPE_STRING:
+ memcpy(p, vp->vp_strvalue, vp->vp_length);
+ break;
+
+ case PW_TYPE_OCTETS:
+ memcpy(p, vp->vp_octets, vp->vp_length);
+ break;
+
+ default:
+ fr_strerror_printf("Unsupported option type %d", vp->da->type);
+ return -2;
+ }
+
+ return vp->vp_length;
+}
+
+/** Create a new TLV attribute from multiple sub options
+ *
+ * @param[in,out] out buffer to write the data
+ * @param[out] outlen length of the output buffer
+ * @param[in,out] cursor should be set to the start of the list of TLV attributes.
+ * Will be advanced to the first non-TLV attribute.
+ * @return length of data encoded, or -1 on error
+ */
+static ssize_t fr_dhcp_vp2data_tlv(uint8_t *out, ssize_t outlen, vp_cursor_t *cursor)
+{
+ ssize_t len;
+ unsigned int parent; /* Parent attribute of suboption */
+ uint8_t attr = 0;
+ uint8_t *p, *opt_len;
+ vp_cursor_t tlv_cursor;
+ VALUE_PAIR *vp;
+
+#define SUBOPTION_PARENT(_x) (_x & 0xffff00ff)
+#define SUBOPTION_ATTR(_x) ((_x & 0xff00) >> 8)
+
+ vp = fr_cursor_current(cursor);
+ if (!vp) return -1;
+
+ parent = SUBOPTION_PARENT(vp->da->attr);
+
+ /*
+ * Remember where we started off.
+ */
+ fr_cursor_copy(&tlv_cursor, cursor);
+
+ /*
+ * Loop over TLVs to determine how much memory we need to allocate
+ *
+ * We advanced the tlv_cursor we were passed, so if we
+ * fail encoding, the tlv_cursor is at the right position
+ * for the next potentially encodable attr.
+ */
+ len = 0;
+ for (vp = fr_cursor_current(&tlv_cursor);
+ vp && vp->da->flags.is_tlv && (SUBOPTION_PARENT(vp->da->attr) == parent);
+ vp = fr_cursor_next(&tlv_cursor)) {
+ if (SUBOPTION_ATTR(vp->da->attr) == 0) {
+ fr_strerror_printf("Invalid attribute number 0");
+ return -1;
+ }
+
+ /*
+ * If it's not an array type or is an array type,
+ * but is not the same as the previous attribute,
+ * we add 2 for the additional sub-option header
+ * bytes.
+ */
+ if (!vp->da->flags.array || (SUBOPTION_ATTR(vp->da->attr) != attr)) {
+ attr = SUBOPTION_ATTR(vp->da->attr);
+ len += 2;
+ }
+ len += vp->vp_length;
+ }
+
+ if (len > outlen) {
+ fr_strerror_printf("Insufficient room for suboption");
+ return -1;
+ }
+
+ attr = 0;
+ opt_len = NULL;
+ p = out;
+
+ for (vp = fr_cursor_current(cursor);
+ vp && vp->da->flags.is_tlv && (SUBOPTION_PARENT(vp->da->attr) == parent);
+ vp = fr_cursor_next(cursor)) {
+ /* Don't write out the header, were packing array options */
+ if (!opt_len || !vp->da->flags.array || (attr != SUBOPTION_ATTR(vp->da->attr))) {
+ attr = SUBOPTION_ATTR(vp->da->attr);
+ *p++ = attr;
+ opt_len = p++;
+ *opt_len = 0;
+ }
+
+ len = fr_dhcp_vp2data(p, out + outlen - p, vp);
+ if ((len < 0) || (len > 255)) {
+ return -1;
+ }
+
+ debug_pair(vp);
+ *opt_len += len;
+ p += len;
+ };
+
+ return p - out;
+}
+
+static ssize_t fr_dhcp_encode_adsl(uint8_t *out, size_t outlen, vp_cursor_t *cursor)
+{
+ VALUE_PAIR *vp;
+ uint8_t *p;
+ size_t room;
+
+ if (outlen <= (2 + 4 + 1)) return -1;
+
+ out[0] = 125; /* Vendor-Specific */
+ out[1] = 5; /* vendorpec + 1 octet of length */
+ out[2] = 0;
+ out[3] = 0;
+ out[4] = 0x0d;
+ out[5] = 0xe9; /* ADSL forum vendorpec */
+ out[6] = 0; /* vendor-specific length */
+
+ p = out + 7;
+ room = outlen - 7;
+
+ for (vp = fr_cursor_current(cursor);
+ ((vp != NULL) && (vp->da->vendor == VENDORPEC_ADSL) &&
+ (vp->da->attr > 255) && ((vp->da->attr & 0xff) == 0xff));
+ vp = fr_cursor_next(cursor)) {
+ ssize_t length;
+
+ /*
+ * Silently discard options when there isn't enough room.
+ */
+ if (room < 2) break;
+
+ p[0] = (vp->da->attr >> 8) & 0xff;
+
+ length = fr_dhcp_vp2data(p + 2, room - 2, vp);
+ if (length < 0) break; /* not enough room */
+ if (length > 255) break; /* too much data */
+
+ p[1] = length;
+
+ length += 2; /* include the attribute header */
+
+ /*
+ * We don't (yet) split Vendor-Specific. So if
+ * there's too much data, just discard the extra
+ * data.
+ */
+ if ((out[1] + length) > 255) break;
+
+ out[1] += length;
+ out[6] += length;
+ p += length;
+ room -= length;
+ }
+
+ /*
+ * Don't encode options with no data.
+ */
+ if (out[1] == 5) return 0;
+
+ return out[1] + 2;
+}
+
+/** Encode a DHCP option and any sub-options.
+ *
+ * @param out Where to write encoded DHCP attributes.
+ * @param outlen Length of out buffer.
+ * @param ctx to use for any allocated memory.
+ * @param cursor with current VP set to the option to be encoded. Will be advanced to the next option to encode.
+ * @return > 0 length of data written, < 0 error, 0 not valid option (skipping).
+ */
+ssize_t fr_dhcp_encode_option(UNUSED TALLOC_CTX *ctx, uint8_t *out, size_t outlen, vp_cursor_t *cursor)
+{
+ VALUE_PAIR *vp;
+ DICT_ATTR const *previous;
+ uint8_t *opt_len, *p = out;
+ size_t freespace = outlen;
+ ssize_t len;
+
+ vp = fr_cursor_current(cursor);
+ if (!vp) return -1;
+
+ if (vp->da->vendor != DHCP_MAGIC_VENDOR) {
+ if ((vp->da->vendor == VENDORPEC_ADSL) &&
+ (vp->da->attr > 255) && ((vp->da->attr & 0xff) == 0xff)) {
+ return fr_dhcp_encode_adsl(out, outlen, cursor);
+ }
+ goto next; /* not a DHCP option */
+ }
+ if (vp->da->attr == PW_DHCP_MESSAGE_TYPE) goto next; /* already done */
+ if ((vp->da->attr > 255) && (DHCP_BASE_ATTR(vp->da->attr) != PW_DHCP_OPTION_82)) goto next;
+
+ if (vp->da->flags.extended) {
+ next:
+ fr_strerror_printf("Attribute \"%s\" is not a DHCP option", vp->da->name);
+ fr_cursor_next(cursor);
+ return 0;
+ }
+
+ /* Write out the option number */
+ *(p++) = vp->da->attr & 0xff;
+
+ /* Pointer to the length field of the option */
+ opt_len = p++;
+
+ /* Zero out the option's length field */
+ *opt_len = 0;
+
+ /* We just consumed two bytes for the header */
+ freespace -= 2;
+
+ /* DHCP options with the same number get coalesced into a single option */
+ do {
+ /*
+ * Sub-option encoder will encode the data and
+ * advance the cursor.
+ */
+ if (vp->da->flags.is_tlv) {
+ len = fr_dhcp_vp2data_tlv(p, freespace, cursor);
+ previous = NULL;
+
+ } else {
+ len = fr_dhcp_vp2data(p, freespace, vp);
+ if (len >= 0) debug_pair(vp);
+ fr_cursor_next(cursor);
+ previous = vp->da;
+ }
+
+ if (len < 0) return len;
+
+ if ((*opt_len + len) > 255) {
+ fr_strerror_printf("Skipping \"%s\": Option splitting not supported "
+ "(option > 255 bytes)", vp->da->name);
+ return 0;
+ }
+
+ p += len;
+ *opt_len += len;
+ freespace -= len;
+
+ } while ((vp = fr_cursor_current(cursor)) && previous && (previous == vp->da) && vp->da->flags.array);
+
+ return p - out;
+}
+
+int fr_dhcp_encode(RADIUS_PACKET *packet)
+{
+ unsigned int i;
+ uint8_t *p;
+ vp_cursor_t cursor;
+ VALUE_PAIR *vp;
+ uint32_t lvalue;
+ uint16_t svalue;
+ size_t dhcp_size;
+ ssize_t len;
+#ifndef NDEBUG
+ char const *name;
+# ifdef WITH_UDPFROMTO
+ char src_ip_buf[256];
+# endif
+ char dst_ip_buf[256];
+#endif
+
+ if (packet->data) return 0;
+
+ packet->data_len = MAX_PACKET_SIZE;
+ packet->data = talloc_zero_array(packet, uint8_t, packet->data_len);
+
+ /* XXX Ugly ... should be set by the caller */
+ if (packet->code == 0) packet->code = PW_DHCP_NAK;
+
+ /* store xid */
+ if ((vp = fr_pair_find_by_num(packet->vps, 260, DHCP_MAGIC_VENDOR, TAG_ANY))) {
+ packet->id = vp->vp_integer;
+ } else {
+ packet->id = fr_rand();
+ }
+
+#ifndef NDEBUG
+ if ((packet->code >= PW_DHCP_DISCOVER) &&
+ (packet->code < (1024 + DHCP_MAX_MESSAGE_TYPE))) {
+ name = dhcp_message_types[packet->code - PW_DHCP_OFFSET];
+ } else {
+ name = "?Unknown?";
+ }
+
+ DEBUG(
+# ifdef WITH_UDPFROMTO
+ "Encoding %s of id %08x from %s:%d to %s:%d\n",
+# else
+ "Encoding %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);
+#endif
+
+ p = packet->data;
+
+ /*
+ * @todo: Make this work again.
+ */
+#if 0
+ mms = DEFAULT_PACKET_SIZE; /* maximum message size */
+
+ /*
+ * Clients can request a LARGER size, but not a
+ * smaller one. They also cannot request a size
+ * larger than MTU.
+ */
+
+ /* DHCP-DHCP-Maximum-Msg-Size */
+ vp = fr_pair_find_by_num(packet->vps, 57, DHCP_MAGIC_VENDOR, TAG_ANY);
+ if (vp && (vp->vp_integer > mms)) {
+ mms = vp->vp_integer;
+
+ if (mms > MAX_PACKET_SIZE) mms = MAX_PACKET_SIZE;
+ }
+#endif
+
+ vp = fr_pair_find_by_num(packet->vps, 256, DHCP_MAGIC_VENDOR, TAG_ANY);
+ if (vp) {
+ *p++ = vp->vp_integer & 0xff;
+ } else {
+ *p++ = 1; /* client message */
+ }
+
+ /* DHCP-Hardware-Type */
+ if ((vp = fr_pair_find_by_num(packet->vps, 257, DHCP_MAGIC_VENDOR, TAG_ANY))) {
+ *p++ = vp->vp_byte;
+ } else {
+ *p++ = 1; /* hardware type = ethernet */
+ }
+
+ /* DHCP-Hardware-Address-Length */
+ if ((vp = fr_pair_find_by_num(packet->vps, 258, DHCP_MAGIC_VENDOR, TAG_ANY))) {
+ *p++ = vp->vp_byte;
+ } else {
+ *p++ = 6; /* 6 bytes of ethernet */
+ }
+
+ /* DHCP-Hop-Count */
+ if ((vp = fr_pair_find_by_num(packet->vps, 259, DHCP_MAGIC_VENDOR, TAG_ANY))) {
+ *p = vp->vp_byte;
+ }
+ p++;
+
+ /* DHCP-Transaction-Id */
+ lvalue = htonl(packet->id);
+ memcpy(p, &lvalue, 4);
+ p += 4;
+
+ /* DHCP-Number-of-Seconds */
+ if ((vp = fr_pair_find_by_num(packet->vps, 261, DHCP_MAGIC_VENDOR, TAG_ANY))) {
+ svalue = htons(vp->vp_short);
+ memcpy(p, &svalue, 2);
+ }
+ p += 2;
+
+ /* DHCP-Flags */
+ if ((vp = fr_pair_find_by_num(packet->vps, 262, DHCP_MAGIC_VENDOR, TAG_ANY))) {
+ svalue = htons(vp->vp_short);
+ memcpy(p, &svalue, 2);
+ }
+ p += 2;
+
+ /* DHCP-Client-IP-Address */
+ if ((vp = fr_pair_find_by_num(packet->vps, 263, DHCP_MAGIC_VENDOR, TAG_ANY))) {
+ memcpy(p, &vp->vp_ipaddr, 4);
+ }
+ p += 4;
+
+ /* DHCP-Your-IP-address */
+ if ((vp = fr_pair_find_by_num(packet->vps, 264, DHCP_MAGIC_VENDOR, TAG_ANY))) {
+ lvalue = vp->vp_ipaddr;
+ } else {
+ lvalue = htonl(INADDR_ANY);
+ }
+ memcpy(p, &lvalue, 4);
+ p += 4;
+
+ /* DHCP-Server-IP-Address */
+ vp = fr_pair_find_by_num(packet->vps, 265, DHCP_MAGIC_VENDOR, TAG_ANY);
+ if (vp) {
+ lvalue = vp->vp_ipaddr;
+ } else {
+ lvalue = htonl(INADDR_ANY);
+ }
+ memcpy(p, &lvalue, 4);
+ p += 4;
+
+ /*
+ * DHCP-Gateway-IP-Address
+ */
+ if ((vp = fr_pair_find_by_num(packet->vps, 266, DHCP_MAGIC_VENDOR, TAG_ANY))) {
+ lvalue = vp->vp_ipaddr;
+ } else {
+ lvalue = htonl(INADDR_ANY);
+ }
+ memcpy(p, &lvalue, 4);
+ p += 4;
+
+ /* DHCP-Client-Hardware-Address */
+ if ((vp = fr_pair_find_by_num(packet->vps, 267, DHCP_MAGIC_VENDOR, TAG_ANY))) {
+ if (vp->vp_length == sizeof(vp->vp_ether)) {
+ /*
+ * Ensure that we mark the packet as being Ethernet.
+ * This is mainly for DHCP-Lease-Query responses.
+ */
+ packet->data[1] = 1;
+ packet->data[2] = 6;
+
+ memcpy(p, vp->vp_ether, vp->vp_length);
+ } /* else ignore it */
+ }
+ p += DHCP_CHADDR_LEN;
+
+ /* DHCP-Server-Host-Name */
+ if ((vp = fr_pair_find_by_num(packet->vps, 268, DHCP_MAGIC_VENDOR, TAG_ANY))) {
+ if (vp->vp_length > DHCP_SNAME_LEN) {
+ memcpy(p, vp->vp_strvalue, DHCP_SNAME_LEN);
+ } else {
+ memcpy(p, vp->vp_strvalue, vp->vp_length);
+ }
+ }
+ p += DHCP_SNAME_LEN;
+
+ /*
+ * Copy over DHCP-Boot-Filename.
+ *
+ * FIXME: This copy should be delayed until AFTER the options
+ * have been processed. If there are too many options for
+ * the packet, then they go into the sname && filename fields.
+ * When that happens, the boot filename is passed as an option,
+ * instead of being placed verbatim in the filename field.
+ */
+
+ /* DHCP-Boot-Filename */
+ vp = fr_pair_find_by_num(packet->vps, 269, DHCP_MAGIC_VENDOR, TAG_ANY);
+ if (vp) {
+ if (vp->vp_length > DHCP_FILE_LEN) {
+ memcpy(p, vp->vp_strvalue, DHCP_FILE_LEN);
+ } else {
+ memcpy(p, vp->vp_strvalue, vp->vp_length);
+ }
+ }
+ p += DHCP_FILE_LEN;
+
+ /* DHCP magic number */
+ lvalue = htonl(DHCP_OPTION_MAGIC_NUMBER);
+ memcpy(p, &lvalue, 4);
+ p += 4;
+
+ /*
+ * Print the header.
+ */
+ if (fr_debug_lvl > 1) {
+ uint8_t *pp = p;
+
+ p = packet->data;
+
+ for (i = 0; i < 14; i++) {
+ char *q;
+
+ vp = fr_pair_make(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);
+ return -1;
+ }
+
+ switch (vp->da->type) {
+ case PW_TYPE_BYTE:
+ vp->vp_byte = p[0];
+ break;
+
+ case PW_TYPE_SHORT:
+ vp->vp_short = (p[0] << 8) | p[1];
+ break;
+
+ case PW_TYPE_INTEGER:
+ memcpy(&vp->vp_integer, p, 4);
+ vp->vp_integer = ntohl(vp->vp_integer);
+ break;
+
+ case PW_TYPE_IPV4_ADDR:
+ memcpy(&vp->vp_ipaddr, p, 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->vp_length = strlen(vp->vp_strvalue);
+ break;
+
+ case PW_TYPE_OCTETS: /* only for Client HW Address */
+ fr_pair_value_memcpy(vp, p, packet->data[2]);
+ break;
+
+ case PW_TYPE_ETHERNET: /* only for Client HW Address */
+ memcpy(vp->vp_ether, p, sizeof(vp->vp_ether));
+ break;
+
+ default:
+ fr_strerror_printf("Internal sanity check failed %d %d", vp->da->type, __LINE__);
+ fr_pair_list_free(&vp);
+ break;
+ }
+
+ p += dhcp_header_sizes[i];
+
+ debug_pair(vp);
+ fr_pair_list_free(&vp);
+ }
+
+ /*
+ * Jump over DHCP magic number, response, etc.
+ */
+ p = pp;
+ }
+
+ p[0] = 0x35; /* DHCP-Message-Type */
+ p[1] = 1;
+ p[2] = packet->code - PW_DHCP_OFFSET;
+ p += 3;
+
+ /*
+ * Pre-sort attributes into contiguous blocks so that fr_dhcp_encode_option
+ * operates correctly. This changes the order of the list, but never mind...
+ */
+ fr_pair_list_sort(&packet->vps, fr_dhcp_attr_cmp);
+ fr_cursor_init(&cursor, &packet->vps);
+
+ /*
+ * Each call to fr_dhcp_encode_option will encode one complete DHCP option,
+ * and sub options.
+ */
+ while ((vp = fr_cursor_current(&cursor))) {
+ len = fr_dhcp_encode_option(packet, p, packet->data_len - (p - packet->data), &cursor);
+ if (len < 0) break;
+ p += len;
+ };
+
+ 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 (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_lvl > 2) && fr_log_fp) {
+ fprintf(fr_log_fp, "DHCP Sending %zu bytes\n", packet->data_len);
+ 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");
+ }
+
+ return 0;
+}
+
+#ifdef SIOCSARP
+int fr_dhcp_add_arp_entry(int fd, char const *interface,
+ VALUE_PAIR *macaddr, VALUE_PAIR *ip)
+{
+ struct sockaddr_in *sin;
+ struct arpreq req;
+
+ if (!interface) {
+ fr_strerror_printf("No interface specified. Cannot update ARP table");
+ return -1;
+ }
+
+ if (!fr_assert(macaddr) ||
+ !fr_assert((macaddr->da->type == PW_TYPE_ETHERNET) || (macaddr->da->type == PW_TYPE_OCTETS))) {
+ fr_strerror_printf("Wrong VP type (%s) for chaddr",
+ fr_int2str(dict_attr_types, macaddr->da->type, "<invalid>"));
+ return -1;
+ }
+
+ if (macaddr->vp_length > sizeof(req.arp_ha.sa_data)) {
+ fr_strerror_printf("arp sa_data field too small (%zu octets) to contain chaddr (%zu octets)",
+ sizeof(req.arp_ha.sa_data), macaddr->vp_length);
+ return -1;
+ }
+
+ memset(&req, 0, sizeof(req));
+ sin = (struct sockaddr_in *) &req.arp_pa;
+ sin->sin_family = AF_INET;
+ sin->sin_addr.s_addr = ip->vp_ipaddr;
+
+ strlcpy(req.arp_dev, interface, sizeof(req.arp_dev));
+
+ if (macaddr->da->type == PW_TYPE_ETHERNET) {
+ memcpy(&req.arp_ha.sa_data, macaddr->vp_ether, sizeof(macaddr->vp_ether));
+ } else {
+ memcpy(&req.arp_ha.sa_data, macaddr->vp_octets, macaddr->vp_length);
+ }
+
+ req.arp_flags = ATF_COM;
+ if (ioctl(fd, SIOCSARP, &req) < 0) {
+ fr_strerror_printf("Failed to add entry in ARP cache: %s (%d)", fr_syserror(errno), errno);
+ return -1;
+ }
+
+ return 0;
+}
+#else
+int fr_dhcp_add_arp_entry(UNUSED int fd, UNUSED char const *interface,
+ UNUSED VALUE_PAIR *macaddr, UNUSED VALUE_PAIR *ip)
+{
+ fr_strerror_printf("Adding ARP entry is unsupported on this system");
+ return -1;
+}
+#endif
+
+
+#ifdef HAVE_LINUX_IF_PACKET_H
+/*
+ * Open a packet interface raw socket.
+ * Bind it to the specified interface using a device independent physical layer address.
+ */
+int fr_socket_packet(int iface_index, struct sockaddr_ll *p_ll)
+{
+ int lsockfd;
+
+ /* PF_PACKET - packet interface on device level.
+ using a raw socket allows packet data to be unchanged by the device driver.
+ */
+ lsockfd = socket(PF_PACKET, SOCK_RAW, htons(ETH_P_ALL));
+ if (lsockfd < 0) {
+ fr_strerror_printf("cannot open socket: %s", fr_syserror(errno));
+ return lsockfd;
+ }
+
+ /* Set link layer parameters */
+ memset(p_ll, 0, sizeof(struct sockaddr_ll));
+
+ p_ll->sll_family = AF_PACKET;
+ p_ll->sll_protocol = htons(ETH_P_ALL);
+ p_ll->sll_ifindex = iface_index;
+ p_ll->sll_hatype = ARPHRD_ETHER;
+ p_ll->sll_pkttype = PACKET_OTHERHOST;
+ p_ll->sll_halen = 6;
+
+ if (bind(lsockfd, (struct sockaddr *)p_ll, sizeof(struct sockaddr_ll)) < 0) {
+ close(lsockfd);
+ fr_strerror_printf("cannot bind raw socket: %s", fr_syserror(errno));
+ return -1;
+ }
+
+ return lsockfd;
+}
+
+/*
+ * Encode and send a DHCP packet on a raw packet socket.
+ */
+int fr_dhcp_send_raw_packet(int sockfd, struct sockaddr_ll *p_ll, RADIUS_PACKET *packet)
+{
+ VALUE_PAIR *vp;
+ u_char dhcp_packet[1518] = { 0 };
+
+ /* set ethernet source address to our MAC address (DHCP-Client-Hardware-Address). */
+ u_char dhmac[ETH_ADDR_LEN] = { 0 };
+ if ((vp = fr_pair_find_by_num(packet->vps, 267, DHCP_MAGIC_VENDOR, TAG_ANY))) {
+ if (vp->length == sizeof(vp->vp_ether)) {
+ memcpy(dhmac, vp->vp_ether, vp->length);
+ }
+ }
+
+ /* fill in Ethernet layer (L2) */
+ struct ethernet_header *ethhdr = (struct ethernet_header *)dhcp_packet;
+ memcpy(ethhdr->ether_dst, eth_bcast, ETH_ADDR_LEN);
+ memcpy(ethhdr->ether_src, dhmac, ETH_ADDR_LEN);
+ ethhdr->ether_type = htons(ETH_TYPE_IP);
+
+ /* fill in IP layer (L3) */
+ struct ip_header *iph = (struct ip_header *)(dhcp_packet + ETH_HDR_SIZE);
+ iph->ip_vhl = IP_VHL(4, 5);
+ iph->ip_tos = 0;
+ iph->ip_len = htons(IP_HDR_SIZE + UDP_HDR_SIZE + packet->data_len);
+ iph->ip_id = 0;
+ iph->ip_off = 0;
+ iph->ip_ttl = 64;
+ iph->ip_p = 17;
+ iph->ip_sum = 0; /* Filled later */
+
+ /* saddr: Packet-Src-IP-Address (default: 0.0.0.0). */
+ iph->ip_src.s_addr = packet->src_ipaddr.ipaddr.ip4addr.s_addr;
+
+ /* daddr: packet destination IP addr (should be 255.255.255.255 for broadcast). */
+ iph->ip_dst.s_addr = packet->dst_ipaddr.ipaddr.ip4addr.s_addr;
+
+ /* IP header checksum */
+ iph->ip_sum = fr_iph_checksum((uint8_t const *)iph, 5);
+
+ /* fill in UDP layer (L4) */
+ udp_header_t *uh = (udp_header_t *) (dhcp_packet + ETH_HDR_SIZE + IP_HDR_SIZE);
+
+ uh->src = htons(68);
+ uh->dst = htons(67);
+ u_int16_t l4_len = (UDP_HDR_SIZE + packet->data_len);
+ uh->len = htons(l4_len);
+ uh->checksum = 0; /* UDP checksum will be done after dhcp header */
+
+ /* DHCP layer (L7) */
+ dhcp_packet_t *dhpointer = (dhcp_packet_t *)(dhcp_packet + ETH_HDR_SIZE + IP_HDR_SIZE + UDP_HDR_SIZE);
+ /* just copy what FreeRADIUS has encoded for us. */
+ memcpy(dhpointer, packet->data, packet->data_len);
+
+ /* UDP checksum is done here */
+ uh->checksum = fr_udp_checksum((uint8_t const *)(dhcp_packet + ETH_HDR_SIZE + IP_HDR_SIZE), ntohs(uh->len), uh->checksum,
+ packet->src_ipaddr.ipaddr.ip4addr, packet->dst_ipaddr.ipaddr.ip4addr);
+
+ if (fr_debug_lvl > 1) {
+ char type_buf[64];
+ char const *name = type_buf;
+ char src_ip_buf[INET6_ADDRSTRLEN];
+ char dst_ip_buf[INET6_ADDRSTRLEN];
+
+ if ((packet->code >= PW_DHCP_DISCOVER) &&
+ (packet->code < (1024 + DHCP_MAX_MESSAGE_TYPE))) {
+ 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 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 sendto(sockfd, dhcp_packet,
+ (ETH_HDR_SIZE + IP_HDR_SIZE + UDP_HDR_SIZE + packet->data_len),
+ 0, (struct sockaddr *) p_ll, sizeof(struct sockaddr_ll));
+}
+
+/*
+ * print an ethernet address in a buffer
+ */
+static char * ether_addr_print(const uint8_t *addr, char *buf)
+{
+ sprintf (buf, "%02x:%02x:%02x:%02x:%02x:%02x",
+ addr[0], addr[1], addr[2], addr[3], addr[4], addr[5]);
+ return buf;
+}
+
+/*
+ * For a client, receive a DHCP packet from a raw packet
+ * socket. Make sure it matches the ongoing request.
+ *
+ * FIXME: split this into two, recv_raw_packet, and verify(packet, original)
+ */
+RADIUS_PACKET *fr_dhcp_recv_raw_packet(int sockfd, struct sockaddr_ll *p_ll, RADIUS_PACKET *request)
+{
+ VALUE_PAIR *vp;
+ RADIUS_PACKET *packet;
+ uint8_t *code;
+ uint32_t magic, xid;
+ ssize_t data_len;
+
+ uint8_t *raw_packet;
+ ethernet_header_t *eth_hdr;
+ struct ip_header *ip_hdr;
+ udp_header_t *udp_hdr;
+ dhcp_packet_t *dhcp_hdr;
+ uint16_t udp_src_port;
+ uint16_t udp_dst_port;
+ size_t dhcp_data_len;
+ socklen_t sock_len;
+
+ packet = rad_alloc(NULL, false);
+ if (!packet) {
+ fr_strerror_printf("Failed allocating packet");
+ return NULL;
+ }
+
+ raw_packet = talloc_zero_array(packet, uint8_t, MAX_PACKET_SIZE);
+ if (!raw_packet) {
+ fr_strerror_printf("Out of memory");
+ rad_free(&packet);
+ return NULL;
+ }
+
+ packet->sockfd = sockfd;
+
+ /* a packet was received (but maybe it is not for us) */
+ sock_len = sizeof(struct sockaddr_ll);
+ data_len = recvfrom(sockfd, raw_packet, MAX_PACKET_SIZE, 0,
+ (struct sockaddr *)p_ll, &sock_len);
+
+ uint8_t data_offset = ETH_HDR_SIZE + IP_HDR_SIZE + UDP_HDR_SIZE; // DHCP data starts after Ethernet, IP, UDP.
+
+ if (data_len <= data_offset) DISCARD_RP("Payload (%d) smaller than required for layers 2+3+4", (int)data_len);
+
+ /* map raw packet to packet header of the different layers (Ethernet, IP, UDP) */
+ eth_hdr = (ethernet_header_t *)raw_packet;
+
+ /* a. Check Ethernet layer data (L2) */
+ if (ntohs(eth_hdr->ether_type) != ETH_TYPE_IP) DISCARD_RP("Ethernet type (%d) != IP", ntohs(eth_hdr->ether_type));
+
+ /* If Ethernet destination is not broadcast (ff:ff:ff:ff:ff:ff)
+ * Check if it matches the source HW address used (DHCP-Client-Hardware-Address = 267)
+ */
+ if ( (memcmp(&eth_bcast, &eth_hdr->ether_dst, ETH_ADDR_LEN) != 0) &&
+ (vp = fr_pair_find_by_num(request->vps, 267, DHCP_MAGIC_VENDOR, TAG_ANY)) &&
+ (vp->length == sizeof(vp->vp_ether)) &&
+ (memcmp(vp->vp_ether, &eth_hdr->ether_dst, ETH_ADDR_LEN) != 0) ) {
+ /* No match. */
+ char eth_dest[17+1];
+ char eth_req_src[17+1];
+ DISCARD_RP("Ethernet destination (%s) is not broadcast and doesn't match request source (%s)",
+ ether_addr_print(eth_hdr->ether_dst, eth_dest),
+ ether_addr_print(vp->vp_ether, eth_req_src));
+ }
+
+ /*
+ * Ethernet is OK. Now look at IP.
+ */
+ ip_hdr = (struct ip_header *)(raw_packet + ETH_HDR_SIZE);
+
+ /* b. Check IPv4 layer data (L3) */
+ if (ip_hdr->ip_p != IPPROTO_UDP) DISCARD_RP("IP protocol (%d) != UDP", ip_hdr->ip_p);
+
+ /*
+ * note: checking the destination IP address is not
+ * useful (it would be the offered IP address - which we
+ * don't know beforehand, or the broadcast address).
+ */
+
+ /*
+ * Now check UDP.
+ */
+ udp_hdr = (udp_header_t *)(raw_packet + ETH_HDR_SIZE + IP_HDR_SIZE);
+
+ /* c. Check UDP layer data (L4) */
+ udp_src_port = ntohs(udp_hdr->src);
+ udp_dst_port = ntohs(udp_hdr->dst);
+
+ /*
+ * A DHCP server will always respond to port 68 (to a
+ * client) or 67 (to a relay). Just check that both
+ * ports are 67 or 68.
+ */
+ if (udp_src_port != 67 && udp_src_port != 68) DISCARD_RP("UDP src port (%d) != DHCP (67 or 68)", udp_src_port);
+ if (udp_dst_port != 67 && udp_dst_port != 68) DISCARD_RP("UDP dst port (%d) != DHCP (67 or 68)", udp_dst_port);
+
+ /* d. Check DHCP layer data */
+ dhcp_data_len = data_len - data_offset;
+
+ if (dhcp_data_len < MIN_PACKET_SIZE) DISCARD_RP("DHCP packet is too small (%zu < %d)", dhcp_data_len, MIN_PACKET_SIZE);
+ if (dhcp_data_len > MAX_PACKET_SIZE) DISCARD_RP("DHCP packet is too large (%zu > %d)", dhcp_data_len, MAX_PACKET_SIZE);
+
+ dhcp_hdr = (dhcp_packet_t *)(raw_packet + ETH_HDR_SIZE + IP_HDR_SIZE + UDP_HDR_SIZE);
+
+ if (dhcp_hdr->htype != 1) DISCARD_RP("DHCP hardware type (%d) != Ethernet (1)", dhcp_hdr->htype);
+ if (dhcp_hdr->hlen != 6) DISCARD_RP("DHCP hardware address length (%d) != 6", dhcp_hdr->hlen);
+
+ magic = ntohl(dhcp_hdr->option_format);
+
+ if (magic != DHCP_OPTION_MAGIC_NUMBER) DISCARD_RP("DHCP magic cookie (0x%04x) != DHCP (0x%04x)", magic, DHCP_OPTION_MAGIC_NUMBER);
+
+ /*
+ * Reply transaction id must match value from request.
+ */
+ xid = ntohl(dhcp_hdr->xid);
+ if (xid != (uint32_t)request->id) DISCARD_RP("DHCP transaction ID (0x%04x) != xid from request (0x%04x)", xid, request->id)
+
+ /* all checks ok! this is a DHCP reply we're interested in. */
+ packet->data_len = dhcp_data_len;
+ packet->data = talloc_memdup(packet, raw_packet + data_offset, dhcp_data_len);
+ TALLOC_FREE(raw_packet);
+ packet->id = xid;
+
+ code = dhcp_get_option((dhcp_packet_t *) packet->data,
+ packet->data_len, PW_DHCP_MESSAGE_TYPE);
+ 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 xid and the client
+ * hardware address. This is a hack for the RADIUS
+ * infrastructure in the rest of the server.
+ * It is also used for de-duplicating DHCP packets
+ */
+ memcpy(packet->vector, packet->data + 4, 4); /* xid */
+ memcpy(packet->vector + 4, packet->data + 24, 4); /* giaddr */
+ packet->vector[8] = packet->code & 0xff; /* message type */
+ memcpy(packet->vector + 9, packet->data + 28, 6); /* chaddr is always 6 for us */
+
+ packet->src_port = udp_src_port;
+ packet->dst_port = udp_dst_port;
+
+ packet->src_ipaddr.af = AF_INET;
+ packet->src_ipaddr.ipaddr.ip4addr.s_addr = ip_hdr->ip_src.s_addr;
+ packet->dst_ipaddr.af = AF_INET;
+ packet->dst_ipaddr.ipaddr.ip4addr.s_addr = ip_hdr->ip_dst.s_addr;
+
+ if (fr_debug_lvl > 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 < (1024 + DHCP_MAX_MESSAGE_TYPE))) {
+ 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;
+}
+#endif
generated by cgit v1.2.3 (git 2.39.1) at 2024-05-18 18:21:28 +0000