/*
- * Copyright (C) 2007-2015 by Internet Systems Consortium, Inc. ("ISC")
+ * Copyright (C) 2007-2016 by Internet Systems Consortium, Inc. ("ISC")
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
}
}
+
+/*
+ * \brief Tests that 16-bit hardware type is less than 256
+ *
+ * XXX: DHCPv6 gives a 16-bit field for the htype. DHCPv4 gives an
+ * 8-bit field. To change the semantics of the generic 'hardware'
+ * structure, we would have to adjust many DHCPv4 sources (from
+ * interface to DHCPv4 lease code), and we would have to update the
+ * 'hardware' config directive (probably being reverse compatible and
+ * providing a new upgrade/replacement primitive). This is a little
+ * too much to change for now. Hopefully we will revisit this before
+ * hardware types exceeding 8 bits are assigned.
+ *
+ * Uses a static variable to limit log occurence to once per startup
+ *
+ * \param htype hardware type value to test
+ *
+ * \return returns 0 if the value is too large
+ *
+*/
+int htype_bounds_check(uint16_t htype) {
+ static int log_once = 0;
+
+ if (htype & 0xFF00) {
+ if (!log_once) {
+ log_error("Attention: At least one client advertises a "
+ "hardware type of %d, which exceeds the software "
+ "limitation of 255.", htype);
+ log_once = 1;
+ }
+
+ return(0);
+ }
+
+ return(1);
+}
+
+/*!
+ * \brief Look for hosts by MAC address if it's available
+ *
+ * Checks the inbound packet against host declarations which specified:
+ *
+ * "hardware ethernet <MAC>;"
+ *
+ * For directly connected clients, the function will use the MAC address
+ * contained in packet:haddr if it's populated. \TODO - While the logic is in
+ * place for this search, the socket layer does not yet populate packet:haddr,
+ * this is to be done under rt41523.
+ *
+ * For relayed clients, the function will use the MAC address from the
+ * client-linklayer-address option if it has been supplied by the relay
+ * directly connected to the client.
+ *
+ * \param hp[out] - pointer to storage for the host delcaration if found
+ * \param packet - received packet
+ * \param opt_state - option state to search
+ * \param file - source file
+ * \param line - line number
+ *
+ * \return non-zero if a matching host was found, zero otherwise
+*/
+int find_hosts_by_haddr6(struct host_decl **hp,
+ struct packet *packet,
+ struct option_state *opt_state,
+ const char *file, int line) {
+ int found = 0;
+ int htype;
+ int hlen;
+
+ /* For directly connected clients, use packet:haddr if populated */
+ if (packet->dhcpv6_container_packet == NULL) {
+ if (packet->haddr) {
+ htype = packet->haddr->hbuf[0];
+ hlen = packet->haddr->hlen - 1,
+ log_debug("find_hosts_by_haddr6: using packet->haddr,"
+ " type: %d, len: %d", htype, hlen);
+ found = find_hosts_by_haddr (hp, htype,
+ &packet->haddr->hbuf[1],
+ hlen, MDL);
+ }
+ } else {
+ /* The first container packet is the from the relay directly
+ * connected to the client. Per RFC 6939, that is only relay
+ * that may supply the client linklayer address option. */
+ struct packet *relay_packet = packet->dhcpv6_container_packet;
+ struct option_state *relay_state = relay_packet->options;
+ struct data_string rel_addr;
+ struct option_cache *oc;
+
+ /* Look for the option in the first relay packet */
+ oc = lookup_option(&dhcpv6_universe, relay_state,
+ D6O_CLIENT_LINKLAYER_ADDR);
+ if (!oc) {
+ /* Not there, so bail */
+ return (0);
+ }
+
+ /* The option is present, fetch the address data */
+ memset(&rel_addr, 0, sizeof(rel_addr));
+ if (!evaluate_option_cache(&rel_addr, relay_packet, NULL, NULL,
+ relay_state, NULL, &global_scope,
+ oc, MDL)) {
+ log_error("find_hosts_by_add6:"
+ "Error evaluating option cache");
+ return (0);
+ }
+
+ /* The relay address data should be:
+ * byte 0 - 1 = hardware type
+ * bytes 2 - hlen = hardware address
+ * where hlen ( hardware address len) is option data len - 2 */
+ hlen = rel_addr.len - 2;
+ if (hlen > 0 && hlen <= HARDWARE_ADDR_LEN) {
+ htype = getUShort(rel_addr.data);
+ if (htype_bounds_check(htype)) {
+ /* Looks valid, let's search with it */
+ log_debug("find_hosts_by_haddr6:"
+ "using relayed haddr"
+ " type: %d, len: %d", htype, hlen);
+ found = find_hosts_by_haddr (hp, htype,
+ &rel_addr.data[2],
+ hlen, MDL);
+ }
+ }
+
+ data_string_forget(&rel_addr, MDL);
+ }
+
+ return (found);
+}
+
+/*
+ * find_host_by_duid_chaddr() synthesizes a DHCPv4-like 'hardware'
+ * parameter from a DHCPv6 supplied DUID (client-identifier option),
+ * and may seek to use client or relay supplied hardware addresses.
+ */
+int
+find_hosts_by_duid_chaddr(struct host_decl **host,
+ const struct data_string *client_id) {
+ int htype, hlen;
+ const unsigned char *chaddr;
+
+ /*
+ * The DUID-LL and DUID-LLT must have a 2-byte DUID type and 2-byte
+ * htype.
+ */
+ if (client_id->len < 4)
+ return 0;
+
+ /*
+ * The third and fourth octets of the DUID-LL and DUID-LLT
+ * is the hardware type, but in 16 bits.
+ */
+ htype = getUShort(client_id->data + 2);
+ hlen = 0;
+ chaddr = NULL;
+
+ /* The first two octets of the DUID identify the type. */
+ switch(getUShort(client_id->data)) {
+ case DUID_LLT:
+ if (client_id->len > 8) {
+ hlen = client_id->len - 8;
+ chaddr = client_id->data + 8;
+ }
+ break;
+
+ case DUID_LL:
+ /*
+ * Note that client_id->len must be greater than or equal
+ * to four to get to this point in the function.
+ */
+ hlen = client_id->len - 4;
+ chaddr = client_id->data + 4;
+ break;
+
+ default:
+ break;
+ }
+
+ if ((hlen == 0) || (hlen > HARDWARE_ADDR_LEN) ||
+ !htype_bounds_check(htype)) {
+ return (0);
+ }
+
+ return find_hosts_by_haddr(host, htype, chaddr, hlen, MDL);
+}
+
+/*
+ * \brief Finds a host record that matches the packet, if any
+ *
+ * This function centralizes the logic for matching v6 client
+ * packets to host declarations. We check in the following order
+ * for matches with:
+ *
+ * 1. client_id if specified
+ * 2. MAC address when explicitly available
+ * 3. packet option
+ * 4. synthesized hardware address - this is done last as some
+ * synthesis methods are not consided to be reliable
+ *
+ * \param[out] host - pointer to storage for the located host
+ * \param packet - inbound client packet
+ * \param client_id - client identifier (if one)
+ * \param file - source file
+ * \param line - source file line number
+ * \return non-zero if a host is found, zero otherwise
+*/
+int
+find_hosts6(struct host_decl** host, struct packet* packet,
+ const struct data_string* client_id, char* file, int line) {
+ return (find_hosts_by_uid(host, client_id->data, client_id->len, MDL)
+ || find_hosts_by_haddr6(host, packet, packet->options, MDL)
+ || find_hosts_by_option(host, packet, packet->options, MDL)
+ || find_hosts_by_duid_chaddr(host, client_id));
+}
+
+
/* unittest moved to server/tests/mdb6_unittest.c */
projects / thirdparty / dhcp.git / blobdiff