proto_bfd.c

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/*
 *   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
 */
 
/**
 * $Id: 4c394e4251781396e7de9c865f7a2f1ac933915e $
 * @file proto_bfd.c
 * @brief RADIUS master protocol handler.
 *
 * @copyright 2017 Arran Cudbard-Bell (a.cudbardb@freeradius.org)
 * @copyright 2016 Alan DeKok (aland@freeradius.org)
 */
#include <freeradius-devel/io/listen.h>
#include <freeradius-devel/server/module_rlm.h>
#include <freeradius-devel/internal/internal.h>
 
#include "proto_bfd.h"
 
extern fr_app_t proto_bfd;
 
static int transport_parse(TALLOC_CTX *ctx, void *out, UNUSED void *parent, CONF_ITEM *ci, conf_parser_t const *rule);
static int auth_type_parse(TALLOC_CTX *ctx, void *out, UNUSED void *parent, CONF_ITEM *ci, conf_parser_t const *rule);
 
/** How to parse a BFD listen section
 *
 */
static conf_parser_t const proto_bfd_config[] = {
        { FR_CONF_OFFSET_TYPE_FLAGS("transport", FR_TYPE_VOID, 0, proto_bfd_t, io.submodule),
          .func = transport_parse },
 
        CONF_PARSER_TERMINATOR
};
 
static const conf_parser_t peer_config[] = {
        { FR_CONF_OFFSET("min_transmit_interval", bfd_session_t, desired_min_tx_interval ) },
        { FR_CONF_OFFSET("min_receive_interval", bfd_session_t, required_min_rx_interval ) },
        { FR_CONF_OFFSET("max_timeouts", bfd_session_t, detect_multi ) },
        { FR_CONF_OFFSET("demand", bfd_session_t, demand_mode ) },
 
        { FR_CONF_OFFSET_TYPE_FLAGS("auth_type", FR_TYPE_VOID, 0, bfd_session_t, auth_type ),
        .func = auth_type_parse },
 
        { FR_CONF_OFFSET("port", bfd_session_t, port ) },
 
        CONF_PARSER_TERMINATOR
};
 
static fr_dict_t const *dict_bfd;
 
extern fr_dict_autoload_t proto_bfd_dict[];
fr_dict_autoload_t proto_bfd_dict[] = {
        { .out = &dict_bfd, .proto = "bfd" },
        { NULL }
};
 
static fr_dict_attr_t const *attr_packet_type;
static fr_dict_attr_t const *attr_bfd_packet;
static fr_dict_attr_t const *attr_my_discriminator;
static fr_dict_attr_t const *attr_your_discriminator;
static fr_dict_attr_t const *attr_additional_data;
 
extern fr_dict_attr_autoload_t proto_bfd_dict_attr[];
fr_dict_attr_autoload_t proto_bfd_dict_attr[] = {
        { .out = &attr_packet_type, .name = "Packet-Type", .type = FR_TYPE_UINT32, .dict = &dict_bfd},
 
        { .out = &attr_bfd_packet, .name = "Packet", .type = FR_TYPE_STRUCT, .dict = &dict_bfd},
        { .out = &attr_my_discriminator, .name = "Packet.my-discriminator", .type = FR_TYPE_UINT32, .dict = &dict_bfd},
        { .out = &attr_your_discriminator, .name = "Packet.your-discriminator", .type = FR_TYPE_UINT32, .dict = &dict_bfd},
 
        { .out = &attr_additional_data, .name = "Additional-Data", .type = FR_TYPE_GROUP, .dict = &dict_bfd},
        { NULL }
};
 
/*
 *      They all have to be UDP.
 */
static int8_t client_cmp(void const *one, void const *two)
{
        fr_client_t const *a = one;
        fr_client_t const *b = two;
 
        return fr_ipaddr_cmp(&a->ipaddr, &b->ipaddr);
}
 
/** Wrapper around dl_instance
 *
 * @param[in] ctx       to allocate data in (instance of proto_bfd).
 * @param[out] out      Where to write a dl_module_inst_t containing the module handle and instance.
 * @param[in] parent    Base structure address.
 * @param[in] ci        #CONF_PAIR specifying the name of the type module.
 * @param[in] rule      unused.
 * @return
 *      - 0 on success.
 *      - -1 on failure.
 */
static int transport_parse(TALLOC_CTX *ctx, void *out, UNUSED void *parent, CONF_ITEM *ci, UNUSED conf_parser_t const *rule)
{
        char const              *name = cf_pair_value(cf_item_to_pair(ci));
        dl_module_inst_t        *parent_inst;
        proto_bfd_t             *inst;
        CONF_SECTION            *listen_cs = cf_item_to_section(cf_parent(ci));
        CONF_SECTION            *transport_cs;
        dl_module_inst_t        *dl_mod_inst;
 
        transport_cs = cf_section_find(listen_cs, name, NULL);
 
        parent_inst = cf_data_value(cf_data_find(listen_cs, dl_module_inst_t, "proto_bfd"));
        fr_assert(parent_inst);
 
        /*
         *      Set the allowed codes so that we can compile them as
         *      necessary.
         */
        inst = talloc_get_type_abort(parent_inst->data, proto_bfd_t);
        inst->io.transport = name;
 
        /*
         *      Allocate an empty section if one doesn't exist
         *      this is so defaults get parsed.
         */
        if (!transport_cs) {
                transport_cs = cf_section_alloc(listen_cs, listen_cs, name, NULL);
                inst->io.app_io_conf = transport_cs;
        }
 
        if (dl_module_instance(ctx, &dl_mod_inst, parent_inst,
                               DL_MODULE_TYPE_SUBMODULE, name, dl_module_inst_name_from_conf(transport_cs)) < 0) return -1;
        if (dl_module_conf_parse(dl_mod_inst, transport_cs) < 0) {
                talloc_free(dl_mod_inst);
                return -1;
        }
        *((dl_module_inst_t **)out) = dl_mod_inst;
 
        return 0;
}
 
/** Parse auth_type
 *
 * @param[in] ctx       to allocate data in (instance of proto_bfd).
 * @param[out] out      Where to write the auth_type value
 * @param[in] parent    Base structure address.
 * @param[in] ci        #CONF_PAIR specifying the name of the type module.
 * @param[in] rule      unused.
 * @return
 *      - 0 on success.
 *      - -1 on failure.
 */
static int auth_type_parse(UNUSED TALLOC_CTX *ctx, void *out, UNUSED void *parent, CONF_ITEM *ci, UNUSED conf_parser_t const *rule)
{
        char const              *name = cf_pair_value(cf_item_to_pair(ci));
        int                     auth_type;
 
        auth_type = fr_table_value_by_str(bfd_auth_type_table, name, -1);
        if (auth_type < 0) {
                cf_log_err(ci, "Invalid value for 'auth_type'");
                return -1;
        }
 
        *(bfd_auth_type_t *) out = auth_type;
 
        return 0;
}
 
 
/** Decode the packet
 *
 */
static int mod_decode(UNUSED void const *instance, request_t *request, uint8_t *const data, size_t data_len)
{
        fr_io_track_t const     *track = talloc_get_type_abort_const(request->async->packet_ctx, fr_io_track_t);
        fr_io_address_t const   *address = track->address;
        fr_client_t const       *client;
        fr_pair_t               *vp, *reply, *my, *your;
        bfd_wrapper_t const     *wrapper = (bfd_wrapper_t const *) data;
        bfd_packet_t const      *bfd = (bfd_packet_t const *) wrapper->packet;
 
        /*
         *      Set the request dictionary so that we can do
         *      generic->protocol attribute conversions as
         *      the request runs through the server.
         */
        request->dict = dict_bfd;
 
        client = address->radclient;
 
        /*
         *      Hacks for now until we have a lower-level decode routine.
         */
        request->packet->code = bfd->state;
        request->packet->id = fr_nbo_to_uint32((uint8_t const *) &bfd->my_disc);
        request->reply->id = request->packet->id;
 
        request->packet->data = talloc_memdup(request->packet, data, data_len);
        request->packet->data_len = data_len;
 
        /*
         *      Set the rest of the fields.
         */
        request->client = UNCONST(fr_client_t *, client);
 
        request->packet->socket = address->socket;
        fr_socket_addr_swap(&request->reply->socket, &address->socket);
 
        REQUEST_VERIFY(request);
 
        /*
         *      Decode the packet into the reply.
         */
        if (wrapper->type == BFD_WRAPPER_SEND_PACKET) {
                if (fr_bfd_decode(request->reply_ctx, &request->reply_pairs,
                                  (uint8_t const *) bfd, bfd->length,
                                  client->secret, talloc_array_length(client->secret) - 1) < 0) {
                        RPEDEBUG("Failed decoding packet");
                        return -1;
                }
 
                request->reply->code = bfd->state;
 
                return 0;
        }
 
        if (fr_bfd_decode(request->request_ctx, &request->request_pairs,
                          (uint8_t const *) bfd, bfd->length,
                          client->secret, talloc_array_length(client->secret) - 1) < 0) {
                RPEDEBUG("Failed decoding packet");
                return -1;
        }
 
        /*
         *      Initialize the reply.
         */
        vp = fr_pair_find_by_da(&request->request_pairs, NULL, attr_bfd_packet);
        if (!vp) return -1;
 
        reply = fr_pair_copy(request->reply_ctx, vp);
        fr_pair_append(&request->reply_pairs, reply);
 
        my = fr_pair_find_by_da_nested(&reply->vp_group, NULL, attr_my_discriminator);
        your = fr_pair_find_by_da_nested(&reply->vp_group, NULL, attr_your_discriminator);
 
        if (my && your) {
                uint32_t tmp = your->vp_uint32;
 
                your->vp_uint32 = my->vp_uint32;
                my->vp_uint32 = tmp;
        }
 
        if (fr_packet_pairs_from_packet(request->request_ctx, &request->request_pairs, request->packet) < 0) {
                RPEDEBUG("Failed decoding 'Net.*' packet");
                return -1;
        }
 
        return 0;
}
 
static ssize_t mod_encode(UNUSED void const *instance, request_t *request, uint8_t *buffer, size_t buffer_len)
{
//      proto_bfd_t const       *inst = talloc_get_type_abort_const(instance, proto_bfd_t);
        fr_io_track_t           *track = talloc_get_type_abort(request->async->packet_ctx, fr_io_track_t);
        fr_io_address_t const   *address = track->address;
        fr_client_t const       *client;
        bfd_wrapper_t const     *wrapper = (bfd_wrapper_t const *) request->packet->data;
        bfd_packet_t const      *bfd = (bfd_packet_t const *) wrapper->packet;
        fr_pair_t               *vp;
        ssize_t                 slen;
        fr_dbuff_t              dbuff;
 
        /*
         *      Process layer NAK, or "Do not respond".
         */
        if ((buffer_len == 1) || (wrapper->type == BFD_WRAPPER_RECV_PACKET) || (wrapper->type == BFD_WRAPPER_STATE_CHANGE)) {
                return 0;
        }
 
        client = address->radclient;
        fr_assert(client);
 
        fr_packet_pairs_to_packet(request->reply, &request->reply_pairs);
 
        /*
         *      Dynamic client stuff
         */
        if (client->dynamic && !client->active) {
                fr_client_t *new_client;
 
                fr_assert(buffer_len >= sizeof(client));
 
                /*
                 *      Allocate the client.  If that fails, send back a NAK.
                 *
                 *      @todo - deal with NUMA zones?  Or just deal with this
                 *      client being in different memory.
                 *
                 *      Maybe we should create a CONF_SECTION from the client,
                 *      and pass *that* back to mod_write(), which can then
                 *      parse it to create the actual client....
                 */
                new_client = client_afrom_request(NULL, request);
                if (!new_client) {
                        PERROR("Failed creating new client");
                        *buffer = true;
                        return 1;
                }
 
                memcpy(buffer, &new_client, sizeof(new_client));
                return sizeof(new_client);
        }
 
        fr_assert((wrapper->packet + bfd->length) == (request->packet->data + request->packet->data_len));
 
        /*
         *      Don't bother re-encoding the packet.
         */
        memcpy(buffer, bfd, bfd->length);
 
        fr_assert(fr_bfd_packet_ok(NULL, buffer, bfd->length));
 
        vp = fr_pair_find_by_da(&request->reply_pairs, NULL, attr_additional_data);
        if (!vp) return bfd->length;
 
        fr_dbuff_init(&dbuff, buffer + bfd->length, buffer_len - bfd->length);
        slen =  fr_internal_encode_list(&dbuff, &vp->vp_group, NULL);
        if (slen <= 0) return bfd->length;
 
        return bfd->length + slen;
}
 
/** Open listen sockets/connect to external event source
 *
 * @param[in] instance  Ctx data for this application.
 * @param[in] sc        to add our file descriptor to.
 * @param[in] conf      Listen section parsed to give us instance.
 * @return
 *      - 0 on success.
 *      - -1 on failure.
 */
static int mod_open(void *instance, fr_schedule_t *sc, UNUSED CONF_SECTION *conf)
{
        proto_bfd_t     *inst = talloc_get_type_abort(instance, proto_bfd_t);
 
        inst->io.app = &proto_bfd;
        inst->io.app_instance = instance;
 
        /*
         *      io.app_io should already be set
         */
        return fr_master_io_listen(inst, &inst->io, sc,
                                   inst->max_packet_size, inst->num_messages);
}
 
/** Instantiate the application
 *
 * Instantiate I/O and type submodules.
 *
 * @return
 *      - 0 on success.
 *      - -1 on failure.
 */
static int mod_instantiate(module_inst_ctx_t const *mctx)
{
        proto_bfd_t             *inst = talloc_get_type_abort(mctx->inst->data, proto_bfd_t);
 
        /*
         *      No IO module, it's an empty listener.
         */
        if (!inst->io.submodule) return 0;
 
        /*
         *      These configuration items are not printed by default,
         *      because normal people shouldn't be touching them.
         */
        if (!inst->max_packet_size && inst->io.app_io) inst->max_packet_size = inst->io.app_io->default_message_size;
 
        if (!inst->num_messages) inst->num_messages = 256;
 
        FR_INTEGER_BOUND_CHECK("num_messages", inst->num_messages, >=, 32);
        FR_INTEGER_BOUND_CHECK("num_messages", inst->num_messages, <=, 65535);
 
        FR_INTEGER_BOUND_CHECK("max_packet_size", inst->max_packet_size, >=, 1024);
        FR_INTEGER_BOUND_CHECK("max_packet_size", inst->max_packet_size, <=, 65535);
 
        /*
         *      Instantiate the master io submodule
         */
        return fr_master_app_io.common.instantiate(MODULE_INST_CTX(inst->io.dl_inst));
}
 
 
/** Bootstrap the application
 *
 * Bootstrap I/O and type submodules.
 *
 * @return
 *      - 0 on success.
 *      - -1 on failure.
 */
static int mod_bootstrap(module_inst_ctx_t const *mctx)
{
        proto_bfd_t             *inst = talloc_get_type_abort(mctx->inst->data, proto_bfd_t);
        CONF_SECTION            *server;
 
        /*
         *      Ensure that the server CONF_SECTION is always set.
         */
        inst->io.server_cs = cf_item_to_section(cf_parent(mctx->inst->conf));
 
        /*
         *      No IO module, it's an empty listener.
         */
        if (!inst->io.submodule) return 0;
 
        /*
         *      Tell the master handler about the main protocol instance.
         */
        inst->io.app = &proto_bfd;
        inst->io.app_instance = inst;
 
        /*
         *      We will need this for dynamic clients and connected sockets.
         */
        inst->io.dl_inst = dl_module_instance_by_data(inst);
        fr_assert(inst != NULL);
 
        server = inst->io.server_cs;
 
        inst->peers = cf_data_value(cf_data_find(server, fr_rb_tree_t, "peers"));
        if (!inst->peers) {
                CONF_SECTION *cs = NULL;
 
                inst->peers = fr_rb_inline_talloc_alloc(inst, fr_client_t, node, client_cmp, NULL);
                if (!inst->peers) return -1;
 
                while ((cs = cf_section_find_next(server, cs, "peer", CF_IDENT_ANY))) {
                        fr_client_t *c;
                        bfd_session_t *peer;
 
                        if (cf_section_rules_push(cs, peer_config) < 0) return -1;
 
                        c = client_afrom_cs(cs, cs, server, sizeof(bfd_session_t));
                        if (!c) {
                        error:
                                cf_log_err(cs, "Failed to parse peer %s", cf_section_name2(cs));
                                talloc_free(inst->peers);
                                return -1;
                        }
 
                        if (c->proto != IPPROTO_UDP) {
                                cf_log_err(cs, "Peer must use 'proto = udp' in %s", cf_section_name2(cs));
                                goto error;
                        }
 
                        peer = (bfd_session_t *) c;
 
                        FR_TIME_DELTA_BOUND_CHECK("peer.min_transmit_interval", peer->desired_min_tx_interval, >=, fr_time_delta_from_usec(32));
                        FR_TIME_DELTA_BOUND_CHECK("peer.min_transmit_interval", peer->desired_min_tx_interval, <=, fr_time_delta_from_sec(2));
 
                        FR_TIME_DELTA_BOUND_CHECK("peer.min_recieve_interval", peer->required_min_rx_interval, >=, fr_time_delta_from_usec(32));
                        FR_TIME_DELTA_BOUND_CHECK("peer.min_received_interval", peer->required_min_rx_interval, <=, fr_time_delta_from_sec(2));
 
                        FR_INTEGER_BOUND_CHECK("peer.max_timeouts", peer->detect_multi, >=, 1);
                        FR_INTEGER_BOUND_CHECK("peer.max_timeouts", peer->detect_multi, <=, 10);
 
                        if (((c->ipaddr.af == AF_INET) && (c->ipaddr.prefix != 32)) ||
                            ((c->ipaddr.af == AF_INET6) && (c->ipaddr.prefix != 128))) {
                                cf_log_err(cs, "Invalid IP prefix - cannot use ip/mask for BFD");
                                goto error;
                        }
 
                        /*
                         *      Secret and auth_type handling.
                         */
                        if (c->secret) {
                                if (!*c->secret) {
                                        cf_log_err(cs, "Secret cannot be an empty string");
                                        goto error;
                                }
 
                                peer->secret_len = talloc_array_length(c->secret) - 1;
                        }
 
                        switch (peer->auth_type) {
                        case BFD_AUTH_RESERVED:
                                if (c->secret) cf_log_warn(cs, "Ignoring 'secret' due to 'auth_type = none'");
                                break;
 
                        case BFD_AUTH_SIMPLE:
                        case BFD_AUTH_KEYED_MD5:
                        case BFD_AUTH_MET_KEYED_MD5:
                                if (!c->secret) {
                                        cf_log_err(cs, "A 'secret' must be specified when using 'auth_type = simple'");
                                        goto error;
                                }
 
                                if (strlen(c->secret) > 16) {
                                        cf_log_err(cs, "Length of 'secret' must be no more than 16 octets for 'auth_type = simple'");
                                        goto error;
                                }
                                break;
 
                        case BFD_AUTH_KEYED_SHA1:
                        case BFD_AUTH_MET_KEYED_SHA1:
                                if (!c->secret) {
                                        cf_log_err(cs, "A 'secret' must be specified when using 'auth_type = ...'");
                                        goto error;
                                }
 
                                if (strlen(c->secret) > 20) {
                                        cf_log_err(cs, "Length of 'secret' must be no more than 16 octets for 'auth_type = simple'");
                                        goto error;
                                }
                                break;
 
                        }
 
                        c->active = true;
 
                        if (!fr_rb_insert(inst->peers, c)) {
                                cf_log_err(cs, "Failed to add peer %s", cf_section_name2(cs));
                                goto error;
                        }
                }
 
                (void) cf_data_add(server, inst->peers, "peers", false);
        }
 
        /*
         *      Bootstrap the master IO handler.
         */
        return fr_master_app_io.common.bootstrap(MODULE_INST_CTX(inst->io.dl_inst));
}
 
static int mod_load(void)
{
        if (fr_bfd_global_init() < 0) {
                PERROR("Failed initialising protocol library");
                return -1;
        }
        return 0;
}
 
static void mod_unload(void)
{
        fr_bfd_global_free();
}
 
fr_app_t proto_bfd = {
        .common = {
                .magic                  = MODULE_MAGIC_INIT,
                .name                   = "bfd",
                .config                 = proto_bfd_config,
                .inst_size              = sizeof(proto_bfd_t),
                .onload                 = mod_load,
                .unload                 = mod_unload,
                .bootstrap              = mod_bootstrap,
                .instantiate            = mod_instantiate
        },
        .dict                   = &dict_bfd,
        .open                   = mod_open,
        .decode                 = mod_decode,
        .encode                 = mod_encode,
};