decode.c

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/*
 *   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
 */
 
/**
 * $Id: 869c0953c554275994f1280f97aea874a7e08eae $
 *
 * @file protocols/bfd/decode.c
 * @brief Functions to decode BFD packets
 *
 * @copyright 2023 Network RADIUS SAS (legal@networkradius.com)
 */
RCSID("$Id: 869c0953c554275994f1280f97aea874a7e08eae $")
 
#include <freeradius-devel/util/struct.h>
#include <freeradius-devel/io/test_point.h>
#include <freeradius-devel/internal/internal.h>
 
#include "attrs.h"
 
static ssize_t decode_value(TALLOC_CTX *ctx, fr_pair_list_t *out,
                            fr_dict_attr_t const *parent,
                            uint8_t const *data, size_t const data_len, UNUSED void *decode_ctx)
{
        ssize_t slen;
        fr_pair_t *vp;
 
        FR_PROTO_HEX_DUMP(data, data_len, "decode_value");
 
        vp = fr_pair_afrom_da(ctx, parent);
        if (!vp) return PAIR_DECODE_OOM;
 
        slen =  fr_value_box_from_network(vp, &vp->data, vp->vp_type, vp->da,
                                          &FR_DBUFF_TMP(data, data_len), data_len, true);
        if (slen < 0) {
                talloc_free(vp);
                return slen;
        }
 
        fr_assert(vp != NULL);
 
        vp->vp_tainted = true;
        fr_pair_append(out, vp);
 
        return data_len;
}
 
 
/** Decode a raw BFD packet into VPs.
 *
 */
ssize_t fr_bfd_decode(TALLOC_CTX *ctx, fr_pair_list_t *out,
                      uint8_t const *packet, size_t packet_len,
                      char const *secret, UNUSED size_t secret_len)
{
        ssize_t                 slen;
        fr_bfd_ctx_t            packet_ctx;
        bfd_packet_t const      *bfd;
        fr_pair_t               *vp;
        fr_dbuff_t              dbuff;
 
        packet_ctx.secret = secret;
 
        bfd = (bfd_packet_t const *) packet;
 
        slen = fr_struct_from_network(ctx, out, attr_bfd_packet, packet, bfd->length,
                                      &packet_ctx, decode_value, NULL);
        if (slen < 0) return slen;
 
        if (bfd->length == packet_len) return packet_len;
 
        /*
         *      Try to decode additional data.
         */
        vp = fr_pair_afrom_da(ctx, attr_bfd_additional_data);
        if (!vp) return packet_len;
 
        fr_dbuff_init(&dbuff, packet + slen, packet_len - slen);
 
        if ((fr_internal_decode_list_dbuff(vp, &vp->vp_group, fr_dict_root(dict_bfd), &dbuff, NULL) < 0) ||
            (fr_pair_list_num_elements(&vp->vp_group) == 0)) {
                TALLOC_FREE(vp);
        } else {
                fr_pair_append(out, vp);
        }
 
        return slen;
}
 
static int decode_test_ctx(void **out, TALLOC_CTX *ctx, UNUSED fr_dict_t const *dict,
                           UNUSED fr_dict_attr_t const *root_da)
{
        fr_bfd_ctx_t    *test_ctx;
 
        test_ctx = talloc_zero(ctx, fr_bfd_ctx_t);
        test_ctx->secret = talloc_strdup(test_ctx, "testing123");
        test_ctx->tmp_ctx = talloc_zero(test_ctx, uint8_t);
 
        *out = test_ctx;
 
        return 0;
}
 
static ssize_t fr_bfd_decode_proto(TALLOC_CTX *ctx, fr_pair_list_t *out,
                                   uint8_t const *data, size_t data_len, void *proto_ctx)
{
        fr_pair_t       *vp;
        bfd_packet_t const *packet;
        fr_bfd_ctx_t    *test_ctx = talloc_get_type_abort(proto_ctx, fr_bfd_ctx_t);
 
        if (data_len < FR_BFD_HEADER_LENGTH) {
                fr_strerror_const("Packet is too small for BFD");
                return -1;
        }
 
        packet = (bfd_packet_t const *) data;
 
        if (packet->length > data_len) {
                fr_strerror_const("Packet.length is larger than received data");
                return -1;
        }
 
        if (packet->length < FR_BFD_HEADER_LENGTH) {
                fr_strerror_const("Packet.length is smaller then BFD header size");
                return -1;
        }
 
        if (packet->version != 1) {
                fr_strerror_const("Packet.version has invalid value");
                return -1;
        }
 
        if (packet->detect_multi == 0) {
                fr_strerror_const("Packet.detect-multi has invalid value zero");
                return -1;
        }
 
        if (packet->detect_multi == 0) {
                fr_strerror_const("Packet.detect-multi has invalid value zero");
                return -1;
        }
 
        if (packet->multipoint != 0) {
                fr_strerror_const("Packet.multipoint has invalid non-zero value");
                return -1;
        }
 
        if (packet->my_disc == 0) {
                fr_strerror_const("Packet.my-discriminator has invalid value zero");
                return -1;
        }
 
        if ((packet->your_disc == 0) &&
            !((packet->state == BFD_STATE_DOWN) ||
              (packet->state == BFD_STATE_ADMIN_DOWN))) {
                fr_strerror_const("Packet has invalid values for your-discriminator and state");
                return 0;
        }
 
        /*
         *      Get the packet type.
         */
        vp = fr_pair_afrom_da(ctx, attr_packet_type);
        if (!vp) {
                fr_strerror_const("Failed creating Packet-Type");
                return -1;
        }
 
        vp->vp_uint32 = packet->state;
        fr_pair_append(out, vp);
 
#if 0
        /*
         *      We always decode the packet as a nested VP.
         */
        vp = fr_pair_afrom_da(ctx, attr_bfd_packet);
        if (!vp) {
                fr_strerror_const("Failed creating Packet");
                return -1;
        }
        fr_pair_append(out, vp);
#endif
 
        /* coverity[tainted_data] */
        return fr_bfd_decode(ctx, out, data, data_len,
                             test_ctx->secret, talloc_array_length(test_ctx->secret) - 1);
}
 
/*
 *      Test points
 */
extern fr_test_point_proto_decode_t bfd_tp_decode_proto;
fr_test_point_proto_decode_t bfd_tp_decode_proto = {
        .test_ctx       = decode_test_ctx,
        .func           = fr_bfd_decode_proto
};