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Diffstat (limited to 'contrib/impcap/icmp_parser.c')
| -rw-r--r-- | contrib/impcap/icmp_parser.c | 79 |
1 files changed, 79 insertions, 0 deletions
diff --git a/contrib/impcap/icmp_parser.c b/contrib/impcap/icmp_parser.c new file mode 100644 index 0000000..8a627ee --- /dev/null +++ b/contrib/impcap/icmp_parser.c @@ -0,0 +1,79 @@ +/* icmp_parser.c + * + * This file contains functions to parse ICMP headers. + * + * File begun on 2018-11-13 + * + * Created by: + * - Théo Bertin (theo.bertin@advens.fr) + * + * With: + * - François Bernard (francois.bernard@isen.yncrea.fr) + * - Tianyu Geng (tianyu.geng@isen.yncrea.fr) + * + * This file is part of rsyslog. + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * -or- + * see COPYING.ASL20 in the source distribution + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +#include "config.h" +#include "parsers.h" + +struct icmp_header_s { + uint8_t type; + uint8_t code; + uint16_t checksum; + uint8_t data[]; +}; + +typedef struct icmp_header_s icmp_header_t; + +/* + * This function parses the bytes in the received packet to extract ICMP metadata. + * + * its parameters are: + * - a pointer on the list of bytes representing the packet + * the first byte must be the beginning of the ICMP header + * - the size of the list passed as first parameter + * - a pointer on a json_object, containing all the metadata recovered so far + * this is also where ICMP metadata will be added + * + * This function returns a structure containing the data unprocessed by this parser + * or the ones after (as a list of bytes), and the length of this data. +*/ +data_ret_t *icmp_parse(const uchar *packet, int pktSize, struct json_object *jparent) { + DBGPRINTF("icmp_parse\n"); + DBGPRINTF("packet size %d\n", pktSize); + + if (pktSize < 8) { + DBGPRINTF("ICMP packet too small : %d\n", pktSize); + RETURN_DATA_AFTER(0); + } + + /* Union to prevent cast from uchar to icmp_header_t */ + union { + const uchar *pck; + icmp_header_t *hdr; + } icmp_header_to_char; + + icmp_header_to_char.pck = packet; + icmp_header_t *icmp_header = icmp_header_to_char.hdr; + + json_object_object_add(jparent, "net_icmp_type", json_object_new_int(icmp_header->type)); + json_object_object_add(jparent, "net_icmp_code", json_object_new_int(icmp_header->code)); + json_object_object_add(jparent, "icmp_checksum", json_object_new_int(ntohs(icmp_header->checksum))); + + RETURN_DATA_AFTER(8) +} |