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Diffstat (limited to 'contrib/impcap/ipv4_parser.c')
| -rw-r--r-- | contrib/impcap/ipv4_parser.c | 101 |
1 files changed, 101 insertions, 0 deletions
diff --git a/contrib/impcap/ipv4_parser.c b/contrib/impcap/ipv4_parser.c new file mode 100644 index 0000000..2693c60 --- /dev/null +++ b/contrib/impcap/ipv4_parser.c @@ -0,0 +1,101 @@ +/* ipv4_parser.c + * + * This file contains functions to parse IP 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 ipv4_header_s { +/*#if __BYTE_ORDER == __BIG_ENDIAN + unsigned char version:4; + unsigned char ihl:4; +#else*/ + unsigned char ihl:4; + unsigned char version:4; +//#endif + uint8_t service; + uint16_t totLen; + uint16_t id; + uint16_t frag; + uint8_t ttl; + uint8_t proto; + uint16_t hdrChksum; + uint8_t addrSrc[4]; + uint8_t addrDst[4]; + uint8_t pOptions[]; +}; + +typedef struct ipv4_header_s ipv4_header_t; + +/* + * This function parses the bytes in the received packet to extract IP metadata. + * + * its parameters are: + * - a pointer on the list of bytes representing the packet + * the first byte must be the beginning of the IP 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 IP 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 *ipv4_parse(const uchar *packet, int pktSize, struct json_object *jparent) { + DBGPRINTF("ipv4_parse\n"); + DBGPRINTF("packet size %d\n", pktSize); + + if (pktSize < 20) { /* too small for IPv4 header + data (header might be longer)*/ + DBGPRINTF("IPv4 packet too small : %d\n", pktSize); + RETURN_DATA_AFTER(0) + } + + /* Union to prevent cast from uchar to ipv4_header_t */ + union { + const uchar *pck; + ipv4_header_t *hdr; + } ipv4_header_to_char; + + ipv4_header_to_char.pck = packet; + ipv4_header_t *ipv4_header = ipv4_header_to_char.hdr; + + char addrSrc[20], addrDst[20]; + uint8_t hdrLen = 4 * ipv4_header->ihl; /* 4 x length in words */ + + inet_ntop(AF_INET, (void *)&ipv4_header->addrSrc, addrSrc, 20); + inet_ntop(AF_INET, (void *)&ipv4_header->addrDst, addrDst, 20); + + json_object_object_add(jparent, "net_dst_ip", json_object_new_string((char *)addrDst)); + json_object_object_add(jparent, "net_src_ip", json_object_new_string((char *)addrSrc)); + json_object_object_add(jparent, "IP_ihl", json_object_new_int(ipv4_header->ihl)); + json_object_object_add(jparent, "net_ttl", json_object_new_int(ipv4_header->ttl)); + json_object_object_add(jparent, "IP_proto", json_object_new_int(ipv4_header->proto)); + + + return ip_proto_parse(ipv4_header->proto, (packet + hdrLen), (pktSize - hdrLen), jparent); +} |