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/* ipv6_parser.c
*
* This file contains functions to parse IPv6 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"
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wpacked"
#pragma GCC diagnostic ignored "-Wattributes"
typedef struct __attribute__ ((__packed__)) ipv6_header_s {
#ifndef IPV6_VERSION_MASK
#define IPV6_VERSION_MASK 0xF0000000
#endif
#ifndef IPV6_TC_MASK
#define IPV6_TC_MASK 0x0FF00000
#endif
#ifndef IPV6_FLOW_MASK
#define IPV6_FLOW_MASK 0x000FFFFF
#endif
uint32_t vtf;
uint16_t dataLength;
uint8_t nextHeader;
#define IPV6_NHDR_HBH 0
#define IPV6_NHDR_TCP 6
#define IPV6_NHDR_UDP 17
#define IPV6_NHDR_ENCIP6 41
#define IPV6_NHDR_ROUT 43
#define IPV6_NHDR_FRAG 44
#define IPV6_NHDR_RRSV 46
#define IPV6_NHDR_SEC 50
#define IPV6_NHDR_AUTH 51
#define IPV6_NHDR_ICMP6 58
#define IPV6_NHDR_NONHDR 59
#define IPV6_NHDR_DOPTS 60
uint8_t hopLimit;
uint8_t addrSrc[16];
uint8_t addrDst[16];
} ipv6_header_t;
#pragma GCC diagnostic pop
#ifndef IPV6_VERSION
#define IPV6_VERSION(h) (ntohl(h->vtf) & IPV6_VERSION_MASK)>>28
#endif
#ifndef IPV6_TC
#define IPV6_TC(h) (ntohl(h->vtf) & IPV6_TC_MASK)>>20
#endif
#ifndef IPV6_FLOW
#define IPV6_FLOW(h) (ntohl(h->vtf) & IPV6_FLOW_MASK)
#endif
/* extension headers */
typedef struct hbh_header_s {
uint8_t nextHeader;
uint8_t hLength;
uint8_t *pOptions;
} hbh_header_t;
typedef struct dest_header_s {
uint8_t nextHeader;
uint8_t hLength;
uint8_t *pOptions;
} dest_header_t;
typedef struct route_header_s {
uint8_t nextHeader;
uint8_t hLength;
uint8_t rType;
uint8_t segsLeft;
uint32_t reserved;
uint8_t addrs[16];
} route_header_t;
typedef struct frag_header_s {
uint8_t nextHeader;
uint8_t reserved;
uint16_t offsetFlags;
uint32_t id;
} frag_header_t;
static inline uint8_t hbh_header_parse(const uchar **packet, int *pktSize) {
DBGPRINTF("hbh_header_parse\n");
/* Union to prevent cast from uchar to hbh_header_t */
union {
const uchar *pck;
hbh_header_t *hdr;
} hbh_header_to_char;
hbh_header_to_char.pck = *packet;
hbh_header_t *hbh_header = hbh_header_to_char.hdr;
/* hbh_header->hLength is the number of octets of header in 8-octet units minus 1
* the header length SHOULD be a multiple of 8 */
uint8_t hByteLength = hbh_header->hLength * 8 + 8;
DBGPRINTF("hByteLength: %d\n", hByteLength);
*pktSize -= hByteLength;
*packet += hByteLength;
return hbh_header->nextHeader;
}
static inline uint8_t dest_header_parse(const uchar **packet, int *pktSize) {
DBGPRINTF("dest_header_parse\n");
/* Union to prevent cast from uchar to dest_header_t */
union {
const uchar *pck;
dest_header_t *hdr;
} dest_header_to_char;
dest_header_to_char.pck = *packet;
dest_header_t *dest_header = dest_header_to_char.hdr;
/* dest_header->hLength is the number of octets of header in 8-octet units minus 1
* the header length SHOULD be a multiple of 8 */
uint8_t hByteLength = dest_header->hLength * 8 + 8;
DBGPRINTF("hByteLength: %d\n", hByteLength);
*pktSize -= hByteLength;
*packet += hByteLength;
return dest_header->nextHeader;
}
static inline uint8_t route_header_parse(const uchar **packet, int *pktSize, struct json_object *jparent) {
DBGPRINTF("route_header_parse\n");
/* Union to prevent cast from uchar to route_header_t */
union {
const uchar *pck;
route_header_t *hdr;
} route_header_to_char;
route_header_to_char.pck = *packet;
route_header_t *route_header = route_header_to_char.hdr;
/* route_header->hLength is the number of octets of header in 8-octet units minus 1
* the header length (in bytes) SHOULD be a multiple of 8 */
uint8_t hByteLength = route_header->hLength * 8 + 8;
*pktSize -= hByteLength;
*packet += hByteLength;
if (route_header->rType == 0) {
json_object_object_add(jparent, "IP6_route_seg_left", json_object_new_int(route_header->segsLeft));
hByteLength -= 8; //leave only length of routing addresses
char addrStr[40], routeFieldName[20];
int addrNum = 1;
uint8_t *addr = &(route_header->addrs[0]);
//while there is enough space for an IPv6 address
while (hByteLength >= 16) {
inet_ntop(AF_INET6, (void *)addr, addrStr, 40);
snprintf(routeFieldName, 20, "IP6_route_%d", addrNum++);
json_object_object_add(jparent, routeFieldName, json_object_new_string((char *)addrStr));
addr += 16;
hByteLength -= 16;
}
}
return route_header->nextHeader;
}
#define FRAG_OFFSET_MASK 0xFFF8
#define MFLAG_MASK 0x0001
static inline uint8_t frag_header_parse(const uchar **packet, int *pktSize, struct json_object *jparent) {
DBGPRINTF("frag_header_parse\n");
/* Union to prevent cast from uchar to frag_header_t */
union {
const uchar *pck;
frag_header_t *hdr;
} frag_header_to_char;
frag_header_to_char.pck = *packet;
frag_header_t *frag_header = frag_header_to_char.hdr;
uint16_t flags = ntohs(frag_header->offsetFlags);
json_object_object_add(jparent, "IP6_frag_offset", json_object_new_int((flags & FRAG_OFFSET_MASK) >> 3));
json_object_object_add(jparent, "IP6_frag_more", json_object_new_boolean(flags & MFLAG_MASK));
json_object_object_add(jparent, "IP6_frag_id", json_object_new_int64(frag_header->id));
*pktSize -= 8;
*packet += 8;
return frag_header->nextHeader;
}
/*
* This function parses the bytes in the received packet to extract IPv6 metadata.
*
* its parameters are:
* - a pointer on the list of bytes representing the packet
* the first byte must be the beginning of the IPv6 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 IPv6 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 *ipv6_parse(const uchar *packet, int pktSize, struct json_object *jparent) {
DBGPRINTF("ipv6_parse\n");
DBGPRINTF("packet size %d\n", pktSize);
if (pktSize < 40) { /* too small for IPv6 header + data (header might be longer)*/
DBGPRINTF("IPv6 packet too small : %d\n", pktSize);
RETURN_DATA_AFTER(0)
}
ipv6_header_t *ipv6_header = (ipv6_header_t *)packet;
char addrSrc[40], addrDst[40];
inet_ntop(AF_INET6, (void *)&ipv6_header->addrSrc, addrSrc, 40);
inet_ntop(AF_INET6, (void *)&ipv6_header->addrDst, addrDst, 40);
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, "net_ttl", json_object_new_int(ipv6_header->hopLimit));
uint8_t nextHeader = ipv6_header->nextHeader;
packet += sizeof(ipv6_header_t);
pktSize -= sizeof(ipv6_header_t);
DBGPRINTF("beginning ext headers scan\n");
uint8_t hasNext = 1;
do {
switch (nextHeader) {
case IPV6_NHDR_HBH:
nextHeader = hbh_header_parse(&packet, &pktSize);
break;
case IPV6_NHDR_TCP:
json_object_object_add(jparent, "IP_proto", json_object_new_int(nextHeader));
return tcp_parse(packet, pktSize, jparent);
case IPV6_NHDR_UDP:
json_object_object_add(jparent, "IP_proto", json_object_new_int(nextHeader));
return udp_parse(packet, pktSize, jparent);
case IPV6_NHDR_ENCIP6:
hasNext = 0;
break;
case IPV6_NHDR_ROUT:
nextHeader = route_header_parse(&packet, &pktSize, jparent);
break;
case IPV6_NHDR_FRAG:
nextHeader = frag_header_parse(&packet, &pktSize, jparent);
break;
case IPV6_NHDR_RRSV:
hasNext = 0;
break;
case IPV6_NHDR_SEC:
hasNext = 0;
break;
case IPV6_NHDR_AUTH:
hasNext = 0;
break;
case IPV6_NHDR_ICMP6:
json_object_object_add(jparent, "IP_proto", json_object_new_int(nextHeader));
return icmp_parse(packet, pktSize, jparent);
case IPV6_NHDR_NONHDR:
hasNext = 0;
break;
case IPV6_NHDR_DOPTS:
nextHeader = dest_header_parse(&packet, &pktSize);
break;
default:
hasNext = 0;
break;
}
} while (hasNext);
json_object_object_add(jparent, "IP_proto", json_object_new_int(nextHeader));
RETURN_DATA_AFTER(0)
}
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