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200 lines
8.0 KiB
C
200 lines
8.0 KiB
C
/* Copyright (C) 2007-2024 Open Information Security Foundation
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*
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* You can copy, redistribute or modify this Program under the terms of
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* the GNU General Public License version 2 as published by the Free
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* Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* version 2 along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301, USA.
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*/
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/**
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* \file
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*
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* \author Victor Julien <victor@inliniac.net>
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* \author Brian Rectanus <brectanu@gmail.com>
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*/
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#ifndef SURICATA_DECODE_IPV4_H
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#define SURICATA_DECODE_IPV4_H
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#define IPV4_HEADER_LEN 20 /**< Header length */
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#define IPV4_OPTMAX 40 /**< Max options length */
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#define IPV4_MAXPACKET_LEN 65535 /**< Maximum packet size */
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/** IP Option Types */
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#define IPV4_OPT_EOL 0x00 /**< Option: End of List */
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#define IPV4_OPT_NOP 0x01 /**< Option: No op */
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#define IPV4_OPT_RR 0x07 /**< Option: Record Route */
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#define IPV4_OPT_QS 0x19 /**< Option: Quick Start */
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#define IPV4_OPT_TS 0x44 /**< Option: Timestamp */
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#define IPV4_OPT_SEC 0x82 /**< Option: Security */
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#define IPV4_OPT_LSRR 0x83 /**< Option: Loose Source Route */
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#define IPV4_OPT_ESEC 0x85 /**< Option: Extended Security */
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#define IPV4_OPT_CIPSO 0x86 /**< Option: Commercial IP Security */
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#define IPV4_OPT_SID 0x88 /**< Option: Stream Identifier */
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#define IPV4_OPT_SSRR 0x89 /**< Option: Strict Source Route */
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#define IPV4_OPT_RTRALT 0x94 /**< Option: Router Alert */
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/** IP Option Lengths (fixed) */
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#define IPV4_OPT_SID_LEN 4 /**< SID Option Fixed Length */
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#define IPV4_OPT_RTRALT_LEN 4 /**< RTRALT Option Fixed Length */
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/** IP Option Lengths (variable) */
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#define IPV4_OPT_SEC_MIN 3 /**< SEC, ESEC Option Min Length */
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#define IPV4_OPT_ROUTE_MIN 3 /**< RR, SRR, LTRR Option Min Length */
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#define IPV4_OPT_QS_MIN 8 /**< QS Option Min Length */
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#define IPV4_OPT_TS_MIN 5 /**< TS Option Min Length */
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#define IPV4_OPT_CIPSO_MIN 10 /**< CIPSO Option Min Length */
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/** IP Option fields */
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#define IPV4_OPTS ip4vars.ip_opts
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#define IPV4_OPTS_CNT ip4vars.ip_opt_cnt
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typedef struct IPV4Opt_ {
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/** \todo We may want to break type up into its 3 fields
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* as the reassembler may want to know which options
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* must be copied to each fragment.
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*/
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uint8_t type; /**< option type */
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uint8_t len; /**< option length (type+len+data) */
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const uint8_t *data; /**< option data */
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} IPV4Opt;
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typedef struct IPV4Hdr_
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{
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uint8_t ip_verhl; /**< version & header length */
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uint8_t ip_tos; /**< type of service */
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uint16_t ip_len; /**< length */
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uint16_t ip_id; /**< id */
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uint16_t ip_off; /**< frag offset */
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uint8_t ip_ttl; /**< time to live */
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uint8_t ip_proto; /**< protocol (tcp, udp, etc) */
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uint16_t ip_csum; /**< checksum */
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union {
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struct {
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struct in_addr ip_src;/**< source address */
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struct in_addr ip_dst;/**< destination address */
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} ip4_un1;
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uint16_t ip_addrs[4];
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} ip4_hdrun1;
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} IPV4Hdr;
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#define s_ip_src ip4_hdrun1.ip4_un1.ip_src
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#define s_ip_dst ip4_hdrun1.ip4_un1.ip_dst
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#define s_ip_addrs ip4_hdrun1.ip_addrs
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#define IPV4_GET_RAW_VER(ip4h) (((ip4h)->ip_verhl & 0xf0) >> 4)
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#define IPV4_GET_RAW_HLEN(ip4h) (uint8_t)(((ip4h)->ip_verhl & (uint8_t)0x0f) << (uint8_t)2)
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#define IPV4_GET_RAW_IPTOS(ip4h) ((ip4h)->ip_tos)
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#define IPV4_GET_RAW_IPLEN(ip4h) (SCNtohs((ip4h)->ip_len))
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#define IPV4_GET_RAW_IPID(ip4h) (SCNtohs((ip4h)->ip_id))
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#define IPV4_GET_RAW_IPOFFSET(ip4h) SCNtohs((ip4h)->ip_off)
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#define IPV4_GET_RAW_FRAGOFFSET(ip4h) (IPV4_GET_RAW_IPOFFSET((ip4h)) & 0x1fff)
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#define IPV4_GET_RAW_IPTTL(ip4h) ((ip4h)->ip_ttl)
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#define IPV4_GET_RAW_IPPROTO(ip4h) ((ip4h)->ip_proto)
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#define IPV4_GET_RAW_IPSRC(ip4h) ((ip4h)->s_ip_src)
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#define IPV4_GET_RAW_IPDST(ip4h) ((ip4h)->s_ip_dst)
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/** return the raw (directly from the header) src ip as uint32_t */
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#define IPV4_GET_RAW_IPSRC_U32(ip4h) (uint32_t)((ip4h)->s_ip_src.s_addr)
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/** return the raw (directly from the header) dst ip as uint32_t */
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#define IPV4_GET_RAW_IPDST_U32(ip4h) (uint32_t)((ip4h)->s_ip_dst.s_addr)
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#define IPV4_GET_RAW_FLAG_MF(ip4h) ((IPV4_GET_RAW_IPOFFSET((ip4h)) & 0x2000) != 0)
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#define IPV4_GET_RAW_FLAG_DF(ip4h) ((IPV4_GET_RAW_IPOFFSET((ip4h)) & 0x4000) != 0)
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#define IPV4_GET_RAW_FLAG_RF(ip4h) ((IPV4_GET_RAW_IPOFFSET((ip4h)) & 0x8000) != 0)
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#define IPV4_OPT_FLAG_EOL BIT_U16(1)
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#define IPV4_OPT_FLAG_NOP BIT_U16(2)
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#define IPV4_OPT_FLAG_RR BIT_U16(3)
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#define IPV4_OPT_FLAG_TS BIT_U16(4)
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#define IPV4_OPT_FLAG_QS BIT_U16(5)
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#define IPV4_OPT_FLAG_LSRR BIT_U16(6)
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#define IPV4_OPT_FLAG_SSRR BIT_U16(7)
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#define IPV4_OPT_FLAG_SID BIT_U16(8)
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#define IPV4_OPT_FLAG_SEC BIT_U16(9)
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#define IPV4_OPT_FLAG_CIPSO BIT_U16(10)
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#define IPV4_OPT_FLAG_RTRALT BIT_U16(11)
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#define IPV4_OPT_FLAG_ESEC BIT_U16(12)
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/* helper structure with parsed ipv4 info */
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typedef struct IPV4Vars_ {
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uint16_t opt_cnt;
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uint16_t opts_set;
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} IPV4Vars;
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void DecodeIPV4RegisterTests(void);
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/** ----- Inline functions ----- */
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/**
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* \brief Calculate or validate the checksum for the IP packet
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*
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* \param pkt Pointer to the start of the IP packet
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* \param hlen Length of the IP header
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* \param init The current checksum if validating, 0 if generating.
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*
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* \retval csum For validation 0 will be returned for success, for calculation
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* this will be the checksum.
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*/
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static inline uint16_t IPV4Checksum(const uint16_t *pkt, uint16_t hlen, uint16_t init)
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{
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uint32_t csum = init;
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csum += pkt[0] + pkt[1] + pkt[2] + pkt[3] + pkt[4] + pkt[6] + pkt[7] +
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pkt[8] + pkt[9];
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hlen -= 20;
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pkt += 10;
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if (hlen == 0) {
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;
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} else if (hlen == 4) {
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csum += pkt[0] + pkt[1];
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} else if (hlen == 8) {
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csum += pkt[0] + pkt[1] + pkt[2] + pkt[3];
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} else if (hlen == 12) {
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csum += pkt[0] + pkt[1] + pkt[2] + pkt[3] + pkt[4] + pkt[5];
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} else if (hlen == 16) {
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csum += pkt[0] + pkt[1] + pkt[2] + pkt[3] + pkt[4] + pkt[5] + pkt[6] +
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pkt[7];
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} else if (hlen == 20) {
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csum += pkt[0] + pkt[1] + pkt[2] + pkt[3] + pkt[4] + pkt[5] + pkt[6] +
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pkt[7] + pkt[8] + pkt[9];
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} else if (hlen == 24) {
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csum += pkt[0] + pkt[1] + pkt[2] + pkt[3] + pkt[4] + pkt[5] + pkt[6] +
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pkt[7] + pkt[8] + pkt[9] + pkt[10] + pkt[11];
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} else if (hlen == 28) {
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csum += pkt[0] + pkt[1] + pkt[2] + pkt[3] + pkt[4] + pkt[5] + pkt[6] +
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pkt[7] + pkt[8] + pkt[9] + pkt[10] + pkt[11] + pkt[12] + pkt[13];
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} else if (hlen == 32) {
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csum += pkt[0] + pkt[1] + pkt[2] + pkt[3] + pkt[4] + pkt[5] + pkt[6] +
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pkt[7] + pkt[8] + pkt[9] + pkt[10] + pkt[11] + pkt[12] + pkt[13] +
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pkt[14] + pkt[15];
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} else if (hlen == 36) {
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csum += pkt[0] + pkt[1] + pkt[2] + pkt[3] + pkt[4] + pkt[5] + pkt[6] +
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pkt[7] + pkt[8] + pkt[9] + pkt[10] + pkt[11] + pkt[12] + pkt[13] +
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pkt[14] + pkt[15] + pkt[16] + pkt[17];
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} else if (hlen == 40) {
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csum += pkt[0] + pkt[1] + pkt[2] + pkt[3] + pkt[4] + pkt[5] + pkt[6] +
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pkt[7] + pkt[8] + pkt[9] + pkt[10] + pkt[11] + pkt[12] + pkt[13] +
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pkt[14] + pkt[15] + pkt[16] + pkt[17] + pkt[18] + pkt[19];
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}
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csum = (csum >> 16) + (csum & 0x0000FFFF);
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csum += (csum >> 16);
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return (uint16_t) ~csum;
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}
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#endif /* SURICATA_DECODE_IPV4_H */
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