/src/decode-tcp.h
https://github.com/decanio/suricata-tilera · C Header · 300 lines · 191 code · 53 blank · 56 comment · 12 complexity · 585515414fa0de2e6129dffd02c555a3 MD5 · raw file
- /* Copyright (C) 2007-2010 Open Information Security Foundation
- *
- * You can copy, redistribute or modify this Program under the terms of
- * the GNU General Public License version 2 as published by the Free
- * Software Foundation.
- *
- * This program 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 General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * version 2 along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
- * 02110-1301, USA.
- */
- /**
- * \file
- *
- * \author Victor Julien <victor@inliniac.net>
- * \todo RAW* macro's should be returning the raw value, not the host order
- */
- #ifndef __DECODE_TCP_H__
- #define __DECODE_TCP_H__
- #define TCP_HEADER_LEN 20
- #define TCP_OPTLENMAX 40
- #define TCP_OPTMAX 20 /* every opt is at least 2 bytes
- * (type + len), except EOL and NOP */
- /* TCP flags */
- #define TH_FIN 0x01
- #define TH_SYN 0x02
- #define TH_RST 0x04
- #define TH_PUSH 0x08
- #define TH_ACK 0x10
- #define TH_URG 0x20
- /** Establish a new connection reducing window */
- #define TH_ECN 0x40
- /** Echo Congestion flag */
- #define TH_CWR 0x80
- /* tcp option codes */
- #define TCP_OPT_EOL 0x00
- #define TCP_OPT_NOP 0x01
- #define TCP_OPT_MSS 0x02
- #define TCP_OPT_WS 0x03
- #define TCP_OPT_SACKOK 0x04
- #define TCP_OPT_SACK 0x05
- #define TCP_OPT_TS 0x08
- #define TCP_OPT_SACKOK_LEN 2
- #define TCP_OPT_WS_LEN 3
- #define TCP_OPT_TS_LEN 10
- #define TCP_OPT_MSS_LEN 4
- #define TCP_OPT_SACK_MIN_LEN 10 /* hdr 2, 1 pair 8 = 10 */
- #define TCP_OPT_SACK_MAX_LEN 34 /* hdr 2, 4 pair 32= 34 */
- /** Max valid wscale value. */
- #define TCP_WSCALE_MAX 14
- #define TCP_OPTS tcpvars.tcp_opts
- #define TCP_OPTS_CNT tcpvars.tcp_opt_cnt
- #define TCP_GET_RAW_OFFSET(tcph) (((tcph)->th_offx2 & 0xf0) >> 4)
- #define TCP_GET_RAW_X2(tcph) ((tcph)->th_offx2 & 0x0f)
- #define TCP_GET_RAW_SRC_PORT(tcph) ntohs((tcph)->th_sport)
- #define TCP_GET_RAW_DST_PORT(tcph) ntohs((tcph)->th_dport)
- #define TCP_SET_RAW_TCP_OFFSET(tcph, value) ((tcph)->th_offx2 = (unsigned char)(((tcph)->th_offx2 & 0x0f) | (value << 4)))
- #define TCP_SET_RAW_TCP_X2(tcph, value) ((tcph)->th_offx2 = (unsigned char)(((tcph)->th_offx2 & 0xf0) | (value & 0x0f)))
- #define TCP_GET_RAW_SEQ(tcph) ntohl((tcph)->th_seq)
- #define TCP_GET_RAW_ACK(tcph) ntohl((tcph)->th_ack)
- #define TCP_GET_RAW_WINDOW(tcph) ntohs((tcph)->th_win)
- #define TCP_GET_RAW_URG_POINTER(tcph) ntohs((tcph)->th_urp)
- /** macro for getting the first timestamp from the packet. Timestamp is in host
- * order and either returned from the cache or from the packet directly. */
- #define TCP_GET_TSVAL(p) \
- (uint32_t)ntohl((*(uint32_t *)(p)->tcpvars.ts->data))
- /** macro for getting the second timestamp from the packet. Timestamp is in
- * host order and either returned from the cache or from the packet directly. */
- #define TCP_GET_TSECR(p) \
- (uint32_t)ntohl((*(uint32_t *)((p)->tcpvars.ts->data+4)))
- /** macro for getting the wscale from the packet. */
- #define TCP_GET_WSCALE(p) ((p)->tcpvars.ws ? (((*(uint8_t *)(p)->tcpvars.ws->data) <= TCP_WSCALE_MAX) ? (*(uint8_t *)((p)->tcpvars.ws->data)) : 0) : 0)
- #define TCP_GET_SACKOK(p) ((p)->tcpvars.sackok ? 1 : 0)
- #define TCP_GET_SACK_PTR(p) (p)->tcpvars.sack ? (p)->tcpvars.sack->data : NULL
- #define TCP_GET_SACK_CNT(p) ((p)->tcpvars.sack ? (((p)->tcpvars.sack->len - 2) / 8) : 0)
- #define TCP_GET_OFFSET(p) TCP_GET_RAW_OFFSET((p)->tcph)
- #define TCP_GET_HLEN(p) (TCP_GET_OFFSET((p)) << 2)
- #define TCP_GET_SRC_PORT(p) TCP_GET_RAW_SRC_PORT((p)->tcph)
- #define TCP_GET_DST_PORT(p) TCP_GET_RAW_DST_PORT((p)->tcph)
- #define TCP_GET_SEQ(p) TCP_GET_RAW_SEQ((p)->tcph)
- #define TCP_GET_ACK(p) TCP_GET_RAW_ACK((p)->tcph)
- #define TCP_GET_WINDOW(p) TCP_GET_RAW_WINDOW((p)->tcph)
- #define TCP_GET_URG_POINTER(p) TCP_GET_RAW_URG_POINTER((p)->tcph)
- #define TCP_ISSET_FLAG_FIN(p) ((p)->tcph->th_flags & TH_FIN)
- #define TCP_ISSET_FLAG_SYN(p) ((p)->tcph->th_flags & TH_SYN)
- #define TCP_ISSET_FLAG_RST(p) ((p)->tcph->th_flags & TH_RST)
- #define TCP_ISSET_FLAG_PUSH(p) ((p)->tcph->th_flags & TH_PUSH)
- #define TCP_ISSET_FLAG_ACK(p) ((p)->tcph->th_flags & TH_ACK)
- #define TCP_ISSET_FLAG_URG(p) ((p)->tcph->th_flags & TH_URG)
- #define TCP_ISSET_FLAG_RES2(p) ((p)->tcph->th_flags & TH_RES2)
- #define TCP_ISSET_FLAG_RES1(p) ((p)->tcph->th_flags & TH_RES1)
- typedef struct TCPOpt_ {
- uint8_t type;
- uint8_t len;
- uint8_t *data;
- } TCPOpt;
- typedef struct TCPOptSackRecord_ {
- uint32_t le; /**< left edge, network order */
- uint32_t re; /**< right edge, network order */
- } TCPOptSackRecord;
- typedef struct TCPHdr_
- {
- uint16_t th_sport; /**< source port */
- uint16_t th_dport; /**< destination port */
- uint32_t th_seq; /**< sequence number */
- uint32_t th_ack; /**< acknowledgement number */
- uint8_t th_offx2; /**< offset and reserved */
- uint8_t th_flags; /**< pkt flags */
- uint16_t th_win; /**< pkt window */
- uint16_t th_sum; /**< checksum */
- uint16_t th_urp; /**< urgent pointer */
- } TCPHdr;
- typedef struct TCPVars_
- {
- /* checksum computed over the tcp(for both ipv4 and ipv6) packet */
- int32_t comp_csum;
- uint8_t tcp_opt_cnt;
- TCPOpt tcp_opts[TCP_OPTMAX];
- /* ptrs to commonly used and needed opts */
- TCPOpt *ts;
- TCPOpt *sack;
- TCPOpt *sackok;
- TCPOpt *ws;
- TCPOpt *mss;
- } TCPVars;
- #define CLEAR_TCP_PACKET(p) { \
- (p)->tcph = NULL; \
- (p)->tcpvars.comp_csum = -1; \
- (p)->tcpvars.tcp_opt_cnt = 0; \
- (p)->tcpvars.ts = NULL; \
- (p)->tcpvars.sack = NULL; \
- (p)->tcpvars.sackok = NULL; \
- (p)->tcpvars.ws = NULL; \
- (p)->tcpvars.mss = NULL; \
- }
- void DecodeTCPRegisterTests(void);
- /** -------- Inline functions ------- */
- static inline uint16_t TCPCalculateChecksum(uint16_t *, uint16_t *, uint16_t);
- static inline uint16_t TCPV6CalculateChecksum(uint16_t *, uint16_t *, uint16_t);
- /**
- * \brief Calculates the checksum for the TCP packet
- *
- * \param shdr Pointer to source address field from the IP packet. Used as a
- * part of the pseudoheader for computing the checksum
- * \param pkt Pointer to the start of the TCP packet
- * \param tlen Total length of the TCP packet(header + payload)
- *
- * \retval csum Checksum for the TCP packet
- */
- static inline uint16_t TCPCalculateChecksum(uint16_t *shdr, uint16_t *pkt,
- uint16_t tlen)
- {
- uint16_t pad = 0;
- uint32_t csum = shdr[0];
- csum += shdr[1] + shdr[2] + shdr[3] + htons(6) + htons(tlen);
- csum += pkt[0] + pkt[1] + pkt[2] + pkt[3] + pkt[4] + pkt[5] + pkt[6] +
- pkt[7] + pkt[9];
- tlen -= 20;
- pkt += 10;
- while (tlen >= 32) {
- csum += pkt[0] + pkt[1] + pkt[2] + pkt[3] + pkt[4] + pkt[5] + pkt[6] +
- pkt[7] + pkt[8] + pkt[9] + pkt[10] + pkt[11] + pkt[12] + pkt[13] +
- pkt[14] + pkt[15];
- tlen -= 32;
- pkt += 16;
- }
- while(tlen >= 8) {
- csum += pkt[0] + pkt[1] + pkt[2] + pkt[3];
- tlen -= 8;
- pkt += 4;
- }
- while(tlen >= 4) {
- csum += pkt[0] + pkt[1];
- tlen -= 4;
- pkt += 2;
- }
- while (tlen > 1) {
- csum += pkt[0];
- pkt += 1;
- tlen -= 2;
- }
- if (tlen == 1) {
- *(uint8_t *)(&pad) = (*(uint8_t *)pkt);
- csum += pad;
- }
- csum = (csum >> 16) + (csum & 0x0000FFFF);
- csum += (csum >> 16);
- return (uint16_t)~csum;
- }
- /**
- * \brief Calculates the checksum for the TCP packet
- *
- * \param shdr Pointer to source address field from the IPV6 packet. Used as a
- * part of the psuedoheader for computing the checksum
- * \param pkt Pointer to the start of the TCP packet
- * \param tlen Total length of the TCP packet(header + payload)
- *
- * \retval csum Checksum for the TCP packet
- */
- static inline uint16_t TCPV6CalculateChecksum(uint16_t *shdr, uint16_t *pkt,
- uint16_t tlen)
- {
- uint16_t pad = 0;
- uint32_t csum = shdr[0];
- csum += shdr[1] + shdr[2] + shdr[3] + shdr[4] + shdr[5] + shdr[6] +
- shdr[7] + shdr[8] + shdr[9] + shdr[10] + shdr[11] + shdr[12] +
- shdr[13] + shdr[14] + shdr[15] + htons(6) + htons(tlen);
- csum += pkt[0] + pkt[1] + pkt[2] + pkt[3] + pkt[4] + pkt[5] + pkt[6] +
- pkt[7] + pkt[9];
- tlen -= 20;
- pkt += 10;
- while (tlen >= 32) {
- csum += pkt[0] + pkt[1] + pkt[2] + pkt[3] + pkt[4] + pkt[5] + pkt[6] +
- pkt[7] + pkt[8] + pkt[9] + pkt[10] + pkt[11] + pkt[12] + pkt[13] +
- pkt[14] + pkt[15];
- tlen -= 32;
- pkt += 16;
- }
- while(tlen >= 8) {
- csum += pkt[0] + pkt[1] + pkt[2] + pkt[3];
- tlen -= 8;
- pkt += 4;
- }
- while(tlen >= 4) {
- csum += pkt[0] + pkt[1];
- tlen -= 4;
- pkt += 2;
- }
- while (tlen > 1) {
- csum += pkt[0];
- pkt += 1;
- tlen -= 2;
- }
- if (tlen == 1) {
- *(uint8_t *)(&pad) = (*(uint8_t *)pkt);
- csum += pad;
- }
- csum = (csum >> 16) + (csum & 0x0000FFFF);
- csum += (csum >> 16);
- return (uint16_t)~csum;
- }
- #endif /* __DECODE_TCP_H__ */