/* 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 */ #ifndef __STREAM_TCP_PRIVATE_H__ #define __STREAM_TCP_PRIVATE_H__ #include "decode.h" #include "util-pool.h" #include "util-pool-thread.h" #define STREAMTCP_QUEUE_FLAG_TS 0x01 #define STREAMTCP_QUEUE_FLAG_WS 0x02 #define STREAMTCP_QUEUE_FLAG_SACK 0x04 /** currently only SYN/ACK */ typedef struct TcpStateQueue_ { uint8_t flags; uint8_t wscale; uint16_t win; uint32_t seq; uint32_t ack; uint32_t ts; uint32_t pkt_ts; struct TcpStateQueue_ *next; } TcpStateQueue; typedef struct StreamTcpSackRecord_ { uint32_t le; /**< left edge, host order */ uint32_t re; /**< right edge, host order */ struct StreamTcpSackRecord_ *next; } StreamTcpSackRecord; typedef struct TcpSegment_ { uint8_t *payload; uint16_t payload_len; /**< actual size of the payload */ uint16_t pool_size; /**< size of the memory */ uint32_t seq; struct TcpSegment_ *next; struct TcpSegment_ *prev; /* coccinelle: TcpSegment:flags:SEGMENTTCP_FLAG */ uint8_t flags; } TcpSegment; typedef struct TcpStream_ { uint16_t flags:12; /**< Flag specific to the stream e.g. Timestamp */ /* coccinelle: TcpStream:flags:STREAMTCP_STREAM_FLAG_ */ uint16_t wscale:4; /**< wscale setting in this direction, 4 bits as max val is 15 */ uint8_t os_policy; /**< target based OS policy used for reassembly and handling packets*/ uint8_t tcp_flags; /**< TCP flags seen */ uint32_t isn; /**< initial sequence number */ uint32_t next_seq; /**< next expected sequence number */ uint32_t last_ack; /**< last ack'd sequence number in this stream */ uint32_t next_win; /**< next max seq within window */ uint32_t window; /**< current window setting, after wscale is applied */ uint32_t last_ts; /**< Time stamp (TSVAL) of the last seen packet for this stream*/ uint32_t last_pkt_ts; /**< Time of last seen packet for this stream (needed for PAWS update) This will be used to validate the last_ts, when connection has been idle for longer time.(RFC 1323)*/ /* reassembly */ uint32_t ra_app_base_seq; /**< reassembled seq. We've reassembled up to this point. */ uint32_t ra_raw_base_seq; /**< reassembled seq. We've reassembled up to this point. */ TcpSegment *seg_list; /**< list of TCP segments that are not yet (fully) used in reassembly */ TcpSegment *seg_list_tail; /**< Last segment in the reassembled stream seg list*/ StreamTcpSackRecord *sack_head; /**< head of list of SACK records */ StreamTcpSackRecord *sack_tail; /**< tail of list of SACK records */ } TcpStream; /* from /usr/include/netinet/tcp.h */ enum { TCP_NONE, TCP_LISTEN, TCP_SYN_SENT, TCP_SYN_RECV, TCP_ESTABLISHED, TCP_FIN_WAIT1, TCP_FIN_WAIT2, TCP_TIME_WAIT, TCP_LAST_ACK, TCP_CLOSE_WAIT, TCP_CLOSING, TCP_CLOSED, }; /* * Per SESSION flags */ /** Flag for mid stream session */ #define STREAMTCP_FLAG_MIDSTREAM 0x0001 /** Flag for mid stream established session */ #define STREAMTCP_FLAG_MIDSTREAM_ESTABLISHED 0x0002 /** Flag for mid session when syn/ack is received */ #define STREAMTCP_FLAG_MIDSTREAM_SYNACK 0x0004 /** Flag for TCP Timestamp option */ #define STREAMTCP_FLAG_TIMESTAMP 0x0008 /** Server supports wscale (even though it can be 0) */ #define STREAMTCP_FLAG_SERVER_WSCALE 0x0010 /** 'Raw' reassembly is disabled for this ssn. */ #define STREAMTCP_FLAG_DISABLE_RAW 0x0020 /** Flag to indicate that the session is handling asynchronous stream.*/ #define STREAMTCP_FLAG_ASYNC 0x0040 /** Flag to indicate we're dealing with 4WHS: SYN, SYN, SYN/ACK, ACK * (http://www.breakingpointsystems.com/community/blog/tcp-portals-the-three-way-handshake-is-a-lie) */ #define STREAMTCP_FLAG_4WHS 0x0080 /** Flag to indicate that this session is possible trying to evade the detection * (http://www.packetstan.com/2010/06/recently-ive-been-on-campaign-to-make.html) */ #define STREAMTCP_FLAG_DETECTION_EVASION_ATTEMPT 0x0100 /** Flag to indicate the client (SYN pkt) permits SACK */ #define STREAMTCP_FLAG_CLIENT_SACKOK 0x0200 /** Flag to indicate both sides of the session permit SACK (SYN + SYN/ACK) */ #define STREAMTCP_FLAG_SACKOK 0x0400 /** Flag for triggering RAW reassembly before the size limit is reached or the stream reaches EOF. */ #define STREAMTCP_FLAG_TRIGGER_RAW_REASSEMBLY 0x0800 /** 3WHS confirmed by server -- if suri sees 3whs ACK but server doesn't (pkt * is lost on the way to server), SYN/ACK is retransmitted. If server sends * normal packet we assume 3whs to be completed. Only used for SYN/ACK resend * event. */ #define STREAMTCP_FLAG_3WHS_CONFIRMED 0x1000 /** App Layer tracking/reassembly is disabled */ #define STREAMTCP_FLAG_APP_LAYER_DISABLED 0x2000 /* * Per STREAM flags */ /** stream is in a gap state */ #define STREAMTCP_STREAM_FLAG_GAP 0x0001 /** Flag to avoid stream reassembly/app layer inspection for the stream */ #define STREAMTCP_STREAM_FLAG_NOREASSEMBLY 0x0002 /** we received a keep alive */ #define STREAMTCP_STREAM_FLAG_KEEPALIVE 0x0004 /** Stream has reached it's reassembly depth, all further packets are ignored */ #define STREAMTCP_STREAM_FLAG_DEPTH_REACHED 0x0008 // vacancy /** Stream supports TIMESTAMP -- used to set ssn STREAMTCP_FLAG_TIMESTAMP * flag. */ #define STREAMTCP_STREAM_FLAG_TIMESTAMP 0x0020 /** Flag to indicate the zero value of timestamp */ #define STREAMTCP_STREAM_FLAG_ZERO_TIMESTAMP 0x0040 /** App proto detection completed */ #define STREAMTCP_STREAM_FLAG_APPPROTO_DETECTION_COMPLETED 0x0080 /** App proto detection skipped */ #define STREAMTCP_STREAM_FLAG_APPPROTO_DETECTION_SKIPPED 0x0100 /** Raw reassembly disabled for new segments */ #define STREAMTCP_STREAM_FLAG_NEW_RAW_DISABLED 0x0200 // vacancy 2x /** NOTE: flags field is 12 bits */ /* * Per SEGMENT flags */ /** Flag to indicate that the current segment has been processed by the * reassembly code and should be deleted after app layer protocol has been * detected. */ #define SEGMENTTCP_FLAG_RAW_PROCESSED 0x01 /** App Layer reassembly code is done with this segment */ #define SEGMENTTCP_FLAG_APPLAYER_PROCESSED 0x02 /** Log API (streaming) has processed this segment */ #define SEGMENTTCP_FLAG_LOGAPI_PROCESSED 0x04 #define PAWS_24DAYS 2073600 /**< 24 days in seconds */ #define PKT_IS_IN_RIGHT_DIR(ssn, p) ((ssn)->flags & STREAMTCP_FLAG_MIDSTREAM_SYNACK ? \ PKT_IS_TOSERVER(p) ? (p)->flowflags &= ~FLOW_PKT_TOSERVER \ (p)->flowflags |= FLOW_PKT_TOCLIENT : (p)->flowflags &= ~FLOW_PKT_TOCLIENT \ (p)->flowflags |= FLOW_PKT_TOSERVER : 0) /* Macro's for comparing Sequence numbers * Page 810 from TCP/IP Illustrated, Volume 2. */ #define SEQ_EQ(a,b) ((int32_t)((a) - (b)) == 0) #define SEQ_LT(a,b) ((int32_t)((a) - (b)) < 0) #define SEQ_LEQ(a,b) ((int32_t)((a) - (b)) <= 0) #define SEQ_GT(a,b) ((int32_t)((a) - (b)) > 0) #define SEQ_GEQ(a,b) ((int32_t)((a) - (b)) >= 0) #define STREAMTCP_SET_RA_BASE_SEQ(stream, seq) { \ do { \ (stream)->ra_raw_base_seq = (seq); \ (stream)->ra_app_base_seq = (seq); \ } while(0); \ } #define StreamTcpSetEvent(p, e) { \ SCLogDebug("setting event %"PRIu8" on pkt %p (%"PRIu64")", (e), p, (p)->pcap_cnt); \ ENGINE_SET_EVENT((p), (e)); \ } typedef struct TcpSession_ { PoolThreadReserved res; uint8_t state; uint8_t queue_len; /**< length of queue list below */ int8_t data_first_seen_dir; /** track all the tcp flags we've seen */ uint8_t tcp_packet_flags; /* coccinelle: TcpSession:flags:STREAMTCP_FLAG */ uint16_t flags; TcpStream server; TcpStream client; struct StreamMsg_ *toserver_smsg_head; /**< list of stream msgs (for detection inspection) */ struct StreamMsg_ *toserver_smsg_tail; /**< list of stream msgs (for detection inspection) */ struct StreamMsg_ *toclient_smsg_head; /**< list of stream msgs (for detection inspection) */ struct StreamMsg_ *toclient_smsg_tail; /**< list of stream msgs (for detection inspection) */ TcpStateQueue *queue; /**< list of SYN/ACK candidates */ } TcpSession; #define StreamTcpSetStreamFlagAppProtoDetectionCompleted(stream) \ ((stream)->flags |= STREAMTCP_STREAM_FLAG_APPPROTO_DETECTION_COMPLETED) #define StreamTcpIsSetStreamFlagAppProtoDetectionCompleted(stream) \ ((stream)->flags & STREAMTCP_STREAM_FLAG_APPPROTO_DETECTION_COMPLETED) #define StreamTcpResetStreamFlagAppProtoDetectionCompleted(stream) \ ((stream)->flags &= ~STREAMTCP_STREAM_FLAG_APPPROTO_DETECTION_COMPLETED); #define StreamTcpDisableAppLayerReassembly(ssn) do { \ SCLogDebug("setting STREAMTCP_FLAG_APP_LAYER_DISABLED on ssn %p", ssn); \ ((ssn)->flags |= STREAMTCP_FLAG_APP_LAYER_DISABLED); \ } while (0); #endif /* __STREAM_TCP_PRIVATE_H__ */