/* 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 "util-pool-thread.h" #include "util-streaming-buffer.h" #define STREAMTCP_QUEUE_FLAG_TS 0x01 #define STREAMTCP_QUEUE_FLAG_WS 0x02 #define STREAMTCP_QUEUE_FLAG_SACK 0x04 /** Tracking SYNs and SYN/ACKs */ 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 */ RB_ENTRY(StreamTcpSackRecord) rb; } StreamTcpSackRecord; int TcpSackCompare(struct StreamTcpSackRecord *a, struct StreamTcpSackRecord *b); /* red-black tree prototype for SACK records */ RB_HEAD(TCPSACK, StreamTcpSackRecord); RB_PROTOTYPE(TCPSACK, StreamTcpSackRecord, rb, TcpSackCompare); #define TCPSEG_PKT_HDR_DEFAULT_SIZE 64 /* * Struct to add the additional information required to use TcpSegments to dump * a packet capture to file with the stream-pcap-log output option. This is only * used if the session-dump option is enabled. */ typedef struct TcpSegmentPcapHdrStorage_ { struct timeval ts; uint32_t pktlen; uint32_t alloclen; uint8_t *pkt_hdr; } TcpSegmentPcapHdrStorage; typedef struct TcpSegment { PoolThreadId pool_id; uint16_t payload_len; /**< actual size of the payload */ uint32_t seq; RB_ENTRY(TcpSegment) __attribute__((__packed__)) rb; StreamingBufferSegment sbseg; TcpSegmentPcapHdrStorage *pcap_hdr_storage; } __attribute__((__packed__)) TcpSegment; /** \brief compare function for the Segment tree * * Main sort point is the sequence number. When sequence numbers * are equal compare payload_len as well. This way the tree is * sorted by seq, and in case of duplicate seqs we are sorted * small to large. */ int TcpSegmentCompare(struct TcpSegment *a, struct TcpSegment *b); /* red-black tree prototype for TcpSegment */ RB_HEAD(TCPSEG, TcpSegment); RB_PROTOTYPE(TCPSEG, TcpSegment, rb, TcpSegmentCompare); #define TCP_SEG_LEN(seg) (seg)->payload_len #define TCP_SEG_OFFSET(seg) (seg)->sbseg.stream_offset #define SEG_SEQ_RIGHT_EDGE(seg) ((seg)->seq + TCP_SEG_LEN((seg))) /* get right edge of sequence space of seen segments. * Only use if STREAM_HAS_SEEN_DATA is true. */ #define STREAM_SEQ_RIGHT_EDGE(stream) (stream)->segs_right_edge #define STREAM_RIGHT_EDGE(stream) (STREAM_BASE_OFFSET((stream)) + (STREAM_SEQ_RIGHT_EDGE((stream)) - (stream)->base_seq)) /* return true if we have seen data. */ #define STREAM_HAS_SEEN_DATA(stream) StreamingBufferHasData(&(stream)->sb) 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 base_seq; /**< seq where we are left with reassembly. Matches STREAM_BASE_OFFSET below. */ uint32_t app_progress_rel; /**< app-layer progress relative to STREAM_BASE_OFFSET */ uint32_t raw_progress_rel; /**< raw reassembly progress relative to STREAM_BASE_OFFSET */ uint32_t log_progress_rel; /**< streaming logger progress relative to STREAM_BASE_OFFSET */ uint32_t min_inspect_depth; /**< min inspect size set by the app layer, to make sure enough data * remains available for inspection together with app layer buffers */ uint32_t data_required; /**< data required from STREAM_APP_PROGRESS before calling app-layer again */ StreamingBuffer sb; struct TCPSEG seg_tree; /**< red black tree of TCP segments. Data is stored in TcpStream::sb */ uint32_t segs_right_edge; uint32_t sack_size; /**< combined size of the SACK ranges currently in our tree. Updated * at INSERT/REMOVE time. */ struct TCPSACK sack_tree; /**< red back tree of TCP SACK records. */ } TcpStream; #define STREAM_BASE_OFFSET(stream) ((stream)->sb.region.stream_offset) #define STREAM_APP_PROGRESS(stream) (STREAM_BASE_OFFSET((stream)) + (stream)->app_progress_rel) #define STREAM_RAW_PROGRESS(stream) (STREAM_BASE_OFFSET((stream)) + (stream)->raw_progress_rel) #define STREAM_LOG_PROGRESS(stream) (STREAM_BASE_OFFSET((stream)) + (stream)->log_progress_rel) /* from /usr/include/netinet/tcp.h */ enum TcpState { TCP_NONE = 0, // TCP_LISTEN = 1, TCP_SYN_SENT = 2, TCP_SYN_RECV = 3, TCP_ESTABLISHED = 4, TCP_FIN_WAIT1 = 5, TCP_FIN_WAIT2 = 6, TCP_TIME_WAIT = 7, TCP_LAST_ACK = 8, TCP_CLOSE_WAIT = 9, TCP_CLOSING = 10, TCP_CLOSED = 11, }; /* * Per SESSION flags */ /** Flag for mid stream session */ #define STREAMTCP_FLAG_MIDSTREAM BIT_U32(0) /** Flag for mid stream established session */ #define STREAMTCP_FLAG_MIDSTREAM_ESTABLISHED BIT_U32(1) /** Flag for mid session when syn/ack is received */ #define STREAMTCP_FLAG_MIDSTREAM_SYNACK BIT_U32(2) /** Flag for TCP Timestamp option */ #define STREAMTCP_FLAG_TIMESTAMP BIT_U32(3) /** Server supports wscale (even though it can be 0) */ #define STREAMTCP_FLAG_SERVER_WSCALE BIT_U32(4) /** Closed by RST */ #define STREAMTCP_FLAG_CLOSED_BY_RST BIT_U32(5) /** Flag to indicate that the session is handling asynchronous stream.*/ #define STREAMTCP_FLAG_ASYNC BIT_U32(6) /** 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 BIT_U32(7) /** 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 BIT_U32(8) /** Flag to indicate the client (SYN pkt) permits SACK */ #define STREAMTCP_FLAG_CLIENT_SACKOK BIT_U32(9) /** Flag to indicate both sides of the session permit SACK (SYN + SYN/ACK) */ #define STREAMTCP_FLAG_SACKOK BIT_U32(10) /** Session is in "lossy" state, be liberal */ #define STREAMTCP_FLAG_LOSSY_BE_LIBERAL BIT_U32(11) /** 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 BIT_U32(12) /** App Layer tracking/reassembly is disabled */ #define STREAMTCP_FLAG_APP_LAYER_DISABLED BIT_U32(13) /** Stream can be bypass */ #define STREAMTCP_FLAG_BYPASS BIT_U32(14) /** SSN uses TCP Fast Open */ #define STREAMTCP_FLAG_TCP_FAST_OPEN BIT_U32(15) /** SYN/ACK ignored the data while ACKing the SYN */ #define STREAMTCP_FLAG_TFO_DATA_IGNORED BIT_U32(16) /* zero window probe */ #define STREAMTCP_FLAG_ZWP_TS BIT_U32(17) #define STREAMTCP_FLAG_ZWP_TC BIT_U32(18) /* * Per STREAM flags */ /** Flag to indicate that we have seen gap on the stream */ #define STREAMTCP_STREAM_FLAG_HAS_GAP BIT_U16(0) /** Flag to avoid stream reassembly/app layer inspection for the stream */ #define STREAMTCP_STREAM_FLAG_NOREASSEMBLY BIT_U16(1) /** we received a keep alive */ #define STREAMTCP_STREAM_FLAG_KEEPALIVE BIT_U16(2) /** Stream has reached it's reassembly depth, all further packets are ignored */ #define STREAMTCP_STREAM_FLAG_DEPTH_REACHED BIT_U16(3) /** Trigger reassembly next time we need 'raw' */ #define STREAMTCP_STREAM_FLAG_TRIGGER_RAW BIT_U16(4) /** Stream supports TIMESTAMP -- used to set ssn STREAMTCP_FLAG_TIMESTAMP * flag. */ #define STREAMTCP_STREAM_FLAG_TIMESTAMP BIT_U16(5) /** Flag to indicate the zero value of timestamp */ #define STREAMTCP_STREAM_FLAG_ZERO_TIMESTAMP BIT_U16(6) /** App proto detection completed */ #define STREAMTCP_STREAM_FLAG_APPPROTO_DETECTION_COMPLETED BIT_U16(7) /** App proto detection skipped */ #define STREAMTCP_STREAM_FLAG_APPPROTO_DETECTION_SKIPPED BIT_U16(8) /** Raw reassembly disabled for new segments */ #define STREAMTCP_STREAM_FLAG_NEW_RAW_DISABLED BIT_U16(9) /** Raw reassembly disabled completely */ #define STREAMTCP_STREAM_FLAG_DISABLE_RAW BIT_U16(10) #define STREAMTCP_STREAM_FLAG_RST_RECV BIT_U16(11) /** NOTE: flags field is 12 bits */ #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 SEQ_MIN(a, b) (SEQ_LT((a), (b)) ? (a) : (b)) #define SEQ_MAX(a, b) (SEQ_GT((a), (b)) ? (a) : (b)) #define STREAMTCP_SET_RA_BASE_SEQ(stream, seq) { \ do { \ (stream)->base_seq = (seq) + 1; \ } while(0); \ } #define StreamTcpSetEvent(p, e) \ { \ if ((p)->flags & PKT_STREAM_NO_EVENTS) { \ SCLogDebug("not setting event %d on pkt %p (%" PRIu64 "), " \ "stream in known bad condition", \ (e), p, (p)->pcap_cnt); \ } else { \ SCLogDebug("setting event %d on pkt %p (%" PRIu64 ")", (e), p, (p)->pcap_cnt); \ ENGINE_SET_EVENT((p), (e)); \ p->tcpvars.stream_pkt_flags |= STREAM_PKT_FLAG_EVENTSET; \ } \ } typedef struct TcpSession_ { PoolThreadId pool_id; uint8_t state:4; /**< tcp state from state enum */ uint8_t pstate:4; /**< previous 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 */ uint32_t flags; uint32_t reassembly_depth; /**< reassembly depth for the stream */ TcpStream server; TcpStream client; 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); #define STREAM_PKT_FLAG_RETRANSMISSION BIT_U16(0) #define STREAM_PKT_FLAG_SPURIOUS_RETRANSMISSION BIT_U16(1) #define STREAM_PKT_FLAG_STATE_UPDATE BIT_U16(2) #define STREAM_PKT_FLAG_KEEPALIVE BIT_U16(3) #define STREAM_PKT_FLAG_KEEPALIVEACK BIT_U16(4) #define STREAM_PKT_FLAG_WINDOWUPDATE BIT_U16(5) #define STREAM_PKT_FLAG_EVENTSET BIT_U16(6) #define STREAM_PKT_FLAG_DUP_ACK BIT_U16(7) #define STREAM_PKT_FLAG_DSACK BIT_U16(8) #define STREAM_PKT_FLAG_ACK_UNSEEN_DATA BIT_U16(9) #define STREAM_PKT_FLAG_TCP_PORT_REUSE BIT_U16(10) #define STREAM_PKT_FLAG_TCP_ZERO_WIN_PROBE BIT_U16(11) #define STREAM_PKT_FLAG_TCP_ZERO_WIN_PROBE_ACK BIT_U16(12) #define STREAM_PKT_FLAG_SET(p, f) (p)->tcpvars.stream_pkt_flags |= (f) #endif /* __STREAM_TCP_PRIVATE_H__ */