uCOS-net-1.0.rar_UCys.Net_ucos_ucos net

/***************************************************************************** * nettcp.c - Network Transport Control Protocol program file. * * Copyright (c) 1998 by Global Election Systems Inc. All rights reserved. * * The authors hereby grant permission to use, copy, modify, distribute, * and license this software and its documentation for any purpose, provided * that existing copyright notices are retained in all copies and that this * notice and the following disclaimer are included verbatim in any * distributions. No written agreement, license, or royalty fee is required * for any of the authorized uses. * * THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS *AS IS* AND ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * ****************************************************************************** * REVISION HISTORY * * 98-02-02 Guy Lancaster <[email protected]>, Global Election Systems Inc. * Original based on ka9q and BSD codes. ****************************************************************************** * NOTES * * MAXIMUM WINDOW * We use a signed short int for the segment size adjustment (trimSeg()) to * allow returning error codes. Thus our maximum segment size must be <= * INT_MAX (i.e. 32767) rather than MAX_UINT. This is not a problem * considering that we are using a PPP link over a serial link. * * HEADER CACHE * The header values are all loaded in the header caches before being * written to the outgoing segment so that a debugger can see the values * of the header last sent. ****************************************************************************** * TO DO * * - Implement a SENDFIN flag in the tcb flags and use it in tcpOutput(). * - FINISH close! *****************************************************************************/ #include "typedefs.h" #include "avconfig.h" #include <string.h> #include "stdio.h" // Required for debug.h #include "timer.h" #include "avos.h" #include "netbuf.h" #include "devio.h" #include "net.h" #include "netmagic.h" #include "netip.h" #include "netiphdr.h" #include "nettcp.h" #include "nettcphd.h" #include "debug.h" /*************************/ /*** LOCAL DEFINITIONS ***/ /*************************/ /* Configuration */ #define MAXTCP 6 /* Maximum TCP connections incl listeners. */ #define TCPTTL 64 /* Default time-to-live for TCP datagrams. */ #define OPTSPACE 5*4 /* TCP options space - must be a multiple of 4. */ #define NTCB 16 /* # TCB hash table headers */ #define MAXRETRANS 12 /* Maximum retransmissions. */ #define MAXKEEPTIMES 10 /* Maximum keep alive probe timeouts. */ #define MAXLISTEN 2 /* Maximum queued cloned listen connections. */ #define MAXFINWAIT2 600L /* Max time in seconds to wait for peer FIN. */ #define WRITESLEEP TICKSPERSEC /* Sleep time write waits for buffers (jiffies). */ #define STACK_SIZE NETSTACK /* Minimal stack. */ /* * TCP connection control flag masks. */ #define FORCE 1 /* We owe the other end an ACK or window update */ #define CLONE 2 /* Server-type TCB, cloned on incoming SYN */ #define RETRAN 4 /* A retransmission has occurred */ #define ACTIVE 8 /* TCB created with an active open */ #define SYNACK 16 /* Our SYN has been acked */ #define KEEPALIVE 32 /* Send a keepalive probe */ /* Round trip timing parameters */ #define AGAIN 8 /* Average RTT gain = 1/8 */ #define DGAIN 4 /* Mean deviation gain = 1/4 */ #define MSL2 30 /* Guess at two maximum-segment lifetimes in seconds */ /* procInFlags return codes. */ #define ACKOK 0 /* OK to process segment. */ #define ACKDROP -1 /* Drop the segment. */ #define ACKRESET -2 /* Return segment as a reset. */ #define ACKCLOSE -3 /* Close the connection. */ /************************/ /*** LOCAL DATA TYPES ***/ /************************/ /* * Combined TCP/IP headers with no options. Used to cached the headers. */ typedef struct TcpIPHdr_s { IPHdr ipHdr; /* IP header - no options. */ TCPHdr tcpHdr; /* TCP header. tcpSeq, ack, off, & win * are in host byte order. */ char options[OPTSPACE]; /* Cache for TCP options. */ } TCPIPHdr; /* * TCP connection states. */ typedef enum { CLOSED = 0, /* Must be 0 */ LISTEN = 1, SYN_SENT= 2, SYN_RECEIVED = 3, ESTABLISHED = 4, FINWAIT1 = 5, FINWAIT2 = 6, CLOSE_WAIT = 7, CLOSING = 8, LAST_ACK = 9, TIME_WAIT = 10 } TCPState; /* * TCP session close reason codes. */ typedef enum { NORMAL = 0, /* Normal close */ RESET = 1, /* Reset by other end */ TIMEOUT = 2, /* Excessive retransmissions */ NETWORK = 3 /* Network problem (ICMP message) */ } TCPReason; /* * TCP connection control block. */ typedef struct TCPCB_s { struct TCPCB_s *prev; /* Linked list pointers for hash table */ struct TCPCB_s *next; Connection conn; /* Connection struct for hash lookup. */ TCPState state; /* Connection state */ int freeOnClose; /* Flag set to free TCB on close. */ int closeReason; /* Reason for closing - TCPERR_ or 0 */ int traceLevel; /* Trace level this connection. */ /* * Send sequence variables. */ struct { int32 una; /* First unacknowledged sequence number */ int32 nxt; /* Next sequence num to be sent for the first time */ int32 ptr; /* Working transmission pointer */ int16 wnd; /* Other end's offered receive window */ int32 wl1; /* Sequence number used for last window update */ int32 wl2; /* Ack number used for last window update */ } snd; int32 iss; /* Initial send sequence number */ int16 cwind; /* Congestion window */ int16 ssthresh; /* Slow-start threshold */ int32 resent; /* Count of bytes retransmitted */ /* Receive sequence variables */ struct { int32 nxt; /* Incoming sequence number expected next */ int16 wnd; /* Our offered receive window */ int16 up; /* Receive urgent pointer */ } rcv; int32 irs; /* Initial receive sequence number */ int16 mss; /* Maximum segment size */ int32 rerecv; /* Count of duplicate bytes received */ int minFreeBufs; /* Minimum free buffers before we'll queue something. */ char backoff; /* Backoff interval */ char flags; /* Control flags */ int listenQOpen; /* Max queued listen connections. */ int listenQHead; /* Head of cloned TCB queue. */ int listenQTail; /* Tail of cloned TCB queue. */ struct TCPCB_s *listenQ[MAXLISTEN + 1]; /* Circular queue of clones. */ NBufQHdr rcvq; /* Receive queue */ int16 rcvcnt; /* Bytes on receive queue. */ NBuf *rcvBuf; /* Hold one buffer while we trim it. */ NBufQHdr sndq; /* Send queue */ int16 sndcnt; /* Number of unacknowledged sequence numbers on * send queue. NB: includes SYN and FIN, which don't * actually appear on sndq! */ NBufQHdr *reseq; /* Out-of-order segment queue */ Timer resendTimer; /* Timeout timer */ u_int32 retransTime; /* Retransmission time - 0 for none. */ u_int retransCnt; /* Retransmission count at current wl2. */ u_int32 rttStart; /* Start time for round trip measurement. */ int32 rttseq; /* Sequence number being timed */ int32 srtt; /* Smoothed round trip time, milliseconds */ int32 mdev; /* Mean deviation, milliseconds */ u_long keepAlive; /* Keepalive in Jiffys - 0 fo