uc-tcp.rar_uc/tcp-ip

/***************************************************************************** * 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 (please don't use tabs!) * *(yyyy-mm-dd) * 1998-02-02 Guy Lancaster <glanca@gesn.com>, Global Election Systems Inc. * Original based on ka9q and BSD codes. * 2001-05-18 Mads Christiansen <mads@mogi.dk>, Partner Voxtream * Added support for running uC/IP in a single proces and on ethernet. * Bugfix in resendTimeout, diffTime -> diffJTime! * 2001-06-07 Robert Dickenson <odin@pnc.com.au>, Cognizant Pty Ltd. * Quick fix to tcpInput for when OSSemCreate hadn't been called. * ****************************************************************************** * 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 "netconf.h" #include <string.h> #include "net.h" #include "nettimer.h" #include "netbuf.h" #if MD5_SUPPORT > 0 #include "netrand.h" #endif #include "netmagic.h" //#include "devio.h" #include "netip.h" #include "netiphdr.h" #include "nettcp.h" #include "nettcphd.h" #include <stdio.h> #include "netdebug.h" #include "netos.h" #pragma warning (push) #pragma warning (disable: 4761) // integral size mismatch in argument; conversion supplied #pragma warning (disable: 4018) // signed/unsigned mismatch /*************************/ /*** LOCAL DEFINITIONS ***/ /*************************/ /* Configuration */ #define MAXTCP 12 /* 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 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 { u_int32_t una; /* First unacknowledged sequence number */ u_int32_t nxt; /* Next sequence num to be sent for the first time */ u_int32_t ptr; /* Working transmission pointer */ u_int16_t wnd; /* Other end's offered receive window */ u_int32_t wl1; /* Sequence number used for last window update */ u_int32_t wl2; /* Ack number used for last window update */ } snd; u_int32_t iss; /* Initial send sequence number */ u_int16_t cwind; /* Congestion window */ u_int16_t ssthresh; /* Slow-start threshold */ u_int32_t resent; /* Count of bytes retransmitted */ /* Receive sequence variables */ struct { u_int32_t nxt; /* Incoming sequence number expected next */ // u_int16_t wnd; /* Our offered receive window */ short wnd; /* Our offered receive window */ u_int16_t up; /* Receive urgent pointer */ } rcv; u_int32_t irs; /* Initial receive sequence number */ u_int16_t mss; /* Maximum segment size */ u_int32_t 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 +