devip: improve tcp error handling for ipoput
The ipoput4() and ipoput6() functions can raise an error(), which means before calling sndrst() or limbo() (from tcpiput()), we have to get rid of our blist by calling freeblist(bp). Makse sure to set the Block pointer to nil after freeing in ipiput() to avoid accidents. Fix wrong panic string in sndsynack, and make any sending functions like sndrst(), sndsynack() and tcpsendka() return the value of ipoput*(), so we can distinguish "no route" error. Add a Enoroute[] string constant. Both htontcp4() and htontcp6() can never return nil, as they will allocate new or resize the existing block. Remove the misleading error handling code that assumes that it can fail. Unlock proto on error in limborexmit() which can be raised from sndsynack() -> ipoput*() -> error(). Make sndsynack() pass a Routehint pointer to ipoput*() as it already did the route lookup, so we dont have todo it twice.
This commit is contained in:
cinap_lenrek
parent
ad1ab7089d
commit
b51d7ca3ba
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@ -90,8 +90,11 @@ enum
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Defadvscale = 4, /* default advertisement */
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};
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/* negative return from ipoput means no route */
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static char Enoroute[] = "no route";
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/* Must correspond to the enumeration above */
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char *tcpstates[] =
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static char *tcpstates[] =
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{
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"Closed", "Listen", "Syn_sent", "Syn_received",
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"Established", "Finwait1", "Finwait2", "Close_wait",
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@ -405,7 +408,7 @@ struct Tcppriv
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*/
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int tcpporthogdefense = 0;
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static int addreseq(Fs*, Tcpctl*, Tcppriv*, Tcp*, Block*, ushort);
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static int addreseq(Fs*, Tcpctl*, Tcppriv*, Tcp*, Block**, ushort);
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static int dumpreseq(Tcpctl*);
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static void getreseq(Tcpctl*, Tcp*, Block**, ushort*);
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static void limbo(Conv*, uchar*, uchar*, Tcp*, int);
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@ -815,7 +818,7 @@ backoff(int n)
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}
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static void
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localclose(Conv *s, char *reason) /* called with tcb locked */
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localclose(Conv *s, char *reason) /* called with c locked */
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{
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Tcpctl *tcb;
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Tcppriv *tpriv;
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@ -1186,6 +1189,7 @@ ntohtcp6(Tcp *tcph, Block **bpp)
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hdrlen = (h->tcpflag[0]>>2) & ~3;
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if(hdrlen < TCP6_HDRSIZE) {
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freeblist(*bpp);
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*bpp = nil;
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return -1;
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}
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@ -1250,6 +1254,7 @@ ntohtcp4(Tcp *tcph, Block **bpp)
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hdrlen = (h->tcpflag[0]>>2) & ~3;
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if(hdrlen < TCP4_HDRSIZE) {
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freeblist(*bpp);
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*bpp = nil;
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return -1;
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}
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@ -1318,8 +1323,8 @@ tcpsndsyn(Conv *s, Tcpctl *tcb)
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tpriv->stats[Mss] = tcb->mss;
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}
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void
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sndrst(Proto *tcp, uchar *source, uchar *dest, ushort length, Tcp *seg, uchar version, char *reason)
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static int
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sndrst(Proto *tcp, uchar *source, uchar *dest, ushort length, Tcp *seg, uchar version, char *reason, Routehint *rh)
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{
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Block *hbp;
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uchar rflags;
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@ -1332,7 +1337,7 @@ sndrst(Proto *tcp, uchar *source, uchar *dest, ushort length, Tcp *seg, uchar ve
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tpriv = tcp->priv;
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if(seg->flags & RST)
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return;
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return -1;
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/* make pseudo header */
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switch(version) {
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@ -1386,19 +1391,12 @@ sndrst(Proto *tcp, uchar *source, uchar *dest, ushort length, Tcp *seg, uchar ve
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switch(version) {
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case V4:
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hbp = htontcp4(seg, nil, &ph4, nil);
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if(hbp == nil)
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return;
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ipoput4(tcp->f, hbp, 0, MAXTTL, DFLTTOS, nil);
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break;
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return ipoput4(tcp->f, hbp, 0, MAXTTL, DFLTTOS, rh);
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case V6:
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hbp = htontcp6(seg, nil, &ph6, nil);
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if(hbp == nil)
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return;
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ipoput6(tcp->f, hbp, 0, MAXTTL, DFLTTOS, nil);
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break;
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default:
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panic("sndrst2: version %d", version);
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return ipoput6(tcp->f, hbp, 0, MAXTTL, DFLTTOS, rh);
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}
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return -1;
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}
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/*
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@ -1454,12 +1452,19 @@ tcphangup(Conv *s)
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static int
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sndsynack(Proto *tcp, Limbo *lp)
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{
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Routehint rh;
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Route *rt;
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Block *hbp;
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Tcp4hdr ph4;
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Tcp6hdr ph6;
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Tcp seg;
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uint scale;
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rh.r = nil;
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rh.a = nil;
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if((rt = v6lookup(tcp->f, lp->raddr, lp->laddr, &rh)) == nil)
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return -1;
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/* make pseudo header */
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switch(lp->version) {
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case V4:
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@ -1483,7 +1488,7 @@ sndsynack(Proto *tcp, Limbo *lp)
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hnputs(ph6.tcpdport, lp->rport);
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break;
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default:
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panic("sndrst: version %d", lp->version);
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panic("sndsynack: version %d", lp->version);
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}
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memset(&seg, 0, sizeof seg);
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@ -1491,7 +1496,7 @@ sndsynack(Proto *tcp, Limbo *lp)
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seg.ack = lp->irs+1;
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seg.flags = SYN|ACK;
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seg.urg = 0;
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seg.mss = tcpmtu(v6lookup(tcp->f, lp->raddr, lp->laddr, nil), lp->version, &scale);
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seg.mss = tcpmtu(rt, lp->version, &scale);
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seg.wnd = QMAX;
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/* if the other side set scale, we should too */
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@ -1502,25 +1507,17 @@ sndsynack(Proto *tcp, Limbo *lp)
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seg.ws = 0;
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lp->sndscale = 0;
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}
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lp->lastsend = NOW;
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switch(lp->version) {
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case V4:
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hbp = htontcp4(&seg, nil, &ph4, nil);
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if(hbp == nil)
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return -1;
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ipoput4(tcp->f, hbp, 0, MAXTTL, DFLTTOS, nil);
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break;
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return ipoput4(tcp->f, hbp, 0, MAXTTL, DFLTTOS, &rh);
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case V6:
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hbp = htontcp6(&seg, nil, &ph6, nil);
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if(hbp == nil)
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return -1;
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ipoput6(tcp->f, hbp, 0, MAXTTL, DFLTTOS, nil);
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break;
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default:
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panic("sndsnack: version %d", lp->version);
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return ipoput6(tcp->f, hbp, 0, MAXTTL, DFLTTOS, &rh);
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}
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lp->lastsend = NOW;
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return 0;
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return -1;
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}
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#define hashipa(a, p) ( ( (a)[IPaddrlen-2] + (a)[IPaddrlen-1] + p )&LHTMASK )
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@ -1600,6 +1597,10 @@ limborexmit(Proto *tcp)
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if(!canqlock(tcp))
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return;
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if(waserror()){
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qunlock(tcp);
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return;
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}
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seen = 0;
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now = NOW;
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for(h = 0; h < NLHT && seen < tpriv->nlimbo; h++){
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@ -1622,8 +1623,8 @@ limborexmit(Proto *tcp)
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continue;
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if(sndsynack(tcp, lp) < 0){
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tpriv->nlimbo--;
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*l = lp->next;
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tpriv->nlimbo--;
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free(lp);
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continue;
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}
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@ -1632,6 +1633,7 @@ limborexmit(Proto *tcp)
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}
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}
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qunlock(tcp);
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poperror();
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}
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/*
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@ -2073,6 +2075,7 @@ tcpiput(Proto *tcp, Ipifc*, Block *bp)
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Conv *s;
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Fs *f;
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Tcppriv *tpriv;
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char *reason;
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uchar version;
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f = tcp->f;
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@ -2173,8 +2176,8 @@ tcpiput(Proto *tcp, Ipifc*, Block *bp)
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source, seg.source, dest, seg.dest);
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reset:
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qunlock(tcp);
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sndrst(tcp, source, dest, length, &seg, version, "no conversation");
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freeblist(bp);
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sndrst(tcp, source, dest, length, &seg, version, "no conversation", nil);
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return;
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}
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@ -2190,9 +2193,9 @@ reset:
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/* if this is a new SYN, put the call into limbo */
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if((seg.flags & SYN) && (seg.flags & ACK) == 0){
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freeblist(bp);
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limbo(s, source, dest, &seg, version);
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qunlock(tcp);
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freeblist(bp);
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return;
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}
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@ -2225,14 +2228,18 @@ reset:
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switch(tcb->state) {
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case Closed:
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sndrst(tcp, source, dest, length, &seg, version, "sending to Closed");
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closed:
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reason = "sending to Closed";
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reset2:
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freeblist(bp);
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bp = nil;
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sndrst(tcp, source, dest, length, &seg, version, reason, s);
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goto raise;
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case Syn_sent:
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if(seg.flags & ACK) {
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if(!seq_within(seg.ack, tcb->iss+1, tcb->snd.nxt)) {
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sndrst(tcp, source, dest, length, &seg, version,
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"bad seq in Syn_sent");
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goto raise;
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reason = "bad seq in Syn_sent";
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goto reset2;
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}
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}
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if(seg.flags & RST) {
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@ -2256,15 +2263,12 @@ reset:
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if(length != 0 || (seg.flags & FIN))
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break;
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freeblist(bp);
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goto output;
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}
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else
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freeblist(bp);
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qunlock(s);
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poperror();
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freeblist(bp);
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return;
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case Syn_received:
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/* doesn't matter if it's the correct ack, we're just trying to set timing */
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@ -2315,10 +2319,8 @@ reset:
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}
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/* Cannot accept so answer with a rst */
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if(length && tcb->state == Closed) {
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sndrst(tcp, source, dest, length, &seg, version, "sending to Closed");
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goto raise;
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}
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if(length && tcb->state == Closed)
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goto closed;
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/* The segment is beyond the current receive pointer so
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* queue the data in the resequence queue
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@ -2326,7 +2328,7 @@ reset:
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if(seg.seq != tcb->rcv.nxt)
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if(length != 0 || (seg.flags & (SYN|FIN))) {
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update(s, &seg);
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if(addreseq(f, tcb, tpriv, &seg, bp, length) < 0)
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if(addreseq(f, tcb, tpriv, &seg, &bp, length) < 0)
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print("reseq %I.%d -> %I.%d\n", s->raddr, s->rport, s->laddr, s->lport);
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tcb->flags |= FORCE; /* force duplicate ack; RFC 5681 §3.2 */
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goto output;
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@ -2344,7 +2346,8 @@ reset:
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if(tcb->state == Established) {
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tpriv->stats[EstabResets]++;
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if(tcb->rcv.nxt != seg.seq)
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print("out of order RST rcvd: %I.%d -> %I.%d, rcv.nxt %lux seq %lux\n", s->raddr, s->rport, s->laddr, s->lport, tcb->rcv.nxt, seg.seq);
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print("out of order RST rcvd: %I.%d -> %I.%d, rcv.nxt %lux seq %lux\n",
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s->raddr, s->rport, s->laddr, s->lport, tcb->rcv.nxt, seg.seq);
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}
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localclose(s, Econrefused);
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goto raise;
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@ -2356,9 +2359,8 @@ reset:
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switch(tcb->state) {
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case Syn_received:
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if(!seq_within(seg.ack, tcb->snd.una+1, tcb->snd.nxt)){
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sndrst(tcp, source, dest, length, &seg, version,
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"bad seq in Syn_received");
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goto raise;
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reason = "bad seq in Syn_received";
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goto reset2;
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}
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update(s, &seg);
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tcpsetstate(s, Established);
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@ -2416,15 +2418,15 @@ reset:
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tcb->rcv.urg = tcb->rcv.nxt;
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if(length == 0) {
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if(bp != nil)
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freeblist(bp);
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freeblist(bp);
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bp = nil;
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}
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else {
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switch(tcb->state){
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default:
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/* Ignore segment text */
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if(bp != nil)
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freeblist(bp);
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freeblist(bp);
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bp = nil;
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break;
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case Syn_received:
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@ -2433,7 +2435,7 @@ reset:
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/* If we still have some data place on
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* receive queue
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*/
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if(bp) {
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if(bp != nil) {
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qpassnolim(s->rq, packblock(bp));
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bp = nil;
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}
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@ -2448,14 +2450,8 @@ reset:
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break;
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case Finwait2:
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/* no process to read the data, send a reset */
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if(bp != nil)
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freeblist(bp);
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sndrst(tcp, source, dest, length, &seg, version,
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"send to Finwait2");
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qunlock(s);
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poperror();
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return;
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reason = "send to Finwait2";
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goto reset2;
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}
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}
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@ -2700,18 +2696,10 @@ tcpoutput(Conv *s)
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case V4:
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tcb->protohdr.tcp4hdr.vihl = IP_VER4;
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hbp = htontcp4(&seg, bp, &tcb->protohdr.tcp4hdr, tcb);
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if(hbp == nil) {
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freeblist(bp);
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return;
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}
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break;
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case V6:
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tcb->protohdr.tcp6hdr.vcf[0] = IP_VER6;
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hbp = htontcp6(&seg, bp, &tcb->protohdr.tcp6hdr, tcb);
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if(hbp == nil) {
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freeblist(bp);
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return;
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}
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break;
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default:
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hbp = nil; /* to suppress a warning */
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@ -2751,19 +2739,13 @@ tcpoutput(Conv *s)
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switch(version){
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case V4:
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if(ipoput4(f, hbp, 0, s->ttl, s->tos, s) < 0){
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/* a negative return means no route */
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localclose(s, "no route");
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}
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if(ipoput4(f, hbp, 0, s->ttl, s->tos, s) < 0)
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localclose(s, Enoroute);
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break;
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case V6:
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if(ipoput6(f, hbp, 0, s->ttl, s->tos, s) < 0){
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/* a negative return means no route */
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localclose(s, "no route");
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}
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if(ipoput6(f, hbp, 0, s->ttl, s->tos, s) < 0)
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localclose(s, Enoroute);
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break;
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default:
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panic("tcpoutput2: version %d", version);
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}
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if((msgs%4) == 3){
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qunlock(s);
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@ -2775,7 +2757,7 @@ tcpoutput(Conv *s)
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/*
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* the BSD convention (hack?) for keep alives. resend last uchar acked.
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*/
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static void
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static int
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tcpsendka(Conv *s)
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{
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Tcp seg;
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@ -2811,21 +2793,13 @@ tcpsendka(Conv *s)
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/* Build header, link data and compute cksum */
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tcb->protohdr.tcp4hdr.vihl = IP_VER4;
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hbp = htontcp4(&seg, dbp, &tcb->protohdr.tcp4hdr, tcb);
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if(hbp == nil) {
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freeblist(dbp);
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return;
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}
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ipoput4(s->p->f, hbp, 0, s->ttl, s->tos, s);
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return ipoput4(s->p->f, hbp, 0, s->ttl, s->tos, s);
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}
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else {
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/* Build header, link data and compute cksum */
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tcb->protohdr.tcp6hdr.vcf[0] = IP_VER6;
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hbp = htontcp6(&seg, dbp, &tcb->protohdr.tcp6hdr, tcb);
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if(hbp == nil) {
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freeblist(dbp);
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return;
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}
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ipoput6(s->p->f, hbp, 0, s->ttl, s->tos, s);
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return ipoput6(s->p->f, hbp, 0, s->ttl, s->tos, s);
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}
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}
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@ -2860,8 +2834,9 @@ tcpkeepalive(void *v)
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if(tcb->state != Closed){
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if(--(tcb->kacounter) <= 0) {
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localclose(s, Etimedout);
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} else if(tcpsendka(s) < 0) {
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localclose(s, Enoroute);
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} else {
|
||||
tcpsendka(s);
|
||||
tcpgo(s->p->priv, &tcb->katimer);
|
||||
}
|
||||
}
|
||||
|
|
@ -3078,20 +3053,22 @@ logreseq(Fs *f, Reseq *r, ulong n)
|
|||
}
|
||||
|
||||
static int
|
||||
addreseq(Fs *f, Tcpctl *tcb, Tcppriv *tpriv, Tcp *seg, Block *bp, ushort length)
|
||||
addreseq(Fs *f, Tcpctl *tcb, Tcppriv *tpriv, Tcp *seg, Block **bpp, ushort length)
|
||||
{
|
||||
Reseq *rp, **rr;
|
||||
int qmax;
|
||||
|
||||
rp = malloc(sizeof(Reseq));
|
||||
if(rp == nil){
|
||||
freeblist(bp); /* bp always consumed by addreseq */
|
||||
freeblist(*bpp); /* *bpp always consumed by addreseq */
|
||||
*bpp = nil;
|
||||
return 0;
|
||||
}
|
||||
|
||||
rp->seg = *seg;
|
||||
rp->bp = bp;
|
||||
rp->bp = *bpp;
|
||||
rp->length = length;
|
||||
*bpp = nil;
|
||||
|
||||
tcb->reseqlen += length;
|
||||
tcb->nreseq++;
|
||||
|
|
@ -3177,6 +3154,7 @@ tcptrim(Tcpctl *tcb, Tcp *seg, Block **bp, ushort *length)
|
|||
}
|
||||
if(!accept) {
|
||||
freeblist(*bp);
|
||||
*bp = nil;
|
||||
return -1;
|
||||
}
|
||||
dupcnt = tcb->rcv.nxt - seg->seq;
|
||||
|
|
|
|||
Loading…
Reference in a new issue