/* *  This protocol is compatible with UDP's packet format. *  It could be done over UDP if need be. */#include	"u.h"#include	"../port/lib.h"#include	"mem.h"#include	"dat.h"#include	"fns.h"#include	"../port/error.h" #include	"ip.h" #define DEBUG	0#define DPRINT if(DEBUG)print #define SEQDIFF(a,b) ( (a)>=(b)?\			(a)-(b):\			0xffffffffUL-((b)-(a)) )#define INSEQ(a,start,end) ( (start)<=(end)?\				((a)>(start)&&(a)<=(end)):\				((a)>(start)||(a)<=(end)) )#define UNACKED(r) SEQDIFF(r->sndseq, r->ackrcvd)#define NEXTSEQ(a) ( (a)+1 == 0 ? 1 : (a)+1 ) enum{	UDP_HDRSIZE	= 20,	/* pseudo header + udp header */	UDP_PHDRSIZE	= 12,	/* pseudo header */	UDP_RHDRSIZE	= 36,	/* pseudo header + udp header + rudp header */	UDP_IPHDR	= 8,	/* ip header */	IP_UDPPROTO	= 254,	UDP_USEAD7	= 52,	UDP_USEAD6	= 36,	UDP_USEAD4	= 12, 	Rudprxms	= 200,	Rudptickms	= 50,	Rudpmaxxmit	= 10,	Maxunacked	= 100, }; #define Hangupgen	0xffffffff	/* used only in hangup messages */ typedef struct Udphdr Udphdr;struct Udphdr{	/* ip header */	uchar	vihl;		/* Version and header length */	uchar	tos;		/* Type of service */	uchar	length[2];	/* packet length */	uchar	id[2];		/* Identification */	uchar	frag[2];	/* Fragment information */ 	/* pseudo header starts here */	uchar	Unused;	uchar	udpproto;	/* Protocol */	uchar	udpplen[2];	/* Header plus data length */	uchar	udpsrc[4];	/* Ip source */	uchar	udpdst[4];	/* Ip destination */ 	/* udp header */	uchar	udpsport[2];	/* Source port */	uchar	udpdport[2];	/* Destination port */	uchar	udplen[2];	/* data length */	uchar	udpcksum[2];	/* Checksum */}; typedef struct Rudphdr Rudphdr;struct Rudphdr{	/* ip header */	uchar	vihl;		/* Version and header length */	uchar	tos;		/* Type of service */	uchar	length[2];	/* packet length */	uchar	id[2];		/* Identification */	uchar	frag[2];	/* Fragment information */ 	/* pseudo header starts here */	uchar	Unused;	uchar	udpproto;	/* Protocol */	uchar	udpplen[2];	/* Header plus data length */	uchar	udpsrc[4];	/* Ip source */	uchar	udpdst[4];	/* Ip destination */ 	/* udp header */	uchar	udpsport[2];	/* Source port */	uchar	udpdport[2];	/* Destination port */	uchar	udplen[2];	/* data length (includes rudp header) */	uchar	udpcksum[2];	/* Checksum */ 	/* rudp header */	uchar	relseq[4];	/* id of this packet (or 0) */	uchar	relsgen[4];	/* generation/time stamp */	uchar	relack[4];	/* packet being acked (or 0) */	uchar	relagen[4];	/* generation/time stamp */};  /* *  one state structure per destination */typedef struct Reliable Reliable;struct Reliable{	Ref; 	Reliable *next; 	uchar	addr[IPaddrlen];	/* always V6 when put here */	ushort	port; 	Block	*unacked;	/* unacked msg list */	Block	*unackedtail;	/*  and its tail */ 	int	timeout;	/* time since first unacked msg sent */	int	xmits;		/* number of times first unacked msg sent */ 	ulong	sndseq;		/* next packet to be sent */	ulong	sndgen;		/*  and its generation */ 	ulong	rcvseq;		/* last packet received */	ulong	rcvgen;		/*  and its generation */ 	ulong	acksent;	/* last ack sent */	ulong	ackrcvd;	/* last msg for which ack was rcvd */ 	/* flow control */	QLock	lock;	Rendez	vous;	int	blocked;};   /* MIB II counters */typedef struct Rudpstats Rudpstats;struct Rudpstats{	ulong	rudpInDatagrams;	ulong	rudpNoPorts;	ulong	rudpInErrors;	ulong	rudpOutDatagrams;}; typedef struct Rudppriv Rudppriv;struct Rudppriv{	Ipht	ht; 	/* MIB counters */	Rudpstats	ustats; 	/* non-MIB stats */	ulong	csumerr;		/* checksum errors */	ulong	lenerr;			/* short packet */	ulong	rxmits;			/* # of retransmissions */	ulong	orders;			/* # of out of order pkts */ 	/* keeping track of the ack kproc */	int	ackprocstarted;	QLock	apl;};  static ulong generation = 0;static Rendez rend; /* *  protocol specific part of Conv */typedef struct Rudpcb Rudpcb;struct Rudpcb{	QLock;	uchar	headers;	uchar	randdrop;	Reliable *r;}; /* * local functions  */void	relsendack(Conv*, Reliable*, int);int	reliput(Conv*, Block*, uchar*, ushort);Reliable *relstate(Rudpcb*, uchar*, ushort, char*);void	relput(Reliable*);void	relforget(Conv *, uchar*, int, int);void	relackproc(void *);void	relackq(Reliable *, Block*);void	relhangup(Conv *, Reliable*);void	relrexmit(Conv *, Reliable*);void	relput(Reliable*);void	rudpkick(void *x); static voidrudpstartackproc(Proto *rudp){	Rudppriv *rpriv;	char kpname[KNAMELEN]; 	rpriv = rudp->priv;	if(rpriv->ackprocstarted == 0){		qlock(&rpriv->apl);		if(rpriv->ackprocstarted == 0){			sprint(kpname, "#I%drudpack", rudp->f->dev);			kproc(kpname, relackproc, rudp, 0);			rpriv->ackprocstarted = 1;		}		qunlock(&rpriv->apl);	}} static char*rudpconnect(Conv *c, char **argv, int argc){	char *e;	Rudppriv *upriv; 	upriv = c->p->priv;	rudpstartackproc(c->p);	e = Fsstdconnect(c, argv, argc);	Fsconnected(c, e);	iphtadd(&upriv->ht, c); 	return e;}  static intrudpstate(Conv *c, char *state, int n){	Rudpcb *ucb;	Reliable *r;	int m; 	m = snprint(state, n, "%s", c->inuse?"Open":"Closed");	ucb = (Rudpcb*)c->ptcl;	qlock(ucb);	for(r = ucb->r; r; r = r->next)		m += snprint(state+m, n-m, " %I/%ld", r->addr, UNACKED(r));	qunlock(ucb);	return m;} static char*rudpannounce(Conv *c, char** argv, int argc){	char *e;	Rudppriv *upriv; 	upriv = c->p->priv;	rudpstartackproc(c->p);	e = Fsstdannounce(c, argv, argc);	if(e != nil)		return e;	Fsconnected(c, nil);	iphtadd(&upriv->ht, c); 	return nil;} static voidrudpcreate(Conv *c){	c->rq = qopen(64*1024, Qmsg, 0, 0);	c->wq = qopen(64*1024, Qkick, rudpkick, c);} static voidrudpclose(Conv *c){	Rudpcb *ucb;	Reliable *r, *nr;	Rudppriv *upriv; 	upriv = c->p->priv;	iphtrem(&upriv->ht, c); 	/* force out any delayed acks */	ucb = (Rudpcb*)c->ptcl;	qlock(ucb);	for(r = ucb->r; r; r = r->next){		if(r->acksent != r->rcvseq)			relsendack(c, r, 0);	}	qunlock(ucb); 	qclose(c->rq);	qclose(c->wq);	qclose(c->eq);	ipmove(c->laddr, IPnoaddr);	ipmove(c->raddr, IPnoaddr);	c->lport = 0;	c->rport = 0; 	ucb->headers = 0;	ucb->randdrop = 0;	qlock(ucb);	for(r = ucb->r; r; r = nr){		if(r->acksent != r->rcvseq)			relsendack(c, r, 0);		nr = r->next;		relhangup(c, r);		relput(r);	}	ucb->r = 0; 	qunlock(ucb);} /* *  randomly don't send packets */static voiddoipoput(Conv *c, Fs *f, Block *bp, int x, int ttl, int tos){	Rudpcb *ucb; 	ucb = (Rudpcb*)c->ptcl;	if(ucb->randdrop && nrand(100) < ucb->randdrop)		freeblist(bp);	else		ipoput4(f, bp, x, ttl, tos, nil);} intflow(void *v){	Reliable *r = v; 	return UNACKED(r) <= Maxunacked;} voidrudpkick(void *x){	Conv *c = x;	Udphdr *uh;	ushort rport;	uchar laddr[IPaddrlen], raddr[IPaddrlen];	Block *bp;	Rudpcb *ucb;	Rudphdr *rh;	Reliable *r;	int dlen, ptcllen;	Rudppriv *upriv;	Fs *f; 	upriv = c->p->priv;	f = c->p->f; 	netlog(c->p->f, Logrudp, "rudp: kick\n");	bp = qget(c->wq);	if(bp == nil)		return; 	ucb = (Rudpcb*)c->ptcl;	switch(ucb->headers) {	case 7:		/* get user specified addresses */		bp = pullupblock(bp, UDP_USEAD7);		if(bp == nil)			return;		ipmove(raddr, bp->rp);		bp->rp += IPaddrlen;		ipmove(laddr, bp->rp);		bp->rp += IPaddrlen;		/* pick interface closest to dest */		if(ipforme(f, laddr) != Runi)			findlocalip(f, laddr, raddr);		bp->rp += IPaddrlen;		/* Ignore ifc address */		rport = nhgets(bp->rp);		bp->rp += 2+2;			/* Ignore local port */		break;	case 6:		/* get user specified addresses */		bp = pullupblock(bp, UDP_USEAD6);		if(bp == nil)			return;		ipmove(raddr, bp->rp);		bp->rp += IPaddrlen;		ipmove(laddr, bp->rp);		bp->rp += IPaddrlen;		/* pick interface closest to dest */		if(ipforme(f, laddr) != Runi)			findlocalip(f, laddr, raddr);		rport = nhgets(bp->rp); 		bp->rp += 4;			/* Igonore local port */		break;	default:		ipmove(raddr, c->raddr);		ipmove(laddr, c->laddr);		rport = c->rport; 		break;	} 	dlen = blocklen(bp); 	/* Make space to fit rudp & ip header */	bp = padblock(bp, UDP_IPHDR+UDP_RHDRSIZE);	if(bp == nil)		return; 	uh = (Udphdr *)(bp->rp);	uh->vihl = IP_VER4; 	rh = (Rudphdr*)uh; 	ptcllen = dlen + (UDP_RHDRSIZE-UDP_PHDRSIZE);	uh->Unused = 0;	uh->udpproto = IP_UDPPROTO;	uh->frag[0] = 0;	uh->frag[1] = 0;	hnputs(uh->udpplen, ptcllen);	switch(ucb->headers){	case 6:	case 7:		v6tov4(uh->udpdst, raddr);		hnputs(uh->udpdport, rport);		v6tov4(uh->udpsrc, laddr);		break;	default:		v6tov4(uh->udpdst, c->raddr);		hnputs(uh->udpdport, c->rport);		if(ipcmp(c->laddr, IPnoaddr) == 0)			findlocalip(f, c->laddr, c->raddr);		v6tov4(uh->udpsrc, c->laddr);		break;	}	hnputs(uh->udpsport, c->lport);	hnputs(uh->udplen, ptcllen);	uh->udpcksum[0] = 0;	uh->udpcksum[1] = 0; 	qlock(ucb);	r = relstate(ucb, raddr, rport, "kick");	r->sndseq = NEXTSEQ(r->sndseq);	hnputl(rh->relseq, r->sndseq);	hnputl(rh->relsgen, r->sndgen); 	hnputl(rh->relack, r->rcvseq);  /* ACK last rcvd packet */	hnputl(rh->relagen, r->rcvgen); 	if(r->rcvseq != r->acksent)		r->acksent = r->rcvseq; 	hnputs(uh->udpcksum, ptclcsum(bp, UDP_IPHDR, dlen+UDP_RHDRSIZE)); 	relackq(r, bp);	qunlock(ucb); 	upriv->ustats.rudpOutDatagrams++; 	DPRINT("sent: %lud/%lud, %lud/%lud\n", 		r->sndseq, r->sndgen, r->rcvseq, r->rcvgen); 	doipoput(c, f, bp, 0, c->ttl, c->tos); 	if(waserror()) {		relput(r);		qunlock(&r->lock);		nexterror();	} 	/* flow control of sorts */	qlock(&r->lock);	if(UNACKED(r) > Maxunacked){		r->blocked = 1;		sleep(&r->vous, flow, r);		r->blocked = 0;	} 	qunlock(&r->lock);	relput(r);	poperror();} voidrudpiput(Proto *rudp, Ipifc *ifc, Block *bp){	int len, olen, ottl;	Udphdr *uh;	Conv *c;	Rudpcb *ucb;	uchar raddr[IPaddrlen], laddr[IPaddrlen];	ushort rport, lport;	Rudppriv *upriv;	Fs *f;	uchar *p; 	upriv = rudp->priv;	f = rudp->f; 	upriv->ustats.rudpInDatagrams++; 	uh = (Udphdr*)(bp->rp);

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