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- /*
- * Reliable User Datagram Protocol, currently only for IPv4.
- * 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 void
- rudpstartackproc(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);
- 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 int
- rudpstate(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));
- m += snprint(state+m, n-m, "\n");
- 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 void
- rudpcreate(Conv *c)
- {
- c->rq = qopen(64*1024, Qmsg, 0, 0);
- c->wq = qopen(64*1024, Qkick, rudpkick, c);
- }
- static void
- rudpclose(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 void
- doipoput(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);
- }
- int
- flow(void *v)
- {
- Reliable *r = v;
- return UNACKED(r) <= Maxunacked;
- }
- void
- rudpkick(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: /* OBS */
- /* 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: /* OBS */
- 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();
- }
- void
- rudpiput(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);
- /* Put back pseudo header for checksum
- * (remember old values for icmpnoconv())
- */
- ottl = uh->Unused;
- uh->Unused = 0;
- len = nhgets(uh->udplen);
- olen = nhgets(uh->udpplen);
- hnputs(uh->udpplen, len);
- v4tov6(raddr, uh->udpsrc);
- v4tov6(laddr, uh->udpdst);
- lport = nhgets(uh->udpdport);
- rport = nhgets(uh->udpsport);
- if(nhgets(uh->udpcksum)) {
- if(ptclcsum(bp, UDP_IPHDR, len+UDP_PHDRSIZE)) {
- upriv->ustats.rudpInErrors++;
- upriv->csumerr++;
- netlog(f, Logrudp, "rudp: checksum error %I\n", raddr);
- DPRINT("rudp: checksum error %I\n", raddr);
- freeblist(bp);
- return;
- }
- }
- qlock(rudp);
- c = iphtlook(&upriv->ht, raddr, rport, laddr, lport);
- if(c == nil){
- /* no conversation found */
- upriv->ustats.rudpNoPorts++;
- qunlock(rudp);
- netlog(f, Logudp, "udp: no conv %I!%d -> %I!%d\n", raddr, rport,
- laddr, lport);
- uh->Unused = ottl;
- hnputs(uh->udpplen, olen);
- icmpnoconv(f, bp);
- freeblist(bp);
- return;
- }
- ucb = (Rudpcb*)c->ptcl;
- qlock(ucb);
- qunlock(rudp);
- if(reliput(c, bp, raddr, rport) < 0){
- qunlock(ucb);
- freeb(bp);
- return;
- }
- /*
- * Trim the packet down to data size
- */
- len -= (UDP_RHDRSIZE-UDP_PHDRSIZE);
- bp = trimblock(bp, UDP_IPHDR+UDP_RHDRSIZE, len);
- if(bp == nil) {
- netlog(f, Logrudp, "rudp: len err %I.%d -> %I.%d\n",
- raddr, rport, laddr, lport);
- DPRINT("rudp: len err %I.%d -> %I.%d\n",
- raddr, rport, laddr, lport);
- upriv->lenerr++;
- return;
- }
- netlog(f, Logrudpmsg, "rudp: %I.%d -> %I.%d l %d\n",
- raddr, rport, laddr, lport, len);
- switch(ucb->headers){
- case 7:
- /* pass the src address */
- bp = padblock(bp, UDP_USEAD7);
- p = bp->rp;
- ipmove(p, raddr); p += IPaddrlen;
- ipmove(p, laddr); p += IPaddrlen;
- ipmove(p, ifc->lifc->local); p += IPaddrlen;
- hnputs(p, rport); p += 2;
- hnputs(p, lport);
- break;
- case 6: /* OBS */
- /* pass the src address */
- bp = padblock(bp, UDP_USEAD6);
- p = bp->rp;
- ipmove(p, raddr); p += IPaddrlen;
- ipmove(p, ipforme(f, laddr)==Runi ? laddr : ifc->lifc->local); p += IPaddrlen;
- hnputs(p, rport); p += 2;
- hnputs(p, lport);
- break;
- default:
- /* connection oriented rudp */
- if(ipcmp(c->raddr, IPnoaddr) == 0){
- /* save the src address in the conversation */
- ipmove(c->raddr, raddr);
- c->rport = rport;
- /* reply with the same ip address (if not broadcast) */
- if(ipforme(f, laddr) == Runi)
- ipmove(c->laddr, laddr);
- else
- v4tov6(c->laddr, ifc->lifc->local);
- }
- break;
- }
- if(bp->next)
- bp = concatblock(bp);
- if(qfull(c->rq)) {
- netlog(f, Logrudp, "rudp: qfull %I.%d -> %I.%d\n", raddr, rport,
- laddr, lport);
- freeblist(bp);
- }
- else
- qpass(c->rq, bp);
-
- qunlock(ucb);
- }
- static char *rudpunknown = "unknown rudp ctl request";
- char*
- rudpctl(Conv *c, char **f, int n)
- {
- Rudpcb *ucb;
- uchar ip[IPaddrlen];
- int x;
- ucb = (Rudpcb*)c->ptcl;
- if(n < 1)
- return rudpunknown;
- if(strcmp(f[0], "headers++4") == 0){
- ucb->headers = 7; /* new headers format */
- return nil;
- } else if(strcmp(f[0], "headers") == 0){ /* OBS */
- ucb->headers = 6;
- return nil;
- } else if(strcmp(f[0], "hangup") == 0){
- if(n < 3)
- return "bad syntax";
- parseip(ip, f[1]);
- x = atoi(f[2]);
- qlock(ucb);
- relforget(c, ip, x, 1);
- qunlock(ucb);
- return nil;
- } else if(strcmp(f[0], "randdrop") == 0){
- x = 10; /* default is 10% */
- if(n > 1)
- x = atoi(f[1]);
- if(x > 100 || x < 0)
- return "illegal rudp drop rate";
- ucb->randdrop = x;
- return nil;
- }
- return rudpunknown;
- }
- void
- rudpadvise(Proto *rudp, Block *bp, char *msg)
- {
- Udphdr *h;
- uchar source[IPaddrlen], dest[IPaddrlen];
- ushort psource, pdest;
- Conv *s, **p;
- h = (Udphdr*)(bp->rp);
- v4tov6(dest, h->udpdst);
- v4tov6(source, h->udpsrc);
- psource = nhgets(h->udpsport);
- pdest = nhgets(h->udpdport);
- /* Look for a connection */
- for(p = rudp->conv; *p; p++) {
- s = *p;
- if(s->rport == pdest)
- if(s->lport == psource)
- if(ipcmp(s->raddr, dest) == 0)
- if(ipcmp(s->laddr, source) == 0){
- qhangup(s->rq, msg);
- qhangup(s->wq, msg);
- break;
- }
- }
- freeblist(bp);
- }
- int
- rudpstats(Proto *rudp, char *buf, int len)
- {
- Rudppriv *upriv;
- upriv = rudp->priv;
- return snprint(buf, len, "%lud %lud %lud %lud %lud %lud\n",
- upriv->ustats.rudpInDatagrams,
- upriv->ustats.rudpNoPorts,
- upriv->ustats.rudpInErrors,
- upriv->ustats.rudpOutDatagrams,
- upriv->rxmits,
- upriv->orders);
- }
- void
- rudpinit(Fs *fs)
- {
- Proto *rudp;
- rudp = smalloc(sizeof(Proto));
- rudp->priv = smalloc(sizeof(Rudppriv));
- rudp->name = "rudp";
- rudp->connect = rudpconnect;
- rudp->announce = rudpannounce;
- rudp->ctl = rudpctl;
- rudp->state = rudpstate;
- rudp->create = rudpcreate;
- rudp->close = rudpclose;
- rudp->rcv = rudpiput;
- rudp->advise = rudpadvise;
- rudp->stats = rudpstats;
- rudp->ipproto = IP_UDPPROTO;
- rudp->nc = 16;
- rudp->ptclsize = sizeof(Rudpcb);
- Fsproto(fs, rudp);
- }
- /*********************************************/
- /* Here starts the reliable helper functions */
- /*********************************************/
- /*
- * Enqueue a copy of an unacked block for possible retransmissions
- */
- void
- relackq(Reliable *r, Block *bp)
- {
- Block *np;
- np = copyblock(bp, blocklen(bp));
- if(r->unacked)
- r->unackedtail->list = np;
- else {
- /* restart timer */
- r->timeout = 0;
- r->xmits = 1;
- r->unacked = np;
- }
- r->unackedtail = np;
- np->list = nil;
- }
- /*
- * retransmit unacked blocks
- */
- void
- relackproc(void *a)
- {
- Rudpcb *ucb;
- Proto *rudp;
- Reliable *r;
- Conv **s, *c;
- rudp = (Proto *)a;
- loop:
- tsleep(&up->sleep, return0, 0, Rudptickms);
- for(s = rudp->conv; *s; s++) {
- c = *s;
- ucb = (Rudpcb*)c->ptcl;
- qlock(ucb);
- for(r = ucb->r; r; r = r->next) {
- if(r->unacked != nil){
- r->timeout += Rudptickms;
- if(r->timeout > Rudprxms*r->xmits)
- relrexmit(c, r);
- }
- if(r->acksent != r->rcvseq)
- relsendack(c, r, 0);
- }
- qunlock(ucb);
- }
- goto loop;
- }
- /*
- * get the state record for a conversation
- */
- Reliable*
- relstate(Rudpcb *ucb, uchar *addr, ushort port, char *from)
- {
- Reliable *r, **l;
- l = &ucb->r;
- for(r = *l; r; r = *l){
- if(memcmp(addr, r->addr, IPaddrlen) == 0 &&
- port == r->port)
- break;
- l = &r->next;
- }
- /* no state for this addr/port, create some */
- if(r == nil){
- while(generation == 0)
- generation = rand();
- DPRINT("from %s new state %lud for %I!%ud\n",
- from, generation, addr, port);
- r = smalloc(sizeof(Reliable));
- memmove(r->addr, addr, IPaddrlen);
- r->port = port;
- r->unacked = 0;
- if(generation == Hangupgen)
- generation++;
- r->sndgen = generation++;
- r->sndseq = 0;
- r->ackrcvd = 0;
- r->rcvgen = 0;
- r->rcvseq = 0;
- r->acksent = 0;
- r->xmits = 0;
- r->timeout = 0;
- r->ref = 0;
- incref(r); /* one reference for being in the list */
- *l = r;
- }
- incref(r);
- return r;
- }
- void
- relput(Reliable *r)
- {
- if(decref(r) == 0)
- free(r);
- }
- /*
- * forget a Reliable state
- */
- void
- relforget(Conv *c, uchar *ip, int port, int originator)
- {
- Rudpcb *ucb;
- Reliable *r, **l;
- ucb = (Rudpcb*)c->ptcl;
- l = &ucb->r;
- for(r = *l; r; r = *l){
- if(ipcmp(ip, r->addr) == 0 && port == r->port){
- *l = r->next;
- if(originator)
- relsendack(c, r, 1);
- relhangup(c, r);
- relput(r); /* remove from the list */
- break;
- }
- l = &r->next;
- }
- }
- /*
- * process a rcvd reliable packet. return -1 if not to be passed to user process,
- * 0 therwise.
- *
- * called with ucb locked.
- */
- int
- reliput(Conv *c, Block *bp, uchar *addr, ushort port)
- {
- Block *nbp;
- Rudpcb *ucb;
- Rudppriv *upriv;
- Udphdr *uh;
- Reliable *r;
- Rudphdr *rh;
- ulong seq, ack, sgen, agen, ackreal;
- int rv = -1;
- /* get fields */
- uh = (Udphdr*)(bp->rp);
- rh = (Rudphdr*)uh;
- seq = nhgetl(rh->relseq);
- sgen = nhgetl(rh->relsgen);
- ack = nhgetl(rh->relack);
- agen = nhgetl(rh->relagen);
- upriv = c->p->priv;
- ucb = (Rudpcb*)c->ptcl;
- r = relstate(ucb, addr, port, "input");
- DPRINT("rcvd %lud/%lud, %lud/%lud, r->sndgen = %lud\n",
- seq, sgen, ack, agen, r->sndgen);
- /* if acking an incorrect generation, ignore */
- if(ack && agen != r->sndgen)
- goto out;
- /* Look for a hangup */
- if(sgen == Hangupgen) {
- if(agen == r->sndgen)
- relforget(c, addr, port, 0);
- goto out;
- }
- /* make sure we're not talking to a new remote side */
- if(r->rcvgen != sgen){
- if(seq != 0 && seq != 1)
- goto out;
- /* new connection */
- if(r->rcvgen != 0){
- DPRINT("new con r->rcvgen = %lud, sgen = %lud\n", r->rcvgen, sgen);
- relhangup(c, r);
- }
- r->rcvgen = sgen;
- }
- /* dequeue acked packets */
- if(ack && agen == r->sndgen){
- ackreal = 0;
- while(r->unacked != nil && INSEQ(ack, r->ackrcvd, r->sndseq)){
- nbp = r->unacked;
- r->unacked = nbp->list;
- DPRINT("%lud/%lud acked, r->sndgen = %lud\n",
- ack, agen, r->sndgen);
- freeb(nbp);
- r->ackrcvd = NEXTSEQ(r->ackrcvd);
- ackreal = 1;
- }
- /* flow control */
- if(UNACKED(r) < Maxunacked/8 && r->blocked)
- wakeup(&r->vous);
- /*
- * retransmit next packet if the acked packet
- * was transmitted more than once
- */
- if(ackreal && r->unacked != nil){
- r->timeout = 0;
- if(r->xmits > 1){
- r->xmits = 1;
- relrexmit(c, r);
- }
- }
-
- }
- /* no message or input queue full */
- if(seq == 0 || qfull(c->rq))
- goto out;
- /* refuse out of order delivery */
- if(seq != NEXTSEQ(r->rcvseq)){
- relsendack(c, r, 0); /* tell him we got it already */
- upriv->orders++;
- DPRINT("out of sequence %lud not %lud\n", seq, NEXTSEQ(r->rcvseq));
- goto out;
- }
- r->rcvseq = seq;
- rv = 0;
- out:
- relput(r);
- return rv;
- }
- void
- relsendack(Conv *c, Reliable *r, int hangup)
- {
- Udphdr *uh;
- Block *bp;
- Rudphdr *rh;
- int ptcllen;
- Fs *f;
- bp = allocb(UDP_IPHDR + UDP_RHDRSIZE);
- if(bp == nil)
- return;
- bp->wp += UDP_IPHDR + UDP_RHDRSIZE;
- f = c->p->f;
- uh = (Udphdr *)(bp->rp);
- uh->vihl = IP_VER4;
- rh = (Rudphdr*)uh;
- ptcllen = (UDP_RHDRSIZE-UDP_PHDRSIZE);
- uh->Unused = 0;
- uh->udpproto = IP_UDPPROTO;
- uh->frag[0] = 0;
- uh->frag[1] = 0;
- hnputs(uh->udpplen, ptcllen);
- v6tov4(uh->udpdst, r->addr);
- hnputs(uh->udpdport, r->port);
- hnputs(uh->udpsport, c->lport);
- if(ipcmp(c->laddr, IPnoaddr) == 0)
- findlocalip(f, c->laddr, c->raddr);
- v6tov4(uh->udpsrc, c->laddr);
- hnputs(uh->udplen, ptcllen);
- if(hangup)
- hnputl(rh->relsgen, Hangupgen);
- else
- hnputl(rh->relsgen, r->sndgen);
- hnputl(rh->relseq, 0);
- hnputl(rh->relagen, r->rcvgen);
- hnputl(rh->relack, r->rcvseq);
- if(r->acksent < r->rcvseq)
- r->acksent = r->rcvseq;
- uh->udpcksum[0] = 0;
- uh->udpcksum[1] = 0;
- hnputs(uh->udpcksum, ptclcsum(bp, UDP_IPHDR, UDP_RHDRSIZE));
- DPRINT("sendack: %lud/%lud, %lud/%lud\n", 0L, r->sndgen, r->rcvseq, r->rcvgen);
- doipoput(c, f, bp, 0, c->ttl, c->tos);
- }
- /*
- * called with ucb locked (and c locked if user initiated close)
- */
- void
- relhangup(Conv *c, Reliable *r)
- {
- int n;
- Block *bp;
- char hup[ERRMAX];
- n = snprint(hup, sizeof(hup), "hangup %I!%d", r->addr, r->port);
- qproduce(c->eq, hup, n);
- /*
- * dump any unacked outgoing messages
- */
- for(bp = r->unacked; bp != nil; bp = r->unacked){
- r->unacked = bp->list;
- bp->list = nil;
- freeb(bp);
- }
- r->rcvgen = 0;
- r->rcvseq = 0;
- r->acksent = 0;
- if(generation == Hangupgen)
- generation++;
- r->sndgen = generation++;
- r->sndseq = 0;
- r->ackrcvd = 0;
- r->xmits = 0;
- r->timeout = 0;
- wakeup(&r->vous);
- }
- /*
- * called with ucb locked
- */
- void
- relrexmit(Conv *c, Reliable *r)
- {
- Rudppriv *upriv;
- Block *np;
- Fs *f;
- upriv = c->p->priv;
- f = c->p->f;
- r->timeout = 0;
- if(r->xmits++ > Rudpmaxxmit){
- relhangup(c, r);
- return;
- }
- upriv->rxmits++;
- np = copyblock(r->unacked, blocklen(r->unacked));
- DPRINT("rxmit r->ackrvcd+1 = %lud\n", r->ackrcvd+1);
- doipoput(c, f, np, 0, c->ttl, c->tos);
- }
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