ref: c07ad86666257eb54db8723b330d289b13036d44
dir: /os/ip/rudp.c/
/*
* 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, 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 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));
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:
/* 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();
}
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 converstation 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:
/* 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;
return nil;
} else if(strcmp(f[0], "headers") == 0){
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);
}