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rudp: fix start generation randomization and cleanup

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the start generation was allocated by calling rand(),
which gives a value between 0 and 2^15.

Instead, make a newgen() function that returns a new
generation id in the full 32-bit range, but also
avoids 0 and Hangupgen special values.

Cleanup and make all helper functions static.
This commit is contained in:
cinap_lenrek 2024-04-21 13:08:19 +00:00
parent e4509d40cc
commit 314faec394
1 changed files with 49 additions and 44 deletions
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93
sys/src/9/ip/rudp.c
View file

@ -162,9 +162,6 @@ struct Rudppriv
};
static ulong generation = 0;
static Rendez rend;
/*
* protocol specific part of Conv
*/
@ -180,17 +177,17 @@ struct Rudpcb
/*
* 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 relsendack(Conv*, Reliable*, int);
static int reliput(Conv*, Block*, uchar*, ushort);
static Reliable *relstate(Rudpcb*, uchar*, ushort, char*);
static void relput(Reliable*);
static void relforget(Conv *, uchar*, int, int);
static void relackproc(void *);
static void relackq(Reliable *, Block*);
static void relhangup(Conv *, Reliable*);
static void relrexmit(Conv *, Reliable*);
static void relput(Reliable*);
static void rudpkick(void *x);
static void
rudpstartackproc(Proto *rudp)
@ -325,7 +322,7 @@ doipoput(Conv *c, Fs *f, Block *bp, int ttl, int tos)
ipoput4(f, bp, nil, ttl, tos, nil);
}
int
static int
flow(void *v)
{
Reliable *r = v;
@ -333,7 +330,7 @@ flow(void *v)
return UNACKED(r) <= Maxunacked;
}
void
static void
rudpkick(void *x)
{
Conv *c = x;
@ -471,7 +468,7 @@ rudpkick(void *x)
poperror();
}
void
static void
rudpiput(Proto *rudp, Ipifc *ifc, Block *bp)
{
int len, olen;
@ -598,7 +595,7 @@ rudpiput(Proto *rudp, Ipifc *ifc, Block *bp)
static char *rudpunknown = "unknown rudp ctl request";
char*
static char*
rudpctl(Conv *c, char **f, int n)
{
Rudpcb *ucb;
@ -634,7 +631,7 @@ rudpctl(Conv *c, char **f, int n)
return rudpunknown;
}
void
static void
rudpadvise(Proto *rudp, Block *bp, Ipifc *, char *msg)
{
Udphdr *h;
@ -665,7 +662,7 @@ rudpadvise(Proto *rudp, Block *bp, Ipifc *, char *msg)
freeblist(bp);
}
int
static int
rudpstats(Proto *rudp, char *buf, int len)
{
Rudppriv *upriv;
@ -711,7 +708,7 @@ rudpinit(Fs *fs)
/*
* Enqueue a copy of an unacked block for possible retransmissions
*/
void
static void
relackq(Reliable *r, Block *bp)
{
Block *np;
@ -732,7 +729,7 @@ relackq(Reliable *r, Block *bp)
/*
* retransmit unacked blocks
*/
void
static void
relackproc(void *a)
{
Rudpcb *ucb;
@ -766,37 +763,44 @@ loop:
goto loop;
}
static ulong
newgen(void)
{
static Lock lk;
static ulong gen = 0;
ulong r;
lock(&lk);
while(gen == 0 || gen == Hangupgen)
gen = (nrand(1<<16)<<16)|nrand(1<<16);
r = gen++;
unlock(&lk);
return r;
}
/*
* get the state record for a conversation
*/
Reliable*
static 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)
if(ipcmp(addr, r->addr) == 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);
ipmove(r->addr, addr);
r->port = port;
r->unacked = 0;
if(generation == Hangupgen)
generation++;
r->sndgen = generation++;
r->sndgen = newgen();
r->sndseq = 0;
r->ackrcvd = 0;
r->rcvgen = 0;
@ -807,6 +811,9 @@ relstate(Rudpcb *ucb, uchar *addr, ushort port, char *from)
r->ref = 0;
incref(r); /* one reference for being in the list */
DPRINT("from %s new state %lud for %I!%ud\n",
from, r->sndgen, r->addr, r->port);
*l = r;
}
@ -814,7 +821,7 @@ relstate(Rudpcb *ucb, uchar *addr, ushort port, char *from)
return r;
}
void
static void
relput(Reliable *r)
{
if(decref(r) == 0)
@ -824,7 +831,7 @@ relput(Reliable *r)
/*
* forget a Reliable state
*/
void
static void
relforget(Conv *c, uchar *ip, int port, int originator)
{
Rudpcb *ucb;
@ -852,7 +859,7 @@ relforget(Conv *c, uchar *ip, int port, int originator)
*
* called with ucb locked.
*/
int
static int
reliput(Conv *c, Block *bp, uchar *addr, ushort port)
{
Block *nbp;
@ -953,7 +960,7 @@ out:
return rv;
}
void
static void
relsendack(Conv *c, Reliable *r, int hangup)
{
Udphdr *uh;
@ -1007,7 +1014,7 @@ relsendack(Conv *c, Reliable *r, int hangup)
/*
* called with ucb locked (and c locked if user initiated close)
*/
void
static void
relhangup(Conv *c, Reliable *r)
{
int n;
@ -1029,9 +1036,7 @@ relhangup(Conv *c, Reliable *r)
r->rcvgen = 0;
r->rcvseq = 0;
r->acksent = 0;
if(generation == Hangupgen)
generation++;
r->sndgen = generation++;
r->sndgen = newgen();
r->sndseq = 0;
r->ackrcvd = 0;
r->xmits = 0;
@ -1042,7 +1047,7 @@ relhangup(Conv *c, Reliable *r)
/*
* called with ucb locked
*/
void
static void
relrexmit(Conv *c, Reliable *r)
{
Rudppriv *upriv;