PERFORCE change 81737 for review
Robert Watson
rwatson at FreeBSD.org
Tue Aug 9 16:14:10 GMT 2005
http://perforce.freebsd.org/chv.cgi?CH=81737
Change 81737 by rwatson at rwatson_peppercorn on 2005/08/09 16:13:47
Add helper function ip_findmoptions(), which accepts an inpcb, and
attempts to atomically return either an existing set of IP
multicast options for the PCB, or a newlly allocated set with
default values. The inpcb is returned locked. This function may
sleep.
Call ip_moptions() to acquire a reference to a PCB's socket
options, and perform the update of the options while holding the
PCB lock. Release the lock before returning.
Remove garbage collection of multicast options when values return
to the default, as this complicates locking substantially. Most
applications allocate a socket either to be multicast, or not, and
don't tend to keep around sockets that have previously been used
for multicast, then used for unicast.
Affected files ...
.. //depot/projects/netsmp/src/sys/netinet/ip_output.c#5 edit
Differences ...
==== //depot/projects/netsmp/src/sys/netinet/ip_output.c#5 (text+ko) ====
@@ -99,6 +99,7 @@
static int ip_getmoptions(struct inpcb *, struct sockopt *);
static int ip_pcbopts(struct inpcb *, int, struct mbuf *);
static int ip_setmoptions(struct inpcb *, struct sockopt *);
+static struct ip_moptions *ip_findmoptions(struct inpcb *inp);
int ip_optcopy(struct ip *, struct ip *);
@@ -1569,6 +1570,39 @@
}
/*
+ * Given an inpcb, return its multicast options structure pointer. Accepts
+ * an unlocked inpcb pointer, but will return it locked. May sleep.
+ */
+static struct ip_moptions *
+ip_findmoptions(struct inpcb *inp)
+{
+ struct ip_moptions *imo;
+
+ INP_LOCK(inp);
+ if (inp->inp_moptions != NULL)
+ return (inp->inp_moptions);
+
+ INP_UNLOCK(inp);
+
+ imo = (struct ip_moptions*)malloc(sizeof(*imo), M_IPMOPTS, M_WAITOK);
+
+ imo->imo_multicast_ifp = NULL;
+ imo->imo_multicast_addr.s_addr = INADDR_ANY;
+ imo->imo_multicast_vif = -1;
+ imo->imo_multicast_ttl = IP_DEFAULT_MULTICAST_TTL;
+ imo->imo_multicast_loop = IP_DEFAULT_MULTICAST_LOOP;
+ imo->imo_num_memberships = 0;
+
+ INP_LOCK(inp);
+ if (inp->inp_moptions != NULL) {
+ free(imo, M_IPMOPTS);
+ return (inp->inp_moptions);
+ }
+ inp->inp_moptions = imo;
+ return (imo);
+}
+
+/*
* Set the IP multicast options in response to user setsockopt().
*/
static int
@@ -1585,26 +1619,6 @@
int ifindex;
int s;
- imo = inp->inp_moptions;
- if (imo == NULL) {
- /*
- * No multicast option buffer attached to the pcb;
- * allocate one and initialize to default values.
- */
- imo = (struct ip_moptions*)malloc(sizeof(*imo), M_IPMOPTS,
- M_WAITOK);
-
- if (imo == NULL)
- return (ENOBUFS);
- inp->inp_moptions = imo;
- imo->imo_multicast_ifp = NULL;
- imo->imo_multicast_addr.s_addr = INADDR_ANY;
- imo->imo_multicast_vif = -1;
- imo->imo_multicast_ttl = IP_DEFAULT_MULTICAST_TTL;
- imo->imo_multicast_loop = IP_DEFAULT_MULTICAST_LOOP;
- imo->imo_num_memberships = 0;
- }
-
switch (sopt->sopt_name) {
/* store an index number for the vif you wanna use in the send */
case IP_MULTICAST_VIF:
@@ -1619,7 +1633,9 @@
error = EINVAL;
break;
}
+ imo = ip_findmoptions(inp);
imo->imo_multicast_vif = i;
+ INP_UNLOCK(inp);
break;
case IP_MULTICAST_IF:
@@ -1634,8 +1650,10 @@
* When no interface is selected, a default one is
* chosen every time a multicast packet is sent.
*/
+ imo = ip_findmoptions(inp);
if (addr.s_addr == INADDR_ANY) {
imo->imo_multicast_ifp = NULL;
+ INP_UNLOCK(inp);
break;
}
/*
@@ -1646,6 +1664,7 @@
s = splimp();
ifp = ip_multicast_if(&addr, &ifindex);
if (ifp == NULL || (ifp->if_flags & IFF_MULTICAST) == 0) {
+ INP_UNLOCK(inp);
splx(s);
error = EADDRNOTAVAIL;
break;
@@ -1655,6 +1674,7 @@
imo->imo_multicast_addr = addr;
else
imo->imo_multicast_addr.s_addr = INADDR_ANY;
+ INP_UNLOCK(inp);
splx(s);
break;
@@ -1670,7 +1690,9 @@
error = sooptcopyin(sopt, &ttl, 1, 1);
if (error)
break;
+ imo = ip_findmoptions(inp);
imo->imo_multicast_ttl = ttl;
+ INP_UNLOCK(inp);
} else {
u_int ttl;
error = sooptcopyin(sopt, &ttl, sizeof ttl,
@@ -1679,8 +1701,11 @@
break;
if (ttl > 255)
error = EINVAL;
- else
+ else {
+ imo = ip_findmoptions(inp);
imo->imo_multicast_ttl = ttl;
+ INP_UNLOCK(inp);
+ }
}
break;
@@ -1696,14 +1721,18 @@
error = sooptcopyin(sopt, &loop, 1, 1);
if (error)
break;
+ imo = ip_findmoptions(inp);
imo->imo_multicast_loop = !!loop;
+ INP_UNLOCK(inp);
} else {
u_int loop;
error = sooptcopyin(sopt, &loop, sizeof loop,
sizeof loop);
if (error)
break;
+ imo = ip_findmoptions(inp);
imo->imo_multicast_loop = !!loop;
+ INP_UNLOCK(inp);
}
break;
@@ -1757,6 +1786,7 @@
* See if the membership already exists or if all the
* membership slots are full.
*/
+ imo = ip_findmoptions(inp);
for (i = 0; i < imo->imo_num_memberships; ++i) {
if (imo->imo_membership[i]->inm_ifp == ifp &&
imo->imo_membership[i]->inm_addr.s_addr
@@ -1764,11 +1794,13 @@
break;
}
if (i < imo->imo_num_memberships) {
+ INP_UNLOCK(inp);
error = EADDRINUSE;
splx(s);
break;
}
if (i == IP_MAX_MEMBERSHIPS) {
+ INP_UNLOCK(inp);
error = ETOOMANYREFS;
splx(s);
break;
@@ -1779,11 +1811,13 @@
*/
if ((imo->imo_membership[i] =
in_addmulti(&mreq.imr_multiaddr, ifp)) == NULL) {
+ INP_UNLOCK(inp);
error = ENOBUFS;
splx(s);
break;
}
++imo->imo_num_memberships;
+ INP_UNLOCK(inp);
splx(s);
break;
@@ -1819,6 +1853,7 @@
/*
* Find the membership in the membership array.
*/
+ imo = ip_findmoptions(inp);
for (i = 0; i < imo->imo_num_memberships; ++i) {
if ((ifp == NULL ||
imo->imo_membership[i]->inm_ifp == ifp) &&
@@ -1827,6 +1862,7 @@
break;
}
if (i == imo->imo_num_memberships) {
+ INP_UNLOCK(inp);
error = EADDRNOTAVAIL;
splx(s);
break;
@@ -1842,6 +1878,7 @@
for (++i; i < imo->imo_num_memberships; ++i)
imo->imo_membership[i-1] = imo->imo_membership[i];
--imo->imo_num_memberships;
+ INP_UNLOCK(inp);
splx(s);
break;
@@ -1850,18 +1887,6 @@
break;
}
- /*
- * If all options have default values, no need to keep the mbuf.
- */
- if (imo->imo_multicast_ifp == NULL &&
- imo->imo_multicast_vif == -1 &&
- imo->imo_multicast_ttl == IP_DEFAULT_MULTICAST_TTL &&
- imo->imo_multicast_loop == IP_DEFAULT_MULTICAST_LOOP &&
- imo->imo_num_memberships == 0) {
- free(inp->inp_moptions, M_IPMOPTS);
- inp->inp_moptions = NULL;
- }
-
return (error);
}
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