On 05/04/2017 15:43, Robert Elz wrote:
> Date: Wed, 5 Apr 2017 13:25:44 +0100
> From: Roy Marples <[email protected]>
> Message-ID: <[email protected]>
>
>
> | Right now I chose the same API, just so I can test and validate it works
> | the same on both OS's.
>
> That's reaosnable for testing, but preferably not for comitting.
>
> | Also, when NetBSD started it has 11 types. Now it has 21, so that's an
> | extra 10 in 22 years, so at a rate of 1 every 2 years.
>
> Most likely they come in bursts.
>
> | Strictly speaking, the types are beholden to the version so we could
> | just bump the version and remove the O (ie old) compat vars and bury
> | them to keep inside 32-bits. Thus would mean re-working how we handle
> | compat in rtsock though.
>
> We could, but let's not - it is a 256 value field (or 255 since 0 appears
> to not be used) and we should be able to cope with all values, and without
> needing hackery any time in the future.
>
> | Well yes, but the point of the API is that we don't want them by
> | accident,
>
> The scheme I proposed was intended to allow the kernel coder (when/if
> it is required) to arrange to map the message types so that accidents
> would be rare (that is combining in the bitmask values that tend to
> be enabled together, and excluding the types that are not.)
>
> But...
>
> | If avoiding a variable length bitmask is needed then we just need
> | something similar to poll
>
> Yes, that's another option - anything to avoid 1 << 80 and similar...
>
> The mapping scheme (I suggested) is likely cheaper in the kernel (just
> one extra mem reference compared to your/OpenBSD's original during
> packet processing) but a poll style interface is cleaner, and could
> avoid all unwanted packets being delivered.
>
> With the API you proposed in this message, either internel implementation
> could be used, which is good - what matters most is that the application
> sends the actual rtm_type values to the kernel, rather than calculating a
> bitmask and sending that (as unless we do a select type interface, that
> bitmask is of fixed length, and I don't think we want to make it a 32 byte
> array to fit all possible bits in).
>
> For now the kernel (packet processing) code could be just as you showed it
> initially (just a 32 bit mask operation) just as long as the API does not
> expose that.
These are all valid points.
v2 of the patch attached to address.
I changed the socket option name so apps can tell the two
implementations apart.
More comments are welcome.
Roy
Index: share/man/man4/route.4
===================================================================
RCS file: /cvsroot/src/share/man/man4/route.4,v
retrieving revision 1.28
diff -u -p -r1.28 route.4
--- share/man/man4/route.4 21 Sep 2016 10:50:23 -0000 1.28
+++ share/man/man4/route.4 5 Apr 2017 16:44:08 -0000
@@ -29,7 +29,7 @@
.\"
.\" @(#)route.4 8.6 (Berkeley) 4/19/94
.\"
-.Dd September 15, 2016
+.Dd March 5, 2017
.Dt ROUTE 4
.Os
.Sh NAME
@@ -174,6 +174,23 @@ by doing a
.Xr shutdown 2
system call for further input.
.Pp
+A process can specify which route message types it's interested in by passing
+an array of route messsage types to the
+.Xr setsockopt 2
+call with the
+.Dv RO_MSGFILTER
+option at the
+.Dv PF_ROUTE
+level.
+For example, to only get specific messages:
+.Bd -literal -offset indent
+unsigned char rtfilter[] = { RTM_IFINFO, RTM_IFANNOUNCE };
+
+if (setsockopt(routefd, PF_ROUTE, RO_MSGFILTER,
+ &rtfilter, sizeof(rtfilter)) == -1)
+ err(1, "setsockopt(RO_MSGFILTER)");
+.Ed
+.Pp
If a route is in use when it is deleted,
the routing entry will be marked down and removed from the routing table,
but the resources associated with it will not
Index: sys/net/raw_cb.h
===================================================================
RCS file: /cvsroot/src/sys/net/raw_cb.h,v
retrieving revision 1.26
diff -u -p -r1.26 raw_cb.h
--- sys/net/raw_cb.h 20 Jan 2016 21:43:59 -0000 1.26
+++ sys/net/raw_cb.h 5 Apr 2017 16:44:08 -0000
@@ -46,6 +46,8 @@ struct rawcb {
struct sockaddr *rcb_faddr; /* destination address */
struct sockaddr *rcb_laddr; /* socket's address */
struct sockproto rcb_proto; /* protocol family, protocol */
+ int (*rcb_filter)(struct mbuf *, struct sockproto *,
+ struct rawcb *);
size_t rcb_len;
};
Index: sys/net/raw_usrreq.c
===================================================================
RCS file: /cvsroot/src/sys/net/raw_usrreq.c,v
retrieving revision 1.55
diff -u -p -r1.55 raw_usrreq.c
--- sys/net/raw_usrreq.c 20 Jan 2016 21:43:59 -0000 1.55
+++ sys/net/raw_usrreq.c 5 Apr 2017 16:44:08 -0000
@@ -107,6 +107,9 @@ raw_input(struct mbuf *m0, ...)
continue;
if (rp->rcb_faddr && !equal(rp->rcb_faddr, src))
continue;
+ /* Run any filtering that may have been installed. */
+ if (rp->rcb_filter != NULL && rp->rcb_filter(m, proto, rp) != 0)
+ continue;
if (last != NULL) {
struct mbuf *n;
if ((n = m_copy(m, 0, M_COPYALL)) == NULL)
Index: sys/net/route.h
===================================================================
RCS file: /cvsroot/src/sys/net/route.h,v
retrieving revision 1.111
diff -u -p -r1.111 route.h
--- sys/net/route.h 19 Dec 2016 11:17:00 -0000 1.111
+++ sys/net/route.h 5 Apr 2017 16:44:08 -0000
@@ -250,6 +250,11 @@ struct rt_msghdr {
#define RTM_DELADDR 0x17 /* address being removed from iface */
#define RTM_CHGADDR 0x18 /* address properties changed */
+/*
+ * setsockopt defines used for the filtering.
+ */
+#define RO_MSGFILTER 1 /* array of which rtm_type to send to
client */
+
#define RTV_MTU 0x1 /* init or lock _mtu */
#define RTV_HOPCOUNT 0x2 /* init or lock _hopcount */
#define RTV_EXPIRE 0x4 /* init or lock _expire */
Index: sys/net/rtsock.c
===================================================================
RCS file: /cvsroot/src/sys/net/rtsock.c,v
retrieving revision 1.211
diff -u -p -r1.211 rtsock.c
--- sys/net/rtsock.c 24 Mar 2017 03:45:02 -0000 1.211
+++ sys/net/rtsock.c 5 Apr 2017 16:44:09 -0000
@@ -177,6 +177,12 @@ static void rt_adjustcount(int, int);
static const struct protosw COMPATNAME(route_protosw)[];
+struct routecb {
+ struct rawcb rocb_rcb;
+ unsigned int rocb_msgfilter;
+};
+#define sotoroutecb(so) ((struct routecb *)(so)->so_pcb)
+
static void
rt_adjustcount(int af, int cnt)
{
@@ -200,14 +206,48 @@ rt_adjustcount(int af, int cnt)
}
static int
+COMPATNAME(route_filter)(struct mbuf *m, struct sockproto *proto,
+ struct rawcb *rp)
+{
+ struct routecb *rop = (struct routecb *)rp;
+ struct rt_xmsghdr *rtm;
+
+ KASSERT(m != NULL);
+ KASSERT(proto != NULL);
+ KASSERT(rp != NULL);
+
+ /* Wrong family for this socket. */
+ if (proto->sp_family != PF_ROUTE)
+ return ENOPROTOOPT;
+
+ /* If no filter set, just return. */
+ if (rop->rocb_msgfilter == 0)
+ return 0;
+
+ /* Ensure we can access rtm_type */
+ if (m->m_len < offsetof(struct rt_xmsghdr, rtm_type) + 1)
+ return EINVAL;
+
+ rtm = mtod(m, struct rt_xmsghdr *);
+ /* If the rtm type is filtered out, return a positive. */
+ if (!(rop->rocb_msgfilter & (1U << rtm->rtm_type)))
+ return EEXIST;
+
+ /* Passed the filter. */
+ return 0;
+}
+
+static int
COMPATNAME(route_attach)(struct socket *so, int proto)
{
struct rawcb *rp;
+ struct routecb *rop;
int s, error;
KASSERT(sotorawcb(so) == NULL);
- rp = kmem_zalloc(sizeof(*rp), KM_SLEEP);
- rp->rcb_len = sizeof(*rp);
+ rop = kmem_zalloc(sizeof(*rop), KM_SLEEP);
+ rp = &rop->rocb_rcb;
+ rp->rcb_len = sizeof(*rop);
so->so_pcb = rp;
s = splsoftnet();
@@ -215,11 +255,12 @@ COMPATNAME(route_attach)(struct socket *
rt_adjustcount(rp->rcb_proto.sp_protocol, 1);
rp->rcb_laddr = &COMPATNAME(route_info).ri_src;
rp->rcb_faddr = &COMPATNAME(route_info).ri_dst;
+ rp->rcb_filter = COMPATNAME(route_filter);
}
splx(s);
if (error) {
- kmem_free(rp, sizeof(*rp));
+ kmem_free(rop, sizeof(*rop));
so->so_pcb = NULL;
return error;
}
@@ -981,6 +1022,56 @@ out:
return error;
}
+static int
+route_ctloutput(int op, struct socket *so, struct sockopt *sopt)
+{
+ struct routecb *rop = sotoroutecb(so);
+ int error = 0;
+ unsigned char *rtm_type;
+ size_t len;
+ unsigned int msgfilter;
+
+ KASSERT(solocked(so));
+
+ if (sopt->sopt_level != AF_ROUTE) {
+ error = ENOPROTOOPT;
+ } else switch (op) {
+ case PRCO_SETOPT:
+ switch (sopt->sopt_name) {
+ case RO_MSGFILTER:
+ msgfilter = 0;
+ for (rtm_type = sopt->sopt_data, len = sopt->sopt_size;
+ len != 0;
+ rtm_type++, len -= sizeof(*rtm_type))
+ {
+ /* Guard against overflowing our storage. */
+ if (*rtm_type >= sizeof(msgfilter) * CHAR_BIT) {
+ error = EOVERFLOW;
+ break;
+ }
+ msgfilter |= (1U << *rtm_type);
+ }
+ if (error == 0)
+ rop->rocb_msgfilter = msgfilter;
+ break;
+ default:
+ error = ENOPROTOOPT;
+ break;
+ }
+ break;
+ case PRCO_GETOPT:
+ switch (sopt->sopt_name) {
+ case RO_MSGFILTER:
+ error = ENOTSUP;
+ break;
+ default:
+ error = ENOPROTOOPT;
+ break;
+ }
+ }
+ return error;
+}
+
static void
rt_setmetrics(int which, const struct rt_xmsghdr *in, struct rtentry *out)
{
@@ -1946,6 +2037,7 @@ static const struct protosw COMPATNAME(r
.pr_flags = PR_ATOMIC|PR_ADDR,
.pr_input = raw_input,
.pr_ctlinput = raw_ctlinput,
+ .pr_ctloutput = route_ctloutput,
.pr_usrreqs = &route_usrreqs,
.pr_init = raw_init,
},
