Add the userland part of the NET_RT_IFMALIST sysctl MIB. A new function,

getifmaddrs(), is added to retrieve current multicast group memberships.

Reviewed by:	harti

3 files changed, 322 insertions, 2 deletions

diff --git a/lib/libc/net/Makefile.inc b/lib/libc/net/Makefile.inc
index a00269e..6062550 100644
--- a/lib/libc/net/Makefile.inc
+++ b/lib/libc/net/Makefile.inc
@@ -6,7 +6,7 @@
 
 SRCS+=	addr2ascii.c ascii2addr.c base64.c ether_addr.c getaddrinfo.c \
 	gethostbydns.c gethostbyht.c gethostbynis.c gethostnamadr.c \
-	getifaddrs.c getnameinfo.c \
+	getifaddrs.c getifmaddrs.c getnameinfo.c \
 	getnetbydns.c getnetbyht.c getnetbynis.c getnetnamadr.c \
 	getproto.c getprotoent.c getprotoname.c getservbyname.c \
 	getservbyport.c getservent.c herror.c hesiod.c inet_addr.c \
@@ -40,7 +40,7 @@ nslexer.c: nslexer.l nsparser.h
 .endif
 
 MAN+=	addr2ascii.3 byteorder.3 ethers.3 getaddrinfo.3 gethostbyname.3 \
-	getifaddrs.3 getipnodebyname.3 \
+	getifaddrs.3 getifmaddrs.3 getipnodebyname.3 \
 	getnameinfo.3 getnetent.3 getprotoent.3 getservent.3 hesiod.3 \
 	if_indextoname.3 \
 	inet.3 inet_net.3 \
@@ -59,6 +59,7 @@ MLINKS+=gethostbyname.3 endhostent.3 gethostbyname.3 gethostbyaddr.3 \
 	gethostbyname.3 herror.3 gethostbyname.3 hstrerror.3 \
 	gethostbyname.3 sethostent.3
 MLINKS+=getifaddrs.3 freeifaddrs.3
+MLINKS+=getifmaddrs.3 freeifmaddrs.3
 MLINKS+=getipnodebyname.3 getipnodebyaddr.3 getipnodebyname.3 freehostent.3
 MLINKS+=getnetent.3 endnetent.3 getnetent.3 getnetbyaddr.3 \
 	getnetent.3 getnetbyname.3 getnetent.3 setnetent.3
diff --git a/lib/libc/net/getifmaddrs.3 b/lib/libc/net/getifmaddrs.3
new file mode 100644
index 0000000..8594f6b
--- /dev/null
+++ b/lib/libc/net/getifmaddrs.3
@@ -0,0 +1,112 @@
+.\"	$FreeBSD$
+.\"
+.\" Copyright (c) 2003 Bruce M. Simpson. All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY Bruce M. Simpson ``AS IS'' AND
+.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+.\" ARE DISCLAIMED.  IN NO EVENT SHALL Bruce M. Simpson BE LIABLE
+.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+.\" SUCH DAMAGE.
+.Dd October 12, 1995
+.Dt GETIFMADDRS 3
+.Os
+.Sh NAME
+.Nm getifmaddrs
+.Nd get multicast group memberships
+.Sh SYNOPSIS
+.In sys/types.h
+.In sys/socket.h
+.In ifaddrs.h
+.Ft int
+.Fn getifmaddrs "struct ifmaddrs **ifmap"
+.Ft void
+.Fn freeifmaddrs "struct ifmaddrs *ifmp"
+.Sh DESCRIPTION
+The
+.Fn getifmaddrs
+function stores a reference to a linked list of the multicast memberships
+on the local machine in the memory referenced by
+.Fa ifmap .
+The list consists of
+.Nm ifmaddrs
+structures, as defined in the include file
+.Aq Pa ifaddrs.h .
+The
+.Nm ifmaddrs
+structure contains at least the following entries:
+.Bd -literal
+    struct ifmaddrs   *ifma_next;     /* Pointer to next struct */
+    struct sockaddr   *ifma_name;     /* Interface name (AF_LINK) */
+    struct sockaddr   *ifma_addr;     /* Multicast address */
+    struct sockaddr   *ifma_lladdr;   /* Link-layer translation, if any */
+.Ed
+.Pp
+The
+.Li ifma_next
+field contains a pointer to the next structure on the list.
+This field is
+.Dv NULL
+in last structure on the list.
+.Pp
+The
+.Li ifma_name
+field references an AF_LINK address structure, containing the name of the
+interface where the membership exists.
+.Pp
+The
+.Li ifma_addr
+references the address that this membership is for.
+.Pp
+The
+.Li ifma_lladdr
+field references a link-layer translation for the protocol-level address in
+.Li ifma_addr ,
+if one is set, otherwise it is NULL.
+.Pp
+The data returned by
+.Fn getifmaddrs
+is dynamically allocated and should be freed using
+.Fn freeifmaddrs
+when no longer needed.
+.Sh RETURN VALUES
+.Rv -std getifmaddrs
+.Sh ERRORS
+The
+.Fn getifmaddrs
+may fail and set
+.Va errno
+for any of the errors specified for the library routines
+.Xr malloc 3
+or
+.Xr sysctl 3 .
+.Sh BUGS
+If both
+.Aq Pa net/if.h
+and
+.Aq Pa ifaddrs.h
+are being included,
+.Aq Pa net/if.h
+.Em must
+be included before
+.Aq Pa ifaddrs.h .
+.Sh SEE ALSO
+.Xr sysctl 3 ,
+.Xr networking 4 ,
+.Xr ifconfig 8
+.Sh HISTORY
+The
+.Nm
+implementation first appeared in
+.Fx 5.2 .
diff --git a/lib/libc/net/getifmaddrs.c b/lib/libc/net/getifmaddrs.c
new file mode 100644
index 0000000..40475ae
--- /dev/null
+++ b/lib/libc/net/getifmaddrs.c
@@ -0,0 +1,207 @@
+/*
+ * Copyright (c) 2003 Bruce M. Simpson.
+ * All rights reserved
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *        This product includes software developed by Bruce M. Simpson.
+ * 4. Neither the name of Bruce M. Simpson nor the names of other
+ *    contributors may be used to endorse or promote products derived
+ *    from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY BRUCE M. SIMPSON AND AFFILIATES
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL BRUCE M. SIMPSON OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include "namespace.h"
+#include <sys/param.h>
+#include <sys/sysctl.h>
+#include <sys/ioctl.h>
+#include <sys/socket.h>
+#include <net/if.h>
+#include <net/if_dl.h>
+#include <net/route.h>
+
+#include <errno.h>
+#include <ifaddrs.h>
+#include <stdlib.h>
+#include <string.h>
+#include "un-namespace.h"
+
+#define	SALIGN	(sizeof(long) - 1)
+#define	SA_RLEN(sa)	((sa)->sa_len ? (((sa)->sa_len + SALIGN) & ~SALIGN) : \
+			    (SALIGN + 1))
+#define	MAX_SYSCTL_TRY	5
+#define	RTA_MASKS	(RTA_GATEWAY | RTA_IFP | RTA_IFA)
+
+int
+getifmaddrs(struct ifmaddrs **pif)
+{
+	int icnt = 1;
+	int dcnt = 0;
+	int ntry = 0;
+	u_short idx = 0;
+	size_t len;
+	size_t needed;
+	int mib[6];
+	int i;
+	char *buf;
+	char *data;
+	char *names;
+	char *next;
+	char *p;
+	struct ifma_msghdr *ifmam;
+	struct ifmaddrs *ifa, *ift;
+	struct rt_msghdr *rtm;
+	struct sockaddr *sa;
+
+	mib[0] = CTL_NET;
+	mib[1] = PF_ROUTE;
+	mib[2] = 0;             /* protocol */
+	mib[3] = 0;             /* wildcard address family */
+	mib[4] = NET_RT_IFMALIST;
+	mib[5] = 0;             /* no flags */
+	do {
+		if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0)
+			return (-1);
+		if ((buf = malloc(needed)) == NULL)
+			return (-1);
+		if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) {
+			if (errno != ENOMEM || ++ntry >= MAX_SYSCTL_TRY) {
+				free(buf);
+				return (-1);
+			}
+			free(buf);
+			buf = NULL;
+		} 
+	} while (buf == NULL);
+
+	for (next = buf; next < buf + needed; next += rtm->rtm_msglen) {
+		rtm = (struct rt_msghdr *)(void *)next;
+		if (rtm->rtm_version != RTM_VERSION)
+			continue;
+		switch (rtm->rtm_type) {
+		case RTM_NEWMADDR:
+			ifmam = (struct ifma_msghdr *)(void *)rtm;
+			if ((ifmam->ifmam_addrs & RTA_IFA) == 0)
+				break;
+			icnt++;
+			p = (char *)(ifmam + 1);
+			for (i = 0; i < RTAX_MAX; i++) {
+				if ((RTA_MASKS & ifmam->ifmam_addrs &
+				    (1 << i)) == 0)
+					continue;
+				sa = (struct sockaddr *)(void *)p;
+				len = SA_RLEN(sa);
+				dcnt += len;
+				p += len;
+			}
+			break;
+		}
+	}
+
+	data = malloc(sizeof(struct ifmaddrs) * icnt + dcnt);
+	if (data == NULL) {
+		free(buf);
+		return (-1);
+	}
+
+	ifa = (struct ifmaddrs *)(void *)data;
+	data += sizeof(struct ifmaddrs) * icnt;
+	names = data + dcnt;
+
+	memset(ifa, 0, sizeof(struct ifmaddrs) * icnt);
+	ift = ifa;
+
+	idx = 0;
+	for (next = buf; next < buf + needed; next += rtm->rtm_msglen) {
+		rtm = (struct rt_msghdr *)(void *)next;
+		if (rtm->rtm_version != RTM_VERSION)
+			continue;
+
+		switch (rtm->rtm_type) {
+		case RTM_NEWMADDR:
+			ifmam = (struct ifma_msghdr *)(void *)rtm;
+			if ((ifmam->ifmam_addrs & RTA_IFA) == 0)
+				break;
+
+			p = (char *)(ifmam + 1);
+			for (i = 0; i < RTAX_MAX; i++) {
+				if ((RTA_MASKS & ifmam->ifmam_addrs &
+				    (1 << i)) == 0)
+					continue;
+				sa = (struct sockaddr *)(void *)p;
+				len = SA_RLEN(sa);
+				switch (i) {
+				case RTAX_GATEWAY:
+					ift->ifma_lladdr =
+					    (struct sockaddr *)(void *)data;
+					memcpy(data, p, len);
+					data += len;
+					break;
+
+				case RTAX_IFP:
+					ift->ifma_name =
+					    (struct sockaddr *)(void *)data;
+					memcpy(data, p, len);
+					data += len;
+					break;
+
+				case RTAX_IFA:
+					ift->ifma_addr =
+					    (struct sockaddr *)(void *)data;
+					memcpy(data, p, len);
+					data += len;
+					break;
+
+				default:
+					data += len;
+					break;
+				}
+				p += len;
+			}
+			ift->ifma_next = ift + 1;
+			ift = ift->ifma_next;
+			break;
+		}
+	}
+
+	free(buf);
+
+	if (ift > ifa) {
+		ift--;
+		ift->ifma_next = NULL;
+		*pif = ifa;
+	} else {
+		*pif = NULL;
+		free(ifa);
+	}
+	return (0);
+}
+
+void
+freeifmaddrs(struct ifmaddrs *ifmp)
+{
+
+	free(ifmp);
+}