Introduce a new NET_RT_IFLISTL API to query the address list. It works

on extended and extensible structs if_msghdrl and ifa_msghdrl.  This
will allow us to extend both the msghdrl structs and eventually if_data
in the future without breaking the ABI.

Bump __FreeBSD_version to allow ports to more easily detect the new API.

Reviewed by:	glebius, brooks
MFC after:	3 days

5 files changed, 277 insertions, 47 deletions

diff --git a/lib/libc/gen/sysctl.3 b/lib/libc/gen/sysctl.3
index a841545..b3737e2 100644
--- a/lib/libc/gen/sysctl.3
+++ b/lib/libc/gen/sysctl.3
@@ -28,7 +28,7 @@
 .\"	@(#)sysctl.3	8.4 (Berkeley) 5/9/95
 .\" $FreeBSD$
 .\"
-.Dd April 25, 2010
+.Dd February 11, 2012
 .Dt SYSCTL 3
 .Os
 .Sh NAME
@@ -554,6 +554,7 @@ The fifth and sixth level names are as follows:
 .It "NET_RT_DUMP	None"
 .It "NET_RT_IFLIST	0 or if_index"
 .It "NET_RT_IFMALIST	0 or if_index"
+.It "NET_RT_IFLISTL	0 or if_index"
 .El
 .Pp
 The
@@ -561,6 +562,19 @@ The
 name returns information about multicast group memberships on all interfaces
 if 0 is specified, or for the interface specified by
 .Va if_index .
+.Pp
+The
+.Dv NET_RT_IFLISTL
+is like
+.Dv NET_RT_IFLIST ,
+just returning message header structs with additional fields allowing the
+interface to be extended without breaking binary compatibility.
+The
+.Dv NET_RT_IFLISTL
+uses 'l' versions of the message header structures:
+.Va struct if_msghdrl
+and
+.Va struct ifa_msghdrl .
 .It Li PF_INET
 Get or set various global information about the IPv4
 (Internet Protocol version 4).
diff --git a/sys/net/if.h b/sys/net/if.h
index a5c0ade..47292cb 100644
--- a/sys/net/if.h
+++ b/sys/net/if.h
@@ -244,6 +244,7 @@ struct if_data {
 /*
  * Message format for use in obtaining information about interfaces
  * from getkerninfo and the routing socket
+ * For the new, extensible interface see struct if_msghdrl below.
  */
 struct if_msghdr {
 	u_short	ifm_msglen;	/* to skip over non-understood messages */
@@ -256,8 +257,34 @@ struct if_msghdr {
 };
 
 /*
+ * The 'l' version shall be used by new interfaces, like NET_RT_IFLISTL.  It is
+ * extensible after ifm_data_off or within ifm_data.  Both the if_msghdr and
+ * if_data now have a member field detailing the struct length in addition to
+ * the routing message length.  Macros are provided to find the start of
+ * ifm_data and the start of the socket address strucutres immediately following
+ * struct if_msghdrl given a pointer to struct if_msghdrl.
+ */
+#define	IF_MSGHDRL_IFM_DATA(_l) \
+    (struct if_data *)((char *)(_l) + (_l)->ifm_data_off)
+#define	IF_MSGHDRL_RTA(_l) \
+    (void *)((uintptr_t)(_l) + (_l)->ifm_len)
+struct if_msghdrl {
+	u_short	ifm_msglen;	/* to skip over non-understood messages */
+	u_char	ifm_version;	/* future binary compatibility */
+	u_char	ifm_type;	/* message type */
+	int	ifm_addrs;	/* like rtm_addrs */
+	int	ifm_flags;	/* value of if_flags */
+	u_short	ifm_index;	/* index for associated ifp */
+	u_short _ifm_spare1;	/* spare space to grow if_index, see if_var.h */
+	u_short	ifm_len;	/* length of if_msghdrl incl. if_data */
+	u_short	ifm_data_off;	/* offset of if_data from beginning */
+	struct	if_data ifm_data;/* statistics and other data about if */
+};
+
+/*
  * Message format for use in obtaining information about interface addresses
  * from getkerninfo and the routing socket
+ * For the new, extensible interface see struct ifa_msghdrl below.
  */
 struct ifa_msghdr {
 	u_short	ifam_msglen;	/* to skip over non-understood messages */
@@ -270,6 +297,33 @@ struct ifa_msghdr {
 };
 
 /*
+ * The 'l' version shall be used by new interfaces, like NET_RT_IFLISTL.  It is
+ * extensible after ifam_metric or within ifam_data.  Both the ifa_msghdrl and
+ * if_data now have a member field detailing the struct length in addition to
+ * the routing message length.  Macros are provided to find the start of
+ * ifm_data and the start of the socket address strucutres immediately following
+ * struct ifa_msghdrl given a pointer to struct ifa_msghdrl.
+ */
+#define	IFA_MSGHDRL_IFAM_DATA(_l) \
+    (struct if_data *)((char *)(_l) + (_l)->ifam_data_off)
+#define	IFA_MSGHDRL_RTA(_l) \
+    (void *)((uintptr_t)(_l) + (_l)->ifam_len)
+struct ifa_msghdrl {
+	u_short	ifam_msglen;	/* to skip over non-understood messages */
+	u_char	ifam_version;	/* future binary compatibility */
+	u_char	ifam_type;	/* message type */
+	int	ifam_addrs;	/* like rtm_addrs */
+	int	ifam_flags;	/* value of ifa_flags */
+	u_short	ifam_index;	/* index for associated ifp */
+	u_short _ifam_spare1;	/* spare space to grow if_index, see if_var.h */
+	u_short	ifam_len;	/* length of ifa_msghdrl incl. if_data */
+	u_short	ifam_data_off;	/* offset of if_data from beginning */
+	int	ifam_metric;	/* value of ifa_metric */
+	struct	if_data ifam_data;/* statistics and other data about if or
+				 * address */
+};
+
+/*
  * Message format for use in obtaining information about multicast addresses
  * from the routing socket
  */
diff --git a/sys/net/rtsock.c b/sys/net/rtsock.c
index b594e9a..43539ba 100644
--- a/sys/net/rtsock.c
+++ b/sys/net/rtsock.c
@@ -115,7 +115,34 @@ struct if_msghdr32 {
 	uint16_t ifm_index;
 	struct	if_data32 ifm_data;
 };
-#endif
+
+struct if_msghdrl32 {
+	uint16_t ifm_msglen;
+	uint8_t	ifm_version;
+	uint8_t	ifm_type;
+	int32_t	ifm_addrs;
+	int32_t	ifm_flags;
+	uint16_t ifm_index;
+	uint16_t _ifm_spare1;
+	uint16_t ifm_len;
+	uint16_t ifm_data_off;
+	struct	if_data32 ifm_data;
+};
+
+struct ifa_msghdrl32 {
+	uint16_t ifam_msglen;
+	uint8_t	ifam_version;
+	uint8_t	ifam_type;
+	int32_t	ifam_addrs;
+	int32_t	ifam_flags;
+	uint16_t ifam_index;
+	uint16_t _ifam_spare1;
+	uint16_t ifam_len;
+	uint16_t ifam_data_off;
+	int32_t	ifam_metric;
+	struct	if_data32 ifam_data;
+};
+#endif /* COMPAT_FREEBSD32 */
 
 MALLOC_DEFINE(M_RTABLE, "routetbl", "routing tables");
 
@@ -1014,6 +1041,9 @@ rt_xaddrs(caddr_t cp, caddr_t cplim, struct rt_addrinfo *rtinfo)
 	return (0);
 }
 
+/*
+ * Used by the routing socket.
+ */
 static struct mbuf *
 rt_msg1(int type, struct rt_addrinfo *rtinfo)
 {
@@ -1081,6 +1111,9 @@ rt_msg1(int type, struct rt_addrinfo *rtinfo)
 	return (m);
 }
 
+/*
+ * Used by the sysctl code and routing socket.
+ */
 static int
 rt_msg2(int type, struct rt_addrinfo *rtinfo, caddr_t cp, struct walkarg *w)
 {
@@ -1094,17 +1127,31 @@ again:
 
 	case RTM_DELADDR:
 	case RTM_NEWADDR:
-		len = sizeof(struct ifa_msghdr);
+		if (w != NULL && w->w_op == NET_RT_IFLISTL) {
+#ifdef COMPAT_FREEBSD32
+			if (w->w_req->flags & SCTL_MASK32)
+				len = sizeof(struct ifa_msghdrl32);
+			else
+#endif
+				len = sizeof(struct ifa_msghdrl);
+		} else
+			len = sizeof(struct ifa_msghdr);
 		break;
 
 	case RTM_IFINFO:
 #ifdef COMPAT_FREEBSD32
 		if (w != NULL && w->w_req->flags & SCTL_MASK32) {
-			len = sizeof(struct if_msghdr32);
+			if (w->w_op == NET_RT_IFLISTL)
+				len = sizeof(struct if_msghdrl32);
+			else
+				len = sizeof(struct if_msghdr32);
 			break;
 		}
 #endif
-		len = sizeof(struct if_msghdr);
+		if (w != NULL && w->w_op == NET_RT_IFLISTL)
+			len = sizeof(struct if_msghdrl);
+		else
+			len = sizeof(struct if_msghdr);
 		break;
 
 	case RTM_NEWMADDR:
@@ -1535,6 +1582,147 @@ copy_ifdata32(struct if_data *src, struct if_data32 *dst)
 #endif
 
 static int
+sysctl_iflist_ifml(struct ifnet *ifp, struct rt_addrinfo *info,
+    struct walkarg *w, int len)
+{
+	struct if_msghdrl *ifm;
+
+#ifdef COMPAT_FREEBSD32
+	if (w->w_req->flags & SCTL_MASK32) {
+		struct if_msghdrl32 *ifm32;
+
+		ifm32 = (struct if_msghdrl32 *)w->w_tmem;
+		ifm32->ifm_addrs = info->rti_addrs;
+		ifm32->ifm_flags = ifp->if_flags | ifp->if_drv_flags;
+		ifm32->ifm_index = ifp->if_index;
+		ifm32->_ifm_spare1 = 0;
+		ifm32->ifm_len = sizeof(*ifm32);
+		ifm32->ifm_data_off = offsetof(struct if_msghdrl32, ifm_data);
+
+		copy_ifdata32(&ifp->if_data, &ifm32->ifm_data);
+		/* Fixup if_data carp(4) vhid. */
+		if (carp_get_vhid_p != NULL)
+			ifm32->ifm_data.ifi_vhid =
+			    (*carp_get_vhid_p)(ifp->if_addr);
+
+		return (SYSCTL_OUT(w->w_req, (caddr_t)ifm32, len));
+	}
+#endif
+	ifm = (struct if_msghdrl *)w->w_tmem;
+	ifm->ifm_addrs = info->rti_addrs;
+	ifm->ifm_flags = ifp->if_flags | ifp->if_drv_flags;
+	ifm->ifm_index = ifp->if_index;
+	ifm->_ifm_spare1 = 0;
+	ifm->ifm_len = sizeof(*ifm);
+	ifm->ifm_data_off = offsetof(struct if_msghdrl, ifm_data);
+
+	ifm->ifm_data = ifp->if_data;
+	/* Fixup if_data carp(4) vhid. */
+	if (carp_get_vhid_p != NULL)
+		ifm->ifm_data.ifi_vhid = (*carp_get_vhid_p)(ifp->if_addr);
+
+	return (SYSCTL_OUT(w->w_req, (caddr_t)ifm, len));
+}
+
+static int
+sysctl_iflist_ifm(struct ifnet *ifp, struct rt_addrinfo *info,
+    struct walkarg *w, int len)
+{
+	struct if_msghdr *ifm;
+
+#ifdef COMPAT_FREEBSD32
+	if (w->w_req->flags & SCTL_MASK32) {
+		struct if_msghdr32 *ifm32;
+
+		ifm32 = (struct if_msghdr32 *)w->w_tmem;
+		ifm32->ifm_addrs = info->rti_addrs;
+		ifm32->ifm_flags = ifp->if_flags | ifp->if_drv_flags;
+		ifm32->ifm_index = ifp->if_index;
+
+		copy_ifdata32(&ifp->if_data, &ifm32->ifm_data);
+		/* Fixup if_data carp(4) vhid. */
+		if (carp_get_vhid_p != NULL)
+			ifm32->ifm_data.ifi_vhid =
+			    (*carp_get_vhid_p)(ifp->if_addr);
+
+		return (SYSCTL_OUT(w->w_req, (caddr_t)ifm32, len));
+	}
+#endif
+	ifm = (struct if_msghdr *)w->w_tmem;
+	ifm->ifm_addrs = info->rti_addrs;
+	ifm->ifm_flags = ifp->if_flags | ifp->if_drv_flags;
+	ifm->ifm_index = ifp->if_index;
+
+	ifm->ifm_data = ifp->if_data;
+	/* Fixup if_data carp(4) vhid. */
+	if (carp_get_vhid_p != NULL)
+		ifm->ifm_data.ifi_vhid = (*carp_get_vhid_p)(ifp->if_addr);
+
+	return (SYSCTL_OUT(w->w_req, (caddr_t)ifm, len));
+}
+
+static int
+sysctl_iflist_ifaml(struct ifaddr *ifa, struct rt_addrinfo *info,
+    struct walkarg *w, int len)
+{
+	struct ifa_msghdrl *ifam;
+
+#ifdef COMPAT_FREEBSD32
+	if (w->w_req->flags & SCTL_MASK32) {
+		struct ifa_msghdrl32 *ifam32;
+
+		ifam32 = (struct ifa_msghdrl32 *)w->w_tmem;
+		ifam32->ifam_addrs = info->rti_addrs;
+		ifam32->ifam_flags = ifa->ifa_flags;
+		ifam32->ifam_index = ifa->ifa_ifp->if_index;
+		ifam32->_ifam_spare1 = 0;
+		ifam32->ifam_len = sizeof(*ifam32);
+		ifam32->ifam_data_off =
+		    offsetof(struct ifa_msghdrl32, ifam_data);
+		ifam32->ifam_metric = ifa->ifa_metric;
+
+		copy_ifdata32(&ifa->ifa_ifp->if_data, &ifam32->ifam_data);
+		/* Fixup if_data carp(4) vhid. */
+		if (carp_get_vhid_p != NULL)
+			ifam32->ifam_data.ifi_vhid = (*carp_get_vhid_p)(ifa);
+
+		return (SYSCTL_OUT(w->w_req, (caddr_t)ifam32, len));
+	}
+#endif
+
+	ifam = (struct ifa_msghdrl *)w->w_tmem;
+	ifam->ifam_addrs = info->rti_addrs;
+	ifam->ifam_flags = ifa->ifa_flags;
+	ifam->ifam_index = ifa->ifa_ifp->if_index;
+	ifam->_ifam_spare1 = 0;
+	ifam->ifam_len = sizeof(*ifam);
+	ifam->ifam_data_off = offsetof(struct ifa_msghdrl, ifam_data);
+	ifam->ifam_metric = ifa->ifa_metric;
+
+	ifam->ifam_data = ifa->if_data;
+	/* Fixup if_data carp(4) vhid. */
+	if (carp_get_vhid_p != NULL)
+		ifam->ifam_data.ifi_vhid = (*carp_get_vhid_p)(ifa);
+
+	return (SYSCTL_OUT(w->w_req, w->w_tmem, len));
+}
+
+static int
+sysctl_iflist_ifam(struct ifaddr *ifa, struct rt_addrinfo *info,
+    struct walkarg *w, int len)
+{
+	struct ifa_msghdr *ifam;
+
+	ifam = (struct ifa_msghdr *)w->w_tmem;
+	ifam->ifam_addrs = info->rti_addrs;
+	ifam->ifam_flags = ifa->ifa_flags;
+	ifam->ifam_index = ifa->ifa_ifp->if_index;
+	ifam->ifam_metric = ifa->ifa_metric;
+
+	return (SYSCTL_OUT(w->w_req, w->w_tmem, len));
+}
+
+static int
 sysctl_iflist(int af, struct walkarg *w)
 {
 	struct ifnet *ifp;
@@ -1553,38 +1741,10 @@ sysctl_iflist(int af, struct walkarg *w)
 		len = rt_msg2(RTM_IFINFO, &info, NULL, w);
 		info.rti_info[RTAX_IFP] = NULL;
 		if (w->w_req && w->w_tmem) {
-			struct if_msghdr *ifm;
-
-#ifdef COMPAT_FREEBSD32
-			if (w->w_req->flags & SCTL_MASK32) {
-				struct if_msghdr32 *ifm32;
-
-				ifm32 = (struct if_msghdr32 *)w->w_tmem;
-				ifm32->ifm_index = ifp->if_index;
-				ifm32->ifm_flags = ifp->if_flags |
-				    ifp->if_drv_flags;
-				copy_ifdata32(&ifp->if_data, &ifm32->ifm_data);
-				if (carp_get_vhid_p != NULL)
-					ifm32->ifm_data.ifi_vhid =
-					    (*carp_get_vhid_p)(ifa);
-				ifm32->ifm_addrs = info.rti_addrs;
-				error = SYSCTL_OUT(w->w_req, (caddr_t)ifm32,
-				    len);
-				goto sysctl_out;
-			}
-#endif
-			ifm = (struct if_msghdr *)w->w_tmem;
-			ifm->ifm_index = ifp->if_index;
-			ifm->ifm_flags = ifp->if_flags | ifp->if_drv_flags;
-			ifm->ifm_data = ifp->if_data;
-			if (carp_get_vhid_p != NULL)
-				ifm->ifm_data.ifi_vhid =
-				    (*carp_get_vhid_p)(ifa);
-			ifm->ifm_addrs = info.rti_addrs;
-			error = SYSCTL_OUT(w->w_req, (caddr_t)ifm, len);
-#ifdef COMPAT_FREEBSD32
-		sysctl_out:
-#endif
+			if (w->w_op == NET_RT_IFLISTL)
+				error = sysctl_iflist_ifml(ifp, &info, w, len);
+			else
+				error = sysctl_iflist_ifm(ifp, &info, w, len);
 			if (error)
 				goto done;
 		}
@@ -1599,14 +1759,12 @@ sysctl_iflist(int af, struct walkarg *w)
 			info.rti_info[RTAX_BRD] = ifa->ifa_dstaddr;
 			len = rt_msg2(RTM_NEWADDR, &info, NULL, w);
 			if (w->w_req && w->w_tmem) {
-				struct ifa_msghdr *ifam;
-
-				ifam = (struct ifa_msghdr *)w->w_tmem;
-				ifam->ifam_index = ifa->ifa_ifp->if_index;
-				ifam->ifam_flags = ifa->ifa_flags;
-				ifam->ifam_metric = ifa->ifa_metric;
-				ifam->ifam_addrs = info.rti_addrs;
-				error = SYSCTL_OUT(w->w_req, w->w_tmem, len);
+				if (w->w_op == NET_RT_IFLISTL)
+					error = sysctl_iflist_ifaml(ifa, &info,
+					    w, len);
+				else
+					error = sysctl_iflist_ifam(ifa, &info,
+					    w, len);
 				if (error)
 					goto done;
 			}
@@ -1736,6 +1894,7 @@ sysctl_rtsock(SYSCTL_HANDLER_ARGS)
 		break;
 
 	case NET_RT_IFLIST:
+	case NET_RT_IFLISTL:
 		error = sysctl_iflist(af, &w);
 		break;
 
diff --git a/sys/sys/param.h b/sys/sys/param.h
index 11421a5..bebec50 100644
--- a/sys/sys/param.h
+++ b/sys/sys/param.h
@@ -58,7 +58,7 @@
  *		in the range 5 to 9.
  */
 #undef __FreeBSD_version
-#define __FreeBSD_version 1000007	/* Master, propagated to newvers */
+#define __FreeBSD_version 1000008	/* Master, propagated to newvers */
 
 /*
  * __FreeBSD_kernel__ indicates that this system uses the kernel of FreeBSD,
diff --git a/sys/sys/socket.h b/sys/sys/socket.h
index 7800c42..6b84667 100644
--- a/sys/sys/socket.h
+++ b/sys/sys/socket.h
@@ -396,7 +396,9 @@ struct sockproto {
 #define NET_RT_FLAGS	2		/* by flags, e.g. RESOLVING */
 #define NET_RT_IFLIST	3		/* survey interface list */
 #define	NET_RT_IFMALIST	4		/* return multicast address list */
-#define	NET_RT_MAXID	5
+#define	NET_RT_IFLISTL	5		/* Survey interface list, using 'l'en
+					 * versions of msghdr structs. */
+#define	NET_RT_MAXID	6
 
 #define CTL_NET_RT_NAMES { \
 	{ 0, 0 }, \
@@ -404,6 +406,7 @@ struct sockproto {
 	{ "flags", CTLTYPE_STRUCT }, \
 	{ "iflist", CTLTYPE_STRUCT }, \
 	{ "ifmalist", CTLTYPE_STRUCT }, \
+	{ "iflist2", CTLTYPE_STRUCT }, \
 }
 #endif /* __BSD_VISIBLE */