netlink: fix ifconfig P2P inet ADDR ADDR netmask 255.255.255.255 addition

Adding P2P addresses is complex in both ioctl and Netlink.
In the ioctl interface, "broadcast" field is the same field as the
"peer". In is possible to specify non-p2p address for the p2p
 interface in IPv6, but not in IPv4.
In the Netlink interface, "address" field means "peer" address.
As a result, a common notion for the Netlink users is to submit
 same address/peer for non-P2P interfaces.

This change customises mapping the attribute on per-family basis.
Specifically,
for IPv4 - if the interface is P2P, assume "address" is p2p and
 "local" is the address. If the interfase is non-p2p, use "local"
 attribute as the address. If it's not set, use "address" attribute.
for IPv6 - start with "local" attribute as the address. If it's not set,
 use use "address" attribute. If both are set and both are the same,
 assume non p2p, otherwise add as p2p.

MFC after:	2 weeks
Reported by:	jkim

1 files changed, 76 insertions, 56 deletions

diff --git a/sys/netlink/route/iface.c b/sys/netlink/route/iface.c
index e40d7097ca61..2f70325ce9ef 100644
--- a/sys/netlink/route/iface.c
+++ b/sys/netlink/route/iface.c
@@ -685,8 +685,8 @@ struct nl_parsed_ifa {
 	uint32_t		ifa_flags;
 	uint32_t		ifaf_vhid;
 	uint32_t		ifaf_flags;
-	struct sockaddr		*ifa_addr;
-	struct sockaddr		*ifa_dst;
+	struct sockaddr		*ifa_address;
+	struct sockaddr		*ifa_local;
 	struct sockaddr		*ifa_broadcast;
 	struct ifa_cacheinfo	*ifa_cacheinfo;
 	struct sockaddr		*f_ifa_addr;
@@ -723,8 +723,8 @@ static const struct nlattr_parser nla_p_ifa_fbsd[] = {
 NL_DECLARE_ATTR_PARSER(ifa_fbsd_parser, nla_p_ifa_fbsd);
 
 static const struct nlattr_parser nla_p_ifa[] = {
-	{ .type = IFA_ADDRESS, .off = _OUT(ifa_addr), .cb = nlattr_get_ip },
-	{ .type = IFA_LOCAL, .off = _OUT(ifa_dst), .cb = nlattr_get_ip },
+	{ .type = IFA_ADDRESS, .off = _OUT(ifa_address), .cb = nlattr_get_ip },
+	{ .type = IFA_LOCAL, .off = _OUT(ifa_local), .cb = nlattr_get_ip },
 	{ .type = IFA_BROADCAST, .off = _OUT(ifa_broadcast), .cb = nlattr_get_ip },
 	{ .type = IFA_CACHEINFO, .off = _OUT(ifa_cacheinfo), .cb = nlattr_get_cinfo },
 	{ .type = IFA_FLAGS, .off = _OUT(ifa_flags), .cb = nlattr_get_uint32 },
@@ -738,39 +738,15 @@ post_p_ifa(void *_attrs, struct nl_pstate *npt)
 {
 	struct nl_parsed_ifa *attrs = (struct nl_parsed_ifa *)_attrs;
 
-	if (!check_sa_family(attrs->ifa_addr, attrs->ifa_family, "IFA_ADDRESS", npt))
+	if (!check_sa_family(attrs->ifa_address, attrs->ifa_family, "IFA_ADDRESS", npt))
 		return (false);
-	if (!check_sa_family(attrs->ifa_dst, attrs->ifa_family, "IFA_LOCAL", npt))
+	if (!check_sa_family(attrs->ifa_local, attrs->ifa_family, "IFA_LOCAL", npt))
 		return (false);
 	if (!check_sa_family(attrs->ifa_broadcast, attrs->ifa_family, "IFA_BROADADDR", npt))
 		return (false);
 
-	set_scope6(attrs->ifa_addr, attrs->ifa_index);
-	set_scope6(attrs->ifa_dst, attrs->ifa_index);
-
-	/*
-	 * Map the Netlink attributes to FreeBSD ifa layout.
-	 * If only IFA_ADDRESS or IFA_LOCAL is set OR
-	 * both are set to the same value => ifa is not broadcast
-	 * and the attribute value contains interface address.
-	 *
-	 * Otherwise (both IFA_ADDRESS and IFA_LOCAL are set and
-	 * different), IFA_LOCAL contains an interface address and
-	 * IFA_ADDRESS contains peer address.
-	 */
-	struct sockaddr *addr, *dst;
-
-	addr = attrs->ifa_addr;
-	if ((dst = attrs->ifa_dst) != NULL) {
-		if (addr != NULL && !sa_equal(addr, dst)) {
-			/* Ptp address */
-			attrs->ifa_addr = dst;
-			attrs->ifa_dst = addr;
-		} else {
-			attrs->ifa_addr = dst;
-			attrs->ifa_dst = NULL;
-		}
-	}
+	set_scope6(attrs->ifa_address, attrs->ifa_index);
+	set_scope6(attrs->ifa_local, attrs->ifa_index);
 
 	return (true);
 }
@@ -1098,6 +1074,7 @@ handle_newaddr_inet(struct nlmsghdr *hdr, struct nl_parsed_ifa *attrs,
 {
 	int plen = attrs->ifa_prefixlen;
 	int if_flags = if_getflags(ifp);
+	struct sockaddr_in *addr, *dst;
 
 	if (plen > 32) {
 		nlmsg_report_err_msg(npt, "invalid ifa_prefixlen");
@@ -1105,29 +1082,45 @@ handle_newaddr_inet(struct nlmsghdr *hdr, struct nl_parsed_ifa *attrs,
 	};
 
 	if (if_flags & IFF_POINTOPOINT) {
-		if (attrs->ifa_addr == NULL || attrs->ifa_dst == NULL) {
+		/*
+		 * Only P2P IFAs are allowed by the implementation.
+		 */
+		if (attrs->ifa_address == NULL || attrs->ifa_local == NULL) {
 			nlmsg_report_err_msg(npt, "Empty IFA_LOCAL/IFA_ADDRESS");
 			return (EINVAL);
 		}
+		addr = (struct sockaddr_in *)attrs->ifa_local;
+		dst = (struct sockaddr_in *)attrs->ifa_address;
 	} else {
-		if (attrs->ifa_addr == NULL) {
+		/*
+		 * Map the Netlink attributes to FreeBSD ifa layout.
+		 * If only IFA_ADDRESS or IFA_LOCAL is set OR
+		 * both are set to the same value => ifa is not p2p
+		 * and the attribute value contains interface address.
+		 *
+		 * Otherwise (both IFA_ADDRESS and IFA_LOCAL are set and
+		 * different), IFA_LOCAL contains an interface address and
+		 * IFA_ADDRESS contains peer address.
+		 */
+		addr = (struct sockaddr_in *)attrs->ifa_local;
+		if (addr == NULL)
+			addr = (struct sockaddr_in *)attrs->ifa_address;
+
+		if (addr == NULL) {
 			nlmsg_report_err_msg(npt, "Empty IFA_LOCAL/IFA_ADDRESS");
 			return (EINVAL);
 		}
-		attrs->ifa_dst = attrs->ifa_broadcast;
 
 		/* Generate broadcast address if not set */
-		if ((if_flags & IFF_BROADCAST) && attrs->ifa_dst == NULL) {
+		if ((if_flags & IFF_BROADCAST) && attrs->ifa_broadcast == NULL) {
 			uint32_t s_baddr;
 			struct sockaddr_in *sin_brd;
 
 			if (plen == 31)
 				s_baddr = INADDR_BROADCAST; /* RFC 3021 */
 			else {
-				struct sockaddr_in *addr;
 				uint32_t s_mask;
 
-				addr = (struct sockaddr_in *)attrs->ifa_addr;
 				s_mask = htonl(plen ? ~((1 << (32 - plen)) - 1) : 0);
 				s_baddr = addr->sin_addr.s_addr | ~s_mask;
 			}
@@ -1138,8 +1131,9 @@ handle_newaddr_inet(struct nlmsghdr *hdr, struct nl_parsed_ifa *attrs,
 			sin_brd->sin_family = AF_INET;
 			sin_brd->sin_len = sizeof(*sin_brd);
 			sin_brd->sin_addr.s_addr = s_baddr;
-			attrs->ifa_dst = (struct sockaddr *)sin_brd;
+			attrs->ifa_broadcast = (struct sockaddr *)sin_brd;
 		}
+		dst = (struct sockaddr_in *)attrs->ifa_broadcast;
 	}
 
 	struct sockaddr_in mask = {
@@ -1148,12 +1142,12 @@ handle_newaddr_inet(struct nlmsghdr *hdr, struct nl_parsed_ifa *attrs,
 		.sin_addr.s_addr = htonl(plen ? ~((1 << (32 - plen)) - 1) : 0),
 	};
 	struct in_aliasreq req = {
-		.ifra_addr = *((struct sockaddr_in *)attrs->ifa_addr),
+		.ifra_addr = *addr,
 		.ifra_mask = mask,
 		.ifra_vhid = attrs->ifaf_vhid,
 	};
-	if (attrs->ifa_dst != NULL)
-		req.ifra_dstaddr = *((struct sockaddr_in *)attrs->ifa_dst);
+	if (dst != NULL)
+		req.ifra_dstaddr = *dst;
 
 	return (in_control(NULL, SIOCAIFADDR, &req, ifp, curthread));
 }
@@ -1162,14 +1156,17 @@ static int
 handle_deladdr_inet(struct nlmsghdr *hdr, struct nl_parsed_ifa *attrs,
     struct ifnet *ifp, struct nlpcb *nlp, struct nl_pstate *npt)
 {
-	if (attrs->ifa_addr == NULL) {
+	struct sockaddr_in *addr = (struct sockaddr_in *)attrs->ifa_local;
+
+	if (addr == NULL)
+		addr = (struct sockaddr_in *)attrs->ifa_address;
+
+	if (addr == NULL) {
 		nlmsg_report_err_msg(npt, "empty IFA_ADDRESS/IFA_LOCAL");
 		return (EINVAL);
 	}
 
-	struct in_aliasreq req = {
-		.ifra_addr = *((struct sockaddr_in *)attrs->ifa_addr),
-	};
+	struct in_aliasreq req = { .ifra_addr = *addr };
 
 	return (in_control(NULL, SIOCDIFADDR, &req, ifp, curthread));
 }
@@ -1180,18 +1177,38 @@ static int
 handle_newaddr_inet6(struct nlmsghdr *hdr, struct nl_parsed_ifa *attrs,
     struct ifnet *ifp, struct nlpcb *nlp, struct nl_pstate *npt)
 {
+	struct sockaddr_in6 *addr, *dst;
+
 	if (attrs->ifa_prefixlen > 128) {
 		nlmsg_report_err_msg(npt, "invalid ifa_prefixlen");
 		return (EINVAL);
 	}
 
-	if (attrs->ifa_addr == NULL) {
+	/*
+	 * In IPv6 implementation, adding non-P2P address to the P2P interface
+	 * is allowed.
+	 */
+	addr = (struct sockaddr_in6 *)(attrs->ifa_local);
+	dst = (struct sockaddr_in6 *)(attrs->ifa_address);
+
+	if (addr == NULL) {
+		addr = dst;
+		dst = NULL;
+	} else if (dst != NULL) {
+		if (IN6_ARE_ADDR_EQUAL(&addr->sin6_addr, &dst->sin6_addr)) {
+			/*
+			 * Sometimes Netlink users fills in both attributes
+			 * with the same address. It still means "non-p2p".
+			 */
+			dst = NULL;
+		}
+	}
+
+	if (addr == NULL) {
 		nlmsg_report_err_msg(npt, "Empty IFA_LOCAL/IFA_ADDRESS");
 		return (EINVAL);
 	}
 
-	/* TODO: Clarify addition of prefixes on p2p interfaces w/o ifa_dst */
-
 	uint32_t flags = nl_flags_to_in6(attrs->ifa_flags) | attrs->ifaf_flags;
 
 	uint32_t pltime = 0, vltime = 0;
@@ -1207,14 +1224,14 @@ handle_newaddr_inet6(struct nlmsghdr *hdr, struct nl_parsed_ifa *attrs,
 	ip6_writemask(&mask.sin6_addr, attrs->ifa_prefixlen);
 
 	struct in6_aliasreq req = {
-		.ifra_addr = *((struct sockaddr_in6 *)attrs->ifa_addr),
+		.ifra_addr = *addr,
 		.ifra_prefixmask = mask,
 		.ifra_flags = flags,
 		.ifra_lifetime = { .ia6t_vltime = vltime, .ia6t_pltime = pltime },
 		.ifra_vhid = attrs->ifaf_vhid,
 	};
-	if (attrs->ifa_dst != NULL)
-		req.ifra_dstaddr = *((struct sockaddr_in6 *)attrs->ifa_dst);
+	if (dst != NULL)
+		req.ifra_dstaddr = *dst;
 
 	return (in6_control(NULL, SIOCAIFADDR_IN6, &req, ifp, curthread));
 }
@@ -1223,14 +1240,17 @@ static int
 handle_deladdr_inet6(struct nlmsghdr *hdr, struct nl_parsed_ifa *attrs,
     struct ifnet *ifp, struct nlpcb *nlp, struct nl_pstate *npt)
 {
-	if (attrs->ifa_addr == NULL) {
+	struct sockaddr_in6 *addr = (struct sockaddr_in6 *)attrs->ifa_local;
+
+	if (addr == NULL)
+		addr = (struct sockaddr_in6 *)(attrs->ifa_address);
+
+	if (addr == NULL) {
 		nlmsg_report_err_msg(npt, "Empty IFA_LOCAL/IFA_ADDRESS");
 		return (EINVAL);
 	}
 
-	struct in6_aliasreq req = {
-		.ifra_addr = *((struct sockaddr_in6 *)attrs->ifa_addr),
-	};
+	struct in6_aliasreq req = { .ifra_addr = *addr };
 
 	return (in6_control(NULL, SIOCDIFADDR_IN6, &req, ifp, curthread));
 }