netlink: add snl(3) default parsers for routes and links.

This change adds the "default" parsers of _all_ route/link attributes
 exported by the kernel.
It removes the need to declare similar parsers in the userland applications,
 simplifying their logic.

Differential Revision: https://reviews.freebsd.org/D38979
MFC after:	2 weeks

3 files changed, 249 insertions, 0 deletions

diff --git a/sys/netlink/netlink_snl.h b/sys/netlink/netlink_snl.h
index 19b3e2f985f3..4e6524783310 100644
--- a/sys/netlink/netlink_snl.h
+++ b/sys/netlink/netlink_snl.h
@@ -518,6 +518,20 @@ snl_attr_get_nla(struct snl_state *ss __unused, struct nlattr *nla,
 	return (true);
 }
 
+static inline bool
+snl_attr_copy_struct(struct snl_state *ss, struct nlattr *nla,
+    const void *arg __unused, void *target)
+{
+	void *ptr = snl_allocz(ss, NLA_DATA_LEN(nla));
+
+	if (ptr != NULL) {
+		memcpy(ptr, NLA_DATA(nla), NLA_DATA_LEN(nla));
+		*((void **)target) = ptr;
+		return (true);
+	}
+	return (false);
+}
+
 static inline void
 snl_field_get_uint8(struct snl_state *ss __unused, void *src, void *target)
 {
diff --git a/sys/netlink/netlink_snl_route_parsers.h b/sys/netlink/netlink_snl_route_parsers.h
new file mode 100644
index 000000000000..a76fb7da8ec2
--- /dev/null
+++ b/sys/netlink/netlink_snl_route_parsers.h
@@ -0,0 +1,222 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
+ *
+ * Copyright (c) 2023 Alexander V. Chernikov <melifaro@FreeBSD.org>
+ *
+ * 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``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 THE AUTHOR 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.
+ */
+#ifndef	_NETLINK_NETLINK_SNL_ROUTE_PARSERS_H_
+#define	_NETLINK_NETLINK_SNL_ROUTE_PARSERS_H_
+
+#include <netlink/netlink_snl.h>
+#include <netlink/netlink_route.h>
+
+/* TODO: this file should be generated automatically */
+
+/* RTM_<NEW|DEL|GET>ROUTE message parser */
+
+struct rta_mpath_nh {
+	struct sockaddr	*gw;
+	uint32_t	ifindex;
+	uint8_t		rtnh_flags;
+	uint8_t		rtnh_weight;
+	uint32_t	rtax_mtu;
+	uint32_t	rta_rtflags;
+};
+
+#define	_IN(_field)	offsetof(struct rtnexthop, _field)
+#define	_OUT(_field)	offsetof(struct rta_mpath_nh, _field)
+static const struct snl_attr_parser _nla_p_mp_nh_metrics[] = {
+	{ .type = NL_RTAX_MTU, .off = _OUT(rtax_mtu), .cb = snl_attr_get_uint32 },
+};
+SNL_DECLARE_ATTR_PARSER(_metrics_mp_nh_parser, _nla_p_mp_nh_metrics);
+
+static const struct snl_attr_parser _nla_p_mp_nh[] = {
+	{ .type = NL_RTA_GATEWAY, .off = _OUT(gw), .cb = snl_attr_get_ip },
+	{ .type = NL_RTA_METRICS, .arg = &_metrics_mp_nh_parser, .cb = snl_attr_get_nested },
+	{ .type = NL_RTA_RTFLAGS, .off = _OUT(rta_rtflags), .cb = snl_attr_get_uint32 },
+	{ .type = NL_RTA_VIA, .off = _OUT(gw), .cb = snl_attr_get_ipvia },
+};
+
+static const struct snl_field_parser _fp_p_mp_nh[] = {
+	{ .off_in = _IN(rtnh_flags), .off_out = _OUT(rtnh_flags), .cb = snl_field_get_uint8 },
+	{ .off_in = _IN(rtnh_hops), .off_out = _OUT(rtnh_weight), .cb = snl_field_get_uint8 },
+	{ .off_in = _IN(rtnh_ifindex), .off_out = _OUT(ifindex), .cb = snl_field_get_uint32 },
+};
+#undef _IN
+#undef _OUT
+SNL_DECLARE_PARSER(_mpath_nh_parser, struct rtnexthop, _fp_p_mp_nh, _nla_p_mp_nh);
+
+struct rta_mpath {
+	int num_nhops;
+	struct rta_mpath_nh nhops[0];
+};
+
+static bool
+nlattr_get_multipath(struct snl_state *ss, struct nlattr *nla, const void *arg, void *target)
+{
+	int data_len = nla->nla_len - sizeof(struct nlattr);
+	struct rtnexthop *rtnh;
+
+	int max_nhops = data_len / sizeof(struct rtnexthop);
+	size_t sz = (max_nhops + 2) * sizeof(struct rta_mpath_nh);
+
+	struct rta_mpath *mp = snl_allocz(ss, sz);
+	mp->num_nhops = 0;
+
+	for (rtnh = (struct rtnexthop *)(nla + 1); data_len > 0; ) {
+		struct rta_mpath_nh *mpnh = &mp->nhops[mp->num_nhops++];
+
+		if (!snl_parse_header(ss, rtnh, rtnh->rtnh_len, &_mpath_nh_parser, mpnh))
+			return (false);
+
+		int len = NL_ITEM_ALIGN(rtnh->rtnh_len);
+		data_len -= len;
+		rtnh = (struct rtnexthop *)((char *)rtnh + len);
+	}
+	if (data_len != 0 || mp->num_nhops == 0) {
+		return (false);
+	}
+
+	*((struct rta_mpath **)target) = mp;
+	return (true);
+}
+
+struct snl_parsed_route {
+	struct sockaddr		*rta_dst;
+	struct sockaddr		*rta_gw;
+	struct nlattr		*rta_metrics;
+	struct rta_mpath	*rta_multipath;
+	uint32_t		rta_expires;
+	uint32_t		rta_oif;
+	uint32_t		rta_expire;
+	uint32_t		rta_table;
+	uint32_t		rta_knh_id;
+	uint32_t		rta_nh_id;
+	uint32_t		rta_rtflags;
+	uint32_t		rtax_mtu;
+	uint32_t		rtax_weight;
+	uint8_t			rtm_family;
+	uint8_t			rtm_type;
+	uint8_t			rtm_protocol;
+	uint8_t			rtm_dst_len;
+};
+
+#define	_IN(_field)	offsetof(struct rtmsg, _field)
+#define	_OUT(_field)	offsetof(struct snl_parsed_route, _field)
+static const struct snl_attr_parser _nla_p_rtmetrics[] = {
+	{ .type = NL_RTAX_MTU, .off = _OUT(rtax_mtu), .cb = snl_attr_get_uint32 },
+};
+SNL_DECLARE_ATTR_PARSER(_metrics_parser, _nla_p_rtmetrics);
+
+static const struct snl_attr_parser _nla_p_route[] = {
+	{ .type = NL_RTA_DST, .off = _OUT(rta_dst), .cb = snl_attr_get_ip },
+	{ .type = NL_RTA_OIF, .off = _OUT(rta_oif), .cb = snl_attr_get_uint32 },
+	{ .type = NL_RTA_GATEWAY, .off = _OUT(rta_gw), .cb = snl_attr_get_ip },
+	{ .type = NL_RTA_METRICS, .arg = &_metrics_parser, .cb = snl_attr_get_nested },
+	{ .type = NL_RTA_MULTIPATH, .off = _OUT(rta_multipath), .cb = nlattr_get_multipath },
+	{ .type = NL_RTA_KNH_ID, .off = _OUT(rta_knh_id), .cb = snl_attr_get_uint32 },
+	{ .type = NL_RTA_WEIGHT, .off = _OUT(rtax_weight), .cb = snl_attr_get_uint32 },
+	{ .type = NL_RTA_RTFLAGS, .off = _OUT(rta_rtflags), .cb = snl_attr_get_uint32 },
+	{ .type = NL_RTA_TABLE, .off = _OUT(rta_table), .cb = snl_attr_get_uint32 },
+	{ .type = NL_RTA_VIA, .off = _OUT(rta_gw), .cb = snl_attr_get_ipvia },
+	{ .type = NL_RTA_EXPIRES, .off = _OUT(rta_expire), .cb = snl_attr_get_uint32 },
+	{ .type = NL_RTA_NH_ID, .off = _OUT(rta_nh_id), .cb = snl_attr_get_uint32 },
+};
+
+static const struct snl_field_parser _fp_p_route[] = {
+	{.off_in = _IN(rtm_family), .off_out = _OUT(rtm_family), .cb = snl_field_get_uint8 },
+	{.off_in = _IN(rtm_type), .off_out = _OUT(rtm_type), .cb = snl_field_get_uint8 },
+	{.off_in = _IN(rtm_protocol), .off_out = _OUT(rtm_protocol), .cb = snl_field_get_uint8 },
+	{.off_in = _IN(rtm_dst_len), .off_out = _OUT(rtm_dst_len), .cb = snl_field_get_uint8 },
+};
+#undef _IN
+#undef _OUT
+SNL_DECLARE_PARSER(snl_rtm_route_parser, struct rtmsg, _fp_p_route, _nla_p_route);
+
+/* RTM_<NEW|DEL|GET>LINK message parser */
+struct snl_parsed_link {
+	uint32_t			ifi_index;
+	uint32_t			ifi_flags;
+	uint32_t			ifi_change;
+	uint16_t			ifi_type;
+	uint8_t				ifla_operstate;
+	uint8_t				ifla_carrier;
+	uint32_t			ifla_mtu;
+	char				*ifla_ifname;
+	struct nlattr			*ifla_address;
+	struct nlattr			*ifla_broadcast;
+	char				*ifla_ifalias;
+	uint32_t			ifla_promiscuity;
+	struct rtnl_link_stats64	*ifla_stats64;
+};
+
+#define	_IN(_field)	offsetof(struct ifinfomsg, _field)
+#define	_OUT(_field)	offsetof(struct snl_parsed_link, _field)
+static const struct snl_attr_parser _nla_p_link[] = {
+	{ .type = IFLA_ADDRESS, .off = _OUT(ifla_address), .cb = snl_attr_get_nla },
+	{ .type = IFLA_BROADCAST, .off = _OUT(ifla_broadcast), .cb = snl_attr_get_nla },
+	{ .type = IFLA_IFNAME, .off = _OUT(ifla_ifname), .cb = snl_attr_get_string },
+	{ .type = IFLA_MTU, .off = _OUT(ifla_mtu), .cb = snl_attr_get_uint32 },
+	{ .type = IFLA_OPERSTATE, .off = _OUT(ifla_operstate), .cb = snl_attr_get_uint8 },
+	{ .type = IFLA_IFALIAS, .off = _OUT(ifla_ifalias), .cb = snl_attr_get_string },
+	{ .type = IFLA_STATS64, .off = _OUT(ifla_stats64), .cb = snl_attr_copy_struct },
+	{ .type = IFLA_PROMISCUITY, .off = _OUT(ifla_promiscuity), .cb = snl_attr_get_uint32 },
+	{ .type = IFLA_CARRIER, .off = _OUT(ifla_carrier), .cb = snl_attr_get_uint8 },
+};
+static const struct snl_field_parser _fp_p_link[] = {
+	{.off_in = _IN(ifi_index), .off_out = _OUT(ifi_index), .cb = snl_field_get_uint32 },
+	{.off_in = _IN(ifi_flags), .off_out = _OUT(ifi_flags), .cb = snl_field_get_uint32 },
+	{.off_in = _IN(ifi_change), .off_out = _OUT(ifi_change), .cb = snl_field_get_uint32 },
+	{.off_in = _IN(ifi_type), .off_out = _OUT(ifi_type), .cb = snl_field_get_uint16 },
+};
+#undef _IN
+#undef _OUT
+SNL_DECLARE_PARSER(snl_rtm_link_parser, struct ifinfomsg, _fp_p_link, _nla_p_link);
+
+struct snl_parsed_link_simple {
+	uint32_t		ifi_index;
+	uint32_t		ifla_mtu;
+	uint16_t		ifi_type;
+	char			*ifla_ifname;
+};
+
+#define	_IN(_field)	offsetof(struct ifinfomsg, _field)
+#define	_OUT(_field)	offsetof(struct snl_parsed_link_simple, _field)
+static struct snl_attr_parser _nla_p_link_s[] = {
+	{ .type = IFLA_IFNAME, .off = _OUT(ifla_ifname), .cb = snl_attr_get_string },
+	{ .type = IFLA_MTU, .off = _OUT(ifla_mtu), .cb = snl_attr_get_uint32 },
+};
+static struct snl_field_parser _fp_p_link_s[] = {
+	{.off_in = _IN(ifi_index), .off_out = _OUT(ifi_index), .cb = snl_field_get_uint32 },
+	{.off_in = _IN(ifi_type), .off_out = _OUT(ifi_type), .cb = snl_field_get_uint16 },
+};
+#undef _IN
+#undef _OUT
+SNL_DECLARE_PARSER(snl_rtm_link_parser_simple, struct ifinfomsg, _fp_p_link_s, _nla_p_link_s);
+
+static const struct snl_hdr_parser *snl_all_route_parsers[] = {
+	&_metrics_mp_nh_parser, &_mpath_nh_parser, &_metrics_parser, &snl_rtm_route_parser,
+	&snl_rtm_link_parser, &snl_rtm_link_parser_simple,
+};
+
+#endif
diff --git a/tests/sys/netlink/test_snl.c b/tests/sys/netlink/test_snl.c
index d917d81d967d..daacc1aaacec 100644
--- a/tests/sys/netlink/test_snl.c
+++ b/tests/sys/netlink/test_snl.c
@@ -9,6 +9,7 @@
 #include <netlink/netlink_route.h>
 #include "netlink/netlink_snl.h"
 #include "netlink/netlink_snl_route.h"
+#include "netlink/netlink_snl_route_parsers.h"
 
 #include <atf-c.h>
 
@@ -19,6 +20,17 @@ require_netlink(void)
 		atf_tc_skip("netlink module not loaded");
 }
 
+ATF_TC(snl_verify_parsers);
+ATF_TC_HEAD(snl_verify_parsers, tc)
+{
+	atf_tc_set_md_var(tc, "descr", "Tests snl(3) parsers are correct");
+}
+
+ATF_TC_BODY(snl_verify_parsers, tc)
+{
+	SNL_VERIFY_PARSERS(snl_all_route_parsers);
+
+}
 
 ATF_TC(snl_list_ifaces);
 ATF_TC_HEAD(snl_list_ifaces, tc)
@@ -87,6 +99,7 @@ ATF_TC_BODY(snl_list_ifaces, tc)
 ATF_TP_ADD_TCS(tp)
 {
 	ATF_TP_ADD_TC(tp, snl_list_ifaces);
+	ATF_TP_ADD_TC(tp, snl_verify_parsers);
 
 	return (atf_no_error());
 }