git: aee2f11bf4b4 - main - netstat: simplify netlink route printing code.

From: Alexander V. Chernikov <melifaro_at_FreeBSD.org>
Date: Sat, 18 Mar 2023 13:11:24 UTC
The branch main has been updated by melifaro:

URL: https://cgit.FreeBSD.org/src/commit/?id=aee2f11bf4b44b286a88b6726347bd7466c5e750

commit aee2f11bf4b44b286a88b6726347bd7466c5e750
Author:     Alexander V. Chernikov <melifaro@FreeBSD.org>
AuthorDate: 2023-03-18 13:05:41 +0000
Commit:     Alexander V. Chernikov <melifaro@FreeBSD.org>
CommitDate: 2023-03-18 13:05:41 +0000

    netstat: simplify netlink route printing code.
    
    A number of improvements has commited to snl(3) recently.
    A notable one is snl(3) build-in parsers for all of the objects
     exported by the kernel.
    
    This change updates netlink handling code to the latest available snl(3)
    API.
---
 usr.bin/netstat/route_netlink.c | 207 ++++------------------------------------
 1 file changed, 17 insertions(+), 190 deletions(-)

diff --git a/usr.bin/netstat/route_netlink.c b/usr.bin/netstat/route_netlink.c
index ea50d8076182..3546603ca1cc 100644
--- a/usr.bin/netstat/route_netlink.c
+++ b/usr.bin/netstat/route_netlink.c
@@ -47,6 +47,8 @@ __FBSDID("$FreeBSD$");
 #include <netlink/netlink_route.h>
 #include <netlink/netlink_snl.h>
 #include <netlink/netlink_snl_route.h>
+#include <netlink/netlink_snl_route_parsers.h>
+#include <netlink/netlink_snl_route_compat.h>
 
 #include <netinet/in.h>
 #include <netgraph/ng_socket.h>
@@ -75,25 +77,6 @@ static void p_rtentry_netlink(struct snl_state *ss, const char *name, struct nlm
 static struct ifmap_entry *ifmap;
 static size_t ifmap_size;
 
-struct nl_parsed_link {
-	uint32_t		ifi_index;
-	uint32_t		ifla_mtu;
-	char			*ifla_ifname;
-};
-
-#define	_IN(_field)	offsetof(struct ifinfomsg, _field)
-#define	_OUT(_field)	offsetof(struct nl_parsed_link, _field)
-static struct snl_attr_parser ap_link[] = {
-	{ .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_link[] = {
-	{.off_in = _IN(ifi_index), .off_out = _OUT(ifi_index), .cb = snl_field_get_uint32 },
-};
-#undef _IN
-#undef _OUT
-SNL_DECLARE_PARSER(link_parser, struct ifinfomsg, fp_link, ap_link);
-
 /* Generate ifmap using netlink */
 static struct ifmap_entry *
 prepare_ifmap_netlink(struct snl_state *ss, size_t *pifmap_size)
@@ -108,7 +91,7 @@ prepare_ifmap_netlink(struct snl_state *ss, size_t *pifmap_size)
 	};
 	msg.hdr.nlmsg_len = sizeof(msg);
 
-	if (!snl_send(ss, &msg, sizeof(msg))) {
+	if (!snl_send_message(ss, &msg.hdr)) {
 		snl_free(ss);
 		return (NULL);
 	}
@@ -116,15 +99,12 @@ prepare_ifmap_netlink(struct snl_state *ss, size_t *pifmap_size)
 	struct ifmap_entry *ifmap = NULL;
 	uint32_t ifmap_size = 0;
 	struct nlmsghdr *hdr;
-	while ((hdr = snl_read_message(ss)) != NULL && hdr->nlmsg_type != NLMSG_DONE) {
-		if (hdr->nlmsg_seq != msg.hdr.nlmsg_seq)
-			continue;
-/*
-		if (hdr->nlmsg_type == NLMSG_ERROR)
-			break;
-*/
-		struct nl_parsed_link link = {};
-		if (!snl_parse_nlmsg(ss, hdr, &link_parser, &link))
+	struct snl_errmsg_data e = {};
+
+	while ((hdr = snl_read_reply_multi(ss, msg.hdr.nlmsg_seq, &e)) != NULL) {
+		struct snl_parsed_link_simple link = {};
+
+		if (!snl_parse_nlmsg(ss, hdr, &snl_rtm_link_parser_simple, &link))
 			continue;
 		if (link.ifi_index >= ifmap_size) {
 			size_t size = roundup2(link.ifi_index + 1, 32) * sizeof(struct ifmap_entry);
@@ -144,140 +124,6 @@ prepare_ifmap_netlink(struct snl_state *ss, size_t *pifmap_size)
 	return (ifmap);
 }
 
-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_rtmetrics[] = {
-	{ .type = NL_RTAX_MTU, .off = _OUT(rtax_mtu), .cb = snl_attr_get_uint32 },
-};
-SNL_DECLARE_ATTR_PARSER(metrics_mp_parser, nla_p_mp_rtmetrics);
-
-static const struct snl_attr_parser psnh[] = {
-	{ .type = NL_RTA_GATEWAY, .off = _OUT(gw), .cb = snl_attr_get_ip },
-	{ .type = NL_RTA_METRICS, .arg = &metrics_mp_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 fpnh[] = {
-	{ .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_parser, struct rtnexthop, fpnh, psnh);
-
-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_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 nl_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 nl_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 ps[] = {
-	{ .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 fprt[] = {
-	{.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(rtm_parser, struct rtmsg, fprt, ps);
-
-#define	RTF_UP		0x1
-#define	RTF_GATEWAY	0x2
-#define	RTF_HOST	0x4
-#define	RTF_REJECT	0x8
-#define	RTF_DYNAMIC	0x10
-#define RTF_STATIC	0x800
-#define RTF_BLACKHOLE	0x1000
-#define RTF_PROTO2	0x4000
-#define RTF_PROTO1	0x8000
-#define RTF_PROTO3	0x40000
-#define	RTF_FIXEDMTU	0x80000
-#define RTF_PINNED	0x100000
-
 static void
 ip6_writemask(struct in6_addr *addr6, uint8_t mask)
 {
@@ -309,17 +155,6 @@ gen_mask(int family, int plen, struct sockaddr *sa)
 	}
 }
 
-struct sockaddr_dl_short {
-	u_char	sdl_len;	/* Total length of sockaddr */
-	u_char	sdl_family;	/* AF_LINK */
-	u_short	sdl_index;	/* if != 0, system given index for interface */
-	u_char	sdl_type;	/* interface type */
-	u_char	sdl_nlen;	/* interface name length, no trailing 0 reqd. */
-	u_char	sdl_alen;	/* link level address length */
-	u_char	sdl_slen;	/* link layer selector length */
-	char	sdl_data[8];	/* unused */
-};
-
 static void
 add_scopeid(struct sockaddr *sa, int ifindex)
 {
@@ -331,7 +166,7 @@ add_scopeid(struct sockaddr *sa, int ifindex)
 }
 
 static void
-p_path(struct nl_parsed_route *rt, bool is_mpath)
+p_path(struct snl_parsed_route *rt, bool is_mpath)
 {
 	struct sockaddr_in6 mask6;
 	struct sockaddr *pmask = (struct sockaddr *)&mask6;
@@ -398,8 +233,8 @@ static void
 p_rtentry_netlink(struct snl_state *ss, const char *name, struct nlmsghdr *hdr)
 {
 
-	struct nl_parsed_route rt = {};
-	if (!snl_parse_nlmsg(ss, hdr, &rtm_parser, &rt))
+	struct snl_parsed_route rt = {};
+	if (!snl_parse_nlmsg(ss, hdr, &snl_rtm_route_parser, &rt))
 		return;
 	if (rt.rtax_weight == 0)
 		rt.rtax_weight = rt_default_weight;
@@ -424,9 +259,9 @@ p_rtentry_netlink(struct snl_state *ss, const char *name, struct nlmsghdr *hdr)
 		return;
 	}
 
-	struct sockaddr_dl_short sdl_gw = {
+	struct sockaddr_dl sdl_gw = {
 		.sdl_family = AF_LINK,
-		.sdl_len = sizeof(struct sockaddr_dl_short),
+		.sdl_len = sizeof(struct sockaddr_dl),
 		.sdl_index = rt.rta_oif,
 	};
 	if (rt.rta_gw == NULL)
@@ -438,21 +273,15 @@ p_rtentry_netlink(struct snl_state *ss, const char *name, struct nlmsghdr *hdr)
 	xo_close_instance(name);
 }
 
-static const struct snl_hdr_parser *all_parsers[] = {
-	&link_parser, &metrics_mp_parser, &mpath_parser, &metrics_parser, &rtm_parser
-};
-
 bool
 p_rtable_netlink(int fibnum, int af)
 {
 	int fam = AF_UNSPEC;
 	int need_table_close = false;
 	struct nlmsghdr *hdr;
-
+	struct snl_errmsg_data e = {};
 	struct snl_state ss = {};
 
-	SNL_VERIFY_PARSERS(all_parsers);
-
 	if (!snl_init(&ss, NETLINK_ROUTE))
 		return (false);
 
@@ -474,16 +303,14 @@ p_rtable_netlink(int fibnum, int af)
 	};
 	msg.hdr.nlmsg_len = sizeof(msg);
 
-	if (!snl_send(&ss, &msg, sizeof(msg))) {
+	if (!snl_send_message(&ss, &msg.hdr)) {
 		snl_free(&ss);
 		return (false);
 	}
 
 	xo_open_container("route-table");
 	xo_open_list("rt-family");
-	while ((hdr = snl_read_message(&ss)) != NULL && hdr->nlmsg_type != NLMSG_DONE) {
-		if (hdr->nlmsg_seq != msg.hdr.nlmsg_seq)
-			continue;
+	while ((hdr = snl_read_reply_multi(&ss, msg.hdr.nlmsg_seq, &e)) != NULL) {
 		struct rtmsg *rtm = (struct rtmsg *)(hdr + 1);
 		/* Only print family first time. */
 		if (fam != rtm->rtm_family) {