From 055776c84a41bb88c6ccd67615ea172864f6804c Mon Sep 17 00:00:00 2001
From: "Alexander V. Chernikov" <melifaro@FreeBSD.org>
Date: Sat, 4 Mar 2023 15:15:56 +0000
Subject: [PATCH] netlink: use newly-added if_foreach_sleep() to iterate over
 the interface list.

Summary: MFC after:	2 weeks

Subscribers: imp, glebius

Differential Revision: https://reviews.freebsd.org/D38907
---
 sys/netlink/route/iface.c | 56 ++++++++++-----------------------------
 1 file changed, 14 insertions(+), 42 deletions(-)

diff --git a/sys/netlink/route/iface.c b/sys/netlink/route/iface.c
index 116acd863ba9..6704acd1624f 100644
--- a/sys/netlink/route/iface.c
+++ b/sys/netlink/route/iface.c
@@ -360,8 +360,10 @@ static const struct nlattr_parser nla_p_if[] = {
 NL_DECLARE_STRICT_PARSER(ifmsg_parser, struct ifinfomsg, check_ifmsg, nlf_p_if, nla_p_if);
 
 static bool
-match_iface(struct nl_parsed_link *attrs, struct ifnet *ifp)
+match_iface(struct ifnet *ifp, void *_arg)
 {
+	struct nl_parsed_link *attrs = (struct nl_parsed_link *)_arg;
+
 	if (attrs->ifi_index != 0 && attrs->ifi_index != ifp->if_index)
 		return (false);
 	if (attrs->ifi_type != 0 && attrs->ifi_index != ifp->if_type)
@@ -373,6 +375,15 @@ match_iface(struct nl_parsed_link *attrs, struct ifnet *ifp)
 	return (true);
 }
 
+static int
+dump_cb(struct ifnet *ifp, void *_arg)
+{
+	struct netlink_walkargs *wa = (struct netlink_walkargs *)_arg;
+	if (!dump_iface(wa->nw, ifp, &wa->hdr, 0))
+		return (ENOMEM);
+	return (0);
+}
+
 /*
  * {nlmsg_len=52, nlmsg_type=RTM_GETLINK, nlmsg_flags=NLM_F_REQUEST, nlmsg_seq=1662842818, nlmsg_pid=0},
  *  {ifi_family=AF_PACKET, ifi_type=ARPHRD_NETROM, ifi_index=0, ifi_flags=0, ifi_change=0},
@@ -417,7 +428,7 @@ rtnl_handle_getlink(struct nlmsghdr *hdr, struct nlpcb *nlp, struct nl_pstate *n
 		}
 
 		if (ifp != NULL) {
-			if (match_iface(&attrs, ifp)) {
+			if (match_iface(ifp, &attrs)) {
 				if (!dump_iface(wa.nw, ifp, &wa.hdr, 0))
 					error = ENOMEM;
 			} else
@@ -438,46 +449,7 @@ rtnl_handle_getlink(struct nlmsghdr *hdr, struct nlpcb *nlp, struct nl_pstate *n
 	 */
 
 	NL_LOG(LOG_DEBUG2, "Start dump");
-
-	struct ifnet **match_array = NULL;
-	int offset = 0, base_count = 0;
-
-	NLP_LOG(LOG_DEBUG3, nlp, "MATCHING: index=%u type=%d name=%s",
-	    attrs.ifi_index, attrs.ifi_type, attrs.ifla_ifname);
-	NET_EPOCH_ENTER(et);
-        CK_STAILQ_FOREACH(ifp, &V_ifnet, if_link) {
-		wa.count++;
-		if (match_iface(&attrs, ifp)) {
-			if (offset >= base_count) {
-				/* Too many matches, need to reallocate */
-				struct ifnet **new_array;
-				/* Start with 128 bytes, do 2x increase on each realloc */
-				base_count = (base_count != 0) ? base_count * 2 : 16;
-				new_array = malloc(base_count * sizeof(void *), M_TEMP, M_NOWAIT);
-				if (new_array == NULL) {
-					error = ENOMEM;
-					break;
-				}
-				memcpy(new_array, match_array, offset * sizeof(void *));
-				free(match_array, M_TEMP);
-				match_array = new_array;
-			}
-
-			if (if_try_ref(ifp))
-				match_array[offset++] = ifp;
-                }
-        }
-	NET_EPOCH_EXIT(et);
-
-	NL_LOG(LOG_DEBUG2, "Matched %d interface(s), dumping", offset);
-	for (int i = 0; error == 0 && i < offset; i++) {
-		if (!dump_iface(wa.nw, match_array[i], &wa.hdr, 0))
-			error = ENOMEM;
-	}
-	for (int i = 0; i < offset; i++)
-		if_rele(match_array[i]);
-	free(match_array, M_TEMP);
-
+	if_foreach_sleep(match_iface, &attrs, dump_cb, &wa);
 	NL_LOG(LOG_DEBUG2, "End dump, iterated %d dumped %d", wa.count, wa.dumped);
 
 	if (!nlmsg_end_dump(wa.nw, error, &wa.hdr)) {