From 247f8f74e75cf3c56d4d87841ac102f53d1ba76e Mon Sep 17 00:00:00 2001
From: pkelsey <pkelsey@FreeBSD.org>
Date: Mon, 28 Jan 2019 20:30:04 +0000
Subject: [PATCH] Speed up non-status operations applied to a single interface

When performing a non-status operation on a single interface, it is
not necessary for ifconfig to build a list of all addresses in the
system, sort them, then iterate through them looking for the entry for
the single interface of interest. Doing so becomes increasingly
expensive as the number of interfaces in the system grows (e.g., in a
system with 1000+ vlan(4) interfaces).

Reviewed by:	ae, kp
MFC after:	1 week
Sponsored by:	RG Nets
Differential Revision:	https://reviews.freebsd.org/D18919
---
 sbin/ifconfig/ifconfig.c | 57 +++++++++++++++++++++++++++++++++-------
 1 file changed, 48 insertions(+), 9 deletions(-)

diff --git a/sbin/ifconfig/ifconfig.c b/sbin/ifconfig/ifconfig.c
index d9cc46e0ec68..95ef3b065c8c 100644
--- a/sbin/ifconfig/ifconfig.c
+++ b/sbin/ifconfig/ifconfig.c
@@ -111,6 +111,8 @@ static	void status(const struct afswtch *afp, const struct sockaddr_dl *sdl,
 static	void tunnel_status(int s);
 static _Noreturn void usage(void);
 
+static int getifflags(const char *ifname, int us);
+
 static struct afswtch *af_getbyname(const char *name);
 static struct afswtch *af_getbyfamily(int af);
 static void af_other_status(int);
@@ -369,6 +371,7 @@ main(int argc, char *argv[])
 	const char *ifname;
 	struct option *p;
 	size_t iflen;
+	int flags;
 
 	all = downonly = uponly = namesonly = noload = verbose = 0;
 	f_inet = f_inet6 = f_ether = f_addr = NULL;
@@ -526,6 +529,25 @@ main(int argc, char *argv[])
 			argc--, argv++;
 	}
 
+	/*
+	 * Check for a requested configuration action on a single interface,
+	 * which doesn't require building, sorting, and searching the entire
+	 * system address list
+	 */
+	if ((argc > 0) && (ifname != NULL)) {
+		iflen = strlcpy(name, ifname, sizeof(name));
+		if (iflen >= sizeof(name)) {
+			warnx("%s: interface name too long, skipping", ifname);
+		} else {
+			flags = getifflags(name, -1);
+			if (!(((flags & IFF_CANTCONFIG) != 0) ||
+				(downonly && (flags & IFF_UP) != 0) ||
+				(uponly && (flags & IFF_UP) == 0)))
+				ifconfig(argc, argv, 0, afp);
+		}
+		goto done;
+	}
+
 	if (getifaddrs(&ifap) != 0)
 		err(EXIT_FAILURE, "getifaddrs");
 
@@ -609,6 +631,7 @@ main(int argc, char *argv[])
 		printf("\n");
 	freeifaddrs(ifap);
 
+done:
 	freeformat();
 	exit(exit_code);
 }
@@ -1020,6 +1043,28 @@ setifdstaddr(const char *addr, int param __unused, int s,
 		afp->af_getaddr(addr, DSTADDR);
 }
 
+static int
+getifflags(const char *ifname, int us)
+{
+	struct ifreq my_ifr;
+	int s;
+	
+	memset(&my_ifr, 0, sizeof(my_ifr));
+	(void) strlcpy(my_ifr.ifr_name, ifname, sizeof(my_ifr.ifr_name));
+	if (us < 0) {
+		if ((s = socket(AF_LOCAL, SOCK_DGRAM, 0)) < 0)
+			err(1, "socket(family AF_LOCAL,SOCK_DGRAM");
+	} else
+		s = us;
+ 	if (ioctl(s, SIOCGIFFLAGS, (caddr_t)&my_ifr) < 0) {
+ 		Perror("ioctl (SIOCGIFFLAGS)");
+ 		exit(1);
+ 	}
+	if (us < 0)
+		close(s);
+	return ((my_ifr.ifr_flags & 0xffff) | (my_ifr.ifr_flagshigh << 16));
+}
+
 /*
  * Note: doing an SIOCIGIFFLAGS scribbles on the union portion
  * of the ifreq structure, which may confuse other parts of ifconfig.
@@ -1031,20 +1076,14 @@ setifflags(const char *vname, int value, int s, const struct afswtch *afp)
 	struct ifreq		my_ifr;
 	int flags;
 
-	memset(&my_ifr, 0, sizeof(my_ifr));
-	(void) strlcpy(my_ifr.ifr_name, name, sizeof(my_ifr.ifr_name));
-
- 	if (ioctl(s, SIOCGIFFLAGS, (caddr_t)&my_ifr) < 0) {
- 		Perror("ioctl (SIOCGIFFLAGS)");
- 		exit(1);
- 	}
-	flags = (my_ifr.ifr_flags & 0xffff) | (my_ifr.ifr_flagshigh << 16);
-
+	flags = getifflags(name, s);
 	if (value < 0) {
 		value = -value;
 		flags &= ~value;
 	} else
 		flags |= value;
+	memset(&my_ifr, 0, sizeof(my_ifr));
+	(void) strlcpy(my_ifr.ifr_name, name, sizeof(my_ifr.ifr_name));
 	my_ifr.ifr_flags = flags & 0xffff;
 	my_ifr.ifr_flagshigh = flags >> 16;
 	if (ioctl(s, SIOCSIFFLAGS, (caddr_t)&my_ifr) < 0)