The need for separate bpf and routing message buffers was eliminated

when dhclient moved to processing the entire buffer rather than trying
to process one packet per dispatch() loop.

So use ifi->rbuf for both purposes, resizing it during initialization
to accommodate the larger of the routing socket read size or the bpf
socket read size.

Eliminates a calloc()/free() per routing socket read.

3 files changed, 25 insertions, 21 deletions

diff --git a/sbin/dhclient/dhclient.c b/sbin/dhclient/dhclient.c
index 6eebe98b658..32e7f3002a1 100644
--- a/sbin/dhclient/dhclient.c
+++ b/sbin/dhclient/dhclient.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: dhclient.c,v 1.598 2018/12/28 16:01:39 krw Exp $	*/
+/*	$OpenBSD: dhclient.c,v 1.599 2019/01/03 16:42:30 krw Exp $	*/
 
 /*
  * Copyright 2004 Henning Brauer <henning@openbsd.org>
@@ -311,19 +311,16 @@ void
 routefd_handler(struct interface_info *ifi, int routefd)
 {
 	struct rt_msghdr		*rtm;
-	char				*buf, *lim, *next;
+	unsigned char			*buf = ifi->rbuf;
+	unsigned char			*lim, *next;
 	ssize_t				 n;
 
-	buf = calloc(1, 2048);
-	if (buf == NULL)
-		fatal("rtm buf");
-
 	do {
-		n = read(routefd, buf, 2048);
+		n = read(routefd, buf, RT_BUF_SIZE);
 	} while (n == -1 && errno == EINTR);
 	if (n == -1) {
 		log_warn("%s: routing socket", log_procname);
-		goto done;
+		return;
 	}
 	if (n == 0)
 		fatalx("%s: routing socket closed", log_procname);
@@ -340,10 +337,6 @@ routefd_handler(struct interface_info *ifi, int routefd)
 
 		rtm_dispatch(ifi, rtm);
 	}
-
-done:
-	free(buf);
-	return;
 }
 
 void
@@ -465,7 +458,9 @@ main(int argc, char *argv[])
 	struct interface_info	*ifi;
 	struct passwd		*pw;
 	char			*ignore_list = NULL;
+	unsigned char		*newp;
 	ssize_t			 tailn;
+	size_t			 newsize;
 	int			 fd, socket_fd[2];
 	int			 rtfilter, ioctlfd, routefd, tailfd;
 	int			 ch;
@@ -657,6 +652,12 @@ main(int argc, char *argv[])
 	    sizeof(ifi->rdomain)) == -1)
 		fatal("setsockopt(ROUTE_TABLEFILTER)");
 
+	/* Allocate a rbuf large enough to handle routing socket messages. */
+	ifi->rbuf_max = RT_BUF_SIZE;
+	ifi->rbuf = malloc(ifi->rbuf_max);
+	if (ifi->rbuf == NULL)
+		fatal("rbuf");
+
 	take_charge(ifi, routefd);
 
 	if ((fd = open(path_lease_db,
@@ -679,15 +680,16 @@ main(int argc, char *argv[])
 			fatal("fopen(%s)", path_option_db);
 	}
 
-	/* Register the interface. */
+	/* Create the udp and bpf sockets, growing rbuf if needed. */
 	ifi->udpfd = get_udp_sock(ifi->rdomain);
 	ifi->bpffd = get_bpf_sock(ifi->name);
-	ifi->rbuf_max = configure_bpf_sock(ifi->bpffd);
-	ifi->rbuf = malloc(ifi->rbuf_max);
-	if (ifi->rbuf == NULL)
-		fatal("bpf input buffer");
-	ifi->rbuf_offset = 0;
-	ifi->rbuf_len = 0;
+	newsize = configure_bpf_sock(ifi->bpffd);
+	if (newsize > ifi->rbuf_max) {
+		if ((newp = realloc(ifi->rbuf, newsize)) == NULL)
+			fatal("rbuf");
+		ifi->rbuf = newp;
+		ifi->rbuf_max = newsize;
+	}
 
 	if (chroot(_PATH_VAREMPTY) == -1)
 		fatal("chroot(%s)", _PATH_VAREMPTY);
diff --git a/sbin/dhclient/dhcpd.h b/sbin/dhclient/dhcpd.h
index c41af58886a..c2874e89c10 100644
--- a/sbin/dhclient/dhcpd.h
+++ b/sbin/dhclient/dhcpd.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: dhcpd.h,v 1.261 2018/12/27 17:33:15 krw Exp $	*/
+/*	$OpenBSD: dhcpd.h,v 1.262 2019/01/03 16:42:30 krw Exp $	*/
 
 /*
  * Copyright (c) 2004 Henning Brauer <henning@openbsd.org>
@@ -43,6 +43,7 @@
 #define	REMOTE_PORT	67
 #define	INTERNALSIG	SIG_ATOMIC_MAX
 #define DB_TIMEFMT	"%w %Y/%m/%d %T UTC"
+#define	RT_BUF_SIZE	2048
 
 struct option_data {
 	unsigned int	 len;
diff --git a/sbin/dhclient/dispatch.c b/sbin/dhclient/dispatch.c
index b0a16406c08..80c081f0c71 100644
--- a/sbin/dhclient/dispatch.c
+++ b/sbin/dhclient/dispatch.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: dispatch.c,v 1.155 2018/12/27 17:19:56 krw Exp $	*/
+/*	$OpenBSD: dispatch.c,v 1.156 2019/01/03 16:42:30 krw Exp $	*/
 
 /*
  * Copyright 2004 Henning Brauer <henning@openbsd.org>
@@ -168,6 +168,7 @@ dispatch(struct interface_info *ifi, int routefd)
 			continue;
 
 		if ((fds[0].revents & POLLIN) != 0) {
+			ifi->rbuf_offset = ifi->rbuf_len = 0;
 			do {
 				bpffd_handler(ifi);
 			} while (quit == 0 && ifi->rbuf_offset < ifi->rbuf_len);