Change the API for icmp_do_error so that it takes the mtu directly, rather

than a pointer to struct ifnet containing it.

Saves a 448 byte stack allocation in ip_forward which previously faked up
a struct ifnet just for this purpose.

idea ok deraadt millert

3 files changed, 17 insertions, 29 deletions

diff --git a/sys/netinet/ip_icmp.c b/sys/netinet/ip_icmp.c
index 757a629021c..f82e5ab5fe7 100644
--- a/sys/netinet/ip_icmp.c
+++ b/sys/netinet/ip_icmp.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ip_icmp.c,v 1.67 2005/06/30 08:51:31 markus Exp $	*/
+/*	$OpenBSD: ip_icmp.c,v 1.68 2005/07/31 03:30:55 pascoe Exp $	*/
 /*	$NetBSD: ip_icmp.c,v 1.19 1996/02/13 23:42:22 christos Exp $	*/
 
 /*
@@ -128,8 +128,7 @@ icmp_init(void)
 }
 
 struct mbuf *
-icmp_do_error(struct mbuf *n, int type, int code, n_long dest,
-    struct ifnet *destifp)
+icmp_do_error(struct mbuf *n, int type, int code, n_long dest, int destmtu)
 {
 	struct ip *oip = mtod(n, struct ip *), *nip;
 	unsigned oiplen = oip->ip_hl << 2;
@@ -223,8 +222,8 @@ icmp_do_error(struct mbuf *n, int type, int code, n_long dest,
 			icp->icmp_pptr = code;
 			code = 0;
 		} else if (type == ICMP_UNREACH &&
-		    code == ICMP_UNREACH_NEEDFRAG && destifp)
-			icp->icmp_nextmtu = htons(destifp->if_mtu);
+		    code == ICMP_UNREACH_NEEDFRAG && destmtu)
+			icp->icmp_nextmtu = htons(destmtu);
 	}
 
 	icp->icmp_code = code;
@@ -274,12 +273,11 @@ freeit:
  * The ip packet inside has ip_off and ip_len in host byte order.
  */
 void
-icmp_error(struct mbuf *n, int type, int code, n_long dest,
-    struct ifnet *destifp)
+icmp_error(struct mbuf *n, int type, int code, n_long dest, int destmtu)
 {
 	struct mbuf *m;
 
-	m = icmp_do_error(n, type, code, dest, destifp);
+	m = icmp_do_error(n, type, code, dest, destmtu);
 	if (m != NULL)
 		icmp_reflect(m);
 }
diff --git a/sys/netinet/ip_icmp.h b/sys/netinet/ip_icmp.h
index 33ac0b288f0..1a79d3a06bd 100644
--- a/sys/netinet/ip_icmp.h
+++ b/sys/netinet/ip_icmp.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ip_icmp.h,v 1.20 2003/06/02 23:28:14 millert Exp $	*/
+/*	$OpenBSD: ip_icmp.h,v 1.21 2005/07/31 03:30:55 pascoe Exp $	*/
 /*	$NetBSD: ip_icmp.h,v 1.10 1996/02/13 23:42:28 christos Exp $	*/
 
 /*
@@ -206,8 +206,8 @@ struct icmp {
 
 #ifdef _KERNEL
 struct mbuf *
-	icmp_do_error(struct mbuf *, int, int, n_long, struct ifnet *);
-void	icmp_error(struct mbuf *, int, int, n_long, struct ifnet *);
+	icmp_do_error(struct mbuf *, int, int, n_long, int);
+void	icmp_error(struct mbuf *, int, int, n_long, int);
 void	icmp_input(struct mbuf *, ...);
 void	icmp_init(void);
 void	icmp_reflect(struct mbuf *);
diff --git a/sys/netinet/ip_input.c b/sys/netinet/ip_input.c
index cebb993c66a..63eac232f89 100644
--- a/sys/netinet/ip_input.c
+++ b/sys/netinet/ip_input.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ip_input.c,v 1.129 2005/06/15 07:24:05 markus Exp $	*/
+/*	$OpenBSD: ip_input.c,v 1.130 2005/07/31 03:30:55 pascoe Exp $	*/
 /*	$NetBSD: ip_input.c,v 1.30 1996/03/16 23:53:58 christos Exp $	*/
 
 /*
@@ -1402,13 +1402,9 @@ ip_forward(m, srcrt)
 	struct ip *ip = mtod(m, struct ip *);
 	struct sockaddr_in *sin;
 	struct rtentry *rt;
-	int error, type = 0, code = 0;
+	int error, type = 0, code = 0, destmtu = 0;
 	struct mbuf *mcopy;
 	n_long dest;
-	struct ifnet *destifp;
-#ifdef IPSEC
-	struct ifnet dummyifp;
-#endif
 
 	dest = 0;
 #ifdef DIAGNOSTIC
@@ -1505,7 +1501,6 @@ ip_forward(m, srcrt)
 	}
 	if (mcopy == NULL)
 		return;
-	destifp = NULL;
 
 	switch (error) {
 
@@ -1529,16 +1524,11 @@ ip_forward(m, srcrt)
 #ifdef IPSEC
 		if (ipforward_rt.ro_rt) {
 			struct rtentry *rt = ipforward_rt.ro_rt;
-			destifp = ipforward_rt.ro_rt->rt_ifp;
-			/*
-			 * XXX BUG ALERT
-			 * The "dummyifp" code relies upon the fact
-			 * that icmp_error() touches only ifp->if_mtu.
-			 */
-			if (rt->rt_rmx.rmx_mtu) {
-				dummyifp.if_mtu = rt->rt_rmx.rmx_mtu;
-				destifp = &dummyifp;
-			}
+
+			if (rt->rt_rmx.rmx_mtu)
+				destmtu = rt->rt_rmx.rmx_mtu;
+			else
+				destmtu = ipforward_rt.ro_rt->rt_ifp->if_mtu;
 		}
 #endif /*IPSEC*/
 		ipstat.ips_cantfrag++;
@@ -1562,7 +1552,7 @@ ip_forward(m, srcrt)
 #endif
 	}
 
-	icmp_error(mcopy, type, code, dest, destifp);
+	icmp_error(mcopy, type, code, dest, destmtu);
 }
 
 int