Rework source IP address setting.

- Move most of the processing out of rtable.c (reasonnable tb@, ok bluhm@)
- Remove memory allocation, store pointer to existing ifaddr
- Fix tunnel interface handling

looks fine mpi@

3 files changed, 52 insertions, 47 deletions

diff --git a/sys/net/rtable.c b/sys/net/rtable.c
index dd8f33af576..9a9f2a65c31 100644
--- a/sys/net/rtable.c
+++ b/sys/net/rtable.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: rtable.c,v 1.71 2020/11/05 10:46:13 denis Exp $ */
+/*	$OpenBSD: rtable.c,v 1.72 2020/11/07 09:51:40 denis Exp $ */
 
 /*
  * Copyright (c) 2014-2016 Martin Pieuchot
@@ -31,10 +31,6 @@
 #include <net/rtable.h>
 #include <net/route.h>
 
-#include <net/if.h>
-#include <net/if_dl.h>
-#include <net/if_var.h>
-
 /*
  * Structures used by rtable_get() to retrieve the corresponding
  * routing table for a given pair of ``af'' and ``rtableid''.
@@ -370,46 +366,14 @@ rtable_alloc(unsigned int rtableid, unsigned int alen, unsigned int off)
 }
 
 int
-rtable_setsource(unsigned int rtableid, struct sockaddr *src)
+rtable_setsource(unsigned int rtableid, int af, struct sockaddr *src)
 {
 	struct art_root		*ar;
 
-	if ((ar = rtable_get(rtableid, src->sa_family)) == NULL)
+	if ((ar = rtable_get(rtableid, af)) == NULL)
 		return (EAFNOSUPPORT);
 
-	/*
-	 * Check if source address is assigned to an interface in the
-	 * same rdomain
-	 */
-	if (ifa_ifwithaddr(src, rtableid) == NULL) {
-		/*
-		 * If source address is 0.0.0.0 or ::
-		 * use automatic source selection
-		 */
-		switch(src->sa_family) {
-		case AF_INET:
-			if(satosin(src)->sin_addr.s_addr == INADDR_ANY)
-				return (EINVAL);
-			break;
-		case AF_INET6:
-			if (IN6_IS_ADDR_UNSPECIFIED(&satosin6(src)->sin6_addr))
-				return (EINVAL);
-			break;
-		default:
-			return (EAFNOSUPPORT);
-		}
-		src = NULL;
-	}
-
-	if (ar->source) {
-	       free(ar->source, M_IFADDR, ar->source->sa_len);
-	       ar->source = NULL;
-	}
-
-	if (src) {
-		ar->source = malloc(src->sa_len, M_IFADDR, M_WAITOK|M_ZERO);
-		memcpy(ar->source, src, src->sa_len);
-	}
+	ar->source = src;
 
 	return (0);
 }
@@ -434,9 +398,7 @@ rtable_clearsource(unsigned int rtableid, struct sockaddr *src)
 	addr = rtable_getsource(rtableid, src->sa_family);
 	if (addr && (addr->sa_len == src->sa_len)) {
 		if (memcmp(src, addr, addr->sa_len) == 0) {
-			memset(addr->sa_data, 0, addr->sa_len-
-			    sizeof(addr->sa_len)-sizeof(addr->sa_family));
-			rtable_setsource(rtableid, addr);
+			rtable_setsource(rtableid, src->sa_family, NULL);
 		}
 	}
 }
diff --git a/sys/net/rtable.h b/sys/net/rtable.h
index 0686d0c75a2..e9dc137918e 100644
--- a/sys/net/rtable.h
+++ b/sys/net/rtable.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: rtable.h,v 1.25 2020/10/29 21:15:27 denis Exp $ */
+/*	$OpenBSD: rtable.h,v 1.26 2020/11/07 09:51:40 denis Exp $ */
 
 /*
  * Copyright (c) 2014-2016 Martin Pieuchot
@@ -39,7 +39,7 @@ unsigned int	 rtable_l2(unsigned int);
 unsigned int	 rtable_loindex(unsigned int);
 void		 rtable_l2set(unsigned int, unsigned int, unsigned int);
 
-int		 rtable_setsource(unsigned int, struct sockaddr *);
+int		 rtable_setsource(unsigned int, int, struct sockaddr *);
 struct sockaddr *rtable_getsource(unsigned int, int);
 void		 rtable_clearsource(unsigned int, struct sockaddr *);
 struct rtentry	*rtable_lookup(unsigned int, struct sockaddr *,
diff --git a/sys/net/rtsock.c b/sys/net/rtsock.c
index bed2efff028..65214a9dd1d 100644
--- a/sys/net/rtsock.c
+++ b/sys/net/rtsock.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: rtsock.c,v 1.303 2020/10/29 21:15:27 denis Exp $	*/
+/*	$OpenBSD: rtsock.c,v 1.304 2020/11/07 09:51:40 denis Exp $	*/
 /*	$NetBSD: rtsock.c,v 1.18 1996/03/29 00:32:10 cgd Exp $	*/
 
 /*
@@ -138,6 +138,8 @@ int		 sysctl_iflist(int, struct walkarg *);
 int		 sysctl_ifnames(struct walkarg *);
 int		 sysctl_rtable_rtstat(void *, size_t *, void *);
 
+int		 rt_setsource(unsigned int, struct sockaddr *);
+
 /*
  * Locks used to protect struct members
  *       I       immutable after creation
@@ -860,7 +862,7 @@ route_output(struct mbuf *m, struct socket *so, struct sockaddr *dstaddr,
 			goto fail;
 		}
 		if ((error =
-		    rtable_setsource(tableid, info.rti_info[RTAX_IFA])) != 0)
+		    rt_setsource(tableid, info.rti_info[RTAX_IFA])) != 0)
 			goto fail;
 	} else {
 		error = rtm_output(rtm, &rt, &info, prio, tableid);
@@ -2076,9 +2078,13 @@ sysctl_source(int af, u_int tableid, struct walkarg *w)
 		case AF_INET:
 			size = sizeof(struct sockaddr_in);
 			break;
+#ifdef INET6
 		case AF_INET6:
 			size = sizeof(struct sockaddr_in6);
 			break;
+#endif
+		default:
+			return (0);
 		}
 		w->w_needed += size;
 		if (w->w_where && w->w_needed <= 0) {
@@ -2307,6 +2313,43 @@ rtm_validate_proposal(struct rt_addrinfo *info)
 	return 0;
 }
 
+int
+rt_setsource(unsigned int rtableid, struct sockaddr *src)
+{
+	struct ifaddr	*ifa;
+	/*
+	 * If source address is 0.0.0.0 or ::
+	 * use automatic source selection
+	 */
+	switch(src->sa_family) {
+	case AF_INET:
+		if(satosin(src)->sin_addr.s_addr == INADDR_ANY) {
+			rtable_setsource(rtableid, AF_INET, NULL);
+			return (0);
+		}
+		break;
+#ifdef INET6
+	case AF_INET6:
+		if (IN6_IS_ADDR_UNSPECIFIED(&satosin6(src)->sin6_addr)) {
+			rtable_setsource(rtableid, AF_INET6, NULL);
+			return (0);
+		}
+		break;
+#endif
+	default:
+		return (EAFNOSUPPORT);
+	}
+
+	/*
+	 * Check if source address is assigned to an interface in the
+	 * same rdomain
+	 */
+	if ((ifa = ifa_ifwithaddr(src, rtableid)) == NULL)
+		return (EINVAL);
+
+	return (rtable_setsource(rtableid, src->sa_family, ifa->ifa_addr));
+}
+
 /*
  * Definitions of protocols supported in the ROUTE domain.
  */