BSD: don't listen to own route messages

This makes the code a lot simpler and reduces the changes
of overflowing the route socket.

1 files changed, 69 insertions, 96 deletions

diff --git a/src/if-bsd.c b/src/if-bsd.c
index e9ebfdce..68914b87 100644
--- a/src/if-bsd.c
+++ b/src/if-bsd.c
@@ -125,9 +125,7 @@ int
 if_opensockets_os(struct dhcpcd_ctx *ctx)
 {
 	struct priv *priv;
-#ifdef SO_RERROR
-	int on = 1;
-#endif
+	int n;
 #if defined(RO_MSGFILTER) || defined(ROUTE_MSGFILTER)
 	unsigned char msgfilter[] = {
 	    RTM_IFINFO,
@@ -164,12 +162,21 @@ if_opensockets_os(struct dhcpcd_ctx *ctx)
 	if (ctx->link_fd == -1)
 		return -1;
 
+	/* Ignore our own route(4) messages.
+	 * Sadly there is no way of doing this for route(4) messages
+	 * generated from addresses we add/delete. */
+	n = 0;
+	if (setsockopt(ctx->link_fd, SOL_SOCKET, SO_USELOOPBACK,
+	    &n, sizeof(n)) == -1)
+		logerr("%s: SO_USELOOPBACK", __func__);
+
 #ifdef SO_RERROR
 	/* Tell recvmsg(2) to return ENOBUFS if the receiving socket overflows
 	 * from too many route(4) messages so we can re-sync our state
 	 * with reality. */
+	n = 1;
 	if (setsockopt(ctx->link_fd, SOL_SOCKET, SO_RERROR,
-	    &on, sizeof(on)) == -1)
+	    &n, sizeof(n)) == -1)
 		logerr("%s: SO_RERROR", __func__);
 #endif
 
@@ -477,11 +484,6 @@ if_route(unsigned char cmd, const struct rt *rt)
 	assert(rt != NULL);
 	ctx = rt->rt_ifp->ctx;
 
-	if ((cmd == RTM_ADD || cmd == RTM_DELETE || cmd == RTM_CHANGE) &&
-	    ctx->options & DHCPCD_DAEMONISE &&
-	    !(ctx->options & DHCPCD_DAEMONISED))
-		ctx->options |= DHCPCD_RTM_PPID;
-
 #define ADDSA(sa) do {							      \
 		memcpy(bp, (sa), (sa)->sa_len);				      \
 		bp += RT_ROUNDUP((sa)->sa_len);				      \
@@ -596,7 +598,6 @@ if_route(unsigned char cmd, const struct rt *rt)
 	rtm->rtm_msglen = (unsigned short)(bp - (char *)rtm);
 	if (write(ctx->link_fd, rtm, rtm->rtm_msglen) == -1)
 		return -1;
-	ctx->sseq = ctx->seq;
 	return 0;
 }
 
@@ -873,7 +874,6 @@ if_address6(unsigned char cmd, const struct ipv6_addr *ia)
 	    cmd == RTM_DELADDR ? SIOCDIFADDR_IN6 : SIOCAIFADDR_IN6, &ifa);
 }
 
-#if !(defined(HAVE_IFADDRS_ADDRFLAGS) && defined(HAVE_IFAM_ADDRFLAGS))
 int
 if_addrflags6(const struct interface *ifp, const struct in6_addr *addr,
     __unused const char *alias)
@@ -894,7 +894,6 @@ if_addrflags6(const struct interface *ifp, const struct in6_addr *addr,
 		flags = -1;
 	return flags;
 }
-#endif
 
 int
 if_getlifetime6(struct ipv6_addr *ia)
@@ -975,43 +974,11 @@ if_ifinfo(struct dhcpcd_ctx *ctx, const struct if_msghdr *ifm)
 	    (unsigned int)ifm->ifm_flags, ifp->name);
 }
 
-static int
-if_ownmsgpid(struct dhcpcd_ctx *ctx, pid_t pid, int seq)
-{
-
-	/* Ignore messages generated by us */
-	if (getpid() == pid) {
-		ctx->options &= ~DHCPCD_RTM_PPID;
-		return 1;
-	}
-
-	/* Ignore messages sent by the parent after forking */
-	if ((ctx->options &
-	    (DHCPCD_RTM_PPID | DHCPCD_DAEMONISED)) ==
-	    (DHCPCD_RTM_PPID | DHCPCD_DAEMONISED) &&
-	    ctx->ppid == pid)
-	{
-		/* If this is the last successful message sent,
-		 * clear the check flag as it's possible another
-		 * process could re-use the same pid and also
-		 * manipulate the routing table. */
-		if (ctx->pseq == seq)
-			ctx->options &= ~DHCPCD_RTM_PPID;
-		return 1;
-	}
-
-	/* Not a message we made. */
-	return 0;
-}
-
 static void
 if_rtm(struct dhcpcd_ctx *ctx, const struct rt_msghdr *rtm)
 {
 	struct rt rt;
 
-	if (if_ownmsgpid(ctx, rtm->rtm_pid, rtm->rtm_seq))
-		return;
-
 	/* Ignore errors. */
 	if (rtm->rtm_errno != 0)
 		return;
@@ -1058,26 +1025,6 @@ if_ifa(struct dhcpcd_ctx *ctx, const struct ifa_msghdr *ifam)
 		return;
 
 #ifdef HAVE_IFAM_PID
-	if (if_ownmsgpid(ctx, ifam->ifam_pid, 0)) {
-#ifdef HAVE_IFAM_ADDRFLAGS
-		/* If the kernel isn't doing DAD for the newly added
-		 * address we need to let it through. */
-		if (ifam->ifam_type != RTM_NEWADDR)
-			return;
-		switch (rti_info[RTAX_IFA]->sa_family) {
-		case AF_INET:
-			if (ifam->ifam_addrflags & IN_IFF_TENTATIVE)
-				return;
-			break;
-		case AF_INET6:
-			if (ifam->ifam_addrflags & IN6_IFF_TENTATIVE)
-				return;
-			break;
-		default:
-			return;
-		}
-#endif
-	}
 	pid = ifam->ifam_pid;
 #else
 	pid = 0;
@@ -1115,12 +1062,27 @@ if_ifa(struct dhcpcd_ctx *ctx, const struct ifa_msghdr *ifam)
 		sin = (const void *)rti_info[RTAX_NETMASK];
 		mask.s_addr = sin != NULL && sin->sin_family == AF_INET ?
 		    sin->sin_addr.s_addr : INADDR_ANY;
+		sin = (const void *)rti_info[RTAX_BRD];
+		bcast.s_addr = sin != NULL && sin->sin_family == AF_INET ?
+		    sin->sin_addr.s_addr : INADDR_ANY;
 
 #if defined(__NetBSD_Version__) && __NetBSD_Version__ < 800000000
-		/* NetBSD-7 and older send an invalid broadcast address.
+		/*
+		 * NetBSD-7 and older send an invalid broadcast address.
 		 * So we need to query the actual address to get
-		 * the right one. */
+		 * the right one.
+		 */
 		{
+#else
+		/*
+		 * If the address was deleted, lets check if it's
+		 * a late message and it still exists (maybe modified).
+		 * If so, ignore it as deleting an address causes
+		 * dhcpcd to drop any lease to which it belongs.
+		 */
+		if (ifam->ifam_type == RTM_DELADDR) {
+#endif
+#ifdef SIOCGIFALIAS
 			struct in_aliasreq ifra;
 
 			memset(&ifra, 0, sizeof(ifra));
@@ -1132,38 +1094,38 @@ if_ifa(struct dhcpcd_ctx *ctx, const struct ifa_msghdr *ifam)
 			if (ioctl(ctx->pf_inet_fd, SIOCGIFALIAS, &ifra) == -1) {
 				if (errno != EADDRNOTAVAIL)
 					logerr("%s: SIOCGIFALIAS", __func__);
-				break;
+				if (ifam->ifam_type != RTM_DELADDR)
+					break;
 			}
-			bcast = ifra.ifra_broadaddr.sin_addr;
-		}
-#else
-		sin = (const void *)rti_info[RTAX_BRD];
-		bcast.s_addr = sin != NULL && sin->sin_family == AF_INET ?
-		    sin->sin_addr.s_addr : INADDR_ANY;
+#if defined(__NetBSD_Version__) && __NetBSD_Version__ < 800000000
+			else
+				bcast = ifra.ifra_broadaddr.sin_addr;
 #endif
-
-#if defined(__FreeBSD__) || defined(__DragonFly__)
-		/* FreeBSD sends RTM_DELADDR for each assigned address
-		 * to an interface just brought down.
-		 * This is wrong, because the address still exists.
-		 * So we need to ignore it.
-		 * Oddly enough this only happens for INET addresses. */
-		if (ifam->ifam_type == RTM_DELADDR) {
-			struct ifreq ifr;
-			struct sockaddr_in *ifr_sin;
-
-			memset(&ifr, 0, sizeof(ifr));
-			strlcpy(ifr.ifr_name, ifp->name, sizeof(ifr.ifr_name));
-			ifr_sin = (void *)&ifr.ifr_addr;
-			ifr_sin->sin_family = AF_INET;
-			ifr_sin->sin_addr = addr;
-			if (ioctl(ctx->pf_inet_fd, SIOCGIFADDR, &ifr) == 0) {
-				logwarnx("%s: ignored false RTM_DELADDR for %s",
-				    ifp->name, inet_ntoa(addr));
-				break;
+#else
+#warning No SIOCGIFALIAS support
+			/*
+			 * No SIOCGIFALIAS? That sucks!
+			 * This makes this call very heavy weight, but we
+			 * really need to know if the message is late or not.
+			 */
+			struct ifaddrs *ifaddrs = NULL, *ifa;
+			struct in_addr *a;
+
+			getifaddrs(&ifa);
+			for (ifa = ifaddrs; ifa; ifa = ifa->ifa_next) {
+				if (ifa->ifa_addr == NULL ||
+				    ifa->ifa_addr->sa_family != AF_INET)
+					continue;
+				a = (void *)ifa->ifa_addr;
+				if (a->s_addr == addr.s_addr &&
+				    strcmp(ifa->ifa_name, ifp->name) == 0)
+					break;
 			}
-		}
+			freeifaddrs(ifa);
+			if (ifa != NULL)
+				break;
 #endif
+		}
 
 #ifndef HAVE_IFAM_ADDRFLAGS
 		if (ifam->ifam_type == RTM_DELADDR)
@@ -1185,15 +1147,26 @@ if_ifa(struct dhcpcd_ctx *ctx, const struct ifa_msghdr *ifam)
 	{
 		struct in6_addr addr6, mask6;
 		const struct sockaddr_in6 *sin6;
+		int flags;
 
 		sin6 = (const void *)rti_info[RTAX_IFA];
 		addr6 = sin6->sin6_addr;
 		sin6 = (const void *)rti_info[RTAX_NETMASK];
 		mask6 = sin6->sin6_addr;
 
+		/*
+		 * If the address was deleted, lets check if it's
+		 * a late message and it still exists (maybe modified).
+		 * If so, ignore it as deleting an address causes
+		 * dhcpcd to drop any lease to which it belongs.
+		 */
+		if (ifam->ifam_type == RTM_DELADDR) {
+			flags = if_addrflags6(ifp, &addr6, NULL);
+			if (flags != -1)
+				break;
+			addrflags = 0;
+		}
 #ifndef HAVE_IFAM_ADDRFLAGS
-		if (ifam->ifam_type == RTM_DELADDR)
-		    addrflags = 0;
 		else if ((addrflags = if_addrflags6(ifp, &addr6, NULL)) == -1) {
 			if (errno != EADDRNOTAVAIL)
 				logerr("%s: if_addrflags6", __func__);