From 4b8251a0c06b7d8706a28904fdef2414f045cc2c Mon Sep 17 00:00:00 2001

From: Shawn Routhier <sar@isc.org>

Date: Mon, 21 Oct 2013 14:59:41 -0700

Subject: [PATCH] -n [master] Fix the socket handling for DHCPv6 clients to

 allow multiple instances of a clinet on a single machine to work properly.

 [ISC-Bugs #34784]

---

 common/discover.c |  19 ++++-----

 common/socket.c   | 114 +++++++++++++++++++++++++++++++++++++++++++++---------

 includes/dhcpd.h  |   6 +--

 4 files changed, 112 insertions(+), 33 deletions(-)

diff --git a/common/discover.c b/common/discover.c

index 1d55317..30da566 100644

--- a/common/discover.c

+++ b/common/discover.c

@@ -58,10 +58,6 @@ struct in_addr limited_broadcast;

 int local_family = AF_INET;

 struct in_addr local_address;

-#ifdef DHCPv6

-struct in6_addr local_address6;

-#endif /* DHCPv6 */

-

 void (*bootp_packet_handler) (struct interface_info *,

 			      struct dhcp_packet *, unsigned,

 			      unsigned int,

@@ -1242,7 +1238,7 @@ discover_interfaces(int state) {

 			    (state == DISCOVER_RELAY)) {

 				if_register6(tmp, 1);

 			} else {

-				if_register6(tmp, 0);

+				if_register_linklocal6(tmp);

 			}

 #endif /* DHCPv6 */

 		}

@@ -1298,13 +1294,14 @@ discover_interfaces(int state) {

 				   tmp -> name, isc_result_totext (status));

 #if defined(DHCPv6)

-		/* Only register the first interface for V6, since they all

-		 * use the same socket.  XXX: This has some messy side

-		 * effects if we start dynamically adding and removing

-		 * interfaces, but we're well beyond that point in terms of

-		 * mess.

+		/* Only register the first interface for V6, since

+		 * servers and relays all use the same socket.

+		 * XXX: This has some messy side effects if we start

+		 * dynamically adding and removing interfaces, but

+		 * we're well beyond that point in terms of mess.

 		 */

-		if (local_family == AF_INET6)

+		if (((state == DISCOVER_SERVER) || (state == DISCOVER_RELAY)) &&

+		    (local_family == AF_INET6))

 			break;

 #endif

 	} /* for (tmp = interfaces; ... */

diff --git a/common/socket.c b/common/socket.c

index 8a9ebea..2bedd3a 100644

--- a/common/socket.c

+++ b/common/socket.c

@@ -67,6 +67,7 @@

  * XXX: this is gross.  we need to go back and overhaul the API for socket

  * handling.

  */

+static int no_global_v6_socket = 0;

 static unsigned int global_v6_socket_references = 0;

 static int global_v6_socket = -1;

@@ -127,7 +128,7 @@ void if_reinitialize_receive (info)

 /* Generic interface registration routine... */

 int

 if_register_socket(struct interface_info *info, int family,

-		   int *do_multicast)

+		   int *do_multicast, struct in6_addr *linklocal6)

 {

 	struct sockaddr_storage name;

 	int name_len;

@@ -161,10 +162,12 @@ if_register_socket(struct interface_info *info, int family,

 		addr6 = (struct sockaddr_in6 *)&nam;; 

 		addr6->sin6_family = AF_INET6;

 		addr6->sin6_port = local_port;

-		/* XXX: What will happen to multicasts if this is nonzero? */

-		memcpy(&addr6->sin6_addr,

-		       &local_address6, 

-		       sizeof(addr6->sin6_addr));

+		if (linklocal6) {

+			memcpy(&addr6->sin6_addr,

+			       linklocal6,

+			       sizeof(addr6->sin6_addr));

+			addr6->sin6_scope_id = if_nametoindex(info->name);

+		}

 #ifdef HAVE_SA_LEN

 		addr6->sin6_len = sizeof(*addr6);

 #endif

@@ -221,7 +224,7 @@ if_register_socket(struct interface_info *info, int family,

 	 * daemons can bind to their own sockets and get data for their

 	 * respective interfaces.  This does not (and should not) affect

 	 * DHCPv4 sockets; we can't yet support BSD sockets well, much

-	 * less multiple sockets.

+	 * less multiple sockets. Make sense only with multicast.

 	 */

 	if (local_family == AF_INET6) {

 		flag = 1;

@@ -322,7 +325,7 @@ void if_register_send (info)

 	struct interface_info *info;

 {

 #ifndef USE_SOCKET_RECEIVE

-	info->wfdesc = if_register_socket(info, AF_INET, 0);

+	info->wfdesc = if_register_socket(info, AF_INET, 0, NULL);

 	/* If this is a normal IPv4 address, get the hardware address. */

 	if (strcmp(info->name, "fallback") != 0)

 		get_hw_addr(info);

@@ -368,7 +371,7 @@ void if_register_receive (info)

 #if defined(IP_PKTINFO) && defined(IP_RECVPKTINFO) && defined(USE_V4_PKTINFO)

 	if (global_v4_socket_references == 0) {

-		global_v4_socket = if_register_socket(info, AF_INET, 0);

+		global_v4_socket = if_register_socket(info, AF_INET, 0, NULL);

 		if (global_v4_socket < 0) {

 			/*

 			 * if_register_socket() fatally logs if it fails to

@@ -384,7 +387,7 @@ void if_register_receive (info)

 #else

 	/* If we're using the socket API for sending and receiving,

 	   we don't need to register this interface twice. */

-	info->rfdesc = if_register_socket(info, AF_INET, 0);

+	info->rfdesc = if_register_socket(info, AF_INET, 0, NULL);

 #endif /* IP_PKTINFO... */

 	/* If this is a normal IPv4 address, get the hardware address. */

 	if (strcmp(info->name, "fallback") != 0)

@@ -477,9 +480,13 @@ if_register6(struct interface_info *info, int do_multicast) {

 	/* Bounce do_multicast to a stack variable because we may change it. */

 	int req_multi = do_multicast;

+	if (no_global_v6_socket) {

+		log_fatal("Impossible condition at %s:%d", MDL);

+	}

+

 	if (global_v6_socket_references == 0) {

 		global_v6_socket = if_register_socket(info, AF_INET6,

-						      &req_multi);

+						      &req_multi, NULL);

 		if (global_v6_socket < 0) {

 			/*

 			 * if_register_socket() fatally logs if it fails to

@@ -515,12 +522,73 @@ if_register6(struct interface_info *info, int do_multicast) {

 	}

 }

+/*

+ * Register an IPv6 socket bound to the link-local address of

+ * the argument interface (used by clients on a multiple interface box,

+ * vs. a server or a relay using the global IPv6 socket and running

+ * *only* in a single instance).

+ */

+void

+if_register_linklocal6(struct interface_info *info) {

+	int sock;

+	int count;

+	struct in6_addr *addr6 = NULL;

+	int req_multi = 0;

+

+	if (global_v6_socket >= 0) {

+		log_fatal("Impossible condition at %s:%d", MDL);

+	}

+		

+	no_global_v6_socket = 1;

+

+	/* get the (?) link-local address */

+	for (count = 0; count < info->v6address_count; count++) {

+		addr6 = &info->v6addresses[count];

+		if (IN6_IS_ADDR_LINKLOCAL(addr6))

+			break;

+	}

+

+	if (!addr6) {

+		log_fatal("no link-local IPv6 address for %s", info->name);

+	}

+

+	sock = if_register_socket(info, AF_INET6, &req_multi, addr6);

+

+	if (sock < 0) {

+		log_fatal("if_register_socket for %s fails", info->name);

+	}

+

+	info->rfdesc = sock;

+	info->wfdesc = sock;

+

+	get_hw_addr(info);

+

+	if (!quiet_interface_discovery) {

+		if (info->shared_network != NULL) {

+			log_info("Listening on Socket/%d/%s/%s",

+				 global_v6_socket, info->name, 

+				 info->shared_network->name);

+			log_info("Sending on   Socket/%d/%s/%s",

+				 global_v6_socket, info->name,

+				 info->shared_network->name);

+		} else {

+			log_info("Listening on Socket/%s", info->name);

+			log_info("Sending on   Socket/%s", info->name);

+		}

+	}

+}

+

 void 

 if_deregister6(struct interface_info *info) {

-	/* Dereference the global v6 socket. */

-	if ((info->rfdesc == global_v6_socket) &&

-	    (info->wfdesc == global_v6_socket) &&

-	    (global_v6_socket_references > 0)) {

+	/* client case */

+	if (no_global_v6_socket) {

+		close(info->rfdesc);

+		info->rfdesc = -1;

+		info->wfdesc = -1;

+	} else if ((info->rfdesc == global_v6_socket) &&

+		   (info->wfdesc == global_v6_socket) &&

+		   (global_v6_socket_references > 0)) {

+		/* Dereference the global v6 socket. */

 		global_v6_socket_references--;

 		info->rfdesc = -1;

 		info->wfdesc = -1;

@@ -540,7 +608,8 @@ if_deregister6(struct interface_info *info) {

 		}

 	}

-	if (global_v6_socket_references == 0) {

+	if (!no_global_v6_socket &&

+	    (global_v6_socket_references == 0)) {

 		close(global_v6_socket);

 		global_v6_socket = -1;

@@ -692,9 +761,11 @@ ssize_t send_packet6(struct interface_info *interface,

 		     struct sockaddr_in6 *to) {

 	struct msghdr m;

 	struct iovec v;

+	struct sockaddr_in6 dst;

 	int result;

 	struct in6_pktinfo *pktinfo;

 	struct cmsghdr *cmsg;

+	unsigned int ifindex;

 	/*

 	 * If necessary allocate space for the control message header.

@@ -717,9 +788,14 @@ ssize_t send_packet6(struct interface_info *interface,

 	/*

 	 * Set the target address we're sending to.

+	 * Enforce the scope ID for bogus BSDs.

 	 */

-	m.msg_name = to;

-	m.msg_namelen = sizeof(*to);

+	memcpy(&dst, to, sizeof(dst));

+	m.msg_name = &dst;

+	m.msg_namelen = sizeof(dst);

+	ifindex = if_nametoindex(interface->name);

+	if (no_global_v6_socket)

+		dst.sin6_scope_id = ifindex;

 	/*

 	 * Set the data buffer we're sending. (Using this wacky 

@@ -748,7 +824,7 @@ ssize_t send_packet6(struct interface_info *interface,

 	cmsg->cmsg_len = CMSG_LEN(sizeof(*pktinfo));

 	pktinfo = (struct in6_pktinfo *)CMSG_DATA(cmsg);

 	memset(pktinfo, 0, sizeof(*pktinfo));

-	pktinfo->ipi6_ifindex = if_nametoindex(interface->name);

+	pktinfo->ipi6_ifindex = ifindex;

 	m.msg_controllen = cmsg->cmsg_len;

 	result = sendmsg(interface->wfdesc, &m, 0);

@@ -1047,7 +1123,7 @@ void maybe_setup_fallback ()

 	isc_result_t status;

 	struct interface_info *fbi = (struct interface_info *)0;

 	if (setup_fallback (&fbi, MDL)) {

-		fbi -> wfdesc = if_register_socket (fbi, AF_INET, 0);

+		fbi -> wfdesc = if_register_socket (fbi, AF_INET, 0, NULL);

 		fbi -> rfdesc = fbi -> wfdesc;

 		log_info ("Sending on   Socket/%s%s%s",

 		      fbi -> name,

diff --git a/includes/dhcpd.h b/includes/dhcpd.h

index 73c632f..9e18818 100644

--- a/includes/dhcpd.h

+++ b/includes/dhcpd.h

@@ -2414,7 +2414,7 @@ void get_hw_addr(const char *name, struct hardware *hw);

 /* socket.c */

 #if defined (USE_SOCKET_SEND) || defined (USE_SOCKET_RECEIVE) \

 	|| defined (USE_SOCKET_FALLBACK)

-int if_register_socket(struct interface_info *, int, int *);

+int if_register_socket(struct interface_info *, int, int *, struct in6_addr *);

 #endif

 #if defined (USE_SOCKET_FALLBACK) && !defined (USE_SOCKET_SEND)

@@ -2425,7 +2425,7 @@ ssize_t send_fallback (struct interface_info *,

 		       struct in_addr,

 		       struct sockaddr_in *, struct hardware *);

 ssize_t send_fallback6(struct interface_info *, struct packet *,

-		       struct dhcp_packet *, size_t, struct in6_addr,

+		       struct dhcp_packet *, size_t, struct in6_addr *,

 		       struct sockaddr_in6 *, struct hardware *);

 #endif

@@ -2461,6 +2461,7 @@ void maybe_setup_fallback (void);

 #endif

 void if_register6(struct interface_info *info, int do_multicast);

+void if_register_linklocal6(struct interface_info *info);

 ssize_t receive_packet6(struct interface_info *interface,

 			unsigned char *buf, size_t len,

 			struct sockaddr_in6 *from, struct in6_addr *to_addr,

@@ -2606,7 +2607,6 @@ void interface_trace_setup (void);

 extern struct in_addr limited_broadcast;

 extern int local_family;

 extern struct in_addr local_address;

-extern struct in6_addr local_address6;

 extern u_int16_t local_port;

 extern u_int16_t remote_port;

-- 

2.1.0