From 198a1fcc9f6f8c39ddf8c6e962b7e4925d43072c Mon Sep 17 00:00:00 2001
From: Jiri Popelka <jpopelka@redhat.com>
Date: Thu, 24 Oct 2013 10:03:52 +0200
Subject: [PATCH] Fix the socket handling for DHCPv6 clients to allow multiple
instances
of a client on a single machine to work properly. Previously only
one client would receive the packets. Thanks to Jiri Popelka at Red
Hat for the bug report and a potential patch.
[ISC-Bugs #34784]
---
common/discover.c | 19 ++++-----
common/socket.c | 116 ++++++++++++++++++++++++++++++++++++++++++++----------
includes/dhcpd.h | 6 +--
3 files changed, 107 insertions(+), 34 deletions(-)
diff --git a/common/discover.c b/common/discover.c
index a305d92..4027d1a 100644
--- a/common/discover.c
+++ b/common/discover.c
@@ -57,10 +57,6 @@ 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,
@@ -877,7 +873,7 @@ discover_interfaces(int state) {
(state == DISCOVER_RELAY)) {
if_register6(tmp, 1);
} else {
- if_register6(tmp, 0);
+ if_register_linklocal6(tmp);
}
#endif /* DHCPv6 */
}
@@ -933,13 +929,14 @@ 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 8fead01..f0c2c94 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 *)&name;
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
@@ -221,9 +224,9 @@ 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) {
+ if (local_family == AF_INET6 && *do_multicast) {
flag = 1;
if (setsockopt(sock, SOL_SOCKET, SO_REUSEPORT,
(char *)&flag, sizeof(flag)) < 0) {
@@ -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
@@ -747,7 +823,7 @@ 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);
@@ -1046,7 +1122,7 @@ 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 b2fbc8b..56d4eab 100644
--- a/includes/dhcpd.h
+++ b/includes/dhcpd.h
@@ -2378,7 +2378,7 @@ void get_hw_addr(struct interface_info *info);
/* 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)
@@ -2389,7 +2389,7 @@ 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
@@ -2425,6 +2425,7 @@ 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,
@@ -2570,7 +2571,6 @@ 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;
--
1.8.3.1