libnl3/0003-rh1097176-retry-local-port.patch

From b87aba5b8ddf0475854265fdbf93a02501ab0ffa Mon Sep 17 00:00:00 2001
From: Thomas Graf <tgraf@suug.ch>
Date: Mon, 31 Mar 2014 13:21:06 +0200
Subject: [PATCH 1/5] link: Catch missing io_free() implementations

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: Thomas Haller <thaller@redhat.com>
(cherry picked from commit 34bfce62150d07cf9894f2d9cbd0c989a203ea52)
---
 include/netlink-private/netlink.h | 7 +++++++
 lib/route/link.c                  | 4 ++++
 2 files changed, 11 insertions(+)

diff --git a/include/netlink-private/netlink.h b/include/netlink-private/netlink.h
index 2b1a68e..43ca804 100644
--- a/include/netlink-private/netlink.h
+++ b/include/netlink-private/netlink.h
@@ -102,6 +102,13 @@ struct trans_list {
 		assert(0);						\
 	} while (0)
 
+#define BUG_ON(condition)						\
+	do {								\
+		if (condition)						\
+			BUG();						\
+	} while (0)
+
+
 #define APPBUG(msg)							\
 	do {								\
 		fprintf(stderr, "APPLICATION BUG: %s:%d:%s: %s\n",	\
diff --git a/lib/route/link.c b/lib/route/link.c
index 9979b5b..85790e4 100644
--- a/lib/route/link.c
+++ b/lib/route/link.c
@@ -194,6 +194,10 @@ static void release_link_info(struct rtnl_link *link)
 	if (io != NULL) {
 		if (io->io_free)
 			io->io_free(link);
+		else {
+			/* Catch missing io_free() implementations */
+			BUG_ON(link->l_info);
+		}
 		rtnl_link_info_ops_put(io);
 		link->l_info_ops = NULL;
 	}
-- 
1.9.0


From 88d7ec560f358b23e071acfc41700101de4f673a Mon Sep 17 00:00:00 2001
From: Thomas Haller <thaller@redhat.com>
Date: Wed, 9 Apr 2014 12:08:50 +0200
Subject: [PATCH 2/5] lib/socket: use proper typed constant UINT32_MAX for
 uint32_t typed port

This was a bug on architectures with native int type less then 32 bit.

Acked-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: Thomas Haller <thaller@redhat.com>
(cherry picked from commit 0fd510b3673f479637a6376db3d66dcb9f8911d0)
---
 lib/socket.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/lib/socket.c b/lib/socket.c
index 00d8d6a..959b122 100644
--- a/lib/socket.c
+++ b/lib/socket.c
@@ -82,7 +82,7 @@ static uint32_t generate_local_port(void)
 
 			nl_write_unlock(&port_map_lock);
 
-			return pid + (n << 22);
+			return pid + (((uint32_t)n) << 22);
 		}
 	}
 
@@ -90,14 +90,14 @@ static uint32_t generate_local_port(void)
 
 	/* Out of sockets in our own PID namespace, what to do? FIXME */
 	NL_DBG(1, "Warning: Ran out of unique local port namespace\n");
-	return UINT_MAX;
+	return UINT32_MAX;
 }
 
 static void release_local_port(uint32_t port)
 {
 	int nr;
 
-	if (port == UINT_MAX)
+	if (port == UINT32_MAX)
 		return;
 	
 	nr = port >> 22;
@@ -126,7 +126,7 @@ static struct nl_sock *__alloc_socket(struct nl_cb *cb)
 	sk->s_peer.nl_family = AF_NETLINK;
 	sk->s_seq_expect = sk->s_seq_next = time(0);
 	sk->s_local.nl_pid = generate_local_port();
-	if (sk->s_local.nl_pid == UINT_MAX) {
+	if (sk->s_local.nl_pid == UINT32_MAX) {
 		nl_socket_free(sk);
 		return NULL;
 	}
-- 
1.9.0


From e029e9d1632d7c76338ee366fba097ea2cb6dc8b Mon Sep 17 00:00:00 2001
From: Thomas Haller <thaller@redhat.com>
Date: Wed, 9 Apr 2014 12:08:51 +0200
Subject: [PATCH 3/5] lib/socket: don't fail if no more local ports can be
 assigned in nl_socket_alloc

By failing inside of nl_socket_alloc(), the user can not even work around
when running out of local ports. This patch changes that if there are no more
local ports, we set the port to UINT32_MAX. This is a consistent behavior
to calling nl_socket_set_local_port(sk, 0).

In general, since nl_socket_set_local_port() does not restict the generated
ports in any way we cannot assume to have a valid port. So the check in
the constructor was harmful and users who ever encountered it (because they
created 1024 libnl3 sockets) could not even work around it.

Acked-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: Thomas Haller <thaller@redhat.com>
(cherry picked from commit 0271578987088210d7d2d68addbd5e8fe27d4383)
---
 lib/socket.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/lib/socket.c b/lib/socket.c
index 959b122..eb4a978 100644
--- a/lib/socket.c
+++ b/lib/socket.c
@@ -126,10 +126,6 @@ static struct nl_sock *__alloc_socket(struct nl_cb *cb)
 	sk->s_peer.nl_family = AF_NETLINK;
 	sk->s_seq_expect = sk->s_seq_next = time(0);
 	sk->s_local.nl_pid = generate_local_port();
-	if (sk->s_local.nl_pid == UINT32_MAX) {
-		nl_socket_free(sk);
-		return NULL;
-	}
 
 	return sk;
 }
-- 
1.9.0


From 02c22298f6a5b20ad67a90050fd91ca5b8f358fb Mon Sep 17 00:00:00 2001
From: Thomas Haller <thaller@redhat.com>
Date: Wed, 9 Apr 2014 12:08:52 +0200
Subject: [PATCH 4/5] lib/socket: retry generate local port in nl_connect on
 ADDRINUSE

It can easily happen that the generated local netlink port is alrady in
use. In that case bind will fail with ADDRINUSE.

Users of libnl3 could workaround this, by managing the local ports
themselves, but sometimes these users are libraries too and they also
don't know which ports might be used by other components.

This patch changes that nl_socket_alloc() no longer initilizes the local
port id immediately. Instead it will be initialized when the user calls
nl_socket_get_local_port() the first time and thereby shows interest in
the value.

If bind() fails with ADDRINUSE, check if the user ever cared about the
local port, i.e. whether the local port is still unset. If it is still
unset, assume that libnl should choose a suitable port and retry until
an unused port can be found.

Signed-off-by: Thomas Haller <thaller@redhat.com>
(cherry picked from commit 4dd5fdd0af2c0b7ffe1dbc49313f263dbb2e906f)

Conflicts:
	include/netlink/utils.h
	lib/utils.c
---
 include/Makefile.am              |   1 +
 include/netlink-private/socket.h |  31 +++++++++++
 include/netlink/utils.h          |   9 ++++
 lib/nl.c                         |  62 +++++++++++++++++++---
 lib/socket.c                     | 110 +++++++++++++++++++++++++++++++--------
 lib/utils.c                      |   9 ++++
 libnl.sym.in                     |   5 ++
 7 files changed, 199 insertions(+), 28 deletions(-)
 create mode 100644 include/netlink-private/socket.h

diff --git a/include/Makefile.am b/include/Makefile.am
index 32f872f..ac5ce65 100644
--- a/include/Makefile.am
+++ b/include/Makefile.am
@@ -138,6 +138,7 @@ noinst_HEADERS = \
 	linux/tc_ematch/tc_em_meta.h \
 	netlink-private/genl.h \
 	netlink-private/netlink.h \
+	netlink-private/socket.h \
 	netlink-private/tc.h \
 	netlink-private/types.h \
 	netlink-private/cache-api.h \
diff --git a/include/netlink-private/socket.h b/include/netlink-private/socket.h
new file mode 100644
index 0000000..86a440c
--- /dev/null
+++ b/include/netlink-private/socket.h
@@ -0,0 +1,31 @@
+/*
+ * netlink-private/socket.h		Private declarations for socket
+ *
+ *	This library is free software; you can redistribute it and/or
+ *	modify it under the terms of the GNU Lesser General Public
+ *	License as published by the Free Software Foundation version 2.1
+ *	of the License.
+ *
+ * Copyright (c) 2014 Thomas Graf <tgraf@suug.ch>
+ */
+
+#ifndef NETLINK_SOCKET_PRIV_H_
+#define NETLINK_SOCKET_PRIV_H_
+
+#include <netlink-private/netlink.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+int _nl_socket_is_local_port_unspecified (struct nl_sock *sk);
+uint32_t _nl_socket_generate_local_port_no_release(struct nl_sock *sk);
+
+void _nl_socket_used_ports_release_all(const uint32_t *used_ports);
+void _nl_socket_used_ports_set(uint32_t *used_ports, uint32_t port);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/include/netlink/utils.h b/include/netlink/utils.h
index da46a55..e929cfd 100644
--- a/include/netlink/utils.h
+++ b/include/netlink/utils.h
@@ -82,6 +82,15 @@ extern void	nl_dump_line(struct nl_dump_params *, const char *, ...);
 enum {
 	NL_CAPABILITY_NONE,
 
+	/**
+	 * Indicate that the local port is unspecified until the user accesses
+	 * it (via nl_socket_get_local_port()) or until nl_connect(). More importantly,
+	 * if the port is left unspecified, nl_connect() will retry generating another
+	 * port when bind() fails with ADDRINUSE.
+	 */
+	NL_CAPABILITY_NL_CONNECT_RETRY_GENERATE_PORT_ON_ADDRINUSE = 4,
+#define NL_CAPABILITY_NL_CONNECT_RETRY_GENERATE_PORT_ON_ADDRINUSE NL_CAPABILITY_NL_CONNECT_RETRY_GENERATE_PORT_ON_ADDRINUSE
+
 	__NL_CAPABILITY_MAX
 #define NL_CAPABILITY_MAX                               (__NL_CAPABILITY_MAX - 1)
 };
diff --git a/lib/nl.c b/lib/nl.c
index 4692490..25fd59c 100644
--- a/lib/nl.c
+++ b/lib/nl.c
@@ -26,6 +26,7 @@
  */
 
 #include <netlink-private/netlink.h>
+#include <netlink-private/socket.h>
 #include <netlink/netlink.h>
 #include <netlink/utils.h>
 #include <netlink/handlers.h>
@@ -75,6 +76,16 @@
  *       be closed automatically if any of the `exec` family functions succeed.
  *       This is essential for multi threaded programs.
  *
+ * @note The local port (`nl_socket_get_local_port()`) is unspecified after
+ *       creating a new socket. It only gets determined when accessing the
+ *       port the first time or during `nl_connect()`. When nl_connect()
+ *       fails during `bind()` due to `ADDRINUSE`, it will retry with
+ *       different ports if the port is unspecified. Unless you want to enforce
+ *       the use of a specific local port, don't access the local port (or
+ *       reset it to `unspecified` by calling `nl_socket_set_local_port(sk, 0)`).
+ *       This capability is indicated by
+ *       `%NL_CAPABILITY_NL_CONNECT_RETRY_GENERATE_PORT_ON_ADDRINUSE`.
+ *
  * @see nl_socket_alloc()
  * @see nl_close()
  *
@@ -85,6 +96,7 @@
 int nl_connect(struct nl_sock *sk, int protocol)
 {
 	int err, flags = 0;
+	int errsv;
 	socklen_t addrlen;
 
 #ifdef SOCK_CLOEXEC
@@ -96,7 +108,9 @@ int nl_connect(struct nl_sock *sk, int protocol)
 
 	sk->s_fd = socket(AF_NETLINK, SOCK_RAW | flags, protocol);
 	if (sk->s_fd < 0) {
-		err = -nl_syserr2nlerr(errno);
+		errsv = errno;
+		NL_DBG(4, "nl_connect(%p): socket() failed with %d\n", sk, errsv);
+		err = -nl_syserr2nlerr(errsv);
 		goto errout;
 	}
 
@@ -106,11 +120,45 @@ int nl_connect(struct nl_sock *sk, int protocol)
 			goto errout;
 	}
 
-	err = bind(sk->s_fd, (struct sockaddr*) &sk->s_local,
-		   sizeof(sk->s_local));
-	if (err < 0) {
-		err = -nl_syserr2nlerr(errno);
-		goto errout;
+	if (_nl_socket_is_local_port_unspecified (sk)) {
+		uint32_t port;
+		uint32_t used_ports[32] = { 0 };
+
+		while (1) {
+			port = _nl_socket_generate_local_port_no_release(sk);
+
+			if (port == UINT32_MAX) {
+				NL_DBG(4, "nl_connect(%p): no more unused local ports.\n", sk);
+				_nl_socket_used_ports_release_all(used_ports);
+				err = -NLE_EXIST;
+				goto errout;
+			}
+			err = bind(sk->s_fd, (struct sockaddr*) &sk->s_local,
+				   sizeof(sk->s_local));
+			if (err == 0)
+				break;
+
+			errsv = errno;
+			if (errsv == EADDRINUSE) {
+				NL_DBG(4, "nl_connect(%p): local port %u already in use. Retry.\n", sk, (unsigned) port);
+				_nl_socket_used_ports_set(used_ports, port);
+			} else {
+				NL_DBG(4, "nl_connect(%p): bind() for port %u failed with %d\n", sk, (unsigned) port, errsv);
+				_nl_socket_used_ports_release_all(used_ports);
+				err = -nl_syserr2nlerr(errsv);
+				goto errout;
+			}
+		}
+		_nl_socket_used_ports_release_all(used_ports);
+	} else {
+		err = bind(sk->s_fd, (struct sockaddr*) &sk->s_local,
+			   sizeof(sk->s_local));
+		if (err != 0) {
+			errsv = errno;
+			NL_DBG(4, "nl_connect(%p): bind() failed with %d\n", sk, errsv);
+			err = -nl_syserr2nlerr(errsv);
+			goto errout;
+		}
 	}
 
 	addrlen = sizeof(sk->s_local);
@@ -405,7 +453,7 @@ void nl_complete_msg(struct nl_sock *sk, struct nl_msg *msg)
 
 	nlh = nlmsg_hdr(msg);
 	if (nlh->nlmsg_pid == NL_AUTO_PORT)
-		nlh->nlmsg_pid = sk->s_local.nl_pid;
+		nlh->nlmsg_pid = nl_socket_get_local_port(sk);
 
 	if (nlh->nlmsg_seq == NL_AUTO_SEQ)
 		nlh->nlmsg_seq = sk->s_seq_next++;
diff --git a/lib/socket.c b/lib/socket.c
index eb4a978..c08f053 100644
--- a/lib/socket.c
+++ b/lib/socket.c
@@ -30,6 +30,7 @@
 #include "defs.h"
 
 #include <netlink-private/netlink.h>
+#include <netlink-private/socket.h>
 #include <netlink/netlink.h>
 #include <netlink/utils.h>
 #include <netlink/handlers.h>
@@ -96,17 +97,59 @@ static uint32_t generate_local_port(void)
 static void release_local_port(uint32_t port)
 {
 	int nr;
+	uint32_t mask;
 
 	if (port == UINT32_MAX)
 		return;
-	
+
+	BUG_ON(port == 0);
+
 	nr = port >> 22;
+	mask = 1UL << (nr % 32);
+	nr /= 32;
 
 	nl_write_lock(&port_map_lock);
-	used_ports_map[nr / 32] &= ~(1 << (nr % 32));
+	BUG_ON((used_ports_map[nr] & mask) != mask);
+	used_ports_map[nr] &= ~mask;
 	nl_write_unlock(&port_map_lock);
 }
 
+/** \cond skip */
+void _nl_socket_used_ports_release_all(const uint32_t *used_ports)
+{
+	int i;
+
+	for (i = 0; i < 32; i++) {
+		if (used_ports[i] != 0) {
+			nl_write_lock(&port_map_lock);
+			for (; i < 32; i++) {
+				BUG_ON((used_ports_map[i] & used_ports[i]) != used_ports[i]);
+				used_ports_map[i] &= ~(used_ports[i]);
+			}
+			nl_write_unlock(&port_map_lock);
+			return;
+		}
+	}
+}
+
+void _nl_socket_used_ports_set(uint32_t *used_ports, uint32_t port)
+{
+	int nr;
+	int32_t mask;
+
+	nr = port >> 22;
+	mask = 1UL << (nr % 32);
+	nr /= 32;
+
+	/*
+	BUG_ON(port == UINT32_MAX || port == 0 || (getpid() & 0x3FFFFF) != (port & 0x3FFFFF));
+	BUG_ON(used_ports[nr] & mask);
+	*/
+
+	used_ports[nr] |= mask;
+}
+/** \endcond */
+
 /**
  * @name Allocation
  * @{
@@ -125,7 +168,9 @@ static struct nl_sock *__alloc_socket(struct nl_cb *cb)
 	sk->s_local.nl_family = AF_NETLINK;
 	sk->s_peer.nl_family = AF_NETLINK;
 	sk->s_seq_expect = sk->s_seq_next = time(0);
-	sk->s_local.nl_pid = generate_local_port();
+
+	/* the port is 0 (unspecified), meaning NL_OWN_PORT */
+	sk->s_flags = NL_OWN_PORT;
 
 	return sk;
 }
@@ -261,6 +306,26 @@ void nl_socket_enable_auto_ack(struct nl_sock *sk)
 
 /** @} */
 
+/** \cond skip */
+int _nl_socket_is_local_port_unspecified(struct nl_sock *sk)
+{
+	return (sk->s_local.nl_pid == 0);
+}
+
+uint32_t _nl_socket_generate_local_port_no_release(struct nl_sock *sk)
+{
+	uint32_t port;
+
+	/* reset the port to generate_local_port(), but do not release
+	 * the previously generated port. */
+
+	port = generate_local_port();
+	sk->s_flags &= ~NL_OWN_PORT;
+	sk->s_local.nl_pid = port;
+	return port;
+}
+/** \endcond */
+
 /**
  * @name Source Idenficiation
  * @{
@@ -268,6 +333,18 @@ void nl_socket_enable_auto_ack(struct nl_sock *sk)
 
 uint32_t nl_socket_get_local_port(const struct nl_sock *sk)
 {
+	if (sk->s_local.nl_pid == 0) {
+		/* modify the const argument sk. This is justified, because
+		 * nobody ever saw the local_port from externally. So, we
+		 * initilize it on first use.
+		 *
+		 * Note that this also means that you cannot call this function
+		 * from multiple threads without synchronization. But nl_sock
+		 * is not automatically threadsafe anyway, so the user is not
+		 * allowed to do that.
+		 */
+		return _nl_socket_generate_local_port_no_release((struct nl_sock *) sk);
+	}
 	return sk->s_local.nl_pid;
 }
 
@@ -276,27 +353,18 @@ uint32_t nl_socket_get_local_port(const struct nl_sock *sk)
  * @arg sk		Netlink socket.
  * @arg port		Local port identifier
  *
- * Assigns a local port identifier to the socket. If port is 0
- * a unique port identifier will be generated automatically.
+ * Assigns a local port identifier to the socket.
+ *
+ * If port is 0, the port is reset to 'unspecified' as it is after newly
+ * calling nl_socket_alloc().
+ * Unspecified means, that the port will be generated automatically later
+ * on first use (either on nl_socket_get_local_port() or nl_connect()).
  */
 void nl_socket_set_local_port(struct nl_sock *sk, uint32_t port)
 {
-	if (port == 0) {
-		port = generate_local_port(); 
-		/*
-		 * Release local port after generation of a new one to be
-		 * able to change local port using nl_socket_set_local_port(, 0)
-		 */
-		if (!(sk->s_flags & NL_OWN_PORT))
-			release_local_port(sk->s_local.nl_pid);
-		else
-			sk->s_flags &= ~NL_OWN_PORT;
-	} else  {
-		if (!(sk->s_flags & NL_OWN_PORT))
-			release_local_port(sk->s_local.nl_pid);
-		sk->s_flags |= NL_OWN_PORT;
-	}
-
+	if (!(sk->s_flags & NL_OWN_PORT))
+		release_local_port(sk->s_local.nl_pid);
+	sk->s_flags |= NL_OWN_PORT;
 	sk->s_local.nl_pid = port;
 }
 
diff --git a/lib/utils.c b/lib/utils.c
index 18bd950..275138d 100644
--- a/lib/utils.c
+++ b/lib/utils.c
@@ -1143,6 +1143,15 @@ int nl_has_capability (int capability)
 			_NL_SETV((i), 1, (v1)) | _NL_SETV((i), 5, (v5)) | \
 			_NL_SETV((i), 2, (v2)) | _NL_SETV((i), 6, (v6)) | \
 			_NL_SETV((i), 3, (v3)) | _NL_SETV((i), 7, (v7)) )
+		_NL_SET(0,
+			0,
+			0,
+			0,
+			NL_CAPABILITY_NL_CONNECT_RETRY_GENERATE_PORT_ON_ADDRINUSE,
+			0,
+			0,
+			0,
+			0),
 #undef _NL_SET
 #undef _NL_SETV
 #undef _NL_ASSERT
diff --git a/libnl.sym.in b/libnl.sym.in
index e8f6c53..df8888c 100644
--- a/libnl.sym.in
+++ b/libnl.sym.in
@@ -1,4 +1,9 @@
 libnl_@MAJ_VERSION@ {
 global:
 	*;
+local:
+	_nl_socket_generate_local_port_no_release;
+	_nl_socket_is_local_port_unspecified;
+	_nl_socket_used_ports_release_all;
+	_nl_socket_used_ports_set;
 };
-- 
1.9.0


From 04f64c10aea96c97dea0327c6a2ac80b1da63c7c Mon Sep 17 00:00:00 2001
From: Thomas Haller <thaller@redhat.com>
Date: Wed, 9 Apr 2014 12:08:53 +0200
Subject: [PATCH 5/5] lib/socket: randomize the generated local port

Instead of always trying the same order of ports when
looking for an unused port, randomize the order (naively).

As libnl-1 uses the same function, it is likely that two applications
that are using both libraries generate the same ports. By chosing a
different order how to select the local port, the chances are smaller
for this to happen (however, it cannot avoid it entirely. The user
and/or libnl3 still has to cope with the situation, that somebody
else might already use the port).

Signed-off-by: Thomas Haller <thaller@redhat.com>
(cherry picked from commit 1f734a8f892abcd3f81637df4a089155aca1b66a)
---
 lib/socket.c | 29 ++++++++++++++++++++++++++---
 1 file changed, 26 insertions(+), 3 deletions(-)

diff --git a/lib/socket.c b/lib/socket.c
index c08f053..5f61b38 100644
--- a/lib/socket.c
+++ b/lib/socket.c
@@ -62,16 +62,39 @@ static NL_RW_LOCK(port_map_lock);
 
 static uint32_t generate_local_port(void)
 {
-	int i, n;
+	int i, j, n, m;
+	static uint16_t idx_state = 0;
 	uint32_t pid = getpid() & 0x3FFFFF;
 
 	nl_write_lock(&port_map_lock);
 
-	for (i = 0; i < 32; i++) {
+	if (idx_state == 0) {
+		uint32_t t = time(NULL);
+
+		/* from time to time (on average each 2^15 calls), the idx_state will
+		 * be zero again. No problem, just "seed" anew with time(). */
+		idx_state = t ^ (t >> 16) ^ 0x3047;
+	} else
+		idx_state = idx_state + 20011; /* add prime number */
+
+	i = idx_state >> 5;
+	n = idx_state;
+	for (j = 0; j < 32; j++) {
+		/* walk the index somewhat randomized, with always leaving the block
+		 * #0 as last. The reason is that libnl-1 will start at block #0,
+		 * so just leave the first 32 ports preferably for libnl-1 owned sockets
+		 * (this is relevant only if the applications ends up using both versions
+		 * of the library and doesn't hurt otherwise). */
+		if (j == 31)
+			i = 0;
+		else
+			i = (((i-1) + 7) % 31) + 1;
+
 		if (used_ports_map[i] == 0xFFFFFFFF)
 			continue;
 
-		for (n = 0; n < 32; n++) {
+		for (m = 0; m < 32; m++) {
+			n = (n + 13) % 32;
 			if (1UL & (used_ports_map[i] >> n))
 				continue;
 
-- 
1.9.0