[PATCH 1/8] libbb: set netlink socket revbuf size before binding

Jan Klötzke jan at kloetzke.net
Mon Dec 16 21:56:49 UTC 2019


As soon as the socket is bound it will receive messages. Make sure the
recieve buffer size is increased before the first message is received.

Signed-off-by: Jan Klötzke <jan at kloetzke.net>
---
 libbb/xconnect.c | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/libbb/xconnect.c b/libbb/xconnect.c
index e9a2470e4..5b32599ca 100644
--- a/libbb/xconnect.c
+++ b/libbb/xconnect.c
@@ -422,14 +422,10 @@ int FAST_FUNC create_and_bind_to_netlink(int proto, int grp, unsigned rcvbuf)
 	struct sockaddr_nl sa;
 	int fd;
 
-	memset(&sa, 0, sizeof(sa));
-	sa.nl_family = AF_NETLINK;
-	sa.nl_pid = getpid();
-	sa.nl_groups = grp;
 	fd = xsocket(AF_NETLINK, SOCK_DGRAM, proto);
-	xbind(fd, (struct sockaddr *) &sa, sizeof(sa));
-	close_on_exec_on(fd);
 
+	// Set receive buffer size before binding the socket. We want to have
+	// enough space before we start receiving messages.
 	if (rcvbuf != 0) {
 		// SO_RCVBUFFORCE (root only) can go above net.core.rmem_max sysctl
 		setsockopt_SOL_SOCKET_int(fd, SO_RCVBUF,      rcvbuf);
@@ -444,6 +440,13 @@ int FAST_FUNC create_and_bind_to_netlink(int proto, int grp, unsigned rcvbuf)
 # endif
 	}
 
+	memset(&sa, 0, sizeof(sa));
+	sa.nl_family = AF_NETLINK;
+	sa.nl_pid = getpid();
+	sa.nl_groups = grp;
+	xbind(fd, (struct sockaddr *) &sa, sizeof(sa));
+	close_on_exec_on(fd);
+
 	return fd;
 }
 #endif
-- 
2.20.1



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