networkd: networkd: ndisc set SO_BINDTODEVICE on socket (#3294)

From the issue #2004 we are receiving packet even if this
packet is not intended for this interface.

This can be reproduced.

lp3s0: Updating address: 2001:db8:1:0:7e7a:91ff:fe6d:ffe2/64 (valid for 1d)
wlp3s0: Updating address: fe80::7e7a:91ff:fe6d:ffe2/64 (valid forever)
NDisc CLIENT: Received RA from non-link-local address ::. Ignoring.
NDisc CLIENT: Received RA on wrong interface: 2 != 6. Ignoring.
NDisc CLIENT: Received RA on wrong interface: 2 != 3. Ignoring.
enp0s25: Updating address: 2001:db8:1:0:2ad2:44ff:fe6a:ae07/64 (valid for 1d)
enp0s25: Updating address: fe80::2ad2:44ff:fe6a:ae07/64 (valid forever)
NDisc CLIENT: Sent Router Solicitation
NDisc CLIENT: Sent Router Solicitation
NDisc CLIENT: Sent Router Solicitation
NDisc CLIENT: Received RA on wrong interface: 3 != 2. Ignoring.
NDisc CLIENT: Received RA on wrong interface: 3 != 6. Ignoring.
NDisc CLIENT: Received RA from non-link-local address ::. Ignoring.
NDisc CLIENT: Received RA on wrong interface: 2 != 6. Ignoring.
NDisc CLIENT: Received RA on wrong interface: 2 != 3. Ignoring.
enp0s25: Updating address: 2001:db8:1:0:2ad2:44ff:fe6a:ae07/64 (valid for 1d)
enp0s25: Updating address: fe80::2ad2:44ff:fe6a:ae07/64 (valid forever)

Add SO_BINDTODEVICE to socket
fixes #2004

diff --git a/src/libsystemd-network/icmp6-util.c b/src/libsystemd-network/icmp6-util.c
index acad9d7d6a89a7aa442750a1114584e8f212fcc7..d81e9ebd88941365cb8f8ec0c1a49173eda7896d 100644 (file)
--- a/src/libsystemd-network/icmp6-util.c
+++ b/src/libsystemd-network/icmp6-util.c
@@ -26,6 +26,7 @@
 #include <sys/socket.h>
 #include <sys/types.h>
 #include <unistd.h>
+#include <net/if.h>
 #include <linux/if_packet.h>
 
 #include "fd-util.h"
@@ -47,6 +48,7 @@ int icmp6_bind_router_solicitation(int index) {
                 .ipv6mr_interface = index,
         };
         _cleanup_close_ int s = -1;
+        char ifname[IF_NAMESIZE] = "";
         int r, zero = 0, one = 1, hops = 255;
 
         s = socket(AF_INET6, SOCK_RAW | SOCK_CLOEXEC | SOCK_NONBLOCK, IPPROTO_ICMPV6);
@@ -83,6 +85,13 @@ int icmp6_bind_router_solicitation(int index) {
         if (r < 0)
                 return -errno;
 
+        if (if_indextoname(index, ifname) == 0)
+                return -errno;
+
+        r = setsockopt(s, SOL_SOCKET, SO_BINDTODEVICE, ifname, strlen(ifname));
+        if (r < 0)
+                return -errno;
+
         r = s;
         s = -1;
         return r;