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authorLennart Poettering <lennart@poettering.net>2016-10-06 15:48:15 +0200
committerLennart Poettering <lennart@poettering.net>2016-10-06 19:04:01 +0200
commit429b43502675550ed61d3f62a4ffd295ab10732d (patch)
treebbbe9e1f7f9573bf14b6508a31c27a1307d59f7c /src/basic/socket-util.c
parentd21494ea25a5f36af998191a7d86adc2fe511638 (diff)
sd-device/networkd: unify code to get a socket for issuing netdev ioctls on
As suggested here: https://github.com/systemd/systemd/pull/4296#issuecomment-251911349 Let's try AF_INET first as socket, but let's fall back to AF_NETLINK, so that we can use a protocol-independent socket here if possible. This has the benefit that our code will still work even if AF_INET/AF_INET6 is made unavailable (for exmple via seccomp), at least on current kernels.
Diffstat (limited to 'src/basic/socket-util.c')
-rw-r--r--src/basic/socket-util.c17
1 files changed, 17 insertions, 0 deletions
diff --git a/src/basic/socket-util.c b/src/basic/socket-util.c
index 5c829e0e7e..1662c04705 100644
--- a/src/basic/socket-util.c
+++ b/src/basic/socket-util.c
@@ -1060,3 +1060,20 @@ struct cmsghdr* cmsg_find(struct msghdr *mh, int level, int type, socklen_t leng
return NULL;
}
+
+int socket_ioctl_fd(void) {
+ int fd;
+
+ /* Create a socket to invoke the various network interface ioctl()s on. Traditionally only AF_INET was good for
+ * that. Since kernel 4.6 AF_NETLINK works for this too. We first try to use AF_INET hence, but if that's not
+ * available (for example, because it is made unavailable via SECCOMP or such), we'll fall back to the more
+ * generic AF_NETLINK. */
+
+ fd = socket(AF_INET, SOCK_DGRAM|SOCK_CLOEXEC, 0);
+ if (fd < 0)
+ fd = socket(AF_NETLINK, SOCK_RAW|SOCK_CLOEXEC, NETLINK_GENERIC);
+ if (fd < 0)
+ return -errno;
+
+ return fd;
+}