From 429b43502675550ed61d3f62a4ffd295ab10732d Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Thu, 6 Oct 2016 15:48:15 +0200 Subject: 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. --- src/basic/socket-util.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) (limited to 'src/basic/socket-util.c') 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; +} -- cgit v1.2.1