const struct nlmsghdr *nlmsg;
nlmsg = buf->data;
- rtm = (const struct rtmsg *) ((const char *) buf->data + NLMSG_HDRLEN);
+ rtm = ofpbuf_at(buf, NLMSG_HDRLEN, sizeof *rtm);
if (rtm->rtm_family != AF_INET) {
VLOG_DBG_RL(&rl, "received non AF_INET rtnetlink route message");