ndp: answer global-addressed NS manually

[project/odhcpd.git] / src / netlink.c

diff --git a/src/netlink.c b/src/netlink.c
index d9c2b404d47d9d8029e1720a01949ce99783404e..e3b2c3f0931c9c82a44cc32234024f492f2e6239 100644 (file)
--- a/src/netlink.c
+++ b/src/netlink.c
@@ -684,6 +684,113 @@ out:
 }
 
 
+struct neigh_info {
+       int ifindex;
+       int pending;
+       const struct in6_addr *addr;
+       int ret;
+};
+
+
+static int cb_valid_handler2(struct nl_msg *msg, void *arg)
+{
+       struct neigh_info *ctxt = (struct neigh_info *)arg;
+       struct nlmsghdr *hdr = nlmsg_hdr(msg);
+       struct ndmsg *ndm;
+       struct nlattr *nla_dst;
+
+       if (hdr->nlmsg_type != RTM_NEWNEIGH)
+               return NL_SKIP;
+
+       ndm = NLMSG_DATA(hdr);
+       if (ndm->ndm_family != AF_INET6 ||
+                       (ctxt->ifindex && ndm->ndm_ifindex != ctxt->ifindex))
+               return NL_SKIP;
+
+       if (!(ndm->ndm_flags & NTF_PROXY))
+               return NL_SKIP;
+
+       nla_dst = nlmsg_find_attr(hdr, sizeof(*ndm), NDA_DST);
+       if (!nla_dst)
+               return NL_SKIP;
+
+       if (nla_memcmp(nla_dst,ctxt->addr, 16) == 0)
+               ctxt->ret = 1;
+
+       return NL_OK;
+}
+
+
+static int cb_finish_handler2(_unused struct nl_msg *msg, void *arg)
+{
+       struct neigh_info *ctxt = (struct neigh_info *)arg;
+
+       ctxt->pending = 0;
+
+       return NL_STOP;
+}
+
+
+static int cb_error_handler2(_unused struct sockaddr_nl *nla, struct nlmsgerr *err,
+               void *arg)
+{
+       struct neigh_info *ctxt = (struct neigh_info *)arg;
+
+       ctxt->pending = 0;
+       ctxt->ret = err->error;
+
+       return NL_STOP;
+}
+
+/* Detect an IPV6-address proxy neighbor for the given interface */
+int netlink_get_interface_proxy_neigh(int ifindex, const struct in6_addr *addr)
+{
+       struct nl_msg *msg;
+       struct ndmsg ndm = {
+               .ndm_family = AF_INET6,
+               .ndm_flags = NTF_PROXY,
+               .ndm_ifindex = ifindex,
+       };
+       struct nl_cb *cb = nl_cb_alloc(NL_CB_DEFAULT);
+       struct neigh_info ctxt = {
+               .ifindex = ifindex,
+               .addr = addr,
+               .ret = 0,
+               .pending = 1,
+       };
+
+       if (!cb) {
+               ctxt.ret = -1;
+               goto out;
+       }
+
+       msg = nlmsg_alloc_simple(RTM_GETNEIGH, NLM_F_REQUEST | NLM_F_MATCH);
+
+       if (!msg) {
+               ctxt.ret = -1;
+               goto out;
+       }
+
+       nlmsg_append(msg, &ndm, sizeof(ndm), 0);
+       nla_put(msg, NDA_DST, sizeof(*addr), addr);
+
+       nl_cb_set(cb, NL_CB_VALID, NL_CB_CUSTOM, cb_valid_handler2, &ctxt);
+       nl_cb_set(cb, NL_CB_FINISH, NL_CB_CUSTOM, cb_finish_handler2, &ctxt);
+       nl_cb_err(cb, NL_CB_CUSTOM, cb_error_handler2, &ctxt);
+
+       nl_send_auto_complete(rtnl_socket, msg);
+       while (ctxt.pending > 0)
+               nl_recvmsgs(rtnl_socket, cb);
+
+       nlmsg_free(msg);
+
+out:
+       nl_cb_put(cb);
+
+       return ctxt.ret;
+}
+
+
 int netlink_setup_route(const struct in6_addr *addr, const int prefixlen,
                const int ifindex, const struct in6_addr *gw,
                const uint32_t metric, const bool add)