static struct nl_msg * build_neigh_msg(struct rtnl_neigh *tmpl, int cmd,
int flags)
{
struct nl_msg *m;
struct nlmsghdr n = {
.nlmsg_type = cmd,
.nlmsg_flags = flags,
};
struct ndmsg nm = {
.ndm_ifindex = tmpl->n_ifindex,
.ndm_family = tmpl->n_dst.a_family,
.ndm_state = tmpl->n_state,
};
m = nl_msg_build(&n);
nl_msg_append_raw(m, &nm, sizeof(nm));
nl_msg_append_tlv(m, NDA_DST, &tmpl->n_dst.a_addr, tmpl->n_dst.a_len);
if (tmpl->n_mask & NEIGH_HAS_LLADDR)
nl_msg_append_tlv(m, NDA_LLADDR, &tmpl->n_lladdr.a_addr,
tmpl->n_lladdr.a_len);
return m;
}
/**
* Build netlink request message to add a new neighbour
* @arg tmpl template with data of new neighbour
*
* Builds a new netlink message requesting a addition of a new
* neighbour. The netlink message header isn't fully equipped with
* all relevant fields and must thus be sent out via nl_send_auto_complete()
* or supplemented as needed. \a tmpl must contain the attributes of the new
* neighbour set via \c rtnl_neigh_set_* functions.
*
* The following attributes must be set in the template:
* - Interface index (rtnl_neigh_set_ifindex())
* - State (rtnl_neigh_set_state())
* - Destination address (rtnl_neigh_set_dst())
* - Link layer address (rtnl_neigh_set_lladdr())
*
* @return The netlink message
*/
struct nl_msg * rtnl_neigh_build_add_request(struct rtnl_neigh *tmpl)
{
return build_neigh_msg(tmpl, RTM_NEWNEIGH, NLM_F_CREATE);
}
/**
* Add a new neighbour
* @arg handle netlink handle
* @arg tmpl template with requested changes
*
* Builds a netlink message by calling rtnl_neigh_build_add_request(),
* sends the request to the kernel and waits for the next ACK to be
* received and thus blocks until the request has been fullfilled.
*
* The following attributes must be set in the template:
* - Interface index (rtnl_neigh_set_ifindex())
* - State (rtnl_neigh_set_state())
* - Destination address (rtnl_neigh_set_dst())
* - Link layer address (rtnl_neigh_set_lladdr())
*
* @return 0 on sucess or a negative error if an error occured.
*/
int rtnl_neigh_add(struct nl_handle *handle, struct rtnl_neigh *tmpl)
{
int err;
struct nl_msg *m = rtnl_neigh_build_add_request(tmpl);
if ((err = nl_send_auto_complete(handle, nl_msg_get(m))) < 0)
return err;
nl_msg_free(m);
return nl_wait_for_ack(handle);
}
int nl_bridge::learn_source_mac(rtnl_link *br_link, packet *p) {
// we still assume vlan filtering bridge
assert(rtnl_link_get_family(br_link) == AF_BRIDGE);
VLOG(2) << __FUNCTION__ << ": pkt " << p << " on link " << OBJ_CAST(br_link);
rtnl_link_bridge_vlan *br_vlan = rtnl_link_bridge_get_port_vlan(br_link);
if (br_vlan == nullptr) {
LOG(ERROR) << __FUNCTION__
<< ": only the vlan filtering bridge is supported";
return -EINVAL;
}
// parse ether frame and check for vid
vlan_hdr *hdr = reinterpret_cast<basebox::vlan_hdr *>(p->data);
uint16_t vid = 0;
// XXX TODO maybe move this to the utils to have a std lib for parsing the
// ether frame
switch (ntohs(hdr->eth.h_proto)) {
case ETH_P_8021Q:
// vid
vid = ntohs(hdr->vlan);
break;
default:
// no vid, set vid to pvid
vid = br_vlan->pvid;
LOG(WARNING) << __FUNCTION__ << ": assuming untagged for ethertype "
<< std::showbase << std::hex << ntohs(hdr->eth.h_proto);
break;
}
// verify that the vid is in use here
if (!is_vid_set(vid, br_vlan->vlan_bitmap)) {
LOG(WARNING) << __FUNCTION__ << ": got packet on unconfigured port";
return -ENOTSUP;
}
// set nl neighbour to NL
std::unique_ptr<nl_addr, decltype(&nl_addr_put)> h_src(
nl_addr_build(AF_LLC, hdr->eth.h_source, sizeof(hdr->eth.h_source)),
nl_addr_put);
if (!h_src) {
LOG(ERROR) << __FUNCTION__ << ": failed to allocate src mac";
return -ENOMEM;
}
std::unique_ptr<rtnl_neigh, decltype(&rtnl_neigh_put)> n(rtnl_neigh_alloc(),
rtnl_neigh_put);
rtnl_neigh_set_ifindex(n.get(), rtnl_link_get_ifindex(br_link));
rtnl_neigh_set_master(n.get(), rtnl_link_get_master(br_link));
rtnl_neigh_set_family(n.get(), AF_BRIDGE);
rtnl_neigh_set_vlan(n.get(), vid);
rtnl_neigh_set_lladdr(n.get(), h_src.get());
rtnl_neigh_set_flags(n.get(), NTF_MASTER | NTF_EXT_LEARNED);
rtnl_neigh_set_state(n.get(), NUD_REACHABLE);
// check if entry already exists in cache
if (is_mac_in_l2_cache(n.get())) {
return 0;
}
nl_msg *msg = nullptr;
rtnl_neigh_build_add_request(n.get(),
NLM_F_REQUEST | NLM_F_CREATE | NLM_F_EXCL, &msg);
assert(msg);
// send the message and create new fdb entry
if (nl->send_nl_msg(msg) < 0) {
LOG(ERROR) << __FUNCTION__ << ": failed to send netlink message";
return -EINVAL;
}
// cache the entry
if (nl_cache_add(l2_cache.get(), OBJ_CAST(n.get())) < 0) {
LOG(ERROR) << __FUNCTION__ << ": failed to add entry to l2_cache "
<< OBJ_CAST(n.get());
return -EINVAL;
}
VLOG(2) << __FUNCTION__ << ": learned new source mac " << OBJ_CAST(n.get());
return 0;
}
