neigh.c

/*
 * lib/route/neigh.c    Neighbours
 *
 *      This library is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU Lesser General Public
 *      License as published by the Free Software Foundation version 2.1
 *      of the License.
 *
 * Copyright (c) 2003-2006 Thomas Graf <tgraf@suug.ch>
 */
 
/**
 * @ingroup rtnl
 * @defgroup neigh Neighbours
 * @brief
 *
 * The neighbour table establishes bindings between protocol addresses and
 * link layer addresses for hosts sharing the same physical link. This
 * module allows you to access and manipulate the content of these tables.
 *
 * @par Neighbour States
 * @code
 * NUD_INCOMPLETE
 * NUD_REACHABLE
 * NUD_STALE
 * NUD_DELAY
 * NUD_PROBE
 * NUD_FAILED
 * NUD_NOARP
 * NUD_PERMANENT
 * @endcode
 *
 * @par Neighbour Flags
 * @code
 * NTF_PROXY
 * NTF_ROUTER
 * @endcode
 *
 * @par Neighbour Identification
 * A neighbour is uniquely identified by the attributes listed below, whenever
 * you refer to an existing neighbour all of the attributes must be set.
 * Neighbours from caches automatically have all required attributes set.
 *   - interface index (rtnl_neigh_set_ifindex())
 *   - destination address (rtnl_neigh_set_dst())
 *
 * @par Changeable Attributes
 * \anchor neigh_changeable
 *  - state (rtnl_neigh_set_state())
 *  - link layer address (rtnl_neigh_set_lladdr())
 *
 * @par Required Caches for Dumping
 * In order to dump neighbour attributes you must provide the following
 * caches via nl_cache_provide()
 *  - link cache holding all links
 *
 * @par TODO
 *   - Document proxy settings
 *   - Document states and their influence
 *
 * @par 1) Retrieving information about configured neighbours
 * @code
 * // The first step is to retrieve a list of all available neighbour within
 * // the kernel and put them into a cache.
 * struct nl_cache *cache = rtnl_neigh_alloc_cache(handle);
 *
 * // Neighbours can then be looked up by the interface and destination
 * // address:
 * struct rtnl_neigh *neigh = rtnl_neigh_get(cache, ifindex, dst_addr);
 * 
 * // After successful usage, the object must be given back to the cache
 * rtnl_neigh_put(neigh);
 * @endcode
 *
 * @par 2) Adding new neighbours
 * @code
 * // Allocate an empty neighbour handle to be filled out with the attributes
 * // of the new neighbour.
 * struct rtnl_neigh *neigh = rtnl_neigh_alloc();
 *
 * // Fill out the attributes of the new neighbour
 * rtnl_neigh_set_ifindex(neigh, ifindex);
 * rtnl_neigh_set_dst(neigh, dst_addr);
 * rtnl_neigh_set_state(neigh, rtnl_neigh_str2state("permanent"));
 *
 * // Build the netlink message and send it to the kernel, the operation will
 * // block until the operation has been completed. Alternatively the required
 * // netlink message can be built using rtnl_neigh_build_add_request()
 * // to be sent out using nl_send_auto_complete().
 * rtnl_neigh_add(nl_handle, neigh, NLM_F_REPLACE);
 *
 * // Free the memory
 * rtnl_neigh_put(neigh);
 * @endcode
 *
 * @par 3) Deleting an existing neighbour
 * @code
 * // Allocate an empty neighbour object to be filled out with the attributes
 * // matching the neighbour to be deleted. Alternatively a fully equipped
 * // neighbour object out of a cache can be used instead.
 * struct rtnl_neigh *neigh = rtnl_neigh_alloc();
 *
 * // Neighbours are uniquely identified by their interface index and
 * // destination address, you may fill out other attributes but they
 * // will have no influence.
 * rtnl_neigh_set_ifindex(neigh, ifindex);
 * rtnl_neigh_set_dst(neigh, dst_addr);
 *
 * // Build the netlink message and send it to the kernel, the operation will
 * // block until the operation has been completed. Alternatively the required
 * // netlink message can be built using rtnl_neigh_build_delete_request()
 * // to be sent out using nl_send_auto_complete().
 * rtnl_neigh_delete(handle, neigh, 0);
 *
 * // Free the memory
 * rtnl_neigh_put(neigh);
 * @endcode
 *
 * @par 4) Changing neighbour attributes
 * @code
 * // Allocate an empty neighbour object to be filled out with the attributes
 * // matching the neighbour to be changed and the new parameters. Alternatively
 * // a fully equipped modified neighbour object out of a cache can be used.
 * struct rtnl_neigh *neigh = rtnl_neigh_alloc();
 *
 * // Identify the neighbour to be changed by its interface index and
 * // destination address
 * rtnl_neigh_set_ifindex(neigh, ifindex);
 * rtnl_neigh_set_dst(neigh, dst_addr);
 *
 * // The link layer address may be modified, if so it is wise to change
 * // its state to "permanent" in order to avoid having it overwritten.
 * rtnl_neigh_set_lladdr(neigh, lladdr);
 *
 * // Secondly the state can be modified allowing normal neighbours to be
 * // converted into permanent entries or to manually confirm a neighbour.
 * rtnl_neigh_set_state(neigh, state);
 *
 * // Build the netlink message and send it to the kernel, the operation will
 * // block until the operation has been completed. Alternatively the required
 * // netlink message can be built using rtnl_neigh_build_change_request()
 * // to be sent out using nl_send_auto_complete().
 * rtnl_neigh_change(handle, neigh, 0);
 *
 * // Free the memory
 * rtnl_neigh_put(neigh);
 * @endcode
 * @{
 */
 
#include <netlink-local.h>
#include <netlink/netlink.h>
#include <netlink/utils.h>
#include <netlink/route/rtnl.h>
#include <netlink/route/neighbour.h>
#include <netlink/route/link.h>
 
/** @cond SKIP */
#define NEIGH_ATTR_FLAGS        0x01
#define NEIGH_ATTR_STATE        0x02
#define NEIGH_ATTR_LLADDR       0x04
#define NEIGH_ATTR_DST          0x08
#define NEIGH_ATTR_CACHEINFO    0x10
#define NEIGH_ATTR_IFINDEX      0x20
#define NEIGH_ATTR_FAMILY       0x40
#define NEIGH_ATTR_TYPE         0x80
#define NEIGH_ATTR_PROBES       0x100
 
static struct nl_cache_ops rtnl_neigh_ops;
static struct nl_object_ops neigh_obj_ops;
/** @endcond */
 
static void neigh_free_data(struct nl_object *c)
{
        struct rtnl_neigh *neigh = nl_object_priv(c);
 
        if (!neigh)
                return;
 
        nl_addr_put(neigh->n_lladdr);
        nl_addr_put(neigh->n_dst);
}
 
static int neigh_clone(struct nl_object *_dst, struct nl_object *_src)
{
        struct rtnl_neigh *dst = nl_object_priv(_dst);
        struct rtnl_neigh *src = nl_object_priv(_src);
 
        if (src->n_lladdr)
                if (!(dst->n_lladdr = nl_addr_clone(src->n_lladdr)))
                        goto errout;
 
        if (src->n_dst)
                if (!(dst->n_dst = nl_addr_clone(src->n_dst)))
                        goto errout;
 
        return 0;
errout:
        return nl_get_errno();
}
 
static int neigh_compare(struct nl_object *_a, struct nl_object *_b,
                        uint32_t attrs, int flags)
{
        struct rtnl_neigh *a = (struct rtnl_neigh *) _a;
        struct rtnl_neigh *b = (struct rtnl_neigh *) _b;
        int diff = 0;
 
#define NEIGH_DIFF(ATTR, EXPR) ATTR_DIFF(attrs, NEIGH_ATTR_##ATTR, a, b, EXPR)
 
        diff |= NEIGH_DIFF(IFINDEX,     a->n_ifindex != b->n_ifindex);
        diff |= NEIGH_DIFF(FAMILY,      a->n_family != b->n_family);
        diff |= NEIGH_DIFF(TYPE,        a->n_type != b->n_type);
        diff |= NEIGH_DIFF(LLADDR,      nl_addr_cmp(a->n_lladdr, b->n_lladdr));
        diff |= NEIGH_DIFF(DST,         nl_addr_cmp(a->n_dst, b->n_dst));
 
        if (flags & LOOSE_FLAG_COMPARISON) {
                diff |= NEIGH_DIFF(STATE,
                                  (a->n_state ^ b->n_state) & b->n_state_mask);
                diff |= NEIGH_DIFF(FLAGS,
                                  (a->n_flags ^ b->n_flags) & b->n_flag_mask);
        } else {
                diff |= NEIGH_DIFF(STATE, a->n_state != b->n_state);
                diff |= NEIGH_DIFF(FLAGS, a->n_flags != b->n_flags);
        }
 
#undef NEIGH_DIFF
 
        return diff;
}
 
static struct trans_tbl neigh_attrs[] = {
        __ADD(NEIGH_ATTR_FLAGS, flags)
        __ADD(NEIGH_ATTR_STATE, state)
        __ADD(NEIGH_ATTR_LLADDR, lladdr)
        __ADD(NEIGH_ATTR_DST, dst)
        __ADD(NEIGH_ATTR_CACHEINFO, cacheinfo)
        __ADD(NEIGH_ATTR_IFINDEX, ifindex)
        __ADD(NEIGH_ATTR_FAMILY, family)
        __ADD(NEIGH_ATTR_TYPE, type)
        __ADD(NEIGH_ATTR_PROBES, probes)
};
 
static char *neigh_attrs2str(int attrs, char *buf, size_t len)
{
        return __flags2str(attrs, buf, len, neigh_attrs,
                           ARRAY_SIZE(neigh_attrs));
}
 
static struct nla_policy neigh_policy[NDA_MAX+1] = {
        [NDA_CACHEINFO] = { .minlen = sizeof(struct nda_cacheinfo) },
        [NDA_PROBES]    = { .type = NLA_U32 },
};
 
static int neigh_msg_parser(struct nl_cache_ops *ops, struct sockaddr_nl *who,
                            struct nlmsghdr *n, struct nl_parser_param *pp)
{
        struct rtnl_neigh *neigh;
        struct nlattr *tb[NDA_MAX + 1];
        struct ndmsg *nm;
        int err;
 
        neigh = rtnl_neigh_alloc();
        if (!neigh) {
                err = nl_errno(ENOMEM);
                goto errout;
        }
 
        neigh->ce_msgtype = n->nlmsg_type;
        nm = nlmsg_data(n);
 
        err = nlmsg_parse(n, sizeof(*nm), tb, NDA_MAX, neigh_policy);
        if (err < 0)
                goto errout;
 
        neigh->n_family  = nm->ndm_family;
        neigh->n_ifindex = nm->ndm_ifindex;
        neigh->n_state   = nm->ndm_state;
        neigh->n_flags   = nm->ndm_flags;
        neigh->n_type    = nm->ndm_type;
 
        neigh->ce_mask |= (NEIGH_ATTR_FAMILY | NEIGH_ATTR_IFINDEX |
                           NEIGH_ATTR_STATE | NEIGH_ATTR_FLAGS |
                           NEIGH_ATTR_TYPE);
 
        if (tb[NDA_LLADDR]) {
                neigh->n_lladdr = nla_get_addr(tb[NDA_LLADDR], AF_UNSPEC);
                if (!neigh->n_lladdr)
                        goto errout;
                nl_addr_set_family(neigh->n_lladdr,
                                   nl_addr_guess_family(neigh->n_lladdr));
                neigh->ce_mask |= NEIGH_ATTR_LLADDR;
        }
 
        if (tb[NDA_DST]) {
                neigh->n_dst = nla_get_addr(tb[NDA_DST], neigh->n_family);
                if (!neigh->n_dst)
                        goto errout;
                neigh->ce_mask |= NEIGH_ATTR_DST;
        }
 
        if (tb[NDA_CACHEINFO]) {
                struct nda_cacheinfo *ci = nla_data(tb[NDA_CACHEINFO]);
 
                neigh->n_cacheinfo.nci_confirmed = ci->ndm_confirmed;
                neigh->n_cacheinfo.nci_used = ci->ndm_used;
                neigh->n_cacheinfo.nci_updated = ci->ndm_updated;
                neigh->n_cacheinfo.nci_refcnt = ci->ndm_refcnt;
                
                neigh->ce_mask |= NEIGH_ATTR_CACHEINFO;
        }
 
        if (tb[NDA_PROBES]) {
                neigh->n_probes = nla_get_u32(tb[NDA_PROBES]);
                neigh->ce_mask |= NEIGH_ATTR_PROBES;
        }
 
        err = pp->pp_cb((struct nl_object *) neigh, pp);
        if (err < 0)
                goto errout;
 
        err = P_ACCEPT;
 
errout:
        rtnl_neigh_put(neigh);
        return err;
}
 
static int neigh_request_update(struct nl_cache *c, struct nl_handle *h)
{
        return nl_rtgen_request(h, RTM_GETNEIGH, AF_UNSPEC, NLM_F_DUMP);
}
 
 
static int neigh_dump_brief(struct nl_object *a, struct nl_dump_params *p)
{
        char dst[INET6_ADDRSTRLEN+5], lladdr[INET6_ADDRSTRLEN+5];
        struct rtnl_neigh *n = (struct rtnl_neigh *) a;
        struct nl_cache *link_cache;
        char state[128], flags[64];
 
        link_cache = nl_cache_mngt_require("route/link");
 
        dp_dump(p, "%s ", nl_addr2str(n->n_dst, dst, sizeof(dst)));
 
        if (link_cache)
                dp_dump(p, "dev %s ",
                        rtnl_link_i2name(link_cache, n->n_ifindex,
                                         state, sizeof(state)));
        else
                dp_dump(p, "dev %d ", n->n_ifindex);
 
        if (n->ce_mask & NEIGH_ATTR_LLADDR)
                dp_dump(p, "lladdr %s ",
                        nl_addr2str(n->n_lladdr, lladdr, sizeof(lladdr)));
 
        rtnl_neigh_state2str(n->n_state, state, sizeof(state));
        rtnl_neigh_flags2str(n->n_flags, flags, sizeof(flags));
 
        if (state[0])
                dp_dump(p, "<%s", state);
        if (flags[0])
                dp_dump(p, "%s%s", state[0] ? "," : "<", flags);
        if (state[0] || flags[0])
                dp_dump(p, ">");
        dp_dump(p, "\n");
 
        return 1;
}
 
static int neigh_dump_full(struct nl_object *a, struct nl_dump_params *p)
{
        char rtn_type[32];
        struct rtnl_neigh *n = (struct rtnl_neigh *) a;
        int hz = nl_get_hz();
 
        int line = neigh_dump_brief(a, p);
 
        dp_dump_line(p, line++, "    refcnt %u type %s confirmed %u used "
                                "%u updated %u\n",
                n->n_cacheinfo.nci_refcnt,
                nl_rtntype2str(n->n_type, rtn_type, sizeof(rtn_type)),
                n->n_cacheinfo.nci_confirmed/hz,
                n->n_cacheinfo.nci_used/hz, n->n_cacheinfo.nci_updated/hz);
 
        return line;
}
 
static int neigh_dump_stats(struct nl_object *a, struct nl_dump_params *p)
{
        return neigh_dump_full(a, p);
}
 
static int neigh_dump_xml(struct nl_object *obj, struct nl_dump_params *p)
{
        struct rtnl_neigh *neigh = (struct rtnl_neigh *) obj;
        char buf[128];
        int line = 0;
 
        dp_dump_line(p, line++, "<neighbour>\n");
        dp_dump_line(p, line++, "  <family>%s</family>\n",
                     nl_af2str(neigh->n_family, buf, sizeof(buf)));
 
        if (neigh->ce_mask & NEIGH_ATTR_LLADDR)
                dp_dump_line(p, line++, "  <lladdr>%s</lladdr>\n",
                             nl_addr2str(neigh->n_lladdr, buf, sizeof(buf)));
 
        if (neigh->ce_mask & NEIGH_ATTR_DST)
                dp_dump_line(p, line++, "  <dst>%s</dst>\n",
                             nl_addr2str(neigh->n_dst, buf, sizeof(buf)));
 
        if (neigh->ce_mask & NEIGH_ATTR_IFINDEX) {
                struct nl_cache *link_cache;
        
                link_cache = nl_cache_mngt_require("route/link");
 
                if (link_cache)
                        dp_dump_line(p, line++, "  <device>%s</device>\n",
                                     rtnl_link_i2name(link_cache,
                                                      neigh->n_ifindex,
                                                      buf, sizeof(buf)));
                else
                        dp_dump_line(p, line++, "  <device>%u</device>\n",
                                     neigh->n_ifindex);
        }
 
        if (neigh->ce_mask & NEIGH_ATTR_PROBES)
                dp_dump_line(p, line++, "  <probes>%u</probes>\n",
                             neigh->n_probes);
 
        if (neigh->ce_mask & NEIGH_ATTR_TYPE)
                dp_dump_line(p, line++, "  <type>%s</type>\n",
                             nl_rtntype2str(neigh->n_type, buf, sizeof(buf)));
 
        rtnl_neigh_flags2str(neigh->n_flags, buf, sizeof(buf));
        if (buf[0])
                dp_dump_line(p, line++, "  <flags>%s</flags>\n", buf);
 
        rtnl_neigh_state2str(neigh->n_state, buf, sizeof(buf));
        if (buf[0])
                dp_dump_line(p, line++, "  <state>%s</state>\n", buf);
 
        dp_dump_line(p, line++, "</neighbour>\n");
 
#if 0
        struct rtnl_ncacheinfo n_cacheinfo;
#endif
 
        return line;
}
 
static int neigh_dump_env(struct nl_object *obj, struct nl_dump_params *p)
{
        struct rtnl_neigh *neigh = (struct rtnl_neigh *) obj;
        char buf[128];
        int line = 0;
 
        dp_dump_line(p, line++, "NEIGH_FAMILY=%s\n",
                     nl_af2str(neigh->n_family, buf, sizeof(buf)));
 
        if (neigh->ce_mask & NEIGH_ATTR_LLADDR)
                dp_dump_line(p, line++, "NEIGHT_LLADDR=%s\n",
                             nl_addr2str(neigh->n_lladdr, buf, sizeof(buf)));
 
        if (neigh->ce_mask & NEIGH_ATTR_DST)
                dp_dump_line(p, line++, "NEIGH_DST=%s\n",
                             nl_addr2str(neigh->n_dst, buf, sizeof(buf)));
 
        if (neigh->ce_mask & NEIGH_ATTR_IFINDEX) {
                struct nl_cache *link_cache;
 
                dp_dump_line(p, line++, "NEIGH_IFINDEX=%u\n",
                             neigh->n_ifindex);
 
                link_cache = nl_cache_mngt_require("route/link");
                if (link_cache)
                        dp_dump_line(p, line++, "NEIGH_IFNAME=%s\n",
                                     rtnl_link_i2name(link_cache,
                                                      neigh->n_ifindex,
                                                      buf, sizeof(buf)));
        }
 
        if (neigh->ce_mask & NEIGH_ATTR_PROBES)
                dp_dump_line(p, line++, "NEIGH_PROBES=%u\n",
                             neigh->n_probes);
 
        if (neigh->ce_mask & NEIGH_ATTR_TYPE)
                dp_dump_line(p, line++, "NEIGH_TYPE=%s\n",
                             nl_rtntype2str(neigh->n_type, buf, sizeof(buf)));
 
        rtnl_neigh_flags2str(neigh->n_flags, buf, sizeof(buf));
        if (buf[0])
                dp_dump_line(p, line++, "NEIGH_FLAGS=%s\n", buf);
 
        rtnl_neigh_state2str(neigh->n_state, buf, sizeof(buf));
        if (buf[0])
                dp_dump_line(p, line++, "NEIGH_STATE=%s\n", buf);
 
        return line;
}
 
/**
 * @name Neighbour Object Allocation/Freeage
 * @{
 */
 
struct rtnl_neigh *rtnl_neigh_alloc(void)
{
        return (struct rtnl_neigh *) nl_object_alloc(&neigh_obj_ops);
}
 
void rtnl_neigh_put(struct rtnl_neigh *neigh)
{
        nl_object_put((struct nl_object *) neigh);
}
 
/** @} */
 
/**
 * @name Neighbour Cache Managament
 * @{
 */
 
/**
 * Build a neighbour cache including all neighbours currently configured in the kernel.
 * @arg handle          netlink handle
 *
 * Allocates a new neighbour cache, initializes it properly and updates it
 * to include all neighbours currently configured in the kernel.
 *
 * @note The caller is responsible for destroying and freeing the
 *       cache after using it.
 * @return The new cache or NULL if an error occured.
 */
struct nl_cache *rtnl_neigh_alloc_cache(struct nl_handle *handle)
{
        struct nl_cache *cache;
 
        cache = nl_cache_alloc(&rtnl_neigh_ops);
        if (cache == NULL)
                return NULL;
 
        if (handle && nl_cache_refill(handle, cache) < 0) {
                nl_cache_free(cache);
                return NULL;
        }
 
        NL_DBG(2, "Returning new cache %p\n", cache);
 
        return cache;
}
 
/**
 * Look up a neighbour by interface index and destination address
 * @arg cache           neighbour cache
 * @arg ifindex         interface index the neighbour is on
 * @arg dst             destination address of the neighbour
 * @return neighbour handle or NULL if no match was found.
 */
struct rtnl_neigh * rtnl_neigh_get(struct nl_cache *cache, int ifindex,
                                   struct nl_addr *dst)
{
        struct rtnl_neigh *neigh;
 
        nl_list_for_each_entry(neigh, &cache->c_items, ce_list) {
                if (neigh->n_ifindex == ifindex &&
                    !nl_addr_cmp(neigh->n_dst, dst)) {
                        nl_object_get((struct nl_object *) neigh);
                        return neigh;
                }
        }
 
        return NULL;
}
 
/** @} */
 
/**
 * @name Neighbour Addition
 * @{
 */
 
static struct nl_msg * build_neigh_msg(struct rtnl_neigh *tmpl, int cmd,
                                       int flags)
{
        struct nl_msg *msg;
        struct ndmsg nhdr = {
                .ndm_ifindex = tmpl->n_ifindex,
                .ndm_family = nl_addr_get_family(tmpl->n_dst),
                .ndm_state = NUD_PERMANENT,
        };
 
        if (tmpl->ce_mask & NEIGH_ATTR_STATE)
                nhdr.ndm_state = tmpl->n_state;
 
        msg = nlmsg_alloc_simple(cmd, flags);
        if (!msg)
                return NULL;
 
        if (nlmsg_append(msg, &nhdr, sizeof(nhdr), NLMSG_ALIGNTO) < 0)
                goto nla_put_failure;
 
        NLA_PUT_ADDR(msg, NDA_DST, tmpl->n_dst);
 
        if (tmpl->ce_mask & NEIGH_ATTR_LLADDR)
                NLA_PUT_ADDR(msg, NDA_LLADDR, tmpl->n_lladdr);
 
        return msg;
 
nla_put_failure:
        nlmsg_free(msg);
        return NULL;
}
 
/**
 * Build netlink request message to add a new neighbour
 * @arg tmpl            template with data of new neighbour
 * @arg flags           additional netlink message flags
 *
 * 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, int flags)
{
        return build_neigh_msg(tmpl, RTM_NEWNEIGH, NLM_F_CREATE | flags);
}
 
/**
 * Add a new neighbour
 * @arg handle          netlink handle
 * @arg tmpl            template with requested changes
 * @arg flags           additional netlink message flags
 *
 * 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 flags)
{
        int err;
        struct nl_msg *msg;
        
        msg = rtnl_neigh_build_add_request(tmpl, flags);
        if (!msg)
                return nl_errno(ENOMEM);
 
        err = nl_send_auto_complete(handle, msg);
        nlmsg_free(msg);
        if (err < 0)
                return err;
 
        return nl_wait_for_ack(handle);
}
 
/** @} */
 
/**
 * @name Neighbour Deletion
 * @{
 */
 
/**
 * Build a netlink request message to delete a neighbour
 * @arg neigh           neighbour to delete
 * @arg flags           additional netlink message flags
 *
 * Builds a new netlink message requesting a deletion of a 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 neigh must point to an existing
 * neighbour.
 *
 * @return The netlink message
 */
struct nl_msg *rtnl_neigh_build_delete_request(struct rtnl_neigh *neigh,
                                               int flags)
{
        return build_neigh_msg(neigh, RTM_DELNEIGH, flags);
}
 
/**
 * Delete a neighbour
 * @arg handle          netlink handle
 * @arg neigh           neighbour to delete
 * @arg flags           additional netlink message flags
 *
 * Builds a netlink message by calling rtnl_neigh_build_delete_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.
 *
 * @return 0 on sucess or a negative error if an error occured.
 */
int rtnl_neigh_delete(struct nl_handle *handle, struct rtnl_neigh *neigh,
                      int flags)
{
        int err;
        struct nl_msg *msg;
        
        msg = rtnl_neigh_build_delete_request(neigh, flags);
        if (!msg)
                return nl_errno(ENOMEM);
 
        err = nl_send_auto_complete(handle, msg);
        nlmsg_free(msg);
        if (err < 0)
                return err;
 
        return nl_wait_for_ack(handle);
}
 
/** @} */
 
/**
 * @name Neighbour Modification
 * @{
 */
 
/**
 * Build a netlink request message to change neighbour attributes
 * @arg neigh           the neighbour to change
 * @arg flags           additional netlink message flags
 *
 * Builds a new netlink message requesting a change of a neigh
 * attributes. 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.
 *
 * @return The netlink message
 * @note Not all attributes can be changed, see
 *       \ref neigh_changeable "Changeable Attributes" for a list.
 */
struct nl_msg *rtnl_neigh_build_change_request(struct rtnl_neigh *neigh,
                                               int flags)
{
        return build_neigh_msg(neigh, RTM_NEWNEIGH, NLM_F_REPLACE | flags);
}
 
/**
 * Change neighbour attributes
 * @arg handle          netlink handle
 * @arg neigh           neighbour to be changed
 * @arg flags           additional netlink message flags
 *
 * Builds a netlink message by calling rtnl_neigh_build_change_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.
 *
 * @return 0 on sucess or a negative error if an error occured.
 * @note Not all attributes can be changed, see
 *       \ref neigh_changeable "Changeable Attributes" for a list.
 */
int rtnl_neigh_change(struct nl_handle *handle, struct rtnl_neigh *neigh,
                      int flags)
{
        int err;
        struct nl_msg *msg;
        
        msg = rtnl_neigh_build_change_request(neigh, flags);
        if (!msg)
                return nl_errno(ENOMEM);
 
        err = nl_send_auto_complete(handle, msg);
        nlmsg_free(msg);
        if (err < 0)
                return err;
 
        return nl_wait_for_ack(handle);
}
 
/** @} */
 
/**
 * @name Neighbour States Translations
 * @{
 */
 
static struct trans_tbl neigh_states[] = {
        __ADD(NUD_INCOMPLETE, incomplete)
        __ADD(NUD_REACHABLE, reachable)
        __ADD(NUD_STALE, stale)
        __ADD(NUD_DELAY, delay)
        __ADD(NUD_PROBE, probe)
        __ADD(NUD_FAILED, failed)
        __ADD(NUD_NOARP, norarp)
        __ADD(NUD_PERMANENT, permanent)
};
 
char * rtnl_neigh_state2str(int state, char *buf, size_t len)
{
        return __flags2str(state, buf, len, neigh_states,
            ARRAY_SIZE(neigh_states));
}
 
int rtnl_neigh_str2state(const char *name)
{
        return __str2type(name, neigh_states, ARRAY_SIZE(neigh_states));
}
 
/** @} */
 
/**
 * @name Neighbour Flags Translations
 * @{
 */
 
static struct trans_tbl neigh_flags[] = {
        __ADD(NTF_PROXY, proxy)
        __ADD(NTF_ROUTER, router)
};
 
char * rtnl_neigh_flags2str(int flags, char *buf, size_t len)
{
        return __flags2str(flags, buf, len, neigh_flags,
            ARRAY_SIZE(neigh_flags));
}
 
int rtnl_neigh_str2flag(const char *name)
{
        return __str2type(name, neigh_flags, ARRAY_SIZE(neigh_flags));
}
 
/** @} */
 
/**
 * @name Attributes
 * @{
 */
 
void rtnl_neigh_set_state(struct rtnl_neigh *neigh, int state)
{
        neigh->n_state_mask |= state;
        neigh->n_state |= state;
        neigh->ce_mask |= NEIGH_ATTR_STATE;
}
 
int rtnl_neigh_get_state(struct rtnl_neigh *neigh)
{
        if (neigh->ce_mask & NEIGH_ATTR_STATE)
                return neigh->n_state;
        else
                return -1;
}
 
void rtnl_neigh_unset_state(struct rtnl_neigh *neigh, int state)
{
        neigh->n_state_mask |= state;
        neigh->n_state &= ~state;
        neigh->ce_mask |= NEIGH_ATTR_STATE;
}
 
void rtnl_neigh_set_flags(struct rtnl_neigh *neigh, unsigned int flags)
{
        neigh->n_flag_mask |= flags;
        neigh->n_flags |= flags;
        neigh->ce_mask |= NEIGH_ATTR_FLAGS;
}
 
unsigned int rtnl_neigh_get_flags(struct rtnl_neigh *neigh)
{
        return neigh->n_flags;
}
 
void rtnl_neigh_unset_flags(struct rtnl_neigh *neigh, unsigned int flags)
{
        neigh->n_flag_mask |= flags;
        neigh->n_flags &= ~flags;
        neigh->ce_mask |= NEIGH_ATTR_FLAGS;
}
 
void rtnl_neigh_set_ifindex(struct rtnl_neigh *neigh, int ifindex)
{
        neigh->n_ifindex = ifindex;
        neigh->ce_mask |= NEIGH_ATTR_IFINDEX;
}
 
int rtnl_neigh_get_ifindex(struct rtnl_neigh *neigh)
{
        if (neigh->ce_mask & NEIGH_ATTR_IFINDEX)
                return neigh->n_ifindex;
        else
                return RTNL_LINK_NOT_FOUND;
}
 
static inline int __assign_addr(struct rtnl_neigh *neigh, struct nl_addr **pos,
                                struct nl_addr *new, int flag, int nocheck)
{
        if (!nocheck) {
                if (neigh->ce_mask & NEIGH_ATTR_FAMILY) {
                        if (new->a_family != neigh->n_family)
                                return nl_error(EINVAL,
                                                "Address family mismatch");
                } else {
                        neigh->n_family = new->a_family;
                        neigh->ce_mask |= NEIGH_ATTR_FAMILY;
                }
        }
 
        if (*pos)
                nl_addr_put(*pos);
 
        nl_addr_get(new);
        *pos = new;
 
        neigh->ce_mask |= flag;
 
        return 0;
}
 
void rtnl_neigh_set_lladdr(struct rtnl_neigh *neigh, struct nl_addr *addr)
{
        __assign_addr(neigh, &neigh->n_lladdr, addr, NEIGH_ATTR_LLADDR, 1);
}
 
struct nl_addr *rtnl_neigh_get_lladdr(struct rtnl_neigh *neigh)
{
        if (neigh->ce_mask & NEIGH_ATTR_LLADDR)
                return neigh->n_lladdr;
        else
                return NULL;
}
 
int rtnl_neigh_set_dst(struct rtnl_neigh *neigh, struct nl_addr *addr)
{
        return __assign_addr(neigh, &neigh->n_dst, addr,
                             NEIGH_ATTR_DST, 0);
}
 
struct nl_addr *rtnl_neigh_get_dst(struct rtnl_neigh *neigh)
{
        if (neigh->ce_mask & NEIGH_ATTR_DST)
                return neigh->n_dst;
        else
                return NULL;
}
 
void rtnl_neigh_set_family(struct rtnl_neigh *neigh, int family)
{
        neigh->n_family = family;
        neigh->ce_mask |= NEIGH_ATTR_FAMILY;
}
 
void rtnl_neigh_set_type(struct rtnl_neigh *neigh, int type)
{
        neigh->n_type = type;
        neigh->ce_mask = NEIGH_ATTR_TYPE;
}
 
int rtnl_neigh_get_type(struct rtnl_neigh *neigh)
{
        if (neigh->ce_mask & NEIGH_ATTR_TYPE)
                return neigh->n_type;
        else
                return -1;
}
 
/** @} */
 
static struct nl_object_ops neigh_obj_ops = {
        .oo_name                = "route/neigh",
        .oo_size                = sizeof(struct rtnl_neigh),
        .oo_free_data           = neigh_free_data,
        .oo_clone               = neigh_clone,
        .oo_dump[NL_DUMP_BRIEF] = neigh_dump_brief,
        .oo_dump[NL_DUMP_FULL]  = neigh_dump_full,
        .oo_dump[NL_DUMP_STATS] = neigh_dump_stats,
        .oo_dump[NL_DUMP_XML]   = neigh_dump_xml,
        .oo_dump[NL_DUMP_ENV]   = neigh_dump_env,
        .oo_compare             = neigh_compare,
        .oo_attrs2str           = neigh_attrs2str,
        .oo_id_attrs            = (NEIGH_ATTR_DST | NEIGH_ATTR_FAMILY),
};
 
static struct nl_af_group neigh_groups[] = {
        { AF_UNSPEC, RTNLGRP_NEIGH },
        { END_OF_GROUP_LIST },
};
 
static struct nl_cache_ops rtnl_neigh_ops = {
        .co_name                = "route/neigh",
        .co_hdrsize             = sizeof(struct ndmsg),
        .co_msgtypes            = {
                                        { RTM_NEWNEIGH, NL_ACT_NEW, "new" },
                                        { RTM_DELNEIGH, NL_ACT_DEL, "del" },
                                        { RTM_GETNEIGH, NL_ACT_GET, "get" },
                                        END_OF_MSGTYPES_LIST,
                                  },
        .co_protocol            = NETLINK_ROUTE,
        .co_groups              = neigh_groups,
        .co_request_update      = neigh_request_update,
        .co_msg_parser          = neigh_msg_parser,
        .co_obj_ops             = &neigh_obj_ops,
};
 
static void __init neigh_init(void)
{
        nl_cache_mngt_register(&rtnl_neigh_ops);
}
 
static void __exit neigh_exit(void)
{
        nl_cache_mngt_unregister(&rtnl_neigh_ops);
}
 
/** @} */