inet.c

/* SPDX-License-Identifier: LGPL-2.1-only */
/*
 * Copyright (c) 2010 Thomas Graf <tgraf@suug.ch>
 */
 
/**
 * @ingroup link_API
 * @defgroup link_inet IPv4 Link Module
 * @brief Implementation of IPv4 specific link attributes
 *
 *
 *
 * @par Example: Reading the value of IPV4_DEVCONF_FORWARDING
 * @code
 * struct nl_cache *cache;
 * struct rtnl_link *link;
 * uint32_t value;
 *
 * // Allocate a link cache
 * rtnl_link_alloc_cache(sock, AF_UNSPEC, &cache);
 *
 * // Search for the link we wish to see the value from
 * link = rtnl_link_get_by_name(cache, "eth0");
 *
 * // Read the value of the setting IPV4_DEVCONF_FORWARDING
 * if (rtnl_link_inet_get_conf(link, IPV4_DEVCONF_FORWARDING, &value) < 0)
 *         // Error: Unable to read config setting
 *
 * printf("forwarding is %s\n", value ? "enabled" : "disabled");
 * @endcode
 *
 * @par Example: Changing the value of IPV4_DEVCONF_FOWARDING
 * @code
 * //
 * // ... Continueing from the previous example ...
 * //
 *
 * struct rtnl_link *new;
 *
 * // Allocate a new link to store the changes we wish to make.
 * new = rtnl_link_alloc();
 *
 * // Set IPV4_DEVCONF_FORWARDING to '1'
 * rtnl_link_inet_set_conf(new, IPV4_DEVCONF_FORWARDING, 1);
 *
 * // Send the change request to the kernel.
 * rtnl_link_change(sock, link, new, 0);
 * @endcode
 *
 * @{
 */
 
 
#include <netlink-private/netlink.h>
#include <netlink/netlink.h>
#include <netlink/attr.h>
#include <netlink/route/rtnl.h>
#include <netlink/route/link/inet.h>
#include <netlink-private/route/link/api.h>
 
/** @cond SKIP */
struct inet_data
{
        uint8_t                 i_confset[IPV4_DEVCONF_MAX];
        uint32_t                i_conf[IPV4_DEVCONF_MAX];
};
/** @endcond */
 
static void *inet_alloc(struct rtnl_link *link)
{
        return calloc(1, sizeof(struct inet_data));
}
 
static void *inet_clone(struct rtnl_link *link, void *data)
{
        struct inet_data *id;
 
        if ((id = inet_alloc(link)))
                memcpy(id, data, sizeof(*id));
 
        return id;
}
 
static void inet_free(struct rtnl_link *link, void *data)
{
        free(data);
}
 
static struct nla_policy inet_policy[IFLA_INET_MAX+1] = {
        [IFLA_INET_CONF]        = { .minlen = 4 },
};
 
static int inet_parse_af(struct rtnl_link *link, struct nlattr *attr, void *data)
{
        struct inet_data *id = data;
        struct nlattr *tb[IFLA_INET_MAX+1];
        int err;
 
        err = nla_parse_nested(tb, IFLA_INET_MAX, attr, inet_policy);
        if (err < 0)
                return err;
        if (tb[IFLA_INET_CONF] && nla_len(tb[IFLA_INET_CONF]) % 4)
                return -EINVAL;
 
        if (tb[IFLA_INET_CONF]) {
                int i;
                int len = min_t(int, IPV4_DEVCONF_MAX, nla_len(tb[IFLA_INET_CONF]) / 4);
 
                for (i = 0; i < len; i++)
                        id->i_confset[i] = 1;
                nla_memcpy(&id->i_conf, tb[IFLA_INET_CONF], sizeof(id->i_conf));
        }
 
        return 0;
}
 
static int inet_fill_af(struct rtnl_link *link, struct nl_msg *msg, void *data)
{
        struct inet_data *id = data;
        struct nlattr *nla;
        int i;
 
        if (!(nla = nla_nest_start(msg, IFLA_INET_CONF)))
                return -NLE_MSGSIZE;
 
        for (i = 0; i < IPV4_DEVCONF_MAX; i++)
                if (id->i_confset[i])
                        NLA_PUT_U32(msg, i+1, id->i_conf[i]);
 
        nla_nest_end(msg, nla);
 
        return 0;
 
nla_put_failure:
        return -NLE_MSGSIZE;
}
 
static const struct trans_tbl inet_devconf[] = {
        __ADD(IPV4_DEVCONF_FORWARDING, forwarding),
        __ADD(IPV4_DEVCONF_MC_FORWARDING, mc_forwarding),
        __ADD(IPV4_DEVCONF_PROXY_ARP, proxy_arp),
        __ADD(IPV4_DEVCONF_ACCEPT_REDIRECTS, accept_redirects),
        __ADD(IPV4_DEVCONF_SECURE_REDIRECTS, secure_redirects),
        __ADD(IPV4_DEVCONF_SEND_REDIRECTS, send_redirects),
        __ADD(IPV4_DEVCONF_SHARED_MEDIA, shared_media),
        __ADD(IPV4_DEVCONF_RP_FILTER, rp_filter),
        __ADD(IPV4_DEVCONF_ACCEPT_SOURCE_ROUTE, accept_source_route),
        __ADD(IPV4_DEVCONF_BOOTP_RELAY, bootp_relay),
        __ADD(IPV4_DEVCONF_LOG_MARTIANS, log_martians),
        __ADD(IPV4_DEVCONF_TAG, tag),
        __ADD(IPV4_DEVCONF_ARPFILTER, arpfilter),
        __ADD(IPV4_DEVCONF_MEDIUM_ID, medium_id),
        __ADD(IPV4_DEVCONF_NOXFRM, noxfrm),
        __ADD(IPV4_DEVCONF_NOPOLICY, nopolicy),
        __ADD(IPV4_DEVCONF_FORCE_IGMP_VERSION, force_igmp_version),
        __ADD(IPV4_DEVCONF_ARP_ANNOUNCE, arp_announce),
        __ADD(IPV4_DEVCONF_ARP_IGNORE, arp_ignore),
        __ADD(IPV4_DEVCONF_PROMOTE_SECONDARIES, promote_secondaries),
        __ADD(IPV4_DEVCONF_ARP_ACCEPT, arp_accept),
        __ADD(IPV4_DEVCONF_ARP_NOTIFY, arp_notify),
        __ADD(IPV4_DEVCONF_ACCEPT_LOCAL, accept_local),
        __ADD(IPV4_DEVCONF_SRC_VMARK, src_vmark),
        __ADD(IPV4_DEVCONF_PROXY_ARP_PVLAN, proxy_arp_pvlan),
        __ADD(IPV4_DEVCONF_ROUTE_LOCALNET, route_localnet),
        __ADD(IPV4_DEVCONF_IGMPV2_UNSOLICITED_REPORT_INTERVAL, igmpv2_unsolicited_report_interval),
        __ADD(IPV4_DEVCONF_IGMPV3_UNSOLICITED_REPORT_INTERVAL, igmpv3_unsolicited_report_interval),
};
 
const char *rtnl_link_inet_devconf2str(int type, char *buf, size_t len)
{
        return __type2str(type, buf, len, inet_devconf,
                          ARRAY_SIZE(inet_devconf));
}
 
int rtnl_link_inet_str2devconf(const char *name)
{
        return __str2type(name, inet_devconf, ARRAY_SIZE(inet_devconf));
}
 
static void inet_dump_details(struct rtnl_link *link,
                              struct nl_dump_params *p, void *data)
{
        struct inet_data *id = data;
        char buf[64];
        int i, n = 0;
 
        nl_dump_line(p, "    ipv4 devconf:\n");
        nl_dump_line(p, "      ");
 
        for (i = 0; i < IPV4_DEVCONF_MAX; i++) {
                nl_dump_line(p, "%-19s %3u",
                        rtnl_link_inet_devconf2str(i+1, buf, sizeof(buf)),
                        id->i_confset[i] ? id->i_conf[i] : 0);
 
                if (++n == 3) {
                        nl_dump(p, "\n");
                        nl_dump_line(p, "      ");
                        n = 0;
                } else
                        nl_dump(p, "  ");
        }
 
        if (n != 0)
                nl_dump(p, "\n");
}
 
static struct rtnl_link_af_ops inet_ops = {
        .ao_family                      = AF_INET,
        .ao_alloc                       = &inet_alloc,
        .ao_clone                       = &inet_clone,
        .ao_free                        = &inet_free,
        .ao_parse_af                    = &inet_parse_af,
        .ao_fill_af                     = &inet_fill_af,
        .ao_dump[NL_DUMP_DETAILS]       = &inet_dump_details,
};
 
/**
 * Get value of a ipv4 link configuration setting
 * @arg link            Link object
 * @arg cfgid           Configuration identifier
 * @arg res             Result pointer
 *
 * Stores the value of the specified configuration setting in the provided
 * result pointer.
 *
 * @return 0 on success or a negative error code.
 * @return -NLE_RANGE cfgid is out of range, 1..IPV4_DEVCONF_MAX
 * @return -NLE_NOATTR configuration setting not available
 * @return -NLE_INVAL cfgid not set. If the link was received via netlink,
 *                    it means that the cfgid is not supported.
 */
int rtnl_link_inet_get_conf(struct rtnl_link *link, const unsigned int cfgid,
                            uint32_t *res)
{
        struct inet_data *id;
 
        if (cfgid == 0 || cfgid > IPV4_DEVCONF_MAX)
                return -NLE_RANGE;
 
        if (!(id = rtnl_link_af_data(link, &inet_ops)))
                return -NLE_NOATTR;
 
        if (!id->i_confset[cfgid - 1])
                return -NLE_INVAL;
        *res = id->i_conf[cfgid - 1];
 
        return 0;
}
 
/**
 * Change value of a ipv4 link configuration setting
 * @arg link            Link object
 * @arg cfgid           Configuration identifier
 * @arg value           New value
 *
 * Changes the value in the per link ipv4 configuration array. 
 *
 * @return 0 on success or a negative error code.
 * @return -NLE_RANGE cfgid is out of range, 1..IPV4_DEVCONF_MAX
 * @return -NLE_NOMEM memory allocation failed
 */
int rtnl_link_inet_set_conf(struct rtnl_link *link, const unsigned int cfgid,
                            uint32_t value)
{
        struct inet_data *id;
 
        if (!(id = rtnl_link_af_alloc(link, &inet_ops)))
                return -NLE_NOMEM;
 
        if (cfgid == 0 || cfgid > IPV4_DEVCONF_MAX)
                return -NLE_RANGE;
 
        id->i_confset[cfgid - 1] = 1;
        id->i_conf[cfgid - 1] = value;
 
        return 0;
}
 
 
static void __init inet_init(void)
{
        rtnl_link_af_register(&inet_ops);
}
 
static void __exit inet_exit(void)
{
        rtnl_link_af_unregister(&inet_ops);
}
 
/** @} */