cls.c

/* SPDX-License-Identifier: LGPL-2.1-only */
/*
 * Copyright (c) 2003-2013 Thomas Graf <tgraf@suug.ch>
 */
 
/**
 * @ingroup tc
 * @defgroup cls Classifiers
 * @{
 */
 
#include <netlink-private/netlink.h>
#include <netlink-private/tc.h>
#include <netlink/netlink.h>
#include <netlink/utils.h>
#include <netlink-private/route/tc-api.h>
#include <netlink/route/classifier.h>
#include <netlink/route/link.h>
 
/** @cond SKIP */
#define CLS_ATTR_PRIO           (TCA_ATTR_MAX << 1)
#define CLS_ATTR_PROTOCOL       (TCA_ATTR_MAX << 2)
/** @endcond */
 
static struct nl_object_ops cls_obj_ops;
static struct nl_cache_ops rtnl_cls_ops;
 
 
static int cls_build(struct rtnl_cls *cls, int type, int flags,
                     struct nl_msg **result)
{
        int err, prio, proto;
        struct tcmsg *tchdr;
        uint32_t required = TCA_ATTR_IFINDEX;
 
        if ((cls->ce_mask & required) != required) {
                APPBUG("ifindex must be specified");
                return -NLE_MISSING_ATTR;
        }
 
        err = rtnl_tc_msg_build(TC_CAST(cls), type, flags, result);
        if (err < 0)
                return err;
 
        tchdr = nlmsg_data(nlmsg_hdr(*result));
        prio = rtnl_cls_get_prio(cls);
        proto = rtnl_cls_get_protocol(cls);
        tchdr->tcm_info = TC_H_MAKE(prio << 16, htons(proto));
 
        return 0;
}
 
/**
 * @name Allocation/Freeing
 * @{
 */
 
struct rtnl_cls *rtnl_cls_alloc(void)
{
        struct rtnl_tc *tc;
 
        tc = TC_CAST(nl_object_alloc(&cls_obj_ops));
        if (tc)
                tc->tc_type = RTNL_TC_TYPE_CLS;
 
        return (struct rtnl_cls *) tc;
}
 
void rtnl_cls_put(struct rtnl_cls *cls)
{
        nl_object_put((struct nl_object *) cls);
}
 
/** @} */
 
/**
 * @name Attributes
 * @{
 */
 
void rtnl_cls_set_prio(struct rtnl_cls *cls, uint16_t prio)
{
        cls->c_prio = prio;
        cls->ce_mask |= CLS_ATTR_PRIO;
}
 
uint16_t rtnl_cls_get_prio(struct rtnl_cls *cls)
{
        if (cls->ce_mask & CLS_ATTR_PRIO)
                return cls->c_prio;
        else
                return 0;
}
 
void rtnl_cls_set_protocol(struct rtnl_cls *cls, uint16_t protocol)
{
        cls->c_protocol = protocol;
        cls->ce_mask |= CLS_ATTR_PROTOCOL;
}
 
uint16_t rtnl_cls_get_protocol(struct rtnl_cls *cls)
{
        if (cls->ce_mask & CLS_ATTR_PROTOCOL)
                return cls->c_protocol;
        else
                return ETH_P_ALL;
}
 
/** @} */
 
 
/**
 * @name Addition/Modification/Deletion
 * @{
 */
 
/**
 * Build a netlink message requesting the addition of a classifier
 * @arg cls             Classifier to add 
 * @arg flags           Additional netlink message flags
 * @arg result          Pointer to store resulting netlink message
 *
 * The behaviour of this function is identical to rtnl_cls_add() with
 * the exception that it will not send the message but return it int the
 * provided return pointer instead.
 *
 * @see rtnl_cls_add()
 *
 * @return 0 on success or a negative error code.
 */
int rtnl_cls_build_add_request(struct rtnl_cls *cls, int flags,
                               struct nl_msg **result)
{
        if (!(flags & NLM_F_CREATE) && !(cls->ce_mask & CLS_ATTR_PRIO)) {
                APPBUG("prio must be specified if not a new classifier");
                return -NLE_MISSING_ATTR;
        }
 
        return cls_build(cls, RTM_NEWTFILTER, flags, result);
}
 
/**
 * Add/Update classifier
 * @arg sk              Netlink socket
 * @arg cls             Classifier to add/update
 * @arg flags           Additional netlink message flags
 *
 * Builds a \c RTM_NEWTFILTER netlink message requesting the addition
 * of a new classifier and sends the message to the kernel. The
 * configuration of the classifier is derived from the attributes of
 * the specified traffic class.
 *
 * The following flags may be specified:
 *  - \c NLM_F_CREATE:  Create classifier if it does not exist,
 *                      otherwise -NLE_OBJ_NOTFOUND is returned.
 *  - \c NLM_F_EXCL:    Return -NLE_EXISTS if a classifier with
 *                      matching handle exists already.
 *
 * Existing classifiers with matching handles will be updated, unless
 * the flag \c NLM_F_EXCL is specified. If no matching classifier
 * exists, it will be created if the flag \c NLM_F_CREATE is set,
 * otherwise the error -NLE_OBJ_NOTFOUND is returned. 
 *
 * If the parent qdisc does not support classes, the error
 * \c NLE_OPNOTSUPP is returned.
 *
 * After sending, the function will wait for the ACK or an eventual
 * error message to be received and will therefore block until the
 * operation has been completed.
 *
 * @note Disabling auto-ack (nl_socket_disable_auto_ack()) will cause
 *       this function to return immediately after sending. In this case,
 *       it is the responsibility of the caller to handle any error
 *       messages returned.
 *
 * @return 0 on success or a negative error code.
 */
int rtnl_cls_add(struct nl_sock *sk, struct rtnl_cls *cls, int flags)
{
        struct nl_msg *msg;
        int err;
        
        if ((err = rtnl_cls_build_add_request(cls, flags, &msg)) < 0)
                return err;
 
        return nl_send_sync(sk, msg);
}
 
/**
 * Build a netlink message to change classifier attributes
 * @arg cls             classifier to change
 * @arg flags           additional netlink message flags
 * @arg result          Pointer to store resulting message.
 *
 * 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 0 on success or a negative error code.
 */
int rtnl_cls_build_change_request(struct rtnl_cls *cls, int flags,
                                  struct nl_msg **result)
{
        return cls_build(cls, RTM_NEWTFILTER, NLM_F_REPLACE | flags, result);
}
 
/**
 * Change a classifier
 * @arg sk              Netlink socket.
 * @arg cls             classifier to change
 * @arg flags           additional netlink message flags
 *
 * Builds a netlink message by calling rtnl_cls_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 processed.
 *
 * @return 0 on success or a negative error if an error occured.
 */
int rtnl_cls_change(struct nl_sock *sk, struct rtnl_cls *cls, int flags)
{
        struct nl_msg *msg;
        int err;
        
        if ((err = rtnl_cls_build_change_request(cls, flags, &msg)) < 0)
                return err;
        
        return nl_send_sync(sk, msg);
}
 
/**
 * Build netlink message requesting the deletion of a classifier
 * @arg cls             Classifier to delete
 * @arg flags           Additional netlink message flags
 * @arg result          Pointer to store resulting netlink message
 *
 * The behaviour of this function is identical to rtnl_cls_delete() with
 * the exception that it will not send the message but return it in the
 * provided return pointer instead.
 *
 * @see rtnl_cls_delete()
 *
 * @return 0 on success or a negative error code.
 */
int rtnl_cls_build_delete_request(struct rtnl_cls *cls, int flags,
                                  struct nl_msg **result)
{
        uint32_t required = CLS_ATTR_PRIO;
 
        if ((cls->ce_mask & required) != required) {
                APPBUG("prio must be specified");
                return -NLE_MISSING_ATTR;
        }
 
        return cls_build(cls, RTM_DELTFILTER, flags, result);
}
 
/**
 * Delete classifier
 * @arg sk              Netlink socket
 * @arg cls             Classifier to delete
 * @arg flags           Additional netlink message flags
 *
 * Builds a \c RTM_DELTFILTER netlink message requesting the deletion
 * of a classifier and sends the message to the kernel.
 *
 * The message is constructed out of the following attributes:
 * - \c ifindex (required)
 * - \c prio (required)
 * - \c protocol (required)
 * - \c handle (required)
 * - \c parent (optional, if not specified parent equals root-qdisc)
 * - \c kind (optional, must match if provided)
 *
 * All other classifier attributes including all class type specific
 * attributes are ignored.
 *
 * After sending, the function will wait for the ACK or an eventual
 * error message to be received and will therefore block until the
 * operation has been completed.
 *
 * @note Disabling auto-ack (nl_socket_disable_auto_ack()) will cause
 *       this function to return immediately after sending. In this case,
 *       it is the responsibility of the caller to handle any error
 *       messages returned.
 *
 * @return 0 on success or a negative error code.
 */
int rtnl_cls_delete(struct nl_sock *sk, struct rtnl_cls *cls, int flags)
{
        struct nl_msg *msg;
        int err;
        
        if ((err = rtnl_cls_build_delete_request(cls, flags, &msg)) < 0)
                return err;
        
        return nl_send_sync(sk, msg);
}
 
/** @} */
 
/**
 * @name Cache Related Functions
 * @{
 */
 
/**
 * Allocate a cache and fill it with all configured classifiers
 * @arg sk              Netlink socket
 * @arg ifindex         Interface index of the network device
 * @arg parent          Parent qdisc/traffic class class
 * @arg result          Pointer to store the created cache
 *
 * Allocates a new classifier cache and fills it with a list of all
 * configured classifier attached to the specified parent qdisc/traffic
 * class on the specified network device. Release the cache with
 * nl_cache_free().
 *
 * @return 0 on success or a negative error code.
 */
int rtnl_cls_alloc_cache(struct nl_sock *sk, int ifindex, uint32_t parent,
                         struct nl_cache **result)
{
        struct nl_cache * cache;
        int err;
        
        if (!(cache = nl_cache_alloc(&rtnl_cls_ops)))
                return -NLE_NOMEM;
 
        cache->c_iarg1 = ifindex;
        cache->c_iarg2 = parent;
        
        if (sk && (err = nl_cache_refill(sk, cache)) < 0) {
                nl_cache_free(cache);
                return err;
        }
 
        *result = cache;
        return 0;
}
 
/**
 * Set interface index and parent handle for classifier cache.
 * @arg cache           Pointer to cache
 * @arg parent          Parent qdisc/traffic class class
 *
 * Set the interface index and parent handle of a classifier cache.
 * This is useful for reusing some existed classifier cache to reduce
 * the overhead introduced by memory allocation.
 *
 * @return void.
 */
void rtnl_cls_cache_set_tc_params(struct nl_cache *cache,
                                  int ifindex, uint32_t parent)
{
        cache->c_iarg1 = ifindex;
        cache->c_iarg2 = parent;
}
 
/**
 * Search classifier by interface index, parent and handle
 * @arg cache           Classifier cache
 * @arg ifindex         Interface index
 * @arg parent          Parent
 * @arg handle          Handle
 *
 * Searches a classifier cache previously allocated with rtnl_cls_alloc_cache()
 * and searches for a classifier matching the interface index, parent
 * and handle.
 *
 * The reference counter is incremented before returning the classifier,
 * therefore the reference must be given back with rtnl_cls_put() after usage.
 *
 * @return Classifier or NULL if no match was found.
 */
struct rtnl_cls *rtnl_cls_find_by_handle(struct nl_cache *cache, int ifindex, uint32_t parent,
                                         uint32_t handle)
{
        struct rtnl_cls *cls;
 
        if (cache->c_ops != &rtnl_cls_ops)
                return NULL;
 
        nl_list_for_each_entry(cls, &cache->c_items, ce_list) {
                if ((cls->c_parent == parent) &&
                    (cls->c_ifindex == ifindex)&&
                    (cls->c_handle == handle)) {
                        nl_object_get((struct nl_object *) cls);
                        return cls;
                }
        }
 
        return NULL;
}
 
/**
 * Search classifier by interface index, parent and priority
 * @arg cache           Classifier cache
 * @arg ifindex         Interface index
 * @arg parent          Parent
 * @arg prio            Priority
 *
 * Searches a classifier cache previously allocated with rtnl_cls_alloc_cache()
 * and searches for a classifier matching the interface index, parent
 * and prio.
 *
 * The reference counter is incremented before returning the classifier,
 * therefore the reference must be given back with rtnl_cls_put() after usage.
 *
 * @return Classifier or NULL if no match was found.
 */
struct rtnl_cls *rtnl_cls_find_by_prio(struct nl_cache *cache, int ifindex,
                                       uint32_t parent, uint16_t prio)
{
        struct rtnl_cls *cls;
 
        if (cache->c_ops != &rtnl_cls_ops)
                return NULL;
 
        nl_list_for_each_entry(cls, &cache->c_items, ce_list) {
                if ((cls->c_parent == parent) &&
                    (cls->c_ifindex == ifindex) &&
                    (cls->c_prio == prio)) {
                        nl_object_get((struct nl_object *) cls);
                        return cls;
                }
        }
 
        return NULL;
}
 
/** @} */
 
static void cls_dump_line(struct rtnl_tc *tc, struct nl_dump_params *p)
{
        struct rtnl_cls *cls = (struct rtnl_cls *) tc;
        char buf[32];
 
        nl_dump(p, " prio %u protocol %s", cls->c_prio,
                nl_ether_proto2str(cls->c_protocol, buf, sizeof(buf)));
}
 
static int cls_msg_parser(struct nl_cache_ops *ops, struct sockaddr_nl *who,
                          struct nlmsghdr *nlh, struct nl_parser_param *pp)
{
        struct rtnl_cls *cls;
        int err;
 
        if (!(cls = rtnl_cls_alloc()))
                return -NLE_NOMEM;
 
        if ((err = rtnl_tc_msg_parse(nlh, TC_CAST(cls))) < 0)
                goto errout;
 
        cls->c_prio = TC_H_MAJ(cls->c_info) >> 16;
        if (cls->c_prio)
                cls->ce_mask |= CLS_ATTR_PRIO;
        cls->c_protocol = ntohs(TC_H_MIN(cls->c_info));
        if (cls->c_protocol)
                cls->ce_mask |= CLS_ATTR_PROTOCOL;
 
        err = pp->pp_cb(OBJ_CAST(cls), pp);
errout:
        rtnl_cls_put(cls);
 
        return err;
}
 
static int cls_request_update(struct nl_cache *cache, struct nl_sock *sk)
{
        struct tcmsg tchdr = {
                .tcm_family = AF_UNSPEC,
                .tcm_ifindex = cache->c_iarg1,
                .tcm_parent = cache->c_iarg2,
        };
 
        return nl_send_simple(sk, RTM_GETTFILTER, NLM_F_DUMP, &tchdr,
                              sizeof(tchdr));
}
 
static struct rtnl_tc_type_ops cls_ops = {
        .tt_type                = RTNL_TC_TYPE_CLS,
        .tt_dump_prefix         = "cls",
        .tt_dump = {
                [NL_DUMP_LINE]  = cls_dump_line,
        },
};
 
static struct nl_cache_ops rtnl_cls_ops = {
        .co_name                = "route/cls",
        .co_hdrsize             = sizeof(struct tcmsg),
        .co_msgtypes            = {
                                        { RTM_NEWTFILTER, NL_ACT_NEW, "new" },
                                        { RTM_DELTFILTER, NL_ACT_DEL, "del" },
                                        { RTM_GETTFILTER, NL_ACT_GET, "get" },
                                        END_OF_MSGTYPES_LIST,
                                  },
        .co_protocol            = NETLINK_ROUTE,
        .co_groups              = tc_groups,
        .co_request_update      = cls_request_update,
        .co_msg_parser          = cls_msg_parser,
        .co_obj_ops             = &cls_obj_ops,
};
 
static struct nl_object_ops cls_obj_ops = {
        .oo_name                = "route/cls",
        .oo_size                = sizeof(struct rtnl_cls),
        .oo_free_data           = rtnl_tc_free_data,
        .oo_clone               = rtnl_tc_clone,
        .oo_dump = {
            [NL_DUMP_LINE]      = rtnl_tc_dump_line,
            [NL_DUMP_DETAILS]   = rtnl_tc_dump_details,
            [NL_DUMP_STATS]     = rtnl_tc_dump_stats,
        },
        .oo_compare             = rtnl_tc_compare,
        .oo_id_attrs            = (TCA_ATTR_IFINDEX | TCA_ATTR_HANDLE),
};
 
static void __init cls_init(void)
{
        rtnl_tc_type_register(&cls_ops);
        nl_cache_mngt_register(&rtnl_cls_ops);
}
 
static void __exit cls_exit(void)
{
        nl_cache_mngt_unregister(&rtnl_cls_ops);
        rtnl_tc_type_unregister(&cls_ops);
}
 
/** @} */