rtnetlink.h

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#ifndef __LINUX_RTNETLINK_H
#define __LINUX_RTNETLINK_H

#ifdef __KERNEL__
#include <linux/config.h>
#endif
#include <linux/netlink.h>

#define RTNL_DEBUG 1


/****
 *              Routing/neighbour discovery messages.
 ****/

/* Types of messages */

#define RTM_BASE        0x10

#define RTM_NEWLINK     (RTM_BASE+0)
#define RTM_DELLINK     (RTM_BASE+1)
#define RTM_GETLINK     (RTM_BASE+2)

#define RTM_NEWADDR     (RTM_BASE+4)
#define RTM_DELADDR     (RTM_BASE+5)
#define RTM_GETADDR     (RTM_BASE+6)

#define RTM_NEWROUTE    (RTM_BASE+8)
#define RTM_DELROUTE    (RTM_BASE+9)
#define RTM_GETROUTE    (RTM_BASE+10)

#define RTM_NEWNEIGH    (RTM_BASE+12)
#define RTM_DELNEIGH    (RTM_BASE+13)
#define RTM_GETNEIGH    (RTM_BASE+14)

#define RTM_NEWRULE     (RTM_BASE+16)
#define RTM_DELRULE     (RTM_BASE+17)
#define RTM_GETRULE     (RTM_BASE+18)

#define RTM_NEWQDISC    (RTM_BASE+20)
#define RTM_DELQDISC    (RTM_BASE+21)
#define RTM_GETQDISC    (RTM_BASE+22)

#define RTM_NEWTCLASS   (RTM_BASE+24)
#define RTM_DELTCLASS   (RTM_BASE+25)
#define RTM_GETTCLASS   (RTM_BASE+26)

#define RTM_NEWTFILTER  (RTM_BASE+28)
#define RTM_DELTFILTER  (RTM_BASE+29)
#define RTM_GETTFILTER  (RTM_BASE+30)

#define RTM_MAX         (RTM_BASE+31)

/* 
   Generic structure for encapsulation optional route information.
   It is reminiscent of sockaddr, but with sa_family replaced
   with attribute type.
 */

struct rtattr
{
        unsigned short  rta_len;
        unsigned short  rta_type;
};

/* Macros to handle rtattributes */

#define RTA_ALIGNTO     4
#define RTA_ALIGN(len) ( ((len)+RTA_ALIGNTO-1) & ~(RTA_ALIGNTO-1) )
#define RTA_OK(rta,len) ((len) > 0 && (rta)->rta_len >= sizeof(struct rtattr) && \
                         (rta)->rta_len <= (len))
#define RTA_NEXT(rta,attrlen)   ((attrlen) -= RTA_ALIGN((rta)->rta_len), \
                                 (struct rtattr*)(((char*)(rta)) + RTA_ALIGN((rta)->rta_len)))
#define RTA_LENGTH(len) (RTA_ALIGN(sizeof(struct rtattr)) + (len))
#define RTA_SPACE(len)  RTA_ALIGN(RTA_LENGTH(len))
#define RTA_DATA(rta)   ((void*)(((char*)(rta)) + RTA_LENGTH(0)))
#define RTA_PAYLOAD(rta) ((int)((rta)->rta_len) - RTA_LENGTH(0))




/******************************************************************************
 *              Definitions used in routing table administation.
 ****/

struct rtmsg
{
        unsigned char           rtm_family;
        unsigned char           rtm_dst_len;
        unsigned char           rtm_src_len;
        unsigned char           rtm_tos;

        unsigned char           rtm_table;      /* Routing table id */
        unsigned char           rtm_protocol;   /* Routing protocol; see below  */
        unsigned char           rtm_scope;      /* See below */ 
        unsigned char           rtm_type;       /* See below    */

        unsigned                rtm_flags;
};

/* rtm_type */

enum
{
        RTN_UNSPEC,
        RTN_UNICAST,            /* Gateway or direct route      */
        RTN_LOCAL,              /* Accept locally               */
        RTN_BROADCAST,          /* Accept locally as broadcast,
                                   send as broadcast */
        RTN_ANYCAST,            /* Accept locally as broadcast,
                                   but send as unicast */
        RTN_MULTICAST,          /* Multicast route              */
        RTN_BLACKHOLE,          /* Drop                         */
        RTN_UNREACHABLE,        /* Destination is unreachable   */
        RTN_PROHIBIT,           /* Administratively prohibited  */
        RTN_THROW,              /* Not in this table            */
        RTN_NAT,                /* Translate this address       */
        RTN_XRESOLVE,           /* Use external resolver        */
};

#define RTN_MAX RTN_XRESOLVE


/* rtm_protocol */

#define RTPROT_UNSPEC   0
#define RTPROT_REDIRECT 1       /* Route installed by ICMP redirects;
                                   not used by current IPv4 */
#define RTPROT_KERNEL   2       /* Route installed by kernel            */
#define RTPROT_BOOT     3       /* Route installed during boot          */
#define RTPROT_STATIC   4       /* Route installed by administrator     */

/* Values of protocol >= RTPROT_STATIC are not interpreted by kernel;
   they just passed from user and back as is.
   It will be used by hypothetical multiple routing daemons.
   Note that protocol values should be standardized in order to
   avoid conflicts.
 */

#define RTPROT_GATED    8       /* Apparently, GateD */
#define RTPROT_RA       9       /* RDISC/ND router advertisments */
#define RTPROT_MRT      10      /* Merit MRT */
#define RTPROT_ZEBRA    11      /* Zebra */
#define RTPROT_BIRD     12      /* BIRD */

/* rtm_scope

   Really it is not scope, but sort of distance to the destination.
   NOWHERE are reserved for not existing destinations, HOST is our
   local addresses, LINK are destinations, located on directly attached
   link and UNIVERSE is everywhere in the Universe.

   Intermediate values are also possible f.e. interior routes
   could be assigned a value between UNIVERSE and LINK.
*/

enum rt_scope_t
{
        RT_SCOPE_UNIVERSE=0,
/* User defined values  */
        RT_SCOPE_SITE=200,
        RT_SCOPE_LINK=253,
        RT_SCOPE_HOST=254,
        RT_SCOPE_NOWHERE=255
};

/* rtm_flags */

#define RTM_F_NOTIFY            0x100   /* Notify user of route change  */
#define RTM_F_CLONED            0x200   /* This route is cloned         */
#define RTM_F_EQUALIZE          0x400   /* Multipath equalizer: NI      */

/* Reserved table identifiers */

enum rt_class_t
{
        RT_TABLE_UNSPEC=0,
/* User defined values */
        RT_TABLE_DEFAULT=253,
        RT_TABLE_MAIN=254,
        RT_TABLE_LOCAL=255
};
#define RT_TABLE_MAX RT_TABLE_LOCAL



/* Routing message attributes */

enum rtattr_type_t
{
        RTA_UNSPEC,
        RTA_DST,
        RTA_SRC,
        RTA_IIF,
        RTA_OIF,
        RTA_GATEWAY,
        RTA_PRIORITY,
        RTA_PREFSRC,
        RTA_METRICS,
        RTA_MULTIPATH,
        RTA_PROTOINFO,
        RTA_FLOW,
        RTA_CACHEINFO
};

#define RTA_MAX RTA_CACHEINFO

#define RTM_RTA(r)  ((struct rtattr*)(((char*)(r)) + NLMSG_ALIGN(sizeof(struct rtmsg))))
#define RTM_PAYLOAD(n) NLMSG_PAYLOAD(n,sizeof(struct rtmsg))

/* RTM_MULTIPATH --- array of struct rtnexthop.
 *
 * "struct rtnexthop" describres all necessary nexthop information,
 * i.e. parameters of path to a destination via this nextop.
 *
 * At the moment it is impossible to set different prefsrc, mtu, window
 * and rtt for different paths from multipath.
 */

struct rtnexthop
{
        unsigned short          rtnh_len;
        unsigned char           rtnh_flags;
        unsigned char           rtnh_hops;
        int                     rtnh_ifindex;
};

/* rtnh_flags */

#define RTNH_F_DEAD             1       /* Nexthop is dead (used by multipath)  */
#define RTNH_F_PERVASIVE        2       /* Do recursive gateway lookup  */
#define RTNH_F_ONLINK           4       /* Gateway is forced on link    */

/* Macros to handle hexthops */

#define RTNH_ALIGNTO    4
#define RTNH_ALIGN(len) ( ((len)+RTNH_ALIGNTO-1) & ~(RTNH_ALIGNTO-1) )
#define RTNH_OK(rtnh,len) ((rtnh)->rtnh_len >= sizeof(struct rtnexthop) && \
                           ((int)(rtnh)->rtnh_len) <= (len))
#define RTNH_NEXT(rtnh) ((struct rtnexthop*)(((char*)(rtnh)) + RTNH_ALIGN((rtnh)->rtnh_len)))
#define RTNH_LENGTH(len) (RTNH_ALIGN(sizeof(struct rtnexthop)) + (len))
#define RTNH_SPACE(len) RTNH_ALIGN(RTNH_LENGTH(len))
#define RTNH_DATA(rtnh)   ((struct rtattr*)(((char*)(rtnh)) + RTNH_LENGTH(0)))

/* RTM_CACHEINFO */

struct rta_cacheinfo
{
        __u32   rta_clntref;
        __u32   rta_lastuse;
        __s32   rta_expires;
        __u32   rta_error;
        __u32   rta_used;
};

/* RTM_METRICS --- array of struct rtattr with types of RTAX_* */

enum
{
        RTAX_UNSPEC,
        RTAX_LOCK,
        RTAX_MTU,
        RTAX_WINDOW,
        RTAX_RTT,
        RTAX_HOPS,
        RTAX_SSTHRESH,
        RTAX_CWND,
};

#define RTAX_MAX RTAX_CWND



/*********************************************************
 *              Interface address.
 ****/

struct ifaddrmsg
{
        unsigned char   ifa_family;
        unsigned char   ifa_prefixlen;  /* The prefix length            */
        unsigned char   ifa_flags;      /* Flags                        */
        unsigned char   ifa_scope;      /* See above                    */
        int             ifa_index;      /* Link index                   */
};

enum
{
        IFA_UNSPEC,
        IFA_ADDRESS,
        IFA_LOCAL,
        IFA_LABEL,
        IFA_BROADCAST,
        IFA_ANYCAST,
        IFA_CACHEINFO
};

#define IFA_MAX IFA_CACHEINFO

/* ifa_flags */

#define IFA_F_SECONDARY         0x01

#define IFA_F_DEPRECATED        0x20
#define IFA_F_TENTATIVE         0x40
#define IFA_F_PERMANENT         0x80

struct ifa_cacheinfo
{
        __s32   ifa_prefered;
        __s32   ifa_valid;
};


#define IFA_RTA(r)  ((struct rtattr*)(((char*)(r)) + NLMSG_ALIGN(sizeof(struct ifaddrmsg))))
#define IFA_PAYLOAD(n) NLMSG_PAYLOAD(n,sizeof(struct ifaddrmsg))

/*
   Important comment:
   IFA_ADDRESS is prefix address, rather than local interface address.
   It makes no difference for normally configured broadcast interfaces,
   but for point-to-point IFA_ADDRESS is DESTINATION address,
   local address is supplied in IFA_LOCAL attribute.
 */

/**************************************************************
 *              Neighbour discovery.
 ****/

struct ndmsg
{
        unsigned char   ndm_family;
        unsigned char   ndm_pad1;
        unsigned short  ndm_pad2;
        int             ndm_ifindex;    /* Link index                   */
        __u16           ndm_state;
        __u8            ndm_flags;
        __u8            ndm_type;
};

enum
{
        NDA_UNSPEC,
        NDA_DST,
        NDA_LLADDR,
        NDA_CACHEINFO
};

#define NDA_MAX NDA_CACHEINFO

#define NDA_RTA(r)  ((struct rtattr*)(((char*)(r)) + NLMSG_ALIGN(sizeof(struct ndmsg))))
#define NDA_PAYLOAD(n) NLMSG_PAYLOAD(n,sizeof(struct ndmsg))

/*
 *      Neighbor Cache Entry Flags
 */

#define NTF_PROXY       0x08    /* == ATF_PUBL */
#define NTF_ROUTER      0x80

/*
 *      Neighbor Cache Entry States.
 */

#define NUD_INCOMPLETE  0x01
#define NUD_REACHABLE   0x02
#define NUD_STALE       0x04
#define NUD_DELAY       0x08
#define NUD_PROBE       0x10
#define NUD_FAILED      0x20

/* Dummy states */
#define NUD_NOARP       0x40
#define NUD_PERMANENT   0x80
#define NUD_NONE        0x00


struct nda_cacheinfo
{
        __u32           ndm_confirmed;
        __u32           ndm_used;
        __u32           ndm_updated;
        __u32           ndm_refcnt;
};

/****
 *              General form of address family dependent message.
 ****/

struct rtgenmsg
{
        unsigned char           rtgen_family;
};

/*****************************************************************
 *              Link layer specific messages.
 ****/

/* struct ifinfomsg
 * passes link level specific information, not dependent
 * on network protocol.
 */

struct ifinfomsg
{
        unsigned char   ifi_family;
        unsigned char   __ifi_pad;
        unsigned short  ifi_type;               /* ARPHRD_* */
        int             ifi_index;              /* Link index   */
        unsigned        ifi_flags;              /* IFF_* flags  */
        unsigned        ifi_change;             /* IFF_* change mask */
};

enum
{
        IFLA_UNSPEC,
        IFLA_ADDRESS,
        IFLA_BROADCAST,
        IFLA_IFNAME,
        IFLA_MTU,
        IFLA_LINK,
        IFLA_QDISC,
        IFLA_STATS
};


#define IFLA_MAX IFLA_STATS

#define IFLA_RTA(r)  ((struct rtattr*)(((char*)(r)) + NLMSG_ALIGN(sizeof(struct ifinfomsg))))
#define IFLA_PAYLOAD(n) NLMSG_PAYLOAD(n,sizeof(struct ifinfomsg))

/* ifi_flags.

   IFF_* flags.

   The only change is:
   IFF_LOOPBACK, IFF_BROADCAST and IFF_POINTOPOINT are
   more not changeable by user. They describe link media
   characteristics and set by device driver.

   Comments:
   - Combination IFF_BROADCAST|IFF_POINTOPOINT is invalid
   - If neiher of these three flags are set;
     the interface is NBMA.

   - IFF_MULTICAST does not mean anything special:
   multicasts can be used on all not-NBMA links.
   IFF_MULTICAST means that this media uses special encapsulation
   for multicast frames. Apparently, all IFF_POINTOPOINT and
   IFF_BROADCAST devices are able to use multicasts too.
 */

/* ifi_link.
   For usual devices it is equal ifi_index.
   If it is a "virtual interface" (f.e. tunnel), ifi_link
   can point to real physical interface (f.e. for bandwidth calculations),
   or maybe 0, what means, that real media is unknown (usual
   for IPIP tunnels, when route to endpoint is allowed to change)
 */

/*****************************************************************
 *              Traffic control messages.
 ****/

struct tcmsg
{
        unsigned char   tcm_family;
        unsigned char   tcm__pad1;
        unsigned short  tcm__pad2;
        int             tcm_ifindex;
        __u32           tcm_handle;
        __u32           tcm_parent;
        __u32           tcm_info;
};

enum
{
        TCA_UNSPEC,
        TCA_KIND,
        TCA_OPTIONS,
        TCA_STATS,
        TCA_XSTATS,
        TCA_RATE,
};

#define TCA_MAX TCA_RATE

#define TCA_RTA(r)  ((struct rtattr*)(((char*)(r)) + NLMSG_ALIGN(sizeof(struct tcmsg))))
#define TCA_PAYLOAD(n) NLMSG_PAYLOAD(n,sizeof(struct tcmsg))


/* SUMMARY: maximal rtattr understood by kernel */

#define RTATTR_MAX              RTA_MAX

/* RTnetlink multicast groups */

#define RTMGRP_LINK             1
#define RTMGRP_NOTIFY           2
#define RTMGRP_NEIGH            4
#define RTMGRP_TC               8

#define RTMGRP_IPV4_IFADDR      0x10
#define RTMGRP_IPV4_MROUTE      0x20
#define RTMGRP_IPV4_ROUTE       0x40

#define RTMGRP_IPV6_IFADDR      0x100
#define RTMGRP_IPV6_MROUTE      0x200
#define RTMGRP_IPV6_ROUTE       0x400

/* End of information exported to user level */

#ifdef __KERNEL__

extern atomic_t rtnl_rlockct;
extern struct wait_queue *rtnl_wait;

extern __inline__ int rtattr_strcmp(struct rtattr *rta, char *str)
{
        int len = strlen(str) + 1;
        return len > rta->rta_len || memcmp(RTA_DATA(rta), str, len);
}

extern int rtattr_parse(struct rtattr *tb[], int maxattr, struct rtattr *rta, int len);

#ifdef CONFIG_RTNETLINK
extern struct sock *rtnl;

struct rtnetlink_link
{
        int (*doit)(struct sk_buff *, struct nlmsghdr*, void *attr);
        int (*dumpit)(struct sk_buff *, struct netlink_callback *cb);
};

extern struct rtnetlink_link * rtnetlink_links[NPROTO];
extern int rtnetlink_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb);
extern int rtnetlink_send(struct sk_buff *skb, u32 pid, u32 group, int echo);

extern void __rta_fill(struct sk_buff *skb, int attrtype, int attrlen, const void *data);

#define RTA_PUT(skb, attrtype, attrlen, data) \
({ if (skb_tailroom(skb) < (int)RTA_SPACE(attrlen)) goto rtattr_failure; \
   __rta_fill(skb, attrtype, attrlen, data); })

extern unsigned long rtnl_wlockct;

/* NOTE: these locks are not interrupt safe, are not SMP safe,
 * they are even not atomic. 8)8)8) ... and it is not a bug.
 * Really, if these locks will be programmed correctly,
 * all the addressing/routing machine would become SMP safe,
 * but is absolutely useless at the moment, because all the kernel
 * is not reenterable in any case. --ANK
 *
 * Well, atomic_* and set_bit provide the only thing here:
 * gcc is confused not to overoptimize them, that's all.
 * I remember as gcc splitted ++ operation, but cannot reproduce
 * it with gcc-2.7.*. --ANK
 *
 * One more note: rwlock facility should be written and put
 * to a kernel wide location: f.e. current implementation of semaphores
 * (especially, for x86) looks like a wonder. It would be good
 * to have something similar for rwlock. Recursive lock could be also
 * useful thing. --ANK
 */

extern __inline__ int rtnl_shlock_nowait(void)
{
        atomic_inc(&rtnl_rlockct);
        if (test_bit(0, &rtnl_wlockct)) {
                atomic_dec(&rtnl_rlockct);
                return -EAGAIN;
        }
        return 0;
}

extern __inline__ void rtnl_shlock(void)
{
        while (rtnl_shlock_nowait())
                sleep_on(&rtnl_wait);
}

/* Check for possibility to PROMOTE shared lock to exclusive.
   Shared lock must be already grabbed with rtnl_shlock*().
 */

extern __inline__ int rtnl_exlock_nowait(void)
{
        if (atomic_read(&rtnl_rlockct) > 1)
                return -EAGAIN;
        if (test_and_set_bit(0, &rtnl_wlockct))
                return -EAGAIN;
        return 0;
}

extern __inline__ void rtnl_exlock(void)
{
        while (rtnl_exlock_nowait())
                sleep_on(&rtnl_wait);
}

#if 0
extern __inline__ void rtnl_shunlock(void)
{
        atomic_dec(&rtnl_rlockct);
        if (atomic_read(&rtnl_rlockct) <= 1) {
                wake_up(&rtnl_wait);
                if (rtnl && rtnl->receive_queue.qlen)
                        rtnl->data_ready(rtnl, 0);
        }
}
#else

/* The problem: inline requires to include <net/sock.h> and, hence,
   almost all of net includes :-(
 */

#define rtnl_shunlock() ({ \
        atomic_dec(&rtnl_rlockct); \
        if (atomic_read(&rtnl_rlockct) <= 1) { \
                wake_up(&rtnl_wait); \
                if (rtnl && rtnl->receive_queue.qlen) \
                        rtnl->data_ready(rtnl, 0); \
        } \
})
#endif

/* Release exclusive lock. Note, that we do not wake up rtnetlink socket,
 * it will be done later after releasing shared lock.
 */

extern __inline__ void rtnl_exunlock(void)
{
        clear_bit(0, &rtnl_wlockct);
        wake_up(&rtnl_wait);
}

#else

extern __inline__ void rtnl_shlock(void)
{
        while (atomic_read(&rtnl_rlockct))
                sleep_on(&rtnl_wait);
        atomic_inc(&rtnl_rlockct);
}

extern __inline__ void rtnl_shunlock(void)
{
        if (atomic_dec_and_test(&rtnl_rlockct))
                wake_up(&rtnl_wait);
}

extern __inline__ void rtnl_exlock(void)
{
}

extern __inline__ void rtnl_exunlock(void)
{
}

#endif

extern void rtnl_lock(void);
extern void rtnl_unlock(void);
extern void rtnetlink_init(void);

#endif /* __KERNEL__ */


#endif  /* __LINUX_RTNETLINK_H */

---