bind_addr.c

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/* SCTP kernel implementation
 * (C) Copyright IBM Corp. 2001, 2003
 * Copyright (c) Cisco 1999,2000
 * Copyright (c) Motorola 1999,2000,2001
 * Copyright (c) La Monte H.P. Yarroll 2001
 *
 * This file is part of the SCTP kernel implementation.
 *
 * A collection class to handle the storage of transport addresses.
 *
 * This SCTP implementation is free software;
 * you can redistribute it and/or modify it under the terms of
 * the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This SCTP implementation is distributed in the hope that it
 * will be useful, but WITHOUT ANY WARRANTY; without even the implied
 *                 ************************
 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with GNU CC; see the file COPYING.  If not, write to
 * the Free Software Foundation, 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 *
 * Please send any bug reports or fixes you make to the
 * email address(es):
 *    lksctp developers <[email protected]>
 *
 * Or submit a bug report through the following website:
 *    http://www.sf.net/projects/lksctp
 *
 * Written or modified by:
 *    La Monte H.P. Yarroll <[email protected]>
 *    Karl Knutson          <[email protected]>
 *    Jon Grimm             <[email protected]>
 *    Daisy Chang           <[email protected]>
 *
 * Any bugs reported given to us we will try to fix... any fixes shared will
 * be incorporated into the next SCTP release.
 */

#include <linux/types.h>
#include <linux/slab.h>
#include <linux/in.h>
#include <net/sock.h>
#include <net/ipv6.h>
#include <net/if_inet6.h>
#include <net/sctp/sctp.h>
#include <net/sctp/sm.h>

/* Forward declarations for internal helpers. */
static int sctp_copy_one_addr(struct net *, struct sctp_bind_addr *,
                  union sctp_addr *, sctp_scope_t scope, gfp_t gfp,
                  int flags);
static void sctp_bind_addr_clean(struct sctp_bind_addr *);

/* First Level Abstractions. */

/* Copy 'src' to 'dest' taking 'scope' into account.  Omit addresses
 * in 'src' which have a broader scope than 'scope'.
 */
int sctp_bind_addr_copy(struct net *net, struct sctp_bind_addr *dest,
            const struct sctp_bind_addr *src,
            sctp_scope_t scope, gfp_t gfp,
            int flags)
{
    struct sctp_sockaddr_entry *addr;
    int error = 0;

    /* All addresses share the same port.  */
    dest->port = src->port;

    /* Extract the addresses which are relevant for this scope.  */
    list_for_each_entry(addr, &src->address_list, list) {
        error = sctp_copy_one_addr(net, dest, &addr->a, scope,
                       gfp, flags);
        if (error < 0)
            goto out;
    }

    /* If there are no addresses matching the scope and
     * this is global scope, try to get a link scope address, with
     * the assumption that we must be sitting behind a NAT.
     */
    if (list_empty(&dest->address_list) && (SCTP_SCOPE_GLOBAL == scope)) {
        list_for_each_entry(addr, &src->address_list, list) {
            error = sctp_copy_one_addr(net, dest, &addr->a,
                           SCTP_SCOPE_LINK, gfp,
                           flags);
            if (error < 0)
                goto out;
        }
    }

out:
    if (error)
        sctp_bind_addr_clean(dest);

    return error;
}

/* Exactly duplicate the address lists.  This is necessary when doing
 * peer-offs and accepts.  We don't want to put all the current system
 * addresses into the endpoint.  That's useless.  But we do want duplicat
 * the list of bound addresses that the older endpoint used.
 */
int sctp_bind_addr_dup(struct sctp_bind_addr *dest,
            const struct sctp_bind_addr *src,
            gfp_t gfp)
{
    struct sctp_sockaddr_entry *addr;
    int error = 0;

    /* All addresses share the same port.  */
    dest->port = src->port;

    list_for_each_entry(addr, &src->address_list, list) {
        error = sctp_add_bind_addr(dest, &addr->a, 1, gfp);
        if (error < 0)
            break;
    }

    return error;
}

/* Initialize the SCTP_bind_addr structure for either an endpoint or
 * an association.
 */
void sctp_bind_addr_init(struct sctp_bind_addr *bp, __u16 port)
{
    bp->malloced = 0;

    INIT_LIST_HEAD(&bp->address_list);
    bp->port = port;
}

/* Dispose of the address list. */
static void sctp_bind_addr_clean(struct sctp_bind_addr *bp)
{
    struct sctp_sockaddr_entry *addr, *temp;

    /* Empty the bind address list. */
    list_for_each_entry_safe(addr, temp, &bp->address_list, list) {
        list_del_rcu(&addr->list);
        kfree_rcu(addr, rcu);
        SCTP_DBG_OBJCNT_DEC(addr);
    }
}

/* Dispose of an SCTP_bind_addr structure  */
void sctp_bind_addr_free(struct sctp_bind_addr *bp)
{
    /* Empty the bind address list. */
    sctp_bind_addr_clean(bp);

    if (bp->malloced) {
        kfree(bp);
        SCTP_DBG_OBJCNT_DEC(bind_addr);
    }
}

/* Add an address to the bind address list in the SCTP_bind_addr structure. */
int sctp_add_bind_addr(struct sctp_bind_addr *bp, union sctp_addr *new,
               __u8 addr_state, gfp_t gfp)
{
    struct sctp_sockaddr_entry *addr;

    /* Add the address to the bind address list.  */
    addr = t_new(struct sctp_sockaddr_entry, gfp);
    if (!addr)
        return -ENOMEM;

    memcpy(&addr->a, new, sizeof(*new));

    /* Fix up the port if it has not yet been set.
     * Both v4 and v6 have the port at the same offset.
     */
    if (!addr->a.v4.sin_port)
        addr->a.v4.sin_port = htons(bp->port);

    addr->state = addr_state;
    addr->valid = 1;

    INIT_LIST_HEAD(&addr->list);

    /* We always hold a socket lock when calling this function,
     * and that acts as a writer synchronizing lock.
     */
    list_add_tail_rcu(&addr->list, &bp->address_list);
    SCTP_DBG_OBJCNT_INC(addr);

    return 0;
}

/* Delete an address from the bind address list in the SCTP_bind_addr
 * structure.
 */
int sctp_del_bind_addr(struct sctp_bind_addr *bp, union sctp_addr *del_addr)
{
    struct sctp_sockaddr_entry *addr, *temp;
    int found = 0;

    /* We hold the socket lock when calling this function,
     * and that acts as a writer synchronizing lock.
     */
    list_for_each_entry_safe(addr, temp, &bp->address_list, list) {
        if (sctp_cmp_addr_exact(&addr->a, del_addr)) {
            /* Found the exact match. */
            found = 1;
            addr->valid = 0;
            list_del_rcu(&addr->list);
            break;
        }
    }

    if (found) {
        kfree_rcu(addr, rcu);
        SCTP_DBG_OBJCNT_DEC(addr);
        return 0;
    }

    return -EINVAL;
}

/* Create a network byte-order representation of all the addresses
 * formated as SCTP parameters.
 *
 * The second argument is the return value for the length.
 */
union sctp_params sctp_bind_addrs_to_raw(const struct sctp_bind_addr *bp,
                     int *addrs_len,
                     gfp_t gfp)
{
    union sctp_params addrparms;
    union sctp_params retval;
    int addrparms_len;
    union sctp_addr_param rawaddr;
    int len;
    struct sctp_sockaddr_entry *addr;
    struct list_head *pos;
    struct sctp_af *af;

    addrparms_len = 0;
    len = 0;

    /* Allocate enough memory at once. */
    list_for_each(pos, &bp->address_list) {
        len += sizeof(union sctp_addr_param);
    }

    /* Don't even bother embedding an address if there
     * is only one.
     */
    if (len == sizeof(union sctp_addr_param)) {
        retval.v = NULL;
        goto end_raw;
    }

    retval.v = kmalloc(len, gfp);
    if (!retval.v)
        goto end_raw;

    addrparms = retval;

    list_for_each_entry(addr, &bp->address_list, list) {
        af = sctp_get_af_specific(addr->a.v4.sin_family);
        len = af->to_addr_param(&addr->a, &rawaddr);
        memcpy(addrparms.v, &rawaddr, len);
        addrparms.v += len;
        addrparms_len += len;
    }

end_raw:
    *addrs_len = addrparms_len;
    return retval;
}

/*
 * Create an address list out of the raw address list format (IPv4 and IPv6
 * address parameters).
 */
int sctp_raw_to_bind_addrs(struct sctp_bind_addr *bp, __u8 *raw_addr_list,
               int addrs_len, __u16 port, gfp_t gfp)
{
    union sctp_addr_param *rawaddr;
    struct sctp_paramhdr *param;
    union sctp_addr addr;
    int retval = 0;
    int len;
    struct sctp_af *af;

    /* Convert the raw address to standard address format */
    while (addrs_len) {
        param = (struct sctp_paramhdr *)raw_addr_list;
        rawaddr = (union sctp_addr_param *)raw_addr_list;

        af = sctp_get_af_specific(param_type2af(param->type));
        if (unlikely(!af)) {
            retval = -EINVAL;
            sctp_bind_addr_clean(bp);
            break;
        }

        af->from_addr_param(&addr, rawaddr, htons(port), 0);
        retval = sctp_add_bind_addr(bp, &addr, SCTP_ADDR_SRC, gfp);
        if (retval) {
            /* Can't finish building the list, clean up. */
            sctp_bind_addr_clean(bp);
            break;
        }

        len = ntohs(param->length);
        addrs_len -= len;
        raw_addr_list += len;
    }

    return retval;
}

/********************************************************************
 * 2nd Level Abstractions
 ********************************************************************/

/* Does this contain a specified address?  Allow wildcarding. */
int sctp_bind_addr_match(struct sctp_bind_addr *bp,
             const union sctp_addr *addr,
             struct sctp_sock *opt)
{
    struct sctp_sockaddr_entry *laddr;
    int match = 0;

    rcu_read_lock();
    list_for_each_entry_rcu(laddr, &bp->address_list, list) {
        if (!laddr->valid)
            continue;
        if (opt->pf->cmp_addr(&laddr->a, addr, opt)) {
            match = 1;
            break;
        }
    }
    rcu_read_unlock();

    return match;
}

/* Does the address 'addr' conflict with any addresses in
 * the bp.
 */
int sctp_bind_addr_conflict(struct sctp_bind_addr *bp,
                const union sctp_addr *addr,
                struct sctp_sock *bp_sp,
                struct sctp_sock *addr_sp)
{
    struct sctp_sockaddr_entry *laddr;
    int conflict = 0;
    struct sctp_sock *sp;

    /* Pick the IPv6 socket as the basis of comparison
     * since it's usually a superset of the IPv4.
     * If there is no IPv6 socket, then default to bind_addr.
     */
    if (sctp_opt2sk(bp_sp)->sk_family == AF_INET6)
        sp = bp_sp;
    else if (sctp_opt2sk(addr_sp)->sk_family == AF_INET6)
        sp = addr_sp;
    else
        sp = bp_sp;

    rcu_read_lock();
    list_for_each_entry_rcu(laddr, &bp->address_list, list) {
        if (!laddr->valid)
            continue;

        conflict = sp->pf->cmp_addr(&laddr->a, addr, sp);
        if (conflict)
            break;
    }
    rcu_read_unlock();

    return conflict;
}

/* Get the state of the entry in the bind_addr_list */
int sctp_bind_addr_state(const struct sctp_bind_addr *bp,
             const union sctp_addr *addr)
{
    struct sctp_sockaddr_entry *laddr;
    struct sctp_af *af;
    int state = -1;

    af = sctp_get_af_specific(addr->sa.sa_family);
    if (unlikely(!af))
        return state;

    rcu_read_lock();
    list_for_each_entry_rcu(laddr, &bp->address_list, list) {
        if (!laddr->valid)
            continue;
        if (af->cmp_addr(&laddr->a, addr)) {
            state = laddr->state;
            break;
        }
    }
    rcu_read_unlock();

    return state;
}

/* Find the first address in the bind address list that is not present in
 * the addrs packed array.
 */
union sctp_addr *sctp_find_unmatch_addr(struct sctp_bind_addr   *bp,
                    const union sctp_addr   *addrs,
                    int         addrcnt,
                    struct sctp_sock    *opt)
{
    struct sctp_sockaddr_entry  *laddr;
    union sctp_addr         *addr;
    void                *addr_buf;
    struct sctp_af          *af;
    int             i;

    /* This is only called sctp_send_asconf_del_ip() and we hold
     * the socket lock in that code patch, so that address list
     * can't change.
     */
    list_for_each_entry(laddr, &bp->address_list, list) {
        addr_buf = (union sctp_addr *)addrs;
        for (i = 0; i < addrcnt; i++) {
            addr = addr_buf;
            af = sctp_get_af_specific(addr->v4.sin_family);
            if (!af)
                break;

            if (opt->pf->cmp_addr(&laddr->a, addr, opt))
                break;

            addr_buf += af->sockaddr_len;
        }
        if (i == addrcnt)
            return &laddr->a;
    }

    return NULL;
}

/* Copy out addresses from the global local address list. */
static int sctp_copy_one_addr(struct net *net, struct sctp_bind_addr *dest,
                  union sctp_addr *addr,
                  sctp_scope_t scope, gfp_t gfp,
                  int flags)
{
    int error = 0;

    if (sctp_is_any(NULL, addr)) {
        error = sctp_copy_local_addr_list(net, dest, scope, gfp, flags);
    } else if (sctp_in_scope(net, addr, scope)) {
        /* Now that the address is in scope, check to see if
         * the address type is supported by local sock as
         * well as the remote peer.
         */
        if ((((AF_INET == addr->sa.sa_family) &&
              (flags & SCTP_ADDR4_PEERSUPP))) ||
            (((AF_INET6 == addr->sa.sa_family) &&
              (flags & SCTP_ADDR6_ALLOWED) &&
              (flags & SCTP_ADDR6_PEERSUPP))))
            error = sctp_add_bind_addr(dest, addr, SCTP_ADDR_SRC,
                            gfp);
    }

    return error;
}

/* Is this a wildcard address?  */
int sctp_is_any(struct sock *sk, const union sctp_addr *addr)
{
    unsigned short fam = 0;
    struct sctp_af *af;

    /* Try to get the right address family */
    if (addr->sa.sa_family != AF_UNSPEC)
        fam = addr->sa.sa_family;
    else if (sk)
        fam = sk->sk_family;

    af = sctp_get_af_specific(fam);
    if (!af)
        return 0;

    return af->is_any(addr);
}

/* Is 'addr' valid for 'scope'?  */
int sctp_in_scope(struct net *net, const union sctp_addr *addr, sctp_scope_t scope)
{
    sctp_scope_t addr_scope = sctp_scope(addr);

    /* The unusable SCTP addresses will not be considered with
     * any defined scopes.
     */
    if (SCTP_SCOPE_UNUSABLE == addr_scope)
        return 0;
    /*
     * For INIT and INIT-ACK address list, let L be the level of
     * of requested destination address, sender and receiver
     * SHOULD include all of its addresses with level greater
     * than or equal to L.
     *
     * Address scoping can be selectively controlled via sysctl
     * option
     */
    switch (net->sctp.scope_policy) {
    case SCTP_SCOPE_POLICY_DISABLE:
        return 1;
    case SCTP_SCOPE_POLICY_ENABLE:
        if (addr_scope <= scope)
            return 1;
        break;
    case SCTP_SCOPE_POLICY_PRIVATE:
        if (addr_scope <= scope || SCTP_SCOPE_PRIVATE == addr_scope)
            return 1;
        break;
    case SCTP_SCOPE_POLICY_LINK:
        if (addr_scope <= scope || SCTP_SCOPE_LINK == addr_scope)
            return 1;
        break;
    default:
        break;
    }

    return 0;
}

int sctp_is_ep_boundall(struct sock *sk)
{
    struct sctp_bind_addr *bp;
    struct sctp_sockaddr_entry *addr;

    bp = &sctp_sk(sk)->ep->base.bind_addr;
    if (sctp_list_single_entry(&bp->address_list)) {
        addr = list_entry(bp->address_list.next,
                  struct sctp_sockaddr_entry, list);
        if (sctp_is_any(sk, &addr->a))
            return 1;
    }
    return 0;
}

/********************************************************************
 * 3rd Level Abstractions
 ********************************************************************/

/* What is the scope of 'addr'?  */
sctp_scope_t sctp_scope(const union sctp_addr *addr)
{
    struct sctp_af *af;

    af = sctp_get_af_specific(addr->sa.sa_family);
    if (!af)
        return SCTP_SCOPE_UNUSABLE;

    return af->scope((union sctp_addr *)addr);
}