// SPDX-License-Identifier: GPL-2.0-or-later
/* 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.
 *
 * Please send any bug reports or fixes you make to the
 * email address(es):
 *    lksctp developers <linux-sctp@vger.kernel.org>
 *
 * Written or modified by:
 *    La Monte H.P. Yarroll <piggy@acm.org>
 *    Karl Knutson          <karl@athena.chicago.il.us>
 *    Jon Grimm             <jgrimm@us.ibm.com>
 *    Daisy Chang           <daisyc@us.ibm.com>
 */

#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 *net, struct sctp_bind_addr *dest,
                              union sctp_addr *addr, enum sctp_scope 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,
                        enum sctp_scope 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, sizeof(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)
{
        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);
}

/* 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,
                       int new_size, __u8 addr_state, gfp_t gfp)
{
        struct sctp_sockaddr_entry *addr;

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

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

        /* 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) ||
                    !af->from_addr_param(&addr, rawaddr, htons(port), 0)) {
                        retval = -EINVAL;
                        goto out_err;
                }

                if (sctp_bind_addr_state(bp, &addr) != -1)
                        goto next;
                retval = sctp_add_bind_addr(bp, &addr, sizeof(addr),
                                            SCTP_ADDR_SRC, gfp);
                if (retval)
                        /* Can't finish building the list, clean up. */
                        goto out_err;

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

        return retval;

out_err:
        if (retval)
                sctp_bind_addr_clean(bp);

        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;
}

int sctp_bind_addrs_check(struct sctp_sock *sp,
                          struct sctp_sock *sp2, int cnt2)
{
        struct sctp_bind_addr *bp2 = &sp2->ep->base.bind_addr;
        struct sctp_bind_addr *bp = &sp->ep->base.bind_addr;
        struct sctp_sockaddr_entry *laddr, *laddr2;
        bool exist = false;
        int cnt = 0;

        rcu_read_lock();
        list_for_each_entry_rcu(laddr, &bp->address_list, list) {
                list_for_each_entry_rcu(laddr2, &bp2->address_list, list) {
                        if (sp->pf->af->cmp_addr(&laddr->a, &laddr2->a) &&
                            laddr->valid && laddr2->valid) {
                                exist = true;
                                goto next;
                        }
                }
                cnt = 0;
                break;
next:
                cnt++;
        }
        rcu_read_unlock();

        return (cnt == cnt2) ? 0 : (exist ? -EEXIST : 1);
}

/* 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;

        af = sctp_get_af_specific(addr->sa.sa_family);
        if (unlikely(!af))
                return -1;

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

        return -1;
}

/* 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, enum sctp_scope 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_ALLOWED) &&
                      (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, sizeof(*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,
                  enum sctp_scope scope)
{
        enum sctp_scope 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
         * 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'?  */
enum sctp_scope 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);
}