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root/net/ipv6/datagram.c

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DEFINITIONS

This source file includes following definitions.
  1. ip6_datagram_connect
  2. ipv6_icmp_error
  3. ipv6_local_error
  4. ipv6_recv_error
  5. datagram_recv_ctl
  6. datagram_send_ctl

/*
 *      common UDP/RAW code
 *      Linux INET6 implementation
 *
 *      Authors:
 *      Pedro Roque             <roque@di.fc.ul.pt>
 *
 *      This program 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 of the License, or (at your option) any later version.
 */

#include <linux/capability.h>
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/interrupt.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/in6.h>
#include <linux/ipv6.h>
#include <linux/route.h>

#include <net/ipv6.h>
#include <net/ndisc.h>
#include <net/addrconf.h>
#include <net/transp_v6.h>
#include <net/ip6_route.h>
#include <net/tcp_states.h>

#include <linux/errqueue.h>
#include <asm/uaccess.h>

int ip6_datagram_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
{
        struct sockaddr_in6     *usin = (struct sockaddr_in6 *) uaddr;
        struct inet_sock        *inet = inet_sk(sk);
        struct ipv6_pinfo       *np = inet6_sk(sk);
        struct in6_addr         *daddr, *final_p = NULL, final;
        struct dst_entry        *dst;
        struct flowi            fl;
        struct ip6_flowlabel    *flowlabel = NULL;
        int                     addr_type;
        int                     err;

        if (usin->sin6_family == AF_INET) {
                if (__ipv6_only_sock(sk))
                        return -EAFNOSUPPORT;
                err = ip4_datagram_connect(sk, uaddr, addr_len);
                goto ipv4_connected;
        }

        if (addr_len < SIN6_LEN_RFC2133)
                return -EINVAL;

        if (usin->sin6_family != AF_INET6)
                return -EAFNOSUPPORT;

        memset(&fl, 0, sizeof(fl));
        if (np->sndflow) {
                fl.fl6_flowlabel = usin->sin6_flowinfo&IPV6_FLOWINFO_MASK;
                if (fl.fl6_flowlabel&IPV6_FLOWLABEL_MASK) {
                        flowlabel = fl6_sock_lookup(sk, fl.fl6_flowlabel);
                        if (flowlabel == NULL)
                                return -EINVAL;
                        ipv6_addr_copy(&usin->sin6_addr, &flowlabel->dst);
                }
        }

        addr_type = ipv6_addr_type(&usin->sin6_addr);

        if (addr_type == IPV6_ADDR_ANY) {
                /*
                 *      connect to self
                 */
                usin->sin6_addr.s6_addr[15] = 0x01;
        }

        daddr = &usin->sin6_addr;

        if (addr_type == IPV6_ADDR_MAPPED) {
                struct sockaddr_in sin;

                if (__ipv6_only_sock(sk)) {
                        err = -ENETUNREACH;
                        goto out;
                }
                sin.sin_family = AF_INET;
                sin.sin_addr.s_addr = daddr->s6_addr32[3];
                sin.sin_port = usin->sin6_port;

                err = ip4_datagram_connect(sk,
                                           (struct sockaddr*) &sin,
                                           sizeof(sin));

ipv4_connected:
                if (err)
                        goto out;

                ipv6_addr_set(&np->daddr, 0, 0, htonl(0x0000ffff), inet->daddr);

                if (ipv6_addr_any(&np->saddr)) {
                        ipv6_addr_set(&np->saddr, 0, 0, htonl(0x0000ffff),
                                      inet->saddr);
                }

                if (ipv6_addr_any(&np->rcv_saddr)) {
                        ipv6_addr_set(&np->rcv_saddr, 0, 0, htonl(0x0000ffff),
                                      inet->rcv_saddr);
                }
                goto out;
        }

        if (addr_type&IPV6_ADDR_LINKLOCAL) {
                if (addr_len >= sizeof(struct sockaddr_in6) &&
                    usin->sin6_scope_id) {
                        if (sk->sk_bound_dev_if &&
                            sk->sk_bound_dev_if != usin->sin6_scope_id) {
                                err = -EINVAL;
                                goto out;
                        }
                        sk->sk_bound_dev_if = usin->sin6_scope_id;
                }

                if (!sk->sk_bound_dev_if && (addr_type & IPV6_ADDR_MULTICAST))
                        sk->sk_bound_dev_if = np->mcast_oif;

                /* Connect to link-local address requires an interface */
                if (!sk->sk_bound_dev_if) {
                        err = -EINVAL;
                        goto out;
                }
        }

        ipv6_addr_copy(&np->daddr, daddr);
        np->flow_label = fl.fl6_flowlabel;

        inet->dport = usin->sin6_port;

        /*
         *      Check for a route to destination an obtain the
         *      destination cache for it.
         */

        fl.proto = sk->sk_protocol;
        ipv6_addr_copy(&fl.fl6_dst, &np->daddr);
        ipv6_addr_copy(&fl.fl6_src, &np->saddr);
        fl.oif = sk->sk_bound_dev_if;
        fl.fl_ip_dport = inet->dport;
        fl.fl_ip_sport = inet->sport;

        if (!fl.oif && (addr_type&IPV6_ADDR_MULTICAST))
                fl.oif = np->mcast_oif;

        security_sk_classify_flow(sk, &fl);

        if (flowlabel) {
                if (flowlabel->opt && flowlabel->opt->srcrt) {
                        struct rt0_hdr *rt0 = (struct rt0_hdr *) flowlabel->opt->srcrt;
                        ipv6_addr_copy(&final, &fl.fl6_dst);
                        ipv6_addr_copy(&fl.fl6_dst, rt0->addr);
                        final_p = &final;
                }
        } else if (np->opt && np->opt->srcrt) {
                struct rt0_hdr *rt0 = (struct rt0_hdr *)np->opt->srcrt;
                ipv6_addr_copy(&final, &fl.fl6_dst);
                ipv6_addr_copy(&fl.fl6_dst, rt0->addr);
                final_p = &final;
        }

        err = ip6_dst_lookup(sk, &dst, &fl);
        if (err)
                goto out;
        if (final_p)
                ipv6_addr_copy(&fl.fl6_dst, final_p);

        if ((err = __xfrm_lookup(&dst, &fl, sk, XFRM_LOOKUP_WAIT)) < 0) {
                if (err == -EREMOTE)
                        err = ip6_dst_blackhole(sk, &dst, &fl);
                if (err < 0)
                        goto out;
        }

        /* source address lookup done in ip6_dst_lookup */

        if (ipv6_addr_any(&np->saddr))
                ipv6_addr_copy(&np->saddr, &fl.fl6_src);

        if (ipv6_addr_any(&np->rcv_saddr)) {
                ipv6_addr_copy(&np->rcv_saddr, &fl.fl6_src);
                inet->rcv_saddr = LOOPBACK4_IPV6;
        }

        ip6_dst_store(sk, dst,
                      ipv6_addr_equal(&fl.fl6_dst, &np->daddr) ?
                      &np->daddr : NULL,
#ifdef CONFIG_IPV6_SUBTREES
                      ipv6_addr_equal(&fl.fl6_src, &np->saddr) ?
                      &np->saddr :
#endif
                      NULL);

        sk->sk_state = TCP_ESTABLISHED;
out:
        fl6_sock_release(flowlabel);
        return err;
}

void ipv6_icmp_error(struct sock *sk, struct sk_buff *skb, int err,
                     __be16 port, u32 info, u8 *payload)
{
        struct ipv6_pinfo *np  = inet6_sk(sk);
        struct icmp6hdr *icmph = icmp6_hdr(skb);
        struct sock_exterr_skb *serr;

        if (!np->recverr)
                return;

        skb = skb_clone(skb, GFP_ATOMIC);
        if (!skb)
                return;

        serr = SKB_EXT_ERR(skb);
        serr->ee.ee_errno = err;
        serr->ee.ee_origin = SO_EE_ORIGIN_ICMP6;
        serr->ee.ee_type = icmph->icmp6_type;
        serr->ee.ee_code = icmph->icmp6_code;
        serr->ee.ee_pad = 0;
        serr->ee.ee_info = info;
        serr->ee.ee_data = 0;
        serr->addr_offset = (u8 *)&(((struct ipv6hdr *)(icmph + 1))->daddr) -
                                  skb_network_header(skb);
        serr->port = port;

        __skb_pull(skb, payload - skb->data);
        skb_reset_transport_header(skb);

        if (sock_queue_err_skb(sk, skb))
                kfree_skb(skb);
}

void ipv6_local_error(struct sock *sk, int err, struct flowi *fl, u32 info)
{
        struct ipv6_pinfo *np = inet6_sk(sk);
        struct sock_exterr_skb *serr;
        struct ipv6hdr *iph;
        struct sk_buff *skb;

        if (!np->recverr)
                return;

        skb = alloc_skb(sizeof(struct ipv6hdr), GFP_ATOMIC);
        if (!skb)
                return;

        skb_put(skb, sizeof(struct ipv6hdr));
        skb_reset_network_header(skb);
        iph = ipv6_hdr(skb);
        ipv6_addr_copy(&iph->daddr, &fl->fl6_dst);

        serr = SKB_EXT_ERR(skb);
        serr->ee.ee_errno = err;
        serr->ee.ee_origin = SO_EE_ORIGIN_LOCAL;
        serr->ee.ee_type = 0;
        serr->ee.ee_code = 0;
        serr->ee.ee_pad = 0;
        serr->ee.ee_info = info;
        serr->ee.ee_data = 0;
        serr->addr_offset = (u8 *)&iph->daddr - skb_network_header(skb);
        serr->port = fl->fl_ip_dport;

        __skb_pull(skb, skb_tail_pointer(skb) - skb->data);
        skb_reset_transport_header(skb);

        if (sock_queue_err_skb(sk, skb))
                kfree_skb(skb);
}

/*
 *      Handle MSG_ERRQUEUE
 */
int ipv6_recv_error(struct sock *sk, struct msghdr *msg, int len)
{
        struct ipv6_pinfo *np = inet6_sk(sk);
        struct sock_exterr_skb *serr;
        struct sk_buff *skb, *skb2;
        struct sockaddr_in6 *sin;
        struct {
                struct sock_extended_err ee;
                struct sockaddr_in6      offender;
        } errhdr;
        int err;
        int copied;

        err = -EAGAIN;
        skb = skb_dequeue(&sk->sk_error_queue);
        if (skb == NULL)
                goto out;

        copied = skb->len;
        if (copied > len) {
                msg->msg_flags |= MSG_TRUNC;
                copied = len;
        }
        err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
        if (err)
                goto out_free_skb;

        sock_recv_timestamp(msg, sk, skb);

        serr = SKB_EXT_ERR(skb);

        sin = (struct sockaddr_in6 *)msg->msg_name;
        if (sin) {
                const unsigned char *nh = skb_network_header(skb);
                sin->sin6_family = AF_INET6;
                sin->sin6_flowinfo = 0;
                sin->sin6_port = serr->port;
                sin->sin6_scope_id = 0;
                if (serr->ee.ee_origin == SO_EE_ORIGIN_ICMP6) {
                        ipv6_addr_copy(&sin->sin6_addr,
                                  (struct in6_addr *)(nh + serr->addr_offset));
                        if (np->sndflow)
                                sin->sin6_flowinfo =
                                        (*(__be32 *)(nh + serr->addr_offset - 24) &
                                         IPV6_FLOWINFO_MASK);
                        if (ipv6_addr_type(&sin->sin6_addr) & IPV6_ADDR_LINKLOCAL)
                                sin->sin6_scope_id = IP6CB(skb)->iif;
                } else {
                        ipv6_addr_set(&sin->sin6_addr, 0, 0,
                                      htonl(0xffff),
                                      *(__be32 *)(nh + serr->addr_offset));
                }
        }

        memcpy(&errhdr.ee, &serr->ee, sizeof(struct sock_extended_err));
        sin = &errhdr.offender;
        sin->sin6_family = AF_UNSPEC;
        if (serr->ee.ee_origin != SO_EE_ORIGIN_LOCAL) {
                sin->sin6_family = AF_INET6;
                sin->sin6_flowinfo = 0;
                sin->sin6_scope_id = 0;
                if (serr->ee.ee_origin == SO_EE_ORIGIN_ICMP6) {
                        ipv6_addr_copy(&sin->sin6_addr, &ipv6_hdr(skb)->saddr);
                        if (np->rxopt.all)
                                datagram_recv_ctl(sk, msg, skb);
                        if (ipv6_addr_type(&sin->sin6_addr) & IPV6_ADDR_LINKLOCAL)
                                sin->sin6_scope_id = IP6CB(skb)->iif;
                } else {
                        struct inet_sock *inet = inet_sk(sk);

                        ipv6_addr_set(&sin->sin6_addr, 0, 0,
                                      htonl(0xffff), ip_hdr(skb)->saddr);
                        if (inet->cmsg_flags)
                                ip_cmsg_recv(msg, skb);
                }
        }

        put_cmsg(msg, SOL_IPV6, IPV6_RECVERR, sizeof(errhdr), &errhdr);

        /* Now we could try to dump offended packet options */

        msg->msg_flags |= MSG_ERRQUEUE;
        err = copied;

        /* Reset and regenerate socket error */
        spin_lock_bh(&sk->sk_error_queue.lock);
        sk->sk_err = 0;
        if ((skb2 = skb_peek(&sk->sk_error_queue)) != NULL) {
                sk->sk_err = SKB_EXT_ERR(skb2)->ee.ee_errno;
                spin_unlock_bh(&sk->sk_error_queue.lock);
                sk->sk_error_report(sk);
        } else {
                spin_unlock_bh(&sk->sk_error_queue.lock);
        }

out_free_skb:
        kfree_skb(skb);
out:
        return err;
}



int datagram_recv_ctl(struct sock *sk, struct msghdr *msg, struct sk_buff *skb)
{
        struct ipv6_pinfo *np = inet6_sk(sk);
        struct inet6_skb_parm *opt = IP6CB(skb);
        unsigned char *nh = skb_network_header(skb);

        if (np->rxopt.bits.rxinfo) {
                struct in6_pktinfo src_info;

                src_info.ipi6_ifindex = opt->iif;
                ipv6_addr_copy(&src_info.ipi6_addr, &ipv6_hdr(skb)->daddr);
                put_cmsg(msg, SOL_IPV6, IPV6_PKTINFO, sizeof(src_info), &src_info);
        }

        if (np->rxopt.bits.rxhlim) {
                int hlim = ipv6_hdr(skb)->hop_limit;
                put_cmsg(msg, SOL_IPV6, IPV6_HOPLIMIT, sizeof(hlim), &hlim);
        }

        if (np->rxopt.bits.rxtclass) {
                int tclass = (ntohl(*(__be32 *)ipv6_hdr(skb)) >> 20) & 0xff;
                put_cmsg(msg, SOL_IPV6, IPV6_TCLASS, sizeof(tclass), &tclass);
        }

        if (np->rxopt.bits.rxflow && (*(__be32 *)nh & IPV6_FLOWINFO_MASK)) {
                __be32 flowinfo = *(__be32 *)nh & IPV6_FLOWINFO_MASK;
                put_cmsg(msg, SOL_IPV6, IPV6_FLOWINFO, sizeof(flowinfo), &flowinfo);
        }

        /* HbH is allowed only once */
        if (np->rxopt.bits.hopopts && opt->hop) {
                u8 *ptr = nh + opt->hop;
                put_cmsg(msg, SOL_IPV6, IPV6_HOPOPTS, (ptr[1]+1)<<3, ptr);
        }

        if (opt->lastopt &&
            (np->rxopt.bits.dstopts || np->rxopt.bits.srcrt)) {
                /*
                 * Silly enough, but we need to reparse in order to
                 * report extension headers (except for HbH)
                 * in order.
                 *
                 * Also note that IPV6_RECVRTHDRDSTOPTS is NOT
                 * (and WILL NOT be) defined because
                 * IPV6_RECVDSTOPTS is more generic. --yoshfuji
                 */
                unsigned int off = sizeof(struct ipv6hdr);
                u8 nexthdr = ipv6_hdr(skb)->nexthdr;

                while (off <= opt->lastopt) {
                        unsigned len;
                        u8 *ptr = nh + off;

                        switch(nexthdr) {
                        case IPPROTO_DSTOPTS:
                                nexthdr = ptr[0];
                                len = (ptr[1] + 1) << 3;
                                if (np->rxopt.bits.dstopts)
                                        put_cmsg(msg, SOL_IPV6, IPV6_DSTOPTS, len, ptr);
                                break;
                        case IPPROTO_ROUTING:
                                nexthdr = ptr[0];
                                len = (ptr[1] + 1) << 3;
                                if (np->rxopt.bits.srcrt)
                                        put_cmsg(msg, SOL_IPV6, IPV6_RTHDR, len, ptr);
                                break;
                        case IPPROTO_AH:
                                nexthdr = ptr[0];
                                len = (ptr[1] + 2) << 2;
                                break;
                        default:
                                nexthdr = ptr[0];
                                len = (ptr[1] + 1) << 3;
                                break;
                        }

                        off += len;
                }
        }

        /* socket options in old style */
        if (np->rxopt.bits.rxoinfo) {
                struct in6_pktinfo src_info;

                src_info.ipi6_ifindex = opt->iif;
                ipv6_addr_copy(&src_info.ipi6_addr, &ipv6_hdr(skb)->daddr);
                put_cmsg(msg, SOL_IPV6, IPV6_2292PKTINFO, sizeof(src_info), &src_info);
        }
        if (np->rxopt.bits.rxohlim) {
                int hlim = ipv6_hdr(skb)->hop_limit;
                put_cmsg(msg, SOL_IPV6, IPV6_2292HOPLIMIT, sizeof(hlim), &hlim);
        }
        if (np->rxopt.bits.ohopopts && opt->hop) {
                u8 *ptr = nh + opt->hop;
                put_cmsg(msg, SOL_IPV6, IPV6_2292HOPOPTS, (ptr[1]+1)<<3, ptr);
        }
        if (np->rxopt.bits.odstopts && opt->dst0) {
                u8 *ptr = nh + opt->dst0;
                put_cmsg(msg, SOL_IPV6, IPV6_2292DSTOPTS, (ptr[1]+1)<<3, ptr);
        }
        if (np->rxopt.bits.osrcrt && opt->srcrt) {
                struct ipv6_rt_hdr *rthdr = (struct ipv6_rt_hdr *)(nh + opt->srcrt);
                put_cmsg(msg, SOL_IPV6, IPV6_2292RTHDR, (rthdr->hdrlen+1) << 3, rthdr);
        }
        if (np->rxopt.bits.odstopts && opt->dst1) {
                u8 *ptr = nh + opt->dst1;
                put_cmsg(msg, SOL_IPV6, IPV6_2292DSTOPTS, (ptr[1]+1)<<3, ptr);
        }
        return 0;
}

int datagram_send_ctl(struct net *net,
                      struct msghdr *msg, struct flowi *fl,
                      struct ipv6_txoptions *opt,
                      int *hlimit, int *tclass)
{
        struct in6_pktinfo *src_info;
        struct cmsghdr *cmsg;
        struct ipv6_rt_hdr *rthdr;
        struct ipv6_opt_hdr *hdr;
        int len;
        int err = 0;

        for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
                int addr_type;

                if (!CMSG_OK(msg, cmsg)) {
                        err = -EINVAL;
                        goto exit_f;
                }

                if (cmsg->cmsg_level != SOL_IPV6)
                        continue;

                switch (cmsg->cmsg_type) {
                case IPV6_PKTINFO:
                case IPV6_2292PKTINFO:
                    {
                        struct net_device *dev = NULL;

                        if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct in6_pktinfo))) {
                                err = -EINVAL;
                                goto exit_f;
                        }

                        src_info = (struct in6_pktinfo *)CMSG_DATA(cmsg);

                        if (src_info->ipi6_ifindex) {
                                if (fl->oif && src_info->ipi6_ifindex != fl->oif)
                                        return -EINVAL;
                                fl->oif = src_info->ipi6_ifindex;
                        }

                        addr_type = __ipv6_addr_type(&src_info->ipi6_addr);

                        if (fl->oif) {
                                dev = dev_get_by_index(net, fl->oif);
                                if (!dev)
                                        return -ENODEV;
                        } else if (addr_type & IPV6_ADDR_LINKLOCAL)
                                return -EINVAL;

                        if (addr_type != IPV6_ADDR_ANY) {
                                int strict = __ipv6_addr_src_scope(addr_type) <= IPV6_ADDR_SCOPE_LINKLOCAL;
                                if (!ipv6_chk_addr(net, &src_info->ipi6_addr,
                                                   strict ? dev : NULL, 0))
                                        err = -EINVAL;
                                else
                                        ipv6_addr_copy(&fl->fl6_src, &src_info->ipi6_addr);
                        }

                        if (dev)
                                dev_put(dev);

                        if (err)
                                goto exit_f;

                        break;
                    }

                case IPV6_FLOWINFO:
                        if (cmsg->cmsg_len < CMSG_LEN(4)) {
                                err = -EINVAL;
                                goto exit_f;
                        }

                        if (fl->fl6_flowlabel&IPV6_FLOWINFO_MASK) {
                                if ((fl->fl6_flowlabel^*(__be32 *)CMSG_DATA(cmsg))&~IPV6_FLOWINFO_MASK) {
                                        err = -EINVAL;
                                        goto exit_f;
                                }
                        }
                        fl->fl6_flowlabel = IPV6_FLOWINFO_MASK & *(__be32 *)CMSG_DATA(cmsg);
                        break;

                case IPV6_2292HOPOPTS:
                case IPV6_HOPOPTS:
                        if (opt->hopopt || cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
                                err = -EINVAL;
                                goto exit_f;
                        }

                        hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
                        len = ((hdr->hdrlen + 1) << 3);
                        if (cmsg->cmsg_len < CMSG_LEN(len)) {
                                err = -EINVAL;
                                goto exit_f;
                        }
                        if (!capable(CAP_NET_RAW)) {
                                err = -EPERM;
                                goto exit_f;
                        }
                        opt->opt_nflen += len;
                        opt->hopopt = hdr;
                        break;

                case IPV6_2292DSTOPTS:
                        if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
                                err = -EINVAL;
                                goto exit_f;
                        }

                        hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
                        len = ((hdr->hdrlen + 1) << 3);
                        if (cmsg->cmsg_len < CMSG_LEN(len)) {
                                err = -EINVAL;
                                goto exit_f;
                        }
                        if (!capable(CAP_NET_RAW)) {
                                err = -EPERM;
                                goto exit_f;
                        }
                        if (opt->dst1opt) {
                                err = -EINVAL;
                                goto exit_f;
                        }
                        opt->opt_flen += len;
                        opt->dst1opt = hdr;
                        break;

                case IPV6_DSTOPTS:
                case IPV6_RTHDRDSTOPTS:
                        if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_opt_hdr))) {
                                err = -EINVAL;
                                goto exit_f;
                        }

                        hdr = (struct ipv6_opt_hdr *)CMSG_DATA(cmsg);
                        len = ((hdr->hdrlen + 1) << 3);
                        if (cmsg->cmsg_len < CMSG_LEN(len)) {
                                err = -EINVAL;
                                goto exit_f;
                        }
                        if (!capable(CAP_NET_RAW)) {
                                err = -EPERM;
                                goto exit_f;
                        }
                        if (cmsg->cmsg_type == IPV6_DSTOPTS) {
                                opt->opt_flen += len;
                                opt->dst1opt = hdr;
                        } else {
                                opt->opt_nflen += len;
                                opt->dst0opt = hdr;
                        }
                        break;

                case IPV6_2292RTHDR:
                case IPV6_RTHDR:
                        if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct ipv6_rt_hdr))) {
                                err = -EINVAL;
                                goto exit_f;
                        }

                        rthdr = (struct ipv6_rt_hdr *)CMSG_DATA(cmsg);

                        switch (rthdr->type) {
#if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
                        case IPV6_SRCRT_TYPE_2:
                                break;
#endif
                        default:
                                err = -EINVAL;
                                goto exit_f;
                        }

                        len = ((rthdr->hdrlen + 1) << 3);

                        if (cmsg->cmsg_len < CMSG_LEN(len)) {
                                err = -EINVAL;
                                goto exit_f;
                        }

                        /* segments left must also match */
                        if ((rthdr->hdrlen >> 1) != rthdr->segments_left) {
                                err = -EINVAL;
                                goto exit_f;
                        }

                        opt->opt_nflen += len;
                        opt->srcrt = rthdr;

                        if (cmsg->cmsg_type == IPV6_2292RTHDR && opt->dst1opt) {
                                int dsthdrlen = ((opt->dst1opt->hdrlen+1)<<3);

                                opt->opt_nflen += dsthdrlen;
                                opt->dst0opt = opt->dst1opt;
                                opt->dst1opt = NULL;
                                opt->opt_flen -= dsthdrlen;
                        }

                        break;

                case IPV6_2292HOPLIMIT:
                case IPV6_HOPLIMIT:
                        if (cmsg->cmsg_len != CMSG_LEN(sizeof(int))) {
                                err = -EINVAL;
                                goto exit_f;
                        }

                        *hlimit = *(int *)CMSG_DATA(cmsg);
                        if (*hlimit < -1 || *hlimit > 0xff) {
                                err = -EINVAL;
                                goto exit_f;
                        }

                        break;

                case IPV6_TCLASS:
                    {
                        int tc;

                        err = -EINVAL;
                        if (cmsg->cmsg_len != CMSG_LEN(sizeof(int))) {
                                goto exit_f;
                        }

                        tc = *(int *)CMSG_DATA(cmsg);
                        if (tc < -1 || tc > 0xff)
                                goto exit_f;

                        err = 0;
                        *tclass = tc;

                        break;
                    }
                default:
                        LIMIT_NETDEBUG(KERN_DEBUG "invalid cmsg type: %d\n",
                                       cmsg->cmsg_type);
                        err = -EINVAL;
                        goto exit_f;
                }
        }

exit_f:
        return err;
}

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