root/net/ipv4/ip_sockglue.c
// SPDX-License-Identifier: GPL-2.0
/*
 * INET         An implementation of the TCP/IP protocol suite for the LINUX
 *              operating system.  INET is implemented using the  BSD Socket
 *              interface as the means of communication with the user level.
 *
 *              The IP to API glue.
 *
 * Authors:     see ip.c
 *
 * Fixes:
 *              Many            :       Split from ip.c , see ip.c for history.
 *              Martin Mares    :       TOS setting fixed.
 *              Alan Cox        :       Fixed a couple of oopses in Martin's
 *                                      TOS tweaks.
 *              Mike McLagan    :       Routing by source
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/mm.h>
#include <linux/skbuff.h>
#include <linux/ip.h>
#include <linux/icmp.h>
#include <linux/inetdevice.h>
#include <linux/netdevice.h>
#include <linux/slab.h>
#include <net/sock.h>
#include <net/ip.h>
#include <net/icmp.h>
#include <net/tcp_states.h>
#include <linux/udp.h>
#include <linux/igmp.h>
#include <linux/netfilter.h>
#include <linux/route.h>
#include <linux/mroute.h>
#include <net/inet_ecn.h>
#include <net/route.h>
#include <net/xfrm.h>
#include <net/compat.h>
#include <net/checksum.h>
#if IS_ENABLED(CONFIG_IPV6)
#include <net/transp_v6.h>
#endif
#include <net/ip_fib.h>

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

/*
 *      SOL_IP control messages.
 */

static void ip_cmsg_recv_pktinfo(struct msghdr *msg, struct sk_buff *skb)
{
        struct in_pktinfo info = *PKTINFO_SKB_CB(skb);

        info.ipi_addr.s_addr = ip_hdr(skb)->daddr;

        put_cmsg(msg, SOL_IP, IP_PKTINFO, sizeof(info), &info);
}

static void ip_cmsg_recv_ttl(struct msghdr *msg, struct sk_buff *skb)
{
        int ttl = ip_hdr(skb)->ttl;
        put_cmsg(msg, SOL_IP, IP_TTL, sizeof(int), &ttl);
}

static void ip_cmsg_recv_tos(struct msghdr *msg, struct sk_buff *skb)
{
        put_cmsg(msg, SOL_IP, IP_TOS, 1, &ip_hdr(skb)->tos);
}

static void ip_cmsg_recv_opts(struct msghdr *msg, struct sk_buff *skb)
{
        if (IPCB(skb)->opt.optlen == 0)
                return;

        put_cmsg(msg, SOL_IP, IP_RECVOPTS, IPCB(skb)->opt.optlen,
                 ip_hdr(skb) + 1);
}


static void ip_cmsg_recv_retopts(struct net *net, struct msghdr *msg,
                                 struct sk_buff *skb)
{
        unsigned char optbuf[sizeof(struct ip_options) + 40];
        struct ip_options *opt = (struct ip_options *)optbuf;

        if (IPCB(skb)->opt.optlen == 0)
                return;

        if (ip_options_echo(net, opt, skb)) {
                msg->msg_flags |= MSG_CTRUNC;
                return;
        }
        ip_options_undo(opt);

        put_cmsg(msg, SOL_IP, IP_RETOPTS, opt->optlen, opt->__data);
}

static void ip_cmsg_recv_fragsize(struct msghdr *msg, struct sk_buff *skb)
{
        int val;

        if (IPCB(skb)->frag_max_size == 0)
                return;

        val = IPCB(skb)->frag_max_size;
        put_cmsg(msg, SOL_IP, IP_RECVFRAGSIZE, sizeof(val), &val);
}

static void ip_cmsg_recv_checksum(struct msghdr *msg, struct sk_buff *skb,
                                  int tlen, int offset)
{
        __wsum csum = skb->csum;

        if (skb->ip_summed != CHECKSUM_COMPLETE)
                return;

        if (offset != 0) {
                int tend_off = skb_transport_offset(skb) + tlen;
                csum = csum_sub(csum, skb_checksum(skb, tend_off, offset, 0));
        }

        put_cmsg(msg, SOL_IP, IP_CHECKSUM, sizeof(__wsum), &csum);
}

static void ip_cmsg_recv_security(struct msghdr *msg, struct sk_buff *skb)
{
        struct lsm_context ctx;
        u32 secid;
        int err;

        err = security_socket_getpeersec_dgram(NULL, skb, &secid);
        if (err)
                return;

        err = security_secid_to_secctx(secid, &ctx);
        if (err < 0)
                return;

        put_cmsg(msg, SOL_IP, SCM_SECURITY, ctx.len, ctx.context);
        security_release_secctx(&ctx);
}

static void ip_cmsg_recv_dstaddr(struct msghdr *msg, struct sk_buff *skb)
{
        __be16 _ports[2], *ports;
        struct sockaddr_in sin;

        /* All current transport protocols have the port numbers in the
         * first four bytes of the transport header and this function is
         * written with this assumption in mind.
         */
        ports = skb_header_pointer(skb, skb_transport_offset(skb),
                                   sizeof(_ports), &_ports);
        if (!ports)
                return;

        sin.sin_family = AF_INET;
        sin.sin_addr.s_addr = ip_hdr(skb)->daddr;
        sin.sin_port = ports[1];
        memset(sin.sin_zero, 0, sizeof(sin.sin_zero));

        put_cmsg(msg, SOL_IP, IP_ORIGDSTADDR, sizeof(sin), &sin);
}

void ip_cmsg_recv_offset(struct msghdr *msg, struct sock *sk,
                         struct sk_buff *skb, int tlen, int offset)
{
        unsigned long flags = inet_cmsg_flags(inet_sk(sk));

        if (!flags)
                return;

        /* Ordered by supposed usage frequency */
        if (flags & IP_CMSG_PKTINFO) {
                ip_cmsg_recv_pktinfo(msg, skb);

                flags &= ~IP_CMSG_PKTINFO;
                if (!flags)
                        return;
        }

        if (flags & IP_CMSG_TTL) {
                ip_cmsg_recv_ttl(msg, skb);

                flags &= ~IP_CMSG_TTL;
                if (!flags)
                        return;
        }

        if (flags & IP_CMSG_TOS) {
                ip_cmsg_recv_tos(msg, skb);

                flags &= ~IP_CMSG_TOS;
                if (!flags)
                        return;
        }

        if (flags & IP_CMSG_RECVOPTS) {
                ip_cmsg_recv_opts(msg, skb);

                flags &= ~IP_CMSG_RECVOPTS;
                if (!flags)
                        return;
        }

        if (flags & IP_CMSG_RETOPTS) {
                ip_cmsg_recv_retopts(sock_net(sk), msg, skb);

                flags &= ~IP_CMSG_RETOPTS;
                if (!flags)
                        return;
        }

        if (flags & IP_CMSG_PASSSEC) {
                ip_cmsg_recv_security(msg, skb);

                flags &= ~IP_CMSG_PASSSEC;
                if (!flags)
                        return;
        }

        if (flags & IP_CMSG_ORIGDSTADDR) {
                ip_cmsg_recv_dstaddr(msg, skb);

                flags &= ~IP_CMSG_ORIGDSTADDR;
                if (!flags)
                        return;
        }

        if (flags & IP_CMSG_CHECKSUM)
                ip_cmsg_recv_checksum(msg, skb, tlen, offset);

        if (flags & IP_CMSG_RECVFRAGSIZE)
                ip_cmsg_recv_fragsize(msg, skb);
}
EXPORT_SYMBOL(ip_cmsg_recv_offset);

int ip_cmsg_send(struct sock *sk, struct msghdr *msg, struct ipcm_cookie *ipc,
                 bool allow_ipv6)
{
        int err, val;
        struct cmsghdr *cmsg;
        struct net *net = sock_net(sk);

        for_each_cmsghdr(cmsg, msg) {
                if (!CMSG_OK(msg, cmsg))
                        return -EINVAL;
#if IS_ENABLED(CONFIG_IPV6)
                if (allow_ipv6 &&
                    cmsg->cmsg_level == SOL_IPV6 &&
                    cmsg->cmsg_type == IPV6_PKTINFO) {
                        struct in6_pktinfo *src_info;

                        if (cmsg->cmsg_len < CMSG_LEN(sizeof(*src_info)))
                                return -EINVAL;
                        src_info = (struct in6_pktinfo *)CMSG_DATA(cmsg);
                        if (!ipv6_addr_v4mapped(&src_info->ipi6_addr))
                                return -EINVAL;
                        if (src_info->ipi6_ifindex)
                                ipc->oif = src_info->ipi6_ifindex;
                        ipc->addr = src_info->ipi6_addr.s6_addr32[3];
                        continue;
                }
#endif
                if (cmsg->cmsg_level == SOL_SOCKET) {
                        err = __sock_cmsg_send(sk, cmsg, &ipc->sockc);
                        if (err)
                                return err;
                        continue;
                }

                if (cmsg->cmsg_level != SOL_IP)
                        continue;
                switch (cmsg->cmsg_type) {
                case IP_RETOPTS:
                        err = cmsg->cmsg_len - sizeof(struct cmsghdr);

                        /* Our caller is responsible for freeing ipc->opt */
                        err = ip_options_get(net, &ipc->opt,
                                             KERNEL_SOCKPTR(CMSG_DATA(cmsg)),
                                             err < 40 ? err : 40);
                        if (err)
                                return err;
                        break;
                case IP_PKTINFO:
                {
                        struct in_pktinfo *info;
                        if (cmsg->cmsg_len != CMSG_LEN(sizeof(struct in_pktinfo)))
                                return -EINVAL;
                        info = (struct in_pktinfo *)CMSG_DATA(cmsg);
                        if (info->ipi_ifindex)
                                ipc->oif = info->ipi_ifindex;
                        ipc->addr = info->ipi_spec_dst.s_addr;
                        break;
                }
                case IP_TTL:
                        if (cmsg->cmsg_len != CMSG_LEN(sizeof(int)))
                                return -EINVAL;
                        val = *(int *)CMSG_DATA(cmsg);
                        if (val < 1 || val > 255)
                                return -EINVAL;
                        ipc->ttl = val;
                        break;
                case IP_TOS:
                        if (cmsg->cmsg_len == CMSG_LEN(sizeof(int)))
                                val = *(int *)CMSG_DATA(cmsg);
                        else if (cmsg->cmsg_len == CMSG_LEN(sizeof(u8)))
                                val = *(u8 *)CMSG_DATA(cmsg);
                        else
                                return -EINVAL;
                        if (val < 0 || val > 255)
                                return -EINVAL;
                        ipc->tos = val;
                        ipc->sockc.priority = rt_tos2priority(ipc->tos);
                        break;
                case IP_PROTOCOL:
                        if (cmsg->cmsg_len != CMSG_LEN(sizeof(int)))
                                return -EINVAL;
                        val = *(int *)CMSG_DATA(cmsg);
                        if (val < 1 || val > 255)
                                return -EINVAL;
                        ipc->protocol = val;
                        break;
                default:
                        return -EINVAL;
                }
        }
        return 0;
}

static void ip_ra_destroy_rcu(struct rcu_head *head)
{
        struct ip_ra_chain *ra = container_of(head, struct ip_ra_chain, rcu);

        sock_put(ra->saved_sk);
        kfree(ra);
}

int ip_ra_control(struct sock *sk, unsigned char on,
                  void (*destructor)(struct sock *))
{
        struct ip_ra_chain *ra, *new_ra;
        struct ip_ra_chain __rcu **rap;
        struct net *net = sock_net(sk);

        if (sk->sk_type != SOCK_RAW || inet_sk(sk)->inet_num == IPPROTO_RAW)
                return -EINVAL;

        new_ra = on ? kmalloc_obj(*new_ra) : NULL;
        if (on && !new_ra)
                return -ENOMEM;

        mutex_lock(&net->ipv4.ra_mutex);
        for (rap = &net->ipv4.ra_chain;
             (ra = rcu_dereference_protected(*rap,
                        lockdep_is_held(&net->ipv4.ra_mutex))) != NULL;
             rap = &ra->next) {
                if (ra->sk == sk) {
                        if (on) {
                                mutex_unlock(&net->ipv4.ra_mutex);
                                kfree(new_ra);
                                return -EADDRINUSE;
                        }
                        /* dont let ip_call_ra_chain() use sk again */
                        ra->sk = NULL;
                        RCU_INIT_POINTER(*rap, ra->next);
                        mutex_unlock(&net->ipv4.ra_mutex);

                        if (ra->destructor)
                                ra->destructor(sk);
                        /*
                         * Delay sock_put(sk) and kfree(ra) after one rcu grace
                         * period. This guarantee ip_call_ra_chain() dont need
                         * to mess with socket refcounts.
                         */
                        ra->saved_sk = sk;
                        call_rcu(&ra->rcu, ip_ra_destroy_rcu);
                        return 0;
                }
        }
        if (!new_ra) {
                mutex_unlock(&net->ipv4.ra_mutex);
                return -ENOBUFS;
        }
        new_ra->sk = sk;
        new_ra->destructor = destructor;

        RCU_INIT_POINTER(new_ra->next, ra);
        rcu_assign_pointer(*rap, new_ra);
        sock_hold(sk);
        mutex_unlock(&net->ipv4.ra_mutex);

        return 0;
}

static void ipv4_icmp_error_rfc4884(const struct sk_buff *skb,
                                    struct sock_ee_data_rfc4884 *out)
{
        switch (icmp_hdr(skb)->type) {
        case ICMP_DEST_UNREACH:
        case ICMP_TIME_EXCEEDED:
        case ICMP_PARAMETERPROB:
                ip_icmp_error_rfc4884(skb, out, sizeof(struct icmphdr),
                                      icmp_hdr(skb)->un.reserved[1] * 4);
        }
}

void ip_icmp_error(struct sock *sk, struct sk_buff *skb, int err,
                   __be16 port, u32 info, u8 *payload)
{
        struct sock_exterr_skb *serr;

        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_ICMP;
        serr->ee.ee_type = icmp_hdr(skb)->type;
        serr->ee.ee_code = icmp_hdr(skb)->code;
        serr->ee.ee_pad = 0;
        serr->ee.ee_info = info;
        serr->ee.ee_data = 0;
        serr->addr_offset = (u8 *)&(((struct iphdr *)(icmp_hdr(skb) + 1))->daddr) -
                                   skb_network_header(skb);
        serr->port = port;

        if (skb_pull(skb, payload - skb->data)) {
                if (inet_test_bit(RECVERR_RFC4884, sk))
                        ipv4_icmp_error_rfc4884(skb, &serr->ee.ee_rfc4884);

                skb_reset_transport_header(skb);
                if (sock_queue_err_skb(sk, skb) == 0)
                        return;
        }
        kfree_skb(skb);
}
EXPORT_SYMBOL_GPL(ip_icmp_error);

void ip_local_error(struct sock *sk, int err, __be32 daddr, __be16 port, u32 info)
{
        struct sock_exterr_skb *serr;
        struct iphdr *iph;
        struct sk_buff *skb;

        if (!inet_test_bit(RECVERR, sk))
                return;

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

        skb_put(skb, sizeof(struct iphdr));
        skb_reset_network_header(skb);
        iph = ip_hdr(skb);
        iph->daddr = daddr;

        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 = port;

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

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

/* For some errors we have valid addr_offset even with zero payload and
 * zero port. Also, addr_offset should be supported if port is set.
 */
static inline bool ipv4_datagram_support_addr(struct sock_exterr_skb *serr)
{
        return serr->ee.ee_origin == SO_EE_ORIGIN_ICMP ||
               serr->ee.ee_origin == SO_EE_ORIGIN_LOCAL || serr->port;
}

/* IPv4 supports cmsg on all imcp errors and some timestamps
 *
 * Timestamp code paths do not initialize the fields expected by cmsg:
 * the PKTINFO fields in skb->cb[]. Fill those in here.
 */
static bool ipv4_datagram_support_cmsg(const struct sock *sk,
                                       struct sk_buff *skb,
                                       int ee_origin)
{
        struct in_pktinfo *info;

        if (ee_origin == SO_EE_ORIGIN_ICMP)
                return true;

        if (ee_origin == SO_EE_ORIGIN_LOCAL)
                return false;

        /* Support IP_PKTINFO on tstamp packets if requested, to correlate
         * timestamp with egress dev. Not possible for packets without iif
         * or without payload (SOF_TIMESTAMPING_OPT_TSONLY).
         */
        info = PKTINFO_SKB_CB(skb);
        if (!(READ_ONCE(sk->sk_tsflags) & SOF_TIMESTAMPING_OPT_CMSG) ||
            !info->ipi_ifindex)
                return false;

        info->ipi_spec_dst.s_addr = ip_hdr(skb)->saddr;
        return true;
}

/*
 *      Handle MSG_ERRQUEUE
 */
int ip_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len)
{
        struct sock_exterr_skb *serr;
        struct sk_buff *skb;
        DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
        struct {
                struct sock_extended_err ee;
                struct sockaddr_in       offender;
        } errhdr;
        int err;
        int copied;

        err = -EAGAIN;
        skb = sock_dequeue_err_skb(sk);
        if (!skb)
                goto out;

        copied = skb->len;
        if (copied > len) {
                msg->msg_flags |= MSG_TRUNC;
                copied = len;
        }
        err = skb_copy_datagram_msg(skb, 0, msg, copied);
        if (unlikely(err)) {
                kfree_skb(skb);
                return err;
        }
        sock_recv_timestamp(msg, sk, skb);

        serr = SKB_EXT_ERR(skb);

        if (sin && ipv4_datagram_support_addr(serr)) {
                sin->sin_family = AF_INET;
                sin->sin_addr.s_addr = *(__be32 *)(skb_network_header(skb) +
                                                   serr->addr_offset);
                sin->sin_port = serr->port;
                memset(&sin->sin_zero, 0, sizeof(sin->sin_zero));
                *addr_len = sizeof(*sin);
        }

        memcpy(&errhdr.ee, &serr->ee, sizeof(struct sock_extended_err));
        sin = &errhdr.offender;
        memset(sin, 0, sizeof(*sin));

        if (ipv4_datagram_support_cmsg(sk, skb, serr->ee.ee_origin)) {
                sin->sin_family = AF_INET;
                sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
                if (inet_cmsg_flags(inet_sk(sk)))
                        ip_cmsg_recv(msg, skb);
        }

        put_cmsg(msg, SOL_IP, IP_RECVERR, sizeof(errhdr), &errhdr);

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

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

        consume_skb(skb);
out:
        return err;
}

void __ip_sock_set_tos(struct sock *sk, int val)
{
        u8 old_tos = inet_sk(sk)->tos;

        if (sk->sk_type == SOCK_STREAM) {
                val &= ~INET_ECN_MASK;
                val |= old_tos & INET_ECN_MASK;
        }
        if (old_tos != val) {
                WRITE_ONCE(inet_sk(sk)->tos, val);
                WRITE_ONCE(sk->sk_priority, rt_tos2priority(val));
                sk_dst_reset(sk);
        }
}

void ip_sock_set_tos(struct sock *sk, int val)
{
        sockopt_lock_sock(sk);
        __ip_sock_set_tos(sk, val);
        sockopt_release_sock(sk);
}
EXPORT_SYMBOL(ip_sock_set_tos);

void ip_sock_set_freebind(struct sock *sk)
{
        inet_set_bit(FREEBIND, sk);
}
EXPORT_SYMBOL(ip_sock_set_freebind);

void ip_sock_set_recverr(struct sock *sk)
{
        inet_set_bit(RECVERR, sk);
}
EXPORT_SYMBOL(ip_sock_set_recverr);

int ip_sock_set_mtu_discover(struct sock *sk, int val)
{
        if (val < IP_PMTUDISC_DONT || val > IP_PMTUDISC_OMIT)
                return -EINVAL;
        WRITE_ONCE(inet_sk(sk)->pmtudisc, val);
        return 0;
}
EXPORT_SYMBOL(ip_sock_set_mtu_discover);

void ip_sock_set_pktinfo(struct sock *sk)
{
        inet_set_bit(PKTINFO, sk);
}
EXPORT_SYMBOL(ip_sock_set_pktinfo);

/*
 *      Socket option code for IP. This is the end of the line after any
 *      TCP,UDP etc options on an IP socket.
 */
static bool setsockopt_needs_rtnl(int optname)
{
        switch (optname) {
        case IP_ADD_MEMBERSHIP:
        case IP_ADD_SOURCE_MEMBERSHIP:
        case IP_BLOCK_SOURCE:
        case IP_DROP_MEMBERSHIP:
        case IP_DROP_SOURCE_MEMBERSHIP:
        case IP_MSFILTER:
        case IP_UNBLOCK_SOURCE:
        case MCAST_BLOCK_SOURCE:
        case MCAST_MSFILTER:
        case MCAST_JOIN_GROUP:
        case MCAST_JOIN_SOURCE_GROUP:
        case MCAST_LEAVE_GROUP:
        case MCAST_LEAVE_SOURCE_GROUP:
        case MCAST_UNBLOCK_SOURCE:
                return true;
        }
        return false;
}

static int set_mcast_msfilter(struct sock *sk, int ifindex,
                              int numsrc, int fmode,
                              struct sockaddr_storage *group,
                              struct sockaddr_storage *list)
{
        struct ip_msfilter *msf;
        struct sockaddr_in *psin;
        int err, i;

        msf = kmalloc(IP_MSFILTER_SIZE(numsrc), GFP_KERNEL);
        if (!msf)
                return -ENOBUFS;

        psin = (struct sockaddr_in *)group;
        if (psin->sin_family != AF_INET)
                goto Eaddrnotavail;
        msf->imsf_multiaddr = psin->sin_addr.s_addr;
        msf->imsf_interface = 0;
        msf->imsf_fmode = fmode;
        msf->imsf_numsrc = numsrc;
        for (i = 0; i < numsrc; ++i) {
                psin = (struct sockaddr_in *)&list[i];

                if (psin->sin_family != AF_INET)
                        goto Eaddrnotavail;
                msf->imsf_slist_flex[i] = psin->sin_addr.s_addr;
        }
        err = ip_mc_msfilter(sk, msf, ifindex);
        kfree(msf);
        return err;

Eaddrnotavail:
        kfree(msf);
        return -EADDRNOTAVAIL;
}

static int copy_group_source_from_sockptr(struct group_source_req *greqs,
                sockptr_t optval, int optlen)
{
        if (in_compat_syscall()) {
                struct compat_group_source_req gr32;

                if (optlen != sizeof(gr32))
                        return -EINVAL;
                if (copy_from_sockptr(&gr32, optval, sizeof(gr32)))
                        return -EFAULT;
                greqs->gsr_interface = gr32.gsr_interface;
                greqs->gsr_group = gr32.gsr_group;
                greqs->gsr_source = gr32.gsr_source;
        } else {
                if (optlen != sizeof(*greqs))
                        return -EINVAL;
                if (copy_from_sockptr(greqs, optval, sizeof(*greqs)))
                        return -EFAULT;
        }

        return 0;
}

static int do_mcast_group_source(struct sock *sk, int optname,
                sockptr_t optval, int optlen)
{
        struct group_source_req greqs;
        struct ip_mreq_source mreqs;
        struct sockaddr_in *psin;
        int omode, add, err;

        err = copy_group_source_from_sockptr(&greqs, optval, optlen);
        if (err)
                return err;

        if (greqs.gsr_group.ss_family != AF_INET ||
            greqs.gsr_source.ss_family != AF_INET)
                return -EADDRNOTAVAIL;

        psin = (struct sockaddr_in *)&greqs.gsr_group;
        mreqs.imr_multiaddr = psin->sin_addr.s_addr;
        psin = (struct sockaddr_in *)&greqs.gsr_source;
        mreqs.imr_sourceaddr = psin->sin_addr.s_addr;
        mreqs.imr_interface = 0; /* use index for mc_source */

        if (optname == MCAST_BLOCK_SOURCE) {
                omode = MCAST_EXCLUDE;
                add = 1;
        } else if (optname == MCAST_UNBLOCK_SOURCE) {
                omode = MCAST_EXCLUDE;
                add = 0;
        } else if (optname == MCAST_JOIN_SOURCE_GROUP) {
                struct ip_mreqn mreq;

                psin = (struct sockaddr_in *)&greqs.gsr_group;
                mreq.imr_multiaddr = psin->sin_addr;
                mreq.imr_address.s_addr = 0;
                mreq.imr_ifindex = greqs.gsr_interface;
                err = ip_mc_join_group_ssm(sk, &mreq, MCAST_INCLUDE);
                if (err && err != -EADDRINUSE)
                        return err;
                greqs.gsr_interface = mreq.imr_ifindex;
                omode = MCAST_INCLUDE;
                add = 1;
        } else /* MCAST_LEAVE_SOURCE_GROUP */ {
                omode = MCAST_INCLUDE;
                add = 0;
        }
        return ip_mc_source(add, omode, sk, &mreqs, greqs.gsr_interface);
}

static int ip_set_mcast_msfilter(struct sock *sk, sockptr_t optval, int optlen)
{
        struct group_filter *gsf = NULL;
        int err;

        if (optlen < GROUP_FILTER_SIZE(0))
                return -EINVAL;
        if (optlen > READ_ONCE(sock_net(sk)->core.sysctl_optmem_max))
                return -ENOBUFS;

        gsf = memdup_sockptr(optval, optlen);
        if (IS_ERR(gsf))
                return PTR_ERR(gsf);

        /* numsrc >= (4G-140)/128 overflow in 32 bits */
        err = -ENOBUFS;
        if (gsf->gf_numsrc >= 0x1ffffff ||
            gsf->gf_numsrc > READ_ONCE(sock_net(sk)->ipv4.sysctl_igmp_max_msf))
                goto out_free_gsf;

        err = -EINVAL;
        if (GROUP_FILTER_SIZE(gsf->gf_numsrc) > optlen)
                goto out_free_gsf;

        err = set_mcast_msfilter(sk, gsf->gf_interface, gsf->gf_numsrc,
                                 gsf->gf_fmode, &gsf->gf_group,
                                 gsf->gf_slist_flex);
out_free_gsf:
        kfree(gsf);
        return err;
}

static int compat_ip_set_mcast_msfilter(struct sock *sk, sockptr_t optval,
                int optlen)
{
        const int size0 = offsetof(struct compat_group_filter, gf_slist_flex);
        struct compat_group_filter *gf32;
        unsigned int n;
        void *p;
        int err;

        if (optlen < size0)
                return -EINVAL;
        if (optlen > READ_ONCE(sock_net(sk)->core.sysctl_optmem_max) - 4)
                return -ENOBUFS;

        p = kmalloc(optlen + 4, GFP_KERNEL);
        if (!p)
                return -ENOMEM;
        gf32 = p + 4; /* we want ->gf_group and ->gf_slist_flex aligned */

        err = -EFAULT;
        if (copy_from_sockptr(gf32, optval, optlen))
                goto out_free_gsf;

        /* numsrc >= (4G-140)/128 overflow in 32 bits */
        n = gf32->gf_numsrc;
        err = -ENOBUFS;
        if (n >= 0x1ffffff)
                goto out_free_gsf;

        err = -EINVAL;
        if (offsetof(struct compat_group_filter, gf_slist_flex[n]) > optlen)
                goto out_free_gsf;

        /* numsrc >= (4G-140)/128 overflow in 32 bits */
        err = -ENOBUFS;
        if (n > READ_ONCE(sock_net(sk)->ipv4.sysctl_igmp_max_msf))
                goto out_free_gsf;
        err = set_mcast_msfilter(sk, gf32->gf_interface, n, gf32->gf_fmode,
                                 &gf32->gf_group, gf32->gf_slist_flex);
out_free_gsf:
        kfree(p);
        return err;
}

static int ip_mcast_join_leave(struct sock *sk, int optname,
                sockptr_t optval, int optlen)
{
        struct ip_mreqn mreq = { };
        struct sockaddr_in *psin;
        struct group_req greq;

        if (optlen < sizeof(struct group_req))
                return -EINVAL;
        if (copy_from_sockptr(&greq, optval, sizeof(greq)))
                return -EFAULT;

        psin = (struct sockaddr_in *)&greq.gr_group;
        if (psin->sin_family != AF_INET)
                return -EINVAL;
        mreq.imr_multiaddr = psin->sin_addr;
        mreq.imr_ifindex = greq.gr_interface;
        if (optname == MCAST_JOIN_GROUP)
                return ip_mc_join_group(sk, &mreq);
        return ip_mc_leave_group(sk, &mreq);
}

static int compat_ip_mcast_join_leave(struct sock *sk, int optname,
                sockptr_t optval, int optlen)
{
        struct compat_group_req greq;
        struct ip_mreqn mreq = { };
        struct sockaddr_in *psin;

        if (optlen < sizeof(struct compat_group_req))
                return -EINVAL;
        if (copy_from_sockptr(&greq, optval, sizeof(greq)))
                return -EFAULT;

        psin = (struct sockaddr_in *)&greq.gr_group;
        if (psin->sin_family != AF_INET)
                return -EINVAL;
        mreq.imr_multiaddr = psin->sin_addr;
        mreq.imr_ifindex = greq.gr_interface;

        if (optname == MCAST_JOIN_GROUP)
                return ip_mc_join_group(sk, &mreq);
        return ip_mc_leave_group(sk, &mreq);
}

DEFINE_STATIC_KEY_FALSE(ip4_min_ttl);

int do_ip_setsockopt(struct sock *sk, int level, int optname,
                     sockptr_t optval, unsigned int optlen)
{
        struct inet_sock *inet = inet_sk(sk);
        struct net *net = sock_net(sk);
        int val = 0, err, retv;
        bool needs_rtnl = setsockopt_needs_rtnl(optname);

        switch (optname) {
        case IP_PKTINFO:
        case IP_RECVTTL:
        case IP_RECVOPTS:
        case IP_RECVTOS:
        case IP_RETOPTS:
        case IP_TOS:
        case IP_TTL:
        case IP_HDRINCL:
        case IP_MTU_DISCOVER:
        case IP_RECVERR:
        case IP_ROUTER_ALERT:
        case IP_FREEBIND:
        case IP_PASSSEC:
        case IP_TRANSPARENT:
        case IP_MINTTL:
        case IP_NODEFRAG:
        case IP_BIND_ADDRESS_NO_PORT:
        case IP_UNICAST_IF:
        case IP_MULTICAST_TTL:
        case IP_MULTICAST_ALL:
        case IP_MULTICAST_LOOP:
        case IP_RECVORIGDSTADDR:
        case IP_CHECKSUM:
        case IP_RECVFRAGSIZE:
        case IP_RECVERR_RFC4884:
        case IP_LOCAL_PORT_RANGE:
                if (optlen >= sizeof(int)) {
                        if (copy_from_sockptr(&val, optval, sizeof(val)))
                                return -EFAULT;
                } else if (optlen >= sizeof(char)) {
                        unsigned char ucval;

                        if (copy_from_sockptr(&ucval, optval, sizeof(ucval)))
                                return -EFAULT;
                        val = (int) ucval;
                }
        }

        /* If optlen==0, it is equivalent to val == 0 */

        if (optname == IP_ROUTER_ALERT) {
                retv = ip_ra_control(sk, val ? 1 : 0, NULL);
                if (retv == 0)
                        inet_assign_bit(RTALERT, sk, val);
                return retv;
        }
        if (ip_mroute_opt(optname))
                return ip_mroute_setsockopt(sk, optname, optval, optlen);

        /* Handle options that can be set without locking the socket. */
        switch (optname) {
        case IP_PKTINFO:
                inet_assign_bit(PKTINFO, sk, val);
                return 0;
        case IP_RECVTTL:
                inet_assign_bit(TTL, sk, val);
                return 0;
        case IP_RECVTOS:
                inet_assign_bit(TOS, sk, val);
                return 0;
        case IP_RECVOPTS:
                inet_assign_bit(RECVOPTS, sk, val);
                return 0;
        case IP_RETOPTS:
                inet_assign_bit(RETOPTS, sk, val);
                return 0;
        case IP_PASSSEC:
                inet_assign_bit(PASSSEC, sk, val);
                return 0;
        case IP_RECVORIGDSTADDR:
                inet_assign_bit(ORIGDSTADDR, sk, val);
                return 0;
        case IP_RECVFRAGSIZE:
                if (sk->sk_type != SOCK_RAW && sk->sk_type != SOCK_DGRAM)
                        return -EINVAL;
                inet_assign_bit(RECVFRAGSIZE, sk, val);
                return 0;
        case IP_RECVERR:
                inet_assign_bit(RECVERR, sk, val);
                if (!val)
                        skb_errqueue_purge(&sk->sk_error_queue);
                return 0;
        case IP_RECVERR_RFC4884:
                if (val < 0 || val > 1)
                        return -EINVAL;
                inet_assign_bit(RECVERR_RFC4884, sk, val);
                return 0;
        case IP_FREEBIND:
                if (optlen < 1)
                        return -EINVAL;
                inet_assign_bit(FREEBIND, sk, val);
                return 0;
        case IP_HDRINCL:
                if (sk->sk_type != SOCK_RAW)
                        return -ENOPROTOOPT;
                inet_assign_bit(HDRINCL, sk, val);
                return 0;
        case IP_MULTICAST_LOOP:
                if (optlen < 1)
                        return -EINVAL;
                inet_assign_bit(MC_LOOP, sk, val);
                return 0;
        case IP_MULTICAST_ALL:
                if (optlen < 1)
                        return -EINVAL;
                if (val != 0 && val != 1)
                        return -EINVAL;
                inet_assign_bit(MC_ALL, sk, val);
                return 0;
        case IP_TRANSPARENT:
                if (!!val && !sockopt_ns_capable(sock_net(sk)->user_ns, CAP_NET_RAW) &&
                    !sockopt_ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
                        return -EPERM;
                if (optlen < 1)
                        return -EINVAL;
                inet_assign_bit(TRANSPARENT, sk, val);
                return 0;
        case IP_NODEFRAG:
                if (sk->sk_type != SOCK_RAW)
                        return -ENOPROTOOPT;
                inet_assign_bit(NODEFRAG, sk, val);
                return 0;
        case IP_BIND_ADDRESS_NO_PORT:
                inet_assign_bit(BIND_ADDRESS_NO_PORT, sk, val);
                return 0;
        case IP_TTL:
                if (optlen < 1)
                        return -EINVAL;
                if (val != -1 && (val < 1 || val > 255))
                        return -EINVAL;
                WRITE_ONCE(inet->uc_ttl, val);
                return 0;
        case IP_MINTTL:
                if (optlen < 1)
                        return -EINVAL;
                if (val < 0 || val > 255)
                        return -EINVAL;

                if (val)
                        static_branch_enable(&ip4_min_ttl);

                WRITE_ONCE(inet->min_ttl, val);
                return 0;
        case IP_MULTICAST_TTL:
                if (sk->sk_type == SOCK_STREAM)
                        return -EINVAL;
                if (optlen < 1)
                        return -EINVAL;
                if (val == -1)
                        val = 1;
                if (val < 0 || val > 255)
                        return -EINVAL;
                WRITE_ONCE(inet->mc_ttl, val);
                return 0;
        case IP_MTU_DISCOVER:
                return ip_sock_set_mtu_discover(sk, val);
        case IP_TOS:    /* This sets both TOS and Precedence */
                ip_sock_set_tos(sk, val);
                return 0;
        case IP_LOCAL_PORT_RANGE:
        {
                u16 lo = val;
                u16 hi = val >> 16;

                if (optlen != sizeof(u32))
                        return -EINVAL;
                if (lo != 0 && hi != 0 && lo > hi)
                        return -EINVAL;

                WRITE_ONCE(inet->local_port_range, val);
                return 0;
        }
        }

        err = 0;
        if (needs_rtnl)
                rtnl_lock();
        sockopt_lock_sock(sk);

        switch (optname) {
        case IP_OPTIONS:
        {
                struct ip_options_rcu *old, *opt = NULL;

                if (optlen > 40)
                        goto e_inval;
                err = ip_options_get(sock_net(sk), &opt, optval, optlen);
                if (err)
                        break;
                old = rcu_dereference_protected(inet->inet_opt,
                                                lockdep_sock_is_held(sk));
                if (inet_test_bit(IS_ICSK, sk)) {
                        struct inet_connection_sock *icsk = inet_csk(sk);
#if IS_ENABLED(CONFIG_IPV6)
                        if (sk->sk_family == PF_INET ||
                            (!((1 << sk->sk_state) &
                               (TCPF_LISTEN | TCPF_CLOSE)) &&
                             inet->inet_daddr != LOOPBACK4_IPV6)) {
#endif
                                if (old)
                                        icsk->icsk_ext_hdr_len -= old->opt.optlen;
                                if (opt)
                                        icsk->icsk_ext_hdr_len += opt->opt.optlen;
                                icsk->icsk_sync_mss(sk, icsk->icsk_pmtu_cookie);
#if IS_ENABLED(CONFIG_IPV6)
                        }
#endif
                }
                rcu_assign_pointer(inet->inet_opt, opt);
                if (old)
                        kfree_rcu(old, rcu);
                break;
        }
        case IP_CHECKSUM:
                if (val) {
                        if (!(inet_test_bit(CHECKSUM, sk))) {
                                inet_inc_convert_csum(sk);
                                inet_set_bit(CHECKSUM, sk);
                        }
                } else {
                        if (inet_test_bit(CHECKSUM, sk)) {
                                inet_dec_convert_csum(sk);
                                inet_clear_bit(CHECKSUM, sk);
                        }
                }
                break;
        case IP_UNICAST_IF:
        {
                struct net_device *dev = NULL;
                int ifindex;
                int midx;

                if (optlen != sizeof(int))
                        goto e_inval;

                ifindex = (__force int)ntohl((__force __be32)val);
                if (ifindex == 0) {
                        WRITE_ONCE(inet->uc_index, 0);
                        err = 0;
                        break;
                }

                dev = dev_get_by_index(sock_net(sk), ifindex);
                err = -EADDRNOTAVAIL;
                if (!dev)
                        break;

                midx = l3mdev_master_ifindex(dev);
                dev_put(dev);

                err = -EINVAL;
                if (sk->sk_bound_dev_if && midx != sk->sk_bound_dev_if)
                        break;

                WRITE_ONCE(inet->uc_index, ifindex);
                err = 0;
                break;
        }
        case IP_MULTICAST_IF:
        {
                struct ip_mreqn mreq;
                struct net_device *dev = NULL;
                int midx;

                if (sk->sk_type == SOCK_STREAM)
                        goto e_inval;
                /*
                 *      Check the arguments are allowable
                 */

                if (optlen < sizeof(struct in_addr))
                        goto e_inval;

                err = -EFAULT;
                if (optlen >= sizeof(struct ip_mreqn)) {
                        if (copy_from_sockptr(&mreq, optval, sizeof(mreq)))
                                break;
                } else {
                        memset(&mreq, 0, sizeof(mreq));
                        if (optlen >= sizeof(struct ip_mreq)) {
                                if (copy_from_sockptr(&mreq, optval,
                                                      sizeof(struct ip_mreq)))
                                        break;
                        } else if (optlen >= sizeof(struct in_addr)) {
                                if (copy_from_sockptr(&mreq.imr_address, optval,
                                                      sizeof(struct in_addr)))
                                        break;
                        }
                }

                if (!mreq.imr_ifindex) {
                        if (mreq.imr_address.s_addr == htonl(INADDR_ANY)) {
                                WRITE_ONCE(inet->mc_index, 0);
                                WRITE_ONCE(inet->mc_addr, 0);
                                err = 0;
                                break;
                        }
                        dev = ip_dev_find(sock_net(sk), mreq.imr_address.s_addr);
                        if (dev)
                                mreq.imr_ifindex = dev->ifindex;
                } else
                        dev = dev_get_by_index(sock_net(sk), mreq.imr_ifindex);


                err = -EADDRNOTAVAIL;
                if (!dev)
                        break;

                midx = l3mdev_master_ifindex(dev);

                dev_put(dev);

                err = -EINVAL;
                if (sk->sk_bound_dev_if &&
                    mreq.imr_ifindex != sk->sk_bound_dev_if &&
                    midx != sk->sk_bound_dev_if)
                        break;

                WRITE_ONCE(inet->mc_index, mreq.imr_ifindex);
                WRITE_ONCE(inet->mc_addr, mreq.imr_address.s_addr);
                err = 0;
                break;
        }

        case IP_ADD_MEMBERSHIP:
        case IP_DROP_MEMBERSHIP:
        {
                struct ip_mreqn mreq;

                err = -EPROTO;
                if (inet_test_bit(IS_ICSK, sk))
                        break;

                if (optlen < sizeof(struct ip_mreq))
                        goto e_inval;
                err = -EFAULT;
                if (optlen >= sizeof(struct ip_mreqn)) {
                        if (copy_from_sockptr(&mreq, optval, sizeof(mreq)))
                                break;
                } else {
                        memset(&mreq, 0, sizeof(mreq));
                        if (copy_from_sockptr(&mreq, optval,
                                              sizeof(struct ip_mreq)))
                                break;
                }

                if (optname == IP_ADD_MEMBERSHIP)
                        err = ip_mc_join_group(sk, &mreq);
                else
                        err = ip_mc_leave_group(sk, &mreq);
                break;
        }
        case IP_MSFILTER:
        {
                struct ip_msfilter *msf;

                if (optlen < IP_MSFILTER_SIZE(0))
                        goto e_inval;
                if (optlen > READ_ONCE(net->core.sysctl_optmem_max)) {
                        err = -ENOBUFS;
                        break;
                }
                msf = memdup_sockptr(optval, optlen);
                if (IS_ERR(msf)) {
                        err = PTR_ERR(msf);
                        break;
                }
                /* numsrc >= (1G-4) overflow in 32 bits */
                if (msf->imsf_numsrc >= 0x3ffffffcU ||
                    msf->imsf_numsrc > READ_ONCE(net->ipv4.sysctl_igmp_max_msf)) {
                        kfree(msf);
                        err = -ENOBUFS;
                        break;
                }
                if (IP_MSFILTER_SIZE(msf->imsf_numsrc) > optlen) {
                        kfree(msf);
                        err = -EINVAL;
                        break;
                }
                err = ip_mc_msfilter(sk, msf, 0);
                kfree(msf);
                break;
        }
        case IP_BLOCK_SOURCE:
        case IP_UNBLOCK_SOURCE:
        case IP_ADD_SOURCE_MEMBERSHIP:
        case IP_DROP_SOURCE_MEMBERSHIP:
        {
                struct ip_mreq_source mreqs;
                int omode, add;

                if (optlen != sizeof(struct ip_mreq_source))
                        goto e_inval;
                if (copy_from_sockptr(&mreqs, optval, sizeof(mreqs))) {
                        err = -EFAULT;
                        break;
                }
                if (optname == IP_BLOCK_SOURCE) {
                        omode = MCAST_EXCLUDE;
                        add = 1;
                } else if (optname == IP_UNBLOCK_SOURCE) {
                        omode = MCAST_EXCLUDE;
                        add = 0;
                } else if (optname == IP_ADD_SOURCE_MEMBERSHIP) {
                        struct ip_mreqn mreq;

                        mreq.imr_multiaddr.s_addr = mreqs.imr_multiaddr;
                        mreq.imr_address.s_addr = mreqs.imr_interface;
                        mreq.imr_ifindex = 0;
                        err = ip_mc_join_group_ssm(sk, &mreq, MCAST_INCLUDE);
                        if (err && err != -EADDRINUSE)
                                break;
                        omode = MCAST_INCLUDE;
                        add = 1;
                } else /* IP_DROP_SOURCE_MEMBERSHIP */ {
                        omode = MCAST_INCLUDE;
                        add = 0;
                }
                err = ip_mc_source(add, omode, sk, &mreqs, 0);
                break;
        }
        case MCAST_JOIN_GROUP:
        case MCAST_LEAVE_GROUP:
                if (in_compat_syscall())
                        err = compat_ip_mcast_join_leave(sk, optname, optval,
                                                         optlen);
                else
                        err = ip_mcast_join_leave(sk, optname, optval, optlen);
                break;
        case MCAST_JOIN_SOURCE_GROUP:
        case MCAST_LEAVE_SOURCE_GROUP:
        case MCAST_BLOCK_SOURCE:
        case MCAST_UNBLOCK_SOURCE:
                err = do_mcast_group_source(sk, optname, optval, optlen);
                break;
        case MCAST_MSFILTER:
                if (in_compat_syscall())
                        err = compat_ip_set_mcast_msfilter(sk, optval, optlen);
                else
                        err = ip_set_mcast_msfilter(sk, optval, optlen);
                break;
        case IP_IPSEC_POLICY:
        case IP_XFRM_POLICY:
                err = -EPERM;
                if (!sockopt_ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
                        break;
                err = xfrm_user_policy(sk, optname, optval, optlen);
                break;

        default:
                err = -ENOPROTOOPT;
                break;
        }
        sockopt_release_sock(sk);
        if (needs_rtnl)
                rtnl_unlock();
        return err;

e_inval:
        sockopt_release_sock(sk);
        if (needs_rtnl)
                rtnl_unlock();
        return -EINVAL;
}

/**
 * ipv4_pktinfo_prepare - transfer some info from rtable to skb
 * @sk: socket
 * @skb: buffer
 * @drop_dst: if true, drops skb dst
 *
 * To support IP_CMSG_PKTINFO option, we store rt_iif and specific
 * destination in skb->cb[] before dst drop.
 * This way, receiver doesn't make cache line misses to read rtable.
 */
void ipv4_pktinfo_prepare(const struct sock *sk, struct sk_buff *skb, bool drop_dst)
{
        struct in_pktinfo *pktinfo = PKTINFO_SKB_CB(skb);
        bool prepare = inet_test_bit(PKTINFO, sk) ||
                       ipv6_sk_rxinfo(sk);

        if (prepare && skb_rtable(skb)) {
                /* skb->cb is overloaded: prior to this point it is IP{6}CB
                 * which has interface index (iif) as the first member of the
                 * underlying inet{6}_skb_parm struct. This code then overlays
                 * PKTINFO_SKB_CB and in_pktinfo also has iif as the first
                 * element so the iif is picked up from the prior IPCB. If iif
                 * is the loopback interface, then return the sending interface
                 * (e.g., process binds socket to eth0 for Tx which is
                 * redirected to loopback in the rtable/dst).
                 */
                struct rtable *rt = skb_rtable(skb);
                bool l3slave = ipv4_l3mdev_skb(IPCB(skb)->flags);

                if (pktinfo->ipi_ifindex == LOOPBACK_IFINDEX)
                        pktinfo->ipi_ifindex = inet_iif(skb);
                else if (l3slave && rt && rt->rt_iif)
                        pktinfo->ipi_ifindex = rt->rt_iif;

                pktinfo->ipi_spec_dst.s_addr = fib_compute_spec_dst(skb);
        } else {
                pktinfo->ipi_ifindex = 0;
                pktinfo->ipi_spec_dst.s_addr = 0;
        }
        if (drop_dst)
                skb_dst_drop(skb);
}

int ip_setsockopt(struct sock *sk, int level, int optname, sockptr_t optval,
                unsigned int optlen)
{
        int err;

        if (level != SOL_IP)
                return -ENOPROTOOPT;

        err = do_ip_setsockopt(sk, level, optname, optval, optlen);
#ifdef CONFIG_NETFILTER
        /* we need to exclude all possible ENOPROTOOPTs except default case */
        if (err == -ENOPROTOOPT && optname != IP_HDRINCL &&
                        optname != IP_IPSEC_POLICY &&
                        optname != IP_XFRM_POLICY &&
                        !ip_mroute_opt(optname))
                err = nf_setsockopt(sk, PF_INET, optname, optval, optlen);
#endif
        return err;
}
EXPORT_SYMBOL(ip_setsockopt);

/*
 *      Get the options. Note for future reference. The GET of IP options gets
 *      the _received_ ones. The set sets the _sent_ ones.
 */

static bool getsockopt_needs_rtnl(int optname)
{
        switch (optname) {
        case IP_MSFILTER:
        case MCAST_MSFILTER:
                return true;
        }
        return false;
}

static int ip_get_mcast_msfilter(struct sock *sk, sockptr_t optval,
                                 sockptr_t optlen, int len)
{
        const int size0 = offsetof(struct group_filter, gf_slist_flex);
        struct group_filter gsf;
        int num, gsf_size;
        int err;

        if (len < size0)
                return -EINVAL;
        if (copy_from_sockptr(&gsf, optval, size0))
                return -EFAULT;

        num = gsf.gf_numsrc;
        err = ip_mc_gsfget(sk, &gsf, optval,
                           offsetof(struct group_filter, gf_slist_flex));
        if (err)
                return err;
        if (gsf.gf_numsrc < num)
                num = gsf.gf_numsrc;
        gsf_size = GROUP_FILTER_SIZE(num);
        if (copy_to_sockptr(optlen, &gsf_size, sizeof(int)) ||
            copy_to_sockptr(optval, &gsf, size0))
                return -EFAULT;
        return 0;
}

static int compat_ip_get_mcast_msfilter(struct sock *sk, sockptr_t optval,
                                        sockptr_t optlen, int len)
{
        const int size0 = offsetof(struct compat_group_filter, gf_slist_flex);
        struct compat_group_filter gf32;
        struct group_filter gf;
        int num;
        int err;

        if (len < size0)
                return -EINVAL;
        if (copy_from_sockptr(&gf32, optval, size0))
                return -EFAULT;

        gf.gf_interface = gf32.gf_interface;
        gf.gf_fmode = gf32.gf_fmode;
        num = gf.gf_numsrc = gf32.gf_numsrc;
        gf.gf_group = gf32.gf_group;

        err = ip_mc_gsfget(sk, &gf, optval,
                           offsetof(struct compat_group_filter, gf_slist_flex));
        if (err)
                return err;
        if (gf.gf_numsrc < num)
                num = gf.gf_numsrc;
        len = GROUP_FILTER_SIZE(num) - (sizeof(gf) - sizeof(gf32));
        if (copy_to_sockptr(optlen, &len, sizeof(int)) ||
            copy_to_sockptr_offset(optval, offsetof(struct compat_group_filter, gf_fmode),
                                   &gf.gf_fmode, sizeof(gf.gf_fmode)) ||
            copy_to_sockptr_offset(optval, offsetof(struct compat_group_filter, gf_numsrc),
                                   &gf.gf_numsrc, sizeof(gf.gf_numsrc)))
                return -EFAULT;
        return 0;
}

int do_ip_getsockopt(struct sock *sk, int level, int optname,
                     sockptr_t optval, sockptr_t optlen)
{
        struct inet_sock *inet = inet_sk(sk);
        bool needs_rtnl = getsockopt_needs_rtnl(optname);
        int val, err = 0;
        int len;

        if (level != SOL_IP)
                return -EOPNOTSUPP;

        if (ip_mroute_opt(optname))
                return ip_mroute_getsockopt(sk, optname, optval, optlen);

        if (copy_from_sockptr(&len, optlen, sizeof(int)))
                return -EFAULT;
        if (len < 0)
                return -EINVAL;

        /* Handle options that can be read without locking the socket. */
        switch (optname) {
        case IP_PKTINFO:
                val = inet_test_bit(PKTINFO, sk);
                goto copyval;
        case IP_RECVTTL:
                val = inet_test_bit(TTL, sk);
                goto copyval;
        case IP_RECVTOS:
                val = inet_test_bit(TOS, sk);
                goto copyval;
        case IP_RECVOPTS:
                val = inet_test_bit(RECVOPTS, sk);
                goto copyval;
        case IP_RETOPTS:
                val = inet_test_bit(RETOPTS, sk);
                goto copyval;
        case IP_PASSSEC:
                val = inet_test_bit(PASSSEC, sk);
                goto copyval;
        case IP_RECVORIGDSTADDR:
                val = inet_test_bit(ORIGDSTADDR, sk);
                goto copyval;
        case IP_CHECKSUM:
                val = inet_test_bit(CHECKSUM, sk);
                goto copyval;
        case IP_RECVFRAGSIZE:
                val = inet_test_bit(RECVFRAGSIZE, sk);
                goto copyval;
        case IP_RECVERR:
                val = inet_test_bit(RECVERR, sk);
                goto copyval;
        case IP_RECVERR_RFC4884:
                val = inet_test_bit(RECVERR_RFC4884, sk);
                goto copyval;
        case IP_FREEBIND:
                val = inet_test_bit(FREEBIND, sk);
                goto copyval;
        case IP_HDRINCL:
                val = inet_test_bit(HDRINCL, sk);
                goto copyval;
        case IP_MULTICAST_LOOP:
                val = inet_test_bit(MC_LOOP, sk);
                goto copyval;
        case IP_MULTICAST_ALL:
                val = inet_test_bit(MC_ALL, sk);
                goto copyval;
        case IP_TRANSPARENT:
                val = inet_test_bit(TRANSPARENT, sk);
                goto copyval;
        case IP_NODEFRAG:
                val = inet_test_bit(NODEFRAG, sk);
                goto copyval;
        case IP_BIND_ADDRESS_NO_PORT:
                val = inet_test_bit(BIND_ADDRESS_NO_PORT, sk);
                goto copyval;
        case IP_ROUTER_ALERT:
                val = inet_test_bit(RTALERT, sk);
                goto copyval;
        case IP_TTL:
                val = READ_ONCE(inet->uc_ttl);
                if (val < 0)
                        val = READ_ONCE(sock_net(sk)->ipv4.sysctl_ip_default_ttl);
                goto copyval;
        case IP_MINTTL:
                val = READ_ONCE(inet->min_ttl);
                goto copyval;
        case IP_MULTICAST_TTL:
                val = READ_ONCE(inet->mc_ttl);
                goto copyval;
        case IP_MTU_DISCOVER:
                val = READ_ONCE(inet->pmtudisc);
                goto copyval;
        case IP_TOS:
                val = READ_ONCE(inet->tos);
                goto copyval;
        case IP_OPTIONS:
        {
                unsigned char optbuf[sizeof(struct ip_options)+40];
                struct ip_options *opt = (struct ip_options *)optbuf;
                struct ip_options_rcu *inet_opt;

                rcu_read_lock();
                inet_opt = rcu_dereference(inet->inet_opt);
                opt->optlen = 0;
                if (inet_opt)
                        memcpy(optbuf, &inet_opt->opt,
                               sizeof(struct ip_options) +
                               inet_opt->opt.optlen);
                rcu_read_unlock();

                if (opt->optlen == 0) {
                        len = 0;
                        return copy_to_sockptr(optlen, &len, sizeof(int));
                }

                ip_options_undo(opt);

                len = min_t(unsigned int, len, opt->optlen);
                if (copy_to_sockptr(optlen, &len, sizeof(int)))
                        return -EFAULT;
                if (copy_to_sockptr(optval, opt->__data, len))
                        return -EFAULT;
                return 0;
        }
        case IP_MTU:
        {
                struct dst_entry *dst;
                val = 0;
                dst = sk_dst_get(sk);
                if (dst) {
                        val = dst4_mtu(dst);
                        dst_release(dst);
                }
                if (!val)
                        return -ENOTCONN;
                goto copyval;
        }
        case IP_PKTOPTIONS:
        {
                struct msghdr msg;

                if (sk->sk_type != SOCK_STREAM)
                        return -ENOPROTOOPT;

                if (optval.is_kernel) {
                        msg.msg_control_is_user = false;
                        msg.msg_control = optval.kernel;
                } else {
                        msg.msg_control_is_user = true;
                        msg.msg_control_user = optval.user;
                }
                msg.msg_controllen = len;
                msg.msg_flags = in_compat_syscall() ? MSG_CMSG_COMPAT : 0;

                if (inet_test_bit(PKTINFO, sk)) {
                        struct in_pktinfo info;

                        info.ipi_addr.s_addr = READ_ONCE(inet->inet_rcv_saddr);
                        info.ipi_spec_dst.s_addr = READ_ONCE(inet->inet_rcv_saddr);
                        info.ipi_ifindex = READ_ONCE(inet->mc_index);
                        put_cmsg(&msg, SOL_IP, IP_PKTINFO, sizeof(info), &info);
                }
                if (inet_test_bit(TTL, sk)) {
                        int hlim = READ_ONCE(inet->mc_ttl);

                        put_cmsg(&msg, SOL_IP, IP_TTL, sizeof(hlim), &hlim);
                }
                if (inet_test_bit(TOS, sk)) {
                        int tos = READ_ONCE(inet->rcv_tos);
                        put_cmsg(&msg, SOL_IP, IP_TOS, sizeof(tos), &tos);
                }
                len -= msg.msg_controllen;
                return copy_to_sockptr(optlen, &len, sizeof(int));
        }
        case IP_UNICAST_IF:
                val = (__force int)htonl((__u32) READ_ONCE(inet->uc_index));
                goto copyval;
        case IP_MULTICAST_IF:
        {
                struct in_addr addr;
                len = min_t(unsigned int, len, sizeof(struct in_addr));
                addr.s_addr = READ_ONCE(inet->mc_addr);

                if (copy_to_sockptr(optlen, &len, sizeof(int)))
                        return -EFAULT;
                if (copy_to_sockptr(optval, &addr, len))
                        return -EFAULT;
                return 0;
        }
        case IP_LOCAL_PORT_RANGE:
                val = READ_ONCE(inet->local_port_range);
                goto copyval;
        }

        if (needs_rtnl)
                rtnl_lock();
        sockopt_lock_sock(sk);

        switch (optname) {
        case IP_MSFILTER:
        {
                struct ip_msfilter msf;

                if (len < IP_MSFILTER_SIZE(0)) {
                        err = -EINVAL;
                        goto out;
                }
                if (copy_from_sockptr(&msf, optval, IP_MSFILTER_SIZE(0))) {
                        err = -EFAULT;
                        goto out;
                }
                err = ip_mc_msfget(sk, &msf, optval, optlen);
                goto out;
        }
        case MCAST_MSFILTER:
                if (in_compat_syscall())
                        err = compat_ip_get_mcast_msfilter(sk, optval, optlen,
                                                           len);
                else
                        err = ip_get_mcast_msfilter(sk, optval, optlen, len);
                goto out;
        case IP_PROTOCOL:
                val = inet_sk(sk)->inet_num;
                break;
        default:
                sockopt_release_sock(sk);
                return -ENOPROTOOPT;
        }
        sockopt_release_sock(sk);
copyval:
        if (len < sizeof(int) && len > 0 && val >= 0 && val <= 255) {
                unsigned char ucval = (unsigned char)val;
                len = 1;
                if (copy_to_sockptr(optlen, &len, sizeof(int)))
                        return -EFAULT;
                if (copy_to_sockptr(optval, &ucval, 1))
                        return -EFAULT;
        } else {
                len = min_t(unsigned int, sizeof(int), len);
                if (copy_to_sockptr(optlen, &len, sizeof(int)))
                        return -EFAULT;
                if (copy_to_sockptr(optval, &val, len))
                        return -EFAULT;
        }
        return 0;

out:
        sockopt_release_sock(sk);
        if (needs_rtnl)
                rtnl_unlock();
        return err;
}

int ip_getsockopt(struct sock *sk, int level,
                  int optname, char __user *optval, int __user *optlen)
{
        int err;

        err = do_ip_getsockopt(sk, level, optname,
                               USER_SOCKPTR(optval), USER_SOCKPTR(optlen));

#ifdef CONFIG_NETFILTER
        /* we need to exclude all possible ENOPROTOOPTs except default case */
        if (err == -ENOPROTOOPT && optname != IP_PKTOPTIONS &&
                        !ip_mroute_opt(optname)) {
                int len;

                if (get_user(len, optlen))
                        return -EFAULT;

                err = nf_getsockopt(sk, PF_INET, optname, optval, &len);
                if (err >= 0)
                        err = put_user(len, optlen);
                return err;
        }
#endif
        return err;
}
EXPORT_SYMBOL(ip_getsockopt);