// 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>

  #include <linux/bpfilter.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)
  {
  	char *secdata;

  	u32 seclen, secid;

  	int err;

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

  	if (err)
  		return;
  
  	put_cmsg(msg, SOL_IP, SCM_SECURITY, seclen, secdata);

  	security_release_secctx(secdata, seclen);

  }

  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)

  {

  	struct inet_sock *inet = inet_sk(sk);

  	unsigned int flags = inet->cmsg_flags;

  
  	/* 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, msg, 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->priority = rt_tos2priority(ipc->tos);
  			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(sizeof(*new_ra), GFP_KERNEL) : 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_sk(sk)->recverr_rfc4884)

  			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);

  }

  void ip_local_error(struct sock *sk, int err, __be32 daddr, __be16 port, u32 info)

  {
  	struct inet_sock *inet = inet_sk(sk);
  	struct sock_exterr_skb *serr;
  	struct iphdr *iph;
  	struct sk_buff *skb;
  
  	if (!inet->recverr)
  		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 (!(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_sk(sk)->cmsg_flags)

  			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;
  }

  static void __ip_sock_set_tos(struct sock *sk, int val)
  {
  	if (sk->sk_type == SOCK_STREAM) {
  		val &= ~INET_ECN_MASK;
  		val |= inet_sk(sk)->tos & INET_ECN_MASK;
  	}
  	if (inet_sk(sk)->tos != val) {
  		inet_sk(sk)->tos = val;
  		sk->sk_priority = rt_tos2priority(val);
  		sk_dst_reset(sk);
  	}
  }
  
  void ip_sock_set_tos(struct sock *sk, int val)
  {
  	lock_sock(sk);
  	__ip_sock_set_tos(sk, val);
  	release_sock(sk);
  }
  EXPORT_SYMBOL(ip_sock_set_tos);

  void ip_sock_set_freebind(struct sock *sk)
  {
  	lock_sock(sk);
  	inet_sk(sk)->freebind = true;
  	release_sock(sk);
  }
  EXPORT_SYMBOL(ip_sock_set_freebind);

  void ip_sock_set_recverr(struct sock *sk)
  {
  	lock_sock(sk);
  	inet_sk(sk)->recverr = true;
  	release_sock(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;
  	lock_sock(sk);
  	inet_sk(sk)->pmtudisc = val;
  	release_sock(sk);
  	return 0;
  }
  EXPORT_SYMBOL(ip_sock_set_mtu_discover);

  void ip_sock_set_pktinfo(struct sock *sk)
  {
  	lock_sock(sk);
  	inet_sk(sk)->cmsg_flags |= IP_CMSG_PKTINFO;
  	release_sock(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)
  {
  	int msize = IP_MSFILTER_SIZE(numsrc);
  	struct ip_msfilter *msf;
  	struct sockaddr_in *psin;
  	int err, i;
  
  	msf = kmalloc(msize, 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[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 > 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 > 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);
  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);
  	struct compat_group_filter *gf32;
  	unsigned int n;
  	void *p;
  	int err;
  
  	if (optlen < size0)
  		return -EINVAL;
  	if (optlen > 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 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[n]) > optlen)
  		goto out_free_gsf;

  	/* numsrc >= (4G-140)/128 overflow in 32 bits */
  	err = -ENOBUFS;
  	if (n > 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);

  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);

  }

  static 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;

  	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:

  		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)
  		return ip_ra_control(sk, val ? 1 : 0, NULL);

  	if (ip_mroute_opt(optname))

  		return ip_mroute_setsockopt(sk, optname, optval, optlen);

  
  	err = 0;

  	if (needs_rtnl)
  		rtnl_lock();

  	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->is_icsk) {
  			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_PKTINFO:
  		if (val)
  			inet->cmsg_flags |= IP_CMSG_PKTINFO;
  		else
  			inet->cmsg_flags &= ~IP_CMSG_PKTINFO;
  		break;
  	case IP_RECVTTL:
  		if (val)
  			inet->cmsg_flags |=  IP_CMSG_TTL;
  		else
  			inet->cmsg_flags &= ~IP_CMSG_TTL;
  		break;
  	case IP_RECVTOS:
  		if (val)
  			inet->cmsg_flags |=  IP_CMSG_TOS;
  		else
  			inet->cmsg_flags &= ~IP_CMSG_TOS;
  		break;
  	case IP_RECVOPTS:
  		if (val)
  			inet->cmsg_flags |=  IP_CMSG_RECVOPTS;
  		else
  			inet->cmsg_flags &= ~IP_CMSG_RECVOPTS;
  		break;
  	case IP_RETOPTS:
  		if (val)
  			inet->cmsg_flags |= IP_CMSG_RETOPTS;
  		else
  			inet->cmsg_flags &= ~IP_CMSG_RETOPTS;
  		break;
  	case IP_PASSSEC:
  		if (val)
  			inet->cmsg_flags |= IP_CMSG_PASSSEC;
  		else
  			inet->cmsg_flags &= ~IP_CMSG_PASSSEC;
  		break;

  	case IP_RECVORIGDSTADDR:
  		if (val)
  			inet->cmsg_flags |= IP_CMSG_ORIGDSTADDR;
  		else
  			inet->cmsg_flags &= ~IP_CMSG_ORIGDSTADDR;
  		break;

  	case IP_CHECKSUM:
  		if (val) {
  			if (!(inet->cmsg_flags & IP_CMSG_CHECKSUM)) {
  				inet_inc_convert_csum(sk);
  				inet->cmsg_flags |= IP_CMSG_CHECKSUM;
  			}
  		} else {
  			if (inet->cmsg_flags & IP_CMSG_CHECKSUM) {
  				inet_dec_convert_csum(sk);
  				inet->cmsg_flags &= ~IP_CMSG_CHECKSUM;
  			}
  		}
  		break;

  	case IP_RECVFRAGSIZE:
  		if (sk->sk_type != SOCK_RAW && sk->sk_type != SOCK_DGRAM)
  			goto e_inval;
  		if (val)
  			inet->cmsg_flags |= IP_CMSG_RECVFRAGSIZE;
  		else
  			inet->cmsg_flags &= ~IP_CMSG_RECVFRAGSIZE;
  		break;

  	case IP_TOS:	/* This sets both TOS and Precedence */

  		__ip_sock_set_tos(sk, val);

  		break;
  	case IP_TTL:

  		if (optlen < 1)

  			goto e_inval;

  		if (val != -1 && (val < 1 || val > 255))

  			goto e_inval;
  		inet->uc_ttl = val;
  		break;
  	case IP_HDRINCL:
  		if (sk->sk_type != SOCK_RAW) {
  			err = -ENOPROTOOPT;

  			break;

  		}
  		inet->hdrincl = val ? 1 : 0;
  		break;

  	case IP_NODEFRAG:
  		if (sk->sk_type != SOCK_RAW) {
  			err = -ENOPROTOOPT;
  			break;
  		}
  		inet->nodefrag = val ? 1 : 0;
  		break;

  	case IP_BIND_ADDRESS_NO_PORT:
  		inet->bind_address_no_port = val ? 1 : 0;
  		break;

  	case IP_MTU_DISCOVER:

  		if (val < IP_PMTUDISC_DONT || val > IP_PMTUDISC_OMIT)

  			goto e_inval;
  		inet->pmtudisc = val;
  		break;
  	case IP_RECVERR:
  		inet->recverr = !!val;
  		if (!val)
  			skb_queue_purge(&sk->sk_error_queue);
  		break;

  	case IP_RECVERR_RFC4884:
  		if (val < 0 || val > 1)
  			goto e_inval;
  		inet->recverr_rfc4884 = !!val;
  		break;

  	case IP_MULTICAST_TTL:
  		if (sk->sk_type == SOCK_STREAM)
  			goto e_inval;

  		if (optlen < 1)

  			goto e_inval;

  		if (val == -1)

  			val = 1;
  		if (val < 0 || val > 255)
  			goto e_inval;
  		inet->mc_ttl = val;
  		break;
  	case IP_MULTICAST_LOOP:

  		if (optlen < 1)

  			goto e_inval;
  		inet->mc_loop = !!val;
  		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) {
  			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;
  
  		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)) {

  				inet->mc_index = 0;
  				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;

  		inet->mc_index = mreq.imr_ifindex;
  		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_sk(sk)->is_icsk)
  			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 > 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 > 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_MULTICAST_ALL:
  		if (optlen < 1)
  			goto e_inval;
  		if (val != 0 && val != 1)
  			goto e_inval;
  		inet->mc_all = val;
  		break;

  
  	case IP_FREEBIND:

  		if (optlen < 1)

  			goto e_inval;
  		inet->freebind = !!val;
  		break;
  
  	case IP_IPSEC_POLICY:
  	case IP_XFRM_POLICY:
  		err = -EPERM;

  		if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))

  			break;

  		err = xfrm_user_policy(sk, optname, optval, optlen);

  		break;

  	case IP_TRANSPARENT:

  		if (!!val && !ns_capable(sock_net(sk)->user_ns, CAP_NET_RAW) &&
  		    !ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN)) {

  			err = -EPERM;
  			break;
  		}
  		if (optlen < 1)
  			goto e_inval;
  		inet->transparent = !!val;
  		break;

  	case IP_MINTTL:
  		if (optlen < 1)
  			goto e_inval;
  		if (val < 0 || val > 255)
  			goto e_inval;
  		inet->min_ttl = val;
  		break;

  	default:
  		err = -ENOPROTOOPT;
  		break;

  	}
  	release_sock(sk);

  	if (needs_rtnl)
  		rtnl_unlock();

  	return err;
  
  e_inval:
  	release_sock(sk);

  	if (needs_rtnl)
  		rtnl_unlock();

  	return -EINVAL;
  }

  /**

   * ipv4_pktinfo_prepare - transfer some info from rtable to skb

   * @sk: socket
   * @skb: buffer
   *

   * 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)

  {

  	struct in_pktinfo *pktinfo = PKTINFO_SKB_CB(skb);

  	bool prepare = (inet_sk(sk)->cmsg_flags & IP_CMSG_PKTINFO) ||
  		       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;
  	}

  	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);

  #if IS_ENABLED(CONFIG_BPFILTER_UMH)

  	if (optname >= BPFILTER_IPT_SO_SET_REPLACE &&
  	    optname < BPFILTER_IPT_SET_MAX)

  		err = bpfilter_ip_set_sockopt(sk, optname, optval, optlen);

  #endif

  #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, void __user *optval,
  		int __user *optlen, int len)
  {
  	const int size0 = offsetof(struct group_filter, gf_slist);
  	struct group_filter __user *p = optval;
  	struct group_filter gsf;
  	int num;
  	int err;
  
  	if (len < size0)
  		return -EINVAL;
  	if (copy_from_user(&gsf, p, size0))
  		return -EFAULT;
  
  	num = gsf.gf_numsrc;
  	err = ip_mc_gsfget(sk, &gsf, p->gf_slist);
  	if (err)
  		return err;
  	if (gsf.gf_numsrc < num)
  		num = gsf.gf_numsrc;
  	if (put_user(GROUP_FILTER_SIZE(num), optlen) ||
  	    copy_to_user(p, &gsf, size0))
  		return -EFAULT;
  	return 0;
  }

  static int compat_ip_get_mcast_msfilter(struct sock *sk, void __user *optval,

  		int __user *optlen, int len)

  {
  	const int size0 = offsetof(struct compat_group_filter, gf_slist);
  	struct compat_group_filter __user *p = optval;
  	struct compat_group_filter gf32;
  	struct group_filter gf;

  	int num;

  	int err;

  	if (len < size0)
  		return -EINVAL;

  	if (copy_from_user(&gf32, p, 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, p->gf_slist);

  	if (err)
  		return err;
  	if (gf.gf_numsrc < num)
  		num = gf.gf_numsrc;
  	len = GROUP_FILTER_SIZE(num) - (sizeof(gf) - sizeof(gf32));
  	if (put_user(len, optlen) ||
  	    put_user(gf.gf_fmode, &p->gf_fmode) ||
  	    put_user(gf.gf_numsrc, &p->gf_numsrc))
  		return -EFAULT;
  	return 0;
  }

  static int do_ip_getsockopt(struct sock *sk, int level, int optname,

  			    char __user *optval, int __user *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 (get_user(len, optlen))

  		return -EFAULT;

  	if (len < 0)

  		return -EINVAL;

  	if (needs_rtnl)
  		rtnl_lock();

  	lock_sock(sk);

  	switch (optname) {
  	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;
  
  		inet_opt = rcu_dereference_protected(inet->inet_opt,

  						     lockdep_sock_is_held(sk));

  		opt->optlen = 0;

  		if (inet_opt)
  			memcpy(optbuf, &inet_opt->opt,
  			       sizeof(struct ip_options) +
  			       inet_opt->opt.optlen);

  		release_sock(sk);
  
  		if (opt->optlen == 0)
  			return put_user(0, optlen);
  
  		ip_options_undo(opt);
  
  		len = min_t(unsigned int, len, opt->optlen);
  		if (put_user(len, optlen))
  			return -EFAULT;
  		if (copy_to_user(optval, opt->__data, len))
  			return -EFAULT;
  		return 0;
  	}
  	case IP_PKTINFO:
  		val = (inet->cmsg_flags & IP_CMSG_PKTINFO) != 0;
  		break;
  	case IP_RECVTTL:
  		val = (inet->cmsg_flags & IP_CMSG_TTL) != 0;
  		break;
  	case IP_RECVTOS:
  		val = (inet->cmsg_flags & IP_CMSG_TOS) != 0;
  		break;
  	case IP_RECVOPTS:
  		val = (inet->cmsg_flags & IP_CMSG_RECVOPTS) != 0;
  		break;
  	case IP_RETOPTS:
  		val = (inet->cmsg_flags & IP_CMSG_RETOPTS) != 0;
  		break;
  	case IP_PASSSEC:
  		val = (inet->cmsg_flags & IP_CMSG_PASSSEC) != 0;
  		break;

  	case IP_RECVORIGDSTADDR:
  		val = (inet->cmsg_flags & IP_CMSG_ORIGDSTADDR) != 0;
  		break;

  	case IP_CHECKSUM:
  		val = (inet->cmsg_flags & IP_CMSG_CHECKSUM) != 0;
  		break;

  	case IP_RECVFRAGSIZE:
  		val = (inet->cmsg_flags & IP_CMSG_RECVFRAGSIZE) != 0;
  		break;

  	case IP_TOS:
  		val = inet->tos;
  		break;
  	case IP_TTL:

  	{
  		struct net *net = sock_net(sk);

  		val = (inet->uc_ttl == -1 ?

  		       net->ipv4.sysctl_ip_default_ttl :

  		       inet->uc_ttl);
  		break;

  	}

  	case IP_HDRINCL:
  		val = inet->hdrincl;
  		break;

  	case IP_NODEFRAG:
  		val = inet->nodefrag;
  		break;

  	case IP_BIND_ADDRESS_NO_PORT:
  		val = inet->bind_address_no_port;
  		break;

  	case IP_MTU_DISCOVER:
  		val = inet->pmtudisc;
  		break;
  	case IP_MTU:
  	{
  		struct dst_entry *dst;
  		val = 0;
  		dst = sk_dst_get(sk);
  		if (dst) {
  			val = dst_mtu(dst);
  			dst_release(dst);

  		}

  		if (!val) {

  			release_sock(sk);

  			return -ENOTCONN;

  		}

  		break;
  	}
  	case IP_RECVERR:
  		val = inet->recverr;
  		break;

  	case IP_RECVERR_RFC4884:
  		val = inet->recverr_rfc4884;
  		break;

  	case IP_MULTICAST_TTL:
  		val = inet->mc_ttl;
  		break;
  	case IP_MULTICAST_LOOP:
  		val = inet->mc_loop;
  		break;

  	case IP_UNICAST_IF:
  		val = (__force int)htonl((__u32) inet->uc_index);
  		break;

  	case IP_MULTICAST_IF:
  	{
  		struct in_addr addr;
  		len = min_t(unsigned int, len, sizeof(struct in_addr));
  		addr.s_addr = inet->mc_addr;
  		release_sock(sk);

  		if (put_user(len, optlen))
  			return -EFAULT;
  		if (copy_to_user(optval, &addr, len))
  			return -EFAULT;
  		return 0;
  	}
  	case IP_MSFILTER:
  	{
  		struct ip_msfilter msf;

  
  		if (len < IP_MSFILTER_SIZE(0)) {

  			err = -EINVAL;
  			goto out;

  		}

  		if (copy_from_user(&msf, optval, IP_MSFILTER_SIZE(0))) {

  			err = -EFAULT;
  			goto out;

  		}

  		err = ip_mc_msfget(sk, &msf,
  				   (struct ip_msfilter __user *)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_MULTICAST_ALL:
  		val = inet->mc_all;
  		break;

  	case IP_PKTOPTIONS:
  	{
  		struct msghdr msg;

  		release_sock(sk);

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

  		msg.msg_control_is_user = true;
  		msg.msg_control_user = optval;

  		msg.msg_controllen = len;

  		msg.msg_flags = in_compat_syscall() ? MSG_CMSG_COMPAT : 0;

  		if (inet->cmsg_flags & IP_CMSG_PKTINFO) {
  			struct in_pktinfo info;

  			info.ipi_addr.s_addr = inet->inet_rcv_saddr;
  			info.ipi_spec_dst.s_addr = inet->inet_rcv_saddr;

  			info.ipi_ifindex = inet->mc_index;
  			put_cmsg(&msg, SOL_IP, IP_PKTINFO, sizeof(info), &info);

  		}

  		if (inet->cmsg_flags & IP_CMSG_TTL) {
  			int hlim = inet->mc_ttl;
  			put_cmsg(&msg, SOL_IP, IP_TTL, sizeof(hlim), &hlim);
  		}

  		if (inet->cmsg_flags & IP_CMSG_TOS) {
  			int tos = inet->rcv_tos;
  			put_cmsg(&msg, SOL_IP, IP_TOS, sizeof(tos), &tos);
  		}

  		len -= msg.msg_controllen;
  		return put_user(len, optlen);
  	}
  	case IP_FREEBIND:
  		val = inet->freebind;
  		break;

  	case IP_TRANSPARENT:
  		val = inet->transparent;
  		break;

  	case IP_MINTTL:
  		val = inet->min_ttl;
  		break;

  	default:
  		release_sock(sk);
  		return -ENOPROTOOPT;

  	}
  	release_sock(sk);

  	if (len < sizeof(int) && len > 0 && val >= 0 && val <= 255) {

  		unsigned char ucval = (unsigned char)val;
  		len = 1;

  		if (put_user(len, optlen))

  			return -EFAULT;

  		if (copy_to_user(optval, &ucval, 1))

  			return -EFAULT;
  	} else {
  		len = min_t(unsigned int, sizeof(int), len);

  		if (put_user(len, optlen))

  			return -EFAULT;

  		if (copy_to_user(optval, &val, len))

  			return -EFAULT;
  	}
  	return 0;

  
  out:
  	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, optval, optlen);

  #if IS_ENABLED(CONFIG_BPFILTER_UMH)

  	if (optname >= BPFILTER_IPT_SO_GET_INFO &&
  	    optname < BPFILTER_IPT_GET_MAX)
  		err = bpfilter_ip_get_sockopt(sk, optname, optval, optlen);
  #endif

  #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);