// SPDX-License-Identifier: GPL-2.0-or-later

  /*
   * 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.
   *
   *		"Ping" sockets
   *

   * Based on ipv4/ping.c code.
   *
   * Authors:	Lorenzo Colitti (IPv6 support)
   *		Vasiliy Kulikov / Openwall (IPv4 implementation, for Linux 2.6),
   *		Pavel Kankovsky (IPv4 implementation, for Linux 2.4.32)

   */
  
  #include <net/addrconf.h>
  #include <net/ipv6.h>
  #include <net/ip6_route.h>
  #include <net/protocol.h>
  #include <net/udp.h>
  #include <net/transp_v6.h>

  #include <linux/proc_fs.h>

  #include <net/ping.h>

  /* Compatibility glue so we can support IPv6 when it's compiled as a module */

  static int dummy_ipv6_recv_error(struct sock *sk, struct msghdr *msg, int len,
  				 int *addr_len)

  {
  	return -EAFNOSUPPORT;
  }

  static void dummy_ip6_datagram_recv_ctl(struct sock *sk, struct msghdr *msg,

  				       struct sk_buff *skb)

  {

  }

  static int dummy_icmpv6_err_convert(u8 type, u8 code, int *err)

  {
  	return -EAFNOSUPPORT;
  }

  static void dummy_ipv6_icmp_error(struct sock *sk, struct sk_buff *skb, int err,
  				  __be16 port, u32 info, u8 *payload) {}
  static int dummy_ipv6_chk_addr(struct net *net, const struct in6_addr *addr,
  			       const struct net_device *dev, int strict)

  {
  	return 0;
  }

  static int ping_v6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)

  {
  	struct inet_sock *inet = inet_sk(sk);
  	struct ipv6_pinfo *np = inet6_sk(sk);
  	struct icmp6hdr user_icmph;
  	int addr_type;
  	struct in6_addr *daddr;

  	int oif = 0;

  	struct flowi6 fl6;
  	int err;

  	struct dst_entry *dst;
  	struct rt6_info *rt;
  	struct pingfakehdr pfh;

  	struct ipcm6_cookie ipc6;

  
  	pr_debug("ping_v6_sendmsg(sk=%p,sk->num=%u)
  ", inet, inet->inet_num);
  
  	err = ping_common_sendmsg(AF_INET6, msg, len, &user_icmph,
  				  sizeof(user_icmph));
  	if (err)
  		return err;
  
  	if (msg->msg_name) {

  		DECLARE_SOCKADDR(struct sockaddr_in6 *, u, msg->msg_name);

  		if (msg->msg_namelen < sizeof(*u))

  			return -EINVAL;

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

  		}

  		daddr = &(u->sin6_addr);

  		if (__ipv6_addr_needs_scope_id(ipv6_addr_type(daddr)))
  			oif = u->sin6_scope_id;

  	} else {
  		if (sk->sk_state != TCP_ESTABLISHED)
  			return -EDESTADDRREQ;

  		daddr = &sk->sk_v6_daddr;

  	}

  	if (!oif)
  		oif = sk->sk_bound_dev_if;
  
  	if (!oif)
  		oif = np->sticky_pktinfo.ipi6_ifindex;
  
  	if (!oif && ipv6_addr_is_multicast(daddr))
  		oif = np->mcast_oif;
  	else if (!oif)
  		oif = np->ucast_oif;

  
  	addr_type = ipv6_addr_type(daddr);

  	if ((__ipv6_addr_needs_scope_id(addr_type) && !oif) ||
  	    (addr_type & IPV6_ADDR_MAPPED) ||
  	    (oif && sk->sk_bound_dev_if && oif != sk->sk_bound_dev_if))

  		return -EINVAL;
  
  	/* TODO: use ip6_datagram_send_ctl to get options from cmsg */
  
  	memset(&fl6, 0, sizeof(fl6));
  
  	fl6.flowi6_proto = IPPROTO_ICMPV6;
  	fl6.saddr = np->saddr;
  	fl6.daddr = *daddr;

  	fl6.flowi6_oif = oif;

  	fl6.flowi6_mark = sk->sk_mark;

  	fl6.flowi6_uid = sk->sk_uid;

  	fl6.fl6_icmp_type = user_icmph.icmp6_type;
  	fl6.fl6_icmp_code = user_icmph.icmp6_code;
  	security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));

  	ipcm6_init_sk(&ipc6, np);

  	ipc6.sockc.mark = sk->sk_mark;

  	fl6.flowlabel = ip6_make_flowinfo(ipc6.tclass, fl6.flowlabel);

  	dst = ip6_sk_dst_lookup_flow(sk, &fl6, daddr, false);

  	if (IS_ERR(dst))
  		return PTR_ERR(dst);
  	rt = (struct rt6_info *) dst;

  	if (!fl6.flowi6_oif && ipv6_addr_is_multicast(&fl6.daddr))
  		fl6.flowi6_oif = np->mcast_oif;
  	else if (!fl6.flowi6_oif)
  		fl6.flowi6_oif = np->ucast_oif;
  
  	pfh.icmph.type = user_icmph.icmp6_type;
  	pfh.icmph.code = user_icmph.icmp6_code;
  	pfh.icmph.checksum = 0;
  	pfh.icmph.un.echo.id = inet->inet_sport;
  	pfh.icmph.un.echo.sequence = user_icmph.icmp6_sequence;

  	pfh.msg = msg;

  	pfh.wcheck = 0;
  	pfh.family = AF_INET6;

  	ipc6.hlimit = ip6_sk_dst_hoplimit(np, &fl6, dst);

  	lock_sock(sk);

  	err = ip6_append_data(sk, ping_getfrag, &pfh, len,

  			      0, &ipc6, &fl6, rt,

  			      MSG_DONTWAIT);

  
  	if (err) {

  		ICMP6_INC_STATS(sock_net(sk), rt->rt6i_idev,
  				ICMP6_MIB_OUTERRORS);

  		ip6_flush_pending_frames(sk);
  	} else {

  		icmpv6_push_pending_frames(sk, &fl6,
  					   (struct icmp6hdr *)&pfh.icmph, len);

  	}

  	release_sock(sk);

  	dst_release(dst);

  	if (err)
  		return err;
  
  	return len;

  }

  struct proto pingv6_prot = {
  	.name =		"PINGv6",
  	.owner =	THIS_MODULE,
  	.init =		ping_init_sock,
  	.close =	ping_close,
  	.connect =	ip6_datagram_connect_v6_only,

  	.disconnect =	__udp_disconnect,

  	.setsockopt =	ipv6_setsockopt,
  	.getsockopt =	ipv6_getsockopt,
  	.sendmsg =	ping_v6_sendmsg,
  	.recvmsg =	ping_recvmsg,
  	.bind =		ping_bind,
  	.backlog_rcv =	ping_queue_rcv_skb,
  	.hash =		ping_hash,
  	.unhash =	ping_unhash,
  	.get_port =	ping_get_port,
  	.obj_size =	sizeof(struct raw6_sock),
  };
  EXPORT_SYMBOL_GPL(pingv6_prot);
  
  static struct inet_protosw pingv6_protosw = {
  	.type =      SOCK_DGRAM,
  	.protocol =  IPPROTO_ICMPV6,
  	.prot =      &pingv6_prot,

  	.ops =       &inet6_sockraw_ops,

  	.flags =     INET_PROTOSW_REUSE,
  };

  #ifdef CONFIG_PROC_FS
  static void *ping_v6_seq_start(struct seq_file *seq, loff_t *pos)
  {
  	return ping_seq_start(seq, pos, AF_INET6);
  }

  static int ping_v6_seq_show(struct seq_file *seq, void *v)

  {
  	if (v == SEQ_START_TOKEN) {
  		seq_puts(seq, IPV6_SEQ_DGRAM_HEADER);
  	} else {
  		int bucket = ((struct ping_iter_state *) seq->private)->bucket;
  		struct inet_sock *inet = inet_sk(v);
  		__u16 srcp = ntohs(inet->inet_sport);
  		__u16 destp = ntohs(inet->inet_dport);
  		ip6_dgram_sock_seq_show(seq, v, srcp, destp, bucket);
  	}
  	return 0;
  }

  static const struct seq_operations ping_v6_seq_ops = {
  	.start		= ping_v6_seq_start,
  	.show		= ping_v6_seq_show,
  	.next		= ping_seq_next,
  	.stop		= ping_seq_stop,
  };

  static int __net_init ping_v6_proc_init_net(struct net *net)
  {

  	if (!proc_create_net("icmp6", 0444, net->proc_net, &ping_v6_seq_ops,
  			sizeof(struct ping_iter_state)))

  		return -ENOMEM;
  	return 0;

  }

  static void __net_exit ping_v6_proc_exit_net(struct net *net)

  {

  	remove_proc_entry("icmp6", net->proc_net);

  }
  
  static struct pernet_operations ping_v6_net_ops = {
  	.init = ping_v6_proc_init_net,
  	.exit = ping_v6_proc_exit_net,
  };
  #endif
  
  int __init pingv6_init(void)
  {
  #ifdef CONFIG_PROC_FS
  	int ret = register_pernet_subsys(&ping_v6_net_ops);
  	if (ret)
  		return ret;
  #endif
  	pingv6_ops.ipv6_recv_error = ipv6_recv_error;

  	pingv6_ops.ip6_datagram_recv_common_ctl = ip6_datagram_recv_common_ctl;
  	pingv6_ops.ip6_datagram_recv_specific_ctl =
  		ip6_datagram_recv_specific_ctl;

  	pingv6_ops.icmpv6_err_convert = icmpv6_err_convert;
  	pingv6_ops.ipv6_icmp_error = ipv6_icmp_error;
  	pingv6_ops.ipv6_chk_addr = ipv6_chk_addr;
  	return inet6_register_protosw(&pingv6_protosw);
  }
  
  /* This never gets called because it's not possible to unload the ipv6 module,
   * but just in case.
   */
  void pingv6_exit(void)
  {
  	pingv6_ops.ipv6_recv_error = dummy_ipv6_recv_error;

  	pingv6_ops.ip6_datagram_recv_common_ctl = dummy_ip6_datagram_recv_ctl;
  	pingv6_ops.ip6_datagram_recv_specific_ctl = dummy_ip6_datagram_recv_ctl;

  	pingv6_ops.icmpv6_err_convert = dummy_icmpv6_err_convert;
  	pingv6_ops.ipv6_icmp_error = dummy_ipv6_icmp_error;
  	pingv6_ops.ipv6_chk_addr = dummy_ipv6_chk_addr;
  #ifdef CONFIG_PROC_FS
  	unregister_pernet_subsys(&ping_v6_net_ops);
  #endif
  	inet6_unregister_protosw(&pingv6_protosw);
  }