--- /dev/null
+/*
+ * 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
+ *
+ *             This program is free software; you can redistribute it and/or
+ *             modify it under the terms of the GNU General Public License
+ *             as published by the Free Software Foundation; either version
+ *             2 of the License, or (at your option) any later version.
+ *
+ * Based on ipv4/udp.c code.
+ *
+ * Authors:    Vasiliy Kulikov / Openwall (for Linux 2.6),
+ *             Pavel Kankovsky (for Linux 2.4.32)
+ *
+ * Pavel gave all rights to bugs to Vasiliy,
+ * none of the bugs are Pavel's now.
+ *
+ */
+
+#include <asm/system.h>
+#include <linux/uaccess.h>
+#include <asm/ioctls.h>
+#include <linux/types.h>
+#include <linux/fcntl.h>
+#include <linux/socket.h>
+#include <linux/sockios.h>
+#include <linux/in.h>
+#include <linux/errno.h>
+#include <linux/timer.h>
+#include <linux/mm.h>
+#include <linux/inet.h>
+#include <linux/netdevice.h>
+#include <net/snmp.h>
+#include <net/ip.h>
+#include <net/ipv6.h>
+#include <net/icmp.h>
+#include <net/protocol.h>
+#include <linux/skbuff.h>
+#include <linux/proc_fs.h>
+#include <net/sock.h>
+#include <net/ping.h>
+#include <net/icmp.h>
+#include <net/udp.h>
+#include <net/route.h>
+#include <net/inet_common.h>
+#include <net/checksum.h>
+
+
+struct ping_table ping_table __read_mostly;
+
+u16 ping_port_rover;
+
+static inline int ping_hashfn(struct net *net, unsigned num, unsigned mask)
+{
+       int res = (num + net_hash_mix(net)) & mask;
+       pr_debug("hash(%d) = %d\n", num, res);
+       return res;
+}
+
+static inline struct hlist_nulls_head *ping_hashslot(struct ping_table *table,
+                                            struct net *net, unsigned num)
+{
+       return &table->hash[ping_hashfn(net, num, PING_HTABLE_MASK)];
+}
+
+static int ping_v4_get_port(struct sock *sk, unsigned short ident)
+{
+       struct hlist_nulls_node *node;
+       struct hlist_nulls_head *hlist;
+       struct inet_sock *isk, *isk2;
+       struct sock *sk2 = NULL;
+
+       isk = inet_sk(sk);
+       write_lock_bh(&ping_table.lock);
+       if (ident == 0) {
+               u32 i;
+               u16 result = ping_port_rover + 1;
+
+               for (i = 0; i < (1L << 16); i++, result++) {
+                       if (!result)
+                               result++; /* avoid zero */
+                       hlist = ping_hashslot(&ping_table, sock_net(sk),
+                                           result);
+                       ping_portaddr_for_each_entry(sk2, node, hlist) {
+                               isk2 = inet_sk(sk2);
+
+                               if (isk2->inet_num == result)
+                                       goto next_port;
+                       }
+
+                       /* found */
+                       ping_port_rover = ident = result;
+                       break;
+next_port:
+                       ;
+               }
+               if (i >= (1L << 16))
+                       goto fail;
+       } else {
+               hlist = ping_hashslot(&ping_table, sock_net(sk), ident);
+               ping_portaddr_for_each_entry(sk2, node, hlist) {
+                       isk2 = inet_sk(sk2);
+
+                       if ((isk2->inet_num == ident) &&
+                           (sk2 != sk) &&
+                           (!sk2->sk_reuse || !sk->sk_reuse))
+                               goto fail;
+               }
+       }
+
+       pr_debug("found port/ident = %d\n", ident);
+       isk->inet_num = ident;
+       if (sk_unhashed(sk)) {
+               pr_debug("was not hashed\n");
+               sock_hold(sk);
+               hlist_nulls_add_head(&sk->sk_nulls_node, hlist);
+               sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
+       }
+       write_unlock_bh(&ping_table.lock);
+       return 0;
+
+fail:
+       write_unlock_bh(&ping_table.lock);
+       return 1;
+}
+
+static void ping_v4_hash(struct sock *sk)
+{
+       pr_debug("ping_v4_hash(sk->port=%u)\n", inet_sk(sk)->inet_num);
+       BUG(); /* "Please do not press this button again." */
+}
+
+static void ping_v4_unhash(struct sock *sk)
+{
+       struct inet_sock *isk = inet_sk(sk);
+       pr_debug("ping_v4_unhash(isk=%p,isk->num=%u)\n", isk, isk->inet_num);
+       if (sk_hashed(sk)) {
+               struct hlist_nulls_head *hslot;
+
+               hslot = ping_hashslot(&ping_table, sock_net(sk), isk->inet_num);
+               write_lock_bh(&ping_table.lock);
+               hlist_nulls_del(&sk->sk_nulls_node);
+               sock_put(sk);
+               isk->inet_num = isk->inet_sport = 0;
+               sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
+               write_unlock_bh(&ping_table.lock);
+       }
+}
+
+struct sock *ping_v4_lookup(struct net *net, u32 saddr, u32 daddr,
+        u16 ident, int dif)
+{
+       struct hlist_nulls_head *hslot = ping_hashslot(&ping_table, net, ident);
+       struct sock *sk = NULL;
+       struct inet_sock *isk;
+       struct hlist_nulls_node *hnode;
+
+       pr_debug("try to find: num = %d, daddr = %ld, dif = %d\n",
+                        (int)ident, (unsigned long)daddr, dif);
+       read_lock_bh(&ping_table.lock);
+
+       ping_portaddr_for_each_entry(sk, hnode, hslot) {
+               isk = inet_sk(sk);
+
+               pr_debug("found: %p: num = %d, daddr = %ld, dif = %d\n", sk,
+                        (int)isk->inet_num, (unsigned long)isk->inet_rcv_saddr,
+                        sk->sk_bound_dev_if);
+
+               pr_debug("iterate\n");
+               if (isk->inet_num != ident)
+                       continue;
+               if (isk->inet_rcv_saddr && isk->inet_rcv_saddr != daddr)
+                       continue;
+               if (sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif)
+                       continue;
+
+               sock_hold(sk);
+               goto exit;
+       }
+
+       sk = NULL;
+exit:
+       read_unlock_bh(&ping_table.lock);
+
+       return sk;
+}
+
+static int ping_init_sock(struct sock *sk)
+{
+       struct net *net = sock_net(sk);
+       gid_t group = current_egid();
+       gid_t range[2];
+       struct group_info *group_info = get_current_groups();
+       int i, j, count = group_info->ngroups;
+
+       inet_get_ping_group_range_net(net, range, range+1);
+       if (range[0] <= group && group <= range[1])
+               return 0;
+
+       for (i = 0; i < group_info->nblocks; i++) {
+               int cp_count = min_t(int, NGROUPS_PER_BLOCK, count);
+
+               for (j = 0; j < cp_count; j++) {
+                       group = group_info->blocks[i][j];
+                       if (range[0] <= group && group <= range[1])
+                               return 0;
+               }
+
+               count -= cp_count;
+       }
+
+       return -EACCES;
+}
+
+static void ping_close(struct sock *sk, long timeout)
+{
+       pr_debug("ping_close(sk=%p,sk->num=%u)\n",
+               inet_sk(sk), inet_sk(sk)->inet_num);
+       pr_debug("isk->refcnt = %d\n", sk->sk_refcnt.counter);
+
+       sk_common_release(sk);
+}
+
+/*
+ * We need our own bind because there are no privileged id's == local ports.
+ * Moreover, we don't allow binding to multi- and broadcast addresses.
+ */
+
+static int ping_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len)
+{
+       struct sockaddr_in *addr = (struct sockaddr_in *)uaddr;
+       struct inet_sock *isk = inet_sk(sk);
+       unsigned short snum;
+       int chk_addr_ret;
+       int err;
+
+       if (addr_len < sizeof(struct sockaddr_in))
+               return -EINVAL;
+
+       pr_debug("ping_v4_bind(sk=%p,sa_addr=%08x,sa_port=%d)\n",
+               sk, addr->sin_addr.s_addr, ntohs(addr->sin_port));
+
+       chk_addr_ret = inet_addr_type(sock_net(sk), addr->sin_addr.s_addr);
+       if (addr->sin_addr.s_addr == INADDR_ANY)
+               chk_addr_ret = RTN_LOCAL;
+
+       if ((sysctl_ip_nonlocal_bind == 0 &&
+           isk->freebind == 0 && isk->transparent == 0 &&
+            chk_addr_ret != RTN_LOCAL) ||
+           chk_addr_ret == RTN_MULTICAST ||
+           chk_addr_ret == RTN_BROADCAST)
+               return -EADDRNOTAVAIL;
+
+       lock_sock(sk);
+
+       err = -EINVAL;
+       if (isk->inet_num != 0)
+               goto out;
+
+       err = -EADDRINUSE;
+       isk->inet_rcv_saddr = isk->inet_saddr = addr->sin_addr.s_addr;
+       snum = ntohs(addr->sin_port);
+       if (ping_v4_get_port(sk, snum) != 0) {
+               isk->inet_saddr = isk->inet_rcv_saddr = 0;
+               goto out;
+       }
+
+       pr_debug("after bind(): num = %d, daddr = %ld, dif = %d\n",
+               (int)isk->inet_num,
+               (unsigned long) isk->inet_rcv_saddr,
+               (int)sk->sk_bound_dev_if);
+
+       err = 0;
+       if (isk->inet_rcv_saddr)
+               sk->sk_userlocks |= SOCK_BINDADDR_LOCK;
+       if (snum)
+               sk->sk_userlocks |= SOCK_BINDPORT_LOCK;
+       isk->inet_sport = htons(isk->inet_num);
+       isk->inet_daddr = 0;
+       isk->inet_dport = 0;
+       sk_dst_reset(sk);
+out:
+       release_sock(sk);
+       pr_debug("ping_v4_bind -> %d\n", err);
+       return err;
+}
+
+/*
+ * Is this a supported type of ICMP message?
+ */
+
+static inline int ping_supported(int type, int code)
+{
+       if (type == ICMP_ECHO && code == 0)
+               return 1;
+       return 0;
+}
+
+/*
+ * This routine is called by the ICMP module when it gets some
+ * sort of error condition.
+ */
+
+static int ping_queue_rcv_skb(struct sock *sk, struct sk_buff *skb);
+
+void ping_err(struct sk_buff *skb, u32 info)
+{
+       struct iphdr *iph = (struct iphdr *)skb->data;
+       struct icmphdr *icmph = (struct icmphdr *)(skb->data+(iph->ihl<<2));
+       struct inet_sock *inet_sock;
+       int type = icmph->type;
+       int code = icmph->code;
+       struct net *net = dev_net(skb->dev);
+       struct sock *sk;
+       int harderr;
+       int err;
+
+       /* We assume the packet has already been checked by icmp_unreach */
+
+       if (!ping_supported(icmph->type, icmph->code))
+               return;
+
+       pr_debug("ping_err(type=%04x,code=%04x,id=%04x,seq=%04x)\n", type,
+               code, ntohs(icmph->un.echo.id), ntohs(icmph->un.echo.sequence));
+
+       sk = ping_v4_lookup(net, iph->daddr, iph->saddr,
+                           ntohs(icmph->un.echo.id), skb->dev->ifindex);
+       if (sk == NULL) {
+               ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
+               pr_debug("no socket, dropping\n");
+               return; /* No socket for error */
+       }
+       pr_debug("err on socket %p\n", sk);
+
+       err = 0;
+       harderr = 0;
+       inet_sock = inet_sk(sk);
+
+       switch (type) {
+       default:
+       case ICMP_TIME_EXCEEDED:
+               err = EHOSTUNREACH;
+               break;
+       case ICMP_SOURCE_QUENCH:
+               /* This is not a real error but ping wants to see it.
+                * Report it with some fake errno. */
+               err = EREMOTEIO;
+               break;
+       case ICMP_PARAMETERPROB:
+               err = EPROTO;
+               harderr = 1;
+               break;
+       case ICMP_DEST_UNREACH:
+               if (code == ICMP_FRAG_NEEDED) { /* Path MTU discovery */
+                       if (inet_sock->pmtudisc != IP_PMTUDISC_DONT) {
+                               err = EMSGSIZE;
+                               harderr = 1;
+                               break;
+                       }
+                       goto out;
+               }
+               err = EHOSTUNREACH;
+               if (code <= NR_ICMP_UNREACH) {
+                       harderr = icmp_err_convert[code].fatal;
+                       err = icmp_err_convert[code].errno;
+               }
+               break;
+       case ICMP_REDIRECT:
+               /* See ICMP_SOURCE_QUENCH */
+               err = EREMOTEIO;
+               break;
+       }
+
+       /*
+        *      RFC1122: OK.  Passes ICMP errors back to application, as per
+        *      4.1.3.3.
+        */
+       if (!inet_sock->recverr) {
+               if (!harderr || sk->sk_state != TCP_ESTABLISHED)
+                       goto out;
+       } else {
+               ip_icmp_error(sk, skb, err, 0 /* no remote port */,
+                        info, (u8 *)icmph);
+       }
+       sk->sk_err = err;
+       sk->sk_error_report(sk);
+out:
+       sock_put(sk);
+}
+
+/*
+ *     Copy and checksum an ICMP Echo packet from user space into a buffer.
+ */
+
+struct pingfakehdr {
+       struct icmphdr icmph;
+       struct iovec *iov;
+       u32 wcheck;
+};
+
+static int ping_getfrag(void *from, char * to,
+                       int offset, int fraglen, int odd, struct sk_buff *skb)
+{
+       struct pingfakehdr *pfh = (struct pingfakehdr *)from;
+
+       if (offset == 0) {
+               if (fraglen < sizeof(struct icmphdr))
+                       BUG();
+               if (csum_partial_copy_fromiovecend(to + sizeof(struct icmphdr),
+                           pfh->iov, 0, fraglen - sizeof(struct icmphdr),
+                           &pfh->wcheck))
+                       return -EFAULT;
+
+               return 0;
+       }
+       if (offset < sizeof(struct icmphdr))
+               BUG();
+       if (csum_partial_copy_fromiovecend
+                       (to, pfh->iov, offset - sizeof(struct icmphdr),
+                        fraglen, &pfh->wcheck))
+               return -EFAULT;
+       return 0;
+}
+
+static int ping_push_pending_frames(struct sock *sk, struct pingfakehdr *pfh, struct flowi4 *fl4)
+{
+       struct sk_buff *skb = skb_peek(&sk->sk_write_queue);
+
+       pfh->wcheck = csum_partial((char *)&pfh->icmph,
+               sizeof(struct icmphdr), pfh->wcheck);
+       pfh->icmph.checksum = csum_fold(pfh->wcheck);
+       memcpy(icmp_hdr(skb), &pfh->icmph, sizeof(struct icmphdr));
+       skb->ip_summed = CHECKSUM_NONE;
+       return ip_push_pending_frames(sk, fl4);
+}
+
+int ping_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
+                size_t len)
+{
+       struct net *net = sock_net(sk);
+       struct flowi4 fl4;
+       struct inet_sock *inet = inet_sk(sk);
+       struct ipcm_cookie ipc;
+       struct icmphdr user_icmph;
+       struct pingfakehdr pfh;
+       struct rtable *rt = NULL;
+       struct ip_options_data opt_copy;
+       int free = 0;
+       u32 saddr, daddr, faddr;
+       u8  tos;
+       int err;
+
+       pr_debug("ping_sendmsg(sk=%p,sk->num=%u)\n", inet, inet->inet_num);
+
+
+       if (len > 0xFFFF)
+               return -EMSGSIZE;
+
+       /*
+        *      Check the flags.
+        */
+
+       /* Mirror BSD error message compatibility */
+       if (msg->msg_flags & MSG_OOB)
+               return -EOPNOTSUPP;
+
+       /*
+        *      Fetch the ICMP header provided by the userland.
+        *      iovec is modified!
+        */
+
+       if (memcpy_fromiovec((u8 *)&user_icmph, msg->msg_iov,
+                            sizeof(struct icmphdr)))
+               return -EFAULT;
+       if (!ping_supported(user_icmph.type, user_icmph.code))
+               return -EINVAL;
+
+       /*
+        *      Get and verify the address.
+        */
+
+       if (msg->msg_name) {
+               struct sockaddr_in *usin = (struct sockaddr_in *)msg->msg_name;
+               if (msg->msg_namelen < sizeof(*usin))
+                       return -EINVAL;
+               if (usin->sin_family != AF_INET)
+                       return -EINVAL;
+               daddr = usin->sin_addr.s_addr;
+               /* no remote port */
+       } else {
+               if (sk->sk_state != TCP_ESTABLISHED)
+                       return -EDESTADDRREQ;
+               daddr = inet->inet_daddr;
+               /* no remote port */
+       }
+
+       ipc.addr = inet->inet_saddr;
+       ipc.opt = NULL;
+       ipc.oif = sk->sk_bound_dev_if;
+       ipc.tx_flags = 0;
+       err = sock_tx_timestamp(sk, &ipc.tx_flags);
+       if (err)
+               return err;
+
+       if (msg->msg_controllen) {
+               err = ip_cmsg_send(sock_net(sk), msg, &ipc);
+               if (err)
+                       return err;
+               if (ipc.opt)
+                       free = 1;
+       }
+       if (!ipc.opt) {
+               struct ip_options_rcu *inet_opt;
+
+               rcu_read_lock();
+               inet_opt = rcu_dereference(inet->inet_opt);
+               if (inet_opt) {
+                       memcpy(&opt_copy, inet_opt,
+                              sizeof(*inet_opt) + inet_opt->opt.optlen);
+                       ipc.opt = &opt_copy.opt;
+               }
+               rcu_read_unlock();
+       }
+
+       saddr = ipc.addr;
+       ipc.addr = faddr = daddr;
+
+       if (ipc.opt && ipc.opt->opt.srr) {
+               if (!daddr)
+                       return -EINVAL;
+               faddr = ipc.opt->opt.faddr;
+       }
+       tos = RT_TOS(inet->tos);
+       if (sock_flag(sk, SOCK_LOCALROUTE) ||
+           (msg->msg_flags & MSG_DONTROUTE) ||
+           (ipc.opt && ipc.opt->opt.is_strictroute)) {
+               tos |= RTO_ONLINK;
+       }
+
+       if (ipv4_is_multicast(daddr)) {
+               if (!ipc.oif)
+                       ipc.oif = inet->mc_index;
+               if (!saddr)
+                       saddr = inet->mc_addr;
+       }
+
+       flowi4_init_output(&fl4, ipc.oif, sk->sk_mark, tos,
+                          RT_SCOPE_UNIVERSE, sk->sk_protocol,
+                          inet_sk_flowi_flags(sk), faddr, saddr, 0, 0);
+
+       security_sk_classify_flow(sk, flowi4_to_flowi(&fl4));
+       rt = ip_route_output_flow(net, &fl4, sk);
+       if (IS_ERR(rt)) {
+               err = PTR_ERR(rt);
+               rt = NULL;
+               if (err == -ENETUNREACH)
+                       IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES);
+               goto out;
+       }
+
+       err = -EACCES;
+       if ((rt->rt_flags & RTCF_BROADCAST) &&
+           !sock_flag(sk, SOCK_BROADCAST))
+               goto out;
+
+       if (msg->msg_flags & MSG_CONFIRM)
+               goto do_confirm;
+back_from_confirm:
+
+       if (!ipc.addr)
+               ipc.addr = fl4.daddr;
+
+       lock_sock(sk);
+
+       pfh.icmph.type = user_icmph.type; /* already checked */
+       pfh.icmph.code = user_icmph.code; /* ditto */
+       pfh.icmph.checksum = 0;
+       pfh.icmph.un.echo.id = inet->inet_sport;
+       pfh.icmph.un.echo.sequence = user_icmph.un.echo.sequence;
+       pfh.iov = msg->msg_iov;
+       pfh.wcheck = 0;
+
+       err = ip_append_data(sk, &fl4, ping_getfrag, &pfh, len,
+                       0, &ipc, &rt, msg->msg_flags);
+       if (err)
+               ip_flush_pending_frames(sk);
+       else
+               err = ping_push_pending_frames(sk, &pfh, &fl4);
+       release_sock(sk);
+
+out:
+       ip_rt_put(rt);
+       if (free)
+               kfree(ipc.opt);
+       if (!err) {
+               icmp_out_count(sock_net(sk), user_icmph.type);
+               return len;
+       }
+       return err;
+
+do_confirm:
+       dst_confirm(&rt->dst);
+       if (!(msg->msg_flags & MSG_PROBE) || len)
+               goto back_from_confirm;
+       err = 0;
+       goto out;
+}
+
+/*
+ *     IOCTL requests applicable to the UDP^H^H^HICMP protocol
+ */
+
+int ping_ioctl(struct sock *sk, int cmd, unsigned long arg)
+{
+       pr_debug("ping_ioctl(sk=%p,sk->num=%u,cmd=%d,arg=%lu)\n",
+               inet_sk(sk), inet_sk(sk)->inet_num, cmd, arg);
+       switch (cmd) {
+       case SIOCOUTQ:
+       case SIOCINQ:
+               return udp_ioctl(sk, cmd, arg);
+       default:
+               return -ENOIOCTLCMD;
+       }
+}
+
+int ping_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
+                size_t len, int noblock, int flags, int *addr_len)
+{
+       struct inet_sock *isk = inet_sk(sk);
+       struct sockaddr_in *sin = (struct sockaddr_in *)msg->msg_name;
+       struct sk_buff *skb;
+       int copied, err;
+
+       pr_debug("ping_recvmsg(sk=%p,sk->num=%u)\n", isk, isk->inet_num);
+
+       if (flags & MSG_OOB)
+               goto out;
+
+       if (addr_len)
+               *addr_len = sizeof(*sin);
+
+       if (flags & MSG_ERRQUEUE)
+               return ip_recv_error(sk, msg, len);
+
+       skb = skb_recv_datagram(sk, flags, noblock, &err);
+       if (!skb)
+               goto out;
+
+       copied = skb->len;
+       if (copied > len) {
+               msg->msg_flags |= MSG_TRUNC;
+               copied = len;
+       }
+
+       /* Don't bother checking the checksum */
+       err = skb_copy_datagram_iovec(skb, 0, msg->msg_iov, copied);
+       if (err)
+               goto done;
+
+       sock_recv_timestamp(msg, sk, skb);
+
+       /* Copy the address. */
+       if (sin) {
+               sin->sin_family = AF_INET;
+               sin->sin_port = 0 /* skb->h.uh->source */;
+               sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
+               memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
+       }
+       if (isk->cmsg_flags)
+               ip_cmsg_recv(msg, skb);
+       err = copied;
+
+done:
+       skb_free_datagram(sk, skb);
+out:
+       pr_debug("ping_recvmsg -> %d\n", err);
+       return err;
+}
+
+static int ping_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
+{
+       pr_debug("ping_queue_rcv_skb(sk=%p,sk->num=%d,skb=%p)\n",
+               inet_sk(sk), inet_sk(sk)->inet_num, skb);
+       if (sock_queue_rcv_skb(sk, skb) < 0) {
+               ICMP_INC_STATS_BH(sock_net(sk), ICMP_MIB_INERRORS);
+               kfree_skb(skb);
+               pr_debug("ping_queue_rcv_skb -> failed\n");
+               return -1;
+       }
+       return 0;
+}
+
+
+/*
+ *     All we need to do is get the socket.
+ */
+
+void ping_rcv(struct sk_buff *skb)
+{
+       struct sock *sk;
+       struct net *net = dev_net(skb->dev);
+       struct iphdr *iph = ip_hdr(skb);
+       struct icmphdr *icmph = icmp_hdr(skb);
+       u32 saddr = iph->saddr;
+       u32 daddr = iph->daddr;
+
+       /* We assume the packet has already been checked by icmp_rcv */
+
+       pr_debug("ping_rcv(skb=%p,id=%04x,seq=%04x)\n",
+               skb, ntohs(icmph->un.echo.id), ntohs(icmph->un.echo.sequence));
+
+       /* Push ICMP header back */
+       skb_push(skb, skb->data - (u8 *)icmph);
+
+       sk = ping_v4_lookup(net, saddr, daddr, ntohs(icmph->un.echo.id),
+                           skb->dev->ifindex);
+       if (sk != NULL) {
+               pr_debug("rcv on socket %p\n", sk);
+               ping_queue_rcv_skb(sk, skb_get(skb));
+               sock_put(sk);
+               return;
+       }
+       pr_debug("no socket, dropping\n");
+
+       /* We're called from icmp_rcv(). kfree_skb() is done there. */
+}
+
+struct proto ping_prot = {
+       .name =         "PING",
+       .owner =        THIS_MODULE,
+       .init =         ping_init_sock,
+       .close =        ping_close,
+       .connect =      ip4_datagram_connect,
+       .disconnect =   udp_disconnect,
+       .ioctl =        ping_ioctl,
+       .setsockopt =   ip_setsockopt,
+       .getsockopt =   ip_getsockopt,
+       .sendmsg =      ping_sendmsg,
+       .recvmsg =      ping_recvmsg,
+       .bind =         ping_bind,
+       .backlog_rcv =  ping_queue_rcv_skb,
+       .hash =         ping_v4_hash,
+       .unhash =       ping_v4_unhash,
+       .get_port =     ping_v4_get_port,
+       .obj_size =     sizeof(struct inet_sock),
+};
+EXPORT_SYMBOL(ping_prot);
+
+#ifdef CONFIG_PROC_FS
+
+static struct sock *ping_get_first(struct seq_file *seq, int start)
+{
+       struct sock *sk;
+       struct ping_iter_state *state = seq->private;
+       struct net *net = seq_file_net(seq);
+
+       for (state->bucket = start; state->bucket < PING_HTABLE_SIZE;
+            ++state->bucket) {
+               struct hlist_nulls_node *node;
+               struct hlist_nulls_head *hslot = &ping_table.hash[state->bucket];
+
+               if (hlist_nulls_empty(hslot))
+                       continue;
+
+               sk_nulls_for_each(sk, node, hslot) {
+                       if (net_eq(sock_net(sk), net))
+                               goto found;
+               }
+       }
+       sk = NULL;
+found:
+       return sk;
+}
+
+static struct sock *ping_get_next(struct seq_file *seq, struct sock *sk)
+{
+       struct ping_iter_state *state = seq->private;
+       struct net *net = seq_file_net(seq);
+
+       do {
+               sk = sk_nulls_next(sk);
+       } while (sk && (!net_eq(sock_net(sk), net)));
+
+       if (!sk)
+               return ping_get_first(seq, state->bucket + 1);
+       return sk;
+}
+
+static struct sock *ping_get_idx(struct seq_file *seq, loff_t pos)
+{
+       struct sock *sk = ping_get_first(seq, 0);
+
+       if (sk)
+               while (pos && (sk = ping_get_next(seq, sk)) != NULL)
+                       --pos;
+       return pos ? NULL : sk;
+}
+
+static void *ping_seq_start(struct seq_file *seq, loff_t *pos)
+{
+       struct ping_iter_state *state = seq->private;
+       state->bucket = 0;
+
+       read_lock_bh(&ping_table.lock);
+
+       return *pos ? ping_get_idx(seq, *pos-1) : SEQ_START_TOKEN;
+}
+
+static void *ping_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+       struct sock *sk;
+
+       if (v == SEQ_START_TOKEN)
+               sk = ping_get_idx(seq, 0);
+       else
+               sk = ping_get_next(seq, v);
+
+       ++*pos;
+       return sk;
+}
+
+static void ping_seq_stop(struct seq_file *seq, void *v)
+{
+       read_unlock_bh(&ping_table.lock);
+}
+
+static void ping_format_sock(struct sock *sp, struct seq_file *f,
+               int bucket, int *len)
+{
+       struct inet_sock *inet = inet_sk(sp);
+       __be32 dest = inet->inet_daddr;
+       __be32 src = inet->inet_rcv_saddr;
+       __u16 destp = ntohs(inet->inet_dport);
+       __u16 srcp = ntohs(inet->inet_sport);
+
+       seq_printf(f, "%5d: %08X:%04X %08X:%04X"
+               " %02X %08X:%08X %02X:%08lX %08X %5d %8d %lu %d %pK %d%n",
+               bucket, src, srcp, dest, destp, sp->sk_state,
+               sk_wmem_alloc_get(sp),
+               sk_rmem_alloc_get(sp),
+               0, 0L, 0, sock_i_uid(sp), 0, sock_i_ino(sp),
+               atomic_read(&sp->sk_refcnt), sp,
+               atomic_read(&sp->sk_drops), len);
+}
+
+static int ping_seq_show(struct seq_file *seq, void *v)
+{
+       if (v == SEQ_START_TOKEN)
+               seq_printf(seq, "%-127s\n",
+                          "  sl  local_address rem_address   st tx_queue "
+                          "rx_queue tr tm->when retrnsmt   uid  timeout "
+                          "inode ref pointer drops");
+       else {
+               struct ping_iter_state *state = seq->private;
+               int len;
+
+               ping_format_sock(v, seq, state->bucket, &len);
+               seq_printf(seq, "%*s\n", 127 - len, "");
+       }
+       return 0;
+}
+
+static const struct seq_operations ping_seq_ops = {
+       .show           = ping_seq_show,
+       .start          = ping_seq_start,
+       .next           = ping_seq_next,
+       .stop           = ping_seq_stop,
+};
+
+static int ping_seq_open(struct inode *inode, struct file *file)
+{
+       return seq_open_net(inode, file, &ping_seq_ops,
+                          sizeof(struct ping_iter_state));
+}
+
+static const struct file_operations ping_seq_fops = {
+       .open           = ping_seq_open,
+       .read           = seq_read,
+       .llseek         = seq_lseek,
+       .release        = seq_release_net,
+};
+
+static int ping_proc_register(struct net *net)
+{
+       struct proc_dir_entry *p;
+       int rc = 0;
+
+       p = proc_net_fops_create(net, "icmp", S_IRUGO, &ping_seq_fops);
+       if (!p)
+               rc = -ENOMEM;
+       return rc;
+}
+
+static void ping_proc_unregister(struct net *net)
+{
+       proc_net_remove(net, "icmp");
+}
+
+
+static int __net_init ping_proc_init_net(struct net *net)
+{
+       return ping_proc_register(net);
+}
+
+static void __net_exit ping_proc_exit_net(struct net *net)
+{
+       ping_proc_unregister(net);
+}
+
+static struct pernet_operations ping_net_ops = {
+       .init = ping_proc_init_net,
+       .exit = ping_proc_exit_net,
+};
+
+int __init ping_proc_init(void)
+{
+       return register_pernet_subsys(&ping_net_ops);
+}
+
+void ping_proc_exit(void)
+{
+       unregister_pernet_subsys(&ping_net_ops);
+}
+
+#endif
+
+void __init ping_init(void)
+{
+       int i;
+
+       for (i = 0; i < PING_HTABLE_SIZE; i++)
+               INIT_HLIST_NULLS_HEAD(&ping_table.hash[i], i);
+       rwlock_init(&ping_table.lock);
+}