/* * 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 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include static struct ping_table ping_table; static 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)) { 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); } } static 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 void inet_get_ping_group_range_net(struct net *net, gid_t *low, gid_t *high) { gid_t *data = net->ipv4.sysctl_ping_group_range; unsigned seq; do { seq = read_seqbegin(&sysctl_local_ports.lock); *low = data[0]; *high = data[1]; } while (read_seqretry(&sysctl_local_ports.lock, seq)); } 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) { 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); } static 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; } static 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) { 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, .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; 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); }