udp.c 57.1 KB
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/*
 * 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 User Datagram Protocol (UDP).
 *
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 * Authors:	Ross Biro
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 *		Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
 *		Arnt Gulbrandsen, <agulbra@nvg.unit.no>
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 *		Alan Cox, <alan@lxorguk.ukuu.org.uk>
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 *		Hirokazu Takahashi, <taka@valinux.co.jp>
 *
 * Fixes:
 *		Alan Cox	:	verify_area() calls
 *		Alan Cox	: 	stopped close while in use off icmp
 *					messages. Not a fix but a botch that
 *					for udp at least is 'valid'.
 *		Alan Cox	:	Fixed icmp handling properly
 *		Alan Cox	: 	Correct error for oversized datagrams
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 *		Alan Cox	:	Tidied select() semantics.
 *		Alan Cox	:	udp_err() fixed properly, also now
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 *					select and read wake correctly on errors
 *		Alan Cox	:	udp_send verify_area moved to avoid mem leak
 *		Alan Cox	:	UDP can count its memory
 *		Alan Cox	:	send to an unknown connection causes
 *					an ECONNREFUSED off the icmp, but
 *					does NOT close.
 *		Alan Cox	:	Switched to new sk_buff handlers. No more backlog!
 *		Alan Cox	:	Using generic datagram code. Even smaller and the PEEK
 *					bug no longer crashes it.
 *		Fred Van Kempen	: 	Net2e support for sk->broadcast.
 *		Alan Cox	:	Uses skb_free_datagram
 *		Alan Cox	:	Added get/set sockopt support.
 *		Alan Cox	:	Broadcasting without option set returns EACCES.
 *		Alan Cox	:	No wakeup calls. Instead we now use the callbacks.
 *		Alan Cox	:	Use ip_tos and ip_ttl
 *		Alan Cox	:	SNMP Mibs
 *		Alan Cox	:	MSG_DONTROUTE, and 0.0.0.0 support.
 *		Matt Dillon	:	UDP length checks.
 *		Alan Cox	:	Smarter af_inet used properly.
 *		Alan Cox	:	Use new kernel side addressing.
 *		Alan Cox	:	Incorrect return on truncated datagram receive.
 *	Arnt Gulbrandsen 	:	New udp_send and stuff
 *		Alan Cox	:	Cache last socket
 *		Alan Cox	:	Route cache
 *		Jon Peatfield	:	Minor efficiency fix to sendto().
 *		Mike Shaver	:	RFC1122 checks.
 *		Alan Cox	:	Nonblocking error fix.
 *	Willy Konynenberg	:	Transparent proxying support.
 *		Mike McLagan	:	Routing by source
 *		David S. Miller	:	New socket lookup architecture.
 *					Last socket cache retained as it
 *					does have a high hit rate.
 *		Olaf Kirch	:	Don't linearise iovec on sendmsg.
 *		Andi Kleen	:	Some cleanups, cache destination entry
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 *					for connect.
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 *	Vitaly E. Lavrov	:	Transparent proxy revived after year coma.
 *		Melvin Smith	:	Check msg_name not msg_namelen in sendto(),
 *					return ENOTCONN for unconnected sockets (POSIX)
 *		Janos Farkas	:	don't deliver multi/broadcasts to a different
 *					bound-to-device socket
 *	Hirokazu Takahashi	:	HW checksumming for outgoing UDP
 *					datagrams.
 *	Hirokazu Takahashi	:	sendfile() on UDP works now.
 *		Arnaldo C. Melo :	convert /proc/net/udp to seq_file
 *	YOSHIFUJI Hideaki @USAGI and:	Support IPV6_V6ONLY socket option, which
 *	Alexey Kuznetsov:		allow both IPv4 and IPv6 sockets to bind
 *					a single port at the same time.
 *	Derek Atkins <derek@ihtfp.com>: Add Encapulation Support
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 *	James Chapman		:	Add L2TP encapsulation type.
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 *
 *
 *		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.
 */
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#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/ioctls.h>
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#include <linux/bootmem.h>
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#include <linux/highmem.h>
#include <linux/swap.h>
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#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/module.h>
#include <linux/socket.h>
#include <linux/sockios.h>
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#include <linux/igmp.h>
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#include <linux/in.h>
#include <linux/errno.h>
#include <linux/timer.h>
#include <linux/mm.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
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#include <linux/slab.h>
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#include <net/tcp_states.h>
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#include <linux/skbuff.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
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#include <net/net_namespace.h>
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#include <net/icmp.h>
#include <net/route.h>
#include <net/checksum.h>
#include <net/xfrm.h>
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#include "udp_impl.h"
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struct udp_table udp_table __read_mostly;
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EXPORT_SYMBOL(udp_table);
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long sysctl_udp_mem[3] __read_mostly;
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EXPORT_SYMBOL(sysctl_udp_mem);
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int sysctl_udp_rmem_min __read_mostly;
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EXPORT_SYMBOL(sysctl_udp_rmem_min);
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int sysctl_udp_wmem_min __read_mostly;
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EXPORT_SYMBOL(sysctl_udp_wmem_min);

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atomic_long_t udp_memory_allocated;
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EXPORT_SYMBOL(udp_memory_allocated);

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#define MAX_UDP_PORTS 65536
#define PORTS_PER_CHAIN (MAX_UDP_PORTS / UDP_HTABLE_SIZE_MIN)
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static int udp_lib_lport_inuse(struct net *net, __u16 num,
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			       const struct udp_hslot *hslot,
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			       unsigned long *bitmap,
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			       struct sock *sk,
			       int (*saddr_comp)(const struct sock *sk1,
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						 const struct sock *sk2),
			       unsigned int log)
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{
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	struct sock *sk2;
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	struct hlist_nulls_node *node;
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	sk_nulls_for_each(sk2, node, &hslot->head)
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		if (net_eq(sock_net(sk2), net) &&
		    sk2 != sk &&
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		    (bitmap || udp_sk(sk2)->udp_port_hash == num) &&
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		    (!sk2->sk_reuse || !sk->sk_reuse) &&
		    (!sk2->sk_bound_dev_if || !sk->sk_bound_dev_if ||
		     sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
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		    (*saddr_comp)(sk, sk2)) {
			if (bitmap)
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				__set_bit(udp_sk(sk2)->udp_port_hash >> log,
					  bitmap);
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			else
				return 1;
		}
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	return 0;
}

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/*
 * Note: we still hold spinlock of primary hash chain, so no other writer
 * can insert/delete a socket with local_port == num
 */
static int udp_lib_lport_inuse2(struct net *net, __u16 num,
			       struct udp_hslot *hslot2,
			       struct sock *sk,
			       int (*saddr_comp)(const struct sock *sk1,
						 const struct sock *sk2))
{
	struct sock *sk2;
	struct hlist_nulls_node *node;
	int res = 0;

	spin_lock(&hslot2->lock);
	udp_portaddr_for_each_entry(sk2, node, &hslot2->head)
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		if (net_eq(sock_net(sk2), net) &&
		    sk2 != sk &&
		    (udp_sk(sk2)->udp_port_hash == num) &&
		    (!sk2->sk_reuse || !sk->sk_reuse) &&
		    (!sk2->sk_bound_dev_if || !sk->sk_bound_dev_if ||
		     sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
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		    (*saddr_comp)(sk, sk2)) {
			res = 1;
			break;
		}
	spin_unlock(&hslot2->lock);
	return res;
}

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/**
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 *  udp_lib_get_port  -  UDP/-Lite port lookup for IPv4 and IPv6
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 *
 *  @sk:          socket struct in question
 *  @snum:        port number to look up
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 *  @saddr_comp:  AF-dependent comparison of bound local IP addresses
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 *  @hash2_nulladdr: AF-dependant hash value in secondary hash chains,
 *                   with NULL address
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 */
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int udp_lib_get_port(struct sock *sk, unsigned short snum,
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		       int (*saddr_comp)(const struct sock *sk1,
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					 const struct sock *sk2),
		     unsigned int hash2_nulladdr)
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{
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	struct udp_hslot *hslot, *hslot2;
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	struct udp_table *udptable = sk->sk_prot->h.udp_table;
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	int    error = 1;
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	struct net *net = sock_net(sk);
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	if (!snum) {
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		int low, high, remaining;
		unsigned rand;
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		unsigned short first, last;
		DECLARE_BITMAP(bitmap, PORTS_PER_CHAIN);
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		inet_get_local_port_range(&low, &high);
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		remaining = (high - low) + 1;
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		rand = net_random();
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		first = (((u64)rand * remaining) >> 32) + low;
		/*
		 * force rand to be an odd multiple of UDP_HTABLE_SIZE
		 */
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		rand = (rand | 1) * (udptable->mask + 1);
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		last = first + udptable->mask + 1;
		do {
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			hslot = udp_hashslot(udptable, net, first);
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			bitmap_zero(bitmap, PORTS_PER_CHAIN);
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			spin_lock_bh(&hslot->lock);
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			udp_lib_lport_inuse(net, snum, hslot, bitmap, sk,
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					    saddr_comp, udptable->log);
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			snum = first;
			/*
			 * Iterate on all possible values of snum for this hash.
			 * Using steps of an odd multiple of UDP_HTABLE_SIZE
			 * give us randomization and full range coverage.
			 */
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			do {
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				if (low <= snum && snum <= high &&
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				    !test_bit(snum >> udptable->log, bitmap) &&
				    !inet_is_reserved_local_port(snum))
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					goto found;
				snum += rand;
			} while (snum != first);
			spin_unlock_bh(&hslot->lock);
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		} while (++first != last);
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		goto fail;
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	} else {
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		hslot = udp_hashslot(udptable, net, snum);
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		spin_lock_bh(&hslot->lock);
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		if (hslot->count > 10) {
			int exist;
			unsigned int slot2 = udp_sk(sk)->udp_portaddr_hash ^ snum;

			slot2          &= udptable->mask;
			hash2_nulladdr &= udptable->mask;

			hslot2 = udp_hashslot2(udptable, slot2);
			if (hslot->count < hslot2->count)
				goto scan_primary_hash;

			exist = udp_lib_lport_inuse2(net, snum, hslot2,
						     sk, saddr_comp);
			if (!exist && (hash2_nulladdr != slot2)) {
				hslot2 = udp_hashslot2(udptable, hash2_nulladdr);
				exist = udp_lib_lport_inuse2(net, snum, hslot2,
							     sk, saddr_comp);
			}
			if (exist)
				goto fail_unlock;
			else
				goto found;
		}
scan_primary_hash:
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		if (udp_lib_lport_inuse(net, snum, hslot, NULL, sk,
					saddr_comp, 0))
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			goto fail_unlock;
	}
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found:
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	inet_sk(sk)->inet_num = snum;
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	udp_sk(sk)->udp_port_hash = snum;
	udp_sk(sk)->udp_portaddr_hash ^= snum;
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	if (sk_unhashed(sk)) {
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		sk_nulls_add_node_rcu(sk, &hslot->head);
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		hslot->count++;
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		sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
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		hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash);
		spin_lock(&hslot2->lock);
		hlist_nulls_add_head_rcu(&udp_sk(sk)->udp_portaddr_node,
					 &hslot2->head);
		hslot2->count++;
		spin_unlock(&hslot2->lock);
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	}
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	error = 0;
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fail_unlock:
	spin_unlock_bh(&hslot->lock);
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fail:
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	return error;
}
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EXPORT_SYMBOL(udp_lib_get_port);
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static int ipv4_rcv_saddr_equal(const struct sock *sk1, const struct sock *sk2)
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{
	struct inet_sock *inet1 = inet_sk(sk1), *inet2 = inet_sk(sk2);

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	return 	(!ipv6_only_sock(sk2)  &&
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		 (!inet1->inet_rcv_saddr || !inet2->inet_rcv_saddr ||
		   inet1->inet_rcv_saddr == inet2->inet_rcv_saddr));
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}

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static unsigned int udp4_portaddr_hash(struct net *net, __be32 saddr,
				       unsigned int port)
{
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	return jhash_1word((__force u32)saddr, net_hash_mix(net)) ^ port;
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}

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int udp_v4_get_port(struct sock *sk, unsigned short snum)
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{
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	unsigned int hash2_nulladdr =
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		udp4_portaddr_hash(sock_net(sk), htonl(INADDR_ANY), snum);
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	unsigned int hash2_partial =
		udp4_portaddr_hash(sock_net(sk), inet_sk(sk)->inet_rcv_saddr, 0);

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	/* precompute partial secondary hash */
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	udp_sk(sk)->udp_portaddr_hash = hash2_partial;
	return udp_lib_get_port(sk, snum, ipv4_rcv_saddr_equal, hash2_nulladdr);
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}

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static inline int compute_score(struct sock *sk, struct net *net, __be32 saddr,
			 unsigned short hnum,
			 __be16 sport, __be32 daddr, __be16 dport, int dif)
{
	int score = -1;

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	if (net_eq(sock_net(sk), net) && udp_sk(sk)->udp_port_hash == hnum &&
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			!ipv6_only_sock(sk)) {
		struct inet_sock *inet = inet_sk(sk);

		score = (sk->sk_family == PF_INET ? 1 : 0);
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		if (inet->inet_rcv_saddr) {
			if (inet->inet_rcv_saddr != daddr)
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				return -1;
			score += 2;
		}
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		if (inet->inet_daddr) {
			if (inet->inet_daddr != saddr)
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				return -1;
			score += 2;
		}
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		if (inet->inet_dport) {
			if (inet->inet_dport != sport)
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				return -1;
			score += 2;
		}
		if (sk->sk_bound_dev_if) {
			if (sk->sk_bound_dev_if != dif)
				return -1;
			score += 2;
		}
	}
	return score;
}

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/*
 * In this second variant, we check (daddr, dport) matches (inet_rcv_sadd, inet_num)
 */
#define SCORE2_MAX (1 + 2 + 2 + 2)
static inline int compute_score2(struct sock *sk, struct net *net,
				 __be32 saddr, __be16 sport,
				 __be32 daddr, unsigned int hnum, int dif)
{
	int score = -1;

	if (net_eq(sock_net(sk), net) && !ipv6_only_sock(sk)) {
		struct inet_sock *inet = inet_sk(sk);

		if (inet->inet_rcv_saddr != daddr)
			return -1;
		if (inet->inet_num != hnum)
			return -1;

		score = (sk->sk_family == PF_INET ? 1 : 0);
		if (inet->inet_daddr) {
			if (inet->inet_daddr != saddr)
				return -1;
			score += 2;
		}
		if (inet->inet_dport) {
			if (inet->inet_dport != sport)
				return -1;
			score += 2;
		}
		if (sk->sk_bound_dev_if) {
			if (sk->sk_bound_dev_if != dif)
				return -1;
			score += 2;
		}
	}
	return score;
}


/* called with read_rcu_lock() */
static struct sock *udp4_lib_lookup2(struct net *net,
		__be32 saddr, __be16 sport,
		__be32 daddr, unsigned int hnum, int dif,
		struct udp_hslot *hslot2, unsigned int slot2)
{
	struct sock *sk, *result;
	struct hlist_nulls_node *node;
	int score, badness;

begin:
	result = NULL;
	badness = -1;
	udp_portaddr_for_each_entry_rcu(sk, node, &hslot2->head) {
		score = compute_score2(sk, net, saddr, sport,
				      daddr, hnum, dif);
		if (score > badness) {
			result = sk;
			badness = score;
			if (score == SCORE2_MAX)
				goto exact_match;
		}
	}
	/*
	 * if the nulls value we got at the end of this lookup is
	 * not the expected one, we must restart lookup.
	 * We probably met an item that was moved to another chain.
	 */
	if (get_nulls_value(node) != slot2)
		goto begin;

	if (result) {
exact_match:
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		if (unlikely(!atomic_inc_not_zero_hint(&result->sk_refcnt, 2)))
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			result = NULL;
		else if (unlikely(compute_score2(result, net, saddr, sport,
				  daddr, hnum, dif) < badness)) {
			sock_put(result);
			goto begin;
		}
	}
	return result;
}

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/* UDP is nearly always wildcards out the wazoo, it makes no sense to try
 * harder than this. -DaveM
 */
static struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr,
		__be16 sport, __be32 daddr, __be16 dport,
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		int dif, struct udp_table *udptable)
450
{
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	struct sock *sk, *result;
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	struct hlist_nulls_node *node;
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	unsigned short hnum = ntohs(dport);
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	unsigned int hash2, slot2, slot = udp_hashfn(net, hnum, udptable->mask);
	struct udp_hslot *hslot2, *hslot = &udptable->hash[slot];
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	int score, badness;
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	rcu_read_lock();
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	if (hslot->count > 10) {
		hash2 = udp4_portaddr_hash(net, daddr, hnum);
		slot2 = hash2 & udptable->mask;
		hslot2 = &udptable->hash2[slot2];
		if (hslot->count < hslot2->count)
			goto begin;

		result = udp4_lib_lookup2(net, saddr, sport,
					  daddr, hnum, dif,
					  hslot2, slot2);
		if (!result) {
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			hash2 = udp4_portaddr_hash(net, htonl(INADDR_ANY), hnum);
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			slot2 = hash2 & udptable->mask;
			hslot2 = &udptable->hash2[slot2];
			if (hslot->count < hslot2->count)
				goto begin;

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			result = udp4_lib_lookup2(net, saddr, sport,
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						  htonl(INADDR_ANY), hnum, dif,
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						  hslot2, slot2);
		}
		rcu_read_unlock();
		return result;
	}
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begin:
	result = NULL;
	badness = -1;
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	sk_nulls_for_each_rcu(sk, node, &hslot->head) {
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		score = compute_score(sk, net, saddr, hnum, sport,
				      daddr, dport, dif);
		if (score > badness) {
			result = sk;
			badness = score;
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		}
	}
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	/*
	 * if the nulls value we got at the end of this lookup is
	 * not the expected one, we must restart lookup.
	 * We probably met an item that was moved to another chain.
	 */
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	if (get_nulls_value(node) != slot)
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		goto begin;

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	if (result) {
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		if (unlikely(!atomic_inc_not_zero_hint(&result->sk_refcnt, 2)))
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			result = NULL;
		else if (unlikely(compute_score(result, net, saddr, hnum, sport,
				  daddr, dport, dif) < badness)) {
			sock_put(result);
			goto begin;
		}
	}
	rcu_read_unlock();
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	return result;
}

515 516
static inline struct sock *__udp4_lib_lookup_skb(struct sk_buff *skb,
						 __be16 sport, __be16 dport,
517
						 struct udp_table *udptable)
518
{
519
	struct sock *sk;
520 521
	const struct iphdr *iph = ip_hdr(skb);

522 523 524
	if (unlikely(sk = skb_steal_sock(skb)))
		return sk;
	else
E
Eric Dumazet 已提交
525
		return __udp4_lib_lookup(dev_net(skb_dst(skb)->dev), iph->saddr, sport,
526 527
					 iph->daddr, dport, inet_iif(skb),
					 udptable);
528 529
}

530 531 532
struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
			     __be32 daddr, __be16 dport, int dif)
{
533
	return __udp4_lib_lookup(net, saddr, sport, daddr, dport, dif, &udp_table);
534 535 536
}
EXPORT_SYMBOL_GPL(udp4_lib_lookup);

537
static inline struct sock *udp_v4_mcast_next(struct net *net, struct sock *sk,
538 539 540 541
					     __be16 loc_port, __be32 loc_addr,
					     __be16 rmt_port, __be32 rmt_addr,
					     int dif)
{
542
	struct hlist_nulls_node *node;
543 544 545
	struct sock *s = sk;
	unsigned short hnum = ntohs(loc_port);

546
	sk_nulls_for_each_from(s, node) {
547 548
		struct inet_sock *inet = inet_sk(s);

549 550 551 552 553 554 555
		if (!net_eq(sock_net(s), net) ||
		    udp_sk(s)->udp_port_hash != hnum ||
		    (inet->inet_daddr && inet->inet_daddr != rmt_addr) ||
		    (inet->inet_dport != rmt_port && inet->inet_dport) ||
		    (inet->inet_rcv_saddr &&
		     inet->inet_rcv_saddr != loc_addr) ||
		    ipv6_only_sock(s) ||
556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577
		    (s->sk_bound_dev_if && s->sk_bound_dev_if != dif))
			continue;
		if (!ip_mc_sf_allow(s, loc_addr, rmt_addr, dif))
			continue;
		goto found;
	}
	s = NULL;
found:
	return s;
}

/*
 * This routine is called by the ICMP module when it gets some
 * sort of error condition.  If err < 0 then the socket should
 * be closed and the error returned to the user.  If err > 0
 * it's just the icmp type << 8 | icmp code.
 * Header points to the ip header of the error packet. We move
 * on past this. Then (as it used to claim before adjustment)
 * header points to the first 8 bytes of the udp header.  We need
 * to find the appropriate port.
 */

578
void __udp4_lib_err(struct sk_buff *skb, u32 info, struct udp_table *udptable)
579 580
{
	struct inet_sock *inet;
E
Eric Dumazet 已提交
581 582
	struct iphdr *iph = (struct iphdr *)skb->data;
	struct udphdr *uh = (struct udphdr *)(skb->data+(iph->ihl<<2));
583 584 585 586 587
	const int type = icmp_hdr(skb)->type;
	const int code = icmp_hdr(skb)->code;
	struct sock *sk;
	int harderr;
	int err;
588
	struct net *net = dev_net(skb->dev);
589

590
	sk = __udp4_lib_lookup(net, iph->daddr, uh->dest,
591 592
			iph->saddr, uh->source, skb->dev->ifindex, udptable);
	if (sk == NULL) {
593
		ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635
		return;	/* No socket for error */
	}

	err = 0;
	harderr = 0;
	inet = inet_sk(sk);

	switch (type) {
	default:
	case ICMP_TIME_EXCEEDED:
		err = EHOSTUNREACH;
		break;
	case ICMP_SOURCE_QUENCH:
		goto out;
	case ICMP_PARAMETERPROB:
		err = EPROTO;
		harderr = 1;
		break;
	case ICMP_DEST_UNREACH:
		if (code == ICMP_FRAG_NEEDED) { /* Path MTU discovery */
			if (inet->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;
	}

	/*
	 *      RFC1122: OK.  Passes ICMP errors back to application, as per
	 *	4.1.3.3.
	 */
	if (!inet->recverr) {
		if (!harderr || sk->sk_state != TCP_ESTABLISHED)
			goto out;
636
	} else
E
Eric Dumazet 已提交
637
		ip_icmp_error(sk, skb, err, uh->dest, info, (u8 *)(uh+1));
638

639 640 641 642 643 644 645 646
	sk->sk_err = err;
	sk->sk_error_report(sk);
out:
	sock_put(sk);
}

void udp_err(struct sk_buff *skb, u32 info)
{
647
	__udp4_lib_err(skb, info, &udp_table);
648 649 650 651 652
}

/*
 * Throw away all pending data and cancel the corking. Socket is locked.
 */
653
void udp_flush_pending_frames(struct sock *sk)
654 655 656 657 658 659 660 661 662
{
	struct udp_sock *up = udp_sk(sk);

	if (up->pending) {
		up->len = 0;
		up->pending = 0;
		ip_flush_pending_frames(sk);
	}
}
663
EXPORT_SYMBOL(udp_flush_pending_frames);
664 665

/**
H
Herbert Xu 已提交
666
 * 	udp4_hwcsum  -  handle outgoing HW checksumming
667 668
 * 	@skb: 	sk_buff containing the filled-in UDP header
 * 	        (checksum field must be zeroed out)
H
Herbert Xu 已提交
669 670
 *	@src:	source IP address
 *	@dst:	destination IP address
671
 */
H
Herbert Xu 已提交
672
static void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst)
673 674
{
	struct udphdr *uh = udp_hdr(skb);
H
Herbert Xu 已提交
675 676 677 678
	struct sk_buff *frags = skb_shinfo(skb)->frag_list;
	int offset = skb_transport_offset(skb);
	int len = skb->len - offset;
	int hlen = len;
679 680
	__wsum csum = 0;

H
Herbert Xu 已提交
681
	if (!frags) {
682 683 684 685 686
		/*
		 * Only one fragment on the socket.
		 */
		skb->csum_start = skb_transport_header(skb) - skb->head;
		skb->csum_offset = offsetof(struct udphdr, check);
H
Herbert Xu 已提交
687 688
		uh->check = ~csum_tcpudp_magic(src, dst, len,
					       IPPROTO_UDP, 0);
689 690 691 692 693 694
	} else {
		/*
		 * HW-checksum won't work as there are two or more
		 * fragments on the socket so that all csums of sk_buffs
		 * should be together
		 */
H
Herbert Xu 已提交
695 696 697 698
		do {
			csum = csum_add(csum, frags->csum);
			hlen -= frags->len;
		} while ((frags = frags->next));
699

H
Herbert Xu 已提交
700
		csum = skb_checksum(skb, offset, hlen, csum);
701 702 703 704 705 706 707 708
		skb->ip_summed = CHECKSUM_NONE;

		uh->check = csum_tcpudp_magic(src, dst, len, IPPROTO_UDP, csum);
		if (uh->check == 0)
			uh->check = CSUM_MANGLED_0;
	}
}

H
Herbert Xu 已提交
709
static int udp_send_skb(struct sk_buff *skb, __be32 daddr, __be32 dport)
710
{
H
Herbert Xu 已提交
711
	struct sock *sk = skb->sk;
712 713
	struct inet_sock *inet = inet_sk(sk);
	struct udphdr *uh;
H
Herbert Xu 已提交
714
	struct rtable *rt = (struct rtable *)skb_dst(skb);
715 716
	int err = 0;
	int is_udplite = IS_UDPLITE(sk);
H
Herbert Xu 已提交
717 718
	int offset = skb_transport_offset(skb);
	int len = skb->len - offset;
719 720 721 722 723 724
	__wsum csum = 0;

	/*
	 * Create a UDP header
	 */
	uh = udp_hdr(skb);
H
Herbert Xu 已提交
725 726 727
	uh->source = inet->inet_sport;
	uh->dest = dport;
	uh->len = htons(len);
728 729 730
	uh->check = 0;

	if (is_udplite)  				 /*     UDP-Lite      */
H
Herbert Xu 已提交
731
		csum = udplite_csum(skb);
732 733 734 735 736 737 738 739

	else if (sk->sk_no_check == UDP_CSUM_NOXMIT) {   /* UDP csum disabled */

		skb->ip_summed = CHECKSUM_NONE;
		goto send;

	} else if (skb->ip_summed == CHECKSUM_PARTIAL) { /* UDP hardware csum */

H
Herbert Xu 已提交
740
		udp4_hwcsum(skb, rt->rt_src, daddr);
741 742
		goto send;

H
Herbert Xu 已提交
743 744
	} else
		csum = udp_csum(skb);
745 746

	/* add protocol-dependent pseudo-header */
H
Herbert Xu 已提交
747
	uh->check = csum_tcpudp_magic(rt->rt_src, daddr, len,
E
Eric Dumazet 已提交
748
				      sk->sk_protocol, csum);
749 750 751 752
	if (uh->check == 0)
		uh->check = CSUM_MANGLED_0;

send:
H
Herbert Xu 已提交
753
	err = ip_send_skb(skb);
E
Eric Dumazet 已提交
754 755 756 757 758 759 760 761 762
	if (err) {
		if (err == -ENOBUFS && !inet->recverr) {
			UDP_INC_STATS_USER(sock_net(sk),
					   UDP_MIB_SNDBUFERRORS, is_udplite);
			err = 0;
		}
	} else
		UDP_INC_STATS_USER(sock_net(sk),
				   UDP_MIB_OUTDATAGRAMS, is_udplite);
H
Herbert Xu 已提交
763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780
	return err;
}

/*
 * Push out all pending data as one UDP datagram. Socket is locked.
 */
static int udp_push_pending_frames(struct sock *sk)
{
	struct udp_sock  *up = udp_sk(sk);
	struct inet_sock *inet = inet_sk(sk);
	struct flowi *fl = &inet->cork.fl;
	struct sk_buff *skb;
	int err = 0;

	skb = ip_finish_skb(sk);
	if (!skb)
		goto out;

781
	err = udp_send_skb(skb, fl->fl4_dst, fl->fl4_dport);
H
Herbert Xu 已提交
782

783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804
out:
	up->len = 0;
	up->pending = 0;
	return err;
}

int udp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
		size_t len)
{
	struct inet_sock *inet = inet_sk(sk);
	struct udp_sock *up = udp_sk(sk);
	int ulen = len;
	struct ipcm_cookie ipc;
	struct rtable *rt = NULL;
	int free = 0;
	int connected = 0;
	__be32 daddr, faddr, saddr;
	__be16 dport;
	u8  tos;
	int err, is_udplite = IS_UDPLITE(sk);
	int corkreq = up->corkflag || msg->msg_flags&MSG_MORE;
	int (*getfrag)(void *, char *, int, int, int, struct sk_buff *);
H
Herbert Xu 已提交
805
	struct sk_buff *skb;
806 807 808 809 810 811 812 813

	if (len > 0xFFFF)
		return -EMSGSIZE;

	/*
	 *	Check the flags.
	 */

E
Eric Dumazet 已提交
814
	if (msg->msg_flags & MSG_OOB) /* Mirror BSD error message compatibility */
815 816 817
		return -EOPNOTSUPP;

	ipc.opt = NULL;
818
	ipc.tx_flags = 0;
819

H
Herbert Xu 已提交
820 821
	getfrag = is_udplite ? udplite_getfrag : ip_generic_getfrag;

822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842
	if (up->pending) {
		/*
		 * There are pending frames.
		 * The socket lock must be held while it's corked.
		 */
		lock_sock(sk);
		if (likely(up->pending)) {
			if (unlikely(up->pending != AF_INET)) {
				release_sock(sk);
				return -EINVAL;
			}
			goto do_append_data;
		}
		release_sock(sk);
	}
	ulen += sizeof(struct udphdr);

	/*
	 *	Get and verify the address.
	 */
	if (msg->msg_name) {
E
Eric Dumazet 已提交
843
		struct sockaddr_in * usin = (struct sockaddr_in *)msg->msg_name;
844 845 846 847 848 849 850 851 852 853 854 855 856 857
		if (msg->msg_namelen < sizeof(*usin))
			return -EINVAL;
		if (usin->sin_family != AF_INET) {
			if (usin->sin_family != AF_UNSPEC)
				return -EAFNOSUPPORT;
		}

		daddr = usin->sin_addr.s_addr;
		dport = usin->sin_port;
		if (dport == 0)
			return -EINVAL;
	} else {
		if (sk->sk_state != TCP_ESTABLISHED)
			return -EDESTADDRREQ;
E
Eric Dumazet 已提交
858 859
		daddr = inet->inet_daddr;
		dport = inet->inet_dport;
860 861 862 863 864
		/* Open fast path for connected socket.
		   Route will not be used, if at least one option is set.
		 */
		connected = 1;
	}
E
Eric Dumazet 已提交
865
	ipc.addr = inet->inet_saddr;
866 867

	ipc.oif = sk->sk_bound_dev_if;
868
	err = sock_tx_timestamp(sk, &ipc.tx_flags);
869 870
	if (err)
		return err;
871
	if (msg->msg_controllen) {
872
		err = ip_cmsg_send(sock_net(sk), msg, &ipc);
873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907
		if (err)
			return err;
		if (ipc.opt)
			free = 1;
		connected = 0;
	}
	if (!ipc.opt)
		ipc.opt = inet->opt;

	saddr = ipc.addr;
	ipc.addr = faddr = daddr;

	if (ipc.opt && ipc.opt->srr) {
		if (!daddr)
			return -EINVAL;
		faddr = ipc.opt->faddr;
		connected = 0;
	}
	tos = RT_TOS(inet->tos);
	if (sock_flag(sk, SOCK_LOCALROUTE) ||
	    (msg->msg_flags & MSG_DONTROUTE) ||
	    (ipc.opt && ipc.opt->is_strictroute)) {
		tos |= RTO_ONLINK;
		connected = 0;
	}

	if (ipv4_is_multicast(daddr)) {
		if (!ipc.oif)
			ipc.oif = inet->mc_index;
		if (!saddr)
			saddr = inet->mc_addr;
		connected = 0;
	}

	if (connected)
E
Eric Dumazet 已提交
908
		rt = (struct rtable *)sk_dst_check(sk, 0);
909 910

	if (rt == NULL) {
911 912 913 914 915 916 917 918 919 920 921
		struct flowi4 fl4 = {
			.flowi4_oif = ipc.oif,
			.flowi4_mark = sk->sk_mark,
			.daddr = faddr,
			.saddr = saddr,
			.flowi4_tos = tos,
			.flowi4_proto = sk->sk_protocol,
			.flowi4_flags = (inet_sk_flowi_flags(sk) |
					 FLOWI_FLAG_CAN_SLEEP),
			.uli.ports.sport = inet->inet_sport,
			.uli.ports.dport = dport,
D
David S. Miller 已提交
922
		};
923 924
		struct net *net = sock_net(sk);

925 926
		security_sk_classify_flow(sk, flowi4_to_flowi(&fl4));
		rt = ip_route_output_flow(net, &fl4, sk);
927 928
		if (IS_ERR(rt)) {
			err = PTR_ERR(rt);
929
			rt = NULL;
930
			if (err == -ENETUNREACH)
931
				IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES);
932 933 934 935 936 937 938 939
			goto out;
		}

		err = -EACCES;
		if ((rt->rt_flags & RTCF_BROADCAST) &&
		    !sock_flag(sk, SOCK_BROADCAST))
			goto out;
		if (connected)
940
			sk_dst_set(sk, dst_clone(&rt->dst));
941 942 943 944 945 946 947 948 949 950
	}

	if (msg->msg_flags&MSG_CONFIRM)
		goto do_confirm;
back_from_confirm:

	saddr = rt->rt_src;
	if (!ipc.addr)
		daddr = ipc.addr = rt->rt_dst;

H
Herbert Xu 已提交
951 952 953 954 955 956 957 958 959 960 961
	/* Lockless fast path for the non-corking case. */
	if (!corkreq) {
		skb = ip_make_skb(sk, getfrag, msg->msg_iov, ulen,
				  sizeof(struct udphdr), &ipc, &rt,
				  msg->msg_flags);
		err = PTR_ERR(skb);
		if (skb && !IS_ERR(skb))
			err = udp_send_skb(skb, daddr, dport);
		goto out;
	}

962 963 964 965 966 967 968 969 970 971 972 973 974 975
	lock_sock(sk);
	if (unlikely(up->pending)) {
		/* The socket is already corked while preparing it. */
		/* ... which is an evident application bug. --ANK */
		release_sock(sk);

		LIMIT_NETDEBUG(KERN_DEBUG "udp cork app bug 2\n");
		err = -EINVAL;
		goto out;
	}
	/*
	 *	Now cork the socket to pend data.
	 */
	inet->cork.fl.fl4_dst = daddr;
976
	inet->cork.fl.fl4_dport = dport;
977
	inet->cork.fl.fl4_src = saddr;
978
	inet->cork.fl.fl4_sport = inet->inet_sport;
979 980 981 982 983
	up->pending = AF_INET;

do_append_data:
	up->len += ulen;
	err = ip_append_data(sk, getfrag, msg->msg_iov, ulen,
984
			sizeof(struct udphdr), &ipc, &rt,
985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007
			corkreq ? msg->msg_flags|MSG_MORE : msg->msg_flags);
	if (err)
		udp_flush_pending_frames(sk);
	else if (!corkreq)
		err = udp_push_pending_frames(sk);
	else if (unlikely(skb_queue_empty(&sk->sk_write_queue)))
		up->pending = 0;
	release_sock(sk);

out:
	ip_rt_put(rt);
	if (free)
		kfree(ipc.opt);
	if (!err)
		return len;
	/*
	 * ENOBUFS = no kernel mem, SOCK_NOSPACE = no sndbuf space.  Reporting
	 * ENOBUFS might not be good (it's not tunable per se), but otherwise
	 * we don't have a good statistic (IpOutDiscards but it can be too many
	 * things).  We could add another new stat but at least for now that
	 * seems like overkill.
	 */
	if (err == -ENOBUFS || test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)) {
1008 1009
		UDP_INC_STATS_USER(sock_net(sk),
				UDP_MIB_SNDBUFERRORS, is_udplite);
1010 1011 1012 1013
	}
	return err;

do_confirm:
1014
	dst_confirm(&rt->dst);
1015 1016 1017 1018 1019
	if (!(msg->msg_flags&MSG_PROBE) || len)
		goto back_from_confirm;
	err = 0;
	goto out;
}
E
Eric Dumazet 已提交
1020
EXPORT_SYMBOL(udp_sendmsg);
1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069

int udp_sendpage(struct sock *sk, struct page *page, int offset,
		 size_t size, int flags)
{
	struct udp_sock *up = udp_sk(sk);
	int ret;

	if (!up->pending) {
		struct msghdr msg = {	.msg_flags = flags|MSG_MORE };

		/* Call udp_sendmsg to specify destination address which
		 * sendpage interface can't pass.
		 * This will succeed only when the socket is connected.
		 */
		ret = udp_sendmsg(NULL, sk, &msg, 0);
		if (ret < 0)
			return ret;
	}

	lock_sock(sk);

	if (unlikely(!up->pending)) {
		release_sock(sk);

		LIMIT_NETDEBUG(KERN_DEBUG "udp cork app bug 3\n");
		return -EINVAL;
	}

	ret = ip_append_page(sk, page, offset, size, flags);
	if (ret == -EOPNOTSUPP) {
		release_sock(sk);
		return sock_no_sendpage(sk->sk_socket, page, offset,
					size, flags);
	}
	if (ret < 0) {
		udp_flush_pending_frames(sk);
		goto out;
	}

	up->len += size;
	if (!(up->corkflag || (flags&MSG_MORE)))
		ret = udp_push_pending_frames(sk);
	if (!ret)
		ret = size;
out:
	release_sock(sk);
	return ret;
}

E
Eric Dumazet 已提交
1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090

/**
 *	first_packet_length	- return length of first packet in receive queue
 *	@sk: socket
 *
 *	Drops all bad checksum frames, until a valid one is found.
 *	Returns the length of found skb, or 0 if none is found.
 */
static unsigned int first_packet_length(struct sock *sk)
{
	struct sk_buff_head list_kill, *rcvq = &sk->sk_receive_queue;
	struct sk_buff *skb;
	unsigned int res;

	__skb_queue_head_init(&list_kill);

	spin_lock_bh(&rcvq->lock);
	while ((skb = skb_peek(rcvq)) != NULL &&
		udp_lib_checksum_complete(skb)) {
		UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS,
				 IS_UDPLITE(sk));
E
Eric Dumazet 已提交
1091
		atomic_inc(&sk->sk_drops);
E
Eric Dumazet 已提交
1092 1093 1094 1095 1096 1097 1098
		__skb_unlink(skb, rcvq);
		__skb_queue_tail(&list_kill, skb);
	}
	res = skb ? skb->len : 0;
	spin_unlock_bh(&rcvq->lock);

	if (!skb_queue_empty(&list_kill)) {
1099 1100
		bool slow = lock_sock_fast(sk);

E
Eric Dumazet 已提交
1101 1102
		__skb_queue_purge(&list_kill);
		sk_mem_reclaim_partial(sk);
1103
		unlock_sock_fast(sk, slow);
E
Eric Dumazet 已提交
1104 1105 1106 1107
	}
	return res;
}

L
Linus Torvalds 已提交
1108 1109 1110
/*
 *	IOCTL requests applicable to the UDP protocol
 */
1111

L
Linus Torvalds 已提交
1112 1113
int udp_ioctl(struct sock *sk, int cmd, unsigned long arg)
{
1114 1115
	switch (cmd) {
	case SIOCOUTQ:
L
Linus Torvalds 已提交
1116
	{
1117 1118
		int amount = sk_wmem_alloc_get(sk);

1119 1120
		return put_user(amount, (int __user *)arg);
	}
L
Linus Torvalds 已提交
1121

1122 1123
	case SIOCINQ:
	{
E
Eric Dumazet 已提交
1124
		unsigned int amount = first_packet_length(sk);
1125

E
Eric Dumazet 已提交
1126
		if (amount)
1127 1128 1129 1130 1131
			/*
			 * We will only return the amount
			 * of this packet since that is all
			 * that will be read.
			 */
E
Eric Dumazet 已提交
1132 1133
			amount -= sizeof(struct udphdr);

1134 1135
		return put_user(amount, (int __user *)arg);
	}
L
Linus Torvalds 已提交
1136

1137 1138
	default:
		return -ENOIOCTLCMD;
L
Linus Torvalds 已提交
1139
	}
1140 1141

	return 0;
L
Linus Torvalds 已提交
1142
}
E
Eric Dumazet 已提交
1143
EXPORT_SYMBOL(udp_ioctl);
L
Linus Torvalds 已提交
1144

1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155
/*
 * 	This should be easy, if there is something there we
 * 	return it, otherwise we block.
 */

int udp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
		size_t len, int noblock, int flags, int *addr_len)
{
	struct inet_sock *inet = inet_sk(sk);
	struct sockaddr_in *sin = (struct sockaddr_in *)msg->msg_name;
	struct sk_buff *skb;
G
Gerrit Renker 已提交
1156
	unsigned int ulen;
1157 1158 1159
	int peeked;
	int err;
	int is_udplite = IS_UDPLITE(sk);
1160
	bool slow;
1161 1162 1163 1164 1165

	/*
	 *	Check any passed addresses
	 */
	if (addr_len)
E
Eric Dumazet 已提交
1166
		*addr_len = sizeof(*sin);
1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177

	if (flags & MSG_ERRQUEUE)
		return ip_recv_error(sk, msg, len);

try_again:
	skb = __skb_recv_datagram(sk, flags | (noblock ? MSG_DONTWAIT : 0),
				  &peeked, &err);
	if (!skb)
		goto out;

	ulen = skb->len - sizeof(struct udphdr);
G
Gerrit Renker 已提交
1178 1179 1180
	if (len > ulen)
		len = ulen;
	else if (len < ulen)
1181 1182 1183 1184 1185 1186 1187 1188
		msg->msg_flags |= MSG_TRUNC;

	/*
	 * If checksum is needed at all, try to do it while copying the
	 * data.  If the data is truncated, or if we only want a partial
	 * coverage checksum (UDP-Lite), do it before the copy.
	 */

G
Gerrit Renker 已提交
1189
	if (len < ulen || UDP_SKB_CB(skb)->partial_cov) {
1190 1191 1192 1193 1194 1195
		if (udp_lib_checksum_complete(skb))
			goto csum_copy_err;
	}

	if (skb_csum_unnecessary(skb))
		err = skb_copy_datagram_iovec(skb, sizeof(struct udphdr),
G
Gerrit Renker 已提交
1196
					      msg->msg_iov, len);
1197
	else {
E
Eric Dumazet 已提交
1198 1199 1200
		err = skb_copy_and_csum_datagram_iovec(skb,
						       sizeof(struct udphdr),
						       msg->msg_iov);
1201 1202 1203 1204 1205 1206 1207 1208 1209

		if (err == -EINVAL)
			goto csum_copy_err;
	}

	if (err)
		goto out_free;

	if (!peeked)
1210 1211
		UDP_INC_STATS_USER(sock_net(sk),
				UDP_MIB_INDATAGRAMS, is_udplite);
1212

1213
	sock_recv_ts_and_drops(msg, sk, skb);
1214 1215

	/* Copy the address. */
E
Eric Dumazet 已提交
1216
	if (sin) {
1217 1218 1219 1220 1221 1222 1223 1224
		sin->sin_family = AF_INET;
		sin->sin_port = udp_hdr(skb)->source;
		sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
		memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
	}
	if (inet->cmsg_flags)
		ip_cmsg_recv(msg, skb);

G
Gerrit Renker 已提交
1225
	err = len;
1226 1227 1228 1229
	if (flags & MSG_TRUNC)
		err = ulen;

out_free:
1230
	skb_free_datagram_locked(sk, skb);
1231 1232 1233 1234
out:
	return err;

csum_copy_err:
1235
	slow = lock_sock_fast(sk);
1236
	if (!skb_kill_datagram(sk, skb, flags))
1237
		UDP_INC_STATS_USER(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
1238
	unlock_sock_fast(sk, slow);
1239 1240 1241 1242 1243 1244 1245

	if (noblock)
		return -EAGAIN;
	goto try_again;
}


L
Linus Torvalds 已提交
1246 1247 1248 1249 1250 1251
int udp_disconnect(struct sock *sk, int flags)
{
	struct inet_sock *inet = inet_sk(sk);
	/*
	 *	1003.1g - break association.
	 */
1252

L
Linus Torvalds 已提交
1253
	sk->sk_state = TCP_CLOSE;
E
Eric Dumazet 已提交
1254 1255
	inet->inet_daddr = 0;
	inet->inet_dport = 0;
1256
	sock_rps_save_rxhash(sk, 0);
L
Linus Torvalds 已提交
1257 1258 1259 1260 1261 1262
	sk->sk_bound_dev_if = 0;
	if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
		inet_reset_saddr(sk);

	if (!(sk->sk_userlocks & SOCK_BINDPORT_LOCK)) {
		sk->sk_prot->unhash(sk);
E
Eric Dumazet 已提交
1263
		inet->inet_sport = 0;
L
Linus Torvalds 已提交
1264 1265 1266 1267
	}
	sk_dst_reset(sk);
	return 0;
}
E
Eric Dumazet 已提交
1268
EXPORT_SYMBOL(udp_disconnect);
L
Linus Torvalds 已提交
1269

1270 1271
void udp_lib_unhash(struct sock *sk)
{
1272 1273
	if (sk_hashed(sk)) {
		struct udp_table *udptable = sk->sk_prot->h.udp_table;
1274 1275 1276 1277 1278
		struct udp_hslot *hslot, *hslot2;

		hslot  = udp_hashslot(udptable, sock_net(sk),
				      udp_sk(sk)->udp_port_hash);
		hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash);
1279

1280 1281
		spin_lock_bh(&hslot->lock);
		if (sk_nulls_del_node_init_rcu(sk)) {
E
Eric Dumazet 已提交
1282
			hslot->count--;
E
Eric Dumazet 已提交
1283
			inet_sk(sk)->inet_num = 0;
1284
			sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
1285 1286 1287 1288 1289

			spin_lock(&hslot2->lock);
			hlist_nulls_del_init_rcu(&udp_sk(sk)->udp_portaddr_node);
			hslot2->count--;
			spin_unlock(&hslot2->lock);
1290 1291
		}
		spin_unlock_bh(&hslot->lock);
1292 1293 1294 1295
	}
}
EXPORT_SYMBOL(udp_lib_unhash);

E
Eric Dumazet 已提交
1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338
/*
 * inet_rcv_saddr was changed, we must rehash secondary hash
 */
void udp_lib_rehash(struct sock *sk, u16 newhash)
{
	if (sk_hashed(sk)) {
		struct udp_table *udptable = sk->sk_prot->h.udp_table;
		struct udp_hslot *hslot, *hslot2, *nhslot2;

		hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash);
		nhslot2 = udp_hashslot2(udptable, newhash);
		udp_sk(sk)->udp_portaddr_hash = newhash;
		if (hslot2 != nhslot2) {
			hslot = udp_hashslot(udptable, sock_net(sk),
					     udp_sk(sk)->udp_port_hash);
			/* we must lock primary chain too */
			spin_lock_bh(&hslot->lock);

			spin_lock(&hslot2->lock);
			hlist_nulls_del_init_rcu(&udp_sk(sk)->udp_portaddr_node);
			hslot2->count--;
			spin_unlock(&hslot2->lock);

			spin_lock(&nhslot2->lock);
			hlist_nulls_add_head_rcu(&udp_sk(sk)->udp_portaddr_node,
						 &nhslot2->head);
			nhslot2->count++;
			spin_unlock(&nhslot2->lock);

			spin_unlock_bh(&hslot->lock);
		}
	}
}
EXPORT_SYMBOL(udp_lib_rehash);

static void udp_v4_rehash(struct sock *sk)
{
	u16 new_hash = udp4_portaddr_hash(sock_net(sk),
					  inet_sk(sk)->inet_rcv_saddr,
					  inet_sk(sk)->inet_num);
	udp_lib_rehash(sk, new_hash);
}

H
Herbert Xu 已提交
1339 1340
static int __udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
{
T
Tom Herbert 已提交
1341
	int rc;
E
Eric Dumazet 已提交
1342

T
Tom Herbert 已提交
1343
	if (inet_sk(sk)->inet_daddr)
1344
		sock_rps_save_rxhash(sk, skb->rxhash);
T
Tom Herbert 已提交
1345

E
Eric Dumazet 已提交
1346
	rc = ip_queue_rcv_skb(sk, skb);
E
Eric Dumazet 已提交
1347 1348
	if (rc < 0) {
		int is_udplite = IS_UDPLITE(sk);
H
Herbert Xu 已提交
1349 1350

		/* Note that an ENOMEM error is charged twice */
E
Eric Dumazet 已提交
1351
		if (rc == -ENOMEM)
H
Herbert Xu 已提交
1352 1353
			UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_RCVBUFERRORS,
					 is_udplite);
E
Eric Dumazet 已提交
1354 1355 1356
		UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
		kfree_skb(skb);
		return -1;
H
Herbert Xu 已提交
1357 1358 1359 1360 1361 1362
	}

	return 0;

}

1363 1364 1365 1366 1367 1368 1369 1370
/* returns:
 *  -1: error
 *   0: success
 *  >0: "udp encap" protocol resubmission
 *
 * Note that in the success and error cases, the skb is assumed to
 * have either been requeued or freed.
 */
E
Eric Dumazet 已提交
1371
int udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402
{
	struct udp_sock *up = udp_sk(sk);
	int rc;
	int is_udplite = IS_UDPLITE(sk);

	/*
	 *	Charge it to the socket, dropping if the queue is full.
	 */
	if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
		goto drop;
	nf_reset(skb);

	if (up->encap_type) {
		/*
		 * This is an encapsulation socket so pass the skb to
		 * the socket's udp_encap_rcv() hook. Otherwise, just
		 * fall through and pass this up the UDP socket.
		 * up->encap_rcv() returns the following value:
		 * =0 if skb was successfully passed to the encap
		 *    handler or was discarded by it.
		 * >0 if skb should be passed on to UDP.
		 * <0 if skb should be resubmitted as proto -N
		 */

		/* if we're overly short, let UDP handle it */
		if (skb->len > sizeof(struct udphdr) &&
		    up->encap_rcv != NULL) {
			int ret;

			ret = (*up->encap_rcv)(sk, skb);
			if (ret <= 0) {
1403 1404
				UDP_INC_STATS_BH(sock_net(sk),
						 UDP_MIB_INDATAGRAMS,
1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448
						 is_udplite);
				return -ret;
			}
		}

		/* FALLTHROUGH -- it's a UDP Packet */
	}

	/*
	 * 	UDP-Lite specific tests, ignored on UDP sockets
	 */
	if ((is_udplite & UDPLITE_RECV_CC)  &&  UDP_SKB_CB(skb)->partial_cov) {

		/*
		 * MIB statistics other than incrementing the error count are
		 * disabled for the following two types of errors: these depend
		 * on the application settings, not on the functioning of the
		 * protocol stack as such.
		 *
		 * RFC 3828 here recommends (sec 3.3): "There should also be a
		 * way ... to ... at least let the receiving application block
		 * delivery of packets with coverage values less than a value
		 * provided by the application."
		 */
		if (up->pcrlen == 0) {          /* full coverage was set  */
			LIMIT_NETDEBUG(KERN_WARNING "UDPLITE: partial coverage "
				"%d while full coverage %d requested\n",
				UDP_SKB_CB(skb)->cscov, skb->len);
			goto drop;
		}
		/* The next case involves violating the min. coverage requested
		 * by the receiver. This is subtle: if receiver wants x and x is
		 * greater than the buffersize/MTU then receiver will complain
		 * that it wants x while sender emits packets of smaller size y.
		 * Therefore the above ...()->partial_cov statement is essential.
		 */
		if (UDP_SKB_CB(skb)->cscov  <  up->pcrlen) {
			LIMIT_NETDEBUG(KERN_WARNING
				"UDPLITE: coverage %d too small, need min %d\n",
				UDP_SKB_CB(skb)->cscov, up->pcrlen);
			goto drop;
		}
	}

1449
	if (rcu_dereference_raw(sk->sk_filter)) {
1450 1451 1452 1453
		if (udp_lib_checksum_complete(skb))
			goto drop;
	}

1454 1455 1456 1457

	if (sk_rcvqueues_full(sk, skb))
		goto drop;

H
Herbert Xu 已提交
1458
	rc = 0;
1459

H
Herbert Xu 已提交
1460 1461 1462
	bh_lock_sock(sk);
	if (!sock_owned_by_user(sk))
		rc = __udp_queue_rcv_skb(sk, skb);
Z
Zhu Yi 已提交
1463
	else if (sk_add_backlog(sk, skb)) {
Z
Zhu Yi 已提交
1464 1465 1466
		bh_unlock_sock(sk);
		goto drop;
	}
H
Herbert Xu 已提交
1467 1468 1469
	bh_unlock_sock(sk);

	return rc;
1470 1471

drop:
1472
	UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
E
Eric Dumazet 已提交
1473
	atomic_inc(&sk->sk_drops);
1474 1475 1476 1477
	kfree_skb(skb);
	return -1;
}

1478 1479 1480 1481 1482 1483

static void flush_stack(struct sock **stack, unsigned int count,
			struct sk_buff *skb, unsigned int final)
{
	unsigned int i;
	struct sk_buff *skb1 = NULL;
1484
	struct sock *sk;
1485 1486

	for (i = 0; i < count; i++) {
1487
		sk = stack[i];
1488 1489 1490
		if (likely(skb1 == NULL))
			skb1 = (i == final) ? skb : skb_clone(skb, GFP_ATOMIC);

1491 1492 1493 1494 1495 1496 1497 1498 1499
		if (!skb1) {
			atomic_inc(&sk->sk_drops);
			UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_RCVBUFERRORS,
					 IS_UDPLITE(sk));
			UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS,
					 IS_UDPLITE(sk));
		}

		if (skb1 && udp_queue_rcv_skb(sk, skb1) <= 0)
1500 1501 1502 1503 1504 1505
			skb1 = NULL;
	}
	if (unlikely(skb1))
		kfree_skb(skb1);
}

1506 1507 1508
/*
 *	Multicasts and broadcasts go to each listener.
 *
1509
 *	Note: called only from the BH handler context.
1510
 */
1511
static int __udp4_lib_mcast_deliver(struct net *net, struct sk_buff *skb,
1512 1513
				    struct udphdr  *uh,
				    __be32 saddr, __be32 daddr,
1514
				    struct udp_table *udptable)
1515
{
1516
	struct sock *sk, *stack[256 / sizeof(struct sock *)];
1517
	struct udp_hslot *hslot = udp_hashslot(udptable, net, ntohs(uh->dest));
1518
	int dif;
1519
	unsigned int i, count = 0;
1520

1521
	spin_lock(&hslot->lock);
1522
	sk = sk_nulls_head(&hslot->head);
1523
	dif = skb->dev->ifindex;
1524
	sk = udp_v4_mcast_next(net, sk, uh->dest, daddr, uh->source, saddr, dif);
1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541
	while (sk) {
		stack[count++] = sk;
		sk = udp_v4_mcast_next(net, sk_nulls_next(sk), uh->dest,
				       daddr, uh->source, saddr, dif);
		if (unlikely(count == ARRAY_SIZE(stack))) {
			if (!sk)
				break;
			flush_stack(stack, count, skb, ~0);
			count = 0;
		}
	}
	/*
	 * before releasing chain lock, we must take a reference on sockets
	 */
	for (i = 0; i < count; i++)
		sock_hold(stack[i]);

1542
	spin_unlock(&hslot->lock);
1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554

	/*
	 * do the slow work with no lock held
	 */
	if (count) {
		flush_stack(stack, count, skb, count - 1);

		for (i = 0; i < count; i++)
			sock_put(stack[i]);
	} else {
		kfree_skb(skb);
	}
1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581
	return 0;
}

/* Initialize UDP checksum. If exited with zero value (success),
 * CHECKSUM_UNNECESSARY means, that no more checks are required.
 * Otherwise, csum completion requires chacksumming packet body,
 * including udp header and folding it to skb->csum.
 */
static inline int udp4_csum_init(struct sk_buff *skb, struct udphdr *uh,
				 int proto)
{
	const struct iphdr *iph;
	int err;

	UDP_SKB_CB(skb)->partial_cov = 0;
	UDP_SKB_CB(skb)->cscov = skb->len;

	if (proto == IPPROTO_UDPLITE) {
		err = udplite_checksum_init(skb, uh);
		if (err)
			return err;
	}

	iph = ip_hdr(skb);
	if (uh->check == 0) {
		skb->ip_summed = CHECKSUM_UNNECESSARY;
	} else if (skb->ip_summed == CHECKSUM_COMPLETE) {
E
Eric Dumazet 已提交
1582
		if (!csum_tcpudp_magic(iph->saddr, iph->daddr, skb->len,
1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599
				      proto, skb->csum))
			skb->ip_summed = CHECKSUM_UNNECESSARY;
	}
	if (!skb_csum_unnecessary(skb))
		skb->csum = csum_tcpudp_nofold(iph->saddr, iph->daddr,
					       skb->len, proto, 0);
	/* Probably, we should checksum udp header (it should be in cache
	 * in any case) and data in tiny packets (< rx copybreak).
	 */

	return 0;
}

/*
 *	All we need to do is get the socket, and then do a checksum.
 */

1600
int __udp4_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
1601 1602 1603
		   int proto)
{
	struct sock *sk;
1604
	struct udphdr *uh;
1605
	unsigned short ulen;
E
Eric Dumazet 已提交
1606
	struct rtable *rt = skb_rtable(skb);
1607
	__be32 saddr, daddr;
1608
	struct net *net = dev_net(skb->dev);
1609 1610 1611 1612 1613 1614 1615

	/*
	 *  Validate the packet.
	 */
	if (!pskb_may_pull(skb, sizeof(struct udphdr)))
		goto drop;		/* No space for header. */

1616
	uh   = udp_hdr(skb);
1617
	ulen = ntohs(uh->len);
1618 1619 1620
	saddr = ip_hdr(skb)->saddr;
	daddr = ip_hdr(skb)->daddr;

1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633 1634
	if (ulen > skb->len)
		goto short_packet;

	if (proto == IPPROTO_UDP) {
		/* UDP validates ulen. */
		if (ulen < sizeof(*uh) || pskb_trim_rcsum(skb, ulen))
			goto short_packet;
		uh = udp_hdr(skb);
	}

	if (udp4_csum_init(skb, uh, proto))
		goto csum_error;

	if (rt->rt_flags & (RTCF_BROADCAST|RTCF_MULTICAST))
1635 1636
		return __udp4_lib_mcast_deliver(net, skb, uh,
				saddr, daddr, udptable);
1637

1638
	sk = __udp4_lib_lookup_skb(skb, uh->source, uh->dest, udptable);
1639 1640

	if (sk != NULL) {
H
Herbert Xu 已提交
1641
		int ret = udp_queue_rcv_skb(sk, skb);
1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659
		sock_put(sk);

		/* a return value > 0 means to resubmit the input, but
		 * it wants the return to be -protocol, or 0
		 */
		if (ret > 0)
			return -ret;
		return 0;
	}

	if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
		goto drop;
	nf_reset(skb);

	/* No socket. Drop packet silently, if checksum is wrong */
	if (udp_lib_checksum_complete(skb))
		goto csum_error;

1660
	UDP_INC_STATS_BH(net, UDP_MIB_NOPORTS, proto == IPPROTO_UDPLITE);
1661 1662 1663 1664 1665 1666 1667 1668 1669 1670
	icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);

	/*
	 * Hmm.  We got an UDP packet to a port to which we
	 * don't wanna listen.  Ignore it.
	 */
	kfree_skb(skb);
	return 0;

short_packet:
1671
	LIMIT_NETDEBUG(KERN_DEBUG "UDP%s: short packet: From %pI4:%u %d/%d to %pI4:%u\n",
1672
		       proto == IPPROTO_UDPLITE ? "-Lite" : "",
1673
		       &saddr,
1674 1675 1676
		       ntohs(uh->source),
		       ulen,
		       skb->len,
1677
		       &daddr,
1678 1679 1680 1681 1682 1683 1684 1685
		       ntohs(uh->dest));
	goto drop;

csum_error:
	/*
	 * RFC1122: OK.  Discards the bad packet silently (as far as
	 * the network is concerned, anyway) as per 4.1.3.4 (MUST).
	 */
1686
	LIMIT_NETDEBUG(KERN_DEBUG "UDP%s: bad checksum. From %pI4:%u to %pI4:%u ulen %d\n",
1687
		       proto == IPPROTO_UDPLITE ? "-Lite" : "",
1688
		       &saddr,
1689
		       ntohs(uh->source),
1690
		       &daddr,
1691 1692 1693
		       ntohs(uh->dest),
		       ulen);
drop:
1694
	UDP_INC_STATS_BH(net, UDP_MIB_INERRORS, proto == IPPROTO_UDPLITE);
1695 1696 1697 1698 1699 1700
	kfree_skb(skb);
	return 0;
}

int udp_rcv(struct sk_buff *skb)
{
1701
	return __udp4_lib_rcv(skb, &udp_table, IPPROTO_UDP);
1702 1703
}

1704
void udp_destroy_sock(struct sock *sk)
1705
{
1706
	bool slow = lock_sock_fast(sk);
1707
	udp_flush_pending_frames(sk);
1708
	unlock_sock_fast(sk, slow);
1709 1710
}

L
Linus Torvalds 已提交
1711 1712 1713
/*
 *	Socket option code for UDP
 */
1714
int udp_lib_setsockopt(struct sock *sk, int level, int optname,
1715
		       char __user *optval, unsigned int optlen,
1716
		       int (*push_pending_frames)(struct sock *))
L
Linus Torvalds 已提交
1717 1718 1719 1720
{
	struct udp_sock *up = udp_sk(sk);
	int val;
	int err = 0;
W
Wang Chen 已提交
1721
	int is_udplite = IS_UDPLITE(sk);
L
Linus Torvalds 已提交
1722

E
Eric Dumazet 已提交
1723
	if (optlen < sizeof(int))
L
Linus Torvalds 已提交
1724 1725 1726 1727 1728
		return -EINVAL;

	if (get_user(val, (int __user *)optval))
		return -EFAULT;

1729
	switch (optname) {
L
Linus Torvalds 已提交
1730 1731 1732 1733 1734 1735
	case UDP_CORK:
		if (val != 0) {
			up->corkflag = 1;
		} else {
			up->corkflag = 0;
			lock_sock(sk);
1736
			(*push_pending_frames)(sk);
L
Linus Torvalds 已提交
1737 1738 1739
			release_sock(sk);
		}
		break;
1740

L
Linus Torvalds 已提交
1741 1742 1743 1744 1745
	case UDP_ENCAP:
		switch (val) {
		case 0:
		case UDP_ENCAP_ESPINUDP:
		case UDP_ENCAP_ESPINUDP_NON_IKE:
1746 1747
			up->encap_rcv = xfrm4_udp_encap_rcv;
			/* FALLTHROUGH */
1748
		case UDP_ENCAP_L2TPINUDP:
L
Linus Torvalds 已提交
1749 1750 1751 1752 1753 1754 1755 1756
			up->encap_type = val;
			break;
		default:
			err = -ENOPROTOOPT;
			break;
		}
		break;

1757 1758 1759 1760 1761 1762
	/*
	 * 	UDP-Lite's partial checksum coverage (RFC 3828).
	 */
	/* The sender sets actual checksum coverage length via this option.
	 * The case coverage > packet length is handled by send module. */
	case UDPLITE_SEND_CSCOV:
W
Wang Chen 已提交
1763
		if (!is_udplite)         /* Disable the option on UDP sockets */
1764 1765 1766
			return -ENOPROTOOPT;
		if (val != 0 && val < 8) /* Illegal coverage: use default (8) */
			val = 8;
1767 1768
		else if (val > USHRT_MAX)
			val = USHRT_MAX;
1769 1770 1771 1772
		up->pcslen = val;
		up->pcflag |= UDPLITE_SEND_CC;
		break;

1773 1774
	/* The receiver specifies a minimum checksum coverage value. To make
	 * sense, this should be set to at least 8 (as done below). If zero is
1775 1776
	 * used, this again means full checksum coverage.                     */
	case UDPLITE_RECV_CSCOV:
W
Wang Chen 已提交
1777
		if (!is_udplite)         /* Disable the option on UDP sockets */
1778 1779 1780
			return -ENOPROTOOPT;
		if (val != 0 && val < 8) /* Avoid silly minimal values.       */
			val = 8;
1781 1782
		else if (val > USHRT_MAX)
			val = USHRT_MAX;
1783 1784 1785 1786
		up->pcrlen = val;
		up->pcflag |= UDPLITE_RECV_CC;
		break;

L
Linus Torvalds 已提交
1787 1788 1789
	default:
		err = -ENOPROTOOPT;
		break;
1790
	}
L
Linus Torvalds 已提交
1791 1792 1793

	return err;
}
E
Eric Dumazet 已提交
1794
EXPORT_SYMBOL(udp_lib_setsockopt);
L
Linus Torvalds 已提交
1795

1796
int udp_setsockopt(struct sock *sk, int level, int optname,
1797
		   char __user *optval, unsigned int optlen)
1798 1799 1800 1801 1802 1803 1804 1805 1806
{
	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
		return udp_lib_setsockopt(sk, level, optname, optval, optlen,
					  udp_push_pending_frames);
	return ip_setsockopt(sk, level, optname, optval, optlen);
}

#ifdef CONFIG_COMPAT
int compat_udp_setsockopt(struct sock *sk, int level, int optname,
1807
			  char __user *optval, unsigned int optlen)
1808 1809 1810 1811 1812 1813 1814 1815
{
	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
		return udp_lib_setsockopt(sk, level, optname, optval, optlen,
					  udp_push_pending_frames);
	return compat_ip_setsockopt(sk, level, optname, optval, optlen);
}
#endif

1816 1817
int udp_lib_getsockopt(struct sock *sk, int level, int optname,
		       char __user *optval, int __user *optlen)
L
Linus Torvalds 已提交
1818 1819 1820 1821
{
	struct udp_sock *up = udp_sk(sk);
	int val, len;

E
Eric Dumazet 已提交
1822
	if (get_user(len, optlen))
L
Linus Torvalds 已提交
1823 1824 1825
		return -EFAULT;

	len = min_t(unsigned int, len, sizeof(int));
1826

1827
	if (len < 0)
L
Linus Torvalds 已提交
1828 1829
		return -EINVAL;

1830
	switch (optname) {
L
Linus Torvalds 已提交
1831 1832 1833 1834 1835 1836 1837 1838
	case UDP_CORK:
		val = up->corkflag;
		break;

	case UDP_ENCAP:
		val = up->encap_type;
		break;

1839 1840 1841 1842 1843 1844 1845 1846 1847 1848
	/* The following two cannot be changed on UDP sockets, the return is
	 * always 0 (which corresponds to the full checksum coverage of UDP). */
	case UDPLITE_SEND_CSCOV:
		val = up->pcslen;
		break;

	case UDPLITE_RECV_CSCOV:
		val = up->pcrlen;
		break;

L
Linus Torvalds 已提交
1849 1850
	default:
		return -ENOPROTOOPT;
1851
	}
L
Linus Torvalds 已提交
1852

1853
	if (put_user(len, optlen))
1854
		return -EFAULT;
E
Eric Dumazet 已提交
1855
	if (copy_to_user(optval, &val, len))
L
Linus Torvalds 已提交
1856
		return -EFAULT;
1857
	return 0;
L
Linus Torvalds 已提交
1858
}
E
Eric Dumazet 已提交
1859
EXPORT_SYMBOL(udp_lib_getsockopt);
L
Linus Torvalds 已提交
1860

1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877
int udp_getsockopt(struct sock *sk, int level, int optname,
		   char __user *optval, int __user *optlen)
{
	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
		return udp_lib_getsockopt(sk, level, optname, optval, optlen);
	return ip_getsockopt(sk, level, optname, optval, optlen);
}

#ifdef CONFIG_COMPAT
int compat_udp_getsockopt(struct sock *sk, int level, int optname,
				 char __user *optval, int __user *optlen)
{
	if (level == SOL_UDP  ||  level == SOL_UDPLITE)
		return udp_lib_getsockopt(sk, level, optname, optval, optlen);
	return compat_ip_getsockopt(sk, level, optname, optval, optlen);
}
#endif
L
Linus Torvalds 已提交
1878 1879 1880 1881 1882 1883
/**
 * 	udp_poll - wait for a UDP event.
 *	@file - file struct
 *	@sock - socket
 *	@wait - poll table
 *
1884
 *	This is same as datagram poll, except for the special case of
L
Linus Torvalds 已提交
1885 1886 1887 1888 1889 1890 1891 1892 1893 1894
 *	blocking sockets. If application is using a blocking fd
 *	and a packet with checksum error is in the queue;
 *	then it could get return from select indicating data available
 *	but then block when reading it. Add special case code
 *	to work around these arguably broken applications.
 */
unsigned int udp_poll(struct file *file, struct socket *sock, poll_table *wait)
{
	unsigned int mask = datagram_poll(file, sock, wait);
	struct sock *sk = sock->sk;
1895

L
Linus Torvalds 已提交
1896
	/* Check for false positives due to checksum errors */
E
Eric Dumazet 已提交
1897 1898 1899
	if ((mask & POLLRDNORM) && !(file->f_flags & O_NONBLOCK) &&
	    !(sk->sk_shutdown & RCV_SHUTDOWN) && !first_packet_length(sk))
		mask &= ~(POLLIN | POLLRDNORM);
L
Linus Torvalds 已提交
1900 1901

	return mask;
1902

L
Linus Torvalds 已提交
1903
}
E
Eric Dumazet 已提交
1904
EXPORT_SYMBOL(udp_poll);
L
Linus Torvalds 已提交
1905

1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918
struct proto udp_prot = {
	.name		   = "UDP",
	.owner		   = THIS_MODULE,
	.close		   = udp_lib_close,
	.connect	   = ip4_datagram_connect,
	.disconnect	   = udp_disconnect,
	.ioctl		   = udp_ioctl,
	.destroy	   = udp_destroy_sock,
	.setsockopt	   = udp_setsockopt,
	.getsockopt	   = udp_getsockopt,
	.sendmsg	   = udp_sendmsg,
	.recvmsg	   = udp_recvmsg,
	.sendpage	   = udp_sendpage,
H
Herbert Xu 已提交
1919
	.backlog_rcv	   = __udp_queue_rcv_skb,
1920 1921
	.hash		   = udp_lib_hash,
	.unhash		   = udp_lib_unhash,
E
Eric Dumazet 已提交
1922
	.rehash		   = udp_v4_rehash,
1923 1924 1925 1926 1927 1928
	.get_port	   = udp_v4_get_port,
	.memory_allocated  = &udp_memory_allocated,
	.sysctl_mem	   = sysctl_udp_mem,
	.sysctl_wmem	   = &sysctl_udp_wmem_min,
	.sysctl_rmem	   = &sysctl_udp_rmem_min,
	.obj_size	   = sizeof(struct udp_sock),
1929
	.slab_flags	   = SLAB_DESTROY_BY_RCU,
1930
	.h.udp_table	   = &udp_table,
1931 1932 1933 1934
#ifdef CONFIG_COMPAT
	.compat_setsockopt = compat_udp_setsockopt,
	.compat_getsockopt = compat_udp_getsockopt,
#endif
1935
	.clear_sk	   = sk_prot_clear_portaddr_nulls,
1936
};
E
Eric Dumazet 已提交
1937
EXPORT_SYMBOL(udp_prot);
L
Linus Torvalds 已提交
1938 1939 1940 1941

/* ------------------------------------------------------------------------ */
#ifdef CONFIG_PROC_FS

1942
static struct sock *udp_get_first(struct seq_file *seq, int start)
L
Linus Torvalds 已提交
1943 1944 1945
{
	struct sock *sk;
	struct udp_iter_state *state = seq->private;
1946
	struct net *net = seq_file_net(seq);
L
Linus Torvalds 已提交
1947

1948 1949
	for (state->bucket = start; state->bucket <= state->udp_table->mask;
	     ++state->bucket) {
1950
		struct hlist_nulls_node *node;
1951
		struct udp_hslot *hslot = &state->udp_table->hash[state->bucket];
1952 1953 1954 1955

		if (hlist_nulls_empty(&hslot->head))
			continue;

1956
		spin_lock_bh(&hslot->lock);
1957
		sk_nulls_for_each(sk, node, &hslot->head) {
1958
			if (!net_eq(sock_net(sk), net))
1959
				continue;
L
Linus Torvalds 已提交
1960 1961 1962
			if (sk->sk_family == state->family)
				goto found;
		}
1963
		spin_unlock_bh(&hslot->lock);
L
Linus Torvalds 已提交
1964 1965 1966 1967 1968 1969 1970 1971 1972
	}
	sk = NULL;
found:
	return sk;
}

static struct sock *udp_get_next(struct seq_file *seq, struct sock *sk)
{
	struct udp_iter_state *state = seq->private;
1973
	struct net *net = seq_file_net(seq);
L
Linus Torvalds 已提交
1974 1975

	do {
1976
		sk = sk_nulls_next(sk);
1977
	} while (sk && (!net_eq(sock_net(sk), net) || sk->sk_family != state->family));
L
Linus Torvalds 已提交
1978

1979
	if (!sk) {
1980
		if (state->bucket <= state->udp_table->mask)
1981
			spin_unlock_bh(&state->udp_table->hash[state->bucket].lock);
1982
		return udp_get_first(seq, state->bucket + 1);
L
Linus Torvalds 已提交
1983 1984 1985 1986 1987 1988
	}
	return sk;
}

static struct sock *udp_get_idx(struct seq_file *seq, loff_t pos)
{
1989
	struct sock *sk = udp_get_first(seq, 0);
L
Linus Torvalds 已提交
1990 1991

	if (sk)
1992
		while (pos && (sk = udp_get_next(seq, sk)) != NULL)
L
Linus Torvalds 已提交
1993 1994 1995 1996 1997 1998
			--pos;
	return pos ? NULL : sk;
}

static void *udp_seq_start(struct seq_file *seq, loff_t *pos)
{
1999
	struct udp_iter_state *state = seq->private;
2000
	state->bucket = MAX_UDP_PORTS;
2001

2002
	return *pos ? udp_get_idx(seq, *pos-1) : SEQ_START_TOKEN;
L
Linus Torvalds 已提交
2003 2004 2005 2006 2007 2008
}

static void *udp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
	struct sock *sk;

2009
	if (v == SEQ_START_TOKEN)
L
Linus Torvalds 已提交
2010 2011 2012 2013 2014 2015 2016 2017 2018 2019
		sk = udp_get_idx(seq, 0);
	else
		sk = udp_get_next(seq, v);

	++*pos;
	return sk;
}

static void udp_seq_stop(struct seq_file *seq, void *v)
{
2020 2021
	struct udp_iter_state *state = seq->private;

2022
	if (state->bucket <= state->udp_table->mask)
2023
		spin_unlock_bh(&state->udp_table->hash[state->bucket].lock);
L
Linus Torvalds 已提交
2024 2025 2026 2027 2028
}

static int udp_seq_open(struct inode *inode, struct file *file)
{
	struct udp_seq_afinfo *afinfo = PDE(inode)->data;
2029 2030
	struct udp_iter_state *s;
	int err;
2031

2032 2033 2034 2035
	err = seq_open_net(inode, file, &afinfo->seq_ops,
			   sizeof(struct udp_iter_state));
	if (err < 0)
		return err;
2036

2037
	s = ((struct seq_file *)file->private_data)->private;
L
Linus Torvalds 已提交
2038
	s->family		= afinfo->family;
2039
	s->udp_table		= afinfo->udp_table;
2040
	return err;
2041 2042
}

L
Linus Torvalds 已提交
2043
/* ------------------------------------------------------------------------ */
2044
int udp_proc_register(struct net *net, struct udp_seq_afinfo *afinfo)
L
Linus Torvalds 已提交
2045 2046 2047 2048
{
	struct proc_dir_entry *p;
	int rc = 0;

2049 2050 2051 2052
	afinfo->seq_fops.open		= udp_seq_open;
	afinfo->seq_fops.read		= seq_read;
	afinfo->seq_fops.llseek		= seq_lseek;
	afinfo->seq_fops.release	= seq_release_net;
L
Linus Torvalds 已提交
2053

2054 2055 2056 2057
	afinfo->seq_ops.start		= udp_seq_start;
	afinfo->seq_ops.next		= udp_seq_next;
	afinfo->seq_ops.stop		= udp_seq_stop;

2058 2059 2060
	p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
			     &afinfo->seq_fops, afinfo);
	if (!p)
L
Linus Torvalds 已提交
2061 2062 2063
		rc = -ENOMEM;
	return rc;
}
E
Eric Dumazet 已提交
2064
EXPORT_SYMBOL(udp_proc_register);
L
Linus Torvalds 已提交
2065

2066
void udp_proc_unregister(struct net *net, struct udp_seq_afinfo *afinfo)
L
Linus Torvalds 已提交
2067
{
2068
	proc_net_remove(net, afinfo->name);
L
Linus Torvalds 已提交
2069
}
E
Eric Dumazet 已提交
2070
EXPORT_SYMBOL(udp_proc_unregister);
2071 2072

/* ------------------------------------------------------------------------ */
2073 2074
static void udp4_format_sock(struct sock *sp, struct seq_file *f,
		int bucket, int *len)
2075 2076
{
	struct inet_sock *inet = inet_sk(sp);
E
Eric Dumazet 已提交
2077 2078 2079 2080
	__be32 dest = inet->inet_daddr;
	__be32 src  = inet->inet_rcv_saddr;
	__u16 destp	  = ntohs(inet->inet_dport);
	__u16 srcp	  = ntohs(inet->inet_sport);
2081

2082
	seq_printf(f, "%5d: %08X:%04X %08X:%04X"
E
Eric Dumazet 已提交
2083
		" %02X %08X:%08X %02X:%08lX %08X %5d %8d %lu %d %p %d%n",
2084
		bucket, src, srcp, dest, destp, sp->sk_state,
2085 2086
		sk_wmem_alloc_get(sp),
		sk_rmem_alloc_get(sp),
2087
		0, 0L, 0, sock_i_uid(sp), 0, sock_i_ino(sp),
E
Eric Dumazet 已提交
2088 2089
		atomic_read(&sp->sk_refcnt), sp,
		atomic_read(&sp->sk_drops), len);
2090 2091 2092 2093 2094 2095 2096 2097
}

int udp4_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 "
E
Eric Dumazet 已提交
2098
			   "inode ref pointer drops");
2099 2100
	else {
		struct udp_iter_state *state = seq->private;
2101
		int len;
2102

2103
		udp4_format_sock(v, seq, state->bucket, &len);
E
Eric Dumazet 已提交
2104
		seq_printf(seq, "%*s\n", 127 - len, "");
2105 2106 2107 2108 2109 2110 2111 2112
	}
	return 0;
}

/* ------------------------------------------------------------------------ */
static struct udp_seq_afinfo udp4_seq_afinfo = {
	.name		= "udp",
	.family		= AF_INET,
2113
	.udp_table	= &udp_table,
2114 2115 2116
	.seq_fops	= {
		.owner	=	THIS_MODULE,
	},
2117 2118 2119
	.seq_ops	= {
		.show		= udp4_seq_show,
	},
2120 2121
};

2122
static int __net_init udp4_proc_init_net(struct net *net)
2123 2124 2125 2126
{
	return udp_proc_register(net, &udp4_seq_afinfo);
}

2127
static void __net_exit udp4_proc_exit_net(struct net *net)
2128 2129 2130 2131 2132 2133 2134 2135 2136
{
	udp_proc_unregister(net, &udp4_seq_afinfo);
}

static struct pernet_operations udp4_net_ops = {
	.init = udp4_proc_init_net,
	.exit = udp4_proc_exit_net,
};

2137 2138
int __init udp4_proc_init(void)
{
2139
	return register_pernet_subsys(&udp4_net_ops);
2140 2141 2142 2143
}

void udp4_proc_exit(void)
{
2144
	unregister_pernet_subsys(&udp4_net_ops);
2145
}
L
Linus Torvalds 已提交
2146 2147
#endif /* CONFIG_PROC_FS */

2148 2149
static __initdata unsigned long uhash_entries;
static int __init set_uhash_entries(char *str)
2150
{
2151 2152 2153 2154 2155 2156 2157 2158
	if (!str)
		return 0;
	uhash_entries = simple_strtoul(str, &str, 0);
	if (uhash_entries && uhash_entries < UDP_HTABLE_SIZE_MIN)
		uhash_entries = UDP_HTABLE_SIZE_MIN;
	return 1;
}
__setup("uhash_entries=", set_uhash_entries);
2159

2160 2161 2162 2163 2164 2165
void __init udp_table_init(struct udp_table *table, const char *name)
{
	unsigned int i;

	if (!CONFIG_BASE_SMALL)
		table->hash = alloc_large_system_hash(name,
2166
			2 * sizeof(struct udp_hslot),
2167 2168 2169 2170 2171 2172 2173 2174 2175 2176 2177
			uhash_entries,
			21, /* one slot per 2 MB */
			0,
			&table->log,
			&table->mask,
			64 * 1024);
	/*
	 * Make sure hash table has the minimum size
	 */
	if (CONFIG_BASE_SMALL || table->mask < UDP_HTABLE_SIZE_MIN - 1) {
		table->hash = kmalloc(UDP_HTABLE_SIZE_MIN *
2178
				      2 * sizeof(struct udp_hslot), GFP_KERNEL);
2179 2180 2181 2182 2183
		if (!table->hash)
			panic(name);
		table->log = ilog2(UDP_HTABLE_SIZE_MIN);
		table->mask = UDP_HTABLE_SIZE_MIN - 1;
	}
2184
	table->hash2 = table->hash + (table->mask + 1);
2185
	for (i = 0; i <= table->mask; i++) {
2186
		INIT_HLIST_NULLS_HEAD(&table->hash[i].head, i);
E
Eric Dumazet 已提交
2187
		table->hash[i].count = 0;
2188 2189
		spin_lock_init(&table->hash[i].lock);
	}
2190 2191 2192 2193 2194
	for (i = 0; i <= table->mask; i++) {
		INIT_HLIST_NULLS_HEAD(&table->hash2[i].head, i);
		table->hash2[i].count = 0;
		spin_lock_init(&table->hash2[i].lock);
	}
2195 2196
}

H
Hideo Aoki 已提交
2197 2198
void __init udp_init(void)
{
2199
	unsigned long nr_pages, limit;
H
Hideo Aoki 已提交
2200

2201
	udp_table_init(&udp_table, "UDP");
H
Hideo Aoki 已提交
2202 2203 2204 2205
	/* Set the pressure threshold up by the same strategy of TCP. It is a
	 * fraction of global memory that is up to 1/2 at 256 MB, decreasing
	 * toward zero with the amount of memory, with a floor of 128 pages.
	 */
2206 2207 2208
	nr_pages = totalram_pages - totalhigh_pages;
	limit = min(nr_pages, 1UL<<(28-PAGE_SHIFT)) >> (20-PAGE_SHIFT);
	limit = (limit * (nr_pages >> (20-PAGE_SHIFT))) >> (PAGE_SHIFT-11);
H
Hideo Aoki 已提交
2209 2210 2211 2212 2213 2214 2215 2216 2217
	limit = max(limit, 128UL);
	sysctl_udp_mem[0] = limit / 4 * 3;
	sysctl_udp_mem[1] = limit;
	sysctl_udp_mem[2] = sysctl_udp_mem[0] * 2;

	sysctl_udp_rmem_min = SK_MEM_QUANTUM;
	sysctl_udp_wmem_min = SK_MEM_QUANTUM;
}

2218 2219 2220 2221 2222 2223 2224 2225 2226 2227 2228 2229 2230 2231 2232 2233 2234 2235 2236
int udp4_ufo_send_check(struct sk_buff *skb)
{
	const struct iphdr *iph;
	struct udphdr *uh;

	if (!pskb_may_pull(skb, sizeof(*uh)))
		return -EINVAL;

	iph = ip_hdr(skb);
	uh = udp_hdr(skb);

	uh->check = ~csum_tcpudp_magic(iph->saddr, iph->daddr, skb->len,
				       IPPROTO_UDP, 0);
	skb->csum_start = skb_transport_header(skb) - skb->head;
	skb->csum_offset = offsetof(struct udphdr, check);
	skb->ip_summed = CHECKSUM_PARTIAL;
	return 0;
}

2237
struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb, u32 features)
2238 2239 2240 2241 2242 2243 2244 2245 2246 2247 2248 2249 2250 2251 2252 2253 2254 2255 2256 2257 2258 2259 2260 2261 2262 2263 2264
{
	struct sk_buff *segs = ERR_PTR(-EINVAL);
	unsigned int mss;
	int offset;
	__wsum csum;

	mss = skb_shinfo(skb)->gso_size;
	if (unlikely(skb->len <= mss))
		goto out;

	if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
		/* Packet is from an untrusted source, reset gso_segs. */
		int type = skb_shinfo(skb)->gso_type;

		if (unlikely(type & ~(SKB_GSO_UDP | SKB_GSO_DODGY) ||
			     !(type & (SKB_GSO_UDP))))
			goto out;

		skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);

		segs = NULL;
		goto out;
	}

	/* Do software UFO. Complete and fill in the UDP checksum as HW cannot
	 * do checksum of UDP packets sent as multiple IP fragments.
	 */
2265
	offset = skb_checksum_start_offset(skb);
E
Eric Dumazet 已提交
2266
	csum = skb_checksum(skb, offset, skb->len - offset, 0);
2267 2268 2269 2270 2271 2272 2273 2274 2275 2276 2277 2278
	offset += skb->csum_offset;
	*(__sum16 *)(skb->data + offset) = csum_fold(csum);
	skb->ip_summed = CHECKSUM_NONE;

	/* Fragment the skb. IP headers of the fragments are updated in
	 * inet_gso_segment()
	 */
	segs = skb_segment(skb, features);
out:
	return segs;
}