udp.c 57.6 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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#define pr_fmt(fmt) "UDP: " fmt

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#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 <trace/events/udp.h>
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#include <linux/static_key.h>
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#include <trace/events/skb.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-dependent hash value in secondary hash chains,
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 *                   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;
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		unsigned int 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
 */
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struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr,
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		__be16 sport, __be32 daddr, __be16 dport,
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		int dif, struct udp_table *udptable)
454
{
455
	struct sock *sk, *result;
456
	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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462
	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();
516 517
	return result;
}
518
EXPORT_SYMBOL_GPL(__udp4_lib_lookup);
519

520 521
static inline struct sock *__udp4_lib_lookup_skb(struct sk_buff *skb,
						 __be16 sport, __be16 dport,
522
						 struct udp_table *udptable)
523
{
524
	struct sock *sk;
525 526
	const struct iphdr *iph = ip_hdr(skb);

527 528 529
	if (unlikely(sk = skb_steal_sock(skb)))
		return sk;
	else
E
Eric Dumazet 已提交
530
		return __udp4_lib_lookup(dev_net(skb_dst(skb)->dev), iph->saddr, sport,
531 532
					 iph->daddr, dport, inet_iif(skb),
					 udptable);
533 534
}

535 536 537
struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
			     __be32 daddr, __be16 dport, int dif)
{
538
	return __udp4_lib_lookup(net, saddr, sport, daddr, dport, dif, &udp_table);
539 540 541
}
EXPORT_SYMBOL_GPL(udp4_lib_lookup);

542
static inline struct sock *udp_v4_mcast_next(struct net *net, struct sock *sk,
543 544 545 546
					     __be16 loc_port, __be32 loc_addr,
					     __be16 rmt_port, __be32 rmt_addr,
					     int dif)
{
547
	struct hlist_nulls_node *node;
548 549 550
	struct sock *s = sk;
	unsigned short hnum = ntohs(loc_port);

551
	sk_nulls_for_each_from(s, node) {
552 553
		struct inet_sock *inet = inet_sk(s);

554 555 556 557 558 559 560
		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) ||
561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582
		    (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.
 */

583
void __udp4_lib_err(struct sk_buff *skb, u32 info, struct udp_table *udptable)
584 585
{
	struct inet_sock *inet;
586
	const struct iphdr *iph = (const struct iphdr *)skb->data;
E
Eric Dumazet 已提交
587
	struct udphdr *uh = (struct udphdr *)(skb->data+(iph->ihl<<2));
588 589 590 591 592
	const int type = icmp_hdr(skb)->type;
	const int code = icmp_hdr(skb)->code;
	struct sock *sk;
	int harderr;
	int err;
593
	struct net *net = dev_net(skb->dev);
594

595
	sk = __udp4_lib_lookup(net, iph->daddr, uh->dest,
596 597
			iph->saddr, uh->source, skb->dev->ifindex, udptable);
	if (sk == NULL) {
598
		ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618
		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 */
619
			ipv4_sk_update_pmtu(skb, sk, info);
620 621 622 623 624 625 626 627 628 629 630 631 632
			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;
633 634 635
	case ICMP_REDIRECT:
		ipv4_sk_redirect(skb, sk);
		break;
636 637 638 639 640 641 642 643 644
	}

	/*
	 *      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;
645
	} else
E
Eric Dumazet 已提交
646
		ip_icmp_error(sk, skb, err, uh->dest, info, (u8 *)(uh+1));
647

648 649 650 651 652 653 654 655
	sk->sk_err = err;
	sk->sk_error_report(sk);
out:
	sock_put(sk);
}

void udp_err(struct sk_buff *skb, u32 info)
{
656
	__udp4_lib_err(skb, info, &udp_table);
657 658 659 660 661
}

/*
 * Throw away all pending data and cancel the corking. Socket is locked.
 */
662
void udp_flush_pending_frames(struct sock *sk)
663 664 665 666 667 668 669 670 671
{
	struct udp_sock *up = udp_sk(sk);

	if (up->pending) {
		up->len = 0;
		up->pending = 0;
		ip_flush_pending_frames(sk);
	}
}
672
EXPORT_SYMBOL(udp_flush_pending_frames);
673 674

/**
H
Herbert Xu 已提交
675
 * 	udp4_hwcsum  -  handle outgoing HW checksumming
676 677
 * 	@skb: 	sk_buff containing the filled-in UDP header
 * 	        (checksum field must be zeroed out)
H
Herbert Xu 已提交
678 679
 *	@src:	source IP address
 *	@dst:	destination IP address
680
 */
H
Herbert Xu 已提交
681
static void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst)
682 683
{
	struct udphdr *uh = udp_hdr(skb);
H
Herbert Xu 已提交
684 685 686 687
	struct sk_buff *frags = skb_shinfo(skb)->frag_list;
	int offset = skb_transport_offset(skb);
	int len = skb->len - offset;
	int hlen = len;
688 689
	__wsum csum = 0;

H
Herbert Xu 已提交
690
	if (!frags) {
691 692 693 694 695
		/*
		 * 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
696 697
		uh->check = ~csum_tcpudp_magic(src, dst, len,
					       IPPROTO_UDP, 0);
698 699 700 701 702 703
	} 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
704 705 706 707
		do {
			csum = csum_add(csum, frags->csum);
			hlen -= frags->len;
		} while ((frags = frags->next));
708

H
Herbert Xu 已提交
709
		csum = skb_checksum(skb, offset, hlen, csum);
710 711 712 713 714 715 716 717
		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;
	}
}

718
static int udp_send_skb(struct sk_buff *skb, struct flowi4 *fl4)
719
{
H
Herbert Xu 已提交
720
	struct sock *sk = skb->sk;
721 722 723 724
	struct inet_sock *inet = inet_sk(sk);
	struct udphdr *uh;
	int err = 0;
	int is_udplite = IS_UDPLITE(sk);
H
Herbert Xu 已提交
725 726
	int offset = skb_transport_offset(skb);
	int len = skb->len - offset;
727 728 729 730 731 732
	__wsum csum = 0;

	/*
	 * Create a UDP header
	 */
	uh = udp_hdr(skb);
H
Herbert Xu 已提交
733
	uh->source = inet->inet_sport;
734
	uh->dest = fl4->fl4_dport;
H
Herbert Xu 已提交
735
	uh->len = htons(len);
736 737 738
	uh->check = 0;

	if (is_udplite)  				 /*     UDP-Lite      */
H
Herbert Xu 已提交
739
		csum = udplite_csum(skb);
740 741 742 743 744 745 746 747

	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 */

748
		udp4_hwcsum(skb, fl4->saddr, fl4->daddr);
749 750
		goto send;

H
Herbert Xu 已提交
751 752
	} else
		csum = udp_csum(skb);
753 754

	/* add protocol-dependent pseudo-header */
755
	uh->check = csum_tcpudp_magic(fl4->saddr, fl4->daddr, len,
E
Eric Dumazet 已提交
756
				      sk->sk_protocol, csum);
757 758 759 760
	if (uh->check == 0)
		uh->check = CSUM_MANGLED_0;

send:
H
Herbert Xu 已提交
761
	err = ip_send_skb(skb);
E
Eric Dumazet 已提交
762 763 764 765 766 767 768 769 770
	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
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);
D
David S. Miller 已提交
781
	struct flowi4 *fl4 = &inet->cork.fl.u.ip4;
H
Herbert Xu 已提交
782 783 784
	struct sk_buff *skb;
	int err = 0;

785
	skb = ip_finish_skb(sk, fl4);
H
Herbert Xu 已提交
786 787 788
	if (!skb)
		goto out;

789
	err = udp_send_skb(skb, fl4);
H
Herbert Xu 已提交
790

791 792 793 794 795 796 797 798 799 800 801
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);
802
	struct flowi4 fl4_stack;
D
David S. Miller 已提交
803
	struct flowi4 *fl4;
804 805 806 807 808 809 810 811 812 813 814
	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
815
	struct sk_buff *skb;
816
	struct ip_options_data opt_copy;
817 818 819 820 821 822 823 824

	if (len > 0xFFFF)
		return -EMSGSIZE;

	/*
	 *	Check the flags.
	 */

E
Eric Dumazet 已提交
825
	if (msg->msg_flags & MSG_OOB) /* Mirror BSD error message compatibility */
826 827 828
		return -EOPNOTSUPP;

	ipc.opt = NULL;
829
	ipc.tx_flags = 0;
830

H
Herbert Xu 已提交
831 832
	getfrag = is_udplite ? udplite_getfrag : ip_generic_getfrag;

833
	fl4 = &inet->cork.fl.u.ip4;
834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854
	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) {
D
Daniel Baluta 已提交
855
		struct sockaddr_in *usin = (struct sockaddr_in *)msg->msg_name;
856 857 858 859 860 861 862 863 864 865 866 867 868 869
		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
870 871
		daddr = inet->inet_daddr;
		dport = inet->inet_dport;
872 873 874 875 876
		/* 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
877
	ipc.addr = inet->inet_saddr;
878 879

	ipc.oif = sk->sk_bound_dev_if;
880
	err = sock_tx_timestamp(sk, &ipc.tx_flags);
881 882
	if (err)
		return err;
883
	if (msg->msg_controllen) {
884
		err = ip_cmsg_send(sock_net(sk), msg, &ipc);
885 886 887 888 889 890
		if (err)
			return err;
		if (ipc.opt)
			free = 1;
		connected = 0;
	}
891 892 893 894 895 896 897 898 899 900 901 902
	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();
	}
903 904 905 906

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

907
	if (ipc.opt && ipc.opt->opt.srr) {
908 909
		if (!daddr)
			return -EINVAL;
910
		faddr = ipc.opt->opt.faddr;
911 912 913 914 915
		connected = 0;
	}
	tos = RT_TOS(inet->tos);
	if (sock_flag(sk, SOCK_LOCALROUTE) ||
	    (msg->msg_flags & MSG_DONTROUTE) ||
916
	    (ipc.opt && ipc.opt->opt.is_strictroute)) {
917 918 919 920 921 922 923 924 925 926
		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;
927 928
	} else if (!ipc.oif)
		ipc.oif = inet->uc_index;
929 930

	if (connected)
E
Eric Dumazet 已提交
931
		rt = (struct rtable *)sk_dst_check(sk, 0);
932 933

	if (rt == NULL) {
934 935
		struct net *net = sock_net(sk);

936 937
		fl4 = &fl4_stack;
		flowi4_init_output(fl4, ipc.oif, sk->sk_mark, tos,
938 939 940 941
				   RT_SCOPE_UNIVERSE, sk->sk_protocol,
				   inet_sk_flowi_flags(sk)|FLOWI_FLAG_CAN_SLEEP,
				   faddr, saddr, dport, inet->inet_sport);

942 943
		security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
		rt = ip_route_output_flow(net, fl4, sk);
944 945
		if (IS_ERR(rt)) {
			err = PTR_ERR(rt);
946
			rt = NULL;
947
			if (err == -ENETUNREACH)
948
				IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES);
949 950 951 952 953 954 955 956
			goto out;
		}

		err = -EACCES;
		if ((rt->rt_flags & RTCF_BROADCAST) &&
		    !sock_flag(sk, SOCK_BROADCAST))
			goto out;
		if (connected)
957
			sk_dst_set(sk, dst_clone(&rt->dst));
958 959 960 961 962 963
	}

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

964
	saddr = fl4->saddr;
965
	if (!ipc.addr)
966
		daddr = ipc.addr = fl4->daddr;
967

H
Herbert Xu 已提交
968 969
	/* Lockless fast path for the non-corking case. */
	if (!corkreq) {
970
		skb = ip_make_skb(sk, fl4, getfrag, msg->msg_iov, ulen,
H
Herbert Xu 已提交
971 972 973 974
				  sizeof(struct udphdr), &ipc, &rt,
				  msg->msg_flags);
		err = PTR_ERR(skb);
		if (skb && !IS_ERR(skb))
975
			err = udp_send_skb(skb, fl4);
H
Herbert Xu 已提交
976 977 978
		goto out;
	}

979 980 981 982 983 984
	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);

985
		LIMIT_NETDEBUG(KERN_DEBUG pr_fmt("cork app bug 2\n"));
986 987 988 989 990 991
		err = -EINVAL;
		goto out;
	}
	/*
	 *	Now cork the socket to pend data.
	 */
D
David S. Miller 已提交
992 993 994
	fl4 = &inet->cork.fl.u.ip4;
	fl4->daddr = daddr;
	fl4->saddr = saddr;
995 996
	fl4->fl4_dport = dport;
	fl4->fl4_sport = inet->inet_sport;
997 998 999 1000
	up->pending = AF_INET;

do_append_data:
	up->len += ulen;
1001 1002 1003
	err = ip_append_data(sk, fl4, getfrag, msg->msg_iov, ulen,
			     sizeof(struct udphdr), &ipc, &rt,
			     corkreq ? msg->msg_flags|MSG_MORE : msg->msg_flags);
1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025
	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)) {
1026 1027
		UDP_INC_STATS_USER(sock_net(sk),
				UDP_MIB_SNDBUFERRORS, is_udplite);
1028 1029 1030 1031
	}
	return err;

do_confirm:
1032
	dst_confirm(&rt->dst);
1033 1034 1035 1036 1037
	if (!(msg->msg_flags&MSG_PROBE) || len)
		goto back_from_confirm;
	err = 0;
	goto out;
}
E
Eric Dumazet 已提交
1038
EXPORT_SYMBOL(udp_sendmsg);
1039 1040 1041 1042

int udp_sendpage(struct sock *sk, struct page *page, int offset,
		 size_t size, int flags)
{
1043
	struct inet_sock *inet = inet_sk(sk);
1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063
	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);

1064
		LIMIT_NETDEBUG(KERN_DEBUG pr_fmt("udp cork app bug 3\n"));
1065 1066 1067
		return -EINVAL;
	}

1068 1069
	ret = ip_append_page(sk, &inet->cork.fl.u.ip4,
			     page, offset, size, flags);
1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089
	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
1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110

/**
 *	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
1111
		atomic_inc(&sk->sk_drops);
E
Eric Dumazet 已提交
1112 1113 1114 1115 1116 1117 1118
		__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)) {
1119 1120
		bool slow = lock_sock_fast(sk);

E
Eric Dumazet 已提交
1121 1122
		__skb_queue_purge(&list_kill);
		sk_mem_reclaim_partial(sk);
1123
		unlock_sock_fast(sk, slow);
E
Eric Dumazet 已提交
1124 1125 1126 1127
	}
	return res;
}

L
Linus Torvalds 已提交
1128 1129 1130
/*
 *	IOCTL requests applicable to the UDP protocol
 */
1131

L
Linus Torvalds 已提交
1132 1133
int udp_ioctl(struct sock *sk, int cmd, unsigned long arg)
{
1134 1135
	switch (cmd) {
	case SIOCOUTQ:
L
Linus Torvalds 已提交
1136
	{
1137 1138
		int amount = sk_wmem_alloc_get(sk);

1139 1140
		return put_user(amount, (int __user *)arg);
	}
L
Linus Torvalds 已提交
1141

1142 1143
	case SIOCINQ:
	{
E
Eric Dumazet 已提交
1144
		unsigned int amount = first_packet_length(sk);
1145

E
Eric Dumazet 已提交
1146
		if (amount)
1147 1148 1149 1150 1151
			/*
			 * We will only return the amount
			 * of this packet since that is all
			 * that will be read.
			 */
E
Eric Dumazet 已提交
1152 1153
			amount -= sizeof(struct udphdr);

1154 1155
		return put_user(amount, (int __user *)arg);
	}
L
Linus Torvalds 已提交
1156

1157 1158
	default:
		return -ENOIOCTLCMD;
L
Linus Torvalds 已提交
1159
	}
1160 1161

	return 0;
L
Linus Torvalds 已提交
1162
}
E
Eric Dumazet 已提交
1163
EXPORT_SYMBOL(udp_ioctl);
L
Linus Torvalds 已提交
1164

1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175
/*
 * 	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;
1176
	unsigned int ulen, copied;
1177
	int peeked, off = 0;
1178 1179
	int err;
	int is_udplite = IS_UDPLITE(sk);
1180
	bool slow;
1181 1182 1183 1184 1185

	/*
	 *	Check any passed addresses
	 */
	if (addr_len)
E
Eric Dumazet 已提交
1186
		*addr_len = sizeof(*sin);
1187 1188 1189 1190 1191 1192

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

try_again:
	skb = __skb_recv_datagram(sk, flags | (noblock ? MSG_DONTWAIT : 0),
1193
				  &peeked, &off, &err);
1194 1195 1196 1197
	if (!skb)
		goto out;

	ulen = skb->len - sizeof(struct udphdr);
1198 1199 1200 1201
	copied = len;
	if (copied > ulen)
		copied = ulen;
	else if (copied < ulen)
1202 1203 1204 1205 1206 1207 1208 1209
		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.
	 */

1210
	if (copied < ulen || UDP_SKB_CB(skb)->partial_cov) {
1211 1212 1213 1214 1215 1216
		if (udp_lib_checksum_complete(skb))
			goto csum_copy_err;
	}

	if (skb_csum_unnecessary(skb))
		err = skb_copy_datagram_iovec(skb, sizeof(struct udphdr),
1217
					      msg->msg_iov, copied);
1218
	else {
E
Eric Dumazet 已提交
1219 1220 1221
		err = skb_copy_and_csum_datagram_iovec(skb,
						       sizeof(struct udphdr),
						       msg->msg_iov);
1222 1223 1224 1225 1226

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

1227 1228
	if (unlikely(err)) {
		trace_kfree_skb(skb, udp_recvmsg);
1229
		goto out_free;
1230
	}
1231 1232

	if (!peeked)
1233 1234
		UDP_INC_STATS_USER(sock_net(sk),
				UDP_MIB_INDATAGRAMS, is_udplite);
1235

1236
	sock_recv_ts_and_drops(msg, sk, skb);
1237 1238

	/* Copy the address. */
E
Eric Dumazet 已提交
1239
	if (sin) {
1240 1241 1242 1243 1244 1245 1246 1247
		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);

1248
	err = copied;
1249 1250 1251 1252
	if (flags & MSG_TRUNC)
		err = ulen;

out_free:
1253
	skb_free_datagram_locked(sk, skb);
1254 1255 1256 1257
out:
	return err;

csum_copy_err:
1258
	slow = lock_sock_fast(sk);
1259
	if (!skb_kill_datagram(sk, skb, flags))
1260
		UDP_INC_STATS_USER(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
1261
	unlock_sock_fast(sk, slow);
1262 1263 1264

	if (noblock)
		return -EAGAIN;
1265 1266 1267

	/* starting over for a new packet */
	msg->msg_flags &= ~MSG_TRUNC;
1268 1269 1270 1271
	goto try_again;
}


L
Linus Torvalds 已提交
1272 1273 1274 1275 1276 1277
int udp_disconnect(struct sock *sk, int flags)
{
	struct inet_sock *inet = inet_sk(sk);
	/*
	 *	1003.1g - break association.
	 */
1278

L
Linus Torvalds 已提交
1279
	sk->sk_state = TCP_CLOSE;
E
Eric Dumazet 已提交
1280 1281
	inet->inet_daddr = 0;
	inet->inet_dport = 0;
1282
	sock_rps_reset_rxhash(sk);
L
Linus Torvalds 已提交
1283 1284 1285 1286 1287 1288
	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
1289
		inet->inet_sport = 0;
L
Linus Torvalds 已提交
1290 1291 1292 1293
	}
	sk_dst_reset(sk);
	return 0;
}
E
Eric Dumazet 已提交
1294
EXPORT_SYMBOL(udp_disconnect);
L
Linus Torvalds 已提交
1295

1296 1297
void udp_lib_unhash(struct sock *sk)
{
1298 1299
	if (sk_hashed(sk)) {
		struct udp_table *udptable = sk->sk_prot->h.udp_table;
1300 1301 1302 1303 1304
		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);
1305

1306 1307
		spin_lock_bh(&hslot->lock);
		if (sk_nulls_del_node_init_rcu(sk)) {
E
Eric Dumazet 已提交
1308
			hslot->count--;
E
Eric Dumazet 已提交
1309
			inet_sk(sk)->inet_num = 0;
1310
			sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
1311 1312 1313 1314 1315

			spin_lock(&hslot2->lock);
			hlist_nulls_del_init_rcu(&udp_sk(sk)->udp_portaddr_node);
			hslot2->count--;
			spin_unlock(&hslot2->lock);
1316 1317
		}
		spin_unlock_bh(&hslot->lock);
1318 1319 1320 1321
	}
}
EXPORT_SYMBOL(udp_lib_unhash);

E
Eric Dumazet 已提交
1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364
/*
 * 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
1365 1366
static int __udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
{
T
Tom Herbert 已提交
1367
	int rc;
E
Eric Dumazet 已提交
1368

T
Tom Herbert 已提交
1369
	if (inet_sk(sk)->inet_daddr)
1370
		sock_rps_save_rxhash(sk, skb);
T
Tom Herbert 已提交
1371

1372
	rc = sock_queue_rcv_skb(sk, skb);
E
Eric Dumazet 已提交
1373 1374
	if (rc < 0) {
		int is_udplite = IS_UDPLITE(sk);
H
Herbert Xu 已提交
1375 1376

		/* Note that an ENOMEM error is charged twice */
E
Eric Dumazet 已提交
1377
		if (rc == -ENOMEM)
H
Herbert Xu 已提交
1378 1379
			UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_RCVBUFERRORS,
					 is_udplite);
E
Eric Dumazet 已提交
1380 1381
		UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
		kfree_skb(skb);
1382
		trace_udp_fail_queue_rcv_skb(rc, sk);
E
Eric Dumazet 已提交
1383
		return -1;
H
Herbert Xu 已提交
1384 1385 1386 1387 1388 1389
	}

	return 0;

}

1390 1391 1392 1393 1394 1395 1396 1397
static struct static_key udp_encap_needed __read_mostly;
void udp_encap_enable(void)
{
	if (!static_key_enabled(&udp_encap_needed))
		static_key_slow_inc(&udp_encap_needed);
}
EXPORT_SYMBOL(udp_encap_enable);

1398 1399 1400 1401 1402 1403 1404 1405
/* 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
1406
int udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418
{
	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);

1419
	if (static_key_false(&udp_encap_needed) && up->encap_type) {
1420 1421
		int (*encap_rcv)(struct sock *sk, struct sk_buff *skb);

1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433
		/*
		 * 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 */
1434 1435
		encap_rcv = ACCESS_ONCE(up->encap_rcv);
		if (skb->len > sizeof(struct udphdr) && encap_rcv != NULL) {
1436 1437
			int ret;

1438
			ret = encap_rcv(sk, skb);
1439
			if (ret <= 0) {
1440 1441
				UDP_INC_STATS_BH(sock_net(sk),
						 UDP_MIB_INDATAGRAMS,
1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466
						 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  */
1467 1468
			LIMIT_NETDEBUG(KERN_WARNING "UDPLite: partial coverage %d while full coverage %d requested\n",
				       UDP_SKB_CB(skb)->cscov, skb->len);
1469 1470 1471 1472 1473 1474 1475 1476 1477
			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) {
1478 1479
			LIMIT_NETDEBUG(KERN_WARNING "UDPLite: coverage %d too small, need min %d\n",
				       UDP_SKB_CB(skb)->cscov, up->pcrlen);
1480 1481 1482 1483
			goto drop;
		}
	}

1484 1485 1486
	if (rcu_access_pointer(sk->sk_filter) &&
	    udp_lib_checksum_complete(skb))
		goto drop;
1487

1488

1489
	if (sk_rcvqueues_full(sk, skb, sk->sk_rcvbuf))
1490 1491
		goto drop;

H
Herbert Xu 已提交
1492
	rc = 0;
1493

1494
	ipv4_pktinfo_prepare(skb);
H
Herbert Xu 已提交
1495 1496 1497
	bh_lock_sock(sk);
	if (!sock_owned_by_user(sk))
		rc = __udp_queue_rcv_skb(sk, skb);
1498
	else if (sk_add_backlog(sk, skb, sk->sk_rcvbuf)) {
Z
Zhu Yi 已提交
1499 1500 1501
		bh_unlock_sock(sk);
		goto drop;
	}
H
Herbert Xu 已提交
1502 1503 1504
	bh_unlock_sock(sk);

	return rc;
1505 1506

drop:
1507
	UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
E
Eric Dumazet 已提交
1508
	atomic_inc(&sk->sk_drops);
1509 1510 1511 1512
	kfree_skb(skb);
	return -1;
}

1513 1514 1515 1516 1517 1518

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;
1519
	struct sock *sk;
1520 1521

	for (i = 0; i < count; i++) {
1522
		sk = stack[i];
1523 1524 1525
		if (likely(skb1 == NULL))
			skb1 = (i == final) ? skb : skb_clone(skb, GFP_ATOMIC);

1526 1527 1528 1529 1530 1531 1532 1533 1534
		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)
1535 1536 1537 1538 1539 1540
			skb1 = NULL;
	}
	if (unlikely(skb1))
		kfree_skb(skb1);
}

1541 1542 1543
/*
 *	Multicasts and broadcasts go to each listener.
 *
1544
 *	Note: called only from the BH handler context.
1545
 */
1546
static int __udp4_lib_mcast_deliver(struct net *net, struct sk_buff *skb,
1547 1548
				    struct udphdr  *uh,
				    __be32 saddr, __be32 daddr,
1549
				    struct udp_table *udptable)
1550
{
1551
	struct sock *sk, *stack[256 / sizeof(struct sock *)];
1552
	struct udp_hslot *hslot = udp_hashslot(udptable, net, ntohs(uh->dest));
1553
	int dif;
1554
	unsigned int i, count = 0;
1555

1556
	spin_lock(&hslot->lock);
1557
	sk = sk_nulls_head(&hslot->head);
1558
	dif = skb->dev->ifindex;
1559
	sk = udp_v4_mcast_next(net, sk, uh->dest, daddr, uh->source, saddr, dif);
1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576
	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]);

1577
	spin_unlock(&hslot->lock);
1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589

	/*
	 * 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);
	}
1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616
	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
1617
		if (!csum_tcpudp_magic(iph->saddr, iph->daddr, skb->len,
1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633 1634
				      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.
 */

1635
int __udp4_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
1636 1637 1638
		   int proto)
{
	struct sock *sk;
1639
	struct udphdr *uh;
1640
	unsigned short ulen;
E
Eric Dumazet 已提交
1641
	struct rtable *rt = skb_rtable(skb);
1642
	__be32 saddr, daddr;
1643
	struct net *net = dev_net(skb->dev);
1644 1645 1646 1647 1648 1649 1650

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

1651
	uh   = udp_hdr(skb);
1652
	ulen = ntohs(uh->len);
1653 1654 1655
	saddr = ip_hdr(skb)->saddr;
	daddr = ip_hdr(skb)->daddr;

1656 1657 1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669
	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))
1670 1671
		return __udp4_lib_mcast_deliver(net, skb, uh,
				saddr, daddr, udptable);
1672

1673
	sk = __udp4_lib_lookup_skb(skb, uh->source, uh->dest, udptable);
1674 1675

	if (sk != NULL) {
H
Herbert Xu 已提交
1676
		int ret = udp_queue_rcv_skb(sk, skb);
1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694
		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;

1695
	UDP_INC_STATS_BH(net, UDP_MIB_NOPORTS, proto == IPPROTO_UDPLITE);
1696 1697 1698 1699 1700 1701 1702 1703 1704 1705
	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:
1706
	LIMIT_NETDEBUG(KERN_DEBUG "UDP%s: short packet: From %pI4:%u %d/%d to %pI4:%u\n",
1707 1708 1709 1710
		       proto == IPPROTO_UDPLITE ? "Lite" : "",
		       &saddr, ntohs(uh->source),
		       ulen, skb->len,
		       &daddr, ntohs(uh->dest));
1711 1712 1713 1714 1715 1716 1717
	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).
	 */
1718
	LIMIT_NETDEBUG(KERN_DEBUG "UDP%s: bad checksum. From %pI4:%u to %pI4:%u ulen %d\n",
1719 1720
		       proto == IPPROTO_UDPLITE ? "Lite" : "",
		       &saddr, ntohs(uh->source), &daddr, ntohs(uh->dest),
1721 1722
		       ulen);
drop:
1723
	UDP_INC_STATS_BH(net, UDP_MIB_INERRORS, proto == IPPROTO_UDPLITE);
1724 1725 1726 1727 1728 1729
	kfree_skb(skb);
	return 0;
}

int udp_rcv(struct sk_buff *skb)
{
1730
	return __udp4_lib_rcv(skb, &udp_table, IPPROTO_UDP);
1731 1732
}

1733
void udp_destroy_sock(struct sock *sk)
1734
{
1735
	bool slow = lock_sock_fast(sk);
1736
	udp_flush_pending_frames(sk);
1737
	unlock_sock_fast(sk, slow);
1738 1739
}

L
Linus Torvalds 已提交
1740 1741 1742
/*
 *	Socket option code for UDP
 */
1743
int udp_lib_setsockopt(struct sock *sk, int level, int optname,
1744
		       char __user *optval, unsigned int optlen,
1745
		       int (*push_pending_frames)(struct sock *))
L
Linus Torvalds 已提交
1746 1747 1748 1749
{
	struct udp_sock *up = udp_sk(sk);
	int val;
	int err = 0;
W
Wang Chen 已提交
1750
	int is_udplite = IS_UDPLITE(sk);
L
Linus Torvalds 已提交
1751

E
Eric Dumazet 已提交
1752
	if (optlen < sizeof(int))
L
Linus Torvalds 已提交
1753 1754 1755 1756 1757
		return -EINVAL;

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

1758
	switch (optname) {
L
Linus Torvalds 已提交
1759 1760 1761 1762 1763 1764
	case UDP_CORK:
		if (val != 0) {
			up->corkflag = 1;
		} else {
			up->corkflag = 0;
			lock_sock(sk);
1765
			(*push_pending_frames)(sk);
L
Linus Torvalds 已提交
1766 1767 1768
			release_sock(sk);
		}
		break;
1769

L
Linus Torvalds 已提交
1770 1771 1772 1773 1774
	case UDP_ENCAP:
		switch (val) {
		case 0:
		case UDP_ENCAP_ESPINUDP:
		case UDP_ENCAP_ESPINUDP_NON_IKE:
1775 1776
			up->encap_rcv = xfrm4_udp_encap_rcv;
			/* FALLTHROUGH */
1777
		case UDP_ENCAP_L2TPINUDP:
L
Linus Torvalds 已提交
1778
			up->encap_type = val;
1779
			udp_encap_enable();
L
Linus Torvalds 已提交
1780 1781 1782 1783 1784 1785 1786
			break;
		default:
			err = -ENOPROTOOPT;
			break;
		}
		break;

1787 1788 1789 1790 1791 1792
	/*
	 * 	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
1793
		if (!is_udplite)         /* Disable the option on UDP sockets */
1794 1795 1796
			return -ENOPROTOOPT;
		if (val != 0 && val < 8) /* Illegal coverage: use default (8) */
			val = 8;
1797 1798
		else if (val > USHRT_MAX)
			val = USHRT_MAX;
1799 1800 1801 1802
		up->pcslen = val;
		up->pcflag |= UDPLITE_SEND_CC;
		break;

1803 1804
	/* 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
1805 1806
	 * used, this again means full checksum coverage.                     */
	case UDPLITE_RECV_CSCOV:
W
Wang Chen 已提交
1807
		if (!is_udplite)         /* Disable the option on UDP sockets */
1808 1809 1810
			return -ENOPROTOOPT;
		if (val != 0 && val < 8) /* Avoid silly minimal values.       */
			val = 8;
1811 1812
		else if (val > USHRT_MAX)
			val = USHRT_MAX;
1813 1814 1815 1816
		up->pcrlen = val;
		up->pcflag |= UDPLITE_RECV_CC;
		break;

L
Linus Torvalds 已提交
1817 1818 1819
	default:
		err = -ENOPROTOOPT;
		break;
1820
	}
L
Linus Torvalds 已提交
1821 1822 1823

	return err;
}
E
Eric Dumazet 已提交
1824
EXPORT_SYMBOL(udp_lib_setsockopt);
L
Linus Torvalds 已提交
1825

1826
int udp_setsockopt(struct sock *sk, int level, int optname,
1827
		   char __user *optval, unsigned int optlen)
1828 1829 1830 1831 1832 1833 1834 1835 1836
{
	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,
1837
			  char __user *optval, unsigned int optlen)
1838 1839 1840 1841 1842 1843 1844 1845
{
	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

1846 1847
int udp_lib_getsockopt(struct sock *sk, int level, int optname,
		       char __user *optval, int __user *optlen)
L
Linus Torvalds 已提交
1848 1849 1850 1851
{
	struct udp_sock *up = udp_sk(sk);
	int val, len;

E
Eric Dumazet 已提交
1852
	if (get_user(len, optlen))
L
Linus Torvalds 已提交
1853 1854 1855
		return -EFAULT;

	len = min_t(unsigned int, len, sizeof(int));
1856

1857
	if (len < 0)
L
Linus Torvalds 已提交
1858 1859
		return -EINVAL;

1860
	switch (optname) {
L
Linus Torvalds 已提交
1861 1862 1863 1864 1865 1866 1867 1868
	case UDP_CORK:
		val = up->corkflag;
		break;

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

1869 1870 1871 1872 1873 1874 1875 1876 1877 1878
	/* 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
1879 1880
	default:
		return -ENOPROTOOPT;
1881
	}
L
Linus Torvalds 已提交
1882

1883
	if (put_user(len, optlen))
1884
		return -EFAULT;
E
Eric Dumazet 已提交
1885
	if (copy_to_user(optval, &val, len))
L
Linus Torvalds 已提交
1886
		return -EFAULT;
1887
	return 0;
L
Linus Torvalds 已提交
1888
}
E
Eric Dumazet 已提交
1889
EXPORT_SYMBOL(udp_lib_getsockopt);
L
Linus Torvalds 已提交
1890

1891 1892 1893 1894 1895 1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907
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
1908 1909 1910 1911 1912 1913
/**
 * 	udp_poll - wait for a UDP event.
 *	@file - file struct
 *	@sock - socket
 *	@wait - poll table
 *
1914
 *	This is same as datagram poll, except for the special case of
L
Linus Torvalds 已提交
1915 1916 1917 1918 1919 1920 1921 1922 1923 1924
 *	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;
1925

L
Linus Torvalds 已提交
1926
	/* Check for false positives due to checksum errors */
E
Eric Dumazet 已提交
1927 1928 1929
	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
1930 1931

	return mask;
1932

L
Linus Torvalds 已提交
1933
}
E
Eric Dumazet 已提交
1934
EXPORT_SYMBOL(udp_poll);
L
Linus Torvalds 已提交
1935

1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948
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
1949
	.backlog_rcv	   = __udp_queue_rcv_skb,
1950 1951
	.hash		   = udp_lib_hash,
	.unhash		   = udp_lib_unhash,
E
Eric Dumazet 已提交
1952
	.rehash		   = udp_v4_rehash,
1953 1954 1955 1956 1957 1958
	.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),
1959
	.slab_flags	   = SLAB_DESTROY_BY_RCU,
1960
	.h.udp_table	   = &udp_table,
1961 1962 1963 1964
#ifdef CONFIG_COMPAT
	.compat_setsockopt = compat_udp_setsockopt,
	.compat_getsockopt = compat_udp_getsockopt,
#endif
1965
	.clear_sk	   = sk_prot_clear_portaddr_nulls,
1966
};
E
Eric Dumazet 已提交
1967
EXPORT_SYMBOL(udp_prot);
L
Linus Torvalds 已提交
1968 1969 1970 1971

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

1972
static struct sock *udp_get_first(struct seq_file *seq, int start)
L
Linus Torvalds 已提交
1973 1974 1975
{
	struct sock *sk;
	struct udp_iter_state *state = seq->private;
1976
	struct net *net = seq_file_net(seq);
L
Linus Torvalds 已提交
1977

1978 1979
	for (state->bucket = start; state->bucket <= state->udp_table->mask;
	     ++state->bucket) {
1980
		struct hlist_nulls_node *node;
1981
		struct udp_hslot *hslot = &state->udp_table->hash[state->bucket];
1982 1983 1984 1985

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

1986
		spin_lock_bh(&hslot->lock);
1987
		sk_nulls_for_each(sk, node, &hslot->head) {
1988
			if (!net_eq(sock_net(sk), net))
1989
				continue;
L
Linus Torvalds 已提交
1990 1991 1992
			if (sk->sk_family == state->family)
				goto found;
		}
1993
		spin_unlock_bh(&hslot->lock);
L
Linus Torvalds 已提交
1994 1995 1996 1997 1998 1999 2000 2001 2002
	}
	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;
2003
	struct net *net = seq_file_net(seq);
L
Linus Torvalds 已提交
2004 2005

	do {
2006
		sk = sk_nulls_next(sk);
2007
	} while (sk && (!net_eq(sock_net(sk), net) || sk->sk_family != state->family));
L
Linus Torvalds 已提交
2008

2009
	if (!sk) {
2010
		if (state->bucket <= state->udp_table->mask)
2011
			spin_unlock_bh(&state->udp_table->hash[state->bucket].lock);
2012
		return udp_get_first(seq, state->bucket + 1);
L
Linus Torvalds 已提交
2013 2014 2015 2016 2017 2018
	}
	return sk;
}

static struct sock *udp_get_idx(struct seq_file *seq, loff_t pos)
{
2019
	struct sock *sk = udp_get_first(seq, 0);
L
Linus Torvalds 已提交
2020 2021

	if (sk)
2022
		while (pos && (sk = udp_get_next(seq, sk)) != NULL)
L
Linus Torvalds 已提交
2023 2024 2025 2026 2027 2028
			--pos;
	return pos ? NULL : sk;
}

static void *udp_seq_start(struct seq_file *seq, loff_t *pos)
{
2029
	struct udp_iter_state *state = seq->private;
2030
	state->bucket = MAX_UDP_PORTS;
2031

2032
	return *pos ? udp_get_idx(seq, *pos-1) : SEQ_START_TOKEN;
L
Linus Torvalds 已提交
2033 2034 2035 2036 2037 2038
}

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

2039
	if (v == SEQ_START_TOKEN)
L
Linus Torvalds 已提交
2040 2041 2042 2043 2044 2045 2046 2047 2048 2049
		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)
{
2050 2051
	struct udp_iter_state *state = seq->private;

2052
	if (state->bucket <= state->udp_table->mask)
2053
		spin_unlock_bh(&state->udp_table->hash[state->bucket].lock);
L
Linus Torvalds 已提交
2054 2055
}

2056
int udp_seq_open(struct inode *inode, struct file *file)
L
Linus Torvalds 已提交
2057 2058
{
	struct udp_seq_afinfo *afinfo = PDE(inode)->data;
2059 2060
	struct udp_iter_state *s;
	int err;
2061

2062 2063 2064 2065
	err = seq_open_net(inode, file, &afinfo->seq_ops,
			   sizeof(struct udp_iter_state));
	if (err < 0)
		return err;
2066

2067
	s = ((struct seq_file *)file->private_data)->private;
L
Linus Torvalds 已提交
2068
	s->family		= afinfo->family;
2069
	s->udp_table		= afinfo->udp_table;
2070
	return err;
2071
}
2072
EXPORT_SYMBOL(udp_seq_open);
2073

L
Linus Torvalds 已提交
2074
/* ------------------------------------------------------------------------ */
2075
int udp_proc_register(struct net *net, struct udp_seq_afinfo *afinfo)
L
Linus Torvalds 已提交
2076 2077 2078 2079
{
	struct proc_dir_entry *p;
	int rc = 0;

2080 2081 2082 2083
	afinfo->seq_ops.start		= udp_seq_start;
	afinfo->seq_ops.next		= udp_seq_next;
	afinfo->seq_ops.stop		= udp_seq_stop;

2084
	p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
2085
			     afinfo->seq_fops, afinfo);
2086
	if (!p)
L
Linus Torvalds 已提交
2087 2088 2089
		rc = -ENOMEM;
	return rc;
}
E
Eric Dumazet 已提交
2090
EXPORT_SYMBOL(udp_proc_register);
L
Linus Torvalds 已提交
2091

2092
void udp_proc_unregister(struct net *net, struct udp_seq_afinfo *afinfo)
L
Linus Torvalds 已提交
2093
{
2094
	proc_net_remove(net, afinfo->name);
L
Linus Torvalds 已提交
2095
}
E
Eric Dumazet 已提交
2096
EXPORT_SYMBOL(udp_proc_unregister);
2097 2098

/* ------------------------------------------------------------------------ */
2099 2100
static void udp4_format_sock(struct sock *sp, struct seq_file *f,
		int bucket, int *len)
2101 2102
{
	struct inet_sock *inet = inet_sk(sp);
E
Eric Dumazet 已提交
2103 2104 2105 2106
	__be32 dest = inet->inet_daddr;
	__be32 src  = inet->inet_rcv_saddr;
	__u16 destp	  = ntohs(inet->inet_dport);
	__u16 srcp	  = ntohs(inet->inet_sport);
2107

2108
	seq_printf(f, "%5d: %08X:%04X %08X:%04X"
D
Dan Rosenberg 已提交
2109
		" %02X %08X:%08X %02X:%08lX %08X %5d %8d %lu %d %pK %d%n",
2110
		bucket, src, srcp, dest, destp, sp->sk_state,
2111 2112
		sk_wmem_alloc_get(sp),
		sk_rmem_alloc_get(sp),
2113
		0, 0L, 0, sock_i_uid(sp), 0, sock_i_ino(sp),
E
Eric Dumazet 已提交
2114 2115
		atomic_read(&sp->sk_refcnt), sp,
		atomic_read(&sp->sk_drops), len);
2116 2117 2118 2119 2120 2121 2122 2123
}

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
2124
			   "inode ref pointer drops");
2125 2126
	else {
		struct udp_iter_state *state = seq->private;
2127
		int len;
2128

2129
		udp4_format_sock(v, seq, state->bucket, &len);
E
Eric Dumazet 已提交
2130
		seq_printf(seq, "%*s\n", 127 - len, "");
2131 2132 2133 2134
	}
	return 0;
}

2135 2136 2137 2138 2139 2140 2141 2142
static const struct file_operations udp_afinfo_seq_fops = {
	.owner    = THIS_MODULE,
	.open     = udp_seq_open,
	.read     = seq_read,
	.llseek   = seq_lseek,
	.release  = seq_release_net
};

2143 2144 2145 2146
/* ------------------------------------------------------------------------ */
static struct udp_seq_afinfo udp4_seq_afinfo = {
	.name		= "udp",
	.family		= AF_INET,
2147
	.udp_table	= &udp_table,
2148
	.seq_fops	= &udp_afinfo_seq_fops,
2149 2150 2151
	.seq_ops	= {
		.show		= udp4_seq_show,
	},
2152 2153
};

2154
static int __net_init udp4_proc_init_net(struct net *net)
2155 2156 2157 2158
{
	return udp_proc_register(net, &udp4_seq_afinfo);
}

2159
static void __net_exit udp4_proc_exit_net(struct net *net)
2160 2161 2162 2163 2164 2165 2166 2167 2168
{
	udp_proc_unregister(net, &udp4_seq_afinfo);
}

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

2169 2170
int __init udp4_proc_init(void)
{
2171
	return register_pernet_subsys(&udp4_net_ops);
2172 2173 2174 2175
}

void udp4_proc_exit(void)
{
2176
	unregister_pernet_subsys(&udp4_net_ops);
2177
}
L
Linus Torvalds 已提交
2178 2179
#endif /* CONFIG_PROC_FS */

2180 2181
static __initdata unsigned long uhash_entries;
static int __init set_uhash_entries(char *str)
2182
{
2183 2184
	ssize_t ret;

2185 2186
	if (!str)
		return 0;
2187 2188 2189 2190 2191

	ret = kstrtoul(str, 0, &uhash_entries);
	if (ret)
		return 0;

2192 2193 2194 2195 2196
	if (uhash_entries && uhash_entries < UDP_HTABLE_SIZE_MIN)
		uhash_entries = UDP_HTABLE_SIZE_MIN;
	return 1;
}
__setup("uhash_entries=", set_uhash_entries);
2197

2198 2199 2200 2201
void __init udp_table_init(struct udp_table *table, const char *name)
{
	unsigned int i;

2202 2203 2204 2205 2206 2207 2208 2209 2210 2211
	table->hash = alloc_large_system_hash(name,
					      2 * sizeof(struct udp_hslot),
					      uhash_entries,
					      21, /* one slot per 2 MB */
					      0,
					      &table->log,
					      &table->mask,
					      UDP_HTABLE_SIZE_MIN,
					      64 * 1024);

2212
	table->hash2 = table->hash + (table->mask + 1);
2213
	for (i = 0; i <= table->mask; i++) {
2214
		INIT_HLIST_NULLS_HEAD(&table->hash[i].head, i);
E
Eric Dumazet 已提交
2215
		table->hash[i].count = 0;
2216 2217
		spin_lock_init(&table->hash[i].lock);
	}
2218 2219 2220 2221 2222
	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);
	}
2223 2224
}

H
Hideo Aoki 已提交
2225 2226
void __init udp_init(void)
{
2227
	unsigned long limit;
H
Hideo Aoki 已提交
2228

2229
	udp_table_init(&udp_table, "UDP");
2230
	limit = nr_free_buffer_pages() / 8;
H
Hideo Aoki 已提交
2231 2232 2233 2234 2235 2236 2237 2238 2239
	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;
}

2240 2241 2242 2243 2244 2245 2246 2247 2248 2249 2250 2251 2252 2253 2254 2255 2256 2257 2258
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;
}

2259 2260
struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
	netdev_features_t features)
2261 2262 2263 2264 2265 2266 2267 2268 2269 2270 2271 2272 2273 2274 2275 2276 2277 2278 2279 2280 2281 2282 2283 2284 2285 2286 2287
{
	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.
	 */
2288
	offset = skb_checksum_start_offset(skb);
E
Eric Dumazet 已提交
2289
	csum = skb_checksum(skb, offset, skb->len - offset, 0);
2290 2291 2292 2293 2294 2295 2296 2297 2298 2299 2300 2301
	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;
}