udp.c 48.9 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 <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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int sysctl_udp_mem[3] __read_mostly;
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);

atomic_t udp_memory_allocated;
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 || sk2->sk_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(sk2->sk_hash >> log, bitmap);
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			else
				return 1;
		}
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	return 0;
}

/**
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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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 */
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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))
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{
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	struct udp_hslot *hslot;
	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);
		for (last = first + udptable->mask + 1;
		     first != last;
		     first++) {
			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))
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					goto found;
				snum += rand;
			} while (snum != first);
			spin_unlock_bh(&hslot->lock);
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		}
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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 (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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	sk->sk_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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	}
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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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int udp_v4_get_port(struct sock *sk, unsigned short snum)
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{
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	return udp_lib_get_port(sk, snum, ipv4_rcv_saddr_equal);
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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;

	if (net_eq(sock_net(sk), net) && sk->sk_hash == hnum &&
			!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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/* 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)
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{
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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 hash = udp_hashfn(net, hnum, udptable->mask);
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	struct udp_hslot *hslot = &udptable->hash[hash];
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	int score, badness;
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	rcu_read_lock();
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.
	 */
	if (get_nulls_value(node) != hash)
		goto begin;

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	if (result) {
		if (unlikely(!atomic_inc_not_zero(&result->sk_refcnt)))
			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;
}

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static inline struct sock *__udp4_lib_lookup_skb(struct sk_buff *skb,
						 __be16 sport, __be16 dport,
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						 struct udp_table *udptable)
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{
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	struct sock *sk;
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	const struct iphdr *iph = ip_hdr(skb);

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	if (unlikely(sk = skb_steal_sock(skb)))
		return sk;
	else
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		return __udp4_lib_lookup(dev_net(skb_dst(skb)->dev), iph->saddr, sport,
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					 iph->daddr, dport, inet_iif(skb),
					 udptable);
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}

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struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
			     __be32 daddr, __be16 dport, int dif)
{
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	return __udp4_lib_lookup(net, saddr, sport, daddr, dport, dif, &udp_table);
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}
EXPORT_SYMBOL_GPL(udp4_lib_lookup);

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static inline struct sock *udp_v4_mcast_next(struct net *net, struct sock *sk,
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					     __be16 loc_port, __be32 loc_addr,
					     __be16 rmt_port, __be32 rmt_addr,
					     int dif)
{
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	struct hlist_nulls_node *node;
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	struct sock *s = sk;
	unsigned short hnum = ntohs(loc_port);

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

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		if (!net_eq(sock_net(s), net)				||
		    s->sk_hash != hnum					||
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		    (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)			||
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		    ipv6_only_sock(s)					||
		    (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.
 */

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void __udp4_lib_err(struct sk_buff *skb, u32 info, struct udp_table *udptable)
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{
	struct inet_sock *inet;
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	struct iphdr *iph = (struct iphdr *)skb->data;
	struct udphdr *uh = (struct udphdr *)(skb->data+(iph->ihl<<2));
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	const int type = icmp_hdr(skb)->type;
	const int code = icmp_hdr(skb)->code;
	struct sock *sk;
	int harderr;
	int err;
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	struct net *net = dev_net(skb->dev);
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	sk = __udp4_lib_lookup(net, iph->daddr, uh->dest,
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			iph->saddr, uh->source, skb->dev->ifindex, udptable);
	if (sk == NULL) {
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		ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
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		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;
	} else {
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		ip_icmp_error(sk, skb, err, uh->dest, info, (u8 *)(uh+1));
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	}
	sk->sk_err = err;
	sk->sk_error_report(sk);
out:
	sock_put(sk);
}

void udp_err(struct sk_buff *skb, u32 info)
{
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	__udp4_lib_err(skb, info, &udp_table);
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}

/*
 * Throw away all pending data and cancel the corking. Socket is locked.
 */
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void udp_flush_pending_frames(struct sock *sk)
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{
	struct udp_sock *up = udp_sk(sk);

	if (up->pending) {
		up->len = 0;
		up->pending = 0;
		ip_flush_pending_frames(sk);
	}
}
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EXPORT_SYMBOL(udp_flush_pending_frames);
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/**
 * 	udp4_hwcsum_outgoing  -  handle outgoing HW checksumming
 * 	@sk: 	socket we are sending on
 * 	@skb: 	sk_buff containing the filled-in UDP header
 * 	        (checksum field must be zeroed out)
 */
static void udp4_hwcsum_outgoing(struct sock *sk, struct sk_buff *skb,
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				 __be32 src, __be32 dst, int len)
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{
	unsigned int offset;
	struct udphdr *uh = udp_hdr(skb);
	__wsum csum = 0;

	if (skb_queue_len(&sk->sk_write_queue) == 1) {
		/*
		 * Only one fragment on the socket.
		 */
		skb->csum_start = skb_transport_header(skb) - skb->head;
		skb->csum_offset = offsetof(struct udphdr, check);
		uh->check = ~csum_tcpudp_magic(src, dst, len, IPPROTO_UDP, 0);
	} 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
		 */
		offset = skb_transport_offset(skb);
		skb->csum = skb_checksum(skb, offset, skb->len - offset, 0);

		skb->ip_summed = CHECKSUM_NONE;

		skb_queue_walk(&sk->sk_write_queue, skb) {
			csum = csum_add(csum, skb->csum);
		}

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

/*
 * 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;
	struct udphdr *uh;
	int err = 0;
	int is_udplite = IS_UDPLITE(sk);
	__wsum csum = 0;

	/* Grab the skbuff where UDP header space exists. */
	if ((skb = skb_peek(&sk->sk_write_queue)) == NULL)
		goto out;

	/*
	 * Create a UDP header
	 */
	uh = udp_hdr(skb);
	uh->source = fl->fl_ip_sport;
	uh->dest = fl->fl_ip_dport;
	uh->len = htons(up->len);
	uh->check = 0;

	if (is_udplite)  				 /*     UDP-Lite      */
		csum  = udplite_csum_outgoing(sk, skb);

	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 */

E
Eric Dumazet 已提交
556
		udp4_hwcsum_outgoing(sk, skb, fl->fl4_src, fl->fl4_dst, up->len);
557 558 559 560 561 562 563
		goto send;

	} else						 /*   `normal' UDP    */
		csum = udp_csum_outgoing(sk, skb);

	/* add protocol-dependent pseudo-header */
	uh->check = csum_tcpudp_magic(fl->fl4_src, fl->fl4_dst, up->len,
E
Eric Dumazet 已提交
564
				      sk->sk_protocol, csum);
565 566 567 568 569
	if (uh->check == 0)
		uh->check = CSUM_MANGLED_0;

send:
	err = ip_push_pending_frames(sk);
E
Eric Dumazet 已提交
570 571 572 573 574 575 576 577 578
	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);
579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608
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 *);

	if (len > 0xFFFF)
		return -EMSGSIZE;

	/*
	 *	Check the flags.
	 */

E
Eric Dumazet 已提交
609
	if (msg->msg_flags & MSG_OOB) /* Mirror BSD error message compatibility */
610 611 612
		return -EOPNOTSUPP;

	ipc.opt = NULL;
613
	ipc.shtx.flags = 0;
614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635

	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
636
		struct sockaddr_in * usin = (struct sockaddr_in *)msg->msg_name;
637 638 639 640 641 642 643 644 645 646 647 648 649 650
		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
651 652
		daddr = inet->inet_daddr;
		dport = inet->inet_dport;
653 654 655 656 657
		/* 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
658
	ipc.addr = inet->inet_saddr;
659 660

	ipc.oif = sk->sk_bound_dev_if;
661 662 663
	err = sock_tx_timestamp(msg, sk, &ipc.shtx);
	if (err)
		return err;
664
	if (msg->msg_controllen) {
665
		err = ip_cmsg_send(sock_net(sk), msg, &ipc);
666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700
		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
701
		rt = (struct rtable *)sk_dst_check(sk, 0);
702 703 704

	if (rt == NULL) {
		struct flowi fl = { .oif = ipc.oif,
705
				    .mark = sk->sk_mark,
706 707 708 709 710
				    .nl_u = { .ip4_u =
					      { .daddr = faddr,
						.saddr = saddr,
						.tos = tos } },
				    .proto = sk->sk_protocol,
711
				    .flags = inet_sk_flowi_flags(sk),
712
				    .uli_u = { .ports =
E
Eric Dumazet 已提交
713
					       { .sport = inet->inet_sport,
714
						 .dport = dport } } };
715 716
		struct net *net = sock_net(sk);

717
		security_sk_classify_flow(sk, &fl);
718
		err = ip_route_output_flow(net, &rt, &fl, sk, 1);
719 720
		if (err) {
			if (err == -ENETUNREACH)
721
				IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES);
722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756
			goto out;
		}

		err = -EACCES;
		if ((rt->rt_flags & RTCF_BROADCAST) &&
		    !sock_flag(sk, SOCK_BROADCAST))
			goto out;
		if (connected)
			sk_dst_set(sk, dst_clone(&rt->u.dst));
	}

	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;

	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;
	inet->cork.fl.fl_ip_dport = dport;
	inet->cork.fl.fl4_src = saddr;
E
Eric Dumazet 已提交
757
	inet->cork.fl.fl_ip_sport = inet->inet_sport;
758 759 760 761 762 763
	up->pending = AF_INET;

do_append_data:
	up->len += ulen;
	getfrag  =  is_udplite ?  udplite_getfrag : ip_generic_getfrag;
	err = ip_append_data(sk, getfrag, msg->msg_iov, ulen,
764
			sizeof(struct udphdr), &ipc, &rt,
765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787
			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)) {
788 789
		UDP_INC_STATS_USER(sock_net(sk),
				UDP_MIB_SNDBUFERRORS, is_udplite);
790 791 792 793 794 795 796 797 798 799
	}
	return err;

do_confirm:
	dst_confirm(&rt->u.dst);
	if (!(msg->msg_flags&MSG_PROBE) || len)
		goto back_from_confirm;
	err = 0;
	goto out;
}
E
Eric Dumazet 已提交
800
EXPORT_SYMBOL(udp_sendmsg);
801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849

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
850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870

/**
 *	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
871
		atomic_inc(&sk->sk_drops);
E
Eric Dumazet 已提交
872 873 874 875 876 877 878 879 880 881 882 883 884 885 886
		__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)) {
		lock_sock(sk);
		__skb_queue_purge(&list_kill);
		sk_mem_reclaim_partial(sk);
		release_sock(sk);
	}
	return res;
}

L
Linus Torvalds 已提交
887 888 889
/*
 *	IOCTL requests applicable to the UDP protocol
 */
890

L
Linus Torvalds 已提交
891 892
int udp_ioctl(struct sock *sk, int cmd, unsigned long arg)
{
893 894
	switch (cmd) {
	case SIOCOUTQ:
L
Linus Torvalds 已提交
895
	{
896 897
		int amount = sk_wmem_alloc_get(sk);

898 899
		return put_user(amount, (int __user *)arg);
	}
L
Linus Torvalds 已提交
900

901 902
	case SIOCINQ:
	{
E
Eric Dumazet 已提交
903
		unsigned int amount = first_packet_length(sk);
904

E
Eric Dumazet 已提交
905
		if (amount)
906 907 908 909 910
			/*
			 * We will only return the amount
			 * of this packet since that is all
			 * that will be read.
			 */
E
Eric Dumazet 已提交
911 912
			amount -= sizeof(struct udphdr);

913 914
		return put_user(amount, (int __user *)arg);
	}
L
Linus Torvalds 已提交
915

916 917
	default:
		return -ENOIOCTLCMD;
L
Linus Torvalds 已提交
918
	}
919 920

	return 0;
L
Linus Torvalds 已提交
921
}
E
Eric Dumazet 已提交
922
EXPORT_SYMBOL(udp_ioctl);
L
Linus Torvalds 已提交
923

924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943
/*
 * 	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;
	unsigned int ulen, copied;
	int peeked;
	int err;
	int is_udplite = IS_UDPLITE(sk);

	/*
	 *	Check any passed addresses
	 */
	if (addr_len)
E
Eric Dumazet 已提交
944
		*addr_len = sizeof(*sin);
945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974

	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);
	copied = len;
	if (copied > ulen)
		copied = ulen;
	else if (copied < ulen)
		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.
	 */

	if (copied < ulen || UDP_SKB_CB(skb)->partial_cov) {
		if (udp_lib_checksum_complete(skb))
			goto csum_copy_err;
	}

	if (skb_csum_unnecessary(skb))
		err = skb_copy_datagram_iovec(skb, sizeof(struct udphdr),
E
Eric Dumazet 已提交
975
					      msg->msg_iov, copied);
976
	else {
E
Eric Dumazet 已提交
977 978 979
		err = skb_copy_and_csum_datagram_iovec(skb,
						       sizeof(struct udphdr),
						       msg->msg_iov);
980 981 982 983 984 985 986 987 988

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

	if (err)
		goto out_free;

	if (!peeked)
989 990
		UDP_INC_STATS_USER(sock_net(sk),
				UDP_MIB_INDATAGRAMS, is_udplite);
991

992
	sock_recv_ts_and_drops(msg, sk, skb);
993 994

	/* Copy the address. */
E
Eric Dumazet 已提交
995
	if (sin) {
996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008
		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);

	err = copied;
	if (flags & MSG_TRUNC)
		err = ulen;

out_free:
1009
	skb_free_datagram_locked(sk, skb);
1010 1011 1012 1013 1014 1015
out:
	return err;

csum_copy_err:
	lock_sock(sk);
	if (!skb_kill_datagram(sk, skb, flags))
1016
		UDP_INC_STATS_USER(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
1017 1018 1019 1020 1021 1022 1023 1024
	release_sock(sk);

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


L
Linus Torvalds 已提交
1025 1026 1027 1028 1029 1030
int udp_disconnect(struct sock *sk, int flags)
{
	struct inet_sock *inet = inet_sk(sk);
	/*
	 *	1003.1g - break association.
	 */
1031

L
Linus Torvalds 已提交
1032
	sk->sk_state = TCP_CLOSE;
E
Eric Dumazet 已提交
1033 1034
	inet->inet_daddr = 0;
	inet->inet_dport = 0;
L
Linus Torvalds 已提交
1035 1036 1037 1038 1039 1040
	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
1041
		inet->inet_sport = 0;
L
Linus Torvalds 已提交
1042 1043 1044 1045
	}
	sk_dst_reset(sk);
	return 0;
}
E
Eric Dumazet 已提交
1046
EXPORT_SYMBOL(udp_disconnect);
L
Linus Torvalds 已提交
1047

1048 1049
void udp_lib_unhash(struct sock *sk)
{
1050 1051
	if (sk_hashed(sk)) {
		struct udp_table *udptable = sk->sk_prot->h.udp_table;
1052 1053
		struct udp_hslot *hslot = udp_hashslot(udptable, sock_net(sk),
						     sk->sk_hash);
1054

1055 1056
		spin_lock_bh(&hslot->lock);
		if (sk_nulls_del_node_init_rcu(sk)) {
E
Eric Dumazet 已提交
1057
			hslot->count--;
E
Eric Dumazet 已提交
1058
			inet_sk(sk)->inet_num = 0;
1059 1060 1061
			sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
		}
		spin_unlock_bh(&hslot->lock);
1062 1063 1064 1065
	}
}
EXPORT_SYMBOL(udp_lib_unhash);

H
Herbert Xu 已提交
1066 1067
static int __udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
{
E
Eric Dumazet 已提交
1068 1069 1070 1071
	int rc = sock_queue_rcv_skb(sk, skb);

	if (rc < 0) {
		int is_udplite = IS_UDPLITE(sk);
H
Herbert Xu 已提交
1072 1073

		/* Note that an ENOMEM error is charged twice */
E
Eric Dumazet 已提交
1074
		if (rc == -ENOMEM)
H
Herbert Xu 已提交
1075 1076
			UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_RCVBUFERRORS,
					 is_udplite);
E
Eric Dumazet 已提交
1077 1078 1079
		UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
		kfree_skb(skb);
		return -1;
H
Herbert Xu 已提交
1080 1081 1082 1083 1084 1085
	}

	return 0;

}

1086 1087 1088 1089 1090 1091 1092 1093
/* 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
1094
int udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125
{
	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) {
1126 1127
				UDP_INC_STATS_BH(sock_net(sk),
						 UDP_MIB_INDATAGRAMS,
1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176
						 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;
		}
	}

	if (sk->sk_filter) {
		if (udp_lib_checksum_complete(skb))
			goto drop;
	}

H
Herbert Xu 已提交
1177
	rc = 0;
1178

H
Herbert Xu 已提交
1179 1180 1181 1182 1183 1184 1185 1186
	bh_lock_sock(sk);
	if (!sock_owned_by_user(sk))
		rc = __udp_queue_rcv_skb(sk, skb);
	else
		sk_add_backlog(sk, skb);
	bh_unlock_sock(sk);

	return rc;
1187 1188

drop:
1189
	UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
E
Eric Dumazet 已提交
1190
	atomic_inc(&sk->sk_drops);
1191 1192 1193 1194 1195 1196 1197 1198 1199 1200
	kfree_skb(skb);
	return -1;
}

/*
 *	Multicasts and broadcasts go to each listener.
 *
 *	Note: called only from the BH handler context,
 *	so we don't need to lock the hashes.
 */
1201
static int __udp4_lib_mcast_deliver(struct net *net, struct sk_buff *skb,
1202 1203
				    struct udphdr  *uh,
				    __be32 saddr, __be32 daddr,
1204
				    struct udp_table *udptable)
1205 1206
{
	struct sock *sk;
1207
	struct udp_hslot *hslot = udp_hashslot(udptable, net, ntohs(uh->dest));
1208 1209
	int dif;

1210
	spin_lock(&hslot->lock);
1211
	sk = sk_nulls_head(&hslot->head);
1212
	dif = skb->dev->ifindex;
1213
	sk = udp_v4_mcast_next(net, sk, uh->dest, daddr, uh->source, saddr, dif);
1214 1215 1216 1217 1218 1219
	if (sk) {
		struct sock *sknext = NULL;

		do {
			struct sk_buff *skb1 = skb;

1220
			sknext = udp_v4_mcast_next(net, sk_nulls_next(sk), uh->dest,
1221 1222
						   daddr, uh->source, saddr,
						   dif);
1223 1224 1225 1226
			if (sknext)
				skb1 = skb_clone(skb, GFP_ATOMIC);

			if (skb1) {
H
Herbert Xu 已提交
1227
				int ret = udp_queue_rcv_skb(sk, skb1);
1228 1229 1230 1231 1232 1233 1234 1235
				if (ret > 0)
					/* we should probably re-process instead
					 * of dropping packets here. */
					kfree_skb(skb1);
			}
			sk = sknext;
		} while (sknext);
	} else
1236
		consume_skb(skb);
1237
	spin_unlock(&hslot->lock);
1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264
	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
1265
		if (!csum_tcpudp_magic(iph->saddr, iph->daddr, skb->len,
1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282
				      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.
 */

1283
int __udp4_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
1284 1285 1286
		   int proto)
{
	struct sock *sk;
1287
	struct udphdr *uh;
1288
	unsigned short ulen;
E
Eric Dumazet 已提交
1289
	struct rtable *rt = skb_rtable(skb);
1290
	__be32 saddr, daddr;
1291
	struct net *net = dev_net(skb->dev);
1292 1293 1294 1295 1296 1297 1298

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

1299
	uh   = udp_hdr(skb);
1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313
	ulen = ntohs(uh->len);
	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;

1314 1315 1316
	saddr = ip_hdr(skb)->saddr;
	daddr = ip_hdr(skb)->daddr;

1317
	if (rt->rt_flags & (RTCF_BROADCAST|RTCF_MULTICAST))
1318 1319
		return __udp4_lib_mcast_deliver(net, skb, uh,
				saddr, daddr, udptable);
1320

1321
	sk = __udp4_lib_lookup_skb(skb, uh->source, uh->dest, udptable);
1322 1323

	if (sk != NULL) {
H
Herbert Xu 已提交
1324
		int ret = udp_queue_rcv_skb(sk, skb);
1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342
		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;

1343
	UDP_INC_STATS_BH(net, UDP_MIB_NOPORTS, proto == IPPROTO_UDPLITE);
1344 1345 1346 1347 1348 1349 1350 1351 1352 1353
	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:
1354
	LIMIT_NETDEBUG(KERN_DEBUG "UDP%s: short packet: From %pI4:%u %d/%d to %pI4:%u\n",
1355
		       proto == IPPROTO_UDPLITE ? "-Lite" : "",
1356
		       &saddr,
1357 1358 1359
		       ntohs(uh->source),
		       ulen,
		       skb->len,
1360
		       &daddr,
1361 1362 1363 1364 1365 1366 1367 1368
		       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).
	 */
1369
	LIMIT_NETDEBUG(KERN_DEBUG "UDP%s: bad checksum. From %pI4:%u to %pI4:%u ulen %d\n",
1370
		       proto == IPPROTO_UDPLITE ? "-Lite" : "",
1371
		       &saddr,
1372
		       ntohs(uh->source),
1373
		       &daddr,
1374 1375 1376
		       ntohs(uh->dest),
		       ulen);
drop:
1377
	UDP_INC_STATS_BH(net, UDP_MIB_INERRORS, proto == IPPROTO_UDPLITE);
1378 1379 1380 1381 1382 1383
	kfree_skb(skb);
	return 0;
}

int udp_rcv(struct sk_buff *skb)
{
1384
	return __udp4_lib_rcv(skb, &udp_table, IPPROTO_UDP);
1385 1386
}

1387
void udp_destroy_sock(struct sock *sk)
1388 1389 1390 1391 1392 1393
{
	lock_sock(sk);
	udp_flush_pending_frames(sk);
	release_sock(sk);
}

L
Linus Torvalds 已提交
1394 1395 1396
/*
 *	Socket option code for UDP
 */
1397
int udp_lib_setsockopt(struct sock *sk, int level, int optname,
1398
		       char __user *optval, unsigned int optlen,
1399
		       int (*push_pending_frames)(struct sock *))
L
Linus Torvalds 已提交
1400 1401 1402 1403
{
	struct udp_sock *up = udp_sk(sk);
	int val;
	int err = 0;
W
Wang Chen 已提交
1404
	int is_udplite = IS_UDPLITE(sk);
L
Linus Torvalds 已提交
1405

E
Eric Dumazet 已提交
1406
	if (optlen < sizeof(int))
L
Linus Torvalds 已提交
1407 1408 1409 1410 1411
		return -EINVAL;

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

1412
	switch (optname) {
L
Linus Torvalds 已提交
1413 1414 1415 1416 1417 1418
	case UDP_CORK:
		if (val != 0) {
			up->corkflag = 1;
		} else {
			up->corkflag = 0;
			lock_sock(sk);
1419
			(*push_pending_frames)(sk);
L
Linus Torvalds 已提交
1420 1421 1422
			release_sock(sk);
		}
		break;
1423

L
Linus Torvalds 已提交
1424 1425 1426 1427 1428
	case UDP_ENCAP:
		switch (val) {
		case 0:
		case UDP_ENCAP_ESPINUDP:
		case UDP_ENCAP_ESPINUDP_NON_IKE:
1429 1430
			up->encap_rcv = xfrm4_udp_encap_rcv;
			/* FALLTHROUGH */
1431
		case UDP_ENCAP_L2TPINUDP:
L
Linus Torvalds 已提交
1432 1433 1434 1435 1436 1437 1438 1439
			up->encap_type = val;
			break;
		default:
			err = -ENOPROTOOPT;
			break;
		}
		break;

1440 1441 1442 1443 1444 1445
	/*
	 * 	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
1446
		if (!is_udplite)         /* Disable the option on UDP sockets */
1447 1448 1449
			return -ENOPROTOOPT;
		if (val != 0 && val < 8) /* Illegal coverage: use default (8) */
			val = 8;
1450 1451
		else if (val > USHORT_MAX)
			val = USHORT_MAX;
1452 1453 1454 1455
		up->pcslen = val;
		up->pcflag |= UDPLITE_SEND_CC;
		break;

1456 1457
	/* 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
1458 1459
	 * used, this again means full checksum coverage.                     */
	case UDPLITE_RECV_CSCOV:
W
Wang Chen 已提交
1460
		if (!is_udplite)         /* Disable the option on UDP sockets */
1461 1462 1463
			return -ENOPROTOOPT;
		if (val != 0 && val < 8) /* Avoid silly minimal values.       */
			val = 8;
1464 1465
		else if (val > USHORT_MAX)
			val = USHORT_MAX;
1466 1467 1468 1469
		up->pcrlen = val;
		up->pcflag |= UDPLITE_RECV_CC;
		break;

L
Linus Torvalds 已提交
1470 1471 1472
	default:
		err = -ENOPROTOOPT;
		break;
1473
	}
L
Linus Torvalds 已提交
1474 1475 1476

	return err;
}
E
Eric Dumazet 已提交
1477
EXPORT_SYMBOL(udp_lib_setsockopt);
L
Linus Torvalds 已提交
1478

1479
int udp_setsockopt(struct sock *sk, int level, int optname,
1480
		   char __user *optval, unsigned int optlen)
1481 1482 1483 1484 1485 1486 1487 1488 1489
{
	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,
1490
			  char __user *optval, unsigned int optlen)
1491 1492 1493 1494 1495 1496 1497 1498
{
	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

1499 1500
int udp_lib_getsockopt(struct sock *sk, int level, int optname,
		       char __user *optval, int __user *optlen)
L
Linus Torvalds 已提交
1501 1502 1503 1504
{
	struct udp_sock *up = udp_sk(sk);
	int val, len;

E
Eric Dumazet 已提交
1505
	if (get_user(len, optlen))
L
Linus Torvalds 已提交
1506 1507 1508
		return -EFAULT;

	len = min_t(unsigned int, len, sizeof(int));
1509

1510
	if (len < 0)
L
Linus Torvalds 已提交
1511 1512
		return -EINVAL;

1513
	switch (optname) {
L
Linus Torvalds 已提交
1514 1515 1516 1517 1518 1519 1520 1521
	case UDP_CORK:
		val = up->corkflag;
		break;

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

1522 1523 1524 1525 1526 1527 1528 1529 1530 1531
	/* 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
1532 1533
	default:
		return -ENOPROTOOPT;
1534
	}
L
Linus Torvalds 已提交
1535

1536
	if (put_user(len, optlen))
1537
		return -EFAULT;
E
Eric Dumazet 已提交
1538
	if (copy_to_user(optval, &val, len))
L
Linus Torvalds 已提交
1539
		return -EFAULT;
1540
	return 0;
L
Linus Torvalds 已提交
1541
}
E
Eric Dumazet 已提交
1542
EXPORT_SYMBOL(udp_lib_getsockopt);
L
Linus Torvalds 已提交
1543

1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560
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
1561 1562 1563 1564 1565 1566
/**
 * 	udp_poll - wait for a UDP event.
 *	@file - file struct
 *	@sock - socket
 *	@wait - poll table
 *
1567
 *	This is same as datagram poll, except for the special case of
L
Linus Torvalds 已提交
1568 1569 1570 1571 1572 1573 1574 1575 1576 1577
 *	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;
1578

L
Linus Torvalds 已提交
1579
	/* Check for false positives due to checksum errors */
E
Eric Dumazet 已提交
1580 1581 1582
	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
1583 1584

	return mask;
1585

L
Linus Torvalds 已提交
1586
}
E
Eric Dumazet 已提交
1587
EXPORT_SYMBOL(udp_poll);
L
Linus Torvalds 已提交
1588

1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601
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
1602
	.backlog_rcv	   = __udp_queue_rcv_skb,
1603 1604 1605 1606 1607 1608 1609 1610
	.hash		   = udp_lib_hash,
	.unhash		   = udp_lib_unhash,
	.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),
1611
	.slab_flags	   = SLAB_DESTROY_BY_RCU,
1612
	.h.udp_table	   = &udp_table,
1613 1614 1615 1616 1617
#ifdef CONFIG_COMPAT
	.compat_setsockopt = compat_udp_setsockopt,
	.compat_getsockopt = compat_udp_getsockopt,
#endif
};
E
Eric Dumazet 已提交
1618
EXPORT_SYMBOL(udp_prot);
L
Linus Torvalds 已提交
1619 1620 1621 1622

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

1623
static struct sock *udp_get_first(struct seq_file *seq, int start)
L
Linus Torvalds 已提交
1624 1625 1626
{
	struct sock *sk;
	struct udp_iter_state *state = seq->private;
1627
	struct net *net = seq_file_net(seq);
L
Linus Torvalds 已提交
1628

1629 1630
	for (state->bucket = start; state->bucket <= state->udp_table->mask;
	     ++state->bucket) {
1631
		struct hlist_nulls_node *node;
1632
		struct udp_hslot *hslot = &state->udp_table->hash[state->bucket];
1633 1634 1635 1636

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

1637
		spin_lock_bh(&hslot->lock);
1638
		sk_nulls_for_each(sk, node, &hslot->head) {
1639
			if (!net_eq(sock_net(sk), net))
1640
				continue;
L
Linus Torvalds 已提交
1641 1642 1643
			if (sk->sk_family == state->family)
				goto found;
		}
1644
		spin_unlock_bh(&hslot->lock);
L
Linus Torvalds 已提交
1645 1646 1647 1648 1649 1650 1651 1652 1653
	}
	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;
1654
	struct net *net = seq_file_net(seq);
L
Linus Torvalds 已提交
1655 1656

	do {
1657
		sk = sk_nulls_next(sk);
1658
	} while (sk && (!net_eq(sock_net(sk), net) || sk->sk_family != state->family));
L
Linus Torvalds 已提交
1659

1660
	if (!sk) {
1661
		if (state->bucket <= state->udp_table->mask)
1662
			spin_unlock_bh(&state->udp_table->hash[state->bucket].lock);
1663
		return udp_get_first(seq, state->bucket + 1);
L
Linus Torvalds 已提交
1664 1665 1666 1667 1668 1669
	}
	return sk;
}

static struct sock *udp_get_idx(struct seq_file *seq, loff_t pos)
{
1670
	struct sock *sk = udp_get_first(seq, 0);
L
Linus Torvalds 已提交
1671 1672

	if (sk)
1673
		while (pos && (sk = udp_get_next(seq, sk)) != NULL)
L
Linus Torvalds 已提交
1674 1675 1676 1677 1678 1679
			--pos;
	return pos ? NULL : sk;
}

static void *udp_seq_start(struct seq_file *seq, loff_t *pos)
{
1680
	struct udp_iter_state *state = seq->private;
1681
	state->bucket = MAX_UDP_PORTS;
1682

1683
	return *pos ? udp_get_idx(seq, *pos-1) : SEQ_START_TOKEN;
L
Linus Torvalds 已提交
1684 1685 1686 1687 1688 1689
}

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

1690
	if (v == SEQ_START_TOKEN)
L
Linus Torvalds 已提交
1691 1692 1693 1694 1695 1696 1697 1698 1699 1700
		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)
{
1701 1702
	struct udp_iter_state *state = seq->private;

1703
	if (state->bucket <= state->udp_table->mask)
1704
		spin_unlock_bh(&state->udp_table->hash[state->bucket].lock);
L
Linus Torvalds 已提交
1705 1706 1707 1708 1709
}

static int udp_seq_open(struct inode *inode, struct file *file)
{
	struct udp_seq_afinfo *afinfo = PDE(inode)->data;
1710 1711
	struct udp_iter_state *s;
	int err;
1712

1713 1714 1715 1716
	err = seq_open_net(inode, file, &afinfo->seq_ops,
			   sizeof(struct udp_iter_state));
	if (err < 0)
		return err;
1717

1718
	s = ((struct seq_file *)file->private_data)->private;
L
Linus Torvalds 已提交
1719
	s->family		= afinfo->family;
1720
	s->udp_table		= afinfo->udp_table;
1721
	return err;
1722 1723
}

L
Linus Torvalds 已提交
1724
/* ------------------------------------------------------------------------ */
1725
int udp_proc_register(struct net *net, struct udp_seq_afinfo *afinfo)
L
Linus Torvalds 已提交
1726 1727 1728 1729
{
	struct proc_dir_entry *p;
	int rc = 0;

1730 1731 1732 1733
	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
1734

1735 1736 1737 1738
	afinfo->seq_ops.start		= udp_seq_start;
	afinfo->seq_ops.next		= udp_seq_next;
	afinfo->seq_ops.stop		= udp_seq_stop;

1739 1740 1741
	p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
			     &afinfo->seq_fops, afinfo);
	if (!p)
L
Linus Torvalds 已提交
1742 1743 1744
		rc = -ENOMEM;
	return rc;
}
E
Eric Dumazet 已提交
1745
EXPORT_SYMBOL(udp_proc_register);
L
Linus Torvalds 已提交
1746

1747
void udp_proc_unregister(struct net *net, struct udp_seq_afinfo *afinfo)
L
Linus Torvalds 已提交
1748
{
1749
	proc_net_remove(net, afinfo->name);
L
Linus Torvalds 已提交
1750
}
E
Eric Dumazet 已提交
1751
EXPORT_SYMBOL(udp_proc_unregister);
1752 1753

/* ------------------------------------------------------------------------ */
1754 1755
static void udp4_format_sock(struct sock *sp, struct seq_file *f,
		int bucket, int *len)
1756 1757
{
	struct inet_sock *inet = inet_sk(sp);
E
Eric Dumazet 已提交
1758 1759 1760 1761
	__be32 dest = inet->inet_daddr;
	__be32 src  = inet->inet_rcv_saddr;
	__u16 destp	  = ntohs(inet->inet_dport);
	__u16 srcp	  = ntohs(inet->inet_sport);
1762

1763
	seq_printf(f, "%5d: %08X:%04X %08X:%04X"
E
Eric Dumazet 已提交
1764
		" %02X %08X:%08X %02X:%08lX %08X %5d %8d %lu %d %p %d%n",
1765
		bucket, src, srcp, dest, destp, sp->sk_state,
1766 1767
		sk_wmem_alloc_get(sp),
		sk_rmem_alloc_get(sp),
1768
		0, 0L, 0, sock_i_uid(sp), 0, sock_i_ino(sp),
E
Eric Dumazet 已提交
1769 1770
		atomic_read(&sp->sk_refcnt), sp,
		atomic_read(&sp->sk_drops), len);
1771 1772 1773 1774 1775 1776 1777 1778
}

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
1779
			   "inode ref pointer drops");
1780 1781
	else {
		struct udp_iter_state *state = seq->private;
1782
		int len;
1783

1784
		udp4_format_sock(v, seq, state->bucket, &len);
E
Eric Dumazet 已提交
1785
		seq_printf(seq, "%*s\n", 127 - len, "");
1786 1787 1788 1789 1790 1791 1792 1793
	}
	return 0;
}

/* ------------------------------------------------------------------------ */
static struct udp_seq_afinfo udp4_seq_afinfo = {
	.name		= "udp",
	.family		= AF_INET,
1794
	.udp_table	= &udp_table,
1795 1796 1797
	.seq_fops	= {
		.owner	=	THIS_MODULE,
	},
1798 1799 1800
	.seq_ops	= {
		.show		= udp4_seq_show,
	},
1801 1802
};

1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817
static int udp4_proc_init_net(struct net *net)
{
	return udp_proc_register(net, &udp4_seq_afinfo);
}

static void udp4_proc_exit_net(struct net *net)
{
	udp_proc_unregister(net, &udp4_seq_afinfo);
}

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

1818 1819
int __init udp4_proc_init(void)
{
1820
	return register_pernet_subsys(&udp4_net_ops);
1821 1822 1823 1824
}

void udp4_proc_exit(void)
{
1825
	unregister_pernet_subsys(&udp4_net_ops);
1826
}
L
Linus Torvalds 已提交
1827 1828
#endif /* CONFIG_PROC_FS */

1829 1830
static __initdata unsigned long uhash_entries;
static int __init set_uhash_entries(char *str)
1831
{
1832 1833 1834 1835 1836 1837 1838 1839
	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);
1840

1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865
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,
			sizeof(struct udp_hslot),
			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 *
				      sizeof(struct udp_hslot), GFP_KERNEL);
		if (!table->hash)
			panic(name);
		table->log = ilog2(UDP_HTABLE_SIZE_MIN);
		table->mask = UDP_HTABLE_SIZE_MIN - 1;
	}
	for (i = 0; i <= table->mask; i++) {
1866
		INIT_HLIST_NULLS_HEAD(&table->hash[i].head, i);
E
Eric Dumazet 已提交
1867
		table->hash[i].count = 0;
1868 1869 1870 1871
		spin_lock_init(&table->hash[i].lock);
	}
}

H
Hideo Aoki 已提交
1872 1873
void __init udp_init(void)
{
1874
	unsigned long nr_pages, limit;
H
Hideo Aoki 已提交
1875

1876
	udp_table_init(&udp_table, "UDP");
H
Hideo Aoki 已提交
1877 1878 1879 1880
	/* 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.
	 */
1881 1882 1883
	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
1884 1885 1886 1887 1888 1889 1890 1891 1892
	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;
}

1893 1894 1895 1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940
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;
}

struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb, int features)
{
	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.
	 */
	offset = skb->csum_start - skb_headroom(skb);
E
Eric Dumazet 已提交
1941
	csum = skb_checksum(skb, offset, skb->len - offset, 0);
1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953
	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;
}