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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).
*
* Authors: Ross Biro
* Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
* Arnt Gulbrandsen, <agulbra@nvg.unit.no>
* Alan Cox, <alan@lxorguk.ukuu.org.uk>
* 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
* Alan Cox : Tidied select() semantics.
* Alan Cox : udp_err() fixed properly, also now
* 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
* for connect.
* 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
* James Chapman : Add L2TP encapsulation type.
*
*
* 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.
*/

#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/ioctls.h>
#include <linux/bootmem.h>
#include <linux/highmem.h>
#include <linux/swap.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/module.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/igmp.h>
#include <linux/in.h>
#include <linux/errno.h>
#include <linux/timer.h>
#include <linux/mm.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/slab.h>
#include <net/tcp_states.h>
#include <linux/skbuff.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <net/net_namespace.h>
#include <net/icmp.h>
#include <net/route.h>
#include <net/checksum.h>
#include <net/xfrm.h>
#include <trace/events/udp.h>
#include "udp_impl.h"

struct udp_table udp_table __read_mostly;
EXPORT_SYMBOL(udp_table);

long sysctl_udp_mem[3] __read_mostly;
EXPORT_SYMBOL(sysctl_udp_mem);

int sysctl_udp_rmem_min __read_mostly;
EXPORT_SYMBOL(sysctl_udp_rmem_min);

int sysctl_udp_wmem_min __read_mostly;
EXPORT_SYMBOL(sysctl_udp_wmem_min);

atomic_long_t udp_memory_allocated;
EXPORT_SYMBOL(udp_memory_allocated);

#define MAX_UDP_PORTS 65536
#define PORTS_PER_CHAIN (MAX_UDP_PORTS / UDP_HTABLE_SIZE_MIN)

static int udp_lib_lport_inuse(struct net *net, __u16 num,
const struct udp_hslot *hslot,
unsigned long *bitmap,
struct sock *sk,
int (*saddr_comp)(const struct sock *sk1,
const struct sock *sk2),
unsigned int log)
{
struct sock *sk2;
struct hlist_nulls_node *node;

sk_nulls_for_each(sk2, node, &hslot->head)
if (net_eq(sock_net(sk2), net) &&
sk2 != sk &&
(bitmap || 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) &&
(*saddr_comp)(sk, sk2)) {
if (bitmap)
__set_bit(udp_sk(sk2)->udp_port_hash >> log,
bitmap);
else
return 1;
}
return 0;
}

/*
* 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)
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) &&
(*saddr_comp)(sk, sk2)) {
res = 1;
break;
}
spin_unlock(&hslot2->lock);
return res;
}

/**
* udp_lib_get_port - UDP/-Lite port lookup for IPv4 and IPv6
*
* @sk: socket struct in question
* @snum: port number to look up
* @saddr_comp: AF-dependent comparison of bound local IP addresses
* @hash2_nulladdr: AF-dependent hash value in secondary hash chains,
* with NULL address
*/
int udp_lib_get_port(struct sock *sk, unsigned short snum,
int (*saddr_comp)(const struct sock *sk1,
const struct sock *sk2),
unsigned int hash2_nulladdr)
{
struct udp_hslot *hslot, *hslot2;
struct udp_table *udptable = sk->sk_prot->h.udp_table;
int error = 1;
struct net *net = sock_net(sk);

if (!snum) {
int low, high, remaining;
unsigned rand;
unsigned short first, last;
DECLARE_BITMAP(bitmap, PORTS_PER_CHAIN);

inet_get_local_port_range(&low, &high);
remaining = (high - low) + 1;

rand = net_random();
first = (((u64)rand * remaining) >> 32) + low;
/*
* force rand to be an odd multiple of UDP_HTABLE_SIZE
*/
rand = (rand | 1) * (udptable->mask + 1);
last = first + udptable->mask + 1;
do {
hslot = udp_hashslot(udptable, net, first);
bitmap_zero(bitmap, PORTS_PER_CHAIN);
spin_lock_bh(&hslot->lock);
udp_lib_lport_inuse(net, snum, hslot, bitmap, sk,
saddr_comp, udptable->log);

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.
*/
do {
if (low <= snum && snum <= high &&
!test_bit(snum >> udptable->log, bitmap) &&
!inet_is_reserved_local_port(snum))
goto found;
snum += rand;
} while (snum != first);
spin_unlock_bh(&hslot->lock);
} while (++first != last);
goto fail;
} else {
hslot = udp_hashslot(udptable, net, snum);
spin_lock_bh(&hslot->lock);
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:
if (udp_lib_lport_inuse(net, snum, hslot, NULL, sk,
saddr_comp, 0))
goto fail_unlock;
}
found:
inet_sk(sk)->inet_num = snum;
udp_sk(sk)->udp_port_hash = snum;
udp_sk(sk)->udp_portaddr_hash ^= snum;
if (sk_unhashed(sk)) {
sk_nulls_add_node_rcu(sk, &hslot->head);
hslot->count++;
sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);

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);
}
error = 0;
fail_unlock:
spin_unlock_bh(&hslot->lock);
fail:
return error;
}
EXPORT_SYMBOL(udp_lib_get_port);

static int ipv4_rcv_saddr_equal(const struct sock *sk1, const struct sock *sk2)
{
struct inet_sock *inet1 = inet_sk(sk1), *inet2 = inet_sk(sk2);

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

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

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

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

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) && udp_sk(sk)->udp_port_hash == hnum &&
!ipv6_only_sock(sk)) {
struct inet_sock *inet = inet_sk(sk);

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

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

/* 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,
int dif, struct udp_table *udptable)
{
struct sock *sk, *result;
struct hlist_nulls_node *node;
unsigned short hnum = ntohs(dport);
unsigned int hash2, slot2, slot = udp_hashfn(net, hnum, udptable->mask);
struct udp_hslot *hslot2, *hslot = &udptable->hash[slot];
int score, badness;

rcu_read_lock();
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) {
hash2 = udp4_portaddr_hash(net, htonl(INADDR_ANY), hnum);
slot2 = hash2 & udptable->mask;
hslot2 = &udptable->hash2[slot2];
if (hslot->count < hslot2->count)
goto begin;

result = udp4_lib_lookup2(net, saddr, sport,
htonl(INADDR_ANY), hnum, dif,
hslot2, slot2);
}
rcu_read_unlock();
return result;
}
begin:
result = NULL;
badness = -1;
sk_nulls_for_each_rcu(sk, node, &hslot->head) {
score = compute_score(sk, net, saddr, hnum, sport,
daddr, dport, dif);
if (score > badness) {
result = sk;
badness = score;
}
}
/*
* 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) != slot)
goto begin;

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

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

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

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

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

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

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) ||
(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.
*/

void __udp4_lib_err(struct sk_buff *skb, u32 info, struct udp_table *udptable)
{
struct inet_sock *inet;
const struct iphdr *iph = (const struct iphdr *)skb->data;
struct udphdr *uh = (struct udphdr *)(skb->data+(iph->ihl<<2));
const int type = icmp_hdr(skb)->type;
const int code = icmp_hdr(skb)->code;
struct sock *sk;
int harderr;
int err;
struct net *net = dev_net(skb->dev);

sk = __udp4_lib_lookup(net, iph->daddr, uh->dest,
iph->saddr, uh->source, skb->dev->ifindex, udptable);
if (sk == NULL) {
ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
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
ip_icmp_error(sk, skb, err, uh->dest, info, (u8 *)(uh+1));

sk->sk_err = err;
sk->sk_error_report(sk);
out:
sock_put(sk);
}

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

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

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

/**
* udp4_hwcsum - handle outgoing HW checksumming
* @skb: sk_buff containing the filled-in UDP header
* (checksum field must be zeroed out)
* @src: source IP address
* @dst: destination IP address
*/
static void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst)
{
struct udphdr *uh = udp_hdr(skb);
struct sk_buff *frags = skb_shinfo(skb)->frag_list;
int offset = skb_transport_offset(skb);
int len = skb->len - offset;
int hlen = len;
__wsum csum = 0;

if (!frags) {
/*
* 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
*/
do {
csum = csum_add(csum, frags->csum);
hlen -= frags->len;
} while ((frags = frags->next));

csum = skb_checksum(skb, offset, hlen, csum);
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;
}
}

static int udp_send_skb(struct sk_buff *skb, struct flowi4 *fl4)
{
struct sock *sk = skb->sk;
struct inet_sock *inet = inet_sk(sk);
struct udphdr *uh;
int err = 0;
int is_udplite = IS_UDPLITE(sk);
int offset = skb_transport_offset(skb);
int len = skb->len - offset;
__wsum csum = 0;

/*
* Create a UDP header
*/
uh = udp_hdr(skb);
uh->source = inet->inet_sport;
uh->dest = fl4->fl4_dport;
uh->len = htons(len);
uh->check = 0;

if (is_udplite) /* UDP-Lite */
csum = udplite_csum(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 */

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

} else
csum = udp_csum(skb);

/* add protocol-dependent pseudo-header */
uh->check = csum_tcpudp_magic(fl4->saddr, fl4->daddr, len,
sk->sk_protocol, csum);
if (uh->check == 0)
uh->check = CSUM_MANGLED_0;

send:
err = ip_send_skb(skb);
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);
return err;
}

/*
* Push out all pending data as one UDP datagram. Socket is locked.
*/
static int udp_push_pending_frames(struct sock *sk)
{
struct udp_sock *up = udp_sk(sk);
struct inet_sock *inet = inet_sk(sk);
struct flowi4 *fl4 = &inet->cork.fl.u.ip4;
struct sk_buff *skb;
int err = 0;

skb = ip_finish_skb(sk, fl4);
if (!skb)
goto out;

err = udp_send_skb(skb, fl4);

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);
struct flowi4 fl4_stack;
struct flowi4 *fl4;
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 *);
struct sk_buff *skb;
struct ip_options_data opt_copy;

if (len > 0xFFFF)
return -EMSGSIZE;

/*
* Check the flags.
*/

if (msg->msg_flags & MSG_OOB) /* Mirror BSD error message compatibility */
return -EOPNOTSUPP;

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

getfrag = is_udplite ? udplite_getfrag : ip_generic_getfrag;

fl4 = &inet->cork.fl.u.ip4;
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) {
struct sockaddr_in * usin = (struct sockaddr_in *)msg->msg_name;
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;
daddr = inet->inet_daddr;
dport = inet->inet_dport;
/* Open fast path for connected socket.
Route will not be used, if at least one option is set.
*/
connected = 1;
}
ipc.addr = inet->inet_saddr;

ipc.oif = sk->sk_bound_dev_if;
err = sock_tx_timestamp(sk, &ipc.tx_flags);
if (err)
return err;
if (msg->msg_controllen) {
err = ip_cmsg_send(sock_net(sk), msg, &ipc);
if (err)
return err;
if (ipc.opt)
free = 1;
connected = 0;
}
if (!ipc.opt) {
struct ip_options_rcu *inet_opt;

rcu_read_lock();
inet_opt = rcu_dereference(inet->inet_opt);
if (inet_opt) {
memcpy(&opt_copy, inet_opt,
sizeof(*inet_opt) + inet_opt->opt.optlen);
ipc.opt = &opt_copy.opt;
}
rcu_read_unlock();
}

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

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

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

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

security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
rt = ip_route_output_flow(net, fl4, sk);
if (IS_ERR(rt)) {
err = PTR_ERR(rt);
rt = NULL;
if (err == -ENETUNREACH)
IP_INC_STATS_BH(net, IPSTATS_MIB_OUTNOROUTES);
goto out;
}

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

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

saddr = fl4->saddr;
if (!ipc.addr)
daddr = ipc.addr = fl4->daddr;

/* Lockless fast path for the non-corking case. */
if (!corkreq) {
skb = ip_make_skb(sk, fl4, getfrag, msg->msg_iov, ulen,
sizeof(struct udphdr), &ipc, &rt,
msg->msg_flags);
err = PTR_ERR(skb);
if (skb && !IS_ERR(skb))
err = udp_send_skb(skb, fl4);
goto out;
}

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.
*/
fl4 = &inet->cork.fl.u.ip4;
fl4->daddr = daddr;
fl4->saddr = saddr;
fl4->fl4_dport = dport;
fl4->fl4_sport = inet->inet_sport;
up->pending = AF_INET;

do_append_data:
up->len += ulen;
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);
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)) {
UDP_INC_STATS_USER(sock_net(sk),
UDP_MIB_SNDBUFERRORS, is_udplite);
}
return err;

do_confirm:
dst_confirm(&rt->dst);
if (!(msg->msg_flags&MSG_PROBE) || len)
goto back_from_confirm;
err = 0;
goto out;
}
EXPORT_SYMBOL(udp_sendmsg);

int udp_sendpage(struct sock *sk, struct page *page, int offset,
size_t size, int flags)
{
struct inet_sock *inet = inet_sk(sk);
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, &inet->cork.fl.u.ip4,
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;
}


/**
* 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));
atomic_inc(&sk->sk_drops);
__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)) {
bool slow = lock_sock_fast(sk);

__skb_queue_purge(&list_kill);
sk_mem_reclaim_partial(sk);
unlock_sock_fast(sk, slow);
}
return res;
}

/*
* IOCTL requests applicable to the UDP protocol
*/

int udp_ioctl(struct sock *sk, int cmd, unsigned long arg)
{
switch (cmd) {
case SIOCOUTQ:
{
int amount = sk_wmem_alloc_get(sk);

return put_user(amount, (int __user *)arg);
}

case SIOCINQ:
{
unsigned int amount = first_packet_length(sk);

if (amount)
/*
* We will only return the amount
* of this packet since that is all
* that will be read.
*/
amount -= sizeof(struct udphdr);

return put_user(amount, (int __user *)arg);
}

default:
return -ENOIOCTLCMD;
}

return 0;
}
EXPORT_SYMBOL(udp_ioctl);

/*
* 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);
bool slow;

/*
* Check any passed addresses
*/
if (addr_len)
*addr_len = sizeof(*sin);

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),
msg->msg_iov, copied);
else {
err = skb_copy_and_csum_datagram_iovec(skb,
sizeof(struct udphdr),
msg->msg_iov);

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

if (err)
goto out_free;

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

sock_recv_ts_and_drops(msg, sk, skb);

/* Copy the address. */
if (sin) {
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:
skb_free_datagram_locked(sk, skb);
out:
return err;

csum_copy_err:
slow = lock_sock_fast(sk);
if (!skb_kill_datagram(sk, skb, flags))
UDP_INC_STATS_USER(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
unlock_sock_fast(sk, slow);

if (noblock)
return -EAGAIN;

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


int udp_disconnect(struct sock *sk, int flags)
{
struct inet_sock *inet = inet_sk(sk);
/*
* 1003.1g - break association.
*/

sk->sk_state = TCP_CLOSE;
inet->inet_daddr = 0;
inet->inet_dport = 0;
sock_rps_reset_rxhash(sk);
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);
inet->inet_sport = 0;
}
sk_dst_reset(sk);
return 0;
}
EXPORT_SYMBOL(udp_disconnect);

void udp_lib_unhash(struct sock *sk)
{
if (sk_hashed(sk)) {
struct udp_table *udptable = sk->sk_prot->h.udp_table;
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);

spin_lock_bh(&hslot->lock);
if (sk_nulls_del_node_init_rcu(sk)) {
hslot->count--;
inet_sk(sk)->inet_num = 0;
sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);

spin_lock(&hslot2->lock);
hlist_nulls_del_init_rcu(&udp_sk(sk)->udp_portaddr_node);
hslot2->count--;
spin_unlock(&hslot2->lock);
}
spin_unlock_bh(&hslot->lock);
}
}
EXPORT_SYMBOL(udp_lib_unhash);

/*
* 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);
}

static int __udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
{
int rc;

if (inet_sk(sk)->inet_daddr)
sock_rps_save_rxhash(sk, skb);

rc = ip_queue_rcv_skb(sk, skb);
if (rc < 0) {
int is_udplite = IS_UDPLITE(sk);

/* Note that an ENOMEM error is charged twice */
if (rc == -ENOMEM)
UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_RCVBUFERRORS,
is_udplite);
UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
kfree_skb(skb);
trace_udp_fail_queue_rcv_skb(rc, sk);
return -1;
}

return 0;

}

/* 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.
*/
int udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
{
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) {
int (*encap_rcv)(struct sock *sk, struct sk_buff *skb);

/*
* 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 */
encap_rcv = ACCESS_ONCE(up->encap_rcv);
if (skb->len > sizeof(struct udphdr) && encap_rcv != NULL) {
int ret;

ret = encap_rcv(sk, skb);
if (ret <= 0) {
UDP_INC_STATS_BH(sock_net(sk),
UDP_MIB_INDATAGRAMS,
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 (rcu_access_pointer(sk->sk_filter) &&
udp_lib_checksum_complete(skb))
goto drop;


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

rc = 0;

bh_lock_sock(sk);
if (!sock_owned_by_user(sk))
rc = __udp_queue_rcv_skb(sk, skb);
else if (sk_add_backlog(sk, skb)) {
bh_unlock_sock(sk);
goto drop;
}
bh_unlock_sock(sk);

return rc;

drop:
UDP_INC_STATS_BH(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
atomic_inc(&sk->sk_drops);
kfree_skb(skb);
return -1;
}


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;
struct sock *sk;

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

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)
skb1 = NULL;
}
if (unlikely(skb1))
kfree_skb(skb1);
}

/*
* Multicasts and broadcasts go to each listener.
*
* Note: called only from the BH handler context.
*/
static int __udp4_lib_mcast_deliver(struct net *net, struct sk_buff *skb,
struct udphdr *uh,
__be32 saddr, __be32 daddr,
struct udp_table *udptable)
{
struct sock *sk, *stack[256 / sizeof(struct sock *)];
struct udp_hslot *hslot = udp_hashslot(udptable, net, ntohs(uh->dest));
int dif;
unsigned int i, count = 0;

spin_lock(&hslot->lock);
sk = sk_nulls_head(&hslot->head);
dif = skb->dev->ifindex;
sk = udp_v4_mcast_next(net, sk, uh->dest, daddr, uh->source, saddr, dif);
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]);

spin_unlock(&hslot->lock);

/*
* 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);
}
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) {
if (!csum_tcpudp_magic(iph->saddr, iph->daddr, skb->len,
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.
*/

int __udp4_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
int proto)
{
struct sock *sk;
struct udphdr *uh;
unsigned short ulen;
struct rtable *rt = skb_rtable(skb);
__be32 saddr, daddr;
struct net *net = dev_net(skb->dev);

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

uh = udp_hdr(skb);
ulen = ntohs(uh->len);
saddr = ip_hdr(skb)->saddr;
daddr = ip_hdr(skb)->daddr;

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))
return __udp4_lib_mcast_deliver(net, skb, uh,
saddr, daddr, udptable);

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

if (sk != NULL) {
int ret = udp_queue_rcv_skb(sk, skb);
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;

UDP_INC_STATS_BH(net, UDP_MIB_NOPORTS, proto == IPPROTO_UDPLITE);
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:
LIMIT_NETDEBUG(KERN_DEBUG "UDP%s: short packet: From %pI4:%u %d/%d to %pI4:%u\n",
proto == IPPROTO_UDPLITE ? "-Lite" : "",
&saddr,
ntohs(uh->source),
ulen,
skb->len,
&daddr,
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).
*/
LIMIT_NETDEBUG(KERN_DEBUG "UDP%s: bad checksum. From %pI4:%u to %pI4:%u ulen %d\n",
proto == IPPROTO_UDPLITE ? "-Lite" : "",
&saddr,
ntohs(uh->source),
&daddr,
ntohs(uh->dest),
ulen);
drop:
UDP_INC_STATS_BH(net, UDP_MIB_INERRORS, proto == IPPROTO_UDPLITE);
kfree_skb(skb);
return 0;
}

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

void udp_destroy_sock(struct sock *sk)
{
bool slow = lock_sock_fast(sk);
udp_flush_pending_frames(sk);
unlock_sock_fast(sk, slow);
}

/*
* Socket option code for UDP
*/
int udp_lib_setsockopt(struct sock *sk, int level, int optname,
char __user *optval, unsigned int optlen,
int (*push_pending_frames)(struct sock *))
{
struct udp_sock *up = udp_sk(sk);
int val;
int err = 0;
int is_udplite = IS_UDPLITE(sk);

if (optlen < sizeof(int))
return -EINVAL;

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

switch (optname) {
case UDP_CORK:
if (val != 0) {
up->corkflag = 1;
} else {
up->corkflag = 0;
lock_sock(sk);
(*push_pending_frames)(sk);
release_sock(sk);
}
break;

case UDP_ENCAP:
switch (val) {
case 0:
case UDP_ENCAP_ESPINUDP:
case UDP_ENCAP_ESPINUDP_NON_IKE:
up->encap_rcv = xfrm4_udp_encap_rcv;
/* FALLTHROUGH */
case UDP_ENCAP_L2TPINUDP:
up->encap_type = val;
break;
default:
err = -ENOPROTOOPT;
break;
}
break;

/*
* 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:
if (!is_udplite) /* Disable the option on UDP sockets */
return -ENOPROTOOPT;
if (val != 0 && val < 8) /* Illegal coverage: use default (8) */
val = 8;
else if (val > USHRT_MAX)
val = USHRT_MAX;
up->pcslen = val;
up->pcflag |= UDPLITE_SEND_CC;
break;

/* 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
* used, this again means full checksum coverage. */
case UDPLITE_RECV_CSCOV:
if (!is_udplite) /* Disable the option on UDP sockets */
return -ENOPROTOOPT;
if (val != 0 && val < 8) /* Avoid silly minimal values. */
val = 8;
else if (val > USHRT_MAX)
val = USHRT_MAX;
up->pcrlen = val;
up->pcflag |= UDPLITE_RECV_CC;
break;

default:
err = -ENOPROTOOPT;
break;
}

return err;
}
EXPORT_SYMBOL(udp_lib_setsockopt);

int udp_setsockopt(struct sock *sk, int level, int optname,
char __user *optval, unsigned int optlen)
{
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,
char __user *optval, unsigned int optlen)
{
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

int udp_lib_getsockopt(struct sock *sk, int level, int optname,
char __user *optval, int __user *optlen)
{
struct udp_sock *up = udp_sk(sk);
int val, len;

if (get_user(len, optlen))
return -EFAULT;

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

if (len < 0)
return -EINVAL;

switch (optname) {
case UDP_CORK:
val = up->corkflag;
break;

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

/* 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;

default:
return -ENOPROTOOPT;
}

if (put_user(len, optlen))
return -EFAULT;
if (copy_to_user(optval, &val, len))
return -EFAULT;
return 0;
}
EXPORT_SYMBOL(udp_lib_getsockopt);

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
/**
* udp_poll - wait for a UDP event.
* @file - file struct
* @sock - socket
* @wait - poll table
*
* This is same as datagram poll, except for the special case of
* 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;

/* Check for false positives due to checksum errors */
if ((mask & POLLRDNORM) && !(file->f_flags & O_NONBLOCK) &&
!(sk->sk_shutdown & RCV_SHUTDOWN) && !first_packet_length(sk))
mask &= ~(POLLIN | POLLRDNORM);

return mask;

}
EXPORT_SYMBOL(udp_poll);

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,
.backlog_rcv = __udp_queue_rcv_skb,
.hash = udp_lib_hash,
.unhash = udp_lib_unhash,
.rehash = udp_v4_rehash,
.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),
.slab_flags = SLAB_DESTROY_BY_RCU,
.h.udp_table = &udp_table,
#ifdef CONFIG_COMPAT
.compat_setsockopt = compat_udp_setsockopt,
.compat_getsockopt = compat_udp_getsockopt,
#endif
.clear_sk = sk_prot_clear_portaddr_nulls,
};
EXPORT_SYMBOL(udp_prot);

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

static struct sock *udp_get_first(struct seq_file *seq, int start)
{
struct sock *sk;
struct udp_iter_state *state = seq->private;
struct net *net = seq_file_net(seq);

for (state->bucket = start; state->bucket <= state->udp_table->mask;
++state->bucket) {
struct hlist_nulls_node *node;
struct udp_hslot *hslot = &state->udp_table->hash[state->bucket];

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

spin_lock_bh(&hslot->lock);
sk_nulls_for_each(sk, node, &hslot->head) {
if (!net_eq(sock_net(sk), net))
continue;
if (sk->sk_family == state->family)
goto found;
}
spin_unlock_bh(&hslot->lock);
}
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;
struct net *net = seq_file_net(seq);

do {
sk = sk_nulls_next(sk);
} while (sk && (!net_eq(sock_net(sk), net) || sk->sk_family != state->family));

if (!sk) {
if (state->bucket <= state->udp_table->mask)
spin_unlock_bh(&state->udp_table->hash[state->bucket].lock);
return udp_get_first(seq, state->bucket + 1);
}
return sk;
}

static struct sock *udp_get_idx(struct seq_file *seq, loff_t pos)
{
struct sock *sk = udp_get_first(seq, 0);

if (sk)
while (pos && (sk = udp_get_next(seq, sk)) != NULL)
--pos;
return pos ? NULL : sk;
}

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

return *pos ? udp_get_idx(seq, *pos-1) : SEQ_START_TOKEN;
}

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

if (v == SEQ_START_TOKEN)
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)
{
struct udp_iter_state *state = seq->private;

if (state->bucket <= state->udp_table->mask)
spin_unlock_bh(&state->udp_table->hash[state->bucket].lock);
}

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

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

s = ((struct seq_file *)file->private_data)->private;
s->family = afinfo->family;
s->udp_table = afinfo->udp_table;
return err;
}
EXPORT_SYMBOL(udp_seq_open);

/* ------------------------------------------------------------------------ */
int udp_proc_register(struct net *net, struct udp_seq_afinfo *afinfo)
{
struct proc_dir_entry *p;
int rc = 0;

afinfo->seq_ops.start = udp_seq_start;
afinfo->seq_ops.next = udp_seq_next;
afinfo->seq_ops.stop = udp_seq_stop;

p = proc_create_data(afinfo->name, S_IRUGO, net->proc_net,
afinfo->seq_fops, afinfo);
if (!p)
rc = -ENOMEM;
return rc;
}
EXPORT_SYMBOL(udp_proc_register);

void udp_proc_unregister(struct net *net, struct udp_seq_afinfo *afinfo)
{
proc_net_remove(net, afinfo->name);
}
EXPORT_SYMBOL(udp_proc_unregister);

/* ------------------------------------------------------------------------ */
static void udp4_format_sock(struct sock *sp, struct seq_file *f,
int bucket, int *len)
{
struct inet_sock *inet = inet_sk(sp);
__be32 dest = inet->inet_daddr;
__be32 src = inet->inet_rcv_saddr;
__u16 destp = ntohs(inet->inet_dport);
__u16 srcp = ntohs(inet->inet_sport);

seq_printf(f, "%5d: %08X:%04X %08X:%04X"
" %02X %08X:%08X %02X:%08lX %08X %5d %8d %lu %d %pK %d%n",
bucket, src, srcp, dest, destp, sp->sk_state,
sk_wmem_alloc_get(sp),
sk_rmem_alloc_get(sp),
0, 0L, 0, sock_i_uid(sp), 0, sock_i_ino(sp),
atomic_read(&sp->sk_refcnt), sp,
atomic_read(&sp->sk_drops), len);
}

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

udp4_format_sock(v, seq, state->bucket, &len);
seq_printf(seq, "%*s\n", 127 - len, "");
}
return 0;
}

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
};

/* ------------------------------------------------------------------------ */
static struct udp_seq_afinfo udp4_seq_afinfo = {
.name = "udp",
.family = AF_INET,
.udp_table = &udp_table,
.seq_fops = &udp_afinfo_seq_fops,
.seq_ops = {
.show = udp4_seq_show,
},
};

static int __net_init udp4_proc_init_net(struct net *net)
{
return udp_proc_register(net, &udp4_seq_afinfo);
}

static void __net_exit 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,
};

int __init udp4_proc_init(void)
{
return register_pernet_subsys(&udp4_net_ops);
}

void udp4_proc_exit(void)
{
unregister_pernet_subsys(&udp4_net_ops);
}
#endif /* CONFIG_PROC_FS */

static __initdata unsigned long uhash_entries;
static int __init set_uhash_entries(char *str)
{
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);

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,
2 * 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 *
2 * 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;
}
table->hash2 = table->hash + (table->mask + 1);
for (i = 0; i <= table->mask; i++) {
INIT_HLIST_NULLS_HEAD(&table->hash[i].head, i);
table->hash[i].count = 0;
spin_lock_init(&table->hash[i].lock);
}
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);
}
}

void __init udp_init(void)
{
unsigned long limit;

udp_table_init(&udp_table, "UDP");
limit = nr_free_buffer_pages() / 8;
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;
}

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, u32 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_checksum_start_offset(skb);
csum = skb_checksum(skb, offset, skb->len - offset, 0);
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;
}

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