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linux-next/net/ipv4/udp.c
David S. Miller 38e406f600 Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf 
Daniel Borkmann says:

====================
pull-request: bpf 2019-06-07

The following pull-request contains BPF updates for your *net* tree.

The main changes are:

1) Fix several bugs in riscv64 JIT code emission which forgot to clear high
   32-bits for alu32 ops, from Björn and Luke with selftests covering all
   relevant BPF alu ops from Björn and Jiong.

2) Two fixes for UDP BPF reuseport that avoid calling the program in case of
   __udp6_lib_err and UDP GRO which broke reuseport_select_sock() assumption
   that skb->data is pointing to transport header, from Martin.

3) Two fixes for BPF sockmap: a use-after-free from sleep in psock's backlog
   workqueue, and a missing restore of sk_write_space when psock gets dropped,
   from Jakub and John.

4) Fix unconnected UDP sendmsg hook API which is insufficient as-is since it
   breaks standard applications like DNS if reverse NAT is not performed upon
   receive, from Daniel.

5) Fix an out-of-bounds read in __bpf_skc_lookup which in case of AF_INET6
   fails to verify that the length of the tuple is long enough, from Lorenz.

6) Fix libbpf's libbpf__probe_raw_btf to return an fd instead of 0/1 (for
   {un,}successful probe) as that is expected to be propagated as an fd to
   load_sk_storage_btf() and thus closing the wrong descriptor otherwise,
   from Michal.

7) Fix bpftool's JSON output for the case when a lookup fails, from Krzesimir.

8) Minor misc fixes in docs, samples and selftests, from various others.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
2019-06-07 14:46:47 -07:00

3058 lines
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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* 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.
*/
#define pr_fmt(fmt) "UDP: " fmt
#include <linux/uaccess.h>
#include <asm/ioctls.h>
#include <linux/memblock.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/inetdevice.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/inet_hashtables.h>
#include <net/ip_tunnels.h>
#include <net/route.h>
#include <net/checksum.h>
#include <net/xfrm.h>
#include <trace/events/udp.h>
#include <linux/static_key.h>
#include <trace/events/skb.h>
#include <net/busy_poll.h>
#include "udp_impl.h"
#include <net/sock_reuseport.h>
#include <net/addrconf.h>
#include <net/udp_tunnel.h>
struct udp_table udp_table __read_mostly;
EXPORT_SYMBOL(udp_table);
long sysctl_udp_mem[3] __read_mostly;
EXPORT_SYMBOL(sysctl_udp_mem);
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)
/* IPCB reference means this can not be used from early demux */
static bool udp_lib_exact_dif_match(struct net *net, struct sk_buff *skb)
{
#if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
if (!net->ipv4.sysctl_udp_l3mdev_accept &&
skb && ipv4_l3mdev_skb(IPCB(skb)->flags))
return true;
#endif
return false;
}
static int udp_lib_lport_inuse(struct net *net, __u16 num,
const struct udp_hslot *hslot,
unsigned long *bitmap,
struct sock *sk, unsigned int log)
{
struct sock *sk2;
kuid_t uid = sock_i_uid(sk);
sk_for_each(sk2, &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) &&
inet_rcv_saddr_equal(sk, sk2, true)) {
if (sk2->sk_reuseport && sk->sk_reuseport &&
!rcu_access_pointer(sk->sk_reuseport_cb) &&
uid_eq(uid, sock_i_uid(sk2))) {
if (!bitmap)
return 0;
} else {
if (!bitmap)
return 1;
__set_bit(udp_sk(sk2)->udp_port_hash >> log,
bitmap);
}
}
}
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)
{
struct sock *sk2;
kuid_t uid = sock_i_uid(sk);
int res = 0;
spin_lock(&hslot2->lock);
udp_portaddr_for_each_entry(sk2, &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) &&
inet_rcv_saddr_equal(sk, sk2, true)) {
if (sk2->sk_reuseport && sk->sk_reuseport &&
!rcu_access_pointer(sk->sk_reuseport_cb) &&
uid_eq(uid, sock_i_uid(sk2))) {
res = 0;
} else {
res = 1;
}
break;
}
}
spin_unlock(&hslot2->lock);
return res;
}
static int udp_reuseport_add_sock(struct sock *sk, struct udp_hslot *hslot)
{
struct net *net = sock_net(sk);
kuid_t uid = sock_i_uid(sk);
struct sock *sk2;
sk_for_each(sk2, &hslot->head) {
if (net_eq(sock_net(sk2), net) &&
sk2 != sk &&
sk2->sk_family == sk->sk_family &&
ipv6_only_sock(sk2) == ipv6_only_sock(sk) &&
(udp_sk(sk2)->udp_port_hash == udp_sk(sk)->udp_port_hash) &&
(sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
sk2->sk_reuseport && uid_eq(uid, sock_i_uid(sk2)) &&
inet_rcv_saddr_equal(sk, sk2, false)) {
return reuseport_add_sock(sk, sk2,
inet_rcv_saddr_any(sk));
}
}
return reuseport_alloc(sk, inet_rcv_saddr_any(sk));
}
/**
* udp_lib_get_port - UDP/-Lite port lookup for IPv4 and IPv6
*
* @sk: socket struct in question
* @snum: port number to look up
* @hash2_nulladdr: AF-dependent hash value in secondary hash chains,
* with NULL address
*/
int udp_lib_get_port(struct sock *sk, unsigned short snum,
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 int rand;
unsigned short first, last;
DECLARE_BITMAP(bitmap, PORTS_PER_CHAIN);
inet_get_local_port_range(net, &low, &high);
remaining = (high - low) + 1;
rand = prandom_u32();
first = reciprocal_scale(rand, remaining) + 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,
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_local_reserved_port(net, snum))
goto found;
snum += rand;
} while (snum != first);
spin_unlock_bh(&hslot->lock);
cond_resched();
} 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);
if (!exist && (hash2_nulladdr != slot2)) {
hslot2 = udp_hashslot2(udptable, hash2_nulladdr);
exist = udp_lib_lport_inuse2(net, snum, hslot2,
sk);
}
if (exist)
goto fail_unlock;
else
goto found;
}
scan_primary_hash:
if (udp_lib_lport_inuse(net, snum, hslot, NULL, sk, 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)) {
if (sk->sk_reuseport &&
udp_reuseport_add_sock(sk, hslot)) {
inet_sk(sk)->inet_num = 0;
udp_sk(sk)->udp_port_hash = 0;
udp_sk(sk)->udp_portaddr_hash ^= snum;
goto fail_unlock;
}
sk_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);
if (IS_ENABLED(CONFIG_IPV6) && sk->sk_reuseport &&
sk->sk_family == AF_INET6)
hlist_add_tail_rcu(&udp_sk(sk)->udp_portaddr_node,
&hslot2->head);
else
hlist_add_head_rcu(&udp_sk(sk)->udp_portaddr_node,
&hslot2->head);
hslot2->count++;
spin_unlock(&hslot2->lock);
}
sock_set_flag(sk, SOCK_RCU_FREE);
error = 0;
fail_unlock:
spin_unlock_bh(&hslot->lock);
fail:
return error;
}
EXPORT_SYMBOL(udp_lib_get_port);
int udp_v4_get_port(struct sock *sk, unsigned short snum)
{
unsigned int hash2_nulladdr =
ipv4_portaddr_hash(sock_net(sk), htonl(INADDR_ANY), snum);
unsigned int hash2_partial =
ipv4_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, hash2_nulladdr);
}
static int compute_score(struct sock *sk, struct net *net,
__be32 saddr, __be16 sport,
__be32 daddr, unsigned short hnum,
int dif, int sdif, bool exact_dif)
{
int score;
struct inet_sock *inet;
bool dev_match;
if (!net_eq(sock_net(sk), net) ||
udp_sk(sk)->udp_port_hash != hnum ||
ipv6_only_sock(sk))
return -1;
if (sk->sk_rcv_saddr != daddr)
return -1;
score = (sk->sk_family == PF_INET) ? 2 : 1;
inet = inet_sk(sk);
if (inet->inet_daddr) {
if (inet->inet_daddr != saddr)
return -1;
score += 4;
}
if (inet->inet_dport) {
if (inet->inet_dport != sport)
return -1;
score += 4;
}
dev_match = udp_sk_bound_dev_eq(net, sk->sk_bound_dev_if,
dif, sdif);
if (!dev_match)
return -1;
score += 4;
if (sk->sk_incoming_cpu == raw_smp_processor_id())
score++;
return score;
}
static u32 udp_ehashfn(const struct net *net, const __be32 laddr,
const __u16 lport, const __be32 faddr,
const __be16 fport)
{
static u32 udp_ehash_secret __read_mostly;
net_get_random_once(&udp_ehash_secret, sizeof(udp_ehash_secret));
return __inet_ehashfn(laddr, lport, faddr, fport,
udp_ehash_secret + net_hash_mix(net));
}
/* called with rcu_read_lock() */
static struct sock *udp4_lib_lookup2(struct net *net,
__be32 saddr, __be16 sport,
__be32 daddr, unsigned int hnum,
int dif, int sdif, bool exact_dif,
struct udp_hslot *hslot2,
struct sk_buff *skb)
{
struct sock *sk, *result;
int score, badness;
u32 hash = 0;
result = NULL;
badness = 0;
udp_portaddr_for_each_entry_rcu(sk, &hslot2->head) {
score = compute_score(sk, net, saddr, sport,
daddr, hnum, dif, sdif, exact_dif);
if (score > badness) {
if (sk->sk_reuseport) {
hash = udp_ehashfn(net, daddr, hnum,
saddr, sport);
result = reuseport_select_sock(sk, hash, skb,
sizeof(struct udphdr));
if (result)
return result;
}
badness = score;
result = sk;
}
}
return result;
}
/* UDP is nearly always wildcards out the wazoo, it makes no sense to try
* harder than this. -DaveM
*/
struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr,
__be16 sport, __be32 daddr, __be16 dport, int dif,
int sdif, struct udp_table *udptable, struct sk_buff *skb)
{
struct sock *result;
unsigned short hnum = ntohs(dport);
unsigned int hash2, slot2;
struct udp_hslot *hslot2;
bool exact_dif = udp_lib_exact_dif_match(net, skb);
hash2 = ipv4_portaddr_hash(net, daddr, hnum);
slot2 = hash2 & udptable->mask;
hslot2 = &udptable->hash2[slot2];
result = udp4_lib_lookup2(net, saddr, sport,
daddr, hnum, dif, sdif,
exact_dif, hslot2, skb);
if (!result) {
hash2 = ipv4_portaddr_hash(net, htonl(INADDR_ANY), hnum);
slot2 = hash2 & udptable->mask;
hslot2 = &udptable->hash2[slot2];
result = udp4_lib_lookup2(net, saddr, sport,
htonl(INADDR_ANY), hnum, dif, sdif,
exact_dif, hslot2, skb);
}
if (unlikely(IS_ERR(result)))
return NULL;
return result;
}
EXPORT_SYMBOL_GPL(__udp4_lib_lookup);
static inline struct sock *__udp4_lib_lookup_skb(struct sk_buff *skb,
__be16 sport, __be16 dport,
struct udp_table *udptable)
{
const struct iphdr *iph = ip_hdr(skb);
return __udp4_lib_lookup(dev_net(skb->dev), iph->saddr, sport,
iph->daddr, dport, inet_iif(skb),
inet_sdif(skb), udptable, skb);
}
struct sock *udp4_lib_lookup_skb(struct sk_buff *skb,
__be16 sport, __be16 dport)
{
const struct iphdr *iph = ip_hdr(skb);
return __udp4_lib_lookup(dev_net(skb->dev), iph->saddr, sport,
iph->daddr, dport, inet_iif(skb),
inet_sdif(skb), &udp_table, NULL);
}
EXPORT_SYMBOL_GPL(udp4_lib_lookup_skb);
/* Must be called under rcu_read_lock().
* Does increment socket refcount.
*/
#if IS_ENABLED(CONFIG_NF_TPROXY_IPV4) || IS_ENABLED(CONFIG_NF_SOCKET_IPV4)
struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
__be32 daddr, __be16 dport, int dif)
{
struct sock *sk;
sk = __udp4_lib_lookup(net, saddr, sport, daddr, dport,
dif, 0, &udp_table, NULL);
if (sk && !refcount_inc_not_zero(&sk->sk_refcnt))
sk = NULL;
return sk;
}
EXPORT_SYMBOL_GPL(udp4_lib_lookup);
#endif
static inline bool __udp_is_mcast_sock(struct net *net, struct sock *sk,
__be16 loc_port, __be32 loc_addr,
__be16 rmt_port, __be32 rmt_addr,
int dif, int sdif, unsigned short hnum)
{
struct inet_sock *inet = inet_sk(sk);
if (!net_eq(sock_net(sk), net) ||
udp_sk(sk)->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(sk) ||
!udp_sk_bound_dev_eq(net, sk->sk_bound_dev_if, dif, sdif))
return false;
if (!ip_mc_sf_allow(sk, loc_addr, rmt_addr, dif, sdif))
return false;
return true;
}
DEFINE_STATIC_KEY_FALSE(udp_encap_needed_key);
void udp_encap_enable(void)
{
static_branch_inc(&udp_encap_needed_key);
}
EXPORT_SYMBOL(udp_encap_enable);
/* Handler for tunnels with arbitrary destination ports: no socket lookup, go
* through error handlers in encapsulations looking for a match.
*/
static int __udp4_lib_err_encap_no_sk(struct sk_buff *skb, u32 info)
{
int i;
for (i = 0; i < MAX_IPTUN_ENCAP_OPS; i++) {
int (*handler)(struct sk_buff *skb, u32 info);
const struct ip_tunnel_encap_ops *encap;
encap = rcu_dereference(iptun_encaps[i]);
if (!encap)
continue;
handler = encap->err_handler;
if (handler && !handler(skb, info))
return 0;
}
return -ENOENT;
}
/* Try to match ICMP errors to UDP tunnels by looking up a socket without
* reversing source and destination port: this will match tunnels that force the
* same destination port on both endpoints (e.g. VXLAN, GENEVE). Note that
* lwtunnels might actually break this assumption by being configured with
* different destination ports on endpoints, in this case we won't be able to
* trace ICMP messages back to them.
*
* If this doesn't match any socket, probe tunnels with arbitrary destination
* ports (e.g. FoU, GUE): there, the receiving socket is useless, as the port
* we've sent packets to won't necessarily match the local destination port.
*
* Then ask the tunnel implementation to match the error against a valid
* association.
*
* Return an error if we can't find a match, the socket if we need further
* processing, zero otherwise.
*/
static struct sock *__udp4_lib_err_encap(struct net *net,
const struct iphdr *iph,
struct udphdr *uh,
struct udp_table *udptable,
struct sk_buff *skb, u32 info)
{
int network_offset, transport_offset;
struct sock *sk;
network_offset = skb_network_offset(skb);
transport_offset = skb_transport_offset(skb);
/* Network header needs to point to the outer IPv4 header inside ICMP */
skb_reset_network_header(skb);
/* Transport header needs to point to the UDP header */
skb_set_transport_header(skb, iph->ihl << 2);
sk = __udp4_lib_lookup(net, iph->daddr, uh->source,
iph->saddr, uh->dest, skb->dev->ifindex, 0,
udptable, NULL);
if (sk) {
int (*lookup)(struct sock *sk, struct sk_buff *skb);
struct udp_sock *up = udp_sk(sk);
lookup = READ_ONCE(up->encap_err_lookup);
if (!lookup || lookup(sk, skb))
sk = NULL;
}
if (!sk)
sk = ERR_PTR(__udp4_lib_err_encap_no_sk(skb, info));
skb_set_transport_header(skb, transport_offset);
skb_set_network_header(skb, network_offset);
return sk;
}
/*
* 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.
*/
int __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;
bool tunnel = false;
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,
inet_sdif(skb), udptable, NULL);
if (!sk) {
/* No socket for error: try tunnels before discarding */
sk = ERR_PTR(-ENOENT);
if (static_branch_unlikely(&udp_encap_needed_key)) {
sk = __udp4_lib_err_encap(net, iph, uh, udptable, skb,
info);
if (!sk)
return 0;
}
if (IS_ERR(sk)) {
__ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
return PTR_ERR(sk);
}
tunnel = true;
}
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 */
ipv4_sk_update_pmtu(skb, sk, info);
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;
case ICMP_REDIRECT:
ipv4_sk_redirect(skb, sk);
goto out;
}
/*
* RFC1122: OK. Passes ICMP errors back to application, as per
* 4.1.3.3.
*/
if (tunnel) {
/* ...not for tunnels though: we don't have a sending socket */
goto out;
}
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:
return 0;
}
int udp_err(struct sk_buff *skb, u32 info)
{
return __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
*/
void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst)
{
struct udphdr *uh = udp_hdr(skb);
int offset = skb_transport_offset(skb);
int len = skb->len - offset;
int hlen = len;
__wsum csum = 0;
if (!skb_has_frag_list(skb)) {
/*
* 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 {
struct sk_buff *frags;
/*
* 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
*/
skb_walk_frags(skb, frags) {
csum = csum_add(csum, frags->csum);
hlen -= frags->len;
}
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;
}
}
EXPORT_SYMBOL_GPL(udp4_hwcsum);
/* Function to set UDP checksum for an IPv4 UDP packet. This is intended
* for the simple case like when setting the checksum for a UDP tunnel.
*/
void udp_set_csum(bool nocheck, struct sk_buff *skb,
__be32 saddr, __be32 daddr, int len)
{
struct udphdr *uh = udp_hdr(skb);
if (nocheck) {
uh->check = 0;
} else if (skb_is_gso(skb)) {
uh->check = ~udp_v4_check(len, saddr, daddr, 0);
} else if (skb->ip_summed == CHECKSUM_PARTIAL) {
uh->check = 0;
uh->check = udp_v4_check(len, saddr, daddr, lco_csum(skb));
if (uh->check == 0)
uh->check = CSUM_MANGLED_0;
} else {
skb->ip_summed = CHECKSUM_PARTIAL;
skb->csum_start = skb_transport_header(skb) - skb->head;
skb->csum_offset = offsetof(struct udphdr, check);
uh->check = ~udp_v4_check(len, saddr, daddr, 0);
}
}
EXPORT_SYMBOL(udp_set_csum);
static int udp_send_skb(struct sk_buff *skb, struct flowi4 *fl4,
struct inet_cork *cork)
{
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 (cork->gso_size) {
const int hlen = skb_network_header_len(skb) +
sizeof(struct udphdr);
if (hlen + cork->gso_size > cork->fragsize) {
kfree_skb(skb);
return -EINVAL;
}
if (skb->len > cork->gso_size * UDP_MAX_SEGMENTS) {
kfree_skb(skb);
return -EINVAL;
}
if (sk->sk_no_check_tx) {
kfree_skb(skb);
return -EINVAL;
}
if (skb->ip_summed != CHECKSUM_PARTIAL || is_udplite ||
dst_xfrm(skb_dst(skb))) {
kfree_skb(skb);
return -EIO;
}
skb_shinfo(skb)->gso_size = cork->gso_size;
skb_shinfo(skb)->gso_type = SKB_GSO_UDP_L4;
skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(len - sizeof(uh),
cork->gso_size);
goto csum_partial;
}
if (is_udplite) /* UDP-Lite */
csum = udplite_csum(skb);
else if (sk->sk_no_check_tx) { /* UDP csum off */
skb->ip_summed = CHECKSUM_NONE;
goto send;
} else if (skb->ip_summed == CHECKSUM_PARTIAL) { /* UDP hardware csum */
csum_partial:
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(sock_net(sk), skb);
if (err) {
if (err == -ENOBUFS && !inet->recverr) {
UDP_INC_STATS(sock_net(sk),
UDP_MIB_SNDBUFERRORS, is_udplite);
err = 0;
}
} else
UDP_INC_STATS(sock_net(sk),
UDP_MIB_OUTDATAGRAMS, is_udplite);
return err;
}
/*
* Push out all pending data as one UDP datagram. Socket is locked.
*/
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, &inet->cork.base);
out:
up->len = 0;
up->pending = 0;
return err;
}
EXPORT_SYMBOL(udp_push_pending_frames);
static int __udp_cmsg_send(struct cmsghdr *cmsg, u16 *gso_size)
{
switch (cmsg->cmsg_type) {
case UDP_SEGMENT:
if (cmsg->cmsg_len != CMSG_LEN(sizeof(__u16)))
return -EINVAL;
*gso_size = *(__u16 *)CMSG_DATA(cmsg);
return 0;
default:
return -EINVAL;
}
}
int udp_cmsg_send(struct sock *sk, struct msghdr *msg, u16 *gso_size)
{
struct cmsghdr *cmsg;
bool need_ip = false;
int err;
for_each_cmsghdr(cmsg, msg) {
if (!CMSG_OK(msg, cmsg))
return -EINVAL;
if (cmsg->cmsg_level != SOL_UDP) {
need_ip = true;
continue;
}
err = __udp_cmsg_send(cmsg, gso_size);
if (err)
return err;
}
return need_ip;
}
EXPORT_SYMBOL_GPL(udp_cmsg_send);
int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
{
struct inet_sock *inet = inet_sk(sk);
struct udp_sock *up = udp_sk(sk);
DECLARE_SOCKADDR(struct sockaddr_in *, usin, msg->msg_name);
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;
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 (usin) {
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;
}
ipcm_init_sk(&ipc, inet);
ipc.gso_size = up->gso_size;
if (msg->msg_controllen) {
err = udp_cmsg_send(sk, msg, &ipc.gso_size);
if (err > 0)
err = ip_cmsg_send(sk, msg, &ipc,
sk->sk_family == AF_INET6);
if (unlikely(err < 0)) {
kfree(ipc.opt);
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();
}
if (cgroup_bpf_enabled && !connected) {
err = BPF_CGROUP_RUN_PROG_UDP4_SENDMSG_LOCK(sk,
(struct sockaddr *)usin, &ipc.addr);
if (err)
goto out_free;
if (usin) {
if (usin->sin_port == 0) {
/* BPF program set invalid port. Reject it. */
err = -EINVAL;
goto out_free;
}
daddr = usin->sin_addr.s_addr;
dport = usin->sin_port;
}
}
saddr = ipc.addr;
ipc.addr = faddr = daddr;
if (ipc.opt && ipc.opt->opt.srr) {
if (!daddr) {
err = -EINVAL;
goto out_free;
}
faddr = ipc.opt->opt.faddr;
connected = 0;
}
tos = get_rttos(&ipc, inet);
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 || netif_index_is_l3_master(sock_net(sk), ipc.oif))
ipc.oif = inet->mc_index;
if (!saddr)
saddr = inet->mc_addr;
connected = 0;
} else if (!ipc.oif) {
ipc.oif = inet->uc_index;
} else if (ipv4_is_lbcast(daddr) && inet->uc_index) {
/* oif is set, packet is to local broadcast and
* and uc_index is set. oif is most likely set
* by sk_bound_dev_if. If uc_index != oif check if the
* oif is an L3 master and uc_index is an L3 slave.
* If so, we want to allow the send using the uc_index.
*/
if (ipc.oif != inet->uc_index &&
ipc.oif == l3mdev_master_ifindex_by_index(sock_net(sk),
inet->uc_index)) {
ipc.oif = inet->uc_index;
}
}
if (connected)
rt = (struct rtable *)sk_dst_check(sk, 0);
if (!rt) {
struct net *net = sock_net(sk);
__u8 flow_flags = inet_sk_flowi_flags(sk);
fl4 = &fl4_stack;
flowi4_init_output(fl4, ipc.oif, sk->sk_mark, tos,
RT_SCOPE_UNIVERSE, sk->sk_protocol,
flow_flags,
faddr, saddr, dport, inet->inet_sport,
sk->sk_uid);
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(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) {
struct inet_cork cork;
skb = ip_make_skb(sk, fl4, getfrag, msg, ulen,
sizeof(struct udphdr), &ipc, &rt,
&cork, msg->msg_flags);
err = PTR_ERR(skb);
if (!IS_ERR_OR_NULL(skb))
err = udp_send_skb(skb, fl4, &cork);
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);
net_dbg_ratelimited("socket already corked\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, 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);
out_free:
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(sock_net(sk),
UDP_MIB_SNDBUFERRORS, is_udplite);
}
return err;
do_confirm:
if (msg->msg_flags & MSG_PROBE)
dst_confirm_neigh(&rt->dst, &fl4->daddr);
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 (flags & MSG_SENDPAGE_NOTLAST)
flags |= MSG_MORE;
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(sk, &msg, 0);
if (ret < 0)
return ret;
}
lock_sock(sk);
if (unlikely(!up->pending)) {
release_sock(sk);
net_dbg_ratelimited("cork failed\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;
}
#define UDP_SKB_IS_STATELESS 0x80000000
static void udp_set_dev_scratch(struct sk_buff *skb)
{
struct udp_dev_scratch *scratch = udp_skb_scratch(skb);
BUILD_BUG_ON(sizeof(struct udp_dev_scratch) > sizeof(long));
scratch->_tsize_state = skb->truesize;
#if BITS_PER_LONG == 64
scratch->len = skb->len;
scratch->csum_unnecessary = !!skb_csum_unnecessary(skb);
scratch->is_linear = !skb_is_nonlinear(skb);
#endif
/* all head states execept sp (dst, sk, nf) are always cleared by
* udp_rcv() and we need to preserve secpath, if present, to eventually
* process IP_CMSG_PASSSEC at recvmsg() time
*/
if (likely(!skb_sec_path(skb)))
scratch->_tsize_state |= UDP_SKB_IS_STATELESS;
}
static int udp_skb_truesize(struct sk_buff *skb)
{
return udp_skb_scratch(skb)->_tsize_state & ~UDP_SKB_IS_STATELESS;
}
static bool udp_skb_has_head_state(struct sk_buff *skb)
{
return !(udp_skb_scratch(skb)->_tsize_state & UDP_SKB_IS_STATELESS);
}
/* fully reclaim rmem/fwd memory allocated for skb */
static void udp_rmem_release(struct sock *sk, int size, int partial,
bool rx_queue_lock_held)
{
struct udp_sock *up = udp_sk(sk);
struct sk_buff_head *sk_queue;
int amt;
if (likely(partial)) {
up->forward_deficit += size;
size = up->forward_deficit;
if (size < (sk->sk_rcvbuf >> 2))
return;
} else {
size += up->forward_deficit;
}
up->forward_deficit = 0;
/* acquire the sk_receive_queue for fwd allocated memory scheduling,
* if the called don't held it already
*/
sk_queue = &sk->sk_receive_queue;
if (!rx_queue_lock_held)
spin_lock(&sk_queue->lock);
sk->sk_forward_alloc += size;
amt = (sk->sk_forward_alloc - partial) & ~(SK_MEM_QUANTUM - 1);
sk->sk_forward_alloc -= amt;
if (amt)
__sk_mem_reduce_allocated(sk, amt >> SK_MEM_QUANTUM_SHIFT);
atomic_sub(size, &sk->sk_rmem_alloc);
/* this can save us from acquiring the rx queue lock on next receive */
skb_queue_splice_tail_init(sk_queue, &up->reader_queue);
if (!rx_queue_lock_held)
spin_unlock(&sk_queue->lock);
}
/* Note: called with reader_queue.lock held.
* Instead of using skb->truesize here, find a copy of it in skb->dev_scratch
* This avoids a cache line miss while receive_queue lock is held.
* Look at __udp_enqueue_schedule_skb() to find where this copy is done.
*/
void udp_skb_destructor(struct sock *sk, struct sk_buff *skb)
{
prefetch(&skb->data);
udp_rmem_release(sk, udp_skb_truesize(skb), 1, false);
}
EXPORT_SYMBOL(udp_skb_destructor);
/* as above, but the caller held the rx queue lock, too */
static void udp_skb_dtor_locked(struct sock *sk, struct sk_buff *skb)
{
prefetch(&skb->data);
udp_rmem_release(sk, udp_skb_truesize(skb), 1, true);
}
/* Idea of busylocks is to let producers grab an extra spinlock
* to relieve pressure on the receive_queue spinlock shared by consumer.
* Under flood, this means that only one producer can be in line
* trying to acquire the receive_queue spinlock.
* These busylock can be allocated on a per cpu manner, instead of a
* per socket one (that would consume a cache line per socket)
*/
static int udp_busylocks_log __read_mostly;
static spinlock_t *udp_busylocks __read_mostly;
static spinlock_t *busylock_acquire(void *ptr)
{
spinlock_t *busy;
busy = udp_busylocks + hash_ptr(ptr, udp_busylocks_log);
spin_lock(busy);
return busy;
}
static void busylock_release(spinlock_t *busy)
{
if (busy)
spin_unlock(busy);
}
int __udp_enqueue_schedule_skb(struct sock *sk, struct sk_buff *skb)
{
struct sk_buff_head *list = &sk->sk_receive_queue;
int rmem, delta, amt, err = -ENOMEM;
spinlock_t *busy = NULL;
int size;
/* try to avoid the costly atomic add/sub pair when the receive
* queue is full; always allow at least a packet
*/
rmem = atomic_read(&sk->sk_rmem_alloc);
if (rmem > sk->sk_rcvbuf)
goto drop;
/* Under mem pressure, it might be helpful to help udp_recvmsg()
* having linear skbs :
* - Reduce memory overhead and thus increase receive queue capacity
* - Less cache line misses at copyout() time
* - Less work at consume_skb() (less alien page frag freeing)
*/
if (rmem > (sk->sk_rcvbuf >> 1)) {
skb_condense(skb);
busy = busylock_acquire(sk);
}
size = skb->truesize;
udp_set_dev_scratch(skb);
/* we drop only if the receive buf is full and the receive
* queue contains some other skb
*/
rmem = atomic_add_return(size, &sk->sk_rmem_alloc);
if (rmem > (size + sk->sk_rcvbuf))
goto uncharge_drop;
spin_lock(&list->lock);
if (size >= sk->sk_forward_alloc) {
amt = sk_mem_pages(size);
delta = amt << SK_MEM_QUANTUM_SHIFT;
if (!__sk_mem_raise_allocated(sk, delta, amt, SK_MEM_RECV)) {
err = -ENOBUFS;
spin_unlock(&list->lock);
goto uncharge_drop;
}
sk->sk_forward_alloc += delta;
}
sk->sk_forward_alloc -= size;
/* no need to setup a destructor, we will explicitly release the
* forward allocated memory on dequeue
*/
sock_skb_set_dropcount(sk, skb);
__skb_queue_tail(list, skb);
spin_unlock(&list->lock);
if (!sock_flag(sk, SOCK_DEAD))
sk->sk_data_ready(sk);
busylock_release(busy);
return 0;
uncharge_drop:
atomic_sub(skb->truesize, &sk->sk_rmem_alloc);
drop:
atomic_inc(&sk->sk_drops);
busylock_release(busy);
return err;
}
EXPORT_SYMBOL_GPL(__udp_enqueue_schedule_skb);
void udp_destruct_sock(struct sock *sk)
{
/* reclaim completely the forward allocated memory */
struct udp_sock *up = udp_sk(sk);
unsigned int total = 0;
struct sk_buff *skb;
skb_queue_splice_tail_init(&sk->sk_receive_queue, &up->reader_queue);
while ((skb = __skb_dequeue(&up->reader_queue)) != NULL) {
total += skb->truesize;
kfree_skb(skb);
}
udp_rmem_release(sk, total, 0, true);
inet_sock_destruct(sk);
}
EXPORT_SYMBOL_GPL(udp_destruct_sock);
int udp_init_sock(struct sock *sk)
{
skb_queue_head_init(&udp_sk(sk)->reader_queue);
sk->sk_destruct = udp_destruct_sock;
return 0;
}
EXPORT_SYMBOL_GPL(udp_init_sock);
void skb_consume_udp(struct sock *sk, struct sk_buff *skb, int len)
{
if (unlikely(READ_ONCE(sk->sk_peek_off) >= 0)) {
bool slow = lock_sock_fast(sk);
sk_peek_offset_bwd(sk, len);
unlock_sock_fast(sk, slow);
}
if (!skb_unref(skb))
return;
/* In the more common cases we cleared the head states previously,
* see __udp_queue_rcv_skb().
*/
if (unlikely(udp_skb_has_head_state(skb)))
skb_release_head_state(skb);
__consume_stateless_skb(skb);
}
EXPORT_SYMBOL_GPL(skb_consume_udp);
static struct sk_buff *__first_packet_length(struct sock *sk,
struct sk_buff_head *rcvq,
int *total)
{
struct sk_buff *skb;
while ((skb = skb_peek(rcvq)) != NULL) {
if (udp_lib_checksum_complete(skb)) {
__UDP_INC_STATS(sock_net(sk), UDP_MIB_CSUMERRORS,
IS_UDPLITE(sk));
__UDP_INC_STATS(sock_net(sk), UDP_MIB_INERRORS,
IS_UDPLITE(sk));
atomic_inc(&sk->sk_drops);
__skb_unlink(skb, rcvq);
*total += skb->truesize;
kfree_skb(skb);
} else {
/* the csum related bits could be changed, refresh
* the scratch area
*/
udp_set_dev_scratch(skb);
break;
}
}
return skb;
}
/**
* 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 -1 if none is found.
*/
static int first_packet_length(struct sock *sk)
{
struct sk_buff_head *rcvq = &udp_sk(sk)->reader_queue;
struct sk_buff_head *sk_queue = &sk->sk_receive_queue;
struct sk_buff *skb;
int total = 0;
int res;
spin_lock_bh(&rcvq->lock);
skb = __first_packet_length(sk, rcvq, &total);
if (!skb && !skb_queue_empty(sk_queue)) {
spin_lock(&sk_queue->lock);
skb_queue_splice_tail_init(sk_queue, rcvq);
spin_unlock(&sk_queue->lock);
skb = __first_packet_length(sk, rcvq, &total);
}
res = skb ? skb->len : -1;
if (total)
udp_rmem_release(sk, total, 1, false);
spin_unlock_bh(&rcvq->lock);
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:
{
int amount = max_t(int, 0, first_packet_length(sk));
return put_user(amount, (int __user *)arg);
}
default:
return -ENOIOCTLCMD;
}
return 0;
}
EXPORT_SYMBOL(udp_ioctl);
struct sk_buff *__skb_recv_udp(struct sock *sk, unsigned int flags,
int noblock, int *off, int *err)
{
struct sk_buff_head *sk_queue = &sk->sk_receive_queue;
struct sk_buff_head *queue;
struct sk_buff *last;
long timeo;
int error;
queue = &udp_sk(sk)->reader_queue;
flags |= noblock ? MSG_DONTWAIT : 0;
timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
do {
struct sk_buff *skb;
error = sock_error(sk);
if (error)
break;
error = -EAGAIN;
do {
spin_lock_bh(&queue->lock);
skb = __skb_try_recv_from_queue(sk, queue, flags,
udp_skb_destructor,
off, err, &last);
if (skb) {
spin_unlock_bh(&queue->lock);
return skb;
}
if (skb_queue_empty(sk_queue)) {
spin_unlock_bh(&queue->lock);
goto busy_check;
}
/* refill the reader queue and walk it again
* keep both queues locked to avoid re-acquiring
* the sk_receive_queue lock if fwd memory scheduling
* is needed.
*/
spin_lock(&sk_queue->lock);
skb_queue_splice_tail_init(sk_queue, queue);
skb = __skb_try_recv_from_queue(sk, queue, flags,
udp_skb_dtor_locked,
off, err, &last);
spin_unlock(&sk_queue->lock);
spin_unlock_bh(&queue->lock);
if (skb)
return skb;
busy_check:
if (!sk_can_busy_loop(sk))
break;
sk_busy_loop(sk, flags & MSG_DONTWAIT);
} while (!skb_queue_empty(sk_queue));
/* sk_queue is empty, reader_queue may contain peeked packets */
} while (timeo &&
!__skb_wait_for_more_packets(sk, &error, &timeo,
(struct sk_buff *)sk_queue));
*err = error;
return NULL;
}
EXPORT_SYMBOL(__skb_recv_udp);
/*
* This should be easy, if there is something there we
* return it, otherwise we block.
*/
int udp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int noblock,
int flags, int *addr_len)
{
struct inet_sock *inet = inet_sk(sk);
DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
struct sk_buff *skb;
unsigned int ulen, copied;
int off, err, peeking = flags & MSG_PEEK;
int is_udplite = IS_UDPLITE(sk);
bool checksum_valid = false;
if (flags & MSG_ERRQUEUE)
return ip_recv_error(sk, msg, len, addr_len);
try_again:
off = sk_peek_offset(sk, flags);
skb = __skb_recv_udp(sk, flags, noblock, &off, &err);
if (!skb)
return err;
ulen = udp_skb_len(skb);
copied = len;
if (copied > ulen - off)
copied = ulen - off;
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 || peeking ||
(is_udplite && UDP_SKB_CB(skb)->partial_cov)) {
checksum_valid = udp_skb_csum_unnecessary(skb) ||
!__udp_lib_checksum_complete(skb);
if (!checksum_valid)
goto csum_copy_err;
}
if (checksum_valid || udp_skb_csum_unnecessary(skb)) {
if (udp_skb_is_linear(skb))
err = copy_linear_skb(skb, copied, off, &msg->msg_iter);
else
err = skb_copy_datagram_msg(skb, off, msg, copied);
} else {
err = skb_copy_and_csum_datagram_msg(skb, off, msg);
if (err == -EINVAL)
goto csum_copy_err;
}
if (unlikely(err)) {
if (!peeking) {
atomic_inc(&sk->sk_drops);
UDP_INC_STATS(sock_net(sk),
UDP_MIB_INERRORS, is_udplite);
}
kfree_skb(skb);
return err;
}
if (!peeking)
UDP_INC_STATS(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));
*addr_len = sizeof(*sin);
if (cgroup_bpf_enabled)
BPF_CGROUP_RUN_PROG_UDP4_RECVMSG_LOCK(sk,
(struct sockaddr *)sin);
}
if (udp_sk(sk)->gro_enabled)
udp_cmsg_recv(msg, sk, skb);
if (inet->cmsg_flags)
ip_cmsg_recv_offset(msg, sk, skb, sizeof(struct udphdr), off);
err = copied;
if (flags & MSG_TRUNC)
err = ulen;
skb_consume_udp(sk, skb, peeking ? -err : err);
return err;
csum_copy_err:
if (!__sk_queue_drop_skb(sk, &udp_sk(sk)->reader_queue, skb, flags,
udp_skb_destructor)) {
UDP_INC_STATS(sock_net(sk), UDP_MIB_CSUMERRORS, is_udplite);
UDP_INC_STATS(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
}
kfree_skb(skb);
/* starting over for a new packet, but check if we need to yield */
cond_resched();
msg->msg_flags &= ~MSG_TRUNC;
goto try_again;
}
int udp_pre_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
{
/* This check is replicated from __ip4_datagram_connect() and
* intended to prevent BPF program called below from accessing bytes
* that are out of the bound specified by user in addr_len.
*/
if (addr_len < sizeof(struct sockaddr_in))
return -EINVAL;
return BPF_CGROUP_RUN_PROG_INET4_CONNECT_LOCK(sk, uaddr);
}
EXPORT_SYMBOL(udp_pre_connect);
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);
int udp_disconnect(struct sock *sk, int flags)
{
lock_sock(sk);
__udp_disconnect(sk, flags);
release_sock(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 (rcu_access_pointer(sk->sk_reuseport_cb))
reuseport_detach_sock(sk);
if (sk_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_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 ||
rcu_access_pointer(sk->sk_reuseport_cb)) {
hslot = udp_hashslot(udptable, sock_net(sk),
udp_sk(sk)->udp_port_hash);
/* we must lock primary chain too */
spin_lock_bh(&hslot->lock);
if (rcu_access_pointer(sk->sk_reuseport_cb))
reuseport_detach_sock(sk);
if (hslot2 != nhslot2) {
spin_lock(&hslot2->lock);
hlist_del_init_rcu(&udp_sk(sk)->udp_portaddr_node);
hslot2->count--;
spin_unlock(&hslot2->lock);
spin_lock(&nhslot2->lock);
hlist_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);
void udp_v4_rehash(struct sock *sk)
{
u16 new_hash = ipv4_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);
sk_mark_napi_id(sk, skb);
sk_incoming_cpu_update(sk);
} else {
sk_mark_napi_id_once(sk, skb);
}
rc = __udp_enqueue_schedule_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(sock_net(sk), UDP_MIB_RCVBUFERRORS,
is_udplite);
UDP_INC_STATS(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.
*/
static int udp_queue_rcv_one_skb(struct sock *sk, struct sk_buff *skb)
{
struct udp_sock *up = udp_sk(sk);
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 (static_branch_unlikely(&udp_encap_needed_key) && 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 = READ_ONCE(up->encap_rcv);
if (encap_rcv) {
int ret;
/* Verify checksum before giving to encap */
if (udp_lib_checksum_complete(skb))
goto csum_error;
ret = encap_rcv(sk, skb);
if (ret <= 0) {
__UDP_INC_STATS(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 */
net_dbg_ratelimited("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) {
net_dbg_ratelimited("UDPLite: coverage %d too small, need min %d\n",
UDP_SKB_CB(skb)->cscov, up->pcrlen);
goto drop;
}
}
prefetch(&sk->sk_rmem_alloc);
if (rcu_access_pointer(sk->sk_filter) &&
udp_lib_checksum_complete(skb))
goto csum_error;
if (sk_filter_trim_cap(sk, skb, sizeof(struct udphdr)))
goto drop;
udp_csum_pull_header(skb);
ipv4_pktinfo_prepare(sk, skb);
return __udp_queue_rcv_skb(sk, skb);
csum_error:
__UDP_INC_STATS(sock_net(sk), UDP_MIB_CSUMERRORS, is_udplite);
drop:
__UDP_INC_STATS(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
atomic_inc(&sk->sk_drops);
kfree_skb(skb);
return -1;
}
static int udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
{
struct sk_buff *next, *segs;
int ret;
if (likely(!udp_unexpected_gso(sk, skb)))
return udp_queue_rcv_one_skb(sk, skb);
BUILD_BUG_ON(sizeof(struct udp_skb_cb) > SKB_SGO_CB_OFFSET);
__skb_push(skb, -skb_mac_offset(skb));
segs = udp_rcv_segment(sk, skb, true);
for (skb = segs; skb; skb = next) {
next = skb->next;
__skb_pull(skb, skb_transport_offset(skb));
ret = udp_queue_rcv_one_skb(sk, skb);
if (ret > 0)
ip_protocol_deliver_rcu(dev_net(skb->dev), skb, -ret);
}
return 0;
}
/* For TCP sockets, sk_rx_dst is protected by socket lock
* For UDP, we use xchg() to guard against concurrent changes.
*/
bool udp_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst)
{
struct dst_entry *old;
if (dst_hold_safe(dst)) {
old = xchg(&sk->sk_rx_dst, dst);
dst_release(old);
return old != dst;
}
return false;
}
EXPORT_SYMBOL(udp_sk_rx_dst_set);
/*
* 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,
int proto)
{
struct sock *sk, *first = NULL;
unsigned short hnum = ntohs(uh->dest);
struct udp_hslot *hslot = udp_hashslot(udptable, net, hnum);
unsigned int hash2 = 0, hash2_any = 0, use_hash2 = (hslot->count > 10);
unsigned int offset = offsetof(typeof(*sk), sk_node);
int dif = skb->dev->ifindex;
int sdif = inet_sdif(skb);
struct hlist_node *node;
struct sk_buff *nskb;
if (use_hash2) {
hash2_any = ipv4_portaddr_hash(net, htonl(INADDR_ANY), hnum) &
udptable->mask;
hash2 = ipv4_portaddr_hash(net, daddr, hnum) & udptable->mask;
start_lookup:
hslot = &udptable->hash2[hash2];
offset = offsetof(typeof(*sk), __sk_common.skc_portaddr_node);
}
sk_for_each_entry_offset_rcu(sk, node, &hslot->head, offset) {
if (!__udp_is_mcast_sock(net, sk, uh->dest, daddr,
uh->source, saddr, dif, sdif, hnum))
continue;
if (!first) {
first = sk;
continue;
}
nskb = skb_clone(skb, GFP_ATOMIC);
if (unlikely(!nskb)) {
atomic_inc(&sk->sk_drops);
__UDP_INC_STATS(net, UDP_MIB_RCVBUFERRORS,
IS_UDPLITE(sk));
__UDP_INC_STATS(net, UDP_MIB_INERRORS,
IS_UDPLITE(sk));
continue;
}
if (udp_queue_rcv_skb(sk, nskb) > 0)
consume_skb(nskb);
}
/* Also lookup *:port if we are using hash2 and haven't done so yet. */
if (use_hash2 && hash2 != hash2_any) {
hash2 = hash2_any;
goto start_lookup;
}
if (first) {
if (udp_queue_rcv_skb(first, skb) > 0)
consume_skb(skb);
} else {
kfree_skb(skb);
__UDP_INC_STATS(net, UDP_MIB_IGNOREDMULTI,
proto == IPPROTO_UDPLITE);
}
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)
{
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;
if (UDP_SKB_CB(skb)->partial_cov) {
skb->csum = inet_compute_pseudo(skb, proto);
return 0;
}
}
/* Note, we are only interested in != 0 or == 0, thus the
* force to int.
*/
err = (__force int)skb_checksum_init_zero_check(skb, proto, uh->check,
inet_compute_pseudo);
if (err)
return err;
if (skb->ip_summed == CHECKSUM_COMPLETE && !skb->csum_valid) {
/* If SW calculated the value, we know it's bad */
if (skb->csum_complete_sw)
return 1;
/* HW says the value is bad. Let's validate that.
* skb->csum is no longer the full packet checksum,
* so don't treat it as such.
*/
skb_checksum_complete_unset(skb);
}
return 0;
}
/* wrapper for udp_queue_rcv_skb tacking care of csum conversion and
* return code conversion for ip layer consumption
*/
static int udp_unicast_rcv_skb(struct sock *sk, struct sk_buff *skb,
struct udphdr *uh)
{
int ret;
if (inet_get_convert_csum(sk) && uh->check && !IS_UDPLITE(sk))
skb_checksum_try_convert(skb, IPPROTO_UDP, uh->check,
inet_compute_pseudo);
ret = udp_queue_rcv_skb(sk, skb);
/* 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;
}
/*
* 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;
sk = skb_steal_sock(skb);
if (sk) {
struct dst_entry *dst = skb_dst(skb);
int ret;
if (unlikely(sk->sk_rx_dst != dst))
udp_sk_rx_dst_set(sk, dst);
ret = udp_unicast_rcv_skb(sk, skb, uh);
sock_put(sk);
return ret;
}
if (rt->rt_flags & (RTCF_BROADCAST|RTCF_MULTICAST))
return __udp4_lib_mcast_deliver(net, skb, uh,
saddr, daddr, udptable, proto);
sk = __udp4_lib_lookup_skb(skb, uh->source, uh->dest, udptable);
if (sk)
return udp_unicast_rcv_skb(sk, skb, uh);
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(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:
net_dbg_ratelimited("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).
*/
net_dbg_ratelimited("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);
__UDP_INC_STATS(net, UDP_MIB_CSUMERRORS, proto == IPPROTO_UDPLITE);
drop:
__UDP_INC_STATS(net, UDP_MIB_INERRORS, proto == IPPROTO_UDPLITE);
kfree_skb(skb);
return 0;
}
/* We can only early demux multicast if there is a single matching socket.
* If more than one socket found returns NULL
*/
static struct sock *__udp4_lib_mcast_demux_lookup(struct net *net,
__be16 loc_port, __be32 loc_addr,
__be16 rmt_port, __be32 rmt_addr,
int dif, int sdif)
{
struct sock *sk, *result;
unsigned short hnum = ntohs(loc_port);
unsigned int slot = udp_hashfn(net, hnum, udp_table.mask);
struct udp_hslot *hslot = &udp_table.hash[slot];
/* Do not bother scanning a too big list */
if (hslot->count > 10)
return NULL;
result = NULL;
sk_for_each_rcu(sk, &hslot->head) {
if (__udp_is_mcast_sock(net, sk, loc_port, loc_addr,
rmt_port, rmt_addr, dif, sdif, hnum)) {
if (result)
return NULL;
result = sk;
}
}
return result;
}
/* For unicast we should only early demux connected sockets or we can
* break forwarding setups. The chains here can be long so only check
* if the first socket is an exact match and if not move on.
*/
static struct sock *__udp4_lib_demux_lookup(struct net *net,
__be16 loc_port, __be32 loc_addr,
__be16 rmt_port, __be32 rmt_addr,
int dif, int sdif)
{
unsigned short hnum = ntohs(loc_port);
unsigned int hash2 = ipv4_portaddr_hash(net, loc_addr, hnum);
unsigned int slot2 = hash2 & udp_table.mask;
struct udp_hslot *hslot2 = &udp_table.hash2[slot2];
INET_ADDR_COOKIE(acookie, rmt_addr, loc_addr);
const __portpair ports = INET_COMBINED_PORTS(rmt_port, hnum);
struct sock *sk;
udp_portaddr_for_each_entry_rcu(sk, &hslot2->head) {
if (INET_MATCH(sk, net, acookie, rmt_addr,
loc_addr, ports, dif, sdif))
return sk;
/* Only check first socket in chain */
break;
}
return NULL;
}
int udp_v4_early_demux(struct sk_buff *skb)
{
struct net *net = dev_net(skb->dev);
struct in_device *in_dev = NULL;
const struct iphdr *iph;
const struct udphdr *uh;
struct sock *sk = NULL;
struct dst_entry *dst;
int dif = skb->dev->ifindex;
int sdif = inet_sdif(skb);
int ours;
/* validate the packet */
if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct udphdr)))
return 0;
iph = ip_hdr(skb);
uh = udp_hdr(skb);
if (skb->pkt_type == PACKET_MULTICAST) {
in_dev = __in_dev_get_rcu(skb->dev);
if (!in_dev)
return 0;
ours = ip_check_mc_rcu(in_dev, iph->daddr, iph->saddr,
iph->protocol);
if (!ours)
return 0;
sk = __udp4_lib_mcast_demux_lookup(net, uh->dest, iph->daddr,
uh->source, iph->saddr,
dif, sdif);
} else if (skb->pkt_type == PACKET_HOST) {
sk = __udp4_lib_demux_lookup(net, uh->dest, iph->daddr,
uh->source, iph->saddr, dif, sdif);
}
if (!sk || !refcount_inc_not_zero(&sk->sk_refcnt))
return 0;
skb->sk = sk;
skb->destructor = sock_efree;
dst = READ_ONCE(sk->sk_rx_dst);
if (dst)
dst = dst_check(dst, 0);
if (dst) {
u32 itag = 0;
/* set noref for now.
* any place which wants to hold dst has to call
* dst_hold_safe()
*/
skb_dst_set_noref(skb, dst);
/* for unconnected multicast sockets we need to validate
* the source on each packet
*/
if (!inet_sk(sk)->inet_daddr && in_dev)
return ip_mc_validate_source(skb, iph->daddr,
iph->saddr, iph->tos,
skb->dev, in_dev, &itag);
}
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)
{
struct udp_sock *up = udp_sk(sk);
bool slow = lock_sock_fast(sk);
udp_flush_pending_frames(sk);
unlock_sock_fast(sk, slow);
if (static_branch_unlikely(&udp_encap_needed_key)) {
if (up->encap_type) {
void (*encap_destroy)(struct sock *sk);
encap_destroy = READ_ONCE(up->encap_destroy);
if (encap_destroy)
encap_destroy(sk);
}
if (up->encap_enabled)
static_branch_dec(&udp_encap_needed_key);
}
}
/*
* 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, valbool;
int err = 0;
int is_udplite = IS_UDPLITE(sk);
if (optlen < sizeof(int))
return -EINVAL;
if (get_user(val, (int __user *)optval))
return -EFAULT;
valbool = val ? 1 : 0;
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;
lock_sock(sk);
udp_tunnel_encap_enable(sk->sk_socket);
release_sock(sk);
break;
default:
err = -ENOPROTOOPT;
break;
}
break;
case UDP_NO_CHECK6_TX:
up->no_check6_tx = valbool;
break;
case UDP_NO_CHECK6_RX:
up->no_check6_rx = valbool;
break;
case UDP_SEGMENT:
if (val < 0 || val > USHRT_MAX)
return -EINVAL;
up->gso_size = val;
break;
case UDP_GRO:
lock_sock(sk);
if (valbool)
udp_tunnel_encap_enable(sk->sk_socket);
up->gro_enabled = valbool;
release_sock(sk);
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;
case UDP_NO_CHECK6_TX:
val = up->no_check6_tx;
break;
case UDP_NO_CHECK6_RX:
val = up->no_check6_rx;
break;
case UDP_SEGMENT:
val = up->gso_size;
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.
*/
__poll_t udp_poll(struct file *file, struct socket *sock, poll_table *wait)
{
__poll_t mask = datagram_poll(file, sock, wait);
struct sock *sk = sock->sk;
if (!skb_queue_empty(&udp_sk(sk)->reader_queue))
mask |= EPOLLIN | EPOLLRDNORM;
/* Check for false positives due to checksum errors */
if ((mask & EPOLLRDNORM) && !(file->f_flags & O_NONBLOCK) &&
!(sk->sk_shutdown & RCV_SHUTDOWN) && first_packet_length(sk) == -1)
mask &= ~(EPOLLIN | EPOLLRDNORM);
return mask;
}
EXPORT_SYMBOL(udp_poll);
int udp_abort(struct sock *sk, int err)
{
lock_sock(sk);
sk->sk_err = err;
sk->sk_error_report(sk);
__udp_disconnect(sk, 0);
release_sock(sk);
return 0;
}
EXPORT_SYMBOL_GPL(udp_abort);
struct proto udp_prot = {
.name = "UDP",
.owner = THIS_MODULE,
.close = udp_lib_close,
.pre_connect = udp_pre_connect,
.connect = ip4_datagram_connect,
.disconnect = udp_disconnect,
.ioctl = udp_ioctl,
.init = udp_init_sock,
.destroy = udp_destroy_sock,
.setsockopt = udp_setsockopt,
.getsockopt = udp_getsockopt,
.sendmsg = udp_sendmsg,
.recvmsg = udp_recvmsg,
.sendpage = udp_sendpage,
.release_cb = ip4_datagram_release_cb,
.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_offset = offsetof(struct net, ipv4.sysctl_udp_wmem_min),
.sysctl_rmem_offset = offsetof(struct net, ipv4.sysctl_udp_rmem_min),
.obj_size = sizeof(struct udp_sock),
.h.udp_table = &udp_table,
#ifdef CONFIG_COMPAT
.compat_setsockopt = compat_udp_setsockopt,
.compat_getsockopt = compat_udp_getsockopt,
#endif
.diag_destroy = udp_abort,
};
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_seq_afinfo *afinfo = PDE_DATA(file_inode(seq->file));
struct udp_iter_state *state = seq->private;
struct net *net = seq_file_net(seq);
for (state->bucket = start; state->bucket <= afinfo->udp_table->mask;
++state->bucket) {
struct udp_hslot *hslot = &afinfo->udp_table->hash[state->bucket];
if (hlist_empty(&hslot->head))
continue;
spin_lock_bh(&hslot->lock);
sk_for_each(sk, &hslot->head) {
if (!net_eq(sock_net(sk), net))
continue;
if (sk->sk_family == afinfo->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_seq_afinfo *afinfo = PDE_DATA(file_inode(seq->file));
struct udp_iter_state *state = seq->private;
struct net *net = seq_file_net(seq);
do {
sk = sk_next(sk);
} while (sk && (!net_eq(sock_net(sk), net) || sk->sk_family != afinfo->family));
if (!sk) {
if (state->bucket <= afinfo->udp_table->mask)
spin_unlock_bh(&afinfo->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;
}
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;
}
EXPORT_SYMBOL(udp_seq_start);
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;
}
EXPORT_SYMBOL(udp_seq_next);
void udp_seq_stop(struct seq_file *seq, void *v)
{
struct udp_seq_afinfo *afinfo = PDE_DATA(file_inode(seq->file));
struct udp_iter_state *state = seq->private;
if (state->bucket <= afinfo->udp_table->mask)
spin_unlock_bh(&afinfo->udp_table->hash[state->bucket].lock);
}
EXPORT_SYMBOL(udp_seq_stop);
/* ------------------------------------------------------------------------ */
static void udp4_format_sock(struct sock *sp, struct seq_file *f,
int bucket)
{
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 %5u %8d %lu %d %pK %u",
bucket, src, srcp, dest, destp, sp->sk_state,
sk_wmem_alloc_get(sp),
udp_rqueue_get(sp),
0, 0L, 0,
from_kuid_munged(seq_user_ns(f), sock_i_uid(sp)),
0, sock_i_ino(sp),
refcount_read(&sp->sk_refcnt), sp,
atomic_read(&sp->sk_drops));
}
int udp4_seq_show(struct seq_file *seq, void *v)
{
seq_setwidth(seq, 127);
if (v == SEQ_START_TOKEN)
seq_puts(seq, " 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;
udp4_format_sock(v, seq, state->bucket);
}
seq_pad(seq, '\n');
return 0;
}
const struct seq_operations udp_seq_ops = {
.start = udp_seq_start,
.next = udp_seq_next,
.stop = udp_seq_stop,
.show = udp4_seq_show,
};
EXPORT_SYMBOL(udp_seq_ops);
static struct udp_seq_afinfo udp4_seq_afinfo = {
.family = AF_INET,
.udp_table = &udp_table,
};
static int __net_init udp4_proc_init_net(struct net *net)
{
if (!proc_create_net_data("udp", 0444, net->proc_net, &udp_seq_ops,
sizeof(struct udp_iter_state), &udp4_seq_afinfo))
return -ENOMEM;
return 0;
}
static void __net_exit udp4_proc_exit_net(struct net *net)
{
remove_proc_entry("udp", net->proc_net);
}
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)
{
ssize_t ret;
if (!str)
return 0;
ret = kstrtoul(str, 0, &uhash_entries);
if (ret)
return 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;
table->hash = alloc_large_system_hash(name,
2 * sizeof(struct udp_hslot),
uhash_entries,
21, /* one slot per 2 MB */
0,
&table->log,
&table->mask,
UDP_HTABLE_SIZE_MIN,
64 * 1024);
table->hash2 = table->hash + (table->mask + 1);
for (i = 0; i <= table->mask; i++) {
INIT_HLIST_HEAD(&table->hash[i].head);
table->hash[i].count = 0;
spin_lock_init(&table->hash[i].lock);
}
for (i = 0; i <= table->mask; i++) {
INIT_HLIST_HEAD(&table->hash2[i].head);
table->hash2[i].count = 0;
spin_lock_init(&table->hash2[i].lock);
}
}
u32 udp_flow_hashrnd(void)
{
static u32 hashrnd __read_mostly;
net_get_random_once(&hashrnd, sizeof(hashrnd));
return hashrnd;
}
EXPORT_SYMBOL(udp_flow_hashrnd);
static void __udp_sysctl_init(struct net *net)
{
net->ipv4.sysctl_udp_rmem_min = SK_MEM_QUANTUM;
net->ipv4.sysctl_udp_wmem_min = SK_MEM_QUANTUM;
#ifdef CONFIG_NET_L3_MASTER_DEV
net->ipv4.sysctl_udp_l3mdev_accept = 0;
#endif
}
static int __net_init udp_sysctl_init(struct net *net)
{
__udp_sysctl_init(net);
return 0;
}
static struct pernet_operations __net_initdata udp_sysctl_ops = {
.init = udp_sysctl_init,
};
void __init udp_init(void)
{
unsigned long limit;
unsigned int i;
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;
__udp_sysctl_init(&init_net);
/* 16 spinlocks per cpu */
udp_busylocks_log = ilog2(nr_cpu_ids) + 4;
udp_busylocks = kmalloc(sizeof(spinlock_t) << udp_busylocks_log,
GFP_KERNEL);
if (!udp_busylocks)
panic("UDP: failed to alloc udp_busylocks\n");
for (i = 0; i < (1U << udp_busylocks_log); i++)
spin_lock_init(udp_busylocks + i);
if (register_pernet_subsys(&udp_sysctl_ops))
panic("UDP: failed to init sysctl parameters.\n");
}
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