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udp.c
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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* UDP over IPv6
* Linux INET6 implementation
*
* Authors:
* Pedro Roque <[email protected]>
*
* Based on linux/ipv4/udp.c
*
* Fixes:
* Hideaki YOSHIFUJI : sin6_scope_id support
* 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.
* Kazunori MIYAZAWA @USAGI: change process style to use ip6_append_data
* YOSHIFUJI Hideaki @USAGI: convert /proc/net/udp6 to seq_file.
*/
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <linux/in6.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <linux/ipv6.h>
#include <linux/icmpv6.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/indirect_call_wrapper.h>
#include <net/addrconf.h>
#include <net/ndisc.h>
#include <net/protocol.h>
#include <net/transp_v6.h>
#include <net/ip6_route.h>
#include <net/raw.h>
#include <net/tcp_states.h>
#include <net/ip6_checksum.h>
#include <net/ip6_tunnel.h>
#include <net/xfrm.h>
#include <net/inet_hashtables.h>
#include <net/inet6_hashtables.h>
#include <net/busy_poll.h>
#include <net/sock_reuseport.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <trace/events/skb.h>
#include "udp_impl.h"
static u32 udp6_ehashfn(const struct net *net,
const struct in6_addr *laddr,
const u16 lport,
const struct in6_addr *faddr,
const __be16 fport)
{
static u32 udp6_ehash_secret __read_mostly;
static u32 udp_ipv6_hash_secret __read_mostly;
u32 lhash, fhash;
net_get_random_once(&udp6_ehash_secret,
sizeof(udp6_ehash_secret));
net_get_random_once(&udp_ipv6_hash_secret,
sizeof(udp_ipv6_hash_secret));
lhash = (__force u32)laddr->s6_addr32[3];
fhash = __ipv6_addr_jhash(faddr, udp_ipv6_hash_secret);
return __inet6_ehashfn(lhash, lport, fhash, fport,
udp_ipv6_hash_secret + net_hash_mix(net));
}
int udp_v6_get_port(struct sock *sk, unsigned short snum)
{
unsigned int hash2_nulladdr =
ipv6_portaddr_hash(sock_net(sk), &in6addr_any, snum);
unsigned int hash2_partial =
ipv6_portaddr_hash(sock_net(sk), &sk->sk_v6_rcv_saddr, 0);
/* precompute partial secondary hash */
udp_sk(sk)->udp_portaddr_hash = hash2_partial;
return udp_lib_get_port(sk, snum, hash2_nulladdr);
}
void udp_v6_rehash(struct sock *sk)
{
u16 new_hash = ipv6_portaddr_hash(sock_net(sk),
&sk->sk_v6_rcv_saddr,
inet_sk(sk)->inet_num);
udp_lib_rehash(sk, new_hash);
}
static int compute_score(struct sock *sk, struct net *net,
const struct in6_addr *saddr, __be16 sport,
const struct in6_addr *daddr, unsigned short hnum,
int dif, int sdif)
{
int score;
struct inet_sock *inet;
bool dev_match;
if (!net_eq(sock_net(sk), net) ||
udp_sk(sk)->udp_port_hash != hnum ||
sk->sk_family != PF_INET6)
return -1;
if (!ipv6_addr_equal(&sk->sk_v6_rcv_saddr, daddr))
return -1;
score = 0;
inet = inet_sk(sk);
if (inet->inet_dport) {
if (inet->inet_dport != sport)
return -1;
score++;
}
if (!ipv6_addr_any(&sk->sk_v6_daddr)) {
if (!ipv6_addr_equal(&sk->sk_v6_daddr, saddr))
return -1;
score++;
}
dev_match = udp_sk_bound_dev_eq(net, sk->sk_bound_dev_if, dif, sdif);
if (!dev_match)
return -1;
score++;
if (READ_ONCE(sk->sk_incoming_cpu) == raw_smp_processor_id())
score++;
return score;
}
/* called with rcu_read_lock() */
static struct sock *udp6_lib_lookup2(struct net *net,
const struct in6_addr *saddr, __be16 sport,
const struct in6_addr *daddr, unsigned int hnum,
int dif, int sdif, struct udp_hslot *hslot2,
struct sk_buff *skb)
{
struct sock *sk, *result;
int score, badness;
u32 hash = 0;
result = NULL;
badness = -1;
udp_portaddr_for_each_entry_rcu(sk, &hslot2->head) {
score = compute_score(sk, net, saddr, sport,
daddr, hnum, dif, sdif);
if (score > badness) {
if (sk->sk_reuseport &&
sk->sk_state != TCP_ESTABLISHED) {
hash = udp6_ehashfn(net, daddr, hnum,
saddr, sport);
result = reuseport_select_sock(sk, hash, skb,
sizeof(struct udphdr));
if (result && !reuseport_has_conns(sk, false))
return result;
}
result = sk;
badness = score;
}
}
return result;
}
/* rcu_read_lock() must be held */
struct sock *__udp6_lib_lookup(struct net *net,
const struct in6_addr *saddr, __be16 sport,
const struct in6_addr *daddr, __be16 dport,
int dif, int sdif, struct udp_table *udptable,
struct sk_buff *skb)
{
unsigned short hnum = ntohs(dport);
unsigned int hash2, slot2;
struct udp_hslot *hslot2;
struct sock *result;
hash2 = ipv6_portaddr_hash(net, daddr, hnum);
slot2 = hash2 & udptable->mask;
hslot2 = &udptable->hash2[slot2];
result = udp6_lib_lookup2(net, saddr, sport,
daddr, hnum, dif, sdif,
hslot2, skb);
if (!result) {
hash2 = ipv6_portaddr_hash(net, &in6addr_any, hnum);
slot2 = hash2 & udptable->mask;
hslot2 = &udptable->hash2[slot2];
result = udp6_lib_lookup2(net, saddr, sport,
&in6addr_any, hnum, dif, sdif,
hslot2, skb);
}
if (IS_ERR(result))
return NULL;
return result;
}
EXPORT_SYMBOL_GPL(__udp6_lib_lookup);
static struct sock *__udp6_lib_lookup_skb(struct sk_buff *skb,
__be16 sport, __be16 dport,
struct udp_table *udptable)
{
const struct ipv6hdr *iph = ipv6_hdr(skb);
return __udp6_lib_lookup(dev_net(skb->dev), &iph->saddr, sport,
&iph->daddr, dport, inet6_iif(skb),
inet6_sdif(skb), udptable, skb);
}
struct sock *udp6_lib_lookup_skb(struct sk_buff *skb,
__be16 sport, __be16 dport)
{
const struct ipv6hdr *iph = ipv6_hdr(skb);
return __udp6_lib_lookup(dev_net(skb->dev), &iph->saddr, sport,
&iph->daddr, dport, inet6_iif(skb),
inet6_sdif(skb), &udp_table, NULL);
}
EXPORT_SYMBOL_GPL(udp6_lib_lookup_skb);
/* Must be called under rcu_read_lock().
* Does increment socket refcount.
*/
#if IS_ENABLED(CONFIG_NF_TPROXY_IPV6) || IS_ENABLED(CONFIG_NF_SOCKET_IPV6)
struct sock *udp6_lib_lookup(struct net *net, const struct in6_addr *saddr, __be16 sport,
const struct in6_addr *daddr, __be16 dport, int dif)
{
struct sock *sk;
sk = __udp6_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(udp6_lib_lookup);
#endif
/* do not use the scratch area len for jumbogram: their length execeeds the
* scratch area space; note that the IP6CB flags is still in the first
* cacheline, so checking for jumbograms is cheap
*/
static int udp6_skb_len(struct sk_buff *skb)
{
return unlikely(inet6_is_jumbogram(skb)) ? skb->len : udp_skb_len(skb);
}
/*
* This should be easy, if there is something there we
* return it, otherwise we block.
*/
int udpv6_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
int noblock, int flags, int *addr_len)
{
struct ipv6_pinfo *np = inet6_sk(sk);
struct inet_sock *inet = inet_sk(sk);
struct sk_buff *skb;
unsigned int ulen, copied;
int off, err, peeking = flags & MSG_PEEK;
int is_udplite = IS_UDPLITE(sk);
struct udp_mib __percpu *mib;
bool checksum_valid = false;
int is_udp4;
if (flags & MSG_ERRQUEUE)
return ipv6_recv_error(sk, msg, len, addr_len);
if (np->rxpmtu && np->rxopt.bits.rxpmtu)
return ipv6_recv_rxpmtu(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 = udp6_skb_len(skb);
copied = len;
if (copied > ulen - off)
copied = ulen - off;
else if (copied < ulen)
msg->msg_flags |= MSG_TRUNC;
is_udp4 = (skb->protocol == htons(ETH_P_IP));
mib = __UDPX_MIB(sk, is_udp4);
/*
* 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);
SNMP_INC_STATS(mib, UDP_MIB_INERRORS);
}
kfree_skb(skb);
return err;
}
if (!peeking)
SNMP_INC_STATS(mib, UDP_MIB_INDATAGRAMS);
sock_recv_ts_and_drops(msg, sk, skb);
/* Copy the address. */
if (msg->msg_name) {
DECLARE_SOCKADDR(struct sockaddr_in6 *, sin6, msg->msg_name);
sin6->sin6_family = AF_INET6;
sin6->sin6_port = udp_hdr(skb)->source;
sin6->sin6_flowinfo = 0;
if (is_udp4) {
ipv6_addr_set_v4mapped(ip_hdr(skb)->saddr,
&sin6->sin6_addr);
sin6->sin6_scope_id = 0;
} else {
sin6->sin6_addr = ipv6_hdr(skb)->saddr;
sin6->sin6_scope_id =
ipv6_iface_scope_id(&sin6->sin6_addr,
inet6_iif(skb));
}
*addr_len = sizeof(*sin6);
if (cgroup_bpf_enabled)
BPF_CGROUP_RUN_PROG_UDP6_RECVMSG_LOCK(sk,
(struct sockaddr *)sin6);
}
if (udp_sk(sk)->gro_enabled)
udp_cmsg_recv(msg, sk, skb);
if (np->rxopt.all)
ip6_datagram_recv_common_ctl(sk, msg, skb);
if (is_udp4) {
if (inet->cmsg_flags)
ip_cmsg_recv_offset(msg, sk, skb,
sizeof(struct udphdr), off);
} else {
if (np->rxopt.all)
ip6_datagram_recv_specific_ctl(sk, msg, skb);
}
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)) {
SNMP_INC_STATS(mib, UDP_MIB_CSUMERRORS);
SNMP_INC_STATS(mib, UDP_MIB_INERRORS);
}
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;
}
DEFINE_STATIC_KEY_FALSE(udpv6_encap_needed_key);
void udpv6_encap_enable(void)
{
static_branch_inc(&udpv6_encap_needed_key);
}
EXPORT_SYMBOL(udpv6_encap_enable);
/* Handler for tunnels with arbitrary destination ports: no socket lookup, go
* through error handlers in encapsulations looking for a match.
*/
static int __udp6_lib_err_encap_no_sk(struct sk_buff *skb,
struct inet6_skb_parm *opt,
u8 type, u8 code, int offset, __be32 info)
{
int i;
for (i = 0; i < MAX_IPTUN_ENCAP_OPS; i++) {
int (*handler)(struct sk_buff *skb, struct inet6_skb_parm *opt,
u8 type, u8 code, int offset, __be32 info);
const struct ip6_tnl_encap_ops *encap;
encap = rcu_dereference(ip6tun_encaps[i]);
if (!encap)
continue;
handler = encap->err_handler;
if (handler && !handler(skb, opt, type, code, offset, 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 *__udp6_lib_err_encap(struct net *net,
const struct ipv6hdr *hdr, int offset,
struct udphdr *uh,
struct udp_table *udptable,
struct sk_buff *skb,
struct inet6_skb_parm *opt,
u8 type, u8 code, __be32 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 IPv6 header inside ICMP */
skb_reset_network_header(skb);
/* Transport header needs to point to the UDP header */
skb_set_transport_header(skb, offset);
sk = __udp6_lib_lookup(net, &hdr->daddr, uh->source,
&hdr->saddr, uh->dest,
inet6_iif(skb), 0, udptable, skb);
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(__udp6_lib_err_encap_no_sk(skb, opt, type, code,
offset, info));
}
skb_set_transport_header(skb, transport_offset);
skb_set_network_header(skb, network_offset);
return sk;
}
int __udp6_lib_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
u8 type, u8 code, int offset, __be32 info,
struct udp_table *udptable)
{
struct ipv6_pinfo *np;
const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data;
const struct in6_addr *saddr = &hdr->saddr;
const struct in6_addr *daddr = &hdr->daddr;
struct udphdr *uh = (struct udphdr *)(skb->data+offset);
bool tunnel = false;
struct sock *sk;
int harderr;
int err;
struct net *net = dev_net(skb->dev);
sk = __udp6_lib_lookup(net, daddr, uh->dest, saddr, uh->source,
inet6_iif(skb), inet6_sdif(skb), udptable, NULL);
if (!sk) {
/* No socket for error: try tunnels before discarding */
sk = ERR_PTR(-ENOENT);
if (static_branch_unlikely(&udpv6_encap_needed_key)) {
sk = __udp6_lib_err_encap(net, hdr, offset, uh,
udptable, skb,
opt, type, code, info);
if (!sk)
return 0;
}
if (IS_ERR(sk)) {
__ICMP6_INC_STATS(net, __in6_dev_get(skb->dev),
ICMP6_MIB_INERRORS);
return PTR_ERR(sk);
}
tunnel = true;
}
harderr = icmpv6_err_convert(type, code, &err);
np = inet6_sk(sk);
if (type == ICMPV6_PKT_TOOBIG) {
if (!ip6_sk_accept_pmtu(sk))
goto out;
ip6_sk_update_pmtu(skb, sk, info);
if (np->pmtudisc != IPV6_PMTUDISC_DONT)
harderr = 1;
}
if (type == NDISC_REDIRECT) {
if (tunnel) {
ip6_redirect(skb, sock_net(sk), inet6_iif(skb),
sk->sk_mark, sk->sk_uid);
} else {
ip6_sk_redirect(skb, sk);
}
goto out;
}
/* Tunnels don't have an application socket: don't pass errors back */
if (tunnel)
goto out;
if (!np->recverr) {
if (!harderr || sk->sk_state != TCP_ESTABLISHED)
goto out;
} else {
ipv6_icmp_error(sk, skb, err, uh->dest, ntohl(info), (u8 *)(uh+1));
}
sk->sk_err = err;
sk->sk_error_report(sk);
out:
return 0;
}
static int __udpv6_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
{
int rc;
if (!ipv6_addr_any(&sk->sk_v6_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)
UDP6_INC_STATS(sock_net(sk),
UDP_MIB_RCVBUFERRORS, is_udplite);
UDP6_INC_STATS(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
kfree_skb(skb);
return -1;
}
return 0;
}
static __inline__ int udpv6_err(struct sk_buff *skb,
struct inet6_skb_parm *opt, u8 type,
u8 code, int offset, __be32 info)
{
return __udp6_lib_err(skb, opt, type, code, offset, info, &udp_table);
}
static int udpv6_queue_rcv_one_skb(struct sock *sk, struct sk_buff *skb)
{
struct udp_sock *up = udp_sk(sk);
int is_udplite = IS_UDPLITE(sk);
if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
goto drop;
if (static_branch_unlikely(&udpv6_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 (see net/ipv4/udp.c).
*/
if ((is_udplite & UDPLITE_RECV_CC) && UDP_SKB_CB(skb)->partial_cov) {
if (up->pcrlen == 0) { /* full coverage was set */
net_dbg_ratelimited("UDPLITE6: partial coverage %d while full coverage %d requested\n",
UDP_SKB_CB(skb)->cscov, skb->len);
goto drop;
}
if (UDP_SKB_CB(skb)->cscov < up->pcrlen) {
net_dbg_ratelimited("UDPLITE6: 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);
skb_dst_drop(skb);
return __udpv6_queue_rcv_skb(sk, skb);
csum_error:
__UDP6_INC_STATS(sock_net(sk), UDP_MIB_CSUMERRORS, is_udplite);
drop:
__UDP6_INC_STATS(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
atomic_inc(&sk->sk_drops);
kfree_skb(skb);
return -1;
}
static int udpv6_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 udpv6_queue_rcv_one_skb(sk, skb);
__skb_push(skb, -skb_mac_offset(skb));
segs = udp_rcv_segment(sk, skb, false);
for (skb = segs; skb; skb = next) {
next = skb->next;
__skb_pull(skb, skb_transport_offset(skb));
ret = udpv6_queue_rcv_one_skb(sk, skb);
if (ret > 0)
ip6_protocol_deliver_rcu(dev_net(skb->dev), skb, ret,
true);
}
return 0;
}
static bool __udp_v6_is_mcast_sock(struct net *net, struct sock *sk,
__be16 loc_port, const struct in6_addr *loc_addr,
__be16 rmt_port, const struct in6_addr *rmt_addr,
int dif, int sdif, unsigned short hnum)
{
struct inet_sock *inet = inet_sk(sk);
if (!net_eq(sock_net(sk), net))
return false;
if (udp_sk(sk)->udp_port_hash != hnum ||
sk->sk_family != PF_INET6 ||
(inet->inet_dport && inet->inet_dport != rmt_port) ||
(!ipv6_addr_any(&sk->sk_v6_daddr) &&
!ipv6_addr_equal(&sk->sk_v6_daddr, rmt_addr)) ||
!udp_sk_bound_dev_eq(net, sk->sk_bound_dev_if, dif, sdif) ||
(!ipv6_addr_any(&sk->sk_v6_rcv_saddr) &&
!ipv6_addr_equal(&sk->sk_v6_rcv_saddr, loc_addr)))
return false;
if (!inet6_mc_check(sk, loc_addr, rmt_addr))
return false;
return true;
}
static void udp6_csum_zero_error(struct sk_buff *skb)
{
/* RFC 2460 section 8.1 says that we SHOULD log
* this error. Well, it is reasonable.
*/
net_dbg_ratelimited("IPv6: udp checksum is 0 for [%pI6c]:%u->[%pI6c]:%u\n",
&ipv6_hdr(skb)->saddr, ntohs(udp_hdr(skb)->source),
&ipv6_hdr(skb)->daddr, ntohs(udp_hdr(skb)->dest));
}
/*
* Note: called only from the BH handler context,
* so we don't need to lock the hashes.
*/
static int __udp6_lib_mcast_deliver(struct net *net, struct sk_buff *skb,
const struct in6_addr *saddr, const struct in6_addr *daddr,
struct udp_table *udptable, int proto)
{
struct sock *sk, *first = NULL;
const struct udphdr *uh = udp_hdr(skb);
unsigned short hnum = ntohs(uh->dest);
struct udp_hslot *hslot = udp_hashslot(udptable, net, hnum);
unsigned int offset = offsetof(typeof(*sk), sk_node);
unsigned int hash2 = 0, hash2_any = 0, use_hash2 = (hslot->count > 10);
int dif = inet6_iif(skb);
int sdif = inet6_sdif(skb);
struct hlist_node *node;
struct sk_buff *nskb;
if (use_hash2) {
hash2_any = ipv6_portaddr_hash(net, &in6addr_any, hnum) &
udptable->mask;
hash2 = ipv6_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_v6_is_mcast_sock(net, sk, uh->dest, daddr,
uh->source, saddr, dif, sdif,
hnum))
continue;
/* If zero checksum and no_check is not on for
* the socket then skip it.
*/
if (!uh->check && !udp_sk(sk)->no_check6_rx)
continue;
if (!first) {
first = sk;
continue;
}
nskb = skb_clone(skb, GFP_ATOMIC);
if (unlikely(!nskb)) {
atomic_inc(&sk->sk_drops);
__UDP6_INC_STATS(net, UDP_MIB_RCVBUFERRORS,
IS_UDPLITE(sk));
__UDP6_INC_STATS(net, UDP_MIB_INERRORS,
IS_UDPLITE(sk));
continue;
}
if (udpv6_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 (udpv6_queue_rcv_skb(first, skb) > 0)
consume_skb(skb);
} else {
kfree_skb(skb);
__UDP6_INC_STATS(net, UDP_MIB_IGNOREDMULTI,
proto == IPPROTO_UDPLITE);
}
return 0;
}
static void udp6_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst)
{
if (udp_sk_rx_dst_set(sk, dst)) {
const struct rt6_info *rt = (const struct rt6_info *)dst;
inet6_sk(sk)->rx_dst_cookie = rt6_get_cookie(rt);
}
}
/* wrapper for udp_queue_rcv_skb tacking care of csum conversion and
* return code conversion for ip layer consumption
*/
static int udp6_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, ip6_compute_pseudo);
ret = udpv6_queue_rcv_skb(sk, skb);
/* a return value > 0 means to resubmit the input */
if (ret > 0)
return ret;
return 0;
}
int __udp6_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
int proto)
{
const struct in6_addr *saddr, *daddr;
struct net *net = dev_net(skb->dev);
struct udphdr *uh;
struct sock *sk;
u32 ulen = 0;
if (!pskb_may_pull(skb, sizeof(struct udphdr)))
goto discard;
saddr = &ipv6_hdr(skb)->saddr;
daddr = &ipv6_hdr(skb)->daddr;
uh = udp_hdr(skb);
ulen = ntohs(uh->len);
if (ulen > skb->len)
goto short_packet;
if (proto == IPPROTO_UDP) {
/* UDP validates ulen. */
/* Check for jumbo payload */
if (ulen == 0)
ulen = skb->len;
if (ulen < sizeof(*uh))
goto short_packet;
if (ulen < skb->len) {
if (pskb_trim_rcsum(skb, ulen))
goto short_packet;
saddr = &ipv6_hdr(skb)->saddr;
daddr = &ipv6_hdr(skb)->daddr;
uh = udp_hdr(skb);
}
}
if (udp6_csum_init(skb, uh, proto))
goto csum_error;
/* Check if the socket is already available, e.g. due to early demux */
sk = skb_steal_sock(skb);
if (sk) {
struct dst_entry *dst = skb_dst(skb);
int ret;
if (unlikely(sk->sk_rx_dst != dst))
udp6_sk_rx_dst_set(sk, dst);
if (!uh->check && !udp_sk(sk)->no_check6_rx) {
sock_put(sk);
goto report_csum_error;
}
ret = udp6_unicast_rcv_skb(sk, skb, uh);
sock_put(sk);
return ret;
}
/*
* Multicast receive code
*/
if (ipv6_addr_is_multicast(daddr))
return __udp6_lib_mcast_deliver(net, skb,
saddr, daddr, udptable, proto);
/* Unicast */
sk = __udp6_lib_lookup_skb(skb, uh->source, uh->dest, udptable);
if (sk) {
if (!uh->check && !udp_sk(sk)->no_check6_rx)
goto report_csum_error;
return udp6_unicast_rcv_skb(sk, skb, uh);
}
if (!uh->check)
goto report_csum_error;
if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
goto discard;
if (udp_lib_checksum_complete(skb))
goto csum_error;
__UDP6_INC_STATS(net, UDP_MIB_NOPORTS, proto == IPPROTO_UDPLITE);
icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);
kfree_skb(skb);
return 0;
short_packet:
net_dbg_ratelimited("UDP%sv6: short packet: From [%pI6c]:%u %d/%d to [%pI6c]:%u\n",
proto == IPPROTO_UDPLITE ? "-Lite" : "",
saddr, ntohs(uh->source),
ulen, skb->len,
daddr, ntohs(uh->dest));
goto discard;
report_csum_error:
udp6_csum_zero_error(skb);
csum_error:
__UDP6_INC_STATS(net, UDP_MIB_CSUMERRORS, proto == IPPROTO_UDPLITE);
discard:
__UDP6_INC_STATS(net, UDP_MIB_INERRORS, proto == IPPROTO_UDPLITE);
kfree_skb(skb);
return 0;
}
static struct sock *__udp6_lib_demux_lookup(struct net *net,
__be16 loc_port, const struct in6_addr *loc_addr,
__be16 rmt_port, const struct in6_addr *rmt_addr,
int dif, int sdif)
{
unsigned short hnum = ntohs(loc_port);
unsigned int hash2 = ipv6_portaddr_hash(net, loc_addr, hnum);
unsigned int slot2 = hash2 & udp_table.mask;
struct udp_hslot *hslot2 = &udp_table.hash2[slot2];
const __portpair ports = INET_COMBINED_PORTS(rmt_port, hnum);
struct sock *sk;
udp_portaddr_for_each_entry_rcu(sk, &hslot2->head) {
if (sk->sk_state == TCP_ESTABLISHED &&
INET6_MATCH(sk, net, rmt_addr, loc_addr, ports, dif, sdif))
return sk;
/* Only check first socket in chain */
break;
}
return NULL;
}
INDIRECT_CALLABLE_SCOPE void udp_v6_early_demux(struct sk_buff *skb)
{
struct net *net = dev_net(skb->dev);
const struct udphdr *uh;
struct sock *sk;
struct dst_entry *dst;
int dif = skb->dev->ifindex;
int sdif = inet6_sdif(skb);
if (!pskb_may_pull(skb, skb_transport_offset(skb) +
sizeof(struct udphdr)))
return;
uh = udp_hdr(skb);
if (skb->pkt_type == PACKET_HOST)
sk = __udp6_lib_demux_lookup(net, uh->dest,
&ipv6_hdr(skb)->daddr,
uh->source, &ipv6_hdr(skb)->saddr,
dif, sdif);
else
return;
if (!sk || !refcount_inc_not_zero(&sk->sk_refcnt))
return;
skb->sk = sk;
skb->destructor = sock_efree;
dst = READ_ONCE(sk->sk_rx_dst);