/* 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.
*
* Definitions for the UDP module.
*
* Version: @(#)udp.h 1.0.2 05/07/93
*
* Authors: Ross Biro
* Fred N. van Kempen, <[email protected]>
*
* Fixes:
* Alan Cox : Turned on udp checksums. I don't want to
* chase 'memory corruption' bugs that aren't!
*/
#ifndef _UDP_H
#define _UDP_H
#include <linux/list.h>
#include <linux/bug.h>
#include <net/inet_sock.h>
#include <net/gso.h>
#include <net/sock.h>
#include <net/snmp.h>
#include <net/ip.h>
#include <linux/ipv6.h>
#include <linux/seq_file.h>
#include <linux/poll.h>
#include <linux/indirect_call_wrapper.h>
/**
* struct udp_skb_cb - UDP(-Lite) private variables
*
* @header: private variables used by IPv4/IPv6
* @cscov: checksum coverage length (UDP-Lite only)
* @partial_cov: if set indicates partial csum coverage
*/
struct udp_skb_cb {
union {
struct inet_skb_parm h4;
#if IS_ENABLED(CONFIG_IPV6)
struct inet6_skb_parm h6;
#endif
} header;
__u16 cscov;
__u8 partial_cov;
};
#define UDP_SKB_CB(__skb) ((struct udp_skb_cb *)((__skb)->cb))
/**
* struct udp_hslot - UDP hash slot
*
* @head: head of list of sockets
* @count: number of sockets in 'head' list
* @lock: spinlock protecting changes to head/count
*/
struct udp_hslot {
struct hlist_head head;
int count;
spinlock_t lock;
} __attribute__((aligned(2 * sizeof(long))));
/**
* struct udp_table - UDP table
*
* @hash: hash table, sockets are hashed on (local port)
* @hash2: hash table, sockets are hashed on (local port, local address)
* @mask: number of slots in hash tables, minus 1
* @log: log2(number of slots in hash table)
*/
struct udp_table {
struct udp_hslot *hash;
struct udp_hslot *hash2;
unsigned int mask;
unsigned int log;
};
extern struct udp_table udp_table;
void udp_table_init(struct udp_table *, const char *);
static inline struct udp_hslot *udp_hashslot(struct udp_table *table,
const struct net *net,
unsigned int num)
{
return &table->hash[udp_hashfn(net, num, table->mask)];
}
/*
* For secondary hash, net_hash_mix() is performed before calling
* udp_hashslot2(), this explains difference with udp_hashslot()
*/
static inline struct udp_hslot *udp_hashslot2(struct udp_table *table,
unsigned int hash)
{
return &table->hash2[hash & table->mask];
}
extern struct proto udp_prot;
extern atomic_long_t udp_memory_allocated;
DECLARE_PER_CPU(int, udp_memory_per_cpu_fw_alloc);
/* sysctl variables for udp */
extern long sysctl_udp_mem[3];
extern int sysctl_udp_rmem_min;
extern int sysctl_udp_wmem_min;
struct sk_buff;
/*
* Generic checksumming routines for UDP(-Lite) v4 and v6
*/
static inline __sum16 __udp_lib_checksum_complete(struct sk_buff *skb)
{
return (UDP_SKB_CB(skb)->cscov == skb->len ?
__skb_checksum_complete(skb) :
__skb_checksum_complete_head(skb, UDP_SKB_CB(skb)->cscov));
}
static inline int udp_lib_checksum_complete(struct sk_buff *skb)
{
return !skb_csum_unnecessary(skb) &&
__udp_lib_checksum_complete(skb);
}
/**
* udp_csum_outgoing - compute UDPv4/v6 checksum over fragments
* @sk: socket we are writing to
* @skb: sk_buff containing the filled-in UDP header
* (checksum field must be zeroed out)
*/
static inline __wsum udp_csum_outgoing(struct sock *sk, struct sk_buff *skb)
{
__wsum csum = csum_partial(skb_transport_header(skb),
sizeof(struct udphdr), 0);
skb_queue_walk(&sk->sk_write_queue, skb) {
csum = csum_add(csum, skb->csum);
}
return csum;
}
static inline __wsum udp_csum(struct sk_buff *skb)
{
__wsum csum = csum_partial(skb_transport_header(skb),
sizeof(struct udphdr), skb->csum);
for (skb = skb_shinfo(skb)->frag_list; skb; skb = skb->next) {
csum = csum_add(csum, skb->csum);
}
return csum;
}
static inline __sum16 udp_v4_check(int len, __be32 saddr,
__be32 daddr, __wsum base)
{
return csum_tcpudp_magic(saddr, daddr, len, IPPROTO_UDP, base);
}
void udp_set_csum(bool nocheck, struct sk_buff *skb,
__be32 saddr, __be32 daddr, int len);
static inline void udp_csum_pull_header(struct sk_buff *skb)
{
if (!skb->csum_valid && skb->ip_summed == CHECKSUM_NONE)
skb->csum = csum_partial(skb->data, sizeof(struct udphdr),
skb->csum);
skb_pull_rcsum(skb, sizeof(struct udphdr));
UDP_SKB_CB(skb)->cscov -= sizeof(struct udphdr);
}
typedef struct sock *(*udp_lookup_t)(const struct sk_buff *skb, __be16 sport,
__be16 dport);
void udp_v6_early_demux(struct sk_buff *skb);
INDIRECT_CALLABLE_DECLARE(int udpv6_rcv(struct sk_buff *));
struct sk_buff *__udp_gso_segment(struct sk_buff *gso_skb,
netdev_features_t features, bool is_ipv6);
static inline void udp_lib_init_sock(struct sock *sk)
{
struct udp_sock *up = udp_sk(sk);
skb_queue_head_init(&up->reader_queue);
up->forward_threshold = sk->sk_rcvbuf >> 2;
set_bit(SOCK_CUSTOM_SOCKOPT, &sk->sk_socket->flags);
}
/* hash routines shared between UDPv4/6 and UDP-Litev4/6 */
static inline int udp_lib_hash(struct sock *sk)
{
BUG();
return 0;
}
void udp_lib_unhash(struct sock *sk);
void udp_lib_rehash(struct sock *sk, u16 new_hash);
static inline void udp_lib_close(struct sock *sk, long timeout)
{
sk_common_release(sk);
}
int udp_lib_get_port(struct sock *sk, unsigned short snum,
unsigned int hash2_nulladdr);
u32 udp_flow_hashrnd(void);
static inline __be16 udp_flow_src_port(struct net *net, struct sk_buff *skb,
int min, int max, bool use_eth)
{
u32 hash;
if (min >= max) {
/* Use default range */
inet_get_local_port_range(net, &min, &max);
}
hash = skb_get_hash(skb);
if (unlikely(!hash)) {
if (use_eth) {
/* Can't find a normal hash, caller has indicated an
* Ethernet packet so use that to compute a hash.
*/
hash = jhash(skb->data, 2 * ETH_ALEN,
(__force u32) skb->protocol);
} else {
/* Can't derive any sort of hash for the packet, set
* to some consistent random value.
*/
hash = udp_flow_hashrnd();
}
}
/* Since this is being sent on the wire obfuscate hash a bit
* to minimize possibility that any useful information to an
* attacker is leaked. Only upper 16 bits are relevant in the
* computation for 16 bit port value.
*/
hash ^= hash << 16;
return htons((((u64) hash * (max - min)) >> 32) + min);
}
static inline int udp_rqueue_get(struct sock *sk)
{
return sk_rmem_alloc_get(sk) - READ_ONCE(udp_sk(sk)->forward_deficit);
}
static inline bool udp_sk_bound_dev_eq(const struct net *net, int bound_dev_if,
int dif, int sdif)
{
#if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
return inet_bound_dev_eq(!!READ_ONCE(net->ipv4.sysctl_udp_l3mdev_accept),
bound_dev_if, dif, sdif);
#else
return inet_bound_dev_eq(true, bound_dev_if, dif, sdif);
#endif
}
/* net/ipv4/udp.c */
void udp_destruct_common(struct sock *sk);
void skb_consume_udp(struct sock *sk, struct sk_buff *skb, int len);
int __udp_enqueue_schedule_skb(struct sock *sk, struct sk_buff *skb);
void udp_skb_destructor(struct sock *sk, struct sk_buff *skb);
struct sk_buff *__skb_recv_udp(struct sock *sk, unsigned int flags, int *off,
int *err);
static inline struct sk_buff *skb_recv_udp(struct sock *sk, unsigned int flags,
int *err)
{
int off = 0;
return __skb_recv_udp(sk, flags, &off, err);
}
int udp_v4_early_demux(struct sk_buff *skb);
bool udp_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst);
int udp_err(struct sk_buff *, u32);
int udp_abort(struct sock *sk, int err);
int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len);
void udp_splice_eof(struct socket *sock);
int udp_push_pending_frames(struct sock *sk);
void udp_flush_pending_frames(struct sock *sk);
int udp_cmsg_send(struct sock *sk, struct msghdr *msg, u16 *gso_size);
void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst);
int udp_rcv(struct sk_buff *skb);
int udp_ioctl(struct sock *sk, int cmd, int *karg);
int udp_init_sock(struct sock *sk);
int udp_pre_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len);
int __udp_disconnect(struct sock *sk, int flags);
int udp_disconnect(struct sock *sk, int flags);
__poll_t udp_poll(struct file *file, struct socket *sock, poll_table *wait);
struct sk_buff *skb_udp_tunnel_segment(struct sk_buff *skb,
netdev_features_t features,
bool is_ipv6);
int udp_lib_getsockopt(struct sock *sk, int level, int optname,
char __user *optval, int __user *optlen);
int udp_lib_setsockopt(struct sock *sk, int level, int optname,
sockptr_t optval, unsigned int optlen,
int (*push_pending_frames)(struct sock *));
struct sock *udp4_lib_lookup(const struct net *net, __be32 saddr, __be16 sport,
__be32 daddr, __be16 dport, int dif);
struct sock *__udp4_lib_lookup(const struct net *net, __be32 saddr,
__be16 sport,
__be32 daddr, __be16 dport, int dif, int sdif,
struct udp_table *tbl, struct sk_buff *skb);
struct sock *udp4_lib_lookup_skb(const struct sk_buff *skb,
__be16 sport, __be16 dport);
struct sock *udp6_lib_lookup(const struct net *net,
const struct in6_addr *saddr, __be16 sport,
const struct in6_addr *daddr, __be16 dport,
int dif);
struct sock *__udp6_lib_lookup(const struct net *net,
const struct in6_addr *saddr, __be16 sport,
const struct in6_addr *daddr, __be16 dport,
int dif, int sdif, struct udp_table *tbl,
struct sk_buff *skb);
struct sock *udp6_lib_lookup_skb(const struct sk_buff *skb,
__be16 sport, __be16 dport);
int udp_read_skb(struct sock *sk, skb_read_actor_t recv_actor);
/* UDP uses skb->dev_scratch to cache as much information as possible and avoid
* possibly multiple cache miss on dequeue()
*/
struct udp_dev_scratch {
/* skb->truesize and the stateless bit are embedded in a single field;
* do not use a bitfield since the compiler emits better/smaller code
* this way
*/
u32 _tsize_state;
#if BITS_PER_LONG == 64
/* len and the bit needed to compute skb_csum_unnecessary
* will be on cold cache lines at recvmsg time.
* skb->len can be stored on 16 bits since the udp header has been
* already validated and pulled.
*/
u16 len;
bool is_linear;
bool csum_unnecessary;
#endif
};
static inline struct udp_dev_scratch *udp_skb_scratch(struct sk_buff *skb)
{
return (struct udp_dev_scratch *)&skb->dev_scratch;
}
#if BITS_PER_LONG == 64
static inline unsigned int udp_skb_len(struct sk_buff *skb)
{
return udp_skb_scratch(skb)->len;
}
static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb)
{
return udp_skb_scratch(skb)->csum_unnecessary;
}
static inline bool udp_skb_is_linear(struct sk_buff *skb)
{
return udp_skb_scratch(skb)->is_linear;
}
#else
static inline unsigned int udp_skb_len(struct sk_buff *skb)
{
return skb->len;
}
static inline bool udp_skb_csum_unnecessary(struct sk_buff *skb)
{
return skb_csum_unnecessary(skb);
}
static inline bool udp_skb_is_linear(struct sk_buff *skb)
{
return !skb_is_nonlinear(skb);
}
#endif
static inline int copy_linear_skb(struct sk_buff *skb, int len, int off,
struct iov_iter *to)
{
return copy_to_iter_full(skb->data + off, len, to) ? 0 : -EFAULT;
}
/*
* SNMP statistics for UDP and UDP-Lite
*/
#define UDP_INC_STATS(net, field, is_udplite) do { \
if (is_udplite) SNMP_INC_STATS((net)->mib.udplite_statistics, field); \
else SNMP_INC_STATS((net)->mib.udp_statistics, field); } while(0)
#define __UDP_INC_STATS(net, field, is_udplite) do { \
if (is_udplite) __SNMP_INC_STATS((net)->mib.udplite_statistics, field); \
else __SNMP_INC_STATS((net)->mib.udp_statistics, field); } while(0)
#define __UDP6_INC_STATS(net, field, is_udplite) do { \
if (is_udplite) __SNMP_INC_STATS((net)->mib.udplite_stats_in6, field);\
else __SNMP_INC_STATS((net)->mib.udp_stats_in6, field); \
} while(0)
#define UDP6_INC_STATS(net, field, __lite) do { \
if (__lite) SNMP_INC_STATS((net)->mib.udplite_stats_in6, field); \
else SNMP_INC_STATS((net)->mib.udp_stats_in6, field); \
} while(0)
#if IS_ENABLED(CONFIG_IPV6)
#define __UDPX_MIB(sk, ipv4) \
({ \
ipv4 ? (IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_statistics : \
sock_net(sk)->mib.udp_statistics) : \
(IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_stats_in6 : \
sock_net(sk)->mib.udp_stats_in6); \
})
#else
#define __UDPX_MIB(sk, ipv4) \
({ \
IS_UDPLITE(sk) ? sock_net(sk)->mib.udplite_statistics : \
sock_net(sk)->mib.udp_statistics; \
})
#endif
#define __UDPX_INC_STATS(sk, field) \
__SNMP_INC_STATS(__UDPX_MIB(sk, (sk)->sk_family == AF_INET), field)
#ifdef CONFIG_PROC_FS
struct udp_seq_afinfo {
sa_family_t family;
struct udp_table *udp_table;
};
struct udp_iter_state {
struct seq_net_private p;
int bucket;
};
void *udp_seq_start(struct seq_file *seq, loff_t *pos);
void *udp_seq_next(struct seq_file *seq, void *v, loff_t *pos);
void udp_seq_stop(struct seq_file *seq, void *v);
extern const struct seq_operations udp_seq_ops;
extern const struct seq_operations udp6_seq_ops;
int udp4_proc_init(void);
void udp4_proc_exit(void);
#endif /* CONFIG_PROC_FS */
int udpv4_offload_init(void);
void udp_init(void);
DECLARE_STATIC_KEY_FALSE(udp_encap_needed_key);
void udp_encap_enable(void);
void udp_encap_disable(void);
#if IS_ENABLED(CONFIG_IPV6)
DECLARE_STATIC_KEY_FALSE(udpv6_encap_needed_key);
void udpv6_encap_enable(void);
#endif
static inline struct sk_buff *udp_rcv_segment(struct sock *sk,
struct sk_buff *skb, bool ipv4)
{
netdev_features_t features = NETIF_F_SG;
struct sk_buff *segs;
/* Avoid csum recalculation by skb_segment unless userspace explicitly
* asks for the final checksum values
*/
if (!inet_get_convert_csum(sk))
features |= NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM;
/* UDP segmentation expects packets of type CHECKSUM_PARTIAL or
* CHECKSUM_NONE in __udp_gso_segment. UDP GRO indeed builds partial
* packets in udp_gro_complete_segment. As does UDP GSO, verified by
* udp_send_skb. But when those packets are looped in dev_loopback_xmit
* their ip_summed CHECKSUM_NONE is changed to CHECKSUM_UNNECESSARY.
* Reset in this specific case, where PARTIAL is both correct and
* required.
*/
if (skb->pkt_type == PACKET_LOOPBACK)
skb->ip_summed = CHECKSUM_PARTIAL;
/* the GSO CB lays after the UDP one, no need to save and restore any
* CB fragment
*/
segs = __skb_gso_segment(skb, features, false);
if (IS_ERR_OR_NULL(segs)) {
int segs_nr = skb_shinfo(skb)->gso_segs;
atomic_add(segs_nr, &sk->sk_drops);
SNMP_ADD_STATS(__UDPX_MIB(sk, ipv4), UDP_MIB_INERRORS, segs_nr);
kfree_skb(skb);
return NULL;
}
consume_skb(skb);
return segs;
}
static inline void udp_post_segment_fix_csum(struct sk_buff *skb)
{
/* UDP-lite can't land here - no GRO */
WARN_ON_ONCE(UDP_SKB_CB(skb)->partial_cov);
/* UDP packets generated with UDP_SEGMENT and traversing:
*
* UDP tunnel(xmit) -> veth (segmentation) -> veth (gro) -> UDP tunnel (rx)
*
* can reach an UDP socket with CHECKSUM_NONE, because
* __iptunnel_pull_header() converts CHECKSUM_PARTIAL into NONE.
* SKB_GSO_UDP_L4 or SKB_GSO_FRAGLIST packets with no UDP tunnel will
* have a valid checksum, as the GRO engine validates the UDP csum
* before the aggregation and nobody strips such info in between.
* Instead of adding another check in the tunnel fastpath, we can force
* a valid csum after the segmentation.
* Additionally fixup the UDP CB.
*/
UDP_SKB_CB(skb)->cscov = skb->len;
if (skb->ip_summed == CHECKSUM_NONE && !skb->csum_valid)
skb->csum_valid = 1;
}
#ifdef CONFIG_BPF_SYSCALL
struct sk_psock;
int udp_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore);
#endif
#endif /* _UDP_H */
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