// SPDX-License-Identifier: GPL-2.0 /* * SUCS NET3: * * Generic datagram handling routines. These are generic for all * protocols. Possibly a generic IP version on top of these would * make sense. Not tonight however 8-). * This is used because UDP, RAW, PACKET, DDP, IPX, AX.25 and * NetROM layer all have identical poll code and mostly * identical recvmsg() code. So we share it here. The poll was * shared before but buried in udp.c so I moved it. * * Authors: Alan Cox <[email protected]>. (datagram_poll() from old * udp.c code) * * Fixes: * Alan Cox : NULL return from skb_peek_copy() * understood * Alan Cox : Rewrote skb_read_datagram to avoid the * skb_peek_copy stuff. * Alan Cox : Added support for SOCK_SEQPACKET. * IPX can no longer use the SO_TYPE hack * but AX.25 now works right, and SPX is * feasible. * Alan Cox : Fixed write poll of non IP protocol * crash. * Florian La Roche: Changed for my new skbuff handling. * Darryl Miles : Fixed non-blocking SOCK_SEQPACKET. * Linus Torvalds : BSD semantic fixes. * Alan Cox : Datagram iovec handling * Darryl Miles : Fixed non-blocking SOCK_STREAM. * Alan Cox : POSIXisms * Pete Wyckoff : Unconnected accept() fix. * */ #include <linux/module.h> #include <linux/types.h> #include <linux/kernel.h> #include <linux/uaccess.h> #include <linux/mm.h> #include <linux/interrupt.h> #include <linux/errno.h> #include <linux/sched.h> #include <linux/inet.h> #include <linux/netdevice.h> #include <linux/rtnetlink.h> #include <linux/poll.h> #include <linux/highmem.h> #include <linux/spinlock.h> #include <linux/slab.h> #include <linux/pagemap.h> #include <linux/iov_iter.h> #include <linux/indirect_call_wrapper.h> #include <net/protocol.h> #include <linux/skbuff.h> #include <net/checksum.h> #include <net/sock.h> #include <net/tcp_states.h> #include <trace/events/skb.h> #include <net/busy_poll.h> #include <crypto/hash.h> /* * Is a socket 'connection oriented' ? */ static inline int connection_based(struct sock *sk) { … } static int receiver_wake_function(wait_queue_entry_t *wait, unsigned int mode, int sync, void *key) { … } /* * Wait for the last received packet to be different from skb */ int __skb_wait_for_more_packets(struct sock *sk, struct sk_buff_head *queue, int *err, long *timeo_p, const struct sk_buff *skb) { … } EXPORT_SYMBOL(…); static struct sk_buff *skb_set_peeked(struct sk_buff *skb) { … } struct sk_buff *__skb_try_recv_from_queue(struct sock *sk, struct sk_buff_head *queue, unsigned int flags, int *off, int *err, struct sk_buff **last) { … } /** * __skb_try_recv_datagram - Receive a datagram skbuff * @sk: socket * @queue: socket queue from which to receive * @flags: MSG\_ flags * @off: an offset in bytes to peek skb from. Returns an offset * within an skb where data actually starts * @err: error code returned * @last: set to last peeked message to inform the wait function * what to look for when peeking * * Get a datagram skbuff, understands the peeking, nonblocking wakeups * and possible races. This replaces identical code in packet, raw and * udp, as well as the IPX AX.25 and Appletalk. It also finally fixes * the long standing peek and read race for datagram sockets. If you * alter this routine remember it must be re-entrant. * * This function will lock the socket if a skb is returned, so * the caller needs to unlock the socket in that case (usually by * calling skb_free_datagram). Returns NULL with @err set to * -EAGAIN if no data was available or to some other value if an * error was detected. * * * It does not lock socket since today. This function is * * free of race conditions. This measure should/can improve * * significantly datagram socket latencies at high loads, * * when data copying to user space takes lots of time. * * (BTW I've just killed the last cli() in IP/IPv6/core/netlink/packet * * 8) Great win.) * * --ANK (980729) * * The order of the tests when we find no data waiting are specified * quite explicitly by POSIX 1003.1g, don't change them without having * the standard around please. */ struct sk_buff *__skb_try_recv_datagram(struct sock *sk, struct sk_buff_head *queue, unsigned int flags, int *off, int *err, struct sk_buff **last) { … } EXPORT_SYMBOL(…); struct sk_buff *__skb_recv_datagram(struct sock *sk, struct sk_buff_head *sk_queue, unsigned int flags, int *off, int *err) { … } EXPORT_SYMBOL(…); struct sk_buff *skb_recv_datagram(struct sock *sk, unsigned int flags, int *err) { … } EXPORT_SYMBOL(…); void skb_free_datagram(struct sock *sk, struct sk_buff *skb) { … } EXPORT_SYMBOL(…); int __sk_queue_drop_skb(struct sock *sk, struct sk_buff_head *sk_queue, struct sk_buff *skb, unsigned int flags, void (*destructor)(struct sock *sk, struct sk_buff *skb)) { … } EXPORT_SYMBOL(…); /** * skb_kill_datagram - Free a datagram skbuff forcibly * @sk: socket * @skb: datagram skbuff * @flags: MSG\_ flags * * This function frees a datagram skbuff that was received by * skb_recv_datagram. The flags argument must match the one * used for skb_recv_datagram. * * If the MSG_PEEK flag is set, and the packet is still on the * receive queue of the socket, it will be taken off the queue * before it is freed. * * This function currently only disables BH when acquiring the * sk_receive_queue lock. Therefore it must not be used in a * context where that lock is acquired in an IRQ context. * * It returns 0 if the packet was removed by us. */ int skb_kill_datagram(struct sock *sk, struct sk_buff *skb, unsigned int flags) { … } EXPORT_SYMBOL(…); INDIRECT_CALLABLE_DECLARE(…); static int __skb_datagram_iter(const struct sk_buff *skb, int offset, struct iov_iter *to, int len, bool fault_short, size_t (*cb)(const void *, size_t, void *, struct iov_iter *), void *data) { … } static size_t hash_and_copy_to_iter(const void *addr, size_t bytes, void *hashp, struct iov_iter *i) { … } /** * skb_copy_and_hash_datagram_iter - Copy datagram to an iovec iterator * and update a hash. * @skb: buffer to copy * @offset: offset in the buffer to start copying from * @to: iovec iterator to copy to * @len: amount of data to copy from buffer to iovec * @hash: hash request to update */ int skb_copy_and_hash_datagram_iter(const struct sk_buff *skb, int offset, struct iov_iter *to, int len, struct ahash_request *hash) { … } EXPORT_SYMBOL(…); static size_t simple_copy_to_iter(const void *addr, size_t bytes, void *data __always_unused, struct iov_iter *i) { … } /** * skb_copy_datagram_iter - Copy a datagram to an iovec iterator. * @skb: buffer to copy * @offset: offset in the buffer to start copying from * @to: iovec iterator to copy to * @len: amount of data to copy from buffer to iovec */ int skb_copy_datagram_iter(const struct sk_buff *skb, int offset, struct iov_iter *to, int len) { … } EXPORT_SYMBOL(…); /** * skb_copy_datagram_from_iter - Copy a datagram from an iov_iter. * @skb: buffer to copy * @offset: offset in the buffer to start copying to * @from: the copy source * @len: amount of data to copy to buffer from iovec * * Returns 0 or -EFAULT. */ int skb_copy_datagram_from_iter(struct sk_buff *skb, int offset, struct iov_iter *from, int len) { … } EXPORT_SYMBOL(…); int zerocopy_fill_skb_from_iter(struct sk_buff *skb, struct iov_iter *from, size_t length) { … } int __zerocopy_sg_from_iter(struct msghdr *msg, struct sock *sk, struct sk_buff *skb, struct iov_iter *from, size_t length) { … } EXPORT_SYMBOL(…); /** * zerocopy_sg_from_iter - Build a zerocopy datagram from an iov_iter * @skb: buffer to copy * @from: the source to copy from * * The function will first copy up to headlen, and then pin the userspace * pages and build frags through them. * * Returns 0, -EFAULT or -EMSGSIZE. */ int zerocopy_sg_from_iter(struct sk_buff *skb, struct iov_iter *from) { … } EXPORT_SYMBOL(…); static __always_inline size_t copy_to_user_iter_csum(void __user *iter_to, size_t progress, size_t len, void *from, void *priv2) { … } static __always_inline size_t memcpy_to_iter_csum(void *iter_to, size_t progress, size_t len, void *from, void *priv2) { … } struct csum_state { … }; static size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *_csstate, struct iov_iter *i) { … } /** * skb_copy_and_csum_datagram - Copy datagram to an iovec iterator * and update a checksum. * @skb: buffer to copy * @offset: offset in the buffer to start copying from * @to: iovec iterator to copy to * @len: amount of data to copy from buffer to iovec * @csump: checksum pointer */ static int skb_copy_and_csum_datagram(const struct sk_buff *skb, int offset, struct iov_iter *to, int len, __wsum *csump) { … } /** * skb_copy_and_csum_datagram_msg - Copy and checksum skb to user iovec. * @skb: skbuff * @hlen: hardware length * @msg: destination * * Caller _must_ check that skb will fit to this iovec. * * Returns: 0 - success. * -EINVAL - checksum failure. * -EFAULT - fault during copy. */ int skb_copy_and_csum_datagram_msg(struct sk_buff *skb, int hlen, struct msghdr *msg) { … } EXPORT_SYMBOL(…); /** * datagram_poll - generic datagram poll * @file: file struct * @sock: socket * @wait: poll table * * Datagram poll: Again totally generic. This also handles * sequenced packet sockets providing the socket receive queue * is only ever holding data ready to receive. * * Note: when you *don't* use this routine for this protocol, * and you use a different write policy from sock_writeable() * then please supply your own write_space callback. */ __poll_t datagram_poll(struct file *file, struct socket *sock, poll_table *wait) { … } EXPORT_SYMBOL(…);
Codebase Browser
linux