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/*
* Stream Parser
*
* Copyright (c) 2016 Tom Herbert <tom@herbertland.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation.
*/
#include <linux/bpf.h>
#include <linux/errno.h>
#include <linux/errqueue.h>
#include <linux/file.h>
#include <linux/in.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/net.h>
#include <linux/netdevice.h>
#include <linux/poll.h>
#include <linux/rculist.h>
#include <linux/skbuff.h>
#include <linux/socket.h>
#include <linux/uaccess.h>
#include <linux/workqueue.h>
#include <net/strparser.h>
#include <net/netns/generic.h>
#include <net/sock.h>
static struct workqueue_struct *strp_wq;
struct _strp_rx_msg {
/* Internal cb structure. struct strp_rx_msg must be first for passing
* to upper layer.
*/
struct strp_rx_msg strp;
int accum_len;
int early_eaten;
};
static inline struct _strp_rx_msg *_strp_rx_msg(struct sk_buff *skb)
{
return (struct _strp_rx_msg *)((void *)skb->cb +
offsetof(struct qdisc_skb_cb, data));
}
/* Lower lock held */
static void strp_abort_rx_strp(struct strparser *strp, int err)
{
struct sock *csk = strp->sk;
/* Unrecoverable error in receive */
del_timer(&strp->rx_msg_timer);
if (strp->rx_stopped)
return;
strp->rx_stopped = 1;
/* Report an error on the lower socket */
csk->sk_err = err;
csk->sk_error_report(csk);
}
static void strp_start_rx_timer(struct strparser *strp)
{
if (strp->sk->sk_rcvtimeo)
mod_timer(&strp->rx_msg_timer, strp->sk->sk_rcvtimeo);
}
/* Lower lock held */
static void strp_parser_err(struct strparser *strp, int err,
read_descriptor_t *desc)
{
desc->error = err;
kfree_skb(strp->rx_skb_head);
strp->rx_skb_head = NULL;
strp->cb.abort_parser(strp, err);
}
static inline int strp_peek_len(struct strparser *strp)
{
struct socket *sock = strp->sk->sk_socket;
return sock->ops->peek_len(sock);
}
/* Lower socket lock held */
static int strp_recv(read_descriptor_t *desc, struct sk_buff *orig_skb,
unsigned int orig_offset, size_t orig_len)
{
struct strparser *strp = (struct strparser *)desc->arg.data;
struct _strp_rx_msg *rxm;
struct sk_buff *head, *skb;
size_t eaten = 0, cand_len;
ssize_t extra;
int err;
bool cloned_orig = false;
if (strp->rx_paused)
return 0;
head = strp->rx_skb_head;
if (head) {
/* Message already in progress */
rxm = _strp_rx_msg(head);
if (unlikely(rxm->early_eaten)) {
/* Already some number of bytes on the receive sock
* data saved in rx_skb_head, just indicate they
* are consumed.
*/
eaten = orig_len <= rxm->early_eaten ?
orig_len : rxm->early_eaten;
rxm->early_eaten -= eaten;
return eaten;
}
if (unlikely(orig_offset)) {
/* Getting data with a non-zero offset when a message is
* in progress is not expected. If it does happen, we
* need to clone and pull since we can't deal with
* offsets in the skbs for a message expect in the head.
*/
orig_skb = skb_clone(orig_skb, GFP_ATOMIC);
if (!orig_skb) {
STRP_STATS_INCR(strp->stats.rx_mem_fail);
desc->error = -ENOMEM;
return 0;
}
if (!pskb_pull(orig_skb, orig_offset)) {
STRP_STATS_INCR(strp->stats.rx_mem_fail);
kfree_skb(orig_skb);
desc->error = -ENOMEM;
return 0;
}
cloned_orig = true;
orig_offset = 0;
}
if (!strp->rx_skb_nextp) {
/* We are going to append to the frags_list of head.
* Need to unshare the frag_list.
*/
err = skb_unclone(head, GFP_ATOMIC);
if (err) {
STRP_STATS_INCR(strp->stats.rx_mem_fail);
desc->error = err;
return 0;
}
if (unlikely(skb_shinfo(head)->frag_list)) {
/* We can't append to an sk_buff that already
* has a frag_list. We create a new head, point
* the frag_list of that to the old head, and
* then are able to use the old head->next for
* appending to the message.
*/
if (WARN_ON(head->next)) {
desc->error = -EINVAL;
return 0;
}
skb = alloc_skb(0, GFP_ATOMIC);
if (!skb) {
STRP_STATS_INCR(strp->stats.rx_mem_fail);
desc->error = -ENOMEM;
return 0;
}
skb->len = head->len;
skb->data_len = head->len;
skb->truesize = head->truesize;
*_strp_rx_msg(skb) = *_strp_rx_msg(head);
strp->rx_skb_nextp = &head->next;
skb_shinfo(skb)->frag_list = head;
strp->rx_skb_head = skb;
head = skb;
} else {
strp->rx_skb_nextp =
&skb_shinfo(head)->frag_list;
}
}
}
while (eaten < orig_len) {
/* Always clone since we will consume something */
skb = skb_clone(orig_skb, GFP_ATOMIC);
if (!skb) {
STRP_STATS_INCR(strp->stats.rx_mem_fail);
desc->error = -ENOMEM;
break;
}
cand_len = orig_len - eaten;
head = strp->rx_skb_head;
if (!head) {
head = skb;
strp->rx_skb_head = head;
/* Will set rx_skb_nextp on next packet if needed */
strp->rx_skb_nextp = NULL;
rxm = _strp_rx_msg(head);
memset(rxm, 0, sizeof(*rxm));
rxm->strp.offset = orig_offset + eaten;
} else {
/* Unclone since we may be appending to an skb that we
* already share a frag_list with.
*/
err = skb_unclone(skb, GFP_ATOMIC);
if (err) {
STRP_STATS_INCR(strp->stats.rx_mem_fail);
desc->error = err;
break;
}
rxm = _strp_rx_msg(head);
*strp->rx_skb_nextp = skb;
strp->rx_skb_nextp = &skb->next;
head->data_len += skb->len;
head->len += skb->len;
head->truesize += skb->truesize;
}
if (!rxm->strp.full_len) {
ssize_t len;
len = (*strp->cb.parse_msg)(strp, head);
if (!len) {
/* Need more header to determine length */
if (!rxm->accum_len) {
/* Start RX timer for new message */
strp_start_rx_timer(strp);
}
rxm->accum_len += cand_len;
eaten += cand_len;
STRP_STATS_INCR(strp->stats.rx_need_more_hdr);
WARN_ON(eaten != orig_len);
break;
} else if (len < 0) {
if (len == -ESTRPIPE && rxm->accum_len) {
len = -ENODATA;
strp->rx_unrecov_intr = 1;
} else {
strp->rx_interrupted = 1;
}
strp_parser_err(strp, len, desc);
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