diff options
Diffstat (limited to 'net')
| -rw-r--r-- | net/Kconfig | 1 | ||||
| -rw-r--r-- | net/Makefile | 1 | ||||
| -rw-r--r-- | net/strparser/Kconfig | 4 | ||||
| -rw-r--r-- | net/strparser/Makefile | 1 | ||||
| -rw-r--r-- | net/strparser/strparser.c | 492 |
5 files changed, 499 insertions, 0 deletions
diff --git a/net/Kconfig b/net/Kconfig index c2cdbce629bd..7b6cd340b72b 100644 --- a/net/Kconfig +++ b/net/Kconfig @@ -369,6 +369,7 @@ source "net/irda/Kconfig" source "net/bluetooth/Kconfig" source "net/rxrpc/Kconfig" source "net/kcm/Kconfig" +source "net/strparser/Kconfig" config FIB_RULES bool diff --git a/net/Makefile b/net/Makefile index 9bd20bb86cc6..4cafaa2b4667 100644 --- a/net/Makefile +++ b/net/Makefile @@ -35,6 +35,7 @@ obj-$(CONFIG_BT) += bluetooth/ obj-$(CONFIG_SUNRPC) += sunrpc/ obj-$(CONFIG_AF_RXRPC) += rxrpc/ obj-$(CONFIG_AF_KCM) += kcm/ +obj-$(CONFIG_STREAM_PARSER) += strparser/ obj-$(CONFIG_ATM) += atm/ obj-$(CONFIG_L2TP) += l2tp/ obj-$(CONFIG_DECNET) += decnet/ diff --git a/net/strparser/Kconfig b/net/strparser/Kconfig new file mode 100644 index 000000000000..6cff3f6d0c3a --- /dev/null +++ b/net/strparser/Kconfig @@ -0,0 +1,4 @@ + +config STREAM_PARSER + tristate + default n diff --git a/net/strparser/Makefile b/net/strparser/Makefile new file mode 100644 index 000000000000..858a126ebaa0 --- /dev/null +++ b/net/strparser/Makefile @@ -0,0 +1 @@ +obj-$(CONFIG_STREAM_PARSER) += strparser.o diff --git a/net/strparser/strparser.c b/net/strparser/strparser.c new file mode 100644 index 000000000000..fd688c0a7744 --- /dev/null +++ b/net/strparser/strparser.c @@ -0,0 +1,492 @@ +/* + * 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> +#include <net/tcp.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); +} + +/* Lower socket lock held */ +static int strp_tcp_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, err, desc); + break; + } else if (len > strp->sk->sk_rcvbuf) { + /* Message length exceeds maximum allowed */ + STRP_STATS_INCR(strp->stats.rx_msg_too_big); + strp_parser_err(strp, -EMSGSIZE, desc); + break; + } else if (len <= (ssize_t)head->len - + skb->len - rxm->strp.offset) { + /* Length must be into new skb (and also + * greater than zero) + */ + STRP_STATS_INCR(strp->stats.rx_bad_hdr_len); + strp_parser_err(strp, -EPROTO, desc); + break; + } + + rxm->strp.full_len = len; + } + + extra = (ssize_t)(rxm->accum_len + cand_len) - + rxm->strp.full_len; + + if (extra < 0) { + /* Message not complete yet. */ + if (rxm->strp.full_len - rxm->accum_len > + tcp_inq(strp->sk)) { + /* Don't have the whole messages in the socket + * buffer. Set strp->rx_need_bytes to wait for + * the rest of the message. Also, set "early + * eaten" since we've already buffered the skb + * but don't consume yet per tcp_read_sock. + */ + + if (!rxm->accum_len) { + /* Start RX timer for new message */ + strp_start_rx_timer(strp); + } + + strp->rx_need_bytes = rxm->strp.full_len - + rxm->accum_len; + rxm->accum_len += cand_len; + rxm->early_eaten = cand_len; + STRP_STATS_ADD(strp->stats.rx_bytes, cand_len); + desc->count = 0; /* Stop reading socket */ + break; + } + rxm->accum_len += cand_len; + eaten += cand_len; + WARN_ON(eaten != orig_len); + break; + } + + /* Positive extra indicates ore bytes than needed for the + * message + */ + + WARN_ON(extra > cand_len); + + eaten += (cand_len - extra); + + /* Hurray, we have a new message! */ + del_timer(&strp->rx_msg_timer); + strp->rx_skb_head = NULL; + STRP_STATS_INCR(strp->stats.rx_msgs); + + /* Give skb to upper layer */ + strp->cb.rcv_msg(strp, head); + + if (unlikely(strp->rx_paused)) { + /* Upper layer paused strp */ + break; + } + } + + if (cloned_orig) + kfree_skb(orig_skb); + + STRP_STATS_ADD(strp->stats.rx_bytes, eaten); + + return eaten; +} + +static int default_read_sock_done(struct strparser *strp, int err) +{ + return err; +} + +/* Called with lock held on lower socket */ +static int strp_tcp_read_sock(struct strparser *strp) +{ + read_descriptor_t desc; + + desc.arg.data = strp; + desc.error = 0; + desc.count = 1; /* give more than one skb per call */ + + /* sk should be locked here, so okay to do tcp_read_sock */ + tcp_read_sock(strp->sk, &desc, strp_tcp_recv); + + desc.error = strp->cb.read_sock_done(strp, desc.error); + + return desc.error; +} + +/* Lower sock lock held */ +void strp_tcp_data_ready(struct strparser *strp) +{ + struct sock *csk = strp->sk; + + if (unlikely(strp->rx_stopped)) + return; + + /* This check is needed to synchronize with do_strp_rx_work. + * do_strp_rx_work acquires a process lock (lock_sock) whereas + * the lock held here is bh_lock_sock. The two locks can be + * held by different threads at the same time, but bh_lock_sock + * allows a thread in BH context to safely check if the process + * lock is held. In this case, if the lock is held, queue work. + */ + if (sock_owned_by_user(csk)) { + queue_work(strp_wq, &strp->rx_work); + return; + } + + if (strp->rx_paused) + return; + + if (strp->rx_need_bytes) { + if (tcp_inq(csk) >= strp->rx_need_bytes) + strp->rx_need_bytes = 0; + else + return; + } + + if (strp_tcp_read_sock(strp) == -ENOMEM) + queue_work(strp_wq, &strp->rx_work); +} +EXPORT_SYMBOL_GPL(strp_tcp_data_ready); + +static void do_strp_rx_work(struct strparser *strp) +{ + read_descriptor_t rd_desc; + struct sock *csk = strp->sk; + + /* We need the read lock to synchronize with strp_tcp_data_ready. We + * need the socket lock for calling tcp_read_sock. + */ + lock_sock(csk); + + if (unlikely(csk->sk_user_data != strp)) + goto out; + + if (unlikely(strp->rx_stopped)) + goto out; + + if (strp->rx_paused) + goto out; + + rd_desc.arg.data = strp; + + if (strp_tcp_read_sock(strp) == -ENOMEM) + queue_work(strp_wq, &strp->rx_work); + +out: + release_sock(csk); +} + +static void strp_rx_work(struct work_struct *w) +{ + do_strp_rx_work(container_of(w, struct strparser, rx_work)); +} + +static void strp_rx_msg_timeout(unsigned long arg) +{ + struct strparser *strp = (struct strparser *)arg; + + /* Message assembly timed out */ + STRP_STATS_INCR(strp->stats.rx_msg_timeouts); + lock_sock(strp->sk); + strp->cb.abort_parser(strp, ETIMEDOUT); + release_sock(strp->sk); +} + +int strp_init(struct strparser *strp, struct sock *csk, + struct strp_callbacks *cb) +{ + if (!cb || !cb->rcv_msg || !cb->parse_msg) + return -EINVAL; + + memset(strp, 0, sizeof(*strp)); + + strp->sk = csk; + + setup_timer(&strp->rx_msg_timer, strp_rx_msg_timeout, + (unsigned long)strp); + + INIT_WORK(&strp->rx_work, strp_rx_work); + + strp->cb.rcv_msg = cb->rcv_msg; + strp->cb.parse_msg = cb->parse_msg; + strp->cb.read_sock_done = cb->read_sock_done ? : default_read_sock_done; + strp->cb.abort_parser = cb->abort_parser ? : strp_abort_rx_strp; + + return 0; +} +EXPORT_SYMBOL_GPL(strp_init); + +/* strp must already be stopped so that strp_tcp_recv will no longer be called. + * Note that strp_done is not called with the lower socket held. + */ +void strp_done(struct strparser *strp) +{ + WARN_ON(!strp->rx_stopped); + + del_timer_sync(&strp->rx_msg_timer); + cancel_work_sync(&strp->rx_work); + + if (strp->rx_skb_head) { + kfree_skb(strp->rx_skb_head); + strp->rx_skb_head = NULL; + } +} +EXPORT_SYMBOL_GPL(strp_done); + +void strp_stop(struct strparser *strp) +{ + strp->rx_stopped = 1; +} +EXPORT_SYMBOL_GPL(strp_stop); + +void strp_check_rcv(struct strparser *strp) +{ + queue_work(strp_wq, &strp->rx_work); +} +EXPORT_SYMBOL_GPL(strp_check_rcv); + +static int __init strp_mod_init(void) +{ + strp_wq = create_singlethread_workqueue("kstrp"); + + return 0; +} + +static void __exit strp_mod_exit(void) +{ +} +module_init(strp_mod_init); +module_exit(strp_mod_exit); +MODULE_LICENSE("GPL"); |