--- /dev/null
+/*
+ * 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.
+ */
+
+#ifndef __NET_STRPARSER_H_
+#define __NET_STRPARSER_H_
+
+#include <linux/skbuff.h>
+#include <net/sock.h>
+
+#define STRP_STATS_ADD(stat, count) ((stat) += (count))
+#define STRP_STATS_INCR(stat) ((stat)++)
+
+struct strp_stats {
+ unsigned long long rx_msgs;
+ unsigned long long rx_bytes;
+ unsigned int rx_mem_fail;
+ unsigned int rx_need_more_hdr;
+ unsigned int rx_msg_too_big;
+ unsigned int rx_msg_timeouts;
+ unsigned int rx_bad_hdr_len;
+};
+
+struct strp_aggr_stats {
+ unsigned long long rx_msgs;
+ unsigned long long rx_bytes;
+ unsigned int rx_mem_fail;
+ unsigned int rx_need_more_hdr;
+ unsigned int rx_msg_too_big;
+ unsigned int rx_msg_timeouts;
+ unsigned int rx_bad_hdr_len;
+ unsigned int rx_aborts;
+ unsigned int rx_interrupted;
+ unsigned int rx_unrecov_intr;
+};
+
+struct strparser;
+
+/* Callbacks are called with lock held for the attached socket */
+struct strp_callbacks {
+ int (*parse_msg)(struct strparser *strp, struct sk_buff *skb);
+ void (*rcv_msg)(struct strparser *strp, struct sk_buff *skb);
+ int (*read_sock_done)(struct strparser *strp, int err);
+ void (*abort_parser)(struct strparser *strp, int err);
+};
+
+struct strp_rx_msg {
+ int full_len;
+ int offset;
+};
+
+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));
+}
+
+/* Structure for an attached lower socket */
+struct strparser {
+ struct sock *sk;
+
+ u32 rx_stopped : 1;
+ u32 rx_paused : 1;
+ u32 rx_aborted : 1;
+ u32 rx_interrupted : 1;
+ u32 rx_unrecov_intr : 1;
+
+ struct sk_buff **rx_skb_nextp;
+ struct timer_list rx_msg_timer;
+ struct sk_buff *rx_skb_head;
+ unsigned int rx_need_bytes;
+ struct delayed_work rx_delayed_work;
+ struct work_struct rx_work;
+ struct strp_stats stats;
+ struct strp_callbacks cb;
+};
+
+/* Must be called with lock held for attached socket */
+static inline void strp_pause(struct strparser *strp)
+{
+ strp->rx_paused = 1;
+}
+
+/* May be called without holding lock for attached socket */
+static inline void strp_unpause(struct strparser *strp)
+{
+ strp->rx_paused = 0;
+}
+
+static inline void save_strp_stats(struct strparser *strp,
+ struct strp_aggr_stats *agg_stats)
+{
+ /* Save psock statistics in the mux when psock is being unattached. */
+
+#define SAVE_PSOCK_STATS(_stat) (agg_stats->_stat += \
+ strp->stats._stat)
+ SAVE_PSOCK_STATS(rx_msgs);
+ SAVE_PSOCK_STATS(rx_bytes);
+ SAVE_PSOCK_STATS(rx_mem_fail);
+ SAVE_PSOCK_STATS(rx_need_more_hdr);
+ SAVE_PSOCK_STATS(rx_msg_too_big);
+ SAVE_PSOCK_STATS(rx_msg_timeouts);
+ SAVE_PSOCK_STATS(rx_bad_hdr_len);
+#undef SAVE_PSOCK_STATS
+
+ if (strp->rx_aborted)
+ agg_stats->rx_aborts++;
+ if (strp->rx_interrupted)
+ agg_stats->rx_interrupted++;
+ if (strp->rx_unrecov_intr)
+ agg_stats->rx_unrecov_intr++;
+}
+
+static inline void aggregate_strp_stats(struct strp_aggr_stats *stats,
+ struct strp_aggr_stats *agg_stats)
+{
+#define SAVE_PSOCK_STATS(_stat) (agg_stats->_stat += stats->_stat)
+ SAVE_PSOCK_STATS(rx_msgs);
+ SAVE_PSOCK_STATS(rx_bytes);
+ SAVE_PSOCK_STATS(rx_mem_fail);
+ SAVE_PSOCK_STATS(rx_need_more_hdr);
+ SAVE_PSOCK_STATS(rx_msg_too_big);
+ SAVE_PSOCK_STATS(rx_msg_timeouts);
+ SAVE_PSOCK_STATS(rx_bad_hdr_len);
+ SAVE_PSOCK_STATS(rx_aborts);
+ SAVE_PSOCK_STATS(rx_interrupted);
+ SAVE_PSOCK_STATS(rx_unrecov_intr);
+#undef SAVE_PSOCK_STATS
+
+}
+
+void strp_done(struct strparser *strp);
+void strp_stop(struct strparser *strp);
+void strp_check_rcv(struct strparser *strp);
+int strp_init(struct strparser *strp, struct sock *csk,
+ struct strp_callbacks *cb);
+void strp_tcp_data_ready(struct strparser *strp);
+
+#endif /* __NET_STRPARSER_H_ */
--- /dev/null
+/*
+ * 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");
projects / users / willy / pagecache.git / commitdiff