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-rw-r--r--net/strparser/strparser.c545
1 files changed, 545 insertions, 0 deletions
diff --git a/net/strparser/strparser.c b/net/strparser/strparser.c
new file mode 100644
index 0000000000..8299ceb3e3
--- /dev/null
+++ b/net/strparser/strparser.c
@@ -0,0 +1,545 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Stream Parser
+ *
+ * Copyright (c) 2016 Tom Herbert <tom@herbertland.com>
+ */
+
+#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/export.h>
+#include <linux/init.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;
+
+static inline struct _strp_msg *_strp_msg(struct sk_buff *skb)
+{
+ return (struct _strp_msg *)((void *)skb->cb +
+ offsetof(struct sk_skb_cb, strp));
+}
+
+/* Lower lock held */
+static void strp_abort_strp(struct strparser *strp, int err)
+{
+ /* Unrecoverable error in receive */
+
+ cancel_delayed_work(&strp->msg_timer_work);
+
+ if (strp->stopped)
+ return;
+
+ strp->stopped = 1;
+
+ if (strp->sk) {
+ struct sock *sk = strp->sk;
+
+ /* Report an error on the lower socket */
+ sk->sk_err = -err;
+ sk_error_report(sk);
+ }
+}
+
+static void strp_start_timer(struct strparser *strp, long timeo)
+{
+ if (timeo && timeo != LONG_MAX)
+ mod_delayed_work(strp_wq, &strp->msg_timer_work, timeo);
+}
+
+/* Lower lock held */
+static void strp_parser_err(struct strparser *strp, int err,
+ read_descriptor_t *desc)
+{
+ desc->error = err;
+ kfree_skb(strp->skb_head);
+ strp->skb_head = NULL;
+ strp->cb.abort_parser(strp, err);
+}
+
+static inline int strp_peek_len(struct strparser *strp)
+{
+ if (strp->sk) {
+ struct socket *sock = strp->sk->sk_socket;
+
+ return sock->ops->peek_len(sock);
+ }
+
+ /* If we don't have an associated socket there's nothing to peek.
+ * Return int max to avoid stopping the strparser.
+ */
+
+ return INT_MAX;
+}
+
+/* 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,
+ size_t max_msg_size, long timeo)
+{
+ struct strparser *strp = (struct strparser *)desc->arg.data;
+ struct _strp_msg *stm;
+ struct sk_buff *head, *skb;
+ size_t eaten = 0, cand_len;
+ ssize_t extra;
+ int err;
+ bool cloned_orig = false;
+
+ if (strp->paused)
+ return 0;
+
+ head = strp->skb_head;
+ if (head) {
+ /* Message already in progress */
+ 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.mem_fail);
+ desc->error = -ENOMEM;
+ return 0;
+ }
+ if (!pskb_pull(orig_skb, orig_offset)) {
+ STRP_STATS_INCR(strp->stats.mem_fail);
+ kfree_skb(orig_skb);
+ desc->error = -ENOMEM;
+ return 0;
+ }
+ cloned_orig = true;
+ orig_offset = 0;
+ }
+
+ if (!strp->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.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_for_msg(head);
+ if (!skb) {
+ STRP_STATS_INCR(strp->stats.mem_fail);
+ desc->error = -ENOMEM;
+ return 0;
+ }
+
+ strp->skb_nextp = &head->next;
+ strp->skb_head = skb;
+ head = skb;
+ } else {
+ strp->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.mem_fail);
+ desc->error = -ENOMEM;
+ break;
+ }
+
+ cand_len = orig_len - eaten;
+
+ head = strp->skb_head;
+ if (!head) {
+ head = skb;
+ strp->skb_head = head;
+ /* Will set skb_nextp on next packet if needed */
+ strp->skb_nextp = NULL;
+ stm = _strp_msg(head);
+ memset(stm, 0, sizeof(*stm));
+ stm->strp.offset = orig_offset + eaten;
+ } else {
+ /* Unclone if we are appending to an skb that we
+ * already share a frag_list with.
+ */
+ if (skb_has_frag_list(skb)) {
+ err = skb_unclone(skb, GFP_ATOMIC);
+ if (err) {
+ STRP_STATS_INCR(strp->stats.mem_fail);
+ desc->error = err;
+ break;
+ }
+ }
+
+ stm = _strp_msg(head);
+ *strp->skb_nextp = skb;
+ strp->skb_nextp = &skb->next;
+ head->data_len += skb->len;
+ head->len += skb->len;
+ head->truesize += skb->truesize;
+ }
+
+ if (!stm->strp.full_len) {
+ ssize_t len;
+
+ len = (*strp->cb.parse_msg)(strp, head);
+
+ if (!len) {
+ /* Need more header to determine length */
+ if (!stm->accum_len) {
+ /* Start RX timer for new message */
+ strp_start_timer(strp, timeo);
+ }
+ stm->accum_len += cand_len;
+ eaten += cand_len;
+ STRP_STATS_INCR(strp->stats.need_more_hdr);
+ WARN_ON(eaten != orig_len);
+ break;
+ } else if (len < 0) {
+ if (len == -ESTRPIPE && stm->accum_len) {
+ len = -ENODATA;
+ strp->unrecov_intr = 1;
+ } else {
+ strp->interrupted = 1;
+ }
+ strp_parser_err(strp, len, desc);
+ break;
+ } else if (len > max_msg_size) {
+ /* Message length exceeds maximum allowed */
+ STRP_STATS_INCR(strp->stats.msg_too_big);
+ strp_parser_err(strp, -EMSGSIZE, desc);
+ break;
+ } else if (len <= (ssize_t)head->len -
+ skb->len - stm->strp.offset) {
+ /* Length must be into new skb (and also
+ * greater than zero)
+ */
+ STRP_STATS_INCR(strp->stats.bad_hdr_len);
+ strp_parser_err(strp, -EPROTO, desc);
+ break;
+ }
+
+ stm->strp.full_len = len;
+ }
+
+ extra = (ssize_t)(stm->accum_len + cand_len) -
+ stm->strp.full_len;
+
+ if (extra < 0) {
+ /* Message not complete yet. */
+ if (stm->strp.full_len - stm->accum_len >
+ strp_peek_len(strp)) {
+ /* Don't have the whole message in the socket
+ * buffer. Set strp->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 strp_read_sock.
+ */
+
+ if (!stm->accum_len) {
+ /* Start RX timer for new message */
+ strp_start_timer(strp, timeo);
+ }
+
+ stm->accum_len += cand_len;
+ eaten += cand_len;
+ strp->need_bytes = stm->strp.full_len -
+ stm->accum_len;
+ STRP_STATS_ADD(strp->stats.bytes, cand_len);
+ desc->count = 0; /* Stop reading socket */
+ break;
+ }
+ stm->accum_len += cand_len;
+ eaten += cand_len;
+ WARN_ON(eaten != orig_len);
+ break;
+ }
+
+ /* Positive extra indicates more bytes than needed for the
+ * message
+ */
+
+ WARN_ON(extra > cand_len);
+
+ eaten += (cand_len - extra);
+
+ /* Hurray, we have a new message! */
+ cancel_delayed_work(&strp->msg_timer_work);
+ strp->skb_head = NULL;
+ strp->need_bytes = 0;
+ STRP_STATS_INCR(strp->stats.msgs);
+
+ /* Give skb to upper layer */
+ strp->cb.rcv_msg(strp, head);
+
+ if (unlikely(strp->paused)) {
+ /* Upper layer paused strp */
+ break;
+ }
+ }
+
+ if (cloned_orig)
+ kfree_skb(orig_skb);
+
+ STRP_STATS_ADD(strp->stats.bytes, eaten);
+
+ return eaten;
+}
+
+int strp_process(struct strparser *strp, struct sk_buff *orig_skb,
+ unsigned int orig_offset, size_t orig_len,
+ size_t max_msg_size, long timeo)
+{
+ read_descriptor_t desc; /* Dummy arg to strp_recv */
+
+ desc.arg.data = strp;
+
+ return __strp_recv(&desc, orig_skb, orig_offset, orig_len,
+ max_msg_size, timeo);
+}
+EXPORT_SYMBOL_GPL(strp_process);
+
+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;
+
+ return __strp_recv(desc, orig_skb, orig_offset, orig_len,
+ strp->sk->sk_rcvbuf, strp->sk->sk_rcvtimeo);
+}
+
+static int default_read_sock_done(struct strparser *strp, int err)
+{
+ return err;
+}
+
+/* Called with lock held on lower socket */
+static int strp_read_sock(struct strparser *strp)
+{
+ struct socket *sock = strp->sk->sk_socket;
+ read_descriptor_t desc;
+
+ if (unlikely(!sock || !sock->ops || !sock->ops->read_sock))
+ return -EBUSY;
+
+ 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 read_sock */
+ sock->ops->read_sock(strp->sk, &desc, strp_recv);
+
+ desc.error = strp->cb.read_sock_done(strp, desc.error);
+
+ return desc.error;
+}
+
+/* Lower sock lock held */
+void strp_data_ready(struct strparser *strp)
+{
+ if (unlikely(strp->stopped) || strp->paused)
+ return;
+
+ /* This check is needed to synchronize with do_strp_work.
+ * do_strp_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_nocheck(strp->sk)) {
+ queue_work(strp_wq, &strp->work);
+ return;
+ }
+
+ if (strp->need_bytes) {
+ if (strp_peek_len(strp) < strp->need_bytes)
+ return;
+ }
+
+ if (strp_read_sock(strp) == -ENOMEM)
+ queue_work(strp_wq, &strp->work);
+}
+EXPORT_SYMBOL_GPL(strp_data_ready);
+
+static void do_strp_work(struct strparser *strp)
+{
+ /* We need the read lock to synchronize with strp_data_ready. We
+ * need the socket lock for calling strp_read_sock.
+ */
+ strp->cb.lock(strp);
+
+ if (unlikely(strp->stopped))
+ goto out;
+
+ if (strp->paused)
+ goto out;
+
+ if (strp_read_sock(strp) == -ENOMEM)
+ queue_work(strp_wq, &strp->work);
+
+out:
+ strp->cb.unlock(strp);
+}
+
+static void strp_work(struct work_struct *w)
+{
+ do_strp_work(container_of(w, struct strparser, work));
+}
+
+static void strp_msg_timeout(struct work_struct *w)
+{
+ struct strparser *strp = container_of(w, struct strparser,
+ msg_timer_work.work);
+
+ /* Message assembly timed out */
+ STRP_STATS_INCR(strp->stats.msg_timeouts);
+ strp->cb.lock(strp);
+ strp->cb.abort_parser(strp, -ETIMEDOUT);
+ strp->cb.unlock(strp);
+}
+
+static void strp_sock_lock(struct strparser *strp)
+{
+ lock_sock(strp->sk);
+}
+
+static void strp_sock_unlock(struct strparser *strp)
+{
+ release_sock(strp->sk);
+}
+
+int strp_init(struct strparser *strp, struct sock *sk,
+ const struct strp_callbacks *cb)
+{
+
+ if (!cb || !cb->rcv_msg || !cb->parse_msg)
+ return -EINVAL;
+
+ /* The sk (sock) arg determines the mode of the stream parser.
+ *
+ * If the sock is set then the strparser is in receive callback mode.
+ * The upper layer calls strp_data_ready to kick receive processing
+ * and strparser calls the read_sock function on the socket to
+ * get packets.
+ *
+ * If the sock is not set then the strparser is in general mode.
+ * The upper layer calls strp_process for each skb to be parsed.
+ */
+
+ if (!sk) {
+ if (!cb->lock || !cb->unlock)
+ return -EINVAL;
+ }
+
+ memset(strp, 0, sizeof(*strp));
+
+ strp->sk = sk;
+
+ strp->cb.lock = cb->lock ? : strp_sock_lock;
+ strp->cb.unlock = cb->unlock ? : strp_sock_unlock;
+ 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_strp;
+
+ INIT_DELAYED_WORK(&strp->msg_timer_work, strp_msg_timeout);
+ INIT_WORK(&strp->work, strp_work);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(strp_init);
+
+/* Sock process lock held (lock_sock) */
+void __strp_unpause(struct strparser *strp)
+{
+ strp->paused = 0;
+
+ if (strp->need_bytes) {
+ if (strp_peek_len(strp) < strp->need_bytes)
+ return;
+ }
+ strp_read_sock(strp);
+}
+EXPORT_SYMBOL_GPL(__strp_unpause);
+
+void strp_unpause(struct strparser *strp)
+{
+ strp->paused = 0;
+
+ /* Sync setting paused with RX work */
+ smp_mb();
+
+ queue_work(strp_wq, &strp->work);
+}
+EXPORT_SYMBOL_GPL(strp_unpause);
+
+/* strp must already be stopped so that strp_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->stopped);
+
+ cancel_delayed_work_sync(&strp->msg_timer_work);
+ cancel_work_sync(&strp->work);
+
+ if (strp->skb_head) {
+ kfree_skb(strp->skb_head);
+ strp->skb_head = NULL;
+ }
+}
+EXPORT_SYMBOL_GPL(strp_done);
+
+void strp_stop(struct strparser *strp)
+{
+ strp->stopped = 1;
+}
+EXPORT_SYMBOL_GPL(strp_stop);
+
+void strp_check_rcv(struct strparser *strp)
+{
+ queue_work(strp_wq, &strp->work);
+}
+EXPORT_SYMBOL_GPL(strp_check_rcv);
+
+static int __init strp_dev_init(void)
+{
+ BUILD_BUG_ON(sizeof(struct sk_skb_cb) >
+ sizeof_field(struct sk_buff, cb));
+
+ strp_wq = create_singlethread_workqueue("kstrp");
+ if (unlikely(!strp_wq))
+ return -ENOMEM;
+
+ return 0;
+}
+device_initcall(strp_dev_init);
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