strparser: Generalize strparser

Generalize strparser from more than just being used in conjunction
with read_sock. strparser will also be used in the send path with
zero proxy. The primary change is to create strp_process function
that performs the critical processing on skbs. The documentation
is also updated to reflect the new uses.

Signed-off-by: Tom Herbert <tom@quantonium.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 187 insertions, 126 deletions

diff --git a/net/strparser/strparser.c b/net/strparser/strparser.c
index b5c279b22680..0d18fbc6f870 100644
--- a/net/strparser/strparser.c
+++ b/net/strparser/strparser.c
@@ -29,44 +29,46 @@
 
 static struct workqueue_struct *strp_wq;
 
-struct _strp_rx_msg {
-	/* Internal cb structure. struct strp_rx_msg must be first for passing
+struct _strp_msg {
+	/* Internal cb structure. struct strp_msg must be first for passing
 	 * to upper layer.
 	 */
-	struct strp_rx_msg strp;
+	struct strp_msg strp;
 	int accum_len;
 	int early_eaten;
 };
 
-static inline struct _strp_rx_msg *_strp_rx_msg(struct sk_buff *skb)
+static inline struct _strp_msg *_strp_msg(struct sk_buff *skb)
 {
-	return (struct _strp_rx_msg *)((void *)skb->cb +
+	return (struct _strp_msg *)((void *)skb->cb +
 		offsetof(struct qdisc_skb_cb, data));
 }
 
 /* Lower lock held */
-static void strp_abort_rx_strp(struct strparser *strp, int err)
+static void strp_abort_strp(struct strparser *strp, int err)
 {
-	struct sock *csk = strp->sk;
-
 	/* Unrecoverable error in receive */
 
-	del_timer(&strp->rx_msg_timer);
+	del_timer(&strp->msg_timer);
 
-	if (strp->rx_stopped)
+	if (strp->stopped)
 		return;
 
-	strp->rx_stopped = 1;
+	strp->stopped = 1;
+
+	if (strp->sk) {
+		struct sock *sk = strp->sk;
 
-	/* Report an error on the lower socket */
-	csk->sk_err = err;
-	csk->sk_error_report(csk);
+		/* Report an error on the lower socket */
+		sk->sk_err = err;
+		sk->sk_error_report(sk);
+	}
 }
 
-static void strp_start_rx_timer(struct strparser *strp)
+static void strp_start_timer(struct strparser *strp, long timeo)
 {
-	if (strp->sk->sk_rcvtimeo)
-		mod_timer(&strp->rx_msg_timer, strp->sk->sk_rcvtimeo);
+	if (timeo)
+		mod_timer(&strp->msg_timer, timeo);
 }
 
 /* Lower lock held */
@@ -74,46 +76,55 @@ 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;
+	kfree_skb(strp->skb_head);
+	strp->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;
+	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 sock->ops->peek_len(sock);
+	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)
+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_rx_msg *rxm;
+	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->rx_paused)
+	if (strp->paused)
 		return 0;
 
-	head = strp->rx_skb_head;
+	head = strp->skb_head;
 	if (head) {
 		/* Message already in progress */
 
-		rxm = _strp_rx_msg(head);
-		if (unlikely(rxm->early_eaten)) {
+		stm = _strp_msg(head);
+		if (unlikely(stm->early_eaten)) {
 			/* Already some number of bytes on the receive sock
-			 * data saved in rx_skb_head, just indicate they
+			 * data saved in skb_head, just indicate they
 			 * are consumed.
 			 */
-			eaten = orig_len <= rxm->early_eaten ?
-				orig_len : rxm->early_eaten;
-			rxm->early_eaten -= eaten;
+			eaten = orig_len <= stm->early_eaten ?
+				orig_len : stm->early_eaten;
+			stm->early_eaten -= eaten;
 
 			return eaten;
 		}
@@ -126,12 +137,12 @@ static int strp_recv(read_descriptor_t *desc, struct sk_buff *orig_skb,
 			 */
 			orig_skb = skb_clone(orig_skb, GFP_ATOMIC);
 			if (!orig_skb) {
-				STRP_STATS_INCR(strp->stats.rx_mem_fail);
+				STRP_STATS_INCR(strp->stats.mem_fail);
 				desc->error = -ENOMEM;
 				return 0;
 			}
 			if (!pskb_pull(orig_skb, orig_offset)) {
-				STRP_STATS_INCR(strp->stats.rx_mem_fail);
+				STRP_STATS_INCR(strp->stats.mem_fail);
 				kfree_skb(orig_skb);
 				desc->error = -ENOMEM;
 				return 0;
@@ -140,13 +151,13 @@ static int strp_recv(read_descriptor_t *desc, struct sk_buff *orig_skb,
 			orig_offset = 0;
 		}
 
-		if (!strp->rx_skb_nextp) {
+		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.rx_mem_fail);
+				STRP_STATS_INCR(strp->stats.mem_fail);
 				desc->error = err;
 				return 0;
 			}
@@ -165,20 +176,20 @@ static int strp_recv(read_descriptor_t *desc, struct sk_buff *orig_skb,
 
 				skb = alloc_skb(0, GFP_ATOMIC);
 				if (!skb) {
-					STRP_STATS_INCR(strp->stats.rx_mem_fail);
+					STRP_STATS_INCR(strp->stats.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;
+				*_strp_msg(skb) = *_strp_msg(head);
+				strp->skb_nextp = &head->next;
 				skb_shinfo(skb)->frag_list = head;
-				strp->rx_skb_head = skb;
+				strp->skb_head = skb;
 				head = skb;
 			} else {
-				strp->rx_skb_nextp =
+				strp->skb_nextp =
 				    &skb_shinfo(head)->frag_list;
 			}
 		}
@@ -188,112 +199,112 @@ static int strp_recv(read_descriptor_t *desc, struct sk_buff *orig_skb,
 		/* Always clone since we will consume something */
 		skb = skb_clone(orig_skb, GFP_ATOMIC);
 		if (!skb) {
-			STRP_STATS_INCR(strp->stats.rx_mem_fail);
+			STRP_STATS_INCR(strp->stats.mem_fail);
 			desc->error = -ENOMEM;
 			break;
 		}
 
 		cand_len = orig_len - eaten;
 
-		head = strp->rx_skb_head;
+		head = strp->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;
+			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 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);
+				STRP_STATS_INCR(strp->stats.mem_fail);
 				desc->error = err;
 				break;
 			}
 
-			rxm = _strp_rx_msg(head);
-			*strp->rx_skb_nextp = skb;
-			strp->rx_skb_nextp = &skb->next;
+			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 (!rxm->strp.full_len) {
+		if (!stm->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) {
+				if (!stm->accum_len) {
 					/* Start RX timer for new message */
-					strp_start_rx_timer(strp);
+					strp_start_timer(strp, timeo);
 				}
-				rxm->accum_len += cand_len;
+				stm->accum_len += cand_len;
 				eaten += cand_len;
-				STRP_STATS_INCR(strp->stats.rx_need_more_hdr);
+				STRP_STATS_INCR(strp->stats.need_more_hdr);
 				WARN_ON(eaten != orig_len);
 				break;
 			} else if (len < 0) {
-				if (len == -ESTRPIPE && rxm->accum_len) {
+				if (len == -ESTRPIPE && stm->accum_len) {
 					len = -ENODATA;
-					strp->rx_unrecov_intr = 1;
+					strp->unrecov_intr = 1;
 				} else {
-					strp->rx_interrupted = 1;
+					strp->interrupted = 1;
 				}
 				strp_parser_err(strp, len, desc);
 				break;
-			} else if (len > strp->sk->sk_rcvbuf) {
+			} else if (len > max_msg_size) {
 				/* Message length exceeds maximum allowed */
-				STRP_STATS_INCR(strp->stats.rx_msg_too_big);
+				STRP_STATS_INCR(strp->stats.msg_too_big);
 				strp_parser_err(strp, -EMSGSIZE, desc);
 				break;
 			} else if (len <= (ssize_t)head->len -
-					  skb->len - rxm->strp.offset) {
+					  skb->len - stm->strp.offset) {
 				/* Length must be into new skb (and also
 				 * greater than zero)
 				 */
-				STRP_STATS_INCR(strp->stats.rx_bad_hdr_len);
+				STRP_STATS_INCR(strp->stats.bad_hdr_len);
 				strp_parser_err(strp, -EPROTO, desc);
 				break;
 			}
 
-			rxm->strp.full_len = len;
+			stm->strp.full_len = len;
 		}
 
-		extra = (ssize_t)(rxm->accum_len + cand_len) -
-			rxm->strp.full_len;
+		extra = (ssize_t)(stm->accum_len + cand_len) -
+			stm->strp.full_len;
 
 		if (extra < 0) {
 			/* Message not complete yet. */
-			if (rxm->strp.full_len - rxm->accum_len >
+			if (stm->strp.full_len - stm->accum_len >
 			    strp_peek_len(strp)) {
-				/* Don't have the whole messages in the socket
-				 * buffer. Set strp->rx_need_bytes to wait for
+				/* 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 (!rxm->accum_len) {
+				if (!stm->accum_len) {
 					/* Start RX timer for new message */
-					strp_start_rx_timer(strp);
+					strp_start_timer(strp, timeo);
 				}
 
-				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);
+				strp->need_bytes = stm->strp.full_len -
+						       stm->accum_len;
+				stm->accum_len += cand_len;
+				stm->early_eaten = cand_len;
+				STRP_STATS_ADD(strp->stats.bytes, cand_len);
 				desc->count = 0; /* Stop reading socket */
 				break;
 			}
-			rxm->accum_len += cand_len;
+			stm->accum_len += cand_len;
 			eaten += cand_len;
 			WARN_ON(eaten != orig_len);
 			break;
@@ -308,14 +319,14 @@ static int strp_recv(read_descriptor_t *desc, struct sk_buff *orig_skb,
 		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);
+		del_timer(&strp->msg_timer);
+		strp->skb_head = NULL;
+		STRP_STATS_INCR(strp->stats.msgs);
 
 		/* Give skb to upper layer */
 		strp->cb.rcv_msg(strp, head);
 
-		if (unlikely(strp->rx_paused)) {
+		if (unlikely(strp->paused)) {
 			/* Upper layer paused strp */
 			break;
 		}
@@ -324,11 +335,33 @@ static int strp_recv(read_descriptor_t *desc, struct sk_buff *orig_skb,
 	if (cloned_orig)
 		kfree_skb(orig_skb);
 
-	STRP_STATS_ADD(strp->stats.rx_bytes, eaten);
+	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;
@@ -355,101 +388,129 @@ static int strp_read_sock(struct strparser *strp)
 /* Lower sock lock held */
 void strp_data_ready(struct strparser *strp)
 {
-	if (unlikely(strp->rx_stopped))
+	if (unlikely(strp->stopped))
 		return;
 
-	/* This check is needed to synchronize with do_strp_rx_work.
-	 * do_strp_rx_work acquires a process lock (lock_sock) whereas
+	/* 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(strp->sk)) {
-		queue_work(strp_wq, &strp->rx_work);
+		queue_work(strp_wq, &strp->work);
 		return;
 	}
 
-	if (strp->rx_paused)
+	if (strp->paused)
 		return;
 
-	if (strp->rx_need_bytes) {
-		if (strp_peek_len(strp) >= strp->rx_need_bytes)
-			strp->rx_need_bytes = 0;
+	if (strp->need_bytes) {
+		if (strp_peek_len(strp) >= strp->need_bytes)
+			strp->need_bytes = 0;
 		else
 			return;
 	}
 
 	if (strp_read_sock(strp) == -ENOMEM)
-		queue_work(strp_wq, &strp->rx_work);
+		queue_work(strp_wq, &strp->work);
 }
 EXPORT_SYMBOL_GPL(strp_data_ready);
 
-static void do_strp_rx_work(struct strparser *strp)
+static void do_strp_work(struct strparser *strp)
 {
 	read_descriptor_t rd_desc;
-	struct sock *csk = strp->sk;
 
 	/* We need the read lock to synchronize with strp_data_ready. We
 	 * need the socket lock for calling strp_read_sock.
 	 */
-	lock_sock(csk);
+	strp->cb.lock(strp);
 
-	if (unlikely(strp->rx_stopped))
+	if (unlikely(strp->stopped))
 		goto out;
 
-	if (strp->rx_paused)
+	if (strp->paused)
 		goto out;
 
 	rd_desc.arg.data = strp;
 
 	if (strp_read_sock(strp) == -ENOMEM)
-		queue_work(strp_wq, &strp->rx_work);
+		queue_work(strp_wq, &strp->work);
 
 out:
-	release_sock(csk);
+	strp->cb.unlock(strp);
 }
 
-static void strp_rx_work(struct work_struct *w)
+static void strp_work(struct work_struct *w)
 {
-	do_strp_rx_work(container_of(w, struct strparser, rx_work));
+	do_strp_work(container_of(w, struct strparser, work));
 }
 
-static void strp_rx_msg_timeout(unsigned long arg)
+static void strp_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_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 *csk,
+int strp_init(struct strparser *strp, struct sock *sk,
 	      struct strp_callbacks *cb)
 {
-	struct socket *sock = csk->sk_socket;
 
 	if (!cb || !cb->rcv_msg || !cb->parse_msg)
 		return -EINVAL;
 
-	if (!sock->ops->read_sock || !sock->ops->peek_len)
-		return -EAFNOSUPPORT;
+	/* 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.
+	 */
 
-	memset(strp, 0, sizeof(*strp));
+	if (sk) {
+		struct socket *sock = sk->sk_socket;
 
-	strp->sk = csk;
+		if (!sock->ops->read_sock || !sock->ops->peek_len)
+			return -EAFNOSUPPORT;
+	} else {
+		if (!cb->lock || !cb->unlock)
+			return -EINVAL;
+	}
 
-	setup_timer(&strp->rx_msg_timer, strp_rx_msg_timeout,
-		    (unsigned long)strp);
+	memset(strp, 0, sizeof(*strp));
 
-	INIT_WORK(&strp->rx_work, strp_rx_work);
+	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_rx_strp;
+	strp->cb.abort_parser = cb->abort_parser ? : strp_abort_strp;
+
+	setup_timer(&strp->msg_timer, strp_msg_timeout,
+		    (unsigned long)strp);
+
+	INIT_WORK(&strp->work, strp_work);
 
 	return 0;
 }
@@ -457,12 +518,12 @@ EXPORT_SYMBOL_GPL(strp_init);
 
 void strp_unpause(struct strparser *strp)
 {
-	strp->rx_paused = 0;
+	strp->paused = 0;
 
-	/* Sync setting rx_paused with RX work */
+	/* Sync setting paused with RX work */
 	smp_mb();
 
-	queue_work(strp_wq, &strp->rx_work);
+	queue_work(strp_wq, &strp->work);
 }
 EXPORT_SYMBOL_GPL(strp_unpause);
 
@@ -471,27 +532,27 @@ EXPORT_SYMBOL_GPL(strp_unpause);
  */
 void strp_done(struct strparser *strp)
 {
-	WARN_ON(!strp->rx_stopped);
+	WARN_ON(!strp->stopped);
 
-	del_timer_sync(&strp->rx_msg_timer);
-	cancel_work_sync(&strp->rx_work);
+	del_timer_sync(&strp->msg_timer);
+	cancel_work_sync(&strp->work);
 
-	if (strp->rx_skb_head) {
-		kfree_skb(strp->rx_skb_head);
-		strp->rx_skb_head = NULL;
+	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->rx_stopped = 1;
+	strp->stopped = 1;
 }
 EXPORT_SYMBOL_GPL(strp_stop);
 
 void strp_check_rcv(struct strparser *strp)
 {
-	queue_work(strp_wq, &strp->rx_work);
+	queue_work(strp_wq, &strp->work);
 }
 EXPORT_SYMBOL_GPL(strp_check_rcv);