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);