From 9f9a742db40f95f4dc20fc7293de4ea6ddb24e47 Mon Sep 17 00:00:00 2001 From: "Maciej W. Rozycki" Date: Tue, 9 Oct 2018 23:57:49 +0100 Subject: [PATCH] FDDI: defza: Support capturing outgoing SMT traffic DEC FDDIcontroller 700 (DEFZA) uses a Tx/Rx queue pair to communicate SMT frames with adapter's firmware. Any SMT frame received from the RMC via the Rx queue is queued back by the driver to the SMT Rx queue for the firmware to process. Similarly the firmware uses the SMT Tx queue to supply the driver with SMT frames which are queued back to the Tx queue for the RMC to send to the ring. When a network tap is attached to an FDDI interface handled by `defza' any incoming SMT frames captured are queued to our usual processing of network data received, which in turn delivers them to any listening taps. However the outgoing SMT frames produced by the firmware bypass our network protocol stack and are therefore not delivered to taps. This in turn means that taps are missing a part of network traffic sent by the adapter, which may make it more difficult to track down network problems or do general traffic analysis. Call `dev_queue_xmit_nit' then in the SMT Tx path, having checked that a network tap is attached, with a newly-created `dev_nit_active' helper wrapping the usual condition used in the transmit path. Signed-off-by: Maciej W. Rozycki Signed-off-by: David S. Miller --- drivers/net/fddi/defza.c | 33 +++++++++++++++++++++++++++++++-- include/linux/netdevice.h | 1 + net/core/dev.c | 13 ++++++++++++- 3 files changed, 44 insertions(+), 3 deletions(-) diff --git a/drivers/net/fddi/defza.c b/drivers/net/fddi/defza.c index 7d01b70..3b7f10a 100644 --- a/drivers/net/fddi/defza.c +++ b/drivers/net/fddi/defza.c @@ -797,11 +797,40 @@ static void fza_tx_smt(struct net_device *dev) smt_tx_ptr = fp->mmio + readl_u(&fp->ring_smt_tx[i].buffer); len = readl_u(&fp->ring_smt_tx[i].rmc) & FZA_RING_PBC_MASK; - /* Queue the frame to the RMC transmit ring. */ - if (!netif_queue_stopped(dev)) + if (!netif_queue_stopped(dev)) { + if (dev_nit_active(dev)) { + struct sk_buff *skb; + + /* Length must be a multiple of 4 as only word + * reads are permitted! + */ + skb = fza_alloc_skb_irq(dev, (len + 3) & ~3); + if (!skb) + goto err_no_skb; /* Drop. */ + + skb_data_ptr = (struct fza_buffer_tx *) + skb->data; + + fza_reads(smt_tx_ptr, skb_data_ptr, + (len + 3) & ~3); + skb->dev = dev; + skb_reserve(skb, 3); /* Skip over PRH. */ + skb_put(skb, len - 3); + skb_reset_network_header(skb); + + dev_queue_xmit_nit(skb, dev); + + dev_kfree_skb_irq(skb); + +err_no_skb: + ; + } + + /* Queue the frame to the RMC transmit ring. */ fza_do_xmit((union fza_buffer_txp) { .mmio_ptr = smt_tx_ptr }, len, dev, 1); + } writel_o(FZA_RING_OWN_FZA, &fp->ring_smt_tx[i].own); fp->ring_smt_tx_index = diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 22e4ef7..dc1d9ed 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -3645,6 +3645,7 @@ static __always_inline int ____dev_forward_skb(struct net_device *dev, return 0; } +bool dev_nit_active(struct net_device *dev); void dev_queue_xmit_nit(struct sk_buff *skb, struct net_device *dev); extern int netdev_budget; diff --git a/net/core/dev.c b/net/core/dev.c index a4d39b8..8497fee 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -1976,6 +1976,17 @@ static inline bool skb_loop_sk(struct packet_type *ptype, struct sk_buff *skb) return false; } +/** + * dev_nit_active - return true if any network interface taps are in use + * + * @dev: network device to check for the presence of taps + */ +bool dev_nit_active(struct net_device *dev) +{ + return !list_empty(&ptype_all) || !list_empty(&dev->ptype_all); +} +EXPORT_SYMBOL_GPL(dev_nit_active); + /* * Support routine. Sends outgoing frames to any network * taps currently in use. @@ -3233,7 +3244,7 @@ static int xmit_one(struct sk_buff *skb, struct net_device *dev, unsigned int len; int rc; - if (!list_empty(&ptype_all) || !list_empty(&dev->ptype_all)) + if (dev_nit_active(dev)) dev_queue_xmit_nit(skb, dev); len = skb->len; -- 2.7.4