xen-netback: better names for thresholds
This patch only changes some names to avoid confusion. In this patch we have: MAX_SKB_SLOTS_DEFAULT -> FATAL_SKB_SLOTS_DEFAULT max_skb_slots -> fatal_skb_slots #define XEN_NETBK_LEGACY_SLOTS_MAX XEN_NETIF_NR_SLOTS_MIN The fatal_skb_slots is the threshold to determine whether a packet is malicious. XEN_NETBK_LEGACY_SLOTS_MAX is the maximum slots a valid packet can have at this point. It is defined to be XEN_NETIF_NR_SLOTS_MIN because that's guaranteed to be supported by all backends. Suggested-by: Ian Campbell <ian.campbell@citrix.com> Signed-off-by: Wei Liu <wei.liu2@citrix.com> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Wei Liu
David S. Miller
Родитель
59ccb4ebbc
Коммит
376414945d
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@ -51,9 +51,17 @@
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* This is the maximum slots a skb can have. If a guest sends a skb
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* which exceeds this limit it is considered malicious.
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*/
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#define MAX_SKB_SLOTS_DEFAULT 20
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static unsigned int max_skb_slots = MAX_SKB_SLOTS_DEFAULT;
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module_param(max_skb_slots, uint, 0444);
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#define FATAL_SKB_SLOTS_DEFAULT 20
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static unsigned int fatal_skb_slots = FATAL_SKB_SLOTS_DEFAULT;
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module_param(fatal_skb_slots, uint, 0444);
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/*
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* To avoid confusion, we define XEN_NETBK_LEGACY_SLOTS_MAX indicating
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* the maximum slots a valid packet can use. Now this value is defined
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* to be XEN_NETIF_NR_SLOTS_MIN, which is supposed to be supported by
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* all backend.
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*/
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#define XEN_NETBK_LEGACY_SLOTS_MAX XEN_NETIF_NR_SLOTS_MIN
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typedef unsigned int pending_ring_idx_t;
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#define INVALID_PENDING_RING_IDX (~0U)
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@ -953,25 +961,26 @@ static int netbk_count_requests(struct xenvif *vif,
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/* This guest is really using too many slots and
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* considered malicious.
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*/
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if (unlikely(slots >= max_skb_slots)) {
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if (unlikely(slots >= fatal_skb_slots)) {
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netdev_err(vif->dev,
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"Malicious frontend using %d slots, threshold %u\n",
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slots, max_skb_slots);
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slots, fatal_skb_slots);
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netbk_fatal_tx_err(vif);
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return -E2BIG;
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}
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/* Xen network protocol had implicit dependency on
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* MAX_SKB_FRAGS. XEN_NETIF_NR_SLOTS_MIN is set to the
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* historical MAX_SKB_FRAGS value 18 to honor the same
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* behavior as before. Any packet using more than 18
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* slots but less than max_skb_slots slots is dropped
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* MAX_SKB_FRAGS. XEN_NETBK_LEGACY_SLOTS_MAX is set to
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* the historical MAX_SKB_FRAGS value 18 to honor the
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* same behavior as before. Any packet using more than
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* 18 slots but less than fatal_skb_slots slots is
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* dropped
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*/
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if (!drop_err && slots >= XEN_NETIF_NR_SLOTS_MIN) {
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if (!drop_err && slots >= XEN_NETBK_LEGACY_SLOTS_MAX) {
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if (net_ratelimit())
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netdev_dbg(vif->dev,
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"Too many slots (%d) exceeding limit (%d), dropping packet\n",
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slots, XEN_NETIF_NR_SLOTS_MIN);
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slots, XEN_NETBK_LEGACY_SLOTS_MAX);
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drop_err = -E2BIG;
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}
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@ -1053,7 +1062,7 @@ static struct gnttab_copy *xen_netbk_get_requests(struct xen_netbk *netbk,
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struct pending_tx_info *first = NULL;
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/* At this point shinfo->nr_frags is in fact the number of
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* slots, which can be as large as XEN_NETIF_NR_SLOTS_MIN.
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* slots, which can be as large as XEN_NETBK_LEGACY_SLOTS_MAX.
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*/
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nr_slots = shinfo->nr_frags;
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@ -1415,12 +1424,12 @@ static unsigned xen_netbk_tx_build_gops(struct xen_netbk *netbk)
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struct sk_buff *skb;
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int ret;
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while ((nr_pending_reqs(netbk) + XEN_NETIF_NR_SLOTS_MIN
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while ((nr_pending_reqs(netbk) + XEN_NETBK_LEGACY_SLOTS_MAX
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< MAX_PENDING_REQS) &&
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!list_empty(&netbk->net_schedule_list)) {
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struct xenvif *vif;
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struct xen_netif_tx_request txreq;
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struct xen_netif_tx_request txfrags[XEN_NETIF_NR_SLOTS_MIN];
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struct xen_netif_tx_request txfrags[XEN_NETBK_LEGACY_SLOTS_MAX];
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struct page *page;
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struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX-1];
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u16 pending_idx;
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@ -1508,7 +1517,7 @@ static unsigned xen_netbk_tx_build_gops(struct xen_netbk *netbk)
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pending_idx = netbk->pending_ring[index];
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data_len = (txreq.size > PKT_PROT_LEN &&
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ret < XEN_NETIF_NR_SLOTS_MIN) ?
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ret < XEN_NETBK_LEGACY_SLOTS_MAX) ?
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PKT_PROT_LEN : txreq.size;
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skb = alloc_skb(data_len + NET_SKB_PAD + NET_IP_ALIGN,
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@ -1787,7 +1796,7 @@ static inline int rx_work_todo(struct xen_netbk *netbk)
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static inline int tx_work_todo(struct xen_netbk *netbk)
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{
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if ((nr_pending_reqs(netbk) + XEN_NETIF_NR_SLOTS_MIN
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if ((nr_pending_reqs(netbk) + XEN_NETBK_LEGACY_SLOTS_MAX
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< MAX_PENDING_REQS) &&
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!list_empty(&netbk->net_schedule_list))
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return 1;
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@ -1872,11 +1881,11 @@ static int __init netback_init(void)
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if (!xen_domain())
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return -ENODEV;
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if (max_skb_slots < XEN_NETIF_NR_SLOTS_MIN) {
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if (fatal_skb_slots < XEN_NETBK_LEGACY_SLOTS_MAX) {
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printk(KERN_INFO
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"xen-netback: max_skb_slots too small (%d), bump it to XEN_NETIF_NR_SLOTS_MIN (%d)\n",
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max_skb_slots, XEN_NETIF_NR_SLOTS_MIN);
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max_skb_slots = XEN_NETIF_NR_SLOTS_MIN;
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"xen-netback: fatal_skb_slots too small (%d), bump it to XEN_NETBK_LEGACY_SLOTS_MAX (%d)\n",
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fatal_skb_slots, XEN_NETBK_LEGACY_SLOTS_MAX);
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fatal_skb_slots = XEN_NETBK_LEGACY_SLOTS_MAX;
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}
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xen_netbk_group_nr = num_online_cpus();
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