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Message-ID: <150696033983.24152.15353410729490048581.stgit@firesoul>
Date: Mon, 02 Oct 2017 18:05:39 +0200
From: Jesper Dangaard Brouer <brouer@...hat.com>
To: netdev@...r.kernel.org
Cc: jakub.kicinski@...ronome.com,
"Michael S. Tsirkin" <mst@...hat.com>, pavel.odintsov@...il.com,
Jason Wang <jasowang@...hat.com>, mchan@...adcom.com,
John Fastabend <john.fastabend@...il.com>,
peter.waskiewicz.jr@...el.com,
Jesper Dangaard Brouer <brouer@...hat.com>,
Daniel Borkmann <borkmann@...earbox.net>,
Alexei Starovoitov <alexei.starovoitov@...il.com>,
Andy Gospodarek <andy@...yhouse.net>
Subject: [net-next V3 PATCH 5/5] samples/bpf: add cpumap sample program
xdp_redirect_cpu
This sample program show how to use cpumap and the associated
tracepoints.
It provides command line stats, which shows how the XDP-RX process,
cpumap-enqueue and cpumap kthread dequeue is cooperating on a per CPU
basis. It also utilize the xdp_exception and xdp_redirect_err
transpoints to allow users quickly to identify setup issues.
One issue with ixgbe driver is that the driver reset the link when
loading XDP. This reset the procfs smp_affinity settings. Thus,
after loading the program, these must be reconfigured. The easiest
workaround it to reduce the RX-queue to e.g. two via:
# ethtool --set-channels ixgbe1 combined 2
And then add CPUs above 0 and 1, like:
# xdp_redirect_cpu --dev ixgbe1 --prog 2 --cpu 2 --cpu 3 --cpu 4
Another issue with ixgbe is that the page recycle mechanism is tied to
the RX-ring size. And the default setting of 512 elements is too
small. This is the same issue with regular devmap XDP_REDIRECT.
To overcome this I've been using 1024 rx-ring size:
# ethtool -G ixgbe1 rx 1024 tx 1024
V3:
- whitespace cleanups
- bpf tracepoint cannot access top part of struct
Signed-off-by: Jesper Dangaard Brouer <brouer@...hat.com>
---
samples/bpf/Makefile | 4
samples/bpf/xdp_redirect_cpu_kern.c | 619 +++++++++++++++++++++++++++++++++
samples/bpf/xdp_redirect_cpu_user.c | 647 +++++++++++++++++++++++++++++++++++
3 files changed, 1270 insertions(+)
create mode 100644 samples/bpf/xdp_redirect_cpu_kern.c
create mode 100644 samples/bpf/xdp_redirect_cpu_user.c
diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index ebc2ad69b62c..52c4dab2c153 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -39,6 +39,7 @@ hostprogs-y += per_socket_stats_example
hostprogs-y += load_sock_ops
hostprogs-y += xdp_redirect
hostprogs-y += xdp_redirect_map
+hostprogs-y += xdp_redirect_cpu
hostprogs-y += xdp_monitor
hostprogs-y += syscall_tp
@@ -84,6 +85,7 @@ test_map_in_map-objs := bpf_load.o $(LIBBPF) test_map_in_map_user.o
per_socket_stats_example-objs := $(LIBBPF) cookie_uid_helper_example.o
xdp_redirect-objs := bpf_load.o $(LIBBPF) xdp_redirect_user.o
xdp_redirect_map-objs := bpf_load.o $(LIBBPF) xdp_redirect_map_user.o
+xdp_redirect_cpu-objs := bpf_load.o $(LIBBPF) xdp_redirect_cpu_user.o
xdp_monitor-objs := bpf_load.o $(LIBBPF) xdp_monitor_user.o
syscall_tp-objs := bpf_load.o $(LIBBPF) syscall_tp_user.o
@@ -129,6 +131,7 @@ always += tcp_iw_kern.o
always += tcp_clamp_kern.o
always += xdp_redirect_kern.o
always += xdp_redirect_map_kern.o
+always += xdp_redirect_cpu_kern.o
always += xdp_monitor_kern.o
always += syscall_tp_kern.o
@@ -169,6 +172,7 @@ HOSTLOADLIBES_xdp_tx_iptunnel += -lelf
HOSTLOADLIBES_test_map_in_map += -lelf
HOSTLOADLIBES_xdp_redirect += -lelf
HOSTLOADLIBES_xdp_redirect_map += -lelf
+HOSTLOADLIBES_xdp_redirect_cpu += -lelf
HOSTLOADLIBES_xdp_monitor += -lelf
HOSTLOADLIBES_syscall_tp += -lelf
diff --git a/samples/bpf/xdp_redirect_cpu_kern.c b/samples/bpf/xdp_redirect_cpu_kern.c
new file mode 100644
index 000000000000..fd1f55cb5079
--- /dev/null
+++ b/samples/bpf/xdp_redirect_cpu_kern.c
@@ -0,0 +1,619 @@
+/* XDP redirect to CPUs via cpumap (BPF_MAP_TYPE_CPUMAP)
+ *
+ * GPLv2, Copyright(c) 2017 Jesper Dangaard Brouer, Red Hat, Inc.
+ */
+#include <uapi/linux/if_ether.h>
+#include <uapi/linux/if_packet.h>
+#include <uapi/linux/if_vlan.h>
+#include <uapi/linux/ip.h>
+#include <uapi/linux/ipv6.h>
+#include <uapi/linux/in.h>
+#include <uapi/linux/tcp.h>
+#include <uapi/linux/udp.h>
+
+#include <uapi/linux/bpf.h>
+#include "bpf_helpers.h"
+
+#define MAX_CPUS 12 /* WARNING - sync with _user.c */
+
+/* Special map type that can XDP_REDIRECT frames to another CPU */
+struct bpf_map_def SEC("maps") cpu_map = {
+ .type = BPF_MAP_TYPE_CPUMAP,
+ .key_size = sizeof(u32),
+ .value_size = sizeof(u32),
+ .max_entries = MAX_CPUS,
+};
+
+/* Common stats data record to keep userspace more simple */
+struct datarec {
+ __u64 processed;
+ __u64 dropped;
+ __u64 issue;
+};
+
+/* Count RX packets, as XDP bpf_prog doesn't get direct TX-success
+ * feedback. Redirect TX errors can be caught via a tracepoint.
+ */
+struct bpf_map_def SEC("maps") rx_cnt = {
+ .type = BPF_MAP_TYPE_PERCPU_ARRAY,
+ .key_size = sizeof(u32),
+ .value_size = sizeof(struct datarec),
+ .max_entries = 1,
+};
+
+/* Used by trace point */
+struct bpf_map_def SEC("maps") redirect_err_cnt = {
+ .type = BPF_MAP_TYPE_PERCPU_ARRAY,
+ .key_size = sizeof(u32),
+ .value_size = sizeof(struct datarec),
+ .max_entries = 2,
+ /* TODO: have entries for all possible errno's */
+};
+
+/* Used by trace point */
+struct bpf_map_def SEC("maps") cpumap_enqueue_cnt = {
+ .type = BPF_MAP_TYPE_PERCPU_ARRAY,
+ .key_size = sizeof(u32),
+ .value_size = sizeof(struct datarec),
+ .max_entries = MAX_CPUS,
+};
+
+/* Used by trace point */
+struct bpf_map_def SEC("maps") cpumap_kthread_cnt = {
+ .type = BPF_MAP_TYPE_PERCPU_ARRAY,
+ .key_size = sizeof(u32),
+ .value_size = sizeof(struct datarec),
+ .max_entries = 1,
+};
+
+/* Set of maps controlling available CPU, and for iterating through
+ * selectable redirect CPUs.
+ */
+struct bpf_map_def SEC("maps") cpus_available = {
+ .type = BPF_MAP_TYPE_ARRAY,
+ .key_size = sizeof(u32),
+ .value_size = sizeof(u32),
+ .max_entries = MAX_CPUS,
+};
+struct bpf_map_def SEC("maps") cpus_count = {
+ .type = BPF_MAP_TYPE_ARRAY,
+ .key_size = sizeof(u32),
+ .value_size = sizeof(u32),
+ .max_entries = 1,
+};
+struct bpf_map_def SEC("maps") cpus_iterator = {
+ .type = BPF_MAP_TYPE_PERCPU_ARRAY,
+ .key_size = sizeof(u32),
+ .value_size = sizeof(u32),
+ .max_entries = 1,
+};
+
+/* Used by trace point */
+struct bpf_map_def SEC("maps") exception_cnt = {
+ .type = BPF_MAP_TYPE_PERCPU_ARRAY,
+ .key_size = sizeof(u32),
+ .value_size = sizeof(struct datarec),
+ .max_entries = 1,
+};
+
+/* Helper parse functions */
+
+/* Parse Ethernet layer 2, extract network layer 3 offset and protocol
+ *
+ * Returns false on error and non-supported ether-type
+ */
+struct vlan_hdr {
+ __be16 h_vlan_TCI;
+ __be16 h_vlan_encapsulated_proto;
+};
+
+static __always_inline
+bool parse_eth(struct ethhdr *eth, void *data_end,
+ u16 *eth_proto, u64 *l3_offset)
+{
+ u16 eth_type;
+ u64 offset;
+
+ offset = sizeof(*eth);
+ if ((void *)eth + offset > data_end)
+ return false;
+
+ eth_type = eth->h_proto;
+
+ /* Skip non 802.3 Ethertypes */
+ if (unlikely(ntohs(eth_type) < ETH_P_802_3_MIN))
+ return false;
+
+ /* Handle VLAN tagged packet */
+ if (eth_type == htons(ETH_P_8021Q) || eth_type == htons(ETH_P_8021AD)) {
+ struct vlan_hdr *vlan_hdr;
+
+ vlan_hdr = (void *)eth + offset;
+ offset += sizeof(*vlan_hdr);
+ if ((void *)eth + offset > data_end)
+ return false;
+ eth_type = vlan_hdr->h_vlan_encapsulated_proto;
+ }
+ /* TODO: Handle double VLAN tagged packet */
+
+ *eth_proto = ntohs(eth_type);
+ *l3_offset = offset;
+ return true;
+}
+
+static __always_inline
+u16 get_dest_port_ipv4_udp(struct xdp_md *ctx, u64 nh_off)
+{
+ void *data_end = (void *)(long)ctx->data_end;
+ void *data = (void *)(long)ctx->data;
+ struct iphdr *iph = data + nh_off;
+ struct udphdr *udph;
+ u16 dport;
+
+ if (iph + 1 > data_end)
+ return 0;
+ if (!(iph->protocol == IPPROTO_UDP))
+ return 0;
+
+ udph = (void *)(iph + 1);
+ if (udph + 1 > data_end)
+ return 0;
+
+ dport = ntohs(udph->dest);
+ return dport;
+}
+
+static __always_inline
+int get_proto_ipv4(struct xdp_md *ctx, u64 nh_off)
+{
+ void *data_end = (void *)(long)ctx->data_end;
+ void *data = (void *)(long)ctx->data;
+ struct iphdr *iph = data + nh_off;
+
+ if (iph + 1 > data_end)
+ return 0;
+ return iph->protocol;
+}
+
+static __always_inline
+int get_proto_ipv6(struct xdp_md *ctx, u64 nh_off)
+{
+ void *data_end = (void *)(long)ctx->data_end;
+ void *data = (void *)(long)ctx->data;
+ struct ipv6hdr *ip6h = data + nh_off;
+
+ if (ip6h + 1 > data_end)
+ return 0;
+ return ip6h->nexthdr;
+}
+
+SEC("xdp_cpu_map0")
+int xdp_prognum0_no_touch(struct xdp_md *ctx)
+{
+ void *data_end = (void *)(long)ctx->data_end;
+ void *data = (void *)(long)ctx->data;
+ struct datarec *rec;
+ u32 *cpu_selected;
+ u32 cpu_dest;
+ u32 key = 0;
+
+ /* Only use first entry in cpus_available */
+ cpu_selected = bpf_map_lookup_elem(&cpus_available, &key);
+ if (!cpu_selected)
+ return XDP_ABORTED;
+ cpu_dest = *cpu_selected;
+
+ /* Count RX packet in map */
+ rec = bpf_map_lookup_elem(&rx_cnt, &key);
+ if (rec)
+ rec->processed++;
+
+ return bpf_redirect_map(&cpu_map, cpu_dest, 0);
+}
+
+SEC("xdp_cpu_map1_touch_data")
+int xdp_prognum1_touch_data(struct xdp_md *ctx)
+{
+ void *data_end = (void *)(long)ctx->data_end;
+ void *data = (void *)(long)ctx->data;
+ struct ethhdr *eth = data;
+ struct datarec *rec;
+ u32 *cpu_selected;
+ u32 cpu_dest;
+ u16 eth_type;
+ u32 key = 0;
+
+ /* Only use first entry in cpus_available */
+ cpu_selected = bpf_map_lookup_elem(&cpus_available, &key);
+ if (!cpu_selected)
+ return XDP_ABORTED;
+ cpu_dest = *cpu_selected;
+
+ /* Validate packet length is minimum Eth header size */
+ if (eth + 1 > data_end)
+ return XDP_ABORTED;
+
+ /* Count RX packet in map */
+ rec = bpf_map_lookup_elem(&rx_cnt, &key);
+ if (!rec)
+ return XDP_ABORTED;
+ rec->processed++;
+
+ /* Read packet data, and use it (drop non 802.3 Ethertypes) */
+ eth_type = eth->h_proto;
+ if (ntohs(eth_type) < ETH_P_802_3_MIN) {
+ rec->dropped++;
+ return XDP_DROP;
+ }
+
+ return bpf_redirect_map(&cpu_map, cpu_dest, 0);
+}
+
+SEC("xdp_cpu_map2_round_robin")
+int xdp_prognum2_round_robin(struct xdp_md *ctx)
+{
+ void *data_end = (void *)(long)ctx->data_end;
+ void *data = (void *)(long)ctx->data;
+ struct ethhdr *eth = data;
+ struct datarec *rec;
+ u32 cpu_dest;
+ u32 *cpu_lookup;
+ u32 key0 = 0;
+
+ u32 *cpu_selected;
+ u32 *cpu_iterator;
+ u32 *cpu_max;
+ u32 cpu_idx;
+
+ cpu_max = bpf_map_lookup_elem(&cpus_count, &key0);
+ if (!cpu_max)
+ return XDP_ABORTED;
+
+ cpu_iterator = bpf_map_lookup_elem(&cpus_iterator, &key0);
+ if (!cpu_iterator)
+ return XDP_ABORTED;
+ cpu_idx = *cpu_iterator;
+
+ *cpu_iterator += 1;
+ if (*cpu_iterator == *cpu_max)
+ *cpu_iterator = 0;
+
+ cpu_selected = bpf_map_lookup_elem(&cpus_available, &cpu_idx);
+ if (!cpu_selected)
+ return XDP_ABORTED;
+ cpu_dest = *cpu_selected;
+
+ /* Count RX packet in map */
+ rec = bpf_map_lookup_elem(&rx_cnt, &key0);
+ if (!rec)
+ return XDP_ABORTED;
+ rec->processed++;
+
+ /* Check cpu_dest is valid */
+ cpu_lookup = bpf_map_lookup_elem(&cpu_map, &cpu_dest);
+ if (!cpu_lookup) {
+ rec->issue++;
+ return XDP_DROP;
+ }
+
+ if (cpu_dest >= MAX_CPUS)
+ return XDP_ABORTED;
+
+ return bpf_redirect_map(&cpu_map, cpu_dest, 0);
+}
+
+SEC("xdp_cpu_map3_proto_separate")
+int xdp_prognum3_proto_separate(struct xdp_md *ctx)
+{
+ void *data_end = (void *)(long)ctx->data_end;
+ void *data = (void *)(long)ctx->data;
+ struct ethhdr *eth = data;
+ u8 ip_proto = IPPROTO_UDP;
+ struct datarec *rec;
+ u16 eth_proto = 0;
+ u64 l3_offset = 0;
+ u32 cpu_dest = 0;
+ u32 cpu_idx = 0;
+ u32 *cpu_lookup;
+ u32 key = 0;
+
+ /* Count RX packet in map */
+ rec = bpf_map_lookup_elem(&rx_cnt, &key);
+ if (!rec)
+ return XDP_ABORTED;
+ rec->processed++;
+
+ if (!(parse_eth(eth, data_end, ð_proto, &l3_offset)))
+ return XDP_PASS; /* Just skip */
+
+ /* Extract L4 protocol */
+ switch (eth_proto) {
+ case ETH_P_IP:
+ ip_proto = get_proto_ipv4(ctx, l3_offset);
+ break;
+ case ETH_P_IPV6:
+ ip_proto = get_proto_ipv6(ctx, l3_offset);
+ break;
+ case ETH_P_ARP:
+ cpu_idx = 0; /* ARP packet handled on separate CPU */
+ break;
+ default:
+ cpu_idx = 0;
+ }
+
+ /* Choose CPU based on L4 protocol */
+ switch (ip_proto) {
+ case IPPROTO_ICMP:
+ case IPPROTO_ICMPV6:
+ cpu_idx = 2;
+ break;
+ case IPPROTO_TCP:
+ cpu_idx = 0;
+ break;
+ case IPPROTO_UDP:
+ cpu_idx = 1;
+ break;
+ default:
+ cpu_idx = 0;
+ }
+
+ cpu_lookup = bpf_map_lookup_elem(&cpus_available, &cpu_idx);
+ if (!cpu_lookup)
+ return XDP_ABORTED;
+ cpu_dest = *cpu_lookup;
+
+ if (cpu_dest >= MAX_CPUS)
+ return XDP_ABORTED;
+
+ /* Check cpu_dest is valid */
+ cpu_lookup = bpf_map_lookup_elem(&cpu_map, &cpu_dest);
+ if (!cpu_lookup) {
+ rec->issue++;
+ return XDP_DROP;
+ }
+
+ return bpf_redirect_map(&cpu_map, cpu_dest, 0);
+}
+
+SEC("xdp_cpu_map4_ddos_filter_pktgen")
+int xdp_prognum4_ddos_filter_pktgen(struct xdp_md *ctx)
+{
+ void *data_end = (void *)(long)ctx->data_end;
+ void *data = (void *)(long)ctx->data;
+ struct ethhdr *eth = data;
+ u8 ip_proto = IPPROTO_UDP;
+ struct datarec *rec;
+ u16 eth_proto = 0;
+ u64 l3_offset = 0;
+ u32 cpu_dest = 0;
+ u32 cpu_idx = 0;
+ u16 dest_port;
+ u32 *cpu_lookup;
+ u32 key = 0;
+
+ /* Count RX packet in map */
+ rec = bpf_map_lookup_elem(&rx_cnt, &key);
+ if (!rec)
+ return XDP_ABORTED;
+ rec->processed++;
+
+ if (!(parse_eth(eth, data_end, ð_proto, &l3_offset)))
+ return XDP_PASS; /* Just skip */
+
+ /* Extract L4 protocol */
+ switch (eth_proto) {
+ case ETH_P_IP:
+ ip_proto = get_proto_ipv4(ctx, l3_offset);
+ break;
+ case ETH_P_IPV6:
+ ip_proto = get_proto_ipv6(ctx, l3_offset);
+ break;
+ case ETH_P_ARP:
+ cpu_idx = 0; /* ARP packet handled on separate CPU */
+ break;
+ default:
+ cpu_idx = 0;
+ }
+
+ /* Choose CPU based on L4 protocol */
+ switch (ip_proto) {
+ case IPPROTO_ICMP:
+ case IPPROTO_ICMPV6:
+ cpu_idx = 2;
+ break;
+ case IPPROTO_TCP:
+ cpu_idx = 0;
+ break;
+ case IPPROTO_UDP:
+ cpu_idx = 1;
+ /* DDoS filter UDP port 9 (pktgen) */
+ dest_port = get_dest_port_ipv4_udp(ctx, l3_offset);
+ if (dest_port == 9) {
+ if (rec)
+ rec->dropped++;
+ return XDP_DROP;
+ }
+ break;
+ default:
+ cpu_idx = 0;
+ }
+
+ cpu_lookup = bpf_map_lookup_elem(&cpus_available, &cpu_idx);
+ if (!cpu_lookup)
+ return XDP_ABORTED;
+ cpu_dest = *cpu_lookup;
+
+ if (cpu_dest >= MAX_CPUS)
+ return XDP_ABORTED;
+
+ /* Check cpu_dest is valid */
+ cpu_lookup = bpf_map_lookup_elem(&cpu_map, &cpu_dest);
+ if (!cpu_lookup) {
+ rec->issue++;
+ return XDP_DROP;
+ }
+
+ if (cpu_dest >= MAX_CPUS)
+ return XDP_ABORTED;
+
+ return bpf_redirect_map(&cpu_map, cpu_dest, 0);
+}
+
+
+char _license[] SEC("license") = "GPL";
+
+/*** Trace point code ***/
+
+/* Tracepoint format: /sys/kernel/debug/tracing/events/xdp/xdp_redirect/format
+ * Code in: kernel/include/trace/events/xdp.h
+ */
+struct xdp_redirect_ctx {
+ u64 __pad; // First 8 bytes are not accessible by bpf code
+ int prog_id; // offset:8; size:4; signed:1;
+ u32 act; // offset:12 size:4; signed:0;
+ int ifindex; // offset:16 size:4; signed:1;
+ int err; // offset:20 size:4; signed:1;
+ int to_ifindex; // offset:24 size:4; signed:1;
+ u32 map_id; // offset:28 size:4; signed:0;
+ int map_index; // offset:32 size:4; signed:1;
+}; // offset:36
+
+enum {
+ XDP_REDIRECT_SUCCESS = 0,
+ XDP_REDIRECT_ERROR = 1
+};
+
+static __always_inline
+int xdp_redirect_collect_stat(struct xdp_redirect_ctx *ctx)
+{
+ u32 key = XDP_REDIRECT_ERROR;
+ struct datarec *rec;
+ int err = ctx->err;
+
+ if (!err)
+ key = XDP_REDIRECT_SUCCESS;
+
+ rec = bpf_map_lookup_elem(&redirect_err_cnt, &key);
+ if (!rec)
+ return 0;
+ rec->dropped += 1;
+
+ return 0; /* Indicate event was filtered (no further processing)*/
+ /*
+ * Returning 1 here would allow e.g. a perf-record tracepoint
+ * to see and record these events, but it doesn't work well
+ * in-practice as stopping perf-record also unload this
+ * bpf_prog. Plus, there is additional overhead of doing so.
+ */
+}
+
+SEC("tracepoint/xdp/xdp_redirect_err")
+int trace_xdp_redirect_err(struct xdp_redirect_ctx *ctx)
+{
+ return xdp_redirect_collect_stat(ctx);
+}
+
+SEC("tracepoint/xdp/xdp_redirect_map_err")
+int trace_xdp_redirect_map_err(struct xdp_redirect_ctx *ctx)
+{
+ return xdp_redirect_collect_stat(ctx);
+}
+
+/* Tracepoint format: /sys/kernel/debug/tracing/events/xdp/xdp_exception/format
+ * Code in: kernel/include/trace/events/xdp.h
+ */
+struct xdp_exception_ctx {
+ u64 __pad; // First 8 bytes are not accessible by bpf code
+ int prog_id; // offset:8; size:4; signed:1;
+ u32 act; // offset:12; size:4; signed:0;
+ int ifindex; // offset:16; size:4; signed:1;
+};
+
+SEC("tracepoint/xdp/xdp_exception")
+int trace_xdp_exception(struct xdp_exception_ctx *ctx)
+{
+ struct datarec *rec;
+ u32 key = 0;
+
+ rec = bpf_map_lookup_elem(&exception_cnt, &key);
+ if (!rec)
+ return 1;
+ rec->dropped += 1;
+
+ return 0;
+}
+
+/* Tracepoint: /sys/kernel/debug/tracing/events/xdp/xdp_cpumap_enqueue/format
+ * Code in: kernel/include/trace/events/xdp.h
+ */
+struct cpumap_enqueue_ctx {
+ u64 __pad; // First 8 bytes are not accessible by bpf code
+ int map_id; // offset:8; size:4; signed:1;
+ u32 act; // offset:12; size:4; signed:0;
+ int cpu; // offset:16; size:4; signed:1;
+ unsigned int drops; // offset:20; size:4; signed:0;
+ unsigned int processed; // offset:24; size:4; signed:0;
+ int to_cpu; // offset:28; size:4; signed:1;
+};
+
+SEC("tracepoint/xdp/xdp_cpumap_enqueue")
+int trace_xdp_cpumap_enqueue(struct cpumap_enqueue_ctx *ctx)
+{
+ u32 to_cpu = ctx->to_cpu;
+ struct datarec *rec;
+
+ if (to_cpu >= MAX_CPUS)
+ return 1;
+
+ rec = bpf_map_lookup_elem(&cpumap_enqueue_cnt, &to_cpu);
+ if (!rec)
+ return 0;
+ rec->processed += ctx->processed;
+ rec->dropped += ctx->drops;
+
+ /* Detect misconfig. Redirect to "same" CPU, makes no sense
+ * and indicate user of cpumap have not done proper IRQ RXq
+ * setup.
+ */
+ if (ctx->cpu == ctx->to_cpu)
+ rec->issue += ctx->processed;
+
+ /* Inception: It's possible to detect overload situations, via
+ * this tracepoint. This can be used for creating a feedback
+ * loop to XDP, which can take appropiate actions to mitigate
+ * this overload situation.
+ */
+ return 0;
+}
+
+/* Tracepoint: /sys/kernel/debug/tracing/events/xdp/xdp_cpumap_kthread/format
+ * Code in: kernel/include/trace/events/xdp.h
+ */
+struct cpumap_kthread_ctx {
+ u64 __pad; // First 8 bytes are not accessible by bpf code
+ int map_id; // offset:8; size:4; signed:1;
+ u32 act; // offset:12; size:4; signed:0;
+ int cpu; // offset:16; size:4; signed:1;
+ unsigned int drops; // offset:20; size:4; signed:0;
+ unsigned int processed; // offset:24; size:4; signed:0;
+ int time_limit; // offset:28; size:4; signed:1;
+};
+
+SEC("tracepoint/xdp/xdp_cpumap_kthread")
+int trace_xdp_cpumap_kthread(struct cpumap_kthread_ctx *ctx)
+{
+ struct datarec *rec;
+ u32 key = 0;
+
+ rec = bpf_map_lookup_elem(&cpumap_kthread_cnt, &key);
+ if (!rec)
+ return 0;
+ rec->processed += ctx->processed;
+ rec->dropped += ctx->drops;
+
+ /* Detect when time limit was exceeded, but queue was not-empty */
+ if (ctx->processed > 0 && ctx->time_limit)
+ rec->issue++;
+
+ return 0;
+}
diff --git a/samples/bpf/xdp_redirect_cpu_user.c b/samples/bpf/xdp_redirect_cpu_user.c
new file mode 100644
index 000000000000..15a25c23b195
--- /dev/null
+++ b/samples/bpf/xdp_redirect_cpu_user.c
@@ -0,0 +1,647 @@
+/* GPLv2 Copyright(c) 2017 Jesper Dangaard Brouer, Red Hat, Inc.
+ */
+static const char *__doc__ =
+ " XDP redirect with a CPU-map type \"BPF_MAP_TYPE_CPUMAP\"";
+
+#include <errno.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <string.h>
+#include <unistd.h>
+#include <locale.h>
+#include <sys/resource.h>
+#include <getopt.h>
+#include <net/if.h>
+#include <time.h>
+
+#include <arpa/inet.h>
+#include <linux/if_link.h>
+
+#define MAX_CPUS 12 /* WARNING - sync with _kern.c */
+
+/* How many xdp_progs are defined in _kern.c */
+#define MAX_PROG 5
+
+/* Wanted to get rid of bpf_load.h and fake-"libbpf.h" (and instead
+ * use bpf/libbpf.h), but cannot as (currently) needed for XDP
+ * attaching to a device via set_link_xdp_fd()
+ */
+#include "libbpf.h"
+#include "bpf_load.h"
+
+#include "bpf_util.h"
+
+static int ifindex = -1;
+static char ifname_buf[IF_NAMESIZE];
+static char *ifname;
+
+static __u32 xdp_flags;
+
+/* Exit return codes */
+#define EXIT_OK 0
+#define EXIT_FAIL 1
+#define EXIT_FAIL_OPTION 2
+#define EXIT_FAIL_XDP 3
+#define EXIT_FAIL_BPF 4
+#define EXIT_FAIL_MEM 5
+
+static const struct option long_options[] = {
+ {"help", no_argument, NULL, 'h' },
+ {"dev", required_argument, NULL, 'd' },
+ {"skb-mode", no_argument, NULL, 'S' },
+ {"debug", no_argument, NULL, 'D' },
+ {"sec", required_argument, NULL, 's' },
+ {"prognum", required_argument, NULL, 'p' },
+ {"qsize", required_argument, NULL, 'q' },
+ {"cpu", required_argument, NULL, 'c' },
+ {"no-separators", no_argument, NULL, 'z' },
+ {0, 0, NULL, 0 }
+};
+
+static void int_exit(int sig)
+{
+ fprintf(stderr,
+ "Interrupted: Removing XDP program on ifindex:%d device:%s\n",
+ ifindex, ifname);
+ if (ifindex > -1)
+ set_link_xdp_fd(ifindex, -1, xdp_flags);
+ exit(EXIT_OK);
+}
+
+static void usage(char *argv[])
+{
+ int i;
+
+ printf("\nDOCUMENTATION:\n%s\n", __doc__);
+ printf("\n");
+ printf(" Usage: %s (options-see-below)\n", argv[0]);
+ printf(" Listing options:\n");
+ for (i = 0; long_options[i].name != 0; i++) {
+ printf(" --%-12s", long_options[i].name);
+ if (long_options[i].flag != NULL)
+ printf(" flag (internal value:%d)",
+ *long_options[i].flag);
+ else
+ printf(" short-option: -%c",
+ long_options[i].val);
+ printf("\n");
+ }
+ printf("\n");
+}
+
+/* gettime returns the current time of day in nanoseconds.
+ * Cost: clock_gettime (ns) => 26ns (CLOCK_MONOTONIC)
+ * clock_gettime (ns) => 9ns (CLOCK_MONOTONIC_COARSE)
+ */
+#define NANOSEC_PER_SEC 1000000000 /* 10^9 */
+static __u64 gettime(void)
+{
+ struct timespec t;
+ int res;
+
+ res = clock_gettime(CLOCK_MONOTONIC, &t);
+ if (res < 0) {
+ fprintf(stderr, "Error with gettimeofday! (%i)\n", res);
+ exit(EXIT_FAIL);
+ }
+ return (__u64) t.tv_sec * NANOSEC_PER_SEC + t.tv_nsec;
+}
+
+/* Common stats data record shared with _kern.c */
+struct datarec {
+ __u64 processed;
+ __u64 dropped;
+ __u64 issue;
+};
+struct record {
+ __u64 timestamp;
+ struct datarec total;
+ struct datarec *cpu;
+};
+struct stats_record {
+ struct record rx_cnt;
+ struct record redir_err;
+ struct record kthread;
+ struct record exception;
+ struct record enq[MAX_CPUS];
+};
+
+static bool map_collect_percpu(int fd, __u32 key, struct record *rec)
+{
+ /* For percpu maps, userspace gets a value per possible CPU */
+ unsigned int nr_cpus = bpf_num_possible_cpus();
+ struct datarec values[nr_cpus];
+ __u64 sum_processed = 0;
+ __u64 sum_dropped = 0;
+ __u64 sum_issue = 0;
+ int i;
+
+ if ((bpf_map_lookup_elem(fd, &key, values)) != 0) {
+ fprintf(stderr,
+ "ERR: bpf_map_lookup_elem failed key:0x%X\n", key);
+ return false;
+ }
+ /* Get time as close as possible to reading map contents */
+ rec->timestamp = gettime();
+
+ /* Record and sum values from each CPU */
+ for (i = 0; i < nr_cpus; i++) {
+ rec->cpu[i].processed = values[i].processed;
+ sum_processed += values[i].processed;
+ rec->cpu[i].dropped = values[i].dropped;
+ sum_dropped += values[i].dropped;
+ rec->cpu[i].issue = values[i].issue;
+ sum_issue += values[i].issue;
+ }
+ rec->total.processed = sum_processed;
+ rec->total.dropped = sum_dropped;
+ rec->total.issue = sum_issue;
+ return true;
+}
+
+static struct datarec *alloc_record_per_cpu(void)
+{
+ unsigned int nr_cpus = bpf_num_possible_cpus();
+ struct datarec *array;
+ size_t size;
+
+ size = sizeof(struct datarec) * nr_cpus;
+ array = malloc(size);
+ memset(array, 0, size);
+ if (!array) {
+ fprintf(stderr, "Mem alloc error (nr_cpus:%u)\n", nr_cpus);
+ exit(EXIT_FAIL_MEM);
+ }
+ return array;
+}
+
+static struct stats_record *alloc_stats_record(void)
+{
+ struct stats_record *rec;
+ int i;
+
+ rec = malloc(sizeof(*rec));
+ memset(rec, 0, sizeof(*rec));
+ if (!rec) {
+ fprintf(stderr, "Mem alloc error\n");
+ exit(EXIT_FAIL_MEM);
+ }
+ rec->rx_cnt.cpu = alloc_record_per_cpu();
+ rec->redir_err.cpu = alloc_record_per_cpu();
+ rec->kthread.cpu = alloc_record_per_cpu();
+ rec->exception.cpu = alloc_record_per_cpu();
+ for (i = 0; i < MAX_CPUS; i++)
+ rec->enq[i].cpu = alloc_record_per_cpu();
+
+ return rec;
+}
+
+static void free_stats_record(struct stats_record *r)
+{
+ int i;
+
+ for (i = 0; i < MAX_CPUS; i++)
+ free(r->enq[i].cpu);
+ free(r->exception.cpu);
+ free(r->kthread.cpu);
+ free(r->redir_err.cpu);
+ free(r->rx_cnt.cpu);
+ free(r);
+}
+
+static double calc_period(struct record *r, struct record *p)
+{
+ double period_ = 0;
+ __u64 period = 0;
+
+ period = r->timestamp - p->timestamp;
+ if (period > 0)
+ period_ = ((double) period / NANOSEC_PER_SEC);
+
+ return period_;
+}
+
+static __u64 calc_pps(struct datarec *r, struct datarec *p, double period_)
+{
+ __u64 packets = 0;
+ __u64 pps = 0;
+
+ if (period_ > 0) {
+ packets = r->processed - p->processed;
+ pps = packets / period_;
+ }
+ return pps;
+}
+
+static __u64 calc_drop_pps(struct datarec *r, struct datarec *p, double period_)
+{
+ __u64 packets = 0;
+ __u64 pps = 0;
+
+ if (period_ > 0) {
+ packets = r->dropped - p->dropped;
+ pps = packets / period_;
+ }
+ return pps;
+}
+
+static __u64 calc_errs_pps(struct datarec *r,
+ struct datarec *p, double period_)
+{
+ __u64 packets = 0;
+ __u64 pps = 0;
+
+ if (period_ > 0) {
+ packets = r->issue - p->issue;
+ pps = packets / period_;
+ }
+ return pps;
+}
+
+static void stats_print(struct stats_record *stats_rec,
+ struct stats_record *stats_prev,
+ int prog_num)
+{
+ unsigned int nr_cpus = bpf_num_possible_cpus();
+ double pps = 0, drop = 0, err = 0;
+ struct record *rec, *prev;
+ int to_cpu;
+ double t;
+ int i;
+
+ /* Header */
+ printf("Running XDP/eBPF prog_num:%d\n", prog_num);
+ printf("%-15s %-7s %-14s %-11s %-9s\n",
+ "XDP-cpumap", "CPU:to", "pps", "drop-pps", "extra-info");
+
+ /* XDP rx_cnt */
+ {
+ char *fmt_rx = "%-15s %-7d %'-14.0f %'-11.0f %'-10.0f %s\n";
+ char *fm2_rx = "%-15s %-7s %'-14.0f %'-11.0f\n";
+ char *errstr = "";
+
+ rec = &stats_rec->rx_cnt;
+ prev = &stats_prev->rx_cnt;
+ t = calc_period(rec, prev);
+ for (i = 0; i < nr_cpus; i++) {
+ struct datarec *r = &rec->cpu[i];
+ struct datarec *p = &prev->cpu[i];
+
+ pps = calc_pps(r, p, t);
+ drop = calc_drop_pps(r, p, t);
+ err = calc_errs_pps(r, p, t);
+ if (err > 0)
+ errstr = "cpu-dest/err";
+ if (pps > 0)
+ printf(fmt_rx, "XDP-RX",
+ i, pps, drop, err, errstr);
+ }
+ pps = calc_pps(&rec->total, &prev->total, t);
+ drop = calc_drop_pps(&rec->total, &prev->total, t);
+ err = calc_errs_pps(&rec->total, &prev->total, t);
+ printf(fm2_rx, "XDP-RX", "total", pps, drop);
+ }
+
+ /* cpumap enqueue stats */
+ for (to_cpu = 0; to_cpu < MAX_CPUS; to_cpu++) {
+ char *fmt = "%-15s %3d:%-3d %'-14.0f %'-11.0f %'-10.0f %s\n";
+ char *fm2 = "%-15s %3s:%-3d %'-14.0f %'-11.0f %'-10.0f %s\n";
+ char *errstr = "";
+
+ rec = &stats_rec->enq[to_cpu];
+ prev = &stats_prev->enq[to_cpu];
+ t = calc_period(rec, prev);
+ for (i = 0; i < nr_cpus; i++) {
+ struct datarec *r = &rec->cpu[i];
+ struct datarec *p = &prev->cpu[i];
+
+ pps = calc_pps(r, p, t);
+ drop = calc_drop_pps(r, p, t);
+ err = calc_errs_pps(r, p, t);
+ if (err > 0)
+ errstr = "same-cpu/pps";
+ if (pps > 0)
+ printf(fmt, "cpumap-enqueue",
+ i, to_cpu, pps, drop, err, errstr);
+ }
+ pps = calc_pps(&rec->total, &prev->total, t);
+ if (pps > 0) {
+ drop = calc_drop_pps(&rec->total, &prev->total, t);
+ err = calc_errs_pps(&rec->total, &prev->total, t);
+ printf(fm2, "cpumap-enqueue",
+ "sum", to_cpu, pps, drop, err, errstr);
+ }
+ }
+
+ /* cpumap kthread stats */
+ {
+ char *fmt_k = "%-15s %-7d %'-14.0f %'-11.0f %-10.0f %s\n";
+ char *fm2_k = "%-15s %-7s %'-14.0f %'-11.0f %-10.0f %s\n";
+ char *errstr = "";
+
+ rec = &stats_rec->kthread;
+ prev = &stats_prev->kthread;
+ t = calc_period(rec, prev);
+ for (i = 0; i < nr_cpus; i++) {
+ struct datarec *r = &rec->cpu[i];
+ struct datarec *p = &prev->cpu[i];
+
+ pps = calc_pps(r, p, t);
+ drop = calc_drop_pps(r, p, t);
+ err = calc_errs_pps(r, p, t);
+ if (err > 0)
+ errstr = "time_exceed";
+ if (pps > 0)
+ printf(fmt_k, "cpumap_kthread",
+ i, pps, drop, err, errstr);
+ }
+ pps = calc_pps(&rec->total, &prev->total, t);
+ drop = calc_drop_pps(&rec->total, &prev->total, t);
+ printf(fm2_k, "cpumap_kthread", "total", pps, drop);
+ }
+
+ /* XDP redirect err tracepoints (very unlikely) */
+ {
+ char *fmt_err = "%-15s %-7d %'-14.0f %'-11.0f\n";
+ char *fm2_err = "%-15s %-7s %'-14.0f %'-11.0f\n";
+
+ rec = &stats_rec->redir_err;
+ prev = &stats_prev->redir_err;
+ t = calc_period(rec, prev);
+ for (i = 0; i < nr_cpus; i++) {
+ struct datarec *r = &rec->cpu[i];
+ struct datarec *p = &prev->cpu[i];
+
+ pps = calc_pps(r, p, t);
+ drop = calc_drop_pps(r, p, t);
+ if (pps > 0)
+ printf(fmt_err, "redirect_err", i, pps, drop);
+ }
+ pps = calc_pps(&rec->total, &prev->total, t);
+ drop = calc_drop_pps(&rec->total, &prev->total, t);
+ printf(fm2_err, "redirect_err", "total", pps, drop);
+ }
+
+ /* XDP general exception tracepoints */
+ {
+ char *fmt_err = "%-15s %-7d %'-14.0f %'-11.0f\n";
+ char *fm2_err = "%-15s %-7s %'-14.0f %'-11.0f\n";
+
+ rec = &stats_rec->exception;
+ prev = &stats_prev->exception;
+ t = calc_period(rec, prev);
+ for (i = 0; i < nr_cpus; i++) {
+ struct datarec *r = &rec->cpu[i];
+ struct datarec *p = &prev->cpu[i];
+
+ pps = calc_pps(r, p, t);
+ drop = calc_drop_pps(r, p, t);
+ if (pps > 0)
+ printf(fmt_err, "xdp_exception", i, pps, drop);
+ }
+ pps = calc_pps(&rec->total, &prev->total, t);
+ drop = calc_drop_pps(&rec->total, &prev->total, t);
+ printf(fm2_err, "xdp_exception", "total", pps, drop);
+ }
+
+ printf("\n");
+ fflush(stdout);
+}
+
+static void stats_collect(struct stats_record *rec)
+{
+ int fd, i;
+
+ fd = map_fd[1]; /* map: rx_cnt */
+ map_collect_percpu(fd, 0, &rec->rx_cnt);
+
+ fd = map_fd[2]; /* map: redirect_err_cnt */
+ map_collect_percpu(fd, 1, &rec->redir_err);
+
+ fd = map_fd[3]; /* map: cpumap_enqueue_cnt */
+ for (i = 0; i < MAX_CPUS; i++)
+ map_collect_percpu(fd, i, &rec->enq[i]);
+
+ fd = map_fd[4]; /* map: cpumap_kthread_cnt */
+ map_collect_percpu(fd, 0, &rec->kthread);
+
+ fd = map_fd[8]; /* map: exception_cnt */
+ map_collect_percpu(fd, 0, &rec->exception);
+}
+
+
+/* Pointer swap trick */
+static inline void swap(struct stats_record **a, struct stats_record **b)
+{
+ struct stats_record *tmp;
+
+ tmp = *a;
+ *a = *b;
+ *b = tmp;
+}
+
+static void stats_poll(int interval, bool use_separators, int prog_num)
+{
+ struct stats_record *record, *prev;
+
+ record = alloc_stats_record();
+ prev = alloc_stats_record();
+ stats_collect(record);
+
+ /* Trick to pretty printf with thousands separators use %' */
+ if (use_separators)
+ setlocale(LC_NUMERIC, "en_US");
+
+ while (1) {
+ swap(&prev, &record);
+ stats_collect(record);
+ stats_print(record, prev, prog_num);
+ sleep(interval);
+ }
+
+ free_stats_record(record);
+ free_stats_record(prev);
+}
+
+static int create_cpu_entry(__u32 cpu, __u32 queue_size,
+ __u32 avail_idx, bool new)
+{
+ __u32 curr_cpus_count;
+ __u32 key = 0;
+ int ret;
+
+ /* Add a CPU entry to cpumap, as this allocate a cpu entry in
+ * the kernel for the cpu.
+ */
+ ret = bpf_map_update_elem(map_fd[0], &cpu, &queue_size, 0);
+ if (ret) {
+ fprintf(stderr, "Create CPU entry failed\n");
+ exit(EXIT_FAIL_BPF);
+ }
+
+ /* Inform bpf_prog's that a new CPU is available to select
+ * from via some control maps.
+ */
+ /* map_fd[5] = cpus_available */
+ ret = bpf_map_update_elem(map_fd[5], &avail_idx, &cpu, 0);
+ if (ret) {
+ fprintf(stderr, "Add to avail CPUs failed\n");
+ exit(EXIT_FAIL_BPF);
+ }
+
+ /* When not replacing/updating existing entry, bump the count */
+ /* map_fd[6] = cpus_count */
+ if (new) {
+ ret = bpf_map_lookup_elem(map_fd[6], &key, &curr_cpus_count);
+ if (ret) {
+ fprintf(stderr, "Failed reading curr cpus_count\n");
+ exit(EXIT_FAIL_BPF);
+ }
+ curr_cpus_count++;
+ ret = bpf_map_update_elem(map_fd[6], &key, &curr_cpus_count, 0);
+ if (ret) {
+ fprintf(stderr, "Failed write curr cpus_count\n");
+ exit(EXIT_FAIL_BPF);
+ }
+ }
+ /* map_fd[7] = cpus_iterator */
+ printf("%s CPU:%u as idx:%u cpus_count:%u\n",
+ new ? "Add-new":"Replace", cpu, avail_idx, curr_cpus_count);
+
+ return 0;
+}
+
+int main(int argc, char **argv)
+{
+ struct rlimit r = {10 * 1024*1024, RLIM_INFINITY};
+ bool use_separators = true;
+ char filename[256];
+ bool debug = false;
+ int added_cpus = 0;
+ int longindex = 0;
+ int interval = 2;
+ int prog_num = 0;
+ int add_cpu = -1;
+ __u32 qsize;
+ int opt;
+
+ /* Notice: choosing he queue size is very important with the
+ * ixgbe driver, because it's driver page recycling trick is
+ * dependend on pages being returned quickly. The number of
+ * out-standing packets in the system must be less-than 2x
+ * RX-ring size.
+ */
+ qsize = 128+64;
+
+ snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
+
+ if (setrlimit(RLIMIT_MEMLOCK, &r)) {
+ perror("setrlimit(RLIMIT_MEMLOCK)");
+ return 1;
+ }
+
+ if (load_bpf_file(filename)) {
+ fprintf(stderr, "ERR in load_bpf_file(): %s", bpf_log_buf);
+ return EXIT_FAIL;
+ }
+
+ if (!prog_fd[0]) {
+ fprintf(stderr, "ERR: load_bpf_file: %s\n", strerror(errno));
+ return EXIT_FAIL;
+ }
+
+ /* Parse commands line args */
+ while ((opt = getopt_long(argc, argv, "hSd:",
+ long_options, &longindex)) != -1) {
+ switch (opt) {
+ case 'd':
+ if (strlen(optarg) >= IF_NAMESIZE) {
+ fprintf(stderr, "ERR: --dev name too long\n");
+ goto error;
+ }
+ ifname = (char *)&ifname_buf;
+ strncpy(ifname, optarg, IF_NAMESIZE);
+ ifindex = if_nametoindex(ifname);
+ if (ifindex == 0) {
+ fprintf(stderr,
+ "ERR: --dev name unknown err(%d):%s\n",
+ errno, strerror(errno));
+ goto error;
+ }
+ break;
+ case 's':
+ interval = atoi(optarg);
+ break;
+ case 'S':
+ xdp_flags |= XDP_FLAGS_SKB_MODE;
+ break;
+ case 'D':
+ debug = true;
+ break;
+ case 'z':
+ use_separators = false;
+ break;
+ case 'p':
+ /* Selecting eBPF prog to load */
+ prog_num = atoi(optarg);
+ if (prog_num < 0 || prog_num >= MAX_PROG) {
+ fprintf(stderr,
+ "--prognum too large err(%d):%s\n",
+ errno, strerror(errno));
+ goto error;
+ }
+ break;
+ case 'c':
+ /* Add multiple CPUs */
+ add_cpu = strtoul(optarg, NULL, 0);
+ if (add_cpu > MAX_CPUS) {
+ fprintf(stderr,
+ "--cpu nr too large for cpumap err(%d):%s\n",
+ errno, strerror(errno));
+ goto error;
+ }
+ create_cpu_entry(add_cpu, qsize, added_cpus, true);
+ added_cpus++;
+ break;
+ case 'q':
+ qsize = atoi(optarg);
+ break;
+ case 'h':
+ error:
+ default:
+ usage(argv);
+ return EXIT_FAIL_OPTION;
+ }
+ }
+ /* Required option */
+ if (ifindex == -1) {
+ fprintf(stderr, "ERR: required option --dev missing\n");
+ usage(argv);
+ return EXIT_FAIL_OPTION;
+ }
+ /* Required option */
+ if (add_cpu == -1) {
+ fprintf(stderr, "ERR: required option --cpu missing\n");
+ fprintf(stderr, " Specify multiple --cpu option to add more\n");
+ usage(argv);
+ return EXIT_FAIL_OPTION;
+ }
+
+ /* Remove XDP program when program is interrupted */
+ signal(SIGINT, int_exit);
+
+ if (set_link_xdp_fd(ifindex, prog_fd[prog_num], xdp_flags) < 0) {
+ fprintf(stderr, "link set xdp fd failed\n");
+ return EXIT_FAIL_XDP;
+ }
+
+ if (debug) {
+ printf("Debug-mode reading trace pipe (fix #define DEBUG)\n");
+ read_trace_pipe();
+ }
+
+ stats_poll(interval, use_separators, prog_num);
+ return EXIT_OK;
+}
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