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linux-stable/samples/bpf/xdp_redirect_cpu_kern.c
Daniel T. Lee 451d1dc886 samples: bpf: update map definition to new syntax BTF-defined map 
Since, the new syntax of BTF-defined map has been introduced,
the syntax for using maps under samples directory are mixed up.
For example, some are already using the new syntax, and some are using
existing syntax by calling them as 'legacy'.

As stated at commit abd29c9314 ("libbpf: allow specifying map
definitions using BTF"), the BTF-defined map has more compatablility
with extending supported map definition features.

The commit doesn't replace all of the map to new BTF-defined map,
because some of the samples still use bpf_load instead of libbpf, which
can't properly create BTF-defined map.

This will only updates the samples which uses libbpf API for loading bpf
program. (ex. bpf_prog_load_xattr)

Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-11-08 19:21:52 -08:00

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/* 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"
#include "hash_func01.h"
#define MAX_CPUS 64 /* WARNING - sync with _user.c */
/* Special map type that can XDP_REDIRECT frames to another CPU */
struct {
__uint(type, BPF_MAP_TYPE_CPUMAP);
__uint(key_size, sizeof(u32));
__uint(value_size, sizeof(u32));
__uint(max_entries, MAX_CPUS);
} cpu_map SEC(".maps");
/* 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 {
__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
__type(key, u32);
__type(value, struct datarec);
__uint(max_entries, 1);
} rx_cnt SEC(".maps");
/* Used by trace point */
struct {
__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
__type(key, u32);
__type(value, struct datarec);
__uint(max_entries, 2);
/* TODO: have entries for all possible errno's */
} redirect_err_cnt SEC(".maps");
/* Used by trace point */
struct {
__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
__type(key, u32);
__type(value, struct datarec);
__uint(max_entries, MAX_CPUS);
} cpumap_enqueue_cnt SEC(".maps");
/* Used by trace point */
struct {
__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
__type(key, u32);
__type(value, struct datarec);
__uint(max_entries, 1);
} cpumap_kthread_cnt SEC(".maps");
/* Set of maps controlling available CPU, and for iterating through
* selectable redirect CPUs.
*/
struct {
__uint(type, BPF_MAP_TYPE_ARRAY);
__type(key, u32);
__type(value, u32);
__uint(max_entries, MAX_CPUS);
} cpus_available SEC(".maps");
struct {
__uint(type, BPF_MAP_TYPE_ARRAY);
__type(key, u32);
__type(value, u32);
__uint(max_entries, 1);
} cpus_count SEC(".maps");
struct {
__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
__type(key, u32);
__type(value, u32);
__uint(max_entries, 1);
} cpus_iterator SEC(".maps");
/* Used by trace point */
struct {
__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
__type(key, u32);
__type(value, struct datarec);
__uint(max_entries, 1);
} exception_cnt SEC(".maps");
/* 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;
}
/* Handle double 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;
}
*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)
return XDP_ABORTED;
rec->processed++;
if (cpu_dest >= MAX_CPUS) {
rec->issue++;
return XDP_ABORTED;
}
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;
}
if (cpu_dest >= MAX_CPUS) {
rec->issue++;
return XDP_ABORTED;
}
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++;
if (cpu_dest >= MAX_CPUS) {
rec->issue++;
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, &eth_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) {
rec->issue++;
return XDP_ABORTED;
}
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, &eth_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) {
rec->issue++;
return XDP_ABORTED;
}
return bpf_redirect_map(&cpu_map, cpu_dest, 0);
}
/* Hashing initval */
#define INITVAL 15485863
static __always_inline
u32 get_ipv4_hash_ip_pair(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;
u32 cpu_hash;
if (iph + 1 > data_end)
return 0;
cpu_hash = iph->saddr + iph->daddr;
cpu_hash = SuperFastHash((char *)&cpu_hash, 4, INITVAL + iph->protocol);
return cpu_hash;
}
static __always_inline
u32 get_ipv6_hash_ip_pair(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;
u32 cpu_hash;
if (ip6h + 1 > data_end)
return 0;
cpu_hash = ip6h->saddr.s6_addr32[0] + ip6h->daddr.s6_addr32[0];
cpu_hash += ip6h->saddr.s6_addr32[1] + ip6h->daddr.s6_addr32[1];
cpu_hash += ip6h->saddr.s6_addr32[2] + ip6h->daddr.s6_addr32[2];
cpu_hash += ip6h->saddr.s6_addr32[3] + ip6h->daddr.s6_addr32[3];
cpu_hash = SuperFastHash((char *)&cpu_hash, 4, INITVAL + ip6h->nexthdr);
return cpu_hash;
}
/* Load-Balance traffic based on hashing IP-addrs + L4-proto. The
* hashing scheme is symmetric, meaning swapping IP src/dest still hit
* same CPU.
*/
SEC("xdp_cpu_map5_lb_hash_ip_pairs")
int xdp_prognum5_lb_hash_ip_pairs(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 *cpu_max;
u32 cpu_hash;
u32 key = 0;
/* Count RX packet in map */
rec = bpf_map_lookup_elem(&rx_cnt, &key);
if (!rec)
return XDP_ABORTED;
rec->processed++;
cpu_max = bpf_map_lookup_elem(&cpus_count, &key);
if (!cpu_max)
return XDP_ABORTED;
if (!(parse_eth(eth, data_end, &eth_proto, &l3_offset)))
return XDP_PASS; /* Just skip */
/* Hash for IPv4 and IPv6 */
switch (eth_proto) {
case ETH_P_IP:
cpu_hash = get_ipv4_hash_ip_pair(ctx, l3_offset);
break;
case ETH_P_IPV6:
cpu_hash = get_ipv6_hash_ip_pair(ctx, l3_offset);
break;
case ETH_P_ARP: /* ARP packet handled on CPU idx 0 */
default:
cpu_hash = 0;
}
/* Choose CPU based on hash */
cpu_idx = cpu_hash % *cpu_max;
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) {
rec->issue++;
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;
/* Record bulk events, then userspace can calc average bulk size */
if (ctx->processed > 0)
rec->issue += 1;
/* 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 appropriate 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 sched; // 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;
/* Count times kthread yielded CPU via schedule call */
if (ctx->sched)
rec->issue++;
return 0;
}
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