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xdp_redirect_cpumap.bpf.c
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xdp_redirect_cpumap.bpf.c
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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 <bpf/vmlinux.h>
#include <xdp/xdp_sample_shared.h>
#include <xdp/xdp_sample.bpf.h>
#include <xdp/xdp_sample_common.bpf.h>
#include <xdp/parsing_helpers.h>
#include "hash_func01.h"
/* 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(struct bpf_cpumap_val));
} cpu_map 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);
} 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");
struct {
__uint(type, BPF_MAP_TYPE_DEVMAP);
__uint(key_size, sizeof(int));
__uint(value_size, sizeof(struct bpf_devmap_val));
__uint(max_entries, 1);
} tx_port SEC(".maps");
char tx_mac_addr[ETH_ALEN];
/* Helper parse functions */
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 (__builtin_expect(bpf_ntohs(eth_type) < ETH_P_802_3_MIN, 0))
return false;
/* Handle VLAN tagged packet */
if (eth_type == bpf_htons(ETH_P_8021Q) ||
eth_type == bpf_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 == bpf_htons(ETH_P_8021Q) ||
eth_type == bpf_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 = bpf_ntohs(eth_type);
*l3_offset = offset;
return true;
}
static __always_inline
__u16 get_port_ipv4_udp(struct xdp_md *ctx, __u64 nh_off, bool src)
{
void *data_end = (void *)(long)ctx->data_end;
void *data = (void *)(long)ctx->data;
struct iphdr *iph = data + nh_off;
struct udphdr *udph;
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;
if (src)
return bpf_ntohs(udph->source);
else
return bpf_ntohs(udph->dest);
}
static __always_inline
__u16 get_port_ipv6_udp(struct xdp_md *ctx, __u64 nh_off, bool src)
{
void *data_end = (void *)(long)ctx->data_end;
void *data = (void *)(long)ctx->data;
struct ipv6hdr *ip6h = data + nh_off;
struct udphdr *udph;
if (ip6h + 1 > data_end)
return 0;
if (!(ip6h->nexthdr == IPPROTO_UDP))
return 0;
udph = (void *)(ip6h + 1);
if (udph + 1 > data_end)
return 0;
if (src)
return bpf_ntohs(udph->source);
else
return bpf_ntohs(udph->dest);
}
static __always_inline
__u16 get_port_ipv4_tcp(struct xdp_md *ctx, __u64 nh_off, bool src)
{
void *data_end = (void *)(long)ctx->data_end;
void *data = (void *)(long)ctx->data;
struct iphdr *iph = data + nh_off;
struct tcphdr *tcph;
if (iph + 1 > data_end)
return 0;
if (!(iph->protocol == IPPROTO_TCP))
return 0;
tcph = (void *)(iph + 1);
if (tcph + 1 > data_end)
return 0;
if (src)
return bpf_ntohs(tcph->source);
else
return bpf_ntohs(tcph->dest);
}
static __always_inline
__u16 get_port_ipv6_tcp(struct xdp_md *ctx, __u64 nh_off, bool src)
{
void *data_end = (void *)(long)ctx->data_end;
void *data = (void *)(long)ctx->data;
struct ipv6hdr *ip6h = data + nh_off;
struct tcphdr *tcph;
if (ip6h + 1 > data_end)
return 0;
if (!(ip6h->nexthdr == IPPROTO_UDP))
return 0;
tcph = (void *)(ip6h + 1);
if (tcph + 1 > data_end)
return 0;
if (src)
return bpf_ntohs(tcph->source);
else
return bpf_ntohs(tcph->dest);
}
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")
int cpumap_no_touch(struct xdp_md *ctx)
{
__u32 key = bpf_get_smp_processor_id();
struct datarec *rec;
__u32 *cpu_selected;
__u32 cpu_dest = 0;
__u32 key0 = 0;
/* Only use first entry in cpus_available */
cpu_selected = bpf_map_lookup_elem(&cpus_available, &key0);
if (!cpu_selected)
return XDP_ABORTED;
cpu_dest = *cpu_selected;
rec = bpf_map_lookup_elem(&rx_cnt, &key);
if (!rec)
return XDP_PASS;
NO_TEAR_INC(rec->processed);
if (cpu_dest >= nr_cpus) {
NO_TEAR_INC(rec->issue);
return XDP_ABORTED;
}
return bpf_redirect_map(&cpu_map, cpu_dest, 0);
}
SEC("xdp")
int cpumap_touch_data(struct xdp_md *ctx)
{
void *data_end = (void *)(long)ctx->data_end;
void *data = (void *)(long)ctx->data;
__u32 key = bpf_get_smp_processor_id();
struct ethhdr *eth = data;
struct datarec *rec;
__u32 *cpu_selected;
__u32 cpu_dest = 0;
__u32 key0 = 0;
__u16 eth_type;
/* Only use first entry in cpus_available */
cpu_selected = bpf_map_lookup_elem(&cpus_available, &key0);
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;
rec = bpf_map_lookup_elem(&rx_cnt, &key);
if (!rec)
return XDP_PASS;
NO_TEAR_INC(rec->processed);
/* Read packet data, and use it (drop non 802.3 Ethertypes) */
eth_type = eth->h_proto;
if (bpf_ntohs(eth_type) < ETH_P_802_3_MIN) {
NO_TEAR_INC(rec->dropped);
return XDP_DROP;
}
if (cpu_dest >= nr_cpus) {
NO_TEAR_INC(rec->issue);
return XDP_ABORTED;
}
return bpf_redirect_map(&cpu_map, cpu_dest, 0);
}
SEC("xdp")
int cpumap_round_robin(struct xdp_md *ctx)
{
__u32 key = bpf_get_smp_processor_id();
struct datarec *rec;
__u32 cpu_dest = 0;
__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;
rec = bpf_map_lookup_elem(&rx_cnt, &key);
if (!rec)
return XDP_PASS;
NO_TEAR_INC(rec->processed);
if (cpu_dest >= nr_cpus) {
NO_TEAR_INC(rec->issue);
return XDP_ABORTED;
}
return bpf_redirect_map(&cpu_map, cpu_dest, 0);
}
SEC("xdp")
int cpumap_l4_proto(struct xdp_md *ctx)
{
void *data_end = (void *)(long)ctx->data_end;
void *data = (void *)(long)ctx->data;
__u32 key = bpf_get_smp_processor_id();
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_lookup;
__u32 cpu_idx = 0;
rec = bpf_map_lookup_elem(&rx_cnt, &key);
if (!rec)
return XDP_PASS;
NO_TEAR_INC(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 >= nr_cpus) {
NO_TEAR_INC(rec->issue);
return XDP_ABORTED;
}
return bpf_redirect_map(&cpu_map, cpu_dest, 0);
}
SEC("xdp")
int cpumap_l4_filter(struct xdp_md *ctx)
{
void *data_end = (void *)(long)ctx->data_end;
void *data = (void *)(long)ctx->data;
__u32 key = bpf_get_smp_processor_id();
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_lookup;
__u32 cpu_idx = 0;
__u16 dest_port;
rec = bpf_map_lookup_elem(&rx_cnt, &key);
if (!rec)
return XDP_PASS;
NO_TEAR_INC(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_port_ipv4_udp(ctx, l3_offset, false);
if (dest_port == 9) {
NO_TEAR_INC(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 >= nr_cpus) {
NO_TEAR_INC(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.in6_u.u6_addr32[0] + ip6h->daddr.in6_u.u6_addr32[0];
cpu_hash += ip6h->saddr.in6_u.u6_addr32[1] + ip6h->daddr.in6_u.u6_addr32[1];
cpu_hash += ip6h->saddr.in6_u.u6_addr32[2] + ip6h->daddr.in6_u.u6_addr32[2];
cpu_hash += ip6h->saddr.in6_u.u6_addr32[3] + ip6h->daddr.in6_u.u6_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")
int cpumap_l4_hash(struct xdp_md *ctx)
{
void *data_end = (void *)(long)ctx->data_end;
void *data = (void *)(long)ctx->data;
__u32 key = bpf_get_smp_processor_id();
struct ethhdr *eth = data;
struct datarec *rec;
__u16 eth_proto = 0;
__u64 l3_offset = 0;
__u32 cpu_dest = 0;
__u32 cpu_idx = 0;
__u32 *cpu_lookup;
__u32 key0 = 0;
__u32 *cpu_max;
__u32 cpu_hash;
rec = bpf_map_lookup_elem(&rx_cnt, &key);
if (!rec)
return XDP_PASS;
NO_TEAR_INC(rec->processed);
cpu_max = bpf_map_lookup_elem(&cpus_count, &key0);
if (!cpu_max)
return XDP_ABORTED;
if (!(parse_eth(eth, data_end, ð_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 >= nr_cpus) {
NO_TEAR_INC(rec->issue);
return XDP_ABORTED;
}
return bpf_redirect_map(&cpu_map, cpu_dest, 0);
}
static __always_inline
int cpumap_l4_port(struct xdp_md *ctx, bool src)
{
void *data_end = (void *)(long)ctx->data_end;
void *data = (void *)(long)ctx->data;
__u32 key = bpf_get_smp_processor_id();
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_lookup;
__u32 cpu_idx = 0;
__u32 *cpu_max;
__u32 key0 = 0;
__u16 port;
rec = bpf_map_lookup_elem(&rx_cnt, &key);
if (!rec)
return XDP_PASS;
NO_TEAR_INC(rec->processed);
cpu_max = bpf_map_lookup_elem(&cpus_count, &key0);
if (!cpu_max)
return XDP_ABORTED;
if (!(parse_eth(eth, data_end, ð_proto, &l3_offset)))
return XDP_PASS; /* Just skip */
/* Extract L4 source port */
switch (eth_proto) {
case ETH_P_IP:
ip_proto = get_proto_ipv4(ctx, l3_offset);
switch (ip_proto) {
case IPPROTO_TCP:
port = get_port_ipv4_tcp(ctx, l3_offset, src);
break;
case IPPROTO_UDP:
port = get_port_ipv4_udp(ctx, l3_offset, src);
break;
default:
port = 0;
}
break;
case ETH_P_IPV6:
ip_proto = get_proto_ipv6(ctx, l3_offset);
switch (ip_proto) {
case IPPROTO_TCP:
port = get_port_ipv6_tcp(ctx, l3_offset, src);
break;
case IPPROTO_UDP:
port = get_port_ipv6_udp(ctx, l3_offset, src);
break;
default:
port = 0;
}
break;
default:
port = 0;
}
cpu_idx = port % *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 >= nr_cpus) {
NO_TEAR_INC(rec->issue);
return XDP_ABORTED;
}
return bpf_redirect_map(&cpu_map, cpu_dest, 0);
}
SEC("xdp")
int cpumap_l4_sport(struct xdp_md *ctx)
{
return cpumap_l4_port(ctx, true);
}
SEC("xdp")
int cpumap_l4_dport(struct xdp_md *ctx)
{
return cpumap_l4_port(ctx, false);
}
SEC("xdp/cpumap")
int cpumap_redirect(struct xdp_md *ctx)
{
void *data_end = (void *)(long)ctx->data_end;
void *data = (void *)(long)ctx->data;
struct ethhdr *eth = data;
__u64 nh_off;
nh_off = sizeof(*eth);
if (data + nh_off > data_end)
return XDP_DROP;
swap_src_dst_mac(data);
return bpf_redirect_map(&tx_port, 0, 0);
}
SEC("xdp/cpumap")
int cpumap_pass(struct xdp_md *ctx)
{
return XDP_PASS;
}
SEC("xdp/cpumap")
int cpumap_drop(struct xdp_md *ctx)
{
return XDP_DROP;
}
SEC("xdp/devmap")
int redirect_egress_prog(struct xdp_md *ctx)
{
void *data_end = (void *)(long)ctx->data_end;
void *data = (void *)(long)ctx->data;
struct ethhdr *eth = data;
__u64 nh_off;
nh_off = sizeof(*eth);
if (data + nh_off > data_end)
return XDP_DROP;
__builtin_memcpy(eth->h_source, (const char *)tx_mac_addr, ETH_ALEN);
return XDP_PASS;
}
char _license[] SEC("license") = "GPL";