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qemu/tools/ebpf/rss.bpf.c
Shreesh Adiga 197a137290 ebpf: fix compatibility with libbpf 1.0+ 
The current implementation fails to load on a system with
libbpf 1.0 and reports that legacy map definitions in 'maps'
section are not supported by libbpf v1.0+. This commit updates
the Makefile to add BTF (-g flag) and appropriately updates
the maps in rss.bpf.c and update the skeleton file in repo.

Signed-off-by: Shreesh Adiga <16567adigashreesh@gmail.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
2023-03-10 17:26:47 +08:00

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/*
* eBPF RSS program
*
* Developed by Daynix Computing LTD (http://www.daynix.com)
*
* Authors:
* Andrew Melnychenko <andrew@daynix.com>
* Yuri Benditovich <yuri.benditovich@daynix.com>
*
* This work is licensed under the terms of the GNU GPL, version 2. See
* the COPYING file in the top-level directory.
*
* Prepare:
* Requires llvm, clang, bpftool, linux kernel tree
*
* Build rss.bpf.skeleton.h:
* make -f Makefile.ebpf clean all
*/
#include <stddef.h>
#include <stdbool.h>
#include <linux/bpf.h>
#include <linux/in.h>
#include <linux/if_ether.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/udp.h>
#include <linux/tcp.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_endian.h>
#include <linux/virtio_net.h>
#define INDIRECTION_TABLE_SIZE 128
#define HASH_CALCULATION_BUFFER_SIZE 36
struct rss_config_t {
__u8 redirect;
__u8 populate_hash;
__u32 hash_types;
__u16 indirections_len;
__u16 default_queue;
} __attribute__((packed));
struct toeplitz_key_data_t {
__u32 leftmost_32_bits;
__u8 next_byte[HASH_CALCULATION_BUFFER_SIZE];
};
struct packet_hash_info_t {
__u8 is_ipv4;
__u8 is_ipv6;
__u8 is_udp;
__u8 is_tcp;
__u8 is_ipv6_ext_src;
__u8 is_ipv6_ext_dst;
__u8 is_fragmented;
__u16 src_port;
__u16 dst_port;
union {
struct {
__be32 in_src;
__be32 in_dst;
};
struct {
struct in6_addr in6_src;
struct in6_addr in6_dst;
struct in6_addr in6_ext_src;
struct in6_addr in6_ext_dst;
};
};
};
struct {
__uint(type, BPF_MAP_TYPE_ARRAY);
__uint(key_size, sizeof(__u32));
__uint(value_size, sizeof(struct rss_config_t));
__uint(max_entries, 1);
} tap_rss_map_configurations SEC(".maps");
struct {
__uint(type, BPF_MAP_TYPE_ARRAY);
__uint(key_size, sizeof(__u32));
__uint(value_size, sizeof(struct toeplitz_key_data_t));
__uint(max_entries, 1);
} tap_rss_map_toeplitz_key SEC(".maps");
struct {
__uint(type, BPF_MAP_TYPE_ARRAY);
__uint(key_size, sizeof(__u32));
__uint(value_size, sizeof(__u16));
__uint(max_entries, INDIRECTION_TABLE_SIZE);
} tap_rss_map_indirection_table SEC(".maps");
static inline void net_rx_rss_add_chunk(__u8 *rss_input, size_t *bytes_written,
const void *ptr, size_t size) {
__builtin_memcpy(&rss_input[*bytes_written], ptr, size);
*bytes_written += size;
}
static inline
void net_toeplitz_add(__u32 *result,
__u8 *input,
__u32 len
, struct toeplitz_key_data_t *key) {
__u32 accumulator = *result;
__u32 leftmost_32_bits = key->leftmost_32_bits;
__u32 byte;
for (byte = 0; byte < HASH_CALCULATION_BUFFER_SIZE; byte++) {
__u8 input_byte = input[byte];
__u8 key_byte = key->next_byte[byte];
__u8 bit;
for (bit = 0; bit < 8; bit++) {
if (input_byte & (1 << 7)) {
accumulator ^= leftmost_32_bits;
}
leftmost_32_bits =
(leftmost_32_bits << 1) | ((key_byte & (1 << 7)) >> 7);
input_byte <<= 1;
key_byte <<= 1;
}
}
*result = accumulator;
}
static inline int ip6_extension_header_type(__u8 hdr_type)
{
switch (hdr_type) {
case IPPROTO_HOPOPTS:
case IPPROTO_ROUTING:
case IPPROTO_FRAGMENT:
case IPPROTO_ICMPV6:
case IPPROTO_NONE:
case IPPROTO_DSTOPTS:
case IPPROTO_MH:
return 1;
default:
return 0;
}
}
/*
* According to
* https://www.iana.org/assignments/ipv6-parameters/ipv6-parameters.xhtml
* we expect that there are would be no more than 11 extensions in IPv6 header,
* also there is 27 TLV options for Destination and Hop-by-hop extensions.
* Need to choose reasonable amount of maximum extensions/options we may
* check to find ext src/dst.
*/
#define IP6_EXTENSIONS_COUNT 11
#define IP6_OPTIONS_COUNT 30
static inline int parse_ipv6_ext(struct __sk_buff *skb,
struct packet_hash_info_t *info,
__u8 *l4_protocol, size_t *l4_offset)
{
int err = 0;
if (!ip6_extension_header_type(*l4_protocol)) {
return 0;
}
struct ipv6_opt_hdr ext_hdr = {};
for (unsigned int i = 0; i < IP6_EXTENSIONS_COUNT; ++i) {
err = bpf_skb_load_bytes_relative(skb, *l4_offset, &ext_hdr,
sizeof(ext_hdr), BPF_HDR_START_NET);
if (err) {
goto error;
}
if (*l4_protocol == IPPROTO_ROUTING) {
struct ipv6_rt_hdr ext_rt = {};
err = bpf_skb_load_bytes_relative(skb, *l4_offset, &ext_rt,
sizeof(ext_rt), BPF_HDR_START_NET);
if (err) {
goto error;
}
if ((ext_rt.type == IPV6_SRCRT_TYPE_2) &&
(ext_rt.hdrlen == sizeof(struct in6_addr) / 8) &&
(ext_rt.segments_left == 1)) {
err = bpf_skb_load_bytes_relative(skb,
*l4_offset + offsetof(struct rt2_hdr, addr),
&info->in6_ext_dst, sizeof(info->in6_ext_dst),
BPF_HDR_START_NET);
if (err) {
goto error;
}
info->is_ipv6_ext_dst = 1;
}
} else if (*l4_protocol == IPPROTO_DSTOPTS) {
struct ipv6_opt_t {
__u8 type;
__u8 length;
} __attribute__((packed)) opt = {};
size_t opt_offset = sizeof(ext_hdr);
for (unsigned int j = 0; j < IP6_OPTIONS_COUNT; ++j) {
err = bpf_skb_load_bytes_relative(skb, *l4_offset + opt_offset,
&opt, sizeof(opt), BPF_HDR_START_NET);
if (err) {
goto error;
}
if (opt.type == IPV6_TLV_HAO) {
err = bpf_skb_load_bytes_relative(skb,
*l4_offset + opt_offset
+ offsetof(struct ipv6_destopt_hao, addr),
&info->in6_ext_src, sizeof(info->in6_ext_src),
BPF_HDR_START_NET);
if (err) {
goto error;
}
info->is_ipv6_ext_src = 1;
break;
}
opt_offset += (opt.type == IPV6_TLV_PAD1) ?
1 : opt.length + sizeof(opt);
if (opt_offset + 1 >= ext_hdr.hdrlen * 8) {
break;
}
}
} else if (*l4_protocol == IPPROTO_FRAGMENT) {
info->is_fragmented = true;
}
*l4_protocol = ext_hdr.nexthdr;
*l4_offset += (ext_hdr.hdrlen + 1) * 8;
if (!ip6_extension_header_type(ext_hdr.nexthdr)) {
return 0;
}
}
return 0;
error:
return err;
}
static __be16 parse_eth_type(struct __sk_buff *skb)
{
unsigned int offset = 12;
__be16 ret = 0;
int err = 0;
err = bpf_skb_load_bytes_relative(skb, offset, &ret, sizeof(ret),
BPF_HDR_START_MAC);
if (err) {
return 0;
}
switch (bpf_ntohs(ret)) {
case ETH_P_8021AD:
offset += 4;
case ETH_P_8021Q:
offset += 4;
err = bpf_skb_load_bytes_relative(skb, offset, &ret, sizeof(ret),
BPF_HDR_START_MAC);
default:
break;
}
if (err) {
return 0;
}
return ret;
}
static inline int parse_packet(struct __sk_buff *skb,
struct packet_hash_info_t *info)
{
int err = 0;
if (!info || !skb) {
return -1;
}
size_t l4_offset = 0;
__u8 l4_protocol = 0;
__u16 l3_protocol = bpf_ntohs(parse_eth_type(skb));
if (l3_protocol == 0) {
err = -1;
goto error;
}
if (l3_protocol == ETH_P_IP) {
info->is_ipv4 = 1;
struct iphdr ip = {};
err = bpf_skb_load_bytes_relative(skb, 0, &ip, sizeof(ip),
BPF_HDR_START_NET);
if (err) {
goto error;
}
info->in_src = ip.saddr;
info->in_dst = ip.daddr;
info->is_fragmented = !!ip.frag_off;
l4_protocol = ip.protocol;
l4_offset = ip.ihl * 4;
} else if (l3_protocol == ETH_P_IPV6) {
info->is_ipv6 = 1;
struct ipv6hdr ip6 = {};
err = bpf_skb_load_bytes_relative(skb, 0, &ip6, sizeof(ip6),
BPF_HDR_START_NET);
if (err) {
goto error;
}
info->in6_src = ip6.saddr;
info->in6_dst = ip6.daddr;
l4_protocol = ip6.nexthdr;
l4_offset = sizeof(ip6);
err = parse_ipv6_ext(skb, info, &l4_protocol, &l4_offset);
if (err) {
goto error;
}
}
if (l4_protocol != 0 && !info->is_fragmented) {
if (l4_protocol == IPPROTO_TCP) {
info->is_tcp = 1;
struct tcphdr tcp = {};
err = bpf_skb_load_bytes_relative(skb, l4_offset, &tcp, sizeof(tcp),
BPF_HDR_START_NET);
if (err) {
goto error;
}
info->src_port = tcp.source;
info->dst_port = tcp.dest;
} else if (l4_protocol == IPPROTO_UDP) { /* TODO: add udplite? */
info->is_udp = 1;
struct udphdr udp = {};
err = bpf_skb_load_bytes_relative(skb, l4_offset, &udp, sizeof(udp),
BPF_HDR_START_NET);
if (err) {
goto error;
}
info->src_port = udp.source;
info->dst_port = udp.dest;
}
}
return 0;
error:
return err;
}
static inline __u32 calculate_rss_hash(struct __sk_buff *skb,
struct rss_config_t *config, struct toeplitz_key_data_t *toe)
{
__u8 rss_input[HASH_CALCULATION_BUFFER_SIZE] = {};
size_t bytes_written = 0;
__u32 result = 0;
int err = 0;
struct packet_hash_info_t packet_info = {};
err = parse_packet(skb, &packet_info);
if (err) {
return 0;
}
if (packet_info.is_ipv4) {
if (packet_info.is_tcp &&
config->hash_types & VIRTIO_NET_RSS_HASH_TYPE_TCPv4) {
net_rx_rss_add_chunk(rss_input, &bytes_written,
&packet_info.in_src,
sizeof(packet_info.in_src));
net_rx_rss_add_chunk(rss_input, &bytes_written,
&packet_info.in_dst,
sizeof(packet_info.in_dst));
net_rx_rss_add_chunk(rss_input, &bytes_written,
&packet_info.src_port,
sizeof(packet_info.src_port));
net_rx_rss_add_chunk(rss_input, &bytes_written,
&packet_info.dst_port,
sizeof(packet_info.dst_port));
} else if (packet_info.is_udp &&
config->hash_types & VIRTIO_NET_RSS_HASH_TYPE_UDPv4) {
net_rx_rss_add_chunk(rss_input, &bytes_written,
&packet_info.in_src,
sizeof(packet_info.in_src));
net_rx_rss_add_chunk(rss_input, &bytes_written,
&packet_info.in_dst,
sizeof(packet_info.in_dst));
net_rx_rss_add_chunk(rss_input, &bytes_written,
&packet_info.src_port,
sizeof(packet_info.src_port));
net_rx_rss_add_chunk(rss_input, &bytes_written,
&packet_info.dst_port,
sizeof(packet_info.dst_port));
} else if (config->hash_types & VIRTIO_NET_RSS_HASH_TYPE_IPv4) {
net_rx_rss_add_chunk(rss_input, &bytes_written,
&packet_info.in_src,
sizeof(packet_info.in_src));
net_rx_rss_add_chunk(rss_input, &bytes_written,
&packet_info.in_dst,
sizeof(packet_info.in_dst));
}
} else if (packet_info.is_ipv6) {
if (packet_info.is_tcp &&
config->hash_types & VIRTIO_NET_RSS_HASH_TYPE_TCPv6) {
if (packet_info.is_ipv6_ext_src &&
config->hash_types & VIRTIO_NET_RSS_HASH_TYPE_TCP_EX) {
net_rx_rss_add_chunk(rss_input, &bytes_written,
&packet_info.in6_ext_src,
sizeof(packet_info.in6_ext_src));
} else {
net_rx_rss_add_chunk(rss_input, &bytes_written,
&packet_info.in6_src,
sizeof(packet_info.in6_src));
}
if (packet_info.is_ipv6_ext_dst &&
config->hash_types & VIRTIO_NET_RSS_HASH_TYPE_TCP_EX) {
net_rx_rss_add_chunk(rss_input, &bytes_written,
&packet_info.in6_ext_dst,
sizeof(packet_info.in6_ext_dst));
} else {
net_rx_rss_add_chunk(rss_input, &bytes_written,
&packet_info.in6_dst,
sizeof(packet_info.in6_dst));
}
net_rx_rss_add_chunk(rss_input, &bytes_written,
&packet_info.src_port,
sizeof(packet_info.src_port));
net_rx_rss_add_chunk(rss_input, &bytes_written,
&packet_info.dst_port,
sizeof(packet_info.dst_port));
} else if (packet_info.is_udp &&
config->hash_types & VIRTIO_NET_RSS_HASH_TYPE_UDPv6) {
if (packet_info.is_ipv6_ext_src &&
config->hash_types & VIRTIO_NET_RSS_HASH_TYPE_UDP_EX) {
net_rx_rss_add_chunk(rss_input, &bytes_written,
&packet_info.in6_ext_src,
sizeof(packet_info.in6_ext_src));
} else {
net_rx_rss_add_chunk(rss_input, &bytes_written,
&packet_info.in6_src,
sizeof(packet_info.in6_src));
}
if (packet_info.is_ipv6_ext_dst &&
config->hash_types & VIRTIO_NET_RSS_HASH_TYPE_UDP_EX) {
net_rx_rss_add_chunk(rss_input, &bytes_written,
&packet_info.in6_ext_dst,
sizeof(packet_info.in6_ext_dst));
} else {
net_rx_rss_add_chunk(rss_input, &bytes_written,
&packet_info.in6_dst,
sizeof(packet_info.in6_dst));
}
net_rx_rss_add_chunk(rss_input, &bytes_written,
&packet_info.src_port,
sizeof(packet_info.src_port));
net_rx_rss_add_chunk(rss_input, &bytes_written,
&packet_info.dst_port,
sizeof(packet_info.dst_port));
} else if (config->hash_types & VIRTIO_NET_RSS_HASH_TYPE_IPv6) {
if (packet_info.is_ipv6_ext_src &&
config->hash_types & VIRTIO_NET_RSS_HASH_TYPE_IP_EX) {
net_rx_rss_add_chunk(rss_input, &bytes_written,
&packet_info.in6_ext_src,
sizeof(packet_info.in6_ext_src));
} else {
net_rx_rss_add_chunk(rss_input, &bytes_written,
&packet_info.in6_src,
sizeof(packet_info.in6_src));
}
if (packet_info.is_ipv6_ext_dst &&
config->hash_types & VIRTIO_NET_RSS_HASH_TYPE_IP_EX) {
net_rx_rss_add_chunk(rss_input, &bytes_written,
&packet_info.in6_ext_dst,
sizeof(packet_info.in6_ext_dst));
} else {
net_rx_rss_add_chunk(rss_input, &bytes_written,
&packet_info.in6_dst,
sizeof(packet_info.in6_dst));
}
}
}
if (bytes_written) {
net_toeplitz_add(&result, rss_input, bytes_written, toe);
}
return result;
}
SEC("tun_rss_steering")
int tun_rss_steering_prog(struct __sk_buff *skb)
{
struct rss_config_t *config;
struct toeplitz_key_data_t *toe;
__u32 key = 0;
__u32 hash = 0;
config = bpf_map_lookup_elem(&tap_rss_map_configurations, &key);
toe = bpf_map_lookup_elem(&tap_rss_map_toeplitz_key, &key);
if (config && toe) {
if (!config->redirect) {
return config->default_queue;
}
hash = calculate_rss_hash(skb, config, toe);
if (hash) {
__u32 table_idx = hash % config->indirections_len;
__u16 *queue = 0;
queue = bpf_map_lookup_elem(&tap_rss_map_indirection_table,
&table_idx);
if (queue) {
return *queue;
}
}
return config->default_queue;
}
return -1;
}
char _license[] SEC("license") = "GPL v2";
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