164 lines
3.7 KiB
C
164 lines
3.7 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <stddef.h>
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#include <linux/bpf.h>
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#include <linux/in.h>
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#include <linux/if_ether.h>
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#include <linux/ip.h>
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#include <linux/ipv6.h>
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#include <linux/udp.h>
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#include <linux/tcp.h>
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#include <bpf/bpf_endian.h>
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#include <bpf/bpf_helpers.h>
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enum {
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XDP_PORT = 1,
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XDP_PROTO = 4,
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} xdp_map_setup_keys;
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struct {
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__uint(type, BPF_MAP_TYPE_ARRAY);
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__uint(max_entries, 5);
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__type(key, __u32);
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__type(value, __s32);
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} map_xdp_setup SEC(".maps");
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/* RSS hash results: key 0 = hash, key 1 = hash type,
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* key 2 = packet count, key 3 = error count.
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*/
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enum {
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RSS_KEY_HASH = 0,
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RSS_KEY_TYPE = 1,
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RSS_KEY_PKT_CNT = 2,
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RSS_KEY_ERR_CNT = 3,
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};
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struct {
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__uint(type, BPF_MAP_TYPE_ARRAY);
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__type(key, __u32);
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__type(value, __u32);
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__uint(max_entries, 4);
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} map_rss SEC(".maps");
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/* Mirror of enum xdp_rss_hash_type from include/net/xdp.h.
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* Needed because the enum is not part of UAPI headers.
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*/
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enum xdp_rss_hash_type {
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XDP_RSS_L3_IPV4 = 1U << 0,
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XDP_RSS_L3_IPV6 = 1U << 1,
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XDP_RSS_L3_DYNHDR = 1U << 2,
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XDP_RSS_L4 = 1U << 3,
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XDP_RSS_L4_TCP = 1U << 4,
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XDP_RSS_L4_UDP = 1U << 5,
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XDP_RSS_L4_SCTP = 1U << 6,
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XDP_RSS_L4_IPSEC = 1U << 7,
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XDP_RSS_L4_ICMP = 1U << 8,
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};
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extern int bpf_xdp_metadata_rx_hash(const struct xdp_md *ctx, __u32 *hash,
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enum xdp_rss_hash_type *rss_type) __ksym;
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static __always_inline __u16 get_dest_port(void *l4, void *data_end,
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__u8 protocol)
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{
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if (protocol == IPPROTO_UDP) {
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struct udphdr *udp = l4;
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if ((void *)(udp + 1) > data_end)
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return 0;
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return udp->dest;
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} else if (protocol == IPPROTO_TCP) {
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struct tcphdr *tcp = l4;
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if ((void *)(tcp + 1) > data_end)
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return 0;
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return tcp->dest;
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}
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return 0;
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}
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SEC("xdp")
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int xdp_rss_hash(struct xdp_md *ctx)
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{
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void *data_end = (void *)(long)ctx->data_end;
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void *data = (void *)(long)ctx->data;
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enum xdp_rss_hash_type rss_type = 0;
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struct ethhdr *eth = data;
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__u8 l4_proto = 0;
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__u32 hash = 0;
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__u32 key, val;
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void *l4 = NULL;
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__u32 *cnt;
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int ret;
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if ((void *)(eth + 1) > data_end)
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return XDP_PASS;
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if (eth->h_proto == bpf_htons(ETH_P_IP)) {
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struct iphdr *iph = (void *)(eth + 1);
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if ((void *)(iph + 1) > data_end)
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return XDP_PASS;
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l4_proto = iph->protocol;
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l4 = (void *)(iph + 1);
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} else if (eth->h_proto == bpf_htons(ETH_P_IPV6)) {
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struct ipv6hdr *ip6h = (void *)(eth + 1);
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if ((void *)(ip6h + 1) > data_end)
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return XDP_PASS;
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l4_proto = ip6h->nexthdr;
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l4 = (void *)(ip6h + 1);
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}
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if (!l4)
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return XDP_PASS;
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/* Filter on the configured protocol (map_xdp_setup key XDP_PROTO).
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* When set, only process packets matching the requested L4 protocol.
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*/
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key = XDP_PROTO;
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__s32 *proto_cfg = bpf_map_lookup_elem(&map_xdp_setup, &key);
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if (proto_cfg && *proto_cfg != 0 && l4_proto != (__u8)*proto_cfg)
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return XDP_PASS;
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/* Filter on the configured port (map_xdp_setup key XDP_PORT).
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* Only applies to protocols with ports (UDP, TCP).
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*/
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key = XDP_PORT;
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__s32 *port_cfg = bpf_map_lookup_elem(&map_xdp_setup, &key);
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if (port_cfg && *port_cfg != 0) {
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__u16 dest = get_dest_port(l4, data_end, l4_proto);
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if (!dest || bpf_ntohs(dest) != (__u16)*port_cfg)
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return XDP_PASS;
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}
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ret = bpf_xdp_metadata_rx_hash(ctx, &hash, &rss_type);
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if (ret < 0) {
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key = RSS_KEY_ERR_CNT;
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cnt = bpf_map_lookup_elem(&map_rss, &key);
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if (cnt)
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__sync_fetch_and_add(cnt, 1);
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return XDP_PASS;
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}
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key = RSS_KEY_HASH;
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bpf_map_update_elem(&map_rss, &key, &hash, BPF_ANY);
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key = RSS_KEY_TYPE;
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val = (__u32)rss_type;
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bpf_map_update_elem(&map_rss, &key, &val, BPF_ANY);
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key = RSS_KEY_PKT_CNT;
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cnt = bpf_map_lookup_elem(&map_rss, &key);
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if (cnt)
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__sync_fetch_and_add(cnt, 1);
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return XDP_PASS;
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}
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char _license[] SEC("license") = "GPL";
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