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-rw-r--r--samples/bpf/sockex3_kern.c290
1 files changed, 290 insertions, 0 deletions
diff --git a/samples/bpf/sockex3_kern.c b/samples/bpf/sockex3_kern.c
new file mode 100644
index 000000000000..41ae2fd21b13
--- /dev/null
+++ b/samples/bpf/sockex3_kern.c
@@ -0,0 +1,290 @@
+/* Copyright (c) 2015 PLUMgrid, http://plumgrid.com
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ */
+#include <uapi/linux/bpf.h>
+#include "bpf_helpers.h"
+#include <uapi/linux/in.h>
+#include <uapi/linux/if.h>
+#include <uapi/linux/if_ether.h>
+#include <uapi/linux/ip.h>
+#include <uapi/linux/ipv6.h>
+#include <uapi/linux/if_tunnel.h>
+#include <uapi/linux/mpls.h>
+#define IP_MF 0x2000
+#define IP_OFFSET 0x1FFF
+
+#define PROG(F) SEC("socket/"__stringify(F)) int bpf_func_##F
+
+struct bpf_map_def SEC("maps") jmp_table = {
+ .type = BPF_MAP_TYPE_PROG_ARRAY,
+ .key_size = sizeof(u32),
+ .value_size = sizeof(u32),
+ .max_entries = 8,
+};
+
+#define PARSE_VLAN 1
+#define PARSE_MPLS 2
+#define PARSE_IP 3
+#define PARSE_IPV6 4
+
+/* protocol dispatch routine.
+ * It tail-calls next BPF program depending on eth proto
+ * Note, we could have used:
+ * bpf_tail_call(skb, &jmp_table, proto);
+ * but it would need large prog_array
+ */
+static inline void parse_eth_proto(struct __sk_buff *skb, u32 proto)
+{
+ switch (proto) {
+ case ETH_P_8021Q:
+ case ETH_P_8021AD:
+ bpf_tail_call(skb, &jmp_table, PARSE_VLAN);
+ break;
+ case ETH_P_MPLS_UC:
+ case ETH_P_MPLS_MC:
+ bpf_tail_call(skb, &jmp_table, PARSE_MPLS);
+ break;
+ case ETH_P_IP:
+ bpf_tail_call(skb, &jmp_table, PARSE_IP);
+ break;
+ case ETH_P_IPV6:
+ bpf_tail_call(skb, &jmp_table, PARSE_IPV6);
+ break;
+ }
+}
+
+struct vlan_hdr {
+ __be16 h_vlan_TCI;
+ __be16 h_vlan_encapsulated_proto;
+};
+
+struct flow_keys {
+ __be32 src;
+ __be32 dst;
+ union {
+ __be32 ports;
+ __be16 port16[2];
+ };
+ __u32 ip_proto;
+};
+
+static inline int ip_is_fragment(struct __sk_buff *ctx, __u64 nhoff)
+{
+ return load_half(ctx, nhoff + offsetof(struct iphdr, frag_off))
+ & (IP_MF | IP_OFFSET);
+}
+
+static inline __u32 ipv6_addr_hash(struct __sk_buff *ctx, __u64 off)
+{
+ __u64 w0 = load_word(ctx, off);
+ __u64 w1 = load_word(ctx, off + 4);
+ __u64 w2 = load_word(ctx, off + 8);
+ __u64 w3 = load_word(ctx, off + 12);
+
+ return (__u32)(w0 ^ w1 ^ w2 ^ w3);
+}
+
+struct globals {
+ struct flow_keys flow;
+};
+
+struct bpf_map_def SEC("maps") percpu_map = {
+ .type = BPF_MAP_TYPE_ARRAY,
+ .key_size = sizeof(__u32),
+ .value_size = sizeof(struct globals),
+ .max_entries = 32,
+};
+
+/* user poor man's per_cpu until native support is ready */
+static struct globals *this_cpu_globals(void)
+{
+ u32 key = bpf_get_smp_processor_id();
+
+ return bpf_map_lookup_elem(&percpu_map, &key);
+}
+
+/* some simple stats for user space consumption */
+struct pair {
+ __u64 packets;
+ __u64 bytes;
+};
+
+struct bpf_map_def SEC("maps") hash_map = {
+ .type = BPF_MAP_TYPE_HASH,
+ .key_size = sizeof(struct flow_keys),
+ .value_size = sizeof(struct pair),
+ .max_entries = 1024,
+};
+
+static void update_stats(struct __sk_buff *skb, struct globals *g)
+{
+ struct flow_keys key = g->flow;
+ struct pair *value;
+
+ value = bpf_map_lookup_elem(&hash_map, &key);
+ if (value) {
+ __sync_fetch_and_add(&value->packets, 1);
+ __sync_fetch_and_add(&value->bytes, skb->len);
+ } else {
+ struct pair val = {1, skb->len};
+
+ bpf_map_update_elem(&hash_map, &key, &val, BPF_ANY);
+ }
+}
+
+static __always_inline void parse_ip_proto(struct __sk_buff *skb,
+ struct globals *g, __u32 ip_proto)
+{
+ __u32 nhoff = skb->cb[0];
+ int poff;
+
+ switch (ip_proto) {
+ case IPPROTO_GRE: {
+ struct gre_hdr {
+ __be16 flags;
+ __be16 proto;
+ };
+
+ __u32 gre_flags = load_half(skb,
+ nhoff + offsetof(struct gre_hdr, flags));
+ __u32 gre_proto = load_half(skb,
+ nhoff + offsetof(struct gre_hdr, proto));
+
+ if (gre_flags & (GRE_VERSION|GRE_ROUTING))
+ break;
+
+ nhoff += 4;
+ if (gre_flags & GRE_CSUM)
+ nhoff += 4;
+ if (gre_flags & GRE_KEY)
+ nhoff += 4;
+ if (gre_flags & GRE_SEQ)
+ nhoff += 4;
+
+ skb->cb[0] = nhoff;
+ parse_eth_proto(skb, gre_proto);
+ break;
+ }
+ case IPPROTO_IPIP:
+ parse_eth_proto(skb, ETH_P_IP);
+ break;
+ case IPPROTO_IPV6:
+ parse_eth_proto(skb, ETH_P_IPV6);
+ break;
+ case IPPROTO_TCP:
+ case IPPROTO_UDP:
+ g->flow.ports = load_word(skb, nhoff);
+ case IPPROTO_ICMP:
+ g->flow.ip_proto = ip_proto;
+ update_stats(skb, g);
+ break;
+ default:
+ break;
+ }
+}
+
+PROG(PARSE_IP)(struct __sk_buff *skb)
+{
+ struct globals *g = this_cpu_globals();
+ __u32 nhoff, verlen, ip_proto;
+
+ if (!g)
+ return 0;
+
+ nhoff = skb->cb[0];
+
+ if (unlikely(ip_is_fragment(skb, nhoff)))
+ return 0;
+
+ ip_proto = load_byte(skb, nhoff + offsetof(struct iphdr, protocol));
+
+ if (ip_proto != IPPROTO_GRE) {
+ g->flow.src = load_word(skb, nhoff + offsetof(struct iphdr, saddr));
+ g->flow.dst = load_word(skb, nhoff + offsetof(struct iphdr, daddr));
+ }
+
+ verlen = load_byte(skb, nhoff + 0/*offsetof(struct iphdr, ihl)*/);
+ nhoff += (verlen & 0xF) << 2;
+
+ skb->cb[0] = nhoff;
+ parse_ip_proto(skb, g, ip_proto);
+ return 0;
+}
+
+PROG(PARSE_IPV6)(struct __sk_buff *skb)
+{
+ struct globals *g = this_cpu_globals();
+ __u32 nhoff, ip_proto;
+
+ if (!g)
+ return 0;
+
+ nhoff = skb->cb[0];
+
+ ip_proto = load_byte(skb,
+ nhoff + offsetof(struct ipv6hdr, nexthdr));
+ g->flow.src = ipv6_addr_hash(skb,
+ nhoff + offsetof(struct ipv6hdr, saddr));
+ g->flow.dst = ipv6_addr_hash(skb,
+ nhoff + offsetof(struct ipv6hdr, daddr));
+ nhoff += sizeof(struct ipv6hdr);
+
+ skb->cb[0] = nhoff;
+ parse_ip_proto(skb, g, ip_proto);
+ return 0;
+}
+
+PROG(PARSE_VLAN)(struct __sk_buff *skb)
+{
+ __u32 nhoff, proto;
+
+ nhoff = skb->cb[0];
+
+ proto = load_half(skb, nhoff + offsetof(struct vlan_hdr,
+ h_vlan_encapsulated_proto));
+ nhoff += sizeof(struct vlan_hdr);
+ skb->cb[0] = nhoff;
+
+ parse_eth_proto(skb, proto);
+
+ return 0;
+}
+
+PROG(PARSE_MPLS)(struct __sk_buff *skb)
+{
+ __u32 nhoff, label;
+
+ nhoff = skb->cb[0];
+
+ label = load_word(skb, nhoff);
+ nhoff += sizeof(struct mpls_label);
+ skb->cb[0] = nhoff;
+
+ if (label & MPLS_LS_S_MASK) {
+ __u8 verlen = load_byte(skb, nhoff);
+ if ((verlen & 0xF0) == 4)
+ parse_eth_proto(skb, ETH_P_IP);
+ else
+ parse_eth_proto(skb, ETH_P_IPV6);
+ } else {
+ parse_eth_proto(skb, ETH_P_MPLS_UC);
+ }
+
+ return 0;
+}
+
+SEC("socket/0")
+int main_prog(struct __sk_buff *skb)
+{
+ __u32 nhoff = ETH_HLEN;
+ __u32 proto = load_half(skb, 12);
+
+ skb->cb[0] = nhoff;
+ parse_eth_proto(skb, proto);
+ return 0;
+}
+
+char _license[] SEC("license") = "GPL";
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.