samples/bpf/sockex2_kern.c

Source file repositories/reference/linux-study-clean/samples/bpf/sockex2_kern.c

File Facts

System
Linux kernel
Corpus path
samples/bpf/sockex2_kern.c
Extension
.c
Size
4851 bytes
Lines
223
Domain
Support Tooling And Documentation
Bucket
samples
Inferred role
Support Tooling And Documentation: implementation source
Status
source implementation candidate

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

struct vlan_hdr {
	__be16 h_vlan_TCI;
	__be16 h_vlan_encapsulated_proto;
};

struct flow_key_record {
	__be32 src;
	__be32 dst;
	union {
		__be32 ports;
		__be16 port16[2];
	};
	__u16 thoff;
	__u8 ip_proto;
};

static inline int proto_ports_offset(__u64 proto)
{
	switch (proto) {
	case IPPROTO_TCP:
	case IPPROTO_UDP:
	case IPPROTO_ESP:
	case IPPROTO_SCTP:
	case IPPROTO_UDPLITE:
		return 0;
	case IPPROTO_AH:
		return 4;
	default:
		return 0;
	}
}

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);
}

static inline __u64 parse_ip(struct __sk_buff *skb, __u64 nhoff, __u64 *ip_proto,
			     struct flow_key_record *flow)
{
	__u64 verlen;

	if (unlikely(ip_is_fragment(skb, nhoff)))
		*ip_proto = 0;
	else
		*ip_proto = load_byte(skb, nhoff + offsetof(struct iphdr, protocol));

	if (*ip_proto != IPPROTO_GRE) {
		flow->src = load_word(skb, nhoff + offsetof(struct iphdr, saddr));
		flow->dst = load_word(skb, nhoff + offsetof(struct iphdr, daddr));
	}

	verlen = load_byte(skb, nhoff + 0/*offsetof(struct iphdr, ihl)*/);
	if (likely(verlen == 0x45))
		nhoff += 20;
	else
		nhoff += (verlen & 0xF) << 2;

	return nhoff;
}

static inline __u64 parse_ipv6(struct __sk_buff *skb, __u64 nhoff, __u64 *ip_proto,
			       struct flow_key_record *flow)
{
	*ip_proto = load_byte(skb,
			      nhoff + offsetof(struct ipv6hdr, nexthdr));
	flow->src = ipv6_addr_hash(skb,
				   nhoff + offsetof(struct ipv6hdr, saddr));
	flow->dst = ipv6_addr_hash(skb,
				   nhoff + offsetof(struct ipv6hdr, daddr));
	nhoff += sizeof(struct ipv6hdr);

	return nhoff;
}

static inline bool flow_dissector(struct __sk_buff *skb,
				  struct flow_key_record *flow)
{
	__u64 nhoff = ETH_HLEN;

Annotation

Implementation Notes