samples/bpf/sockex2_kern.c

   1 #include <uapi/linux/bpf.h>
   2 #include <uapi/linux/in.h>
   3 #include <uapi/linux/if.h>
   4 #include <uapi/linux/if_ether.h>
   5 #include <uapi/linux/ip.h>
   6 #include <uapi/linux/ipv6.h>
   7 #include <uapi/linux/if_tunnel.h>
   8 #include <bpf/bpf_helpers.h>
   9 #include "bpf_legacy.h"
  10 #define IP_MF           0x2000
  11 #define IP_OFFSET       0x1FFF
  12
  13 struct vlan_hdr {
  14         __be16 h_vlan_TCI;
  15         __be16 h_vlan_encapsulated_proto;
  16 };
  17
  18 struct flow_key_record {
  19         __be32 src;
  20         __be32 dst;
  21         union {
  22                 __be32 ports;
  23                 __be16 port16[2];
  24         };
  25         __u16 thoff;
  26         __u8 ip_proto;
  27 };
  28
  29 static inline int proto_ports_offset(__u64 proto)
  30 {
  31         switch (proto) {
  32         case IPPROTO_TCP:
  33         case IPPROTO_UDP:
  34         case IPPROTO_DCCP:
  35         case IPPROTO_ESP:
  36         case IPPROTO_SCTP:
  37         case IPPROTO_UDPLITE:
  38                 return 0;
  39         case IPPROTO_AH:
  40                 return 4;
  41         default:
  42                 return 0;
  43         }
  44 }
  45
  46 static inline int ip_is_fragment(struct __sk_buff *ctx, __u64 nhoff)
  47 {
  48         return load_half(ctx, nhoff + offsetof(struct iphdr, frag_off))
  49                 & (IP_MF | IP_OFFSET);
  50 }
  51
  52 static inline __u32 ipv6_addr_hash(struct __sk_buff *ctx, __u64 off)
  53 {
  54         __u64 w0 = load_word(ctx, off);
  55         __u64 w1 = load_word(ctx, off + 4);
  56         __u64 w2 = load_word(ctx, off + 8);
  57         __u64 w3 = load_word(ctx, off + 12);
  58
  59         return (__u32)(w0 ^ w1 ^ w2 ^ w3);
  60 }
  61
  62 static inline __u64 parse_ip(struct __sk_buff *skb, __u64 nhoff, __u64 *ip_proto,
  63                              struct flow_key_record *flow)
  64 {
  65         __u64 verlen;
  66
  67         if (unlikely(ip_is_fragment(skb, nhoff)))
  68                 *ip_proto = 0;
  69         else
  70                 *ip_proto = load_byte(skb, nhoff + offsetof(struct iphdr, protocol));
  71
  72         if (*ip_proto != IPPROTO_GRE) {
  73                 flow->src = load_word(skb, nhoff + offsetof(struct iphdr, saddr));
  74                 flow->dst = load_word(skb, nhoff + offsetof(struct iphdr, daddr));
  75         }
  76
  77         verlen = load_byte(skb, nhoff + 0/*offsetof(struct iphdr, ihl)*/);
  78         if (likely(verlen == 0x45))
  79                 nhoff += 20;
  80         else
  81                 nhoff += (verlen & 0xF) << 2;
  82
  83         return nhoff;
  84 }
  85
  86 static inline __u64 parse_ipv6(struct __sk_buff *skb, __u64 nhoff, __u64 *ip_proto,
  87                                struct flow_key_record *flow)
  88 {
  89         *ip_proto = load_byte(skb,
  90                               nhoff + offsetof(struct ipv6hdr, nexthdr));
  91         flow->src = ipv6_addr_hash(skb,
  92                                    nhoff + offsetof(struct ipv6hdr, saddr));
  93         flow->dst = ipv6_addr_hash(skb,
  94                                    nhoff + offsetof(struct ipv6hdr, daddr));
  95         nhoff += sizeof(struct ipv6hdr);
  96
  97         return nhoff;
  98 }
  99
 100 static inline bool flow_dissector(struct __sk_buff *skb,
 101                                   struct flow_key_record *flow)
 102 {
 103         __u64 nhoff = ETH_HLEN;
 104         __u64 ip_proto;
 105         __u64 proto = load_half(skb, 12);
 106         int poff;
 107
 108         if (proto == ETH_P_8021AD) {
 109                 proto = load_half(skb, nhoff + offsetof(struct vlan_hdr,
 110                                                         h_vlan_encapsulated_proto));
 111                 nhoff += sizeof(struct vlan_hdr);
 112         }
 113
 114         if (proto == ETH_P_8021Q) {
 115                 proto = load_half(skb, nhoff + offsetof(struct vlan_hdr,
 116                                                         h_vlan_encapsulated_proto));
 117                 nhoff += sizeof(struct vlan_hdr);
 118         }
 119
 120         if (likely(proto == ETH_P_IP))
 121                 nhoff = parse_ip(skb, nhoff, &ip_proto, flow);
 122         else if (proto == ETH_P_IPV6)
 123                 nhoff = parse_ipv6(skb, nhoff, &ip_proto, flow);
 124         else
 125                 return false;
 126
 127         switch (ip_proto) {
 128         case IPPROTO_GRE: {
 129                 struct gre_hdr {
 130                         __be16 flags;
 131                         __be16 proto;
 132                 };
 133
 134                 __u64 gre_flags = load_half(skb,
 135                                             nhoff + offsetof(struct gre_hdr, flags));
 136                 __u64 gre_proto = load_half(skb,
 137                                             nhoff + offsetof(struct gre_hdr, proto));
 138
 139                 if (gre_flags & (GRE_VERSION|GRE_ROUTING))
 140                         break;
 141
 142                 proto = gre_proto;
 143                 nhoff += 4;
 144                 if (gre_flags & GRE_CSUM)
 145                         nhoff += 4;
 146                 if (gre_flags & GRE_KEY)
 147                         nhoff += 4;
 148                 if (gre_flags & GRE_SEQ)
 149                         nhoff += 4;
 150
 151                 if (proto == ETH_P_8021Q) {
 152                         proto = load_half(skb,
 153                                           nhoff + offsetof(struct vlan_hdr,
 154                                                            h_vlan_encapsulated_proto));
 155                         nhoff += sizeof(struct vlan_hdr);
 156                 }
 157
 158                 if (proto == ETH_P_IP)
 159                         nhoff = parse_ip(skb, nhoff, &ip_proto, flow);
 160                 else if (proto == ETH_P_IPV6)
 161                         nhoff = parse_ipv6(skb, nhoff, &ip_proto, flow);
 162                 else
 163                         return false;
 164                 break;
 165         }
 166         case IPPROTO_IPIP:
 167                 nhoff = parse_ip(skb, nhoff, &ip_proto, flow);
 168                 break;
 169         case IPPROTO_IPV6:
 170                 nhoff = parse_ipv6(skb, nhoff, &ip_proto, flow);
 171                 break;
 172         default:
 173                 break;
 174         }
 175
 176         flow->ip_proto = ip_proto;
 177         poff = proto_ports_offset(ip_proto);
 178         if (poff >= 0) {
 179                 nhoff += poff;
 180                 flow->ports = load_word(skb, nhoff);
 181         }
 182
 183         flow->thoff = (__u16) nhoff;
 184
 185         return true;
 186 }
 187
 188 struct pair {
 189         long packets;
 190         long bytes;
 191 };
 192
 193 struct {
 194         __uint(type, BPF_MAP_TYPE_HASH);
 195         __type(key, __be32);
 196         __type(value, struct pair);
 197         __uint(max_entries, 1024);
 198 } hash_map SEC(".maps");
 199
 200 SEC("socket2")
 201 int bpf_prog2(struct __sk_buff *skb)
 202 {
 203         struct flow_key_record flow = {};
 204         struct pair *value;
 205         u32 key;
 206
 207         if (!flow_dissector(skb, &flow))
 208                 return 0;
 209
 210         key = flow.dst;
 211         value = bpf_map_lookup_elem(&hash_map, &key);
 212         if (value) {
 213                 __sync_fetch_and_add(&value->packets, 1);
 214                 __sync_fetch_and_add(&value->bytes, skb->len);
 215         } else {
 216                 struct pair val = {1, skb->len};
 217
 218                 bpf_map_update_elem(&hash_map, &key, &val, BPF_ANY);
 219         }
 220         return 0;
 221 }
 222
 223 char _license[] SEC("license") = "GPL";