samples/bpf/sockex2_kern.c

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