tools/testing/selftests/bpf/progs/test_xdp_loop.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 // Copyright (c) 2019 Facebook
   3 #include <stddef.h>
   4 #include <string.h>
   5 #include <linux/bpf.h>
   6 #include <linux/if_ether.h>
   7 #include <linux/if_packet.h>
   8 #include <linux/ip.h>
   9 #include <linux/ipv6.h>
  10 #include <linux/in.h>
  11 #include <linux/udp.h>
  12 #include <linux/tcp.h>
  13 #include <linux/pkt_cls.h>
  14 #include <sys/socket.h>
  15 #include <bpf/bpf_helpers.h>
  16 #include <bpf/bpf_endian.h>
  17 #include "test_iptunnel_common.h"
  18
  19 int _version SEC("version") = 1;
  20
  21 struct {
  22         __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
  23         __uint(max_entries, 256);
  24         __type(key, __u32);
  25         __type(value, __u64);
  26 } rxcnt SEC(".maps");
  27
  28 struct {
  29         __uint(type, BPF_MAP_TYPE_HASH);
  30         __uint(max_entries, MAX_IPTNL_ENTRIES);
  31         __type(key, struct vip);
  32         __type(value, struct iptnl_info);
  33 } vip2tnl SEC(".maps");
  34
  35 static __always_inline void count_tx(__u32 protocol)
  36 {
  37         __u64 *rxcnt_count;
  38
  39         rxcnt_count = bpf_map_lookup_elem(&rxcnt, &protocol);
  40         if (rxcnt_count)
  41                 *rxcnt_count += 1;
  42 }
  43
  44 static __always_inline int get_dport(void *trans_data, void *data_end,
  45                                      __u8 protocol)
  46 {
  47         struct tcphdr *th;
  48         struct udphdr *uh;
  49
  50         switch (protocol) {
  51         case IPPROTO_TCP:
  52                 th = (struct tcphdr *)trans_data;
  53                 if (th + 1 > data_end)
  54                         return -1;
  55                 return th->dest;
  56         case IPPROTO_UDP:
  57                 uh = (struct udphdr *)trans_data;
  58                 if (uh + 1 > data_end)
  59                         return -1;
  60                 return uh->dest;
  61         default:
  62                 return 0;
  63         }
  64 }
  65
  66 static __always_inline void set_ethhdr(struct ethhdr *new_eth,
  67                                        const struct ethhdr *old_eth,
  68                                        const struct iptnl_info *tnl,
  69                                        __be16 h_proto)
  70 {
  71         memcpy(new_eth->h_source, old_eth->h_dest, sizeof(new_eth->h_source));
  72         memcpy(new_eth->h_dest, tnl->dmac, sizeof(new_eth->h_dest));
  73         new_eth->h_proto = h_proto;
  74 }
  75
  76 static __always_inline int handle_ipv4(struct xdp_md *xdp)
  77 {
  78         void *data_end = (void *)(long)xdp->data_end;
  79         void *data = (void *)(long)xdp->data;
  80         struct iptnl_info *tnl;
  81         struct ethhdr *new_eth;
  82         struct ethhdr *old_eth;
  83         struct iphdr *iph = data + sizeof(struct ethhdr);
  84         __u16 *next_iph;
  85         __u16 payload_len;
  86         struct vip vip = {};
  87         int dport;
  88         __u32 csum = 0;
  89         int i;
  90
  91         if (iph + 1 > data_end)
  92                 return XDP_DROP;
  93
  94         dport = get_dport(iph + 1, data_end, iph->protocol);
  95         if (dport == -1)
  96                 return XDP_DROP;
  97
  98         vip.protocol = iph->protocol;
  99         vip.family = AF_INET;
 100         vip.daddr.v4 = iph->daddr;
 101         vip.dport = dport;
 102         payload_len = bpf_ntohs(iph->tot_len);
 103
 104         tnl = bpf_map_lookup_elem(&vip2tnl, &vip);
 105         /* It only does v4-in-v4 */
 106         if (!tnl || tnl->family != AF_INET)
 107                 return XDP_PASS;
 108
 109         if (bpf_xdp_adjust_head(xdp, 0 - (int)sizeof(struct iphdr)))
 110                 return XDP_DROP;
 111
 112         data = (void *)(long)xdp->data;
 113         data_end = (void *)(long)xdp->data_end;
 114
 115         new_eth = data;
 116         iph = data + sizeof(*new_eth);
 117         old_eth = data + sizeof(*iph);
 118
 119         if (new_eth + 1 > data_end ||
 120             old_eth + 1 > data_end ||
 121             iph + 1 > data_end)
 122                 return XDP_DROP;
 123
 124         set_ethhdr(new_eth, old_eth, tnl, bpf_htons(ETH_P_IP));
 125
 126         iph->version = 4;
 127         iph->ihl = sizeof(*iph) >> 2;
 128         iph->frag_off = 0;
 129         iph->protocol = IPPROTO_IPIP;
 130         iph->check = 0;
 131         iph->tos = 0;
 132         iph->tot_len = bpf_htons(payload_len + sizeof(*iph));
 133         iph->daddr = tnl->daddr.v4;
 134         iph->saddr = tnl->saddr.v4;
 135         iph->ttl = 8;
 136
 137         next_iph = (__u16 *)iph;
 138 #pragma clang loop unroll(disable)
 139         for (i = 0; i < sizeof(*iph) >> 1; i++)
 140                 csum += *next_iph++;
 141
 142         iph->check = ~((csum & 0xffff) + (csum >> 16));
 143
 144         count_tx(vip.protocol);
 145
 146         return XDP_TX;
 147 }
 148
 149 static __always_inline int handle_ipv6(struct xdp_md *xdp)
 150 {
 151         void *data_end = (void *)(long)xdp->data_end;
 152         void *data = (void *)(long)xdp->data;
 153         struct iptnl_info *tnl;
 154         struct ethhdr *new_eth;
 155         struct ethhdr *old_eth;
 156         struct ipv6hdr *ip6h = data + sizeof(struct ethhdr);
 157         __u16 payload_len;
 158         struct vip vip = {};
 159         int dport;
 160
 161         if (ip6h + 1 > data_end)
 162                 return XDP_DROP;
 163
 164         dport = get_dport(ip6h + 1, data_end, ip6h->nexthdr);
 165         if (dport == -1)
 166                 return XDP_DROP;
 167
 168         vip.protocol = ip6h->nexthdr;
 169         vip.family = AF_INET6;
 170         memcpy(vip.daddr.v6, ip6h->daddr.s6_addr32, sizeof(vip.daddr));
 171         vip.dport = dport;
 172         payload_len = ip6h->payload_len;
 173
 174         tnl = bpf_map_lookup_elem(&vip2tnl, &vip);
 175         /* It only does v6-in-v6 */
 176         if (!tnl || tnl->family != AF_INET6)
 177                 return XDP_PASS;
 178
 179         if (bpf_xdp_adjust_head(xdp, 0 - (int)sizeof(struct ipv6hdr)))
 180                 return XDP_DROP;
 181
 182         data = (void *)(long)xdp->data;
 183         data_end = (void *)(long)xdp->data_end;
 184
 185         new_eth = data;
 186         ip6h = data + sizeof(*new_eth);
 187         old_eth = data + sizeof(*ip6h);
 188
 189         if (new_eth + 1 > data_end || old_eth + 1 > data_end ||
 190             ip6h + 1 > data_end)
 191                 return XDP_DROP;
 192
 193         set_ethhdr(new_eth, old_eth, tnl, bpf_htons(ETH_P_IPV6));
 194
 195         ip6h->version = 6;
 196         ip6h->priority = 0;
 197         memset(ip6h->flow_lbl, 0, sizeof(ip6h->flow_lbl));
 198         ip6h->payload_len = bpf_htons(bpf_ntohs(payload_len) + sizeof(*ip6h));
 199         ip6h->nexthdr = IPPROTO_IPV6;
 200         ip6h->hop_limit = 8;
 201         memcpy(ip6h->saddr.s6_addr32, tnl->saddr.v6, sizeof(tnl->saddr.v6));
 202         memcpy(ip6h->daddr.s6_addr32, tnl->daddr.v6, sizeof(tnl->daddr.v6));
 203
 204         count_tx(vip.protocol);
 205
 206         return XDP_TX;
 207 }
 208
 209 SEC("xdp_tx_iptunnel")
 210 int _xdp_tx_iptunnel(struct xdp_md *xdp)
 211 {
 212         void *data_end = (void *)(long)xdp->data_end;
 213         void *data = (void *)(long)xdp->data;
 214         struct ethhdr *eth = data;
 215         __u16 h_proto;
 216
 217         if (eth + 1 > data_end)
 218                 return XDP_DROP;
 219
 220         h_proto = eth->h_proto;
 221
 222         if (h_proto == bpf_htons(ETH_P_IP))
 223                 return handle_ipv4(xdp);
 224         else if (h_proto == bpf_htons(ETH_P_IPV6))
 225
 226                 return handle_ipv6(xdp);
 227         else
 228                 return XDP_DROP;
 229 }
 230
 231 char _license[] SEC("license") = "GPL";