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1/* Copyright (c) 2016,2017 Facebook2 *3 * This program is free software; you can redistribute it and/or4 * modify it under the terms of version 2 of the GNU General Public5 * License as published by the Free Software Foundation.6 */7#include <stddef.h>8#include <string.h>9#include <linux/bpf.h>10#include <linux/if_ether.h>11#include <linux/if_packet.h>12#include <linux/ip.h>13#include <linux/ipv6.h>14#include <linux/in.h>15#include <linux/udp.h>16#include <linux/tcp.h>17#include <linux/pkt_cls.h>18#include <sys/socket.h>19#include <bpf/bpf_helpers.h>20#include <bpf/bpf_endian.h>21#include "test_iptunnel_common.h"22#include "bpf_compiler.h"23 24struct {25 __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);26 __uint(max_entries, 256);27 __type(key, __u32);28 __type(value, __u64);29} rxcnt SEC(".maps");30 31struct {32 __uint(type, BPF_MAP_TYPE_HASH);33 __uint(max_entries, MAX_IPTNL_ENTRIES);34 __type(key, struct vip);35 __type(value, struct iptnl_info);36} vip2tnl SEC(".maps");37 38static __always_inline void count_tx(__u32 protocol)39{40 __u64 *rxcnt_count;41 42 rxcnt_count = bpf_map_lookup_elem(&rxcnt, &protocol);43 if (rxcnt_count)44 *rxcnt_count += 1;45}46 47static __always_inline int get_dport(void *trans_data, void *data_end,48 __u8 protocol)49{50 struct tcphdr *th;51 struct udphdr *uh;52 53 switch (protocol) {54 case IPPROTO_TCP:55 th = (struct tcphdr *)trans_data;56 if (th + 1 > data_end)57 return -1;58 return th->dest;59 case IPPROTO_UDP:60 uh = (struct udphdr *)trans_data;61 if (uh + 1 > data_end)62 return -1;63 return uh->dest;64 default:65 return 0;66 }67}68 69static __always_inline void set_ethhdr(struct ethhdr *new_eth,70 const struct ethhdr *old_eth,71 const struct iptnl_info *tnl,72 __be16 h_proto)73{74 memcpy(new_eth->h_source, old_eth->h_dest, sizeof(new_eth->h_source));75 memcpy(new_eth->h_dest, tnl->dmac, sizeof(new_eth->h_dest));76 new_eth->h_proto = h_proto;77}78 79static __always_inline int handle_ipv4(struct xdp_md *xdp)80{81 void *data_end = (void *)(long)xdp->data_end;82 void *data = (void *)(long)xdp->data;83 struct iptnl_info *tnl;84 struct ethhdr *new_eth;85 struct ethhdr *old_eth;86 struct iphdr *iph = data + sizeof(struct ethhdr);87 __u16 *next_iph;88 __u16 payload_len;89 struct vip vip = {};90 int dport;91 __u32 csum = 0;92 int i;93 94 if (iph + 1 > data_end)95 return XDP_DROP;96 97 dport = get_dport(iph + 1, data_end, iph->protocol);98 if (dport == -1)99 return XDP_DROP;100 101 vip.protocol = iph->protocol;102 vip.family = AF_INET;103 vip.daddr.v4 = iph->daddr;104 vip.dport = dport;105 payload_len = bpf_ntohs(iph->tot_len);106 107 tnl = bpf_map_lookup_elem(&vip2tnl, &vip);108 /* It only does v4-in-v4 */109 if (!tnl || tnl->family != AF_INET)110 return XDP_PASS;111 112 if (bpf_xdp_adjust_head(xdp, 0 - (int)sizeof(struct iphdr)))113 return XDP_DROP;114 115 data = (void *)(long)xdp->data;116 data_end = (void *)(long)xdp->data_end;117 118 new_eth = data;119 iph = data + sizeof(*new_eth);120 old_eth = data + sizeof(*iph);121 122 if (new_eth + 1 > data_end ||123 old_eth + 1 > data_end ||124 iph + 1 > data_end)125 return XDP_DROP;126 127 set_ethhdr(new_eth, old_eth, tnl, bpf_htons(ETH_P_IP));128 129 iph->version = 4;130 iph->ihl = sizeof(*iph) >> 2;131 iph->frag_off = 0;132 iph->protocol = IPPROTO_IPIP;133 iph->check = 0;134 iph->tos = 0;135 iph->tot_len = bpf_htons(payload_len + sizeof(*iph));136 iph->daddr = tnl->daddr.v4;137 iph->saddr = tnl->saddr.v4;138 iph->ttl = 8;139 140 next_iph = (__u16 *)iph;141 __pragma_loop_unroll_full142 for (i = 0; i < sizeof(*iph) >> 1; i++)143 csum += *next_iph++;144 145 iph->check = ~((csum & 0xffff) + (csum >> 16));146 147 count_tx(vip.protocol);148 149 return XDP_TX;150}151 152static __always_inline int handle_ipv6(struct xdp_md *xdp)153{154 void *data_end = (void *)(long)xdp->data_end;155 void *data = (void *)(long)xdp->data;156 struct iptnl_info *tnl;157 struct ethhdr *new_eth;158 struct ethhdr *old_eth;159 struct ipv6hdr *ip6h = data + sizeof(struct ethhdr);160 __u16 payload_len;161 struct vip vip = {};162 int dport;163 164 if (ip6h + 1 > data_end)165 return XDP_DROP;166 167 dport = get_dport(ip6h + 1, data_end, ip6h->nexthdr);168 if (dport == -1)169 return XDP_DROP;170 171 vip.protocol = ip6h->nexthdr;172 vip.family = AF_INET6;173 memcpy(vip.daddr.v6, ip6h->daddr.s6_addr32, sizeof(vip.daddr));174 vip.dport = dport;175 payload_len = ip6h->payload_len;176 177 tnl = bpf_map_lookup_elem(&vip2tnl, &vip);178 /* It only does v6-in-v6 */179 if (!tnl || tnl->family != AF_INET6)180 return XDP_PASS;181 182 if (bpf_xdp_adjust_head(xdp, 0 - (int)sizeof(struct ipv6hdr)))183 return XDP_DROP;184 185 data = (void *)(long)xdp->data;186 data_end = (void *)(long)xdp->data_end;187 188 new_eth = data;189 ip6h = data + sizeof(*new_eth);190 old_eth = data + sizeof(*ip6h);191 192 if (new_eth + 1 > data_end || old_eth + 1 > data_end ||193 ip6h + 1 > data_end)194 return XDP_DROP;195 196 set_ethhdr(new_eth, old_eth, tnl, bpf_htons(ETH_P_IPV6));197 198 ip6h->version = 6;199 ip6h->priority = 0;200 memset(ip6h->flow_lbl, 0, sizeof(ip6h->flow_lbl));201 ip6h->payload_len = bpf_htons(bpf_ntohs(payload_len) + sizeof(*ip6h));202 ip6h->nexthdr = IPPROTO_IPV6;203 ip6h->hop_limit = 8;204 memcpy(ip6h->saddr.s6_addr32, tnl->saddr.v6, sizeof(tnl->saddr.v6));205 memcpy(ip6h->daddr.s6_addr32, tnl->daddr.v6, sizeof(tnl->daddr.v6));206 207 count_tx(vip.protocol);208 209 return XDP_TX;210}211 212SEC("xdp")213int _xdp_tx_iptunnel(struct xdp_md *xdp)214{215 void *data_end = (void *)(long)xdp->data_end;216 void *data = (void *)(long)xdp->data;217 struct ethhdr *eth = data;218 __u16 h_proto;219 220 if (eth + 1 > data_end)221 return XDP_DROP;222 223 h_proto = eth->h_proto;224 225 if (h_proto == bpf_htons(ETH_P_IP))226 return handle_ipv4(xdp);227 else if (h_proto == bpf_htons(ETH_P_IPV6))228 229 return handle_ipv6(xdp);230 else231 return XDP_DROP;232}233 234char _license[] SEC("license") = "GPL";235