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Linux/tools/testing/selftests/bpf/test_l4lb.c

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  1 /* Copyright (c) 2017 Facebook
  2  *
  3  * This program is free software; you can redistribute it and/or
  4  * modify it under the terms of version 2 of the GNU General Public
  5  * License as published by the Free Software Foundation.
  6  */
  7 #include <stddef.h>
  8 #include <stdbool.h>
  9 #include <string.h>
 10 #include <linux/pkt_cls.h>
 11 #include <linux/bpf.h>
 12 #include <linux/in.h>
 13 #include <linux/if_ether.h>
 14 #include <linux/ip.h>
 15 #include <linux/ipv6.h>
 16 #include <linux/icmp.h>
 17 #include <linux/icmpv6.h>
 18 #include <linux/tcp.h>
 19 #include <linux/udp.h>
 20 #include "bpf_helpers.h"
 21 #include "test_iptunnel_common.h"
 22 #include "bpf_endian.h"
 23 
 24 int _version SEC("version") = 1;
 25 
 26 static inline __u32 rol32(__u32 word, unsigned int shift)
 27 {
 28         return (word << shift) | (word >> ((-shift) & 31));
 29 }
 30 
 31 /* copy paste of jhash from kernel sources to make sure llvm
 32  * can compile it into valid sequence of bpf instructions
 33  */
 34 #define __jhash_mix(a, b, c)                    \
 35 {                                               \
 36         a -= c;  a ^= rol32(c, 4);  c += b;     \
 37         b -= a;  b ^= rol32(a, 6);  a += c;     \
 38         c -= b;  c ^= rol32(b, 8);  b += a;     \
 39         a -= c;  a ^= rol32(c, 16); c += b;     \
 40         b -= a;  b ^= rol32(a, 19); a += c;     \
 41         c -= b;  c ^= rol32(b, 4);  b += a;     \
 42 }
 43 
 44 #define __jhash_final(a, b, c)                  \
 45 {                                               \
 46         c ^= b; c -= rol32(b, 14);              \
 47         a ^= c; a -= rol32(c, 11);              \
 48         b ^= a; b -= rol32(a, 25);              \
 49         c ^= b; c -= rol32(b, 16);              \
 50         a ^= c; a -= rol32(c, 4);               \
 51         b ^= a; b -= rol32(a, 14);              \
 52         c ^= b; c -= rol32(b, 24);              \
 53 }
 54 
 55 #define JHASH_INITVAL           0xdeadbeef
 56 
 57 typedef unsigned int u32;
 58 
 59 static inline u32 jhash(const void *key, u32 length, u32 initval)
 60 {
 61         u32 a, b, c;
 62         const unsigned char *k = key;
 63 
 64         a = b = c = JHASH_INITVAL + length + initval;
 65 
 66         while (length > 12) {
 67                 a += *(u32 *)(k);
 68                 b += *(u32 *)(k + 4);
 69                 c += *(u32 *)(k + 8);
 70                 __jhash_mix(a, b, c);
 71                 length -= 12;
 72                 k += 12;
 73         }
 74         switch (length) {
 75         case 12: c += (u32)k[11]<<24;
 76         case 11: c += (u32)k[10]<<16;
 77         case 10: c += (u32)k[9]<<8;
 78         case 9:  c += k[8];
 79         case 8:  b += (u32)k[7]<<24;
 80         case 7:  b += (u32)k[6]<<16;
 81         case 6:  b += (u32)k[5]<<8;
 82         case 5:  b += k[4];
 83         case 4:  a += (u32)k[3]<<24;
 84         case 3:  a += (u32)k[2]<<16;
 85         case 2:  a += (u32)k[1]<<8;
 86         case 1:  a += k[0];
 87                  __jhash_final(a, b, c);
 88         case 0: /* Nothing left to add */
 89                 break;
 90         }
 91 
 92         return c;
 93 }
 94 
 95 static inline u32 __jhash_nwords(u32 a, u32 b, u32 c, u32 initval)
 96 {
 97         a += initval;
 98         b += initval;
 99         c += initval;
100         __jhash_final(a, b, c);
101         return c;
102 }
103 
104 static inline u32 jhash_2words(u32 a, u32 b, u32 initval)
105 {
106         return __jhash_nwords(a, b, 0, initval + JHASH_INITVAL + (2 << 2));
107 }
108 
109 #define PCKT_FRAGMENTED 65343
110 #define IPV4_HDR_LEN_NO_OPT 20
111 #define IPV4_PLUS_ICMP_HDR 28
112 #define IPV6_PLUS_ICMP_HDR 48
113 #define RING_SIZE 2
114 #define MAX_VIPS 12
115 #define MAX_REALS 5
116 #define CTL_MAP_SIZE 16
117 #define CH_RINGS_SIZE (MAX_VIPS * RING_SIZE)
118 #define F_IPV6 (1 << 0)
119 #define F_HASH_NO_SRC_PORT (1 << 0)
120 #define F_ICMP (1 << 0)
121 #define F_SYN_SET (1 << 1)
122 
123 struct packet_description {
124         union {
125                 __be32 src;
126                 __be32 srcv6[4];
127         };
128         union {
129                 __be32 dst;
130                 __be32 dstv6[4];
131         };
132         union {
133                 __u32 ports;
134                 __u16 port16[2];
135         };
136         __u8 proto;
137         __u8 flags;
138 };
139 
140 struct ctl_value {
141         union {
142                 __u64 value;
143                 __u32 ifindex;
144                 __u8 mac[6];
145         };
146 };
147 
148 struct vip_meta {
149         __u32 flags;
150         __u32 vip_num;
151 };
152 
153 struct real_definition {
154         union {
155                 __be32 dst;
156                 __be32 dstv6[4];
157         };
158         __u8 flags;
159 };
160 
161 struct vip_stats {
162         __u64 bytes;
163         __u64 pkts;
164 };
165 
166 struct eth_hdr {
167         unsigned char eth_dest[ETH_ALEN];
168         unsigned char eth_source[ETH_ALEN];
169         unsigned short eth_proto;
170 };
171 
172 struct bpf_map_def SEC("maps") vip_map = {
173         .type = BPF_MAP_TYPE_HASH,
174         .key_size = sizeof(struct vip),
175         .value_size = sizeof(struct vip_meta),
176         .max_entries = MAX_VIPS,
177 };
178 
179 struct bpf_map_def SEC("maps") ch_rings = {
180         .type = BPF_MAP_TYPE_ARRAY,
181         .key_size = sizeof(__u32),
182         .value_size = sizeof(__u32),
183         .max_entries = CH_RINGS_SIZE,
184 };
185 
186 struct bpf_map_def SEC("maps") reals = {
187         .type = BPF_MAP_TYPE_ARRAY,
188         .key_size = sizeof(__u32),
189         .value_size = sizeof(struct real_definition),
190         .max_entries = MAX_REALS,
191 };
192 
193 struct bpf_map_def SEC("maps") stats = {
194         .type = BPF_MAP_TYPE_PERCPU_ARRAY,
195         .key_size = sizeof(__u32),
196         .value_size = sizeof(struct vip_stats),
197         .max_entries = MAX_VIPS,
198 };
199 
200 struct bpf_map_def SEC("maps") ctl_array = {
201         .type = BPF_MAP_TYPE_ARRAY,
202         .key_size = sizeof(__u32),
203         .value_size = sizeof(struct ctl_value),
204         .max_entries = CTL_MAP_SIZE,
205 };
206 
207 static __always_inline __u32 get_packet_hash(struct packet_description *pckt,
208                                              bool ipv6)
209 {
210         if (ipv6)
211                 return jhash_2words(jhash(pckt->srcv6, 16, MAX_VIPS),
212                                     pckt->ports, CH_RINGS_SIZE);
213         else
214                 return jhash_2words(pckt->src, pckt->ports, CH_RINGS_SIZE);
215 }
216 
217 static __always_inline bool get_packet_dst(struct real_definition **real,
218                                            struct packet_description *pckt,
219                                            struct vip_meta *vip_info,
220                                            bool is_ipv6)
221 {
222         __u32 hash = get_packet_hash(pckt, is_ipv6) % RING_SIZE;
223         __u32 key = RING_SIZE * vip_info->vip_num + hash;
224         __u32 *real_pos;
225 
226         real_pos = bpf_map_lookup_elem(&ch_rings, &key);
227         if (!real_pos)
228                 return false;
229         key = *real_pos;
230         *real = bpf_map_lookup_elem(&reals, &key);
231         if (!(*real))
232                 return false;
233         return true;
234 }
235 
236 static __always_inline int parse_icmpv6(void *data, void *data_end, __u64 off,
237                                         struct packet_description *pckt)
238 {
239         struct icmp6hdr *icmp_hdr;
240         struct ipv6hdr *ip6h;
241 
242         icmp_hdr = data + off;
243         if (icmp_hdr + 1 > data_end)
244                 return TC_ACT_SHOT;
245         if (icmp_hdr->icmp6_type != ICMPV6_PKT_TOOBIG)
246                 return TC_ACT_OK;
247         off += sizeof(struct icmp6hdr);
248         ip6h = data + off;
249         if (ip6h + 1 > data_end)
250                 return TC_ACT_SHOT;
251         pckt->proto = ip6h->nexthdr;
252         pckt->flags |= F_ICMP;
253         memcpy(pckt->srcv6, ip6h->daddr.s6_addr32, 16);
254         memcpy(pckt->dstv6, ip6h->saddr.s6_addr32, 16);
255         return TC_ACT_UNSPEC;
256 }
257 
258 static __always_inline int parse_icmp(void *data, void *data_end, __u64 off,
259                                       struct packet_description *pckt)
260 {
261         struct icmphdr *icmp_hdr;
262         struct iphdr *iph;
263 
264         icmp_hdr = data + off;
265         if (icmp_hdr + 1 > data_end)
266                 return TC_ACT_SHOT;
267         if (icmp_hdr->type != ICMP_DEST_UNREACH ||
268             icmp_hdr->code != ICMP_FRAG_NEEDED)
269                 return TC_ACT_OK;
270         off += sizeof(struct icmphdr);
271         iph = data + off;
272         if (iph + 1 > data_end)
273                 return TC_ACT_SHOT;
274         if (iph->ihl != 5)
275                 return TC_ACT_SHOT;
276         pckt->proto = iph->protocol;
277         pckt->flags |= F_ICMP;
278         pckt->src = iph->daddr;
279         pckt->dst = iph->saddr;
280         return TC_ACT_UNSPEC;
281 }
282 
283 static __always_inline bool parse_udp(void *data, __u64 off, void *data_end,
284                                       struct packet_description *pckt)
285 {
286         struct udphdr *udp;
287         udp = data + off;
288 
289         if (udp + 1 > data_end)
290                 return false;
291 
292         if (!(pckt->flags & F_ICMP)) {
293                 pckt->port16[0] = udp->source;
294                 pckt->port16[1] = udp->dest;
295         } else {
296                 pckt->port16[0] = udp->dest;
297                 pckt->port16[1] = udp->source;
298         }
299         return true;
300 }
301 
302 static __always_inline bool parse_tcp(void *data, __u64 off, void *data_end,
303                                       struct packet_description *pckt)
304 {
305         struct tcphdr *tcp;
306 
307         tcp = data + off;
308         if (tcp + 1 > data_end)
309                 return false;
310 
311         if (tcp->syn)
312                 pckt->flags |= F_SYN_SET;
313 
314         if (!(pckt->flags & F_ICMP)) {
315                 pckt->port16[0] = tcp->source;
316                 pckt->port16[1] = tcp->dest;
317         } else {
318                 pckt->port16[0] = tcp->dest;
319                 pckt->port16[1] = tcp->source;
320         }
321         return true;
322 }
323 
324 static __always_inline int process_packet(void *data, __u64 off, void *data_end,
325                                           bool is_ipv6, struct __sk_buff *skb)
326 {
327         void *pkt_start = (void *)(long)skb->data;
328         struct packet_description pckt = {};
329         struct eth_hdr *eth = pkt_start;
330         struct bpf_tunnel_key tkey = {};
331         struct vip_stats *data_stats;
332         struct real_definition *dst;
333         struct vip_meta *vip_info;
334         struct ctl_value *cval;
335         __u32 v4_intf_pos = 1;
336         __u32 v6_intf_pos = 2;
337         struct ipv6hdr *ip6h;
338         struct vip vip = {};
339         struct iphdr *iph;
340         int tun_flag = 0;
341         __u16 pkt_bytes;
342         __u64 iph_len;
343         __u32 ifindex;
344         __u8 protocol;
345         __u32 vip_num;
346         int action;
347 
348         tkey.tunnel_ttl = 64;
349         if (is_ipv6) {
350                 ip6h = data + off;
351                 if (ip6h + 1 > data_end)
352                         return TC_ACT_SHOT;
353 
354                 iph_len = sizeof(struct ipv6hdr);
355                 protocol = ip6h->nexthdr;
356                 pckt.proto = protocol;
357                 pkt_bytes = bpf_ntohs(ip6h->payload_len);
358                 off += iph_len;
359                 if (protocol == IPPROTO_FRAGMENT) {
360                         return TC_ACT_SHOT;
361                 } else if (protocol == IPPROTO_ICMPV6) {
362                         action = parse_icmpv6(data, data_end, off, &pckt);
363                         if (action >= 0)
364                                 return action;
365                         off += IPV6_PLUS_ICMP_HDR;
366                 } else {
367                         memcpy(pckt.srcv6, ip6h->saddr.s6_addr32, 16);
368                         memcpy(pckt.dstv6, ip6h->daddr.s6_addr32, 16);
369                 }
370         } else {
371                 iph = data + off;
372                 if (iph + 1 > data_end)
373                         return TC_ACT_SHOT;
374                 if (iph->ihl != 5)
375                         return TC_ACT_SHOT;
376 
377                 protocol = iph->protocol;
378                 pckt.proto = protocol;
379                 pkt_bytes = bpf_ntohs(iph->tot_len);
380                 off += IPV4_HDR_LEN_NO_OPT;
381 
382                 if (iph->frag_off & PCKT_FRAGMENTED)
383                         return TC_ACT_SHOT;
384                 if (protocol == IPPROTO_ICMP) {
385                         action = parse_icmp(data, data_end, off, &pckt);
386                         if (action >= 0)
387                                 return action;
388                         off += IPV4_PLUS_ICMP_HDR;
389                 } else {
390                         pckt.src = iph->saddr;
391                         pckt.dst = iph->daddr;
392                 }
393         }
394         protocol = pckt.proto;
395 
396         if (protocol == IPPROTO_TCP) {
397                 if (!parse_tcp(data, off, data_end, &pckt))
398                         return TC_ACT_SHOT;
399         } else if (protocol == IPPROTO_UDP) {
400                 if (!parse_udp(data, off, data_end, &pckt))
401                         return TC_ACT_SHOT;
402         } else {
403                 return TC_ACT_SHOT;
404         }
405 
406         if (is_ipv6)
407                 memcpy(vip.daddr.v6, pckt.dstv6, 16);
408         else
409                 vip.daddr.v4 = pckt.dst;
410 
411         vip.dport = pckt.port16[1];
412         vip.protocol = pckt.proto;
413         vip_info = bpf_map_lookup_elem(&vip_map, &vip);
414         if (!vip_info) {
415                 vip.dport = 0;
416                 vip_info = bpf_map_lookup_elem(&vip_map, &vip);
417                 if (!vip_info)
418                         return TC_ACT_SHOT;
419                 pckt.port16[1] = 0;
420         }
421 
422         if (vip_info->flags & F_HASH_NO_SRC_PORT)
423                 pckt.port16[0] = 0;
424 
425         if (!get_packet_dst(&dst, &pckt, vip_info, is_ipv6))
426                 return TC_ACT_SHOT;
427 
428         if (dst->flags & F_IPV6) {
429                 cval = bpf_map_lookup_elem(&ctl_array, &v6_intf_pos);
430                 if (!cval)
431                         return TC_ACT_SHOT;
432                 ifindex = cval->ifindex;
433                 memcpy(tkey.remote_ipv6, dst->dstv6, 16);
434                 tun_flag = BPF_F_TUNINFO_IPV6;
435         } else {
436                 cval = bpf_map_lookup_elem(&ctl_array, &v4_intf_pos);
437                 if (!cval)
438                         return TC_ACT_SHOT;
439                 ifindex = cval->ifindex;
440                 tkey.remote_ipv4 = dst->dst;
441         }
442         vip_num = vip_info->vip_num;
443         data_stats = bpf_map_lookup_elem(&stats, &vip_num);
444         if (!data_stats)
445                 return TC_ACT_SHOT;
446         data_stats->pkts++;
447         data_stats->bytes += pkt_bytes;
448         bpf_skb_set_tunnel_key(skb, &tkey, sizeof(tkey), tun_flag);
449         *(u32 *)eth->eth_dest = tkey.remote_ipv4;
450         return bpf_redirect(ifindex, 0);
451 }
452 
453 SEC("l4lb-demo")
454 int balancer_ingress(struct __sk_buff *ctx)
455 {
456         void *data_end = (void *)(long)ctx->data_end;
457         void *data = (void *)(long)ctx->data;
458         struct eth_hdr *eth = data;
459         __u32 eth_proto;
460         __u32 nh_off;
461 
462         nh_off = sizeof(struct eth_hdr);
463         if (data + nh_off > data_end)
464                 return TC_ACT_SHOT;
465         eth_proto = eth->eth_proto;
466         if (eth_proto == bpf_htons(ETH_P_IP))
467                 return process_packet(data, nh_off, data_end, false, ctx);
468         else if (eth_proto == bpf_htons(ETH_P_IPV6))
469                 return process_packet(data, nh_off, data_end, true, ctx);
470         else
471                 return TC_ACT_SHOT;
472 }
473 char _license[] SEC("license") = "GPL";
474 

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