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  1// SPDX-License-Identifier: GPL-2.0
  2// Copyright (c) 2017 Facebook
  3#include <stddef.h>
  4#include <stdbool.h>
  5#include <string.h>
  6#include <linux/pkt_cls.h>
  7#include <linux/bpf.h>
  8#include <linux/in.h>
  9#include <linux/if_ether.h>
 10#include <linux/ip.h>
 11#include <linux/ipv6.h>
 12#include <linux/icmp.h>
 13#include <linux/icmpv6.h>
 14#include <linux/tcp.h>
 15#include <linux/udp.h>
 16#include <bpf/bpf_helpers.h>
 17#include <bpf/bpf_endian.h>
 18
 19static __always_inline __u32 rol32(__u32 word, unsigned int shift)
 20{
 21	return (word << shift) | (word >> ((-shift) & 31));
 22}
 23
 24/* copy paste of jhash from kernel sources to make sure llvm
 25 * can compile it into valid sequence of bpf instructions
 26 */
 27#define __jhash_mix(a, b, c)			\
 28{						\
 29	a -= c;  a ^= rol32(c, 4);  c += b;	\
 30	b -= a;  b ^= rol32(a, 6);  a += c;	\
 31	c -= b;  c ^= rol32(b, 8);  b += a;	\
 32	a -= c;  a ^= rol32(c, 16); c += b;	\
 33	b -= a;  b ^= rol32(a, 19); a += c;	\
 34	c -= b;  c ^= rol32(b, 4);  b += a;	\
 35}
 36
 37#define __jhash_final(a, b, c)			\
 38{						\
 39	c ^= b; c -= rol32(b, 14);		\
 40	a ^= c; a -= rol32(c, 11);		\
 41	b ^= a; b -= rol32(a, 25);		\
 42	c ^= b; c -= rol32(b, 16);		\
 43	a ^= c; a -= rol32(c, 4);		\
 44	b ^= a; b -= rol32(a, 14);		\
 45	c ^= b; c -= rol32(b, 24);		\
 46}
 47
 48#define JHASH_INITVAL		0xdeadbeef
 49
 50typedef unsigned int u32;
 51
 52static __noinline
 53u32 jhash(const void *key, u32 length, u32 initval)
 54{
 55	u32 a, b, c;
 56	const unsigned char *k = key;
 57
 58	a = b = c = JHASH_INITVAL + length + initval;
 59
 60	while (length > 12) {
 61		a += *(u32 *)(k);
 62		b += *(u32 *)(k + 4);
 63		c += *(u32 *)(k + 8);
 64		__jhash_mix(a, b, c);
 65		length -= 12;
 66		k += 12;
 67	}
 68	switch (length) {
 69	case 12: c += (u32)k[11]<<24;
 70	case 11: c += (u32)k[10]<<16;
 71	case 10: c += (u32)k[9]<<8;
 72	case 9:  c += k[8];
 73	case 8:  b += (u32)k[7]<<24;
 74	case 7:  b += (u32)k[6]<<16;
 75	case 6:  b += (u32)k[5]<<8;
 76	case 5:  b += k[4];
 77	case 4:  a += (u32)k[3]<<24;
 78	case 3:  a += (u32)k[2]<<16;
 79	case 2:  a += (u32)k[1]<<8;
 80	case 1:  a += k[0];
 81		 __jhash_final(a, b, c);
 82	case 0: /* Nothing left to add */
 83		break;
 84	}
 85
 86	return c;
 87}
 88
 89__noinline
 90u32 __jhash_nwords(u32 a, u32 b, u32 c, u32 initval)
 91{
 92	a += initval;
 93	b += initval;
 94	c += initval;
 95	__jhash_final(a, b, c);
 96	return c;
 97}
 98
 99__noinline
100u32 jhash_2words(u32 a, u32 b, u32 initval)
101{
102	return __jhash_nwords(a, b, 0, initval + JHASH_INITVAL + (2 << 2));
103}
104
105struct flow_key {
106	union {
107		__be32 src;
108		__be32 srcv6[4];
109	};
110	union {
111		__be32 dst;
112		__be32 dstv6[4];
113	};
114	union {
115		__u32 ports;
116		__u16 port16[2];
117	};
118	__u8 proto;
119};
120
121struct packet_description {
122	struct flow_key flow;
123	__u8 flags;
124};
125
126struct ctl_value {
127	union {
128		__u64 value;
129		__u32 ifindex;
130		__u8 mac[6];
131	};
132};
133
134struct vip_definition {
135	union {
136		__be32 vip;
137		__be32 vipv6[4];
138	};
139	__u16 port;
140	__u16 family;
141	__u8 proto;
142};
143
144struct vip_meta {
145	__u32 flags;
146	__u32 vip_num;
147};
148
149struct real_pos_lru {
150	__u32 pos;
151	__u64 atime;
152};
153
154struct real_definition {
155	union {
156		__be32 dst;
157		__be32 dstv6[4];
158	};
159	__u8 flags;
160};
161
162struct lb_stats {
163	__u64 v2;
164	__u64 v1;
165};
166
167struct {
168	__uint(type, BPF_MAP_TYPE_HASH);
169	__uint(max_entries, 512);
170	__type(key, struct vip_definition);
171	__type(value, struct vip_meta);
172} vip_map SEC(".maps");
173
174struct {
175	__uint(type, BPF_MAP_TYPE_LRU_HASH);
176	__uint(max_entries, 300);
177	__uint(map_flags, 1U << 1);
178	__type(key, struct flow_key);
179	__type(value, struct real_pos_lru);
180} lru_cache SEC(".maps");
181
182struct {
183	__uint(type, BPF_MAP_TYPE_ARRAY);
184	__uint(max_entries, 12 * 655);
185	__type(key, __u32);
186	__type(value, __u32);
187} ch_rings SEC(".maps");
188
189struct {
190	__uint(type, BPF_MAP_TYPE_ARRAY);
191	__uint(max_entries, 40);
192	__type(key, __u32);
193	__type(value, struct real_definition);
194} reals SEC(".maps");
195
196struct {
197	__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
198	__uint(max_entries, 515);
199	__type(key, __u32);
200	__type(value, struct lb_stats);
201} stats SEC(".maps");
202
203struct {
204	__uint(type, BPF_MAP_TYPE_ARRAY);
205	__uint(max_entries, 16);
206	__type(key, __u32);
207	__type(value, struct ctl_value);
208} ctl_array SEC(".maps");
209
210struct eth_hdr {
211	unsigned char eth_dest[6];
212	unsigned char eth_source[6];
213	unsigned short eth_proto;
214};
215
216static __noinline __u64 calc_offset(bool is_ipv6, bool is_icmp)
217{
218	__u64 off = sizeof(struct eth_hdr);
219	if (is_ipv6) {
220		off += sizeof(struct ipv6hdr);
221		if (is_icmp)
222			off += sizeof(struct icmp6hdr) + sizeof(struct ipv6hdr);
223	} else {
224		off += sizeof(struct iphdr);
225		if (is_icmp)
226			off += sizeof(struct icmphdr) + sizeof(struct iphdr);
227	}
228	return off;
229}
230
231static __attribute__ ((noinline))
232bool parse_udp(void *data, void *data_end,
233	       bool is_ipv6, struct packet_description *pckt)
234{
235
236	bool is_icmp = !((pckt->flags & (1 << 0)) == 0);
237	__u64 off = calc_offset(is_ipv6, is_icmp);
238	struct udphdr *udp;
239	udp = data + off;
240
241	if (udp + 1 > data_end)
242		return false;
243	if (!is_icmp) {
244		pckt->flow.port16[0] = udp->source;
245		pckt->flow.port16[1] = udp->dest;
246	} else {
247		pckt->flow.port16[0] = udp->dest;
248		pckt->flow.port16[1] = udp->source;
249	}
250	return true;
251}
252
253static __attribute__ ((noinline))
254bool parse_tcp(void *data, void *data_end,
255	       bool is_ipv6, struct packet_description *pckt)
256{
257
258	bool is_icmp = !((pckt->flags & (1 << 0)) == 0);
259	__u64 off = calc_offset(is_ipv6, is_icmp);
260	struct tcphdr *tcp;
261
262	tcp = data + off;
263	if (tcp + 1 > data_end)
264		return false;
265	if (tcp->syn)
266		pckt->flags |= (1 << 1);
267	if (!is_icmp) {
268		pckt->flow.port16[0] = tcp->source;
269		pckt->flow.port16[1] = tcp->dest;
270	} else {
271		pckt->flow.port16[0] = tcp->dest;
272		pckt->flow.port16[1] = tcp->source;
273	}
274	return true;
275}
276
277static __attribute__ ((noinline))
278bool encap_v6(struct xdp_md *xdp, struct ctl_value *cval,
279	      struct packet_description *pckt,
280	      struct real_definition *dst, __u32 pkt_bytes)
281{
282	struct eth_hdr *new_eth;
283	struct eth_hdr *old_eth;
284	struct ipv6hdr *ip6h;
285	__u32 ip_suffix;
286	void *data_end;
287	void *data;
288
289	if (bpf_xdp_adjust_head(xdp, 0 - (int)sizeof(struct ipv6hdr)))
290		return false;
291	data = (void *)(long)xdp->data;
292	data_end = (void *)(long)xdp->data_end;
293	new_eth = data;
294	ip6h = data + sizeof(struct eth_hdr);
295	old_eth = data + sizeof(struct ipv6hdr);
296	if (new_eth + 1 > data_end ||
297	    old_eth + 1 > data_end || ip6h + 1 > data_end)
298		return false;
299	memcpy(new_eth->eth_dest, cval->mac, 6);
300	memcpy(new_eth->eth_source, old_eth->eth_dest, 6);
301	new_eth->eth_proto = 56710;
302	ip6h->version = 6;
303	ip6h->priority = 0;
304	memset(ip6h->flow_lbl, 0, sizeof(ip6h->flow_lbl));
305
306	ip6h->nexthdr = IPPROTO_IPV6;
307	ip_suffix = pckt->flow.srcv6[3] ^ pckt->flow.port16[0];
308	ip6h->payload_len =
309	    bpf_htons(pkt_bytes + sizeof(struct ipv6hdr));
310	ip6h->hop_limit = 4;
311
312	ip6h->saddr.in6_u.u6_addr32[0] = 1;
313	ip6h->saddr.in6_u.u6_addr32[1] = 2;
314	ip6h->saddr.in6_u.u6_addr32[2] = 3;
315	ip6h->saddr.in6_u.u6_addr32[3] = ip_suffix;
316	memcpy(ip6h->daddr.in6_u.u6_addr32, dst->dstv6, 16);
317	return true;
318}
319
320static __attribute__ ((noinline))
321bool encap_v4(struct xdp_md *xdp, struct ctl_value *cval,
322	      struct packet_description *pckt,
323	      struct real_definition *dst, __u32 pkt_bytes)
324{
325
326	__u32 ip_suffix = bpf_ntohs(pckt->flow.port16[0]);
327	struct eth_hdr *new_eth;
328	struct eth_hdr *old_eth;
329	__u16 *next_iph_u16;
330	struct iphdr *iph;
331	__u32 csum = 0;
332	void *data_end;
333	void *data;
334
335	ip_suffix <<= 15;
336	ip_suffix ^= pckt->flow.src;
337	if (bpf_xdp_adjust_head(xdp, 0 - (int)sizeof(struct iphdr)))
338		return false;
339	data = (void *)(long)xdp->data;
340	data_end = (void *)(long)xdp->data_end;
341	new_eth = data;
342	iph = data + sizeof(struct eth_hdr);
343	old_eth = data + sizeof(struct iphdr);
344	if (new_eth + 1 > data_end ||
345	    old_eth + 1 > data_end || iph + 1 > data_end)
346		return false;
347	memcpy(new_eth->eth_dest, cval->mac, 6);
348	memcpy(new_eth->eth_source, old_eth->eth_dest, 6);
349	new_eth->eth_proto = 8;
350	iph->version = 4;
351	iph->ihl = 5;
352	iph->frag_off = 0;
353	iph->protocol = IPPROTO_IPIP;
354	iph->check = 0;
355	iph->tos = 1;
356	iph->tot_len = bpf_htons(pkt_bytes + sizeof(struct iphdr));
357	/* don't update iph->daddr, since it will overwrite old eth_proto
358	 * and multiple iterations of bpf_prog_run() will fail
359	 */
360
361	iph->saddr = ((0xFFFF0000 & ip_suffix) | 4268) ^ dst->dst;
362	iph->ttl = 4;
363
364	next_iph_u16 = (__u16 *) iph;
365#pragma clang loop unroll(full)
366	for (int i = 0; i < sizeof(struct iphdr) >> 1; i++)
367		csum += *next_iph_u16++;
368	iph->check = ~((csum & 0xffff) + (csum >> 16));
369	if (bpf_xdp_adjust_head(xdp, (int)sizeof(struct iphdr)))
370		return false;
371	return true;
372}
373
374static __attribute__ ((noinline))
375int swap_mac_and_send(void *data, void *data_end)
376{
377	unsigned char tmp_mac[6];
378	struct eth_hdr *eth;
379
380	eth = data;
381	memcpy(tmp_mac, eth->eth_source, 6);
382	memcpy(eth->eth_source, eth->eth_dest, 6);
383	memcpy(eth->eth_dest, tmp_mac, 6);
384	return XDP_TX;
385}
386
387static __attribute__ ((noinline))
388int send_icmp_reply(void *data, void *data_end)
389{
390	struct icmphdr *icmp_hdr;
391	__u16 *next_iph_u16;
392	__u32 tmp_addr = 0;
393	struct iphdr *iph;
394	__u32 csum = 0;
395	__u64 off = 0;
396
397	if (data + sizeof(struct eth_hdr)
398	     + sizeof(struct iphdr) + sizeof(struct icmphdr) > data_end)
399		return XDP_DROP;
400	off += sizeof(struct eth_hdr);
401	iph = data + off;
402	off += sizeof(struct iphdr);
403	icmp_hdr = data + off;
404	icmp_hdr->type = 0;
405	icmp_hdr->checksum += 0x0007;
406	iph->ttl = 4;
407	tmp_addr = iph->daddr;
408	iph->daddr = iph->saddr;
409	iph->saddr = tmp_addr;
410	iph->check = 0;
411	next_iph_u16 = (__u16 *) iph;
412#pragma clang loop unroll(full)
413	for (int i = 0; i < sizeof(struct iphdr) >> 1; i++)
414		csum += *next_iph_u16++;
415	iph->check = ~((csum & 0xffff) + (csum >> 16));
416	return swap_mac_and_send(data, data_end);
417}
418
419static __attribute__ ((noinline))
420int send_icmp6_reply(void *data, void *data_end)
421{
422	struct icmp6hdr *icmp_hdr;
423	struct ipv6hdr *ip6h;
424	__be32 tmp_addr[4];
425	__u64 off = 0;
426
427	if (data + sizeof(struct eth_hdr)
428	     + sizeof(struct ipv6hdr) + sizeof(struct icmp6hdr) > data_end)
429		return XDP_DROP;
430	off += sizeof(struct eth_hdr);
431	ip6h = data + off;
432	off += sizeof(struct ipv6hdr);
433	icmp_hdr = data + off;
434	icmp_hdr->icmp6_type = 129;
435	icmp_hdr->icmp6_cksum -= 0x0001;
436	ip6h->hop_limit = 4;
437	memcpy(tmp_addr, ip6h->saddr.in6_u.u6_addr32, 16);
438	memcpy(ip6h->saddr.in6_u.u6_addr32, ip6h->daddr.in6_u.u6_addr32, 16);
439	memcpy(ip6h->daddr.in6_u.u6_addr32, tmp_addr, 16);
440	return swap_mac_and_send(data, data_end);
441}
442
443static __attribute__ ((noinline))
444int parse_icmpv6(void *data, void *data_end, __u64 off,
445		 struct packet_description *pckt)
446{
447	struct icmp6hdr *icmp_hdr;
448	struct ipv6hdr *ip6h;
449
450	icmp_hdr = data + off;
451	if (icmp_hdr + 1 > data_end)
452		return XDP_DROP;
453	if (icmp_hdr->icmp6_type == 128)
454		return send_icmp6_reply(data, data_end);
455	if (icmp_hdr->icmp6_type != 3)
456		return XDP_PASS;
457	off += sizeof(struct icmp6hdr);
458	ip6h = data + off;
459	if (ip6h + 1 > data_end)
460		return XDP_DROP;
461	pckt->flow.proto = ip6h->nexthdr;
462	pckt->flags |= (1 << 0);
463	memcpy(pckt->flow.srcv6, ip6h->daddr.in6_u.u6_addr32, 16);
464	memcpy(pckt->flow.dstv6, ip6h->saddr.in6_u.u6_addr32, 16);
465	return -1;
466}
467
468static __attribute__ ((noinline))
469int parse_icmp(void *data, void *data_end, __u64 off,
470	       struct packet_description *pckt)
471{
472	struct icmphdr *icmp_hdr;
473	struct iphdr *iph;
474
475	icmp_hdr = data + off;
476	if (icmp_hdr + 1 > data_end)
477		return XDP_DROP;
478	if (icmp_hdr->type == 8)
479		return send_icmp_reply(data, data_end);
480	if ((icmp_hdr->type != 3) || (icmp_hdr->code != 4))
481		return XDP_PASS;
482	off += sizeof(struct icmphdr);
483	iph = data + off;
484	if (iph + 1 > data_end)
485		return XDP_DROP;
486	if (iph->ihl != 5)
487		return XDP_DROP;
488	pckt->flow.proto = iph->protocol;
489	pckt->flags |= (1 << 0);
490	pckt->flow.src = iph->daddr;
491	pckt->flow.dst = iph->saddr;
492	return -1;
493}
494
495static __attribute__ ((noinline))
496__u32 get_packet_hash(struct packet_description *pckt,
497		      bool hash_16bytes)
498{
499	if (hash_16bytes)
500		return jhash_2words(jhash(pckt->flow.srcv6, 16, 12),
501				    pckt->flow.ports, 24);
502	else
503		return jhash_2words(pckt->flow.src, pckt->flow.ports,
504				    24);
505}
506
507__attribute__ ((noinline))
508static bool get_packet_dst(struct real_definition **real,
509			   struct packet_description *pckt,
510			   struct vip_meta *vip_info,
511			   bool is_ipv6, void *lru_map)
512{
513	struct real_pos_lru new_dst_lru = { };
514	bool hash_16bytes = is_ipv6;
515	__u32 *real_pos, hash, key;
516	__u64 cur_time;
517
518	if (vip_info->flags & (1 << 2))
519		hash_16bytes = 1;
520	if (vip_info->flags & (1 << 3)) {
521		pckt->flow.port16[0] = pckt->flow.port16[1];
522		memset(pckt->flow.srcv6, 0, 16);
523	}
524	hash = get_packet_hash(pckt, hash_16bytes);
525	if (hash != 0x358459b7 /* jhash of ipv4 packet */  &&
526	    hash != 0x2f4bc6bb /* jhash of ipv6 packet */)
527		return false;
528	key = 2 * vip_info->vip_num + hash % 2;
529	real_pos = bpf_map_lookup_elem(&ch_rings, &key);
530	if (!real_pos)
531		return false;
532	key = *real_pos;
533	*real = bpf_map_lookup_elem(&reals, &key);
534	if (!(*real))
535		return false;
536	if (!(vip_info->flags & (1 << 1))) {
537		__u32 conn_rate_key = 512 + 2;
538		struct lb_stats *conn_rate_stats =
539		    bpf_map_lookup_elem(&stats, &conn_rate_key);
540
541		if (!conn_rate_stats)
542			return true;
543		cur_time = bpf_ktime_get_ns();
544		if ((cur_time - conn_rate_stats->v2) >> 32 > 0xffFFFF) {
545			conn_rate_stats->v1 = 1;
546			conn_rate_stats->v2 = cur_time;
547		} else {
548			conn_rate_stats->v1 += 1;
549			if (conn_rate_stats->v1 >= 1)
550				return true;
551		}
552		if (pckt->flow.proto == IPPROTO_UDP)
553			new_dst_lru.atime = cur_time;
554		new_dst_lru.pos = key;
555		bpf_map_update_elem(lru_map, &pckt->flow, &new_dst_lru, 0);
556	}
557	return true;
558}
559
560__attribute__ ((noinline))
561static void connection_table_lookup(struct real_definition **real,
562				    struct packet_description *pckt,
563				    void *lru_map)
564{
565
566	struct real_pos_lru *dst_lru;
567	__u64 cur_time;
568	__u32 key;
569
570	dst_lru = bpf_map_lookup_elem(lru_map, &pckt->flow);
571	if (!dst_lru)
572		return;
573	if (pckt->flow.proto == IPPROTO_UDP) {
574		cur_time = bpf_ktime_get_ns();
575		if (cur_time - dst_lru->atime > 300000)
576			return;
577		dst_lru->atime = cur_time;
578	}
579	key = dst_lru->pos;
580	*real = bpf_map_lookup_elem(&reals, &key);
581}
582
583/* don't believe your eyes!
584 * below function has 6 arguments whereas bpf and llvm allow maximum of 5
585 * but since it's _static_ llvm can optimize one argument away
586 */
587__attribute__ ((noinline))
588static int process_l3_headers_v6(struct packet_description *pckt,
589				 __u8 *protocol, __u64 off,
590				 __u16 *pkt_bytes, void *data,
591				 void *data_end)
592{
593	struct ipv6hdr *ip6h;
594	__u64 iph_len;
595	int action;
596
597	ip6h = data + off;
598	if (ip6h + 1 > data_end)
599		return XDP_DROP;
600	iph_len = sizeof(struct ipv6hdr);
601	*protocol = ip6h->nexthdr;
602	pckt->flow.proto = *protocol;
603	*pkt_bytes = bpf_ntohs(ip6h->payload_len);
604	off += iph_len;
605	if (*protocol == 45) {
606		return XDP_DROP;
607	} else if (*protocol == 59) {
608		action = parse_icmpv6(data, data_end, off, pckt);
609		if (action >= 0)
610			return action;
611	} else {
612		memcpy(pckt->flow.srcv6, ip6h->saddr.in6_u.u6_addr32, 16);
613		memcpy(pckt->flow.dstv6, ip6h->daddr.in6_u.u6_addr32, 16);
614	}
615	return -1;
616}
617
618__attribute__ ((noinline))
619static int process_l3_headers_v4(struct packet_description *pckt,
620				 __u8 *protocol, __u64 off,
621				 __u16 *pkt_bytes, void *data,
622				 void *data_end)
623{
624	struct iphdr *iph;
625	int action;
626
627	iph = data + off;
628	if (iph + 1 > data_end)
629		return XDP_DROP;
630	if (iph->ihl != 5)
631		return XDP_DROP;
632	*protocol = iph->protocol;
633	pckt->flow.proto = *protocol;
634	*pkt_bytes = bpf_ntohs(iph->tot_len);
635	off += 20;
636	if (iph->frag_off & 65343)
637		return XDP_DROP;
638	if (*protocol == IPPROTO_ICMP) {
639		action = parse_icmp(data, data_end, off, pckt);
640		if (action >= 0)
641			return action;
642	} else {
643		pckt->flow.src = iph->saddr;
644		pckt->flow.dst = iph->daddr;
645	}
646	return -1;
647}
648
649__attribute__ ((noinline))
650static int process_packet(void *data, __u64 off, void *data_end,
651			  bool is_ipv6, struct xdp_md *xdp)
652{
653
654	struct real_definition *dst = NULL;
655	struct packet_description pckt = { };
656	struct vip_definition vip = { };
657	struct lb_stats *data_stats;
658	void *lru_map = &lru_cache;
659	struct vip_meta *vip_info;
660	__u32 lru_stats_key = 513;
661	__u32 mac_addr_pos = 0;
662	__u32 stats_key = 512;
663	struct ctl_value *cval;
664	__u16 pkt_bytes;
665	__u8 protocol;
666	__u32 vip_num;
667	int action;
668
669	if (is_ipv6)
670		action = process_l3_headers_v6(&pckt, &protocol, off,
671					       &pkt_bytes, data, data_end);
672	else
673		action = process_l3_headers_v4(&pckt, &protocol, off,
674					       &pkt_bytes, data, data_end);
675	if (action >= 0)
676		return action;
677	protocol = pckt.flow.proto;
678	if (protocol == IPPROTO_TCP) {
679		if (!parse_tcp(data, data_end, is_ipv6, &pckt))
680			return XDP_DROP;
681	} else if (protocol == IPPROTO_UDP) {
682		if (!parse_udp(data, data_end, is_ipv6, &pckt))
683			return XDP_DROP;
684	} else {
685		return XDP_TX;
686	}
687
688	if (is_ipv6)
689		memcpy(vip.vipv6, pckt.flow.dstv6, 16);
690	else
691		vip.vip = pckt.flow.dst;
692	vip.port = pckt.flow.port16[1];
693	vip.proto = pckt.flow.proto;
694	vip_info = bpf_map_lookup_elem(&vip_map, &vip);
695	if (!vip_info) {
696		vip.port = 0;
697		vip_info = bpf_map_lookup_elem(&vip_map, &vip);
698		if (!vip_info)
699			return XDP_PASS;
700		if (!(vip_info->flags & (1 << 4)))
701			pckt.flow.port16[1] = 0;
702	}
703	if (data_end - data > 1400)
704		return XDP_DROP;
705	data_stats = bpf_map_lookup_elem(&stats, &stats_key);
706	if (!data_stats)
707		return XDP_DROP;
708	data_stats->v1 += 1;
709	if (!dst) {
710		if (vip_info->flags & (1 << 0))
711			pckt.flow.port16[0] = 0;
712		if (!(pckt.flags & (1 << 1)) && !(vip_info->flags & (1 << 1)))
713			connection_table_lookup(&dst, &pckt, lru_map);
714		if (dst)
715			goto out;
716		if (pckt.flow.proto == IPPROTO_TCP) {
717			struct lb_stats *lru_stats =
718			    bpf_map_lookup_elem(&stats, &lru_stats_key);
719
720			if (!lru_stats)
721				return XDP_DROP;
722			if (pckt.flags & (1 << 1))
723				lru_stats->v1 += 1;
724			else
725				lru_stats->v2 += 1;
726		}
727		if (!get_packet_dst(&dst, &pckt, vip_info, is_ipv6, lru_map))
728			return XDP_DROP;
729		data_stats->v2 += 1;
730	}
731out:
732	cval = bpf_map_lookup_elem(&ctl_array, &mac_addr_pos);
733	if (!cval)
734		return XDP_DROP;
735	if (dst->flags & (1 << 0)) {
736		if (!encap_v6(xdp, cval, &pckt, dst, pkt_bytes))
737			return XDP_DROP;
738	} else {
739		if (!encap_v4(xdp, cval, &pckt, dst, pkt_bytes))
740			return XDP_DROP;
741	}
742	vip_num = vip_info->vip_num;
743	data_stats = bpf_map_lookup_elem(&stats, &vip_num);
744	if (!data_stats)
745		return XDP_DROP;
746	data_stats->v1 += 1;
747	data_stats->v2 += pkt_bytes;
748
749	data = (void *)(long)xdp->data;
750	data_end = (void *)(long)xdp->data_end;
751	if (data + 4 > data_end)
752		return XDP_DROP;
753	*(u32 *)data = dst->dst;
754	return XDP_DROP;
755}
756
757SEC("xdp")
758int balancer_ingress_v4(struct xdp_md *ctx)
759{
760	void *data = (void *)(long)ctx->data;
761	void *data_end = (void *)(long)ctx->data_end;
762	struct eth_hdr *eth = data;
763	__u32 eth_proto;
764	__u32 nh_off;
765
766	nh_off = sizeof(struct eth_hdr);
767	if (data + nh_off > data_end)
768		return XDP_DROP;
769	eth_proto = bpf_ntohs(eth->eth_proto);
770	if (eth_proto == ETH_P_IP)
771		return process_packet(data, nh_off, data_end, 0, ctx);
772	else
773		return XDP_DROP;
774}
775
776SEC("xdp")
777int balancer_ingress_v6(struct xdp_md *ctx)
778{
779	void *data = (void *)(long)ctx->data;
780	void *data_end = (void *)(long)ctx->data_end;
781	struct eth_hdr *eth = data;
782	__u32 eth_proto;
783	__u32 nh_off;
784
785	nh_off = sizeof(struct eth_hdr);
786	if (data + nh_off > data_end)
787		return XDP_DROP;
788	eth_proto = bpf_ntohs(eth->eth_proto);
789	if (eth_proto == ETH_P_IPV6)
790		return process_packet(data, nh_off, data_end, 1, ctx);
791	else
792		return XDP_DROP;
793}
794
795char _license[] SEC("license") = "GPL";