xref: /dpdk/lib/net/rte_ip.h (revision 03ab51eafda992874a48c392ca66ffb577fe2b71)
1 /* SPDX-License-Identifier: BSD-3-Clause
2  * Copyright(c) 1982, 1986, 1990, 1993
3  *      The Regents of the University of California.
4  * Copyright(c) 2010-2014 Intel Corporation.
5  * Copyright(c) 2014 6WIND S.A.
6  * All rights reserved.
7  */
8 
9 #ifndef _RTE_IP_H_
10 #define _RTE_IP_H_
11 
12 /**
13  * @file
14  *
15  * IP-related defines
16  */
17 
18 #include <stdint.h>
19 
20 #ifdef RTE_EXEC_ENV_WINDOWS
21 #include <ws2tcpip.h>
22 #else
23 #include <sys/socket.h>
24 #include <sys/types.h>
25 #include <netinet/in.h>
26 #include <arpa/inet.h>
27 #include <netinet/ip.h>
28 #include <netinet/ip6.h>
29 #endif
30 
31 #include <rte_byteorder.h>
32 #include <rte_mbuf.h>
33 
34 #ifdef __cplusplus
35 extern "C" {
36 #endif
37 
38 /**
39  * IPv4 Header
40  */
41 struct rte_ipv4_hdr {
42 	uint8_t  version_ihl;		/**< version and header length */
43 	uint8_t  type_of_service;	/**< type of service */
44 	rte_be16_t total_length;	/**< length of packet */
45 	rte_be16_t packet_id;		/**< packet ID */
46 	rte_be16_t fragment_offset;	/**< fragmentation offset */
47 	uint8_t  time_to_live;		/**< time to live */
48 	uint8_t  next_proto_id;		/**< protocol ID */
49 	rte_be16_t hdr_checksum;	/**< header checksum */
50 	rte_be32_t src_addr;		/**< source address */
51 	rte_be32_t dst_addr;		/**< destination address */
52 } __rte_packed;
53 
54 /** Create IPv4 address */
55 #define RTE_IPV4(a, b, c, d) ((uint32_t)(((a) & 0xff) << 24) | \
56 					   (((b) & 0xff) << 16) | \
57 					   (((c) & 0xff) << 8)  | \
58 					   ((d) & 0xff))
59 
60 /** Maximal IPv4 packet length (including a header) */
61 #define RTE_IPV4_MAX_PKT_LEN        65535
62 
63 /** Internet header length mask for version_ihl field */
64 #define RTE_IPV4_HDR_IHL_MASK	(0x0f)
65 /**
66  * Internet header length field multiplier (IHL field specifies overall header
67  * length in number of 4-byte words)
68  */
69 #define RTE_IPV4_IHL_MULTIPLIER	(4)
70 
71 /* Type of Service fields */
72 #define RTE_IPV4_HDR_DSCP_MASK	(0xfc)
73 #define RTE_IPV4_HDR_ECN_MASK	(0x03)
74 #define RTE_IPV4_HDR_ECN_CE	RTE_IPV4_HDR_ECN_MASK
75 
76 /* Fragment Offset * Flags. */
77 #define	RTE_IPV4_HDR_DF_SHIFT	14
78 #define	RTE_IPV4_HDR_MF_SHIFT	13
79 #define	RTE_IPV4_HDR_FO_SHIFT	3
80 
81 #define	RTE_IPV4_HDR_DF_FLAG	(1 << RTE_IPV4_HDR_DF_SHIFT)
82 #define	RTE_IPV4_HDR_MF_FLAG	(1 << RTE_IPV4_HDR_MF_SHIFT)
83 
84 #define	RTE_IPV4_HDR_OFFSET_MASK	((1 << RTE_IPV4_HDR_MF_SHIFT) - 1)
85 
86 #define	RTE_IPV4_HDR_OFFSET_UNITS	8
87 
88 /*
89  * IPv4 address types
90  */
91 #define RTE_IPV4_ANY              ((uint32_t)0x00000000) /**< 0.0.0.0 */
92 #define RTE_IPV4_LOOPBACK         ((uint32_t)0x7f000001) /**< 127.0.0.1 */
93 #define RTE_IPV4_BROADCAST        ((uint32_t)0xe0000000) /**< 224.0.0.0 */
94 #define RTE_IPV4_ALLHOSTS_GROUP   ((uint32_t)0xe0000001) /**< 224.0.0.1 */
95 #define RTE_IPV4_ALLRTRS_GROUP    ((uint32_t)0xe0000002) /**< 224.0.0.2 */
96 #define RTE_IPV4_MAX_LOCAL_GROUP  ((uint32_t)0xe00000ff) /**< 224.0.0.255 */
97 
98 /*
99  * IPv4 Multicast-related macros
100  */
101 #define RTE_IPV4_MIN_MCAST \
102 	RTE_IPV4(224, 0, 0, 0)          /**< Minimal IPv4-multicast address */
103 #define RTE_IPV4_MAX_MCAST \
104 	RTE_IPV4(239, 255, 255, 255)    /**< Maximum IPv4 multicast address */
105 
106 #define RTE_IS_IPV4_MCAST(x) \
107 	((x) >= RTE_IPV4_MIN_MCAST && (x) <= RTE_IPV4_MAX_MCAST)
108 	/**< check if IPv4 address is multicast */
109 
110 /* IPv4 default fields values */
111 #define RTE_IPV4_MIN_IHL    (0x5)
112 #define RTE_IPV4_VHL_DEF    ((IPVERSION << 4) | RTE_IPV4_MIN_IHL)
113 
114 /**
115  * Get the length of an IPv4 header.
116  *
117  * @param ipv4_hdr
118  *   Pointer to the IPv4 header.
119  * @return
120  *   The length of the IPv4 header (with options if present) in bytes.
121  */
122 static inline uint8_t
123 rte_ipv4_hdr_len(const struct rte_ipv4_hdr *ipv4_hdr)
124 {
125 	return (uint8_t)((ipv4_hdr->version_ihl & RTE_IPV4_HDR_IHL_MASK) *
126 		RTE_IPV4_IHL_MULTIPLIER);
127 }
128 
129 /**
130  * @internal Calculate a sum of all words in the buffer.
131  * Helper routine for the rte_raw_cksum().
132  *
133  * @param buf
134  *   Pointer to the buffer.
135  * @param len
136  *   Length of the buffer.
137  * @param sum
138  *   Initial value of the sum.
139  * @return
140  *   sum += Sum of all words in the buffer.
141  */
142 static inline uint32_t
143 __rte_raw_cksum(const void *buf, size_t len, uint32_t sum)
144 {
145 	/* workaround gcc strict-aliasing warning */
146 	uintptr_t ptr = (uintptr_t)buf;
147 	typedef uint16_t __attribute__((__may_alias__)) u16_p;
148 	const u16_p *u16_buf = (const u16_p *)ptr;
149 
150 	while (len >= (sizeof(*u16_buf) * 4)) {
151 		sum += u16_buf[0];
152 		sum += u16_buf[1];
153 		sum += u16_buf[2];
154 		sum += u16_buf[3];
155 		len -= sizeof(*u16_buf) * 4;
156 		u16_buf += 4;
157 	}
158 	while (len >= sizeof(*u16_buf)) {
159 		sum += *u16_buf;
160 		len -= sizeof(*u16_buf);
161 		u16_buf += 1;
162 	}
163 
164 	/* if length is in odd bytes */
165 	if (len == 1) {
166 		uint16_t left = 0;
167 		*(uint8_t *)&left = *(const uint8_t *)u16_buf;
168 		sum += left;
169 	}
170 
171 	return sum;
172 }
173 
174 /**
175  * @internal Reduce a sum to the non-complemented checksum.
176  * Helper routine for the rte_raw_cksum().
177  *
178  * @param sum
179  *   Value of the sum.
180  * @return
181  *   The non-complemented checksum.
182  */
183 static inline uint16_t
184 __rte_raw_cksum_reduce(uint32_t sum)
185 {
186 	sum = ((sum & 0xffff0000) >> 16) + (sum & 0xffff);
187 	sum = ((sum & 0xffff0000) >> 16) + (sum & 0xffff);
188 	return (uint16_t)sum;
189 }
190 
191 /**
192  * Process the non-complemented checksum of a buffer.
193  *
194  * @param buf
195  *   Pointer to the buffer.
196  * @param len
197  *   Length of the buffer.
198  * @return
199  *   The non-complemented checksum.
200  */
201 static inline uint16_t
202 rte_raw_cksum(const void *buf, size_t len)
203 {
204 	uint32_t sum;
205 
206 	sum = __rte_raw_cksum(buf, len, 0);
207 	return __rte_raw_cksum_reduce(sum);
208 }
209 
210 /**
211  * Compute the raw (non complemented) checksum of a packet.
212  *
213  * @param m
214  *   The pointer to the mbuf.
215  * @param off
216  *   The offset in bytes to start the checksum.
217  * @param len
218  *   The length in bytes of the data to checksum.
219  * @param cksum
220  *   A pointer to the checksum, filled on success.
221  * @return
222  *   0 on success, -1 on error (bad length or offset).
223  */
224 static inline int
225 rte_raw_cksum_mbuf(const struct rte_mbuf *m, uint32_t off, uint32_t len,
226 	uint16_t *cksum)
227 {
228 	const struct rte_mbuf *seg;
229 	const char *buf;
230 	uint32_t sum, tmp;
231 	uint32_t seglen, done;
232 
233 	/* easy case: all data in the first segment */
234 	if (off + len <= rte_pktmbuf_data_len(m)) {
235 		*cksum = rte_raw_cksum(rte_pktmbuf_mtod_offset(m,
236 				const char *, off), len);
237 		return 0;
238 	}
239 
240 	if (unlikely(off + len > rte_pktmbuf_pkt_len(m)))
241 		return -1; /* invalid params, return a dummy value */
242 
243 	/* else browse the segment to find offset */
244 	seglen = 0;
245 	for (seg = m; seg != NULL; seg = seg->next) {
246 		seglen = rte_pktmbuf_data_len(seg);
247 		if (off < seglen)
248 			break;
249 		off -= seglen;
250 	}
251 	RTE_ASSERT(seg != NULL);
252 	if (seg == NULL)
253 		return -1;
254 	seglen -= off;
255 	buf = rte_pktmbuf_mtod_offset(seg, const char *, off);
256 	if (seglen >= len) {
257 		/* all in one segment */
258 		*cksum = rte_raw_cksum(buf, len);
259 		return 0;
260 	}
261 
262 	/* hard case: process checksum of several segments */
263 	sum = 0;
264 	done = 0;
265 	for (;;) {
266 		tmp = __rte_raw_cksum(buf, seglen, 0);
267 		if (done & 1)
268 			tmp = rte_bswap16((uint16_t)tmp);
269 		sum += tmp;
270 		done += seglen;
271 		if (done == len)
272 			break;
273 		seg = seg->next;
274 		buf = rte_pktmbuf_mtod(seg, const char *);
275 		seglen = rte_pktmbuf_data_len(seg);
276 		if (seglen > len - done)
277 			seglen = len - done;
278 	}
279 
280 	*cksum = __rte_raw_cksum_reduce(sum);
281 	return 0;
282 }
283 
284 /**
285  * Process the IPv4 checksum of an IPv4 header.
286  *
287  * The checksum field must be set to 0 by the caller.
288  *
289  * @param ipv4_hdr
290  *   The pointer to the contiguous IPv4 header.
291  * @return
292  *   The complemented checksum to set in the IP packet.
293  */
294 static inline uint16_t
295 rte_ipv4_cksum(const struct rte_ipv4_hdr *ipv4_hdr)
296 {
297 	uint16_t cksum;
298 	cksum = rte_raw_cksum(ipv4_hdr, rte_ipv4_hdr_len(ipv4_hdr));
299 	return (uint16_t)~cksum;
300 }
301 
302 /**
303  * Process the pseudo-header checksum of an IPv4 header.
304  *
305  * The checksum field must be set to 0 by the caller.
306  *
307  * Depending on the ol_flags, the pseudo-header checksum expected by the
308  * drivers is not the same. For instance, when TSO is enabled, the IP
309  * payload length must not be included in the packet.
310  *
311  * When ol_flags is 0, it computes the standard pseudo-header checksum.
312  *
313  * @param ipv4_hdr
314  *   The pointer to the contiguous IPv4 header.
315  * @param ol_flags
316  *   The ol_flags of the associated mbuf.
317  * @return
318  *   The non-complemented checksum to set in the L4 header.
319  */
320 static inline uint16_t
321 rte_ipv4_phdr_cksum(const struct rte_ipv4_hdr *ipv4_hdr, uint64_t ol_flags)
322 {
323 	struct ipv4_psd_header {
324 		uint32_t src_addr; /* IP address of source host. */
325 		uint32_t dst_addr; /* IP address of destination host. */
326 		uint8_t  zero;     /* zero. */
327 		uint8_t  proto;    /* L4 protocol type. */
328 		uint16_t len;      /* L4 length. */
329 	} psd_hdr;
330 
331 	uint32_t l3_len;
332 
333 	psd_hdr.src_addr = ipv4_hdr->src_addr;
334 	psd_hdr.dst_addr = ipv4_hdr->dst_addr;
335 	psd_hdr.zero = 0;
336 	psd_hdr.proto = ipv4_hdr->next_proto_id;
337 	if (ol_flags & PKT_TX_TCP_SEG) {
338 		psd_hdr.len = 0;
339 	} else {
340 		l3_len = rte_be_to_cpu_16(ipv4_hdr->total_length);
341 		psd_hdr.len = rte_cpu_to_be_16((uint16_t)(l3_len -
342 			rte_ipv4_hdr_len(ipv4_hdr)));
343 	}
344 	return rte_raw_cksum(&psd_hdr, sizeof(psd_hdr));
345 }
346 
347 /**
348  * @internal Calculate the non-complemented IPv4 L4 checksum
349  */
350 static inline uint16_t
351 __rte_ipv4_udptcp_cksum(const struct rte_ipv4_hdr *ipv4_hdr, const void *l4_hdr)
352 {
353 	uint32_t cksum;
354 	uint32_t l3_len, l4_len;
355 	uint8_t ip_hdr_len;
356 
357 	ip_hdr_len = rte_ipv4_hdr_len(ipv4_hdr);
358 	l3_len = rte_be_to_cpu_16(ipv4_hdr->total_length);
359 	if (l3_len < ip_hdr_len)
360 		return 0;
361 
362 	l4_len = l3_len - ip_hdr_len;
363 
364 	cksum = rte_raw_cksum(l4_hdr, l4_len);
365 	cksum += rte_ipv4_phdr_cksum(ipv4_hdr, 0);
366 
367 	cksum = ((cksum & 0xffff0000) >> 16) + (cksum & 0xffff);
368 
369 	return (uint16_t)cksum;
370 }
371 
372 /**
373  * Process the IPv4 UDP or TCP checksum.
374  *
375  * The layer 4 checksum must be set to 0 in the L4 header by the caller.
376  *
377  * @param ipv4_hdr
378  *   The pointer to the contiguous IPv4 header.
379  * @param l4_hdr
380  *   The pointer to the beginning of the L4 header.
381  * @return
382  *   The complemented checksum to set in the L4 header.
383  */
384 static inline uint16_t
385 rte_ipv4_udptcp_cksum(const struct rte_ipv4_hdr *ipv4_hdr, const void *l4_hdr)
386 {
387 	uint16_t cksum = __rte_ipv4_udptcp_cksum(ipv4_hdr, l4_hdr);
388 
389 	cksum = ~cksum;
390 
391 	/*
392 	 * Per RFC 768: If the computed checksum is zero for UDP,
393 	 * it is transmitted as all ones
394 	 * (the equivalent in one's complement arithmetic).
395 	 */
396 	if (cksum == 0 && ipv4_hdr->next_proto_id == IPPROTO_UDP)
397 		cksum = 0xffff;
398 
399 	return cksum;
400 }
401 
402 /**
403  * Validate the IPv4 UDP or TCP checksum.
404  *
405  * In case of UDP, the caller must first check if udp_hdr->dgram_cksum is 0
406  * (i.e. no checksum).
407  *
408  * @param ipv4_hdr
409  *   The pointer to the contiguous IPv4 header.
410  * @param l4_hdr
411  *   The pointer to the beginning of the L4 header.
412  * @return
413  *   Return 0 if the checksum is correct, else -1.
414  */
415 __rte_experimental
416 static inline int
417 rte_ipv4_udptcp_cksum_verify(const struct rte_ipv4_hdr *ipv4_hdr,
418 			     const void *l4_hdr)
419 {
420 	uint16_t cksum = __rte_ipv4_udptcp_cksum(ipv4_hdr, l4_hdr);
421 
422 	if (cksum != 0xffff)
423 		return -1;
424 
425 	return 0;
426 }
427 
428 /**
429  * IPv6 Header
430  */
431 struct rte_ipv6_hdr {
432 	rte_be32_t vtc_flow;	/**< IP version, traffic class & flow label. */
433 	rte_be16_t payload_len;	/**< IP payload size, including ext. headers */
434 	uint8_t  proto;		/**< Protocol, next header. */
435 	uint8_t  hop_limits;	/**< Hop limits. */
436 	uint8_t  src_addr[16];	/**< IP address of source host. */
437 	uint8_t  dst_addr[16];	/**< IP address of destination host(s). */
438 } __rte_packed;
439 
440 /* IPv6 vtc_flow: IPv / TC / flow_label */
441 #define RTE_IPV6_HDR_FL_SHIFT 0
442 #define RTE_IPV6_HDR_TC_SHIFT 20
443 #define RTE_IPV6_HDR_FL_MASK	((1u << RTE_IPV6_HDR_TC_SHIFT) - 1)
444 #define RTE_IPV6_HDR_TC_MASK	(0xff << RTE_IPV6_HDR_TC_SHIFT)
445 #define RTE_IPV6_HDR_DSCP_MASK	(0xfc << RTE_IPV6_HDR_TC_SHIFT)
446 #define RTE_IPV6_HDR_ECN_MASK	(0x03 << RTE_IPV6_HDR_TC_SHIFT)
447 #define RTE_IPV6_HDR_ECN_CE	RTE_IPV6_HDR_ECN_MASK
448 
449 #define RTE_IPV6_MIN_MTU 1280 /**< Minimum MTU for IPv6, see RFC 8200. */
450 
451 /**
452  * Process the pseudo-header checksum of an IPv6 header.
453  *
454  * Depending on the ol_flags, the pseudo-header checksum expected by the
455  * drivers is not the same. For instance, when TSO is enabled, the IPv6
456  * payload length must not be included in the packet.
457  *
458  * When ol_flags is 0, it computes the standard pseudo-header checksum.
459  *
460  * @param ipv6_hdr
461  *   The pointer to the contiguous IPv6 header.
462  * @param ol_flags
463  *   The ol_flags of the associated mbuf.
464  * @return
465  *   The non-complemented checksum to set in the L4 header.
466  */
467 static inline uint16_t
468 rte_ipv6_phdr_cksum(const struct rte_ipv6_hdr *ipv6_hdr, uint64_t ol_flags)
469 {
470 	uint32_t sum;
471 	struct {
472 		rte_be32_t len;   /* L4 length. */
473 		rte_be32_t proto; /* L4 protocol - top 3 bytes must be zero */
474 	} psd_hdr;
475 
476 	psd_hdr.proto = (uint32_t)(ipv6_hdr->proto << 24);
477 	if (ol_flags & PKT_TX_TCP_SEG) {
478 		psd_hdr.len = 0;
479 	} else {
480 		psd_hdr.len = ipv6_hdr->payload_len;
481 	}
482 
483 	sum = __rte_raw_cksum(ipv6_hdr->src_addr,
484 		sizeof(ipv6_hdr->src_addr) + sizeof(ipv6_hdr->dst_addr),
485 		0);
486 	sum = __rte_raw_cksum(&psd_hdr, sizeof(psd_hdr), sum);
487 	return __rte_raw_cksum_reduce(sum);
488 }
489 
490 /**
491  * @internal Calculate the non-complemented IPv6 L4 checksum
492  */
493 static inline uint16_t
494 __rte_ipv6_udptcp_cksum(const struct rte_ipv6_hdr *ipv6_hdr, const void *l4_hdr)
495 {
496 	uint32_t cksum;
497 	uint32_t l4_len;
498 
499 	l4_len = rte_be_to_cpu_16(ipv6_hdr->payload_len);
500 
501 	cksum = rte_raw_cksum(l4_hdr, l4_len);
502 	cksum += rte_ipv6_phdr_cksum(ipv6_hdr, 0);
503 
504 	cksum = ((cksum & 0xffff0000) >> 16) + (cksum & 0xffff);
505 
506 	return (uint16_t)cksum;
507 }
508 
509 /**
510  * Process the IPv6 UDP or TCP checksum.
511  *
512  * The IPv6 header must not be followed by extension headers. The layer 4
513  * checksum must be set to 0 in the L4 header by the caller.
514  *
515  * @param ipv6_hdr
516  *   The pointer to the contiguous IPv6 header.
517  * @param l4_hdr
518  *   The pointer to the beginning of the L4 header.
519  * @return
520  *   The complemented checksum to set in the L4 header.
521  */
522 static inline uint16_t
523 rte_ipv6_udptcp_cksum(const struct rte_ipv6_hdr *ipv6_hdr, const void *l4_hdr)
524 {
525 	uint16_t cksum = __rte_ipv6_udptcp_cksum(ipv6_hdr, l4_hdr);
526 
527 	cksum = ~cksum;
528 
529 	/*
530 	 * Per RFC 768: If the computed checksum is zero for UDP,
531 	 * it is transmitted as all ones
532 	 * (the equivalent in one's complement arithmetic).
533 	 */
534 	if (cksum == 0 && ipv6_hdr->proto == IPPROTO_UDP)
535 		cksum = 0xffff;
536 
537 	return cksum;
538 }
539 
540 /**
541  * Validate the IPv6 UDP or TCP checksum.
542  *
543  * In case of UDP, the caller must first check if udp_hdr->dgram_cksum is 0:
544  * this is either invalid or means no checksum in some situations. See 8.1
545  * (Upper-Layer Checksums) in RFC 8200.
546  *
547  * @param ipv6_hdr
548  *   The pointer to the contiguous IPv6 header.
549  * @param l4_hdr
550  *   The pointer to the beginning of the L4 header.
551  * @return
552  *   Return 0 if the checksum is correct, else -1.
553  */
554 __rte_experimental
555 static inline int
556 rte_ipv6_udptcp_cksum_verify(const struct rte_ipv6_hdr *ipv6_hdr,
557 			     const void *l4_hdr)
558 {
559 	uint16_t cksum = __rte_ipv6_udptcp_cksum(ipv6_hdr, l4_hdr);
560 
561 	if (cksum != 0xffff)
562 		return -1;
563 
564 	return 0;
565 }
566 
567 /** IPv6 fragment extension header. */
568 #define	RTE_IPV6_EHDR_MF_SHIFT	0
569 #define	RTE_IPV6_EHDR_MF_MASK	1
570 #define	RTE_IPV6_EHDR_FO_SHIFT	3
571 #define	RTE_IPV6_EHDR_FO_MASK	(~((1 << RTE_IPV6_EHDR_FO_SHIFT) - 1))
572 #define	RTE_IPV6_EHDR_FO_ALIGN	(1 << RTE_IPV6_EHDR_FO_SHIFT)
573 
574 #define RTE_IPV6_FRAG_USED_MASK	(RTE_IPV6_EHDR_MF_MASK | RTE_IPV6_EHDR_FO_MASK)
575 
576 #define RTE_IPV6_GET_MF(x)	((x) & RTE_IPV6_EHDR_MF_MASK)
577 #define RTE_IPV6_GET_FO(x)	((x) >> RTE_IPV6_EHDR_FO_SHIFT)
578 
579 #define RTE_IPV6_SET_FRAG_DATA(fo, mf)	\
580 	(((fo) & RTE_IPV6_EHDR_FO_MASK) | ((mf) & RTE_IPV6_EHDR_MF_MASK))
581 
582 struct rte_ipv6_fragment_ext {
583 	uint8_t next_header;	/**< Next header type */
584 	uint8_t reserved;	/**< Reserved */
585 	rte_be16_t frag_data;	/**< All fragmentation data */
586 	rte_be32_t id;		/**< Packet ID */
587 } __rte_packed;
588 
589 /* IPv6 fragment extension header size */
590 #define RTE_IPV6_FRAG_HDR_SIZE	sizeof(struct rte_ipv6_fragment_ext)
591 
592 /**
593  * Parse next IPv6 header extension
594  *
595  * This function checks if proto number is an IPv6 extensions and parses its
596  * data if so, providing information on next header and extension length.
597  *
598  * @param p
599  *   Pointer to an extension raw data.
600  * @param proto
601  *   Protocol number extracted from the "next header" field from
602  *   the IPv6 header or the previous extension.
603  * @param ext_len
604  *   Extension data length.
605  * @return
606  *   next protocol number if proto is an IPv6 extension, -EINVAL otherwise
607  */
608 __rte_experimental
609 static inline int
610 rte_ipv6_get_next_ext(const uint8_t *p, int proto, size_t *ext_len)
611 {
612 	int next_proto;
613 
614 	switch (proto) {
615 	case IPPROTO_AH:
616 		next_proto = *p++;
617 		*ext_len = (*p + 2) * sizeof(uint32_t);
618 		break;
619 
620 	case IPPROTO_HOPOPTS:
621 	case IPPROTO_ROUTING:
622 	case IPPROTO_DSTOPTS:
623 		next_proto = *p++;
624 		*ext_len = (*p + 1) * sizeof(uint64_t);
625 		break;
626 
627 	case IPPROTO_FRAGMENT:
628 		next_proto = *p;
629 		*ext_len = RTE_IPV6_FRAG_HDR_SIZE;
630 		break;
631 
632 	default:
633 		return -EINVAL;
634 	}
635 
636 	return next_proto;
637 }
638 
639 #ifdef __cplusplus
640 }
641 #endif
642 
643 #endif /* _RTE_IP_H_ */
644