[linux.git] / net / ipv6 / rpl.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Authors:
 * (C) 2020 Alexander Aring <[email protected]>
 */

#include <net/ipv6.h>
#include <net/rpl.h>

#define IPV6_PFXTAIL_LEN(x) (sizeof(struct in6_addr) - (x))
#define IPV6_RPL_BEST_ADDR_COMPRESSION 15

static void ipv6_rpl_addr_decompress(struct in6_addr *dst,
				     const struct in6_addr *daddr,
				     const void *post, unsigned char pfx)
{
	memcpy(dst, daddr, pfx);
	memcpy(&dst->s6_addr[pfx], post, IPV6_PFXTAIL_LEN(pfx));
}

static void ipv6_rpl_addr_compress(void *dst, const struct in6_addr *addr,
				   unsigned char pfx)
{
	memcpy(dst, &addr->s6_addr[pfx], IPV6_PFXTAIL_LEN(pfx));
}

static void *ipv6_rpl_segdata_pos(const struct ipv6_rpl_sr_hdr *hdr, int i)
{
	return (void *)&hdr->rpl_segdata[i * IPV6_PFXTAIL_LEN(hdr->cmpri)];
}

size_t ipv6_rpl_srh_size(unsigned char n, unsigned char cmpri,
			 unsigned char cmpre)
{
	return (n * IPV6_PFXTAIL_LEN(cmpri)) + IPV6_PFXTAIL_LEN(cmpre);
}

void ipv6_rpl_srh_decompress(struct ipv6_rpl_sr_hdr *outhdr,
			     const struct ipv6_rpl_sr_hdr *inhdr,
			     const struct in6_addr *daddr, unsigned char n)
{
	int i;

	outhdr->nexthdr = inhdr->nexthdr;
	outhdr->hdrlen = (((n + 1) * sizeof(struct in6_addr)) >> 3);
	outhdr->pad = 0;
	outhdr->type = inhdr->type;
	outhdr->segments_left = inhdr->segments_left;
	outhdr->cmpri = 0;
	outhdr->cmpre = 0;

	for (i = 0; i < n; i++)
		ipv6_rpl_addr_decompress(&outhdr->rpl_segaddr[i], daddr,
					 ipv6_rpl_segdata_pos(inhdr, i),
					 inhdr->cmpri);

	ipv6_rpl_addr_decompress(&outhdr->rpl_segaddr[n], daddr,
				 ipv6_rpl_segdata_pos(inhdr, n),
				 inhdr->cmpre);
}

static unsigned char ipv6_rpl_srh_calc_cmpri(const struct ipv6_rpl_sr_hdr *inhdr,
					     const struct in6_addr *daddr,
					     unsigned char n)
{
	unsigned char plen;
	int i;

	for (plen = 0; plen < sizeof(*daddr); plen++) {
		for (i = 0; i < n; i++) {
			if (daddr->s6_addr[plen] !=
			    inhdr->rpl_segaddr[i].s6_addr[plen])
				return plen;
		}
	}

	return IPV6_RPL_BEST_ADDR_COMPRESSION;
}

static unsigned char ipv6_rpl_srh_calc_cmpre(const struct in6_addr *daddr,
					     const struct in6_addr *last_segment)
{
	unsigned int plen;

	for (plen = 0; plen < sizeof(*daddr); plen++) {
		if (daddr->s6_addr[plen] != last_segment->s6_addr[plen])
			return plen;
	}

	return IPV6_RPL_BEST_ADDR_COMPRESSION;
}

void ipv6_rpl_srh_compress(struct ipv6_rpl_sr_hdr *outhdr,
			   const struct ipv6_rpl_sr_hdr *inhdr,
			   const struct in6_addr *daddr, unsigned char n)
{
	unsigned char cmpri, cmpre;
	size_t seglen;
	int i;

	cmpri = ipv6_rpl_srh_calc_cmpri(inhdr, daddr, n);
	cmpre = ipv6_rpl_srh_calc_cmpre(daddr, &inhdr->rpl_segaddr[n]);

	outhdr->nexthdr = inhdr->nexthdr;
	seglen = (n * IPV6_PFXTAIL_LEN(cmpri)) + IPV6_PFXTAIL_LEN(cmpre);
	outhdr->hdrlen = seglen >> 3;
	if (seglen & 0x7) {
		outhdr->hdrlen++;
		outhdr->pad = 8 - (seglen & 0x7);
	} else {
		outhdr->pad = 0;
	}
	outhdr->type = inhdr->type;
	outhdr->segments_left = inhdr->segments_left;
	outhdr->cmpri = cmpri;
	outhdr->cmpre = cmpre;

	for (i = 0; i < n; i++)
		ipv6_rpl_addr_compress(ipv6_rpl_segdata_pos(outhdr, i),
				       &inhdr->rpl_segaddr[i], cmpri);

	ipv6_rpl_addr_compress(ipv6_rpl_segdata_pos(outhdr, n),
			       &inhdr->rpl_segaddr[n], cmpre);
}
Commit	Line	Data
8610c7c6	1	// SPDX-License-Identifier: GPL-2.0-only
f1f09df1	2	/*
8610c7c6 AA	3	* Authors:
	4	* (C) 2020 Alexander Aring <[email protected]>
	5	*/
	6
	7	#include <net/ipv6.h>
	8	#include <net/rpl.h>
	9
	10	#define IPV6_PFXTAIL_LEN(x) (sizeof(struct in6_addr) - (x))
62e69776	11	#define IPV6_RPL_BEST_ADDR_COMPRESSION 15
8610c7c6 AA	12
	13	static void ipv6_rpl_addr_decompress(struct in6_addr *dst,
	14	const struct in6_addr *daddr,
	15	const void *post, unsigned char pfx)
	16	{
	17	memcpy(dst, daddr, pfx);
	18	memcpy(&dst->s6_addr[pfx], post, IPV6_PFXTAIL_LEN(pfx));
	19	}
	20
	21	static void ipv6_rpl_addr_compress(void dst, const struct in6_addr addr,
	22	unsigned char pfx)
	23	{
	24	memcpy(dst, &addr->s6_addr[pfx], IPV6_PFXTAIL_LEN(pfx));
	25	}
	26
	27	static void ipv6_rpl_segdata_pos(const struct ipv6_rpl_sr_hdr hdr, int i)
	28	{
	29	return (void )&hdr->rpl_segdata[i IPV6_PFXTAIL_LEN(hdr->cmpri)];
	30	}
	31
	32	size_t ipv6_rpl_srh_size(unsigned char n, unsigned char cmpri,
	33	unsigned char cmpre)
	34	{
	35	return (n * IPV6_PFXTAIL_LEN(cmpri)) + IPV6_PFXTAIL_LEN(cmpre);
	36	}
	37
	38	void ipv6_rpl_srh_decompress(struct ipv6_rpl_sr_hdr *outhdr,
	39	const struct ipv6_rpl_sr_hdr *inhdr,
	40	const struct in6_addr *daddr, unsigned char n)
	41	{
	42	int i;
	43
	44	outhdr->nexthdr = inhdr->nexthdr;
	45	outhdr->hdrlen = (((n + 1) * sizeof(struct in6_addr)) >> 3);
	46	outhdr->pad = 0;
	47	outhdr->type = inhdr->type;
	48	outhdr->segments_left = inhdr->segments_left;
	49	outhdr->cmpri = 0;
	50	outhdr->cmpre = 0;
	51
a7f9a6f4	52	for (i = 0; i < n; i++)
8610c7c6 AA	53	ipv6_rpl_addr_decompress(&outhdr->rpl_segaddr[i], daddr,
	54	ipv6_rpl_segdata_pos(inhdr, i),
	55	inhdr->cmpri);
	56
	57	ipv6_rpl_addr_decompress(&outhdr->rpl_segaddr[n], daddr,
	58	ipv6_rpl_segdata_pos(inhdr, n),
	59	inhdr->cmpre);
	60	}
	61
	62	static unsigned char ipv6_rpl_srh_calc_cmpri(const struct ipv6_rpl_sr_hdr *inhdr,
	63	const struct in6_addr *daddr,
	64	unsigned char n)
	65	{
	66	unsigned char plen;
	67	int i;
	68
	69	for (plen = 0; plen < sizeof(*daddr); plen++) {
a7f9a6f4	70	for (i = 0; i < n; i++) {
8610c7c6 AA	71	if (daddr->s6_addr[plen] !=
	72	inhdr->rpl_segaddr[i].s6_addr[plen])
	73	return plen;
	74	}
	75	}
	76
62e69776	77	return IPV6_RPL_BEST_ADDR_COMPRESSION;
8610c7c6 AA	78	}
	79
	80	static unsigned char ipv6_rpl_srh_calc_cmpre(const struct in6_addr *daddr,
	81	const struct in6_addr *last_segment)
	82	{
	83	unsigned int plen;
	84
	85	for (plen = 0; plen < sizeof(*daddr); plen++) {
	86	if (daddr->s6_addr[plen] != last_segment->s6_addr[plen])
62e69776	87	return plen;
8610c7c6 AA	88	}
8610c7c6 AA	89
62e69776	90	return IPV6_RPL_BEST_ADDR_COMPRESSION;
8610c7c6 AA	91	}
	92
	93	void ipv6_rpl_srh_compress(struct ipv6_rpl_sr_hdr *outhdr,
	94	const struct ipv6_rpl_sr_hdr *inhdr,
	95	const struct in6_addr *daddr, unsigned char n)
	96	{
	97	unsigned char cmpri, cmpre;
	98	size_t seglen;
	99	int i;
	100
	101	cmpri = ipv6_rpl_srh_calc_cmpri(inhdr, daddr, n);
	102	cmpre = ipv6_rpl_srh_calc_cmpre(daddr, &inhdr->rpl_segaddr[n]);
	103
	104	outhdr->nexthdr = inhdr->nexthdr;
	105	seglen = (n * IPV6_PFXTAIL_LEN(cmpri)) + IPV6_PFXTAIL_LEN(cmpre);
	106	outhdr->hdrlen = seglen >> 3;
	107	if (seglen & 0x7) {
	108	outhdr->hdrlen++;
	109	outhdr->pad = 8 - (seglen & 0x7);
	110	} else {
	111	outhdr->pad = 0;
	112	}
	113	outhdr->type = inhdr->type;
	114	outhdr->segments_left = inhdr->segments_left;
	115	outhdr->cmpri = cmpri;
	116	outhdr->cmpre = cmpre;
	117
a7f9a6f4	118	for (i = 0; i < n; i++)
8610c7c6 AA	119	ipv6_rpl_addr_compress(ipv6_rpl_segdata_pos(outhdr, i),
	120	&inhdr->rpl_segaddr[i], cmpri);
	121
	122	ipv6_rpl_addr_compress(ipv6_rpl_segdata_pos(outhdr, n),
	123	&inhdr->rpl_segaddr[n], cmpre);
	124	}