1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0-only
2*4882a593Smuzhiyun /**
3*4882a593Smuzhiyun * Authors:
4*4882a593Smuzhiyun * (C) 2020 Alexander Aring <alex.aring@gmail.com>
5*4882a593Smuzhiyun */
6*4882a593Smuzhiyun
7*4882a593Smuzhiyun #include <net/ipv6.h>
8*4882a593Smuzhiyun #include <net/rpl.h>
9*4882a593Smuzhiyun
10*4882a593Smuzhiyun #define IPV6_PFXTAIL_LEN(x) (sizeof(struct in6_addr) - (x))
11*4882a593Smuzhiyun #define IPV6_RPL_BEST_ADDR_COMPRESSION 15
12*4882a593Smuzhiyun
ipv6_rpl_addr_decompress(struct in6_addr * dst,const struct in6_addr * daddr,const void * post,unsigned char pfx)13*4882a593Smuzhiyun static void ipv6_rpl_addr_decompress(struct in6_addr *dst,
14*4882a593Smuzhiyun const struct in6_addr *daddr,
15*4882a593Smuzhiyun const void *post, unsigned char pfx)
16*4882a593Smuzhiyun {
17*4882a593Smuzhiyun memcpy(dst, daddr, pfx);
18*4882a593Smuzhiyun memcpy(&dst->s6_addr[pfx], post, IPV6_PFXTAIL_LEN(pfx));
19*4882a593Smuzhiyun }
20*4882a593Smuzhiyun
ipv6_rpl_addr_compress(void * dst,const struct in6_addr * addr,unsigned char pfx)21*4882a593Smuzhiyun static void ipv6_rpl_addr_compress(void *dst, const struct in6_addr *addr,
22*4882a593Smuzhiyun unsigned char pfx)
23*4882a593Smuzhiyun {
24*4882a593Smuzhiyun memcpy(dst, &addr->s6_addr[pfx], IPV6_PFXTAIL_LEN(pfx));
25*4882a593Smuzhiyun }
26*4882a593Smuzhiyun
ipv6_rpl_segdata_pos(const struct ipv6_rpl_sr_hdr * hdr,int i)27*4882a593Smuzhiyun static void *ipv6_rpl_segdata_pos(const struct ipv6_rpl_sr_hdr *hdr, int i)
28*4882a593Smuzhiyun {
29*4882a593Smuzhiyun return (void *)&hdr->rpl_segdata[i * IPV6_PFXTAIL_LEN(hdr->cmpri)];
30*4882a593Smuzhiyun }
31*4882a593Smuzhiyun
ipv6_rpl_srh_size(unsigned char n,unsigned char cmpri,unsigned char cmpre)32*4882a593Smuzhiyun size_t ipv6_rpl_srh_size(unsigned char n, unsigned char cmpri,
33*4882a593Smuzhiyun unsigned char cmpre)
34*4882a593Smuzhiyun {
35*4882a593Smuzhiyun return (n * IPV6_PFXTAIL_LEN(cmpri)) + IPV6_PFXTAIL_LEN(cmpre);
36*4882a593Smuzhiyun }
37*4882a593Smuzhiyun
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)38*4882a593Smuzhiyun void ipv6_rpl_srh_decompress(struct ipv6_rpl_sr_hdr *outhdr,
39*4882a593Smuzhiyun const struct ipv6_rpl_sr_hdr *inhdr,
40*4882a593Smuzhiyun const struct in6_addr *daddr, unsigned char n)
41*4882a593Smuzhiyun {
42*4882a593Smuzhiyun int i;
43*4882a593Smuzhiyun
44*4882a593Smuzhiyun outhdr->nexthdr = inhdr->nexthdr;
45*4882a593Smuzhiyun outhdr->hdrlen = (((n + 1) * sizeof(struct in6_addr)) >> 3);
46*4882a593Smuzhiyun outhdr->pad = 0;
47*4882a593Smuzhiyun outhdr->type = inhdr->type;
48*4882a593Smuzhiyun outhdr->segments_left = inhdr->segments_left;
49*4882a593Smuzhiyun outhdr->cmpri = 0;
50*4882a593Smuzhiyun outhdr->cmpre = 0;
51*4882a593Smuzhiyun
52*4882a593Smuzhiyun for (i = 0; i < n; i++)
53*4882a593Smuzhiyun ipv6_rpl_addr_decompress(&outhdr->rpl_segaddr[i], daddr,
54*4882a593Smuzhiyun ipv6_rpl_segdata_pos(inhdr, i),
55*4882a593Smuzhiyun inhdr->cmpri);
56*4882a593Smuzhiyun
57*4882a593Smuzhiyun ipv6_rpl_addr_decompress(&outhdr->rpl_segaddr[n], daddr,
58*4882a593Smuzhiyun ipv6_rpl_segdata_pos(inhdr, n),
59*4882a593Smuzhiyun inhdr->cmpre);
60*4882a593Smuzhiyun }
61*4882a593Smuzhiyun
ipv6_rpl_srh_calc_cmpri(const struct ipv6_rpl_sr_hdr * inhdr,const struct in6_addr * daddr,unsigned char n)62*4882a593Smuzhiyun static unsigned char ipv6_rpl_srh_calc_cmpri(const struct ipv6_rpl_sr_hdr *inhdr,
63*4882a593Smuzhiyun const struct in6_addr *daddr,
64*4882a593Smuzhiyun unsigned char n)
65*4882a593Smuzhiyun {
66*4882a593Smuzhiyun unsigned char plen;
67*4882a593Smuzhiyun int i;
68*4882a593Smuzhiyun
69*4882a593Smuzhiyun for (plen = 0; plen < sizeof(*daddr); plen++) {
70*4882a593Smuzhiyun for (i = 0; i < n; i++) {
71*4882a593Smuzhiyun if (daddr->s6_addr[plen] !=
72*4882a593Smuzhiyun inhdr->rpl_segaddr[i].s6_addr[plen])
73*4882a593Smuzhiyun return plen;
74*4882a593Smuzhiyun }
75*4882a593Smuzhiyun }
76*4882a593Smuzhiyun
77*4882a593Smuzhiyun return IPV6_RPL_BEST_ADDR_COMPRESSION;
78*4882a593Smuzhiyun }
79*4882a593Smuzhiyun
ipv6_rpl_srh_calc_cmpre(const struct in6_addr * daddr,const struct in6_addr * last_segment)80*4882a593Smuzhiyun static unsigned char ipv6_rpl_srh_calc_cmpre(const struct in6_addr *daddr,
81*4882a593Smuzhiyun const struct in6_addr *last_segment)
82*4882a593Smuzhiyun {
83*4882a593Smuzhiyun unsigned int plen;
84*4882a593Smuzhiyun
85*4882a593Smuzhiyun for (plen = 0; plen < sizeof(*daddr); plen++) {
86*4882a593Smuzhiyun if (daddr->s6_addr[plen] != last_segment->s6_addr[plen])
87*4882a593Smuzhiyun return plen;
88*4882a593Smuzhiyun }
89*4882a593Smuzhiyun
90*4882a593Smuzhiyun return IPV6_RPL_BEST_ADDR_COMPRESSION;
91*4882a593Smuzhiyun }
92*4882a593Smuzhiyun
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)93*4882a593Smuzhiyun void ipv6_rpl_srh_compress(struct ipv6_rpl_sr_hdr *outhdr,
94*4882a593Smuzhiyun const struct ipv6_rpl_sr_hdr *inhdr,
95*4882a593Smuzhiyun const struct in6_addr *daddr, unsigned char n)
96*4882a593Smuzhiyun {
97*4882a593Smuzhiyun unsigned char cmpri, cmpre;
98*4882a593Smuzhiyun size_t seglen;
99*4882a593Smuzhiyun int i;
100*4882a593Smuzhiyun
101*4882a593Smuzhiyun cmpri = ipv6_rpl_srh_calc_cmpri(inhdr, daddr, n);
102*4882a593Smuzhiyun cmpre = ipv6_rpl_srh_calc_cmpre(daddr, &inhdr->rpl_segaddr[n]);
103*4882a593Smuzhiyun
104*4882a593Smuzhiyun outhdr->nexthdr = inhdr->nexthdr;
105*4882a593Smuzhiyun seglen = (n * IPV6_PFXTAIL_LEN(cmpri)) + IPV6_PFXTAIL_LEN(cmpre);
106*4882a593Smuzhiyun outhdr->hdrlen = seglen >> 3;
107*4882a593Smuzhiyun if (seglen & 0x7) {
108*4882a593Smuzhiyun outhdr->hdrlen++;
109*4882a593Smuzhiyun outhdr->pad = 8 - (seglen & 0x7);
110*4882a593Smuzhiyun } else {
111*4882a593Smuzhiyun outhdr->pad = 0;
112*4882a593Smuzhiyun }
113*4882a593Smuzhiyun outhdr->type = inhdr->type;
114*4882a593Smuzhiyun outhdr->segments_left = inhdr->segments_left;
115*4882a593Smuzhiyun outhdr->cmpri = cmpri;
116*4882a593Smuzhiyun outhdr->cmpre = cmpre;
117*4882a593Smuzhiyun
118*4882a593Smuzhiyun for (i = 0; i < n; i++)
119*4882a593Smuzhiyun ipv6_rpl_addr_compress(ipv6_rpl_segdata_pos(outhdr, i),
120*4882a593Smuzhiyun &inhdr->rpl_segaddr[i], cmpri);
121*4882a593Smuzhiyun
122*4882a593Smuzhiyun ipv6_rpl_addr_compress(ipv6_rpl_segdata_pos(outhdr, n),
123*4882a593Smuzhiyun &inhdr->rpl_segaddr[n], cmpre);
124*4882a593Smuzhiyun }
125