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8610c7c6 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
f1f09df1 | 2 | /* |
8610c7c6 AA |
3 | * Authors: |
4 | * (C) 2020 Alexander Aring <alex.aring@gmail.com> | |
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 | { | |
4e006c7a AA |
35 | return sizeof(struct ipv6_rpl_sr_hdr) + (n * IPV6_PFXTAIL_LEN(cmpri)) + |
36 | IPV6_PFXTAIL_LEN(cmpre); | |
8610c7c6 AA |
37 | } |
38 | ||
39 | void ipv6_rpl_srh_decompress(struct ipv6_rpl_sr_hdr *outhdr, | |
40 | const struct ipv6_rpl_sr_hdr *inhdr, | |
41 | const struct in6_addr *daddr, unsigned char n) | |
42 | { | |
43 | int i; | |
44 | ||
45 | outhdr->nexthdr = inhdr->nexthdr; | |
46 | outhdr->hdrlen = (((n + 1) * sizeof(struct in6_addr)) >> 3); | |
47 | outhdr->pad = 0; | |
48 | outhdr->type = inhdr->type; | |
49 | outhdr->segments_left = inhdr->segments_left; | |
50 | outhdr->cmpri = 0; | |
51 | outhdr->cmpre = 0; | |
52 | ||
a7f9a6f4 | 53 | for (i = 0; i < n; i++) |
8610c7c6 AA |
54 | ipv6_rpl_addr_decompress(&outhdr->rpl_segaddr[i], daddr, |
55 | ipv6_rpl_segdata_pos(inhdr, i), | |
56 | inhdr->cmpri); | |
57 | ||
58 | ipv6_rpl_addr_decompress(&outhdr->rpl_segaddr[n], daddr, | |
59 | ipv6_rpl_segdata_pos(inhdr, n), | |
60 | inhdr->cmpre); | |
61 | } | |
62 | ||
63 | static unsigned char ipv6_rpl_srh_calc_cmpri(const struct ipv6_rpl_sr_hdr *inhdr, | |
64 | const struct in6_addr *daddr, | |
65 | unsigned char n) | |
66 | { | |
67 | unsigned char plen; | |
68 | int i; | |
69 | ||
70 | for (plen = 0; plen < sizeof(*daddr); plen++) { | |
a7f9a6f4 | 71 | for (i = 0; i < n; i++) { |
8610c7c6 AA |
72 | if (daddr->s6_addr[plen] != |
73 | inhdr->rpl_segaddr[i].s6_addr[plen]) | |
74 | return plen; | |
75 | } | |
76 | } | |
77 | ||
62e69776 | 78 | return IPV6_RPL_BEST_ADDR_COMPRESSION; |
8610c7c6 AA |
79 | } |
80 | ||
81 | static unsigned char ipv6_rpl_srh_calc_cmpre(const struct in6_addr *daddr, | |
82 | const struct in6_addr *last_segment) | |
83 | { | |
84 | unsigned int plen; | |
85 | ||
86 | for (plen = 0; plen < sizeof(*daddr); plen++) { | |
87 | if (daddr->s6_addr[plen] != last_segment->s6_addr[plen]) | |
62e69776 | 88 | return plen; |
8610c7c6 AA |
89 | } |
90 | ||
62e69776 | 91 | return IPV6_RPL_BEST_ADDR_COMPRESSION; |
8610c7c6 AA |
92 | } |
93 | ||
94 | void ipv6_rpl_srh_compress(struct ipv6_rpl_sr_hdr *outhdr, | |
95 | const struct ipv6_rpl_sr_hdr *inhdr, | |
96 | const struct in6_addr *daddr, unsigned char n) | |
97 | { | |
98 | unsigned char cmpri, cmpre; | |
99 | size_t seglen; | |
100 | int i; | |
101 | ||
102 | cmpri = ipv6_rpl_srh_calc_cmpri(inhdr, daddr, n); | |
103 | cmpre = ipv6_rpl_srh_calc_cmpre(daddr, &inhdr->rpl_segaddr[n]); | |
104 | ||
105 | outhdr->nexthdr = inhdr->nexthdr; | |
106 | seglen = (n * IPV6_PFXTAIL_LEN(cmpri)) + IPV6_PFXTAIL_LEN(cmpre); | |
107 | outhdr->hdrlen = seglen >> 3; | |
108 | if (seglen & 0x7) { | |
109 | outhdr->hdrlen++; | |
110 | outhdr->pad = 8 - (seglen & 0x7); | |
111 | } else { | |
112 | outhdr->pad = 0; | |
113 | } | |
114 | outhdr->type = inhdr->type; | |
115 | outhdr->segments_left = inhdr->segments_left; | |
116 | outhdr->cmpri = cmpri; | |
117 | outhdr->cmpre = cmpre; | |
118 | ||
a7f9a6f4 | 119 | for (i = 0; i < n; i++) |
8610c7c6 AA |
120 | ipv6_rpl_addr_compress(ipv6_rpl_segdata_pos(outhdr, i), |
121 | &inhdr->rpl_segaddr[i], cmpri); | |
122 | ||
123 | ipv6_rpl_addr_compress(ipv6_rpl_segdata_pos(outhdr, n), | |
124 | &inhdr->rpl_segaddr[n], cmpre); | |
125 | } |