119 lines
3.0 KiB
C
119 lines
3.0 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Authors:
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* (C) 2020 Alexander Aring <alex.aring@gmail.com>
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*/
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#include <net/ipv6.h>
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#include <net/rpl.h>
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#define IPV6_PFXTAIL_LEN(x) (sizeof(struct in6_addr) - (x))
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#define IPV6_RPL_BEST_ADDR_COMPRESSION 15
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static void ipv6_rpl_addr_decompress(struct in6_addr *dst,
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const struct in6_addr *daddr,
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const void *post, unsigned char pfx)
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{
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memcpy(dst, daddr, pfx);
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memcpy(&dst->s6_addr[pfx], post, IPV6_PFXTAIL_LEN(pfx));
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}
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static void ipv6_rpl_addr_compress(void *dst, const struct in6_addr *addr,
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unsigned char pfx)
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{
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memcpy(dst, &addr->s6_addr[pfx], IPV6_PFXTAIL_LEN(pfx));
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}
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static void *ipv6_rpl_segdata_pos(const struct ipv6_rpl_sr_hdr *hdr, int i)
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{
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return (void *)&hdr->rpl_segdata[i * IPV6_PFXTAIL_LEN(hdr->cmpri)];
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}
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void ipv6_rpl_srh_decompress(struct ipv6_rpl_sr_hdr *outhdr,
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const struct ipv6_rpl_sr_hdr *inhdr,
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const struct in6_addr *daddr, unsigned char n)
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{
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int i;
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outhdr->nexthdr = inhdr->nexthdr;
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outhdr->hdrlen = (((n + 1) * sizeof(struct in6_addr)) >> 3);
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outhdr->pad = 0;
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outhdr->type = inhdr->type;
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outhdr->segments_left = inhdr->segments_left;
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outhdr->cmpri = 0;
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outhdr->cmpre = 0;
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for (i = 0; i < n; i++)
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ipv6_rpl_addr_decompress(&outhdr->rpl_segaddr[i], daddr,
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ipv6_rpl_segdata_pos(inhdr, i),
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inhdr->cmpri);
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ipv6_rpl_addr_decompress(&outhdr->rpl_segaddr[n], daddr,
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ipv6_rpl_segdata_pos(inhdr, n),
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inhdr->cmpre);
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}
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static unsigned char ipv6_rpl_srh_calc_cmpri(const struct ipv6_rpl_sr_hdr *inhdr,
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const struct in6_addr *daddr,
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unsigned char n)
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{
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unsigned char plen;
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int i;
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for (plen = 0; plen < sizeof(*daddr); plen++) {
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for (i = 0; i < n; i++) {
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if (daddr->s6_addr[plen] !=
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inhdr->rpl_segaddr[i].s6_addr[plen])
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return plen;
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}
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}
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return IPV6_RPL_BEST_ADDR_COMPRESSION;
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}
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static unsigned char ipv6_rpl_srh_calc_cmpre(const struct in6_addr *daddr,
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const struct in6_addr *last_segment)
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{
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unsigned int plen;
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for (plen = 0; plen < sizeof(*daddr); plen++) {
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if (daddr->s6_addr[plen] != last_segment->s6_addr[plen])
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return plen;
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}
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return IPV6_RPL_BEST_ADDR_COMPRESSION;
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}
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void ipv6_rpl_srh_compress(struct ipv6_rpl_sr_hdr *outhdr,
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const struct ipv6_rpl_sr_hdr *inhdr,
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const struct in6_addr *daddr, unsigned char n)
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{
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unsigned char cmpri, cmpre;
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size_t seglen;
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int i;
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cmpri = ipv6_rpl_srh_calc_cmpri(inhdr, daddr, n);
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cmpre = ipv6_rpl_srh_calc_cmpre(daddr, &inhdr->rpl_segaddr[n]);
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outhdr->nexthdr = inhdr->nexthdr;
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seglen = (n * IPV6_PFXTAIL_LEN(cmpri)) + IPV6_PFXTAIL_LEN(cmpre);
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outhdr->hdrlen = seglen >> 3;
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if (seglen & 0x7) {
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outhdr->hdrlen++;
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outhdr->pad = 8 - (seglen & 0x7);
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} else {
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outhdr->pad = 0;
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}
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outhdr->type = inhdr->type;
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outhdr->segments_left = inhdr->segments_left;
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outhdr->cmpri = cmpri;
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outhdr->cmpre = cmpre;
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for (i = 0; i < n; i++)
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ipv6_rpl_addr_compress(ipv6_rpl_segdata_pos(outhdr, i),
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&inhdr->rpl_segaddr[i], cmpri);
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ipv6_rpl_addr_compress(ipv6_rpl_segdata_pos(outhdr, n),
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&inhdr->rpl_segaddr[n], cmpre);
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}
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