// SPDX-License-Identifier: GPL-2.0-only /** * Authors: * (C) 2020 Alexander Aring <alex.aring@gmail.com> */ #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); }