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-rw-r--r--net/ipv6/rpl.c125
1 files changed, 125 insertions, 0 deletions
diff --git a/net/ipv6/rpl.c b/net/ipv6/rpl.c
new file mode 100644
index 000000000..d1876f192
--- /dev/null
+++ b/net/ipv6/rpl.c
@@ -0,0 +1,125 @@
+// 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 sizeof(struct ipv6_rpl_sr_hdr) + (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);
+}