/* * Copyright (C) 2014 Fraunhofer ITWM * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 * as published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * Written by: * Phoebe Buckheister <phoebe.buckheister@itwm.fraunhofer.de> */ #include <linux/ieee802154.h> #include <net/mac802154.h> #include <net/ieee802154_netdev.h> static int ieee802154_hdr_push_addr(u8 *buf, const struct ieee802154_addr *addr, bool omit_pan) { int pos = 0; if (addr->mode == IEEE802154_ADDR_NONE) return 0; if (!omit_pan) { memcpy(buf + pos, &addr->pan_id, 2); pos += 2; } switch (addr->mode) { case IEEE802154_ADDR_SHORT: memcpy(buf + pos, &addr->short_addr, 2); pos += 2; break; case IEEE802154_ADDR_LONG: memcpy(buf + pos, &addr->extended_addr, IEEE802154_ADDR_LEN); pos += IEEE802154_ADDR_LEN; break; default: return -EINVAL; } return pos; } static int ieee802154_hdr_push_sechdr(u8 *buf, const struct ieee802154_sechdr *hdr) { int pos = 5; memcpy(buf, hdr, 1); memcpy(buf + 1, &hdr->frame_counter, 4); switch (hdr->key_id_mode) { case IEEE802154_SCF_KEY_IMPLICIT: return pos; case IEEE802154_SCF_KEY_INDEX: break; case IEEE802154_SCF_KEY_SHORT_INDEX: memcpy(buf + pos, &hdr->short_src, 4); pos += 4; break; case IEEE802154_SCF_KEY_HW_INDEX: memcpy(buf + pos, &hdr->extended_src, IEEE802154_ADDR_LEN); pos += IEEE802154_ADDR_LEN; break; } buf[pos++] = hdr->key_id; return pos; } int ieee802154_hdr_push(struct sk_buff *skb, struct ieee802154_hdr *hdr) { u8 buf[IEEE802154_MAX_HEADER_LEN]; int pos = 2; int rc; struct ieee802154_hdr_fc *fc = &hdr->fc; buf[pos++] = hdr->seq; fc->dest_addr_mode = hdr->dest.mode; rc = ieee802154_hdr_push_addr(buf + pos, &hdr->dest, false); if (rc < 0) return -EINVAL; pos += rc; fc->source_addr_mode = hdr->source.mode; if (hdr->source.pan_id == hdr->dest.pan_id && hdr->dest.mode != IEEE802154_ADDR_NONE) fc->intra_pan = true; rc = ieee802154_hdr_push_addr(buf + pos, &hdr->source, fc->intra_pan); if (rc < 0) return -EINVAL; pos += rc; if (fc->security_enabled) { fc->version = 1; rc = ieee802154_hdr_push_sechdr(buf + pos, &hdr->sec); if (rc < 0) return -EINVAL; pos += rc; } memcpy(buf, fc, 2); memcpy(skb_push(skb, pos), buf, pos); return pos; } EXPORT_SYMBOL_GPL(ieee802154_hdr_push); static int ieee802154_hdr_get_addr(const u8 *buf, int mode, bool omit_pan, struct ieee802154_addr *addr) { int pos = 0; addr->mode = mode; if (mode == IEEE802154_ADDR_NONE) return 0; if (!omit_pan) { memcpy(&addr->pan_id, buf + pos, 2); pos += 2; } if (mode == IEEE802154_ADDR_SHORT) { memcpy(&addr->short_addr, buf + pos, 2); return pos + 2; } else { memcpy(&addr->extended_addr, buf + pos, IEEE802154_ADDR_LEN); return pos + IEEE802154_ADDR_LEN; } } static int ieee802154_hdr_addr_len(int mode, bool omit_pan) { int pan_len = omit_pan ? 0 : 2; switch (mode) { case IEEE802154_ADDR_NONE: return 0; case IEEE802154_ADDR_SHORT: return 2 + pan_len; case IEEE802154_ADDR_LONG: return IEEE802154_ADDR_LEN + pan_len; default: return -EINVAL; } } static int ieee802154_hdr_get_sechdr(const u8 *buf, struct ieee802154_sechdr *hdr) { int pos = 5; memcpy(hdr, buf, 1); memcpy(&hdr->frame_counter, buf + 1, 4); switch (hdr->key_id_mode) { case IEEE802154_SCF_KEY_IMPLICIT: return pos; case IEEE802154_SCF_KEY_INDEX: break; case IEEE802154_SCF_KEY_SHORT_INDEX: memcpy(&hdr->short_src, buf + pos, 4); pos += 4; break; case IEEE802154_SCF_KEY_HW_INDEX: memcpy(&hdr->extended_src, buf + pos, IEEE802154_ADDR_LEN); pos += IEEE802154_ADDR_LEN; break; } hdr->key_id = buf[pos++]; return pos; } static int ieee802154_sechdr_lengths[4] = { [IEEE802154_SCF_KEY_IMPLICIT] = 5, [IEEE802154_SCF_KEY_INDEX] = 6, [IEEE802154_SCF_KEY_SHORT_INDEX] = 10, [IEEE802154_SCF_KEY_HW_INDEX] = 14, }; static int ieee802154_hdr_sechdr_len(u8 sc) { return ieee802154_sechdr_lengths[IEEE802154_SCF_KEY_ID_MODE(sc)]; } static int ieee802154_hdr_minlen(const struct ieee802154_hdr *hdr) { int dlen, slen; dlen = ieee802154_hdr_addr_len(hdr->fc.dest_addr_mode, false); slen = ieee802154_hdr_addr_len(hdr->fc.source_addr_mode, hdr->fc.intra_pan); if (slen < 0 || dlen < 0) return -EINVAL; return 3 + dlen + slen + hdr->fc.security_enabled; } static int ieee802154_hdr_get_addrs(const u8 *buf, struct ieee802154_hdr *hdr) { int pos = 0; pos += ieee802154_hdr_get_addr(buf + pos, hdr->fc.dest_addr_mode, false, &hdr->dest); pos += ieee802154_hdr_get_addr(buf + pos, hdr->fc.source_addr_mode, hdr->fc.intra_pan, &hdr->source); if (hdr->fc.intra_pan) hdr->source.pan_id = hdr->dest.pan_id; return pos; } int ieee802154_hdr_pull(struct sk_buff *skb, struct ieee802154_hdr *hdr) { int pos = 3, rc; if (!pskb_may_pull(skb, 3)) return -EINVAL; memcpy(hdr, skb->data, 3); rc = ieee802154_hdr_minlen(hdr); if (rc < 0 || !pskb_may_pull(skb, rc)) return -EINVAL; pos += ieee802154_hdr_get_addrs(skb->data + pos, hdr); if (hdr->fc.security_enabled) { int want = pos + ieee802154_hdr_sechdr_len(skb->data[pos]); if (!pskb_may_pull(skb, want)) return -EINVAL; pos += ieee802154_hdr_get_sechdr(skb->data + pos, &hdr->sec); } skb_pull(skb, pos); return pos; } EXPORT_SYMBOL_GPL(ieee802154_hdr_pull); int ieee802154_hdr_peek_addrs(const struct sk_buff *skb, struct ieee802154_hdr *hdr) { const u8 *buf = skb_mac_header(skb); int pos = 3, rc; if (buf + 3 > skb_tail_pointer(skb)) return -EINVAL; memcpy(hdr, buf, 3); rc = ieee802154_hdr_minlen(hdr); if (rc < 0 || buf + rc > skb_tail_pointer(skb)) return -EINVAL; pos += ieee802154_hdr_get_addrs(buf + pos, hdr); return pos; } EXPORT_SYMBOL_GPL(ieee802154_hdr_peek_addrs); int ieee802154_hdr_peek(const struct sk_buff *skb, struct ieee802154_hdr *hdr) { const u8 *buf = skb_mac_header(skb); int pos; pos = ieee802154_hdr_peek_addrs(skb, hdr); if (pos < 0) return -EINVAL; if (hdr->fc.security_enabled) { u8 key_id_mode = IEEE802154_SCF_KEY_ID_MODE(*(buf + pos)); int want = pos + ieee802154_sechdr_lengths[key_id_mode]; if (buf + want > skb_tail_pointer(skb)) return -EINVAL; pos += ieee802154_hdr_get_sechdr(buf + pos, &hdr->sec); } return pos; } EXPORT_SYMBOL_GPL(ieee802154_hdr_peek); int ieee802154_max_payload(const struct ieee802154_hdr *hdr) { int hlen = ieee802154_hdr_minlen(hdr); if (hdr->fc.security_enabled) { hlen += ieee802154_sechdr_lengths[hdr->sec.key_id_mode] - 1; hlen += ieee802154_sechdr_authtag_len(&hdr->sec); } return IEEE802154_MTU - hlen - IEEE802154_MFR_SIZE; } EXPORT_SYMBOL_GPL(ieee802154_max_payload);