ieee802154: add header structs with endiannes and operations
This patch provides a set of structures to represent 802.15.4 MAC headers, and a set of operations to push/pull/peek these structs from skbs. We cannot simply pointer-cast the skb MAC header pointer to these structs, because 802.15.4 headers are wildly variable - depending on the first three bytes, virtually all other fields of the header may be present or not, and be present with different lengths. The new header creation/parsing routines also support 802.15.4 security headers, which are currently not supported by the mac802154 implementation of the protocol. Signed-off-by: Phoebe Buckheister <phoebe.buckheister@itwm.fraunhofer.de> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Phoebe Buckheister
committed by
David S. Miller
David S. Miller
parent
b70ab2e87f
commit
94b4f6c21c
287
net/ieee802154/header_ops.c
Normal file
287
net/ieee802154/header_ops.c
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@@ -0,0 +1,287 @@
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/*
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* Copyright (C) 2014 Fraunhofer ITWM
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2
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* as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* Written by:
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* Phoebe Buckheister <phoebe.buckheister@itwm.fraunhofer.de>
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*/
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#include <net/mac802154.h>
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#include <net/ieee802154.h>
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#include <net/ieee802154_netdev.h>
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static int
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ieee802154_hdr_push_addr(u8 *buf, const struct ieee802154_addr *addr,
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bool omit_pan)
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{
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int pos = 0;
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if (addr->mode == IEEE802154_ADDR_NONE)
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return 0;
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if (!omit_pan) {
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memcpy(buf + pos, &addr->pan_id, 2);
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pos += 2;
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}
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switch (addr->mode) {
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case IEEE802154_ADDR_SHORT:
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memcpy(buf + pos, &addr->short_addr, 2);
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pos += 2;
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break;
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case IEEE802154_ADDR_LONG:
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memcpy(buf + pos, &addr->extended_addr, IEEE802154_ADDR_LEN);
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pos += IEEE802154_ADDR_LEN;
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break;
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default:
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return -EINVAL;
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}
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return pos;
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}
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static int
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ieee802154_hdr_push_sechdr(u8 *buf, const struct ieee802154_sechdr *hdr)
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{
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int pos = 5;
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memcpy(buf, hdr, 1);
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memcpy(buf + 1, &hdr->frame_counter, 4);
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switch (hdr->key_id_mode) {
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case IEEE802154_SCF_KEY_IMPLICIT:
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return pos;
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case IEEE802154_SCF_KEY_INDEX:
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break;
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case IEEE802154_SCF_KEY_SHORT_INDEX:
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memcpy(buf + pos, &hdr->short_src, 4);
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pos += 4;
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break;
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case IEEE802154_SCF_KEY_HW_INDEX:
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memcpy(buf + pos, &hdr->extended_src, IEEE802154_ADDR_LEN);
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pos += IEEE802154_ADDR_LEN;
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break;
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}
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buf[pos++] = hdr->key_id;
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return pos;
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}
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int
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ieee802154_hdr_push(struct sk_buff *skb, const struct ieee802154_hdr *hdr)
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{
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u8 buf[MAC802154_FRAME_HARD_HEADER_LEN];
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int pos = 2;
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int rc;
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struct ieee802154_hdr_fc fc = hdr->fc;
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buf[pos++] = hdr->seq;
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fc.dest_addr_mode = hdr->dest.mode;
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rc = ieee802154_hdr_push_addr(buf + pos, &hdr->dest, false);
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if (rc < 0)
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return -EINVAL;
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pos += rc;
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fc.source_addr_mode = hdr->source.mode;
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if (hdr->source.pan_id == hdr->dest.pan_id &&
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hdr->dest.mode != IEEE802154_ADDR_NONE)
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fc.intra_pan = true;
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rc = ieee802154_hdr_push_addr(buf + pos, &hdr->source, fc.intra_pan);
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if (rc < 0)
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return -EINVAL;
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pos += rc;
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if (fc.security_enabled) {
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fc.version = 1;
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rc = ieee802154_hdr_push_sechdr(buf + pos, &hdr->sec);
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if (rc < 0)
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return -EINVAL;
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pos += rc;
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}
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memcpy(buf, &fc, 2);
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memcpy(skb_push(skb, pos), buf, pos);
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return pos;
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}
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EXPORT_SYMBOL_GPL(ieee802154_hdr_push);
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static int
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ieee802154_hdr_get_addr(const u8 *buf, int mode, bool omit_pan,
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struct ieee802154_addr *addr)
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{
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int pos = 0;
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addr->mode = mode;
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if (mode == IEEE802154_ADDR_NONE)
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return 0;
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if (!omit_pan) {
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memcpy(&addr->pan_id, buf + pos, 2);
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pos += 2;
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}
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if (mode == IEEE802154_ADDR_SHORT) {
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memcpy(&addr->short_addr, buf + pos, 2);
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return pos + 2;
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} else {
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memcpy(&addr->extended_addr, buf + pos, IEEE802154_ADDR_LEN);
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return pos + IEEE802154_ADDR_LEN;
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}
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}
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static int ieee802154_hdr_addr_len(int mode, bool omit_pan)
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{
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int pan_len = omit_pan ? 0 : 2;
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switch (mode) {
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case IEEE802154_ADDR_NONE: return 0;
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case IEEE802154_ADDR_SHORT: return 2 + pan_len;
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case IEEE802154_ADDR_LONG: return IEEE802154_ADDR_LEN + pan_len;
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default: return -EINVAL;
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}
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}
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static int
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ieee802154_hdr_get_sechdr(const u8 *buf, struct ieee802154_sechdr *hdr)
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{
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int pos = 5;
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memcpy(hdr, buf, 1);
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memcpy(&hdr->frame_counter, buf + 1, 4);
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switch (hdr->key_id_mode) {
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case IEEE802154_SCF_KEY_IMPLICIT:
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return pos;
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case IEEE802154_SCF_KEY_INDEX:
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break;
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case IEEE802154_SCF_KEY_SHORT_INDEX:
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memcpy(&hdr->short_src, buf + pos, 4);
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pos += 4;
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break;
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case IEEE802154_SCF_KEY_HW_INDEX:
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memcpy(&hdr->extended_src, buf + pos, IEEE802154_ADDR_LEN);
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pos += IEEE802154_ADDR_LEN;
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break;
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}
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hdr->key_id = buf[pos++];
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return pos;
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}
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static int ieee802154_hdr_sechdr_len(u8 sc)
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{
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switch (IEEE802154_SCF_KEY_ID_MODE(sc)) {
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case IEEE802154_SCF_KEY_IMPLICIT: return 5;
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case IEEE802154_SCF_KEY_INDEX: return 6;
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case IEEE802154_SCF_KEY_SHORT_INDEX: return 10;
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case IEEE802154_SCF_KEY_HW_INDEX: return 14;
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default: return -EINVAL;
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}
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}
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static int ieee802154_hdr_minlen(const struct ieee802154_hdr *hdr)
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{
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int dlen, slen;
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dlen = ieee802154_hdr_addr_len(hdr->fc.dest_addr_mode, false);
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slen = ieee802154_hdr_addr_len(hdr->fc.source_addr_mode,
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hdr->fc.intra_pan);
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if (slen < 0 || dlen < 0)
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return -EINVAL;
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return 3 + dlen + slen + hdr->fc.security_enabled;
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}
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static int
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ieee802154_hdr_get_addrs(const u8 *buf, struct ieee802154_hdr *hdr)
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{
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int pos = 0;
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pos += ieee802154_hdr_get_addr(buf + pos, hdr->fc.dest_addr_mode,
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false, &hdr->dest);
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pos += ieee802154_hdr_get_addr(buf + pos, hdr->fc.source_addr_mode,
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hdr->fc.intra_pan, &hdr->source);
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if (hdr->fc.intra_pan)
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hdr->source.pan_id = hdr->dest.pan_id;
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return pos;
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}
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int
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ieee802154_hdr_pull(struct sk_buff *skb, struct ieee802154_hdr *hdr)
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{
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int pos = 3, rc;
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if (!pskb_may_pull(skb, 3))
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return -EINVAL;
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memcpy(hdr, skb->data, 3);
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rc = ieee802154_hdr_minlen(hdr);
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if (rc < 0 || !pskb_may_pull(skb, rc))
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return -EINVAL;
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pos += ieee802154_hdr_get_addrs(skb->data + pos, hdr);
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if (hdr->fc.security_enabled) {
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int want = pos + ieee802154_hdr_sechdr_len(skb->data[pos]);
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if (!pskb_may_pull(skb, want))
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return -EINVAL;
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pos += ieee802154_hdr_get_sechdr(skb->data + pos, &hdr->sec);
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}
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skb_pull(skb, pos);
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return pos;
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}
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EXPORT_SYMBOL_GPL(ieee802154_hdr_pull);
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int
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ieee802154_hdr_peek_addrs(const struct sk_buff *skb, struct ieee802154_hdr *hdr)
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{
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const u8 *buf = skb_mac_header(skb);
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int pos = 3, rc;
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if (buf + 3 > skb_tail_pointer(skb))
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return -EINVAL;
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memcpy(hdr, buf, 3);
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rc = ieee802154_hdr_minlen(hdr);
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if (rc < 0 || buf + rc > skb_tail_pointer(skb))
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return -EINVAL;
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pos += ieee802154_hdr_get_addrs(buf + pos, hdr);
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return pos;
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}
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EXPORT_SYMBOL_GPL(ieee802154_hdr_peek_addrs);
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