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>
diff --git a/net/ieee802154/Makefile b/net/ieee802154/Makefile
index 78b1fa2..bf1b514 100644
--- a/net/ieee802154/Makefile
+++ b/net/ieee802154/Makefile
@@ -3,7 +3,8 @@
obj-$(CONFIG_6LOWPAN_IPHC) += 6lowpan_iphc.o
6lowpan-y := 6lowpan_rtnl.o reassembly.o
-ieee802154-y := netlink.o nl-mac.o nl-phy.o nl_policy.o wpan-class.o
+ieee802154-y := netlink.o nl-mac.o nl-phy.o nl_policy.o wpan-class.o \
+ header_ops.o
af_802154-y := af_ieee802154.o raw.o dgram.o
ccflags-y += -D__CHECK_ENDIAN__
diff --git a/net/ieee802154/header_ops.c b/net/ieee802154/header_ops.c
new file mode 100644
index 0000000..bed42a4
--- /dev/null
+++ b/net/ieee802154/header_ops.c
@@ -0,0 +1,287 @@
+/*
+ * 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 <net/mac802154.h>
+#include <net/ieee802154.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, const struct ieee802154_hdr *hdr)
+{
+ u8 buf[MAC802154_FRAME_HARD_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_hdr_sechdr_len(u8 sc)
+{
+ switch (IEEE802154_SCF_KEY_ID_MODE(sc)) {
+ case IEEE802154_SCF_KEY_IMPLICIT: return 5;
+ case IEEE802154_SCF_KEY_INDEX: return 6;
+ case IEEE802154_SCF_KEY_SHORT_INDEX: return 10;
+ case IEEE802154_SCF_KEY_HW_INDEX: return 14;
+ default: return -EINVAL;
+ }
+}
+
+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);