This patch complete reworks the evaluation of 6lowpan dispatch value by
introducing a receive handler mechanism for each dispatch value.
A list of changes:
- Doing uncompression on-the-fly when FRAG1 is received, this require
some special handling for 802.15.4 lltype in generic 6lowpan branch
for setting the payload length correct.
- Fix dispatch mask for fragmentation.
- Add IPv6 dispatch evaluation for FRAG1.
- Add skb_unshare for dispatch which might manipulate the skb data
buffer.
Signed-off-by: Alexander Aring <alex.aring@xxxxxxxxx>
---
include/net/6lowpan.h | 31 ++++--
net/6lowpan/iphc.c | 13 ++-
net/6lowpan/nhc_udp.c | 13 ++-
net/ieee802154/6lowpan/6lowpan_i.h | 12 +++
net/ieee802154/6lowpan/reassembly.c | 126 +++++++++++++++++-------
net/ieee802154/6lowpan/rx.c | 188 ++++++++++++++++++++++++------------
6 files changed, 278 insertions(+), 105 deletions(-)
diff --git a/include/net/6lowpan.h b/include/net/6lowpan.h
index a2f59ec..3509841 100644
--- a/include/net/6lowpan.h
+++ b/include/net/6lowpan.h
@@ -126,13 +126,19 @@
(((a)[6]) == 0xFF) && \
(((a)[7]) == 0xFF))
-#define LOWPAN_DISPATCH_IPV6 0x41 /* 01000001 = 65 */
-#define LOWPAN_DISPATCH_HC1 0x42 /* 01000010 = 66 */
-#define LOWPAN_DISPATCH_IPHC 0x60 /* 011xxxxx = ... */
-#define LOWPAN_DISPATCH_FRAG1 0xc0 /* 11000xxx */
-#define LOWPAN_DISPATCH_FRAGN 0xe0 /* 11100xxx */
+#define LOWPAN_DISPATCH_IPV6 0x41 /* 01000001 = 65 */
+#define LOWPAN_DISPATCH_IPHC 0x60 /* 011xxxxx = ... */
+#define LOWPAN_DISPATCH_IPHC_MASK 0xe0
-#define LOWPAN_DISPATCH_MASK 0xf8 /* 11111000 */
+static inline bool lowpan_is_ipv6(u8 dispatch)
+{
+ return dispatch == LOWPAN_DISPATCH_IPV6;
+}
+
+static inline bool lowpan_is_iphc(u8 dispatch)
+{
+ return (dispatch & LOWPAN_DISPATCH_IPHC_MASK) == LOWPAN_DISPATCH_IPHC;
+}
#define LOWPAN_FRAG_TIMEOUT (HZ * 60) /* time-out 60 sec */
@@ -218,6 +224,19 @@ struct lowpan_priv *lowpan_priv(const struct net_device *dev)
return netdev_priv(dev);
}
+struct lowpan_802154_cb {
+ u16 d_tag;
+ unsigned int d_size;
+ u8 d_offset;
+};
+
+static inline
+struct lowpan_802154_cb *lowpan_802154_cb(const struct sk_buff *skb)
+{
+ BUILD_BUG_ON(sizeof(struct lowpan_802154_cb) > sizeof(skb->cb));
+ return (struct lowpan_802154_cb *)skb->cb;
+}
+
#ifdef DEBUG
/* print data in line */
static inline void raw_dump_inline(const char *caller, char *msg,
diff --git a/net/6lowpan/iphc.c b/net/6lowpan/iphc.c
index 1e0071f..78c8a49 100644
--- a/net/6lowpan/iphc.c
+++ b/net/6lowpan/iphc.c
@@ -366,7 +366,18 @@ lowpan_header_decompress(struct sk_buff *skb, struct net_device *dev,
return err;
}
- hdr.payload_len = htons(skb->len);
+ switch (lowpan_priv(dev)->lltype) {
+ case LOWPAN_LLTYPE_IEEE802154:
+ if (lowpan_802154_cb(skb)->d_size)
+ hdr.payload_len = htons(lowpan_802154_cb(skb)->d_size -
+ sizeof(struct ipv6hdr));
+ else
+ hdr.payload_len = htons(skb->len);
+ break;
+ default:
+ hdr.payload_len = htons(skb->len);
+ break;
+ }
pr_debug("skb headroom size = %d, data length = %d\n",
skb_headroom(skb), skb->len);
diff --git a/net/6lowpan/nhc_udp.c b/net/6lowpan/nhc_udp.c
index c6bcaeb..72d0b57 100644
--- a/net/6lowpan/nhc_udp.c
+++ b/net/6lowpan/nhc_udp.c
@@ -71,7 +71,18 @@ static int udp_uncompress(struct sk_buff *skb, size_t needed)
* here, we obtain the hint from the remaining size of the
* frame
*/
- uh.len = htons(skb->len + sizeof(struct udphdr));
+ switch (lowpan_priv(skb->dev)->lltype) {
+ case LOWPAN_LLTYPE_IEEE802154:
+ if (lowpan_802154_cb(skb)->d_size)
+ uh.len = htons(lowpan_802154_cb(skb)->d_size -
+ sizeof(struct ipv6hdr));
+ else
+ uh.len = htons(skb->len + sizeof(struct udphdr));
+ break;
+ default:
+ uh.len = htons(skb->len + sizeof(struct udphdr));
+ break;
+ }
pr_debug("uncompressed UDP length: src = %d", ntohs(uh.len));
/* replace the compressed UDP head by the uncompressed UDP
diff --git a/net/ieee802154/6lowpan/6lowpan_i.h b/net/ieee802154/6lowpan/6lowpan_i.h
index 9aa7b62..b4e17a7 100644
--- a/net/ieee802154/6lowpan/6lowpan_i.h
+++ b/net/ieee802154/6lowpan/6lowpan_i.h
@@ -7,6 +7,15 @@
#include <net/inet_frag.h>
#include <net/6lowpan.h>
+typedef unsigned __bitwise__ lowpan_rx_result;
+#define RX_CONTINUE ((__force lowpan_rx_result) 0u)
+#define RX_DROP_UNUSABLE ((__force lowpan_rx_result) 1u)
+#define RX_DROP ((__force lowpan_rx_result) 2u)
+#define RX_QUEUED ((__force lowpan_rx_result) 3u)
+
+#define LOWPAN_DISPATCH_FRAG1 0xc0
+#define LOWPAN_DISPATCH_FRAGN 0xe0
+
struct lowpan_create_arg {
u16 tag;
u16 d_size;
@@ -62,4 +71,7 @@ int lowpan_header_create(struct sk_buff *skb, struct net_device *dev,
const void *_saddr, unsigned int len);
netdev_tx_t lowpan_xmit(struct sk_buff *skb, struct net_device *dev);
+int lowpan_iphc_decompress(struct sk_buff *skb);
+lowpan_rx_result lowpan_rx_h_ipv6(struct sk_buff *skb);
+
#endif /* __IEEE802154_6LOWPAN_I_H__ */
diff --git a/net/ieee802154/6lowpan/reassembly.c b/net/ieee802154/6lowpan/reassembly.c
index 0fc3350..fadd985 100644
--- a/net/ieee802154/6lowpan/reassembly.c
+++ b/net/ieee802154/6lowpan/reassembly.c
@@ -32,17 +32,6 @@
static const char lowpan_frags_cache_name[] = "lowpan-frags";
-struct lowpan_frag_info {
- u16 d_tag;
- u16 d_size;
- u8 d_offset;
-};
-
-static struct lowpan_frag_info *lowpan_cb(struct sk_buff *skb)
-{
- return (struct lowpan_frag_info *)skb->cb;
-}
-
static struct inet_frags lowpan_frags;
static int lowpan_frag_reasm(struct lowpan_frag_queue *fq,
@@ -111,7 +100,7 @@ out:
}
static inline struct lowpan_frag_queue *
-fq_find(struct net *net, const struct lowpan_frag_info *frag_info,
+fq_find(struct net *net, const struct lowpan_802154_cb *cb,
const struct ieee802154_addr *src,
const struct ieee802154_addr *dst)
{
@@ -121,12 +110,12 @@ fq_find(struct net *net, const struct lowpan_frag_info *frag_info,
struct netns_ieee802154_lowpan *ieee802154_lowpan =
net_ieee802154_lowpan(net);
- arg.tag = frag_info->d_tag;
- arg.d_size = frag_info->d_size;
+ arg.tag = cb->d_tag;
+ arg.d_size = cb->d_size;
arg.src = src;
arg.dst = dst;
- hash = lowpan_hash_frag(frag_info->d_tag, frag_info->d_size, src, dst);
+ hash = lowpan_hash_frag(cb->d_tag, cb->d_size, src, dst);
q = inet_frag_find(&ieee802154_lowpan->frags,
&lowpan_frags, &arg, hash);
@@ -138,7 +127,7 @@ fq_find(struct net *net, const struct lowpan_frag_info *frag_info,
}
static int lowpan_frag_queue(struct lowpan_frag_queue *fq,
- struct sk_buff *skb, const u8 frag_type)
+ struct sk_buff *skb, u8 frag_type)
{
struct sk_buff *prev, *next;
struct net_device *ldev;
@@ -147,8 +136,8 @@ static int lowpan_frag_queue(struct lowpan_frag_queue *fq,
if (fq->q.flags & INET_FRAG_COMPLETE)
goto err;
- offset = lowpan_cb(skb)->d_offset << 3;
- end = lowpan_cb(skb)->d_size;
+ offset = lowpan_802154_cb(skb)->d_offset << 3;
+ end = lowpan_802154_cb(skb)->d_size;
/* Is this the final fragment? */
if (offset + skb->len == end) {
@@ -174,13 +163,16 @@ static int lowpan_frag_queue(struct lowpan_frag_queue *fq,
* this fragment, right?
*/
prev = fq->q.fragments_tail;
- if (!prev || lowpan_cb(prev)->d_offset < lowpan_cb(skb)->d_offset) {
+ if (!prev ||
+ lowpan_802154_cb(prev)->d_offset <
+ lowpan_802154_cb(skb)->d_offset) {
next = NULL;
goto found;
}
prev = NULL;
for (next = fq->q.fragments; next != NULL; next = next->next) {
- if (lowpan_cb(next)->d_offset >= lowpan_cb(skb)->d_offset)
+ if (lowpan_802154_cb(next)->d_offset >=
+ lowpan_802154_cb(skb)->d_offset)
break; /* bingo! */
prev = next;
}
@@ -201,8 +193,7 @@ found:
fq->q.stamp = skb->tstamp;
if (frag_type == LOWPAN_DISPATCH_FRAG1) {
- /* Calculate uncomp. 6lowpan header to estimate full size */
- fq->q.meat += lowpan_uncompress_size(skb, NULL);
+ fq->q.meat += skb->len;
fq->q.flags |= INET_FRAG_FIRST_IN;
} else {
fq->q.meat += skb->len;
@@ -325,8 +316,59 @@ out_oom:
return -1;
}
-static int lowpan_get_frag_info(struct sk_buff *skb, const u8 frag_type,
- struct lowpan_frag_info *frag_info)
+int lowpan_frag_rx_handlers_result(struct sk_buff *skb, lowpan_rx_result res)
+{
+ switch (res) {
+ case RX_QUEUED:
+ return NET_RX_SUCCESS;
+ case RX_CONTINUE:
+ /* nobody cared about this packet */
+ net_warn_ratelimited("%s: received unknown dispatch\n",
+ __func__);
+
+ /* fall-through */
+ default:
+ /* all others failure */
+ return NET_RX_DROP;
+ }
+}
+
+static lowpan_rx_result lowpan_frag_rx_h_iphc(struct sk_buff *skb)
+{
+ int ret;
+
+ if (!lowpan_is_iphc(*skb_network_header(skb)))
+ return RX_CONTINUE;
+
+ ret = lowpan_iphc_decompress(skb);
+ if (ret < 0)
+ return RX_DROP;
+
+ return RX_QUEUED;
+}
+
+static int lowpan_invoke_frag_rx_handlers(struct sk_buff *skb)
+{
+ lowpan_rx_result res;
+
+#define CALL_RXH(rxh) \
+ do { \
+ res = rxh(skb); \
+ if (res != RX_CONTINUE) \
+ goto rxh_next; \
+ } while (0)
+
+ /* likely at first */
+ CALL_RXH(lowpan_frag_rx_h_iphc);
+ CALL_RXH(lowpan_rx_h_ipv6);
+
+rxh_next:
+ return lowpan_frag_rx_handlers_result(skb, res);
+#undef CALL_RXH
+}
+
+static int lowpan_get_cb(struct sk_buff *skb, u8 frag_type,
+ struct lowpan_802154_cb *cb)
{
bool fail;
u8 pattern = 0, low = 0;
@@ -334,15 +376,19 @@ static int lowpan_get_frag_info(struct sk_buff *skb, const u8 frag_type,
fail = lowpan_fetch_skb(skb, &pattern, 1);
fail |= lowpan_fetch_skb(skb, &low, 1);
- frag_info->d_size = (pattern & 7) << 8 | low;
+ cb->d_size = (pattern & 7) << 8 | low;
fail |= lowpan_fetch_skb(skb, &d_tag, 2);
- frag_info->d_tag = ntohs(d_tag);
+ cb->d_tag = ntohs(d_tag);
if (frag_type == LOWPAN_DISPATCH_FRAGN) {
- fail |= lowpan_fetch_skb(skb, &frag_info->d_offset, 1);
+ fail |= lowpan_fetch_skb(skb, &cb->d_offset, 1);
} else {
skb_reset_network_header(skb);
- frag_info->d_offset = 0;
+ cb->d_offset = 0;
+ /* check if datagram_size has ipv6hdr on FRAG1 */
+ fail |= cb->d_size < sizeof(struct ipv6hdr);
+ /* check if we can dereference the dispatch value */
+ fail |= !skb->len;
}
if (unlikely(fail))
@@ -351,27 +397,35 @@ static int lowpan_get_frag_info(struct sk_buff *skb, const u8 frag_type,
return 0;
}
-int lowpan_frag_rcv(struct sk_buff *skb, const u8 frag_type)
+int lowpan_frag_rcv(struct sk_buff *skb, u8 frag_type)
{
struct lowpan_frag_queue *fq;
struct net *net = dev_net(skb->dev);
- struct lowpan_frag_info *frag_info = lowpan_cb(skb);
- struct ieee802154_addr source, dest;
+ struct lowpan_802154_cb *cb = lowpan_802154_cb(skb);
+ struct ieee802154_hdr hdr;
int err;
- source = mac_cb(skb)->source;
- dest = mac_cb(skb)->dest;
+ if (ieee802154_hdr_peek_addrs(skb, &hdr) < 0)
+ goto err;
- err = lowpan_get_frag_info(skb, frag_type, frag_info);
+ err = lowpan_get_cb(skb, frag_type, cb);
if (err < 0)
goto err;
- if (frag_info->d_size > IPV6_MIN_MTU) {
+ if (frag_type == LOWPAN_DISPATCH_FRAG1) {
+ lowpan_rx_result res;
+
+ res = lowpan_invoke_frag_rx_handlers(skb);
+ if (res == NET_RX_DROP)
+ goto err;
+ }
+
+ if (cb->d_size > IPV6_MIN_MTU) {
net_warn_ratelimited("lowpan_frag_rcv: datagram size exceeds MTU\n");
goto err;
}
- fq = fq_find(net, frag_info, &source, &dest);
+ fq = fq_find(net, cb, &hdr.source, &hdr.dest);
if (fq != NULL) {
int ret;
diff --git a/net/ieee802154/6lowpan/rx.c b/net/ieee802154/6lowpan/rx.c
index f9cb70b..2adc92a 100644
--- a/net/ieee802154/6lowpan/rx.c
+++ b/net/ieee802154/6lowpan/rx.c
@@ -15,8 +15,9 @@
#include "6lowpan_i.h"
-static int lowpan_give_skb_to_device(struct sk_buff *skb,
- struct net_device *wdev)
+#define LOWPAN_DISPATCH_FRAG_MASK 0xf8
+
+static int lowpan_give_skb_to_device(struct sk_buff *skb)
{
skb->protocol = htons(ETH_P_IPV6);
skb->pkt_type = PACKET_HOST;
@@ -24,21 +25,77 @@ static int lowpan_give_skb_to_device(struct sk_buff *skb,
return netif_rx(skb);
}
-static int
-iphc_decompress(struct sk_buff *skb, const struct ieee802154_hdr *hdr)
+int lowpan_rx_handlers_result(struct sk_buff *skb, lowpan_rx_result res)
+{
+ switch (res) {
+ case RX_CONTINUE:
+ /* nobody cared about this packet */
+ net_warn_ratelimited("%s: received unknown dispatch\n",
+ __func__);
+
+ /* fall-through */
+ case RX_DROP_UNUSABLE:
+ kfree_skb(skb);
+
+ /* fall-through */
+ case RX_DROP:
+ return NET_RX_DROP;
+ case RX_QUEUED:
+ return lowpan_give_skb_to_device(skb);
+ default:
+ break;
+ }
+
+ return NET_RX_DROP;
+}
+
+static inline bool lowpan_is_frag1(u8 dispatch)
+{
+ return (dispatch & LOWPAN_DISPATCH_FRAG_MASK) == LOWPAN_DISPATCH_FRAG1;
+}
+
+static inline bool lowpan_is_fragn(u8 dispatch)
+{
+ return (dispatch & LOWPAN_DISPATCH_FRAG_MASK) == LOWPAN_DISPATCH_FRAGN;
+}
+
+static lowpan_rx_result lowpan_rx_h_frag(struct sk_buff *skb)
+{
+ int ret;
+
+ if (!(lowpan_is_frag1(*skb_network_header(skb)) ||
+ lowpan_is_fragn(*skb_network_header(skb))))
+ return RX_CONTINUE;
+
+ ret = lowpan_frag_rcv(skb, *skb_network_header(skb) &
+ LOWPAN_DISPATCH_FRAG_MASK);
+ if (ret == 1)
+ return RX_QUEUED;
+
+ /* Packet is freed by lowpan_frag_rcv on error or put into the frag
+ * bucket.
+ */
+ return RX_DROP;
+}
+
+int lowpan_iphc_decompress(struct sk_buff *skb)
{
- u8 iphc0, iphc1;
struct ieee802154_addr_sa sa, da;
+ struct ieee802154_hdr hdr;
+ u8 iphc0, iphc1;
void *sap, *dap;
+ if (ieee802154_hdr_peek_addrs(skb, &hdr) < 0)
+ return -EINVAL;
+
raw_dump_table(__func__, "raw skb data dump", skb->data, skb->len);
if (lowpan_fetch_skb_u8(skb, &iphc0) ||
lowpan_fetch_skb_u8(skb, &iphc1))
return -EINVAL;
- ieee802154_addr_to_sa(&sa, &hdr->source);
- ieee802154_addr_to_sa(&da, &hdr->dest);
+ ieee802154_addr_to_sa(&sa, &hdr.source);
+ ieee802154_addr_to_sa(&da, &hdr.dest);
if (sa.addr_type == IEEE802154_ADDR_SHORT)
sap = &sa.short_addr;
@@ -55,78 +112,87 @@ iphc_decompress(struct sk_buff *skb, const struct ieee802154_hdr *hdr)
IEEE802154_ADDR_LEN, iphc0, iphc1);
}
+static lowpan_rx_result lowpan_rx_h_iphc(struct sk_buff *skb)
+{
+ int ret;
+
+ if (!lowpan_is_iphc(*skb_network_header(skb)))
+ return RX_CONTINUE;
+
+ /* Setting datagram_offset to zero indicates non frag handling
+ * while doing lowpan_header_decompress.
+ */
+ lowpan_802154_cb(skb)->d_size = 0;
+
+ ret = lowpan_iphc_decompress(skb);
+ if (ret < 0)
+ return RX_DROP_UNUSABLE;
+
+ return RX_QUEUED;
+}
+
+lowpan_rx_result lowpan_rx_h_ipv6(struct sk_buff *skb)
+{
+ if (!lowpan_is_ipv6(*skb_network_header(skb)))
+ return RX_CONTINUE;
+
+ /* Pull off the 1-byte of 6lowpan header. */
+ skb_pull(skb, 1);
+ return RX_QUEUED;
+}
+
+static int lowpan_invoke_rx_handlers(struct sk_buff *skb)
+{
+ lowpan_rx_result res;
+
+#define CALL_RXH(rxh) \
+ do { \
+ res = rxh(skb); \
+ if (res != RX_CONTINUE) \
+ goto rxh_next; \
+ } while (0)
+
+ /* likely at first */
+ CALL_RXH(lowpan_rx_h_iphc);
+ CALL_RXH(lowpan_rx_h_frag);
+ CALL_RXH(lowpan_rx_h_ipv6);
+
+rxh_next:
+ return lowpan_rx_handlers_result(skb, res);
+#undef CALL_RXH
+}
+
static int lowpan_rcv(struct sk_buff *skb, struct net_device *wdev,
struct packet_type *pt, struct net_device *orig_wdev)
{
- struct ieee802154_hdr hdr;
struct net_device *ldev;
- int ret;
if (wdev->type != ARPHRD_IEEE802154 ||
skb->pkt_type == PACKET_OTHERHOST)
- goto drop;
+ return NET_RX_DROP;
ldev = wdev->ieee802154_ptr->lowpan_dev;
if (!ldev || !netif_running(ldev))
- goto drop;
+ return NET_RX_DROP;
/* Replacing skb->dev and followed rx handlers will manipulate skb. */
skb = skb_share_check(skb, GFP_ATOMIC);
if (!skb)
- goto drop;
+ return NET_RX_DROP;
skb->dev = ldev;
- if (ieee802154_hdr_peek_addrs(skb, &hdr) < 0)
- goto drop_skb;
-
- /* check that it's our buffer */
- if (skb->data[0] == LOWPAN_DISPATCH_IPV6) {
- /* Pull off the 1-byte of 6lowpan header. */
- skb_pull(skb, 1);
- return lowpan_give_skb_to_device(skb, wdev);
- } else {
- switch (skb->data[0] & 0xe0) {
- case LOWPAN_DISPATCH_IPHC: /* ipv6 datagram */
- ret = iphc_decompress(skb, &hdr);
- if (ret < 0)
- goto drop_skb;
-
- return lowpan_give_skb_to_device(skb, wdev);
- case LOWPAN_DISPATCH_FRAG1: /* first fragment header */
- ret = lowpan_frag_rcv(skb, LOWPAN_DISPATCH_FRAG1);
- if (ret == 1) {
- ret = iphc_decompress(skb, &hdr);
- if (ret < 0)
- goto drop_skb;
-
- return lowpan_give_skb_to_device(skb, wdev);
- } else if (ret == -1) {
- return NET_RX_DROP;
- } else {
- return NET_RX_SUCCESS;
- }
- case LOWPAN_DISPATCH_FRAGN: /* next fragments headers */
- ret = lowpan_frag_rcv(skb, LOWPAN_DISPATCH_FRAGN);
- if (ret == 1) {
- ret = iphc_decompress(skb, &hdr);
- if (ret < 0)
- goto drop_skb;
-
- return lowpan_give_skb_to_device(skb, wdev);
- } else if (ret == -1) {
- return NET_RX_DROP;
- } else {
- return NET_RX_SUCCESS;
- }
- default:
- break;
- }
+ /* When receive frag1 it's likely that we manipulate the buffer.
+ * When recevie iphc we manipulate the data buffer. So we need
+ * to unshare the buffer.
+ */
+ if (lowpan_is_frag1(*skb_network_header(skb)) ||
+ lowpan_is_iphc(*skb_network_header(skb))) {
+ skb = skb_unshare(skb, GFP_ATOMIC);
+ if (!skb)
+ return RX_DROP;
}
-drop_skb:
- kfree_skb(skb);
-drop:
- return NET_RX_DROP;
+ return lowpan_invoke_rx_handlers(skb);
}
static struct packet_type lowpan_packet_type = {
--
2.5.0
--
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