Hi,
On Mon, Jul 13, 2015 at 01:50:31PM +0200, Lukasz Duda wrote:
> The patch adds stateful compression (context ids based compression) to
> the 6lowpan module [RFC6282].
>
> Stateful Compression users allocate context tables through the functions
> in the context.c using public APIs declared in 6lowpan.h. The context.c
> is extending the 6lowpan module and not created as a separate module.
>
> A debugfs entry for maintaining the context tables is implemented
> (/sys/kernel/debug/6lowpan/context).
>
> Example usage of the 6lowpan debugfs interface:
>
> echo "<CMD> <IFACE> <CID> <CID_PREFIX> <CID_PREFIX_LENGTH>
> <COMPRESSION_ENABLE_FLAG>" > /sys/kernel/debug/6lowpan/context
>
> Examples:
>
> echo "add bt0 3 2001:db8:: 64 1" > /sys/kernel/debug/6lowpan/context
>
> echo "remove bt0 3" > /sys/kernel/debug/6lowpan/context
>
> cat /sys/kernel/debug/6lowpan/context
>
> e.g.
> Context table of interface bt0
>
> CID Prefix Len CF
> 3 2001:db8:: 64 1
> 4 2001:db8::1 128 1
>
I tried to test it and I got a:
[ 132.092412] =================================
[ 132.096976] [ INFO: inconsistent lock state ]
[ 132.101545] 4.1.0-268283-gca74796 #9 Tainted: G W
[ 132.107650] ---------------------------------
[ 132.112214] inconsistent {IN-SOFTIRQ-W} -> {SOFTIRQ-ON-W} usage.
[ 132.118506] sh/1254 [HC0[0]:SC0[0]:HE1:SE1] takes:
[ 132.123525] (module_lock){+.?...}, at: [<bf07e6e4>] get_table+0x14/0x5c [6lowpan]
[ 132.131536] {IN-SOFTIRQ-W} state was registered at:
[ 132.136645] [<c06c1d30>] _raw_spin_lock+0x30/0x40
[ 132.141785] [<bf07e6e4>] get_table+0x14/0x5c [6lowpan]
[ 132.147372] [<bf07f418>] lowpan_context_compress+0x24/0x1d8 [6lowpan]
[ 132.154324] [<bf07d36c>] lowpan_header_compress+0x68/0x6c0 [6lowpan]
[ 132.161175] [<bf0a1648>] lowpan_header+0x84/0x250 [ieee802154_6lowpan]
[ 132.168220] [<bf0a1a98>] lowpan_xmit+0x68/0x344 [ieee802154_6lowpan]
[ 132.175070] [<c04fdeb8>] dev_hard_start_xmit+0x2a8/0x498
[ 132.180829] [<c04fe84c>] __dev_queue_xmit+0x660/0x798
[ 132.186315] [<bf0024c0>] ip6_finish_output2+0x320/0xbb0 [ipv6]
[ 132.192845] [<bf00805c>] ip6_output+0x6c/0x2c8 [ipv6]
[ 132.198412] [<bf02e880>] mld_sendpack+0x32c/0x89c [ipv6]
[ 132.204318] [<bf02f678>] mld_ifc_timer_expire+0x1d4/0x304 [ipv6]
[ 132.210929] [<c00aa9e0>] call_timer_fn+0x7c/0x180
[ 132.216055] [<c00aac54>] run_timer_softirq+0x170/0x2b4
[ 132.221626] [<c00440c8>] __do_softirq+0x138/0x340
[ 132.226755] [<c00445f0>] irq_exit+0xbc/0x130
[ 132.231417] [<c009a618>] __handle_domain_irq+0x6c/0xe0
[ 132.237004] [<c00094ac>] omap_intc_handle_irq+0xa8/0xb8
[ 132.242673] [<c06c2824>] __irq_svc+0x44/0x5c
[ 132.247340] [<c06bffa8>] __mutex_unlock_slowpath+0x10c/0x1a4
[ 132.253462] [<c06bffa8>] __mutex_unlock_slowpath+0x10c/0x1a4
[ 132.259586] [<c01556a8>] unlock_rename+0x18/0x40
[ 132.264630] [<c015c128>] SyS_renameat2+0x258/0x4d0
[ 132.269844] [<c015c3e4>] SyS_rename+0x28/0x30
[ 132.274601] [<c000f5e0>] ret_fast_syscall+0x0/0x54
[ 132.279821] irq event stamp: 76337
[ 132.283380] hardirqs last enabled at (76337): [<c000f60c>] ret_fast_syscall+0x2c/0x54
[ 132.291686] hardirqs last disabled at (76336): [<c000f5ec>] ret_fast_syscall+0xc/0x54
[ 132.299896] softirqs last enabled at (75714): [<c004422c>] __do_softirq+0x29c/0x340
[ 132.308017] softirqs last disabled at (75709): [<c00445f0>] irq_exit+0xbc/0x130
[ 132.315683]
[ 132.315683] other info that might help us debug this:
[ 132.322515] Possible unsafe locking scenario:
[ 132.322515]
[ 132.328712] CPU0
[ 132.331274] ----
[ 132.333833] lock(module_lock);
[ 132.337228] <Interrupt>
[ 132.339970] lock(module_lock);
[ 132.343547]
[ 132.343547] *** DEADLOCK ***
[ 132.343547]
[ 132.349752] 1 lock held by sh/1254:
[ 132.353401] #0: (sb_writers#9){.+.+.+}, at: [<c014cff0>] vfs_write+0x13c/0x164
[ 132.361210]
[ 132.361210] stack backtrace:
[ 132.365788] CPU: 0 PID: 1254 Comm: sh Tainted: G W 4.1.0-268283-gca74796 #9
[ 132.374257] Hardware name: Generic AM33XX (Flattened Device Tree)
[ 132.380663] [<c00168c4>] (unwind_backtrace) from [<c00133c0>] (show_stack+0x10/0x14)
[ 132.388777] [<c00133c0>] (show_stack) from [<c06ba0b8>] (dump_stack+0x84/0x9c)
[ 132.396363] [<c06ba0b8>] (dump_stack) from [<c008beb0>] (print_usage_bug+0x1d8/0x2cc)
[ 132.404572] [<c008beb0>] (print_usage_bug) from [<c008c180>] (mark_lock+0x1dc/0x6c4)
[ 132.412690] [<c008c180>] (mark_lock) from [<c008d48c>] (__lock_acquire+0x860/0x2048)
[ 132.420809] [<c008d48c>] (__lock_acquire) from [<c008f4fc>] (lock_acquire+0xa8/0x124)
[ 132.429016] [<c008f4fc>] (lock_acquire) from [<c06c1d30>] (_raw_spin_lock+0x30/0x40)
[ 132.437147] [<c06c1d30>] (_raw_spin_lock) from [<bf07e6e4>] (get_table+0x14/0x5c [6lowpan])
[ 132.445922] [<bf07e6e4>] (get_table [6lowpan]) from [<bf07ebc0>] (lowpan_context_dbgfs_write+0x128/0x4ec [6lowpan])
[ 132.456860] [<bf07ebc0>] (lowpan_context_dbgfs_write [6lowpan]) from [<c014c6a8>] (__vfs_write+0x20/0xd8)
[ 132.466884] [<c014c6a8>] (__vfs_write) from [<c014cf44>] (vfs_write+0x90/0x164)
[ 132.474540] [<c014cf44>] (vfs_write) from [<c014d76c>] (SyS_write+0x44/0x9c)
[ 132.481931] [<c014d76c>] (SyS_write) from [<c000f5e0>] (ret_fast_syscall+0x0/0x54)
You should see the same by enable "CONFIG_PROVE_LOCKING". I think it's
because "spin_lock(&module_lock);" inside of "get_table" function. This
is called by lowpan_xmit which has a softirq context (I think the
experts says here bh (?bottom half?) are disabled). Anyway, you need to
call spin_lock_bh/spin_unlock_bh.
Linux device drivers says something similar:
"Finally, spin_lock_bh disables software interrupts before taking the
lock, but leaves hardware interrupts enabled." Without bh software
interrupts are still enabled.
> Signed-off-by: Lukasz Duda <lukasz.duda@xxxxxxxxxxxxx>
> Signed-off-by: Glenn Ruben Bakke <glenn.ruben.bakke@xxxxxxxxxxxxx>
> ---
> include/net/6lowpan.h | 35 ++++
> net/6lowpan/Makefile | 2 +-
> net/6lowpan/context.c | 551 ++++++++++++++++++++++++++++++++++++++++++++++++++
> net/6lowpan/context.h | 7 +
> 4 files changed, 594 insertions(+), 1 deletion(-)
> create mode 100644 net/6lowpan/context.c
> create mode 100644 net/6lowpan/context.h
>
> diff --git a/include/net/6lowpan.h b/include/net/6lowpan.h
> index 37ddbdf..ee3a455 100644
> --- a/include/net/6lowpan.h
> +++ b/include/net/6lowpan.h
> @@ -199,6 +199,27 @@
>
> extern struct dentry *lowpan_debugfs;
>
> +struct lowpan_context_table {
> + struct list_head list;
> +
> + /* Context entries */
> + struct net_device *netdev;
> + struct list_head context_entries;
> + atomic_t context_count;
> +};
> +
> +struct lowpan_context_entry {
> + struct list_head list;
> + struct rcu_head rcu;
> + struct lowpan_context_table *ctx_table;
> +
> + /* Context parameters */
> + u8 cid;
> + struct in6_addr prefix;
> + unsigned int prefix_len;
> + bool compression_flag;
> +};
> +
Is a list really necessary here? I assume that a context-id (one byte
long) with a maximum value of 255. And then it's splitted into sci and
dci, so we have a maximum of 16 and you already introduced nicely an
LOWPAN_CONTEXT_TABLE_SIZE for that.
Can't we simple to some array to have a fast lookup for lowpan_context_table[cid]
and if it's not null then we have an entry for that?
To lookup the CID by an ipv6 address, then we need to iterate the array
and using ipv6_prefix_equal.
> #ifdef DEBUG
> /* print data in line */
> static inline void raw_dump_inline(const char *caller, char *msg,
> @@ -337,6 +358,9 @@ lowpan_uncompress_size(const struct sk_buff *skb, u16 *dgram_offset)
> if (!(iphc0 & 0x03))
> ret++;
>
> + if (iphc1 & LOWPAN_IPHC_CID)
> + ret++;
> +
> ret += lowpan_addr_mode_size((iphc1 & LOWPAN_IPHC_SAM) >>
> LOWPAN_IPHC_SAM_BIT);
>
> @@ -374,6 +398,17 @@ lowpan_uncompress_size(const struct sk_buff *skb, u16 *dgram_offset)
> return skb->len + uncomp_header - ret;
> }
>
> +int lowpan_context_table_alloc(struct net_device *netdev);
> +int lowpan_context_table_free(struct net_device *netdev);
> +int lowpan_context_free_all(void);
> +int lowpan_context_add(struct net_device *netdev,
> + struct lowpan_context_entry *entry);
> +int lowpan_context_remove(struct lowpan_context_entry *entry);
> +struct lowpan_context_entry *
> +lowpan_context_decompress(struct net_device *netdev, u8 cid);
> +struct lowpan_context_entry *
> +lowpan_context_compress(struct net_device *netdev, struct in6_addr *addr);
> +
> int
> lowpan_header_decompress(struct sk_buff *skb, struct net_device *dev,
> const u8 *saddr, const u8 saddr_type,
> diff --git a/net/6lowpan/Makefile b/net/6lowpan/Makefile
> index eb8baa7..bda5be0 100644
> --- a/net/6lowpan/Makefile
> +++ b/net/6lowpan/Makefile
> @@ -1,6 +1,6 @@
> obj-$(CONFIG_6LOWPAN) += 6lowpan.o
>
> -6lowpan-y := iphc.o nhc.o
> +6lowpan-y := iphc.o nhc.o context.o
>
> #rfc6282 nhcs
> obj-$(CONFIG_6LOWPAN_NHC_DEST) += nhc_dest.o
> diff --git a/net/6lowpan/context.c b/net/6lowpan/context.c
> new file mode 100644
> index 0000000..00cd5af
> --- /dev/null
> +++ b/net/6lowpan/context.c
> @@ -0,0 +1,551 @@
> +/*
> + * Copyright (c) 2015 Nordic Semiconductor. All Rights Reserved.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 and
> + * only 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.
> + */
> +
> +#include <linux/if_arp.h>
> +#include <linux/netdevice.h>
> +#include <linux/module.h>
> +#include <linux/debugfs.h>
> +#include <linux/inet.h>
> +#include <linux/atomic.h>
> +
> +#include <net/ipv6.h>
> +#include <net/addrconf.h>
> +#include <net/6lowpan.h>
> +
> +#define LOWPAN_DBG(fmt, ...) pr_debug(fmt "\n", ##__VA_ARGS__)
> +
> +#define LOWPAN_CONTEXT_TABLE_SIZE 16
> +#define LOWPAN_CONTEXT_COMMAND_ADD "add"
> +#define LOWPAN_CONTEXT_COMMAND_REMOVE "remove"
> +
> +#define CHECK_CID_RANGE(cid) ((cid) > 0 && (cid) < LOWPAN_CONTEXT_TABLE_SIZE)
> +#define CHECK_PREFIX_RANGE(len) ((len) > 0 && (len) <= 128)
> +
> +static struct dentry *lowpan_context_debugfs;
> +
> +static LIST_HEAD(context_tables);
> +static DEFINE_SPINLOCK(module_lock);
> +
> +static inline void entry_update(struct lowpan_context_entry *entry,
please add lowpan prefix here to this function.
> + u8 cid,
> + struct in6_addr prefix,
> + unsigned int prefix_len,
> + bool compression_flag)
> +{
> + /* Fill context entry. */
> + entry->cid = cid;
> + entry->compression_flag = compression_flag;
> + entry->prefix = prefix;
> + entry->prefix_len = prefix_len;
> +}
> +
> +static inline void entry_free(struct lowpan_context_entry *entry)
lowpan prefix.
> +{
> + /* Increase number of available contexts. */
> + atomic_dec(&entry->ctx_table->context_count);
> +
> + list_del_rcu(&entry->list);
> + kfree_rcu(entry, rcu);
> +}
> +
> +static int entry_add(struct lowpan_context_table *ctx_table,
lowpan prefix.
> + u8 cid,
> + struct in6_addr prefix,
> + unsigned int prefix_len,
> + bool compression_flag)
> +{
> + struct lowpan_context_entry *new_entry = NULL;
> +
> + new_entry = kzalloc(sizeof(*new_entry), GFP_ATOMIC);
> + if (!new_entry)
> + return -ENOMEM;
> +
> + /* Fill context entry. */
> + new_entry->ctx_table = ctx_table;
> + entry_update(new_entry, cid, prefix, prefix_len, compression_flag);
> +
> + INIT_LIST_HEAD(&new_entry->list);
> + list_add_rcu(&new_entry->list, &ctx_table->context_entries);
> +
> + /* Increase number of available contexts. */
> + atomic_inc(&ctx_table->context_count);
> +
> + return 0;
> +}
> +
> +static void table_free(struct lowpan_context_table *ctx_table)
lowpan prefix.
> +{
> + struct lowpan_context_entry *entry = NULL;
> +
> + rcu_read_lock();
> +
> + /* Clear context table. */
> + if (atomic_read(&ctx_table->context_count)) {
> + list_for_each_entry_rcu(entry,
> + &ctx_table->context_entries,
> + list)
> + entry_free(entry);
> + }
> +
> + rcu_read_unlock();
> +
> + /* Remove context table. */
> + list_del(&ctx_table->list);
> + kfree(ctx_table);
> +}
> +
> +static inline struct net_device *find_netdev(const char *name)
lowpan prefix.
> +{
> + struct net_device *netdev;
> +
> + rcu_read_lock();
> + netdev = dev_get_by_name_rcu(&init_net, name);
> + rcu_read_unlock();
> +
> + return netdev;
> +}
> +
> +static struct lowpan_context_table *get_table(struct net_device *netdev)
> +{
> + struct lowpan_context_table *entry;
> + struct lowpan_context_table *net_table = NULL;
> +
> + spin_lock(&module_lock);
> +
> + list_for_each_entry(entry, &context_tables, list) {
> + if (entry->netdev == netdev) {
> + /* Table has been found. */
> + net_table = entry;
> + break;
> + }
> + }
> +
> + spin_unlock(&module_lock);
> +
I know why you need such functionality. This is okay for now. But I
already thought about a nicer handling for that (which is also useful
for other mechanism). The idea is:
The netdev structure has some private pointer "netdev->priv". Currently
bluetooth 6lowpan/802.15.4 6lowpan do their own stuff inside this struct
which is okay. But we should provide some "upper class" struct for all
ARPHRD_6LOWPAN, which looks like:
-----------------------------
| 6LOWPAN_ARPHRD_STRUCT | <-- All ARPHRD_6LOWPAN have this struct as first
-----------------------------
| PRIVATE_DATA | <-- 802.15.4/btle own stuff (private struct of subsystem) simple a
| | "u8 priv __aligned(sizeof(void *));" inside ARPHRD_6LOWPAN which need to be at last
-----------------------------
Then you can put the net_table into the "6LOWPAN_ARPHRD_STRUCT" and cast
the "netdev->priv" pointer to "6LOWPAN_ARPHRD_STRUCT".
We really need such thing to avoid the above search&found functionality.
We should introduce such behaviour at first, then you can rebase your
stuff on it.
Also we need some functionality lowpan_alloc_netdev which ensure the
priv size is "sizeof(6LOWPAN_ARPHRD_STRUCT) + sizeof(PRIVATE_DATA)".
In upper layers like IPv6 you can do the following then:
if (dev->type == ARPHRD_6LOWPAN) {
6LOWPAN_ARPHRD_STRUCT foobar = (struct 6LOWPAN_ARPHRD_STRUCT *)dev->priv;
...do great cid handling here...
}
I hope this will also help you by implementing 6CO.
btw: (struct 6LOWPAN_ARPHRD_STRUCT *) should be implemented by a macro.
So please begin at first to add such functionality, please. Is that okay
for you?
> + return net_table;
> +}
> +
> +static struct lowpan_context_entry *
> +get_ctx_by_cid(struct lowpan_context_table *table, u8 cid)
> +{
> + struct lowpan_context_entry *entry;
> + struct lowpan_context_entry *context = NULL;
> +
> + rcu_read_lock();
> +
> + list_for_each_entry_rcu(entry, &table->context_entries, list) {
> + if (entry->cid == cid) {
> + /* Context entry has been found. */
> + context = entry;
> + break;
> + }
> + }
> +
> + rcu_read_unlock();
> +
> + return context;
> +}
> +
> +static struct lowpan_context_entry *
> +get_ctx_by_addr(struct lowpan_context_table *table, struct in6_addr *addr)
> +{
> + struct lowpan_context_entry *entry;
> + struct lowpan_context_entry *best_match = NULL;
> + unsigned int compare_len;
> +
> + rcu_read_lock();
> +
> + list_for_each_entry_rcu(entry, &table->context_entries, list) {
> + if (!entry->compression_flag)
> + continue;
> +
> + compare_len = entry->prefix_len >= 64 ? entry->prefix_len : 64;
> + if (ipv6_prefix_equal(addr, &entry->prefix, compare_len)) {
> + /* Valid context entry has been found. Check if prefix
> + * can cover more bytes than previous one.
> + */
> + if (!best_match ||
> + (best_match->prefix_len < entry->prefix_len))
> + best_match = entry;
> + }
> + }
> +
> + rcu_read_unlock();
> +
> + return best_match;
> +}
> +
> +ssize_t lowpan_context_dbgfs_write(struct file *fp,
> + const char __user *user_buffer,
> + size_t count,
> + loff_t *position)
> +{
> + char buf[128];
> + char str_operation[16];
> + char str_interface[16];
> + char str_ipv6addr[40];
> + size_t buf_size = min(count, sizeof(buf) - 1);
> + int n;
> + int ret;
> + u8 cid;
> + unsigned int prefix_length;
> + unsigned int c_flag;
> + struct in6_addr ctx_prefix;
> + struct net_device *netdev;
> + struct lowpan_context_table *ctx_table;
> + struct lowpan_context_entry *entry;
> +
> + memset(&ctx_prefix, 0, sizeof(ctx_prefix));
> +
> + if (copy_from_user(buf, user_buffer, buf_size))
> + return -EFAULT;
> +
> + buf[buf_size] = '\0';
> +
> + /* Parse input parameters. */
> + n = sscanf(buf, "%s %s %hhd %s %d %d",
> + str_operation, str_interface, &cid, str_ipv6addr,
> + &prefix_length, &c_flag);
> +
> + netdev = find_netdev(str_interface);
> + /* Look up for net device. */
> + if (!netdev) {
> + LOWPAN_DBG("Cannot find given interface");
> + return -EINVAL;
> + }
> +
> + if (!CHECK_CID_RANGE(cid)) {
> + LOWPAN_DBG("CID value is out of range");
> + return -EINVAL;
> + }
> +
> + /* Get context table. */
> + ctx_table = get_table(netdev);
> +
> + if (!ctx_table) {
> + LOWPAN_DBG("Cannot find context table for %s interface",
> + str_interface);
> + return -EINVAL;
> + }
> +
> + entry = get_ctx_by_cid(ctx_table, cid);
> +
> + /* Execute command. */
> + if (!memcmp(str_operation, LOWPAN_CONTEXT_COMMAND_ADD,
> + sizeof(LOWPAN_CONTEXT_COMMAND_ADD))) {
> + /* Parse IPv6 address. */
> + in6_pton(str_ipv6addr,
> + sizeof(str_ipv6addr),
> + ctx_prefix.s6_addr,
> + '\0',
> + NULL);
> +
> + /* Check parameters. */
> + if (ipv6_addr_any(&ctx_prefix) ||
> + !CHECK_PREFIX_RANGE(prefix_length)) {
> + LOWPAN_DBG("Given parameters are not valid");
> + return -EINVAL;
> + }
> +
> + LOWPAN_DBG("Got request: I:%s CID:%d Prefix:%pI6c/%d C:%d",
> + str_interface, cid, &ctx_prefix, prefix_length,
> + !!c_flag);
> +
> + /* Check if entry for given CID already exists. */
> + if (entry) {
> + /* Just update parameters. */
> + rcu_read_lock();
> + entry_update(entry, cid, ctx_prefix, prefix_length,
> + !!c_flag);
> + rcu_read_unlock();
> + } else {
> + /* Create a new entry. */
> + ret = entry_add(ctx_table, cid, ctx_prefix,
> + prefix_length, !!c_flag);
> + if (ret < 0) {
> + LOWPAN_DBG("Cannot add context entry");
> + return ret;
> + }
> + }
> + } else if (memcmp(str_operation, LOWPAN_CONTEXT_COMMAND_REMOVE,
> + sizeof(LOWPAN_CONTEXT_COMMAND_REMOVE)) == 0) {
> + LOWPAN_DBG("Got new remove request: I:%s CID:%d",
> + str_interface, cid);
> +
> + if (!entry) {
> + LOWPAN_DBG("Cannot find context entry");
> + return -EINVAL;
> + }
> +
> + rcu_read_lock();
> + entry_free(entry);
> + rcu_read_unlock();
> + } else {
> + LOWPAN_DBG("Invalid command - Cannot process the request");
> + return -EINVAL;
> + }
> +
> + return count;
> +}
> +
> +static int lowpan_context_show(struct seq_file *f, void *ptr)
> +{
> + struct lowpan_context_table *table;
> + struct lowpan_context_entry *entry;
> +
> + list_for_each_entry(table, &context_tables, list) {
> + if (!atomic_read(&table->context_count))
> + break;
> +
> + seq_printf(f, "Context table of interface %s\r\n\r\n",
> + table->netdev->name);
> + seq_printf(f, "%-3s %-39s %-3s %-3s \r\n",
> + "CID", "Prefix", "Len", "CF");
> +
> + list_for_each_entry_rcu(entry, &table->context_entries, list)
> + seq_printf(f, "%-3d %-39pI6c %-3d %-3s \r\n",
> + entry->cid,
> + &entry->prefix,
> + entry->prefix_len,
> + entry->compression_flag ? "1" : "0");
> + seq_puts(f, "\r\n\r\n");
> + }
> +
> + return 0;
> +}
> +
> +int lowpan_context_dbgfs_open(struct inode *inode, struct file *file)
> +{
> + return single_open(file, lowpan_context_show, inode->i_private);
> +}
> +
> +int lowpan_context_table_alloc(struct net_device *netdev)
> +{
> + struct lowpan_context_table *ctx_table = NULL;
> +
> + if (!netdev) {
> + LOWPAN_DBG("Network device has to be specified");
> + return -EPERM;
> + }
> +
> + /* Look for context table. */
> + ctx_table = get_table(netdev);
> +
> + if (ctx_table) {
> + LOWPAN_DBG("Context table already exists for interface %s %p",
> + netdev->name, ctx_table);
> + return -EEXIST;
> + }
> +
> + ctx_table = kzalloc(sizeof(*ctx_table), GFP_ATOMIC);
> + if (!ctx_table)
> + return -ENOMEM;
> +
> + /* Assign network device to context table. */
> + ctx_table->netdev = netdev;
> +
> + /* Initialize contexts list. */
> + INIT_LIST_HEAD(&ctx_table->context_entries);
> +
> + spin_lock(&module_lock);
> + INIT_LIST_HEAD(&ctx_table->list);
> + list_add_rcu(&ctx_table->list, &context_tables);
> + spin_unlock(&module_lock);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(lowpan_context_table_alloc);
> +
> +int lowpan_context_table_free(struct net_device *netdev)
> +{
> + struct lowpan_context_table *ctx_table = NULL;
> +
> + if (!netdev) {
> + LOWPAN_DBG("Network device has to be specified");
> + return -EPERM;
> + }
> +
> + /* Look for context table. */
> + ctx_table = get_table(netdev);
> + if (!ctx_table) {
> + LOWPAN_DBG("Cannot find context table for interface %s",
> + netdev->name);
> + return -ENOENT;
> + }
> +
> + spin_lock(&module_lock);
> + table_free(ctx_table);
> + spin_unlock(&module_lock);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(lowpan_context_table_free);
> +
> +int lowpan_context_add(struct net_device *netdev,
> + struct lowpan_context_entry *entry)
> +{
> + int ret;
> + struct lowpan_context_table *ctx_table = NULL;
> + struct lowpan_context_entry *stored_entry = NULL;
> +
> + if (!entry || !netdev) {
> + LOWPAN_DBG("Parameters are incorrect");
> + return -EPERM;
> + }
> +
> + /* Get context table. */
> + ctx_table = get_table(netdev);
> + if (!ctx_table) {
> + LOWPAN_DBG("Cannot find context table for %s interface",
> + netdev->name);
> + return -EINVAL;
> + }
> +
> + stored_entry = get_ctx_by_cid(ctx_table, entry->cid);
> +
> + /* Check if entry for given CID already exists. */
> + if (entry) {
> + /* Just update parameters. */
> + rcu_read_lock();
> + entry_update(stored_entry, entry->cid, entry->prefix,
> + entry->prefix_len, entry->compression_flag);
> + rcu_read_unlock();
> + } else {
> + /* Create a new entry. */
> + ret = entry_add(ctx_table, entry->cid, entry->prefix,
> + entry->prefix_len, entry->compression_flag);
> +
> + if (ret < 0) {
> + LOWPAN_DBG("Cannot add context entry");
> + return ret;
> + }
> + }
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(lowpan_context_add);
> +
Don't export function which isn't used by other modules. Maybe you
prepared for using this function for the 6CO field in ipv6. If yes, we
can do that later.
> +int lowpan_context_remove(struct lowpan_context_entry *entry)
> +{
> + if (!entry) {
> + LOWPAN_DBG("Given entry is NULL");
> + return -EPERM;
> + }
> +
> + /* Free given entry. */
> + rcu_read_lock();
> + entry_free(entry);
> + rcu_read_unlock();
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(lowpan_context_remove);
> +
same here.
> +struct lowpan_context_entry *
> +lowpan_context_decompress(struct net_device *netdev, u8 cid)
> +{
> + struct lowpan_context_table *ctx_table = NULL;
> + struct lowpan_context_entry *entry = NULL;
> +
> + if (!netdev) {
> + LOWPAN_DBG("Network device has to be specified");
> + return NULL;
> + }
> +
> + /* Get proper interface table. */
> + ctx_table = get_table(netdev);
> + if (!ctx_table) {
> + LOWPAN_DBG("Cannot find context table for interface %s",
> + netdev->name);
> + return NULL;
> + }
> +
> + /* Search for given CID. */
> + entry = get_ctx_by_cid(ctx_table, cid);
> + if (!entry) {
> + LOWPAN_DBG("There is no context of id:%d for interface %s",
> + cid, netdev->name);
> + return NULL;
> + }
> +
> + LOWPAN_DBG("Found context prefix for context of id:%d - %pI6c",
> + entry->cid, &entry->prefix);
> +
> + return entry;
> +}
> +EXPORT_SYMBOL_GPL(lowpan_context_decompress);
> +
same here.
> +struct lowpan_context_entry *lowpan_context_compress(struct net_device *netdev,
> + struct in6_addr *addr)
> +{
> + struct lowpan_context_table *ctx_table = NULL;
> + struct lowpan_context_entry *entry = NULL;
> +
> + if (!netdev || !addr) {
> + LOWPAN_DBG("Network device and address has to be specified");
> + return NULL;
> + }
> +
> + /* Get proper interface table. */
> + ctx_table = get_table(netdev);
> + if (!ctx_table) {
> + LOWPAN_DBG("Cannot find context table for interface %s",
> + netdev->name);
> + return NULL;
> + }
> +
> + /* Search for given address. */
> + entry = get_ctx_by_addr(ctx_table, addr);
> + if (!entry) {
> + LOWPAN_DBG("No context for address %pI6c for interface %s",
> + addr, netdev->name);
> + return NULL;
> + }
> +
> + LOWPAN_DBG("Found context of id:%d", entry->cid);
> +
> + /* Return null in case no compression capability in found context */
> + return entry;
> +}
> +EXPORT_SYMBOL_GPL(lowpan_context_compress);
> +
same here.
> +const struct file_operations lowpan_context_fops = {
> + .open = lowpan_context_dbgfs_open,
> + .read = seq_read,
> + .write = lowpan_context_dbgfs_write,
> + .llseek = seq_lseek,
> + .release = single_release
> +};
> +
> +void lowpan_context_init(void)
> +{
> + lowpan_context_debugfs = debugfs_create_file("context", 0664,
> + lowpan_debugfs, NULL,
> + &lowpan_context_fops);
> +}
> +EXPORT_SYMBOL_GPL(lowpan_context_init);
> +
same here.
> +void lowpan_context_uninit(void)
> +{
> + struct lowpan_context_table *entry = NULL;
> +
> + spin_lock(&module_lock);
> +
> + list_for_each_entry(entry, &context_tables, list)
> + table_free(entry);
> +
> + spin_unlock(&module_lock);
> +
> + debugfs_remove(lowpan_context_debugfs);
> +}
> +EXPORT_SYMBOL_GPL(lowpan_context_uninit);
same here.
> diff --git a/net/6lowpan/context.h b/net/6lowpan/context.h
> new file mode 100644
> index 0000000..88303b5
> --- /dev/null
> +++ b/net/6lowpan/context.h
> @@ -0,0 +1,7 @@
> +#ifndef __6LOWPAN_CONTEXT_H
> +#define __6LOWPAN_CONTEXT_H
> +
> +void lowpan_context_init(void);
> +void lowpan_context_uninit(void);
> +
> +#endif /* __6LOWPAN_CONTEXT_H */
> --
> 2.1.4
>
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