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Date: Wed, 25 Nov 2015 18:12:25 +0100
From: Stefan Schmidt <stefan@....samsung.com>
To: Alexander Aring <alex.aring@...il.com>, linux-wpan@...r.kernel.org
Cc: linux-bluetooth@...r.kernel.org, netdev@...r.kernel.org,
kernel@...gutronix.de, mcr@...delman.ca, lukasz.duda@...dicsemi.no,
martin.gergeleit@...rm.de
Subject: Re: [RFCv2 bluetooth-next 3/3] 6lowpan: iphc: add support for
stateful compression
Helllo.
On 17/11/15 23:33, Alexander Aring wrote:
> This patch introduce support for IPHC stateful address compression. It
> will offer three debugfs per interface entries, which are:
>
> - dci_table: destination context indentifier table
> - sci_table: source context indentifier table
> - mcast_sci_table: multicast context identifier table
>
> Example to setup a context id:
>
> A "cat /sys/kernel/debug/6lowpan/lowpan0/dci_table" will display all
> contexts which are available. Example:
>
> ID ipv6-address/prefix-length state
> 0 0000:0000:0000:0000:0000:0000:0000:0000/000 0
> 1 0000:0000:0000:0000:0000:0000:0000:0000/000 0
> 2 0000:0000:0000:0000:0000:0000:0000:0000/000 0
> 3 0000:0000:0000:0000:0000:0000:0000:0000/000 0
> 4 0000:0000:0000:0000:0000:0000:0000:0000/000 0
> 5 0000:0000:0000:0000:0000:0000:0000:0000/000 0
> 6 0000:0000:0000:0000:0000:0000:0000:0000/000 0
> 7 0000:0000:0000:0000:0000:0000:0000:0000/000 0
> 8 0000:0000:0000:0000:0000:0000:0000:0000/000 0
> 9 0000:0000:0000:0000:0000:0000:0000:0000/000 0
> 10 0000:0000:0000:0000:0000:0000:0000:0000/000 0
> 11 0000:0000:0000:0000:0000:0000:0000:0000/000 0
> 12 0000:0000:0000:0000:0000:0000:0000:0000/000 0
> 13 0000:0000:0000:0000:0000:0000:0000:0000/000 0
> 14 0000:0000:0000:0000:0000:0000:0000:0000/000 0
> 15 0000:0000:0000:0000:0000:0000:0000:0000/000 0
>
> For setting a context e.g. context id 0, context 2001::, prefix-length
> 64.
>
> Hint: Simple copy one line and then maniuplate it.
>
> echo "0 2001:0000:0000:0000:0000:0000:0000:0000/64 1" >
> /sys/kernel/debug/6lowpan/lowpan0/dci_table
>
> The state will display currently if the context is disabled(0) or
> enabled(1).
>
> On transmit side:
>
> The IPHC code will automatically search for a context which would be
> match for the address. Then it will be use the context which the
> best compression, means the longest prefix which match will be used.
>
> Example:
>
> 2001::/126 vs 2001::/127 - the 2001::/127 can be full compressed if the
> last bit of the address which has the prefix 2001::/127 is the same like
> the IID from the Encapsulating Header. A context ID can also be a
> 2001::1/128, which is then a full ipv6 address.
>
> On Receive side:
>
> If there is a context defined (when CID not available then it's the
> default context 0) then it will be used, if the header doesn't set
> SAC or DAC bit thens, it will be dropped.
>
> Signed-off-by: Alexander Aring <alex.aring@...il.com>
> ---
> include/net/6lowpan.h | 62 ++++++
> net/6lowpan/6lowpan_i.h | 3 +
> net/6lowpan/Kconfig | 1 +
> net/6lowpan/core.c | 17 ++
> net/6lowpan/debugfs.c | 109 +++++++++++
> net/6lowpan/iphc.c | 500 ++++++++++++++++++++++++++++++++++++++++++------
> 6 files changed, 635 insertions(+), 57 deletions(-)
>
> diff --git a/include/net/6lowpan.h b/include/net/6lowpan.h
> index e484898..6e8d30e 100644
> --- a/include/net/6lowpan.h
> +++ b/include/net/6lowpan.h
> @@ -75,6 +75,8 @@
> #define LOWPAN_IPHC_MAX_HC_BUF_LEN (sizeof(struct ipv6hdr) + \
> LOWPAN_IPHC_MAX_HEADER_LEN + \
> LOWPAN_NHC_MAX_HDR_LEN)
> +/* SCI/DCI is 4 bit width, so we have maximum 16 entries */
> +#define LOWPAN_IPHC_CI_TABLE_SIZE (1 << 4)
>
> #define LOWPAN_DISPATCH_IPV6 0x41 /* 01000001 = 65 */
> #define LOWPAN_DISPATCH_IPHC 0x60 /* 011xxxxx = ... */
> @@ -98,9 +100,45 @@ enum lowpan_lltypes {
> LOWPAN_LLTYPE_IEEE802154,
> };
>
> +enum lowpan_iphc_ctx_states {
> + LOWPAN_IPHC_CTX_STATE_DISABLED,
> + LOWPAN_IPHC_CTX_STATE_ENABLED,
> +
> + __LOWPAN_IPHC_CTX_STATE_INVALID,
> + LOWPAN_IPHC_CTX_STATE_MAX = __LOWPAN_IPHC_CTX_STATE_INVALID - 1,
> +};
> +
You are expecting more states here besides enabled and disabled? Because
normally a bool would be fine here and an enum overkill. If you have
more states pending it makes sense to have the enum though.
> +struct lowpan_iphc_ctx {
> + enum lowpan_iphc_ctx_states state;
> + u8 id;
> + struct in6_addr addr;
> + u8 prefix_len;
> +};
> +
> +struct lowpan_iphc_ctx_ops {
> + bool (*valid_prefix)(const struct lowpan_iphc_ctx *ctx);
> + int (*update)(struct lowpan_iphc_ctx *table,
> + const struct lowpan_iphc_ctx *ctx);
> + struct lowpan_iphc_ctx *(*get_by_id)(const struct net_device *dev,
> + struct lowpan_iphc_ctx *table,
> + u8 id);
> + struct lowpan_iphc_ctx *(*get_by_addr)(const struct net_device *dev,
> + struct lowpan_iphc_ctx *table,
> + const struct in6_addr *addr);
> +};
> +
> +struct lowpan_iphc_ctx_table {
> + spinlock_t lock;
> + const struct lowpan_iphc_ctx_ops *ops;
> + struct lowpan_iphc_ctx table[LOWPAN_IPHC_CI_TABLE_SIZE];
> +};
> +
> struct lowpan_priv {
> enum lowpan_lltypes lltype;
> struct dentry *iface_debugfs;
> + struct lowpan_iphc_ctx_table iphc_dci;
> + struct lowpan_iphc_ctx_table iphc_sci;
> + struct lowpan_iphc_ctx_table iphc_mcast_dci;
>
> /* must be last */
> u8 priv[0] __aligned(sizeof(void *));
> @@ -125,6 +163,30 @@ struct lowpan_802154_cb *lowpan_802154_cb(const struct sk_buff *skb)
> return (struct lowpan_802154_cb *)skb->cb;
> }
>
> +static inline int lowpan_ctx_update(struct lowpan_iphc_ctx_table *t,
> + const struct lowpan_iphc_ctx *ctx)
> +{
> + if (!t->ops->valid_prefix(ctx))
> + return -EINVAL;
> +
> + return t->ops->update(t->table, ctx);
> +}
> +
> +static inline struct lowpan_iphc_ctx *
> +lowpan_ctx_by_id(const struct net_device *dev, struct lowpan_iphc_ctx_table *t,
> + u8 id)
> +{
> + return t->ops->get_by_id(dev, t->table, id);
> +}
> +
> +static inline struct lowpan_iphc_ctx *
> +lowpan_ctx_by_addr(const struct net_device *dev,
> + struct lowpan_iphc_ctx_table *t,
> + const struct in6_addr *addr)
> +{
> + return t->ops->get_by_addr(dev, t->table, addr);
> +}
> +
> #ifdef DEBUG
> /* print data in line */
> static inline void raw_dump_inline(const char *caller, char *msg,
> diff --git a/net/6lowpan/6lowpan_i.h b/net/6lowpan/6lowpan_i.h
> index 33b2605..1312340 100644
> --- a/net/6lowpan/6lowpan_i.h
> +++ b/net/6lowpan/6lowpan_i.h
> @@ -3,6 +3,9 @@
>
> #include <linux/netdevice.h>
>
> +extern const struct lowpan_iphc_ctx_ops iphc_ctx_unicast_ops;
> +extern const struct lowpan_iphc_ctx_ops iphc_ctx_mcast_ops;
> +
> #ifdef CONFIG_6LOWPAN_DEBUGFS
> int lowpan_dev_debugfs_init(struct net_device *dev);
> void lowpan_dev_debugfs_uninit(struct net_device *dev);
> diff --git a/net/6lowpan/Kconfig b/net/6lowpan/Kconfig
> index 01c901c..7ecedd7 100644
> --- a/net/6lowpan/Kconfig
> +++ b/net/6lowpan/Kconfig
> @@ -8,6 +8,7 @@ menuconfig 6LOWPAN
> config 6LOWPAN_DEBUGFS
> bool "6LoWPAN debugfs support"
> depends on 6LOWPAN
> + depends on DEBUG_FS
This looks like a fix that should be merged into the first patch, no?
> ---help---
> This enables 6LoWPAN debugfs support. For example to manipulate
> IPHC context information at runtime.
> diff --git a/net/6lowpan/core.c b/net/6lowpan/core.c
> index fe58509..d354c5b 100644
> --- a/net/6lowpan/core.c
> +++ b/net/6lowpan/core.c
> @@ -19,6 +19,8 @@
>
> int lowpan_netdev_setup(struct net_device *dev, enum lowpan_lltypes lltype)
> {
> + int i;
> +
> dev->addr_len = EUI64_ADDR_LEN;
> dev->type = ARPHRD_6LOWPAN;
> dev->mtu = IPV6_MIN_MTU;
> @@ -26,6 +28,21 @@ int lowpan_netdev_setup(struct net_device *dev, enum lowpan_lltypes lltype)
>
> lowpan_priv(dev)->lltype = lltype;
>
> + spin_lock_init(&lowpan_priv(dev)->iphc_dci.lock);
> + lowpan_priv(dev)->iphc_dci.ops = &iphc_ctx_unicast_ops;
> +
> + spin_lock_init(&lowpan_priv(dev)->iphc_sci.lock);
> + lowpan_priv(dev)->iphc_sci.ops = &iphc_ctx_unicast_ops;
> +
> + spin_lock_init(&lowpan_priv(dev)->iphc_mcast_dci.lock);
> + lowpan_priv(dev)->iphc_mcast_dci.ops = &iphc_ctx_mcast_ops;
> +
> + for (i = 0; i < LOWPAN_IPHC_CI_TABLE_SIZE; i++) {
> + lowpan_priv(dev)->iphc_dci.table[i].id = i;
> + lowpan_priv(dev)->iphc_sci.table[i].id = i;
> + lowpan_priv(dev)->iphc_mcast_dci.table[i].id = i;
> + }
> +
> return lowpan_dev_debugfs_init(dev);
> }
> EXPORT_SYMBOL(lowpan_netdev_setup);
> diff --git a/net/6lowpan/debugfs.c b/net/6lowpan/debugfs.c
> index b0a26fd..d6481eb 100644
> --- a/net/6lowpan/debugfs.c
> +++ b/net/6lowpan/debugfs.c
> @@ -18,15 +18,124 @@
>
> static struct dentry *lowpan_debugfs;
>
> +static int lowpan_context_show(struct seq_file *file, void *offset)
> +{
> + struct lowpan_iphc_ctx_table *t = file->private;
> + int i;
> +
> + seq_printf(file, "%-2s %-43s %s\n", "ID", "ipv6-address/prefix-length",
> + "state");
> +
> + spin_lock_bh(&t->lock);
> + for (i = 0; i < LOWPAN_IPHC_CI_TABLE_SIZE; i++) {
> + seq_printf(file,
> + "%-2d %04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x/%03d %d\n",
> + t->table[i].id,
> + be16_to_cpu(t->table[i].addr.s6_addr16[0]),
> + be16_to_cpu(t->table[i].addr.s6_addr16[1]),
> + be16_to_cpu(t->table[i].addr.s6_addr16[2]),
> + be16_to_cpu(t->table[i].addr.s6_addr16[3]),
> + be16_to_cpu(t->table[i].addr.s6_addr16[4]),
> + be16_to_cpu(t->table[i].addr.s6_addr16[5]),
> + be16_to_cpu(t->table[i].addr.s6_addr16[6]),
> + be16_to_cpu(t->table[i].addr.s6_addr16[7]),
> + t->table[i].prefix_len, t->table[i].state);
> + }
> + spin_unlock_bh(&t->lock);
> +
> + return 0;
> +}
> +
> +static int lowpan_context_dbgfs_open(struct inode *inode, struct file *file)
> +{
> + return single_open(file, lowpan_context_show, inode->i_private);
> +}
> +
> +static ssize_t lowpan_context_dbgfs_write(struct file *fp,
> + const char __user *user_buf,
> + size_t count, loff_t *ppos)
> +{
> + char buf[128] = { };
> + struct seq_file *file = fp->private_data;
> + struct lowpan_iphc_ctx_table *t = file->private;
> + struct lowpan_iphc_ctx ctx;
> + int status = count, n, id, state, i, prefix_len, ret;
> + unsigned int addr[8];
> +
> + if (copy_from_user(&buf, user_buf, min_t(size_t, sizeof(buf) - 1,
> + count))) {
> + status = -EFAULT;
> + goto out;
> + }
> +
> + n = sscanf(buf, "%d %04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x/%d %d",
> + &id, &addr[0], &addr[1], &addr[2], &addr[3], &addr[4],
> + &addr[5], &addr[6], &addr[7], &prefix_len, &state);
> + if (n != 11) {
11 more like a magic number here. Not to bad, but a define could be nice.
> + status = -EIO;
> + goto out;
> + }
> +
> + if (id > LOWPAN_IPHC_CI_TABLE_SIZE - 1 ||
> + state > LOWPAN_IPHC_CTX_STATE_MAX || prefix_len > 128) {
> + status = -EINVAL;
> + goto out;
> + }
> +
> + ctx.id = id;
> + ctx.state = state;
> + ctx.prefix_len = prefix_len;
> +
> + for (i = 0; i < 8; i++)
> + ctx.addr.s6_addr16[i] = cpu_to_be16(addr[i] & 0xffff);
> +
> + spin_lock_bh(&t->lock);
> + ret = lowpan_ctx_update(t, &ctx);
> + if (ret < 0)
> + status = ret;
> + spin_unlock_bh(&t->lock);
> +
> +out:
> + return status;
> +}
> +
> +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,
> +};
> +
> int lowpan_dev_debugfs_init(struct net_device *dev)
> {
> struct lowpan_priv *lpriv = lowpan_priv(dev);
> + static struct dentry *dentry;
>
> /* creating the root */
> lpriv->iface_debugfs = debugfs_create_dir(dev->name, lowpan_debugfs);
> if (!lpriv->iface_debugfs)
> goto fail;
>
> + dentry = debugfs_create_file("dci_table", 0664, lpriv->iface_debugfs,
> + &lowpan_priv(dev)->iphc_dci,
> + &lowpan_context_fops);
> + if (!dentry)
> + goto fail;
> +
> + dentry = debugfs_create_file("sci_table", 0664, lpriv->iface_debugfs,
> + &lowpan_priv(dev)->iphc_sci,
> + &lowpan_context_fops);
> + if (!dentry)
> + goto fail;
> +
> + dentry = debugfs_create_file("mcast_dci_table", 0664,
> + lpriv->iface_debugfs,
> + &lowpan_priv(dev)->iphc_mcast_dci,
> + &lowpan_context_fops);
> + if (!dentry)
> + goto fail;
> +
> return 0;
>
> fail:
> diff --git a/net/6lowpan/iphc.c b/net/6lowpan/iphc.c
> index 346b5c1..5974ea5 100644
> --- a/net/6lowpan/iphc.c
> +++ b/net/6lowpan/iphc.c
> @@ -56,6 +56,7 @@
> /* special link-layer handling */
> #include <net/mac802154.h>
>
> +#include "6lowpan_i.h"
> #include "nhc.h"
>
> /* Values of fields within the IPHC encoding first byte */
> @@ -147,6 +148,9 @@
> (((a)->s6_addr16[6]) == 0) && \
> (((a)->s6_addr[14]) == 0))
>
> +#define LOWPAN_IPHC_CID_DCI(cid) (cid & 0x0f)
> +#define LOWPAN_IPHC_CID_SCI(cid) ((cid & 0xf0) >> 4)
> +
> static inline void iphc_uncompress_eui64_lladdr(struct in6_addr *ipaddr,
> const void *lladdr)
> {
> @@ -259,30 +263,59 @@ static int uncompress_addr(struct sk_buff *skb, const struct net_device *dev,
> /* Uncompress address function for source context
> * based address(non-multicast).
> */
> -static int uncompress_context_based_src_addr(struct sk_buff *skb,
> - struct in6_addr *ipaddr,
> - u8 address_mode)
> +static int uncompress_ctx_addr(struct sk_buff *skb,
> + const struct net_device *dev,
> + const struct lowpan_iphc_ctx *ctx,
> + struct in6_addr *ipaddr, u8 address_mode,
> + const void *lladdr)
> {
> + bool fail;
> +
> switch (address_mode) {
> - case LOWPAN_IPHC_SAM_00:
> - /* unspec address ::
> + /* SAM and DAM are the same here */
> + case LOWPAN_IPHC_DAM_00:
> + fail = false;
> + /* SAM_00 -> unspec address ::
> * Do nothing, address is already ::
> + *
> + * DAM 00 -> reserved should never occur.
> */
> break;
> case LOWPAN_IPHC_SAM_01:
> - /* TODO */
> + case LOWPAN_IPHC_DAM_01:
> + fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[8], 8);
> + ipv6_addr_prefix_cpy(ipaddr, &ctx->addr, ctx->prefix_len);
> + break;
> case LOWPAN_IPHC_SAM_10:
> - /* TODO */
> + case LOWPAN_IPHC_DAM_10:
> + ipaddr->s6_addr[11] = 0xFF;
> + ipaddr->s6_addr[12] = 0xFE;
> + fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[14], 2);
> + ipv6_addr_prefix_cpy(ipaddr, &ctx->addr, ctx->prefix_len);
> + break;
> case LOWPAN_IPHC_SAM_11:
> - /* TODO */
> - netdev_warn(skb->dev, "SAM value 0x%x not supported\n",
> - address_mode);
> - return -EINVAL;
> + case LOWPAN_IPHC_DAM_11:
> + fail = false;
> + switch (lowpan_priv(dev)->lltype) {
> + case LOWPAN_LLTYPE_IEEE802154:
> + iphc_uncompress_802154_lladdr(ipaddr, lladdr);
> + break;
> + default:
> + iphc_uncompress_eui64_lladdr(ipaddr, lladdr);
> + break;
> + }
> + ipv6_addr_prefix_cpy(ipaddr, &ctx->addr, ctx->prefix_len);
> + break;
> default:
> pr_debug("Invalid sam value: 0x%x\n", address_mode);
> return -EINVAL;
> }
>
> + if (fail) {
> + pr_debug("Failed to fetch skb data\n");
> + return -EIO;
> + }
> +
> raw_dump_inline(NULL,
> "Reconstructed context based ipv6 src addr is",
> ipaddr->s6_addr, 16);
> @@ -346,6 +379,33 @@ static int lowpan_uncompress_multicast_daddr(struct sk_buff *skb,
> return 0;
> }
>
> +static int lowpan_uncompress_multicast_ctx_daddr(struct sk_buff *skb,
> + struct lowpan_iphc_ctx *ctx,
> + struct in6_addr *ipaddr,
> + u8 address_mode)
> +{
> + struct in6_addr network_pfx = {};
> + bool fail;
> +
> + if (address_mode != LOWPAN_IPHC_DAM_00)
> + return -EINVAL;
> +
> + ipaddr->s6_addr[0] = 0xFF;
> + fail = lowpan_fetch_skb(skb, &ipaddr->s6_addr[1], 2);
> + fail |= lowpan_fetch_skb(skb, &ipaddr->s6_addr[12], 4);
> + /* take prefix_len and network prefix from the context */
> + ipaddr->s6_addr[3] = ctx->prefix_len;
> + /* get network prefix to copy into multicast address */
> + ipv6_addr_prefix(&network_pfx, &ctx->addr, ctx->prefix_len);
> + /* setting network prefix */
> + memcpy(&ipaddr->s6_addr[4], &network_pfx, 8);
> +
> + if (fail < 0)
> + return -EIO;
> +
> + return 0;
> +}
> +
> /* get the ecn values from iphc tf format and set it to ipv6hdr */
> static inline void lowpan_iphc_tf_set_ecn(struct ipv6hdr *hdr, const u8 *tf)
> {
> @@ -459,7 +519,8 @@ int lowpan_header_decompress(struct sk_buff *skb, const struct net_device *dev,
> const void *daddr, const void *saddr)
> {
> struct ipv6hdr hdr = {};
> - u8 iphc0, iphc1;
> + struct lowpan_iphc_ctx *ci;
> + u8 iphc0, iphc1, cid = 0;
> int err;
>
> raw_dump_table(__func__, "raw skb data dump uncompressed",
> @@ -469,12 +530,14 @@ int lowpan_header_decompress(struct sk_buff *skb, const struct net_device *dev,
> lowpan_fetch_skb(skb, &iphc1, sizeof(iphc1)))
> return -EINVAL;
>
> - /* another if the CID flag is set */
> - if (iphc1 & LOWPAN_IPHC_CID)
> - return -ENOTSUPP;
> -
> hdr.version = 6;
>
> + /* default CID = 0, another if the CID flag is set */
> + if (iphc1 & LOWPAN_IPHC_CID) {
> + if (lowpan_fetch_skb(skb, &cid, sizeof(cid)))
> + return -EINVAL;
> + }
> +
> err = lowpan_iphc_tf_decompress(skb, &hdr,
> iphc0 & LOWPAN_IPHC_TF_MASK);
> if (err < 0)
> @@ -500,10 +563,18 @@ int lowpan_header_decompress(struct sk_buff *skb, const struct net_device *dev,
> }
>
> if (iphc1 & LOWPAN_IPHC_SAC) {
> - /* Source address context based uncompression */
> + spin_lock_bh(&lowpan_priv(dev)->iphc_sci.lock);
> + ci = lowpan_ctx_by_id(dev, &lowpan_priv(dev)->iphc_sci,
> + LOWPAN_IPHC_CID_SCI(cid));
> + if (!ci) {
> + spin_unlock_bh(&lowpan_priv(dev)->iphc_sci.lock);
> + return -EINVAL;
> + }
> +
> pr_debug("SAC bit is set. Handle context based source address.\n");
> - err = uncompress_context_based_src_addr(skb, &hdr.saddr,
> - iphc1 & LOWPAN_IPHC_SAM_MASK);
> + err = uncompress_ctx_addr(skb, dev, ci, &hdr.saddr,
> + iphc1 & LOWPAN_IPHC_SAM_MASK, saddr);
> + spin_unlock_bh(&lowpan_priv(dev)->iphc_sci.lock);
> } else {
> /* Source address uncompression */
> pr_debug("source address stateless compression\n");
> @@ -515,27 +586,54 @@ int lowpan_header_decompress(struct sk_buff *skb, const struct net_device *dev,
> if (err)
> return -EINVAL;
>
> - /* check for Multicast Compression */
> - if (iphc1 & LOWPAN_IPHC_M) {
> - if (iphc1 & LOWPAN_IPHC_DAC) {
> - pr_debug("dest: context-based mcast compression\n");
> - /* TODO: implement this */
> - } else {
> - err = lowpan_uncompress_multicast_daddr(skb, &hdr.daddr,
> - iphc1 & LOWPAN_IPHC_DAM_MASK);
> + switch (iphc1 & (LOWPAN_IPHC_M | LOWPAN_IPHC_DAC)) {
> + case LOWPAN_IPHC_M | LOWPAN_IPHC_DAC:
> + spin_lock_bh(&lowpan_priv(dev)->iphc_mcast_dci.lock);
> + ci = lowpan_ctx_by_id(dev, &lowpan_priv(dev)->iphc_mcast_dci,
> + LOWPAN_IPHC_CID_DCI(cid));
> + if (!ci) {
> + spin_unlock_bh(&lowpan_priv(dev)->iphc_mcast_dci.lock);
> + return -EINVAL;
> + }
>
> - if (err)
> - return -EINVAL;
> + /* multicast with context */
> + pr_debug("dest: context-based mcast compression\n");
> + err = lowpan_uncompress_multicast_ctx_daddr(skb, ci,
> + &hdr.daddr,
> + iphc1 & LOWPAN_IPHC_DAM_MASK);
> + spin_unlock_bh(&lowpan_priv(dev)->iphc_mcast_dci.lock);
> + break;
> + case LOWPAN_IPHC_M:
> + /* multicast */
> + err = lowpan_uncompress_multicast_daddr(skb, &hdr.daddr,
> + iphc1 & LOWPAN_IPHC_DAM_MASK);
> + break;
> + case LOWPAN_IPHC_DAC:
> + spin_lock_bh(&lowpan_priv(dev)->iphc_dci.lock);
> + ci = lowpan_ctx_by_id(dev, &lowpan_priv(dev)->iphc_dci,
> + LOWPAN_IPHC_CID_DCI(cid));
> + if (!ci) {
> + spin_unlock_bh(&lowpan_priv(dev)->iphc_dci.lock);
> + return -EINVAL;
> }
> - } else {
> +
> + /* Destination address context based uncompression */
> + pr_debug("DAC bit is set. Handle context based destination address.\n");
> + err = uncompress_ctx_addr(skb, dev, ci, &hdr.daddr,
> + iphc1 & LOWPAN_IPHC_DAM_MASK, daddr);
> + spin_unlock_bh(&lowpan_priv(dev)->iphc_dci.lock);
> + break;
> + default:
> err = uncompress_addr(skb, dev, &hdr.daddr,
> iphc1 & LOWPAN_IPHC_DAM_MASK, daddr);
> pr_debug("dest: stateless compression mode %d dest %pI6c\n",
> iphc1 & LOWPAN_IPHC_DAM_MASK, &hdr.daddr);
> - if (err)
> - return -EINVAL;
> + break;
> }
>
> + if (err)
> + return -EINVAL;
> +
> /* Next header data uncompression */
> if (iphc0 & LOWPAN_IPHC_NH) {
> err = lowpan_nhc_do_uncompression(skb, dev, &hdr);
> @@ -585,6 +683,60 @@ static const u8 lowpan_iphc_dam_to_sam_value[] = {
> [LOWPAN_IPHC_DAM_11] = LOWPAN_IPHC_SAM_11,
> };
>
> +static u8 lowpan_compress_ctx_addr(u8 **hc_ptr, const struct in6_addr *ipaddr,
> + const struct lowpan_iphc_ctx *ctx,
> + const unsigned char *lladdr, bool sam)
> +{
> + struct in6_addr tmp = {};
> + u8 dam;
> +
> + /* check for SAM/DAM = 11 */
> + memcpy(&tmp.s6_addr[8], lladdr, 8);
> + /* second bit-flip (Universe/Local)
> + * is done according RFC2464
> + */
> + tmp.s6_addr[8] ^= 0x02;
> + /* context information are always used */
> + ipv6_addr_prefix_cpy(&tmp, &ctx->addr, ctx->prefix_len);
> + if (ipv6_addr_equal(&tmp, ipaddr)) {
> + dam = LOWPAN_IPHC_DAM_11;
> + goto out;
> + }
> +
> + memset(&tmp, 0, sizeof(tmp));
> + /* check for SAM/DAM = 01 */
> + tmp.s6_addr[11] = 0xFF;
> + tmp.s6_addr[12] = 0xFE;
> + memcpy(&tmp.s6_addr[14], &ipaddr->s6_addr[14], 2);
> + /* context information are always used */
> + ipv6_addr_prefix_cpy(&tmp, &ctx->addr, ctx->prefix_len);
> + if (ipv6_addr_equal(&tmp, ipaddr)) {
> + lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr[14], 2);
> + dam = LOWPAN_IPHC_DAM_10;
> + goto out;
> + }
> +
> + memset(&tmp, 0, sizeof(tmp));
> + /* check for SAM/DAM = 10, should always match */
> + memcpy(&tmp.s6_addr[8], &ipaddr->s6_addr[8], 8);
> + /* context information are always used */
> + ipv6_addr_prefix_cpy(&tmp, &ctx->addr, ctx->prefix_len);
> + if (ipv6_addr_equal(&tmp, ipaddr)) {
> + lowpan_push_hc_data(hc_ptr, &ipaddr->s6_addr[8], 8);
> + dam = LOWPAN_IPHC_DAM_01;
> + goto out;
> + }
> +
> + WARN_ON_ONCE("context found but no address mode matched\n");
> + return -EINVAL;
> +out:
> +
> + if (sam)
> + return lowpan_iphc_dam_to_sam_value[dam];
> + else
> + return dam;
> +}
> +
> static u8 lowpan_compress_addr_64(u8 **hc_ptr, const struct in6_addr *ipaddr,
> const unsigned char *lladdr, bool sam)
> {
> @@ -708,6 +860,21 @@ static u8 lowpan_iphc_tf_compress(u8 **hc_ptr, const struct ipv6hdr *hdr)
> return val;
> }
>
> +static u8 lowpan_iphc_mcast_ctx_addr_compress(u8 **hc_ptr,
> + const struct lowpan_iphc_ctx *ctx,
> + const struct in6_addr *ipaddr)
> +{
> + u8 data[6];
> +
> + /* flags/scope, reserved (RIID) */
> + memcpy(data, &ipaddr->s6_addr[1], 2);
> + /* group ID */
> + memcpy(&data[1], &ipaddr->s6_addr[11], 4);
> + lowpan_push_hc_data(hc_ptr, data, 6);
> +
> + return LOWPAN_IPHC_DAM_00;
> +}
> +
> static u8 lowpan_iphc_mcast_addr_compress(u8 **hc_ptr,
> const struct in6_addr *ipaddr)
> {
> @@ -742,10 +909,11 @@ static u8 lowpan_iphc_mcast_addr_compress(u8 **hc_ptr,
> int lowpan_header_compress(struct sk_buff *skb, const struct net_device *dev,
> const void *daddr, const void *saddr)
> {
> - u8 iphc0, iphc1, *hc_ptr;
> + u8 iphc0, iphc1, *hc_ptr, cid = 0;
> struct ipv6hdr *hdr;
> u8 head[LOWPAN_IPHC_MAX_HC_BUF_LEN] = {};
> - int ret, addr_type;
> + struct lowpan_iphc_ctx *dci, *sci, dci_entry, sci_entry;
> + int ret, ipv6_daddr_type, ipv6_saddr_type;
>
> if (skb->protocol != htons(ETH_P_IPV6))
> return -EINVAL;
> @@ -769,14 +937,47 @@ int lowpan_header_compress(struct sk_buff *skb, const struct net_device *dev,
> iphc0 = LOWPAN_DISPATCH_IPHC;
> iphc1 = 0;
>
> - /* TODO: context lookup */
> -
> raw_dump_inline(__func__, "saddr", saddr, EUI64_ADDR_LEN);
> raw_dump_inline(__func__, "daddr", daddr, EUI64_ADDR_LEN);
>
> raw_dump_table(__func__, "sending raw skb network uncompressed packet",
> skb->data, skb->len);
>
> + ipv6_daddr_type = ipv6_addr_type(&hdr->daddr);
> + if (ipv6_daddr_type & IPV6_ADDR_MULTICAST) {
> + spin_lock_bh(&lowpan_priv(dev)->iphc_mcast_dci.lock);
> + dci = lowpan_ctx_by_addr(dev, &lowpan_priv(dev)->iphc_mcast_dci,
> + &hdr->daddr);
> + if (dci) {
> + memcpy(&dci_entry, dci, sizeof(*dci));
> + cid |= dci->id;
> + }
> + spin_unlock_bh(&lowpan_priv(dev)->iphc_mcast_dci.lock);
> + } else {
> + spin_lock_bh(&lowpan_priv(dev)->iphc_dci.lock);
> + dci = lowpan_ctx_by_addr(dev, &lowpan_priv(dev)->iphc_dci,
> + &hdr->daddr);
> + if (dci) {
> + memcpy(&dci_entry, dci, sizeof(*dci));
> + cid |= dci->id;
> + }
> + spin_unlock_bh(&lowpan_priv(dev)->iphc_dci.lock);
> + }
> +
> + spin_lock_bh(&lowpan_priv(dev)->iphc_sci.lock);
> + sci = lowpan_ctx_by_addr(dev, &lowpan_priv(dev)->iphc_sci,
> + &hdr->saddr);
> + if (sci) {
> + memcpy(&sci_entry, sci, sizeof(*sci));
> + cid |= (sci->id << 4);
> + }
> + spin_unlock_bh(&lowpan_priv(dev)->iphc_sci.lock);
> +
> + if (sci || dci) {
> + iphc1 |= LOWPAN_IPHC_CID;
> + lowpan_push_hc_data(&hc_ptr, &cid, sizeof(cid));
> + }
> +
> /* Traffic Class, Flow Label compression */
> iphc0 |= lowpan_iphc_tf_compress(&hc_ptr, hdr);
>
> @@ -813,39 +1014,63 @@ int lowpan_header_compress(struct sk_buff *skb, const struct net_device *dev,
> sizeof(hdr->hop_limit));
> }
>
> - addr_type = ipv6_addr_type(&hdr->saddr);
> + ipv6_saddr_type = ipv6_addr_type(&hdr->saddr);
> /* source address compression */
> - if (addr_type == IPV6_ADDR_ANY) {
> + if (ipv6_saddr_type == IPV6_ADDR_ANY) {
> pr_debug("source address is unspecified, setting SAC\n");
> iphc1 |= LOWPAN_IPHC_SAC;
> } else {
> - if (addr_type & IPV6_ADDR_LINKLOCAL) {
> - iphc1 |= lowpan_compress_addr_64(&hc_ptr, &hdr->saddr,
> - saddr, true);
> - pr_debug("source address unicast link-local %pI6c iphc1 0x%02x\n",
> - &hdr->saddr, iphc1);
> + if (sci) {
> + iphc1 |= lowpan_compress_ctx_addr(&hc_ptr, &hdr->saddr,
> + &sci_entry, saddr,
> + true);
> + iphc1 |= LOWPAN_IPHC_SAC;
> } else {
> - pr_debug("send the full source address\n");
> - lowpan_push_hc_data(&hc_ptr, hdr->saddr.s6_addr, 16);
> + if (ipv6_saddr_type & IPV6_ADDR_LINKLOCAL) {
> + iphc1 |= lowpan_compress_addr_64(&hc_ptr,
> + &hdr->saddr,
> + saddr, true);
> + pr_debug("source address unicast link-local %pI6c iphc1 0x%02x\n",
> + &hdr->saddr, iphc1);
> + } else {
> + pr_debug("send the full source address\n");
> + lowpan_push_hc_data(&hc_ptr,
> + hdr->saddr.s6_addr, 16);
> + }
> }
> }
>
> - addr_type = ipv6_addr_type(&hdr->daddr);
> /* destination address compression */
> - if (addr_type & IPV6_ADDR_MULTICAST) {
> + if (ipv6_daddr_type & IPV6_ADDR_MULTICAST) {
> pr_debug("destination address is multicast: ");
> - iphc1 |= LOWPAN_IPHC_M;
> - iphc1 |= lowpan_iphc_mcast_addr_compress(&hc_ptr, &hdr->daddr);
> + if (dci) {
> + iphc1 |= lowpan_iphc_mcast_ctx_addr_compress(&hc_ptr,
> + &dci_entry,
> + &hdr->daddr);
> + } else {
> + iphc1 |= LOWPAN_IPHC_M;
> + iphc1 |= lowpan_iphc_mcast_addr_compress(&hc_ptr,
> + &hdr->daddr);
> + }
> } else {
> - if (addr_type & IPV6_ADDR_LINKLOCAL) {
> - /* TODO: context lookup */
> - iphc1 |= lowpan_compress_addr_64(&hc_ptr, &hdr->daddr,
> - daddr, false);
> - pr_debug("dest address unicast link-local %pI6c "
> - "iphc1 0x%02x\n", &hdr->daddr, iphc1);
> + if (dci) {
> + iphc1 |= lowpan_compress_ctx_addr(&hc_ptr, &hdr->daddr,
> + &dci_entry, daddr,
> + false);
> + iphc1 |= LOWPAN_IPHC_DAC;
> } else {
> - pr_debug("dest address unicast %pI6c\n", &hdr->daddr);
> - lowpan_push_hc_data(&hc_ptr, hdr->daddr.s6_addr, 16);
> + if (ipv6_daddr_type & IPV6_ADDR_LINKLOCAL) {
> + iphc1 |= lowpan_compress_addr_64(&hc_ptr,
> + &hdr->daddr,
> + daddr, false);
> + pr_debug("dest address unicast link-local %pI6c iphc1 0x%02x\n",
> + &hdr->daddr, iphc1);
> + } else {
> + pr_debug("dest address unicast %pI6c\n",
> + &hdr->daddr);
> + lowpan_push_hc_data(&hc_ptr,
> + hdr->daddr.s6_addr, 16);
> + }
> }
> }
>
> @@ -871,3 +1096,164 @@ int lowpan_header_compress(struct sk_buff *skb, const struct net_device *dev,
> return 0;
> }
> EXPORT_SYMBOL_GPL(lowpan_header_compress);
> +
> +static bool lowpan_iphc_ctx_valid_prefix(const struct lowpan_iphc_ctx *ctx)
> +{
> + /* prefix which are smaller than 64 bits are not valid, users
> + * may mean than a prefix which is filled with zero until 64th bit.
> + * Refere rfc6282 "Any remaining bits are zero." The remaining bits
> + * in this case where are the prefix(< 64) ends until IID starts.
> + */
> + if (ctx->prefix_len < 64)
> + return false;
> +
> + return true;
> +}
> +
> +static bool
> +lowpan_iphc_mcast_ctx_valid_prefix(const struct lowpan_iphc_ctx *ctx)
> +{
> + /* network prefix for multicast is at maximum 64 bits long */
> + if (ctx->prefix_len > 64)
> + return false;
> +
> + return true;
> +}
> +
> +static int lowpan_iphc_ctx_update(struct lowpan_iphc_ctx *table,
> + const struct lowpan_iphc_ctx *ctx)
> +{
> + int ret = 0, i;
> +
> + switch (ctx->state) {
> + case LOWPAN_IPHC_CTX_STATE_DISABLED:
> + /* we don't care about if disabled */
> + break;
> + case LOWPAN_IPHC_CTX_STATE_ENABLED:
> + for (i = 0; i < LOWPAN_IPHC_CI_TABLE_SIZE; i++) {
> + if (ctx->prefix_len != table[i].prefix_len)
> + continue;
> +
> + if (ipv6_prefix_equal(&ctx->addr, &table[i].addr,
> + ctx->prefix_len)) {
> + switch (table[i].state) {
> + case LOWPAN_IPHC_CTX_STATE_ENABLED:
> + ret = -EEXIST;
> + goto out;
> + default:
> + break;
> + }
> + }
> + }
> + break;
> + default:
> + break;
> + }
> +
> + memcpy(&table[ctx->id], ctx, sizeof(*ctx));
> +
> +out:
> + return ret;
> +}
> +
> +static struct lowpan_iphc_ctx *
> +lowpan_iphc_ctx_get_by_id(const struct net_device *dev,
> + struct lowpan_iphc_ctx *table, u8 id)
> +{
> + struct lowpan_iphc_ctx *ret = NULL;
> +
> + WARN_ON_ONCE(id > LOWPAN_IPHC_CI_TABLE_SIZE);
> +
> + switch (table[id].state) {
> + case LOWPAN_IPHC_CTX_STATE_ENABLED:
> + ret = &table[id];
> + break;
> + default:
> + break;
> + }
> +
> + return ret;
> +}
> +
> +static struct lowpan_iphc_ctx *
> +lowpan_iphc_ctx_get_by_addr(const struct net_device *dev,
> + struct lowpan_iphc_ctx *table,
> + const struct in6_addr *addr)
> +{
> + struct lowpan_iphc_ctx *ret = NULL;
> + struct in6_addr addr_prefix;
> + int i;
> +
> + for (i = 0; i < LOWPAN_IPHC_CI_TABLE_SIZE; i++) {
> + ipv6_addr_prefix(&addr_prefix, addr, table[i].prefix_len);
> +
> + if (ipv6_prefix_equal(&addr_prefix, &table[i].addr,
> + table[i].prefix_len)) {
> + switch (table[i].state) {
> + case LOWPAN_IPHC_CTX_STATE_ENABLED:
> + /* remember first match */
> + if (!ret) {
> + ret = &table[i];
> + continue;
> + }
> +
> + /* get the context with longest prefix_len */
> + if (table[i].prefix_len > ret->prefix_len)
> + ret = &table[i];
> + break;
> + default:
> + break;
> + }
> + }
> + }
> +
> + return ret;
> +}
> +
> +static struct lowpan_iphc_ctx *
> +lowpan_iphc_ctx_get_by_mcast_addr(const struct net_device *dev,
> + struct lowpan_iphc_ctx *table,
> + const struct in6_addr *addr)
> +{
> + struct lowpan_iphc_ctx *ret = NULL;
> + struct in6_addr addr_mcast, network_pfx = {};
> + int i;
> +
> + /* init mcast address with */
> + memcpy(&addr_mcast, addr, sizeof(*addr));
> +
> + for (i = 0; i < LOWPAN_IPHC_CI_TABLE_SIZE; i++) {
> + /* setting plen */
> + addr_mcast.s6_addr[3] = table[i].prefix_len;
> + /* get network prefix to copy into multicast address */
> + ipv6_addr_prefix(&network_pfx, &table[i].addr,
> + table[i].prefix_len);
> + /* setting network prefix */
> + memcpy(&addr_mcast.s6_addr[4], &network_pfx, 8);
> +
> + if (ipv6_addr_equal(addr, &addr_mcast)) {
> + switch (table[i].state) {
> + case LOWPAN_IPHC_CTX_STATE_ENABLED:
> + return &table[i];
> + default:
> + break;
> + }
> + }
> + }
> +
> + return ret;
> +}
> +
> +const struct lowpan_iphc_ctx_ops iphc_ctx_unicast_ops = {
> + .valid_prefix = lowpan_iphc_ctx_valid_prefix,
> + .update = lowpan_iphc_ctx_update,
> + .get_by_id = lowpan_iphc_ctx_get_by_id,
> + .get_by_addr = lowpan_iphc_ctx_get_by_addr,
> +};
> +
> +const struct lowpan_iphc_ctx_ops iphc_ctx_mcast_ops = {
> + .valid_prefix = lowpan_iphc_mcast_ctx_valid_prefix,
> + .update = lowpan_iphc_ctx_update,
> + .get_by_id = lowpan_iphc_ctx_get_by_id,
> + .get_by_addr = lowpan_iphc_ctx_get_by_mcast_addr,
> +};
These are the comments from a first look over it. I will have a more
detailed review and actual testing once you are happy enough with it to
move it from RFC to PATCH.
regards
Stefan Schmidt
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